From 554fd8c5195424bdbcabf5de30fdc183aba391bd Mon Sep 17 00:00:00 2001 From: upstream source tree Date: Sun, 15 Mar 2015 20:14:05 -0400 Subject: obtained gcc-4.6.4.tar.bz2 from upstream website; verified gcc-4.6.4.tar.bz2.sig; imported gcc-4.6.4 source tree from verified upstream tarball. downloading a git-generated archive based on the 'upstream' tag should provide you with a source tree that is binary identical to the one extracted from the above tarball. if you have obtained the source via the command 'git clone', however, do note that line-endings of files in your working directory might differ from line-endings of the respective files in the upstream repository. --- gcc/ada/sem_ch13.adb | 7788 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 7788 insertions(+) create mode 100644 gcc/ada/sem_ch13.adb (limited to 'gcc/ada/sem_ch13.adb') diff --git a/gcc/ada/sem_ch13.adb b/gcc/ada/sem_ch13.adb new file mode 100644 index 000000000..128b398bf --- /dev/null +++ b/gcc/ada/sem_ch13.adb @@ -0,0 +1,7788 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- S E M _ C H 1 3 -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1992-2010, Free Software Foundation, Inc. -- +-- -- +-- GNAT is free software; you can redistribute it and/or modify it under -- +-- terms of the GNU General Public License as published by the Free Soft- -- +-- ware Foundation; either version 3, or (at your option) any later ver- -- +-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- +-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- +-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- +-- for more details. You should have received a copy of the GNU General -- +-- Public License distributed with GNAT; see file COPYING3. If not, go to -- +-- http://www.gnu.org/licenses for a complete copy of the license. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +with Aspects; use Aspects; +with Atree; use Atree; +with Checks; use Checks; +with Einfo; use Einfo; +with Elists; use Elists; +with Errout; use Errout; +with Exp_Disp; use Exp_Disp; +with Exp_Tss; use Exp_Tss; +with Exp_Util; use Exp_Util; +with Lib; use Lib; +with Lib.Xref; use Lib.Xref; +with Namet; use Namet; +with Nlists; use Nlists; +with Nmake; use Nmake; +with Opt; use Opt; +with Restrict; use Restrict; +with Rident; use Rident; +with Rtsfind; use Rtsfind; +with Sem; use Sem; +with Sem_Aux; use Sem_Aux; +with Sem_Ch3; use Sem_Ch3; +with Sem_Ch6; use Sem_Ch6; +with Sem_Ch8; use Sem_Ch8; +with Sem_Eval; use Sem_Eval; +with Sem_Res; use Sem_Res; +with Sem_Type; use Sem_Type; +with Sem_Util; use Sem_Util; +with Sem_Warn; use Sem_Warn; +with Sinput; use Sinput; +with Snames; use Snames; +with Stand; use Stand; +with Sinfo; use Sinfo; +with Stringt; use Stringt; +with Targparm; use Targparm; +with Ttypes; use Ttypes; +with Tbuild; use Tbuild; +with Urealp; use Urealp; + +with GNAT.Heap_Sort_G; + +package body Sem_Ch13 is + + SSU : constant Pos := System_Storage_Unit; + -- Convenient short hand for commonly used constant + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id); + -- This routine is called after setting the Esize of type entity Typ. + -- The purpose is to deal with the situation where an alignment has been + -- inherited from a derived type that is no longer appropriate for the + -- new Esize value. In this case, we reset the Alignment to unknown. + + procedure Build_Predicate_Function (Typ : Entity_Id; N : Node_Id); + -- If Typ has predicates (indicated by Has_Predicates being set for Typ, + -- then either there are pragma Invariant entries on the rep chain for the + -- type (note that Predicate aspects are converted to pragma Predicate), or + -- there are inherited aspects from a parent type, or ancestor subtypes. + -- This procedure builds the spec and body for the Predicate function that + -- tests these predicates. N is the freeze node for the type. The spec of + -- the function is inserted before the freeze node, and the body of the + -- function is inserted after the freeze node. + + procedure Build_Static_Predicate + (Typ : Entity_Id; + Expr : Node_Id; + Nam : Name_Id); + -- Given a predicated type Typ, where Typ is a discrete static subtype, + -- whose predicate expression is Expr, tests if Expr is a static predicate, + -- and if so, builds the predicate range list. Nam is the name of the one + -- argument to the predicate function. Occurrences of the type name in the + -- predicate expression have been replaced by identifier references to this + -- name, which is unique, so any identifier with Chars matching Nam must be + -- a reference to the type. If the predicate is non-static, this procedure + -- returns doing nothing. If the predicate is static, then the predicate + -- list is stored in Static_Predicate (Typ), and the Expr is rewritten as + -- a canonicalized membership operation. + + function Get_Alignment_Value (Expr : Node_Id) return Uint; + -- Given the expression for an alignment value, returns the corresponding + -- Uint value. If the value is inappropriate, then error messages are + -- posted as required, and a value of No_Uint is returned. + + function Is_Operational_Item (N : Node_Id) return Boolean; + -- A specification for a stream attribute is allowed before the full type + -- is declared, as explained in AI-00137 and the corrigendum. Attributes + -- that do not specify a representation characteristic are operational + -- attributes. + + procedure New_Stream_Subprogram + (N : Node_Id; + Ent : Entity_Id; + Subp : Entity_Id; + Nam : TSS_Name_Type); + -- Create a subprogram renaming of a given stream attribute to the + -- designated subprogram and then in the tagged case, provide this as a + -- primitive operation, or in the non-tagged case make an appropriate TSS + -- entry. This is more properly an expansion activity than just semantics, + -- but the presence of user-defined stream functions for limited types is a + -- legality check, which is why this takes place here rather than in + -- exp_ch13, where it was previously. Nam indicates the name of the TSS + -- function to be generated. + -- + -- To avoid elaboration anomalies with freeze nodes, for untagged types + -- we generate both a subprogram declaration and a subprogram renaming + -- declaration, so that the attribute specification is handled as a + -- renaming_as_body. For tagged types, the specification is one of the + -- primitive specs. + + generic + with procedure Replace_Type_Reference (N : Node_Id); + procedure Replace_Type_References_Generic (N : Node_Id; TName : Name_Id); + -- This is used to scan an expression for a predicate or invariant aspect + -- replacing occurrences of the name TName (the name of the subtype to + -- which the aspect applies) with appropriate references to the parameter + -- of the predicate function or invariant procedure. The procedure passed + -- as a generic parameter does the actual replacement of node N, which is + -- either a simple direct reference to TName, or a selected component that + -- represents an appropriately qualified occurrence of TName. + + procedure Set_Biased + (E : Entity_Id; + N : Node_Id; + Msg : String; + Biased : Boolean := True); + -- If Biased is True, sets Has_Biased_Representation flag for E, and + -- outputs a warning message at node N if Warn_On_Biased_Representation is + -- is True. This warning inserts the string Msg to describe the construct + -- causing biasing. + + ---------------------------------------------- + -- Table for Validate_Unchecked_Conversions -- + ---------------------------------------------- + + -- The following table collects unchecked conversions for validation. + -- Entries are made by Validate_Unchecked_Conversion and then the + -- call to Validate_Unchecked_Conversions does the actual error + -- checking and posting of warnings. The reason for this delayed + -- processing is to take advantage of back-annotations of size and + -- alignment values performed by the back end. + + -- Note: the reason we store a Source_Ptr value instead of a Node_Id + -- is that by the time Validate_Unchecked_Conversions is called, Sprint + -- will already have modified all Sloc values if the -gnatD option is set. + + type UC_Entry is record + Eloc : Source_Ptr; -- node used for posting warnings + Source : Entity_Id; -- source type for unchecked conversion + Target : Entity_Id; -- target type for unchecked conversion + end record; + + package Unchecked_Conversions is new Table.Table ( + Table_Component_Type => UC_Entry, + Table_Index_Type => Int, + Table_Low_Bound => 1, + Table_Initial => 50, + Table_Increment => 200, + Table_Name => "Unchecked_Conversions"); + + ---------------------------------------- + -- Table for Validate_Address_Clauses -- + ---------------------------------------- + + -- If an address clause has the form + + -- for X'Address use Expr + + -- where Expr is of the form Y'Address or recursively is a reference + -- to a constant of either of these forms, and X and Y are entities of + -- objects, then if Y has a smaller alignment than X, that merits a + -- warning about possible bad alignment. The following table collects + -- address clauses of this kind. We put these in a table so that they + -- can be checked after the back end has completed annotation of the + -- alignments of objects, since we can catch more cases that way. + + type Address_Clause_Check_Record is record + N : Node_Id; + -- The address clause + + X : Entity_Id; + -- The entity of the object overlaying Y + + Y : Entity_Id; + -- The entity of the object being overlaid + + Off : Boolean; + -- Whether the address is offset within Y + end record; + + package Address_Clause_Checks is new Table.Table ( + Table_Component_Type => Address_Clause_Check_Record, + Table_Index_Type => Int, + Table_Low_Bound => 1, + Table_Initial => 20, + Table_Increment => 200, + Table_Name => "Address_Clause_Checks"); + + ----------------------------------------- + -- Adjust_Record_For_Reverse_Bit_Order -- + ----------------------------------------- + + procedure Adjust_Record_For_Reverse_Bit_Order (R : Entity_Id) is + Comp : Node_Id; + CC : Node_Id; + + begin + -- Processing depends on version of Ada + + -- For Ada 95, we just renumber bits within a storage unit. We do the + -- same for Ada 83 mode, since we recognize pragma Bit_Order in Ada 83, + -- and are free to add this extension. + + if Ada_Version < Ada_2005 then + Comp := First_Component_Or_Discriminant (R); + while Present (Comp) loop + CC := Component_Clause (Comp); + + -- If component clause is present, then deal with the non-default + -- bit order case for Ada 95 mode. + + -- We only do this processing for the base type, and in fact that + -- is important, since otherwise if there are record subtypes, we + -- could reverse the bits once for each subtype, which is wrong. + + if Present (CC) + and then Ekind (R) = E_Record_Type + then + declare + CFB : constant Uint := Component_Bit_Offset (Comp); + CSZ : constant Uint := Esize (Comp); + CLC : constant Node_Id := Component_Clause (Comp); + Pos : constant Node_Id := Position (CLC); + FB : constant Node_Id := First_Bit (CLC); + + Storage_Unit_Offset : constant Uint := + CFB / System_Storage_Unit; + + Start_Bit : constant Uint := + CFB mod System_Storage_Unit; + + begin + -- Cases where field goes over storage unit boundary + + if Start_Bit + CSZ > System_Storage_Unit then + + -- Allow multi-byte field but generate warning + + if Start_Bit mod System_Storage_Unit = 0 + and then CSZ mod System_Storage_Unit = 0 + then + Error_Msg_N + ("multi-byte field specified with non-standard" + & " Bit_Order?", CLC); + + if Bytes_Big_Endian then + Error_Msg_N + ("bytes are not reversed " + & "(component is big-endian)?", CLC); + else + Error_Msg_N + ("bytes are not reversed " + & "(component is little-endian)?", CLC); + end if; + + -- Do not allow non-contiguous field + + else + Error_Msg_N + ("attempt to specify non-contiguous field " + & "not permitted", CLC); + Error_Msg_N + ("\caused by non-standard Bit_Order " + & "specified", CLC); + Error_Msg_N + ("\consider possibility of using " + & "Ada 2005 mode here", CLC); + end if; + + -- Case where field fits in one storage unit + + else + -- Give warning if suspicious component clause + + if Intval (FB) >= System_Storage_Unit + and then Warn_On_Reverse_Bit_Order + then + Error_Msg_N + ("?Bit_Order clause does not affect " & + "byte ordering", Pos); + Error_Msg_Uint_1 := + Intval (Pos) + Intval (FB) / + System_Storage_Unit; + Error_Msg_N + ("?position normalized to ^ before bit " & + "order interpreted", Pos); + end if; + + -- Here is where we fix up the Component_Bit_Offset value + -- to account for the reverse bit order. Some examples of + -- what needs to be done are: + + -- First_Bit .. Last_Bit Component_Bit_Offset + -- old new old new + + -- 0 .. 0 7 .. 7 0 7 + -- 0 .. 1 6 .. 7 0 6 + -- 0 .. 2 5 .. 7 0 5 + -- 0 .. 7 0 .. 7 0 4 + + -- 1 .. 1 6 .. 6 1 6 + -- 1 .. 4 3 .. 6 1 3 + -- 4 .. 7 0 .. 3 4 0 + + -- The rule is that the first bit is is obtained by + -- subtracting the old ending bit from storage_unit - 1. + + Set_Component_Bit_Offset + (Comp, + (Storage_Unit_Offset * System_Storage_Unit) + + (System_Storage_Unit - 1) - + (Start_Bit + CSZ - 1)); + + Set_Normalized_First_Bit + (Comp, + Component_Bit_Offset (Comp) mod + System_Storage_Unit); + end if; + end; + end if; + + Next_Component_Or_Discriminant (Comp); + end loop; + + -- For Ada 2005, we do machine scalar processing, as fully described In + -- AI-133. This involves gathering all components which start at the + -- same byte offset and processing them together. Same approach is still + -- valid in later versions including Ada 2012. + + else + declare + Max_Machine_Scalar_Size : constant Uint := + UI_From_Int + (Standard_Long_Long_Integer_Size); + -- We use this as the maximum machine scalar size + + Num_CC : Natural; + SSU : constant Uint := UI_From_Int (System_Storage_Unit); + + begin + -- This first loop through components does two things. First it + -- deals with the case of components with component clauses whose + -- length is greater than the maximum machine scalar size (either + -- accepting them or rejecting as needed). Second, it counts the + -- number of components with component clauses whose length does + -- not exceed this maximum for later processing. + + Num_CC := 0; + Comp := First_Component_Or_Discriminant (R); + while Present (Comp) loop + CC := Component_Clause (Comp); + + if Present (CC) then + declare + Fbit : constant Uint := + Static_Integer (First_Bit (CC)); + Lbit : constant Uint := + Static_Integer (Last_Bit (CC)); + + begin + -- Case of component with last bit >= max machine scalar + + if Lbit >= Max_Machine_Scalar_Size then + + -- This is allowed only if first bit is zero, and + -- last bit + 1 is a multiple of storage unit size. + + if Fbit = 0 and then (Lbit + 1) mod SSU = 0 then + + -- This is the case to give a warning if enabled + + if Warn_On_Reverse_Bit_Order then + Error_Msg_N + ("multi-byte field specified with " + & " non-standard Bit_Order?", CC); + + if Bytes_Big_Endian then + Error_Msg_N + ("\bytes are not reversed " + & "(component is big-endian)?", CC); + else + Error_Msg_N + ("\bytes are not reversed " + & "(component is little-endian)?", CC); + end if; + end if; + + -- Give error message for RM 13.4.1(10) violation + + else + Error_Msg_FE + ("machine scalar rules not followed for&", + First_Bit (CC), Comp); + + Error_Msg_Uint_1 := Lbit; + Error_Msg_Uint_2 := Max_Machine_Scalar_Size; + Error_Msg_F + ("\last bit (^) exceeds maximum machine " + & "scalar size (^)", + First_Bit (CC)); + + if (Lbit + 1) mod SSU /= 0 then + Error_Msg_Uint_1 := SSU; + Error_Msg_F + ("\and is not a multiple of Storage_Unit (^) " + & "('R'M 13.4.1(10))", + First_Bit (CC)); + + else + Error_Msg_Uint_1 := Fbit; + Error_Msg_F + ("\and first bit (^) is non-zero " + & "('R'M 13.4.1(10))", + First_Bit (CC)); + end if; + end if; + + -- OK case of machine scalar related component clause, + -- For now, just count them. + + else + Num_CC := Num_CC + 1; + end if; + end; + end if; + + Next_Component_Or_Discriminant (Comp); + end loop; + + -- We need to sort the component clauses on the basis of the + -- Position values in the clause, so we can group clauses with + -- the same Position. together to determine the relevant machine + -- scalar size. + + Sort_CC : declare + Comps : array (0 .. Num_CC) of Entity_Id; + -- Array to collect component and discriminant entities. The + -- data starts at index 1, the 0'th entry is for the sort + -- routine. + + function CP_Lt (Op1, Op2 : Natural) return Boolean; + -- Compare routine for Sort + + procedure CP_Move (From : Natural; To : Natural); + -- Move routine for Sort + + package Sorting is new GNAT.Heap_Sort_G (CP_Move, CP_Lt); + + Start : Natural; + Stop : Natural; + -- Start and stop positions in the component list of the set of + -- components with the same starting position (that constitute + -- components in a single machine scalar). + + MaxL : Uint; + -- Maximum last bit value of any component in this set + + MSS : Uint; + -- Corresponding machine scalar size + + ----------- + -- CP_Lt -- + ----------- + + function CP_Lt (Op1, Op2 : Natural) return Boolean is + begin + return Position (Component_Clause (Comps (Op1))) < + Position (Component_Clause (Comps (Op2))); + end CP_Lt; + + ------------- + -- CP_Move -- + ------------- + + procedure CP_Move (From : Natural; To : Natural) is + begin + Comps (To) := Comps (From); + end CP_Move; + + -- Start of processing for Sort_CC + + begin + -- Collect the machine scalar relevant component clauses + + Num_CC := 0; + Comp := First_Component_Or_Discriminant (R); + while Present (Comp) loop + declare + CC : constant Node_Id := Component_Clause (Comp); + + begin + -- Collect only component clauses whose last bit is less + -- than machine scalar size. Any component clause whose + -- last bit exceeds this value does not take part in + -- machine scalar layout considerations. The test for + -- Error_Posted makes sure we exclude component clauses + -- for which we already posted an error. + + if Present (CC) + and then not Error_Posted (Last_Bit (CC)) + and then Static_Integer (Last_Bit (CC)) < + Max_Machine_Scalar_Size + then + Num_CC := Num_CC + 1; + Comps (Num_CC) := Comp; + end if; + end; + + Next_Component_Or_Discriminant (Comp); + end loop; + + -- Sort by ascending position number + + Sorting.Sort (Num_CC); + + -- We now have all the components whose size does not exceed + -- the max machine scalar value, sorted by starting position. + -- In this loop we gather groups of clauses starting at the + -- same position, to process them in accordance with AI-133. + + Stop := 0; + while Stop < Num_CC loop + Start := Stop + 1; + Stop := Start; + MaxL := + Static_Integer + (Last_Bit (Component_Clause (Comps (Start)))); + while Stop < Num_CC loop + if Static_Integer + (Position (Component_Clause (Comps (Stop + 1)))) = + Static_Integer + (Position (Component_Clause (Comps (Stop)))) + then + Stop := Stop + 1; + MaxL := + UI_Max + (MaxL, + Static_Integer + (Last_Bit + (Component_Clause (Comps (Stop))))); + else + exit; + end if; + end loop; + + -- Now we have a group of component clauses from Start to + -- Stop whose positions are identical, and MaxL is the + -- maximum last bit value of any of these components. + + -- We need to determine the corresponding machine scalar + -- size. This loop assumes that machine scalar sizes are + -- even, and that each possible machine scalar has twice + -- as many bits as the next smaller one. + + MSS := Max_Machine_Scalar_Size; + while MSS mod 2 = 0 + and then (MSS / 2) >= SSU + and then (MSS / 2) > MaxL + loop + MSS := MSS / 2; + end loop; + + -- Here is where we fix up the Component_Bit_Offset value + -- to account for the reverse bit order. Some examples of + -- what needs to be done for the case of a machine scalar + -- size of 8 are: + + -- First_Bit .. Last_Bit Component_Bit_Offset + -- old new old new + + -- 0 .. 0 7 .. 7 0 7 + -- 0 .. 1 6 .. 7 0 6 + -- 0 .. 2 5 .. 7 0 5 + -- 0 .. 7 0 .. 7 0 4 + + -- 1 .. 1 6 .. 6 1 6 + -- 1 .. 4 3 .. 6 1 3 + -- 4 .. 7 0 .. 3 4 0 + + -- The rule is that the first bit is obtained by subtracting + -- the old ending bit from machine scalar size - 1. + + for C in Start .. Stop loop + declare + Comp : constant Entity_Id := Comps (C); + CC : constant Node_Id := + Component_Clause (Comp); + LB : constant Uint := + Static_Integer (Last_Bit (CC)); + NFB : constant Uint := MSS - Uint_1 - LB; + NLB : constant Uint := NFB + Esize (Comp) - 1; + Pos : constant Uint := + Static_Integer (Position (CC)); + + begin + if Warn_On_Reverse_Bit_Order then + Error_Msg_Uint_1 := MSS; + Error_Msg_N + ("info: reverse bit order in machine " & + "scalar of length^?", First_Bit (CC)); + Error_Msg_Uint_1 := NFB; + Error_Msg_Uint_2 := NLB; + + if Bytes_Big_Endian then + Error_Msg_NE + ("?\info: big-endian range for " + & "component & is ^ .. ^", + First_Bit (CC), Comp); + else + Error_Msg_NE + ("?\info: little-endian range " + & "for component & is ^ .. ^", + First_Bit (CC), Comp); + end if; + end if; + + Set_Component_Bit_Offset (Comp, Pos * SSU + NFB); + Set_Normalized_First_Bit (Comp, NFB mod SSU); + end; + end loop; + end loop; + end Sort_CC; + end; + end if; + end Adjust_Record_For_Reverse_Bit_Order; + + -------------------------------------- + -- Alignment_Check_For_Esize_Change -- + -------------------------------------- + + procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id) is + begin + -- If the alignment is known, and not set by a rep clause, and is + -- inconsistent with the size being set, then reset it to unknown, + -- we assume in this case that the size overrides the inherited + -- alignment, and that the alignment must be recomputed. + + if Known_Alignment (Typ) + and then not Has_Alignment_Clause (Typ) + and then Esize (Typ) mod (Alignment (Typ) * SSU) /= 0 + then + Init_Alignment (Typ); + end if; + end Alignment_Check_For_Esize_Change; + + ----------------------------------- + -- Analyze_Aspect_Specifications -- + ----------------------------------- + + procedure Analyze_Aspect_Specifications + (N : Node_Id; + E : Entity_Id; + L : List_Id) + is + Aspect : Node_Id; + Aitem : Node_Id; + Ent : Node_Id; + + Ins_Node : Node_Id := N; + -- Insert pragmas (except Pre/Post/Invariant/Predicate) after this node + + -- The general processing involves building an attribute definition + -- clause or a pragma node that corresponds to the access type. Then + -- one of two things happens: + + -- If we are required to delay the evaluation of this aspect to the + -- freeze point, we preanalyze the relevant argument, and then attach + -- the corresponding pragma/attribute definition clause to the aspect + -- specification node, which is then placed in the Rep Item chain. + -- In this case we mark the entity with the Has_Delayed_Aspects flag, + -- and we evaluate the rep item at the freeze point. + + -- If no delay is required, we just insert the pragma or attribute + -- after the declaration, and it will get processed by the normal + -- circuit. The From_Aspect_Specification flag is set on the pragma + -- or attribute definition node in either case to activate special + -- processing (e.g. not traversing the list of homonyms for inline). + + Delay_Required : Boolean; + -- Set True if delay is required + + begin + -- Return if no aspects + + if L = No_List then + return; + end if; + + -- Return if already analyzed (avoids duplicate calls in some cases + -- where type declarations get rewritten and processed twice). + + if Analyzed (N) then + return; + end if; + + -- Loop through aspects + + Aspect := First (L); + while Present (Aspect) loop + declare + Loc : constant Source_Ptr := Sloc (Aspect); + Id : constant Node_Id := Identifier (Aspect); + Expr : constant Node_Id := Expression (Aspect); + Nam : constant Name_Id := Chars (Id); + A_Id : constant Aspect_Id := Get_Aspect_Id (Nam); + Anod : Node_Id; + T : Entity_Id; + + Eloc : Source_Ptr := Sloc (Expr); + -- Source location of expression, modified when we split PPC's + + begin + Set_Entity (Aspect, E); + Ent := New_Occurrence_Of (E, Sloc (Id)); + + -- Check for duplicate aspect. Note that the Comes_From_Source + -- test allows duplicate Pre/Post's that we generate internally + -- to escape being flagged here. + + Anod := First (L); + while Anod /= Aspect loop + if Nam = Chars (Identifier (Anod)) + and then Comes_From_Source (Aspect) + then + Error_Msg_Name_1 := Nam; + Error_Msg_Sloc := Sloc (Anod); + + -- Case of same aspect specified twice + + if Class_Present (Anod) = Class_Present (Aspect) then + if not Class_Present (Anod) then + Error_Msg_NE + ("aspect% for & previously given#", + Id, E); + else + Error_Msg_NE + ("aspect `%''Class` for & previously given#", + Id, E); + end if; + + -- Case of Pre and Pre'Class both specified + + elsif Nam = Name_Pre then + if Class_Present (Aspect) then + Error_Msg_NE + ("aspect `Pre''Class` for & is not allowed here", + Id, E); + Error_Msg_NE + ("\since aspect `Pre` previously given#", + Id, E); + + else + Error_Msg_NE + ("aspect `Pre` for & is not allowed here", + Id, E); + Error_Msg_NE + ("\since aspect `Pre''Class` previously given#", + Id, E); + end if; + end if; + + goto Continue; + end if; + + Next (Anod); + end loop; + + -- Processing based on specific aspect + + case A_Id is + + -- No_Aspect should be impossible + + when No_Aspect => + raise Program_Error; + + -- Aspects taking an optional boolean argument. For all of + -- these we just create a matching pragma and insert it, + -- setting flag Cancel_Aspect if the expression is False. + + when Aspect_Ada_2005 | + Aspect_Ada_2012 | + Aspect_Atomic | + Aspect_Atomic_Components | + Aspect_Discard_Names | + Aspect_Favor_Top_Level | + Aspect_Inline | + Aspect_Inline_Always | + Aspect_No_Return | + Aspect_Pack | + Aspect_Persistent_BSS | + Aspect_Preelaborable_Initialization | + Aspect_Pure_Function | + Aspect_Shared | + Aspect_Suppress_Debug_Info | + Aspect_Unchecked_Union | + Aspect_Universal_Aliasing | + Aspect_Unmodified | + Aspect_Unreferenced | + Aspect_Unreferenced_Objects | + Aspect_Volatile | + Aspect_Volatile_Components => + + -- Build corresponding pragma node + + Aitem := + Make_Pragma (Loc, + Pragma_Argument_Associations => New_List (Ent), + Pragma_Identifier => + Make_Identifier (Sloc (Id), Chars (Id))); + + -- Deal with missing expression case, delay never needed + + if No (Expr) then + Delay_Required := False; + + -- Expression is present + + else + Preanalyze_Spec_Expression (Expr, Standard_Boolean); + + -- If preanalysis gives a static expression, we don't + -- need to delay (this will happen often in practice). + + if Is_OK_Static_Expression (Expr) then + Delay_Required := False; + + if Is_False (Expr_Value (Expr)) then + Set_Aspect_Cancel (Aitem); + end if; + + -- If we don't get a static expression, then delay, the + -- expression may turn out static by freeze time. + + else + Delay_Required := True; + end if; + end if; + + -- Aspects corresponding to attribute definition clauses + + when Aspect_Address | + Aspect_Alignment | + Aspect_Bit_Order | + Aspect_Component_Size | + Aspect_External_Tag | + Aspect_Machine_Radix | + Aspect_Object_Size | + Aspect_Size | + Aspect_Storage_Pool | + Aspect_Storage_Size | + Aspect_Stream_Size | + Aspect_Value_Size => + + -- Preanalyze the expression with the appropriate type + + case A_Id is + when Aspect_Address => + T := RTE (RE_Address); + when Aspect_Bit_Order => + T := RTE (RE_Bit_Order); + when Aspect_External_Tag => + T := Standard_String; + when Aspect_Storage_Pool => + T := Class_Wide_Type (RTE (RE_Root_Storage_Pool)); + when others => + T := Any_Integer; + end case; + + Preanalyze_Spec_Expression (Expr, T); + + -- Construct the attribute definition clause + + Aitem := + Make_Attribute_Definition_Clause (Loc, + Name => Ent, + Chars => Chars (Id), + Expression => Relocate_Node (Expr)); + + -- We do not need a delay if we have a static expression + + if Is_OK_Static_Expression (Expression (Aitem)) then + Delay_Required := False; + + -- Here a delay is required + + else + Delay_Required := True; + end if; + + -- Aspects corresponding to pragmas with two arguments, where + -- the first argument is a local name referring to the entity, + -- and the second argument is the aspect definition expression. + + when Aspect_Suppress | + Aspect_Unsuppress => + + -- Construct the pragma + + Aitem := + Make_Pragma (Loc, + Pragma_Argument_Associations => New_List ( + New_Occurrence_Of (E, Eloc), + Relocate_Node (Expr)), + Pragma_Identifier => + Make_Identifier (Sloc (Id), Chars (Id))); + + -- We don't have to play the delay game here, since the only + -- values are check names which don't get analyzed anyway. + + Delay_Required := False; + + -- Aspects corresponding to stream routines + + when Aspect_Input | + Aspect_Output | + Aspect_Read | + Aspect_Write => + + -- Construct the attribute definition clause + + Aitem := + Make_Attribute_Definition_Clause (Loc, + Name => Ent, + Chars => Chars (Id), + Expression => Relocate_Node (Expr)); + + -- These are always delayed (typically the subprogram that + -- is referenced cannot have been declared yet, since it has + -- a reference to the type for which this aspect is defined. + + Delay_Required := True; + + -- Aspects corresponding to pragmas with two arguments, where + -- the second argument is a local name referring to the entity, + -- and the first argument is the aspect definition expression. + + when Aspect_Warnings => + + -- Construct the pragma + + Aitem := + Make_Pragma (Loc, + Pragma_Argument_Associations => New_List ( + Relocate_Node (Expr), + New_Occurrence_Of (E, Eloc)), + Pragma_Identifier => + Make_Identifier (Sloc (Id), Chars (Id)), + Class_Present => Class_Present (Aspect)); + + -- We don't have to play the delay game here, since the only + -- values are check names which don't get analyzed anyway. + + Delay_Required := False; + + -- Aspects Pre/Post generate Precondition/Postcondition pragmas + -- with a first argument that is the expression, and a second + -- argument that is an informative message if the test fails. + -- This is inserted right after the declaration, to get the + -- required pragma placement. The processing for the pragmas + -- takes care of the required delay. + + when Aspect_Pre | Aspect_Post => declare + Pname : Name_Id; + + begin + if A_Id = Aspect_Pre then + Pname := Name_Precondition; + else + Pname := Name_Postcondition; + end if; + + -- If the expressions is of the form A and then B, then + -- we generate separate Pre/Post aspects for the separate + -- clauses. Since we allow multiple pragmas, there is no + -- problem in allowing multiple Pre/Post aspects internally. + + -- We do not do this for Pre'Class, since we have to put + -- these conditions together in a complex OR expression + + if Pname = Name_Postcondition + or else not Class_Present (Aspect) + then + while Nkind (Expr) = N_And_Then loop + Insert_After (Aspect, + Make_Aspect_Specification (Sloc (Right_Opnd (Expr)), + Identifier => Identifier (Aspect), + Expression => Relocate_Node (Right_Opnd (Expr)), + Class_Present => Class_Present (Aspect), + Split_PPC => True)); + Rewrite (Expr, Relocate_Node (Left_Opnd (Expr))); + Eloc := Sloc (Expr); + end loop; + end if; + + -- Build the precondition/postcondition pragma + + Aitem := + Make_Pragma (Loc, + Pragma_Identifier => + Make_Identifier (Sloc (Id), Pname), + Class_Present => Class_Present (Aspect), + Split_PPC => Split_PPC (Aspect), + Pragma_Argument_Associations => New_List ( + Make_Pragma_Argument_Association (Eloc, + Chars => Name_Check, + Expression => Relocate_Node (Expr)))); + + -- Add message unless exception messages are suppressed + + if not Opt.Exception_Locations_Suppressed then + Append_To (Pragma_Argument_Associations (Aitem), + Make_Pragma_Argument_Association (Eloc, + Chars => Name_Message, + Expression => + Make_String_Literal (Eloc, + Strval => "failed " + & Get_Name_String (Pname) + & " from " + & Build_Location_String (Eloc)))); + end if; + + Set_From_Aspect_Specification (Aitem, True); + + -- For Pre/Post cases, insert immediately after the entity + -- declaration, since that is the required pragma placement. + -- Note that for these aspects, we do not have to worry + -- about delay issues, since the pragmas themselves deal + -- with delay of visibility for the expression analysis. + + -- If the entity is a library-level subprogram, the pre/ + -- postconditions must be treated as late pragmas. + + if Nkind (Parent (N)) = N_Compilation_Unit then + Add_Global_Declaration (Aitem); + else + Insert_After (N, Aitem); + end if; + + goto Continue; + end; + + -- Invariant aspects generate a corresponding pragma with a + -- first argument that is the entity, a second argument that is + -- the expression and a third argument that is an appropriate + -- message. This is inserted right after the declaration, to + -- get the required pragma placement. The pragma processing + -- takes care of the required delay. + + when Aspect_Invariant => + + -- Construct the pragma + + Aitem := + Make_Pragma (Loc, + Pragma_Argument_Associations => + New_List (Ent, Relocate_Node (Expr)), + Class_Present => Class_Present (Aspect), + Pragma_Identifier => + Make_Identifier (Sloc (Id), Name_Invariant)); + + -- Add message unless exception messages are suppressed + + if not Opt.Exception_Locations_Suppressed then + Append_To (Pragma_Argument_Associations (Aitem), + Make_Pragma_Argument_Association (Eloc, + Chars => Name_Message, + Expression => + Make_String_Literal (Eloc, + Strval => "failed invariant from " + & Build_Location_String (Eloc)))); + end if; + + Set_From_Aspect_Specification (Aitem, True); + + -- For Invariant case, insert immediately after the entity + -- declaration. We do not have to worry about delay issues + -- since the pragma processing takes care of this. + + Insert_After (N, Aitem); + goto Continue; + + -- Predicate aspects generate a corresponding pragma with a + -- first argument that is the entity, and the second argument + -- is the expression. This is inserted immediately after the + -- declaration, to get the required pragma placement. The + -- pragma processing takes care of the required delay. + + when Aspect_Predicate => + + -- Construct the pragma + + Aitem := + Make_Pragma (Loc, + Pragma_Argument_Associations => + New_List (Ent, Relocate_Node (Expr)), + Class_Present => Class_Present (Aspect), + Pragma_Identifier => + Make_Identifier (Sloc (Id), Name_Predicate)); + + Set_From_Aspect_Specification (Aitem, True); + + -- Make sure we have a freeze node (it might otherwise be + -- missing in cases like subtype X is Y, and we would not + -- have a place to build the predicate function). + + Ensure_Freeze_Node (E); + + -- For Predicate case, insert immediately after the entity + -- declaration. We do not have to worry about delay issues + -- since the pragma processing takes care of this. + + Insert_After (N, Aitem); + goto Continue; + end case; + + Set_From_Aspect_Specification (Aitem, True); + + -- If a delay is required, we delay the freeze (not much point in + -- delaying the aspect if we don't delay the freeze!). The pragma + -- or clause is then attached to the aspect specification which + -- is placed in the rep item list. + + if Delay_Required then + Ensure_Freeze_Node (E); + Set_Is_Delayed_Aspect (Aitem); + Set_Has_Delayed_Aspects (E); + Set_Aspect_Rep_Item (Aspect, Aitem); + Record_Rep_Item (E, Aspect); + + -- If no delay required, insert the pragma/clause in the tree + + else + -- For Pre/Post cases, insert immediately after the entity + -- declaration, since that is the required pragma placement. + + if A_Id = Aspect_Pre or else A_Id = Aspect_Post then + Insert_After (N, Aitem); + + -- For all other cases, insert in sequence + + else + Insert_After (Ins_Node, Aitem); + Ins_Node := Aitem; + end if; + end if; + end; + + <> + Next (Aspect); + end loop; + end Analyze_Aspect_Specifications; + + ----------------------- + -- Analyze_At_Clause -- + ----------------------- + + -- An at clause is replaced by the corresponding Address attribute + -- definition clause that is the preferred approach in Ada 95. + + procedure Analyze_At_Clause (N : Node_Id) is + CS : constant Boolean := Comes_From_Source (N); + + begin + -- This is an obsolescent feature + + Check_Restriction (No_Obsolescent_Features, N); + + if Warn_On_Obsolescent_Feature then + Error_Msg_N + ("at clause is an obsolescent feature (RM J.7(2))?", N); + Error_Msg_N + ("\use address attribute definition clause instead?", N); + end if; + + -- Rewrite as address clause + + Rewrite (N, + Make_Attribute_Definition_Clause (Sloc (N), + Name => Identifier (N), + Chars => Name_Address, + Expression => Expression (N))); + + -- We preserve Comes_From_Source, since logically the clause still + -- comes from the source program even though it is changed in form. + + Set_Comes_From_Source (N, CS); + + -- Analyze rewritten clause + + Analyze_Attribute_Definition_Clause (N); + end Analyze_At_Clause; + + ----------------------------------------- + -- Analyze_Attribute_Definition_Clause -- + ----------------------------------------- + + procedure Analyze_Attribute_Definition_Clause (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Nam : constant Node_Id := Name (N); + Attr : constant Name_Id := Chars (N); + Expr : constant Node_Id := Expression (N); + Id : constant Attribute_Id := Get_Attribute_Id (Attr); + Ent : Entity_Id; + U_Ent : Entity_Id; + + FOnly : Boolean := False; + -- Reset to True for subtype specific attribute (Alignment, Size) + -- and for stream attributes, i.e. those cases where in the call + -- to Rep_Item_Too_Late, FOnly is set True so that only the freezing + -- rules are checked. Note that the case of stream attributes is not + -- clear from the RM, but see AI95-00137. Also, the RM seems to + -- disallow Storage_Size for derived task types, but that is also + -- clearly unintentional. + + procedure Analyze_Stream_TSS_Definition (TSS_Nam : TSS_Name_Type); + -- Common processing for 'Read, 'Write, 'Input and 'Output attribute + -- definition clauses. + + function Duplicate_Clause return Boolean; + -- This routine checks if the aspect for U_Ent being given by attribute + -- definition clause N is for an aspect that has already been specified, + -- and if so gives an error message. If there is a duplicate, True is + -- returned, otherwise if there is no error, False is returned. + + ----------------------------------- + -- Analyze_Stream_TSS_Definition -- + ----------------------------------- + + procedure Analyze_Stream_TSS_Definition (TSS_Nam : TSS_Name_Type) is + Subp : Entity_Id := Empty; + I : Interp_Index; + It : Interp; + Pnam : Entity_Id; + + Is_Read : constant Boolean := (TSS_Nam = TSS_Stream_Read); + + function Has_Good_Profile (Subp : Entity_Id) return Boolean; + -- Return true if the entity is a subprogram with an appropriate + -- profile for the attribute being defined. + + ---------------------- + -- Has_Good_Profile -- + ---------------------- + + function Has_Good_Profile (Subp : Entity_Id) return Boolean is + F : Entity_Id; + Is_Function : constant Boolean := (TSS_Nam = TSS_Stream_Input); + Expected_Ekind : constant array (Boolean) of Entity_Kind := + (False => E_Procedure, True => E_Function); + Typ : Entity_Id; + + begin + if Ekind (Subp) /= Expected_Ekind (Is_Function) then + return False; + end if; + + F := First_Formal (Subp); + + if No (F) + or else Ekind (Etype (F)) /= E_Anonymous_Access_Type + or else Designated_Type (Etype (F)) /= + Class_Wide_Type (RTE (RE_Root_Stream_Type)) + then + return False; + end if; + + if not Is_Function then + Next_Formal (F); + + declare + Expected_Mode : constant array (Boolean) of Entity_Kind := + (False => E_In_Parameter, + True => E_Out_Parameter); + begin + if Parameter_Mode (F) /= Expected_Mode (Is_Read) then + return False; + end if; + end; + + Typ := Etype (F); + + else + Typ := Etype (Subp); + end if; + + return Base_Type (Typ) = Base_Type (Ent) + and then No (Next_Formal (F)); + end Has_Good_Profile; + + -- Start of processing for Analyze_Stream_TSS_Definition + + begin + FOnly := True; + + if not Is_Type (U_Ent) then + Error_Msg_N ("local name must be a subtype", Nam); + return; + end if; + + Pnam := TSS (Base_Type (U_Ent), TSS_Nam); + + -- If Pnam is present, it can be either inherited from an ancestor + -- type (in which case it is legal to redefine it for this type), or + -- be a previous definition of the attribute for the same type (in + -- which case it is illegal). + + -- In the first case, it will have been analyzed already, and we + -- can check that its profile does not match the expected profile + -- for a stream attribute of U_Ent. In the second case, either Pnam + -- has been analyzed (and has the expected profile), or it has not + -- been analyzed yet (case of a type that has not been frozen yet + -- and for which the stream attribute has been set using Set_TSS). + + if Present (Pnam) + and then (No (First_Entity (Pnam)) or else Has_Good_Profile (Pnam)) + then + Error_Msg_Sloc := Sloc (Pnam); + Error_Msg_Name_1 := Attr; + Error_Msg_N ("% attribute already defined #", Nam); + return; + end if; + + Analyze (Expr); + + if Is_Entity_Name (Expr) then + if not Is_Overloaded (Expr) then + if Has_Good_Profile (Entity (Expr)) then + Subp := Entity (Expr); + end if; + + else + Get_First_Interp (Expr, I, It); + while Present (It.Nam) loop + if Has_Good_Profile (It.Nam) then + Subp := It.Nam; + exit; + end if; + + Get_Next_Interp (I, It); + end loop; + end if; + end if; + + if Present (Subp) then + if Is_Abstract_Subprogram (Subp) then + Error_Msg_N ("stream subprogram must not be abstract", Expr); + return; + end if; + + Set_Entity (Expr, Subp); + Set_Etype (Expr, Etype (Subp)); + + New_Stream_Subprogram (N, U_Ent, Subp, TSS_Nam); + + else + Error_Msg_Name_1 := Attr; + Error_Msg_N ("incorrect expression for% attribute", Expr); + end if; + end Analyze_Stream_TSS_Definition; + + ---------------------- + -- Duplicate_Clause -- + ---------------------- + + function Duplicate_Clause return Boolean is + A : Node_Id; + + begin + -- Nothing to do if this attribute definition clause comes from + -- an aspect specification, since we could not be duplicating an + -- explicit clause, and we dealt with the case of duplicated aspects + -- in Analyze_Aspect_Specifications. + + if From_Aspect_Specification (N) then + return False; + end if; + + -- Otherwise current clause may duplicate previous clause or a + -- previously given aspect specification for the same aspect. + + A := Get_Rep_Item_For_Entity (U_Ent, Chars (N)); + + if Present (A) then + if Entity (A) = U_Ent then + Error_Msg_Name_1 := Chars (N); + Error_Msg_Sloc := Sloc (A); + Error_Msg_NE ("aspect% for & previously given#", N, U_Ent); + return True; + end if; + end if; + + return False; + end Duplicate_Clause; + + -- Start of processing for Analyze_Attribute_Definition_Clause + + begin + -- Process Ignore_Rep_Clauses option + + if Ignore_Rep_Clauses then + case Id is + + -- The following should be ignored. They do not affect legality + -- and may be target dependent. The basic idea of -gnatI is to + -- ignore any rep clauses that may be target dependent but do not + -- affect legality (except possibly to be rejected because they + -- are incompatible with the compilation target). + + when Attribute_Alignment | + Attribute_Bit_Order | + Attribute_Component_Size | + Attribute_Machine_Radix | + Attribute_Object_Size | + Attribute_Size | + Attribute_Small | + Attribute_Stream_Size | + Attribute_Value_Size => + + Rewrite (N, Make_Null_Statement (Sloc (N))); + return; + + -- The following should not be ignored, because in the first place + -- they are reasonably portable, and should not cause problems in + -- compiling code from another target, and also they do affect + -- legality, e.g. failing to provide a stream attribute for a + -- type may make a program illegal. + + when Attribute_External_Tag | + Attribute_Input | + Attribute_Output | + Attribute_Read | + Attribute_Storage_Pool | + Attribute_Storage_Size | + Attribute_Write => + null; + + -- Other cases are errors ("attribute& cannot be set with + -- definition clause"), which will be caught below. + + when others => + null; + end case; + end if; + + Analyze (Nam); + Ent := Entity (Nam); + + if Rep_Item_Too_Early (Ent, N) then + return; + end if; + + -- Rep clause applies to full view of incomplete type or private type if + -- we have one (if not, this is a premature use of the type). However, + -- certain semantic checks need to be done on the specified entity (i.e. + -- the private view), so we save it in Ent. + + if Is_Private_Type (Ent) + and then Is_Derived_Type (Ent) + and then not Is_Tagged_Type (Ent) + and then No (Full_View (Ent)) + then + -- If this is a private type whose completion is a derivation from + -- another private type, there is no full view, and the attribute + -- belongs to the type itself, not its underlying parent. + + U_Ent := Ent; + + elsif Ekind (Ent) = E_Incomplete_Type then + + -- The attribute applies to the full view, set the entity of the + -- attribute definition accordingly. + + Ent := Underlying_Type (Ent); + U_Ent := Ent; + Set_Entity (Nam, Ent); + + else + U_Ent := Underlying_Type (Ent); + end if; + + -- Complete other routine error checks + + if Etype (Nam) = Any_Type then + return; + + elsif Scope (Ent) /= Current_Scope then + Error_Msg_N ("entity must be declared in this scope", Nam); + return; + + elsif No (U_Ent) then + U_Ent := Ent; + + elsif Is_Type (U_Ent) + and then not Is_First_Subtype (U_Ent) + and then Id /= Attribute_Object_Size + and then Id /= Attribute_Value_Size + and then not From_At_Mod (N) + then + Error_Msg_N ("cannot specify attribute for subtype", Nam); + return; + end if; + + Set_Entity (N, U_Ent); + + -- Switch on particular attribute + + case Id is + + ------------- + -- Address -- + ------------- + + -- Address attribute definition clause + + when Attribute_Address => Address : begin + + -- A little error check, catch for X'Address use X'Address; + + if Nkind (Nam) = N_Identifier + and then Nkind (Expr) = N_Attribute_Reference + and then Attribute_Name (Expr) = Name_Address + and then Nkind (Prefix (Expr)) = N_Identifier + and then Chars (Nam) = Chars (Prefix (Expr)) + then + Error_Msg_NE + ("address for & is self-referencing", Prefix (Expr), Ent); + return; + end if; + + -- Not that special case, carry on with analysis of expression + + Analyze_And_Resolve (Expr, RTE (RE_Address)); + + -- Even when ignoring rep clauses we need to indicate that the + -- entity has an address clause and thus it is legal to declare + -- it imported. + + if Ignore_Rep_Clauses then + if Ekind_In (U_Ent, E_Variable, E_Constant) then + Record_Rep_Item (U_Ent, N); + end if; + + return; + end if; + + if Duplicate_Clause then + null; + + -- Case of address clause for subprogram + + elsif Is_Subprogram (U_Ent) then + if Has_Homonym (U_Ent) then + Error_Msg_N + ("address clause cannot be given " & + "for overloaded subprogram", + Nam); + return; + end if; + + -- For subprograms, all address clauses are permitted, and we + -- mark the subprogram as having a deferred freeze so that Gigi + -- will not elaborate it too soon. + + -- Above needs more comments, what is too soon about??? + + Set_Has_Delayed_Freeze (U_Ent); + + -- Case of address clause for entry + + elsif Ekind (U_Ent) = E_Entry then + if Nkind (Parent (N)) = N_Task_Body then + Error_Msg_N + ("entry address must be specified in task spec", Nam); + return; + end if; + + -- For entries, we require a constant address + + Check_Constant_Address_Clause (Expr, U_Ent); + + -- Special checks for task types + + if Is_Task_Type (Scope (U_Ent)) + and then Comes_From_Source (Scope (U_Ent)) + then + Error_Msg_N + ("?entry address declared for entry in task type", N); + Error_Msg_N + ("\?only one task can be declared of this type", N); + end if; + + -- Entry address clauses are obsolescent + + Check_Restriction (No_Obsolescent_Features, N); + + if Warn_On_Obsolescent_Feature then + Error_Msg_N + ("attaching interrupt to task entry is an " & + "obsolescent feature (RM J.7.1)?", N); + Error_Msg_N + ("\use interrupt procedure instead?", N); + end if; + + -- Case of an address clause for a controlled object which we + -- consider to be erroneous. + + elsif Is_Controlled (Etype (U_Ent)) + or else Has_Controlled_Component (Etype (U_Ent)) + then + Error_Msg_NE + ("?controlled object& must not be overlaid", Nam, U_Ent); + Error_Msg_N + ("\?Program_Error will be raised at run time", Nam); + Insert_Action (Declaration_Node (U_Ent), + Make_Raise_Program_Error (Loc, + Reason => PE_Overlaid_Controlled_Object)); + return; + + -- Case of address clause for a (non-controlled) object + + elsif + Ekind (U_Ent) = E_Variable + or else + Ekind (U_Ent) = E_Constant + then + declare + Expr : constant Node_Id := Expression (N); + O_Ent : Entity_Id; + Off : Boolean; + + begin + -- Exported variables cannot have an address clause, because + -- this cancels the effect of the pragma Export. + + if Is_Exported (U_Ent) then + Error_Msg_N + ("cannot export object with address clause", Nam); + return; + end if; + + Find_Overlaid_Entity (N, O_Ent, Off); + + -- Overlaying controlled objects is erroneous + + if Present (O_Ent) + and then (Has_Controlled_Component (Etype (O_Ent)) + or else Is_Controlled (Etype (O_Ent))) + then + Error_Msg_N + ("?cannot overlay with controlled object", Expr); + Error_Msg_N + ("\?Program_Error will be raised at run time", Expr); + Insert_Action (Declaration_Node (U_Ent), + Make_Raise_Program_Error (Loc, + Reason => PE_Overlaid_Controlled_Object)); + return; + + elsif Present (O_Ent) + and then Ekind (U_Ent) = E_Constant + and then not Is_Constant_Object (O_Ent) + then + Error_Msg_N ("constant overlays a variable?", Expr); + + elsif Present (Renamed_Object (U_Ent)) then + Error_Msg_N + ("address clause not allowed" + & " for a renaming declaration (RM 13.1(6))", Nam); + return; + + -- Imported variables can have an address clause, but then + -- the import is pretty meaningless except to suppress + -- initializations, so we do not need such variables to + -- be statically allocated (and in fact it causes trouble + -- if the address clause is a local value). + + elsif Is_Imported (U_Ent) then + Set_Is_Statically_Allocated (U_Ent, False); + end if; + + -- We mark a possible modification of a variable with an + -- address clause, since it is likely aliasing is occurring. + + Note_Possible_Modification (Nam, Sure => False); + + -- Here we are checking for explicit overlap of one variable + -- by another, and if we find this then mark the overlapped + -- variable as also being volatile to prevent unwanted + -- optimizations. This is a significant pessimization so + -- avoid it when there is an offset, i.e. when the object + -- is composite; they cannot be optimized easily anyway. + + if Present (O_Ent) + and then Is_Object (O_Ent) + and then not Off + then + Set_Treat_As_Volatile (O_Ent); + end if; + + -- Legality checks on the address clause for initialized + -- objects is deferred until the freeze point, because + -- a subsequent pragma might indicate that the object is + -- imported and thus not initialized. + + Set_Has_Delayed_Freeze (U_Ent); + + -- If an initialization call has been generated for this + -- object, it needs to be deferred to after the freeze node + -- we have just now added, otherwise GIGI will see a + -- reference to the variable (as actual to the IP call) + -- before its definition. + + declare + Init_Call : constant Node_Id := Find_Init_Call (U_Ent, N); + begin + if Present (Init_Call) then + Remove (Init_Call); + Append_Freeze_Action (U_Ent, Init_Call); + end if; + end; + + if Is_Exported (U_Ent) then + Error_Msg_N + ("& cannot be exported if an address clause is given", + Nam); + Error_Msg_N + ("\define and export a variable " & + "that holds its address instead", + Nam); + end if; + + -- Entity has delayed freeze, so we will generate an + -- alignment check at the freeze point unless suppressed. + + if not Range_Checks_Suppressed (U_Ent) + and then not Alignment_Checks_Suppressed (U_Ent) + then + Set_Check_Address_Alignment (N); + end if; + + -- Kill the size check code, since we are not allocating + -- the variable, it is somewhere else. + + Kill_Size_Check_Code (U_Ent); + + -- If the address clause is of the form: + + -- for Y'Address use X'Address + + -- or + + -- Const : constant Address := X'Address; + -- ... + -- for Y'Address use Const; + + -- then we make an entry in the table for checking the size + -- and alignment of the overlaying variable. We defer this + -- check till after code generation to take full advantage + -- of the annotation done by the back end. This entry is + -- only made if the address clause comes from source. + -- If the entity has a generic type, the check will be + -- performed in the instance if the actual type justifies + -- it, and we do not insert the clause in the table to + -- prevent spurious warnings. + + if Address_Clause_Overlay_Warnings + and then Comes_From_Source (N) + and then Present (O_Ent) + and then Is_Object (O_Ent) + then + if not Is_Generic_Type (Etype (U_Ent)) then + Address_Clause_Checks.Append ((N, U_Ent, O_Ent, Off)); + end if; + + -- If variable overlays a constant view, and we are + -- warning on overlays, then mark the variable as + -- overlaying a constant (we will give warnings later + -- if this variable is assigned). + + if Is_Constant_Object (O_Ent) + and then Ekind (U_Ent) = E_Variable + then + Set_Overlays_Constant (U_Ent); + end if; + end if; + end; + + -- Not a valid entity for an address clause + + else + Error_Msg_N ("address cannot be given for &", Nam); + end if; + end Address; + + --------------- + -- Alignment -- + --------------- + + -- Alignment attribute definition clause + + when Attribute_Alignment => Alignment : declare + Align : constant Uint := Get_Alignment_Value (Expr); + + begin + FOnly := True; + + if not Is_Type (U_Ent) + and then Ekind (U_Ent) /= E_Variable + and then Ekind (U_Ent) /= E_Constant + then + Error_Msg_N ("alignment cannot be given for &", Nam); + + elsif Duplicate_Clause then + null; + + elsif Align /= No_Uint then + Set_Has_Alignment_Clause (U_Ent); + Set_Alignment (U_Ent, Align); + + -- For an array type, U_Ent is the first subtype. In that case, + -- also set the alignment of the anonymous base type so that + -- other subtypes (such as the itypes for aggregates of the + -- type) also receive the expected alignment. + + if Is_Array_Type (U_Ent) then + Set_Alignment (Base_Type (U_Ent), Align); + end if; + end if; + end Alignment; + + --------------- + -- Bit_Order -- + --------------- + + -- Bit_Order attribute definition clause + + when Attribute_Bit_Order => Bit_Order : declare + begin + if not Is_Record_Type (U_Ent) then + Error_Msg_N + ("Bit_Order can only be defined for record type", Nam); + + elsif Duplicate_Clause then + null; + + else + Analyze_And_Resolve (Expr, RTE (RE_Bit_Order)); + + if Etype (Expr) = Any_Type then + return; + + elsif not Is_Static_Expression (Expr) then + Flag_Non_Static_Expr + ("Bit_Order requires static expression!", Expr); + + else + if (Expr_Value (Expr) = 0) /= Bytes_Big_Endian then + Set_Reverse_Bit_Order (U_Ent, True); + end if; + end if; + end if; + end Bit_Order; + + -------------------- + -- Component_Size -- + -------------------- + + -- Component_Size attribute definition clause + + when Attribute_Component_Size => Component_Size_Case : declare + Csize : constant Uint := Static_Integer (Expr); + Ctyp : Entity_Id; + Btype : Entity_Id; + Biased : Boolean; + New_Ctyp : Entity_Id; + Decl : Node_Id; + + begin + if not Is_Array_Type (U_Ent) then + Error_Msg_N ("component size requires array type", Nam); + return; + end if; + + Btype := Base_Type (U_Ent); + Ctyp := Component_Type (Btype); + + if Duplicate_Clause then + null; + + elsif Rep_Item_Too_Early (Btype, N) then + null; + + elsif Csize /= No_Uint then + Check_Size (Expr, Ctyp, Csize, Biased); + + -- For the biased case, build a declaration for a subtype that + -- will be used to represent the biased subtype that reflects + -- the biased representation of components. We need the subtype + -- to get proper conversions on referencing elements of the + -- array. Note: component size clauses are ignored in VM mode. + + if VM_Target = No_VM then + if Biased then + New_Ctyp := + Make_Defining_Identifier (Loc, + Chars => + New_External_Name (Chars (U_Ent), 'C', 0, 'T')); + + Decl := + Make_Subtype_Declaration (Loc, + Defining_Identifier => New_Ctyp, + Subtype_Indication => + New_Occurrence_Of (Component_Type (Btype), Loc)); + + Set_Parent (Decl, N); + Analyze (Decl, Suppress => All_Checks); + + Set_Has_Delayed_Freeze (New_Ctyp, False); + Set_Esize (New_Ctyp, Csize); + Set_RM_Size (New_Ctyp, Csize); + Init_Alignment (New_Ctyp); + Set_Is_Itype (New_Ctyp, True); + Set_Associated_Node_For_Itype (New_Ctyp, U_Ent); + + Set_Component_Type (Btype, New_Ctyp); + Set_Biased (New_Ctyp, N, "component size clause"); + end if; + + Set_Component_Size (Btype, Csize); + + -- For VM case, we ignore component size clauses + + else + -- Give a warning unless we are in GNAT mode, in which case + -- the warning is suppressed since it is not useful. + + if not GNAT_Mode then + Error_Msg_N + ("?component size ignored in this configuration", N); + end if; + end if; + + -- Deal with warning on overridden size + + if Warn_On_Overridden_Size + and then Has_Size_Clause (Ctyp) + and then RM_Size (Ctyp) /= Csize + then + Error_Msg_NE + ("?component size overrides size clause for&", + N, Ctyp); + end if; + + Set_Has_Component_Size_Clause (Btype, True); + Set_Has_Non_Standard_Rep (Btype, True); + end if; + end Component_Size_Case; + + ------------------ + -- External_Tag -- + ------------------ + + when Attribute_External_Tag => External_Tag : + begin + if not Is_Tagged_Type (U_Ent) then + Error_Msg_N ("should be a tagged type", Nam); + end if; + + if Duplicate_Clause then + null; + + else + Analyze_And_Resolve (Expr, Standard_String); + + if not Is_Static_Expression (Expr) then + Flag_Non_Static_Expr + ("static string required for tag name!", Nam); + end if; + + if VM_Target = No_VM then + Set_Has_External_Tag_Rep_Clause (U_Ent); + else + Error_Msg_Name_1 := Attr; + Error_Msg_N + ("% attribute unsupported in this configuration", Nam); + end if; + + if not Is_Library_Level_Entity (U_Ent) then + Error_Msg_NE + ("?non-unique external tag supplied for &", N, U_Ent); + Error_Msg_N + ("?\same external tag applies to all subprogram calls", N); + Error_Msg_N + ("?\corresponding internal tag cannot be obtained", N); + end if; + end if; + end External_Tag; + + ----------- + -- Input -- + ----------- + + when Attribute_Input => + Analyze_Stream_TSS_Definition (TSS_Stream_Input); + Set_Has_Specified_Stream_Input (Ent); + + ------------------- + -- Machine_Radix -- + ------------------- + + -- Machine radix attribute definition clause + + when Attribute_Machine_Radix => Machine_Radix : declare + Radix : constant Uint := Static_Integer (Expr); + + begin + if not Is_Decimal_Fixed_Point_Type (U_Ent) then + Error_Msg_N ("decimal fixed-point type expected for &", Nam); + + elsif Duplicate_Clause then + null; + + elsif Radix /= No_Uint then + Set_Has_Machine_Radix_Clause (U_Ent); + Set_Has_Non_Standard_Rep (Base_Type (U_Ent)); + + if Radix = 2 then + null; + elsif Radix = 10 then + Set_Machine_Radix_10 (U_Ent); + else + Error_Msg_N ("machine radix value must be 2 or 10", Expr); + end if; + end if; + end Machine_Radix; + + ----------------- + -- Object_Size -- + ----------------- + + -- Object_Size attribute definition clause + + when Attribute_Object_Size => Object_Size : declare + Size : constant Uint := Static_Integer (Expr); + + Biased : Boolean; + pragma Warnings (Off, Biased); + + begin + if not Is_Type (U_Ent) then + Error_Msg_N ("Object_Size cannot be given for &", Nam); + + elsif Duplicate_Clause then + null; + + else + Check_Size (Expr, U_Ent, Size, Biased); + + if Size /= 8 + and then + Size /= 16 + and then + Size /= 32 + and then + UI_Mod (Size, 64) /= 0 + then + Error_Msg_N + ("Object_Size must be 8, 16, 32, or multiple of 64", + Expr); + end if; + + Set_Esize (U_Ent, Size); + Set_Has_Object_Size_Clause (U_Ent); + Alignment_Check_For_Esize_Change (U_Ent); + end if; + end Object_Size; + + ------------ + -- Output -- + ------------ + + when Attribute_Output => + Analyze_Stream_TSS_Definition (TSS_Stream_Output); + Set_Has_Specified_Stream_Output (Ent); + + ---------- + -- Read -- + ---------- + + when Attribute_Read => + Analyze_Stream_TSS_Definition (TSS_Stream_Read); + Set_Has_Specified_Stream_Read (Ent); + + ---------- + -- Size -- + ---------- + + -- Size attribute definition clause + + when Attribute_Size => Size : declare + Size : constant Uint := Static_Integer (Expr); + Etyp : Entity_Id; + Biased : Boolean; + + begin + FOnly := True; + + if Duplicate_Clause then + null; + + elsif not Is_Type (U_Ent) + and then Ekind (U_Ent) /= E_Variable + and then Ekind (U_Ent) /= E_Constant + then + Error_Msg_N ("size cannot be given for &", Nam); + + elsif Is_Array_Type (U_Ent) + and then not Is_Constrained (U_Ent) + then + Error_Msg_N + ("size cannot be given for unconstrained array", Nam); + + elsif Size /= No_Uint then + + if VM_Target /= No_VM and then not GNAT_Mode then + + -- Size clause is not handled properly on VM targets. + -- Display a warning unless we are in GNAT mode, in which + -- case this is useless. + + Error_Msg_N + ("?size clauses are ignored in this configuration", N); + end if; + + if Is_Type (U_Ent) then + Etyp := U_Ent; + else + Etyp := Etype (U_Ent); + end if; + + -- Check size, note that Gigi is in charge of checking that the + -- size of an array or record type is OK. Also we do not check + -- the size in the ordinary fixed-point case, since it is too + -- early to do so (there may be subsequent small clause that + -- affects the size). We can check the size if a small clause + -- has already been given. + + if not Is_Ordinary_Fixed_Point_Type (U_Ent) + or else Has_Small_Clause (U_Ent) + then + Check_Size (Expr, Etyp, Size, Biased); + Set_Biased (U_Ent, N, "size clause", Biased); + end if; + + -- For types set RM_Size and Esize if possible + + if Is_Type (U_Ent) then + Set_RM_Size (U_Ent, Size); + + -- For scalar types, increase Object_Size to power of 2, but + -- not less than a storage unit in any case (i.e., normally + -- this means it will be byte addressable). + + if Is_Scalar_Type (U_Ent) then + if Size <= System_Storage_Unit then + Init_Esize (U_Ent, System_Storage_Unit); + elsif Size <= 16 then + Init_Esize (U_Ent, 16); + elsif Size <= 32 then + Init_Esize (U_Ent, 32); + else + Set_Esize (U_Ent, (Size + 63) / 64 * 64); + end if; + + -- For all other types, object size = value size. The + -- backend will adjust as needed. + + else + Set_Esize (U_Ent, Size); + end if; + + Alignment_Check_For_Esize_Change (U_Ent); + + -- For objects, set Esize only + + else + if Is_Elementary_Type (Etyp) then + if Size /= System_Storage_Unit + and then + Size /= System_Storage_Unit * 2 + and then + Size /= System_Storage_Unit * 4 + and then + Size /= System_Storage_Unit * 8 + then + Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit); + Error_Msg_Uint_2 := Error_Msg_Uint_1 * 8; + Error_Msg_N + ("size for primitive object must be a power of 2" + & " in the range ^-^", N); + end if; + end if; + + Set_Esize (U_Ent, Size); + end if; + + Set_Has_Size_Clause (U_Ent); + end if; + end Size; + + ----------- + -- Small -- + ----------- + + -- Small attribute definition clause + + when Attribute_Small => Small : declare + Implicit_Base : constant Entity_Id := Base_Type (U_Ent); + Small : Ureal; + + begin + Analyze_And_Resolve (Expr, Any_Real); + + if Etype (Expr) = Any_Type then + return; + + elsif not Is_Static_Expression (Expr) then + Flag_Non_Static_Expr + ("small requires static expression!", Expr); + return; + + else + Small := Expr_Value_R (Expr); + + if Small <= Ureal_0 then + Error_Msg_N ("small value must be greater than zero", Expr); + return; + end if; + + end if; + + if not Is_Ordinary_Fixed_Point_Type (U_Ent) then + Error_Msg_N + ("small requires an ordinary fixed point type", Nam); + + elsif Has_Small_Clause (U_Ent) then + Error_Msg_N ("small already given for &", Nam); + + elsif Small > Delta_Value (U_Ent) then + Error_Msg_N + ("small value must not be greater then delta value", Nam); + + else + Set_Small_Value (U_Ent, Small); + Set_Small_Value (Implicit_Base, Small); + Set_Has_Small_Clause (U_Ent); + Set_Has_Small_Clause (Implicit_Base); + Set_Has_Non_Standard_Rep (Implicit_Base); + end if; + end Small; + + ------------------ + -- Storage_Pool -- + ------------------ + + -- Storage_Pool attribute definition clause + + when Attribute_Storage_Pool => Storage_Pool : declare + Pool : Entity_Id; + T : Entity_Id; + + begin + if Ekind (U_Ent) = E_Access_Subprogram_Type then + Error_Msg_N + ("storage pool cannot be given for access-to-subprogram type", + Nam); + return; + + elsif not + Ekind_In (U_Ent, E_Access_Type, E_General_Access_Type) + then + Error_Msg_N + ("storage pool can only be given for access types", Nam); + return; + + elsif Is_Derived_Type (U_Ent) then + Error_Msg_N + ("storage pool cannot be given for a derived access type", + Nam); + + elsif Duplicate_Clause then + return; + + elsif Present (Associated_Storage_Pool (U_Ent)) then + Error_Msg_N ("storage pool already given for &", Nam); + return; + end if; + + Analyze_And_Resolve + (Expr, Class_Wide_Type (RTE (RE_Root_Storage_Pool))); + + if not Denotes_Variable (Expr) then + Error_Msg_N ("storage pool must be a variable", Expr); + return; + end if; + + if Nkind (Expr) = N_Type_Conversion then + T := Etype (Expression (Expr)); + else + T := Etype (Expr); + end if; + + -- The Stack_Bounded_Pool is used internally for implementing + -- access types with a Storage_Size. Since it only work + -- properly when used on one specific type, we need to check + -- that it is not hijacked improperly: + -- type T is access Integer; + -- for T'Storage_Size use n; + -- type Q is access Float; + -- for Q'Storage_Size use T'Storage_Size; -- incorrect + + if RTE_Available (RE_Stack_Bounded_Pool) + and then Base_Type (T) = RTE (RE_Stack_Bounded_Pool) + then + Error_Msg_N ("non-shareable internal Pool", Expr); + return; + end if; + + -- If the argument is a name that is not an entity name, then + -- we construct a renaming operation to define an entity of + -- type storage pool. + + if not Is_Entity_Name (Expr) + and then Is_Object_Reference (Expr) + then + Pool := Make_Temporary (Loc, 'P', Expr); + + declare + Rnode : constant Node_Id := + Make_Object_Renaming_Declaration (Loc, + Defining_Identifier => Pool, + Subtype_Mark => + New_Occurrence_Of (Etype (Expr), Loc), + Name => Expr); + + begin + Insert_Before (N, Rnode); + Analyze (Rnode); + Set_Associated_Storage_Pool (U_Ent, Pool); + end; + + elsif Is_Entity_Name (Expr) then + Pool := Entity (Expr); + + -- If pool is a renamed object, get original one. This can + -- happen with an explicit renaming, and within instances. + + while Present (Renamed_Object (Pool)) + and then Is_Entity_Name (Renamed_Object (Pool)) + loop + Pool := Entity (Renamed_Object (Pool)); + end loop; + + if Present (Renamed_Object (Pool)) + and then Nkind (Renamed_Object (Pool)) = N_Type_Conversion + and then Is_Entity_Name (Expression (Renamed_Object (Pool))) + then + Pool := Entity (Expression (Renamed_Object (Pool))); + end if; + + Set_Associated_Storage_Pool (U_Ent, Pool); + + elsif Nkind (Expr) = N_Type_Conversion + and then Is_Entity_Name (Expression (Expr)) + and then Nkind (Original_Node (Expr)) = N_Attribute_Reference + then + Pool := Entity (Expression (Expr)); + Set_Associated_Storage_Pool (U_Ent, Pool); + + else + Error_Msg_N ("incorrect reference to a Storage Pool", Expr); + return; + end if; + end Storage_Pool; + + ------------------ + -- Storage_Size -- + ------------------ + + -- Storage_Size attribute definition clause + + when Attribute_Storage_Size => Storage_Size : declare + Btype : constant Entity_Id := Base_Type (U_Ent); + Sprag : Node_Id; + + begin + if Is_Task_Type (U_Ent) then + Check_Restriction (No_Obsolescent_Features, N); + + if Warn_On_Obsolescent_Feature then + Error_Msg_N + ("storage size clause for task is an " & + "obsolescent feature (RM J.9)?", N); + Error_Msg_N ("\use Storage_Size pragma instead?", N); + end if; + + FOnly := True; + end if; + + if not Is_Access_Type (U_Ent) + and then Ekind (U_Ent) /= E_Task_Type + then + Error_Msg_N ("storage size cannot be given for &", Nam); + + elsif Is_Access_Type (U_Ent) and Is_Derived_Type (U_Ent) then + Error_Msg_N + ("storage size cannot be given for a derived access type", + Nam); + + elsif Duplicate_Clause then + null; + + else + Analyze_And_Resolve (Expr, Any_Integer); + + if Is_Access_Type (U_Ent) then + if Present (Associated_Storage_Pool (U_Ent)) then + Error_Msg_N ("storage pool already given for &", Nam); + return; + end if; + + if Is_OK_Static_Expression (Expr) + and then Expr_Value (Expr) = 0 + then + Set_No_Pool_Assigned (Btype); + end if; + + else -- Is_Task_Type (U_Ent) + Sprag := Get_Rep_Pragma (Btype, Name_Storage_Size); + + if Present (Sprag) then + Error_Msg_Sloc := Sloc (Sprag); + Error_Msg_N + ("Storage_Size already specified#", Nam); + return; + end if; + end if; + + Set_Has_Storage_Size_Clause (Btype); + end if; + end Storage_Size; + + ----------------- + -- Stream_Size -- + ----------------- + + when Attribute_Stream_Size => Stream_Size : declare + Size : constant Uint := Static_Integer (Expr); + + begin + if Ada_Version <= Ada_95 then + Check_Restriction (No_Implementation_Attributes, N); + end if; + + if Duplicate_Clause then + null; + + elsif Is_Elementary_Type (U_Ent) then + if Size /= System_Storage_Unit + and then + Size /= System_Storage_Unit * 2 + and then + Size /= System_Storage_Unit * 4 + and then + Size /= System_Storage_Unit * 8 + then + Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit); + Error_Msg_N + ("stream size for elementary type must be a" + & " power of 2 and at least ^", N); + + elsif RM_Size (U_Ent) > Size then + Error_Msg_Uint_1 := RM_Size (U_Ent); + Error_Msg_N + ("stream size for elementary type must be a" + & " power of 2 and at least ^", N); + end if; + + Set_Has_Stream_Size_Clause (U_Ent); + + else + Error_Msg_N ("Stream_Size cannot be given for &", Nam); + end if; + end Stream_Size; + + ---------------- + -- Value_Size -- + ---------------- + + -- Value_Size attribute definition clause + + when Attribute_Value_Size => Value_Size : declare + Size : constant Uint := Static_Integer (Expr); + Biased : Boolean; + + begin + if not Is_Type (U_Ent) then + Error_Msg_N ("Value_Size cannot be given for &", Nam); + + elsif Duplicate_Clause then + null; + + elsif Is_Array_Type (U_Ent) + and then not Is_Constrained (U_Ent) + then + Error_Msg_N + ("Value_Size cannot be given for unconstrained array", Nam); + + else + if Is_Elementary_Type (U_Ent) then + Check_Size (Expr, U_Ent, Size, Biased); + Set_Biased (U_Ent, N, "value size clause", Biased); + end if; + + Set_RM_Size (U_Ent, Size); + end if; + end Value_Size; + + ----------- + -- Write -- + ----------- + + when Attribute_Write => + Analyze_Stream_TSS_Definition (TSS_Stream_Write); + Set_Has_Specified_Stream_Write (Ent); + + -- All other attributes cannot be set + + when others => + Error_Msg_N + ("attribute& cannot be set with definition clause", N); + end case; + + -- The test for the type being frozen must be performed after + -- any expression the clause has been analyzed since the expression + -- itself might cause freezing that makes the clause illegal. + + if Rep_Item_Too_Late (U_Ent, N, FOnly) then + return; + end if; + end Analyze_Attribute_Definition_Clause; + + ---------------------------- + -- Analyze_Code_Statement -- + ---------------------------- + + procedure Analyze_Code_Statement (N : Node_Id) is + HSS : constant Node_Id := Parent (N); + SBody : constant Node_Id := Parent (HSS); + Subp : constant Entity_Id := Current_Scope; + Stmt : Node_Id; + Decl : Node_Id; + StmtO : Node_Id; + DeclO : Node_Id; + + begin + -- Analyze and check we get right type, note that this implements the + -- requirement (RM 13.8(1)) that Machine_Code be with'ed, since that + -- is the only way that Asm_Insn could possibly be visible. + + Analyze_And_Resolve (Expression (N)); + + if Etype (Expression (N)) = Any_Type then + return; + elsif Etype (Expression (N)) /= RTE (RE_Asm_Insn) then + Error_Msg_N ("incorrect type for code statement", N); + return; + end if; + + Check_Code_Statement (N); + + -- Make sure we appear in the handled statement sequence of a + -- subprogram (RM 13.8(3)). + + if Nkind (HSS) /= N_Handled_Sequence_Of_Statements + or else Nkind (SBody) /= N_Subprogram_Body + then + Error_Msg_N + ("code statement can only appear in body of subprogram", N); + return; + end if; + + -- Do remaining checks (RM 13.8(3)) if not already done + + if not Is_Machine_Code_Subprogram (Subp) then + Set_Is_Machine_Code_Subprogram (Subp); + + -- No exception handlers allowed + + if Present (Exception_Handlers (HSS)) then + Error_Msg_N + ("exception handlers not permitted in machine code subprogram", + First (Exception_Handlers (HSS))); + end if; + + -- No declarations other than use clauses and pragmas (we allow + -- certain internally generated declarations as well). + + Decl := First (Declarations (SBody)); + while Present (Decl) loop + DeclO := Original_Node (Decl); + if Comes_From_Source (DeclO) + and not Nkind_In (DeclO, N_Pragma, + N_Use_Package_Clause, + N_Use_Type_Clause, + N_Implicit_Label_Declaration) + then + Error_Msg_N + ("this declaration not allowed in machine code subprogram", + DeclO); + end if; + + Next (Decl); + end loop; + + -- No statements other than code statements, pragmas, and labels. + -- Again we allow certain internally generated statements. + + Stmt := First (Statements (HSS)); + while Present (Stmt) loop + StmtO := Original_Node (Stmt); + if Comes_From_Source (StmtO) + and then not Nkind_In (StmtO, N_Pragma, + N_Label, + N_Code_Statement) + then + Error_Msg_N + ("this statement is not allowed in machine code subprogram", + StmtO); + end if; + + Next (Stmt); + end loop; + end if; + end Analyze_Code_Statement; + + ----------------------------------------------- + -- Analyze_Enumeration_Representation_Clause -- + ----------------------------------------------- + + procedure Analyze_Enumeration_Representation_Clause (N : Node_Id) is + Ident : constant Node_Id := Identifier (N); + Aggr : constant Node_Id := Array_Aggregate (N); + Enumtype : Entity_Id; + Elit : Entity_Id; + Expr : Node_Id; + Assoc : Node_Id; + Choice : Node_Id; + Val : Uint; + Err : Boolean := False; + + Lo : constant Uint := Expr_Value (Type_Low_Bound (Universal_Integer)); + Hi : constant Uint := Expr_Value (Type_High_Bound (Universal_Integer)); + -- Allowed range of universal integer (= allowed range of enum lit vals) + + Min : Uint; + Max : Uint; + -- Minimum and maximum values of entries + + Max_Node : Node_Id; + -- Pointer to node for literal providing max value + + begin + if Ignore_Rep_Clauses then + return; + end if; + + -- First some basic error checks + + Find_Type (Ident); + Enumtype := Entity (Ident); + + if Enumtype = Any_Type + or else Rep_Item_Too_Early (Enumtype, N) + then + return; + else + Enumtype := Underlying_Type (Enumtype); + end if; + + if not Is_Enumeration_Type (Enumtype) then + Error_Msg_NE + ("enumeration type required, found}", + Ident, First_Subtype (Enumtype)); + return; + end if; + + -- Ignore rep clause on generic actual type. This will already have + -- been flagged on the template as an error, and this is the safest + -- way to ensure we don't get a junk cascaded message in the instance. + + if Is_Generic_Actual_Type (Enumtype) then + return; + + -- Type must be in current scope + + elsif Scope (Enumtype) /= Current_Scope then + Error_Msg_N ("type must be declared in this scope", Ident); + return; + + -- Type must be a first subtype + + elsif not Is_First_Subtype (Enumtype) then + Error_Msg_N ("cannot give enumeration rep clause for subtype", N); + return; + + -- Ignore duplicate rep clause + + elsif Has_Enumeration_Rep_Clause (Enumtype) then + Error_Msg_N ("duplicate enumeration rep clause ignored", N); + return; + + -- Don't allow rep clause for standard [wide_[wide_]]character + + elsif Is_Standard_Character_Type (Enumtype) then + Error_Msg_N ("enumeration rep clause not allowed for this type", N); + return; + + -- Check that the expression is a proper aggregate (no parentheses) + + elsif Paren_Count (Aggr) /= 0 then + Error_Msg + ("extra parentheses surrounding aggregate not allowed", + First_Sloc (Aggr)); + return; + + -- All tests passed, so set rep clause in place + + else + Set_Has_Enumeration_Rep_Clause (Enumtype); + Set_Has_Enumeration_Rep_Clause (Base_Type (Enumtype)); + end if; + + -- Now we process the aggregate. Note that we don't use the normal + -- aggregate code for this purpose, because we don't want any of the + -- normal expansion activities, and a number of special semantic + -- rules apply (including the component type being any integer type) + + Elit := First_Literal (Enumtype); + + -- First the positional entries if any + + if Present (Expressions (Aggr)) then + Expr := First (Expressions (Aggr)); + while Present (Expr) loop + if No (Elit) then + Error_Msg_N ("too many entries in aggregate", Expr); + return; + end if; + + Val := Static_Integer (Expr); + + -- Err signals that we found some incorrect entries processing + -- the list. The final checks for completeness and ordering are + -- skipped in this case. + + if Val = No_Uint then + Err := True; + elsif Val < Lo or else Hi < Val then + Error_Msg_N ("value outside permitted range", Expr); + Err := True; + end if; + + Set_Enumeration_Rep (Elit, Val); + Set_Enumeration_Rep_Expr (Elit, Expr); + Next (Expr); + Next (Elit); + end loop; + end if; + + -- Now process the named entries if present + + if Present (Component_Associations (Aggr)) then + Assoc := First (Component_Associations (Aggr)); + while Present (Assoc) loop + Choice := First (Choices (Assoc)); + + if Present (Next (Choice)) then + Error_Msg_N + ("multiple choice not allowed here", Next (Choice)); + Err := True; + end if; + + if Nkind (Choice) = N_Others_Choice then + Error_Msg_N ("others choice not allowed here", Choice); + Err := True; + + elsif Nkind (Choice) = N_Range then + -- ??? should allow zero/one element range here + Error_Msg_N ("range not allowed here", Choice); + Err := True; + + else + Analyze_And_Resolve (Choice, Enumtype); + + if Is_Entity_Name (Choice) + and then Is_Type (Entity (Choice)) + then + Error_Msg_N ("subtype name not allowed here", Choice); + Err := True; + -- ??? should allow static subtype with zero/one entry + + elsif Etype (Choice) = Base_Type (Enumtype) then + if not Is_Static_Expression (Choice) then + Flag_Non_Static_Expr + ("non-static expression used for choice!", Choice); + Err := True; + + else + Elit := Expr_Value_E (Choice); + + if Present (Enumeration_Rep_Expr (Elit)) then + Error_Msg_Sloc := Sloc (Enumeration_Rep_Expr (Elit)); + Error_Msg_NE + ("representation for& previously given#", + Choice, Elit); + Err := True; + end if; + + Set_Enumeration_Rep_Expr (Elit, Expression (Assoc)); + + Expr := Expression (Assoc); + Val := Static_Integer (Expr); + + if Val = No_Uint then + Err := True; + + elsif Val < Lo or else Hi < Val then + Error_Msg_N ("value outside permitted range", Expr); + Err := True; + end if; + + Set_Enumeration_Rep (Elit, Val); + end if; + end if; + end if; + + Next (Assoc); + end loop; + end if; + + -- Aggregate is fully processed. Now we check that a full set of + -- representations was given, and that they are in range and in order. + -- These checks are only done if no other errors occurred. + + if not Err then + Min := No_Uint; + Max := No_Uint; + + Elit := First_Literal (Enumtype); + while Present (Elit) loop + if No (Enumeration_Rep_Expr (Elit)) then + Error_Msg_NE ("missing representation for&!", N, Elit); + + else + Val := Enumeration_Rep (Elit); + + if Min = No_Uint then + Min := Val; + end if; + + if Val /= No_Uint then + if Max /= No_Uint and then Val <= Max then + Error_Msg_NE + ("enumeration value for& not ordered!", + Enumeration_Rep_Expr (Elit), Elit); + end if; + + Max_Node := Enumeration_Rep_Expr (Elit); + Max := Val; + end if; + + -- If there is at least one literal whose representation is not + -- equal to the Pos value, then note that this enumeration type + -- has a non-standard representation. + + if Val /= Enumeration_Pos (Elit) then + Set_Has_Non_Standard_Rep (Base_Type (Enumtype)); + end if; + end if; + + Next (Elit); + end loop; + + -- Now set proper size information + + declare + Minsize : Uint := UI_From_Int (Minimum_Size (Enumtype)); + + begin + if Has_Size_Clause (Enumtype) then + + -- All OK, if size is OK now + + if RM_Size (Enumtype) >= Minsize then + null; + + else + -- Try if we can get by with biasing + + Minsize := + UI_From_Int (Minimum_Size (Enumtype, Biased => True)); + + -- Error message if even biasing does not work + + if RM_Size (Enumtype) < Minsize then + Error_Msg_Uint_1 := RM_Size (Enumtype); + Error_Msg_Uint_2 := Max; + Error_Msg_N + ("previously given size (^) is too small " + & "for this value (^)", Max_Node); + + -- If biasing worked, indicate that we now have biased rep + + else + Set_Biased + (Enumtype, Size_Clause (Enumtype), "size clause"); + end if; + end if; + + else + Set_RM_Size (Enumtype, Minsize); + Set_Enum_Esize (Enumtype); + end if; + + Set_RM_Size (Base_Type (Enumtype), RM_Size (Enumtype)); + Set_Esize (Base_Type (Enumtype), Esize (Enumtype)); + Set_Alignment (Base_Type (Enumtype), Alignment (Enumtype)); + end; + end if; + + -- We repeat the too late test in case it froze itself! + + if Rep_Item_Too_Late (Enumtype, N) then + null; + end if; + end Analyze_Enumeration_Representation_Clause; + + ---------------------------- + -- Analyze_Free_Statement -- + ---------------------------- + + procedure Analyze_Free_Statement (N : Node_Id) is + begin + Analyze (Expression (N)); + end Analyze_Free_Statement; + + --------------------------- + -- Analyze_Freeze_Entity -- + --------------------------- + + procedure Analyze_Freeze_Entity (N : Node_Id) is + E : constant Entity_Id := Entity (N); + + begin + -- Remember that we are processing a freezing entity. Required to + -- ensure correct decoration of internal entities associated with + -- interfaces (see New_Overloaded_Entity). + + Inside_Freezing_Actions := Inside_Freezing_Actions + 1; + + -- For tagged types covering interfaces add internal entities that link + -- the primitives of the interfaces with the primitives that cover them. + -- Note: These entities were originally generated only when generating + -- code because their main purpose was to provide support to initialize + -- the secondary dispatch tables. They are now generated also when + -- compiling with no code generation to provide ASIS the relationship + -- between interface primitives and tagged type primitives. They are + -- also used to locate primitives covering interfaces when processing + -- generics (see Derive_Subprograms). + + if Ada_Version >= Ada_2005 + and then Ekind (E) = E_Record_Type + and then Is_Tagged_Type (E) + and then not Is_Interface (E) + and then Has_Interfaces (E) + then + -- This would be a good common place to call the routine that checks + -- overriding of interface primitives (and thus factorize calls to + -- Check_Abstract_Overriding located at different contexts in the + -- compiler). However, this is not possible because it causes + -- spurious errors in case of late overriding. + + Add_Internal_Interface_Entities (E); + end if; + + -- Check CPP types + + if Ekind (E) = E_Record_Type + and then Is_CPP_Class (E) + and then Is_Tagged_Type (E) + and then Tagged_Type_Expansion + and then Expander_Active + then + if CPP_Num_Prims (E) = 0 then + + -- If the CPP type has user defined components then it must import + -- primitives from C++. This is required because if the C++ class + -- has no primitives then the C++ compiler does not added the _tag + -- component to the type. + + pragma Assert (Chars (First_Entity (E)) = Name_uTag); + + if First_Entity (E) /= Last_Entity (E) then + Error_Msg_N + ("?'C'P'P type must import at least one primitive from C++", + E); + end if; + end if; + + -- Check that all its primitives are abstract or imported from C++. + -- Check also availability of the C++ constructor. + + declare + Has_Constructors : constant Boolean := Has_CPP_Constructors (E); + Elmt : Elmt_Id; + Error_Reported : Boolean := False; + Prim : Node_Id; + + begin + Elmt := First_Elmt (Primitive_Operations (E)); + while Present (Elmt) loop + Prim := Node (Elmt); + + if Comes_From_Source (Prim) then + if Is_Abstract_Subprogram (Prim) then + null; + + elsif not Is_Imported (Prim) + or else Convention (Prim) /= Convention_CPP + then + Error_Msg_N + ("?primitives of 'C'P'P types must be imported from C++" + & " or abstract", Prim); + + elsif not Has_Constructors + and then not Error_Reported + then + Error_Msg_Name_1 := Chars (E); + Error_Msg_N + ("?'C'P'P constructor required for type %", Prim); + Error_Reported := True; + end if; + end if; + + Next_Elmt (Elmt); + end loop; + end; + end if; + + Inside_Freezing_Actions := Inside_Freezing_Actions - 1; + + -- If we have a type with predicates, build predicate function + + if Is_Type (E) and then Has_Predicates (E) then + Build_Predicate_Function (E, N); + end if; + end Analyze_Freeze_Entity; + + ------------------------------------------ + -- Analyze_Record_Representation_Clause -- + ------------------------------------------ + + -- Note: we check as much as we can here, but we can't do any checks + -- based on the position values (e.g. overlap checks) until freeze time + -- because especially in Ada 2005 (machine scalar mode), the processing + -- for non-standard bit order can substantially change the positions. + -- See procedure Check_Record_Representation_Clause (called from Freeze) + -- for the remainder of this processing. + + procedure Analyze_Record_Representation_Clause (N : Node_Id) is + Ident : constant Node_Id := Identifier (N); + Biased : Boolean; + CC : Node_Id; + Comp : Entity_Id; + Fbit : Uint; + Hbit : Uint := Uint_0; + Lbit : Uint; + Ocomp : Entity_Id; + Posit : Uint; + Rectype : Entity_Id; + + CR_Pragma : Node_Id := Empty; + -- Points to N_Pragma node if Complete_Representation pragma present + + begin + if Ignore_Rep_Clauses then + return; + end if; + + Find_Type (Ident); + Rectype := Entity (Ident); + + if Rectype = Any_Type + or else Rep_Item_Too_Early (Rectype, N) + then + return; + else + Rectype := Underlying_Type (Rectype); + end if; + + -- First some basic error checks + + if not Is_Record_Type (Rectype) then + Error_Msg_NE + ("record type required, found}", Ident, First_Subtype (Rectype)); + return; + + elsif Scope (Rectype) /= Current_Scope then + Error_Msg_N ("type must be declared in this scope", N); + return; + + elsif not Is_First_Subtype (Rectype) then + Error_Msg_N ("cannot give record rep clause for subtype", N); + return; + + elsif Has_Record_Rep_Clause (Rectype) then + Error_Msg_N ("duplicate record rep clause ignored", N); + return; + + elsif Rep_Item_Too_Late (Rectype, N) then + return; + end if; + + if Present (Mod_Clause (N)) then + declare + Loc : constant Source_Ptr := Sloc (N); + M : constant Node_Id := Mod_Clause (N); + P : constant List_Id := Pragmas_Before (M); + AtM_Nod : Node_Id; + + Mod_Val : Uint; + pragma Warnings (Off, Mod_Val); + + begin + Check_Restriction (No_Obsolescent_Features, Mod_Clause (N)); + + if Warn_On_Obsolescent_Feature then + Error_Msg_N + ("mod clause is an obsolescent feature (RM J.8)?", N); + Error_Msg_N + ("\use alignment attribute definition clause instead?", N); + end if; + + if Present (P) then + Analyze_List (P); + end if; + + -- In ASIS_Mode mode, expansion is disabled, but we must convert + -- the Mod clause into an alignment clause anyway, so that the + -- back-end can compute and back-annotate properly the size and + -- alignment of types that may include this record. + + -- This seems dubious, this destroys the source tree in a manner + -- not detectable by ASIS ??? + + if Operating_Mode = Check_Semantics + and then ASIS_Mode + then + AtM_Nod := + Make_Attribute_Definition_Clause (Loc, + Name => New_Reference_To (Base_Type (Rectype), Loc), + Chars => Name_Alignment, + Expression => Relocate_Node (Expression (M))); + + Set_From_At_Mod (AtM_Nod); + Insert_After (N, AtM_Nod); + Mod_Val := Get_Alignment_Value (Expression (AtM_Nod)); + Set_Mod_Clause (N, Empty); + + else + -- Get the alignment value to perform error checking + + Mod_Val := Get_Alignment_Value (Expression (M)); + end if; + end; + end if; + + -- For untagged types, clear any existing component clauses for the + -- type. If the type is derived, this is what allows us to override + -- a rep clause for the parent. For type extensions, the representation + -- of the inherited components is inherited, so we want to keep previous + -- component clauses for completeness. + + if not Is_Tagged_Type (Rectype) then + Comp := First_Component_Or_Discriminant (Rectype); + while Present (Comp) loop + Set_Component_Clause (Comp, Empty); + Next_Component_Or_Discriminant (Comp); + end loop; + end if; + + -- All done if no component clauses + + CC := First (Component_Clauses (N)); + + if No (CC) then + return; + end if; + + -- A representation like this applies to the base type + + Set_Has_Record_Rep_Clause (Base_Type (Rectype)); + Set_Has_Non_Standard_Rep (Base_Type (Rectype)); + Set_Has_Specified_Layout (Base_Type (Rectype)); + + -- Process the component clauses + + while Present (CC) loop + + -- Pragma + + if Nkind (CC) = N_Pragma then + Analyze (CC); + + -- The only pragma of interest is Complete_Representation + + if Pragma_Name (CC) = Name_Complete_Representation then + CR_Pragma := CC; + end if; + + -- Processing for real component clause + + else + Posit := Static_Integer (Position (CC)); + Fbit := Static_Integer (First_Bit (CC)); + Lbit := Static_Integer (Last_Bit (CC)); + + if Posit /= No_Uint + and then Fbit /= No_Uint + and then Lbit /= No_Uint + then + if Posit < 0 then + Error_Msg_N + ("position cannot be negative", Position (CC)); + + elsif Fbit < 0 then + Error_Msg_N + ("first bit cannot be negative", First_Bit (CC)); + + -- The Last_Bit specified in a component clause must not be + -- less than the First_Bit minus one (RM-13.5.1(10)). + + elsif Lbit < Fbit - 1 then + Error_Msg_N + ("last bit cannot be less than first bit minus one", + Last_Bit (CC)); + + -- Values look OK, so find the corresponding record component + -- Even though the syntax allows an attribute reference for + -- implementation-defined components, GNAT does not allow the + -- tag to get an explicit position. + + elsif Nkind (Component_Name (CC)) = N_Attribute_Reference then + if Attribute_Name (Component_Name (CC)) = Name_Tag then + Error_Msg_N ("position of tag cannot be specified", CC); + else + Error_Msg_N ("illegal component name", CC); + end if; + + else + Comp := First_Entity (Rectype); + while Present (Comp) loop + exit when Chars (Comp) = Chars (Component_Name (CC)); + Next_Entity (Comp); + end loop; + + if No (Comp) then + + -- Maybe component of base type that is absent from + -- statically constrained first subtype. + + Comp := First_Entity (Base_Type (Rectype)); + while Present (Comp) loop + exit when Chars (Comp) = Chars (Component_Name (CC)); + Next_Entity (Comp); + end loop; + end if; + + if No (Comp) then + Error_Msg_N + ("component clause is for non-existent field", CC); + + -- Ada 2012 (AI05-0026): Any name that denotes a + -- discriminant of an object of an unchecked union type + -- shall not occur within a record_representation_clause. + + -- The general restriction of using record rep clauses on + -- Unchecked_Union types has now been lifted. Since it is + -- possible to introduce a record rep clause which mentions + -- the discriminant of an Unchecked_Union in non-Ada 2012 + -- code, this check is applied to all versions of the + -- language. + + elsif Ekind (Comp) = E_Discriminant + and then Is_Unchecked_Union (Rectype) + then + Error_Msg_N + ("cannot reference discriminant of Unchecked_Union", + Component_Name (CC)); + + elsif Present (Component_Clause (Comp)) then + + -- Diagnose duplicate rep clause, or check consistency + -- if this is an inherited component. In a double fault, + -- there may be a duplicate inconsistent clause for an + -- inherited component. + + if Scope (Original_Record_Component (Comp)) = Rectype + or else Parent (Component_Clause (Comp)) = N + then + Error_Msg_Sloc := Sloc (Component_Clause (Comp)); + Error_Msg_N ("component clause previously given#", CC); + + else + declare + Rep1 : constant Node_Id := Component_Clause (Comp); + begin + if Intval (Position (Rep1)) /= + Intval (Position (CC)) + or else Intval (First_Bit (Rep1)) /= + Intval (First_Bit (CC)) + or else Intval (Last_Bit (Rep1)) /= + Intval (Last_Bit (CC)) + then + Error_Msg_N ("component clause inconsistent " + & "with representation of ancestor", CC); + elsif Warn_On_Redundant_Constructs then + Error_Msg_N ("?redundant component clause " + & "for inherited component!", CC); + end if; + end; + end if; + + -- Normal case where this is the first component clause we + -- have seen for this entity, so set it up properly. + + else + -- Make reference for field in record rep clause and set + -- appropriate entity field in the field identifier. + + Generate_Reference + (Comp, Component_Name (CC), Set_Ref => False); + Set_Entity (Component_Name (CC), Comp); + + -- Update Fbit and Lbit to the actual bit number + + Fbit := Fbit + UI_From_Int (SSU) * Posit; + Lbit := Lbit + UI_From_Int (SSU) * Posit; + + if Has_Size_Clause (Rectype) + and then Esize (Rectype) <= Lbit + then + Error_Msg_N + ("bit number out of range of specified size", + Last_Bit (CC)); + else + Set_Component_Clause (Comp, CC); + Set_Component_Bit_Offset (Comp, Fbit); + Set_Esize (Comp, 1 + (Lbit - Fbit)); + Set_Normalized_First_Bit (Comp, Fbit mod SSU); + Set_Normalized_Position (Comp, Fbit / SSU); + + if Warn_On_Overridden_Size + and then Has_Size_Clause (Etype (Comp)) + and then RM_Size (Etype (Comp)) /= Esize (Comp) + then + Error_Msg_NE + ("?component size overrides size clause for&", + Component_Name (CC), Etype (Comp)); + end if; + + -- This information is also set in the corresponding + -- component of the base type, found by accessing the + -- Original_Record_Component link if it is present. + + Ocomp := Original_Record_Component (Comp); + + if Hbit < Lbit then + Hbit := Lbit; + end if; + + Check_Size + (Component_Name (CC), + Etype (Comp), + Esize (Comp), + Biased); + + Set_Biased + (Comp, First_Node (CC), "component clause", Biased); + + if Present (Ocomp) then + Set_Component_Clause (Ocomp, CC); + Set_Component_Bit_Offset (Ocomp, Fbit); + Set_Normalized_First_Bit (Ocomp, Fbit mod SSU); + Set_Normalized_Position (Ocomp, Fbit / SSU); + Set_Esize (Ocomp, 1 + (Lbit - Fbit)); + + Set_Normalized_Position_Max + (Ocomp, Normalized_Position (Ocomp)); + + -- Note: we don't use Set_Biased here, because we + -- already gave a warning above if needed, and we + -- would get a duplicate for the same name here. + + Set_Has_Biased_Representation + (Ocomp, Has_Biased_Representation (Comp)); + end if; + + if Esize (Comp) < 0 then + Error_Msg_N ("component size is negative", CC); + end if; + end if; + end if; + end if; + end if; + end if; + + Next (CC); + end loop; + + -- Check missing components if Complete_Representation pragma appeared + + if Present (CR_Pragma) then + Comp := First_Component_Or_Discriminant (Rectype); + while Present (Comp) loop + if No (Component_Clause (Comp)) then + Error_Msg_NE + ("missing component clause for &", CR_Pragma, Comp); + end if; + + Next_Component_Or_Discriminant (Comp); + end loop; + + -- If no Complete_Representation pragma, warn if missing components + + elsif Warn_On_Unrepped_Components then + declare + Num_Repped_Components : Nat := 0; + Num_Unrepped_Components : Nat := 0; + + begin + -- First count number of repped and unrepped components + + Comp := First_Component_Or_Discriminant (Rectype); + while Present (Comp) loop + if Present (Component_Clause (Comp)) then + Num_Repped_Components := Num_Repped_Components + 1; + else + Num_Unrepped_Components := Num_Unrepped_Components + 1; + end if; + + Next_Component_Or_Discriminant (Comp); + end loop; + + -- We are only interested in the case where there is at least one + -- unrepped component, and at least half the components have rep + -- clauses. We figure that if less than half have them, then the + -- partial rep clause is really intentional. If the component + -- type has no underlying type set at this point (as for a generic + -- formal type), we don't know enough to give a warning on the + -- component. + + if Num_Unrepped_Components > 0 + and then Num_Unrepped_Components < Num_Repped_Components + then + Comp := First_Component_Or_Discriminant (Rectype); + while Present (Comp) loop + if No (Component_Clause (Comp)) + and then Comes_From_Source (Comp) + and then Present (Underlying_Type (Etype (Comp))) + and then (Is_Scalar_Type (Underlying_Type (Etype (Comp))) + or else Size_Known_At_Compile_Time + (Underlying_Type (Etype (Comp)))) + and then not Has_Warnings_Off (Rectype) + then + Error_Msg_Sloc := Sloc (Comp); + Error_Msg_NE + ("?no component clause given for & declared #", + N, Comp); + end if; + + Next_Component_Or_Discriminant (Comp); + end loop; + end if; + end; + end if; + end Analyze_Record_Representation_Clause; + + ------------------------------- + -- Build_Invariant_Procedure -- + ------------------------------- + + -- The procedure that is constructed here has the form + + -- procedure typInvariant (Ixxx : typ) is + -- begin + -- pragma Check (Invariant, exp, "failed invariant from xxx"); + -- pragma Check (Invariant, exp, "failed invariant from xxx"); + -- ... + -- pragma Check (Invariant, exp, "failed inherited invariant from xxx"); + -- ... + -- end typInvariant; + + procedure Build_Invariant_Procedure (Typ : Entity_Id; N : Node_Id) is + Loc : constant Source_Ptr := Sloc (Typ); + Stmts : List_Id; + Spec : Node_Id; + SId : Entity_Id; + PDecl : Node_Id; + PBody : Node_Id; + + Visible_Decls : constant List_Id := Visible_Declarations (N); + Private_Decls : constant List_Id := Private_Declarations (N); + + procedure Add_Invariants (T : Entity_Id; Inherit : Boolean); + -- Appends statements to Stmts for any invariants in the rep item chain + -- of the given type. If Inherit is False, then we only process entries + -- on the chain for the type Typ. If Inherit is True, then we ignore any + -- Invariant aspects, but we process all Invariant'Class aspects, adding + -- "inherited" to the exception message and generating an informational + -- message about the inheritance of an invariant. + + Object_Name : constant Name_Id := New_Internal_Name ('I'); + -- Name for argument of invariant procedure + + Object_Entity : constant Node_Id := + Make_Defining_Identifier (Loc, Object_Name); + -- The procedure declaration entity for the argument + + -------------------- + -- Add_Invariants -- + -------------------- + + procedure Add_Invariants (T : Entity_Id; Inherit : Boolean) is + Ritem : Node_Id; + Arg1 : Node_Id; + Arg2 : Node_Id; + Arg3 : Node_Id; + Exp : Node_Id; + Loc : Source_Ptr; + Assoc : List_Id; + Str : String_Id; + + procedure Replace_Type_Reference (N : Node_Id); + -- Replace a single occurrence N of the subtype name with a reference + -- to the formal of the predicate function. N can be an identifier + -- referencing the subtype, or a selected component, representing an + -- appropriately qualified occurrence of the subtype name. + + procedure Replace_Type_References is + new Replace_Type_References_Generic (Replace_Type_Reference); + -- Traverse an expression replacing all occurrences of the subtype + -- name with appropriate references to the object that is the formal + -- parameter of the predicate function. Note that we must ensure + -- that the type and entity information is properly set in the + -- replacement node, since we will do a Preanalyze call of this + -- expression without proper visibility of the procedure argument. + + ---------------------------- + -- Replace_Type_Reference -- + ---------------------------- + + procedure Replace_Type_Reference (N : Node_Id) is + begin + -- Invariant'Class, replace with T'Class (obj) + + if Class_Present (Ritem) then + Rewrite (N, + Make_Type_Conversion (Loc, + Subtype_Mark => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (T, Loc), + Attribute_Name => Name_Class), + Expression => Make_Identifier (Loc, Object_Name))); + + Set_Entity (Expression (N), Object_Entity); + Set_Etype (Expression (N), Typ); + + -- Invariant, replace with obj + + else + Rewrite (N, Make_Identifier (Loc, Object_Name)); + Set_Entity (N, Object_Entity); + Set_Etype (N, Typ); + end if; + end Replace_Type_Reference; + + -- Start of processing for Add_Invariants + + begin + Ritem := First_Rep_Item (T); + while Present (Ritem) loop + if Nkind (Ritem) = N_Pragma + and then Pragma_Name (Ritem) = Name_Invariant + then + Arg1 := First (Pragma_Argument_Associations (Ritem)); + Arg2 := Next (Arg1); + Arg3 := Next (Arg2); + + Arg1 := Get_Pragma_Arg (Arg1); + Arg2 := Get_Pragma_Arg (Arg2); + + -- For Inherit case, ignore Invariant, process only Class case + + if Inherit then + if not Class_Present (Ritem) then + goto Continue; + end if; + + -- For Inherit false, process only item for right type + + else + if Entity (Arg1) /= Typ then + goto Continue; + end if; + end if; + + if No (Stmts) then + Stmts := Empty_List; + end if; + + Exp := New_Copy_Tree (Arg2); + Loc := Sloc (Exp); + + -- We need to replace any occurrences of the name of the type + -- with references to the object, converted to type'Class in + -- the case of Invariant'Class aspects. + + Replace_Type_References (Exp, Chars (T)); + + -- Now we need to preanalyze the expression to properly capture + -- the visibility in the visible part. The expression will not + -- be analyzed for real until the body is analyzed, but that is + -- at the end of the private part and has the wrong visibility. + + Set_Parent (Exp, N); + Preanalyze_Spec_Expression (Exp, Standard_Boolean); + + -- Build first two arguments for Check pragma + + Assoc := New_List ( + Make_Pragma_Argument_Association (Loc, + Expression => Make_Identifier (Loc, Name_Invariant)), + Make_Pragma_Argument_Association (Loc, Expression => Exp)); + + -- Add message if present in Invariant pragma + + if Present (Arg3) then + Str := Strval (Get_Pragma_Arg (Arg3)); + + -- If inherited case, and message starts "failed invariant", + -- change it to be "failed inherited invariant". + + if Inherit then + String_To_Name_Buffer (Str); + + if Name_Buffer (1 .. 16) = "failed invariant" then + Insert_Str_In_Name_Buffer ("inherited ", 8); + Str := String_From_Name_Buffer; + end if; + end if; + + Append_To (Assoc, + Make_Pragma_Argument_Association (Loc, + Expression => Make_String_Literal (Loc, Str))); + end if; + + -- Add Check pragma to list of statements + + Append_To (Stmts, + Make_Pragma (Loc, + Pragma_Identifier => + Make_Identifier (Loc, Name_Check), + Pragma_Argument_Associations => Assoc)); + + -- If Inherited case and option enabled, output info msg. Note + -- that we know this is a case of Invariant'Class. + + if Inherit and Opt.List_Inherited_Aspects then + Error_Msg_Sloc := Sloc (Ritem); + Error_Msg_N + ("?info: & inherits `Invariant''Class` aspect from #", + Typ); + end if; + end if; + + <> + Next_Rep_Item (Ritem); + end loop; + end Add_Invariants; + + -- Start of processing for Build_Invariant_Procedure + + begin + Stmts := No_List; + PDecl := Empty; + PBody := Empty; + Set_Etype (Object_Entity, Typ); + + -- Add invariants for the current type + + Add_Invariants (Typ, Inherit => False); + + -- Add invariants for parent types + + declare + Current_Typ : Entity_Id; + Parent_Typ : Entity_Id; + + begin + Current_Typ := Typ; + loop + Parent_Typ := Etype (Current_Typ); + + if Is_Private_Type (Parent_Typ) + and then Present (Full_View (Base_Type (Parent_Typ))) + then + Parent_Typ := Full_View (Base_Type (Parent_Typ)); + end if; + + exit when Parent_Typ = Current_Typ; + + Current_Typ := Parent_Typ; + Add_Invariants (Current_Typ, Inherit => True); + end loop; + end; + + -- Build the procedure if we generated at least one Check pragma + + if Stmts /= No_List then + + -- Build procedure declaration + + SId := + Make_Defining_Identifier (Loc, + Chars => New_External_Name (Chars (Typ), "Invariant")); + Set_Has_Invariants (SId); + Set_Invariant_Procedure (Typ, SId); + + Spec := + Make_Procedure_Specification (Loc, + Defining_Unit_Name => SId, + Parameter_Specifications => New_List ( + Make_Parameter_Specification (Loc, + Defining_Identifier => Object_Entity, + Parameter_Type => New_Occurrence_Of (Typ, Loc)))); + + PDecl := Make_Subprogram_Declaration (Loc, Specification => Spec); + + -- Build procedure body + + SId := + Make_Defining_Identifier (Loc, + Chars => New_External_Name (Chars (Typ), "Invariant")); + + Spec := + Make_Procedure_Specification (Loc, + Defining_Unit_Name => SId, + Parameter_Specifications => New_List ( + Make_Parameter_Specification (Loc, + Defining_Identifier => + Make_Defining_Identifier (Loc, Object_Name), + Parameter_Type => New_Occurrence_Of (Typ, Loc)))); + + PBody := + Make_Subprogram_Body (Loc, + Specification => Spec, + Declarations => Empty_List, + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => Stmts)); + + -- Insert procedure declaration and spec at the appropriate points. + -- Skip this if there are no private declarations (that's an error + -- that will be diagnosed elsewhere, and there is no point in having + -- an invariant procedure set if the full declaration is missing). + + if Present (Private_Decls) then + + -- The spec goes at the end of visible declarations, but they have + -- already been analyzed, so we need to explicitly do the analyze. + + Append_To (Visible_Decls, PDecl); + Analyze (PDecl); + + -- The body goes at the end of the private declarations, which we + -- have not analyzed yet, so we do not need to perform an explicit + -- analyze call. We skip this if there are no private declarations + -- (this is an error that will be caught elsewhere); + + Append_To (Private_Decls, PBody); + end if; + end if; + end Build_Invariant_Procedure; + + ------------------------------ + -- Build_Predicate_Function -- + ------------------------------ + + -- The procedure that is constructed here has the form + + -- function typPredicate (Ixxx : typ) return Boolean is + -- begin + -- return + -- exp1 and then exp2 and then ... + -- and then typ1Predicate (typ1 (Ixxx)) + -- and then typ2Predicate (typ2 (Ixxx)) + -- and then ...; + -- end typPredicate; + + -- Here exp1, and exp2 are expressions from Predicate pragmas. Note that + -- this is the point at which these expressions get analyzed, providing the + -- required delay, and typ1, typ2, are entities from which predicates are + -- inherited. Note that we do NOT generate Check pragmas, that's because we + -- use this function even if checks are off, e.g. for membership tests. + + procedure Build_Predicate_Function (Typ : Entity_Id; N : Node_Id) is + Loc : constant Source_Ptr := Sloc (Typ); + Spec : Node_Id; + SId : Entity_Id; + FDecl : Node_Id; + FBody : Node_Id; + + Expr : Node_Id; + -- This is the expression for the return statement in the function. It + -- is build by connecting the component predicates with AND THEN. + + procedure Add_Call (T : Entity_Id); + -- Includes a call to the predicate function for type T in Expr if T + -- has predicates and Predicate_Function (T) is non-empty. + + procedure Add_Predicates; + -- Appends expressions for any Predicate pragmas in the rep item chain + -- Typ to Expr. Note that we look only at items for this exact entity. + -- Inheritance of predicates for the parent type is done by calling the + -- Predicate_Function of the parent type, using Add_Call above. + + Object_Name : constant Name_Id := New_Internal_Name ('I'); + -- Name for argument of Predicate procedure + + -------------- + -- Add_Call -- + -------------- + + procedure Add_Call (T : Entity_Id) is + Exp : Node_Id; + + begin + if Present (T) and then Present (Predicate_Function (T)) then + Set_Has_Predicates (Typ); + + -- Build the call to the predicate function of T + + Exp := + Make_Predicate_Call + (T, Convert_To (T, Make_Identifier (Loc, Object_Name))); + + -- Add call to evolving expression, using AND THEN if needed + + if No (Expr) then + Expr := Exp; + else + Expr := + Make_And_Then (Loc, + Left_Opnd => Relocate_Node (Expr), + Right_Opnd => Exp); + end if; + + -- Output info message on inheritance if required. Note we do not + -- give this information for generic actual types, since it is + -- unwelcome noise in that case in instantiations. We also + -- generally suppress the message in instantiations, and also + -- if it involves internal names. + + if Opt.List_Inherited_Aspects + and then not Is_Generic_Actual_Type (Typ) + and then Instantiation_Depth (Sloc (Typ)) = 0 + and then not Is_Internal_Name (Chars (T)) + and then not Is_Internal_Name (Chars (Typ)) + then + Error_Msg_Sloc := Sloc (Predicate_Function (T)); + Error_Msg_Node_2 := T; + Error_Msg_N ("?info: & inherits predicate from & #", Typ); + end if; + end if; + end Add_Call; + + -------------------- + -- Add_Predicates -- + -------------------- + + procedure Add_Predicates is + Ritem : Node_Id; + Arg1 : Node_Id; + Arg2 : Node_Id; + + procedure Replace_Type_Reference (N : Node_Id); + -- Replace a single occurrence N of the subtype name with a reference + -- to the formal of the predicate function. N can be an identifier + -- referencing the subtype, or a selected component, representing an + -- appropriately qualified occurrence of the subtype name. + + procedure Replace_Type_References is + new Replace_Type_References_Generic (Replace_Type_Reference); + -- Traverse an expression changing every occurrence of an identifier + -- whose name matches the name of the subtype with a reference to + -- the formal parameter of the predicate function. + + ---------------------------- + -- Replace_Type_Reference -- + ---------------------------- + + procedure Replace_Type_Reference (N : Node_Id) is + begin + Rewrite (N, Make_Identifier (Loc, Object_Name)); + end Replace_Type_Reference; + + -- Start of processing for Add_Predicates + + begin + Ritem := First_Rep_Item (Typ); + while Present (Ritem) loop + if Nkind (Ritem) = N_Pragma + and then Pragma_Name (Ritem) = Name_Predicate + then + Arg1 := First (Pragma_Argument_Associations (Ritem)); + Arg2 := Next (Arg1); + + Arg1 := Get_Pragma_Arg (Arg1); + Arg2 := Get_Pragma_Arg (Arg2); + + -- See if this predicate pragma is for the current type + + if Entity (Arg1) = Typ then + + -- We have a match, this entry is for our subtype + + -- First We need to replace any occurrences of the name of + -- the type with references to the object. + + Replace_Type_References (Arg2, Chars (Typ)); + + -- OK, replacement complete, now we can add the expression + + if No (Expr) then + Expr := Relocate_Node (Arg2); + + -- There already was a predicate, so add to it + + else + Expr := + Make_And_Then (Loc, + Left_Opnd => Relocate_Node (Expr), + Right_Opnd => Relocate_Node (Arg2)); + end if; + end if; + end if; + + Next_Rep_Item (Ritem); + end loop; + end Add_Predicates; + + -- Start of processing for Build_Predicate_Function + + begin + -- Initialize for construction of statement list + + Expr := Empty; + + -- Return if already built or if type does not have predicates + + if not Has_Predicates (Typ) + or else Present (Predicate_Function (Typ)) + then + return; + end if; + + -- Add Predicates for the current type + + Add_Predicates; + + -- Add predicates for ancestor if present + + declare + Atyp : constant Entity_Id := Nearest_Ancestor (Typ); + begin + if Present (Atyp) then + Add_Call (Atyp); + end if; + end; + + -- If we have predicates, build the function + + if Present (Expr) then + + -- Build function declaration + + pragma Assert (Has_Predicates (Typ)); + SId := + Make_Defining_Identifier (Loc, + Chars => New_External_Name (Chars (Typ), "Predicate")); + Set_Has_Predicates (SId); + Set_Predicate_Function (Typ, SId); + + Spec := + Make_Function_Specification (Loc, + Defining_Unit_Name => SId, + Parameter_Specifications => New_List ( + Make_Parameter_Specification (Loc, + Defining_Identifier => + Make_Defining_Identifier (Loc, Object_Name), + Parameter_Type => New_Occurrence_Of (Typ, Loc))), + Result_Definition => + New_Occurrence_Of (Standard_Boolean, Loc)); + + FDecl := Make_Subprogram_Declaration (Loc, Specification => Spec); + + -- Build function body + + SId := + Make_Defining_Identifier (Loc, + Chars => New_External_Name (Chars (Typ), "Predicate")); + + Spec := + Make_Function_Specification (Loc, + Defining_Unit_Name => SId, + Parameter_Specifications => New_List ( + Make_Parameter_Specification (Loc, + Defining_Identifier => + Make_Defining_Identifier (Loc, Object_Name), + Parameter_Type => + New_Occurrence_Of (Typ, Loc))), + Result_Definition => + New_Occurrence_Of (Standard_Boolean, Loc)); + + FBody := + Make_Subprogram_Body (Loc, + Specification => Spec, + Declarations => Empty_List, + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List ( + Make_Simple_Return_Statement (Loc, + Expression => Expr)))); + + -- Insert declaration before freeze node and body after + + Insert_Before_And_Analyze (N, FDecl); + Insert_After_And_Analyze (N, FBody); + + -- Deal with static predicate case + + if Ekind_In (Typ, E_Enumeration_Subtype, + E_Modular_Integer_Subtype, + E_Signed_Integer_Subtype) + and then Is_Static_Subtype (Typ) + then + Build_Static_Predicate (Typ, Expr, Object_Name); + end if; + end if; + end Build_Predicate_Function; + + ---------------------------- + -- Build_Static_Predicate -- + ---------------------------- + + procedure Build_Static_Predicate + (Typ : Entity_Id; + Expr : Node_Id; + Nam : Name_Id) + is + Loc : constant Source_Ptr := Sloc (Expr); + + Non_Static : exception; + -- Raised if something non-static is found + + Btyp : constant Entity_Id := Base_Type (Typ); + + BLo : constant Uint := Expr_Value (Type_Low_Bound (Btyp)); + BHi : constant Uint := Expr_Value (Type_High_Bound (Btyp)); + -- Low bound and high bound value of base type of Typ + + TLo : constant Uint := Expr_Value (Type_Low_Bound (Typ)); + THi : constant Uint := Expr_Value (Type_High_Bound (Typ)); + -- Low bound and high bound values of static subtype Typ + + type REnt is record + Lo, Hi : Uint; + end record; + -- One entry in a Rlist value, a single REnt (range entry) value + -- denotes one range from Lo to Hi. To represent a single value + -- range Lo = Hi = value. + + type RList is array (Nat range <>) of REnt; + -- A list of ranges. The ranges are sorted in increasing order, + -- and are disjoint (there is a gap of at least one value between + -- each range in the table). A value is in the set of ranges in + -- Rlist if it lies within one of these ranges + + False_Range : constant RList := + RList'(1 .. 0 => REnt'(No_Uint, No_Uint)); + -- An empty set of ranges represents a range list that can never be + -- satisfied, since there are no ranges in which the value could lie, + -- so it does not lie in any of them. False_Range is a canonical value + -- for this empty set, but general processing should test for an Rlist + -- with length zero (see Is_False predicate), since other null ranges + -- may appear which must be treated as False. + + True_Range : constant RList := RList'(1 => REnt'(BLo, BHi)); + -- Range representing True, value must be in the base range + + function "and" (Left, Right : RList) return RList; + -- And's together two range lists, returning a range list. This is + -- a set intersection operation. + + function "or" (Left, Right : RList) return RList; + -- Or's together two range lists, returning a range list. This is a + -- set union operation. + + function "not" (Right : RList) return RList; + -- Returns complement of a given range list, i.e. a range list + -- representing all the values in TLo .. THi that are not in the + -- input operand Right. + + function Build_Val (V : Uint) return Node_Id; + -- Return an analyzed N_Identifier node referencing this value, suitable + -- for use as an entry in the Static_Predicate list. This node is typed + -- with the base type. + + function Build_Range (Lo, Hi : Uint) return Node_Id; + -- Return an analyzed N_Range node referencing this range, suitable + -- for use as an entry in the Static_Predicate list. This node is typed + -- with the base type. + + function Get_RList (Exp : Node_Id) return RList; + -- This is a recursive routine that converts the given expression into + -- a list of ranges, suitable for use in building the static predicate. + + function Is_False (R : RList) return Boolean; + pragma Inline (Is_False); + -- Returns True if the given range list is empty, and thus represents + -- a False list of ranges that can never be satisfied. + + function Is_True (R : RList) return Boolean; + -- Returns True if R trivially represents the True predicate by having + -- a single range from BLo to BHi. + + function Is_Type_Ref (N : Node_Id) return Boolean; + pragma Inline (Is_Type_Ref); + -- Returns if True if N is a reference to the type for the predicate in + -- the expression (i.e. if it is an identifier whose Chars field matches + -- the Nam given in the call). + + function Lo_Val (N : Node_Id) return Uint; + -- Given static expression or static range from a Static_Predicate list, + -- gets expression value or low bound of range. + + function Hi_Val (N : Node_Id) return Uint; + -- Given static expression or static range from a Static_Predicate list, + -- gets expression value of high bound of range. + + function Membership_Entry (N : Node_Id) return RList; + -- Given a single membership entry (range, value, or subtype), returns + -- the corresponding range list. Raises Static_Error if not static. + + function Membership_Entries (N : Node_Id) return RList; + -- Given an element on an alternatives list of a membership operation, + -- returns the range list corresponding to this entry and all following + -- entries (i.e. returns the "or" of this list of values). + + function Stat_Pred (Typ : Entity_Id) return RList; + -- Given a type, if it has a static predicate, then return the predicate + -- as a range list, otherwise raise Non_Static. + + ----------- + -- "and" -- + ----------- + + function "and" (Left, Right : RList) return RList is + FEnt : REnt; + -- First range of result + + SLeft : Nat := Left'First; + -- Start of rest of left entries + + SRight : Nat := Right'First; + -- Start of rest of right entries + + begin + -- If either range is True, return the other + + if Is_True (Left) then + return Right; + elsif Is_True (Right) then + return Left; + end if; + + -- If either range is False, return False + + if Is_False (Left) or else Is_False (Right) then + return False_Range; + end if; + + -- Loop to remove entries at start that are disjoint, and thus + -- just get discarded from the result entirely. + + loop + -- If no operands left in either operand, result is false + + if SLeft > Left'Last or else SRight > Right'Last then + return False_Range; + + -- Discard first left operand entry if disjoint with right + + elsif Left (SLeft).Hi < Right (SRight).Lo then + SLeft := SLeft + 1; + + -- Discard first right operand entry if disjoint with left + + elsif Right (SRight).Hi < Left (SLeft).Lo then + SRight := SRight + 1; + + -- Otherwise we have an overlapping entry + + else + exit; + end if; + end loop; + + -- Now we have two non-null operands, and first entries overlap. + -- The first entry in the result will be the overlapping part of + -- these two entries. + + FEnt := REnt'(Lo => UI_Max (Left (SLeft).Lo, Right (SRight).Lo), + Hi => UI_Min (Left (SLeft).Hi, Right (SRight).Hi)); + + -- Now we can remove the entry that ended at a lower value, since + -- its contribution is entirely contained in Fent. + + if Left (SLeft).Hi <= Right (SRight).Hi then + SLeft := SLeft + 1; + else + SRight := SRight + 1; + end if; + + -- Compute result by concatenating this first entry with the "and" + -- of the remaining parts of the left and right operands. Note that + -- if either of these is empty, "and" will yield empty, so that we + -- will end up with just Fent, which is what we want in that case. + + return + FEnt & (Left (SLeft .. Left'Last) and Right (SRight .. Right'Last)); + end "and"; + + ----------- + -- "not" -- + ----------- + + function "not" (Right : RList) return RList is + begin + -- Return True if False range + + if Is_False (Right) then + return True_Range; + end if; + + -- Return False if True range + + if Is_True (Right) then + return False_Range; + end if; + + -- Here if not trivial case + + declare + Result : RList (1 .. Right'Length + 1); + -- May need one more entry for gap at beginning and end + + Count : Nat := 0; + -- Number of entries stored in Result + + begin + -- Gap at start + + if Right (Right'First).Lo > TLo then + Count := Count + 1; + Result (Count) := REnt'(TLo, Right (Right'First).Lo - 1); + end if; + + -- Gaps between ranges + + for J in Right'First .. Right'Last - 1 loop + Count := Count + 1; + Result (Count) := + REnt'(Right (J).Hi + 1, Right (J + 1).Lo - 1); + end loop; + + -- Gap at end + + if Right (Right'Last).Hi < THi then + Count := Count + 1; + Result (Count) := REnt'(Right (Right'Last).Hi + 1, THi); + end if; + + return Result (1 .. Count); + end; + end "not"; + + ---------- + -- "or" -- + ---------- + + function "or" (Left, Right : RList) return RList is + FEnt : REnt; + -- First range of result + + SLeft : Nat := Left'First; + -- Start of rest of left entries + + SRight : Nat := Right'First; + -- Start of rest of right entries + + begin + -- If either range is True, return True + + if Is_True (Left) or else Is_True (Right) then + return True_Range; + end if; + + -- If either range is False (empty), return the other + + if Is_False (Left) then + return Right; + elsif Is_False (Right) then + return Left; + end if; + + -- Initialize result first entry from left or right operand + -- depending on which starts with the lower range. + + if Left (SLeft).Lo < Right (SRight).Lo then + FEnt := Left (SLeft); + SLeft := SLeft + 1; + else + FEnt := Right (SRight); + SRight := SRight + 1; + end if; + + -- This loop eats ranges from left and right operands that + -- are contiguous with the first range we are gathering. + + loop + -- Eat first entry in left operand if contiguous or + -- overlapped by gathered first operand of result. + + if SLeft <= Left'Last + and then Left (SLeft).Lo <= FEnt.Hi + 1 + then + FEnt.Hi := UI_Max (FEnt.Hi, Left (SLeft).Hi); + SLeft := SLeft + 1; + + -- Eat first entry in right operand if contiguous or + -- overlapped by gathered right operand of result. + + elsif SRight <= Right'Last + and then Right (SRight).Lo <= FEnt.Hi + 1 + then + FEnt.Hi := UI_Max (FEnt.Hi, Right (SRight).Hi); + SRight := SRight + 1; + + -- All done if no more entries to eat! + + else + exit; + end if; + end loop; + + -- Obtain result as the first entry we just computed, concatenated + -- to the "or" of the remaining results (if one operand is empty, + -- this will just concatenate with the other + + return + FEnt & (Left (SLeft .. Left'Last) or Right (SRight .. Right'Last)); + end "or"; + + ----------------- + -- Build_Range -- + ----------------- + + function Build_Range (Lo, Hi : Uint) return Node_Id is + Result : Node_Id; + begin + if Lo = Hi then + return Build_Val (Hi); + else + Result := + Make_Range (Loc, + Low_Bound => Build_Val (Lo), + High_Bound => Build_Val (Hi)); + Set_Etype (Result, Btyp); + Set_Analyzed (Result); + return Result; + end if; + end Build_Range; + + --------------- + -- Build_Val -- + --------------- + + function Build_Val (V : Uint) return Node_Id is + Result : Node_Id; + + begin + if Is_Enumeration_Type (Typ) then + Result := Get_Enum_Lit_From_Pos (Typ, V, Loc); + else + Result := Make_Integer_Literal (Loc, V); + end if; + + Set_Etype (Result, Btyp); + Set_Is_Static_Expression (Result); + Set_Analyzed (Result); + return Result; + end Build_Val; + + --------------- + -- Get_RList -- + --------------- + + function Get_RList (Exp : Node_Id) return RList is + Op : Node_Kind; + Val : Uint; + + begin + -- Static expression can only be true or false + + if Is_OK_Static_Expression (Exp) then + + -- For False + + if Expr_Value (Exp) = 0 then + return False_Range; + else + return True_Range; + end if; + end if; + + -- Otherwise test node type + + Op := Nkind (Exp); + + case Op is + + -- And + + when N_Op_And | N_And_Then => + return Get_RList (Left_Opnd (Exp)) + and + Get_RList (Right_Opnd (Exp)); + + -- Or + + when N_Op_Or | N_Or_Else => + return Get_RList (Left_Opnd (Exp)) + or + Get_RList (Right_Opnd (Exp)); + + -- Not + + when N_Op_Not => + return not Get_RList (Right_Opnd (Exp)); + + -- Comparisons of type with static value + + when N_Op_Compare => + -- Type is left operand + + if Is_Type_Ref (Left_Opnd (Exp)) + and then Is_OK_Static_Expression (Right_Opnd (Exp)) + then + Val := Expr_Value (Right_Opnd (Exp)); + + -- Typ is right operand + + elsif Is_Type_Ref (Right_Opnd (Exp)) + and then Is_OK_Static_Expression (Left_Opnd (Exp)) + then + Val := Expr_Value (Left_Opnd (Exp)); + + -- Invert sense of comparison + + case Op is + when N_Op_Gt => Op := N_Op_Lt; + when N_Op_Lt => Op := N_Op_Gt; + when N_Op_Ge => Op := N_Op_Le; + when N_Op_Le => Op := N_Op_Ge; + when others => null; + end case; + + -- Other cases are non-static + + else + raise Non_Static; + end if; + + -- Construct range according to comparison operation + + case Op is + when N_Op_Eq => + return RList'(1 => REnt'(Val, Val)); + + when N_Op_Ge => + return RList'(1 => REnt'(Val, BHi)); + + when N_Op_Gt => + return RList'(1 => REnt'(Val + 1, BHi)); + + when N_Op_Le => + return RList'(1 => REnt'(BLo, Val)); + + when N_Op_Lt => + return RList'(1 => REnt'(BLo, Val - 1)); + + when N_Op_Ne => + return RList'(REnt'(BLo, Val - 1), + REnt'(Val + 1, BHi)); + + when others => + raise Program_Error; + end case; + + -- Membership (IN) + + when N_In => + if not Is_Type_Ref (Left_Opnd (Exp)) then + raise Non_Static; + end if; + + if Present (Right_Opnd (Exp)) then + return Membership_Entry (Right_Opnd (Exp)); + else + return Membership_Entries (First (Alternatives (Exp))); + end if; + + -- Negative membership (NOT IN) + + when N_Not_In => + if not Is_Type_Ref (Left_Opnd (Exp)) then + raise Non_Static; + end if; + + if Present (Right_Opnd (Exp)) then + return not Membership_Entry (Right_Opnd (Exp)); + else + return not Membership_Entries (First (Alternatives (Exp))); + end if; + + -- Function call, may be call to static predicate + + when N_Function_Call => + if Is_Entity_Name (Name (Exp)) then + declare + Ent : constant Entity_Id := Entity (Name (Exp)); + begin + if Has_Predicates (Ent) then + return Stat_Pred (Etype (First_Formal (Ent))); + end if; + end; + end if; + + -- Other function call cases are non-static + + raise Non_Static; + + -- Qualified expression, dig out the expression + + when N_Qualified_Expression => + return Get_RList (Expression (Exp)); + + -- Xor operator + + when N_Op_Xor => + return (Get_RList (Left_Opnd (Exp)) + and not Get_RList (Right_Opnd (Exp))) + or (Get_RList (Right_Opnd (Exp)) + and not Get_RList (Left_Opnd (Exp))); + + -- Any other node type is non-static + + when others => + raise Non_Static; + end case; + end Get_RList; + + ------------ + -- Hi_Val -- + ------------ + + function Hi_Val (N : Node_Id) return Uint is + begin + if Is_Static_Expression (N) then + return Expr_Value (N); + else + pragma Assert (Nkind (N) = N_Range); + return Expr_Value (High_Bound (N)); + end if; + end Hi_Val; + + -------------- + -- Is_False -- + -------------- + + function Is_False (R : RList) return Boolean is + begin + return R'Length = 0; + end Is_False; + + ------------- + -- Is_True -- + ------------- + + function Is_True (R : RList) return Boolean is + begin + return R'Length = 1 + and then R (R'First).Lo = BLo + and then R (R'First).Hi = BHi; + end Is_True; + + ----------------- + -- Is_Type_Ref -- + ----------------- + + function Is_Type_Ref (N : Node_Id) return Boolean is + begin + return Nkind (N) = N_Identifier and then Chars (N) = Nam; + end Is_Type_Ref; + + ------------ + -- Lo_Val -- + ------------ + + function Lo_Val (N : Node_Id) return Uint is + begin + if Is_Static_Expression (N) then + return Expr_Value (N); + else + pragma Assert (Nkind (N) = N_Range); + return Expr_Value (Low_Bound (N)); + end if; + end Lo_Val; + + ------------------------ + -- Membership_Entries -- + ------------------------ + + function Membership_Entries (N : Node_Id) return RList is + begin + if No (Next (N)) then + return Membership_Entry (N); + else + return Membership_Entry (N) or Membership_Entries (Next (N)); + end if; + end Membership_Entries; + + ---------------------- + -- Membership_Entry -- + ---------------------- + + function Membership_Entry (N : Node_Id) return RList is + Val : Uint; + SLo : Uint; + SHi : Uint; + + begin + -- Range case + + if Nkind (N) = N_Range then + if not Is_Static_Expression (Low_Bound (N)) + or else + not Is_Static_Expression (High_Bound (N)) + then + raise Non_Static; + else + SLo := Expr_Value (Low_Bound (N)); + SHi := Expr_Value (High_Bound (N)); + return RList'(1 => REnt'(SLo, SHi)); + end if; + + -- Static expression case + + elsif Is_Static_Expression (N) then + Val := Expr_Value (N); + return RList'(1 => REnt'(Val, Val)); + + -- Identifier (other than static expression) case + + else pragma Assert (Nkind (N) = N_Identifier); + + -- Type case + + if Is_Type (Entity (N)) then + + -- If type has predicates, process them + + if Has_Predicates (Entity (N)) then + return Stat_Pred (Entity (N)); + + -- For static subtype without predicates, get range + + elsif Is_Static_Subtype (Entity (N)) then + SLo := Expr_Value (Type_Low_Bound (Entity (N))); + SHi := Expr_Value (Type_High_Bound (Entity (N))); + return RList'(1 => REnt'(SLo, SHi)); + + -- Any other type makes us non-static + + else + raise Non_Static; + end if; + + -- Any other kind of identifier in predicate (e.g. a non-static + -- expression value) means this is not a static predicate. + + else + raise Non_Static; + end if; + end if; + end Membership_Entry; + + --------------- + -- Stat_Pred -- + --------------- + + function Stat_Pred (Typ : Entity_Id) return RList is + begin + -- Not static if type does not have static predicates + + if not Has_Predicates (Typ) + or else No (Static_Predicate (Typ)) + then + raise Non_Static; + end if; + + -- Otherwise we convert the predicate list to a range list + + declare + Result : RList (1 .. List_Length (Static_Predicate (Typ))); + P : Node_Id; + + begin + P := First (Static_Predicate (Typ)); + for J in Result'Range loop + Result (J) := REnt'(Lo_Val (P), Hi_Val (P)); + Next (P); + end loop; + + return Result; + end; + end Stat_Pred; + + -- Start of processing for Build_Static_Predicate + + begin + -- Now analyze the expression to see if it is a static predicate + + declare + Ranges : constant RList := Get_RList (Expr); + -- Range list from expression if it is static + + Plist : List_Id; + + begin + -- Convert range list into a form for the static predicate. In the + -- Ranges array, we just have raw ranges, these must be converted + -- to properly typed and analyzed static expressions or range nodes. + + -- Note: here we limit ranges to the ranges of the subtype, so that + -- a predicate is always false for values outside the subtype. That + -- seems fine, such values are invalid anyway, and considering them + -- to fail the predicate seems allowed and friendly, and furthermore + -- simplifies processing for case statements and loops. + + Plist := New_List; + + for J in Ranges'Range loop + declare + Lo : Uint := Ranges (J).Lo; + Hi : Uint := Ranges (J).Hi; + + begin + -- Ignore completely out of range entry + + if Hi < TLo or else Lo > THi then + null; + + -- Otherwise process entry + + else + -- Adjust out of range value to subtype range + + if Lo < TLo then + Lo := TLo; + end if; + + if Hi > THi then + Hi := THi; + end if; + + -- Convert range into required form + + if Lo = Hi then + Append_To (Plist, Build_Val (Lo)); + else + Append_To (Plist, Build_Range (Lo, Hi)); + end if; + end if; + end; + end loop; + + -- Processing was successful and all entries were static, so now we + -- can store the result as the predicate list. + + Set_Static_Predicate (Typ, Plist); + + -- The processing for static predicates put the expression into + -- canonical form as a series of ranges. It also eliminated + -- duplicates and collapsed and combined ranges. We might as well + -- replace the alternatives list of the right operand of the + -- membership test with the static predicate list, which will + -- usually be more efficient. + + declare + New_Alts : constant List_Id := New_List; + Old_Node : Node_Id; + New_Node : Node_Id; + + begin + Old_Node := First (Plist); + while Present (Old_Node) loop + New_Node := New_Copy (Old_Node); + + if Nkind (New_Node) = N_Range then + Set_Low_Bound (New_Node, New_Copy (Low_Bound (Old_Node))); + Set_High_Bound (New_Node, New_Copy (High_Bound (Old_Node))); + end if; + + Append_To (New_Alts, New_Node); + Next (Old_Node); + end loop; + + -- If empty list, replace by False + + if Is_Empty_List (New_Alts) then + Rewrite (Expr, New_Occurrence_Of (Standard_False, Loc)); + + -- Else replace by set membership test + + else + Rewrite (Expr, + Make_In (Loc, + Left_Opnd => Make_Identifier (Loc, Nam), + Right_Opnd => Empty, + Alternatives => New_Alts)); + + -- Resolve new expression in function context + + Install_Formals (Predicate_Function (Typ)); + Push_Scope (Predicate_Function (Typ)); + Analyze_And_Resolve (Expr, Standard_Boolean); + Pop_Scope; + end if; + end; + end; + + -- If non-static, return doing nothing + + exception + when Non_Static => + return; + end Build_Static_Predicate; + + ----------------------------------- + -- Check_Constant_Address_Clause -- + ----------------------------------- + + procedure Check_Constant_Address_Clause + (Expr : Node_Id; + U_Ent : Entity_Id) + is + procedure Check_At_Constant_Address (Nod : Node_Id); + -- Checks that the given node N represents a name whose 'Address is + -- constant (in the same sense as OK_Constant_Address_Clause, i.e. the + -- address value is the same at the point of declaration of U_Ent and at + -- the time of elaboration of the address clause. + + procedure Check_Expr_Constants (Nod : Node_Id); + -- Checks that Nod meets the requirements for a constant address clause + -- in the sense of the enclosing procedure. + + procedure Check_List_Constants (Lst : List_Id); + -- Check that all elements of list Lst meet the requirements for a + -- constant address clause in the sense of the enclosing procedure. + + ------------------------------- + -- Check_At_Constant_Address -- + ------------------------------- + + procedure Check_At_Constant_Address (Nod : Node_Id) is + begin + if Is_Entity_Name (Nod) then + if Present (Address_Clause (Entity ((Nod)))) then + Error_Msg_NE + ("invalid address clause for initialized object &!", + Nod, U_Ent); + Error_Msg_NE + ("address for& cannot" & + " depend on another address clause! (RM 13.1(22))!", + Nod, U_Ent); + + elsif In_Same_Source_Unit (Entity (Nod), U_Ent) + and then Sloc (U_Ent) < Sloc (Entity (Nod)) + then + Error_Msg_NE + ("invalid address clause for initialized object &!", + Nod, U_Ent); + Error_Msg_Node_2 := U_Ent; + Error_Msg_NE + ("\& must be defined before & (RM 13.1(22))!", + Nod, Entity (Nod)); + end if; + + elsif Nkind (Nod) = N_Selected_Component then + declare + T : constant Entity_Id := Etype (Prefix (Nod)); + + begin + if (Is_Record_Type (T) + and then Has_Discriminants (T)) + or else + (Is_Access_Type (T) + and then Is_Record_Type (Designated_Type (T)) + and then Has_Discriminants (Designated_Type (T))) + then + Error_Msg_NE + ("invalid address clause for initialized object &!", + Nod, U_Ent); + Error_Msg_N + ("\address cannot depend on component" & + " of discriminated record (RM 13.1(22))!", + Nod); + else + Check_At_Constant_Address (Prefix (Nod)); + end if; + end; + + elsif Nkind (Nod) = N_Indexed_Component then + Check_At_Constant_Address (Prefix (Nod)); + Check_List_Constants (Expressions (Nod)); + + else + Check_Expr_Constants (Nod); + end if; + end Check_At_Constant_Address; + + -------------------------- + -- Check_Expr_Constants -- + -------------------------- + + procedure Check_Expr_Constants (Nod : Node_Id) is + Loc_U_Ent : constant Source_Ptr := Sloc (U_Ent); + Ent : Entity_Id := Empty; + + begin + if Nkind (Nod) in N_Has_Etype + and then Etype (Nod) = Any_Type + then + return; + end if; + + case Nkind (Nod) is + when N_Empty | N_Error => + return; + + when N_Identifier | N_Expanded_Name => + Ent := Entity (Nod); + + -- We need to look at the original node if it is different + -- from the node, since we may have rewritten things and + -- substituted an identifier representing the rewrite. + + if Original_Node (Nod) /= Nod then + Check_Expr_Constants (Original_Node (Nod)); + + -- If the node is an object declaration without initial + -- value, some code has been expanded, and the expression + -- is not constant, even if the constituents might be + -- acceptable, as in A'Address + offset. + + if Ekind (Ent) = E_Variable + and then + Nkind (Declaration_Node (Ent)) = N_Object_Declaration + and then + No (Expression (Declaration_Node (Ent))) + then + Error_Msg_NE + ("invalid address clause for initialized object &!", + Nod, U_Ent); + + -- If entity is constant, it may be the result of expanding + -- a check. We must verify that its declaration appears + -- before the object in question, else we also reject the + -- address clause. + + elsif Ekind (Ent) = E_Constant + and then In_Same_Source_Unit (Ent, U_Ent) + and then Sloc (Ent) > Loc_U_Ent + then + Error_Msg_NE + ("invalid address clause for initialized object &!", + Nod, U_Ent); + end if; + + return; + end if; + + -- Otherwise look at the identifier and see if it is OK + + if Ekind_In (Ent, E_Named_Integer, E_Named_Real) + or else Is_Type (Ent) + then + return; + + elsif + Ekind (Ent) = E_Constant + or else + Ekind (Ent) = E_In_Parameter + then + -- This is the case where we must have Ent defined before + -- U_Ent. Clearly if they are in different units this + -- requirement is met since the unit containing Ent is + -- already processed. + + if not In_Same_Source_Unit (Ent, U_Ent) then + return; + + -- Otherwise location of Ent must be before the location + -- of U_Ent, that's what prior defined means. + + elsif Sloc (Ent) < Loc_U_Ent then + return; + + else + Error_Msg_NE + ("invalid address clause for initialized object &!", + Nod, U_Ent); + Error_Msg_Node_2 := U_Ent; + Error_Msg_NE + ("\& must be defined before & (RM 13.1(22))!", + Nod, Ent); + end if; + + elsif Nkind (Original_Node (Nod)) = N_Function_Call then + Check_Expr_Constants (Original_Node (Nod)); + + else + Error_Msg_NE + ("invalid address clause for initialized object &!", + Nod, U_Ent); + + if Comes_From_Source (Ent) then + Error_Msg_NE + ("\reference to variable& not allowed" + & " (RM 13.1(22))!", Nod, Ent); + else + Error_Msg_N + ("non-static expression not allowed" + & " (RM 13.1(22))!", Nod); + end if; + end if; + + when N_Integer_Literal => + + -- If this is a rewritten unchecked conversion, in a system + -- where Address is an integer type, always use the base type + -- for a literal value. This is user-friendly and prevents + -- order-of-elaboration issues with instances of unchecked + -- conversion. + + if Nkind (Original_Node (Nod)) = N_Function_Call then + Set_Etype (Nod, Base_Type (Etype (Nod))); + end if; + + when N_Real_Literal | + N_String_Literal | + N_Character_Literal => + return; + + when N_Range => + Check_Expr_Constants (Low_Bound (Nod)); + Check_Expr_Constants (High_Bound (Nod)); + + when N_Explicit_Dereference => + Check_Expr_Constants (Prefix (Nod)); + + when N_Indexed_Component => + Check_Expr_Constants (Prefix (Nod)); + Check_List_Constants (Expressions (Nod)); + + when N_Slice => + Check_Expr_Constants (Prefix (Nod)); + Check_Expr_Constants (Discrete_Range (Nod)); + + when N_Selected_Component => + Check_Expr_Constants (Prefix (Nod)); + + when N_Attribute_Reference => + if Attribute_Name (Nod) = Name_Address + or else + Attribute_Name (Nod) = Name_Access + or else + Attribute_Name (Nod) = Name_Unchecked_Access + or else + Attribute_Name (Nod) = Name_Unrestricted_Access + then + Check_At_Constant_Address (Prefix (Nod)); + + else + Check_Expr_Constants (Prefix (Nod)); + Check_List_Constants (Expressions (Nod)); + end if; + + when N_Aggregate => + Check_List_Constants (Component_Associations (Nod)); + Check_List_Constants (Expressions (Nod)); + + when N_Component_Association => + Check_Expr_Constants (Expression (Nod)); + + when N_Extension_Aggregate => + Check_Expr_Constants (Ancestor_Part (Nod)); + Check_List_Constants (Component_Associations (Nod)); + Check_List_Constants (Expressions (Nod)); + + when N_Null => + return; + + when N_Binary_Op | N_Short_Circuit | N_Membership_Test => + Check_Expr_Constants (Left_Opnd (Nod)); + Check_Expr_Constants (Right_Opnd (Nod)); + + when N_Unary_Op => + Check_Expr_Constants (Right_Opnd (Nod)); + + when N_Type_Conversion | + N_Qualified_Expression | + N_Allocator => + Check_Expr_Constants (Expression (Nod)); + + when N_Unchecked_Type_Conversion => + Check_Expr_Constants (Expression (Nod)); + + -- If this is a rewritten unchecked conversion, subtypes in + -- this node are those created within the instance. To avoid + -- order of elaboration issues, replace them with their base + -- types. Note that address clauses can cause order of + -- elaboration problems because they are elaborated by the + -- back-end at the point of definition, and may mention + -- entities declared in between (as long as everything is + -- static). It is user-friendly to allow unchecked conversions + -- in this context. + + if Nkind (Original_Node (Nod)) = N_Function_Call then + Set_Etype (Expression (Nod), + Base_Type (Etype (Expression (Nod)))); + Set_Etype (Nod, Base_Type (Etype (Nod))); + end if; + + when N_Function_Call => + if not Is_Pure (Entity (Name (Nod))) then + Error_Msg_NE + ("invalid address clause for initialized object &!", + Nod, U_Ent); + + Error_Msg_NE + ("\function & is not pure (RM 13.1(22))!", + Nod, Entity (Name (Nod))); + + else + Check_List_Constants (Parameter_Associations (Nod)); + end if; + + when N_Parameter_Association => + Check_Expr_Constants (Explicit_Actual_Parameter (Nod)); + + when others => + Error_Msg_NE + ("invalid address clause for initialized object &!", + Nod, U_Ent); + Error_Msg_NE + ("\must be constant defined before& (RM 13.1(22))!", + Nod, U_Ent); + end case; + end Check_Expr_Constants; + + -------------------------- + -- Check_List_Constants -- + -------------------------- + + procedure Check_List_Constants (Lst : List_Id) is + Nod1 : Node_Id; + + begin + if Present (Lst) then + Nod1 := First (Lst); + while Present (Nod1) loop + Check_Expr_Constants (Nod1); + Next (Nod1); + end loop; + end if; + end Check_List_Constants; + + -- Start of processing for Check_Constant_Address_Clause + + begin + -- If rep_clauses are to be ignored, no need for legality checks. In + -- particular, no need to pester user about rep clauses that violate + -- the rule on constant addresses, given that these clauses will be + -- removed by Freeze before they reach the back end. + + if not Ignore_Rep_Clauses then + Check_Expr_Constants (Expr); + end if; + end Check_Constant_Address_Clause; + + ---------------------------------------- + -- Check_Record_Representation_Clause -- + ---------------------------------------- + + procedure Check_Record_Representation_Clause (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Ident : constant Node_Id := Identifier (N); + Rectype : Entity_Id; + Fent : Entity_Id; + CC : Node_Id; + Fbit : Uint; + Lbit : Uint; + Hbit : Uint := Uint_0; + Comp : Entity_Id; + Pcomp : Entity_Id; + + Max_Bit_So_Far : Uint; + -- Records the maximum bit position so far. If all field positions + -- are monotonically increasing, then we can skip the circuit for + -- checking for overlap, since no overlap is possible. + + Tagged_Parent : Entity_Id := Empty; + -- This is set in the case of a derived tagged type for which we have + -- Is_Fully_Repped_Tagged_Type True (indicating that all components are + -- positioned by record representation clauses). In this case we must + -- check for overlap between components of this tagged type, and the + -- components of its parent. Tagged_Parent will point to this parent + -- type. For all other cases Tagged_Parent is left set to Empty. + + Parent_Last_Bit : Uint; + -- Relevant only if Tagged_Parent is set, Parent_Last_Bit indicates the + -- last bit position for any field in the parent type. We only need to + -- check overlap for fields starting below this point. + + Overlap_Check_Required : Boolean; + -- Used to keep track of whether or not an overlap check is required + + Overlap_Detected : Boolean := False; + -- Set True if an overlap is detected + + Ccount : Natural := 0; + -- Number of component clauses in record rep clause + + procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id); + -- Given two entities for record components or discriminants, checks + -- if they have overlapping component clauses and issues errors if so. + + procedure Find_Component; + -- Finds component entity corresponding to current component clause (in + -- CC), and sets Comp to the entity, and Fbit/Lbit to the zero origin + -- start/stop bits for the field. If there is no matching component or + -- if the matching component does not have a component clause, then + -- that's an error and Comp is set to Empty, but no error message is + -- issued, since the message was already given. Comp is also set to + -- Empty if the current "component clause" is in fact a pragma. + + ----------------------------- + -- Check_Component_Overlap -- + ----------------------------- + + procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id) is + CC1 : constant Node_Id := Component_Clause (C1_Ent); + CC2 : constant Node_Id := Component_Clause (C2_Ent); + + begin + if Present (CC1) and then Present (CC2) then + + -- Exclude odd case where we have two tag fields in the same + -- record, both at location zero. This seems a bit strange, but + -- it seems to happen in some circumstances, perhaps on an error. + + if Chars (C1_Ent) = Name_uTag + and then + Chars (C2_Ent) = Name_uTag + then + return; + end if; + + -- Here we check if the two fields overlap + + declare + S1 : constant Uint := Component_Bit_Offset (C1_Ent); + S2 : constant Uint := Component_Bit_Offset (C2_Ent); + E1 : constant Uint := S1 + Esize (C1_Ent); + E2 : constant Uint := S2 + Esize (C2_Ent); + + begin + if E2 <= S1 or else E1 <= S2 then + null; + else + Error_Msg_Node_2 := Component_Name (CC2); + Error_Msg_Sloc := Sloc (Error_Msg_Node_2); + Error_Msg_Node_1 := Component_Name (CC1); + Error_Msg_N + ("component& overlaps & #", Component_Name (CC1)); + Overlap_Detected := True; + end if; + end; + end if; + end Check_Component_Overlap; + + -------------------- + -- Find_Component -- + -------------------- + + procedure Find_Component is + + procedure Search_Component (R : Entity_Id); + -- Search components of R for a match. If found, Comp is set. + + ---------------------- + -- Search_Component -- + ---------------------- + + procedure Search_Component (R : Entity_Id) is + begin + Comp := First_Component_Or_Discriminant (R); + while Present (Comp) loop + + -- Ignore error of attribute name for component name (we + -- already gave an error message for this, so no need to + -- complain here) + + if Nkind (Component_Name (CC)) = N_Attribute_Reference then + null; + else + exit when Chars (Comp) = Chars (Component_Name (CC)); + end if; + + Next_Component_Or_Discriminant (Comp); + end loop; + end Search_Component; + + -- Start of processing for Find_Component + + begin + -- Return with Comp set to Empty if we have a pragma + + if Nkind (CC) = N_Pragma then + Comp := Empty; + return; + end if; + + -- Search current record for matching component + + Search_Component (Rectype); + + -- If not found, maybe component of base type that is absent from + -- statically constrained first subtype. + + if No (Comp) then + Search_Component (Base_Type (Rectype)); + end if; + + -- If no component, or the component does not reference the component + -- clause in question, then there was some previous error for which + -- we already gave a message, so just return with Comp Empty. + + if No (Comp) + or else Component_Clause (Comp) /= CC + then + Comp := Empty; + + -- Normal case where we have a component clause + + else + Fbit := Component_Bit_Offset (Comp); + Lbit := Fbit + Esize (Comp) - 1; + end if; + end Find_Component; + + -- Start of processing for Check_Record_Representation_Clause + + begin + Find_Type (Ident); + Rectype := Entity (Ident); + + if Rectype = Any_Type then + return; + else + Rectype := Underlying_Type (Rectype); + end if; + + -- See if we have a fully repped derived tagged type + + declare + PS : constant Entity_Id := Parent_Subtype (Rectype); + + begin + if Present (PS) and then Is_Fully_Repped_Tagged_Type (PS) then + Tagged_Parent := PS; + + -- Find maximum bit of any component of the parent type + + Parent_Last_Bit := UI_From_Int (System_Address_Size - 1); + Pcomp := First_Entity (Tagged_Parent); + while Present (Pcomp) loop + if Ekind_In (Pcomp, E_Discriminant, E_Component) then + if Component_Bit_Offset (Pcomp) /= No_Uint + and then Known_Static_Esize (Pcomp) + then + Parent_Last_Bit := + UI_Max + (Parent_Last_Bit, + Component_Bit_Offset (Pcomp) + Esize (Pcomp) - 1); + end if; + + Next_Entity (Pcomp); + end if; + end loop; + end if; + end; + + -- All done if no component clauses + + CC := First (Component_Clauses (N)); + + if No (CC) then + return; + end if; + + -- If a tag is present, then create a component clause that places it + -- at the start of the record (otherwise gigi may place it after other + -- fields that have rep clauses). + + Fent := First_Entity (Rectype); + + if Nkind (Fent) = N_Defining_Identifier + and then Chars (Fent) = Name_uTag + then + Set_Component_Bit_Offset (Fent, Uint_0); + Set_Normalized_Position (Fent, Uint_0); + Set_Normalized_First_Bit (Fent, Uint_0); + Set_Normalized_Position_Max (Fent, Uint_0); + Init_Esize (Fent, System_Address_Size); + + Set_Component_Clause (Fent, + Make_Component_Clause (Loc, + Component_Name => Make_Identifier (Loc, Name_uTag), + + Position => Make_Integer_Literal (Loc, Uint_0), + First_Bit => Make_Integer_Literal (Loc, Uint_0), + Last_Bit => + Make_Integer_Literal (Loc, + UI_From_Int (System_Address_Size)))); + + Ccount := Ccount + 1; + end if; + + Max_Bit_So_Far := Uint_Minus_1; + Overlap_Check_Required := False; + + -- Process the component clauses + + while Present (CC) loop + Find_Component; + + if Present (Comp) then + Ccount := Ccount + 1; + + -- We need a full overlap check if record positions non-monotonic + + if Fbit <= Max_Bit_So_Far then + Overlap_Check_Required := True; + end if; + + Max_Bit_So_Far := Lbit; + + -- Check bit position out of range of specified size + + if Has_Size_Clause (Rectype) + and then Esize (Rectype) <= Lbit + then + Error_Msg_N + ("bit number out of range of specified size", + Last_Bit (CC)); + + -- Check for overlap with tag field + + else + if Is_Tagged_Type (Rectype) + and then Fbit < System_Address_Size + then + Error_Msg_NE + ("component overlaps tag field of&", + Component_Name (CC), Rectype); + Overlap_Detected := True; + end if; + + if Hbit < Lbit then + Hbit := Lbit; + end if; + end if; + + -- Check parent overlap if component might overlap parent field + + if Present (Tagged_Parent) + and then Fbit <= Parent_Last_Bit + then + Pcomp := First_Component_Or_Discriminant (Tagged_Parent); + while Present (Pcomp) loop + if not Is_Tag (Pcomp) + and then Chars (Pcomp) /= Name_uParent + then + Check_Component_Overlap (Comp, Pcomp); + end if; + + Next_Component_Or_Discriminant (Pcomp); + end loop; + end if; + end if; + + Next (CC); + end loop; + + -- Now that we have processed all the component clauses, check for + -- overlap. We have to leave this till last, since the components can + -- appear in any arbitrary order in the representation clause. + + -- We do not need this check if all specified ranges were monotonic, + -- as recorded by Overlap_Check_Required being False at this stage. + + -- This first section checks if there are any overlapping entries at + -- all. It does this by sorting all entries and then seeing if there are + -- any overlaps. If there are none, then that is decisive, but if there + -- are overlaps, they may still be OK (they may result from fields in + -- different variants). + + if Overlap_Check_Required then + Overlap_Check1 : declare + + OC_Fbit : array (0 .. Ccount) of Uint; + -- First-bit values for component clauses, the value is the offset + -- of the first bit of the field from start of record. The zero + -- entry is for use in sorting. + + OC_Lbit : array (0 .. Ccount) of Uint; + -- Last-bit values for component clauses, the value is the offset + -- of the last bit of the field from start of record. The zero + -- entry is for use in sorting. + + OC_Count : Natural := 0; + -- Count of entries in OC_Fbit and OC_Lbit + + function OC_Lt (Op1, Op2 : Natural) return Boolean; + -- Compare routine for Sort + + procedure OC_Move (From : Natural; To : Natural); + -- Move routine for Sort + + package Sorting is new GNAT.Heap_Sort_G (OC_Move, OC_Lt); + + ----------- + -- OC_Lt -- + ----------- + + function OC_Lt (Op1, Op2 : Natural) return Boolean is + begin + return OC_Fbit (Op1) < OC_Fbit (Op2); + end OC_Lt; + + ------------- + -- OC_Move -- + ------------- + + procedure OC_Move (From : Natural; To : Natural) is + begin + OC_Fbit (To) := OC_Fbit (From); + OC_Lbit (To) := OC_Lbit (From); + end OC_Move; + + -- Start of processing for Overlap_Check + + begin + CC := First (Component_Clauses (N)); + while Present (CC) loop + + -- Exclude component clause already marked in error + + if not Error_Posted (CC) then + Find_Component; + + if Present (Comp) then + OC_Count := OC_Count + 1; + OC_Fbit (OC_Count) := Fbit; + OC_Lbit (OC_Count) := Lbit; + end if; + end if; + + Next (CC); + end loop; + + Sorting.Sort (OC_Count); + + Overlap_Check_Required := False; + for J in 1 .. OC_Count - 1 loop + if OC_Lbit (J) >= OC_Fbit (J + 1) then + Overlap_Check_Required := True; + exit; + end if; + end loop; + end Overlap_Check1; + end if; + + -- If Overlap_Check_Required is still True, then we have to do the full + -- scale overlap check, since we have at least two fields that do + -- overlap, and we need to know if that is OK since they are in + -- different variant, or whether we have a definite problem. + + if Overlap_Check_Required then + Overlap_Check2 : declare + C1_Ent, C2_Ent : Entity_Id; + -- Entities of components being checked for overlap + + Clist : Node_Id; + -- Component_List node whose Component_Items are being checked + + Citem : Node_Id; + -- Component declaration for component being checked + + begin + C1_Ent := First_Entity (Base_Type (Rectype)); + + -- Loop through all components in record. For each component check + -- for overlap with any of the preceding elements on the component + -- list containing the component and also, if the component is in + -- a variant, check against components outside the case structure. + -- This latter test is repeated recursively up the variant tree. + + Main_Component_Loop : while Present (C1_Ent) loop + if not Ekind_In (C1_Ent, E_Component, E_Discriminant) then + goto Continue_Main_Component_Loop; + end if; + + -- Skip overlap check if entity has no declaration node. This + -- happens with discriminants in constrained derived types. + -- Possibly we are missing some checks as a result, but that + -- does not seem terribly serious. + + if No (Declaration_Node (C1_Ent)) then + goto Continue_Main_Component_Loop; + end if; + + Clist := Parent (List_Containing (Declaration_Node (C1_Ent))); + + -- Loop through component lists that need checking. Check the + -- current component list and all lists in variants above us. + + Component_List_Loop : loop + + -- If derived type definition, go to full declaration + -- If at outer level, check discriminants if there are any. + + if Nkind (Clist) = N_Derived_Type_Definition then + Clist := Parent (Clist); + end if; + + -- Outer level of record definition, check discriminants + + if Nkind_In (Clist, N_Full_Type_Declaration, + N_Private_Type_Declaration) + then + if Has_Discriminants (Defining_Identifier (Clist)) then + C2_Ent := + First_Discriminant (Defining_Identifier (Clist)); + while Present (C2_Ent) loop + exit when C1_Ent = C2_Ent; + Check_Component_Overlap (C1_Ent, C2_Ent); + Next_Discriminant (C2_Ent); + end loop; + end if; + + -- Record extension case + + elsif Nkind (Clist) = N_Derived_Type_Definition then + Clist := Empty; + + -- Otherwise check one component list + + else + Citem := First (Component_Items (Clist)); + while Present (Citem) loop + if Nkind (Citem) = N_Component_Declaration then + C2_Ent := Defining_Identifier (Citem); + exit when C1_Ent = C2_Ent; + Check_Component_Overlap (C1_Ent, C2_Ent); + end if; + + Next (Citem); + end loop; + end if; + + -- Check for variants above us (the parent of the Clist can + -- be a variant, in which case its parent is a variant part, + -- and the parent of the variant part is a component list + -- whose components must all be checked against the current + -- component for overlap). + + if Nkind (Parent (Clist)) = N_Variant then + Clist := Parent (Parent (Parent (Clist))); + + -- Check for possible discriminant part in record, this + -- is treated essentially as another level in the + -- recursion. For this case the parent of the component + -- list is the record definition, and its parent is the + -- full type declaration containing the discriminant + -- specifications. + + elsif Nkind (Parent (Clist)) = N_Record_Definition then + Clist := Parent (Parent ((Clist))); + + -- If neither of these two cases, we are at the top of + -- the tree. + + else + exit Component_List_Loop; + end if; + end loop Component_List_Loop; + + <> + Next_Entity (C1_Ent); + + end loop Main_Component_Loop; + end Overlap_Check2; + end if; + + -- The following circuit deals with warning on record holes (gaps). We + -- skip this check if overlap was detected, since it makes sense for the + -- programmer to fix this illegality before worrying about warnings. + + if not Overlap_Detected and Warn_On_Record_Holes then + Record_Hole_Check : declare + Decl : constant Node_Id := Declaration_Node (Base_Type (Rectype)); + -- Full declaration of record type + + procedure Check_Component_List + (CL : Node_Id; + Sbit : Uint; + DS : List_Id); + -- Check component list CL for holes. The starting bit should be + -- Sbit. which is zero for the main record component list and set + -- appropriately for recursive calls for variants. DS is set to + -- a list of discriminant specifications to be included in the + -- consideration of components. It is No_List if none to consider. + + -------------------------- + -- Check_Component_List -- + -------------------------- + + procedure Check_Component_List + (CL : Node_Id; + Sbit : Uint; + DS : List_Id) + is + Compl : Integer; + + begin + Compl := Integer (List_Length (Component_Items (CL))); + + if DS /= No_List then + Compl := Compl + Integer (List_Length (DS)); + end if; + + declare + Comps : array (Natural range 0 .. Compl) of Entity_Id; + -- Gather components (zero entry is for sort routine) + + Ncomps : Natural := 0; + -- Number of entries stored in Comps (starting at Comps (1)) + + Citem : Node_Id; + -- One component item or discriminant specification + + Nbit : Uint; + -- Starting bit for next component + + CEnt : Entity_Id; + -- Component entity + + Variant : Node_Id; + -- One variant + + function Lt (Op1, Op2 : Natural) return Boolean; + -- Compare routine for Sort + + procedure Move (From : Natural; To : Natural); + -- Move routine for Sort + + package Sorting is new GNAT.Heap_Sort_G (Move, Lt); + + -------- + -- Lt -- + -------- + + function Lt (Op1, Op2 : Natural) return Boolean is + begin + return Component_Bit_Offset (Comps (Op1)) + < + Component_Bit_Offset (Comps (Op2)); + end Lt; + + ---------- + -- Move -- + ---------- + + procedure Move (From : Natural; To : Natural) is + begin + Comps (To) := Comps (From); + end Move; + + begin + -- Gather discriminants into Comp + + if DS /= No_List then + Citem := First (DS); + while Present (Citem) loop + if Nkind (Citem) = N_Discriminant_Specification then + declare + Ent : constant Entity_Id := + Defining_Identifier (Citem); + begin + if Ekind (Ent) = E_Discriminant then + Ncomps := Ncomps + 1; + Comps (Ncomps) := Ent; + end if; + end; + end if; + + Next (Citem); + end loop; + end if; + + -- Gather component entities into Comp + + Citem := First (Component_Items (CL)); + while Present (Citem) loop + if Nkind (Citem) = N_Component_Declaration then + Ncomps := Ncomps + 1; + Comps (Ncomps) := Defining_Identifier (Citem); + end if; + + Next (Citem); + end loop; + + -- Now sort the component entities based on the first bit. + -- Note we already know there are no overlapping components. + + Sorting.Sort (Ncomps); + + -- Loop through entries checking for holes + + Nbit := Sbit; + for J in 1 .. Ncomps loop + CEnt := Comps (J); + Error_Msg_Uint_1 := Component_Bit_Offset (CEnt) - Nbit; + + if Error_Msg_Uint_1 > 0 then + Error_Msg_NE + ("?^-bit gap before component&", + Component_Name (Component_Clause (CEnt)), CEnt); + end if; + + Nbit := Component_Bit_Offset (CEnt) + Esize (CEnt); + end loop; + + -- Process variant parts recursively if present + + if Present (Variant_Part (CL)) then + Variant := First (Variants (Variant_Part (CL))); + while Present (Variant) loop + Check_Component_List + (Component_List (Variant), Nbit, No_List); + Next (Variant); + end loop; + end if; + end; + end Check_Component_List; + + -- Start of processing for Record_Hole_Check + + begin + declare + Sbit : Uint; + + begin + if Is_Tagged_Type (Rectype) then + Sbit := UI_From_Int (System_Address_Size); + else + Sbit := Uint_0; + end if; + + if Nkind (Decl) = N_Full_Type_Declaration + and then Nkind (Type_Definition (Decl)) = N_Record_Definition + then + Check_Component_List + (Component_List (Type_Definition (Decl)), + Sbit, + Discriminant_Specifications (Decl)); + end if; + end; + end Record_Hole_Check; + end if; + + -- For records that have component clauses for all components, and whose + -- size is less than or equal to 32, we need to know the size in the + -- front end to activate possible packed array processing where the + -- component type is a record. + + -- At this stage Hbit + 1 represents the first unused bit from all the + -- component clauses processed, so if the component clauses are + -- complete, then this is the length of the record. + + -- For records longer than System.Storage_Unit, and for those where not + -- all components have component clauses, the back end determines the + -- length (it may for example be appropriate to round up the size + -- to some convenient boundary, based on alignment considerations, etc). + + if Unknown_RM_Size (Rectype) and then Hbit + 1 <= 32 then + + -- Nothing to do if at least one component has no component clause + + Comp := First_Component_Or_Discriminant (Rectype); + while Present (Comp) loop + exit when No (Component_Clause (Comp)); + Next_Component_Or_Discriminant (Comp); + end loop; + + -- If we fall out of loop, all components have component clauses + -- and so we can set the size to the maximum value. + + if No (Comp) then + Set_RM_Size (Rectype, Hbit + 1); + end if; + end if; + end Check_Record_Representation_Clause; + + ---------------- + -- Check_Size -- + ---------------- + + procedure Check_Size + (N : Node_Id; + T : Entity_Id; + Siz : Uint; + Biased : out Boolean) + is + UT : constant Entity_Id := Underlying_Type (T); + M : Uint; + + begin + Biased := False; + + -- Dismiss cases for generic types or types with previous errors + + if No (UT) + or else UT = Any_Type + or else Is_Generic_Type (UT) + or else Is_Generic_Type (Root_Type (UT)) + then + return; + + -- Check case of bit packed array + + elsif Is_Array_Type (UT) + and then Known_Static_Component_Size (UT) + and then Is_Bit_Packed_Array (UT) + then + declare + Asiz : Uint; + Indx : Node_Id; + Ityp : Entity_Id; + + begin + Asiz := Component_Size (UT); + Indx := First_Index (UT); + loop + Ityp := Etype (Indx); + + -- If non-static bound, then we are not in the business of + -- trying to check the length, and indeed an error will be + -- issued elsewhere, since sizes of non-static array types + -- cannot be set implicitly or explicitly. + + if not Is_Static_Subtype (Ityp) then + return; + end if; + + -- Otherwise accumulate next dimension + + Asiz := Asiz * (Expr_Value (Type_High_Bound (Ityp)) - + Expr_Value (Type_Low_Bound (Ityp)) + + Uint_1); + + Next_Index (Indx); + exit when No (Indx); + end loop; + + if Asiz <= Siz then + return; + else + Error_Msg_Uint_1 := Asiz; + Error_Msg_NE + ("size for& too small, minimum allowed is ^", N, T); + Set_Esize (T, Asiz); + Set_RM_Size (T, Asiz); + end if; + end; + + -- All other composite types are ignored + + elsif Is_Composite_Type (UT) then + return; + + -- For fixed-point types, don't check minimum if type is not frozen, + -- since we don't know all the characteristics of the type that can + -- affect the size (e.g. a specified small) till freeze time. + + elsif Is_Fixed_Point_Type (UT) + and then not Is_Frozen (UT) + then + null; + + -- Cases for which a minimum check is required + + else + -- Ignore if specified size is correct for the type + + if Known_Esize (UT) and then Siz = Esize (UT) then + return; + end if; + + -- Otherwise get minimum size + + M := UI_From_Int (Minimum_Size (UT)); + + if Siz < M then + + -- Size is less than minimum size, but one possibility remains + -- that we can manage with the new size if we bias the type. + + M := UI_From_Int (Minimum_Size (UT, Biased => True)); + + if Siz < M then + Error_Msg_Uint_1 := M; + Error_Msg_NE + ("size for& too small, minimum allowed is ^", N, T); + Set_Esize (T, M); + Set_RM_Size (T, M); + else + Biased := True; + end if; + end if; + end if; + end Check_Size; + + ------------------------- + -- Get_Alignment_Value -- + ------------------------- + + function Get_Alignment_Value (Expr : Node_Id) return Uint is + Align : constant Uint := Static_Integer (Expr); + + begin + if Align = No_Uint then + return No_Uint; + + elsif Align <= 0 then + Error_Msg_N ("alignment value must be positive", Expr); + return No_Uint; + + else + for J in Int range 0 .. 64 loop + declare + M : constant Uint := Uint_2 ** J; + + begin + exit when M = Align; + + if M > Align then + Error_Msg_N + ("alignment value must be power of 2", Expr); + return No_Uint; + end if; + end; + end loop; + + return Align; + end if; + end Get_Alignment_Value; + + ---------------- + -- Initialize -- + ---------------- + + procedure Initialize is + begin + Address_Clause_Checks.Init; + Independence_Checks.Init; + Unchecked_Conversions.Init; + end Initialize; + + ------------------------- + -- Is_Operational_Item -- + ------------------------- + + function Is_Operational_Item (N : Node_Id) return Boolean is + begin + if Nkind (N) /= N_Attribute_Definition_Clause then + return False; + else + declare + Id : constant Attribute_Id := Get_Attribute_Id (Chars (N)); + begin + return Id = Attribute_Input + or else Id = Attribute_Output + or else Id = Attribute_Read + or else Id = Attribute_Write + or else Id = Attribute_External_Tag; + end; + end if; + end Is_Operational_Item; + + ------------------ + -- Minimum_Size -- + ------------------ + + function Minimum_Size + (T : Entity_Id; + Biased : Boolean := False) return Nat + is + Lo : Uint := No_Uint; + Hi : Uint := No_Uint; + LoR : Ureal := No_Ureal; + HiR : Ureal := No_Ureal; + LoSet : Boolean := False; + HiSet : Boolean := False; + B : Uint; + S : Nat; + Ancest : Entity_Id; + R_Typ : constant Entity_Id := Root_Type (T); + + begin + -- If bad type, return 0 + + if T = Any_Type then + return 0; + + -- For generic types, just return zero. There cannot be any legitimate + -- need to know such a size, but this routine may be called with a + -- generic type as part of normal processing. + + elsif Is_Generic_Type (R_Typ) + or else R_Typ = Any_Type + then + return 0; + + -- Access types. Normally an access type cannot have a size smaller + -- than the size of System.Address. The exception is on VMS, where + -- we have short and long addresses, and it is possible for an access + -- type to have a short address size (and thus be less than the size + -- of System.Address itself). We simply skip the check for VMS, and + -- leave it to the back end to do the check. + + elsif Is_Access_Type (T) then + if OpenVMS_On_Target then + return 0; + else + return System_Address_Size; + end if; + + -- Floating-point types + + elsif Is_Floating_Point_Type (T) then + return UI_To_Int (Esize (R_Typ)); + + -- Discrete types + + elsif Is_Discrete_Type (T) then + + -- The following loop is looking for the nearest compile time known + -- bounds following the ancestor subtype chain. The idea is to find + -- the most restrictive known bounds information. + + Ancest := T; + loop + if Ancest = Any_Type or else Etype (Ancest) = Any_Type then + return 0; + end if; + + if not LoSet then + if Compile_Time_Known_Value (Type_Low_Bound (Ancest)) then + Lo := Expr_Rep_Value (Type_Low_Bound (Ancest)); + LoSet := True; + exit when HiSet; + end if; + end if; + + if not HiSet then + if Compile_Time_Known_Value (Type_High_Bound (Ancest)) then + Hi := Expr_Rep_Value (Type_High_Bound (Ancest)); + HiSet := True; + exit when LoSet; + end if; + end if; + + Ancest := Ancestor_Subtype (Ancest); + + if No (Ancest) then + Ancest := Base_Type (T); + + if Is_Generic_Type (Ancest) then + return 0; + end if; + end if; + end loop; + + -- Fixed-point types. We can't simply use Expr_Value to get the + -- Corresponding_Integer_Value values of the bounds, since these do not + -- get set till the type is frozen, and this routine can be called + -- before the type is frozen. Similarly the test for bounds being static + -- needs to include the case where we have unanalyzed real literals for + -- the same reason. + + elsif Is_Fixed_Point_Type (T) then + + -- The following loop is looking for the nearest compile time known + -- bounds following the ancestor subtype chain. The idea is to find + -- the most restrictive known bounds information. + + Ancest := T; + loop + if Ancest = Any_Type or else Etype (Ancest) = Any_Type then + return 0; + end if; + + -- Note: In the following two tests for LoSet and HiSet, it may + -- seem redundant to test for N_Real_Literal here since normally + -- one would assume that the test for the value being known at + -- compile time includes this case. However, there is a glitch. + -- If the real literal comes from folding a non-static expression, + -- then we don't consider any non- static expression to be known + -- at compile time if we are in configurable run time mode (needed + -- in some cases to give a clearer definition of what is and what + -- is not accepted). So the test is indeed needed. Without it, we + -- would set neither Lo_Set nor Hi_Set and get an infinite loop. + + if not LoSet then + if Nkind (Type_Low_Bound (Ancest)) = N_Real_Literal + or else Compile_Time_Known_Value (Type_Low_Bound (Ancest)) + then + LoR := Expr_Value_R (Type_Low_Bound (Ancest)); + LoSet := True; + exit when HiSet; + end if; + end if; + + if not HiSet then + if Nkind (Type_High_Bound (Ancest)) = N_Real_Literal + or else Compile_Time_Known_Value (Type_High_Bound (Ancest)) + then + HiR := Expr_Value_R (Type_High_Bound (Ancest)); + HiSet := True; + exit when LoSet; + end if; + end if; + + Ancest := Ancestor_Subtype (Ancest); + + if No (Ancest) then + Ancest := Base_Type (T); + + if Is_Generic_Type (Ancest) then + return 0; + end if; + end if; + end loop; + + Lo := UR_To_Uint (LoR / Small_Value (T)); + Hi := UR_To_Uint (HiR / Small_Value (T)); + + -- No other types allowed + + else + raise Program_Error; + end if; + + -- Fall through with Hi and Lo set. Deal with biased case + + if (Biased + and then not Is_Fixed_Point_Type (T) + and then not (Is_Enumeration_Type (T) + and then Has_Non_Standard_Rep (T))) + or else Has_Biased_Representation (T) + then + Hi := Hi - Lo; + Lo := Uint_0; + end if; + + -- Signed case. Note that we consider types like range 1 .. -1 to be + -- signed for the purpose of computing the size, since the bounds have + -- to be accommodated in the base type. + + if Lo < 0 or else Hi < 0 then + S := 1; + B := Uint_1; + + -- S = size, B = 2 ** (size - 1) (can accommodate -B .. +(B - 1)) + -- Note that we accommodate the case where the bounds cross. This + -- can happen either because of the way the bounds are declared + -- or because of the algorithm in Freeze_Fixed_Point_Type. + + while Lo < -B + or else Hi < -B + or else Lo >= B + or else Hi >= B + loop + B := Uint_2 ** S; + S := S + 1; + end loop; + + -- Unsigned case + + else + -- If both bounds are positive, make sure that both are represen- + -- table in the case where the bounds are crossed. This can happen + -- either because of the way the bounds are declared, or because of + -- the algorithm in Freeze_Fixed_Point_Type. + + if Lo > Hi then + Hi := Lo; + end if; + + -- S = size, (can accommodate 0 .. (2**size - 1)) + + S := 0; + while Hi >= Uint_2 ** S loop + S := S + 1; + end loop; + end if; + + return S; + end Minimum_Size; + + --------------------------- + -- New_Stream_Subprogram -- + --------------------------- + + procedure New_Stream_Subprogram + (N : Node_Id; + Ent : Entity_Id; + Subp : Entity_Id; + Nam : TSS_Name_Type) + is + Loc : constant Source_Ptr := Sloc (N); + Sname : constant Name_Id := Make_TSS_Name (Base_Type (Ent), Nam); + Subp_Id : Entity_Id; + Subp_Decl : Node_Id; + F : Entity_Id; + Etyp : Entity_Id; + + Defer_Declaration : constant Boolean := + Is_Tagged_Type (Ent) or else Is_Private_Type (Ent); + -- For a tagged type, there is a declaration for each stream attribute + -- at the freeze point, and we must generate only a completion of this + -- declaration. We do the same for private types, because the full view + -- might be tagged. Otherwise we generate a declaration at the point of + -- the attribute definition clause. + + function Build_Spec return Node_Id; + -- Used for declaration and renaming declaration, so that this is + -- treated as a renaming_as_body. + + ---------------- + -- Build_Spec -- + ---------------- + + function Build_Spec return Node_Id is + Out_P : constant Boolean := (Nam = TSS_Stream_Read); + Formals : List_Id; + Spec : Node_Id; + T_Ref : constant Node_Id := New_Reference_To (Etyp, Loc); + + begin + Subp_Id := Make_Defining_Identifier (Loc, Sname); + + -- S : access Root_Stream_Type'Class + + Formals := New_List ( + Make_Parameter_Specification (Loc, + Defining_Identifier => + Make_Defining_Identifier (Loc, Name_S), + Parameter_Type => + Make_Access_Definition (Loc, + Subtype_Mark => + New_Reference_To ( + Designated_Type (Etype (F)), Loc)))); + + if Nam = TSS_Stream_Input then + Spec := Make_Function_Specification (Loc, + Defining_Unit_Name => Subp_Id, + Parameter_Specifications => Formals, + Result_Definition => T_Ref); + else + -- V : [out] T + + Append_To (Formals, + Make_Parameter_Specification (Loc, + Defining_Identifier => Make_Defining_Identifier (Loc, Name_V), + Out_Present => Out_P, + Parameter_Type => T_Ref)); + + Spec := + Make_Procedure_Specification (Loc, + Defining_Unit_Name => Subp_Id, + Parameter_Specifications => Formals); + end if; + + return Spec; + end Build_Spec; + + -- Start of processing for New_Stream_Subprogram + + begin + F := First_Formal (Subp); + + if Ekind (Subp) = E_Procedure then + Etyp := Etype (Next_Formal (F)); + else + Etyp := Etype (Subp); + end if; + + -- Prepare subprogram declaration and insert it as an action on the + -- clause node. The visibility for this entity is used to test for + -- visibility of the attribute definition clause (in the sense of + -- 8.3(23) as amended by AI-195). + + if not Defer_Declaration then + Subp_Decl := + Make_Subprogram_Declaration (Loc, + Specification => Build_Spec); + + -- For a tagged type, there is always a visible declaration for each + -- stream TSS (it is a predefined primitive operation), and the + -- completion of this declaration occurs at the freeze point, which is + -- not always visible at places where the attribute definition clause is + -- visible. So, we create a dummy entity here for the purpose of + -- tracking the visibility of the attribute definition clause itself. + + else + Subp_Id := + Make_Defining_Identifier (Loc, New_External_Name (Sname, 'V')); + Subp_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Subp_Id, + Object_Definition => New_Occurrence_Of (Standard_Boolean, Loc)); + end if; + + Insert_Action (N, Subp_Decl); + Set_Entity (N, Subp_Id); + + Subp_Decl := + Make_Subprogram_Renaming_Declaration (Loc, + Specification => Build_Spec, + Name => New_Reference_To (Subp, Loc)); + + if Defer_Declaration then + Set_TSS (Base_Type (Ent), Subp_Id); + else + Insert_Action (N, Subp_Decl); + Copy_TSS (Subp_Id, Base_Type (Ent)); + end if; + end New_Stream_Subprogram; + + ------------------------ + -- Rep_Item_Too_Early -- + ------------------------ + + function Rep_Item_Too_Early (T : Entity_Id; N : Node_Id) return Boolean is + begin + -- Cannot apply non-operational rep items to generic types + + if Is_Operational_Item (N) then + return False; + + elsif Is_Type (T) + and then Is_Generic_Type (Root_Type (T)) + then + Error_Msg_N ("representation item not allowed for generic type", N); + return True; + end if; + + -- Otherwise check for incomplete type + + if Is_Incomplete_Or_Private_Type (T) + and then No (Underlying_Type (T)) + then + Error_Msg_N + ("representation item must be after full type declaration", N); + return True; + + -- If the type has incomplete components, a representation clause is + -- illegal but stream attributes and Convention pragmas are correct. + + elsif Has_Private_Component (T) then + if Nkind (N) = N_Pragma then + return False; + else + Error_Msg_N + ("representation item must appear after type is fully defined", + N); + return True; + end if; + else + return False; + end if; + end Rep_Item_Too_Early; + + ----------------------- + -- Rep_Item_Too_Late -- + ----------------------- + + function Rep_Item_Too_Late + (T : Entity_Id; + N : Node_Id; + FOnly : Boolean := False) return Boolean + is + S : Entity_Id; + Parent_Type : Entity_Id; + + procedure Too_Late; + -- Output the too late message. Note that this is not considered a + -- serious error, since the effect is simply that we ignore the + -- representation clause in this case. + + -------------- + -- Too_Late -- + -------------- + + procedure Too_Late is + begin + Error_Msg_N ("|representation item appears too late!", N); + end Too_Late; + + -- Start of processing for Rep_Item_Too_Late + + begin + -- First make sure entity is not frozen (RM 13.1(9)). Exclude imported + -- types, which may be frozen if they appear in a representation clause + -- for a local type. + + if Is_Frozen (T) + and then not From_With_Type (T) + then + Too_Late; + S := First_Subtype (T); + + if Present (Freeze_Node (S)) then + Error_Msg_NE + ("?no more representation items for }", Freeze_Node (S), S); + end if; + + return True; + + -- Check for case of non-tagged derived type whose parent either has + -- primitive operations, or is a by reference type (RM 13.1(10)). + + elsif Is_Type (T) + and then not FOnly + and then Is_Derived_Type (T) + and then not Is_Tagged_Type (T) + then + Parent_Type := Etype (Base_Type (T)); + + if Has_Primitive_Operations (Parent_Type) then + Too_Late; + Error_Msg_NE + ("primitive operations already defined for&!", N, Parent_Type); + return True; + + elsif Is_By_Reference_Type (Parent_Type) then + Too_Late; + Error_Msg_NE + ("parent type & is a by reference type!", N, Parent_Type); + return True; + end if; + end if; + + -- No error, link item into head of chain of rep items for the entity, + -- but avoid chaining if we have an overloadable entity, and the pragma + -- is one that can apply to multiple overloaded entities. + + if Is_Overloadable (T) + and then Nkind (N) = N_Pragma + then + declare + Pname : constant Name_Id := Pragma_Name (N); + begin + if Pname = Name_Convention or else + Pname = Name_Import or else + Pname = Name_Export or else + Pname = Name_External or else + Pname = Name_Interface + then + return False; + end if; + end; + end if; + + Record_Rep_Item (T, N); + return False; + end Rep_Item_Too_Late; + + ------------------------------------- + -- Replace_Type_References_Generic -- + ------------------------------------- + + procedure Replace_Type_References_Generic (N : Node_Id; TName : Name_Id) is + + function Replace_Node (N : Node_Id) return Traverse_Result; + -- Processes a single node in the traversal procedure below, checking + -- if node N should be replaced, and if so, doing the replacement. + + procedure Replace_Type_Refs is new Traverse_Proc (Replace_Node); + -- This instantiation provides the body of Replace_Type_References + + ------------------ + -- Replace_Node -- + ------------------ + + function Replace_Node (N : Node_Id) return Traverse_Result is + S : Entity_Id; + P : Node_Id; + + begin + -- Case of identifier + + if Nkind (N) = N_Identifier then + + -- If not the type name, all done with this node + + if Chars (N) /= TName then + return Skip; + + -- Otherwise do the replacement and we are done with this node + + else + Replace_Type_Reference (N); + return Skip; + end if; + + -- Case of selected component (which is what a qualification + -- looks like in the unanalyzed tree, which is what we have. + + elsif Nkind (N) = N_Selected_Component then + + -- If selector name is not our type, keeping going (we might + -- still have an occurrence of the type in the prefix). + + if Nkind (Selector_Name (N)) /= N_Identifier + or else Chars (Selector_Name (N)) /= TName + then + return OK; + + -- Selector name is our type, check qualification + + else + -- Loop through scopes and prefixes, doing comparison + + S := Current_Scope; + P := Prefix (N); + loop + -- Continue if no more scopes or scope with no name + + if No (S) or else Nkind (S) not in N_Has_Chars then + return OK; + end if; + + -- Do replace if prefix is an identifier matching the + -- scope that we are currently looking at. + + if Nkind (P) = N_Identifier + and then Chars (P) = Chars (S) + then + Replace_Type_Reference (N); + return Skip; + end if; + + -- Go check scope above us if prefix is itself of the + -- form of a selected component, whose selector matches + -- the scope we are currently looking at. + + if Nkind (P) = N_Selected_Component + and then Nkind (Selector_Name (P)) = N_Identifier + and then Chars (Selector_Name (P)) = Chars (S) + then + S := Scope (S); + P := Prefix (P); + + -- For anything else, we don't have a match, so keep on + -- going, there are still some weird cases where we may + -- still have a replacement within the prefix. + + else + return OK; + end if; + end loop; + end if; + + -- Continue for any other node kind + + else + return OK; + end if; + end Replace_Node; + + begin + Replace_Type_Refs (N); + end Replace_Type_References_Generic; + + ------------------------- + -- Same_Representation -- + ------------------------- + + function Same_Representation (Typ1, Typ2 : Entity_Id) return Boolean is + T1 : constant Entity_Id := Underlying_Type (Typ1); + T2 : constant Entity_Id := Underlying_Type (Typ2); + + begin + -- A quick check, if base types are the same, then we definitely have + -- the same representation, because the subtype specific representation + -- attributes (Size and Alignment) do not affect representation from + -- the point of view of this test. + + if Base_Type (T1) = Base_Type (T2) then + return True; + + elsif Is_Private_Type (Base_Type (T2)) + and then Base_Type (T1) = Full_View (Base_Type (T2)) + then + return True; + end if; + + -- Tagged types never have differing representations + + if Is_Tagged_Type (T1) then + return True; + end if; + + -- Representations are definitely different if conventions differ + + if Convention (T1) /= Convention (T2) then + return False; + end if; + + -- Representations are different if component alignments differ + + if (Is_Record_Type (T1) or else Is_Array_Type (T1)) + and then + (Is_Record_Type (T2) or else Is_Array_Type (T2)) + and then Component_Alignment (T1) /= Component_Alignment (T2) + then + return False; + end if; + + -- For arrays, the only real issue is component size. If we know the + -- component size for both arrays, and it is the same, then that's + -- good enough to know we don't have a change of representation. + + if Is_Array_Type (T1) then + if Known_Component_Size (T1) + and then Known_Component_Size (T2) + and then Component_Size (T1) = Component_Size (T2) + then + return True; + end if; + end if; + + -- Types definitely have same representation if neither has non-standard + -- representation since default representations are always consistent. + -- If only one has non-standard representation, and the other does not, + -- then we consider that they do not have the same representation. They + -- might, but there is no way of telling early enough. + + if Has_Non_Standard_Rep (T1) then + if not Has_Non_Standard_Rep (T2) then + return False; + end if; + else + return not Has_Non_Standard_Rep (T2); + end if; + + -- Here the two types both have non-standard representation, and we need + -- to determine if they have the same non-standard representation. + + -- For arrays, we simply need to test if the component sizes are the + -- same. Pragma Pack is reflected in modified component sizes, so this + -- check also deals with pragma Pack. + + if Is_Array_Type (T1) then + return Component_Size (T1) = Component_Size (T2); + + -- Tagged types always have the same representation, because it is not + -- possible to specify different representations for common fields. + + elsif Is_Tagged_Type (T1) then + return True; + + -- Case of record types + + elsif Is_Record_Type (T1) then + + -- Packed status must conform + + if Is_Packed (T1) /= Is_Packed (T2) then + return False; + + -- Otherwise we must check components. Typ2 maybe a constrained + -- subtype with fewer components, so we compare the components + -- of the base types. + + else + Record_Case : declare + CD1, CD2 : Entity_Id; + + function Same_Rep return Boolean; + -- CD1 and CD2 are either components or discriminants. This + -- function tests whether the two have the same representation + + -------------- + -- Same_Rep -- + -------------- + + function Same_Rep return Boolean is + begin + if No (Component_Clause (CD1)) then + return No (Component_Clause (CD2)); + + else + return + Present (Component_Clause (CD2)) + and then + Component_Bit_Offset (CD1) = Component_Bit_Offset (CD2) + and then + Esize (CD1) = Esize (CD2); + end if; + end Same_Rep; + + -- Start of processing for Record_Case + + begin + if Has_Discriminants (T1) then + CD1 := First_Discriminant (T1); + CD2 := First_Discriminant (T2); + + -- The number of discriminants may be different if the + -- derived type has fewer (constrained by values). The + -- invisible discriminants retain the representation of + -- the original, so the discrepancy does not per se + -- indicate a different representation. + + while Present (CD1) + and then Present (CD2) + loop + if not Same_Rep then + return False; + else + Next_Discriminant (CD1); + Next_Discriminant (CD2); + end if; + end loop; + end if; + + CD1 := First_Component (Underlying_Type (Base_Type (T1))); + CD2 := First_Component (Underlying_Type (Base_Type (T2))); + + while Present (CD1) loop + if not Same_Rep then + return False; + else + Next_Component (CD1); + Next_Component (CD2); + end if; + end loop; + + return True; + end Record_Case; + end if; + + -- For enumeration types, we must check each literal to see if the + -- representation is the same. Note that we do not permit enumeration + -- representation clauses for Character and Wide_Character, so these + -- cases were already dealt with. + + elsif Is_Enumeration_Type (T1) then + Enumeration_Case : declare + L1, L2 : Entity_Id; + + begin + L1 := First_Literal (T1); + L2 := First_Literal (T2); + + while Present (L1) loop + if Enumeration_Rep (L1) /= Enumeration_Rep (L2) then + return False; + else + Next_Literal (L1); + Next_Literal (L2); + end if; + end loop; + + return True; + + end Enumeration_Case; + + -- Any other types have the same representation for these purposes + + else + return True; + end if; + end Same_Representation; + + ---------------- + -- Set_Biased -- + ---------------- + + procedure Set_Biased + (E : Entity_Id; + N : Node_Id; + Msg : String; + Biased : Boolean := True) + is + begin + if Biased then + Set_Has_Biased_Representation (E); + + if Warn_On_Biased_Representation then + Error_Msg_NE + ("?" & Msg & " forces biased representation for&", N, E); + end if; + end if; + end Set_Biased; + + -------------------- + -- Set_Enum_Esize -- + -------------------- + + procedure Set_Enum_Esize (T : Entity_Id) is + Lo : Uint; + Hi : Uint; + Sz : Nat; + + begin + Init_Alignment (T); + + -- Find the minimum standard size (8,16,32,64) that fits + + Lo := Enumeration_Rep (Entity (Type_Low_Bound (T))); + Hi := Enumeration_Rep (Entity (Type_High_Bound (T))); + + if Lo < 0 then + if Lo >= -Uint_2**07 and then Hi < Uint_2**07 then + Sz := Standard_Character_Size; -- May be > 8 on some targets + + elsif Lo >= -Uint_2**15 and then Hi < Uint_2**15 then + Sz := 16; + + elsif Lo >= -Uint_2**31 and then Hi < Uint_2**31 then + Sz := 32; + + else pragma Assert (Lo >= -Uint_2**63 and then Hi < Uint_2**63); + Sz := 64; + end if; + + else + if Hi < Uint_2**08 then + Sz := Standard_Character_Size; -- May be > 8 on some targets + + elsif Hi < Uint_2**16 then + Sz := 16; + + elsif Hi < Uint_2**32 then + Sz := 32; + + else pragma Assert (Hi < Uint_2**63); + Sz := 64; + end if; + end if; + + -- That minimum is the proper size unless we have a foreign convention + -- and the size required is 32 or less, in which case we bump the size + -- up to 32. This is required for C and C++ and seems reasonable for + -- all other foreign conventions. + + if Has_Foreign_Convention (T) + and then Esize (T) < Standard_Integer_Size + then + Init_Esize (T, Standard_Integer_Size); + else + Init_Esize (T, Sz); + end if; + end Set_Enum_Esize; + + ------------------------------ + -- Validate_Address_Clauses -- + ------------------------------ + + procedure Validate_Address_Clauses is + begin + for J in Address_Clause_Checks.First .. Address_Clause_Checks.Last loop + declare + ACCR : Address_Clause_Check_Record + renames Address_Clause_Checks.Table (J); + + Expr : Node_Id; + + X_Alignment : Uint; + Y_Alignment : Uint; + + X_Size : Uint; + Y_Size : Uint; + + begin + -- Skip processing of this entry if warning already posted + + if not Address_Warning_Posted (ACCR.N) then + + Expr := Original_Node (Expression (ACCR.N)); + + -- Get alignments + + X_Alignment := Alignment (ACCR.X); + Y_Alignment := Alignment (ACCR.Y); + + -- Similarly obtain sizes + + X_Size := Esize (ACCR.X); + Y_Size := Esize (ACCR.Y); + + -- Check for large object overlaying smaller one + + if Y_Size > Uint_0 + and then X_Size > Uint_0 + and then X_Size > Y_Size + then + Error_Msg_NE + ("?& overlays smaller object", ACCR.N, ACCR.X); + Error_Msg_N + ("\?program execution may be erroneous", ACCR.N); + Error_Msg_Uint_1 := X_Size; + Error_Msg_NE + ("\?size of & is ^", ACCR.N, ACCR.X); + Error_Msg_Uint_1 := Y_Size; + Error_Msg_NE + ("\?size of & is ^", ACCR.N, ACCR.Y); + + -- Check for inadequate alignment, both of the base object + -- and of the offset, if any. + + -- Note: we do not check the alignment if we gave a size + -- warning, since it would likely be redundant. + + elsif Y_Alignment /= Uint_0 + and then (Y_Alignment < X_Alignment + or else (ACCR.Off + and then + Nkind (Expr) = N_Attribute_Reference + and then + Attribute_Name (Expr) = Name_Address + and then + Has_Compatible_Alignment + (ACCR.X, Prefix (Expr)) + /= Known_Compatible)) + then + Error_Msg_NE + ("?specified address for& may be inconsistent " + & "with alignment", + ACCR.N, ACCR.X); + Error_Msg_N + ("\?program execution may be erroneous (RM 13.3(27))", + ACCR.N); + Error_Msg_Uint_1 := X_Alignment; + Error_Msg_NE + ("\?alignment of & is ^", + ACCR.N, ACCR.X); + Error_Msg_Uint_1 := Y_Alignment; + Error_Msg_NE + ("\?alignment of & is ^", + ACCR.N, ACCR.Y); + if Y_Alignment >= X_Alignment then + Error_Msg_N + ("\?but offset is not multiple of alignment", + ACCR.N); + end if; + end if; + end if; + end; + end loop; + end Validate_Address_Clauses; + + --------------------------- + -- Validate_Independence -- + --------------------------- + + procedure Validate_Independence is + SU : constant Uint := UI_From_Int (System_Storage_Unit); + N : Node_Id; + E : Entity_Id; + IC : Boolean; + Comp : Entity_Id; + Addr : Node_Id; + P : Node_Id; + + procedure Check_Array_Type (Atyp : Entity_Id); + -- Checks if the array type Atyp has independent components, and + -- if not, outputs an appropriate set of error messages. + + procedure No_Independence; + -- Output message that independence cannot be guaranteed + + function OK_Component (C : Entity_Id) return Boolean; + -- Checks one component to see if it is independently accessible, and + -- if so yields True, otherwise yields False if independent access + -- cannot be guaranteed. This is a conservative routine, it only + -- returns True if it knows for sure, it returns False if it knows + -- there is a problem, or it cannot be sure there is no problem. + + procedure Reason_Bad_Component (C : Entity_Id); + -- Outputs continuation message if a reason can be determined for + -- the component C being bad. + + ---------------------- + -- Check_Array_Type -- + ---------------------- + + procedure Check_Array_Type (Atyp : Entity_Id) is + Ctyp : constant Entity_Id := Component_Type (Atyp); + + begin + -- OK if no alignment clause, no pack, and no component size + + if not Has_Component_Size_Clause (Atyp) + and then not Has_Alignment_Clause (Atyp) + and then not Is_Packed (Atyp) + then + return; + end if; + + -- Check actual component size + + if not Known_Component_Size (Atyp) + or else not (Addressable (Component_Size (Atyp)) + and then Component_Size (Atyp) < 64) + or else Component_Size (Atyp) mod Esize (Ctyp) /= 0 + then + No_Independence; + + -- Bad component size, check reason + + if Has_Component_Size_Clause (Atyp) then + P := + Get_Attribute_Definition_Clause + (Atyp, Attribute_Component_Size); + + if Present (P) then + Error_Msg_Sloc := Sloc (P); + Error_Msg_N ("\because of Component_Size clause#", N); + return; + end if; + end if; + + if Is_Packed (Atyp) then + P := Get_Rep_Pragma (Atyp, Name_Pack); + + if Present (P) then + Error_Msg_Sloc := Sloc (P); + Error_Msg_N ("\because of pragma Pack#", N); + return; + end if; + end if; + + -- No reason found, just return + + return; + end if; + + -- Array type is OK independence-wise + + return; + end Check_Array_Type; + + --------------------- + -- No_Independence -- + --------------------- + + procedure No_Independence is + begin + if Pragma_Name (N) = Name_Independent then + Error_Msg_NE + ("independence cannot be guaranteed for&", N, E); + else + Error_Msg_NE + ("independent components cannot be guaranteed for&", N, E); + end if; + end No_Independence; + + ------------------ + -- OK_Component -- + ------------------ + + function OK_Component (C : Entity_Id) return Boolean is + Rec : constant Entity_Id := Scope (C); + Ctyp : constant Entity_Id := Etype (C); + + begin + -- OK if no component clause, no Pack, and no alignment clause + + if No (Component_Clause (C)) + and then not Is_Packed (Rec) + and then not Has_Alignment_Clause (Rec) + then + return True; + end if; + + -- Here we look at the actual component layout. A component is + -- addressable if its size is a multiple of the Esize of the + -- component type, and its starting position in the record has + -- appropriate alignment, and the record itself has appropriate + -- alignment to guarantee the component alignment. + + -- Make sure sizes are static, always assume the worst for any + -- cases where we cannot check static values. + + if not (Known_Static_Esize (C) + and then Known_Static_Esize (Ctyp)) + then + return False; + end if; + + -- Size of component must be addressable or greater than 64 bits + -- and a multiple of bytes. + + if not Addressable (Esize (C)) + and then Esize (C) < Uint_64 + then + return False; + end if; + + -- Check size is proper multiple + + if Esize (C) mod Esize (Ctyp) /= 0 then + return False; + end if; + + -- Check alignment of component is OK + + if not Known_Component_Bit_Offset (C) + or else Component_Bit_Offset (C) < Uint_0 + or else Component_Bit_Offset (C) mod Esize (Ctyp) /= 0 + then + return False; + end if; + + -- Check alignment of record type is OK + + if not Known_Alignment (Rec) + or else (Alignment (Rec) * SU) mod Esize (Ctyp) /= 0 + then + return False; + end if; + + -- All tests passed, component is addressable + + return True; + end OK_Component; + + -------------------------- + -- Reason_Bad_Component -- + -------------------------- + + procedure Reason_Bad_Component (C : Entity_Id) is + Rec : constant Entity_Id := Scope (C); + Ctyp : constant Entity_Id := Etype (C); + + begin + -- If component clause present assume that's the problem + + if Present (Component_Clause (C)) then + Error_Msg_Sloc := Sloc (Component_Clause (C)); + Error_Msg_N ("\because of Component_Clause#", N); + return; + end if; + + -- If pragma Pack clause present, assume that's the problem + + if Is_Packed (Rec) then + P := Get_Rep_Pragma (Rec, Name_Pack); + + if Present (P) then + Error_Msg_Sloc := Sloc (P); + Error_Msg_N ("\because of pragma Pack#", N); + return; + end if; + end if; + + -- See if record has bad alignment clause + + if Has_Alignment_Clause (Rec) + and then Known_Alignment (Rec) + and then (Alignment (Rec) * SU) mod Esize (Ctyp) /= 0 + then + P := Get_Attribute_Definition_Clause (Rec, Attribute_Alignment); + + if Present (P) then + Error_Msg_Sloc := Sloc (P); + Error_Msg_N ("\because of Alignment clause#", N); + end if; + end if; + + -- Couldn't find a reason, so return without a message + + return; + end Reason_Bad_Component; + + -- Start of processing for Validate_Independence + + begin + for J in Independence_Checks.First .. Independence_Checks.Last loop + N := Independence_Checks.Table (J).N; + E := Independence_Checks.Table (J).E; + IC := Pragma_Name (N) = Name_Independent_Components; + + -- Deal with component case + + if Ekind (E) = E_Discriminant or else Ekind (E) = E_Component then + if not OK_Component (E) then + No_Independence; + Reason_Bad_Component (E); + goto Continue; + end if; + end if; + + -- Deal with record with Independent_Components + + if IC and then Is_Record_Type (E) then + Comp := First_Component_Or_Discriminant (E); + while Present (Comp) loop + if not OK_Component (Comp) then + No_Independence; + Reason_Bad_Component (Comp); + goto Continue; + end if; + + Next_Component_Or_Discriminant (Comp); + end loop; + end if; + + -- Deal with address clause case + + if Is_Object (E) then + Addr := Address_Clause (E); + + if Present (Addr) then + No_Independence; + Error_Msg_Sloc := Sloc (Addr); + Error_Msg_N ("\because of Address clause#", N); + goto Continue; + end if; + end if; + + -- Deal with independent components for array type + + if IC and then Is_Array_Type (E) then + Check_Array_Type (E); + end if; + + -- Deal with independent components for array object + + if IC and then Is_Object (E) and then Is_Array_Type (Etype (E)) then + Check_Array_Type (Etype (E)); + end if; + + <> null; + end loop; + end Validate_Independence; + + ----------------------------------- + -- Validate_Unchecked_Conversion -- + ----------------------------------- + + procedure Validate_Unchecked_Conversion + (N : Node_Id; + Act_Unit : Entity_Id) + is + Source : Entity_Id; + Target : Entity_Id; + Vnode : Node_Id; + + begin + -- Obtain source and target types. Note that we call Ancestor_Subtype + -- here because the processing for generic instantiation always makes + -- subtypes, and we want the original frozen actual types. + + -- If we are dealing with private types, then do the check on their + -- fully declared counterparts if the full declarations have been + -- encountered (they don't have to be visible, but they must exist!) + + Source := Ancestor_Subtype (Etype (First_Formal (Act_Unit))); + + if Is_Private_Type (Source) + and then Present (Underlying_Type (Source)) + then + Source := Underlying_Type (Source); + end if; + + Target := Ancestor_Subtype (Etype (Act_Unit)); + + -- If either type is generic, the instantiation happens within a generic + -- unit, and there is nothing to check. The proper check + -- will happen when the enclosing generic is instantiated. + + if Is_Generic_Type (Source) or else Is_Generic_Type (Target) then + return; + end if; + + if Is_Private_Type (Target) + and then Present (Underlying_Type (Target)) + then + Target := Underlying_Type (Target); + end if; + + -- Source may be unconstrained array, but not target + + if Is_Array_Type (Target) + and then not Is_Constrained (Target) + then + Error_Msg_N + ("unchecked conversion to unconstrained array not allowed", N); + return; + end if; + + -- Warn if conversion between two different convention pointers + + if Is_Access_Type (Target) + and then Is_Access_Type (Source) + and then Convention (Target) /= Convention (Source) + and then Warn_On_Unchecked_Conversion + then + -- Give warnings for subprogram pointers only on most targets. The + -- exception is VMS, where data pointers can have different lengths + -- depending on the pointer convention. + + if Is_Access_Subprogram_Type (Target) + or else Is_Access_Subprogram_Type (Source) + or else OpenVMS_On_Target + then + Error_Msg_N + ("?conversion between pointers with different conventions!", N); + end if; + end if; + + -- Warn if one of the operands is Ada.Calendar.Time. Do not emit a + -- warning when compiling GNAT-related sources. + + if Warn_On_Unchecked_Conversion + and then not In_Predefined_Unit (N) + and then RTU_Loaded (Ada_Calendar) + and then + (Chars (Source) = Name_Time + or else + Chars (Target) = Name_Time) + then + -- If Ada.Calendar is loaded and the name of one of the operands is + -- Time, there is a good chance that this is Ada.Calendar.Time. + + declare + Calendar_Time : constant Entity_Id := + Full_View (RTE (RO_CA_Time)); + begin + pragma Assert (Present (Calendar_Time)); + + if Source = Calendar_Time + or else Target = Calendar_Time + then + Error_Msg_N + ("?representation of 'Time values may change between " & + "'G'N'A'T versions", N); + end if; + end; + end if; + + -- Make entry in unchecked conversion table for later processing by + -- Validate_Unchecked_Conversions, which will check sizes and alignments + -- (using values set by the back-end where possible). This is only done + -- if the appropriate warning is active. + + if Warn_On_Unchecked_Conversion then + Unchecked_Conversions.Append + (New_Val => UC_Entry' + (Eloc => Sloc (N), + Source => Source, + Target => Target)); + + -- If both sizes are known statically now, then back end annotation + -- is not required to do a proper check but if either size is not + -- known statically, then we need the annotation. + + if Known_Static_RM_Size (Source) + and then Known_Static_RM_Size (Target) + then + null; + else + Back_Annotate_Rep_Info := True; + end if; + end if; + + -- If unchecked conversion to access type, and access type is declared + -- in the same unit as the unchecked conversion, then set the + -- No_Strict_Aliasing flag (no strict aliasing is implicit in this + -- situation). + + if Is_Access_Type (Target) and then + In_Same_Source_Unit (Target, N) + then + Set_No_Strict_Aliasing (Implementation_Base_Type (Target)); + end if; + + -- Generate N_Validate_Unchecked_Conversion node for back end in + -- case the back end needs to perform special validation checks. + + -- Shouldn't this be in Exp_Ch13, since the check only gets done + -- if we have full expansion and the back end is called ??? + + Vnode := + Make_Validate_Unchecked_Conversion (Sloc (N)); + Set_Source_Type (Vnode, Source); + Set_Target_Type (Vnode, Target); + + -- If the unchecked conversion node is in a list, just insert before it. + -- If not we have some strange case, not worth bothering about. + + if Is_List_Member (N) then + Insert_After (N, Vnode); + end if; + end Validate_Unchecked_Conversion; + + ------------------------------------ + -- Validate_Unchecked_Conversions -- + ------------------------------------ + + procedure Validate_Unchecked_Conversions is + begin + for N in Unchecked_Conversions.First .. Unchecked_Conversions.Last loop + declare + T : UC_Entry renames Unchecked_Conversions.Table (N); + + Eloc : constant Source_Ptr := T.Eloc; + Source : constant Entity_Id := T.Source; + Target : constant Entity_Id := T.Target; + + Source_Siz : Uint; + Target_Siz : Uint; + + begin + -- This validation check, which warns if we have unequal sizes for + -- unchecked conversion, and thus potentially implementation + -- dependent semantics, is one of the few occasions on which we + -- use the official RM size instead of Esize. See description in + -- Einfo "Handling of Type'Size Values" for details. + + if Serious_Errors_Detected = 0 + and then Known_Static_RM_Size (Source) + and then Known_Static_RM_Size (Target) + + -- Don't do the check if warnings off for either type, note the + -- deliberate use of OR here instead of OR ELSE to get the flag + -- Warnings_Off_Used set for both types if appropriate. + + and then not (Has_Warnings_Off (Source) + or + Has_Warnings_Off (Target)) + then + Source_Siz := RM_Size (Source); + Target_Siz := RM_Size (Target); + + if Source_Siz /= Target_Siz then + Error_Msg + ("?types for unchecked conversion have different sizes!", + Eloc); + + if All_Errors_Mode then + Error_Msg_Name_1 := Chars (Source); + Error_Msg_Uint_1 := Source_Siz; + Error_Msg_Name_2 := Chars (Target); + Error_Msg_Uint_2 := Target_Siz; + Error_Msg ("\size of % is ^, size of % is ^?", Eloc); + + Error_Msg_Uint_1 := UI_Abs (Source_Siz - Target_Siz); + + if Is_Discrete_Type (Source) + and then Is_Discrete_Type (Target) + then + if Source_Siz > Target_Siz then + Error_Msg + ("\?^ high order bits of source will be ignored!", + Eloc); + + elsif Is_Unsigned_Type (Source) then + Error_Msg + ("\?source will be extended with ^ high order " & + "zero bits?!", Eloc); + + else + Error_Msg + ("\?source will be extended with ^ high order " & + "sign bits!", + Eloc); + end if; + + elsif Source_Siz < Target_Siz then + if Is_Discrete_Type (Target) then + if Bytes_Big_Endian then + Error_Msg + ("\?target value will include ^ undefined " & + "low order bits!", + Eloc); + else + Error_Msg + ("\?target value will include ^ undefined " & + "high order bits!", + Eloc); + end if; + + else + Error_Msg + ("\?^ trailing bits of target value will be " & + "undefined!", Eloc); + end if; + + else pragma Assert (Source_Siz > Target_Siz); + Error_Msg + ("\?^ trailing bits of source will be ignored!", + Eloc); + end if; + end if; + end if; + end if; + + -- If both types are access types, we need to check the alignment. + -- If the alignment of both is specified, we can do it here. + + if Serious_Errors_Detected = 0 + and then Ekind (Source) in Access_Kind + and then Ekind (Target) in Access_Kind + and then Target_Strict_Alignment + and then Present (Designated_Type (Source)) + and then Present (Designated_Type (Target)) + then + declare + D_Source : constant Entity_Id := Designated_Type (Source); + D_Target : constant Entity_Id := Designated_Type (Target); + + begin + if Known_Alignment (D_Source) + and then Known_Alignment (D_Target) + then + declare + Source_Align : constant Uint := Alignment (D_Source); + Target_Align : constant Uint := Alignment (D_Target); + + begin + if Source_Align < Target_Align + and then not Is_Tagged_Type (D_Source) + + -- Suppress warning if warnings suppressed on either + -- type or either designated type. Note the use of + -- OR here instead of OR ELSE. That is intentional, + -- we would like to set flag Warnings_Off_Used in + -- all types for which warnings are suppressed. + + and then not (Has_Warnings_Off (D_Source) + or + Has_Warnings_Off (D_Target) + or + Has_Warnings_Off (Source) + or + Has_Warnings_Off (Target)) + then + Error_Msg_Uint_1 := Target_Align; + Error_Msg_Uint_2 := Source_Align; + Error_Msg_Node_1 := D_Target; + Error_Msg_Node_2 := D_Source; + Error_Msg + ("?alignment of & (^) is stricter than " & + "alignment of & (^)!", Eloc); + Error_Msg + ("\?resulting access value may have invalid " & + "alignment!", Eloc); + end if; + end; + end if; + end; + end if; + end; + end loop; + end Validate_Unchecked_Conversions; + +end Sem_Ch13; -- cgit v1.2.3