1 // verify.cc - verify bytecode
3 /* Copyright (C) 2001, 2002, 2003, 2004, 2005 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>
22 // On Solaris 10/x86, <signal.h> indirectly includes <ia32/sys/reg.h>, which
23 // defines PC since g++ predefines __EXTENSIONS__. Undef here to avoid clash
24 // with PC member of class _Jv_BytecodeVerifier below.
29 #include <java/lang/Class.h>
30 #include <java/lang/VerifyError.h>
31 #include <java/lang/Throwable.h>
32 #include <java/lang/reflect/Modifier.h>
33 #include <java/lang/StringBuffer.h>
34 #include <java/lang/NoClassDefFoundError.h>
38 #endif /* VERIFY_DEBUG */
41 // This is used to mark states which are not scheduled for
43 #define INVALID_STATE ((state *) -1)
45 static void debug_print (const char *fmt, ...)
46 __attribute__ ((format (printf, 1, 2)));
49 debug_print (MAYBE_UNUSED const char *fmt, ...)
54 vfprintf (stderr, fmt, ap);
56 #endif /* VERIFY_DEBUG */
59 // This started as a fairly ordinary verifier, and for the most part
60 // it remains so. It works in the obvious way, by modeling the effect
61 // of each opcode as it is encountered. For most opcodes, this is a
62 // straightforward operation.
64 // This verifier does not do type merging. It used to, but this
65 // results in difficulty verifying some relatively simple code
66 // involving interfaces, and it pushed some verification work into the
69 // Instead of merging reference types, when we reach a point where two
70 // flows of control merge, we simply keep the union of reference types
71 // from each branch. Then, when we need to verify a fact about a
72 // reference on the stack (e.g., that it is compatible with the
73 // argument type of a method), we check to ensure that all possible
74 // types satisfy the requirement.
76 // Another area this verifier differs from the norm is in its handling
77 // of subroutines. The JVM specification has some confusing things to
78 // say about subroutines. For instance, it makes claims about not
79 // allowing subroutines to merge and it rejects recursive subroutines.
80 // For the most part these are red herrings; we used to try to follow
81 // these things but they lead to problems. For example, the notion of
82 // "being in a subroutine" is not well-defined: is an exception
83 // handler in a subroutine? If you never execute the `ret' but
84 // instead `goto 1' do you remain in the subroutine?
86 // For clarity on what is really required for type safety, read
87 // "Simple Verification Technique for Complex Java Bytecode
88 // Subroutines" by Alessandro Coglio. Among other things this paper
89 // shows that recursive subroutines are not harmful to type safety.
90 // We implement something similar to what he proposes. Note that this
91 // means that this verifier will accept code that is rejected by some
94 // For those not wanting to read the paper, the basic observation is
95 // that we can maintain split states in subroutines. We maintain one
96 // state for each calling `jsr'. In other words, we re-verify a
97 // subroutine once for each caller, using the exact types held by the
98 // callers (as opposed to the old approach of merging types and
99 // keeping a bitmap registering what did or did not change). This
100 // approach lets us continue to verify correctly even when a
101 // subroutine is exited via `goto' or `athrow' and not `ret'.
103 // In some other areas the JVM specification is (mildly) incorrect,
104 // so we diverge. For instance, you cannot
105 // violate type safety by allocating an object with `new' and then
106 // failing to initialize it, no matter how one branches or where one
107 // stores the uninitialized reference. See "Improving the official
108 // specification of Java bytecode verification" by Alessandro Coglio.
110 // Note that there's no real point in enforcing that padding bytes or
111 // the mystery byte of invokeinterface must be 0, but we do that
114 // The verifier is currently neither completely lazy nor eager when it
115 // comes to loading classes. It tries to represent types by name when
116 // possible, and then loads them when it needs to verify a fact about
117 // the type. Checking types by name is valid because we only use
118 // names which come from the current class' constant pool. Since all
119 // such names are looked up using the same class loader, there is no
120 // danger that we might be fooled into comparing different types with
123 // In the future we plan to allow for a completely lazy mode of
124 // operation, where the verifier will construct a list of type
125 // assertions to be checked later.
127 // Some test cases for the verifier live in the "verify" module of the
128 // Mauve test suite. However, some of these are presently
129 // (2004-01-20) believed to be incorrect. (More precisely the notion
130 // of "correct" is not well-defined, and this verifier differs from
131 // others while remaining type-safe.) Some other tests live in the
132 // libgcj test suite.
133 class _Jv_BytecodeVerifier
137 static const int FLAG_INSN_START = 1;
138 static const int FLAG_BRANCH_TARGET = 2;
143 struct ref_intersection;
154 // The PC corresponding to the start of the current instruction.
157 // The current state of the stack, locals, etc.
158 state *current_state;
160 // At each branch target we keep a linked list of all the states we
161 // can process at that point. We'll only have multiple states at a
162 // given PC if they both have different return-address types in the
163 // same stack or local slot. This array is indexed by PC and holds
164 // the list of all such states.
165 linked<state> **states;
167 // We keep a linked list of all the states which we must reverify.
168 // This is the head of the list.
169 state *next_verify_state;
171 // We keep some flags for each instruction. The values are the
172 // FLAG_* constants defined above. This is an array indexed by PC.
175 // The bytecode itself.
176 unsigned char *bytecode;
178 _Jv_InterpException *exception;
181 jclass current_class;
183 _Jv_InterpMethod *current_method;
185 // A linked list of utf8 objects we allocate.
186 linked<_Jv_Utf8Const> *utf8_list;
188 // A linked list of all ref_intersection objects we allocate.
189 ref_intersection *isect_list;
191 // Create a new Utf-8 constant and return it. We do this to avoid
192 // having our Utf-8 constants prematurely collected.
193 _Jv_Utf8Const *make_utf8_const (char *s, int len)
195 linked<_Jv_Utf8Const> *lu = (linked<_Jv_Utf8Const> *)
196 _Jv_Malloc (sizeof (linked<_Jv_Utf8Const>)
197 + _Jv_Utf8Const::space_needed(s, len));
198 _Jv_Utf8Const *r = (_Jv_Utf8Const *) (lu + 1);
201 lu->next = utf8_list;
207 __attribute__ ((__noreturn__)) void verify_fail (char *s, jint pc = -1)
209 using namespace java::lang;
210 StringBuffer *buf = new StringBuffer ();
212 buf->append (JvNewStringLatin1 ("verification failed"));
217 buf->append (JvNewStringLatin1 (" at PC "));
221 _Jv_InterpMethod *method = current_method;
222 buf->append (JvNewStringLatin1 (" in "));
223 buf->append (current_class->getName());
224 buf->append ((jchar) ':');
225 buf->append (method->get_method()->name->toString());
226 buf->append ((jchar) '(');
227 buf->append (method->get_method()->signature->toString());
228 buf->append ((jchar) ')');
230 buf->append (JvNewStringLatin1 (": "));
231 buf->append (JvNewStringLatin1 (s));
232 throw new java::lang::VerifyError (buf->toString ());
235 // This enum holds a list of tags for all the different types we
236 // need to handle. Reference types are treated specially by the
242 // The values for primitive types are chosen to correspond to values
243 // specified to newarray.
253 // Used when overwriting second word of a double or long in the
254 // local variables. Also used after merging local variable states
255 // to indicate an unusable value.
258 // This is the second word of a two-word value, i.e., a double or
262 // Everything after `reference_type' must be a reference type.
265 uninitialized_reference_type
268 // This represents a merged class type. Some verifiers (including
269 // earlier versions of this one) will compute the intersection of
270 // two class types when merging states. However, this loses
271 // critical information about interfaces implemented by the various
272 // classes. So instead we keep track of all the actual classes that
274 struct ref_intersection
276 // Whether or not this type has been resolved.
282 // For a resolved reference type, this is a pointer to the class.
284 // For other reference types, this it the name of the class.
288 // Link to the next reference in the intersection.
289 ref_intersection *ref_next;
291 // This is used to keep track of all the allocated
292 // ref_intersection objects, so we can free them.
293 // FIXME: we should allocate these in chunks.
294 ref_intersection *alloc_next;
296 ref_intersection (jclass klass, _Jv_BytecodeVerifier *verifier)
301 alloc_next = verifier->isect_list;
302 verifier->isect_list = this;
305 ref_intersection (_Jv_Utf8Const *name, _Jv_BytecodeVerifier *verifier)
310 alloc_next = verifier->isect_list;
311 verifier->isect_list = this;
314 ref_intersection (ref_intersection *dup, ref_intersection *tail,
315 _Jv_BytecodeVerifier *verifier)
318 is_resolved = dup->is_resolved;
320 alloc_next = verifier->isect_list;
321 verifier->isect_list = this;
324 bool equals (ref_intersection *other, _Jv_BytecodeVerifier *verifier)
326 if (! is_resolved && ! other->is_resolved
327 && _Jv_equalUtf8Consts (data.name, other->data.name))
331 if (! other->is_resolved)
332 other->resolve (verifier);
333 return data.klass == other->data.klass;
336 // Merge THIS type into OTHER, returning the result. This will
337 // return OTHER if all the classes in THIS already appear in
339 ref_intersection *merge (ref_intersection *other,
340 _Jv_BytecodeVerifier *verifier)
342 ref_intersection *tail = other;
343 for (ref_intersection *self = this; self != NULL; self = self->ref_next)
346 for (ref_intersection *iter = other; iter != NULL;
347 iter = iter->ref_next)
349 if (iter->equals (self, verifier))
357 tail = new ref_intersection (self, tail, verifier);
362 void resolve (_Jv_BytecodeVerifier *verifier)
367 using namespace java::lang;
368 java::lang::ClassLoader *loader
369 = verifier->current_class->getClassLoaderInternal();
370 // We might see either kind of name. Sigh.
371 if (data.name->first() == 'L' && data.name->limit()[-1] == ';')
373 data.klass = _Jv_FindClassFromSignature (data.name->chars(), loader);
374 if (data.klass == NULL)
375 throw new java::lang::NoClassDefFoundError(data.name->toString());
378 data.klass = Class::forName (_Jv_NewStringUtf8Const (data.name),
383 // See if an object of type OTHER can be assigned to an object of
384 // type *THIS. This might resolve classes in one chain or the
386 bool compatible (ref_intersection *other,
387 _Jv_BytecodeVerifier *verifier)
389 ref_intersection *self = this;
391 for (; self != NULL; self = self->ref_next)
393 ref_intersection *other_iter = other;
395 for (; other_iter != NULL; other_iter = other_iter->ref_next)
397 // Avoid resolving if possible.
398 if (! self->is_resolved
399 && ! other_iter->is_resolved
400 && _Jv_equalUtf8Consts (self->data.name,
401 other_iter->data.name))
404 if (! self->is_resolved)
405 self->resolve(verifier);
406 if (! other_iter->is_resolved)
407 other_iter->resolve(verifier);
409 if (! is_assignable_from_slow (self->data.klass,
410 other_iter->data.klass))
420 // assert (ref_next == NULL);
422 return data.klass->isArray ();
424 return data.name->first() == '[';
427 bool isinterface (_Jv_BytecodeVerifier *verifier)
429 // assert (ref_next == NULL);
432 return data.klass->isInterface ();
435 bool isabstract (_Jv_BytecodeVerifier *verifier)
437 // assert (ref_next == NULL);
440 using namespace java::lang::reflect;
441 return Modifier::isAbstract (data.klass->getModifiers ());
444 jclass getclass (_Jv_BytecodeVerifier *verifier)
451 int count_dimensions ()
456 jclass k = data.klass;
457 while (k->isArray ())
459 k = k->getComponentType ();
465 char *p = data.name->chars();
472 void *operator new (size_t bytes)
474 return _Jv_Malloc (bytes);
477 void operator delete (void *mem)
483 // Return the type_val corresponding to a primitive signature
484 // character. For instance `I' returns `int.class'.
485 type_val get_type_val_for_signature (jchar sig)
518 verify_fail ("invalid signature");
523 // Return the type_val corresponding to a primitive class.
524 type_val get_type_val_for_signature (jclass k)
526 return get_type_val_for_signature ((jchar) k->method_count);
529 // This is like _Jv_IsAssignableFrom, but it works even if SOURCE or
530 // TARGET haven't been prepared.
531 static bool is_assignable_from_slow (jclass target, jclass source)
533 // First, strip arrays.
534 while (target->isArray ())
536 // If target is array, source must be as well.
537 if (! source->isArray ())
539 target = target->getComponentType ();
540 source = source->getComponentType ();
544 if (target == &java::lang::Object::class$)
549 if (source == target)
552 if (target->isPrimitive () || source->isPrimitive ())
555 if (target->isInterface ())
557 for (int i = 0; i < source->interface_count; ++i)
559 // We use a recursive call because we also need to
560 // check superinterfaces.
561 if (is_assignable_from_slow (target, source->getInterface (i)))
565 source = source->getSuperclass ();
567 while (source != NULL);
572 // The `type' class is used to represent a single type in the
579 // For reference types, the representation of the type.
580 ref_intersection *klass;
582 // This is used in two situations.
584 // First, when constructing a new object, it is the PC of the
585 // `new' instruction which created the object. We use the special
586 // value UNINIT to mean that this is uninitialized. The special
587 // value SELF is used for the case where the current method is
588 // itself the <init> method. the special value EITHER is used
589 // when we may optionally allow either an uninitialized or
590 // initialized reference to match.
592 // Second, when the key is return_address_type, this holds the PC
593 // of the instruction following the `jsr'.
596 static const int UNINIT = -2;
597 static const int SELF = -1;
598 static const int EITHER = -3;
600 // Basic constructor.
603 key = unsuitable_type;
608 // Make a new instance given the type tag. We assume a generic
609 // `reference_type' means Object.
613 // For reference_type, if KLASS==NULL then that means we are
614 // looking for a generic object of any kind, including an
615 // uninitialized reference.
620 // Make a new instance given a class.
621 type (jclass k, _Jv_BytecodeVerifier *verifier)
623 key = reference_type;
624 klass = new ref_intersection (k, verifier);
628 // Make a new instance given the name of a class.
629 type (_Jv_Utf8Const *n, _Jv_BytecodeVerifier *verifier)
631 key = reference_type;
632 klass = new ref_intersection (n, verifier);
644 // These operators are required because libgcj can't link in
646 void *operator new[] (size_t bytes)
648 return _Jv_Malloc (bytes);
651 void operator delete[] (void *mem)
656 type& operator= (type_val k)
664 type& operator= (const type& t)
672 // Promote a numeric type.
675 if (key == boolean_type || key == char_type
676 || key == byte_type || key == short_type)
681 // Mark this type as the uninitialized result of `new'.
682 void set_uninitialized (int npc, _Jv_BytecodeVerifier *verifier)
684 if (key == reference_type)
685 key = uninitialized_reference_type;
687 verifier->verify_fail ("internal error in type::uninitialized");
691 // Mark this type as now initialized.
692 void set_initialized (int npc)
694 if (npc != UNINIT && pc == npc && key == uninitialized_reference_type)
696 key = reference_type;
701 // Mark this type as a particular return address.
702 void set_return_address (int npc)
707 // Return true if this type and type OTHER are considered
708 // mergeable for the purposes of state merging. This is related
709 // to subroutine handling. For this purpose two types are
710 // considered unmergeable if they are both return-addresses but
711 // have different PCs.
712 bool state_mergeable_p (const type &other) const
714 return (key != return_address_type
715 || other.key != return_address_type
719 // Return true if an object of type K can be assigned to a variable
720 // of type *THIS. Handle various special cases too. Might modify
721 // *THIS or K. Note however that this does not perform numeric
723 bool compatible (type &k, _Jv_BytecodeVerifier *verifier)
725 // Any type is compatible with the unsuitable type.
726 if (key == unsuitable_type)
729 if (key < reference_type || k.key < reference_type)
732 // The `null' type is convertible to any initialized reference
734 if (key == null_type)
735 return k.key != uninitialized_reference_type;
736 if (k.key == null_type)
737 return key != uninitialized_reference_type;
739 // A special case for a generic reference.
743 verifier->verify_fail ("programmer error in type::compatible");
745 // Handle the special 'EITHER' case, which is only used in a
746 // special case of 'putfield'. Note that we only need to handle
747 // this on the LHS of a check.
748 if (! isinitialized () && pc == EITHER)
750 // If the RHS is uninitialized, it must be an uninitialized
752 if (! k.isinitialized () && k.pc != SELF)
755 else if (isinitialized () != k.isinitialized ())
757 // An initialized type and an uninitialized type are not
758 // otherwise compatible.
763 // Two uninitialized objects are compatible if either:
764 // * The PCs are identical, or
765 // * One PC is UNINIT.
766 if (! isinitialized ())
768 if (pc != k.pc && pc != UNINIT && k.pc != UNINIT)
773 return klass->compatible(k.klass, verifier);
776 bool equals (const type &other, _Jv_BytecodeVerifier *vfy)
778 // Only works for reference types.
779 if ((key != reference_type
780 && key != uninitialized_reference_type)
781 || (other.key != reference_type
782 && other.key != uninitialized_reference_type))
784 // Only for single-valued types.
785 if (klass->ref_next || other.klass->ref_next)
787 return klass->equals (other.klass, vfy);
792 return key == void_type;
797 return key == long_type || key == double_type;
800 // Return number of stack or local variable slots taken by this
804 return iswide () ? 2 : 1;
807 bool isarray () const
809 // We treat null_type as not an array. This is ok based on the
810 // current uses of this method.
811 if (key == reference_type)
812 return klass->isarray ();
818 return key == null_type;
821 bool isinterface (_Jv_BytecodeVerifier *verifier)
823 if (key != reference_type)
825 return klass->isinterface (verifier);
828 bool isabstract (_Jv_BytecodeVerifier *verifier)
830 if (key != reference_type)
832 return klass->isabstract (verifier);
835 // Return the element type of an array.
836 type element_type (_Jv_BytecodeVerifier *verifier)
838 if (key != reference_type)
839 verifier->verify_fail ("programmer error in type::element_type()", -1);
841 jclass k = klass->getclass (verifier)->getComponentType ();
842 if (k->isPrimitive ())
843 return type (verifier->get_type_val_for_signature (k));
844 return type (k, verifier);
847 // Return the array type corresponding to an initialized
848 // reference. We could expand this to work for other kinds of
849 // types, but currently we don't need to.
850 type to_array (_Jv_BytecodeVerifier *verifier)
852 if (key != reference_type)
853 verifier->verify_fail ("internal error in type::to_array()");
855 jclass k = klass->getclass (verifier);
856 return type (_Jv_GetArrayClass (k, k->getClassLoaderInternal()),
860 bool isreference () const
862 return key >= reference_type;
870 bool isinitialized () const
872 return key == reference_type || key == null_type;
875 bool isresolved () const
877 return (key == reference_type
879 || key == uninitialized_reference_type);
882 void verify_dimensions (int ndims, _Jv_BytecodeVerifier *verifier)
884 // The way this is written, we don't need to check isarray().
885 if (key != reference_type)
886 verifier->verify_fail ("internal error in verify_dimensions:"
887 " not a reference type");
889 if (klass->count_dimensions () < ndims)
890 verifier->verify_fail ("array type has fewer dimensions"
894 // Merge OLD_TYPE into this. On error throw exception. Return
895 // true if the merge caused a type change.
896 bool merge (type& old_type, bool local_semantics,
897 _Jv_BytecodeVerifier *verifier)
899 bool changed = false;
900 bool refo = old_type.isreference ();
901 bool refn = isreference ();
904 if (old_type.key == null_type)
906 else if (key == null_type)
911 else if (isinitialized () != old_type.isinitialized ())
912 verifier->verify_fail ("merging initialized and uninitialized types");
915 if (! isinitialized ())
919 else if (old_type.pc == UNINIT)
921 else if (pc != old_type.pc)
922 verifier->verify_fail ("merging different uninitialized types");
925 ref_intersection *merged = old_type.klass->merge (klass,
934 else if (refo || refn || key != old_type.key)
938 // If we already have an `unsuitable' type, then we
939 // don't need to change again.
940 if (key != unsuitable_type)
942 key = unsuitable_type;
947 verifier->verify_fail ("unmergeable type");
953 void print (void) const
958 case boolean_type: c = 'Z'; break;
959 case byte_type: c = 'B'; break;
960 case char_type: c = 'C'; break;
961 case short_type: c = 'S'; break;
962 case int_type: c = 'I'; break;
963 case long_type: c = 'J'; break;
964 case float_type: c = 'F'; break;
965 case double_type: c = 'D'; break;
966 case void_type: c = 'V'; break;
967 case unsuitable_type: c = '-'; break;
968 case return_address_type: c = 'r'; break;
969 case continuation_type: c = '+'; break;
970 case reference_type: c = 'L'; break;
971 case null_type: c = '@'; break;
972 case uninitialized_reference_type: c = 'U'; break;
974 debug_print ("%c", c);
976 #endif /* VERIFY_DEBUG */
979 // This class holds all the state information we need for a given
983 // The current top of the stack, in terms of slots.
985 // The current depth of the stack. This will be larger than
986 // STACKTOP when wide types are on the stack.
990 // The local variables.
992 // We keep track of the type of `this' specially. This is used to
993 // ensure that an instance initializer invokes another initializer
994 // on `this' before returning. We must keep track of this
995 // specially because otherwise we might be confused by code which
996 // assigns to locals[0] (overwriting `this') and then returns
997 // without really initializing.
1000 // The PC for this state. This is only valid on states which are
1001 // permanently attached to a given PC. For an object like
1002 // `current_state', which is used transiently, this has no
1005 // We keep a linked list of all states requiring reverification.
1006 // If this is the special value INVALID_STATE then this state is
1007 // not on the list. NULL marks the end of the linked list.
1010 // NO_NEXT is the PC value meaning that a new state must be
1011 // acquired from the verification list.
1012 static const int NO_NEXT = -1;
1019 next = INVALID_STATE;
1022 state (int max_stack, int max_locals)
1027 stack = new type[max_stack];
1028 for (int i = 0; i < max_stack; ++i)
1029 stack[i] = unsuitable_type;
1030 locals = new type[max_locals];
1031 for (int i = 0; i < max_locals; ++i)
1032 locals[i] = unsuitable_type;
1034 next = INVALID_STATE;
1037 state (const state *orig, int max_stack, int max_locals)
1039 stack = new type[max_stack];
1040 locals = new type[max_locals];
1041 copy (orig, max_stack, max_locals);
1043 next = INVALID_STATE;
1054 void *operator new[] (size_t bytes)
1056 return _Jv_Malloc (bytes);
1059 void operator delete[] (void *mem)
1064 void *operator new (size_t bytes)
1066 return _Jv_Malloc (bytes);
1069 void operator delete (void *mem)
1074 void copy (const state *copy, int max_stack, int max_locals)
1076 stacktop = copy->stacktop;
1077 stackdepth = copy->stackdepth;
1078 for (int i = 0; i < max_stack; ++i)
1079 stack[i] = copy->stack[i];
1080 for (int i = 0; i < max_locals; ++i)
1081 locals[i] = copy->locals[i];
1083 this_type = copy->this_type;
1084 // Don't modify `next' or `pc'.
1087 // Modify this state to reflect entry to an exception handler.
1088 void set_exception (type t, int max_stack)
1093 for (int i = stacktop; i < max_stack; ++i)
1094 stack[i] = unsuitable_type;
1097 inline int get_pc () const
1102 void set_pc (int npc)
1107 // Merge STATE_OLD into this state. Destructively modifies this
1108 // state. Returns true if the new state was in fact changed.
1109 // Will throw an exception if the states are not mergeable.
1110 bool merge (state *state_old, int max_locals,
1111 _Jv_BytecodeVerifier *verifier)
1113 bool changed = false;
1115 // Special handling for `this'. If one or the other is
1116 // uninitialized, then the merge is uninitialized.
1117 if (this_type.isinitialized ())
1118 this_type = state_old->this_type;
1121 if (state_old->stacktop != stacktop) // FIXME stackdepth instead?
1122 verifier->verify_fail ("stack sizes differ");
1123 for (int i = 0; i < state_old->stacktop; ++i)
1125 if (stack[i].merge (state_old->stack[i], false, verifier))
1129 // Merge local variables.
1130 for (int i = 0; i < max_locals; ++i)
1132 if (locals[i].merge (state_old->locals[i], true, verifier))
1139 // Ensure that `this' has been initialized.
1140 void check_this_initialized (_Jv_BytecodeVerifier *verifier)
1142 if (this_type.isreference () && ! this_type.isinitialized ())
1143 verifier->verify_fail ("`this' is uninitialized");
1146 // Set type of `this'.
1147 void set_this_type (const type &k)
1152 // Mark each `new'd object we know of that was allocated at PC as
1154 void set_initialized (int pc, int max_locals)
1156 for (int i = 0; i < stacktop; ++i)
1157 stack[i].set_initialized (pc);
1158 for (int i = 0; i < max_locals; ++i)
1159 locals[i].set_initialized (pc);
1160 this_type.set_initialized (pc);
1163 // This tests to see whether two states can be considered "merge
1164 // compatible". If both states have a return-address in the same
1165 // slot, and the return addresses are different, then they are not
1166 // compatible and we must not try to merge them.
1167 bool state_mergeable_p (state *other, int max_locals,
1168 _Jv_BytecodeVerifier *verifier)
1170 // This is tricky: if the stack sizes differ, then not only are
1171 // these not mergeable, but in fact we should give an error, as
1172 // we've found two execution paths that reach a branch target
1173 // with different stack depths. FIXME stackdepth instead?
1174 if (stacktop != other->stacktop)
1175 verifier->verify_fail ("stack sizes differ");
1177 for (int i = 0; i < stacktop; ++i)
1178 if (! stack[i].state_mergeable_p (other->stack[i]))
1180 for (int i = 0; i < max_locals; ++i)
1181 if (! locals[i].state_mergeable_p (other->locals[i]))
1186 void reverify (_Jv_BytecodeVerifier *verifier)
1188 if (next == INVALID_STATE)
1190 next = verifier->next_verify_state;
1191 verifier->next_verify_state = this;
1196 void print (const char *leader, int pc,
1197 int max_stack, int max_locals) const
1199 debug_print ("%s [%4d]: [stack] ", leader, pc);
1201 for (i = 0; i < stacktop; ++i)
1203 for (; i < max_stack; ++i)
1205 debug_print (" [local] ");
1206 for (i = 0; i < max_locals; ++i)
1208 debug_print (" | %p\n", this);
1211 inline void print (const char *, int, int, int) const
1214 #endif /* VERIFY_DEBUG */
1219 if (current_state->stacktop <= 0)
1220 verify_fail ("stack empty");
1221 type r = current_state->stack[--current_state->stacktop];
1222 current_state->stackdepth -= r.depth ();
1223 if (current_state->stackdepth < 0)
1224 verify_fail ("stack empty", start_PC);
1230 type r = pop_raw ();
1232 verify_fail ("narrow pop of wide type");
1236 type pop_type (type match)
1239 type t = pop_raw ();
1240 if (! match.compatible (t, this))
1241 verify_fail ("incompatible type on stack");
1245 // Pop a reference which is guaranteed to be initialized. MATCH
1246 // doesn't have to be a reference type; in this case this acts like
1248 type pop_init_ref (type match)
1250 type t = pop_raw ();
1251 if (t.isreference () && ! t.isinitialized ())
1252 verify_fail ("initialized reference required");
1253 else if (! match.compatible (t, this))
1254 verify_fail ("incompatible type on stack");
1258 // Pop a reference type or a return address.
1259 type pop_ref_or_return ()
1261 type t = pop_raw ();
1262 if (! t.isreference () && t.key != return_address_type)
1263 verify_fail ("expected reference or return address on stack");
1267 void push_type (type t)
1269 // If T is a numeric type like short, promote it to int.
1272 int depth = t.depth ();
1273 if (current_state->stackdepth + depth > current_method->max_stack)
1274 verify_fail ("stack overflow");
1275 current_state->stack[current_state->stacktop++] = t;
1276 current_state->stackdepth += depth;
1279 void set_variable (int index, type t)
1281 // If T is a numeric type like short, promote it to int.
1284 int depth = t.depth ();
1285 if (index > current_method->max_locals - depth)
1286 verify_fail ("invalid local variable");
1287 current_state->locals[index] = t;
1290 current_state->locals[index + 1] = continuation_type;
1291 if (index > 0 && current_state->locals[index - 1].iswide ())
1292 current_state->locals[index - 1] = unsuitable_type;
1295 type get_variable (int index, type t)
1297 int depth = t.depth ();
1298 if (index > current_method->max_locals - depth)
1299 verify_fail ("invalid local variable");
1300 if (! t.compatible (current_state->locals[index], this))
1301 verify_fail ("incompatible type in local variable");
1304 type t (continuation_type);
1305 if (! current_state->locals[index + 1].compatible (t, this))
1306 verify_fail ("invalid local variable");
1308 return current_state->locals[index];
1311 // Make sure ARRAY is an array type and that its elements are
1312 // compatible with type ELEMENT. Returns the actual element type.
1313 type require_array_type (type array, type element)
1315 // An odd case. Here we just pretend that everything went ok. If
1316 // the requested element type is some kind of reference, return
1317 // the null type instead.
1318 if (array.isnull ())
1319 return element.isreference () ? type (null_type) : element;
1321 if (! array.isarray ())
1322 verify_fail ("array required");
1324 type t = array.element_type (this);
1325 if (! element.compatible (t, this))
1327 // Special case for byte arrays, which must also be boolean
1330 if (element.key == byte_type)
1332 type e2 (boolean_type);
1333 ok = e2.compatible (t, this);
1336 verify_fail ("incompatible array element type");
1339 // Return T and not ELEMENT, because T might be specialized.
1345 if (PC >= current_method->code_length)
1346 verify_fail ("premature end of bytecode");
1347 return (jint) bytecode[PC++] & 0xff;
1352 jint b1 = get_byte ();
1353 jint b2 = get_byte ();
1354 return (jint) ((b1 << 8) | b2) & 0xffff;
1359 jint b1 = get_byte ();
1360 jint b2 = get_byte ();
1361 jshort s = (b1 << 8) | b2;
1367 jint b1 = get_byte ();
1368 jint b2 = get_byte ();
1369 jint b3 = get_byte ();
1370 jint b4 = get_byte ();
1371 return (b1 << 24) | (b2 << 16) | (b3 << 8) | b4;
1374 int compute_jump (int offset)
1376 int npc = start_PC + offset;
1377 if (npc < 0 || npc >= current_method->code_length)
1378 verify_fail ("branch out of range", start_PC);
1382 // Add a new state to the state list at NPC.
1383 state *add_new_state (int npc, state *old_state)
1385 state *new_state = new state (old_state, current_method->max_stack,
1386 current_method->max_locals);
1387 debug_print ("== New state in add_new_state\n");
1388 new_state->print ("New", npc, current_method->max_stack,
1389 current_method->max_locals);
1390 linked<state> *nlink
1391 = (linked<state> *) _Jv_Malloc (sizeof (linked<state>));
1392 nlink->val = new_state;
1393 nlink->next = states[npc];
1394 states[npc] = nlink;
1395 new_state->set_pc (npc);
1399 // Merge the indicated state into the state at the branch target and
1400 // schedule a new PC if there is a change. NPC is the PC of the
1401 // branch target, and FROM_STATE is the state at the source of the
1402 // branch. This method returns true if the destination state
1403 // changed and requires reverification, false otherwise.
1404 void merge_into (int npc, state *from_state)
1406 // Iterate over all target states and merge our state into each,
1407 // if applicable. FIXME one improvement we could make here is
1408 // "state destruction". Merging a new state into an existing one
1409 // might cause a return_address_type to be merged to
1410 // unsuitable_type. In this case the resulting state may now be
1411 // mergeable with other states currently held in parallel at this
1412 // location. So in this situation we could pairwise compare and
1413 // reduce the number of parallel states.
1414 bool applicable = false;
1415 for (linked<state> *iter = states[npc]; iter != NULL; iter = iter->next)
1417 state *new_state = iter->val;
1418 if (new_state->state_mergeable_p (from_state,
1419 current_method->max_locals, this))
1423 debug_print ("== Merge states in merge_into\n");
1424 from_state->print ("Frm", start_PC, current_method->max_stack,
1425 current_method->max_locals);
1426 new_state->print (" To", npc, current_method->max_stack,
1427 current_method->max_locals);
1428 bool changed = new_state->merge (from_state,
1429 current_method->max_locals,
1431 new_state->print ("New", npc, current_method->max_stack,
1432 current_method->max_locals);
1435 new_state->reverify (this);
1441 // Either we don't yet have a state at NPC, or we have a
1442 // return-address type that is in conflict with all existing
1443 // state. So, we need to create a new entry.
1444 state *new_state = add_new_state (npc, from_state);
1445 // A new state added in this way must always be reverified.
1446 new_state->reverify (this);
1450 void push_jump (int offset)
1452 int npc = compute_jump (offset);
1453 // According to the JVM Spec, we need to check for uninitialized
1454 // objects here. However, this does not actually affect type
1455 // safety, and the Eclipse java compiler generates code that
1456 // violates this constraint.
1457 merge_into (npc, current_state);
1460 void push_exception_jump (type t, int pc)
1462 // According to the JVM Spec, we need to check for uninitialized
1463 // objects here. However, this does not actually affect type
1464 // safety, and the Eclipse java compiler generates code that
1465 // violates this constraint.
1466 state s (current_state, current_method->max_stack,
1467 current_method->max_locals);
1468 if (current_method->max_stack < 1)
1469 verify_fail ("stack overflow at exception handler");
1470 s.set_exception (t, current_method->max_stack);
1471 merge_into (pc, &s);
1476 state *new_state = next_verify_state;
1477 if (new_state == INVALID_STATE)
1478 verify_fail ("programmer error in pop_jump");
1479 if (new_state != NULL)
1481 next_verify_state = new_state->next;
1482 new_state->next = INVALID_STATE;
1487 void invalidate_pc ()
1489 PC = state::NO_NEXT;
1492 void note_branch_target (int pc)
1494 // Don't check `pc <= PC', because we've advanced PC after
1495 // fetching the target and we haven't yet checked the next
1497 if (pc < PC && ! (flags[pc] & FLAG_INSN_START))
1498 verify_fail ("branch not to instruction start", start_PC);
1499 flags[pc] |= FLAG_BRANCH_TARGET;
1502 void skip_padding ()
1504 while ((PC % 4) > 0)
1505 if (get_byte () != 0)
1506 verify_fail ("found nonzero padding byte");
1509 // Do the work for a `ret' instruction. INDEX is the index into the
1511 void handle_ret_insn (int index)
1513 type ret_addr = get_variable (index, return_address_type);
1514 // It would be nice if we could do this. However, the JVM Spec
1515 // doesn't say that this is what happens. It is implied that
1516 // reusing a return address is invalid, but there's no actual
1517 // prohibition against it.
1518 // set_variable (index, unsuitable_type);
1520 int npc = ret_addr.get_pc ();
1521 // We might be returning to a `jsr' that is at the end of the
1522 // bytecode. This is ok if we never return from the called
1523 // subroutine, but if we see this here it is an error.
1524 if (npc >= current_method->code_length)
1525 verify_fail ("fell off end");
1527 // According to the JVM Spec, we need to check for uninitialized
1528 // objects here. However, this does not actually affect type
1529 // safety, and the Eclipse java compiler generates code that
1530 // violates this constraint.
1531 merge_into (npc, current_state);
1535 void handle_jsr_insn (int offset)
1537 int npc = compute_jump (offset);
1539 // According to the JVM Spec, we need to check for uninitialized
1540 // objects here. However, this does not actually affect type
1541 // safety, and the Eclipse java compiler generates code that
1542 // violates this constraint.
1544 // Modify our state as appropriate for entry into a subroutine.
1545 type ret_addr (return_address_type);
1546 ret_addr.set_return_address (PC);
1547 push_type (ret_addr);
1548 merge_into (npc, current_state);
1552 jclass construct_primitive_array_type (type_val prim)
1558 k = JvPrimClass (boolean);
1561 k = JvPrimClass (char);
1564 k = JvPrimClass (float);
1567 k = JvPrimClass (double);
1570 k = JvPrimClass (byte);
1573 k = JvPrimClass (short);
1576 k = JvPrimClass (int);
1579 k = JvPrimClass (long);
1582 // These aren't used here but we call them out to avoid
1585 case unsuitable_type:
1586 case return_address_type:
1587 case continuation_type:
1588 case reference_type:
1590 case uninitialized_reference_type:
1592 verify_fail ("unknown type in construct_primitive_array_type");
1594 k = _Jv_GetArrayClass (k, NULL);
1598 // This pass computes the location of branch targets and also
1599 // instruction starts.
1600 void branch_prepass ()
1602 flags = (char *) _Jv_Malloc (current_method->code_length);
1604 for (int i = 0; i < current_method->code_length; ++i)
1608 while (PC < current_method->code_length)
1610 // Set `start_PC' early so that error checking can have the
1613 flags[PC] |= FLAG_INSN_START;
1615 java_opcode opcode = (java_opcode) bytecode[PC++];
1619 case op_aconst_null:
1755 case op_monitorenter:
1756 case op_monitorexit:
1764 case op_arraylength:
1796 case op_invokespecial:
1797 case op_invokestatic:
1798 case op_invokevirtual:
1802 case op_multianewarray:
1825 note_branch_target (compute_jump (get_short ()));
1828 case op_tableswitch:
1831 note_branch_target (compute_jump (get_int ()));
1832 jint low = get_int ();
1833 jint hi = get_int ();
1835 verify_fail ("invalid tableswitch", start_PC);
1836 for (int i = low; i <= hi; ++i)
1837 note_branch_target (compute_jump (get_int ()));
1841 case op_lookupswitch:
1844 note_branch_target (compute_jump (get_int ()));
1845 int npairs = get_int ();
1847 verify_fail ("too few pairs in lookupswitch", start_PC);
1848 while (npairs-- > 0)
1851 note_branch_target (compute_jump (get_int ()));
1856 case op_invokeinterface:
1864 opcode = (java_opcode) get_byte ();
1866 if (opcode == op_iinc)
1873 note_branch_target (compute_jump (get_int ()));
1876 // These are unused here, but we call them out explicitly
1877 // so that -Wswitch-enum doesn't complain.
1883 case op_putstatic_1:
1884 case op_putstatic_2:
1885 case op_putstatic_4:
1886 case op_putstatic_8:
1887 case op_putstatic_a:
1889 case op_getfield_2s:
1890 case op_getfield_2u:
1894 case op_getstatic_1:
1895 case op_getstatic_2s:
1896 case op_getstatic_2u:
1897 case op_getstatic_4:
1898 case op_getstatic_8:
1899 case op_getstatic_a:
1901 verify_fail ("unrecognized instruction in branch_prepass",
1905 // See if any previous branch tried to branch to the middle of
1906 // this instruction.
1907 for (int pc = start_PC + 1; pc < PC; ++pc)
1909 if ((flags[pc] & FLAG_BRANCH_TARGET))
1910 verify_fail ("branch to middle of instruction", pc);
1914 // Verify exception handlers.
1915 for (int i = 0; i < current_method->exc_count; ++i)
1917 if (! (flags[exception[i].handler_pc.i] & FLAG_INSN_START))
1918 verify_fail ("exception handler not at instruction start",
1919 exception[i].handler_pc.i);
1920 if (! (flags[exception[i].start_pc.i] & FLAG_INSN_START))
1921 verify_fail ("exception start not at instruction start",
1922 exception[i].start_pc.i);
1923 if (exception[i].end_pc.i != current_method->code_length
1924 && ! (flags[exception[i].end_pc.i] & FLAG_INSN_START))
1925 verify_fail ("exception end not at instruction start",
1926 exception[i].end_pc.i);
1928 flags[exception[i].handler_pc.i] |= FLAG_BRANCH_TARGET;
1932 void check_pool_index (int index)
1934 if (index < 0 || index >= current_class->constants.size)
1935 verify_fail ("constant pool index out of range", start_PC);
1938 type check_class_constant (int index)
1940 check_pool_index (index);
1941 _Jv_Constants *pool = ¤t_class->constants;
1942 if (pool->tags[index] == JV_CONSTANT_ResolvedClass)
1943 return type (pool->data[index].clazz, this);
1944 else if (pool->tags[index] == JV_CONSTANT_Class)
1945 return type (pool->data[index].utf8, this);
1946 verify_fail ("expected class constant", start_PC);
1949 type check_constant (int index)
1951 check_pool_index (index);
1952 _Jv_Constants *pool = ¤t_class->constants;
1953 int tag = pool->tags[index];
1954 if (tag == JV_CONSTANT_ResolvedString || tag == JV_CONSTANT_String)
1955 return type (&java::lang::String::class$, this);
1956 else if (tag == JV_CONSTANT_Integer)
1957 return type (int_type);
1958 else if (tag == JV_CONSTANT_Float)
1959 return type (float_type);
1960 else if (current_method->is_15
1961 && (tag == JV_CONSTANT_ResolvedClass || tag == JV_CONSTANT_Class))
1962 return type (&java::lang::Class::class$, this);
1963 verify_fail ("String, int, or float constant expected", start_PC);
1966 type check_wide_constant (int index)
1968 check_pool_index (index);
1969 _Jv_Constants *pool = ¤t_class->constants;
1970 if (pool->tags[index] == JV_CONSTANT_Long)
1971 return type (long_type);
1972 else if (pool->tags[index] == JV_CONSTANT_Double)
1973 return type (double_type);
1974 verify_fail ("long or double constant expected", start_PC);
1977 // Helper for both field and method. These are laid out the same in
1978 // the constant pool.
1979 type handle_field_or_method (int index, int expected,
1980 _Jv_Utf8Const **name,
1981 _Jv_Utf8Const **fmtype)
1983 check_pool_index (index);
1984 _Jv_Constants *pool = ¤t_class->constants;
1985 if (pool->tags[index] != expected)
1986 verify_fail ("didn't see expected constant", start_PC);
1987 // Once we know we have a Fieldref or Methodref we assume that it
1988 // is correctly laid out in the constant pool. I think the code
1989 // in defineclass.cc guarantees this.
1990 _Jv_ushort class_index, name_and_type_index;
1991 _Jv_loadIndexes (&pool->data[index],
1993 name_and_type_index);
1994 _Jv_ushort name_index, desc_index;
1995 _Jv_loadIndexes (&pool->data[name_and_type_index],
1996 name_index, desc_index);
1998 *name = pool->data[name_index].utf8;
1999 *fmtype = pool->data[desc_index].utf8;
2001 return check_class_constant (class_index);
2004 // Return field's type, compute class' type if requested.
2005 // If PUTFIELD is true, use the special 'putfield' semantics.
2006 type check_field_constant (int index, type *class_type = NULL,
2007 bool putfield = false)
2009 _Jv_Utf8Const *name, *field_type;
2010 type ct = handle_field_or_method (index,
2011 JV_CONSTANT_Fieldref,
2012 &name, &field_type);
2016 if (field_type->first() == '[' || field_type->first() == 'L')
2017 result = type (field_type, this);
2019 result = get_type_val_for_signature (field_type->first());
2021 // We have an obscure special case here: we can use `putfield' on
2022 // a field declared in this class, even if `this' has not yet been
2025 && ! current_state->this_type.isinitialized ()
2026 && current_state->this_type.pc == type::SELF
2027 && current_state->this_type.equals (ct, this)
2028 // We don't look at the signature, figuring that if it is
2029 // wrong we will fail during linking. FIXME?
2030 && _Jv_Linker::has_field_p (current_class, name))
2031 // Note that we don't actually know whether we're going to match
2032 // against 'this' or some other object of the same type. So,
2033 // here we set things up so that it doesn't matter. This relies
2034 // on knowing what our caller is up to.
2035 class_type->set_uninitialized (type::EITHER, this);
2040 type check_method_constant (int index, bool is_interface,
2041 _Jv_Utf8Const **method_name,
2042 _Jv_Utf8Const **method_signature)
2044 return handle_field_or_method (index,
2046 ? JV_CONSTANT_InterfaceMethodref
2047 : JV_CONSTANT_Methodref),
2048 method_name, method_signature);
2051 type get_one_type (char *&p)
2069 _Jv_Utf8Const *name = make_utf8_const (start, p - start);
2070 return type (name, this);
2073 // Casting to jchar here is ok since we are looking at an ASCII
2075 type_val rt = get_type_val_for_signature (jchar (v));
2077 if (arraycount == 0)
2079 // Callers of this function eventually push their arguments on
2080 // the stack. So, promote them here.
2081 return type (rt).promote ();
2084 jclass k = construct_primitive_array_type (rt);
2085 while (--arraycount > 0)
2086 k = _Jv_GetArrayClass (k, NULL);
2087 return type (k, this);
2090 void compute_argument_types (_Jv_Utf8Const *signature,
2093 char *p = signature->chars();
2100 types[i++] = get_one_type (p);
2103 type compute_return_type (_Jv_Utf8Const *signature)
2105 char *p = signature->chars();
2109 return get_one_type (p);
2112 void check_return_type (type onstack)
2114 type rt = compute_return_type (current_method->self->signature);
2115 if (! rt.compatible (onstack, this))
2116 verify_fail ("incompatible return type");
2119 // Initialize the stack for the new method. Returns true if this
2120 // method is an instance initializer.
2121 bool initialize_stack ()
2124 bool is_init = _Jv_equalUtf8Consts (current_method->self->name,
2126 bool is_clinit = _Jv_equalUtf8Consts (current_method->self->name,
2129 using namespace java::lang::reflect;
2130 if (! Modifier::isStatic (current_method->self->accflags))
2132 type kurr (current_class, this);
2135 kurr.set_uninitialized (type::SELF, this);
2139 verify_fail ("<clinit> method must be static");
2140 set_variable (0, kurr);
2141 current_state->set_this_type (kurr);
2147 verify_fail ("<init> method must be non-static");
2150 // We have to handle wide arguments specially here.
2151 int arg_count = _Jv_count_arguments (current_method->self->signature);
2152 type arg_types[arg_count];
2153 compute_argument_types (current_method->self->signature, arg_types);
2154 for (int i = 0; i < arg_count; ++i)
2156 set_variable (var, arg_types[i]);
2158 if (arg_types[i].iswide ())
2165 void verify_instructions_0 ()
2167 current_state = new state (current_method->max_stack,
2168 current_method->max_locals);
2173 // True if we are verifying an instance initializer.
2174 bool this_is_init = initialize_stack ();
2176 states = (linked<state> **) _Jv_Malloc (sizeof (linked<state> *)
2177 * current_method->code_length);
2178 for (int i = 0; i < current_method->code_length; ++i)
2181 next_verify_state = NULL;
2185 // If the PC was invalidated, get a new one from the work list.
2186 if (PC == state::NO_NEXT)
2188 state *new_state = pop_jump ();
2189 // If it is null, we're done.
2190 if (new_state == NULL)
2193 PC = new_state->get_pc ();
2194 debug_print ("== State pop from pending list\n");
2195 // Set up the current state.
2196 current_state->copy (new_state, current_method->max_stack,
2197 current_method->max_locals);
2201 // We only have to do this checking in the situation where
2202 // control flow falls through from the previous
2203 // instruction. Otherwise merging is done at the time we
2204 // push the branch. Note that we'll catch the
2205 // off-the-end problem just below.
2206 if (PC < current_method->code_length && states[PC] != NULL)
2208 // We've already visited this instruction. So merge
2209 // the states together. It is simplest, but not most
2210 // efficient, to just always invalidate the PC here.
2211 merge_into (PC, current_state);
2217 // Control can't fall off the end of the bytecode. We need to
2218 // check this in both cases, not just the fall-through case,
2219 // because we don't check to see whether a `jsr' appears at
2220 // the end of the bytecode until we process a `ret'.
2221 if (PC >= current_method->code_length)
2222 verify_fail ("fell off end");
2224 // We only have to keep saved state at branch targets. If
2225 // we're at a branch target and the state here hasn't been set
2226 // yet, we set it now. You might notice that `ret' targets
2227 // won't necessarily have FLAG_BRANCH_TARGET set. This
2228 // doesn't matter, since those states will be filled in by
2230 if (states[PC] == NULL && (flags[PC] & FLAG_BRANCH_TARGET))
2231 add_new_state (PC, current_state);
2233 // Set this before handling exceptions so that debug output is
2237 // Update states for all active exception handlers. Ordinarily
2238 // there are not many exception handlers. So we simply run
2239 // through them all.
2240 for (int i = 0; i < current_method->exc_count; ++i)
2242 if (PC >= exception[i].start_pc.i && PC < exception[i].end_pc.i)
2244 type handler (&java::lang::Throwable::class$, this);
2245 if (exception[i].handler_type.i != 0)
2246 handler = check_class_constant (exception[i].handler_type.i);
2247 push_exception_jump (handler, exception[i].handler_pc.i);
2251 current_state->print (" ", PC, current_method->max_stack,
2252 current_method->max_locals);
2253 java_opcode opcode = (java_opcode) bytecode[PC++];
2259 case op_aconst_null:
2260 push_type (null_type);
2270 push_type (int_type);
2275 push_type (long_type);
2281 push_type (float_type);
2286 push_type (double_type);
2291 push_type (int_type);
2296 push_type (int_type);
2300 push_type (check_constant (get_byte ()));
2303 push_type (check_constant (get_ushort ()));
2306 push_type (check_wide_constant (get_ushort ()));
2310 push_type (get_variable (get_byte (), int_type));
2313 push_type (get_variable (get_byte (), long_type));
2316 push_type (get_variable (get_byte (), float_type));
2319 push_type (get_variable (get_byte (), double_type));
2322 push_type (get_variable (get_byte (), reference_type));
2329 push_type (get_variable (opcode - op_iload_0, int_type));
2335 push_type (get_variable (opcode - op_lload_0, long_type));
2341 push_type (get_variable (opcode - op_fload_0, float_type));
2347 push_type (get_variable (opcode - op_dload_0, double_type));
2353 push_type (get_variable (opcode - op_aload_0, reference_type));
2356 pop_type (int_type);
2357 push_type (require_array_type (pop_init_ref (reference_type),
2361 pop_type (int_type);
2362 push_type (require_array_type (pop_init_ref (reference_type),
2366 pop_type (int_type);
2367 push_type (require_array_type (pop_init_ref (reference_type),
2371 pop_type (int_type);
2372 push_type (require_array_type (pop_init_ref (reference_type),
2376 pop_type (int_type);
2377 push_type (require_array_type (pop_init_ref (reference_type),
2381 pop_type (int_type);
2382 require_array_type (pop_init_ref (reference_type), byte_type);
2383 push_type (int_type);
2386 pop_type (int_type);
2387 require_array_type (pop_init_ref (reference_type), char_type);
2388 push_type (int_type);
2391 pop_type (int_type);
2392 require_array_type (pop_init_ref (reference_type), short_type);
2393 push_type (int_type);
2396 set_variable (get_byte (), pop_type (int_type));
2399 set_variable (get_byte (), pop_type (long_type));
2402 set_variable (get_byte (), pop_type (float_type));
2405 set_variable (get_byte (), pop_type (double_type));
2408 set_variable (get_byte (), pop_ref_or_return ());
2414 set_variable (opcode - op_istore_0, pop_type (int_type));
2420 set_variable (opcode - op_lstore_0, pop_type (long_type));
2426 set_variable (opcode - op_fstore_0, pop_type (float_type));
2432 set_variable (opcode - op_dstore_0, pop_type (double_type));
2438 set_variable (opcode - op_astore_0, pop_ref_or_return ());
2441 pop_type (int_type);
2442 pop_type (int_type);
2443 require_array_type (pop_init_ref (reference_type), int_type);
2446 pop_type (long_type);
2447 pop_type (int_type);
2448 require_array_type (pop_init_ref (reference_type), long_type);
2451 pop_type (float_type);
2452 pop_type (int_type);
2453 require_array_type (pop_init_ref (reference_type), float_type);
2456 pop_type (double_type);
2457 pop_type (int_type);
2458 require_array_type (pop_init_ref (reference_type), double_type);
2461 pop_type (reference_type);
2462 pop_type (int_type);
2463 require_array_type (pop_init_ref (reference_type), reference_type);
2466 pop_type (int_type);
2467 pop_type (int_type);
2468 require_array_type (pop_init_ref (reference_type), byte_type);
2471 pop_type (int_type);
2472 pop_type (int_type);
2473 require_array_type (pop_init_ref (reference_type), char_type);
2476 pop_type (int_type);
2477 pop_type (int_type);
2478 require_array_type (pop_init_ref (reference_type), short_type);
2485 type t = pop_raw ();
2509 type t2 = pop_raw ();
2524 type t = pop_raw ();
2539 type t1 = pop_raw ();
2556 type t1 = pop_raw ();
2559 type t2 = pop_raw ();
2577 type t3 = pop_raw ();
2615 pop_type (int_type);
2616 push_type (pop_type (int_type));
2626 pop_type (long_type);
2627 push_type (pop_type (long_type));
2632 pop_type (int_type);
2633 push_type (pop_type (long_type));
2640 pop_type (float_type);
2641 push_type (pop_type (float_type));
2648 pop_type (double_type);
2649 push_type (pop_type (double_type));
2655 push_type (pop_type (int_type));
2658 push_type (pop_type (long_type));
2661 push_type (pop_type (float_type));
2664 push_type (pop_type (double_type));
2667 get_variable (get_byte (), int_type);
2671 pop_type (int_type);
2672 push_type (long_type);
2675 pop_type (int_type);
2676 push_type (float_type);
2679 pop_type (int_type);
2680 push_type (double_type);
2683 pop_type (long_type);
2684 push_type (int_type);
2687 pop_type (long_type);
2688 push_type (float_type);
2691 pop_type (long_type);
2692 push_type (double_type);
2695 pop_type (float_type);
2696 push_type (int_type);
2699 pop_type (float_type);
2700 push_type (long_type);
2703 pop_type (float_type);
2704 push_type (double_type);
2707 pop_type (double_type);
2708 push_type (int_type);
2711 pop_type (double_type);
2712 push_type (long_type);
2715 pop_type (double_type);
2716 push_type (float_type);
2719 pop_type (long_type);
2720 pop_type (long_type);
2721 push_type (int_type);
2725 pop_type (float_type);
2726 pop_type (float_type);
2727 push_type (int_type);
2731 pop_type (double_type);
2732 pop_type (double_type);
2733 push_type (int_type);
2741 pop_type (int_type);
2742 push_jump (get_short ());
2750 pop_type (int_type);
2751 pop_type (int_type);
2752 push_jump (get_short ());
2756 pop_type (reference_type);
2757 pop_type (reference_type);
2758 push_jump (get_short ());
2761 push_jump (get_short ());
2765 handle_jsr_insn (get_short ());
2768 handle_ret_insn (get_byte ());
2770 case op_tableswitch:
2772 pop_type (int_type);
2774 push_jump (get_int ());
2775 jint low = get_int ();
2776 jint high = get_int ();
2777 // Already checked LOW -vs- HIGH.
2778 for (int i = low; i <= high; ++i)
2779 push_jump (get_int ());
2784 case op_lookupswitch:
2786 pop_type (int_type);
2788 push_jump (get_int ());
2789 jint npairs = get_int ();
2790 // Already checked NPAIRS >= 0.
2792 for (int i = 0; i < npairs; ++i)
2794 jint key = get_int ();
2795 if (i > 0 && key <= lastkey)
2796 verify_fail ("lookupswitch pairs unsorted", start_PC);
2798 push_jump (get_int ());
2804 check_return_type (pop_type (int_type));
2808 check_return_type (pop_type (long_type));
2812 check_return_type (pop_type (float_type));
2816 check_return_type (pop_type (double_type));
2820 check_return_type (pop_init_ref (reference_type));
2824 // We only need to check this when the return type is
2825 // void, because all instance initializers return void.
2827 current_state->check_this_initialized (this);
2828 check_return_type (void_type);
2832 push_type (check_field_constant (get_ushort ()));
2835 pop_type (check_field_constant (get_ushort ()));
2840 type field = check_field_constant (get_ushort (), &klass);
2848 type field = check_field_constant (get_ushort (), &klass, true);
2854 case op_invokevirtual:
2855 case op_invokespecial:
2856 case op_invokestatic:
2857 case op_invokeinterface:
2859 _Jv_Utf8Const *method_name, *method_signature;
2861 = check_method_constant (get_ushort (),
2862 opcode == op_invokeinterface,
2865 // NARGS is only used when we're processing
2866 // invokeinterface. It is simplest for us to compute it
2867 // here and then verify it later.
2869 if (opcode == op_invokeinterface)
2871 nargs = get_byte ();
2872 if (get_byte () != 0)
2873 verify_fail ("invokeinterface dummy byte is wrong");
2876 bool is_init = false;
2877 if (_Jv_equalUtf8Consts (method_name, gcj::init_name))
2880 if (opcode != op_invokespecial)
2881 verify_fail ("can't invoke <init>");
2883 else if (method_name->first() == '<')
2884 verify_fail ("can't invoke method starting with `<'");
2886 // Pop arguments and check types.
2887 int arg_count = _Jv_count_arguments (method_signature);
2888 type arg_types[arg_count];
2889 compute_argument_types (method_signature, arg_types);
2890 for (int i = arg_count - 1; i >= 0; --i)
2892 // This is only used for verifying the byte for
2894 nargs -= arg_types[i].depth ();
2895 pop_init_ref (arg_types[i]);
2898 if (opcode == op_invokeinterface
2900 verify_fail ("wrong argument count for invokeinterface");
2902 if (opcode != op_invokestatic)
2904 type t = class_type;
2907 // In this case the PC doesn't matter.
2908 t.set_uninitialized (type::UNINIT, this);
2909 // FIXME: check to make sure that the <init>
2910 // call is to the right class.
2911 // It must either be super or an exact class
2914 type raw = pop_raw ();
2915 if (! t.compatible (raw, this))
2916 verify_fail ("incompatible type on stack");
2919 current_state->set_initialized (raw.get_pc (),
2920 current_method->max_locals);
2923 type rt = compute_return_type (method_signature);
2931 type t = check_class_constant (get_ushort ());
2933 verify_fail ("type is array");
2934 t.set_uninitialized (start_PC, this);
2941 int atype = get_byte ();
2942 // We intentionally have chosen constants to make this
2944 if (atype < boolean_type || atype > long_type)
2945 verify_fail ("type not primitive", start_PC);
2946 pop_type (int_type);
2947 type t (construct_primitive_array_type (type_val (atype)), this);
2952 pop_type (int_type);
2953 push_type (check_class_constant (get_ushort ()).to_array (this));
2955 case op_arraylength:
2957 type t = pop_init_ref (reference_type);
2958 if (! t.isarray () && ! t.isnull ())
2959 verify_fail ("array type expected");
2960 push_type (int_type);
2964 pop_type (type (&java::lang::Throwable::class$, this));
2968 pop_init_ref (reference_type);
2969 push_type (check_class_constant (get_ushort ()));
2972 pop_init_ref (reference_type);
2973 check_class_constant (get_ushort ());
2974 push_type (int_type);
2976 case op_monitorenter:
2977 pop_init_ref (reference_type);
2979 case op_monitorexit:
2980 pop_init_ref (reference_type);
2984 switch (get_byte ())
2987 push_type (get_variable (get_ushort (), int_type));
2990 push_type (get_variable (get_ushort (), long_type));
2993 push_type (get_variable (get_ushort (), float_type));
2996 push_type (get_variable (get_ushort (), double_type));
2999 push_type (get_variable (get_ushort (), reference_type));
3002 set_variable (get_ushort (), pop_type (int_type));
3005 set_variable (get_ushort (), pop_type (long_type));
3008 set_variable (get_ushort (), pop_type (float_type));
3011 set_variable (get_ushort (), pop_type (double_type));
3014 set_variable (get_ushort (), pop_init_ref (reference_type));
3017 handle_ret_insn (get_short ());
3020 get_variable (get_ushort (), int_type);
3024 verify_fail ("unrecognized wide instruction", start_PC);
3028 case op_multianewarray:
3030 type atype = check_class_constant (get_ushort ());
3031 int dim = get_byte ();
3033 verify_fail ("too few dimensions to multianewarray", start_PC);
3034 atype.verify_dimensions (dim, this);
3035 for (int i = 0; i < dim; ++i)
3036 pop_type (int_type);
3042 pop_type (reference_type);
3043 push_jump (get_short ());
3046 push_jump (get_int ());
3050 handle_jsr_insn (get_int ());
3053 // These are unused here, but we call them out explicitly
3054 // so that -Wswitch-enum doesn't complain.
3060 case op_putstatic_1:
3061 case op_putstatic_2:
3062 case op_putstatic_4:
3063 case op_putstatic_8:
3064 case op_putstatic_a:
3066 case op_getfield_2s:
3067 case op_getfield_2u:
3071 case op_getstatic_1:
3072 case op_getstatic_2s:
3073 case op_getstatic_2u:
3074 case op_getstatic_4:
3075 case op_getstatic_8:
3076 case op_getstatic_a:
3078 // Unrecognized opcode.
3079 verify_fail ("unrecognized instruction in verify_instructions_0",
3087 void verify_instructions ()
3090 verify_instructions_0 ();
3093 _Jv_BytecodeVerifier (_Jv_InterpMethod *m)
3095 // We just print the text as utf-8. This is just for debugging
3097 debug_print ("--------------------------------\n");
3098 debug_print ("-- Verifying method `%s'\n", m->self->name->chars());
3101 bytecode = m->bytecode ();
3102 exception = m->exceptions ();
3103 current_class = m->defining_class;
3111 ~_Jv_BytecodeVerifier ()
3116 while (utf8_list != NULL)
3118 linked<_Jv_Utf8Const> *n = utf8_list->next;
3119 _Jv_Free (utf8_list);
3123 while (isect_list != NULL)
3125 ref_intersection *next = isect_list->alloc_next;
3132 for (int i = 0; i < current_method->code_length; ++i)
3134 linked<state> *iter = states[i];
3135 while (iter != NULL)
3137 linked<state> *next = iter->next;
3149 _Jv_VerifyMethod (_Jv_InterpMethod *meth)
3151 _Jv_BytecodeVerifier v (meth);
3152 v.verify_instructions ();
3155 #endif /* INTERPRETER */