1 // verify.cc - verify bytecode
3 /* Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation
5 This file is part of libgcj.
7 This software is copyrighted work licensed under the terms of the
8 Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
11 // Written by Tom Tromey <tromey@redhat.com>
13 // Define VERIFY_DEBUG to enable debugging output.
19 #include <java-insns.h>
20 #include <java-interp.h>
24 #include <java/lang/Class.h>
25 #include <java/lang/VerifyError.h>
26 #include <java/lang/Throwable.h>
27 #include <java/lang/reflect/Modifier.h>
28 #include <java/lang/StringBuffer.h>
32 #endif /* VERIFY_DEBUG */
35 // This is used to mark states which are not scheduled for
37 #define INVALID_STATE ((state *) -1)
39 static void debug_print (const char *fmt, ...)
40 __attribute__ ((format (printf, 1, 2)));
43 debug_print (const char *fmt, ...)
48 vfprintf (stderr, fmt, ap);
50 #endif /* VERIFY_DEBUG */
53 // This started as a fairly ordinary verifier, and for the most part
54 // it remains so. It works in the obvious way, by modeling the effect
55 // of each opcode as it is encountered. For most opcodes, this is a
56 // straightforward operation.
58 // This verifier does not do type merging. It used to, but this
59 // results in difficulty verifying some relatively simple code
60 // involving interfaces, and it pushed some verification work into the
63 // Instead of merging reference types, when we reach a point where two
64 // flows of control merge, we simply keep the union of reference types
65 // from each branch. Then, when we need to verify a fact about a
66 // reference on the stack (e.g., that it is compatible with the
67 // argument type of a method), we check to ensure that all possible
68 // types satisfy the requirement.
70 // Another area this verifier differs from the norm is in its handling
71 // of subroutines. The JVM specification has some confusing things to
72 // say about subroutines. For instance, it makes claims about not
73 // allowing subroutines to merge and it rejects recursive subroutines.
74 // For the most part these are red herrings; we used to try to follow
75 // these things but they lead to problems. For example, the notion of
76 // "being in a subroutine" is not well-defined: is an exception
77 // handler in a subroutine? If you never execute the `ret' but
78 // instead `goto 1' do you remain in the subroutine?
80 // For clarity on what is really required for type safety, read
81 // "Simple Verification Technique for Complex Java Bytecode
82 // Subroutines" by Alessandro Coglio. Among other things this paper
83 // shows that recursive subroutines are not harmful to type safety.
84 // We implement something similar to what he proposes. Note that this
85 // means that this verifier will accept code that is rejected by some
88 // For those not wanting to read the paper, the basic observation is
89 // that we can maintain split states in subroutines. We maintain one
90 // state for each calling `jsr'. In other words, we re-verify a
91 // subroutine once for each caller, using the exact types held by the
92 // callers (as opposed to the old approach of merging types and
93 // keeping a bitmap registering what did or did not change). This
94 // approach lets us continue to verify correctly even when a
95 // subroutine is exited via `goto' or `athrow' and not `ret'.
97 // In some other areas the JVM specification is (mildly) incorrect,
98 // but we still implement what is specified. For instance, you cannot
99 // violate type safety by allocating an object with `new' and then
100 // failing to initialize it, no matter how one branches or where one
101 // stores the uninitialized reference. See "Improving the official
102 // specification of Java bytecode verification" by Alessandro Coglio.
103 // Similarly, there's no real point in enforcing that padding bytes or
104 // the mystery byte of invokeinterface must be 0, but we do that too.
106 // The verifier is currently neither completely lazy nor eager when it
107 // comes to loading classes. It tries to represent types by name when
108 // possible, and then loads them when it needs to verify a fact about
109 // the type. Checking types by name is valid because we only use
110 // names which come from the current class' constant pool. Since all
111 // such names are looked up using the same class loader, there is no
112 // danger that we might be fooled into comparing different types with
115 // In the future we plan to allow for a completely lazy mode of
116 // operation, where the verifier will construct a list of type
117 // assertions to be checked later.
119 // Some test cases for the verifier live in the "verify" module of the
120 // Mauve test suite. However, some of these are presently
121 // (2004-01-20) believed to be incorrect. (More precisely the notion
122 // of "correct" is not well-defined, and this verifier differs from
123 // others while remaining type-safe.) Some other tests live in the
124 // libgcj test suite.
125 class _Jv_BytecodeVerifier
129 static const int FLAG_INSN_START = 1;
130 static const int FLAG_BRANCH_TARGET = 2;
135 struct ref_intersection;
146 // The PC corresponding to the start of the current instruction.
149 // The current state of the stack, locals, etc.
150 state *current_state;
152 // At each branch target we keep a linked list of all the states we
153 // can process at that point. We'll only have multiple states at a
154 // given PC if they both have different return-address types in the
155 // same stack or local slot. This array is indexed by PC and holds
156 // the list of all such states.
157 linked<state> **states;
159 // We keep a linked list of all the states which we must reverify.
160 // This is the head of the list.
161 state *next_verify_state;
163 // We keep some flags for each instruction. The values are the
164 // FLAG_* constants defined above. This is an array indexed by PC.
167 // The bytecode itself.
168 unsigned char *bytecode;
170 _Jv_InterpException *exception;
173 jclass current_class;
175 _Jv_InterpMethod *current_method;
177 // A linked list of utf8 objects we allocate. This is really ugly,
178 // but without this our utf8 objects would be collected.
179 linked<_Jv_Utf8Const> *utf8_list;
181 // A linked list of all ref_intersection objects we allocate.
182 ref_intersection *isect_list;
184 // Create a new Utf-8 constant and return it. We do this to avoid
185 // having our Utf-8 constants prematurely collected. FIXME this is
187 _Jv_Utf8Const *make_utf8_const (char *s, int len)
189 _Jv_Utf8Const *val = _Jv_makeUtf8Const (s, len);
190 _Jv_Utf8Const *r = (_Jv_Utf8Const *) _Jv_Malloc (sizeof (_Jv_Utf8Const)
193 r->length = val->length;
195 memcpy (r->data, val->data, val->length + 1);
197 linked<_Jv_Utf8Const> *lu
198 = (linked<_Jv_Utf8Const> *) _Jv_Malloc (sizeof (linked<_Jv_Utf8Const>));
200 lu->next = utf8_list;
206 __attribute__ ((__noreturn__)) void verify_fail (char *s, jint pc = -1)
208 using namespace java::lang;
209 StringBuffer *buf = new StringBuffer ();
211 buf->append (JvNewStringLatin1 ("verification failed"));
216 buf->append (JvNewStringLatin1 (" at PC "));
220 _Jv_InterpMethod *method = current_method;
221 buf->append (JvNewStringLatin1 (" in "));
222 buf->append (current_class->getName());
223 buf->append ((jchar) ':');
224 buf->append (JvNewStringUTF (method->get_method()->name->data));
225 buf->append ((jchar) '(');
226 buf->append (JvNewStringUTF (method->get_method()->signature->data));
227 buf->append ((jchar) ')');
229 buf->append (JvNewStringLatin1 (": "));
230 buf->append (JvNewStringLatin1 (s));
231 throw new java::lang::VerifyError (buf->toString ());
234 // This enum holds a list of tags for all the different types we
235 // need to handle. Reference types are treated specially by the
241 // The values for primitive types are chosen to correspond to values
242 // specified to newarray.
252 // Used when overwriting second word of a double or long in the
253 // local variables. Also used after merging local variable states
254 // to indicate an unusable value.
257 // This is the second word of a two-word value, i.e., a double or
261 // Everything after `reference_type' must be a reference type.
264 uninitialized_reference_type
267 // This represents a merged class type. Some verifiers (including
268 // earlier versions of this one) will compute the intersection of
269 // two class types when merging states. However, this loses
270 // critical information about interfaces implemented by the various
271 // classes. So instead we keep track of all the actual classes that
273 struct ref_intersection
275 // Whether or not this type has been resolved.
281 // For a resolved reference type, this is a pointer to the class.
283 // For other reference types, this it the name of the class.
287 // Link to the next reference in the intersection.
288 ref_intersection *ref_next;
290 // This is used to keep track of all the allocated
291 // ref_intersection objects, so we can free them.
292 // FIXME: we should allocate these in chunks.
293 ref_intersection *alloc_next;
295 ref_intersection (jclass klass, _Jv_BytecodeVerifier *verifier)
300 alloc_next = verifier->isect_list;
301 verifier->isect_list = this;
304 ref_intersection (_Jv_Utf8Const *name, _Jv_BytecodeVerifier *verifier)
309 alloc_next = verifier->isect_list;
310 verifier->isect_list = this;
313 ref_intersection (ref_intersection *dup, ref_intersection *tail,
314 _Jv_BytecodeVerifier *verifier)
317 is_resolved = dup->is_resolved;
319 alloc_next = verifier->isect_list;
320 verifier->isect_list = this;
323 bool equals (ref_intersection *other, _Jv_BytecodeVerifier *verifier)
325 if (! is_resolved && ! other->is_resolved
326 && _Jv_equalUtf8Consts (data.name, other->data.name))
330 if (! other->is_resolved)
331 other->resolve (verifier);
332 return data.klass == other->data.klass;
335 // Merge THIS type into OTHER, returning the result. This will
336 // return OTHER if all the classes in THIS already appear in
338 ref_intersection *merge (ref_intersection *other,
339 _Jv_BytecodeVerifier *verifier)
341 ref_intersection *tail = other;
342 for (ref_intersection *self = this; self != NULL; self = self->ref_next)
345 for (ref_intersection *iter = other; iter != NULL;
346 iter = iter->ref_next)
348 if (iter->equals (self, verifier))
356 tail = new ref_intersection (self, tail, verifier);
361 void resolve (_Jv_BytecodeVerifier *verifier)
366 using namespace java::lang;
367 java::lang::ClassLoader *loader
368 = verifier->current_class->getClassLoaderInternal();
369 // We might see either kind of name. Sigh.
370 if (data.name->data[0] == 'L'
371 && data.name->data[data.name->length - 1] == ';')
372 data.klass = _Jv_FindClassFromSignature (data.name->data, loader);
374 data.klass = Class::forName (_Jv_NewStringUtf8Const (data.name),
379 // See if an object of type OTHER can be assigned to an object of
380 // type *THIS. This might resolve classes in one chain or the
382 bool compatible (ref_intersection *other,
383 _Jv_BytecodeVerifier *verifier)
385 ref_intersection *self = this;
387 for (; self != NULL; self = self->ref_next)
389 ref_intersection *other_iter = other;
391 for (; other_iter != NULL; other_iter = other_iter->ref_next)
393 // Avoid resolving if possible.
394 if (! self->is_resolved
395 && ! other_iter->is_resolved
396 && _Jv_equalUtf8Consts (self->data.name,
397 other_iter->data.name))
400 if (! self->is_resolved)
401 self->resolve(verifier);
402 if (! other_iter->is_resolved)
403 other_iter->resolve(verifier);
405 if (! is_assignable_from_slow (self->data.klass,
406 other_iter->data.klass))
416 // assert (ref_next == NULL);
418 return data.klass->isArray ();
420 return data.name->data[0] == '[';
423 bool isinterface (_Jv_BytecodeVerifier *verifier)
425 // assert (ref_next == NULL);
428 return data.klass->isInterface ();
431 bool isabstract (_Jv_BytecodeVerifier *verifier)
433 // assert (ref_next == NULL);
436 using namespace java::lang::reflect;
437 return Modifier::isAbstract (data.klass->getModifiers ());
440 jclass getclass (_Jv_BytecodeVerifier *verifier)
447 int count_dimensions ()
452 jclass k = data.klass;
453 while (k->isArray ())
455 k = k->getComponentType ();
461 char *p = data.name->data;
468 void *operator new (size_t bytes)
470 return _Jv_Malloc (bytes);
473 void operator delete (void *mem)
479 // Return the type_val corresponding to a primitive signature
480 // character. For instance `I' returns `int.class'.
481 type_val get_type_val_for_signature (jchar sig)
514 verify_fail ("invalid signature");
519 // Return the type_val corresponding to a primitive class.
520 type_val get_type_val_for_signature (jclass k)
522 return get_type_val_for_signature ((jchar) k->method_count);
525 // This is like _Jv_IsAssignableFrom, but it works even if SOURCE or
526 // TARGET haven't been prepared.
527 static bool is_assignable_from_slow (jclass target, jclass source)
529 // First, strip arrays.
530 while (target->isArray ())
532 // If target is array, source must be as well.
533 if (! source->isArray ())
535 target = target->getComponentType ();
536 source = source->getComponentType ();
540 if (target == &java::lang::Object::class$)
545 if (source == target)
548 if (target->isPrimitive () || source->isPrimitive ())
551 if (target->isInterface ())
553 for (int i = 0; i < source->interface_count; ++i)
555 // We use a recursive call because we also need to
556 // check superinterfaces.
557 if (is_assignable_from_slow (target, source->interfaces[i]))
561 source = source->getSuperclass ();
563 while (source != NULL);
568 // The `type' class is used to represent a single type in the
575 // For reference types, the representation of the type.
576 ref_intersection *klass;
578 // This is used in two situations.
580 // First, when constructing a new object, it is the PC of the
581 // `new' instruction which created the object. We use the special
582 // value UNINIT to mean that this is uninitialized, and the
583 // special value SELF for the case where the current method is
584 // itself the <init> method.
586 // Second, when the key is return_address_type, this holds the PC
587 // of the instruction following the `jsr'.
590 static const int UNINIT = -2;
591 static const int SELF = -1;
593 // Basic constructor.
596 key = unsuitable_type;
601 // Make a new instance given the type tag. We assume a generic
602 // `reference_type' means Object.
606 // For reference_type, if KLASS==NULL then that means we are
607 // looking for a generic object of any kind, including an
608 // uninitialized reference.
613 // Make a new instance given a class.
614 type (jclass k, _Jv_BytecodeVerifier *verifier)
616 key = reference_type;
617 klass = new ref_intersection (k, verifier);
621 // Make a new instance given the name of a class.
622 type (_Jv_Utf8Const *n, _Jv_BytecodeVerifier *verifier)
624 key = reference_type;
625 klass = new ref_intersection (n, verifier);
637 // These operators are required because libgcj can't link in
639 void *operator new[] (size_t bytes)
641 return _Jv_Malloc (bytes);
644 void operator delete[] (void *mem)
649 type& operator= (type_val k)
657 type& operator= (const type& t)
665 // Promote a numeric type.
668 if (key == boolean_type || key == char_type
669 || key == byte_type || key == short_type)
674 // Mark this type as the uninitialized result of `new'.
675 void set_uninitialized (int npc, _Jv_BytecodeVerifier *verifier)
677 if (key == reference_type)
678 key = uninitialized_reference_type;
680 verifier->verify_fail ("internal error in type::uninitialized");
684 // Mark this type as now initialized.
685 void set_initialized (int npc)
687 if (npc != UNINIT && pc == npc && key == uninitialized_reference_type)
689 key = reference_type;
694 // Mark this type as a particular return address.
695 void set_return_address (int npc)
700 // Return true if this type and type OTHER are considered
701 // mergeable for the purposes of state merging. This is related
702 // to subroutine handling. For this purpose two types are
703 // considered unmergeable if they are both return-addresses but
704 // have different PCs.
705 bool state_mergeable_p (const type &other) const
707 return (key != return_address_type
708 || other.key != return_address_type
712 // Return true if an object of type K can be assigned to a variable
713 // of type *THIS. Handle various special cases too. Might modify
714 // *THIS or K. Note however that this does not perform numeric
716 bool compatible (type &k, _Jv_BytecodeVerifier *verifier)
718 // Any type is compatible with the unsuitable type.
719 if (key == unsuitable_type)
722 if (key < reference_type || k.key < reference_type)
725 // The `null' type is convertible to any initialized reference
727 if (key == null_type)
728 return k.key != uninitialized_reference_type;
729 if (k.key == null_type)
730 return key != uninitialized_reference_type;
732 // A special case for a generic reference.
736 verifier->verify_fail ("programmer error in type::compatible");
738 // An initialized type and an uninitialized type are not
740 if (isinitialized () != k.isinitialized ())
743 // Two uninitialized objects are compatible if either:
744 // * The PCs are identical, or
745 // * One PC is UNINIT.
746 if (! isinitialized ())
748 if (pc != k.pc && pc != UNINIT && k.pc != UNINIT)
752 return klass->compatible(k.klass, verifier);
757 return key == void_type;
762 return key == long_type || key == double_type;
765 // Return number of stack or local variable slots taken by this
769 return iswide () ? 2 : 1;
772 bool isarray () const
774 // We treat null_type as not an array. This is ok based on the
775 // current uses of this method.
776 if (key == reference_type)
777 return klass->isarray ();
783 return key == null_type;
786 bool isinterface (_Jv_BytecodeVerifier *verifier)
788 if (key != reference_type)
790 return klass->isinterface (verifier);
793 bool isabstract (_Jv_BytecodeVerifier *verifier)
795 if (key != reference_type)
797 return klass->isabstract (verifier);
800 // Return the element type of an array.
801 type element_type (_Jv_BytecodeVerifier *verifier)
803 if (key != reference_type)
804 verifier->verify_fail ("programmer error in type::element_type()", -1);
806 jclass k = klass->getclass (verifier)->getComponentType ();
807 if (k->isPrimitive ())
808 return type (verifier->get_type_val_for_signature (k));
809 return type (k, verifier);
812 // Return the array type corresponding to an initialized
813 // reference. We could expand this to work for other kinds of
814 // types, but currently we don't need to.
815 type to_array (_Jv_BytecodeVerifier *verifier)
817 if (key != reference_type)
818 verifier->verify_fail ("internal error in type::to_array()");
820 jclass k = klass->getclass (verifier);
821 return type (_Jv_GetArrayClass (k, k->getClassLoaderInternal()),
825 bool isreference () const
827 return key >= reference_type;
835 bool isinitialized () const
837 return key == reference_type || key == null_type;
840 bool isresolved () const
842 return (key == reference_type
844 || key == uninitialized_reference_type);
847 void verify_dimensions (int ndims, _Jv_BytecodeVerifier *verifier)
849 // The way this is written, we don't need to check isarray().
850 if (key != reference_type)
851 verifier->verify_fail ("internal error in verify_dimensions:"
852 " not a reference type");
854 if (klass->count_dimensions () < ndims)
855 verifier->verify_fail ("array type has fewer dimensions"
859 // Merge OLD_TYPE into this. On error throw exception. Return
860 // true if the merge caused a type change.
861 bool merge (type& old_type, bool local_semantics,
862 _Jv_BytecodeVerifier *verifier)
864 bool changed = false;
865 bool refo = old_type.isreference ();
866 bool refn = isreference ();
869 if (old_type.key == null_type)
871 else if (key == null_type)
876 else if (isinitialized () != old_type.isinitialized ())
877 verifier->verify_fail ("merging initialized and uninitialized types");
880 if (! isinitialized ())
884 else if (old_type.pc == UNINIT)
886 else if (pc != old_type.pc)
887 verifier->verify_fail ("merging different uninitialized types");
890 ref_intersection *merged = old_type.klass->merge (klass,
899 else if (refo || refn || key != old_type.key)
903 // If we already have an `unsuitable' type, then we
904 // don't need to change again.
905 if (key != unsuitable_type)
907 key = unsuitable_type;
912 verifier->verify_fail ("unmergeable type");
918 void print (void) const
923 case boolean_type: c = 'Z'; break;
924 case byte_type: c = 'B'; break;
925 case char_type: c = 'C'; break;
926 case short_type: c = 'S'; break;
927 case int_type: c = 'I'; break;
928 case long_type: c = 'J'; break;
929 case float_type: c = 'F'; break;
930 case double_type: c = 'D'; break;
931 case void_type: c = 'V'; break;
932 case unsuitable_type: c = '-'; break;
933 case return_address_type: c = 'r'; break;
934 case continuation_type: c = '+'; break;
935 case reference_type: c = 'L'; break;
936 case null_type: c = '@'; break;
937 case uninitialized_reference_type: c = 'U'; break;
939 debug_print ("%c", c);
941 #endif /* VERIFY_DEBUG */
944 // This class holds all the state information we need for a given
948 // The current top of the stack, in terms of slots.
950 // The current depth of the stack. This will be larger than
951 // STACKTOP when wide types are on the stack.
955 // The local variables.
957 // We keep track of the type of `this' specially. This is used to
958 // ensure that an instance initializer invokes another initializer
959 // on `this' before returning. We must keep track of this
960 // specially because otherwise we might be confused by code which
961 // assigns to locals[0] (overwriting `this') and then returns
962 // without really initializing.
965 // The PC for this state. This is only valid on states which are
966 // permanently attached to a given PC. For an object like
967 // `current_state', which is used transiently, this has no
970 // We keep a linked list of all states requiring reverification.
971 // If this is the special value INVALID_STATE then this state is
972 // not on the list. NULL marks the end of the linked list.
975 // NO_NEXT is the PC value meaning that a new state must be
976 // acquired from the verification list.
977 static const int NO_NEXT = -1;
984 next = INVALID_STATE;
987 state (int max_stack, int max_locals)
992 stack = new type[max_stack];
993 for (int i = 0; i < max_stack; ++i)
994 stack[i] = unsuitable_type;
995 locals = new type[max_locals];
996 for (int i = 0; i < max_locals; ++i)
997 locals[i] = unsuitable_type;
999 next = INVALID_STATE;
1002 state (const state *orig, int max_stack, int max_locals)
1004 stack = new type[max_stack];
1005 locals = new type[max_locals];
1006 copy (orig, max_stack, max_locals);
1008 next = INVALID_STATE;
1019 void *operator new[] (size_t bytes)
1021 return _Jv_Malloc (bytes);
1024 void operator delete[] (void *mem)
1029 void *operator new (size_t bytes)
1031 return _Jv_Malloc (bytes);
1034 void operator delete (void *mem)
1039 void copy (const state *copy, int max_stack, int max_locals)
1041 stacktop = copy->stacktop;
1042 stackdepth = copy->stackdepth;
1043 for (int i = 0; i < max_stack; ++i)
1044 stack[i] = copy->stack[i];
1045 for (int i = 0; i < max_locals; ++i)
1046 locals[i] = copy->locals[i];
1048 this_type = copy->this_type;
1049 // Don't modify `next' or `pc'.
1052 // Modify this state to reflect entry to an exception handler.
1053 void set_exception (type t, int max_stack)
1058 for (int i = stacktop; i < max_stack; ++i)
1059 stack[i] = unsuitable_type;
1062 inline int get_pc () const
1067 void set_pc (int npc)
1072 // Merge STATE_OLD into this state. Destructively modifies this
1073 // state. Returns true if the new state was in fact changed.
1074 // Will throw an exception if the states are not mergeable.
1075 bool merge (state *state_old, int max_locals,
1076 _Jv_BytecodeVerifier *verifier)
1078 bool changed = false;
1080 // Special handling for `this'. If one or the other is
1081 // uninitialized, then the merge is uninitialized.
1082 if (this_type.isinitialized ())
1083 this_type = state_old->this_type;
1086 if (state_old->stacktop != stacktop) // FIXME stackdepth instead?
1087 verifier->verify_fail ("stack sizes differ");
1088 for (int i = 0; i < state_old->stacktop; ++i)
1090 if (stack[i].merge (state_old->stack[i], false, verifier))
1094 // Merge local variables.
1095 for (int i = 0; i < max_locals; ++i)
1097 if (locals[i].merge (state_old->locals[i], true, verifier))
1104 // Throw an exception if there is an uninitialized object on the
1105 // stack or in a local variable. EXCEPTION_SEMANTICS controls
1106 // whether we're using backwards-branch or exception-handing
1108 void check_no_uninitialized_objects (int max_locals,
1109 _Jv_BytecodeVerifier *verifier,
1110 bool exception_semantics = false)
1112 if (! exception_semantics)
1114 for (int i = 0; i < stacktop; ++i)
1115 if (stack[i].isreference () && ! stack[i].isinitialized ())
1116 verifier->verify_fail ("uninitialized object on stack");
1119 for (int i = 0; i < max_locals; ++i)
1120 if (locals[i].isreference () && ! locals[i].isinitialized ())
1121 verifier->verify_fail ("uninitialized object in local variable");
1123 check_this_initialized (verifier);
1126 // Ensure that `this' has been initialized.
1127 void check_this_initialized (_Jv_BytecodeVerifier *verifier)
1129 if (this_type.isreference () && ! this_type.isinitialized ())
1130 verifier->verify_fail ("`this' is uninitialized");
1133 // Set type of `this'.
1134 void set_this_type (const type &k)
1139 // Mark each `new'd object we know of that was allocated at PC as
1141 void set_initialized (int pc, int max_locals)
1143 for (int i = 0; i < stacktop; ++i)
1144 stack[i].set_initialized (pc);
1145 for (int i = 0; i < max_locals; ++i)
1146 locals[i].set_initialized (pc);
1147 this_type.set_initialized (pc);
1150 // This tests to see whether two states can be considered "merge
1151 // compatible". If both states have a return-address in the same
1152 // slot, and the return addresses are different, then they are not
1153 // compatible and we must not try to merge them.
1154 bool state_mergeable_p (state *other, int max_locals,
1155 _Jv_BytecodeVerifier *verifier)
1157 // This is tricky: if the stack sizes differ, then not only are
1158 // these not mergeable, but in fact we should give an error, as
1159 // we've found two execution paths that reach a branch target
1160 // with different stack depths. FIXME stackdepth instead?
1161 if (stacktop != other->stacktop)
1162 verifier->verify_fail ("stack sizes differ");
1164 for (int i = 0; i < stacktop; ++i)
1165 if (! stack[i].state_mergeable_p (other->stack[i]))
1167 for (int i = 0; i < max_locals; ++i)
1168 if (! locals[i].state_mergeable_p (other->locals[i]))
1173 void reverify (_Jv_BytecodeVerifier *verifier)
1175 if (next == INVALID_STATE)
1177 next = verifier->next_verify_state;
1178 verifier->next_verify_state = this;
1183 void print (const char *leader, int pc,
1184 int max_stack, int max_locals) const
1186 debug_print ("%s [%4d]: [stack] ", leader, pc);
1188 for (i = 0; i < stacktop; ++i)
1190 for (; i < max_stack; ++i)
1192 debug_print (" [local] ");
1193 for (i = 0; i < max_locals; ++i)
1195 debug_print (" | %p\n", this);
1198 inline void print (const char *, int, int, int) const
1201 #endif /* VERIFY_DEBUG */
1206 if (current_state->stacktop <= 0)
1207 verify_fail ("stack empty");
1208 type r = current_state->stack[--current_state->stacktop];
1209 current_state->stackdepth -= r.depth ();
1210 if (current_state->stackdepth < 0)
1211 verify_fail ("stack empty", start_PC);
1217 type r = pop_raw ();
1219 verify_fail ("narrow pop of wide type");
1223 type pop_type (type match)
1226 type t = pop_raw ();
1227 if (! match.compatible (t, this))
1228 verify_fail ("incompatible type on stack");
1232 // Pop a reference which is guaranteed to be initialized. MATCH
1233 // doesn't have to be a reference type; in this case this acts like
1235 type pop_init_ref (type match)
1237 type t = pop_raw ();
1238 if (t.isreference () && ! t.isinitialized ())
1239 verify_fail ("initialized reference required");
1240 else if (! match.compatible (t, this))
1241 verify_fail ("incompatible type on stack");
1245 // Pop a reference type or a return address.
1246 type pop_ref_or_return ()
1248 type t = pop_raw ();
1249 if (! t.isreference () && t.key != return_address_type)
1250 verify_fail ("expected reference or return address on stack");
1254 void push_type (type t)
1256 // If T is a numeric type like short, promote it to int.
1259 int depth = t.depth ();
1260 if (current_state->stackdepth + depth > current_method->max_stack)
1261 verify_fail ("stack overflow");
1262 current_state->stack[current_state->stacktop++] = t;
1263 current_state->stackdepth += depth;
1266 void set_variable (int index, type t)
1268 // If T is a numeric type like short, promote it to int.
1271 int depth = t.depth ();
1272 if (index > current_method->max_locals - depth)
1273 verify_fail ("invalid local variable");
1274 current_state->locals[index] = t;
1277 current_state->locals[index + 1] = continuation_type;
1278 if (index > 0 && current_state->locals[index - 1].iswide ())
1279 current_state->locals[index - 1] = unsuitable_type;
1282 type get_variable (int index, type t)
1284 int depth = t.depth ();
1285 if (index > current_method->max_locals - depth)
1286 verify_fail ("invalid local variable");
1287 if (! t.compatible (current_state->locals[index], this))
1288 verify_fail ("incompatible type in local variable");
1291 type t (continuation_type);
1292 if (! current_state->locals[index + 1].compatible (t, this))
1293 verify_fail ("invalid local variable");
1295 return current_state->locals[index];
1298 // Make sure ARRAY is an array type and that its elements are
1299 // compatible with type ELEMENT. Returns the actual element type.
1300 type require_array_type (type array, type element)
1302 // An odd case. Here we just pretend that everything went ok. If
1303 // the requested element type is some kind of reference, return
1304 // the null type instead.
1305 if (array.isnull ())
1306 return element.isreference () ? type (null_type) : element;
1308 if (! array.isarray ())
1309 verify_fail ("array required");
1311 type t = array.element_type (this);
1312 if (! element.compatible (t, this))
1314 // Special case for byte arrays, which must also be boolean
1317 if (element.key == byte_type)
1319 type e2 (boolean_type);
1320 ok = e2.compatible (t, this);
1323 verify_fail ("incompatible array element type");
1326 // Return T and not ELEMENT, because T might be specialized.
1332 if (PC >= current_method->code_length)
1333 verify_fail ("premature end of bytecode");
1334 return (jint) bytecode[PC++] & 0xff;
1339 jint b1 = get_byte ();
1340 jint b2 = get_byte ();
1341 return (jint) ((b1 << 8) | b2) & 0xffff;
1346 jint b1 = get_byte ();
1347 jint b2 = get_byte ();
1348 jshort s = (b1 << 8) | b2;
1354 jint b1 = get_byte ();
1355 jint b2 = get_byte ();
1356 jint b3 = get_byte ();
1357 jint b4 = get_byte ();
1358 return (b1 << 24) | (b2 << 16) | (b3 << 8) | b4;
1361 int compute_jump (int offset)
1363 int npc = start_PC + offset;
1364 if (npc < 0 || npc >= current_method->code_length)
1365 verify_fail ("branch out of range", start_PC);
1369 // Add a new state to the state list at NPC.
1370 state *add_new_state (int npc, state *old_state)
1372 state *new_state = new state (old_state, current_method->max_stack,
1373 current_method->max_locals);
1374 debug_print ("== New state in add_new_state\n");
1375 new_state->print ("New", npc, current_method->max_stack,
1376 current_method->max_locals);
1377 linked<state> *nlink
1378 = (linked<state> *) _Jv_Malloc (sizeof (linked<state>));
1379 nlink->val = new_state;
1380 nlink->next = states[npc];
1381 states[npc] = nlink;
1382 new_state->set_pc (npc);
1386 // Merge the indicated state into the state at the branch target and
1387 // schedule a new PC if there is a change. NPC is the PC of the
1388 // branch target, and FROM_STATE is the state at the source of the
1389 // branch. This method returns true if the destination state
1390 // changed and requires reverification, false otherwise.
1391 void merge_into (int npc, state *from_state)
1393 // Iterate over all target states and merge our state into each,
1394 // if applicable. FIXME one improvement we could make here is
1395 // "state destruction". Merging a new state into an existing one
1396 // might cause a return_address_type to be merged to
1397 // unsuitable_type. In this case the resulting state may now be
1398 // mergeable with other states currently held in parallel at this
1399 // location. So in this situation we could pairwise compare and
1400 // reduce the number of parallel states.
1401 bool applicable = false;
1402 for (linked<state> *iter = states[npc]; iter != NULL; iter = iter->next)
1404 state *new_state = iter->val;
1405 if (new_state->state_mergeable_p (from_state,
1406 current_method->max_locals, this))
1410 debug_print ("== Merge states in merge_into\n");
1411 from_state->print ("Frm", start_PC, current_method->max_stack,
1412 current_method->max_locals);
1413 new_state->print (" To", npc, current_method->max_stack,
1414 current_method->max_locals);
1415 bool changed = new_state->merge (from_state,
1416 current_method->max_locals,
1418 new_state->print ("New", npc, current_method->max_stack,
1419 current_method->max_locals);
1422 new_state->reverify (this);
1428 // Either we don't yet have a state at NPC, or we have a
1429 // return-address type that is in conflict with all existing
1430 // state. So, we need to create a new entry.
1431 state *new_state = add_new_state (npc, from_state);
1432 // A new state added in this way must always be reverified.
1433 new_state->reverify (this);
1437 void push_jump (int offset)
1439 int npc = compute_jump (offset);
1441 current_state->check_no_uninitialized_objects (current_method->max_locals, this);
1442 merge_into (npc, current_state);
1445 void push_exception_jump (type t, int pc)
1447 current_state->check_no_uninitialized_objects (current_method->max_locals,
1449 state s (current_state, current_method->max_stack,
1450 current_method->max_locals);
1451 if (current_method->max_stack < 1)
1452 verify_fail ("stack overflow at exception handler");
1453 s.set_exception (t, current_method->max_stack);
1454 merge_into (pc, &s);
1459 state *new_state = next_verify_state;
1460 if (new_state == INVALID_STATE)
1461 verify_fail ("programmer error in pop_jump");
1462 if (new_state != NULL)
1464 next_verify_state = new_state->next;
1465 new_state->next = INVALID_STATE;
1470 void invalidate_pc ()
1472 PC = state::NO_NEXT;
1475 void note_branch_target (int pc)
1477 // Don't check `pc <= PC', because we've advanced PC after
1478 // fetching the target and we haven't yet checked the next
1480 if (pc < PC && ! (flags[pc] & FLAG_INSN_START))
1481 verify_fail ("branch not to instruction start", start_PC);
1482 flags[pc] |= FLAG_BRANCH_TARGET;
1485 void skip_padding ()
1487 while ((PC % 4) > 0)
1488 if (get_byte () != 0)
1489 verify_fail ("found nonzero padding byte");
1492 // Do the work for a `ret' instruction. INDEX is the index into the
1494 void handle_ret_insn (int index)
1496 type ret_addr = get_variable (index, return_address_type);
1497 // It would be nice if we could do this. However, the JVM Spec
1498 // doesn't say that this is what happens. It is implied that
1499 // reusing a return address is invalid, but there's no actual
1500 // prohibition against it.
1501 // set_variable (index, unsuitable_type);
1503 int npc = ret_addr.get_pc ();
1504 // We might be returning to a `jsr' that is at the end of the
1505 // bytecode. This is ok if we never return from the called
1506 // subroutine, but if we see this here it is an error.
1507 if (npc >= current_method->code_length)
1508 verify_fail ("fell off end");
1511 current_state->check_no_uninitialized_objects (current_method->max_locals,
1513 merge_into (npc, current_state);
1517 void handle_jsr_insn (int offset)
1519 int npc = compute_jump (offset);
1522 current_state->check_no_uninitialized_objects (current_method->max_locals, this);
1524 // Modify our state as appropriate for entry into a subroutine.
1525 type ret_addr (return_address_type);
1526 ret_addr.set_return_address (PC);
1527 push_type (ret_addr);
1528 merge_into (npc, current_state);
1532 jclass construct_primitive_array_type (type_val prim)
1538 k = JvPrimClass (boolean);
1541 k = JvPrimClass (char);
1544 k = JvPrimClass (float);
1547 k = JvPrimClass (double);
1550 k = JvPrimClass (byte);
1553 k = JvPrimClass (short);
1556 k = JvPrimClass (int);
1559 k = JvPrimClass (long);
1562 // These aren't used here but we call them out to avoid
1565 case unsuitable_type:
1566 case return_address_type:
1567 case continuation_type:
1568 case reference_type:
1570 case uninitialized_reference_type:
1572 verify_fail ("unknown type in construct_primitive_array_type");
1574 k = _Jv_GetArrayClass (k, NULL);
1578 // This pass computes the location of branch targets and also
1579 // instruction starts.
1580 void branch_prepass ()
1582 flags = (char *) _Jv_Malloc (current_method->code_length);
1584 for (int i = 0; i < current_method->code_length; ++i)
1588 while (PC < current_method->code_length)
1590 // Set `start_PC' early so that error checking can have the
1593 flags[PC] |= FLAG_INSN_START;
1595 java_opcode opcode = (java_opcode) bytecode[PC++];
1599 case op_aconst_null:
1735 case op_monitorenter:
1736 case op_monitorexit:
1744 case op_arraylength:
1776 case op_invokespecial:
1777 case op_invokestatic:
1778 case op_invokevirtual:
1782 case op_multianewarray:
1805 note_branch_target (compute_jump (get_short ()));
1808 case op_tableswitch:
1811 note_branch_target (compute_jump (get_int ()));
1812 jint low = get_int ();
1813 jint hi = get_int ();
1815 verify_fail ("invalid tableswitch", start_PC);
1816 for (int i = low; i <= hi; ++i)
1817 note_branch_target (compute_jump (get_int ()));
1821 case op_lookupswitch:
1824 note_branch_target (compute_jump (get_int ()));
1825 int npairs = get_int ();
1827 verify_fail ("too few pairs in lookupswitch", start_PC);
1828 while (npairs-- > 0)
1831 note_branch_target (compute_jump (get_int ()));
1836 case op_invokeinterface:
1844 opcode = (java_opcode) get_byte ();
1846 if (opcode == op_iinc)
1853 note_branch_target (compute_jump (get_int ()));
1856 // These are unused here, but we call them out explicitly
1857 // so that -Wswitch-enum doesn't complain.
1863 case op_putstatic_1:
1864 case op_putstatic_2:
1865 case op_putstatic_4:
1866 case op_putstatic_8:
1867 case op_putstatic_a:
1869 case op_getfield_2s:
1870 case op_getfield_2u:
1874 case op_getstatic_1:
1875 case op_getstatic_2s:
1876 case op_getstatic_2u:
1877 case op_getstatic_4:
1878 case op_getstatic_8:
1879 case op_getstatic_a:
1881 verify_fail ("unrecognized instruction in branch_prepass",
1885 // See if any previous branch tried to branch to the middle of
1886 // this instruction.
1887 for (int pc = start_PC + 1; pc < PC; ++pc)
1889 if ((flags[pc] & FLAG_BRANCH_TARGET))
1890 verify_fail ("branch to middle of instruction", pc);
1894 // Verify exception handlers.
1895 for (int i = 0; i < current_method->exc_count; ++i)
1897 if (! (flags[exception[i].handler_pc.i] & FLAG_INSN_START))
1898 verify_fail ("exception handler not at instruction start",
1899 exception[i].handler_pc.i);
1900 if (! (flags[exception[i].start_pc.i] & FLAG_INSN_START))
1901 verify_fail ("exception start not at instruction start",
1902 exception[i].start_pc.i);
1903 if (exception[i].end_pc.i != current_method->code_length
1904 && ! (flags[exception[i].end_pc.i] & FLAG_INSN_START))
1905 verify_fail ("exception end not at instruction start",
1906 exception[i].end_pc.i);
1908 flags[exception[i].handler_pc.i] |= FLAG_BRANCH_TARGET;
1912 void check_pool_index (int index)
1914 if (index < 0 || index >= current_class->constants.size)
1915 verify_fail ("constant pool index out of range", start_PC);
1918 type check_class_constant (int index)
1920 check_pool_index (index);
1921 _Jv_Constants *pool = ¤t_class->constants;
1922 if (pool->tags[index] == JV_CONSTANT_ResolvedClass)
1923 return type (pool->data[index].clazz, this);
1924 else if (pool->tags[index] == JV_CONSTANT_Class)
1925 return type (pool->data[index].utf8, this);
1926 verify_fail ("expected class constant", start_PC);
1929 type check_constant (int index)
1931 check_pool_index (index);
1932 _Jv_Constants *pool = ¤t_class->constants;
1933 if (pool->tags[index] == JV_CONSTANT_ResolvedString
1934 || pool->tags[index] == JV_CONSTANT_String)
1935 return type (&java::lang::String::class$, this);
1936 else if (pool->tags[index] == JV_CONSTANT_Integer)
1937 return type (int_type);
1938 else if (pool->tags[index] == JV_CONSTANT_Float)
1939 return type (float_type);
1940 verify_fail ("String, int, or float constant expected", start_PC);
1943 type check_wide_constant (int index)
1945 check_pool_index (index);
1946 _Jv_Constants *pool = ¤t_class->constants;
1947 if (pool->tags[index] == JV_CONSTANT_Long)
1948 return type (long_type);
1949 else if (pool->tags[index] == JV_CONSTANT_Double)
1950 return type (double_type);
1951 verify_fail ("long or double constant expected", start_PC);
1954 // Helper for both field and method. These are laid out the same in
1955 // the constant pool.
1956 type handle_field_or_method (int index, int expected,
1957 _Jv_Utf8Const **name,
1958 _Jv_Utf8Const **fmtype)
1960 check_pool_index (index);
1961 _Jv_Constants *pool = ¤t_class->constants;
1962 if (pool->tags[index] != expected)
1963 verify_fail ("didn't see expected constant", start_PC);
1964 // Once we know we have a Fieldref or Methodref we assume that it
1965 // is correctly laid out in the constant pool. I think the code
1966 // in defineclass.cc guarantees this.
1967 _Jv_ushort class_index, name_and_type_index;
1968 _Jv_loadIndexes (&pool->data[index],
1970 name_and_type_index);
1971 _Jv_ushort name_index, desc_index;
1972 _Jv_loadIndexes (&pool->data[name_and_type_index],
1973 name_index, desc_index);
1975 *name = pool->data[name_index].utf8;
1976 *fmtype = pool->data[desc_index].utf8;
1978 return check_class_constant (class_index);
1981 // Return field's type, compute class' type if requested.
1982 type check_field_constant (int index, type *class_type = NULL)
1984 _Jv_Utf8Const *name, *field_type;
1985 type ct = handle_field_or_method (index,
1986 JV_CONSTANT_Fieldref,
1987 &name, &field_type);
1990 if (field_type->data[0] == '[' || field_type->data[0] == 'L')
1991 return type (field_type, this);
1992 return get_type_val_for_signature (field_type->data[0]);
1995 type check_method_constant (int index, bool is_interface,
1996 _Jv_Utf8Const **method_name,
1997 _Jv_Utf8Const **method_signature)
1999 return handle_field_or_method (index,
2001 ? JV_CONSTANT_InterfaceMethodref
2002 : JV_CONSTANT_Methodref),
2003 method_name, method_signature);
2006 type get_one_type (char *&p)
2024 _Jv_Utf8Const *name = make_utf8_const (start, p - start);
2025 return type (name, this);
2028 // Casting to jchar here is ok since we are looking at an ASCII
2030 type_val rt = get_type_val_for_signature (jchar (v));
2032 if (arraycount == 0)
2034 // Callers of this function eventually push their arguments on
2035 // the stack. So, promote them here.
2036 return type (rt).promote ();
2039 jclass k = construct_primitive_array_type (rt);
2040 while (--arraycount > 0)
2041 k = _Jv_GetArrayClass (k, NULL);
2042 return type (k, this);
2045 void compute_argument_types (_Jv_Utf8Const *signature,
2048 char *p = signature->data;
2054 types[i++] = get_one_type (p);
2057 type compute_return_type (_Jv_Utf8Const *signature)
2059 char *p = signature->data;
2063 return get_one_type (p);
2066 void check_return_type (type onstack)
2068 type rt = compute_return_type (current_method->self->signature);
2069 if (! rt.compatible (onstack, this))
2070 verify_fail ("incompatible return type");
2073 // Initialize the stack for the new method. Returns true if this
2074 // method is an instance initializer.
2075 bool initialize_stack ()
2078 bool is_init = _Jv_equalUtf8Consts (current_method->self->name,
2080 bool is_clinit = _Jv_equalUtf8Consts (current_method->self->name,
2083 using namespace java::lang::reflect;
2084 if (! Modifier::isStatic (current_method->self->accflags))
2086 type kurr (current_class, this);
2089 kurr.set_uninitialized (type::SELF, this);
2093 verify_fail ("<clinit> method must be static");
2094 set_variable (0, kurr);
2095 current_state->set_this_type (kurr);
2101 verify_fail ("<init> method must be non-static");
2104 // We have to handle wide arguments specially here.
2105 int arg_count = _Jv_count_arguments (current_method->self->signature);
2106 type arg_types[arg_count];
2107 compute_argument_types (current_method->self->signature, arg_types);
2108 for (int i = 0; i < arg_count; ++i)
2110 set_variable (var, arg_types[i]);
2112 if (arg_types[i].iswide ())
2119 void verify_instructions_0 ()
2121 current_state = new state (current_method->max_stack,
2122 current_method->max_locals);
2127 // True if we are verifying an instance initializer.
2128 bool this_is_init = initialize_stack ();
2130 states = (linked<state> **) _Jv_Malloc (sizeof (linked<state> *)
2131 * current_method->code_length);
2132 for (int i = 0; i < current_method->code_length; ++i)
2135 next_verify_state = NULL;
2139 // If the PC was invalidated, get a new one from the work list.
2140 if (PC == state::NO_NEXT)
2142 state *new_state = pop_jump ();
2143 // If it is null, we're done.
2144 if (new_state == NULL)
2147 PC = new_state->get_pc ();
2148 debug_print ("== State pop from pending list\n");
2149 // Set up the current state.
2150 current_state->copy (new_state, current_method->max_stack,
2151 current_method->max_locals);
2155 // We only have to do this checking in the situation where
2156 // control flow falls through from the previous
2157 // instruction. Otherwise merging is done at the time we
2159 if (states[PC] != NULL)
2161 // We've already visited this instruction. So merge
2162 // the states together. It is simplest, but not most
2163 // efficient, to just always invalidate the PC here.
2164 merge_into (PC, current_state);
2170 // Control can't fall off the end of the bytecode. We need to
2171 // check this in both cases, not just the fall-through case,
2172 // because we don't check to see whether a `jsr' appears at
2173 // the end of the bytecode until we process a `ret'.
2174 if (PC >= current_method->code_length)
2175 verify_fail ("fell off end");
2177 // We only have to keep saved state at branch targets. If
2178 // we're at a branch target and the state here hasn't been set
2179 // yet, we set it now. You might notice that `ret' targets
2180 // won't necessarily have FLAG_BRANCH_TARGET set. This
2181 // doesn't matter, since those states will be filled in by
2183 if (states[PC] == NULL && (flags[PC] & FLAG_BRANCH_TARGET))
2184 add_new_state (PC, current_state);
2186 // Set this before handling exceptions so that debug output is
2190 // Update states for all active exception handlers. Ordinarily
2191 // there are not many exception handlers. So we simply run
2192 // through them all.
2193 for (int i = 0; i < current_method->exc_count; ++i)
2195 if (PC >= exception[i].start_pc.i && PC < exception[i].end_pc.i)
2197 type handler (&java::lang::Throwable::class$, this);
2198 if (exception[i].handler_type.i != 0)
2199 handler = check_class_constant (exception[i].handler_type.i);
2200 push_exception_jump (handler, exception[i].handler_pc.i);
2204 current_state->print (" ", PC, current_method->max_stack,
2205 current_method->max_locals);
2206 java_opcode opcode = (java_opcode) bytecode[PC++];
2212 case op_aconst_null:
2213 push_type (null_type);
2223 push_type (int_type);
2228 push_type (long_type);
2234 push_type (float_type);
2239 push_type (double_type);
2244 push_type (int_type);
2249 push_type (int_type);
2253 push_type (check_constant (get_byte ()));
2256 push_type (check_constant (get_ushort ()));
2259 push_type (check_wide_constant (get_ushort ()));
2263 push_type (get_variable (get_byte (), int_type));
2266 push_type (get_variable (get_byte (), long_type));
2269 push_type (get_variable (get_byte (), float_type));
2272 push_type (get_variable (get_byte (), double_type));
2275 push_type (get_variable (get_byte (), reference_type));
2282 push_type (get_variable (opcode - op_iload_0, int_type));
2288 push_type (get_variable (opcode - op_lload_0, long_type));
2294 push_type (get_variable (opcode - op_fload_0, float_type));
2300 push_type (get_variable (opcode - op_dload_0, double_type));
2306 push_type (get_variable (opcode - op_aload_0, reference_type));
2309 pop_type (int_type);
2310 push_type (require_array_type (pop_init_ref (reference_type),
2314 pop_type (int_type);
2315 push_type (require_array_type (pop_init_ref (reference_type),
2319 pop_type (int_type);
2320 push_type (require_array_type (pop_init_ref (reference_type),
2324 pop_type (int_type);
2325 push_type (require_array_type (pop_init_ref (reference_type),
2329 pop_type (int_type);
2330 push_type (require_array_type (pop_init_ref (reference_type),
2334 pop_type (int_type);
2335 require_array_type (pop_init_ref (reference_type), byte_type);
2336 push_type (int_type);
2339 pop_type (int_type);
2340 require_array_type (pop_init_ref (reference_type), char_type);
2341 push_type (int_type);
2344 pop_type (int_type);
2345 require_array_type (pop_init_ref (reference_type), short_type);
2346 push_type (int_type);
2349 set_variable (get_byte (), pop_type (int_type));
2352 set_variable (get_byte (), pop_type (long_type));
2355 set_variable (get_byte (), pop_type (float_type));
2358 set_variable (get_byte (), pop_type (double_type));
2361 set_variable (get_byte (), pop_ref_or_return ());
2367 set_variable (opcode - op_istore_0, pop_type (int_type));
2373 set_variable (opcode - op_lstore_0, pop_type (long_type));
2379 set_variable (opcode - op_fstore_0, pop_type (float_type));
2385 set_variable (opcode - op_dstore_0, pop_type (double_type));
2391 set_variable (opcode - op_astore_0, pop_ref_or_return ());
2394 pop_type (int_type);
2395 pop_type (int_type);
2396 require_array_type (pop_init_ref (reference_type), int_type);
2399 pop_type (long_type);
2400 pop_type (int_type);
2401 require_array_type (pop_init_ref (reference_type), long_type);
2404 pop_type (float_type);
2405 pop_type (int_type);
2406 require_array_type (pop_init_ref (reference_type), float_type);
2409 pop_type (double_type);
2410 pop_type (int_type);
2411 require_array_type (pop_init_ref (reference_type), double_type);
2414 pop_type (reference_type);
2415 pop_type (int_type);
2416 require_array_type (pop_init_ref (reference_type), reference_type);
2419 pop_type (int_type);
2420 pop_type (int_type);
2421 require_array_type (pop_init_ref (reference_type), byte_type);
2424 pop_type (int_type);
2425 pop_type (int_type);
2426 require_array_type (pop_init_ref (reference_type), char_type);
2429 pop_type (int_type);
2430 pop_type (int_type);
2431 require_array_type (pop_init_ref (reference_type), short_type);
2438 type t = pop_raw ();
2462 type t2 = pop_raw ();
2477 type t = pop_raw ();
2492 type t1 = pop_raw ();
2509 type t1 = pop_raw ();
2512 type t2 = pop_raw ();
2530 type t3 = pop_raw ();
2568 pop_type (int_type);
2569 push_type (pop_type (int_type));
2579 pop_type (long_type);
2580 push_type (pop_type (long_type));
2585 pop_type (int_type);
2586 push_type (pop_type (long_type));
2593 pop_type (float_type);
2594 push_type (pop_type (float_type));
2601 pop_type (double_type);
2602 push_type (pop_type (double_type));
2608 push_type (pop_type (int_type));
2611 push_type (pop_type (long_type));
2614 push_type (pop_type (float_type));
2617 push_type (pop_type (double_type));
2620 get_variable (get_byte (), int_type);
2624 pop_type (int_type);
2625 push_type (long_type);
2628 pop_type (int_type);
2629 push_type (float_type);
2632 pop_type (int_type);
2633 push_type (double_type);
2636 pop_type (long_type);
2637 push_type (int_type);
2640 pop_type (long_type);
2641 push_type (float_type);
2644 pop_type (long_type);
2645 push_type (double_type);
2648 pop_type (float_type);
2649 push_type (int_type);
2652 pop_type (float_type);
2653 push_type (long_type);
2656 pop_type (float_type);
2657 push_type (double_type);
2660 pop_type (double_type);
2661 push_type (int_type);
2664 pop_type (double_type);
2665 push_type (long_type);
2668 pop_type (double_type);
2669 push_type (float_type);
2672 pop_type (long_type);
2673 pop_type (long_type);
2674 push_type (int_type);
2678 pop_type (float_type);
2679 pop_type (float_type);
2680 push_type (int_type);
2684 pop_type (double_type);
2685 pop_type (double_type);
2686 push_type (int_type);
2694 pop_type (int_type);
2695 push_jump (get_short ());
2703 pop_type (int_type);
2704 pop_type (int_type);
2705 push_jump (get_short ());
2709 pop_type (reference_type);
2710 pop_type (reference_type);
2711 push_jump (get_short ());
2714 push_jump (get_short ());
2718 handle_jsr_insn (get_short ());
2721 handle_ret_insn (get_byte ());
2723 case op_tableswitch:
2725 pop_type (int_type);
2727 push_jump (get_int ());
2728 jint low = get_int ();
2729 jint high = get_int ();
2730 // Already checked LOW -vs- HIGH.
2731 for (int i = low; i <= high; ++i)
2732 push_jump (get_int ());
2737 case op_lookupswitch:
2739 pop_type (int_type);
2741 push_jump (get_int ());
2742 jint npairs = get_int ();
2743 // Already checked NPAIRS >= 0.
2745 for (int i = 0; i < npairs; ++i)
2747 jint key = get_int ();
2748 if (i > 0 && key <= lastkey)
2749 verify_fail ("lookupswitch pairs unsorted", start_PC);
2751 push_jump (get_int ());
2757 check_return_type (pop_type (int_type));
2761 check_return_type (pop_type (long_type));
2765 check_return_type (pop_type (float_type));
2769 check_return_type (pop_type (double_type));
2773 check_return_type (pop_init_ref (reference_type));
2777 // We only need to check this when the return type is
2778 // void, because all instance initializers return void.
2780 current_state->check_this_initialized (this);
2781 check_return_type (void_type);
2785 push_type (check_field_constant (get_ushort ()));
2788 pop_type (check_field_constant (get_ushort ()));
2793 type field = check_field_constant (get_ushort (), &klass);
2801 type field = check_field_constant (get_ushort (), &klass);
2804 // We have an obscure special case here: we can use
2805 // `putfield' on a field declared in this class, even if
2806 // `this' has not yet been initialized.
2807 if (! current_state->this_type.isinitialized ()
2808 && current_state->this_type.pc == type::SELF)
2809 klass.set_uninitialized (type::SELF, this);
2814 case op_invokevirtual:
2815 case op_invokespecial:
2816 case op_invokestatic:
2817 case op_invokeinterface:
2819 _Jv_Utf8Const *method_name, *method_signature;
2821 = check_method_constant (get_ushort (),
2822 opcode == op_invokeinterface,
2825 // NARGS is only used when we're processing
2826 // invokeinterface. It is simplest for us to compute it
2827 // here and then verify it later.
2829 if (opcode == op_invokeinterface)
2831 nargs = get_byte ();
2832 if (get_byte () != 0)
2833 verify_fail ("invokeinterface dummy byte is wrong");
2836 bool is_init = false;
2837 if (_Jv_equalUtf8Consts (method_name, gcj::init_name))
2840 if (opcode != op_invokespecial)
2841 verify_fail ("can't invoke <init>");
2843 else if (method_name->data[0] == '<')
2844 verify_fail ("can't invoke method starting with `<'");
2846 // Pop arguments and check types.
2847 int arg_count = _Jv_count_arguments (method_signature);
2848 type arg_types[arg_count];
2849 compute_argument_types (method_signature, arg_types);
2850 for (int i = arg_count - 1; i >= 0; --i)
2852 // This is only used for verifying the byte for
2854 nargs -= arg_types[i].depth ();
2855 pop_init_ref (arg_types[i]);
2858 if (opcode == op_invokeinterface
2860 verify_fail ("wrong argument count for invokeinterface");
2862 if (opcode != op_invokestatic)
2864 type t = class_type;
2867 // In this case the PC doesn't matter.
2868 t.set_uninitialized (type::UNINIT, this);
2869 // FIXME: check to make sure that the <init>
2870 // call is to the right class.
2871 // It must either be super or an exact class
2874 type raw = pop_raw ();
2875 if (! t.compatible (raw, this))
2876 verify_fail ("incompatible type on stack");
2879 current_state->set_initialized (raw.get_pc (),
2880 current_method->max_locals);
2883 type rt = compute_return_type (method_signature);
2891 type t = check_class_constant (get_ushort ());
2892 if (t.isarray () || t.isinterface (this) || t.isabstract (this))
2893 verify_fail ("type is array, interface, or abstract");
2894 t.set_uninitialized (start_PC, this);
2901 int atype = get_byte ();
2902 // We intentionally have chosen constants to make this
2904 if (atype < boolean_type || atype > long_type)
2905 verify_fail ("type not primitive", start_PC);
2906 pop_type (int_type);
2907 type t (construct_primitive_array_type (type_val (atype)), this);
2912 pop_type (int_type);
2913 push_type (check_class_constant (get_ushort ()).to_array (this));
2915 case op_arraylength:
2917 type t = pop_init_ref (reference_type);
2918 if (! t.isarray () && ! t.isnull ())
2919 verify_fail ("array type expected");
2920 push_type (int_type);
2924 pop_type (type (&java::lang::Throwable::class$, this));
2928 pop_init_ref (reference_type);
2929 push_type (check_class_constant (get_ushort ()));
2932 pop_init_ref (reference_type);
2933 check_class_constant (get_ushort ());
2934 push_type (int_type);
2936 case op_monitorenter:
2937 pop_init_ref (reference_type);
2939 case op_monitorexit:
2940 pop_init_ref (reference_type);
2944 switch (get_byte ())
2947 push_type (get_variable (get_ushort (), int_type));
2950 push_type (get_variable (get_ushort (), long_type));
2953 push_type (get_variable (get_ushort (), float_type));
2956 push_type (get_variable (get_ushort (), double_type));
2959 push_type (get_variable (get_ushort (), reference_type));
2962 set_variable (get_ushort (), pop_type (int_type));
2965 set_variable (get_ushort (), pop_type (long_type));
2968 set_variable (get_ushort (), pop_type (float_type));
2971 set_variable (get_ushort (), pop_type (double_type));
2974 set_variable (get_ushort (), pop_init_ref (reference_type));
2977 handle_ret_insn (get_short ());
2980 get_variable (get_ushort (), int_type);
2984 verify_fail ("unrecognized wide instruction", start_PC);
2988 case op_multianewarray:
2990 type atype = check_class_constant (get_ushort ());
2991 int dim = get_byte ();
2993 verify_fail ("too few dimensions to multianewarray", start_PC);
2994 atype.verify_dimensions (dim, this);
2995 for (int i = 0; i < dim; ++i)
2996 pop_type (int_type);
3002 pop_type (reference_type);
3003 push_jump (get_short ());
3006 push_jump (get_int ());
3010 handle_jsr_insn (get_int ());
3013 // These are unused here, but we call them out explicitly
3014 // so that -Wswitch-enum doesn't complain.
3020 case op_putstatic_1:
3021 case op_putstatic_2:
3022 case op_putstatic_4:
3023 case op_putstatic_8:
3024 case op_putstatic_a:
3026 case op_getfield_2s:
3027 case op_getfield_2u:
3031 case op_getstatic_1:
3032 case op_getstatic_2s:
3033 case op_getstatic_2u:
3034 case op_getstatic_4:
3035 case op_getstatic_8:
3036 case op_getstatic_a:
3038 // Unrecognized opcode.
3039 verify_fail ("unrecognized instruction in verify_instructions_0",
3047 void verify_instructions ()
3050 verify_instructions_0 ();
3053 _Jv_BytecodeVerifier (_Jv_InterpMethod *m)
3055 // We just print the text as utf-8. This is just for debugging
3057 debug_print ("--------------------------------\n");
3058 debug_print ("-- Verifying method `%s'\n", m->self->name->data);
3061 bytecode = m->bytecode ();
3062 exception = m->exceptions ();
3063 current_class = m->defining_class;
3071 ~_Jv_BytecodeVerifier ()
3076 while (utf8_list != NULL)
3078 linked<_Jv_Utf8Const> *n = utf8_list->next;
3079 _Jv_Free (utf8_list->val);
3080 _Jv_Free (utf8_list);
3084 while (isect_list != NULL)
3086 ref_intersection *next = isect_list->alloc_next;
3093 for (int i = 0; i < current_method->code_length; ++i)
3095 linked<state> *iter = states[i];
3096 while (iter != NULL)
3098 linked<state> *next = iter->next;
3110 _Jv_VerifyMethod (_Jv_InterpMethod *meth)
3112 _Jv_BytecodeVerifier v (meth);
3113 v.verify_instructions ();
3116 #endif /* INTERPRETER */