1 // defineclass.cc - defining a class from .class format.
3 /* Copyright (C) 2001, 2002 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;
64 // The PC corresponding to the start of the current instruction.
67 // The current state of the stack, locals, etc.
70 // We store the state at branch targets, for merging. This holds
74 // We keep a linked list of all the PCs which we must reverify.
75 // The link is done using the PC values. This is the head of the
79 // We keep some flags for each instruction. The values are the
80 // FLAG_* constants defined above.
83 // We need to keep track of which instructions can call a given
84 // subroutine. FIXME: this is inefficient. We keep a linked list
85 // of all calling `jsr's at at each jsr target.
88 // We keep a linked list of entries which map each `ret' instruction
89 // to its unique subroutine entry point. We expect that there won't
90 // be many `ret' instructions, so a linked list is ok.
91 subr_entry_info *entry_points;
93 // The bytecode itself.
94 unsigned char *bytecode;
96 _Jv_InterpException *exception;
101 _Jv_InterpMethod *current_method;
103 // A linked list of utf8 objects we allocate. This is really ugly,
104 // but without this our utf8 objects would be collected.
105 linked_utf8 *utf8_list;
113 _Jv_Utf8Const *make_utf8_const (char *s, int len)
115 _Jv_Utf8Const *val = _Jv_makeUtf8Const (s, len);
116 _Jv_Utf8Const *r = (_Jv_Utf8Const *) _Jv_Malloc (sizeof (_Jv_Utf8Const)
119 r->length = val->length;
121 memcpy (r->data, val->data, val->length + 1);
123 linked_utf8 *lu = (linked_utf8 *) _Jv_Malloc (sizeof (linked_utf8));
125 lu->next = utf8_list;
131 // This enum holds a list of tags for all the different types we
132 // need to handle. Reference types are treated specially by the
138 // The values for primitive types are chosen to correspond to values
139 // specified to newarray.
149 // Used when overwriting second word of a double or long in the
150 // local variables. Also used after merging local variable states
151 // to indicate an unusable value.
156 // There is an obscure special case which requires us to note when
157 // a local variable has not been used by a subroutine. See
158 // push_jump_merge for more information.
159 unused_by_subroutine_type,
161 // Everything after `reference_type' must be a reference type.
164 unresolved_reference_type,
165 uninitialized_reference_type,
166 uninitialized_unresolved_reference_type
169 // Return the type_val corresponding to a primitive signature
170 // character. For instance `I' returns `int.class'.
171 type_val get_type_val_for_signature (jchar sig)
204 verify_fail ("invalid signature");
209 // Return the type_val corresponding to a primitive class.
210 type_val get_type_val_for_signature (jclass k)
212 return get_type_val_for_signature ((jchar) k->method_count);
215 // This is like _Jv_IsAssignableFrom, but it works even if SOURCE or
216 // TARGET haven't been prepared.
217 static bool is_assignable_from_slow (jclass target, jclass source)
219 // This will terminate when SOURCE==Object.
222 if (source == target)
225 if (target->isPrimitive () || source->isPrimitive ())
228 if (target->isArray ())
230 if (! source->isArray ())
232 target = target->getComponentType ();
233 source = source->getComponentType ();
235 else if (target->isInterface ())
237 for (int i = 0; i < source->interface_count; ++i)
239 // We use a recursive call because we also need to
240 // check superinterfaces.
241 if (is_assignable_from_slow (target, source->interfaces[i]))
244 source = source->getSuperclass ();
248 // We must do this check before we check to see if SOURCE is
249 // an interface. This way we know that any interface is
250 // assignable to an Object.
251 else if (target == &java::lang::Object::class$)
253 else if (source->isInterface ())
255 for (int i = 0; i < target->interface_count; ++i)
257 // We use a recursive call because we also need to
258 // check superinterfaces.
259 if (is_assignable_from_slow (target->interfaces[i], source))
262 target = target->getSuperclass ();
266 else if (source == &java::lang::Object::class$)
269 source = source->getSuperclass ();
273 // This is used to keep track of which `jsr's correspond to a given
277 // PC of the instruction just after the jsr.
283 // This is used to keep track of which subroutine entry point
284 // corresponds to which `ret' instruction.
285 struct subr_entry_info
287 // PC of the subroutine entry point.
289 // PC of the `ret' instruction.
292 subr_entry_info *next;
295 // The `type' class is used to represent a single type in the
301 // Some associated data.
304 // For a resolved reference type, this is a pointer to the class.
306 // For other reference types, this it the name of the class.
309 // This is used when constructing a new object. It is the PC of the
310 // `new' instruction which created the object. We use the special
311 // value -2 to mean that this is uninitialized, and the special
312 // value -1 for the case where the current method is itself the
316 static const int UNINIT = -2;
317 static const int SELF = -1;
319 // Basic constructor.
322 key = unsuitable_type;
327 // Make a new instance given the type tag. We assume a generic
328 // `reference_type' means Object.
333 if (key == reference_type)
334 data.klass = &java::lang::Object::class$;
338 // Make a new instance given a class.
341 key = reference_type;
346 // Make a new instance given the name of a class.
347 type (_Jv_Utf8Const *n)
349 key = unresolved_reference_type;
362 // These operators are required because libgcj can't link in
364 void *operator new[] (size_t bytes)
366 return _Jv_Malloc (bytes);
369 void operator delete[] (void *mem)
374 type& operator= (type_val k)
382 type& operator= (const type& t)
390 // Promote a numeric type.
393 if (key == boolean_type || key == char_type
394 || key == byte_type || key == short_type)
399 // If *THIS is an unresolved reference type, resolve it.
400 void resolve (_Jv_BytecodeVerifier *verifier)
402 if (key != unresolved_reference_type
403 && key != uninitialized_unresolved_reference_type)
406 using namespace java::lang;
407 java::lang::ClassLoader *loader
408 = verifier->current_class->getClassLoaderInternal();
409 // We might see either kind of name. Sigh.
410 if (data.name->data[0] == 'L'
411 && data.name->data[data.name->length - 1] == ';')
412 data.klass = _Jv_FindClassFromSignature (data.name->data, loader);
414 data.klass = Class::forName (_Jv_NewStringUtf8Const (data.name),
416 key = (key == unresolved_reference_type
418 : uninitialized_reference_type);
421 // Mark this type as the uninitialized result of `new'.
422 void set_uninitialized (int npc, _Jv_BytecodeVerifier *verifier)
424 if (key == reference_type)
425 key = uninitialized_reference_type;
426 else if (key == unresolved_reference_type)
427 key = uninitialized_unresolved_reference_type;
429 verifier->verify_fail ("internal error in type::uninitialized");
433 // Mark this type as now initialized.
434 void set_initialized (int npc)
436 if (npc != UNINIT && pc == npc
437 && (key == uninitialized_reference_type
438 || key == uninitialized_unresolved_reference_type))
440 key = (key == uninitialized_reference_type
442 : unresolved_reference_type);
448 // Return true if an object of type K can be assigned to a variable
449 // of type *THIS. Handle various special cases too. Might modify
450 // *THIS or K. Note however that this does not perform numeric
452 bool compatible (type &k, _Jv_BytecodeVerifier *verifier)
454 // Any type is compatible with the unsuitable type.
455 if (key == unsuitable_type)
458 if (key < reference_type || k.key < reference_type)
461 // The `null' type is convertible to any initialized reference
463 if (key == null_type || k.key == null_type)
466 // Any reference type is convertible to Object. This is a special
467 // case so we don't need to unnecessarily resolve a class.
468 if (key == reference_type
469 && data.klass == &java::lang::Object::class$)
472 // An initialized type and an uninitialized type are not
474 if (isinitialized () != k.isinitialized ())
477 // Two uninitialized objects are compatible if either:
478 // * The PCs are identical, or
479 // * One PC is UNINIT.
480 if (! isinitialized ())
482 if (pc != k.pc && pc != UNINIT && k.pc != UNINIT)
486 // Two unresolved types are equal if their names are the same.
489 && _Jv_equalUtf8Consts (data.name, k.data.name))
492 // We must resolve both types and check assignability.
494 k.resolve (verifier);
495 return is_assignable_from_slow (data.klass, k.data.klass);
500 return key == void_type;
505 return key == long_type || key == double_type;
508 // Return number of stack or local variable slots taken by this
512 return iswide () ? 2 : 1;
515 bool isarray () const
517 // We treat null_type as not an array. This is ok based on the
518 // current uses of this method.
519 if (key == reference_type)
520 return data.klass->isArray ();
521 else if (key == unresolved_reference_type)
522 return data.name->data[0] == '[';
528 return key == null_type;
531 bool isinterface (_Jv_BytecodeVerifier *verifier)
534 if (key != reference_type)
536 return data.klass->isInterface ();
539 bool isabstract (_Jv_BytecodeVerifier *verifier)
542 if (key != reference_type)
544 using namespace java::lang::reflect;
545 return Modifier::isAbstract (data.klass->getModifiers ());
548 // Return the element type of an array.
549 type element_type (_Jv_BytecodeVerifier *verifier)
551 // FIXME: maybe should do string manipulation here.
553 if (key != reference_type)
554 verifier->verify_fail ("programmer error in type::element_type()", -1);
556 jclass k = data.klass->getComponentType ();
557 if (k->isPrimitive ())
558 return type (verifier->get_type_val_for_signature (k));
562 // Return the array type corresponding to an initialized
563 // reference. We could expand this to work for other kinds of
564 // types, but currently we don't need to.
565 type to_array (_Jv_BytecodeVerifier *verifier)
567 // Resolving isn't ideal, because it might force us to load
568 // another class, but it's easy. FIXME?
569 if (key == unresolved_reference_type)
572 if (key == reference_type)
573 return type (_Jv_GetArrayClass (data.klass,
574 data.klass->getClassLoaderInternal()));
576 verifier->verify_fail ("internal error in type::to_array()");
579 bool isreference () const
581 return key >= reference_type;
589 bool isinitialized () const
591 return (key == reference_type
593 || key == unresolved_reference_type);
596 bool isresolved () const
598 return (key == reference_type
600 || key == uninitialized_reference_type);
603 void verify_dimensions (int ndims, _Jv_BytecodeVerifier *verifier)
605 // The way this is written, we don't need to check isarray().
606 if (key == reference_type)
608 jclass k = data.klass;
609 while (k->isArray () && ndims > 0)
611 k = k->getComponentType ();
617 // We know KEY == unresolved_reference_type.
618 char *p = data.name->data;
619 while (*p++ == '[' && ndims-- > 0)
624 verifier->verify_fail ("array type has fewer dimensions than required");
627 // Merge OLD_TYPE into this. On error throw exception.
628 bool merge (type& old_type, bool local_semantics,
629 _Jv_BytecodeVerifier *verifier)
631 bool changed = false;
632 bool refo = old_type.isreference ();
633 bool refn = isreference ();
636 if (old_type.key == null_type)
638 else if (key == null_type)
643 else if (isinitialized () != old_type.isinitialized ())
644 verifier->verify_fail ("merging initialized and uninitialized types");
647 if (! isinitialized ())
651 else if (old_type.pc == UNINIT)
653 else if (pc != old_type.pc)
654 verifier->verify_fail ("merging different uninitialized types");
658 && ! old_type.isresolved ()
659 && _Jv_equalUtf8Consts (data.name, old_type.data.name))
661 // Types are identical.
666 old_type.resolve (verifier);
668 jclass k = data.klass;
669 jclass oldk = old_type.data.klass;
672 while (k->isArray () && oldk->isArray ())
675 k = k->getComponentType ();
676 oldk = oldk->getComponentType ();
679 // Ordinarily this terminates when we hit Object...
682 if (is_assignable_from_slow (k, oldk))
684 k = k->getSuperclass ();
687 // ... but K could have been an interface, in which
688 // case we'll end up here. We just convert this
691 k = &java::lang::Object::class$;
695 while (arraycount > 0)
697 java::lang::ClassLoader *loader
698 = verifier->current_class->getClassLoaderInternal();
699 k = _Jv_GetArrayClass (k, loader);
707 else if (refo || refn || key != old_type.key)
711 // If we're merging into an "unused" slot, then we
712 // simply accept whatever we're merging from.
713 if (key == unused_by_subroutine_type)
718 else if (old_type.key == unused_by_subroutine_type)
722 // If we already have an `unsuitable' type, then we
723 // don't need to change again.
724 else if (key != unsuitable_type)
726 key = unsuitable_type;
731 verifier->verify_fail ("unmergeable type");
737 void print (void) const
742 case boolean_type: c = 'Z'; break;
743 case byte_type: c = 'B'; break;
744 case char_type: c = 'C'; break;
745 case short_type: c = 'S'; break;
746 case int_type: c = 'I'; break;
747 case long_type: c = 'J'; break;
748 case float_type: c = 'F'; break;
749 case double_type: c = 'D'; break;
750 case void_type: c = 'V'; break;
751 case unsuitable_type: c = '-'; break;
752 case return_address_type: c = 'r'; break;
753 case continuation_type: c = '+'; break;
754 case unused_by_subroutine_type: c = '_'; break;
755 case reference_type: c = 'L'; break;
756 case null_type: c = '@'; break;
757 case unresolved_reference_type: c = 'l'; break;
758 case uninitialized_reference_type: c = 'U'; break;
759 case uninitialized_unresolved_reference_type: c = 'u'; break;
761 debug_print ("%c", c);
763 #endif /* VERIFY_DEBUG */
766 // This class holds all the state information we need for a given
770 // The current top of the stack, in terms of slots.
772 // The current depth of the stack. This will be larger than
773 // STACKTOP when wide types are on the stack.
777 // The local variables.
779 // This is used in subroutines to keep track of which local
780 // variables have been accessed.
782 // If not 0, then we are in a subroutine. The value is the PC of
783 // the subroutine's entry point. We can use 0 as an exceptional
784 // value because PC=0 can never be a subroutine.
786 // This is used to keep a linked list of all the states which
787 // require re-verification. We use the PC to keep track.
789 // We keep track of the type of `this' specially. This is used to
790 // ensure that an instance initializer invokes another initializer
791 // on `this' before returning. We must keep track of this
792 // specially because otherwise we might be confused by code which
793 // assigns to locals[0] (overwriting `this') and then returns
794 // without really initializing.
797 // INVALID marks a state which is not on the linked list of states
798 // requiring reverification.
799 static const int INVALID = -1;
800 // NO_NEXT marks the state at the end of the reverification list.
801 static const int NO_NEXT = -2;
803 // This is used to mark the stack depth at the instruction just
804 // after a `jsr' when we haven't yet processed the corresponding
805 // `ret'. See handle_jsr_insn for more information.
806 static const int NO_STACK = -1;
813 local_changed = NULL;
816 state (int max_stack, int max_locals)
821 stack = new type[max_stack];
822 for (int i = 0; i < max_stack; ++i)
823 stack[i] = unsuitable_type;
824 locals = new type[max_locals];
825 local_changed = (bool *) _Jv_Malloc (sizeof (bool) * max_locals);
826 for (int i = 0; i < max_locals; ++i)
828 locals[i] = unsuitable_type;
829 local_changed[i] = false;
835 state (const state *orig, int max_stack, int max_locals,
836 bool ret_semantics = false)
838 stack = new type[max_stack];
839 locals = new type[max_locals];
840 local_changed = (bool *) _Jv_Malloc (sizeof (bool) * max_locals);
841 copy (orig, max_stack, max_locals, ret_semantics);
852 _Jv_Free (local_changed);
855 void *operator new[] (size_t bytes)
857 return _Jv_Malloc (bytes);
860 void operator delete[] (void *mem)
865 void *operator new (size_t bytes)
867 return _Jv_Malloc (bytes);
870 void operator delete (void *mem)
875 void copy (const state *copy, int max_stack, int max_locals,
876 bool ret_semantics = false)
878 stacktop = copy->stacktop;
879 stackdepth = copy->stackdepth;
880 subroutine = copy->subroutine;
881 for (int i = 0; i < max_stack; ++i)
882 stack[i] = copy->stack[i];
883 for (int i = 0; i < max_locals; ++i)
885 // See push_jump_merge to understand this case.
887 locals[i] = type (copy->local_changed[i]
889 : unused_by_subroutine_type);
891 locals[i] = copy->locals[i];
892 local_changed[i] = copy->local_changed[i];
894 this_type = copy->this_type;
895 // Don't modify `next'.
898 // Modify this state to reflect entry to an exception handler.
899 void set_exception (type t, int max_stack)
904 for (int i = stacktop; i < max_stack; ++i)
905 stack[i] = unsuitable_type;
908 // Modify this state to reflect entry into a subroutine.
909 void enter_subroutine (int npc, int max_locals)
912 // Mark all items as unchanged. Each subroutine needs to keep
913 // track of its `changed' state independently. In the case of
914 // nested subroutines, this information will be merged back into
915 // parent by the `ret'.
916 for (int i = 0; i < max_locals; ++i)
917 local_changed[i] = false;
920 // Merge STATE_OLD into this state. Destructively modifies this
921 // state. Returns true if the new state was in fact changed.
922 // Will throw an exception if the states are not mergeable.
923 bool merge (state *state_old, bool ret_semantics,
924 int max_locals, _Jv_BytecodeVerifier *verifier)
926 bool changed = false;
928 // Special handling for `this'. If one or the other is
929 // uninitialized, then the merge is uninitialized.
930 if (this_type.isinitialized ())
931 this_type = state_old->this_type;
933 // Merge subroutine states. Here we just keep track of what
934 // subroutine we think we're in. We only check for a merge
935 // (which is invalid) when we see a `ret'.
936 if (subroutine == state_old->subroutine)
940 else if (subroutine == 0)
942 subroutine = state_old->subroutine;
947 // If the subroutines differ, indicate that the state
948 // changed. This is needed to detect when subroutines have
953 // Merge stacks. Special handling for NO_STACK case.
954 if (state_old->stacktop == NO_STACK)
956 // Nothing to do in this case; we don't care about modifying
959 else if (stacktop == NO_STACK)
961 stacktop = state_old->stacktop;
962 stackdepth = state_old->stackdepth;
963 for (int i = 0; i < stacktop; ++i)
964 stack[i] = state_old->stack[i];
967 else if (state_old->stacktop != stacktop)
968 verifier->verify_fail ("stack sizes differ");
971 for (int i = 0; i < state_old->stacktop; ++i)
973 if (stack[i].merge (state_old->stack[i], false, verifier))
978 // Merge local variables.
979 for (int i = 0; i < max_locals; ++i)
981 // If we're not processing a `ret', then we merge every
982 // local variable. If we are processing a `ret', then we
983 // only merge locals which changed in the subroutine. When
984 // processing a `ret', STATE_OLD is the state at the point
985 // of the `ret', and THIS is the state just after the `jsr'.
986 if (! ret_semantics || state_old->local_changed[i])
988 if (locals[i].merge (state_old->locals[i], true, verifier))
990 // Note that we don't call `note_variable' here.
991 // This change doesn't represent a real change to a
992 // local, but rather a merge artifact. If we're in
993 // a subroutine which is called with two
994 // incompatible types in a slot that is unused by
995 // the subroutine, then we don't want to mark that
996 // variable as having been modified.
1001 // If we're in a subroutine, we must compute the union of
1002 // all the changed local variables.
1003 if (state_old->local_changed[i])
1010 // Throw an exception if there is an uninitialized object on the
1011 // stack or in a local variable. EXCEPTION_SEMANTICS controls
1012 // whether we're using backwards-branch or exception-handing
1014 void check_no_uninitialized_objects (int max_locals,
1015 _Jv_BytecodeVerifier *verifier,
1016 bool exception_semantics = false)
1018 if (! exception_semantics)
1020 for (int i = 0; i < stacktop; ++i)
1021 if (stack[i].isreference () && ! stack[i].isinitialized ())
1022 verifier->verify_fail ("uninitialized object on stack");
1025 for (int i = 0; i < max_locals; ++i)
1026 if (locals[i].isreference () && ! locals[i].isinitialized ())
1027 verifier->verify_fail ("uninitialized object in local variable");
1029 check_this_initialized (verifier);
1032 // Ensure that `this' has been initialized.
1033 void check_this_initialized (_Jv_BytecodeVerifier *verifier)
1035 if (this_type.isreference () && ! this_type.isinitialized ())
1036 verifier->verify_fail ("`this' is uninitialized");
1039 // Set type of `this'.
1040 void set_this_type (const type &k)
1045 // Note that a local variable was modified.
1046 void note_variable (int index)
1049 local_changed[index] = true;
1052 // Mark each `new'd object we know of that was allocated at PC as
1054 void set_initialized (int pc, int max_locals)
1056 for (int i = 0; i < stacktop; ++i)
1057 stack[i].set_initialized (pc);
1058 for (int i = 0; i < max_locals; ++i)
1059 locals[i].set_initialized (pc);
1060 this_type.set_initialized (pc);
1063 // Return true if this state is the unmerged result of a `ret'.
1064 bool is_unmerged_ret_state (int max_locals) const
1066 if (stacktop == NO_STACK)
1068 for (int i = 0; i < max_locals; ++i)
1070 if (locals[i].key == unused_by_subroutine_type)
1077 void print (const char *leader, int pc,
1078 int max_stack, int max_locals) const
1080 debug_print ("%s [%4d]: [stack] ", leader, pc);
1082 for (i = 0; i < stacktop; ++i)
1084 for (; i < max_stack; ++i)
1086 debug_print (" [local] ");
1087 for (i = 0; i < max_locals; ++i)
1090 debug_print (local_changed[i] ? "+" : " ");
1092 if (subroutine == 0)
1093 debug_print (" | None");
1095 debug_print (" | %4d", subroutine);
1096 debug_print (" | %p\n", this);
1099 inline void print (const char *, int, int, int) const
1102 #endif /* VERIFY_DEBUG */
1107 if (current_state->stacktop <= 0)
1108 verify_fail ("stack empty");
1109 type r = current_state->stack[--current_state->stacktop];
1110 current_state->stackdepth -= r.depth ();
1111 if (current_state->stackdepth < 0)
1112 verify_fail ("stack empty", start_PC);
1118 type r = pop_raw ();
1120 verify_fail ("narrow pop of wide type");
1126 type r = pop_raw ();
1128 verify_fail ("wide pop of narrow type");
1132 type pop_type (type match)
1135 type t = pop_raw ();
1136 if (! match.compatible (t, this))
1137 verify_fail ("incompatible type on stack");
1141 // Pop a reference which is guaranteed to be initialized. MATCH
1142 // doesn't have to be a reference type; in this case this acts like
1144 type pop_init_ref (type match)
1146 type t = pop_raw ();
1147 if (t.isreference () && ! t.isinitialized ())
1148 verify_fail ("initialized reference required");
1149 else if (! match.compatible (t, this))
1150 verify_fail ("incompatible type on stack");
1154 // Pop a reference type or a return address.
1155 type pop_ref_or_return ()
1157 type t = pop_raw ();
1158 if (! t.isreference () && t.key != return_address_type)
1159 verify_fail ("expected reference or return address on stack");
1163 void push_type (type t)
1165 // If T is a numeric type like short, promote it to int.
1168 int depth = t.depth ();
1169 if (current_state->stackdepth + depth > current_method->max_stack)
1170 verify_fail ("stack overflow");
1171 current_state->stack[current_state->stacktop++] = t;
1172 current_state->stackdepth += depth;
1175 void set_variable (int index, type t)
1177 // If T is a numeric type like short, promote it to int.
1180 int depth = t.depth ();
1181 if (index > current_method->max_locals - depth)
1182 verify_fail ("invalid local variable");
1183 current_state->locals[index] = t;
1184 current_state->note_variable (index);
1188 current_state->locals[index + 1] = continuation_type;
1189 current_state->note_variable (index + 1);
1191 if (index > 0 && current_state->locals[index - 1].iswide ())
1193 current_state->locals[index - 1] = unsuitable_type;
1194 // There's no need to call note_variable here.
1198 type get_variable (int index, type t)
1200 int depth = t.depth ();
1201 if (index > current_method->max_locals - depth)
1202 verify_fail ("invalid local variable");
1203 if (! t.compatible (current_state->locals[index], this))
1204 verify_fail ("incompatible type in local variable");
1207 type t (continuation_type);
1208 if (! current_state->locals[index + 1].compatible (t, this))
1209 verify_fail ("invalid local variable");
1211 return current_state->locals[index];
1214 // Make sure ARRAY is an array type and that its elements are
1215 // compatible with type ELEMENT. Returns the actual element type.
1216 type require_array_type (type array, type element)
1218 // An odd case. Here we just pretend that everything went ok. If
1219 // the requested element type is some kind of reference, return
1220 // the null type instead.
1221 if (array.isnull ())
1222 return element.isreference () ? type (null_type) : element;
1224 if (! array.isarray ())
1225 verify_fail ("array required");
1227 type t = array.element_type (this);
1228 if (! element.compatible (t, this))
1230 // Special case for byte arrays, which must also be boolean
1233 if (element.key == byte_type)
1235 type e2 (boolean_type);
1236 ok = e2.compatible (t, this);
1239 verify_fail ("incompatible array element type");
1242 // Return T and not ELEMENT, because T might be specialized.
1248 if (PC >= current_method->code_length)
1249 verify_fail ("premature end of bytecode");
1250 return (jint) bytecode[PC++] & 0xff;
1255 jint b1 = get_byte ();
1256 jint b2 = get_byte ();
1257 return (jint) ((b1 << 8) | b2) & 0xffff;
1262 jint b1 = get_byte ();
1263 jint b2 = get_byte ();
1264 jshort s = (b1 << 8) | b2;
1270 jint b1 = get_byte ();
1271 jint b2 = get_byte ();
1272 jint b3 = get_byte ();
1273 jint b4 = get_byte ();
1274 return (b1 << 24) | (b2 << 16) | (b3 << 8) | b4;
1277 int compute_jump (int offset)
1279 int npc = start_PC + offset;
1280 if (npc < 0 || npc >= current_method->code_length)
1281 verify_fail ("branch out of range", start_PC);
1285 // Merge the indicated state into the state at the branch target and
1286 // schedule a new PC if there is a change. If RET_SEMANTICS is
1287 // true, then we are merging from a `ret' instruction into the
1288 // instruction after a `jsr'. This is a special case with its own
1289 // modified semantics.
1290 void push_jump_merge (int npc, state *nstate, bool ret_semantics = false)
1292 bool changed = true;
1293 if (states[npc] == NULL)
1295 // There's a weird situation here. If are examining the
1296 // branch that results from a `ret', and there is not yet a
1297 // state available at the branch target (the instruction just
1298 // after the `jsr'), then we have to construct a special kind
1299 // of state at that point for future merging. This special
1300 // state has the type `unused_by_subroutine_type' in each slot
1301 // which was not modified by the subroutine.
1302 states[npc] = new state (nstate, current_method->max_stack,
1303 current_method->max_locals, ret_semantics);
1304 debug_print ("== New state in push_jump_merge\n");
1305 states[npc]->print ("New", npc, current_method->max_stack,
1306 current_method->max_locals);
1310 debug_print ("== Merge states in push_jump_merge\n");
1311 nstate->print ("Frm", start_PC, current_method->max_stack,
1312 current_method->max_locals);
1313 states[npc]->print (" To", npc, current_method->max_stack,
1314 current_method->max_locals);
1315 changed = states[npc]->merge (nstate, ret_semantics,
1316 current_method->max_locals, this);
1317 states[npc]->print ("New", npc, current_method->max_stack,
1318 current_method->max_locals);
1321 if (changed && states[npc]->next == state::INVALID)
1323 // The merge changed the state, and the new PC isn't yet on our
1324 // list of PCs to re-verify.
1325 states[npc]->next = next_verify_pc;
1326 next_verify_pc = npc;
1330 void push_jump (int offset)
1332 int npc = compute_jump (offset);
1334 current_state->check_no_uninitialized_objects (current_method->max_locals, this);
1335 push_jump_merge (npc, current_state);
1338 void push_exception_jump (type t, int pc)
1340 current_state->check_no_uninitialized_objects (current_method->max_locals,
1342 state s (current_state, current_method->max_stack,
1343 current_method->max_locals);
1344 if (current_method->max_stack < 1)
1345 verify_fail ("stack overflow at exception handler");
1346 s.set_exception (t, current_method->max_stack);
1347 push_jump_merge (pc, &s);
1352 int *prev_loc = &next_verify_pc;
1353 int npc = next_verify_pc;
1354 bool skipped = false;
1356 while (npc != state::NO_NEXT)
1358 // If the next available PC is an unmerged `ret' state, then
1359 // we aren't yet ready to handle it. That's because we would
1360 // need all kind of special cases to do so. So instead we
1361 // defer this jump until after we've processed it via a
1362 // fall-through. This has to happen because the instruction
1363 // before this one must be a `jsr'.
1364 if (! states[npc]->is_unmerged_ret_state (current_method->max_locals))
1366 *prev_loc = states[npc]->next;
1367 states[npc]->next = state::INVALID;
1372 prev_loc = &states[npc]->next;
1373 npc = states[npc]->next;
1376 // Note that we might have gotten here even when there are
1377 // remaining states to process. That can happen if we find a
1378 // `jsr' without a `ret'.
1379 return state::NO_NEXT;
1382 void invalidate_pc ()
1384 PC = state::NO_NEXT;
1387 void note_branch_target (int pc, bool is_jsr_target = false)
1389 // Don't check `pc <= PC', because we've advanced PC after
1390 // fetching the target and we haven't yet checked the next
1392 if (pc < PC && ! (flags[pc] & FLAG_INSN_START))
1393 verify_fail ("branch not to instruction start", start_PC);
1394 flags[pc] |= FLAG_BRANCH_TARGET;
1397 // Record the jsr which called this instruction.
1398 subr_info *info = (subr_info *) _Jv_Malloc (sizeof (subr_info));
1400 info->next = jsr_ptrs[pc];
1401 jsr_ptrs[pc] = info;
1405 void skip_padding ()
1407 while ((PC % 4) > 0)
1408 if (get_byte () != 0)
1409 verify_fail ("found nonzero padding byte");
1412 // Return the subroutine to which the instruction at PC belongs.
1413 int get_subroutine (int pc)
1415 if (states[pc] == NULL)
1417 return states[pc]->subroutine;
1420 // Do the work for a `ret' instruction. INDEX is the index into the
1422 void handle_ret_insn (int index)
1424 get_variable (index, return_address_type);
1426 int csub = current_state->subroutine;
1428 verify_fail ("no subroutine");
1430 // Check to see if we've merged subroutines.
1431 subr_entry_info *entry;
1432 for (entry = entry_points; entry != NULL; entry = entry->next)
1434 if (entry->ret_pc == start_PC)
1439 entry = (subr_entry_info *) _Jv_Malloc (sizeof (subr_entry_info));
1441 entry->ret_pc = start_PC;
1442 entry->next = entry_points;
1443 entry_points = entry;
1445 else if (entry->pc != csub)
1446 verify_fail ("subroutines merged");
1448 for (subr_info *subr = jsr_ptrs[csub]; subr != NULL; subr = subr->next)
1450 // Temporarily modify the current state so it looks like we're
1451 // in the enclosing context.
1452 current_state->subroutine = get_subroutine (subr->pc);
1454 current_state->check_no_uninitialized_objects (current_method->max_locals, this);
1455 push_jump_merge (subr->pc, current_state, true);
1458 current_state->subroutine = csub;
1462 // We're in the subroutine SUB, calling a subroutine at DEST. Make
1463 // sure this subroutine isn't already on the stack.
1464 void check_nonrecursive_call (int sub, int dest)
1469 verify_fail ("recursive subroutine call");
1470 for (subr_info *info = jsr_ptrs[sub]; info != NULL; info = info->next)
1471 check_nonrecursive_call (get_subroutine (info->pc), dest);
1474 void handle_jsr_insn (int offset)
1476 int npc = compute_jump (offset);
1479 current_state->check_no_uninitialized_objects (current_method->max_locals, this);
1480 check_nonrecursive_call (current_state->subroutine, npc);
1482 // Modify our state as appropriate for entry into a subroutine.
1483 push_type (return_address_type);
1484 push_jump_merge (npc, current_state);
1486 pop_type (return_address_type);
1488 // On entry to the subroutine, the subroutine number must be set
1489 // and the locals must be marked as cleared. We do this after
1490 // merging state so that we don't erroneously "notice" a variable
1491 // change merely on entry.
1492 states[npc]->enter_subroutine (npc, current_method->max_locals);
1494 // Indicate that we don't know the stack depth of the instruction
1495 // following the `jsr'. The idea here is that we need to merge
1496 // the local variable state across the jsr, but the subroutine
1497 // might change the stack depth, so we can't make any assumptions
1498 // about it. So we have yet another special case. We know that
1499 // at this point PC points to the instruction after the jsr.
1501 // FIXME: what if we have a jsr at the end of the code, but that
1502 // jsr has no corresponding ret? Is this verifiable, or is it
1503 // not? If it is then we need a special case here.
1504 if (PC >= current_method->code_length)
1505 verify_fail ("fell off end");
1507 current_state->stacktop = state::NO_STACK;
1508 push_jump_merge (PC, current_state);
1512 jclass construct_primitive_array_type (type_val prim)
1518 k = JvPrimClass (boolean);
1521 k = JvPrimClass (char);
1524 k = JvPrimClass (float);
1527 k = JvPrimClass (double);
1530 k = JvPrimClass (byte);
1533 k = JvPrimClass (short);
1536 k = JvPrimClass (int);
1539 k = JvPrimClass (long);
1542 // These aren't used here but we call them out to avoid
1545 case unsuitable_type:
1546 case return_address_type:
1547 case continuation_type:
1548 case unused_by_subroutine_type:
1549 case reference_type:
1551 case unresolved_reference_type:
1552 case uninitialized_reference_type:
1553 case uninitialized_unresolved_reference_type:
1555 verify_fail ("unknown type in construct_primitive_array_type");
1557 k = _Jv_GetArrayClass (k, NULL);
1561 // This pass computes the location of branch targets and also
1562 // instruction starts.
1563 void branch_prepass ()
1565 flags = (char *) _Jv_Malloc (current_method->code_length);
1566 jsr_ptrs = (subr_info **) _Jv_Malloc (sizeof (subr_info *)
1567 * current_method->code_length);
1569 for (int i = 0; i < current_method->code_length; ++i)
1575 bool last_was_jsr = false;
1578 while (PC < current_method->code_length)
1580 // Set `start_PC' early so that error checking can have the
1583 flags[PC] |= FLAG_INSN_START;
1585 // If the previous instruction was a jsr, then the next
1586 // instruction is a branch target -- the branch being the
1587 // corresponding `ret'.
1589 note_branch_target (PC);
1590 last_was_jsr = false;
1592 java_opcode opcode = (java_opcode) bytecode[PC++];
1596 case op_aconst_null:
1732 case op_monitorenter:
1733 case op_monitorexit:
1741 case op_arraylength:
1773 case op_invokespecial:
1774 case op_invokestatic:
1775 case op_invokevirtual:
1779 case op_multianewarray:
1785 last_was_jsr = true;
1804 note_branch_target (compute_jump (get_short ()), last_was_jsr);
1807 case op_tableswitch:
1810 note_branch_target (compute_jump (get_int ()));
1811 jint low = get_int ();
1812 jint hi = get_int ();
1814 verify_fail ("invalid tableswitch", start_PC);
1815 for (int i = low; i <= hi; ++i)
1816 note_branch_target (compute_jump (get_int ()));
1820 case op_lookupswitch:
1823 note_branch_target (compute_jump (get_int ()));
1824 int npairs = get_int ();
1826 verify_fail ("too few pairs in lookupswitch", start_PC);
1827 while (npairs-- > 0)
1830 note_branch_target (compute_jump (get_int ()));
1835 case op_invokeinterface:
1843 opcode = (java_opcode) get_byte ();
1845 if (opcode == op_iinc)
1851 last_was_jsr = true;
1854 note_branch_target (compute_jump (get_int ()), last_was_jsr);
1857 // These are unused here, but we call them out explicitly
1858 // so that -Wswitch-enum doesn't complain.
1864 case op_putstatic_1:
1865 case op_putstatic_2:
1866 case op_putstatic_4:
1867 case op_putstatic_8:
1868 case op_putstatic_a:
1870 case op_getfield_2s:
1871 case op_getfield_2u:
1875 case op_getstatic_1:
1876 case op_getstatic_2s:
1877 case op_getstatic_2u:
1878 case op_getstatic_4:
1879 case op_getstatic_8:
1880 case op_getstatic_a:
1882 verify_fail ("unrecognized instruction in branch_prepass",
1886 // See if any previous branch tried to branch to the middle of
1887 // this instruction.
1888 for (int pc = start_PC + 1; pc < PC; ++pc)
1890 if ((flags[pc] & FLAG_BRANCH_TARGET))
1891 verify_fail ("branch to middle of instruction", pc);
1895 // Verify exception handlers.
1896 for (int i = 0; i < current_method->exc_count; ++i)
1898 if (! (flags[exception[i].handler_pc.i] & FLAG_INSN_START))
1899 verify_fail ("exception handler not at instruction start",
1900 exception[i].handler_pc.i);
1901 if (! (flags[exception[i].start_pc.i] & FLAG_INSN_START))
1902 verify_fail ("exception start not at instruction start",
1903 exception[i].start_pc.i);
1904 if (exception[i].end_pc.i != current_method->code_length
1905 && ! (flags[exception[i].end_pc.i] & FLAG_INSN_START))
1906 verify_fail ("exception end not at instruction start",
1907 exception[i].end_pc.i);
1909 flags[exception[i].handler_pc.i] |= FLAG_BRANCH_TARGET;
1913 void check_pool_index (int index)
1915 if (index < 0 || index >= current_class->constants.size)
1916 verify_fail ("constant pool index out of range", start_PC);
1919 type check_class_constant (int index)
1921 check_pool_index (index);
1922 _Jv_Constants *pool = ¤t_class->constants;
1923 if (pool->tags[index] == JV_CONSTANT_ResolvedClass)
1924 return type (pool->data[index].clazz);
1925 else if (pool->tags[index] == JV_CONSTANT_Class)
1926 return type (pool->data[index].utf8);
1927 verify_fail ("expected class constant", start_PC);
1930 type check_constant (int index)
1932 check_pool_index (index);
1933 _Jv_Constants *pool = ¤t_class->constants;
1934 if (pool->tags[index] == JV_CONSTANT_ResolvedString
1935 || pool->tags[index] == JV_CONSTANT_String)
1936 return type (&java::lang::String::class$);
1937 else if (pool->tags[index] == JV_CONSTANT_Integer)
1938 return type (int_type);
1939 else if (pool->tags[index] == JV_CONSTANT_Float)
1940 return type (float_type);
1941 verify_fail ("String, int, or float constant expected", start_PC);
1944 type check_wide_constant (int index)
1946 check_pool_index (index);
1947 _Jv_Constants *pool = ¤t_class->constants;
1948 if (pool->tags[index] == JV_CONSTANT_Long)
1949 return type (long_type);
1950 else if (pool->tags[index] == JV_CONSTANT_Double)
1951 return type (double_type);
1952 verify_fail ("long or double constant expected", start_PC);
1955 // Helper for both field and method. These are laid out the same in
1956 // the constant pool.
1957 type handle_field_or_method (int index, int expected,
1958 _Jv_Utf8Const **name,
1959 _Jv_Utf8Const **fmtype)
1961 check_pool_index (index);
1962 _Jv_Constants *pool = ¤t_class->constants;
1963 if (pool->tags[index] != expected)
1964 verify_fail ("didn't see expected constant", start_PC);
1965 // Once we know we have a Fieldref or Methodref we assume that it
1966 // is correctly laid out in the constant pool. I think the code
1967 // in defineclass.cc guarantees this.
1968 _Jv_ushort class_index, name_and_type_index;
1969 _Jv_loadIndexes (&pool->data[index],
1971 name_and_type_index);
1972 _Jv_ushort name_index, desc_index;
1973 _Jv_loadIndexes (&pool->data[name_and_type_index],
1974 name_index, desc_index);
1976 *name = pool->data[name_index].utf8;
1977 *fmtype = pool->data[desc_index].utf8;
1979 return check_class_constant (class_index);
1982 // Return field's type, compute class' type if requested.
1983 type check_field_constant (int index, type *class_type = NULL)
1985 _Jv_Utf8Const *name, *field_type;
1986 type ct = handle_field_or_method (index,
1987 JV_CONSTANT_Fieldref,
1988 &name, &field_type);
1991 if (field_type->data[0] == '[' || field_type->data[0] == 'L')
1992 return type (field_type);
1993 return get_type_val_for_signature (field_type->data[0]);
1996 type check_method_constant (int index, bool is_interface,
1997 _Jv_Utf8Const **method_name,
1998 _Jv_Utf8Const **method_signature)
2000 return handle_field_or_method (index,
2002 ? JV_CONSTANT_InterfaceMethodref
2003 : JV_CONSTANT_Methodref),
2004 method_name, method_signature);
2007 type get_one_type (char *&p)
2025 _Jv_Utf8Const *name = make_utf8_const (start, p - start);
2029 // Casting to jchar here is ok since we are looking at an ASCII
2031 type_val rt = get_type_val_for_signature (jchar (v));
2033 if (arraycount == 0)
2035 // Callers of this function eventually push their arguments on
2036 // the stack. So, promote them here.
2037 return type (rt).promote ();
2040 jclass k = construct_primitive_array_type (rt);
2041 while (--arraycount > 0)
2042 k = _Jv_GetArrayClass (k, NULL);
2046 void compute_argument_types (_Jv_Utf8Const *signature,
2049 char *p = signature->data;
2055 types[i++] = get_one_type (p);
2058 type compute_return_type (_Jv_Utf8Const *signature)
2060 char *p = signature->data;
2064 return get_one_type (p);
2067 void check_return_type (type onstack)
2069 type rt = compute_return_type (current_method->self->signature);
2070 if (! rt.compatible (onstack, this))
2071 verify_fail ("incompatible return type");
2074 // Initialize the stack for the new method. Returns true if this
2075 // method is an instance initializer.
2076 bool initialize_stack ()
2079 bool is_init = false;
2081 using namespace java::lang::reflect;
2082 if (! Modifier::isStatic (current_method->self->accflags))
2084 type kurr (current_class);
2085 if (_Jv_equalUtf8Consts (current_method->self->name, gcj::init_name))
2087 kurr.set_uninitialized (type::SELF, this);
2090 set_variable (0, kurr);
2091 current_state->set_this_type (kurr);
2095 // We have to handle wide arguments specially here.
2096 int arg_count = _Jv_count_arguments (current_method->self->signature);
2097 type arg_types[arg_count];
2098 compute_argument_types (current_method->self->signature, arg_types);
2099 for (int i = 0; i < arg_count; ++i)
2101 set_variable (var, arg_types[i]);
2103 if (arg_types[i].iswide ())
2110 void verify_instructions_0 ()
2112 current_state = new state (current_method->max_stack,
2113 current_method->max_locals);
2118 // True if we are verifying an instance initializer.
2119 bool this_is_init = initialize_stack ();
2121 states = (state **) _Jv_Malloc (sizeof (state *)
2122 * current_method->code_length);
2123 for (int i = 0; i < current_method->code_length; ++i)
2126 next_verify_pc = state::NO_NEXT;
2130 // If the PC was invalidated, get a new one from the work list.
2131 if (PC == state::NO_NEXT)
2134 if (PC == state::INVALID)
2135 verify_fail ("can't happen: saw state::INVALID");
2136 if (PC == state::NO_NEXT)
2138 debug_print ("== State pop from pending list\n");
2139 // Set up the current state.
2140 current_state->copy (states[PC], current_method->max_stack,
2141 current_method->max_locals);
2145 // Control can't fall off the end of the bytecode. We
2146 // only need to check this in the fall-through case,
2147 // because branch bounds are checked when they are
2149 if (PC >= current_method->code_length)
2150 verify_fail ("fell off end");
2152 // We only have to do this checking in the situation where
2153 // control flow falls through from the previous
2154 // instruction. Otherwise merging is done at the time we
2156 if (states[PC] != NULL)
2158 // We've already visited this instruction. So merge
2159 // the states together. If this yields no change then
2160 // we don't have to re-verify. However, if the new
2161 // state is an the result of an unmerged `ret', we
2162 // must continue through it.
2163 debug_print ("== Fall through merge\n");
2164 states[PC]->print ("Old", PC, current_method->max_stack,
2165 current_method->max_locals);
2166 current_state->print ("Cur", PC, current_method->max_stack,
2167 current_method->max_locals);
2168 if (! current_state->merge (states[PC], false,
2169 current_method->max_locals, this)
2170 && ! states[PC]->is_unmerged_ret_state (current_method->max_locals))
2172 debug_print ("== Fall through optimization\n");
2176 // Save a copy of it for later.
2177 states[PC]->copy (current_state, current_method->max_stack,
2178 current_method->max_locals);
2179 current_state->print ("New", PC, current_method->max_stack,
2180 current_method->max_locals);
2184 // We only have to keep saved state at branch targets. If
2185 // we're at a branch target and the state here hasn't been set
2186 // yet, we set it now.
2187 if (states[PC] == NULL && (flags[PC] & FLAG_BRANCH_TARGET))
2189 states[PC] = new state (current_state, current_method->max_stack,
2190 current_method->max_locals);
2193 // Set this before handling exceptions so that debug output is
2197 // Update states for all active exception handlers. Ordinarily
2198 // there are not many exception handlers. So we simply run
2199 // through them all.
2200 for (int i = 0; i < current_method->exc_count; ++i)
2202 if (PC >= exception[i].start_pc.i && PC < exception[i].end_pc.i)
2204 type handler (&java::lang::Throwable::class$);
2205 if (exception[i].handler_type.i != 0)
2206 handler = check_class_constant (exception[i].handler_type.i);
2207 push_exception_jump (handler, exception[i].handler_pc.i);
2211 current_state->print (" ", PC, current_method->max_stack,
2212 current_method->max_locals);
2213 java_opcode opcode = (java_opcode) bytecode[PC++];
2219 case op_aconst_null:
2220 push_type (null_type);
2230 push_type (int_type);
2235 push_type (long_type);
2241 push_type (float_type);
2246 push_type (double_type);
2251 push_type (int_type);
2256 push_type (int_type);
2260 push_type (check_constant (get_byte ()));
2263 push_type (check_constant (get_ushort ()));
2266 push_type (check_wide_constant (get_ushort ()));
2270 push_type (get_variable (get_byte (), int_type));
2273 push_type (get_variable (get_byte (), long_type));
2276 push_type (get_variable (get_byte (), float_type));
2279 push_type (get_variable (get_byte (), double_type));
2282 push_type (get_variable (get_byte (), reference_type));
2289 push_type (get_variable (opcode - op_iload_0, int_type));
2295 push_type (get_variable (opcode - op_lload_0, long_type));
2301 push_type (get_variable (opcode - op_fload_0, float_type));
2307 push_type (get_variable (opcode - op_dload_0, double_type));
2313 push_type (get_variable (opcode - op_aload_0, reference_type));
2316 pop_type (int_type);
2317 push_type (require_array_type (pop_init_ref (reference_type),
2321 pop_type (int_type);
2322 push_type (require_array_type (pop_init_ref (reference_type),
2326 pop_type (int_type);
2327 push_type (require_array_type (pop_init_ref (reference_type),
2331 pop_type (int_type);
2332 push_type (require_array_type (pop_init_ref (reference_type),
2336 pop_type (int_type);
2337 push_type (require_array_type (pop_init_ref (reference_type),
2341 pop_type (int_type);
2342 require_array_type (pop_init_ref (reference_type), byte_type);
2343 push_type (int_type);
2346 pop_type (int_type);
2347 require_array_type (pop_init_ref (reference_type), char_type);
2348 push_type (int_type);
2351 pop_type (int_type);
2352 require_array_type (pop_init_ref (reference_type), short_type);
2353 push_type (int_type);
2356 set_variable (get_byte (), pop_type (int_type));
2359 set_variable (get_byte (), pop_type (long_type));
2362 set_variable (get_byte (), pop_type (float_type));
2365 set_variable (get_byte (), pop_type (double_type));
2368 set_variable (get_byte (), pop_ref_or_return ());
2374 set_variable (opcode - op_istore_0, pop_type (int_type));
2380 set_variable (opcode - op_lstore_0, pop_type (long_type));
2386 set_variable (opcode - op_fstore_0, pop_type (float_type));
2392 set_variable (opcode - op_dstore_0, pop_type (double_type));
2398 set_variable (opcode - op_astore_0, pop_ref_or_return ());
2401 pop_type (int_type);
2402 pop_type (int_type);
2403 require_array_type (pop_init_ref (reference_type), int_type);
2406 pop_type (long_type);
2407 pop_type (int_type);
2408 require_array_type (pop_init_ref (reference_type), long_type);
2411 pop_type (float_type);
2412 pop_type (int_type);
2413 require_array_type (pop_init_ref (reference_type), float_type);
2416 pop_type (double_type);
2417 pop_type (int_type);
2418 require_array_type (pop_init_ref (reference_type), double_type);
2421 pop_type (reference_type);
2422 pop_type (int_type);
2423 require_array_type (pop_init_ref (reference_type), reference_type);
2426 pop_type (int_type);
2427 pop_type (int_type);
2428 require_array_type (pop_init_ref (reference_type), byte_type);
2431 pop_type (int_type);
2432 pop_type (int_type);
2433 require_array_type (pop_init_ref (reference_type), char_type);
2436 pop_type (int_type);
2437 pop_type (int_type);
2438 require_array_type (pop_init_ref (reference_type), short_type);
2465 type t2 = pop_raw ();
2480 type t = pop_raw ();
2495 type t1 = pop_raw ();
2512 type t1 = pop_raw ();
2515 type t2 = pop_raw ();
2533 type t3 = pop_raw ();
2571 pop_type (int_type);
2572 push_type (pop_type (int_type));
2582 pop_type (long_type);
2583 push_type (pop_type (long_type));
2588 pop_type (int_type);
2589 push_type (pop_type (long_type));
2596 pop_type (float_type);
2597 push_type (pop_type (float_type));
2604 pop_type (double_type);
2605 push_type (pop_type (double_type));
2611 push_type (pop_type (int_type));
2614 push_type (pop_type (long_type));
2617 push_type (pop_type (float_type));
2620 push_type (pop_type (double_type));
2623 get_variable (get_byte (), int_type);
2627 pop_type (int_type);
2628 push_type (long_type);
2631 pop_type (int_type);
2632 push_type (float_type);
2635 pop_type (int_type);
2636 push_type (double_type);
2639 pop_type (long_type);
2640 push_type (int_type);
2643 pop_type (long_type);
2644 push_type (float_type);
2647 pop_type (long_type);
2648 push_type (double_type);
2651 pop_type (float_type);
2652 push_type (int_type);
2655 pop_type (float_type);
2656 push_type (long_type);
2659 pop_type (float_type);
2660 push_type (double_type);
2663 pop_type (double_type);
2664 push_type (int_type);
2667 pop_type (double_type);
2668 push_type (long_type);
2671 pop_type (double_type);
2672 push_type (float_type);
2675 pop_type (long_type);
2676 pop_type (long_type);
2677 push_type (int_type);
2681 pop_type (float_type);
2682 pop_type (float_type);
2683 push_type (int_type);
2687 pop_type (double_type);
2688 pop_type (double_type);
2689 push_type (int_type);
2697 pop_type (int_type);
2698 push_jump (get_short ());
2706 pop_type (int_type);
2707 pop_type (int_type);
2708 push_jump (get_short ());
2712 pop_type (reference_type);
2713 pop_type (reference_type);
2714 push_jump (get_short ());
2717 push_jump (get_short ());
2721 handle_jsr_insn (get_short ());
2724 handle_ret_insn (get_byte ());
2726 case op_tableswitch:
2728 pop_type (int_type);
2730 push_jump (get_int ());
2731 jint low = get_int ();
2732 jint high = get_int ();
2733 // Already checked LOW -vs- HIGH.
2734 for (int i = low; i <= high; ++i)
2735 push_jump (get_int ());
2740 case op_lookupswitch:
2742 pop_type (int_type);
2744 push_jump (get_int ());
2745 jint npairs = get_int ();
2746 // Already checked NPAIRS >= 0.
2748 for (int i = 0; i < npairs; ++i)
2750 jint key = get_int ();
2751 if (i > 0 && key <= lastkey)
2752 verify_fail ("lookupswitch pairs unsorted", start_PC);
2754 push_jump (get_int ());
2760 check_return_type (pop_type (int_type));
2764 check_return_type (pop_type (long_type));
2768 check_return_type (pop_type (float_type));
2772 check_return_type (pop_type (double_type));
2776 check_return_type (pop_init_ref (reference_type));
2780 // We only need to check this when the return type is
2781 // void, because all instance initializers return void.
2783 current_state->check_this_initialized (this);
2784 check_return_type (void_type);
2788 push_type (check_field_constant (get_ushort ()));
2791 pop_type (check_field_constant (get_ushort ()));
2796 type field = check_field_constant (get_ushort (), &klass);
2804 type field = check_field_constant (get_ushort (), &klass);
2807 // We have an obscure special case here: we can use
2808 // `putfield' on a field declared in this class, even if
2809 // `this' has not yet been initialized.
2810 if (! current_state->this_type.isinitialized ()
2811 && current_state->this_type.pc == type::SELF)
2812 klass.set_uninitialized (type::SELF, this);
2817 case op_invokevirtual:
2818 case op_invokespecial:
2819 case op_invokestatic:
2820 case op_invokeinterface:
2822 _Jv_Utf8Const *method_name, *method_signature;
2824 = check_method_constant (get_ushort (),
2825 opcode == op_invokeinterface,
2828 // NARGS is only used when we're processing
2829 // invokeinterface. It is simplest for us to compute it
2830 // here and then verify it later.
2832 if (opcode == op_invokeinterface)
2834 nargs = get_byte ();
2835 if (get_byte () != 0)
2836 verify_fail ("invokeinterface dummy byte is wrong");
2839 bool is_init = false;
2840 if (_Jv_equalUtf8Consts (method_name, gcj::init_name))
2843 if (opcode != op_invokespecial)
2844 verify_fail ("can't invoke <init>");
2846 else if (method_name->data[0] == '<')
2847 verify_fail ("can't invoke method starting with `<'");
2849 // Pop arguments and check types.
2850 int arg_count = _Jv_count_arguments (method_signature);
2851 type arg_types[arg_count];
2852 compute_argument_types (method_signature, arg_types);
2853 for (int i = arg_count - 1; i >= 0; --i)
2855 // This is only used for verifying the byte for
2857 nargs -= arg_types[i].depth ();
2858 pop_init_ref (arg_types[i]);
2861 if (opcode == op_invokeinterface
2863 verify_fail ("wrong argument count for invokeinterface");
2865 if (opcode != op_invokestatic)
2867 type t = class_type;
2870 // In this case the PC doesn't matter.
2871 t.set_uninitialized (type::UNINIT, this);
2873 type raw = pop_raw ();
2875 if (! is_init && ! raw.isinitialized ())
2877 // This is a failure.
2879 else if (is_init && raw.isnull ())
2883 else if (t.compatible (raw, this))
2887 else if (opcode == op_invokeinterface)
2889 // This is a hack. We might have merged two
2890 // items and gotten `Object'. This can happen
2891 // because we don't keep track of where merges
2892 // come from. This is safe as long as the
2893 // interpreter checks interfaces at runtime.
2894 type obj (&java::lang::Object::class$);
2895 ok = raw.compatible (obj, this);
2899 verify_fail ("incompatible type on stack");
2902 current_state->set_initialized (raw.get_pc (),
2903 current_method->max_locals);
2906 type rt = compute_return_type (method_signature);
2914 type t = check_class_constant (get_ushort ());
2915 if (t.isarray () || t.isinterface (this) || t.isabstract (this))
2916 verify_fail ("type is array, interface, or abstract");
2917 t.set_uninitialized (start_PC, this);
2924 int atype = get_byte ();
2925 // We intentionally have chosen constants to make this
2927 if (atype < boolean_type || atype > long_type)
2928 verify_fail ("type not primitive", start_PC);
2929 pop_type (int_type);
2930 push_type (construct_primitive_array_type (type_val (atype)));
2934 pop_type (int_type);
2935 push_type (check_class_constant (get_ushort ()).to_array (this));
2937 case op_arraylength:
2939 type t = pop_init_ref (reference_type);
2940 if (! t.isarray () && ! t.isnull ())
2941 verify_fail ("array type expected");
2942 push_type (int_type);
2946 pop_type (type (&java::lang::Throwable::class$));
2950 pop_init_ref (reference_type);
2951 push_type (check_class_constant (get_ushort ()));
2954 pop_init_ref (reference_type);
2955 check_class_constant (get_ushort ());
2956 push_type (int_type);
2958 case op_monitorenter:
2959 pop_init_ref (reference_type);
2961 case op_monitorexit:
2962 pop_init_ref (reference_type);
2966 switch (get_byte ())
2969 push_type (get_variable (get_ushort (), int_type));
2972 push_type (get_variable (get_ushort (), long_type));
2975 push_type (get_variable (get_ushort (), float_type));
2978 push_type (get_variable (get_ushort (), double_type));
2981 push_type (get_variable (get_ushort (), reference_type));
2984 set_variable (get_ushort (), pop_type (int_type));
2987 set_variable (get_ushort (), pop_type (long_type));
2990 set_variable (get_ushort (), pop_type (float_type));
2993 set_variable (get_ushort (), pop_type (double_type));
2996 set_variable (get_ushort (), pop_init_ref (reference_type));
2999 handle_ret_insn (get_short ());
3002 get_variable (get_ushort (), int_type);
3006 verify_fail ("unrecognized wide instruction", start_PC);
3010 case op_multianewarray:
3012 type atype = check_class_constant (get_ushort ());
3013 int dim = get_byte ();
3015 verify_fail ("too few dimensions to multianewarray", start_PC);
3016 atype.verify_dimensions (dim, this);
3017 for (int i = 0; i < dim; ++i)
3018 pop_type (int_type);
3024 pop_type (reference_type);
3025 push_jump (get_short ());
3028 push_jump (get_int ());
3032 handle_jsr_insn (get_int ());
3035 // These are unused here, but we call them out explicitly
3036 // so that -Wswitch-enum doesn't complain.
3042 case op_putstatic_1:
3043 case op_putstatic_2:
3044 case op_putstatic_4:
3045 case op_putstatic_8:
3046 case op_putstatic_a:
3048 case op_getfield_2s:
3049 case op_getfield_2u:
3053 case op_getstatic_1:
3054 case op_getstatic_2s:
3055 case op_getstatic_2u:
3056 case op_getstatic_4:
3057 case op_getstatic_8:
3058 case op_getstatic_a:
3060 // Unrecognized opcode.
3061 verify_fail ("unrecognized instruction in verify_instructions_0",
3067 __attribute__ ((__noreturn__)) void verify_fail (char *s, jint pc = -1)
3069 using namespace java::lang;
3070 StringBuffer *buf = new StringBuffer ();
3072 buf->append (JvNewStringLatin1 ("verification failed"));
3077 buf->append (JvNewStringLatin1 (" at PC "));
3081 _Jv_InterpMethod *method = current_method;
3082 buf->append (JvNewStringLatin1 (" in "));
3083 buf->append (current_class->getName());
3084 buf->append ((jchar) ':');
3085 buf->append (JvNewStringUTF (method->get_method()->name->data));
3086 buf->append ((jchar) '(');
3087 buf->append (JvNewStringUTF (method->get_method()->signature->data));
3088 buf->append ((jchar) ')');
3090 buf->append (JvNewStringLatin1 (": "));
3091 buf->append (JvNewStringLatin1 (s));
3092 throw new java::lang::VerifyError (buf->toString ());
3097 void verify_instructions ()
3100 verify_instructions_0 ();
3103 _Jv_BytecodeVerifier (_Jv_InterpMethod *m)
3105 // We just print the text as utf-8. This is just for debugging
3107 debug_print ("--------------------------------\n");
3108 debug_print ("-- Verifying method `%s'\n", m->self->name->data);
3111 bytecode = m->bytecode ();
3112 exception = m->exceptions ();
3113 current_class = m->defining_class;
3119 entry_points = NULL;
3122 ~_Jv_BytecodeVerifier ()
3131 for (int i = 0; i < current_method->code_length; ++i)
3133 if (jsr_ptrs[i] != NULL)
3135 subr_info *info = jsr_ptrs[i];
3136 while (info != NULL)
3138 subr_info *next = info->next;
3144 _Jv_Free (jsr_ptrs);
3147 while (utf8_list != NULL)
3149 linked_utf8 *n = utf8_list->next;
3150 _Jv_Free (utf8_list->val);
3151 _Jv_Free (utf8_list);
3155 while (entry_points != NULL)
3157 subr_entry_info *next = entry_points->next;
3158 _Jv_Free (entry_points);
3159 entry_points = next;
3165 _Jv_VerifyMethod (_Jv_InterpMethod *meth)
3167 _Jv_BytecodeVerifier v (meth);
3168 v.verify_instructions ();
3170 #endif /* INTERPRETER */