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Diffstat (limited to 'libjava/verify.cc')
| -rw-r--r-- | libjava/verify.cc | 3236 |
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diff --git a/libjava/verify.cc b/libjava/verify.cc new file mode 100644 index 000000000..b002c1c0a --- /dev/null +++ b/libjava/verify.cc @@ -0,0 +1,3236 @@ +// verify.cc - verify bytecode + +/* Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation + + This file is part of libgcj. + +This software is copyrighted work licensed under the terms of the +Libgcj License. Please consult the file "LIBGCJ_LICENSE" for +details. */ + +// Written by Tom Tromey <tromey@redhat.com> + +// Define VERIFY_DEBUG to enable debugging output. + +#include <config.h> + +#include <string.h> + +#include <jvm.h> +#include <gcj/cni.h> +#include <java-insns.h> +#include <java-interp.h> + +// On Solaris 10/x86, <signal.h> indirectly includes <ia32/sys/reg.h>, which +// defines PC since g++ predefines __EXTENSIONS__. Undef here to avoid clash +// with PC member of class _Jv_BytecodeVerifier below. +#undef PC + +#ifdef INTERPRETER + +#include <java/lang/Class.h> +#include <java/lang/VerifyError.h> +#include <java/lang/Throwable.h> +#include <java/lang/reflect/Modifier.h> +#include <java/lang/StringBuffer.h> +#include <java/lang/NoClassDefFoundError.h> + +#ifdef VERIFY_DEBUG +#include <stdio.h> +#endif /* VERIFY_DEBUG */ + + +// This is used to mark states which are not scheduled for +// verification. +#define INVALID_STATE ((state *) -1) + +static void debug_print (const char *fmt, ...) + __attribute__ ((format (printf, 1, 2))); + +static inline void +debug_print (MAYBE_UNUSED const char *fmt, ...) +{ +#ifdef VERIFY_DEBUG + va_list ap; + va_start (ap, fmt); + vfprintf (stderr, fmt, ap); + va_end (ap); +#endif /* VERIFY_DEBUG */ +} + +// This started as a fairly ordinary verifier, and for the most part +// it remains so. It works in the obvious way, by modeling the effect +// of each opcode as it is encountered. For most opcodes, this is a +// straightforward operation. +// +// This verifier does not do type merging. It used to, but this +// results in difficulty verifying some relatively simple code +// involving interfaces, and it pushed some verification work into the +// interpreter. +// +// Instead of merging reference types, when we reach a point where two +// flows of control merge, we simply keep the union of reference types +// from each branch. Then, when we need to verify a fact about a +// reference on the stack (e.g., that it is compatible with the +// argument type of a method), we check to ensure that all possible +// types satisfy the requirement. +// +// Another area this verifier differs from the norm is in its handling +// of subroutines. The JVM specification has some confusing things to +// say about subroutines. For instance, it makes claims about not +// allowing subroutines to merge and it rejects recursive subroutines. +// For the most part these are red herrings; we used to try to follow +// these things but they lead to problems. For example, the notion of +// "being in a subroutine" is not well-defined: is an exception +// handler in a subroutine? If you never execute the `ret' but +// instead `goto 1' do you remain in the subroutine? +// +// For clarity on what is really required for type safety, read +// "Simple Verification Technique for Complex Java Bytecode +// Subroutines" by Alessandro Coglio. Among other things this paper +// shows that recursive subroutines are not harmful to type safety. +// We implement something similar to what he proposes. Note that this +// means that this verifier will accept code that is rejected by some +// other verifiers. +// +// For those not wanting to read the paper, the basic observation is +// that we can maintain split states in subroutines. We maintain one +// state for each calling `jsr'. In other words, we re-verify a +// subroutine once for each caller, using the exact types held by the +// callers (as opposed to the old approach of merging types and +// keeping a bitmap registering what did or did not change). This +// approach lets us continue to verify correctly even when a +// subroutine is exited via `goto' or `athrow' and not `ret'. +// +// In some other areas the JVM specification is (mildly) incorrect, +// so we diverge. For instance, you cannot +// violate type safety by allocating an object with `new' and then +// failing to initialize it, no matter how one branches or where one +// stores the uninitialized reference. See "Improving the official +// specification of Java bytecode verification" by Alessandro Coglio. +// +// Note that there's no real point in enforcing that padding bytes or +// the mystery byte of invokeinterface must be 0, but we do that +// regardless. +// +// The verifier is currently neither completely lazy nor eager when it +// comes to loading classes. It tries to represent types by name when +// possible, and then loads them when it needs to verify a fact about +// the type. Checking types by name is valid because we only use +// names which come from the current class' constant pool. Since all +// such names are looked up using the same class loader, there is no +// danger that we might be fooled into comparing different types with +// the same name. +// +// In the future we plan to allow for a completely lazy mode of +// operation, where the verifier will construct a list of type +// assertions to be checked later. +// +// Some test cases for the verifier live in the "verify" module of the +// Mauve test suite. However, some of these are presently +// (2004-01-20) believed to be incorrect. (More precisely the notion +// of "correct" is not well-defined, and this verifier differs from +// others while remaining type-safe.) Some other tests live in the +// libgcj test suite. +class _Jv_BytecodeVerifier +{ +private: + + static const int FLAG_INSN_START = 1; + static const int FLAG_BRANCH_TARGET = 2; + + struct state; + struct type; + struct linked_utf8; + struct ref_intersection; + + template<typename T> + struct linked + { + T *val; + linked<T> *next; + }; + + // The current PC. + int PC; + // The PC corresponding to the start of the current instruction. + int start_PC; + + // The current state of the stack, locals, etc. + state *current_state; + + // At each branch target we keep a linked list of all the states we + // can process at that point. We'll only have multiple states at a + // given PC if they both have different return-address types in the + // same stack or local slot. This array is indexed by PC and holds + // the list of all such states. + linked<state> **states; + + // We keep a linked list of all the states which we must reverify. + // This is the head of the list. + state *next_verify_state; + + // We keep some flags for each instruction. The values are the + // FLAG_* constants defined above. This is an array indexed by PC. + char *flags; + + // The bytecode itself. + unsigned char *bytecode; + // The exceptions. + _Jv_InterpException *exception; + + // Defining class. + jclass current_class; + // This method. + _Jv_InterpMethod *current_method; + + // A linked list of utf8 objects we allocate. + linked<_Jv_Utf8Const> *utf8_list; + + // A linked list of all ref_intersection objects we allocate. + ref_intersection *isect_list; + + // Create a new Utf-8 constant and return it. We do this to avoid + // having our Utf-8 constants prematurely collected. + _Jv_Utf8Const *make_utf8_const (char *s, int len) + { + linked<_Jv_Utf8Const> *lu = (linked<_Jv_Utf8Const> *) + _Jv_Malloc (sizeof (linked<_Jv_Utf8Const>) + + _Jv_Utf8Const::space_needed(s, len)); + _Jv_Utf8Const *r = (_Jv_Utf8Const *) (lu + 1); + r->init(s, len); + lu->val = r; + lu->next = utf8_list; + utf8_list = lu; + + return r; + } + + __attribute__ ((__noreturn__)) void verify_fail (const char *s, jint pc = -1) + { + using namespace java::lang; + StringBuffer *buf = new StringBuffer (); + + buf->append (JvNewStringLatin1 ("verification failed")); + if (pc == -1) + pc = start_PC; + if (pc != -1) + { + buf->append (JvNewStringLatin1 (" at PC ")); + buf->append (pc); + } + + _Jv_InterpMethod *method = current_method; + buf->append (JvNewStringLatin1 (" in ")); + buf->append (current_class->getName()); + buf->append ((jchar) ':'); + buf->append (method->get_method()->name->toString()); + buf->append ((jchar) '('); + buf->append (method->get_method()->signature->toString()); + buf->append ((jchar) ')'); + + buf->append (JvNewStringLatin1 (": ")); + buf->append (JvNewStringLatin1 (s)); + throw new java::lang::VerifyError (buf->toString ()); + } + + // This enum holds a list of tags for all the different types we + // need to handle. Reference types are treated specially by the + // type class. + enum type_val + { + void_type, + + // The values for primitive types are chosen to correspond to values + // specified to newarray. + boolean_type = 4, + char_type = 5, + float_type = 6, + double_type = 7, + byte_type = 8, + short_type = 9, + int_type = 10, + long_type = 11, + + // Used when overwriting second word of a double or long in the + // local variables. Also used after merging local variable states + // to indicate an unusable value. + unsuitable_type, + return_address_type, + // This is the second word of a two-word value, i.e., a double or + // a long. + continuation_type, + + // Everything after `reference_type' must be a reference type. + reference_type, + null_type, + uninitialized_reference_type + }; + + // This represents a merged class type. Some verifiers (including + // earlier versions of this one) will compute the intersection of + // two class types when merging states. However, this loses + // critical information about interfaces implemented by the various + // classes. So instead we keep track of all the actual classes that + // have been merged. + struct ref_intersection + { + // Whether or not this type has been resolved. + bool is_resolved; + + // Actual type data. + union + { + // For a resolved reference type, this is a pointer to the class. + jclass klass; + // For other reference types, this it the name of the class. + _Jv_Utf8Const *name; + } data; + + // Link to the next reference in the intersection. + ref_intersection *ref_next; + + // This is used to keep track of all the allocated + // ref_intersection objects, so we can free them. + // FIXME: we should allocate these in chunks. + ref_intersection *alloc_next; + + ref_intersection (jclass klass, _Jv_BytecodeVerifier *verifier) + : ref_next (NULL) + { + is_resolved = true; + data.klass = klass; + alloc_next = verifier->isect_list; + verifier->isect_list = this; + } + + ref_intersection (_Jv_Utf8Const *name, _Jv_BytecodeVerifier *verifier) + : ref_next (NULL) + { + is_resolved = false; + data.name = name; + alloc_next = verifier->isect_list; + verifier->isect_list = this; + } + + ref_intersection (ref_intersection *dup, ref_intersection *tail, + _Jv_BytecodeVerifier *verifier) + : ref_next (tail) + { + is_resolved = dup->is_resolved; + data = dup->data; + alloc_next = verifier->isect_list; + verifier->isect_list = this; + } + + bool equals (ref_intersection *other, _Jv_BytecodeVerifier *verifier) + { + if (! is_resolved && ! other->is_resolved + && _Jv_equalUtf8Classnames (data.name, other->data.name)) + return true; + if (! is_resolved) + resolve (verifier); + if (! other->is_resolved) + other->resolve (verifier); + return data.klass == other->data.klass; + } + + // Merge THIS type into OTHER, returning the result. This will + // return OTHER if all the classes in THIS already appear in + // OTHER. + ref_intersection *merge (ref_intersection *other, + _Jv_BytecodeVerifier *verifier) + { + ref_intersection *tail = other; + for (ref_intersection *self = this; self != NULL; self = self->ref_next) + { + bool add = true; + for (ref_intersection *iter = other; iter != NULL; + iter = iter->ref_next) + { + if (iter->equals (self, verifier)) + { + add = false; + break; + } + } + + if (add) + tail = new ref_intersection (self, tail, verifier); + } + return tail; + } + + void resolve (_Jv_BytecodeVerifier *verifier) + { + if (is_resolved) + return; + + // This is useful if you want to see which classes have to be resolved + // while doing the class verification. + debug_print("resolving class: %s\n", data.name->chars()); + + using namespace java::lang; + java::lang::ClassLoader *loader + = verifier->current_class->getClassLoaderInternal(); + + // Due to special handling in to_array() array classes will always + // be of the "L ... ;" kind. The separator char ('.' or '/' may vary + // however. + if (data.name->limit()[-1] == ';') + { + data.klass = _Jv_FindClassFromSignature (data.name->chars(), loader); + if (data.klass == NULL) + throw new java::lang::NoClassDefFoundError(data.name->toString()); + } + else + data.klass = Class::forName (_Jv_NewStringUtf8Const (data.name), + false, loader); + is_resolved = true; + } + + // See if an object of type OTHER can be assigned to an object of + // type *THIS. This might resolve classes in one chain or the + // other. + bool compatible (ref_intersection *other, + _Jv_BytecodeVerifier *verifier) + { + ref_intersection *self = this; + + for (; self != NULL; self = self->ref_next) + { + ref_intersection *other_iter = other; + + for (; other_iter != NULL; other_iter = other_iter->ref_next) + { + // Avoid resolving if possible. + if (! self->is_resolved + && ! other_iter->is_resolved + && _Jv_equalUtf8Classnames (self->data.name, + other_iter->data.name)) + continue; + + if (! self->is_resolved) + self->resolve(verifier); + + // If the LHS of the expression is of type + // java.lang.Object, assignment will succeed, no matter + // what the type of the RHS is. Using this short-cut we + // don't need to resolve the class of the RHS at + // verification time. + if (self->data.klass == &java::lang::Object::class$) + continue; + + if (! other_iter->is_resolved) + other_iter->resolve(verifier); + + if (! is_assignable_from_slow (self->data.klass, + other_iter->data.klass)) + return false; + } + } + + return true; + } + + bool isarray () + { + // assert (ref_next == NULL); + if (is_resolved) + return data.klass->isArray (); + else + return data.name->first() == '['; + } + + bool isinterface (_Jv_BytecodeVerifier *verifier) + { + // assert (ref_next == NULL); + if (! is_resolved) + resolve (verifier); + return data.klass->isInterface (); + } + + bool isabstract (_Jv_BytecodeVerifier *verifier) + { + // assert (ref_next == NULL); + if (! is_resolved) + resolve (verifier); + using namespace java::lang::reflect; + return Modifier::isAbstract (data.klass->getModifiers ()); + } + + jclass getclass (_Jv_BytecodeVerifier *verifier) + { + if (! is_resolved) + resolve (verifier); + return data.klass; + } + + int count_dimensions () + { + int ndims = 0; + if (is_resolved) + { + jclass k = data.klass; + while (k->isArray ()) + { + k = k->getComponentType (); + ++ndims; + } + } + else + { + char *p = data.name->chars(); + while (*p++ == '[') + ++ndims; + } + return ndims; + } + + void *operator new (size_t bytes) + { + return _Jv_Malloc (bytes); + } + + void operator delete (void *mem) + { + _Jv_Free (mem); + } + }; + + // Return the type_val corresponding to a primitive signature + // character. For instance `I' returns `int.class'. + type_val get_type_val_for_signature (jchar sig) + { + type_val rt; + switch (sig) + { + case 'Z': + rt = boolean_type; + break; + case 'B': + rt = byte_type; + break; + case 'C': + rt = char_type; + break; + case 'S': + rt = short_type; + break; + case 'I': + rt = int_type; + break; + case 'J': + rt = long_type; + break; + case 'F': + rt = float_type; + break; + case 'D': + rt = double_type; + break; + case 'V': + rt = void_type; + break; + default: + verify_fail ("invalid signature"); + } + return rt; + } + + // Return the type_val corresponding to a primitive class. + type_val get_type_val_for_signature (jclass k) + { + return get_type_val_for_signature ((jchar) k->method_count); + } + + // This is like _Jv_IsAssignableFrom, but it works even if SOURCE or + // TARGET haven't been prepared. + static bool is_assignable_from_slow (jclass target, jclass source) + { + // First, strip arrays. + while (target->isArray ()) + { + // If target is array, source must be as well. + if (! source->isArray ()) + return false; + target = target->getComponentType (); + source = source->getComponentType (); + } + + // Quick success. + if (target == &java::lang::Object::class$) + return true; + + do + { + if (source == target) + return true; + + if (target->isPrimitive () || source->isPrimitive ()) + return false; + + if (target->isInterface ()) + { + for (int i = 0; i < source->interface_count; ++i) + { + // We use a recursive call because we also need to + // check superinterfaces. + if (is_assignable_from_slow (target, source->getInterface (i))) + return true; + } + } + source = source->getSuperclass (); + } + while (source != NULL); + + return false; + } + + // The `type' class is used to represent a single type in the + // verifier. + struct type + { + // The type key. + type_val key; + + // For reference types, the representation of the type. + ref_intersection *klass; + + // This is used in two situations. + // + // First, when constructing a new object, it is the PC of the + // `new' instruction which created the object. We use the special + // value UNINIT to mean that this is uninitialized. The special + // value SELF is used for the case where the current method is + // itself the <init> method. the special value EITHER is used + // when we may optionally allow either an uninitialized or + // initialized reference to match. + // + // Second, when the key is return_address_type, this holds the PC + // of the instruction following the `jsr'. + int pc; + + static const int UNINIT = -2; + static const int SELF = -1; + static const int EITHER = -3; + + // Basic constructor. + type () + { + key = unsuitable_type; + klass = NULL; + pc = UNINIT; + } + + // Make a new instance given the type tag. We assume a generic + // `reference_type' means Object. + type (type_val k) + { + key = k; + // For reference_type, if KLASS==NULL then that means we are + // looking for a generic object of any kind, including an + // uninitialized reference. + klass = NULL; + pc = UNINIT; + } + + // Make a new instance given a class. + type (jclass k, _Jv_BytecodeVerifier *verifier) + { + key = reference_type; + klass = new ref_intersection (k, verifier); + pc = UNINIT; + } + + // Make a new instance given the name of a class. + type (_Jv_Utf8Const *n, _Jv_BytecodeVerifier *verifier) + { + key = reference_type; + klass = new ref_intersection (n, verifier); + pc = UNINIT; + } + + // Copy constructor. + type (const type &t) + { + key = t.key; + klass = t.klass; + pc = t.pc; + } + + // These operators are required because libgcj can't link in + // -lstdc++. + void *operator new[] (size_t bytes) + { + return _Jv_Malloc (bytes); + } + + void operator delete[] (void *mem) + { + _Jv_Free (mem); + } + + type& operator= (type_val k) + { + key = k; + klass = NULL; + pc = UNINIT; + return *this; + } + + type& operator= (const type& t) + { + key = t.key; + klass = t.klass; + pc = t.pc; + return *this; + } + + // Promote a numeric type. + type &promote () + { + if (key == boolean_type || key == char_type + || key == byte_type || key == short_type) + key = int_type; + return *this; + } + + // Mark this type as the uninitialized result of `new'. + void set_uninitialized (int npc, _Jv_BytecodeVerifier *verifier) + { + if (key == reference_type) + key = uninitialized_reference_type; + else + verifier->verify_fail ("internal error in type::uninitialized"); + pc = npc; + } + + // Mark this type as now initialized. + void set_initialized (int npc) + { + if (npc != UNINIT && pc == npc && key == uninitialized_reference_type) + { + key = reference_type; + pc = UNINIT; + } + } + + // Mark this type as a particular return address. + void set_return_address (int npc) + { + pc = npc; + } + + // Return true if this type and type OTHER are considered + // mergeable for the purposes of state merging. This is related + // to subroutine handling. For this purpose two types are + // considered unmergeable if they are both return-addresses but + // have different PCs. + bool state_mergeable_p (const type &other) const + { + return (key != return_address_type + || other.key != return_address_type + || pc == other.pc); + } + + // Return true if an object of type K can be assigned to a variable + // of type *THIS. Handle various special cases too. Might modify + // *THIS or K. Note however that this does not perform numeric + // promotion. + bool compatible (type &k, _Jv_BytecodeVerifier *verifier) + { + // Any type is compatible with the unsuitable type. + if (key == unsuitable_type) + return true; + + if (key < reference_type || k.key < reference_type) + return key == k.key; + + // The `null' type is convertible to any initialized reference + // type. + if (key == null_type) + return k.key != uninitialized_reference_type; + if (k.key == null_type) + return key != uninitialized_reference_type; + + // A special case for a generic reference. + if (klass == NULL) + return true; + if (k.klass == NULL) + verifier->verify_fail ("programmer error in type::compatible"); + + // Handle the special 'EITHER' case, which is only used in a + // special case of 'putfield'. Note that we only need to handle + // this on the LHS of a check. + if (! isinitialized () && pc == EITHER) + { + // If the RHS is uninitialized, it must be an uninitialized + // 'this'. + if (! k.isinitialized () && k.pc != SELF) + return false; + } + else if (isinitialized () != k.isinitialized ()) + { + // An initialized type and an uninitialized type are not + // otherwise compatible. + return false; + } + else + { + // Two uninitialized objects are compatible if either: + // * The PCs are identical, or + // * One PC is UNINIT. + if (! isinitialized ()) + { + if (pc != k.pc && pc != UNINIT && k.pc != UNINIT) + return false; + } + } + + return klass->compatible(k.klass, verifier); + } + + bool equals (const type &other, _Jv_BytecodeVerifier *vfy) + { + // Only works for reference types. + if ((key != reference_type + && key != uninitialized_reference_type) + || (other.key != reference_type + && other.key != uninitialized_reference_type)) + return false; + // Only for single-valued types. + if (klass->ref_next || other.klass->ref_next) + return false; + return klass->equals (other.klass, vfy); + } + + bool isvoid () const + { + return key == void_type; + } + + bool iswide () const + { + return key == long_type || key == double_type; + } + + // Return number of stack or local variable slots taken by this + // type. + int depth () const + { + return iswide () ? 2 : 1; + } + + bool isarray () const + { + // We treat null_type as not an array. This is ok based on the + // current uses of this method. + if (key == reference_type) + return klass->isarray (); + return false; + } + + bool isnull () const + { + return key == null_type; + } + + bool isinterface (_Jv_BytecodeVerifier *verifier) + { + if (key != reference_type) + return false; + return klass->isinterface (verifier); + } + + bool isabstract (_Jv_BytecodeVerifier *verifier) + { + if (key != reference_type) + return false; + return klass->isabstract (verifier); + } + + // Return the element type of an array. + type element_type (_Jv_BytecodeVerifier *verifier) + { + if (key != reference_type) + verifier->verify_fail ("programmer error in type::element_type()", -1); + + jclass k = klass->getclass (verifier)->getComponentType (); + if (k->isPrimitive ()) + return type (verifier->get_type_val_for_signature (k)); + return type (k, verifier); + } + + // Return the array type corresponding to an initialized + // reference. We could expand this to work for other kinds of + // types, but currently we don't need to. + type to_array (_Jv_BytecodeVerifier *verifier) + { + if (key != reference_type) + verifier->verify_fail ("internal error in type::to_array()"); + + // In case the class is already resolved we can simply ask the runtime + // to give us the array version. + // If it is not resolved we prepend "[" to the classname to make the + // array usage verification more lazy. In other words: makes new Foo[300] + // pass the verifier if Foo.class is missing. + if (klass->is_resolved) + { + jclass k = klass->getclass (verifier); + + return type (_Jv_GetArrayClass (k, k->getClassLoaderInternal()), + verifier); + } + else + { + int len = klass->data.name->len(); + + // If the classname is given in the Lp1/p2/cn; format we only need + // to add a leading '['. The same procedure has to be done for + // primitive arrays (ie. provided "[I", the result should be "[[I". + // If the classname is given as p1.p2.cn we have to embed it into + // "[L" and ';'. + if (klass->data.name->limit()[-1] == ';' || + _Jv_isPrimitiveOrDerived(klass->data.name)) + { + // Reserves space for leading '[' and trailing '\0' . + char arrayName[len + 2]; + + arrayName[0] = '['; + strcpy(&arrayName[1], klass->data.name->chars()); + +#ifdef VERIFY_DEBUG + // This is only needed when we want to print the string to the + // screen while debugging. + arrayName[len + 1] = '\0'; + + debug_print("len: %d - old: '%s' - new: '%s'\n", len, klass->data.name->chars(), arrayName); +#endif + + return type (verifier->make_utf8_const( arrayName, len + 1 ), + verifier); + } + else + { + // Reserves space for leading "[L" and trailing ';' and '\0' . + char arrayName[len + 4]; + + arrayName[0] = '['; + arrayName[1] = 'L'; + strcpy(&arrayName[2], klass->data.name->chars()); + arrayName[len + 2] = ';'; + +#ifdef VERIFY_DEBUG + // This is only needed when we want to print the string to the + // screen while debugging. + arrayName[len + 3] = '\0'; + + debug_print("len: %d - old: '%s' - new: '%s'\n", len, klass->data.name->chars(), arrayName); +#endif + + return type (verifier->make_utf8_const( arrayName, len + 3 ), + verifier); + } + } + + } + + bool isreference () const + { + return key >= reference_type; + } + + int get_pc () const + { + return pc; + } + + bool isinitialized () const + { + return key == reference_type || key == null_type; + } + + bool isresolved () const + { + return (key == reference_type + || key == null_type + || key == uninitialized_reference_type); + } + + void verify_dimensions (int ndims, _Jv_BytecodeVerifier *verifier) + { + // The way this is written, we don't need to check isarray(). + if (key != reference_type) + verifier->verify_fail ("internal error in verify_dimensions:" + " not a reference type"); + + if (klass->count_dimensions () < ndims) + verifier->verify_fail ("array type has fewer dimensions" + " than required"); + } + + // Merge OLD_TYPE into this. On error throw exception. Return + // true if the merge caused a type change. + bool merge (type& old_type, bool local_semantics, + _Jv_BytecodeVerifier *verifier) + { + bool changed = false; + bool refo = old_type.isreference (); + bool refn = isreference (); + if (refo && refn) + { + if (old_type.key == null_type) + ; + else if (key == null_type) + { + *this = old_type; + changed = true; + } + else if (isinitialized () != old_type.isinitialized ()) + verifier->verify_fail ("merging initialized and uninitialized types"); + else + { + if (! isinitialized ()) + { + if (pc == UNINIT) + pc = old_type.pc; + else if (old_type.pc == UNINIT) + ; + else if (pc != old_type.pc) + verifier->verify_fail ("merging different uninitialized types"); + } + + ref_intersection *merged = old_type.klass->merge (klass, + verifier); + if (merged != klass) + { + klass = merged; + changed = true; + } + } + } + else if (refo || refn || key != old_type.key) + { + if (local_semantics) + { + // If we already have an `unsuitable' type, then we + // don't need to change again. + if (key != unsuitable_type) + { + key = unsuitable_type; + changed = true; + } + } + else + verifier->verify_fail ("unmergeable type"); + } + return changed; + } + +#ifdef VERIFY_DEBUG + void print (void) const + { + char c = '?'; + switch (key) + { + case boolean_type: c = 'Z'; break; + case byte_type: c = 'B'; break; + case char_type: c = 'C'; break; + case short_type: c = 'S'; break; + case int_type: c = 'I'; break; + case long_type: c = 'J'; break; + case float_type: c = 'F'; break; + case double_type: c = 'D'; break; + case void_type: c = 'V'; break; + case unsuitable_type: c = '-'; break; + case return_address_type: c = 'r'; break; + case continuation_type: c = '+'; break; + case reference_type: c = 'L'; break; + case null_type: c = '@'; break; + case uninitialized_reference_type: c = 'U'; break; + } + debug_print ("%c", c); + } +#endif /* VERIFY_DEBUG */ + }; + + // This class holds all the state information we need for a given + // location. + struct state + { + // The current top of the stack, in terms of slots. + int stacktop; + // The current depth of the stack. This will be larger than + // STACKTOP when wide types are on the stack. + int stackdepth; + // The stack. + type *stack; + // The local variables. + type *locals; + // We keep track of the type of `this' specially. This is used to + // ensure that an instance initializer invokes another initializer + // on `this' before returning. We must keep track of this + // specially because otherwise we might be confused by code which + // assigns to locals[0] (overwriting `this') and then returns + // without really initializing. + type this_type; + + // The PC for this state. This is only valid on states which are + // permanently attached to a given PC. For an object like + // `current_state', which is used transiently, this has no + // meaning. + int pc; + // We keep a linked list of all states requiring reverification. + // If this is the special value INVALID_STATE then this state is + // not on the list. NULL marks the end of the linked list. + state *next; + + // NO_NEXT is the PC value meaning that a new state must be + // acquired from the verification list. + static const int NO_NEXT = -1; + + state () + : this_type () + { + stack = NULL; + locals = NULL; + next = INVALID_STATE; + } + + state (int max_stack, int max_locals) + : this_type () + { + stacktop = 0; + stackdepth = 0; + stack = new type[max_stack]; + for (int i = 0; i < max_stack; ++i) + stack[i] = unsuitable_type; + locals = new type[max_locals]; + for (int i = 0; i < max_locals; ++i) + locals[i] = unsuitable_type; + pc = NO_NEXT; + next = INVALID_STATE; + } + + state (const state *orig, int max_stack, int max_locals) + { + stack = new type[max_stack]; + locals = new type[max_locals]; + copy (orig, max_stack, max_locals); + pc = NO_NEXT; + next = INVALID_STATE; + } + + ~state () + { + if (stack) + delete[] stack; + if (locals) + delete[] locals; + } + + void *operator new[] (size_t bytes) + { + return _Jv_Malloc (bytes); + } + + void operator delete[] (void *mem) + { + _Jv_Free (mem); + } + + void *operator new (size_t bytes) + { + return _Jv_Malloc (bytes); + } + + void operator delete (void *mem) + { + _Jv_Free (mem); + } + + void copy (const state *copy, int max_stack, int max_locals) + { + stacktop = copy->stacktop; + stackdepth = copy->stackdepth; + for (int i = 0; i < max_stack; ++i) + stack[i] = copy->stack[i]; + for (int i = 0; i < max_locals; ++i) + locals[i] = copy->locals[i]; + + this_type = copy->this_type; + // Don't modify `next' or `pc'. + } + + // Modify this state to reflect entry to an exception handler. + void set_exception (type t, int max_stack) + { + stackdepth = 1; + stacktop = 1; + stack[0] = t; + for (int i = stacktop; i < max_stack; ++i) + stack[i] = unsuitable_type; + } + + inline int get_pc () const + { + return pc; + } + + void set_pc (int npc) + { + pc = npc; + } + + // Merge STATE_OLD into this state. Destructively modifies this + // state. Returns true if the new state was in fact changed. + // Will throw an exception if the states are not mergeable. + bool merge (state *state_old, int max_locals, + _Jv_BytecodeVerifier *verifier) + { + bool changed = false; + + // Special handling for `this'. If one or the other is + // uninitialized, then the merge is uninitialized. + if (this_type.isinitialized ()) + this_type = state_old->this_type; + + // Merge stacks. + if (state_old->stacktop != stacktop) // FIXME stackdepth instead? + verifier->verify_fail ("stack sizes differ"); + for (int i = 0; i < state_old->stacktop; ++i) + { + if (stack[i].merge (state_old->stack[i], false, verifier)) + changed = true; + } + + // Merge local variables. + for (int i = 0; i < max_locals; ++i) + { + if (locals[i].merge (state_old->locals[i], true, verifier)) + changed = true; + } + + return changed; + } + + // Ensure that `this' has been initialized. + void check_this_initialized (_Jv_BytecodeVerifier *verifier) + { + if (this_type.isreference () && ! this_type.isinitialized ()) + verifier->verify_fail ("`this' is uninitialized"); + } + + // Set type of `this'. + void set_this_type (const type &k) + { + this_type = k; + } + + // Mark each `new'd object we know of that was allocated at PC as + // initialized. + void set_initialized (int pc, int max_locals) + { + for (int i = 0; i < stacktop; ++i) + stack[i].set_initialized (pc); + for (int i = 0; i < max_locals; ++i) + locals[i].set_initialized (pc); + this_type.set_initialized (pc); + } + + // This tests to see whether two states can be considered "merge + // compatible". If both states have a return-address in the same + // slot, and the return addresses are different, then they are not + // compatible and we must not try to merge them. + bool state_mergeable_p (state *other, int max_locals, + _Jv_BytecodeVerifier *verifier) + { + // This is tricky: if the stack sizes differ, then not only are + // these not mergeable, but in fact we should give an error, as + // we've found two execution paths that reach a branch target + // with different stack depths. FIXME stackdepth instead? + if (stacktop != other->stacktop) + verifier->verify_fail ("stack sizes differ"); + + for (int i = 0; i < stacktop; ++i) + if (! stack[i].state_mergeable_p (other->stack[i])) + return false; + for (int i = 0; i < max_locals; ++i) + if (! locals[i].state_mergeable_p (other->locals[i])) + return false; + return true; + } + + void reverify (_Jv_BytecodeVerifier *verifier) + { + if (next == INVALID_STATE) + { + next = verifier->next_verify_state; + verifier->next_verify_state = this; + } + } + +#ifdef VERIFY_DEBUG + void print (const char *leader, int pc, + int max_stack, int max_locals) const + { + debug_print ("%s [%4d]: [stack] ", leader, pc); + int i; + for (i = 0; i < stacktop; ++i) + stack[i].print (); + for (; i < max_stack; ++i) + debug_print ("."); + debug_print (" [local] "); + for (i = 0; i < max_locals; ++i) + locals[i].print (); + debug_print (" | %p\n", this); + } +#else + inline void print (const char *, int, int, int) const + { + } +#endif /* VERIFY_DEBUG */ + }; + + type pop_raw () + { + if (current_state->stacktop <= 0) + verify_fail ("stack empty"); + type r = current_state->stack[--current_state->stacktop]; + current_state->stackdepth -= r.depth (); + if (current_state->stackdepth < 0) + verify_fail ("stack empty", start_PC); + return r; + } + + type pop32 () + { + type r = pop_raw (); + if (r.iswide ()) + verify_fail ("narrow pop of wide type"); + return r; + } + + type pop_type (type match) + { + match.promote (); + type t = pop_raw (); + if (! match.compatible (t, this)) + verify_fail ("incompatible type on stack"); + return t; + } + + // Pop a reference which is guaranteed to be initialized. MATCH + // doesn't have to be a reference type; in this case this acts like + // pop_type. + type pop_init_ref (type match) + { + type t = pop_raw (); + if (t.isreference () && ! t.isinitialized ()) + verify_fail ("initialized reference required"); + else if (! match.compatible (t, this)) + verify_fail ("incompatible type on stack"); + return t; + } + + // Pop a reference type or a return address. + type pop_ref_or_return () + { + type t = pop_raw (); + if (! t.isreference () && t.key != return_address_type) + verify_fail ("expected reference or return address on stack"); + return t; + } + + void push_type (type t) + { + // If T is a numeric type like short, promote it to int. + t.promote (); + + int depth = t.depth (); + if (current_state->stackdepth + depth > current_method->max_stack) + verify_fail ("stack overflow"); + current_state->stack[current_state->stacktop++] = t; + current_state->stackdepth += depth; + } + + void set_variable (int index, type t) + { + // If T is a numeric type like short, promote it to int. + t.promote (); + + int depth = t.depth (); + if (index > current_method->max_locals - depth) + verify_fail ("invalid local variable"); + current_state->locals[index] = t; + + if (depth == 2) + current_state->locals[index + 1] = continuation_type; + if (index > 0 && current_state->locals[index - 1].iswide ()) + current_state->locals[index - 1] = unsuitable_type; + } + + type get_variable (int index, type t) + { + int depth = t.depth (); + if (index > current_method->max_locals - depth) + verify_fail ("invalid local variable"); + if (! t.compatible (current_state->locals[index], this)) + verify_fail ("incompatible type in local variable"); + if (depth == 2) + { + type t (continuation_type); + if (! current_state->locals[index + 1].compatible (t, this)) + verify_fail ("invalid local variable"); + } + return current_state->locals[index]; + } + + // Make sure ARRAY is an array type and that its elements are + // compatible with type ELEMENT. Returns the actual element type. + type require_array_type (type array, type element) + { + // An odd case. Here we just pretend that everything went ok. If + // the requested element type is some kind of reference, return + // the null type instead. + if (array.isnull ()) + return element.isreference () ? type (null_type) : element; + + if (! array.isarray ()) + verify_fail ("array required"); + + type t = array.element_type (this); + if (! element.compatible (t, this)) + { + // Special case for byte arrays, which must also be boolean + // arrays. + bool ok = true; + if (element.key == byte_type) + { + type e2 (boolean_type); + ok = e2.compatible (t, this); + } + if (! ok) + verify_fail ("incompatible array element type"); + } + + // Return T and not ELEMENT, because T might be specialized. + return t; + } + + jint get_byte () + { + if (PC >= current_method->code_length) + verify_fail ("premature end of bytecode"); + return (jint) bytecode[PC++] & 0xff; + } + + jint get_ushort () + { + jint b1 = get_byte (); + jint b2 = get_byte (); + return (jint) ((b1 << 8) | b2) & 0xffff; + } + + jint get_short () + { + jint b1 = get_byte (); + jint b2 = get_byte (); + jshort s = (b1 << 8) | b2; + return (jint) s; + } + + jint get_int () + { + jint b1 = get_byte (); + jint b2 = get_byte (); + jint b3 = get_byte (); + jint b4 = get_byte (); + return (b1 << 24) | (b2 << 16) | (b3 << 8) | b4; + } + + int compute_jump (int offset) + { + int npc = start_PC + offset; + if (npc < 0 || npc >= current_method->code_length) + verify_fail ("branch out of range", start_PC); + return npc; + } + + // Add a new state to the state list at NPC. + state *add_new_state (int npc, state *old_state) + { + state *new_state = new state (old_state, current_method->max_stack, + current_method->max_locals); + debug_print ("== New state in add_new_state\n"); + new_state->print ("New", npc, current_method->max_stack, + current_method->max_locals); + linked<state> *nlink + = (linked<state> *) _Jv_Malloc (sizeof (linked<state>)); + nlink->val = new_state; + nlink->next = states[npc]; + states[npc] = nlink; + new_state->set_pc (npc); + return new_state; + } + + // Merge the indicated state into the state at the branch target and + // schedule a new PC if there is a change. NPC is the PC of the + // branch target, and FROM_STATE is the state at the source of the + // branch. This method returns true if the destination state + // changed and requires reverification, false otherwise. + void merge_into (int npc, state *from_state) + { + // Iterate over all target states and merge our state into each, + // if applicable. FIXME one improvement we could make here is + // "state destruction". Merging a new state into an existing one + // might cause a return_address_type to be merged to + // unsuitable_type. In this case the resulting state may now be + // mergeable with other states currently held in parallel at this + // location. So in this situation we could pairwise compare and + // reduce the number of parallel states. + bool applicable = false; + for (linked<state> *iter = states[npc]; iter != NULL; iter = iter->next) + { + state *new_state = iter->val; + if (new_state->state_mergeable_p (from_state, + current_method->max_locals, this)) + { + applicable = true; + + debug_print ("== Merge states in merge_into\n"); + from_state->print ("Frm", start_PC, current_method->max_stack, + current_method->max_locals); + new_state->print (" To", npc, current_method->max_stack, + current_method->max_locals); + bool changed = new_state->merge (from_state, + current_method->max_locals, + this); + new_state->print ("New", npc, current_method->max_stack, + current_method->max_locals); + + if (changed) + new_state->reverify (this); + } + } + + if (! applicable) + { + // Either we don't yet have a state at NPC, or we have a + // return-address type that is in conflict with all existing + // state. So, we need to create a new entry. + state *new_state = add_new_state (npc, from_state); + // A new state added in this way must always be reverified. + new_state->reverify (this); + } + } + + void push_jump (int offset) + { + int npc = compute_jump (offset); + // According to the JVM Spec, we need to check for uninitialized + // objects here. However, this does not actually affect type + // safety, and the Eclipse java compiler generates code that + // violates this constraint. + merge_into (npc, current_state); + } + + void push_exception_jump (type t, int pc) + { + // According to the JVM Spec, we need to check for uninitialized + // objects here. However, this does not actually affect type + // safety, and the Eclipse java compiler generates code that + // violates this constraint. + state s (current_state, current_method->max_stack, + current_method->max_locals); + if (current_method->max_stack < 1) + verify_fail ("stack overflow at exception handler"); + s.set_exception (t, current_method->max_stack); + merge_into (pc, &s); + } + + state *pop_jump () + { + state *new_state = next_verify_state; + if (new_state == INVALID_STATE) + verify_fail ("programmer error in pop_jump"); + if (new_state != NULL) + { + next_verify_state = new_state->next; + new_state->next = INVALID_STATE; + } + return new_state; + } + + void invalidate_pc () + { + PC = state::NO_NEXT; + } + + void note_branch_target (int pc) + { + // Don't check `pc <= PC', because we've advanced PC after + // fetching the target and we haven't yet checked the next + // instruction. + if (pc < PC && ! (flags[pc] & FLAG_INSN_START)) + verify_fail ("branch not to instruction start", start_PC); + flags[pc] |= FLAG_BRANCH_TARGET; + } + + void skip_padding () + { + while ((PC % 4) > 0) + if (get_byte () != 0) + verify_fail ("found nonzero padding byte"); + } + + // Do the work for a `ret' instruction. INDEX is the index into the + // local variables. + void handle_ret_insn (int index) + { + type ret_addr = get_variable (index, return_address_type); + // It would be nice if we could do this. However, the JVM Spec + // doesn't say that this is what happens. It is implied that + // reusing a return address is invalid, but there's no actual + // prohibition against it. + // set_variable (index, unsuitable_type); + + int npc = ret_addr.get_pc (); + // We might be returning to a `jsr' that is at the end of the + // bytecode. This is ok if we never return from the called + // subroutine, but if we see this here it is an error. + if (npc >= current_method->code_length) + verify_fail ("fell off end"); + + // According to the JVM Spec, we need to check for uninitialized + // objects here. However, this does not actually affect type + // safety, and the Eclipse java compiler generates code that + // violates this constraint. + merge_into (npc, current_state); + invalidate_pc (); + } + + void handle_jsr_insn (int offset) + { + int npc = compute_jump (offset); + + // According to the JVM Spec, we need to check for uninitialized + // objects here. However, this does not actually affect type + // safety, and the Eclipse java compiler generates code that + // violates this constraint. + + // Modify our state as appropriate for entry into a subroutine. + type ret_addr (return_address_type); + ret_addr.set_return_address (PC); + push_type (ret_addr); + merge_into (npc, current_state); + invalidate_pc (); + } + + jclass construct_primitive_array_type (type_val prim) + { + jclass k = NULL; + switch (prim) + { + case boolean_type: + k = JvPrimClass (boolean); + break; + case char_type: + k = JvPrimClass (char); + break; + case float_type: + k = JvPrimClass (float); + break; + case double_type: + k = JvPrimClass (double); + break; + case byte_type: + k = JvPrimClass (byte); + break; + case short_type: + k = JvPrimClass (short); + break; + case int_type: + k = JvPrimClass (int); + break; + case long_type: + k = JvPrimClass (long); + break; + + // These aren't used here but we call them out to avoid + // warnings. + case void_type: + case unsuitable_type: + case return_address_type: + case continuation_type: + case reference_type: + case null_type: + case uninitialized_reference_type: + default: + verify_fail ("unknown type in construct_primitive_array_type"); + } + k = _Jv_GetArrayClass (k, NULL); + return k; + } + + // This pass computes the location of branch targets and also + // instruction starts. + void branch_prepass () + { + flags = (char *) _Jv_Malloc (current_method->code_length); + + for (int i = 0; i < current_method->code_length; ++i) + flags[i] = 0; + + PC = 0; + while (PC < current_method->code_length) + { + // Set `start_PC' early so that error checking can have the + // correct value. + start_PC = PC; + flags[PC] |= FLAG_INSN_START; + + java_opcode opcode = (java_opcode) bytecode[PC++]; + switch (opcode) + { + case op_nop: + case op_aconst_null: + case op_iconst_m1: + case op_iconst_0: + case op_iconst_1: + case op_iconst_2: + case op_iconst_3: + case op_iconst_4: + case op_iconst_5: + case op_lconst_0: + case op_lconst_1: + case op_fconst_0: + case op_fconst_1: + case op_fconst_2: + case op_dconst_0: + case op_dconst_1: + case op_iload_0: + case op_iload_1: + case op_iload_2: + case op_iload_3: + case op_lload_0: + case op_lload_1: + case op_lload_2: + case op_lload_3: + case op_fload_0: + case op_fload_1: + case op_fload_2: + case op_fload_3: + case op_dload_0: + case op_dload_1: + case op_dload_2: + case op_dload_3: + case op_aload_0: + case op_aload_1: + case op_aload_2: + case op_aload_3: + case op_iaload: + case op_laload: + case op_faload: + case op_daload: + case op_aaload: + case op_baload: + case op_caload: + case op_saload: + case op_istore_0: + case op_istore_1: + case op_istore_2: + case op_istore_3: + case op_lstore_0: + case op_lstore_1: + case op_lstore_2: + case op_lstore_3: + case op_fstore_0: + case op_fstore_1: + case op_fstore_2: + case op_fstore_3: + case op_dstore_0: + case op_dstore_1: + case op_dstore_2: + case op_dstore_3: + case op_astore_0: + case op_astore_1: + case op_astore_2: + case op_astore_3: + case op_iastore: + case op_lastore: + case op_fastore: + case op_dastore: + case op_aastore: + case op_bastore: + case op_castore: + case op_sastore: + case op_pop: + case op_pop2: + case op_dup: + case op_dup_x1: + case op_dup_x2: + case op_dup2: + case op_dup2_x1: + case op_dup2_x2: + case op_swap: + case op_iadd: + case op_isub: + case op_imul: + case op_idiv: + case op_irem: + case op_ishl: + case op_ishr: + case op_iushr: + case op_iand: + case op_ior: + case op_ixor: + case op_ladd: + case op_lsub: + case op_lmul: + case op_ldiv: + case op_lrem: + case op_lshl: + case op_lshr: + case op_lushr: + case op_land: + case op_lor: + case op_lxor: + case op_fadd: + case op_fsub: + case op_fmul: + case op_fdiv: + case op_frem: + case op_dadd: + case op_dsub: + case op_dmul: + case op_ddiv: + case op_drem: + case op_ineg: + case op_i2b: + case op_i2c: + case op_i2s: + case op_lneg: + case op_fneg: + case op_dneg: + case op_i2l: + case op_i2f: + case op_i2d: + case op_l2i: + case op_l2f: + case op_l2d: + case op_f2i: + case op_f2l: + case op_f2d: + case op_d2i: + case op_d2l: + case op_d2f: + case op_lcmp: + case op_fcmpl: + case op_fcmpg: + case op_dcmpl: + case op_dcmpg: + case op_monitorenter: + case op_monitorexit: + case op_ireturn: + case op_lreturn: + case op_freturn: + case op_dreturn: + case op_areturn: + case op_return: + case op_athrow: + case op_arraylength: + break; + + case op_bipush: + case op_ldc: + case op_iload: + case op_lload: + case op_fload: + case op_dload: + case op_aload: + case op_istore: + case op_lstore: + case op_fstore: + case op_dstore: + case op_astore: + case op_ret: + case op_newarray: + get_byte (); + break; + + case op_iinc: + case op_sipush: + case op_ldc_w: + case op_ldc2_w: + case op_getstatic: + case op_getfield: + case op_putfield: + case op_putstatic: + case op_new: + case op_anewarray: + case op_instanceof: + case op_checkcast: + case op_invokespecial: + case op_invokestatic: + case op_invokevirtual: + get_short (); + break; + + case op_multianewarray: + get_short (); + get_byte (); + break; + + case op_jsr: + case op_ifeq: + case op_ifne: + case op_iflt: + case op_ifge: + case op_ifgt: + case op_ifle: + case op_if_icmpeq: + case op_if_icmpne: + case op_if_icmplt: + case op_if_icmpge: + case op_if_icmpgt: + case op_if_icmple: + case op_if_acmpeq: + case op_if_acmpne: + case op_ifnull: + case op_ifnonnull: + case op_goto: + note_branch_target (compute_jump (get_short ())); + break; + + case op_tableswitch: + { + skip_padding (); + note_branch_target (compute_jump (get_int ())); + jint low = get_int (); + jint hi = get_int (); + if (low > hi) + verify_fail ("invalid tableswitch", start_PC); + for (int i = low; i <= hi; ++i) + note_branch_target (compute_jump (get_int ())); + } + break; + + case op_lookupswitch: + { + skip_padding (); + note_branch_target (compute_jump (get_int ())); + int npairs = get_int (); + if (npairs < 0) + verify_fail ("too few pairs in lookupswitch", start_PC); + while (npairs-- > 0) + { + get_int (); + note_branch_target (compute_jump (get_int ())); + } + } + break; + + case op_invokeinterface: + get_short (); + get_byte (); + get_byte (); + break; + + case op_wide: + { + opcode = (java_opcode) get_byte (); + get_short (); + if (opcode == op_iinc) + get_short (); + } + break; + + case op_jsr_w: + case op_goto_w: + note_branch_target (compute_jump (get_int ())); + break; + + // These are unused here, but we call them out explicitly + // so that -Wswitch-enum doesn't complain. + case op_putfield_1: + case op_putfield_2: + case op_putfield_4: + case op_putfield_8: + case op_putfield_a: + case op_putstatic_1: + case op_putstatic_2: + case op_putstatic_4: + case op_putstatic_8: + case op_putstatic_a: + case op_getfield_1: + case op_getfield_2s: + case op_getfield_2u: + case op_getfield_4: + case op_getfield_8: + case op_getfield_a: + case op_getstatic_1: + case op_getstatic_2s: + case op_getstatic_2u: + case op_getstatic_4: + case op_getstatic_8: + case op_getstatic_a: + case op_breakpoint: + default: + verify_fail ("unrecognized instruction in branch_prepass", + start_PC); + } + + // See if any previous branch tried to branch to the middle of + // this instruction. + for (int pc = start_PC + 1; pc < PC; ++pc) + { + if ((flags[pc] & FLAG_BRANCH_TARGET)) + verify_fail ("branch to middle of instruction", pc); + } + } + + // Verify exception handlers. + for (int i = 0; i < current_method->exc_count; ++i) + { + if (! (flags[exception[i].handler_pc.i] & FLAG_INSN_START)) + verify_fail ("exception handler not at instruction start", + exception[i].handler_pc.i); + if (! (flags[exception[i].start_pc.i] & FLAG_INSN_START)) + verify_fail ("exception start not at instruction start", + exception[i].start_pc.i); + if (exception[i].end_pc.i != current_method->code_length + && ! (flags[exception[i].end_pc.i] & FLAG_INSN_START)) + verify_fail ("exception end not at instruction start", + exception[i].end_pc.i); + + flags[exception[i].handler_pc.i] |= FLAG_BRANCH_TARGET; + } + } + + void check_pool_index (int index) + { + if (index < 0 || index >= current_class->constants.size) + verify_fail ("constant pool index out of range", start_PC); + } + + type check_class_constant (int index) + { + check_pool_index (index); + _Jv_Constants *pool = ¤t_class->constants; + if (pool->tags[index] == JV_CONSTANT_ResolvedClass) + return type (pool->data[index].clazz, this); + else if (pool->tags[index] == JV_CONSTANT_Class) + return type (pool->data[index].utf8, this); + verify_fail ("expected class constant", start_PC); + } + + type check_constant (int index) + { + check_pool_index (index); + _Jv_Constants *pool = ¤t_class->constants; + int tag = pool->tags[index]; + if (tag == JV_CONSTANT_ResolvedString || tag == JV_CONSTANT_String) + return type (&java::lang::String::class$, this); + else if (tag == JV_CONSTANT_Integer) + return type (int_type); + else if (tag == JV_CONSTANT_Float) + return type (float_type); + else if (current_method->is_15 + && (tag == JV_CONSTANT_ResolvedClass || tag == JV_CONSTANT_Class)) + return type (&java::lang::Class::class$, this); + verify_fail ("String, int, or float constant expected", start_PC); + } + + type check_wide_constant (int index) + { + check_pool_index (index); + _Jv_Constants *pool = ¤t_class->constants; + if (pool->tags[index] == JV_CONSTANT_Long) + return type (long_type); + else if (pool->tags[index] == JV_CONSTANT_Double) + return type (double_type); + verify_fail ("long or double constant expected", start_PC); + } + + // Helper for both field and method. These are laid out the same in + // the constant pool. + type handle_field_or_method (int index, int expected, + _Jv_Utf8Const **name, + _Jv_Utf8Const **fmtype) + { + check_pool_index (index); + _Jv_Constants *pool = ¤t_class->constants; + if (pool->tags[index] != expected) + verify_fail ("didn't see expected constant", start_PC); + // Once we know we have a Fieldref or Methodref we assume that it + // is correctly laid out in the constant pool. I think the code + // in defineclass.cc guarantees this. + _Jv_ushort class_index, name_and_type_index; + _Jv_loadIndexes (&pool->data[index], + class_index, + name_and_type_index); + _Jv_ushort name_index, desc_index; + _Jv_loadIndexes (&pool->data[name_and_type_index], + name_index, desc_index); + + *name = pool->data[name_index].utf8; + *fmtype = pool->data[desc_index].utf8; + + return check_class_constant (class_index); + } + + // Return field's type, compute class' type if requested. + // If PUTFIELD is true, use the special 'putfield' semantics. + type check_field_constant (int index, type *class_type = NULL, + bool putfield = false) + { + _Jv_Utf8Const *name, *field_type; + type ct = handle_field_or_method (index, + JV_CONSTANT_Fieldref, + &name, &field_type); + if (class_type) + *class_type = ct; + type result; + if (field_type->first() == '[' || field_type->first() == 'L') + result = type (field_type, this); + else + result = get_type_val_for_signature (field_type->first()); + + // We have an obscure special case here: we can use `putfield' on + // a field declared in this class, even if `this' has not yet been + // initialized. + if (putfield + && ! current_state->this_type.isinitialized () + && current_state->this_type.pc == type::SELF + && current_state->this_type.equals (ct, this) + // We don't look at the signature, figuring that if it is + // wrong we will fail during linking. FIXME? + && _Jv_Linker::has_field_p (current_class, name)) + // Note that we don't actually know whether we're going to match + // against 'this' or some other object of the same type. So, + // here we set things up so that it doesn't matter. This relies + // on knowing what our caller is up to. + class_type->set_uninitialized (type::EITHER, this); + + return result; + } + + type check_method_constant (int index, bool is_interface, + _Jv_Utf8Const **method_name, + _Jv_Utf8Const **method_signature) + { + return handle_field_or_method (index, + (is_interface + ? JV_CONSTANT_InterfaceMethodref + : JV_CONSTANT_Methodref), + method_name, method_signature); + } + + type get_one_type (char *&p) + { + char *start = p; + + int arraycount = 0; + while (*p == '[') + { + ++arraycount; + ++p; + } + + char v = *p++; + + if (v == 'L') + { + while (*p != ';') + ++p; + ++p; + _Jv_Utf8Const *name = make_utf8_const (start, p - start); + return type (name, this); + } + + // Casting to jchar here is ok since we are looking at an ASCII + // character. + type_val rt = get_type_val_for_signature (jchar (v)); + + if (arraycount == 0) + { + // Callers of this function eventually push their arguments on + // the stack. So, promote them here. + return type (rt).promote (); + } + + jclass k = construct_primitive_array_type (rt); + while (--arraycount > 0) + k = _Jv_GetArrayClass (k, NULL); + return type (k, this); + } + + void compute_argument_types (_Jv_Utf8Const *signature, + type *types) + { + char *p = signature->chars(); + + // Skip `('. + ++p; + + int i = 0; + while (*p != ')') + types[i++] = get_one_type (p); + } + + type compute_return_type (_Jv_Utf8Const *signature) + { + char *p = signature->chars(); + while (*p != ')') + ++p; + ++p; + return get_one_type (p); + } + + void check_return_type (type onstack) + { + type rt = compute_return_type (current_method->self->signature); + if (! rt.compatible (onstack, this)) + verify_fail ("incompatible return type"); + } + + // Initialize the stack for the new method. Returns true if this + // method is an instance initializer. + bool initialize_stack () + { + int var = 0; + bool is_init = _Jv_equalUtf8Consts (current_method->self->name, + gcj::init_name); + bool is_clinit = _Jv_equalUtf8Consts (current_method->self->name, + gcj::clinit_name); + + using namespace java::lang::reflect; + if (! Modifier::isStatic (current_method->self->accflags)) + { + type kurr (current_class, this); + if (is_init) + { + kurr.set_uninitialized (type::SELF, this); + is_init = true; + } + else if (is_clinit) + verify_fail ("<clinit> method must be static"); + set_variable (0, kurr); + current_state->set_this_type (kurr); + ++var; + } + else + { + if (is_init) + verify_fail ("<init> method must be non-static"); + } + + // We have to handle wide arguments specially here. + int arg_count = _Jv_count_arguments (current_method->self->signature); + type arg_types[arg_count]; + compute_argument_types (current_method->self->signature, arg_types); + for (int i = 0; i < arg_count; ++i) + { + set_variable (var, arg_types[i]); + ++var; + if (arg_types[i].iswide ()) + ++var; + } + + return is_init; + } + + void verify_instructions_0 () + { + current_state = new state (current_method->max_stack, + current_method->max_locals); + + PC = 0; + start_PC = 0; + + // True if we are verifying an instance initializer. + bool this_is_init = initialize_stack (); + + states = (linked<state> **) _Jv_Malloc (sizeof (linked<state> *) + * current_method->code_length); + for (int i = 0; i < current_method->code_length; ++i) + states[i] = NULL; + + next_verify_state = NULL; + + while (true) + { + // If the PC was invalidated, get a new one from the work list. + if (PC == state::NO_NEXT) + { + state *new_state = pop_jump (); + // If it is null, we're done. + if (new_state == NULL) + break; + + PC = new_state->get_pc (); + debug_print ("== State pop from pending list\n"); + // Set up the current state. + current_state->copy (new_state, current_method->max_stack, + current_method->max_locals); + } + else + { + // We only have to do this checking in the situation where + // control flow falls through from the previous + // instruction. Otherwise merging is done at the time we + // push the branch. Note that we'll catch the + // off-the-end problem just below. + if (PC < current_method->code_length && states[PC] != NULL) + { + // We've already visited this instruction. So merge + // the states together. It is simplest, but not most + // efficient, to just always invalidate the PC here. + merge_into (PC, current_state); + invalidate_pc (); + continue; + } + } + + // Control can't fall off the end of the bytecode. We need to + // check this in both cases, not just the fall-through case, + // because we don't check to see whether a `jsr' appears at + // the end of the bytecode until we process a `ret'. + if (PC >= current_method->code_length) + verify_fail ("fell off end"); + + // We only have to keep saved state at branch targets. If + // we're at a branch target and the state here hasn't been set + // yet, we set it now. You might notice that `ret' targets + // won't necessarily have FLAG_BRANCH_TARGET set. This + // doesn't matter, since those states will be filled in by + // merge_into. + if (states[PC] == NULL && (flags[PC] & FLAG_BRANCH_TARGET)) + add_new_state (PC, current_state); + + // Set this before handling exceptions so that debug output is + // sane. + start_PC = PC; + + // Update states for all active exception handlers. Ordinarily + // there are not many exception handlers. So we simply run + // through them all. + for (int i = 0; i < current_method->exc_count; ++i) + { + if (PC >= exception[i].start_pc.i && PC < exception[i].end_pc.i) + { + type handler (&java::lang::Throwable::class$, this); + if (exception[i].handler_type.i != 0) + handler = check_class_constant (exception[i].handler_type.i); + push_exception_jump (handler, exception[i].handler_pc.i); + } + } + + current_state->print (" ", PC, current_method->max_stack, + current_method->max_locals); + java_opcode opcode = (java_opcode) bytecode[PC++]; + switch (opcode) + { + case op_nop: + break; + + case op_aconst_null: + push_type (null_type); + break; + + case op_iconst_m1: + case op_iconst_0: + case op_iconst_1: + case op_iconst_2: + case op_iconst_3: + case op_iconst_4: + case op_iconst_5: + push_type (int_type); + break; + + case op_lconst_0: + case op_lconst_1: + push_type (long_type); + break; + + case op_fconst_0: + case op_fconst_1: + case op_fconst_2: + push_type (float_type); + break; + + case op_dconst_0: + case op_dconst_1: + push_type (double_type); + break; + + case op_bipush: + get_byte (); + push_type (int_type); + break; + + case op_sipush: + get_short (); + push_type (int_type); + break; + + case op_ldc: + push_type (check_constant (get_byte ())); + break; + case op_ldc_w: + push_type (check_constant (get_ushort ())); + break; + case op_ldc2_w: + push_type (check_wide_constant (get_ushort ())); + break; + + case op_iload: + push_type (get_variable (get_byte (), int_type)); + break; + case op_lload: + push_type (get_variable (get_byte (), long_type)); + break; + case op_fload: + push_type (get_variable (get_byte (), float_type)); + break; + case op_dload: + push_type (get_variable (get_byte (), double_type)); + break; + case op_aload: + push_type (get_variable (get_byte (), reference_type)); + break; + + case op_iload_0: + case op_iload_1: + case op_iload_2: + case op_iload_3: + push_type (get_variable (opcode - op_iload_0, int_type)); + break; + case op_lload_0: + case op_lload_1: + case op_lload_2: + case op_lload_3: + push_type (get_variable (opcode - op_lload_0, long_type)); + break; + case op_fload_0: + case op_fload_1: + case op_fload_2: + case op_fload_3: + push_type (get_variable (opcode - op_fload_0, float_type)); + break; + case op_dload_0: + case op_dload_1: + case op_dload_2: + case op_dload_3: + push_type (get_variable (opcode - op_dload_0, double_type)); + break; + case op_aload_0: + case op_aload_1: + case op_aload_2: + case op_aload_3: + push_type (get_variable (opcode - op_aload_0, reference_type)); + break; + case op_iaload: + pop_type (int_type); + push_type (require_array_type (pop_init_ref (reference_type), + int_type)); + break; + case op_laload: + pop_type (int_type); + push_type (require_array_type (pop_init_ref (reference_type), + long_type)); + break; + case op_faload: + pop_type (int_type); + push_type (require_array_type (pop_init_ref (reference_type), + float_type)); + break; + case op_daload: + pop_type (int_type); + push_type (require_array_type (pop_init_ref (reference_type), + double_type)); + break; + case op_aaload: + pop_type (int_type); + push_type (require_array_type (pop_init_ref (reference_type), + reference_type)); + break; + case op_baload: + pop_type (int_type); + require_array_type (pop_init_ref (reference_type), byte_type); + push_type (int_type); + break; + case op_caload: + pop_type (int_type); + require_array_type (pop_init_ref (reference_type), char_type); + push_type (int_type); + break; + case op_saload: + pop_type (int_type); + require_array_type (pop_init_ref (reference_type), short_type); + push_type (int_type); + break; + case op_istore: + set_variable (get_byte (), pop_type (int_type)); + break; + case op_lstore: + set_variable (get_byte (), pop_type (long_type)); + break; + case op_fstore: + set_variable (get_byte (), pop_type (float_type)); + break; + case op_dstore: + set_variable (get_byte (), pop_type (double_type)); + break; + case op_astore: + set_variable (get_byte (), pop_ref_or_return ()); + break; + case op_istore_0: + case op_istore_1: + case op_istore_2: + case op_istore_3: + set_variable (opcode - op_istore_0, pop_type (int_type)); + break; + case op_lstore_0: + case op_lstore_1: + case op_lstore_2: + case op_lstore_3: + set_variable (opcode - op_lstore_0, pop_type (long_type)); + break; + case op_fstore_0: + case op_fstore_1: + case op_fstore_2: + case op_fstore_3: + set_variable (opcode - op_fstore_0, pop_type (float_type)); + break; + case op_dstore_0: + case op_dstore_1: + case op_dstore_2: + case op_dstore_3: + set_variable (opcode - op_dstore_0, pop_type (double_type)); + break; + case op_astore_0: + case op_astore_1: + case op_astore_2: + case op_astore_3: + set_variable (opcode - op_astore_0, pop_ref_or_return ()); + break; + case op_iastore: + pop_type (int_type); + pop_type (int_type); + require_array_type (pop_init_ref (reference_type), int_type); + break; + case op_lastore: + pop_type (long_type); + pop_type (int_type); + require_array_type (pop_init_ref (reference_type), long_type); + break; + case op_fastore: + pop_type (float_type); + pop_type (int_type); + require_array_type (pop_init_ref (reference_type), float_type); + break; + case op_dastore: + pop_type (double_type); + pop_type (int_type); + require_array_type (pop_init_ref (reference_type), double_type); + break; + case op_aastore: + pop_type (reference_type); + pop_type (int_type); + require_array_type (pop_init_ref (reference_type), reference_type); + break; + case op_bastore: + pop_type (int_type); + pop_type (int_type); + require_array_type (pop_init_ref (reference_type), byte_type); + break; + case op_castore: + pop_type (int_type); + pop_type (int_type); + require_array_type (pop_init_ref (reference_type), char_type); + break; + case op_sastore: + pop_type (int_type); + pop_type (int_type); + require_array_type (pop_init_ref (reference_type), short_type); + break; + case op_pop: + pop32 (); + break; + case op_pop2: + { + type t = pop_raw (); + if (! t.iswide ()) + pop32 (); + } + break; + case op_dup: + { + type t = pop32 (); + push_type (t); + push_type (t); + } + break; + case op_dup_x1: + { + type t1 = pop32 (); + type t2 = pop32 (); + push_type (t1); + push_type (t2); + push_type (t1); + } + break; + case op_dup_x2: + { + type t1 = pop32 (); + type t2 = pop_raw (); + if (! t2.iswide ()) + { + type t3 = pop32 (); + push_type (t1); + push_type (t3); + } + else + push_type (t1); + push_type (t2); + push_type (t1); + } + break; + case op_dup2: + { + type t = pop_raw (); + if (! t.iswide ()) + { + type t2 = pop32 (); + push_type (t2); + push_type (t); + push_type (t2); + } + else + push_type (t); + push_type (t); + } + break; + case op_dup2_x1: + { + type t1 = pop_raw (); + type t2 = pop32 (); + if (! t1.iswide ()) + { + type t3 = pop32 (); + push_type (t2); + push_type (t1); + push_type (t3); + } + else + push_type (t1); + push_type (t2); + push_type (t1); + } + break; + case op_dup2_x2: + { + type t1 = pop_raw (); + if (t1.iswide ()) + { + type t2 = pop_raw (); + if (t2.iswide ()) + { + push_type (t1); + push_type (t2); + } + else + { + type t3 = pop32 (); + push_type (t1); + push_type (t3); + push_type (t2); + } + push_type (t1); + } + else + { + type t2 = pop32 (); + type t3 = pop_raw (); + if (t3.iswide ()) + { + push_type (t2); + push_type (t1); + } + else + { + type t4 = pop32 (); + push_type (t2); + push_type (t1); + push_type (t4); + } + push_type (t3); + push_type (t2); + push_type (t1); + } + } + break; + case op_swap: + { + type t1 = pop32 (); + type t2 = pop32 (); + push_type (t1); + push_type (t2); + } + break; + case op_iadd: + case op_isub: + case op_imul: + case op_idiv: + case op_irem: + case op_ishl: + case op_ishr: + case op_iushr: + case op_iand: + case op_ior: + case op_ixor: + pop_type (int_type); + push_type (pop_type (int_type)); + break; + case op_ladd: + case op_lsub: + case op_lmul: + case op_ldiv: + case op_lrem: + case op_land: + case op_lor: + case op_lxor: + pop_type (long_type); + push_type (pop_type (long_type)); + break; + case op_lshl: + case op_lshr: + case op_lushr: + pop_type (int_type); + push_type (pop_type (long_type)); + break; + case op_fadd: + case op_fsub: + case op_fmul: + case op_fdiv: + case op_frem: + pop_type (float_type); + push_type (pop_type (float_type)); + break; + case op_dadd: + case op_dsub: + case op_dmul: + case op_ddiv: + case op_drem: + pop_type (double_type); + push_type (pop_type (double_type)); + break; + case op_ineg: + case op_i2b: + case op_i2c: + case op_i2s: + push_type (pop_type (int_type)); + break; + case op_lneg: + push_type (pop_type (long_type)); + break; + case op_fneg: + push_type (pop_type (float_type)); + break; + case op_dneg: + push_type (pop_type (double_type)); + break; + case op_iinc: + get_variable (get_byte (), int_type); + get_byte (); + break; + case op_i2l: + pop_type (int_type); + push_type (long_type); + break; + case op_i2f: + pop_type (int_type); + push_type (float_type); + break; + case op_i2d: + pop_type (int_type); + push_type (double_type); + break; + case op_l2i: + pop_type (long_type); + push_type (int_type); + break; + case op_l2f: + pop_type (long_type); + push_type (float_type); + break; + case op_l2d: + pop_type (long_type); + push_type (double_type); + break; + case op_f2i: + pop_type (float_type); + push_type (int_type); + break; + case op_f2l: + pop_type (float_type); + push_type (long_type); + break; + case op_f2d: + pop_type (float_type); + push_type (double_type); + break; + case op_d2i: + pop_type (double_type); + push_type (int_type); + break; + case op_d2l: + pop_type (double_type); + push_type (long_type); + break; + case op_d2f: + pop_type (double_type); + push_type (float_type); + break; + case op_lcmp: + pop_type (long_type); + pop_type (long_type); + push_type (int_type); + break; + case op_fcmpl: + case op_fcmpg: + pop_type (float_type); + pop_type (float_type); + push_type (int_type); + break; + case op_dcmpl: + case op_dcmpg: + pop_type (double_type); + pop_type (double_type); + push_type (int_type); + break; + case op_ifeq: + case op_ifne: + case op_iflt: + case op_ifge: + case op_ifgt: + case op_ifle: + pop_type (int_type); + push_jump (get_short ()); + break; + case op_if_icmpeq: + case op_if_icmpne: + case op_if_icmplt: + case op_if_icmpge: + case op_if_icmpgt: + case op_if_icmple: + pop_type (int_type); + pop_type (int_type); + push_jump (get_short ()); + break; + case op_if_acmpeq: + case op_if_acmpne: + pop_type (reference_type); + pop_type (reference_type); + push_jump (get_short ()); + break; + case op_goto: + push_jump (get_short ()); + invalidate_pc (); + break; + case op_jsr: + handle_jsr_insn (get_short ()); + break; + case op_ret: + handle_ret_insn (get_byte ()); + break; + case op_tableswitch: + { + pop_type (int_type); + skip_padding (); + push_jump (get_int ()); + jint low = get_int (); + jint high = get_int (); + // Already checked LOW -vs- HIGH. + for (int i = low; i <= high; ++i) + push_jump (get_int ()); + invalidate_pc (); + } + break; + + case op_lookupswitch: + { + pop_type (int_type); + skip_padding (); + push_jump (get_int ()); + jint npairs = get_int (); + // Already checked NPAIRS >= 0. + jint lastkey = 0; + for (int i = 0; i < npairs; ++i) + { + jint key = get_int (); + if (i > 0 && key <= lastkey) + verify_fail ("lookupswitch pairs unsorted", start_PC); + lastkey = key; + push_jump (get_int ()); + } + invalidate_pc (); + } + break; + case op_ireturn: + check_return_type (pop_type (int_type)); + invalidate_pc (); + break; + case op_lreturn: + check_return_type (pop_type (long_type)); + invalidate_pc (); + break; + case op_freturn: + check_return_type (pop_type (float_type)); + invalidate_pc (); + break; + case op_dreturn: + check_return_type (pop_type (double_type)); + invalidate_pc (); + break; + case op_areturn: + check_return_type (pop_init_ref (reference_type)); + invalidate_pc (); + break; + case op_return: + // We only need to check this when the return type is + // void, because all instance initializers return void. + if (this_is_init) + current_state->check_this_initialized (this); + check_return_type (void_type); + invalidate_pc (); + break; + case op_getstatic: + push_type (check_field_constant (get_ushort ())); + break; + case op_putstatic: + pop_type (check_field_constant (get_ushort ())); + break; + case op_getfield: + { + type klass; + type field = check_field_constant (get_ushort (), &klass); + pop_type (klass); + push_type (field); + } + break; + case op_putfield: + { + type klass; + type field = check_field_constant (get_ushort (), &klass, true); + pop_type (field); + pop_type (klass); + } + break; + + case op_invokevirtual: + case op_invokespecial: + case op_invokestatic: + case op_invokeinterface: + { + _Jv_Utf8Const *method_name, *method_signature; + type class_type + = check_method_constant (get_ushort (), + opcode == op_invokeinterface, + &method_name, + &method_signature); + // NARGS is only used when we're processing + // invokeinterface. It is simplest for us to compute it + // here and then verify it later. + int nargs = 0; + if (opcode == op_invokeinterface) + { + nargs = get_byte (); + if (get_byte () != 0) + verify_fail ("invokeinterface dummy byte is wrong"); + } + + bool is_init = false; + if (_Jv_equalUtf8Consts (method_name, gcj::init_name)) + { + is_init = true; + if (opcode != op_invokespecial) + verify_fail ("can't invoke <init>"); + } + else if (method_name->first() == '<') + verify_fail ("can't invoke method starting with `<'"); + + // Pop arguments and check types. + int arg_count = _Jv_count_arguments (method_signature); + type arg_types[arg_count]; + compute_argument_types (method_signature, arg_types); + for (int i = arg_count - 1; i >= 0; --i) + { + // This is only used for verifying the byte for + // invokeinterface. + nargs -= arg_types[i].depth (); + pop_init_ref (arg_types[i]); + } + + if (opcode == op_invokeinterface + && nargs != 1) + verify_fail ("wrong argument count for invokeinterface"); + + if (opcode != op_invokestatic) + { + type t = class_type; + if (is_init) + { + // In this case the PC doesn't matter. + t.set_uninitialized (type::UNINIT, this); + // FIXME: check to make sure that the <init> + // call is to the right class. + // It must either be super or an exact class + // match. + } + type raw = pop_raw (); + if (! t.compatible (raw, this)) + verify_fail ("incompatible type on stack"); + + if (is_init) + current_state->set_initialized (raw.get_pc (), + current_method->max_locals); + } + + type rt = compute_return_type (method_signature); + if (! rt.isvoid ()) + push_type (rt); + } + break; + + case op_new: + { + type t = check_class_constant (get_ushort ()); + if (t.isarray ()) + verify_fail ("type is array"); + t.set_uninitialized (start_PC, this); + push_type (t); + } + break; + + case op_newarray: + { + int atype = get_byte (); + // We intentionally have chosen constants to make this + // valid. + if (atype < boolean_type || atype > long_type) + verify_fail ("type not primitive", start_PC); + pop_type (int_type); + type t (construct_primitive_array_type (type_val (atype)), this); + push_type (t); + } + break; + case op_anewarray: + pop_type (int_type); + push_type (check_class_constant (get_ushort ()).to_array (this)); + break; + case op_arraylength: + { + type t = pop_init_ref (reference_type); + if (! t.isarray () && ! t.isnull ()) + verify_fail ("array type expected"); + push_type (int_type); + } + break; + case op_athrow: + pop_type (type (&java::lang::Throwable::class$, this)); + invalidate_pc (); + break; + case op_checkcast: + pop_init_ref (reference_type); + push_type (check_class_constant (get_ushort ())); + break; + case op_instanceof: + pop_init_ref (reference_type); + check_class_constant (get_ushort ()); + push_type (int_type); + break; + case op_monitorenter: + pop_init_ref (reference_type); + break; + case op_monitorexit: + pop_init_ref (reference_type); + break; + case op_wide: + { + switch (get_byte ()) + { + case op_iload: + push_type (get_variable (get_ushort (), int_type)); + break; + case op_lload: + push_type (get_variable (get_ushort (), long_type)); + break; + case op_fload: + push_type (get_variable (get_ushort (), float_type)); + break; + case op_dload: + push_type (get_variable (get_ushort (), double_type)); + break; + case op_aload: + push_type (get_variable (get_ushort (), reference_type)); + break; + case op_istore: + set_variable (get_ushort (), pop_type (int_type)); + break; + case op_lstore: + set_variable (get_ushort (), pop_type (long_type)); + break; + case op_fstore: + set_variable (get_ushort (), pop_type (float_type)); + break; + case op_dstore: + set_variable (get_ushort (), pop_type (double_type)); + break; + case op_astore: + set_variable (get_ushort (), pop_init_ref (reference_type)); + break; + case op_ret: + handle_ret_insn (get_short ()); + break; + case op_iinc: + get_variable (get_ushort (), int_type); + get_short (); + break; + default: + verify_fail ("unrecognized wide instruction", start_PC); + } + } + break; + case op_multianewarray: + { + type atype = check_class_constant (get_ushort ()); + int dim = get_byte (); + if (dim < 1) + verify_fail ("too few dimensions to multianewarray", start_PC); + atype.verify_dimensions (dim, this); + for (int i = 0; i < dim; ++i) + pop_type (int_type); + push_type (atype); + } + break; + case op_ifnull: + case op_ifnonnull: + pop_type (reference_type); + push_jump (get_short ()); + break; + case op_goto_w: + push_jump (get_int ()); + invalidate_pc (); + break; + case op_jsr_w: + handle_jsr_insn (get_int ()); + break; + + // These are unused here, but we call them out explicitly + // so that -Wswitch-enum doesn't complain. + case op_putfield_1: + case op_putfield_2: + case op_putfield_4: + case op_putfield_8: + case op_putfield_a: + case op_putstatic_1: + case op_putstatic_2: + case op_putstatic_4: + case op_putstatic_8: + case op_putstatic_a: + case op_getfield_1: + case op_getfield_2s: + case op_getfield_2u: + case op_getfield_4: + case op_getfield_8: + case op_getfield_a: + case op_getstatic_1: + case op_getstatic_2s: + case op_getstatic_2u: + case op_getstatic_4: + case op_getstatic_8: + case op_getstatic_a: + case op_breakpoint: + default: + // Unrecognized opcode. + verify_fail ("unrecognized instruction in verify_instructions_0", + start_PC); + } + } + } + +public: + + void verify_instructions () + { + branch_prepass (); + verify_instructions_0 (); + } + + _Jv_BytecodeVerifier (_Jv_InterpMethod *m) + { + // We just print the text as utf-8. This is just for debugging + // anyway. + debug_print ("--------------------------------\n"); + debug_print ("-- Verifying method `%s'\n", m->self->name->chars()); + + current_method = m; + bytecode = m->bytecode (); + exception = m->exceptions (); + current_class = m->defining_class; + + states = NULL; + flags = NULL; + utf8_list = NULL; + isect_list = NULL; + } + + ~_Jv_BytecodeVerifier () + { + if (flags) + _Jv_Free (flags); + + while (utf8_list != NULL) + { + linked<_Jv_Utf8Const> *n = utf8_list->next; + _Jv_Free (utf8_list); + utf8_list = n; + } + + while (isect_list != NULL) + { + ref_intersection *next = isect_list->alloc_next; + delete isect_list; + isect_list = next; + } + + if (states) + { + for (int i = 0; i < current_method->code_length; ++i) + { + linked<state> *iter = states[i]; + while (iter != NULL) + { + linked<state> *next = iter->next; + delete iter->val; + _Jv_Free (iter); + iter = next; + } + } + _Jv_Free (states); + } + } +}; + +void +_Jv_VerifyMethod (_Jv_InterpMethod *meth) +{ + _Jv_BytecodeVerifier v (meth); + v.verify_instructions (); +} + +#endif /* INTERPRETER */ |