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>
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>
37 #endif /* VERIFY_DEBUG */
40 // This is used to mark states which are not scheduled for
42 #define INVALID_STATE ((state *) -1)
44 static void debug_print (const char *fmt, ...)
45 __attribute__ ((format (printf, 1, 2)));
48 debug_print (MAYBE_UNUSED const char *fmt, ...)
53 vfprintf (stderr, fmt, ap);
55 #endif /* VERIFY_DEBUG */
58 // This started as a fairly ordinary verifier, and for the most part
59 // it remains so. It works in the obvious way, by modeling the effect
60 // of each opcode as it is encountered. For most opcodes, this is a
61 // straightforward operation.
63 // This verifier does not do type merging. It used to, but this
64 // results in difficulty verifying some relatively simple code
65 // involving interfaces, and it pushed some verification work into the
68 // Instead of merging reference types, when we reach a point where two
69 // flows of control merge, we simply keep the union of reference types
70 // from each branch. Then, when we need to verify a fact about a
71 // reference on the stack (e.g., that it is compatible with the
72 // argument type of a method), we check to ensure that all possible
73 // types satisfy the requirement.
75 // Another area this verifier differs from the norm is in its handling
76 // of subroutines. The JVM specification has some confusing things to
77 // say about subroutines. For instance, it makes claims about not
78 // allowing subroutines to merge and it rejects recursive subroutines.
79 // For the most part these are red herrings; we used to try to follow
80 // these things but they lead to problems. For example, the notion of
81 // "being in a subroutine" is not well-defined: is an exception
82 // handler in a subroutine? If you never execute the `ret' but
83 // instead `goto 1' do you remain in the subroutine?
85 // For clarity on what is really required for type safety, read
86 // "Simple Verification Technique for Complex Java Bytecode
87 // Subroutines" by Alessandro Coglio. Among other things this paper
88 // shows that recursive subroutines are not harmful to type safety.
89 // We implement something similar to what he proposes. Note that this
90 // means that this verifier will accept code that is rejected by some
93 // For those not wanting to read the paper, the basic observation is
94 // that we can maintain split states in subroutines. We maintain one
95 // state for each calling `jsr'. In other words, we re-verify a
96 // subroutine once for each caller, using the exact types held by the
97 // callers (as opposed to the old approach of merging types and
98 // keeping a bitmap registering what did or did not change). This
99 // approach lets us continue to verify correctly even when a
100 // subroutine is exited via `goto' or `athrow' and not `ret'.
102 // In some other areas the JVM specification is (mildly) incorrect,
103 // but we still implement what is specified. For instance, you cannot
104 // violate type safety by allocating an object with `new' and then
105 // failing to initialize it, no matter how one branches or where one
106 // stores the uninitialized reference. See "Improving the official
107 // specification of Java bytecode verification" by Alessandro Coglio.
108 // Similarly, there's no real point in enforcing that padding bytes or
109 // the mystery byte of invokeinterface must be 0, but we do that too.
111 // The verifier is currently neither completely lazy nor eager when it
112 // comes to loading classes. It tries to represent types by name when
113 // possible, and then loads them when it needs to verify a fact about
114 // the type. Checking types by name is valid because we only use
115 // names which come from the current class' constant pool. Since all
116 // such names are looked up using the same class loader, there is no
117 // danger that we might be fooled into comparing different types with
120 // In the future we plan to allow for a completely lazy mode of
121 // operation, where the verifier will construct a list of type
122 // assertions to be checked later.
124 // Some test cases for the verifier live in the "verify" module of the
125 // Mauve test suite. However, some of these are presently
126 // (2004-01-20) believed to be incorrect. (More precisely the notion
127 // of "correct" is not well-defined, and this verifier differs from
128 // others while remaining type-safe.) Some other tests live in the
129 // libgcj test suite.
130 class _Jv_BytecodeVerifier
134 static const int FLAG_INSN_START = 1;
135 static const int FLAG_BRANCH_TARGET = 2;
140 struct ref_intersection;
151 // The PC corresponding to the start of the current instruction.
154 // The current state of the stack, locals, etc.
155 state *current_state;
157 // At each branch target we keep a linked list of all the states we
158 // can process at that point. We'll only have multiple states at a
159 // given PC if they both have different return-address types in the
160 // same stack or local slot. This array is indexed by PC and holds
161 // the list of all such states.
162 linked<state> **states;
164 // We keep a linked list of all the states which we must reverify.
165 // This is the head of the list.
166 state *next_verify_state;
168 // We keep some flags for each instruction. The values are the
169 // FLAG_* constants defined above. This is an array indexed by PC.
172 // The bytecode itself.
173 unsigned char *bytecode;
175 _Jv_InterpException *exception;
178 jclass current_class;
180 _Jv_InterpMethod *current_method;
182 // A linked list of utf8 objects we allocate. This is really ugly,
183 // but without this our utf8 objects would be collected.
184 linked<_Jv_Utf8Const> *utf8_list;
186 // A linked list of all ref_intersection objects we allocate.
187 ref_intersection *isect_list;
189 // Create a new Utf-8 constant and return it. We do this to avoid
190 // having our Utf-8 constants prematurely collected. FIXME this is
192 _Jv_Utf8Const *make_utf8_const (char *s, int len)
194 _Jv_Utf8Const *val = _Jv_makeUtf8Const (s, len);
195 _Jv_Utf8Const *r = (_Jv_Utf8Const *) _Jv_Malloc (sizeof (_Jv_Utf8Const)
198 r->length = val->length;
200 memcpy (r->data, val->data, val->length + 1);
202 linked<_Jv_Utf8Const> *lu
203 = (linked<_Jv_Utf8Const> *) _Jv_Malloc (sizeof (linked<_Jv_Utf8Const>));
205 lu->next = utf8_list;
211 __attribute__ ((__noreturn__)) void verify_fail (char *s, jint pc = -1)
213 using namespace java::lang;
214 StringBuffer *buf = new StringBuffer ();
216 buf->append (JvNewStringLatin1 ("verification failed"));
221 buf->append (JvNewStringLatin1 (" at PC "));
225 _Jv_InterpMethod *method = current_method;
226 buf->append (JvNewStringLatin1 (" in "));
227 buf->append (current_class->getName());
228 buf->append ((jchar) ':');
229 buf->append (JvNewStringUTF (method->get_method()->name->data));
230 buf->append ((jchar) '(');
231 buf->append (JvNewStringUTF (method->get_method()->signature->data));
232 buf->append ((jchar) ')');
234 buf->append (JvNewStringLatin1 (": "));
235 buf->append (JvNewStringLatin1 (s));
236 throw new java::lang::VerifyError (buf->toString ());
239 // This enum holds a list of tags for all the different types we
240 // need to handle. Reference types are treated specially by the
246 // The values for primitive types are chosen to correspond to values
247 // specified to newarray.
257 // Used when overwriting second word of a double or long in the
258 // local variables. Also used after merging local variable states
259 // to indicate an unusable value.
262 // This is the second word of a two-word value, i.e., a double or
266 // Everything after `reference_type' must be a reference type.
269 uninitialized_reference_type
272 // This represents a merged class type. Some verifiers (including
273 // earlier versions of this one) will compute the intersection of
274 // two class types when merging states. However, this loses
275 // critical information about interfaces implemented by the various
276 // classes. So instead we keep track of all the actual classes that
278 struct ref_intersection
280 // Whether or not this type has been resolved.
286 // For a resolved reference type, this is a pointer to the class.
288 // For other reference types, this it the name of the class.
292 // Link to the next reference in the intersection.
293 ref_intersection *ref_next;
295 // This is used to keep track of all the allocated
296 // ref_intersection objects, so we can free them.
297 // FIXME: we should allocate these in chunks.
298 ref_intersection *alloc_next;
300 ref_intersection (jclass klass, _Jv_BytecodeVerifier *verifier)
305 alloc_next = verifier->isect_list;
306 verifier->isect_list = this;
309 ref_intersection (_Jv_Utf8Const *name, _Jv_BytecodeVerifier *verifier)
314 alloc_next = verifier->isect_list;
315 verifier->isect_list = this;
318 ref_intersection (ref_intersection *dup, ref_intersection *tail,
319 _Jv_BytecodeVerifier *verifier)
322 is_resolved = dup->is_resolved;
324 alloc_next = verifier->isect_list;
325 verifier->isect_list = this;
328 bool equals (ref_intersection *other, _Jv_BytecodeVerifier *verifier)
330 if (! is_resolved && ! other->is_resolved
331 && _Jv_equalUtf8Consts (data.name, other->data.name))
335 if (! other->is_resolved)
336 other->resolve (verifier);
337 return data.klass == other->data.klass;
340 // Merge THIS type into OTHER, returning the result. This will
341 // return OTHER if all the classes in THIS already appear in
343 ref_intersection *merge (ref_intersection *other,
344 _Jv_BytecodeVerifier *verifier)
346 ref_intersection *tail = other;
347 for (ref_intersection *self = this; self != NULL; self = self->ref_next)
350 for (ref_intersection *iter = other; iter != NULL;
351 iter = iter->ref_next)
353 if (iter->equals (self, verifier))
361 tail = new ref_intersection (self, tail, verifier);
366 void resolve (_Jv_BytecodeVerifier *verifier)
371 using namespace java::lang;
372 java::lang::ClassLoader *loader
373 = verifier->current_class->getClassLoaderInternal();
374 // We might see either kind of name. Sigh.
375 if (data.name->data[0] == 'L'
376 && data.name->data[data.name->length - 1] == ';')
377 data.klass = _Jv_FindClassFromSignature (data.name->data, loader);
379 data.klass = Class::forName (_Jv_NewStringUtf8Const (data.name),
384 // See if an object of type OTHER can be assigned to an object of
385 // type *THIS. This might resolve classes in one chain or the
387 bool compatible (ref_intersection *other,
388 _Jv_BytecodeVerifier *verifier)
390 ref_intersection *self = this;
392 for (; self != NULL; self = self->ref_next)
394 ref_intersection *other_iter = other;
396 for (; other_iter != NULL; other_iter = other_iter->ref_next)
398 // Avoid resolving if possible.
399 if (! self->is_resolved
400 && ! other_iter->is_resolved
401 && _Jv_equalUtf8Consts (self->data.name,
402 other_iter->data.name))
405 if (! self->is_resolved)
406 self->resolve(verifier);
407 if (! other_iter->is_resolved)
408 other_iter->resolve(verifier);
410 if (! is_assignable_from_slow (self->data.klass,
411 other_iter->data.klass))
421 // assert (ref_next == NULL);
423 return data.klass->isArray ();
425 return data.name->data[0] == '[';
428 bool isinterface (_Jv_BytecodeVerifier *verifier)
430 // assert (ref_next == NULL);
433 return data.klass->isInterface ();
436 bool isabstract (_Jv_BytecodeVerifier *verifier)
438 // assert (ref_next == NULL);
441 using namespace java::lang::reflect;
442 return Modifier::isAbstract (data.klass->getModifiers ());
445 jclass getclass (_Jv_BytecodeVerifier *verifier)
452 int count_dimensions ()
457 jclass k = data.klass;
458 while (k->isArray ())
460 k = k->getComponentType ();
466 char *p = data.name->data;
473 void *operator new (size_t bytes)
475 return _Jv_Malloc (bytes);
478 void operator delete (void *mem)
484 // Return the type_val corresponding to a primitive signature
485 // character. For instance `I' returns `int.class'.
486 type_val get_type_val_for_signature (jchar sig)
519 verify_fail ("invalid signature");
524 // Return the type_val corresponding to a primitive class.
525 type_val get_type_val_for_signature (jclass k)
527 return get_type_val_for_signature ((jchar) k->method_count);
530 // This is like _Jv_IsAssignableFrom, but it works even if SOURCE or
531 // TARGET haven't been prepared.
532 static bool is_assignable_from_slow (jclass target, jclass source)
534 // First, strip arrays.
535 while (target->isArray ())
537 // If target is array, source must be as well.
538 if (! source->isArray ())
540 target = target->getComponentType ();
541 source = source->getComponentType ();
545 if (target == &java::lang::Object::class$)
550 if (source == target)
553 if (target->isPrimitive () || source->isPrimitive ())
556 if (target->isInterface ())
558 for (int i = 0; i < source->interface_count; ++i)
560 // We use a recursive call because we also need to
561 // check superinterfaces.
562 if (is_assignable_from_slow (target, source->interfaces[i]))
566 source = source->getSuperclass ();
568 while (source != NULL);
573 // The `type' class is used to represent a single type in the
580 // For reference types, the representation of the type.
581 ref_intersection *klass;
583 // This is used in two situations.
585 // First, when constructing a new object, it is the PC of the
586 // `new' instruction which created the object. We use the special
587 // value UNINIT to mean that this is uninitialized, and the
588 // special value SELF for the case where the current method is
589 // itself the <init> method.
591 // Second, when the key is return_address_type, this holds the PC
592 // of the instruction following the `jsr'.
595 static const int UNINIT = -2;
596 static const int SELF = -1;
598 // Basic constructor.
601 key = unsuitable_type;
606 // Make a new instance given the type tag. We assume a generic
607 // `reference_type' means Object.
611 // For reference_type, if KLASS==NULL then that means we are
612 // looking for a generic object of any kind, including an
613 // uninitialized reference.
618 // Make a new instance given a class.
619 type (jclass k, _Jv_BytecodeVerifier *verifier)
621 key = reference_type;
622 klass = new ref_intersection (k, verifier);
626 // Make a new instance given the name of a class.
627 type (_Jv_Utf8Const *n, _Jv_BytecodeVerifier *verifier)
629 key = reference_type;
630 klass = new ref_intersection (n, verifier);
642 // These operators are required because libgcj can't link in
644 void *operator new[] (size_t bytes)
646 return _Jv_Malloc (bytes);
649 void operator delete[] (void *mem)
654 type& operator= (type_val k)
662 type& operator= (const type& t)
670 // Promote a numeric type.
673 if (key == boolean_type || key == char_type
674 || key == byte_type || key == short_type)
679 // Mark this type as the uninitialized result of `new'.
680 void set_uninitialized (int npc, _Jv_BytecodeVerifier *verifier)
682 if (key == reference_type)
683 key = uninitialized_reference_type;
685 verifier->verify_fail ("internal error in type::uninitialized");
689 // Mark this type as now initialized.
690 void set_initialized (int npc)
692 if (npc != UNINIT && pc == npc && key == uninitialized_reference_type)
694 key = reference_type;
699 // Mark this type as a particular return address.
700 void set_return_address (int npc)
705 // Return true if this type and type OTHER are considered
706 // mergeable for the purposes of state merging. This is related
707 // to subroutine handling. For this purpose two types are
708 // considered unmergeable if they are both return-addresses but
709 // have different PCs.
710 bool state_mergeable_p (const type &other) const
712 return (key != return_address_type
713 || other.key != return_address_type
717 // Return true if an object of type K can be assigned to a variable
718 // of type *THIS. Handle various special cases too. Might modify
719 // *THIS or K. Note however that this does not perform numeric
721 bool compatible (type &k, _Jv_BytecodeVerifier *verifier)
723 // Any type is compatible with the unsuitable type.
724 if (key == unsuitable_type)
727 if (key < reference_type || k.key < reference_type)
730 // The `null' type is convertible to any initialized reference
732 if (key == null_type)
733 return k.key != uninitialized_reference_type;
734 if (k.key == null_type)
735 return key != uninitialized_reference_type;
737 // A special case for a generic reference.
741 verifier->verify_fail ("programmer error in type::compatible");
743 // An initialized type and an uninitialized type are not
745 if (isinitialized () != k.isinitialized ())
748 // Two uninitialized objects are compatible if either:
749 // * The PCs are identical, or
750 // * One PC is UNINIT.
751 if (! isinitialized ())
753 if (pc != k.pc && pc != UNINIT && k.pc != UNINIT)
757 return klass->compatible(k.klass, verifier);
762 return key == void_type;
767 return key == long_type || key == double_type;
770 // Return number of stack or local variable slots taken by this
774 return iswide () ? 2 : 1;
777 bool isarray () const
779 // We treat null_type as not an array. This is ok based on the
780 // current uses of this method.
781 if (key == reference_type)
782 return klass->isarray ();
788 return key == null_type;
791 bool isinterface (_Jv_BytecodeVerifier *verifier)
793 if (key != reference_type)
795 return klass->isinterface (verifier);
798 bool isabstract (_Jv_BytecodeVerifier *verifier)
800 if (key != reference_type)
802 return klass->isabstract (verifier);
805 // Return the element type of an array.
806 type element_type (_Jv_BytecodeVerifier *verifier)
808 if (key != reference_type)
809 verifier->verify_fail ("programmer error in type::element_type()", -1);
811 jclass k = klass->getclass (verifier)->getComponentType ();
812 if (k->isPrimitive ())
813 return type (verifier->get_type_val_for_signature (k));
814 return type (k, verifier);
817 // Return the array type corresponding to an initialized
818 // reference. We could expand this to work for other kinds of
819 // types, but currently we don't need to.
820 type to_array (_Jv_BytecodeVerifier *verifier)
822 if (key != reference_type)
823 verifier->verify_fail ("internal error in type::to_array()");
825 jclass k = klass->getclass (verifier);
826 return type (_Jv_GetArrayClass (k, k->getClassLoaderInternal()),
830 bool isreference () const
832 return key >= reference_type;
840 bool isinitialized () const
842 return key == reference_type || key == null_type;
845 bool isresolved () const
847 return (key == reference_type
849 || key == uninitialized_reference_type);
852 void verify_dimensions (int ndims, _Jv_BytecodeVerifier *verifier)
854 // The way this is written, we don't need to check isarray().
855 if (key != reference_type)
856 verifier->verify_fail ("internal error in verify_dimensions:"
857 " not a reference type");
859 if (klass->count_dimensions () < ndims)
860 verifier->verify_fail ("array type has fewer dimensions"
864 // Merge OLD_TYPE into this. On error throw exception. Return
865 // true if the merge caused a type change.
866 bool merge (type& old_type, bool local_semantics,
867 _Jv_BytecodeVerifier *verifier)
869 bool changed = false;
870 bool refo = old_type.isreference ();
871 bool refn = isreference ();
874 if (old_type.key == null_type)
876 else if (key == null_type)
881 else if (isinitialized () != old_type.isinitialized ())
882 verifier->verify_fail ("merging initialized and uninitialized types");
885 if (! isinitialized ())
889 else if (old_type.pc == UNINIT)
891 else if (pc != old_type.pc)
892 verifier->verify_fail ("merging different uninitialized types");
895 ref_intersection *merged = old_type.klass->merge (klass,
904 else if (refo || refn || key != old_type.key)
908 // If we already have an `unsuitable' type, then we
909 // don't need to change again.
910 if (key != unsuitable_type)
912 key = unsuitable_type;
917 verifier->verify_fail ("unmergeable type");
923 void print (void) const
928 case boolean_type: c = 'Z'; break;
929 case byte_type: c = 'B'; break;
930 case char_type: c = 'C'; break;
931 case short_type: c = 'S'; break;
932 case int_type: c = 'I'; break;
933 case long_type: c = 'J'; break;
934 case float_type: c = 'F'; break;
935 case double_type: c = 'D'; break;
936 case void_type: c = 'V'; break;
937 case unsuitable_type: c = '-'; break;
938 case return_address_type: c = 'r'; break;
939 case continuation_type: c = '+'; break;
940 case reference_type: c = 'L'; break;
941 case null_type: c = '@'; break;
942 case uninitialized_reference_type: c = 'U'; break;
944 debug_print ("%c", c);
946 #endif /* VERIFY_DEBUG */
949 // This class holds all the state information we need for a given
953 // The current top of the stack, in terms of slots.
955 // The current depth of the stack. This will be larger than
956 // STACKTOP when wide types are on the stack.
960 // The local variables.
962 // We keep track of the type of `this' specially. This is used to
963 // ensure that an instance initializer invokes another initializer
964 // on `this' before returning. We must keep track of this
965 // specially because otherwise we might be confused by code which
966 // assigns to locals[0] (overwriting `this') and then returns
967 // without really initializing.
970 // The PC for this state. This is only valid on states which are
971 // permanently attached to a given PC. For an object like
972 // `current_state', which is used transiently, this has no
975 // We keep a linked list of all states requiring reverification.
976 // If this is the special value INVALID_STATE then this state is
977 // not on the list. NULL marks the end of the linked list.
980 // NO_NEXT is the PC value meaning that a new state must be
981 // acquired from the verification list.
982 static const int NO_NEXT = -1;
989 next = INVALID_STATE;
992 state (int max_stack, int max_locals)
997 stack = new type[max_stack];
998 for (int i = 0; i < max_stack; ++i)
999 stack[i] = unsuitable_type;
1000 locals = new type[max_locals];
1001 for (int i = 0; i < max_locals; ++i)
1002 locals[i] = unsuitable_type;
1004 next = INVALID_STATE;
1007 state (const state *orig, int max_stack, int max_locals)
1009 stack = new type[max_stack];
1010 locals = new type[max_locals];
1011 copy (orig, max_stack, max_locals);
1013 next = INVALID_STATE;
1024 void *operator new[] (size_t bytes)
1026 return _Jv_Malloc (bytes);
1029 void operator delete[] (void *mem)
1034 void *operator new (size_t bytes)
1036 return _Jv_Malloc (bytes);
1039 void operator delete (void *mem)
1044 void copy (const state *copy, int max_stack, int max_locals)
1046 stacktop = copy->stacktop;
1047 stackdepth = copy->stackdepth;
1048 for (int i = 0; i < max_stack; ++i)
1049 stack[i] = copy->stack[i];
1050 for (int i = 0; i < max_locals; ++i)
1051 locals[i] = copy->locals[i];
1053 this_type = copy->this_type;
1054 // Don't modify `next' or `pc'.
1057 // Modify this state to reflect entry to an exception handler.
1058 void set_exception (type t, int max_stack)
1063 for (int i = stacktop; i < max_stack; ++i)
1064 stack[i] = unsuitable_type;
1067 inline int get_pc () const
1072 void set_pc (int npc)
1077 // Merge STATE_OLD into this state. Destructively modifies this
1078 // state. Returns true if the new state was in fact changed.
1079 // Will throw an exception if the states are not mergeable.
1080 bool merge (state *state_old, int max_locals,
1081 _Jv_BytecodeVerifier *verifier)
1083 bool changed = false;
1085 // Special handling for `this'. If one or the other is
1086 // uninitialized, then the merge is uninitialized.
1087 if (this_type.isinitialized ())
1088 this_type = state_old->this_type;
1091 if (state_old->stacktop != stacktop) // FIXME stackdepth instead?
1092 verifier->verify_fail ("stack sizes differ");
1093 for (int i = 0; i < state_old->stacktop; ++i)
1095 if (stack[i].merge (state_old->stack[i], false, verifier))
1099 // Merge local variables.
1100 for (int i = 0; i < max_locals; ++i)
1102 if (locals[i].merge (state_old->locals[i], true, verifier))
1109 // Throw an exception if there is an uninitialized object on the
1110 // stack or in a local variable. EXCEPTION_SEMANTICS controls
1111 // whether we're using backwards-branch or exception-handing
1113 void check_no_uninitialized_objects (int max_locals,
1114 _Jv_BytecodeVerifier *verifier,
1115 bool exception_semantics = false)
1117 if (! exception_semantics)
1119 for (int i = 0; i < stacktop; ++i)
1120 if (stack[i].isreference () && ! stack[i].isinitialized ())
1121 verifier->verify_fail ("uninitialized object on stack");
1124 for (int i = 0; i < max_locals; ++i)
1125 if (locals[i].isreference () && ! locals[i].isinitialized ())
1126 verifier->verify_fail ("uninitialized object in local variable");
1128 check_this_initialized (verifier);
1131 // Ensure that `this' has been initialized.
1132 void check_this_initialized (_Jv_BytecodeVerifier *verifier)
1134 if (this_type.isreference () && ! this_type.isinitialized ())
1135 verifier->verify_fail ("`this' is uninitialized");
1138 // Set type of `this'.
1139 void set_this_type (const type &k)
1144 // Mark each `new'd object we know of that was allocated at PC as
1146 void set_initialized (int pc, int max_locals)
1148 for (int i = 0; i < stacktop; ++i)
1149 stack[i].set_initialized (pc);
1150 for (int i = 0; i < max_locals; ++i)
1151 locals[i].set_initialized (pc);
1152 this_type.set_initialized (pc);
1155 // This tests to see whether two states can be considered "merge
1156 // compatible". If both states have a return-address in the same
1157 // slot, and the return addresses are different, then they are not
1158 // compatible and we must not try to merge them.
1159 bool state_mergeable_p (state *other, int max_locals,
1160 _Jv_BytecodeVerifier *verifier)
1162 // This is tricky: if the stack sizes differ, then not only are
1163 // these not mergeable, but in fact we should give an error, as
1164 // we've found two execution paths that reach a branch target
1165 // with different stack depths. FIXME stackdepth instead?
1166 if (stacktop != other->stacktop)
1167 verifier->verify_fail ("stack sizes differ");
1169 for (int i = 0; i < stacktop; ++i)
1170 if (! stack[i].state_mergeable_p (other->stack[i]))
1172 for (int i = 0; i < max_locals; ++i)
1173 if (! locals[i].state_mergeable_p (other->locals[i]))
1178 void reverify (_Jv_BytecodeVerifier *verifier)
1180 if (next == INVALID_STATE)
1182 next = verifier->next_verify_state;
1183 verifier->next_verify_state = this;
1188 void print (const char *leader, int pc,
1189 int max_stack, int max_locals) const
1191 debug_print ("%s [%4d]: [stack] ", leader, pc);
1193 for (i = 0; i < stacktop; ++i)
1195 for (; i < max_stack; ++i)
1197 debug_print (" [local] ");
1198 for (i = 0; i < max_locals; ++i)
1200 debug_print (" | %p\n", this);
1203 inline void print (const char *, int, int, int) const
1206 #endif /* VERIFY_DEBUG */
1211 if (current_state->stacktop <= 0)
1212 verify_fail ("stack empty");
1213 type r = current_state->stack[--current_state->stacktop];
1214 current_state->stackdepth -= r.depth ();
1215 if (current_state->stackdepth < 0)
1216 verify_fail ("stack empty", start_PC);
1222 type r = pop_raw ();
1224 verify_fail ("narrow pop of wide type");
1228 type pop_type (type match)
1231 type t = pop_raw ();
1232 if (! match.compatible (t, this))
1233 verify_fail ("incompatible type on stack");
1237 // Pop a reference which is guaranteed to be initialized. MATCH
1238 // doesn't have to be a reference type; in this case this acts like
1240 type pop_init_ref (type match)
1242 type t = pop_raw ();
1243 if (t.isreference () && ! t.isinitialized ())
1244 verify_fail ("initialized reference required");
1245 else if (! match.compatible (t, this))
1246 verify_fail ("incompatible type on stack");
1250 // Pop a reference type or a return address.
1251 type pop_ref_or_return ()
1253 type t = pop_raw ();
1254 if (! t.isreference () && t.key != return_address_type)
1255 verify_fail ("expected reference or return address on stack");
1259 void push_type (type t)
1261 // If T is a numeric type like short, promote it to int.
1264 int depth = t.depth ();
1265 if (current_state->stackdepth + depth > current_method->max_stack)
1266 verify_fail ("stack overflow");
1267 current_state->stack[current_state->stacktop++] = t;
1268 current_state->stackdepth += depth;
1271 void set_variable (int index, type t)
1273 // If T is a numeric type like short, promote it to int.
1276 int depth = t.depth ();
1277 if (index > current_method->max_locals - depth)
1278 verify_fail ("invalid local variable");
1279 current_state->locals[index] = t;
1282 current_state->locals[index + 1] = continuation_type;
1283 if (index > 0 && current_state->locals[index - 1].iswide ())
1284 current_state->locals[index - 1] = unsuitable_type;
1287 type get_variable (int index, type t)
1289 int depth = t.depth ();
1290 if (index > current_method->max_locals - depth)
1291 verify_fail ("invalid local variable");
1292 if (! t.compatible (current_state->locals[index], this))
1293 verify_fail ("incompatible type in local variable");
1296 type t (continuation_type);
1297 if (! current_state->locals[index + 1].compatible (t, this))
1298 verify_fail ("invalid local variable");
1300 return current_state->locals[index];
1303 // Make sure ARRAY is an array type and that its elements are
1304 // compatible with type ELEMENT. Returns the actual element type.
1305 type require_array_type (type array, type element)
1307 // An odd case. Here we just pretend that everything went ok. If
1308 // the requested element type is some kind of reference, return
1309 // the null type instead.
1310 if (array.isnull ())
1311 return element.isreference () ? type (null_type) : element;
1313 if (! array.isarray ())
1314 verify_fail ("array required");
1316 type t = array.element_type (this);
1317 if (! element.compatible (t, this))
1319 // Special case for byte arrays, which must also be boolean
1322 if (element.key == byte_type)
1324 type e2 (boolean_type);
1325 ok = e2.compatible (t, this);
1328 verify_fail ("incompatible array element type");
1331 // Return T and not ELEMENT, because T might be specialized.
1337 if (PC >= current_method->code_length)
1338 verify_fail ("premature end of bytecode");
1339 return (jint) bytecode[PC++] & 0xff;
1344 jint b1 = get_byte ();
1345 jint b2 = get_byte ();
1346 return (jint) ((b1 << 8) | b2) & 0xffff;
1351 jint b1 = get_byte ();
1352 jint b2 = get_byte ();
1353 jshort s = (b1 << 8) | b2;
1359 jint b1 = get_byte ();
1360 jint b2 = get_byte ();
1361 jint b3 = get_byte ();
1362 jint b4 = get_byte ();
1363 return (b1 << 24) | (b2 << 16) | (b3 << 8) | b4;
1366 int compute_jump (int offset)
1368 int npc = start_PC + offset;
1369 if (npc < 0 || npc >= current_method->code_length)
1370 verify_fail ("branch out of range", start_PC);
1374 // Add a new state to the state list at NPC.
1375 state *add_new_state (int npc, state *old_state)
1377 state *new_state = new state (old_state, current_method->max_stack,
1378 current_method->max_locals);
1379 debug_print ("== New state in add_new_state\n");
1380 new_state->print ("New", npc, current_method->max_stack,
1381 current_method->max_locals);
1382 linked<state> *nlink
1383 = (linked<state> *) _Jv_Malloc (sizeof (linked<state>));
1384 nlink->val = new_state;
1385 nlink->next = states[npc];
1386 states[npc] = nlink;
1387 new_state->set_pc (npc);
1391 // Merge the indicated state into the state at the branch target and
1392 // schedule a new PC if there is a change. NPC is the PC of the
1393 // branch target, and FROM_STATE is the state at the source of the
1394 // branch. This method returns true if the destination state
1395 // changed and requires reverification, false otherwise.
1396 void merge_into (int npc, state *from_state)
1398 // Iterate over all target states and merge our state into each,
1399 // if applicable. FIXME one improvement we could make here is
1400 // "state destruction". Merging a new state into an existing one
1401 // might cause a return_address_type to be merged to
1402 // unsuitable_type. In this case the resulting state may now be
1403 // mergeable with other states currently held in parallel at this
1404 // location. So in this situation we could pairwise compare and
1405 // reduce the number of parallel states.
1406 bool applicable = false;
1407 for (linked<state> *iter = states[npc]; iter != NULL; iter = iter->next)
1409 state *new_state = iter->val;
1410 if (new_state->state_mergeable_p (from_state,
1411 current_method->max_locals, this))
1415 debug_print ("== Merge states in merge_into\n");
1416 from_state->print ("Frm", start_PC, current_method->max_stack,
1417 current_method->max_locals);
1418 new_state->print (" To", npc, current_method->max_stack,
1419 current_method->max_locals);
1420 bool changed = new_state->merge (from_state,
1421 current_method->max_locals,
1423 new_state->print ("New", npc, current_method->max_stack,
1424 current_method->max_locals);
1427 new_state->reverify (this);
1433 // Either we don't yet have a state at NPC, or we have a
1434 // return-address type that is in conflict with all existing
1435 // state. So, we need to create a new entry.
1436 state *new_state = add_new_state (npc, from_state);
1437 // A new state added in this way must always be reverified.
1438 new_state->reverify (this);
1442 void push_jump (int offset)
1444 int npc = compute_jump (offset);
1446 current_state->check_no_uninitialized_objects (current_method->max_locals, this);
1447 merge_into (npc, current_state);
1450 void push_exception_jump (type t, int pc)
1452 current_state->check_no_uninitialized_objects (current_method->max_locals,
1454 state s (current_state, current_method->max_stack,
1455 current_method->max_locals);
1456 if (current_method->max_stack < 1)
1457 verify_fail ("stack overflow at exception handler");
1458 s.set_exception (t, current_method->max_stack);
1459 merge_into (pc, &s);
1464 state *new_state = next_verify_state;
1465 if (new_state == INVALID_STATE)
1466 verify_fail ("programmer error in pop_jump");
1467 if (new_state != NULL)
1469 next_verify_state = new_state->next;
1470 new_state->next = INVALID_STATE;
1475 void invalidate_pc ()
1477 PC = state::NO_NEXT;
1480 void note_branch_target (int pc)
1482 // Don't check `pc <= PC', because we've advanced PC after
1483 // fetching the target and we haven't yet checked the next
1485 if (pc < PC && ! (flags[pc] & FLAG_INSN_START))
1486 verify_fail ("branch not to instruction start", start_PC);
1487 flags[pc] |= FLAG_BRANCH_TARGET;
1490 void skip_padding ()
1492 while ((PC % 4) > 0)
1493 if (get_byte () != 0)
1494 verify_fail ("found nonzero padding byte");
1497 // Do the work for a `ret' instruction. INDEX is the index into the
1499 void handle_ret_insn (int index)
1501 type ret_addr = get_variable (index, return_address_type);
1502 // It would be nice if we could do this. However, the JVM Spec
1503 // doesn't say that this is what happens. It is implied that
1504 // reusing a return address is invalid, but there's no actual
1505 // prohibition against it.
1506 // set_variable (index, unsuitable_type);
1508 int npc = ret_addr.get_pc ();
1509 // We might be returning to a `jsr' that is at the end of the
1510 // bytecode. This is ok if we never return from the called
1511 // subroutine, but if we see this here it is an error.
1512 if (npc >= current_method->code_length)
1513 verify_fail ("fell off end");
1516 current_state->check_no_uninitialized_objects (current_method->max_locals,
1518 merge_into (npc, current_state);
1522 void handle_jsr_insn (int offset)
1524 int npc = compute_jump (offset);
1527 current_state->check_no_uninitialized_objects (current_method->max_locals, this);
1529 // Modify our state as appropriate for entry into a subroutine.
1530 type ret_addr (return_address_type);
1531 ret_addr.set_return_address (PC);
1532 push_type (ret_addr);
1533 merge_into (npc, current_state);
1537 jclass construct_primitive_array_type (type_val prim)
1543 k = JvPrimClass (boolean);
1546 k = JvPrimClass (char);
1549 k = JvPrimClass (float);
1552 k = JvPrimClass (double);
1555 k = JvPrimClass (byte);
1558 k = JvPrimClass (short);
1561 k = JvPrimClass (int);
1564 k = JvPrimClass (long);
1567 // These aren't used here but we call them out to avoid
1570 case unsuitable_type:
1571 case return_address_type:
1572 case continuation_type:
1573 case reference_type:
1575 case uninitialized_reference_type:
1577 verify_fail ("unknown type in construct_primitive_array_type");
1579 k = _Jv_GetArrayClass (k, NULL);
1583 // This pass computes the location of branch targets and also
1584 // instruction starts.
1585 void branch_prepass ()
1587 flags = (char *) _Jv_Malloc (current_method->code_length);
1589 for (int i = 0; i < current_method->code_length; ++i)
1593 while (PC < current_method->code_length)
1595 // Set `start_PC' early so that error checking can have the
1598 flags[PC] |= FLAG_INSN_START;
1600 java_opcode opcode = (java_opcode) bytecode[PC++];
1604 case op_aconst_null:
1740 case op_monitorenter:
1741 case op_monitorexit:
1749 case op_arraylength:
1781 case op_invokespecial:
1782 case op_invokestatic:
1783 case op_invokevirtual:
1787 case op_multianewarray:
1810 note_branch_target (compute_jump (get_short ()));
1813 case op_tableswitch:
1816 note_branch_target (compute_jump (get_int ()));
1817 jint low = get_int ();
1818 jint hi = get_int ();
1820 verify_fail ("invalid tableswitch", start_PC);
1821 for (int i = low; i <= hi; ++i)
1822 note_branch_target (compute_jump (get_int ()));
1826 case op_lookupswitch:
1829 note_branch_target (compute_jump (get_int ()));
1830 int npairs = get_int ();
1832 verify_fail ("too few pairs in lookupswitch", start_PC);
1833 while (npairs-- > 0)
1836 note_branch_target (compute_jump (get_int ()));
1841 case op_invokeinterface:
1849 opcode = (java_opcode) get_byte ();
1851 if (opcode == op_iinc)
1858 note_branch_target (compute_jump (get_int ()));
1861 // These are unused here, but we call them out explicitly
1862 // so that -Wswitch-enum doesn't complain.
1868 case op_putstatic_1:
1869 case op_putstatic_2:
1870 case op_putstatic_4:
1871 case op_putstatic_8:
1872 case op_putstatic_a:
1874 case op_getfield_2s:
1875 case op_getfield_2u:
1879 case op_getstatic_1:
1880 case op_getstatic_2s:
1881 case op_getstatic_2u:
1882 case op_getstatic_4:
1883 case op_getstatic_8:
1884 case op_getstatic_a:
1886 verify_fail ("unrecognized instruction in branch_prepass",
1890 // See if any previous branch tried to branch to the middle of
1891 // this instruction.
1892 for (int pc = start_PC + 1; pc < PC; ++pc)
1894 if ((flags[pc] & FLAG_BRANCH_TARGET))
1895 verify_fail ("branch to middle of instruction", pc);
1899 // Verify exception handlers.
1900 for (int i = 0; i < current_method->exc_count; ++i)
1902 if (! (flags[exception[i].handler_pc.i] & FLAG_INSN_START))
1903 verify_fail ("exception handler not at instruction start",
1904 exception[i].handler_pc.i);
1905 if (! (flags[exception[i].start_pc.i] & FLAG_INSN_START))
1906 verify_fail ("exception start not at instruction start",
1907 exception[i].start_pc.i);
1908 if (exception[i].end_pc.i != current_method->code_length
1909 && ! (flags[exception[i].end_pc.i] & FLAG_INSN_START))
1910 verify_fail ("exception end not at instruction start",
1911 exception[i].end_pc.i);
1913 flags[exception[i].handler_pc.i] |= FLAG_BRANCH_TARGET;
1917 void check_pool_index (int index)
1919 if (index < 0 || index >= current_class->constants.size)
1920 verify_fail ("constant pool index out of range", start_PC);
1923 type check_class_constant (int index)
1925 check_pool_index (index);
1926 _Jv_Constants *pool = ¤t_class->constants;
1927 if (pool->tags[index] == JV_CONSTANT_ResolvedClass)
1928 return type (pool->data[index].clazz, this);
1929 else if (pool->tags[index] == JV_CONSTANT_Class)
1930 return type (pool->data[index].utf8, this);
1931 verify_fail ("expected class constant", start_PC);
1934 type check_constant (int index)
1936 check_pool_index (index);
1937 _Jv_Constants *pool = ¤t_class->constants;
1938 if (pool->tags[index] == JV_CONSTANT_ResolvedString
1939 || pool->tags[index] == JV_CONSTANT_String)
1940 return type (&java::lang::String::class$, this);
1941 else if (pool->tags[index] == JV_CONSTANT_Integer)
1942 return type (int_type);
1943 else if (pool->tags[index] == JV_CONSTANT_Float)
1944 return type (float_type);
1945 verify_fail ("String, int, or float constant expected", start_PC);
1948 type check_wide_constant (int index)
1950 check_pool_index (index);
1951 _Jv_Constants *pool = ¤t_class->constants;
1952 if (pool->tags[index] == JV_CONSTANT_Long)
1953 return type (long_type);
1954 else if (pool->tags[index] == JV_CONSTANT_Double)
1955 return type (double_type);
1956 verify_fail ("long or double constant expected", start_PC);
1959 // Helper for both field and method. These are laid out the same in
1960 // the constant pool.
1961 type handle_field_or_method (int index, int expected,
1962 _Jv_Utf8Const **name,
1963 _Jv_Utf8Const **fmtype)
1965 check_pool_index (index);
1966 _Jv_Constants *pool = ¤t_class->constants;
1967 if (pool->tags[index] != expected)
1968 verify_fail ("didn't see expected constant", start_PC);
1969 // Once we know we have a Fieldref or Methodref we assume that it
1970 // is correctly laid out in the constant pool. I think the code
1971 // in defineclass.cc guarantees this.
1972 _Jv_ushort class_index, name_and_type_index;
1973 _Jv_loadIndexes (&pool->data[index],
1975 name_and_type_index);
1976 _Jv_ushort name_index, desc_index;
1977 _Jv_loadIndexes (&pool->data[name_and_type_index],
1978 name_index, desc_index);
1980 *name = pool->data[name_index].utf8;
1981 *fmtype = pool->data[desc_index].utf8;
1983 return check_class_constant (class_index);
1986 // Return field's type, compute class' type if requested.
1987 type check_field_constant (int index, type *class_type = NULL)
1989 _Jv_Utf8Const *name, *field_type;
1990 type ct = handle_field_or_method (index,
1991 JV_CONSTANT_Fieldref,
1992 &name, &field_type);
1995 if (field_type->data[0] == '[' || field_type->data[0] == 'L')
1996 return type (field_type, this);
1997 return get_type_val_for_signature (field_type->data[0]);
2000 type check_method_constant (int index, bool is_interface,
2001 _Jv_Utf8Const **method_name,
2002 _Jv_Utf8Const **method_signature)
2004 return handle_field_or_method (index,
2006 ? JV_CONSTANT_InterfaceMethodref
2007 : JV_CONSTANT_Methodref),
2008 method_name, method_signature);
2011 type get_one_type (char *&p)
2029 _Jv_Utf8Const *name = make_utf8_const (start, p - start);
2030 return type (name, this);
2033 // Casting to jchar here is ok since we are looking at an ASCII
2035 type_val rt = get_type_val_for_signature (jchar (v));
2037 if (arraycount == 0)
2039 // Callers of this function eventually push their arguments on
2040 // the stack. So, promote them here.
2041 return type (rt).promote ();
2044 jclass k = construct_primitive_array_type (rt);
2045 while (--arraycount > 0)
2046 k = _Jv_GetArrayClass (k, NULL);
2047 return type (k, this);
2050 void compute_argument_types (_Jv_Utf8Const *signature,
2053 char *p = signature->data;
2059 types[i++] = get_one_type (p);
2062 type compute_return_type (_Jv_Utf8Const *signature)
2064 char *p = signature->data;
2068 return get_one_type (p);
2071 void check_return_type (type onstack)
2073 type rt = compute_return_type (current_method->self->signature);
2074 if (! rt.compatible (onstack, this))
2075 verify_fail ("incompatible return type");
2078 // Initialize the stack for the new method. Returns true if this
2079 // method is an instance initializer.
2080 bool initialize_stack ()
2083 bool is_init = _Jv_equalUtf8Consts (current_method->self->name,
2085 bool is_clinit = _Jv_equalUtf8Consts (current_method->self->name,
2088 using namespace java::lang::reflect;
2089 if (! Modifier::isStatic (current_method->self->accflags))
2091 type kurr (current_class, this);
2094 kurr.set_uninitialized (type::SELF, this);
2098 verify_fail ("<clinit> method must be static");
2099 set_variable (0, kurr);
2100 current_state->set_this_type (kurr);
2106 verify_fail ("<init> method must be non-static");
2109 // We have to handle wide arguments specially here.
2110 int arg_count = _Jv_count_arguments (current_method->self->signature);
2111 type arg_types[arg_count];
2112 compute_argument_types (current_method->self->signature, arg_types);
2113 for (int i = 0; i < arg_count; ++i)
2115 set_variable (var, arg_types[i]);
2117 if (arg_types[i].iswide ())
2124 void verify_instructions_0 ()
2126 current_state = new state (current_method->max_stack,
2127 current_method->max_locals);
2132 // True if we are verifying an instance initializer.
2133 bool this_is_init = initialize_stack ();
2135 states = (linked<state> **) _Jv_Malloc (sizeof (linked<state> *)
2136 * current_method->code_length);
2137 for (int i = 0; i < current_method->code_length; ++i)
2140 next_verify_state = NULL;
2144 // If the PC was invalidated, get a new one from the work list.
2145 if (PC == state::NO_NEXT)
2147 state *new_state = pop_jump ();
2148 // If it is null, we're done.
2149 if (new_state == NULL)
2152 PC = new_state->get_pc ();
2153 debug_print ("== State pop from pending list\n");
2154 // Set up the current state.
2155 current_state->copy (new_state, current_method->max_stack,
2156 current_method->max_locals);
2160 // We only have to do this checking in the situation where
2161 // control flow falls through from the previous
2162 // instruction. Otherwise merging is done at the time we
2164 if (states[PC] != NULL)
2166 // We've already visited this instruction. So merge
2167 // the states together. It is simplest, but not most
2168 // efficient, to just always invalidate the PC here.
2169 merge_into (PC, current_state);
2175 // Control can't fall off the end of the bytecode. We need to
2176 // check this in both cases, not just the fall-through case,
2177 // because we don't check to see whether a `jsr' appears at
2178 // the end of the bytecode until we process a `ret'.
2179 if (PC >= current_method->code_length)
2180 verify_fail ("fell off end");
2182 // We only have to keep saved state at branch targets. If
2183 // we're at a branch target and the state here hasn't been set
2184 // yet, we set it now. You might notice that `ret' targets
2185 // won't necessarily have FLAG_BRANCH_TARGET set. This
2186 // doesn't matter, since those states will be filled in by
2188 if (states[PC] == NULL && (flags[PC] & FLAG_BRANCH_TARGET))
2189 add_new_state (PC, current_state);
2191 // Set this before handling exceptions so that debug output is
2195 // Update states for all active exception handlers. Ordinarily
2196 // there are not many exception handlers. So we simply run
2197 // through them all.
2198 for (int i = 0; i < current_method->exc_count; ++i)
2200 if (PC >= exception[i].start_pc.i && PC < exception[i].end_pc.i)
2202 type handler (&java::lang::Throwable::class$, this);
2203 if (exception[i].handler_type.i != 0)
2204 handler = check_class_constant (exception[i].handler_type.i);
2205 push_exception_jump (handler, exception[i].handler_pc.i);
2209 current_state->print (" ", PC, current_method->max_stack,
2210 current_method->max_locals);
2211 java_opcode opcode = (java_opcode) bytecode[PC++];
2217 case op_aconst_null:
2218 push_type (null_type);
2228 push_type (int_type);
2233 push_type (long_type);
2239 push_type (float_type);
2244 push_type (double_type);
2249 push_type (int_type);
2254 push_type (int_type);
2258 push_type (check_constant (get_byte ()));
2261 push_type (check_constant (get_ushort ()));
2264 push_type (check_wide_constant (get_ushort ()));
2268 push_type (get_variable (get_byte (), int_type));
2271 push_type (get_variable (get_byte (), long_type));
2274 push_type (get_variable (get_byte (), float_type));
2277 push_type (get_variable (get_byte (), double_type));
2280 push_type (get_variable (get_byte (), reference_type));
2287 push_type (get_variable (opcode - op_iload_0, int_type));
2293 push_type (get_variable (opcode - op_lload_0, long_type));
2299 push_type (get_variable (opcode - op_fload_0, float_type));
2305 push_type (get_variable (opcode - op_dload_0, double_type));
2311 push_type (get_variable (opcode - op_aload_0, 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 push_type (require_array_type (pop_init_ref (reference_type),
2339 pop_type (int_type);
2340 require_array_type (pop_init_ref (reference_type), byte_type);
2341 push_type (int_type);
2344 pop_type (int_type);
2345 require_array_type (pop_init_ref (reference_type), char_type);
2346 push_type (int_type);
2349 pop_type (int_type);
2350 require_array_type (pop_init_ref (reference_type), short_type);
2351 push_type (int_type);
2354 set_variable (get_byte (), pop_type (int_type));
2357 set_variable (get_byte (), pop_type (long_type));
2360 set_variable (get_byte (), pop_type (float_type));
2363 set_variable (get_byte (), pop_type (double_type));
2366 set_variable (get_byte (), pop_ref_or_return ());
2372 set_variable (opcode - op_istore_0, pop_type (int_type));
2378 set_variable (opcode - op_lstore_0, pop_type (long_type));
2384 set_variable (opcode - op_fstore_0, pop_type (float_type));
2390 set_variable (opcode - op_dstore_0, pop_type (double_type));
2396 set_variable (opcode - op_astore_0, pop_ref_or_return ());
2399 pop_type (int_type);
2400 pop_type (int_type);
2401 require_array_type (pop_init_ref (reference_type), int_type);
2404 pop_type (long_type);
2405 pop_type (int_type);
2406 require_array_type (pop_init_ref (reference_type), long_type);
2409 pop_type (float_type);
2410 pop_type (int_type);
2411 require_array_type (pop_init_ref (reference_type), float_type);
2414 pop_type (double_type);
2415 pop_type (int_type);
2416 require_array_type (pop_init_ref (reference_type), double_type);
2419 pop_type (reference_type);
2420 pop_type (int_type);
2421 require_array_type (pop_init_ref (reference_type), reference_type);
2424 pop_type (int_type);
2425 pop_type (int_type);
2426 require_array_type (pop_init_ref (reference_type), byte_type);
2429 pop_type (int_type);
2430 pop_type (int_type);
2431 require_array_type (pop_init_ref (reference_type), char_type);
2434 pop_type (int_type);
2435 pop_type (int_type);
2436 require_array_type (pop_init_ref (reference_type), short_type);
2443 type t = pop_raw ();
2467 type t2 = pop_raw ();
2482 type t = pop_raw ();
2497 type t1 = pop_raw ();
2514 type t1 = pop_raw ();
2517 type t2 = pop_raw ();
2535 type t3 = pop_raw ();
2573 pop_type (int_type);
2574 push_type (pop_type (int_type));
2584 pop_type (long_type);
2585 push_type (pop_type (long_type));
2590 pop_type (int_type);
2591 push_type (pop_type (long_type));
2598 pop_type (float_type);
2599 push_type (pop_type (float_type));
2606 pop_type (double_type);
2607 push_type (pop_type (double_type));
2613 push_type (pop_type (int_type));
2616 push_type (pop_type (long_type));
2619 push_type (pop_type (float_type));
2622 push_type (pop_type (double_type));
2625 get_variable (get_byte (), int_type);
2629 pop_type (int_type);
2630 push_type (long_type);
2633 pop_type (int_type);
2634 push_type (float_type);
2637 pop_type (int_type);
2638 push_type (double_type);
2641 pop_type (long_type);
2642 push_type (int_type);
2645 pop_type (long_type);
2646 push_type (float_type);
2649 pop_type (long_type);
2650 push_type (double_type);
2653 pop_type (float_type);
2654 push_type (int_type);
2657 pop_type (float_type);
2658 push_type (long_type);
2661 pop_type (float_type);
2662 push_type (double_type);
2665 pop_type (double_type);
2666 push_type (int_type);
2669 pop_type (double_type);
2670 push_type (long_type);
2673 pop_type (double_type);
2674 push_type (float_type);
2677 pop_type (long_type);
2678 pop_type (long_type);
2679 push_type (int_type);
2683 pop_type (float_type);
2684 pop_type (float_type);
2685 push_type (int_type);
2689 pop_type (double_type);
2690 pop_type (double_type);
2691 push_type (int_type);
2699 pop_type (int_type);
2700 push_jump (get_short ());
2708 pop_type (int_type);
2709 pop_type (int_type);
2710 push_jump (get_short ());
2714 pop_type (reference_type);
2715 pop_type (reference_type);
2716 push_jump (get_short ());
2719 push_jump (get_short ());
2723 handle_jsr_insn (get_short ());
2726 handle_ret_insn (get_byte ());
2728 case op_tableswitch:
2730 pop_type (int_type);
2732 push_jump (get_int ());
2733 jint low = get_int ();
2734 jint high = get_int ();
2735 // Already checked LOW -vs- HIGH.
2736 for (int i = low; i <= high; ++i)
2737 push_jump (get_int ());
2742 case op_lookupswitch:
2744 pop_type (int_type);
2746 push_jump (get_int ());
2747 jint npairs = get_int ();
2748 // Already checked NPAIRS >= 0.
2750 for (int i = 0; i < npairs; ++i)
2752 jint key = get_int ();
2753 if (i > 0 && key <= lastkey)
2754 verify_fail ("lookupswitch pairs unsorted", start_PC);
2756 push_jump (get_int ());
2762 check_return_type (pop_type (int_type));
2766 check_return_type (pop_type (long_type));
2770 check_return_type (pop_type (float_type));
2774 check_return_type (pop_type (double_type));
2778 check_return_type (pop_init_ref (reference_type));
2782 // We only need to check this when the return type is
2783 // void, because all instance initializers return void.
2785 current_state->check_this_initialized (this);
2786 check_return_type (void_type);
2790 push_type (check_field_constant (get_ushort ()));
2793 pop_type (check_field_constant (get_ushort ()));
2798 type field = check_field_constant (get_ushort (), &klass);
2806 type field = check_field_constant (get_ushort (), &klass);
2809 // We have an obscure special case here: we can use
2810 // `putfield' on a field declared in this class, even if
2811 // `this' has not yet been initialized.
2812 if (! current_state->this_type.isinitialized ()
2813 && current_state->this_type.pc == type::SELF)
2814 klass.set_uninitialized (type::SELF, this);
2819 case op_invokevirtual:
2820 case op_invokespecial:
2821 case op_invokestatic:
2822 case op_invokeinterface:
2824 _Jv_Utf8Const *method_name, *method_signature;
2826 = check_method_constant (get_ushort (),
2827 opcode == op_invokeinterface,
2830 // NARGS is only used when we're processing
2831 // invokeinterface. It is simplest for us to compute it
2832 // here and then verify it later.
2834 if (opcode == op_invokeinterface)
2836 nargs = get_byte ();
2837 if (get_byte () != 0)
2838 verify_fail ("invokeinterface dummy byte is wrong");
2841 bool is_init = false;
2842 if (_Jv_equalUtf8Consts (method_name, gcj::init_name))
2845 if (opcode != op_invokespecial)
2846 verify_fail ("can't invoke <init>");
2848 else if (method_name->data[0] == '<')
2849 verify_fail ("can't invoke method starting with `<'");
2851 // Pop arguments and check types.
2852 int arg_count = _Jv_count_arguments (method_signature);
2853 type arg_types[arg_count];
2854 compute_argument_types (method_signature, arg_types);
2855 for (int i = arg_count - 1; i >= 0; --i)
2857 // This is only used for verifying the byte for
2859 nargs -= arg_types[i].depth ();
2860 pop_init_ref (arg_types[i]);
2863 if (opcode == op_invokeinterface
2865 verify_fail ("wrong argument count for invokeinterface");
2867 if (opcode != op_invokestatic)
2869 type t = class_type;
2872 // In this case the PC doesn't matter.
2873 t.set_uninitialized (type::UNINIT, this);
2874 // FIXME: check to make sure that the <init>
2875 // call is to the right class.
2876 // It must either be super or an exact class
2879 type raw = pop_raw ();
2880 if (! t.compatible (raw, this))
2881 verify_fail ("incompatible type on stack");
2884 current_state->set_initialized (raw.get_pc (),
2885 current_method->max_locals);
2888 type rt = compute_return_type (method_signature);
2896 type t = check_class_constant (get_ushort ());
2897 if (t.isarray () || t.isinterface (this) || t.isabstract (this))
2898 verify_fail ("type is array, interface, or abstract");
2899 t.set_uninitialized (start_PC, this);
2906 int atype = get_byte ();
2907 // We intentionally have chosen constants to make this
2909 if (atype < boolean_type || atype > long_type)
2910 verify_fail ("type not primitive", start_PC);
2911 pop_type (int_type);
2912 type t (construct_primitive_array_type (type_val (atype)), this);
2917 pop_type (int_type);
2918 push_type (check_class_constant (get_ushort ()).to_array (this));
2920 case op_arraylength:
2922 type t = pop_init_ref (reference_type);
2923 if (! t.isarray () && ! t.isnull ())
2924 verify_fail ("array type expected");
2925 push_type (int_type);
2929 pop_type (type (&java::lang::Throwable::class$, this));
2933 pop_init_ref (reference_type);
2934 push_type (check_class_constant (get_ushort ()));
2937 pop_init_ref (reference_type);
2938 check_class_constant (get_ushort ());
2939 push_type (int_type);
2941 case op_monitorenter:
2942 pop_init_ref (reference_type);
2944 case op_monitorexit:
2945 pop_init_ref (reference_type);
2949 switch (get_byte ())
2952 push_type (get_variable (get_ushort (), int_type));
2955 push_type (get_variable (get_ushort (), long_type));
2958 push_type (get_variable (get_ushort (), float_type));
2961 push_type (get_variable (get_ushort (), double_type));
2964 push_type (get_variable (get_ushort (), reference_type));
2967 set_variable (get_ushort (), pop_type (int_type));
2970 set_variable (get_ushort (), pop_type (long_type));
2973 set_variable (get_ushort (), pop_type (float_type));
2976 set_variable (get_ushort (), pop_type (double_type));
2979 set_variable (get_ushort (), pop_init_ref (reference_type));
2982 handle_ret_insn (get_short ());
2985 get_variable (get_ushort (), int_type);
2989 verify_fail ("unrecognized wide instruction", start_PC);
2993 case op_multianewarray:
2995 type atype = check_class_constant (get_ushort ());
2996 int dim = get_byte ();
2998 verify_fail ("too few dimensions to multianewarray", start_PC);
2999 atype.verify_dimensions (dim, this);
3000 for (int i = 0; i < dim; ++i)
3001 pop_type (int_type);
3007 pop_type (reference_type);
3008 push_jump (get_short ());
3011 push_jump (get_int ());
3015 handle_jsr_insn (get_int ());
3018 // These are unused here, but we call them out explicitly
3019 // so that -Wswitch-enum doesn't complain.
3025 case op_putstatic_1:
3026 case op_putstatic_2:
3027 case op_putstatic_4:
3028 case op_putstatic_8:
3029 case op_putstatic_a:
3031 case op_getfield_2s:
3032 case op_getfield_2u:
3036 case op_getstatic_1:
3037 case op_getstatic_2s:
3038 case op_getstatic_2u:
3039 case op_getstatic_4:
3040 case op_getstatic_8:
3041 case op_getstatic_a:
3043 // Unrecognized opcode.
3044 verify_fail ("unrecognized instruction in verify_instructions_0",
3052 void verify_instructions ()
3055 verify_instructions_0 ();
3058 _Jv_BytecodeVerifier (_Jv_InterpMethod *m)
3060 // We just print the text as utf-8. This is just for debugging
3062 debug_print ("--------------------------------\n");
3063 debug_print ("-- Verifying method `%s'\n", m->self->name->data);
3066 bytecode = m->bytecode ();
3067 exception = m->exceptions ();
3068 current_class = m->defining_class;
3076 ~_Jv_BytecodeVerifier ()
3081 while (utf8_list != NULL)
3083 linked<_Jv_Utf8Const> *n = utf8_list->next;
3084 _Jv_Free (utf8_list->val);
3085 _Jv_Free (utf8_list);
3089 while (isect_list != NULL)
3091 ref_intersection *next = isect_list->alloc_next;
3098 for (int i = 0; i < current_method->code_length; ++i)
3100 linked<state> *iter = states[i];
3101 while (iter != NULL)
3103 linked<state> *next = iter->next;
3115 _Jv_VerifyMethod (_Jv_InterpMethod *meth)
3117 _Jv_BytecodeVerifier v (meth);
3118 v.verify_instructions ();
3121 #endif /* INTERPRETER */