obtained gcc-4.6.4.tar.bz2 from upstream website;upstream

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.

1 files changed, 1225 insertions, 0 deletions

diff --git a/gcc/cp/except.c b/gcc/cp/except.c
new file mode 100644
index 000000000..874f11150
--- /dev/null
+++ b/gcc/cp/except.c
@@ -0,0 +1,1225 @@
+/* Handle exceptional things in C++.
+   Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
+   2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010
+   Free Software Foundation, Inc.
+   Contributed by Michael Tiemann <tiemann@cygnus.com>
+   Rewritten by Mike Stump <mrs@cygnus.com>, based upon an
+   initial re-implementation courtesy Tad Hunt.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT 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
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "tree.h"
+#include "cp-tree.h"
+#include "flags.h"
+#include "output.h"
+#include "tree-inline.h"
+#include "tree-iterator.h"
+#include "target.h"
+#include "gimple.h"
+
+static void push_eh_cleanup (tree);
+static tree prepare_eh_type (tree);
+static tree do_begin_catch (void);
+static int dtor_nothrow (tree);
+static tree do_end_catch (tree);
+static bool decl_is_java_type (tree decl, int err);
+static void initialize_handler_parm (tree, tree);
+static tree do_allocate_exception (tree);
+static tree wrap_cleanups_r (tree *, int *, void *);
+static int complete_ptr_ref_or_void_ptr_p (tree, tree);
+static bool is_admissible_throw_operand (tree);
+static int can_convert_eh (tree, tree);
+
+/* Sets up all the global eh stuff that needs to be initialized at the
+   start of compilation.  */
+
+void
+init_exception_processing (void)
+{
+  tree tmp;
+
+  /* void std::terminate (); */
+  push_namespace (std_identifier);
+  tmp = build_function_type_list (void_type_node, NULL_TREE);
+  terminate_node = build_cp_library_fn_ptr ("terminate", tmp);
+  TREE_THIS_VOLATILE (terminate_node) = 1;
+  TREE_NOTHROW (terminate_node) = 1;
+  pop_namespace ();
+
+  /* void __cxa_call_unexpected(void *); */
+  tmp = build_function_type_list (void_type_node, ptr_type_node, NULL_TREE);
+  call_unexpected_node
+    = push_throw_library_fn (get_identifier ("__cxa_call_unexpected"), tmp);
+}
+
+/* Returns an expression to be executed if an unhandled exception is
+   propagated out of a cleanup region.  */
+
+tree
+cp_protect_cleanup_actions (void)
+{
+  /* [except.terminate]
+
+     When the destruction of an object during stack unwinding exits
+     using an exception ... void terminate(); is called.  */
+  return terminate_node;
+}
+
+static tree
+prepare_eh_type (tree type)
+{
+  if (type == NULL_TREE)
+    return type;
+  if (type == error_mark_node)
+    return error_mark_node;
+
+  /* peel back references, so they match.  */
+  type = non_reference (type);
+
+  /* Peel off cv qualifiers.  */
+  type = TYPE_MAIN_VARIANT (type);
+
+  /* Functions and arrays decay to pointers.  */
+  type = type_decays_to (type);
+
+  return type;
+}
+
+/* Return the type info for TYPE as used by EH machinery.  */
+tree
+eh_type_info (tree type)
+{
+  tree exp;
+
+  if (type == NULL_TREE || type == error_mark_node)
+    return type;
+
+  if (decl_is_java_type (type, 0))
+    exp = build_java_class_ref (TREE_TYPE (type));
+  else
+    exp = get_tinfo_decl (type);
+
+  return exp;
+}
+
+/* Build the address of a typeinfo decl for use in the runtime
+   matching field of the exception model.  */
+
+tree
+build_eh_type_type (tree type)
+{
+  tree exp = eh_type_info (type);
+
+  if (!exp)
+    return NULL;
+
+  mark_used (exp);
+
+  return convert (ptr_type_node, build_address (exp));
+}
+
+tree
+build_exc_ptr (void)
+{
+  return build_call_n (built_in_decls [BUILT_IN_EH_POINTER],
+		       1, integer_zero_node);
+}
+
+/* Declare a function NAME, returning RETURN_TYPE, taking a single
+   parameter PARM_TYPE, with an empty exception specification.
+
+   Note that the C++ ABI document does not have a throw-specifier on
+   the routines declared below via this function.  The declarations
+   are consistent with the actual implementations in libsupc++.  */
+
+static tree
+declare_nothrow_library_fn (tree name, tree return_type, tree parm_type)
+{
+  return push_library_fn (name, build_function_type_list (return_type,
+							  parm_type,
+							  NULL_TREE),
+			  empty_except_spec);
+}
+
+/* Build up a call to __cxa_get_exception_ptr so that we can build a
+   copy constructor for the thrown object.  */
+
+static tree
+do_get_exception_ptr (void)
+{
+  tree fn;
+
+  fn = get_identifier ("__cxa_get_exception_ptr");
+  if (!get_global_value_if_present (fn, &fn))
+    {
+      /* Declare void* __cxa_get_exception_ptr (void *) throw().  */
+      fn = declare_nothrow_library_fn (fn, ptr_type_node, ptr_type_node);
+    }
+
+  return cp_build_function_call_nary (fn, tf_warning_or_error,
+				      build_exc_ptr (), NULL_TREE);
+}
+
+/* Build up a call to __cxa_begin_catch, to tell the runtime that the
+   exception has been handled.  */
+
+static tree
+do_begin_catch (void)
+{
+  tree fn;
+
+  fn = get_identifier ("__cxa_begin_catch");
+  if (!get_global_value_if_present (fn, &fn))
+    {
+      /* Declare void* __cxa_begin_catch (void *) throw().  */
+      fn = declare_nothrow_library_fn (fn, ptr_type_node, ptr_type_node);
+    }
+
+  return cp_build_function_call_nary (fn, tf_warning_or_error,
+				      build_exc_ptr (), NULL_TREE);
+}
+
+/* Returns nonzero if cleaning up an exception of type TYPE (which can be
+   NULL_TREE for a ... handler) will not throw an exception.  */
+
+static int
+dtor_nothrow (tree type)
+{
+  if (type == NULL_TREE || type == error_mark_node)
+    return 0;
+
+  if (TYPE_HAS_TRIVIAL_DESTRUCTOR (type))
+    return 1;
+
+  if (CLASSTYPE_LAZY_DESTRUCTOR (type))
+    lazily_declare_fn (sfk_destructor, type);
+
+  return TREE_NOTHROW (CLASSTYPE_DESTRUCTORS (type));
+}
+
+/* Build up a call to __cxa_end_catch, to destroy the exception object
+   for the current catch block if no others are currently using it.  */
+
+static tree
+do_end_catch (tree type)
+{
+  tree fn, cleanup;
+
+  fn = get_identifier ("__cxa_end_catch");
+  if (!get_global_value_if_present (fn, &fn))
+    {
+      /* Declare void __cxa_end_catch ().  */
+      fn = push_void_library_fn (fn, void_list_node);
+      /* This can throw if the destructor for the exception throws.  */
+      TREE_NOTHROW (fn) = 0;
+    }
+
+  cleanup = cp_build_function_call_vec (fn, NULL, tf_warning_or_error);
+  TREE_NOTHROW (cleanup) = dtor_nothrow (type);
+
+  return cleanup;
+}
+
+/* This routine creates the cleanup for the current exception.  */
+
+static void
+push_eh_cleanup (tree type)
+{
+  finish_decl_cleanup (NULL_TREE, do_end_catch (type));
+}
+
+/* Return nonzero value if DECL is a Java type suitable for catch or
+   throw.  */
+
+static bool
+decl_is_java_type (tree decl, int err)
+{
+  bool r = (TREE_CODE (decl) == POINTER_TYPE
+	    && TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
+	    && TYPE_FOR_JAVA (TREE_TYPE (decl)));
+
+  if (err)
+    {
+      if (TREE_CODE (decl) == REFERENCE_TYPE
+	  && TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
+	  && TYPE_FOR_JAVA (TREE_TYPE (decl)))
+	{
+	  /* Can't throw a reference.  */
+	  error ("type %qT is disallowed in Java %<throw%> or %<catch%>",
+		 decl);
+	}
+
+      if (r)
+	{
+	  tree jthrow_node
+	    = IDENTIFIER_GLOBAL_VALUE (get_identifier ("jthrowable"));
+
+	  if (jthrow_node == NULL_TREE)
+	    fatal_error
+	      ("call to Java %<catch%> or %<throw%> with %<jthrowable%> undefined");
+
+	  jthrow_node = TREE_TYPE (TREE_TYPE (jthrow_node));
+
+	  if (! DERIVED_FROM_P (jthrow_node, TREE_TYPE (decl)))
+	    {
+	      /* Thrown object must be a Throwable.  */
+	      error ("type %qT is not derived from %<java::lang::Throwable%>",
+		     TREE_TYPE (decl));
+	    }
+	}
+    }
+
+  return r;
+}
+
+/* Select the personality routine to be used for exception handling,
+   or issue an error if we need two different ones in the same
+   translation unit.
+   ??? At present DECL_FUNCTION_PERSONALITY is set via
+   LANG_HOOKS_EH_PERSONALITY.  Should it be done here instead?  */
+void
+choose_personality_routine (enum languages lang)
+{
+  static enum {
+    chose_none,
+    chose_cpp,
+    chose_java,
+    gave_error
+  } state;
+
+  switch (state)
+    {
+    case gave_error:
+      return;
+
+    case chose_cpp:
+      if (lang != lang_cplusplus)
+	goto give_error;
+      return;
+
+    case chose_java:
+      if (lang != lang_java)
+	goto give_error;
+      return;
+
+    case chose_none:
+      ; /* Proceed to language selection.  */
+    }
+
+  switch (lang)
+    {
+    case lang_cplusplus:
+      state = chose_cpp;
+      break;
+
+    case lang_java:
+      state = chose_java;
+      terminate_node = built_in_decls [BUILT_IN_ABORT];
+      pragma_java_exceptions = true;
+      break;
+
+    default:
+      gcc_unreachable ();
+    }
+  return;
+
+ give_error:
+  error ("mixing C++ and Java catches in a single translation unit");
+  state = gave_error;
+}
+
+/* Initialize the catch parameter DECL.  */
+
+static void
+initialize_handler_parm (tree decl, tree exp)
+{
+  tree init;
+  tree init_type;
+
+  /* Make sure we mark the catch param as used, otherwise we'll get a
+     warning about an unused ((anonymous)).  */
+  TREE_USED (decl) = 1;
+  DECL_READ_P (decl) = 1;
+
+  /* Figure out the type that the initializer is.  Pointers are returned
+     adjusted by value from __cxa_begin_catch.  Others are returned by
+     reference.  */
+  init_type = TREE_TYPE (decl);
+  if (!POINTER_TYPE_P (init_type))
+    init_type = build_reference_type (init_type);
+
+  choose_personality_routine (decl_is_java_type (init_type, 0)
+			      ? lang_java : lang_cplusplus);
+
+  /* Since pointers are passed by value, initialize a reference to
+     pointer catch parm with the address of the temporary.  */
+  if (TREE_CODE (init_type) == REFERENCE_TYPE
+      && TYPE_PTR_P (TREE_TYPE (init_type)))
+    exp = cp_build_addr_expr (exp, tf_warning_or_error);
+
+  exp = ocp_convert (init_type, exp, CONV_IMPLICIT|CONV_FORCE_TEMP, 0);
+
+  init = convert_from_reference (exp);
+
+  /* If the constructor for the catch parm exits via an exception, we
+     must call terminate.  See eh23.C.  */
+  if (TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl)))
+    {
+      /* Generate the copy constructor call directly so we can wrap it.
+	 See also expand_default_init.  */
+      init = ocp_convert (TREE_TYPE (decl), init,
+			  CONV_IMPLICIT|CONV_FORCE_TEMP, 0);
+      /* Force cleanups now to avoid nesting problems with the
+	 MUST_NOT_THROW_EXPR.  */
+      init = fold_build_cleanup_point_expr (TREE_TYPE (init), init);
+      init = build1 (MUST_NOT_THROW_EXPR, TREE_TYPE (init), init);
+    }
+
+  decl = pushdecl (decl);
+
+  start_decl_1 (decl, true);
+  cp_finish_decl (decl, init, /*init_const_expr_p=*/false, NULL_TREE,
+		  LOOKUP_ONLYCONVERTING|DIRECT_BIND);
+}
+
+
+/* Routine to see if exception handling is turned on.
+   DO_WARN is nonzero if we want to inform the user that exception
+   handling is turned off.
+
+   This is used to ensure that -fexceptions has been specified if the
+   compiler tries to use any exception-specific functions.  */
+
+static inline int
+doing_eh (void)
+{
+  if (! flag_exceptions)
+    {
+      static int warned = 0;
+      if (! warned)
+	{
+	  error ("exception handling disabled, use -fexceptions to enable");
+	  warned = 1;
+	}
+      return 0;
+    }
+  return 1;
+}
+
+/* Call this to start a catch block.  DECL is the catch parameter.  */
+
+tree
+expand_start_catch_block (tree decl)
+{
+  tree exp;
+  tree type, init;
+
+  if (! doing_eh ())
+    return NULL_TREE;
+
+  /* Make sure this declaration is reasonable.  */
+  if (decl && !complete_ptr_ref_or_void_ptr_p (TREE_TYPE (decl), NULL_TREE))
+    decl = error_mark_node;
+
+  if (decl)
+    type = prepare_eh_type (TREE_TYPE (decl));
+  else
+    type = NULL_TREE;
+
+  if (decl && decl_is_java_type (type, 1))
+    {
+      /* Java only passes object via pointer and doesn't require
+	 adjusting.  The java object is immediately before the
+	 generic exception header.  */
+      exp = build_exc_ptr ();
+      exp = build1 (NOP_EXPR, build_pointer_type (type), exp);
+      exp = build2 (POINTER_PLUS_EXPR, TREE_TYPE (exp), exp,
+		    fold_build1_loc (input_location,
+				 NEGATE_EXPR, sizetype,
+			 	 TYPE_SIZE_UNIT (TREE_TYPE (exp))));
+      exp = cp_build_indirect_ref (exp, RO_NULL, tf_warning_or_error);
+      initialize_handler_parm (decl, exp);
+      return type;
+    }
+
+  /* Call __cxa_end_catch at the end of processing the exception.  */
+  push_eh_cleanup (type);
+
+  init = do_begin_catch ();
+
+  /* If there's no decl at all, then all we need to do is make sure
+     to tell the runtime that we've begun handling the exception.  */
+  if (decl == NULL || decl == error_mark_node || init == error_mark_node)
+    finish_expr_stmt (init);
+
+  /* If the C++ object needs constructing, we need to do that before
+     calling __cxa_begin_catch, so that std::uncaught_exception gets
+     the right value during the copy constructor.  */
+  else if (flag_use_cxa_get_exception_ptr
+	   && TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl)))
+    {
+      exp = do_get_exception_ptr ();
+      initialize_handler_parm (decl, exp);
+      finish_expr_stmt (init);
+    }
+
+  /* Otherwise the type uses a bitwise copy, and we don't have to worry
+     about the value of std::uncaught_exception and therefore can do the
+     copy with the return value of __cxa_end_catch instead.  */
+  else
+    {
+      tree init_type = type;
+
+      /* Pointers are passed by values, everything else by reference.  */
+      if (!TYPE_PTR_P (type))
+	init_type = build_pointer_type (type);
+      if (init_type != TREE_TYPE (init))
+	init = build1 (NOP_EXPR, init_type, init);
+      exp = create_temporary_var (init_type);
+      DECL_REGISTER (exp) = 1;
+      cp_finish_decl (exp, init, /*init_const_expr=*/false,
+		      NULL_TREE, LOOKUP_ONLYCONVERTING);
+      initialize_handler_parm (decl, exp);
+    }
+
+  return type;
+}
+
+
+/* Call this to end a catch block.  Its responsible for emitting the
+   code to handle jumping back to the correct place, and for emitting
+   the label to jump to if this catch block didn't match.  */
+
+void
+expand_end_catch_block (void)
+{
+  if (! doing_eh ())
+    return;
+
+  /* The exception being handled is rethrown if control reaches the end of
+     a handler of the function-try-block of a constructor or destructor.  */
+  if (in_function_try_handler
+      && (DECL_CONSTRUCTOR_P (current_function_decl)
+	  || DECL_DESTRUCTOR_P (current_function_decl)))
+    finish_expr_stmt (build_throw (NULL_TREE));
+}
+
+tree
+begin_eh_spec_block (void)
+{
+  tree r;
+  /* A noexcept specification (or throw() with -fnothrow-opt) is a
+     MUST_NOT_THROW_EXPR.  */
+  if (TYPE_NOEXCEPT_P (TREE_TYPE (current_function_decl)))
+    {
+      r = build_stmt (input_location, MUST_NOT_THROW_EXPR, NULL_TREE);
+      TREE_SIDE_EFFECTS (r) = 1;
+    }
+  else
+    r = build_stmt (input_location, EH_SPEC_BLOCK, NULL_TREE, NULL_TREE);
+  add_stmt (r);
+  TREE_OPERAND (r, 0) = push_stmt_list ();
+  return r;
+}
+
+void
+finish_eh_spec_block (tree raw_raises, tree eh_spec_block)
+{
+  tree raises;
+
+  TREE_OPERAND (eh_spec_block, 0)
+    = pop_stmt_list (TREE_OPERAND (eh_spec_block, 0));
+
+  if (TREE_CODE (eh_spec_block) == MUST_NOT_THROW_EXPR)
+    return;
+
+  /* Strip cv quals, etc, from the specification types.  */
+  for (raises = NULL_TREE;
+       raw_raises && TREE_VALUE (raw_raises);
+       raw_raises = TREE_CHAIN (raw_raises))
+    {
+      tree type = prepare_eh_type (TREE_VALUE (raw_raises));
+      tree tinfo = eh_type_info (type);
+
+      mark_used (tinfo);
+      raises = tree_cons (NULL_TREE, type, raises);
+    }
+
+  EH_SPEC_RAISES (eh_spec_block) = raises;
+}
+
+/* Return a pointer to a buffer for an exception object of type TYPE.  */
+
+static tree
+do_allocate_exception (tree type)
+{
+  tree fn;
+
+  fn = get_identifier ("__cxa_allocate_exception");
+  if (!get_global_value_if_present (fn, &fn))
+    {
+      /* Declare void *__cxa_allocate_exception(size_t) throw().  */
+      fn = declare_nothrow_library_fn (fn, ptr_type_node, size_type_node);
+    }
+
+  return cp_build_function_call_nary (fn, tf_warning_or_error,
+				      size_in_bytes (type), NULL_TREE);
+}
+
+/* Call __cxa_free_exception from a cleanup.  This is never invoked
+   directly, but see the comment for stabilize_throw_expr.  */
+
+static tree
+do_free_exception (tree ptr)
+{
+  tree fn;
+
+  fn = get_identifier ("__cxa_free_exception");
+  if (!get_global_value_if_present (fn, &fn))
+    {
+      /* Declare void __cxa_free_exception (void *) throw().  */
+      fn = declare_nothrow_library_fn (fn, void_type_node, ptr_type_node);
+    }
+
+  return cp_build_function_call_nary (fn, tf_warning_or_error, ptr, NULL_TREE);
+}
+
+/* Wrap all cleanups for TARGET_EXPRs in MUST_NOT_THROW_EXPR.
+   Called from build_throw via walk_tree_without_duplicates.  */
+
+static tree
+wrap_cleanups_r (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
+		 void *data ATTRIBUTE_UNUSED)
+{
+  tree exp = *tp;
+  tree cleanup;
+
+  /* Don't walk into types.  */
+  if (TYPE_P (exp))
+    {
+      *walk_subtrees = 0;
+      return NULL_TREE;
+    }
+  if (TREE_CODE (exp) != TARGET_EXPR)
+    return NULL_TREE;
+
+  cleanup = TARGET_EXPR_CLEANUP (exp);
+  if (cleanup)
+    {
+      cleanup = build1 (MUST_NOT_THROW_EXPR, void_type_node, cleanup);
+      TARGET_EXPR_CLEANUP (exp) = cleanup;
+    }
+
+  /* Keep iterating.  */
+  return NULL_TREE;
+}
+
+/* Build a throw expression.  */
+
+tree
+build_throw (tree exp)
+{
+  tree fn;
+
+  if (exp == error_mark_node)
+    return exp;
+
+  if (processing_template_decl)
+    {
+      if (cfun)
+	current_function_returns_abnormally = 1;
+      exp = build_min (THROW_EXPR, void_type_node, exp);
+      SET_EXPR_LOCATION (exp, input_location);
+      return exp;
+    }
+
+  if (exp == null_node)
+    warning (0, "throwing NULL, which has integral, not pointer type");
+
+  if (exp != NULL_TREE)
+    {
+      if (!is_admissible_throw_operand (exp))
+	return error_mark_node;
+    }
+
+  if (! doing_eh ())
+    return error_mark_node;
+
+  if (exp && decl_is_java_type (TREE_TYPE (exp), 1))
+    {
+      tree fn = get_identifier ("_Jv_Throw");
+      if (!get_global_value_if_present (fn, &fn))
+	{
+	  /* Declare void _Jv_Throw (void *).  */
+	  tree tmp;
+	  tmp = build_function_type_list (ptr_type_node,
+					  ptr_type_node, NULL_TREE);
+	  fn = push_throw_library_fn (fn, tmp);
+	}
+      else if (really_overloaded_fn (fn))
+	{
+	  error ("%qD should never be overloaded", fn);
+	  return error_mark_node;
+	}
+      fn = OVL_CURRENT (fn);
+      exp = cp_build_function_call_nary (fn, tf_warning_or_error,
+					 exp, NULL_TREE);
+    }
+  else if (exp)
+    {
+      tree throw_type;
+      tree temp_type;
+      tree cleanup;
+      tree object, ptr;
+      tree tmp;
+      tree allocate_expr;
+
+      /* The CLEANUP_TYPE is the internal type of a destructor.  */
+      if (!cleanup_type)
+	{
+	  tmp = build_function_type_list (void_type_node,
+					  ptr_type_node, NULL_TREE);
+	  cleanup_type = build_pointer_type (tmp);
+	}
+
+      fn = get_identifier ("__cxa_throw");
+      if (!get_global_value_if_present (fn, &fn))
+	{
+	  /* Declare void __cxa_throw (void*, void*, void (*)(void*)).  */
+	  /* ??? Second argument is supposed to be "std::type_info*".  */
+	  tmp = build_function_type_list (void_type_node,
+					  ptr_type_node, ptr_type_node,
+					  cleanup_type, NULL_TREE);
+	  fn = push_throw_library_fn (fn, tmp);
+	}
+
+      /* [except.throw]
+
+	 A throw-expression initializes a temporary object, the type
+	 of which is determined by removing any top-level
+	 cv-qualifiers from the static type of the operand of throw
+	 and adjusting the type from "array of T" or "function return
+	 T" to "pointer to T" or "pointer to function returning T"
+	 respectively.  */
+      temp_type = is_bitfield_expr_with_lowered_type (exp);
+      if (!temp_type)
+	temp_type = type_decays_to (TREE_TYPE (exp));
+
+      /* OK, this is kind of wacky.  The standard says that we call
+	 terminate when the exception handling mechanism, after
+	 completing evaluation of the expression to be thrown but
+	 before the exception is caught (_except.throw_), calls a
+	 user function that exits via an uncaught exception.
+
+	 So we have to protect the actual initialization of the
+	 exception object with terminate(), but evaluate the
+	 expression first.  Since there could be temps in the
+	 expression, we need to handle that, too.  We also expand
+	 the call to __cxa_allocate_exception first (which doesn't
+	 matter, since it can't throw).  */
+
+      /* Allocate the space for the exception.  */
+      allocate_expr = do_allocate_exception (temp_type);
+      allocate_expr = get_target_expr (allocate_expr);
+      ptr = TARGET_EXPR_SLOT (allocate_expr);
+      TARGET_EXPR_CLEANUP (allocate_expr) = do_free_exception (ptr);
+      CLEANUP_EH_ONLY (allocate_expr) = 1;
+
+      object = build_nop (build_pointer_type (temp_type), ptr);
+      object = cp_build_indirect_ref (object, RO_NULL, tf_warning_or_error);
+
+      /* And initialize the exception object.  */
+      if (CLASS_TYPE_P (temp_type))
+	{
+	  int flags = LOOKUP_NORMAL | LOOKUP_ONLYCONVERTING;
+	  VEC(tree,gc) *exp_vec;
+
+	  /* Under C++0x [12.8/16 class.copy], a thrown lvalue is sometimes
+	     treated as an rvalue for the purposes of overload resolution
+	     to favor move constructors over copy constructors.  */
+	  if (/* Must be a local, automatic variable.  */
+	      TREE_CODE (exp) == VAR_DECL
+	      && DECL_CONTEXT (exp) == current_function_decl
+	      && ! TREE_STATIC (exp)
+	      /* The variable must not have the `volatile' qualifier.  */
+	      && !(cp_type_quals (TREE_TYPE (exp)) & TYPE_QUAL_VOLATILE))
+	    flags = flags | LOOKUP_PREFER_RVALUE;
+
+	  /* Call the copy constructor.  */
+	  exp_vec = make_tree_vector_single (exp);
+	  exp = (build_special_member_call
+		 (object, complete_ctor_identifier, &exp_vec,
+		  TREE_TYPE (object), flags, tf_warning_or_error));
+	  release_tree_vector (exp_vec);
+	  if (exp == error_mark_node)
+	    {
+	      error ("  in thrown expression");
+	      return error_mark_node;
+	    }
+	}
+      else
+	{
+	  tmp = decay_conversion (exp);
+	  if (tmp == error_mark_node)
+	    return error_mark_node;
+	  exp = build2 (INIT_EXPR, temp_type, object, tmp);
+	}
+
+      /* Mark any cleanups from the initialization as MUST_NOT_THROW, since
+	 they are run after the exception object is initialized.  */
+      cp_walk_tree_without_duplicates (&exp, wrap_cleanups_r, 0);
+
+      /* Prepend the allocation.  */
+      exp = build2 (COMPOUND_EXPR, TREE_TYPE (exp), allocate_expr, exp);
+
+      /* Force all the cleanups to be evaluated here so that we don't have
+	 to do them during unwinding.  */
+      exp = build1 (CLEANUP_POINT_EXPR, void_type_node, exp);
+
+      throw_type = build_eh_type_type (prepare_eh_type (TREE_TYPE (object)));
+
+      if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (object)))
+	{
+	  cleanup = lookup_fnfields (TYPE_BINFO (TREE_TYPE (object)),
+				     complete_dtor_identifier, 0);
+	  cleanup = BASELINK_FUNCTIONS (cleanup);
+	  mark_used (cleanup);
+	  cxx_mark_addressable (cleanup);
+	  /* Pretend it's a normal function.  */
+	  cleanup = build1 (ADDR_EXPR, cleanup_type, cleanup);
+	}
+      else
+	cleanup = build_int_cst (cleanup_type, 0);
+
+      /* ??? Indicate that this function call throws throw_type.  */
+      tmp = cp_build_function_call_nary (fn, tf_warning_or_error,
+					 ptr, throw_type, cleanup, NULL_TREE);
+
+      /* Tack on the initialization stuff.  */
+      exp = build2 (COMPOUND_EXPR, TREE_TYPE (tmp), exp, tmp);
+    }
+  else
+    {
+      /* Rethrow current exception.  */
+
+      tree fn = get_identifier ("__cxa_rethrow");
+      if (!get_global_value_if_present (fn, &fn))
+	{
+	  /* Declare void __cxa_rethrow (void).  */
+	  fn = push_throw_library_fn
+	    (fn, build_function_type_list (void_type_node, NULL_TREE));
+	}
+
+      /* ??? Indicate that this function call allows exceptions of the type
+	 of the enclosing catch block (if known).  */
+      exp = cp_build_function_call_vec (fn, NULL, tf_warning_or_error);
+    }
+
+  exp = build1 (THROW_EXPR, void_type_node, exp);
+  SET_EXPR_LOCATION (exp, input_location);
+
+  return exp;
+}
+
+/* Make sure TYPE is complete, pointer to complete, reference to
+   complete, or pointer to cv void. Issue diagnostic on failure.
+   Return the zero on failure and nonzero on success. FROM can be
+   the expr or decl from whence TYPE came, if available.  */
+
+static int
+complete_ptr_ref_or_void_ptr_p (tree type, tree from)
+{
+  int is_ptr;
+
+  /* Check complete.  */
+  type = complete_type_or_else (type, from);
+  if (!type)
+    return 0;
+
+  /* Or a pointer or ref to one, or cv void *.  */
+  is_ptr = TREE_CODE (type) == POINTER_TYPE;
+  if (is_ptr || TREE_CODE (type) == REFERENCE_TYPE)
+    {
+      tree core = TREE_TYPE (type);
+
+      if (is_ptr && VOID_TYPE_P (core))
+	/* OK */;
+      else if (!complete_type_or_else (core, from))
+	return 0;
+    }
+  return 1;
+}
+
+/* Return truth-value if EXPRESSION is admissible in throw-expression,
+   i.e. if it is not of incomplete type or a pointer/reference to such
+   a type or of an abstract class type.  */
+
+static bool
+is_admissible_throw_operand (tree expr)
+{
+  tree type = TREE_TYPE (expr);
+
+  /* 15.1/4 [...] The type of the throw-expression shall not be an
+	    incomplete type, or a pointer or a reference to an incomplete
+	    type, other than void*, const void*, volatile void*, or
+	    const volatile void*.  Except for these restriction and the
+	    restrictions on type matching mentioned in 15.3, the operand
+	    of throw is treated exactly as a function argument in a call
+	    (5.2.2) or the operand of a return statement.  */
+  if (!complete_ptr_ref_or_void_ptr_p (type, expr))
+    return false;
+
+  /* 10.4/3 An abstract class shall not be used as a parameter type,
+	    as a function return type or as type of an explicit
+	    conversion.  */
+  else if (CLASS_TYPE_P (type) && CLASSTYPE_PURE_VIRTUALS (type))
+    {
+      error ("expression %qE of abstract class type %qT cannot "
+	     "be used in throw-expression", expr, type);
+      return false;
+    }
+
+  return true;
+}
+
+/* Returns nonzero if FN is a declaration of a standard C library
+   function which is known not to throw.
+
+   [lib.res.on.exception.handling]: None of the functions from the
+   Standard C library shall report an error by throwing an
+   exception, unless it calls a program-supplied function that
+   throws an exception.  */
+
+#include "cfns.h"
+
+int
+nothrow_libfn_p (const_tree fn)
+{
+  tree id;
+
+  if (TREE_PUBLIC (fn)
+      && DECL_EXTERNAL (fn)
+      && DECL_NAMESPACE_SCOPE_P (fn)
+      && DECL_EXTERN_C_P (fn))
+    /* OK */;
+  else
+    /* Can't be a C library function.  */
+    return 0;
+
+  /* Being a C library function, DECL_ASSEMBLER_NAME == DECL_NAME
+     unless the system headers are playing rename tricks, and if
+     they are, we don't want to be confused by them.  */
+  id = DECL_NAME (fn);
+  return !!libc_name_p (IDENTIFIER_POINTER (id), IDENTIFIER_LENGTH (id));
+}
+
+/* Returns nonzero if an exception of type FROM will be caught by a
+   handler for type TO, as per [except.handle].  */
+
+static int
+can_convert_eh (tree to, tree from)
+{
+  to = non_reference (to);
+  from = non_reference (from);
+
+  if (TREE_CODE (to) == POINTER_TYPE && TREE_CODE (from) == POINTER_TYPE)
+    {
+      to = TREE_TYPE (to);
+      from = TREE_TYPE (from);
+
+      if (! at_least_as_qualified_p (to, from))
+	return 0;
+
+      if (TREE_CODE (to) == VOID_TYPE)
+	return 1;
+
+      /* Else fall through.  */
+    }
+
+  if (CLASS_TYPE_P (to) && CLASS_TYPE_P (from)
+      && PUBLICLY_UNIQUELY_DERIVED_P (to, from))
+    return 1;
+
+  return 0;
+}
+
+/* Check whether any of the handlers in I are shadowed by another handler
+   accepting TYPE.  Note that the shadowing may not be complete; even if
+   an exception of type B would be caught by a handler for A, there could
+   be a derived class C for which A is an ambiguous base but B is not, so
+   the handler for B would catch an exception of type C.  */
+
+static void
+check_handlers_1 (tree master, tree_stmt_iterator i)
+{
+  tree type = TREE_TYPE (master);
+
+  for (; !tsi_end_p (i); tsi_next (&i))
+    {
+      tree handler = tsi_stmt (i);
+      if (TREE_TYPE (handler) && can_convert_eh (type, TREE_TYPE (handler)))
+	{
+	  warning_at (EXPR_LOCATION (handler), 0,
+		      "exception of type %qT will be caught",
+		      TREE_TYPE (handler));
+	  warning_at (EXPR_LOCATION (master), 0,
+		      "   by earlier handler for %qT", type);
+	  break;
+	}
+    }
+}
+
+/* Given a STATEMENT_LIST of HANDLERs, make sure that they're OK.  */
+
+void
+check_handlers (tree handlers)
+{
+  tree_stmt_iterator i;
+
+  /* If we don't have a STATEMENT_LIST, then we've just got one
+     handler, and thus nothing to warn about.  */
+  if (TREE_CODE (handlers) != STATEMENT_LIST)
+    return;
+
+  i = tsi_start (handlers);
+  if (!tsi_end_p (i))
+    while (1)
+      {
+	tree handler = tsi_stmt (i);
+	tsi_next (&i);
+
+	/* No more handlers; nothing to shadow.  */
+	if (tsi_end_p (i))
+	  break;
+	if (TREE_TYPE (handler) == NULL_TREE)
+	  permerror (EXPR_LOCATION (handler), "%<...%>"
+		     " handler must be the last handler for its try block");
+	else
+	  check_handlers_1 (handler, i);
+      }
+}
+
+/* walk_tree helper for finish_noexcept_expr.  Returns non-null if the
+   expression *TP causes the noexcept operator to evaluate to false.
+
+   5.3.7 [expr.noexcept]: The result of the noexcept operator is false if
+   in a potentially-evaluated context the expression would contain
+   * a potentially evaluated call to a function, member function,
+     function pointer, or member function pointer that does not have a
+     non-throwing exception-specification (15.4),
+   * a potentially evaluated throw-expression (15.1),
+   * a potentially evaluated dynamic_cast expression dynamic_cast<T>(v),
+     where T is a reference type, that requires a run-time check (5.2.7), or
+   * a potentially evaluated typeid expression (5.2.8) applied to a glvalue
+     expression whose type is a polymorphic class type (10.3).  */
+
+static tree
+check_noexcept_r (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
+		  void *data ATTRIBUTE_UNUSED)
+{
+  tree t = *tp;
+  enum tree_code code = TREE_CODE (t);
+  if (code == CALL_EXPR
+      || code == AGGR_INIT_EXPR)
+    {
+      /* We can only use the exception specification of the called function
+	 for determining the value of a noexcept expression; we can't use
+	 TREE_NOTHROW, as it might have a different value in another
+	 translation unit, creating ODR problems.
+
+         We could use TREE_NOTHROW (t) for !TREE_PUBLIC fns, though... */
+      tree fn = (code == AGGR_INIT_EXPR
+		 ? AGGR_INIT_EXPR_FN (t) : CALL_EXPR_FN (t));
+      tree type = TREE_TYPE (TREE_TYPE (fn));
+
+      STRIP_NOPS (fn);
+      if (TREE_CODE (fn) == ADDR_EXPR)
+	fn = TREE_OPERAND (fn, 0);
+      if (TREE_CODE (fn) == FUNCTION_DECL)
+	{
+	  /* We do use TREE_NOTHROW for ABI internals like __dynamic_cast,
+	     and for C library functions known not to throw.  */
+	  if (DECL_EXTERN_C_P (fn)
+	      && (DECL_ARTIFICIAL (fn)
+		  || nothrow_libfn_p (fn)))
+	    return TREE_NOTHROW (fn) ? NULL_TREE : fn;
+	  /* A call to a constexpr function is noexcept if the call
+	     is a constant expression.  */
+	  if (DECL_DECLARED_CONSTEXPR_P (fn)
+	      && is_sub_constant_expr (t))
+	    return NULL_TREE;
+	}
+      if (!TYPE_NOTHROW_P (type))
+	return fn;
+    }
+
+  return NULL_TREE;
+}
+
+/* If a function that causes a noexcept-expression to be false isn't
+   defined yet, remember it and check it for TREE_NOTHROW again at EOF.  */
+
+typedef struct GTY(()) pending_noexcept {
+  tree fn;
+  location_t loc;
+} pending_noexcept;
+DEF_VEC_O(pending_noexcept);
+DEF_VEC_ALLOC_O(pending_noexcept,gc);
+static GTY(()) VEC(pending_noexcept,gc) *pending_noexcept_checks;
+
+/* FN is a FUNCTION_DECL that caused a noexcept-expr to be false.  Warn if
+   it can't throw.  */
+
+static void
+maybe_noexcept_warning (tree fn)
+{
+  if (TREE_NOTHROW (fn))
+    {
+      warning (OPT_Wnoexcept, "noexcept-expression evaluates to %<false%> "
+	       "because of a call to %qD", fn);
+      warning (OPT_Wnoexcept, "but %q+D does not throw; perhaps "
+	       "it should be declared %<noexcept%>", fn);
+    }
+}
+
+/* Check any functions that weren't defined earlier when they caused a
+   noexcept expression to evaluate to false.  */
+
+void
+perform_deferred_noexcept_checks (void)
+{
+  int i;
+  pending_noexcept *p;
+  location_t saved_loc = input_location;
+  FOR_EACH_VEC_ELT (pending_noexcept, pending_noexcept_checks, i, p)
+    {
+      input_location = p->loc;
+      maybe_noexcept_warning (p->fn);
+    }
+  input_location = saved_loc;
+}
+
+/* Evaluate noexcept ( EXPR ).  */
+
+tree
+finish_noexcept_expr (tree expr, tsubst_flags_t complain)
+{
+  tree fn;
+
+  if (expr == error_mark_node)
+    return error_mark_node;
+
+  if (processing_template_decl)
+    return build_min (NOEXCEPT_EXPR, boolean_type_node, expr);
+
+  fn = cp_walk_tree_without_duplicates (&expr, check_noexcept_r, 0);
+  if (fn)
+    {
+      if ((complain & tf_warning) && warn_noexcept
+	  && TREE_CODE (fn) == FUNCTION_DECL)
+	{
+	  if (!DECL_INITIAL (fn))
+	    {
+	      /* Not defined yet; check again at EOF.  */
+	      pending_noexcept *p
+		= VEC_safe_push (pending_noexcept, gc,
+				 pending_noexcept_checks, NULL);
+	      p->fn = fn;
+	      p->loc = input_location;
+	    }
+	  else
+	    maybe_noexcept_warning (fn);
+	}
+      return boolean_false_node;
+    }
+  else
+    return boolean_true_node;
+}
+
+/* Return true iff SPEC is throw() or noexcept(true).  */
+
+bool
+nothrow_spec_p (const_tree spec)
+{
+  if (spec == NULL_TREE
+      || TREE_VALUE (spec) != NULL_TREE
+      || spec == noexcept_false_spec)
+    return false;
+  if (TREE_PURPOSE (spec) == NULL_TREE
+      || spec == noexcept_true_spec)
+    return true;
+  gcc_assert (processing_template_decl
+	      || TREE_PURPOSE (spec) == error_mark_node);
+  return false;
+}
+
+/* For FUNCTION_TYPE or METHOD_TYPE, true if NODE is noexcept.  This is the
+   case for things declared noexcept(true) and, with -fnothrow-opt, for
+   throw() functions.  */
+
+bool
+type_noexcept_p (const_tree type)
+{
+  tree spec = TYPE_RAISES_EXCEPTIONS (type);
+  if (flag_nothrow_opt)
+    return nothrow_spec_p (spec);
+  else
+    return spec == noexcept_true_spec;
+}
+
+/* For FUNCTION_TYPE or METHOD_TYPE, true if NODE can throw any type,
+   i.e. no exception-specification or noexcept(false).  */
+
+bool
+type_throw_all_p (const_tree type)
+{
+  tree spec = TYPE_RAISES_EXCEPTIONS (type);
+  return spec == NULL_TREE || spec == noexcept_false_spec;
+}
+
+/* Create a representation of the noexcept-specification with
+   constant-expression of EXPR.  COMPLAIN is as for tsubst.  */
+
+tree
+build_noexcept_spec (tree expr, int complain)
+{
+  /* This isn't part of the signature, so don't bother trying to evaluate
+     it until instantiation.  */
+  if (!processing_template_decl)
+    {
+      expr = perform_implicit_conversion_flags (boolean_type_node, expr,
+						complain,
+						LOOKUP_NORMAL);
+      expr = cxx_constant_value (expr);
+    }
+  if (expr == boolean_true_node)
+    return noexcept_true_spec;
+  else if (expr == boolean_false_node)
+    return noexcept_false_spec;
+  else if (expr == error_mark_node)
+    return error_mark_node;
+  else
+    {
+      gcc_assert (processing_template_decl || expr == error_mark_node);
+      return build_tree_list (expr, NULL_TREE);
+    }
+}