1 // verify.cc - verify bytecode
3 /* Copyright (C) 2001, 2002, 2003 Free Software Foundation
5 This file is part of libgcj.
7 This software is copyrighted work licensed under the terms of the
8 Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
11 // Written by Tom Tromey <tromey@redhat.com>
13 // Define VERIFY_DEBUG to enable debugging output.
19 #include <java-insns.h>
20 #include <java-interp.h>
24 #include <java/lang/Class.h>
25 #include <java/lang/VerifyError.h>
26 #include <java/lang/Throwable.h>
27 #include <java/lang/reflect/Modifier.h>
28 #include <java/lang/StringBuffer.h>
32 #endif /* VERIFY_DEBUG */
35 static void debug_print (const char *fmt, ...)
36 __attribute__ ((format (printf, 1, 2)));
39 debug_print (const char *fmt, ...)
44 vfprintf (stderr, fmt, ap);
46 #endif /* VERIFY_DEBUG */
49 class _Jv_BytecodeVerifier
53 static const int FLAG_INSN_START = 1;
54 static const int FLAG_BRANCH_TARGET = 2;
59 struct subr_entry_info;
61 struct ref_intersection;
65 // The PC corresponding to the start of the current instruction.
68 // The current state of the stack, locals, etc.
71 // We store the state at branch targets, for merging. This holds
75 // We keep a linked list of all the PCs which we must reverify.
76 // The link is done using the PC values. This is the head of the
80 // We keep some flags for each instruction. The values are the
81 // FLAG_* constants defined above.
84 // We need to keep track of which instructions can call a given
85 // subroutine. FIXME: this is inefficient. We keep a linked list
86 // of all calling `jsr's at at each jsr target.
89 // We keep a linked list of entries which map each `ret' instruction
90 // to its unique subroutine entry point. We expect that there won't
91 // be many `ret' instructions, so a linked list is ok.
92 subr_entry_info *entry_points;
94 // The bytecode itself.
95 unsigned char *bytecode;
97 _Jv_InterpException *exception;
100 jclass current_class;
102 _Jv_InterpMethod *current_method;
104 // A linked list of utf8 objects we allocate. This is really ugly,
105 // but without this our utf8 objects would be collected.
106 linked_utf8 *utf8_list;
108 // A linked list of all ref_intersection objects we allocate.
109 ref_intersection *isect_list;
117 _Jv_Utf8Const *make_utf8_const (char *s, int len)
119 _Jv_Utf8Const *val = _Jv_makeUtf8Const (s, len);
120 _Jv_Utf8Const *r = (_Jv_Utf8Const *) _Jv_Malloc (sizeof (_Jv_Utf8Const)
123 r->length = val->length;
125 memcpy (r->data, val->data, val->length + 1);
127 linked_utf8 *lu = (linked_utf8 *) _Jv_Malloc (sizeof (linked_utf8));
129 lu->next = utf8_list;
135 __attribute__ ((__noreturn__)) void verify_fail (char *s, jint pc = -1)
137 using namespace java::lang;
138 StringBuffer *buf = new StringBuffer ();
140 buf->append (JvNewStringLatin1 ("verification failed"));
145 buf->append (JvNewStringLatin1 (" at PC "));
149 _Jv_InterpMethod *method = current_method;
150 buf->append (JvNewStringLatin1 (" in "));
151 buf->append (current_class->getName());
152 buf->append ((jchar) ':');
153 buf->append (JvNewStringUTF (method->get_method()->name->data));
154 buf->append ((jchar) '(');
155 buf->append (JvNewStringUTF (method->get_method()->signature->data));
156 buf->append ((jchar) ')');
158 buf->append (JvNewStringLatin1 (": "));
159 buf->append (JvNewStringLatin1 (s));
160 throw new java::lang::VerifyError (buf->toString ());
163 // This enum holds a list of tags for all the different types we
164 // need to handle. Reference types are treated specially by the
170 // The values for primitive types are chosen to correspond to values
171 // specified to newarray.
181 // Used when overwriting second word of a double or long in the
182 // local variables. Also used after merging local variable states
183 // to indicate an unusable value.
188 // There is an obscure special case which requires us to note when
189 // a local variable has not been used by a subroutine. See
190 // push_jump_merge for more information.
191 unused_by_subroutine_type,
193 // Everything after `reference_type' must be a reference type.
196 uninitialized_reference_type
199 // This represents a merged class type. Some verifiers (including
200 // earlier versions of this one) will compute the intersection of
201 // two class types when merging states. However, this loses
202 // critical information about interfaces implemented by the various
203 // classes. So instead we keep track of all the actual classes that
205 struct ref_intersection
207 // Whether or not this type has been resolved.
213 // For a resolved reference type, this is a pointer to the class.
215 // For other reference types, this it the name of the class.
219 // Link to the next reference in the intersection.
220 ref_intersection *ref_next;
222 // This is used to keep track of all the allocated
223 // ref_intersection objects, so we can free them.
224 // FIXME: we should allocate these in chunks.
225 ref_intersection *alloc_next;
227 ref_intersection (jclass klass, _Jv_BytecodeVerifier *verifier)
232 alloc_next = verifier->isect_list;
233 verifier->isect_list = this;
236 ref_intersection (_Jv_Utf8Const *name, _Jv_BytecodeVerifier *verifier)
241 alloc_next = verifier->isect_list;
242 verifier->isect_list = this;
245 ref_intersection (ref_intersection *dup, ref_intersection *tail,
246 _Jv_BytecodeVerifier *verifier)
249 is_resolved = dup->is_resolved;
251 alloc_next = verifier->isect_list;
252 verifier->isect_list = this;
255 bool equals (ref_intersection *other, _Jv_BytecodeVerifier *verifier)
257 if (! is_resolved && ! other->is_resolved
258 && _Jv_equalUtf8Consts (data.name, other->data.name))
262 if (! other->is_resolved)
263 other->resolve (verifier);
264 return data.klass == other->data.klass;
267 // Merge THIS type into OTHER, returning the result. This will
268 // return OTHER if all the classes in THIS already appear in
270 ref_intersection *merge (ref_intersection *other,
271 _Jv_BytecodeVerifier *verifier)
273 ref_intersection *tail = other;
274 for (ref_intersection *self = this; self != NULL; self = self->ref_next)
277 for (ref_intersection *iter = other; iter != NULL;
278 iter = iter->ref_next)
280 if (iter->equals (self, verifier))
288 tail = new ref_intersection (self, tail, verifier);
293 void resolve (_Jv_BytecodeVerifier *verifier)
298 using namespace java::lang;
299 java::lang::ClassLoader *loader
300 = verifier->current_class->getClassLoaderInternal();
301 // We might see either kind of name. Sigh.
302 if (data.name->data[0] == 'L'
303 && data.name->data[data.name->length - 1] == ';')
304 data.klass = _Jv_FindClassFromSignature (data.name->data, loader);
306 data.klass = Class::forName (_Jv_NewStringUtf8Const (data.name),
311 // See if an object of type OTHER can be assigned to an object of
312 // type *THIS. This might resolve classes in one chain or the
314 bool compatible (ref_intersection *other,
315 _Jv_BytecodeVerifier *verifier)
317 ref_intersection *self = this;
319 for (; self != NULL; self = self->ref_next)
321 ref_intersection *other_iter = other;
323 for (; other_iter != NULL; other_iter = other_iter->ref_next)
325 // Avoid resolving if possible.
326 if (! self->is_resolved
327 && ! other_iter->is_resolved
328 && _Jv_equalUtf8Consts (self->data.name,
329 other_iter->data.name))
332 if (! self->is_resolved)
333 self->resolve(verifier);
334 if (! other_iter->is_resolved)
335 other_iter->resolve(verifier);
337 if (! is_assignable_from_slow (self->data.klass,
338 other_iter->data.klass))
348 // assert (ref_next == NULL);
350 return data.klass->isArray ();
352 return data.name->data[0] == '[';
355 bool isinterface (_Jv_BytecodeVerifier *verifier)
357 // assert (ref_next == NULL);
360 return data.klass->isInterface ();
363 bool isabstract (_Jv_BytecodeVerifier *verifier)
365 // assert (ref_next == NULL);
368 using namespace java::lang::reflect;
369 return Modifier::isAbstract (data.klass->getModifiers ());
372 jclass getclass (_Jv_BytecodeVerifier *verifier)
379 int count_dimensions ()
384 jclass k = data.klass;
385 while (k->isArray ())
387 k = k->getComponentType ();
393 char *p = data.name->data;
400 void *operator new (size_t bytes)
402 return _Jv_Malloc (bytes);
405 void operator delete (void *mem)
411 // Return the type_val corresponding to a primitive signature
412 // character. For instance `I' returns `int.class'.
413 type_val get_type_val_for_signature (jchar sig)
446 verify_fail ("invalid signature");
451 // Return the type_val corresponding to a primitive class.
452 type_val get_type_val_for_signature (jclass k)
454 return get_type_val_for_signature ((jchar) k->method_count);
457 // This is like _Jv_IsAssignableFrom, but it works even if SOURCE or
458 // TARGET haven't been prepared.
459 static bool is_assignable_from_slow (jclass target, jclass source)
461 // First, strip arrays.
462 while (target->isArray ())
464 // If target is array, source must be as well.
465 if (! source->isArray ())
467 target = target->getComponentType ();
468 source = source->getComponentType ();
472 if (target == &java::lang::Object::class$)
477 if (source == target)
480 if (target->isPrimitive () || source->isPrimitive ())
483 if (target->isInterface ())
485 for (int i = 0; i < source->interface_count; ++i)
487 // We use a recursive call because we also need to
488 // check superinterfaces.
489 if (is_assignable_from_slow (target, source->interfaces[i]))
493 source = source->getSuperclass ();
495 while (source != NULL);
500 // This is used to keep track of which `jsr's correspond to a given
504 // PC of the instruction just after the jsr.
510 // This is used to keep track of which subroutine entry point
511 // corresponds to which `ret' instruction.
512 struct subr_entry_info
514 // PC of the subroutine entry point.
516 // PC of the `ret' instruction.
519 subr_entry_info *next;
522 // The `type' class is used to represent a single type in the
529 // For reference types, the representation of the type.
530 ref_intersection *klass;
532 // This is used when constructing a new object. It is the PC of the
533 // `new' instruction which created the object. We use the special
534 // value -2 to mean that this is uninitialized, and the special
535 // value -1 for the case where the current method is itself the
539 static const int UNINIT = -2;
540 static const int SELF = -1;
542 // Basic constructor.
545 key = unsuitable_type;
550 // Make a new instance given the type tag. We assume a generic
551 // `reference_type' means Object.
555 // For reference_type, if KLASS==NULL then that means we are
556 // looking for a generic object of any kind, including an
557 // uninitialized reference.
562 // Make a new instance given a class.
563 type (jclass k, _Jv_BytecodeVerifier *verifier)
565 key = reference_type;
566 klass = new ref_intersection (k, verifier);
570 // Make a new instance given the name of a class.
571 type (_Jv_Utf8Const *n, _Jv_BytecodeVerifier *verifier)
573 key = reference_type;
574 klass = new ref_intersection (n, verifier);
586 // These operators are required because libgcj can't link in
588 void *operator new[] (size_t bytes)
590 return _Jv_Malloc (bytes);
593 void operator delete[] (void *mem)
598 type& operator= (type_val k)
606 type& operator= (const type& t)
614 // Promote a numeric type.
617 if (key == boolean_type || key == char_type
618 || key == byte_type || key == short_type)
623 // Mark this type as the uninitialized result of `new'.
624 void set_uninitialized (int npc, _Jv_BytecodeVerifier *verifier)
626 if (key == reference_type)
627 key = uninitialized_reference_type;
629 verifier->verify_fail ("internal error in type::uninitialized");
633 // Mark this type as now initialized.
634 void set_initialized (int npc)
636 if (npc != UNINIT && pc == npc && key == uninitialized_reference_type)
638 key = reference_type;
644 // Return true if an object of type K can be assigned to a variable
645 // of type *THIS. Handle various special cases too. Might modify
646 // *THIS or K. Note however that this does not perform numeric
648 bool compatible (type &k, _Jv_BytecodeVerifier *verifier)
650 // Any type is compatible with the unsuitable type.
651 if (key == unsuitable_type)
654 if (key < reference_type || k.key < reference_type)
657 // The `null' type is convertible to any initialized reference
659 if (key == null_type)
660 return k.key != uninitialized_reference_type;
661 if (k.key == null_type)
662 return key != uninitialized_reference_type;
664 // A special case for a generic reference.
668 verifier->verify_fail ("programmer error in type::compatible");
670 // An initialized type and an uninitialized type are not
672 if (isinitialized () != k.isinitialized ())
675 // Two uninitialized objects are compatible if either:
676 // * The PCs are identical, or
677 // * One PC is UNINIT.
678 if (! isinitialized ())
680 if (pc != k.pc && pc != UNINIT && k.pc != UNINIT)
684 return klass->compatible(k.klass, verifier);
689 return key == void_type;
694 return key == long_type || key == double_type;
697 // Return number of stack or local variable slots taken by this
701 return iswide () ? 2 : 1;
704 bool isarray () const
706 // We treat null_type as not an array. This is ok based on the
707 // current uses of this method.
708 if (key == reference_type)
709 return klass->isarray ();
715 return key == null_type;
718 bool isinterface (_Jv_BytecodeVerifier *verifier)
720 if (key != reference_type)
722 return klass->isinterface (verifier);
725 bool isabstract (_Jv_BytecodeVerifier *verifier)
727 if (key != reference_type)
729 return klass->isabstract (verifier);
732 // Return the element type of an array.
733 type element_type (_Jv_BytecodeVerifier *verifier)
735 if (key != reference_type)
736 verifier->verify_fail ("programmer error in type::element_type()", -1);
738 jclass k = klass->getclass (verifier)->getComponentType ();
739 if (k->isPrimitive ())
740 return type (verifier->get_type_val_for_signature (k));
741 return type (k, verifier);
744 // Return the array type corresponding to an initialized
745 // reference. We could expand this to work for other kinds of
746 // types, but currently we don't need to.
747 type to_array (_Jv_BytecodeVerifier *verifier)
749 if (key != reference_type)
750 verifier->verify_fail ("internal error in type::to_array()");
752 jclass k = klass->getclass (verifier);
753 return type (_Jv_GetArrayClass (k, k->getClassLoaderInternal()),
757 bool isreference () const
759 return key >= reference_type;
767 bool isinitialized () const
769 return key == reference_type || key == null_type;
772 bool isresolved () const
774 return (key == reference_type
776 || key == uninitialized_reference_type);
779 void verify_dimensions (int ndims, _Jv_BytecodeVerifier *verifier)
781 // The way this is written, we don't need to check isarray().
782 if (key != reference_type)
783 verifier->verify_fail ("internal error in verify_dimensions: not a reference type");
785 if (klass->count_dimensions () < ndims)
786 verifier->verify_fail ("array type has fewer dimensions than required");
789 // Merge OLD_TYPE into this. On error throw exception.
790 bool merge (type& old_type, bool local_semantics,
791 _Jv_BytecodeVerifier *verifier)
793 bool changed = false;
794 bool refo = old_type.isreference ();
795 bool refn = isreference ();
798 if (old_type.key == null_type)
800 else if (key == null_type)
805 else if (isinitialized () != old_type.isinitialized ())
806 verifier->verify_fail ("merging initialized and uninitialized types");
809 if (! isinitialized ())
813 else if (old_type.pc == UNINIT)
815 else if (pc != old_type.pc)
816 verifier->verify_fail ("merging different uninitialized types");
819 ref_intersection *merged = old_type.klass->merge (klass,
828 else if (refo || refn || key != old_type.key)
832 // If we're merging into an "unused" slot, then we
833 // simply accept whatever we're merging from.
834 if (key == unused_by_subroutine_type)
839 else if (old_type.key == unused_by_subroutine_type)
843 // If we already have an `unsuitable' type, then we
844 // don't need to change again.
845 else if (key != unsuitable_type)
847 key = unsuitable_type;
852 verifier->verify_fail ("unmergeable type");
858 void print (void) const
863 case boolean_type: c = 'Z'; break;
864 case byte_type: c = 'B'; break;
865 case char_type: c = 'C'; break;
866 case short_type: c = 'S'; break;
867 case int_type: c = 'I'; break;
868 case long_type: c = 'J'; break;
869 case float_type: c = 'F'; break;
870 case double_type: c = 'D'; break;
871 case void_type: c = 'V'; break;
872 case unsuitable_type: c = '-'; break;
873 case return_address_type: c = 'r'; break;
874 case continuation_type: c = '+'; break;
875 case unused_by_subroutine_type: c = '_'; break;
876 case reference_type: c = 'L'; break;
877 case null_type: c = '@'; break;
878 case uninitialized_reference_type: c = 'U'; break;
880 debug_print ("%c", c);
882 #endif /* VERIFY_DEBUG */
885 // This class holds all the state information we need for a given
889 // The current top of the stack, in terms of slots.
891 // The current depth of the stack. This will be larger than
892 // STACKTOP when wide types are on the stack.
896 // The local variables.
898 // This is used in subroutines to keep track of which local
899 // variables have been accessed.
901 // If not 0, then we are in a subroutine. The value is the PC of
902 // the subroutine's entry point. We can use 0 as an exceptional
903 // value because PC=0 can never be a subroutine.
905 // This is used to keep a linked list of all the states which
906 // require re-verification. We use the PC to keep track.
908 // We keep track of the type of `this' specially. This is used to
909 // ensure that an instance initializer invokes another initializer
910 // on `this' before returning. We must keep track of this
911 // specially because otherwise we might be confused by code which
912 // assigns to locals[0] (overwriting `this') and then returns
913 // without really initializing.
915 // This is a list of all subroutines that have been seen at this
916 // point. Ordinarily this is NULL; it is only allocated and used
917 // in relatively weird situations involving non-ret exit from a
918 // subroutine. We have to keep track of this in this way to avoid
919 // endless recursion in these cases.
920 subr_info *seen_subrs;
922 // INVALID marks a state which is not on the linked list of states
923 // requiring reverification.
924 static const int INVALID = -1;
925 // NO_NEXT marks the state at the end of the reverification list.
926 static const int NO_NEXT = -2;
928 // This is used to mark the stack depth at the instruction just
929 // after a `jsr' when we haven't yet processed the corresponding
930 // `ret'. See handle_jsr_insn for more information.
931 static const int NO_STACK = -1;
938 local_changed = NULL;
942 state (int max_stack, int max_locals)
947 stack = new type[max_stack];
948 for (int i = 0; i < max_stack; ++i)
949 stack[i] = unsuitable_type;
950 locals = new type[max_locals];
951 local_changed = (bool *) _Jv_Malloc (sizeof (bool) * max_locals);
953 for (int i = 0; i < max_locals; ++i)
955 locals[i] = unsuitable_type;
956 local_changed[i] = false;
962 state (const state *orig, int max_stack, int max_locals,
963 bool ret_semantics = false)
965 stack = new type[max_stack];
966 locals = new type[max_locals];
967 local_changed = (bool *) _Jv_Malloc (sizeof (bool) * max_locals);
969 copy (orig, max_stack, max_locals, ret_semantics);
980 _Jv_Free (local_changed);
984 void *operator new[] (size_t bytes)
986 return _Jv_Malloc (bytes);
989 void operator delete[] (void *mem)
994 void *operator new (size_t bytes)
996 return _Jv_Malloc (bytes);
999 void operator delete (void *mem)
1006 subr_info *info = seen_subrs;
1007 while (info != NULL)
1009 subr_info *next = info->next;
1016 void copy (const state *copy, int max_stack, int max_locals,
1017 bool ret_semantics = false)
1019 stacktop = copy->stacktop;
1020 stackdepth = copy->stackdepth;
1021 subroutine = copy->subroutine;
1022 for (int i = 0; i < max_stack; ++i)
1023 stack[i] = copy->stack[i];
1024 for (int i = 0; i < max_locals; ++i)
1026 // See push_jump_merge to understand this case.
1028 locals[i] = type (copy->local_changed[i]
1030 : unused_by_subroutine_type);
1032 locals[i] = copy->locals[i];
1033 local_changed[i] = subroutine ? copy->local_changed[i] : false;
1037 if (copy->seen_subrs)
1039 for (subr_info *info = copy->seen_subrs;
1040 info != NULL; info = info->next)
1041 add_subr (info->pc);
1044 this_type = copy->this_type;
1045 // Don't modify `next'.
1048 // Modify this state to reflect entry to an exception handler.
1049 void set_exception (type t, int max_stack)
1054 for (int i = stacktop; i < max_stack; ++i)
1055 stack[i] = unsuitable_type;
1058 // Modify this state to reflect entry into a subroutine.
1059 void enter_subroutine (int npc, int max_locals)
1062 // Mark all items as unchanged. Each subroutine needs to keep
1063 // track of its `changed' state independently. In the case of
1064 // nested subroutines, this information will be merged back into
1065 // parent by the `ret'.
1066 for (int i = 0; i < max_locals; ++i)
1067 local_changed[i] = false;
1070 // Indicate that we've been in this this subroutine.
1071 void add_subr (int pc)
1073 subr_info *n = (subr_info *) _Jv_Malloc (sizeof (subr_info));
1075 n->next = seen_subrs;
1079 // Merge STATE_OLD into this state. Destructively modifies this
1080 // state. Returns true if the new state was in fact changed.
1081 // Will throw an exception if the states are not mergeable.
1082 bool merge (state *state_old, bool ret_semantics,
1083 int max_locals, _Jv_BytecodeVerifier *verifier)
1085 bool changed = false;
1087 // Special handling for `this'. If one or the other is
1088 // uninitialized, then the merge is uninitialized.
1089 if (this_type.isinitialized ())
1090 this_type = state_old->this_type;
1092 // Merge subroutine states. Here we just keep track of what
1093 // subroutine we think we're in. We only check for a merge
1094 // (which is invalid) when we see a `ret'.
1095 if (subroutine == state_old->subroutine)
1099 else if (subroutine == 0)
1101 subroutine = state_old->subroutine;
1106 // If the subroutines differ, and we haven't seen this
1107 // subroutine before, indicate that the state changed. This
1108 // is needed to detect when subroutines have merged.
1110 for (subr_info *info = seen_subrs; info != NULL; info = info->next)
1112 if (info->pc == state_old->subroutine)
1120 add_subr (state_old->subroutine);
1125 // Merge stacks. Special handling for NO_STACK case.
1126 if (state_old->stacktop == NO_STACK)
1128 // Nothing to do in this case; we don't care about modifying
1131 else if (stacktop == NO_STACK)
1133 stacktop = state_old->stacktop;
1134 stackdepth = state_old->stackdepth;
1135 for (int i = 0; i < stacktop; ++i)
1136 stack[i] = state_old->stack[i];
1139 else if (state_old->stacktop != stacktop)
1140 verifier->verify_fail ("stack sizes differ");
1143 for (int i = 0; i < state_old->stacktop; ++i)
1145 if (stack[i].merge (state_old->stack[i], false, verifier))
1150 // Merge local variables.
1151 for (int i = 0; i < max_locals; ++i)
1153 // If we're not processing a `ret', then we merge every
1154 // local variable. If we are processing a `ret', then we
1155 // only merge locals which changed in the subroutine. When
1156 // processing a `ret', STATE_OLD is the state at the point
1157 // of the `ret', and THIS is the state just after the `jsr'.
1158 if (! ret_semantics || state_old->local_changed[i])
1160 if (locals[i].merge (state_old->locals[i], true, verifier))
1162 // Note that we don't call `note_variable' here.
1163 // This change doesn't represent a real change to a
1164 // local, but rather a merge artifact. If we're in
1165 // a subroutine which is called with two
1166 // incompatible types in a slot that is unused by
1167 // the subroutine, then we don't want to mark that
1168 // variable as having been modified.
1173 // If we're in a subroutine, we must compute the union of
1174 // all the changed local variables.
1175 if (state_old->local_changed[i])
1182 // Throw an exception if there is an uninitialized object on the
1183 // stack or in a local variable. EXCEPTION_SEMANTICS controls
1184 // whether we're using backwards-branch or exception-handing
1186 void check_no_uninitialized_objects (int max_locals,
1187 _Jv_BytecodeVerifier *verifier,
1188 bool exception_semantics = false)
1190 if (! exception_semantics)
1192 for (int i = 0; i < stacktop; ++i)
1193 if (stack[i].isreference () && ! stack[i].isinitialized ())
1194 verifier->verify_fail ("uninitialized object on stack");
1197 for (int i = 0; i < max_locals; ++i)
1198 if (locals[i].isreference () && ! locals[i].isinitialized ())
1199 verifier->verify_fail ("uninitialized object in local variable");
1201 check_this_initialized (verifier);
1204 // Ensure that `this' has been initialized.
1205 void check_this_initialized (_Jv_BytecodeVerifier *verifier)
1207 if (this_type.isreference () && ! this_type.isinitialized ())
1208 verifier->verify_fail ("`this' is uninitialized");
1211 // Set type of `this'.
1212 void set_this_type (const type &k)
1217 // Note that a local variable was modified.
1218 void note_variable (int index)
1221 local_changed[index] = true;
1224 // Mark each `new'd object we know of that was allocated at PC as
1226 void set_initialized (int pc, int max_locals)
1228 for (int i = 0; i < stacktop; ++i)
1229 stack[i].set_initialized (pc);
1230 for (int i = 0; i < max_locals; ++i)
1231 locals[i].set_initialized (pc);
1232 this_type.set_initialized (pc);
1235 // Return true if this state is the unmerged result of a `ret'.
1236 bool is_unmerged_ret_state (int max_locals) const
1238 if (stacktop == NO_STACK)
1240 for (int i = 0; i < max_locals; ++i)
1242 if (locals[i].key == unused_by_subroutine_type)
1249 void print (const char *leader, int pc,
1250 int max_stack, int max_locals) const
1252 debug_print ("%s [%4d]: [stack] ", leader, pc);
1254 for (i = 0; i < stacktop; ++i)
1256 for (; i < max_stack; ++i)
1258 debug_print (" [local] ");
1259 for (i = 0; i < max_locals; ++i)
1262 debug_print (local_changed[i] ? "+" : " ");
1264 if (subroutine == 0)
1265 debug_print (" | None");
1267 debug_print (" | %4d", subroutine);
1268 debug_print (" | %p\n", this);
1271 inline void print (const char *, int, int, int) const
1274 #endif /* VERIFY_DEBUG */
1279 if (current_state->stacktop <= 0)
1280 verify_fail ("stack empty");
1281 type r = current_state->stack[--current_state->stacktop];
1282 current_state->stackdepth -= r.depth ();
1283 if (current_state->stackdepth < 0)
1284 verify_fail ("stack empty", start_PC);
1290 type r = pop_raw ();
1292 verify_fail ("narrow pop of wide type");
1296 type pop_type (type match)
1299 type t = pop_raw ();
1300 if (! match.compatible (t, this))
1301 verify_fail ("incompatible type on stack");
1305 // Pop a reference which is guaranteed to be initialized. MATCH
1306 // doesn't have to be a reference type; in this case this acts like
1308 type pop_init_ref (type match)
1310 type t = pop_raw ();
1311 if (t.isreference () && ! t.isinitialized ())
1312 verify_fail ("initialized reference required");
1313 else if (! match.compatible (t, this))
1314 verify_fail ("incompatible type on stack");
1318 // Pop a reference type or a return address.
1319 type pop_ref_or_return ()
1321 type t = pop_raw ();
1322 if (! t.isreference () && t.key != return_address_type)
1323 verify_fail ("expected reference or return address on stack");
1327 void push_type (type t)
1329 // If T is a numeric type like short, promote it to int.
1332 int depth = t.depth ();
1333 if (current_state->stackdepth + depth > current_method->max_stack)
1334 verify_fail ("stack overflow");
1335 current_state->stack[current_state->stacktop++] = t;
1336 current_state->stackdepth += depth;
1339 void set_variable (int index, type t)
1341 // If T is a numeric type like short, promote it to int.
1344 int depth = t.depth ();
1345 if (index > current_method->max_locals - depth)
1346 verify_fail ("invalid local variable");
1347 current_state->locals[index] = t;
1348 current_state->note_variable (index);
1352 current_state->locals[index + 1] = continuation_type;
1353 current_state->note_variable (index + 1);
1355 if (index > 0 && current_state->locals[index - 1].iswide ())
1357 current_state->locals[index - 1] = unsuitable_type;
1358 // There's no need to call note_variable here.
1362 type get_variable (int index, type t)
1364 int depth = t.depth ();
1365 if (index > current_method->max_locals - depth)
1366 verify_fail ("invalid local variable");
1367 if (! t.compatible (current_state->locals[index], this))
1368 verify_fail ("incompatible type in local variable");
1371 type t (continuation_type);
1372 if (! current_state->locals[index + 1].compatible (t, this))
1373 verify_fail ("invalid local variable");
1375 return current_state->locals[index];
1378 // Make sure ARRAY is an array type and that its elements are
1379 // compatible with type ELEMENT. Returns the actual element type.
1380 type require_array_type (type array, type element)
1382 // An odd case. Here we just pretend that everything went ok. If
1383 // the requested element type is some kind of reference, return
1384 // the null type instead.
1385 if (array.isnull ())
1386 return element.isreference () ? type (null_type) : element;
1388 if (! array.isarray ())
1389 verify_fail ("array required");
1391 type t = array.element_type (this);
1392 if (! element.compatible (t, this))
1394 // Special case for byte arrays, which must also be boolean
1397 if (element.key == byte_type)
1399 type e2 (boolean_type);
1400 ok = e2.compatible (t, this);
1403 verify_fail ("incompatible array element type");
1406 // Return T and not ELEMENT, because T might be specialized.
1412 if (PC >= current_method->code_length)
1413 verify_fail ("premature end of bytecode");
1414 return (jint) bytecode[PC++] & 0xff;
1419 jint b1 = get_byte ();
1420 jint b2 = get_byte ();
1421 return (jint) ((b1 << 8) | b2) & 0xffff;
1426 jint b1 = get_byte ();
1427 jint b2 = get_byte ();
1428 jshort s = (b1 << 8) | b2;
1434 jint b1 = get_byte ();
1435 jint b2 = get_byte ();
1436 jint b3 = get_byte ();
1437 jint b4 = get_byte ();
1438 return (b1 << 24) | (b2 << 16) | (b3 << 8) | b4;
1441 int compute_jump (int offset)
1443 int npc = start_PC + offset;
1444 if (npc < 0 || npc >= current_method->code_length)
1445 verify_fail ("branch out of range", start_PC);
1449 // Merge the indicated state into the state at the branch target and
1450 // schedule a new PC if there is a change. If RET_SEMANTICS is
1451 // true, then we are merging from a `ret' instruction into the
1452 // instruction after a `jsr'. This is a special case with its own
1453 // modified semantics.
1454 void push_jump_merge (int npc, state *nstate, bool ret_semantics = false)
1456 bool changed = true;
1457 if (states[npc] == NULL)
1459 // There's a weird situation here. If are examining the
1460 // branch that results from a `ret', and there is not yet a
1461 // state available at the branch target (the instruction just
1462 // after the `jsr'), then we have to construct a special kind
1463 // of state at that point for future merging. This special
1464 // state has the type `unused_by_subroutine_type' in each slot
1465 // which was not modified by the subroutine.
1466 states[npc] = new state (nstate, current_method->max_stack,
1467 current_method->max_locals, ret_semantics);
1468 debug_print ("== New state in push_jump_merge (ret_semantics = %s)\n",
1469 ret_semantics ? "true" : "false");
1470 states[npc]->print ("New", npc, current_method->max_stack,
1471 current_method->max_locals);
1475 debug_print ("== Merge states in push_jump_merge\n");
1476 nstate->print ("Frm", start_PC, current_method->max_stack,
1477 current_method->max_locals);
1478 states[npc]->print (" To", npc, current_method->max_stack,
1479 current_method->max_locals);
1480 changed = states[npc]->merge (nstate, ret_semantics,
1481 current_method->max_locals, this);
1482 states[npc]->print ("New", npc, current_method->max_stack,
1483 current_method->max_locals);
1486 if (changed && states[npc]->next == state::INVALID)
1488 // The merge changed the state, and the new PC isn't yet on our
1489 // list of PCs to re-verify.
1490 states[npc]->next = next_verify_pc;
1491 next_verify_pc = npc;
1495 void push_jump (int offset)
1497 int npc = compute_jump (offset);
1499 current_state->check_no_uninitialized_objects (current_method->max_locals, this);
1500 push_jump_merge (npc, current_state);
1503 void push_exception_jump (type t, int pc)
1505 current_state->check_no_uninitialized_objects (current_method->max_locals,
1507 state s (current_state, current_method->max_stack,
1508 current_method->max_locals);
1509 if (current_method->max_stack < 1)
1510 verify_fail ("stack overflow at exception handler");
1511 s.set_exception (t, current_method->max_stack);
1512 push_jump_merge (pc, &s);
1517 int *prev_loc = &next_verify_pc;
1518 int npc = next_verify_pc;
1520 while (npc != state::NO_NEXT)
1522 // If the next available PC is an unmerged `ret' state, then
1523 // we aren't yet ready to handle it. That's because we would
1524 // need all kind of special cases to do so. So instead we
1525 // defer this jump until after we've processed it via a
1526 // fall-through. This has to happen because the instruction
1527 // before this one must be a `jsr'.
1528 if (! states[npc]->is_unmerged_ret_state (current_method->max_locals))
1530 *prev_loc = states[npc]->next;
1531 states[npc]->next = state::INVALID;
1535 prev_loc = &states[npc]->next;
1536 npc = states[npc]->next;
1539 // Note that we might have gotten here even when there are
1540 // remaining states to process. That can happen if we find a
1541 // `jsr' without a `ret'.
1542 return state::NO_NEXT;
1545 void invalidate_pc ()
1547 PC = state::NO_NEXT;
1550 void note_branch_target (int pc, bool is_jsr_target = false)
1552 // Don't check `pc <= PC', because we've advanced PC after
1553 // fetching the target and we haven't yet checked the next
1555 if (pc < PC && ! (flags[pc] & FLAG_INSN_START))
1556 verify_fail ("branch not to instruction start", start_PC);
1557 flags[pc] |= FLAG_BRANCH_TARGET;
1560 // Record the jsr which called this instruction.
1561 subr_info *info = (subr_info *) _Jv_Malloc (sizeof (subr_info));
1563 info->next = jsr_ptrs[pc];
1564 jsr_ptrs[pc] = info;
1568 void skip_padding ()
1570 while ((PC % 4) > 0)
1571 if (get_byte () != 0)
1572 verify_fail ("found nonzero padding byte");
1575 // Return the subroutine to which the instruction at PC belongs.
1576 int get_subroutine (int pc)
1578 if (states[pc] == NULL)
1580 return states[pc]->subroutine;
1583 // Do the work for a `ret' instruction. INDEX is the index into the
1585 void handle_ret_insn (int index)
1587 get_variable (index, return_address_type);
1589 int csub = current_state->subroutine;
1591 verify_fail ("no subroutine");
1593 // Check to see if we've merged subroutines.
1594 subr_entry_info *entry;
1595 for (entry = entry_points; entry != NULL; entry = entry->next)
1597 if (entry->ret_pc == start_PC)
1602 entry = (subr_entry_info *) _Jv_Malloc (sizeof (subr_entry_info));
1604 entry->ret_pc = start_PC;
1605 entry->next = entry_points;
1606 entry_points = entry;
1608 else if (entry->pc != csub)
1609 verify_fail ("subroutines merged");
1611 for (subr_info *subr = jsr_ptrs[csub]; subr != NULL; subr = subr->next)
1613 // We might be returning to a `jsr' that is at the end of the
1614 // bytecode. This is ok if we never return from the called
1615 // subroutine, but if we see this here it is an error.
1616 if (subr->pc >= current_method->code_length)
1617 verify_fail ("fell off end");
1619 // Temporarily modify the current state so it looks like we're
1620 // in the enclosing context.
1621 current_state->subroutine = get_subroutine (subr->pc);
1623 current_state->check_no_uninitialized_objects (current_method->max_locals, this);
1624 push_jump_merge (subr->pc, current_state, true);
1627 current_state->subroutine = csub;
1631 // We're in the subroutine SUB, calling a subroutine at DEST. Make
1632 // sure this subroutine isn't already on the stack.
1633 void check_nonrecursive_call (int sub, int dest)
1638 verify_fail ("recursive subroutine call");
1639 for (subr_info *info = jsr_ptrs[sub]; info != NULL; info = info->next)
1640 check_nonrecursive_call (get_subroutine (info->pc), dest);
1643 void handle_jsr_insn (int offset)
1645 int npc = compute_jump (offset);
1648 current_state->check_no_uninitialized_objects (current_method->max_locals, this);
1649 check_nonrecursive_call (current_state->subroutine, npc);
1651 // Modify our state as appropriate for entry into a subroutine.
1652 push_type (return_address_type);
1653 push_jump_merge (npc, current_state);
1655 pop_type (return_address_type);
1657 // On entry to the subroutine, the subroutine number must be set
1658 // and the locals must be marked as cleared. We do this after
1659 // merging state so that we don't erroneously "notice" a variable
1660 // change merely on entry.
1661 states[npc]->enter_subroutine (npc, current_method->max_locals);
1663 // Indicate that we don't know the stack depth of the instruction
1664 // following the `jsr'. The idea here is that we need to merge
1665 // the local variable state across the jsr, but the subroutine
1666 // might change the stack depth, so we can't make any assumptions
1667 // about it. So we have yet another special case. We know that
1668 // at this point PC points to the instruction after the jsr. Note
1669 // that it is ok to have a `jsr' at the end of the bytecode,
1670 // provided that the called subroutine never returns. So, we have
1671 // a special case here and another one when we handle the ret.
1672 if (PC < current_method->code_length)
1674 current_state->stacktop = state::NO_STACK;
1675 push_jump_merge (PC, current_state);
1680 jclass construct_primitive_array_type (type_val prim)
1686 k = JvPrimClass (boolean);
1689 k = JvPrimClass (char);
1692 k = JvPrimClass (float);
1695 k = JvPrimClass (double);
1698 k = JvPrimClass (byte);
1701 k = JvPrimClass (short);
1704 k = JvPrimClass (int);
1707 k = JvPrimClass (long);
1710 // These aren't used here but we call them out to avoid
1713 case unsuitable_type:
1714 case return_address_type:
1715 case continuation_type:
1716 case unused_by_subroutine_type:
1717 case reference_type:
1719 case uninitialized_reference_type:
1721 verify_fail ("unknown type in construct_primitive_array_type");
1723 k = _Jv_GetArrayClass (k, NULL);
1727 // This pass computes the location of branch targets and also
1728 // instruction starts.
1729 void branch_prepass ()
1731 flags = (char *) _Jv_Malloc (current_method->code_length);
1732 jsr_ptrs = (subr_info **) _Jv_Malloc (sizeof (subr_info *)
1733 * current_method->code_length);
1735 for (int i = 0; i < current_method->code_length; ++i)
1741 bool last_was_jsr = false;
1744 while (PC < current_method->code_length)
1746 // Set `start_PC' early so that error checking can have the
1749 flags[PC] |= FLAG_INSN_START;
1751 // If the previous instruction was a jsr, then the next
1752 // instruction is a branch target -- the branch being the
1753 // corresponding `ret'.
1755 note_branch_target (PC);
1756 last_was_jsr = false;
1758 java_opcode opcode = (java_opcode) bytecode[PC++];
1762 case op_aconst_null:
1898 case op_monitorenter:
1899 case op_monitorexit:
1907 case op_arraylength:
1939 case op_invokespecial:
1940 case op_invokestatic:
1941 case op_invokevirtual:
1945 case op_multianewarray:
1951 last_was_jsr = true;
1970 note_branch_target (compute_jump (get_short ()), last_was_jsr);
1973 case op_tableswitch:
1976 note_branch_target (compute_jump (get_int ()));
1977 jint low = get_int ();
1978 jint hi = get_int ();
1980 verify_fail ("invalid tableswitch", start_PC);
1981 for (int i = low; i <= hi; ++i)
1982 note_branch_target (compute_jump (get_int ()));
1986 case op_lookupswitch:
1989 note_branch_target (compute_jump (get_int ()));
1990 int npairs = get_int ();
1992 verify_fail ("too few pairs in lookupswitch", start_PC);
1993 while (npairs-- > 0)
1996 note_branch_target (compute_jump (get_int ()));
2001 case op_invokeinterface:
2009 opcode = (java_opcode) get_byte ();
2011 if (opcode == op_iinc)
2017 last_was_jsr = true;
2020 note_branch_target (compute_jump (get_int ()), last_was_jsr);
2023 // These are unused here, but we call them out explicitly
2024 // so that -Wswitch-enum doesn't complain.
2030 case op_putstatic_1:
2031 case op_putstatic_2:
2032 case op_putstatic_4:
2033 case op_putstatic_8:
2034 case op_putstatic_a:
2036 case op_getfield_2s:
2037 case op_getfield_2u:
2041 case op_getstatic_1:
2042 case op_getstatic_2s:
2043 case op_getstatic_2u:
2044 case op_getstatic_4:
2045 case op_getstatic_8:
2046 case op_getstatic_a:
2048 verify_fail ("unrecognized instruction in branch_prepass",
2052 // See if any previous branch tried to branch to the middle of
2053 // this instruction.
2054 for (int pc = start_PC + 1; pc < PC; ++pc)
2056 if ((flags[pc] & FLAG_BRANCH_TARGET))
2057 verify_fail ("branch to middle of instruction", pc);
2061 // Verify exception handlers.
2062 for (int i = 0; i < current_method->exc_count; ++i)
2064 if (! (flags[exception[i].handler_pc.i] & FLAG_INSN_START))
2065 verify_fail ("exception handler not at instruction start",
2066 exception[i].handler_pc.i);
2067 if (! (flags[exception[i].start_pc.i] & FLAG_INSN_START))
2068 verify_fail ("exception start not at instruction start",
2069 exception[i].start_pc.i);
2070 if (exception[i].end_pc.i != current_method->code_length
2071 && ! (flags[exception[i].end_pc.i] & FLAG_INSN_START))
2072 verify_fail ("exception end not at instruction start",
2073 exception[i].end_pc.i);
2075 flags[exception[i].handler_pc.i] |= FLAG_BRANCH_TARGET;
2079 void check_pool_index (int index)
2081 if (index < 0 || index >= current_class->constants.size)
2082 verify_fail ("constant pool index out of range", start_PC);
2085 type check_class_constant (int index)
2087 check_pool_index (index);
2088 _Jv_Constants *pool = ¤t_class->constants;
2089 if (pool->tags[index] == JV_CONSTANT_ResolvedClass)
2090 return type (pool->data[index].clazz, this);
2091 else if (pool->tags[index] == JV_CONSTANT_Class)
2092 return type (pool->data[index].utf8, this);
2093 verify_fail ("expected class constant", start_PC);
2096 type check_constant (int index)
2098 check_pool_index (index);
2099 _Jv_Constants *pool = ¤t_class->constants;
2100 if (pool->tags[index] == JV_CONSTANT_ResolvedString
2101 || pool->tags[index] == JV_CONSTANT_String)
2102 return type (&java::lang::String::class$, this);
2103 else if (pool->tags[index] == JV_CONSTANT_Integer)
2104 return type (int_type);
2105 else if (pool->tags[index] == JV_CONSTANT_Float)
2106 return type (float_type);
2107 verify_fail ("String, int, or float constant expected", start_PC);
2110 type check_wide_constant (int index)
2112 check_pool_index (index);
2113 _Jv_Constants *pool = ¤t_class->constants;
2114 if (pool->tags[index] == JV_CONSTANT_Long)
2115 return type (long_type);
2116 else if (pool->tags[index] == JV_CONSTANT_Double)
2117 return type (double_type);
2118 verify_fail ("long or double constant expected", start_PC);
2121 // Helper for both field and method. These are laid out the same in
2122 // the constant pool.
2123 type handle_field_or_method (int index, int expected,
2124 _Jv_Utf8Const **name,
2125 _Jv_Utf8Const **fmtype)
2127 check_pool_index (index);
2128 _Jv_Constants *pool = ¤t_class->constants;
2129 if (pool->tags[index] != expected)
2130 verify_fail ("didn't see expected constant", start_PC);
2131 // Once we know we have a Fieldref or Methodref we assume that it
2132 // is correctly laid out in the constant pool. I think the code
2133 // in defineclass.cc guarantees this.
2134 _Jv_ushort class_index, name_and_type_index;
2135 _Jv_loadIndexes (&pool->data[index],
2137 name_and_type_index);
2138 _Jv_ushort name_index, desc_index;
2139 _Jv_loadIndexes (&pool->data[name_and_type_index],
2140 name_index, desc_index);
2142 *name = pool->data[name_index].utf8;
2143 *fmtype = pool->data[desc_index].utf8;
2145 return check_class_constant (class_index);
2148 // Return field's type, compute class' type if requested.
2149 type check_field_constant (int index, type *class_type = NULL)
2151 _Jv_Utf8Const *name, *field_type;
2152 type ct = handle_field_or_method (index,
2153 JV_CONSTANT_Fieldref,
2154 &name, &field_type);
2157 if (field_type->data[0] == '[' || field_type->data[0] == 'L')
2158 return type (field_type, this);
2159 return get_type_val_for_signature (field_type->data[0]);
2162 type check_method_constant (int index, bool is_interface,
2163 _Jv_Utf8Const **method_name,
2164 _Jv_Utf8Const **method_signature)
2166 return handle_field_or_method (index,
2168 ? JV_CONSTANT_InterfaceMethodref
2169 : JV_CONSTANT_Methodref),
2170 method_name, method_signature);
2173 type get_one_type (char *&p)
2191 _Jv_Utf8Const *name = make_utf8_const (start, p - start);
2192 return type (name, this);
2195 // Casting to jchar here is ok since we are looking at an ASCII
2197 type_val rt = get_type_val_for_signature (jchar (v));
2199 if (arraycount == 0)
2201 // Callers of this function eventually push their arguments on
2202 // the stack. So, promote them here.
2203 return type (rt).promote ();
2206 jclass k = construct_primitive_array_type (rt);
2207 while (--arraycount > 0)
2208 k = _Jv_GetArrayClass (k, NULL);
2209 return type (k, this);
2212 void compute_argument_types (_Jv_Utf8Const *signature,
2215 char *p = signature->data;
2221 types[i++] = get_one_type (p);
2224 type compute_return_type (_Jv_Utf8Const *signature)
2226 char *p = signature->data;
2230 return get_one_type (p);
2233 void check_return_type (type onstack)
2235 type rt = compute_return_type (current_method->self->signature);
2236 if (! rt.compatible (onstack, this))
2237 verify_fail ("incompatible return type");
2240 // Initialize the stack for the new method. Returns true if this
2241 // method is an instance initializer.
2242 bool initialize_stack ()
2245 bool is_init = _Jv_equalUtf8Consts (current_method->self->name,
2247 bool is_clinit = _Jv_equalUtf8Consts (current_method->self->name,
2250 using namespace java::lang::reflect;
2251 if (! Modifier::isStatic (current_method->self->accflags))
2253 type kurr (current_class, this);
2256 kurr.set_uninitialized (type::SELF, this);
2260 verify_fail ("<clinit> method must be static");
2261 set_variable (0, kurr);
2262 current_state->set_this_type (kurr);
2268 verify_fail ("<init> method must be non-static");
2271 // We have to handle wide arguments specially here.
2272 int arg_count = _Jv_count_arguments (current_method->self->signature);
2273 type arg_types[arg_count];
2274 compute_argument_types (current_method->self->signature, arg_types);
2275 for (int i = 0; i < arg_count; ++i)
2277 set_variable (var, arg_types[i]);
2279 if (arg_types[i].iswide ())
2286 void verify_instructions_0 ()
2288 current_state = new state (current_method->max_stack,
2289 current_method->max_locals);
2294 // True if we are verifying an instance initializer.
2295 bool this_is_init = initialize_stack ();
2297 states = (state **) _Jv_Malloc (sizeof (state *)
2298 * current_method->code_length);
2299 for (int i = 0; i < current_method->code_length; ++i)
2302 next_verify_pc = state::NO_NEXT;
2306 // If the PC was invalidated, get a new one from the work list.
2307 if (PC == state::NO_NEXT)
2310 if (PC == state::INVALID)
2311 verify_fail ("can't happen: saw state::INVALID");
2312 if (PC == state::NO_NEXT)
2314 debug_print ("== State pop from pending list\n");
2315 // Set up the current state.
2316 current_state->copy (states[PC], current_method->max_stack,
2317 current_method->max_locals);
2321 // Control can't fall off the end of the bytecode. We
2322 // only need to check this in the fall-through case,
2323 // because branch bounds are checked when they are
2325 if (PC >= current_method->code_length)
2326 verify_fail ("fell off end");
2328 // We only have to do this checking in the situation where
2329 // control flow falls through from the previous
2330 // instruction. Otherwise merging is done at the time we
2332 if (states[PC] != NULL)
2334 // We've already visited this instruction. So merge
2335 // the states together. If this yields no change then
2336 // we don't have to re-verify. However, if the new
2337 // state is an the result of an unmerged `ret', we
2338 // must continue through it.
2339 debug_print ("== Fall through merge\n");
2340 states[PC]->print ("Old", PC, current_method->max_stack,
2341 current_method->max_locals);
2342 current_state->print ("Cur", PC, current_method->max_stack,
2343 current_method->max_locals);
2344 if (! current_state->merge (states[PC], false,
2345 current_method->max_locals, this)
2346 && ! states[PC]->is_unmerged_ret_state (current_method->max_locals))
2348 debug_print ("== Fall through optimization\n");
2352 // Save a copy of it for later.
2353 states[PC]->copy (current_state, current_method->max_stack,
2354 current_method->max_locals);
2355 current_state->print ("New", PC, current_method->max_stack,
2356 current_method->max_locals);
2360 // We only have to keep saved state at branch targets. If
2361 // we're at a branch target and the state here hasn't been set
2362 // yet, we set it now.
2363 if (states[PC] == NULL && (flags[PC] & FLAG_BRANCH_TARGET))
2365 states[PC] = new state (current_state, current_method->max_stack,
2366 current_method->max_locals);
2369 // Set this before handling exceptions so that debug output is
2373 // Update states for all active exception handlers. Ordinarily
2374 // there are not many exception handlers. So we simply run
2375 // through them all.
2376 for (int i = 0; i < current_method->exc_count; ++i)
2378 if (PC >= exception[i].start_pc.i && PC < exception[i].end_pc.i)
2380 type handler (&java::lang::Throwable::class$, this);
2381 if (exception[i].handler_type.i != 0)
2382 handler = check_class_constant (exception[i].handler_type.i);
2383 push_exception_jump (handler, exception[i].handler_pc.i);
2387 current_state->print (" ", PC, current_method->max_stack,
2388 current_method->max_locals);
2389 java_opcode opcode = (java_opcode) bytecode[PC++];
2395 case op_aconst_null:
2396 push_type (null_type);
2406 push_type (int_type);
2411 push_type (long_type);
2417 push_type (float_type);
2422 push_type (double_type);
2427 push_type (int_type);
2432 push_type (int_type);
2436 push_type (check_constant (get_byte ()));
2439 push_type (check_constant (get_ushort ()));
2442 push_type (check_wide_constant (get_ushort ()));
2446 push_type (get_variable (get_byte (), int_type));
2449 push_type (get_variable (get_byte (), long_type));
2452 push_type (get_variable (get_byte (), float_type));
2455 push_type (get_variable (get_byte (), double_type));
2458 push_type (get_variable (get_byte (), reference_type));
2465 push_type (get_variable (opcode - op_iload_0, int_type));
2471 push_type (get_variable (opcode - op_lload_0, long_type));
2477 push_type (get_variable (opcode - op_fload_0, float_type));
2483 push_type (get_variable (opcode - op_dload_0, double_type));
2489 push_type (get_variable (opcode - op_aload_0, reference_type));
2492 pop_type (int_type);
2493 push_type (require_array_type (pop_init_ref (reference_type),
2497 pop_type (int_type);
2498 push_type (require_array_type (pop_init_ref (reference_type),
2502 pop_type (int_type);
2503 push_type (require_array_type (pop_init_ref (reference_type),
2507 pop_type (int_type);
2508 push_type (require_array_type (pop_init_ref (reference_type),
2512 pop_type (int_type);
2513 push_type (require_array_type (pop_init_ref (reference_type),
2517 pop_type (int_type);
2518 require_array_type (pop_init_ref (reference_type), byte_type);
2519 push_type (int_type);
2522 pop_type (int_type);
2523 require_array_type (pop_init_ref (reference_type), char_type);
2524 push_type (int_type);
2527 pop_type (int_type);
2528 require_array_type (pop_init_ref (reference_type), short_type);
2529 push_type (int_type);
2532 set_variable (get_byte (), pop_type (int_type));
2535 set_variable (get_byte (), pop_type (long_type));
2538 set_variable (get_byte (), pop_type (float_type));
2541 set_variable (get_byte (), pop_type (double_type));
2544 set_variable (get_byte (), pop_ref_or_return ());
2550 set_variable (opcode - op_istore_0, pop_type (int_type));
2556 set_variable (opcode - op_lstore_0, pop_type (long_type));
2562 set_variable (opcode - op_fstore_0, pop_type (float_type));
2568 set_variable (opcode - op_dstore_0, pop_type (double_type));
2574 set_variable (opcode - op_astore_0, pop_ref_or_return ());
2577 pop_type (int_type);
2578 pop_type (int_type);
2579 require_array_type (pop_init_ref (reference_type), int_type);
2582 pop_type (long_type);
2583 pop_type (int_type);
2584 require_array_type (pop_init_ref (reference_type), long_type);
2587 pop_type (float_type);
2588 pop_type (int_type);
2589 require_array_type (pop_init_ref (reference_type), float_type);
2592 pop_type (double_type);
2593 pop_type (int_type);
2594 require_array_type (pop_init_ref (reference_type), double_type);
2597 pop_type (reference_type);
2598 pop_type (int_type);
2599 require_array_type (pop_init_ref (reference_type), reference_type);
2602 pop_type (int_type);
2603 pop_type (int_type);
2604 require_array_type (pop_init_ref (reference_type), byte_type);
2607 pop_type (int_type);
2608 pop_type (int_type);
2609 require_array_type (pop_init_ref (reference_type), char_type);
2612 pop_type (int_type);
2613 pop_type (int_type);
2614 require_array_type (pop_init_ref (reference_type), short_type);
2621 type t = pop_raw ();
2645 type t2 = pop_raw ();
2660 type t = pop_raw ();
2675 type t1 = pop_raw ();
2692 type t1 = pop_raw ();
2695 type t2 = pop_raw ();
2713 type t3 = pop_raw ();
2751 pop_type (int_type);
2752 push_type (pop_type (int_type));
2762 pop_type (long_type);
2763 push_type (pop_type (long_type));
2768 pop_type (int_type);
2769 push_type (pop_type (long_type));
2776 pop_type (float_type);
2777 push_type (pop_type (float_type));
2784 pop_type (double_type);
2785 push_type (pop_type (double_type));
2791 push_type (pop_type (int_type));
2794 push_type (pop_type (long_type));
2797 push_type (pop_type (float_type));
2800 push_type (pop_type (double_type));
2803 get_variable (get_byte (), int_type);
2807 pop_type (int_type);
2808 push_type (long_type);
2811 pop_type (int_type);
2812 push_type (float_type);
2815 pop_type (int_type);
2816 push_type (double_type);
2819 pop_type (long_type);
2820 push_type (int_type);
2823 pop_type (long_type);
2824 push_type (float_type);
2827 pop_type (long_type);
2828 push_type (double_type);
2831 pop_type (float_type);
2832 push_type (int_type);
2835 pop_type (float_type);
2836 push_type (long_type);
2839 pop_type (float_type);
2840 push_type (double_type);
2843 pop_type (double_type);
2844 push_type (int_type);
2847 pop_type (double_type);
2848 push_type (long_type);
2851 pop_type (double_type);
2852 push_type (float_type);
2855 pop_type (long_type);
2856 pop_type (long_type);
2857 push_type (int_type);
2861 pop_type (float_type);
2862 pop_type (float_type);
2863 push_type (int_type);
2867 pop_type (double_type);
2868 pop_type (double_type);
2869 push_type (int_type);
2877 pop_type (int_type);
2878 push_jump (get_short ());
2886 pop_type (int_type);
2887 pop_type (int_type);
2888 push_jump (get_short ());
2892 pop_type (reference_type);
2893 pop_type (reference_type);
2894 push_jump (get_short ());
2897 push_jump (get_short ());
2901 handle_jsr_insn (get_short ());
2904 handle_ret_insn (get_byte ());
2906 case op_tableswitch:
2908 pop_type (int_type);
2910 push_jump (get_int ());
2911 jint low = get_int ();
2912 jint high = get_int ();
2913 // Already checked LOW -vs- HIGH.
2914 for (int i = low; i <= high; ++i)
2915 push_jump (get_int ());
2920 case op_lookupswitch:
2922 pop_type (int_type);
2924 push_jump (get_int ());
2925 jint npairs = get_int ();
2926 // Already checked NPAIRS >= 0.
2928 for (int i = 0; i < npairs; ++i)
2930 jint key = get_int ();
2931 if (i > 0 && key <= lastkey)
2932 verify_fail ("lookupswitch pairs unsorted", start_PC);
2934 push_jump (get_int ());
2940 check_return_type (pop_type (int_type));
2944 check_return_type (pop_type (long_type));
2948 check_return_type (pop_type (float_type));
2952 check_return_type (pop_type (double_type));
2956 check_return_type (pop_init_ref (reference_type));
2960 // We only need to check this when the return type is
2961 // void, because all instance initializers return void.
2963 current_state->check_this_initialized (this);
2964 check_return_type (void_type);
2968 push_type (check_field_constant (get_ushort ()));
2971 pop_type (check_field_constant (get_ushort ()));
2976 type field = check_field_constant (get_ushort (), &klass);
2984 type field = check_field_constant (get_ushort (), &klass);
2987 // We have an obscure special case here: we can use
2988 // `putfield' on a field declared in this class, even if
2989 // `this' has not yet been initialized.
2990 if (! current_state->this_type.isinitialized ()
2991 && current_state->this_type.pc == type::SELF)
2992 klass.set_uninitialized (type::SELF, this);
2997 case op_invokevirtual:
2998 case op_invokespecial:
2999 case op_invokestatic:
3000 case op_invokeinterface:
3002 _Jv_Utf8Const *method_name, *method_signature;
3004 = check_method_constant (get_ushort (),
3005 opcode == op_invokeinterface,
3008 // NARGS is only used when we're processing
3009 // invokeinterface. It is simplest for us to compute it
3010 // here and then verify it later.
3012 if (opcode == op_invokeinterface)
3014 nargs = get_byte ();
3015 if (get_byte () != 0)
3016 verify_fail ("invokeinterface dummy byte is wrong");
3019 bool is_init = false;
3020 if (_Jv_equalUtf8Consts (method_name, gcj::init_name))
3023 if (opcode != op_invokespecial)
3024 verify_fail ("can't invoke <init>");
3026 else if (method_name->data[0] == '<')
3027 verify_fail ("can't invoke method starting with `<'");
3029 // Pop arguments and check types.
3030 int arg_count = _Jv_count_arguments (method_signature);
3031 type arg_types[arg_count];
3032 compute_argument_types (method_signature, arg_types);
3033 for (int i = arg_count - 1; i >= 0; --i)
3035 // This is only used for verifying the byte for
3037 nargs -= arg_types[i].depth ();
3038 pop_init_ref (arg_types[i]);
3041 if (opcode == op_invokeinterface
3043 verify_fail ("wrong argument count for invokeinterface");
3045 if (opcode != op_invokestatic)
3047 type t = class_type;
3050 // In this case the PC doesn't matter.
3051 t.set_uninitialized (type::UNINIT, this);
3052 // FIXME: check to make sure that the <init>
3053 // call is to the right class.
3054 // It must either be super or an exact class
3057 type raw = pop_raw ();
3058 if (! t.compatible (raw, this))
3059 verify_fail ("incompatible type on stack");
3062 current_state->set_initialized (raw.get_pc (),
3063 current_method->max_locals);
3066 type rt = compute_return_type (method_signature);
3074 type t = check_class_constant (get_ushort ());
3075 if (t.isarray () || t.isinterface (this) || t.isabstract (this))
3076 verify_fail ("type is array, interface, or abstract");
3077 t.set_uninitialized (start_PC, this);
3084 int atype = get_byte ();
3085 // We intentionally have chosen constants to make this
3087 if (atype < boolean_type || atype > long_type)
3088 verify_fail ("type not primitive", start_PC);
3089 pop_type (int_type);
3090 type t (construct_primitive_array_type (type_val (atype)), this);
3095 pop_type (int_type);
3096 push_type (check_class_constant (get_ushort ()).to_array (this));
3098 case op_arraylength:
3100 type t = pop_init_ref (reference_type);
3101 if (! t.isarray () && ! t.isnull ())
3102 verify_fail ("array type expected");
3103 push_type (int_type);
3107 pop_type (type (&java::lang::Throwable::class$, this));
3111 pop_init_ref (reference_type);
3112 push_type (check_class_constant (get_ushort ()));
3115 pop_init_ref (reference_type);
3116 check_class_constant (get_ushort ());
3117 push_type (int_type);
3119 case op_monitorenter:
3120 pop_init_ref (reference_type);
3122 case op_monitorexit:
3123 pop_init_ref (reference_type);
3127 switch (get_byte ())
3130 push_type (get_variable (get_ushort (), int_type));
3133 push_type (get_variable (get_ushort (), long_type));
3136 push_type (get_variable (get_ushort (), float_type));
3139 push_type (get_variable (get_ushort (), double_type));
3142 push_type (get_variable (get_ushort (), reference_type));
3145 set_variable (get_ushort (), pop_type (int_type));
3148 set_variable (get_ushort (), pop_type (long_type));
3151 set_variable (get_ushort (), pop_type (float_type));
3154 set_variable (get_ushort (), pop_type (double_type));
3157 set_variable (get_ushort (), pop_init_ref (reference_type));
3160 handle_ret_insn (get_short ());
3163 get_variable (get_ushort (), int_type);
3167 verify_fail ("unrecognized wide instruction", start_PC);
3171 case op_multianewarray:
3173 type atype = check_class_constant (get_ushort ());
3174 int dim = get_byte ();
3176 verify_fail ("too few dimensions to multianewarray", start_PC);
3177 atype.verify_dimensions (dim, this);
3178 for (int i = 0; i < dim; ++i)
3179 pop_type (int_type);
3185 pop_type (reference_type);
3186 push_jump (get_short ());
3189 push_jump (get_int ());
3193 handle_jsr_insn (get_int ());
3196 // These are unused here, but we call them out explicitly
3197 // so that -Wswitch-enum doesn't complain.
3203 case op_putstatic_1:
3204 case op_putstatic_2:
3205 case op_putstatic_4:
3206 case op_putstatic_8:
3207 case op_putstatic_a:
3209 case op_getfield_2s:
3210 case op_getfield_2u:
3214 case op_getstatic_1:
3215 case op_getstatic_2s:
3216 case op_getstatic_2u:
3217 case op_getstatic_4:
3218 case op_getstatic_8:
3219 case op_getstatic_a:
3221 // Unrecognized opcode.
3222 verify_fail ("unrecognized instruction in verify_instructions_0",
3230 void verify_instructions ()
3233 verify_instructions_0 ();
3236 _Jv_BytecodeVerifier (_Jv_InterpMethod *m)
3238 // We just print the text as utf-8. This is just for debugging
3240 debug_print ("--------------------------------\n");
3241 debug_print ("-- Verifying method `%s'\n", m->self->name->data);
3244 bytecode = m->bytecode ();
3245 exception = m->exceptions ();
3246 current_class = m->defining_class;
3253 entry_points = NULL;
3256 ~_Jv_BytecodeVerifier ()
3265 for (int i = 0; i < current_method->code_length; ++i)
3267 if (jsr_ptrs[i] != NULL)
3269 subr_info *info = jsr_ptrs[i];
3270 while (info != NULL)
3272 subr_info *next = info->next;
3278 _Jv_Free (jsr_ptrs);
3281 while (utf8_list != NULL)
3283 linked_utf8 *n = utf8_list->next;
3284 _Jv_Free (utf8_list->val);
3285 _Jv_Free (utf8_list);
3289 while (entry_points != NULL)
3291 subr_entry_info *next = entry_points->next;
3292 _Jv_Free (entry_points);
3293 entry_points = next;
3296 while (isect_list != NULL)
3298 ref_intersection *next = isect_list->alloc_next;
3306 _Jv_VerifyMethod (_Jv_InterpMethod *meth)
3308 _Jv_BytecodeVerifier v (meth);
3309 v.verify_instructions ();
3311 #endif /* INTERPRETER */