-// defineclass.cc - defining a class from .class format.
+// verify.cc - verify bytecode
-/* Copyright (C) 2001 Free Software Foundation
+/* Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation
This file is part of libgcj.
Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
details. */
-// Writte by Tom Tromey <tromey@redhat.com>
+// Written by Tom Tromey <tromey@redhat.com>
+
+// Define VERIFY_DEBUG to enable debugging output.
#include <config.h>
+#include <string.h>
+
#include <jvm.h>
#include <gcj/cni.h>
#include <java-insns.h>
#include <java-interp.h>
+// On Solaris 10/x86, <signal.h> indirectly includes <ia32/sys/reg.h>, which
+// defines PC since g++ predefines __EXTENSIONS__. Undef here to avoid clash
+// with PC member of class _Jv_BytecodeVerifier below.
+#undef PC
+
#ifdef INTERPRETER
#include <java/lang/Class.h>
#include <java/lang/Throwable.h>
#include <java/lang/reflect/Modifier.h>
#include <java/lang/StringBuffer.h>
+#include <java/lang/NoClassDefFoundError.h>
+#ifdef VERIFY_DEBUG
+#include <stdio.h>
+#endif /* VERIFY_DEBUG */
-// TO DO
-// * read more about when classes must be loaded
-// * class loader madness
-// * Lots and lots of debugging and testing
-// * type representation is still ugly. look for the big switches
-// * at least one GC problem :-(
+// This is used to mark states which are not scheduled for
+// verification.
+#define INVALID_STATE ((state *) -1)
-// This is global because __attribute__ doesn't seem to work on static
-// methods.
-static void verify_fail (char *msg, jint pc = -1)
- __attribute__ ((__noreturn__));
+static void debug_print (const char *fmt, ...)
+ __attribute__ ((format (printf, 1, 2)));
+static inline void
+debug_print (MAYBE_UNUSED const char *fmt, ...)
+{
+#ifdef VERIFY_DEBUG
+ va_list ap;
+ va_start (ap, fmt);
+ vfprintf (stderr, fmt, ap);
+ va_end (ap);
+#endif /* VERIFY_DEBUG */
+}
+
+// This started as a fairly ordinary verifier, and for the most part
+// it remains so. It works in the obvious way, by modeling the effect
+// of each opcode as it is encountered. For most opcodes, this is a
+// straightforward operation.
+//
+// This verifier does not do type merging. It used to, but this
+// results in difficulty verifying some relatively simple code
+// involving interfaces, and it pushed some verification work into the
+// interpreter.
+//
+// Instead of merging reference types, when we reach a point where two
+// flows of control merge, we simply keep the union of reference types
+// from each branch. Then, when we need to verify a fact about a
+// reference on the stack (e.g., that it is compatible with the
+// argument type of a method), we check to ensure that all possible
+// types satisfy the requirement.
+//
+// Another area this verifier differs from the norm is in its handling
+// of subroutines. The JVM specification has some confusing things to
+// say about subroutines. For instance, it makes claims about not
+// allowing subroutines to merge and it rejects recursive subroutines.
+// For the most part these are red herrings; we used to try to follow
+// these things but they lead to problems. For example, the notion of
+// "being in a subroutine" is not well-defined: is an exception
+// handler in a subroutine? If you never execute the `ret' but
+// instead `goto 1' do you remain in the subroutine?
+//
+// For clarity on what is really required for type safety, read
+// "Simple Verification Technique for Complex Java Bytecode
+// Subroutines" by Alessandro Coglio. Among other things this paper
+// shows that recursive subroutines are not harmful to type safety.
+// We implement something similar to what he proposes. Note that this
+// means that this verifier will accept code that is rejected by some
+// other verifiers.
+//
+// For those not wanting to read the paper, the basic observation is
+// that we can maintain split states in subroutines. We maintain one
+// state for each calling `jsr'. In other words, we re-verify a
+// subroutine once for each caller, using the exact types held by the
+// callers (as opposed to the old approach of merging types and
+// keeping a bitmap registering what did or did not change). This
+// approach lets us continue to verify correctly even when a
+// subroutine is exited via `goto' or `athrow' and not `ret'.
+//
+// In some other areas the JVM specification is (mildly) incorrect,
+// so we diverge. For instance, you cannot
+// violate type safety by allocating an object with `new' and then
+// failing to initialize it, no matter how one branches or where one
+// stores the uninitialized reference. See "Improving the official
+// specification of Java bytecode verification" by Alessandro Coglio.
+//
+// Note that there's no real point in enforcing that padding bytes or
+// the mystery byte of invokeinterface must be 0, but we do that
+// regardless.
+//
+// The verifier is currently neither completely lazy nor eager when it
+// comes to loading classes. It tries to represent types by name when
+// possible, and then loads them when it needs to verify a fact about
+// the type. Checking types by name is valid because we only use
+// names which come from the current class' constant pool. Since all
+// such names are looked up using the same class loader, there is no
+// danger that we might be fooled into comparing different types with
+// the same name.
+//
+// In the future we plan to allow for a completely lazy mode of
+// operation, where the verifier will construct a list of type
+// assertions to be checked later.
+//
+// Some test cases for the verifier live in the "verify" module of the
+// Mauve test suite. However, some of these are presently
+// (2004-01-20) believed to be incorrect. (More precisely the notion
+// of "correct" is not well-defined, and this verifier differs from
+// others while remaining type-safe.) Some other tests live in the
+// libgcj test suite.
class _Jv_BytecodeVerifier
{
private:
static const int FLAG_INSN_START = 1;
static const int FLAG_BRANCH_TARGET = 2;
- static const int FLAG_JSR_TARGET = 4;
struct state;
struct type;
- struct subr_info;
+ struct linked_utf8;
+ struct ref_intersection;
+
+ template<typename T>
+ struct linked
+ {
+ T *val;
+ linked<T> *next;
+ };
// The current PC.
int PC;
// The current state of the stack, locals, etc.
state *current_state;
- // We store the state at branch targets, for merging. This holds
- // such states.
- state **states;
+ // At each branch target we keep a linked list of all the states we
+ // can process at that point. We'll only have multiple states at a
+ // given PC if they both have different return-address types in the
+ // same stack or local slot. This array is indexed by PC and holds
+ // the list of all such states.
+ linked<state> **states;
- // We keep a linked list of all the PCs which we must reverify.
- // The link is done using the PC values. This is the head of the
- // list.
- int next_verify_pc;
+ // We keep a linked list of all the states which we must reverify.
+ // This is the head of the list.
+ state *next_verify_state;
// We keep some flags for each instruction. The values are the
- // FLAG_* constants defined above.
+ // FLAG_* constants defined above. This is an array indexed by PC.
char *flags;
- // We need to keep track of which instructions can call a given
- // subroutine. FIXME: this is inefficient. We keep a linked list
- // of all calling `jsr's at at each jsr target.
- subr_info **jsr_ptrs;
-
- // The current top of the stack, in terms of slots.
- int stacktop;
- // The current depth of the stack. This will be larger than
- // STACKTOP when wide types are on the stack.
- int stackdepth;
-
// The bytecode itself.
unsigned char *bytecode;
// The exceptions.
// This method.
_Jv_InterpMethod *current_method;
+ // A linked list of utf8 objects we allocate.
+ linked<_Jv_Utf8Const> *utf8_list;
+
+ // A linked list of all ref_intersection objects we allocate.
+ ref_intersection *isect_list;
+
+ // Create a new Utf-8 constant and return it. We do this to avoid
+ // having our Utf-8 constants prematurely collected.
+ _Jv_Utf8Const *make_utf8_const (char *s, int len)
+ {
+ linked<_Jv_Utf8Const> *lu = (linked<_Jv_Utf8Const> *)
+ _Jv_Malloc (sizeof (linked<_Jv_Utf8Const>)
+ + _Jv_Utf8Const::space_needed(s, len));
+ _Jv_Utf8Const *r = (_Jv_Utf8Const *) (lu + 1);
+ r->init(s, len);
+ lu->val = r;
+ lu->next = utf8_list;
+ utf8_list = lu;
+
+ return r;
+ }
+
+ __attribute__ ((__noreturn__)) void verify_fail (const char *s, jint pc = -1)
+ {
+ using namespace java::lang;
+ StringBuffer *buf = new StringBuffer ();
+
+ buf->append (JvNewStringLatin1 ("verification failed"));
+ if (pc == -1)
+ pc = start_PC;
+ if (pc != -1)
+ {
+ buf->append (JvNewStringLatin1 (" at PC "));
+ buf->append (pc);
+ }
+
+ _Jv_InterpMethod *method = current_method;
+ buf->append (JvNewStringLatin1 (" in "));
+ buf->append (current_class->getName());
+ buf->append ((jchar) ':');
+ buf->append (method->get_method()->name->toString());
+ buf->append ((jchar) '(');
+ buf->append (method->get_method()->signature->toString());
+ buf->append ((jchar) ')');
+
+ buf->append (JvNewStringLatin1 (": "));
+ buf->append (JvNewStringLatin1 (s));
+ throw new java::lang::VerifyError (buf->toString ());
+ }
+
// This enum holds a list of tags for all the different types we
// need to handle. Reference types are treated specially by the
// type class.
// to indicate an unusable value.
unsuitable_type,
return_address_type,
+ // This is the second word of a two-word value, i.e., a double or
+ // a long.
continuation_type,
// Everything after `reference_type' must be a reference type.
reference_type,
null_type,
- unresolved_reference_type,
- uninitialized_reference_type,
- uninitialized_unresolved_reference_type
+ uninitialized_reference_type
+ };
+
+ // This represents a merged class type. Some verifiers (including
+ // earlier versions of this one) will compute the intersection of
+ // two class types when merging states. However, this loses
+ // critical information about interfaces implemented by the various
+ // classes. So instead we keep track of all the actual classes that
+ // have been merged.
+ struct ref_intersection
+ {
+ // Whether or not this type has been resolved.
+ bool is_resolved;
+
+ // Actual type data.
+ union
+ {
+ // For a resolved reference type, this is a pointer to the class.
+ jclass klass;
+ // For other reference types, this it the name of the class.
+ _Jv_Utf8Const *name;
+ } data;
+
+ // Link to the next reference in the intersection.
+ ref_intersection *ref_next;
+
+ // This is used to keep track of all the allocated
+ // ref_intersection objects, so we can free them.
+ // FIXME: we should allocate these in chunks.
+ ref_intersection *alloc_next;
+
+ ref_intersection (jclass klass, _Jv_BytecodeVerifier *verifier)
+ : ref_next (NULL)
+ {
+ is_resolved = true;
+ data.klass = klass;
+ alloc_next = verifier->isect_list;
+ verifier->isect_list = this;
+ }
+
+ ref_intersection (_Jv_Utf8Const *name, _Jv_BytecodeVerifier *verifier)
+ : ref_next (NULL)
+ {
+ is_resolved = false;
+ data.name = name;
+ alloc_next = verifier->isect_list;
+ verifier->isect_list = this;
+ }
+
+ ref_intersection (ref_intersection *dup, ref_intersection *tail,
+ _Jv_BytecodeVerifier *verifier)
+ : ref_next (tail)
+ {
+ is_resolved = dup->is_resolved;
+ data = dup->data;
+ alloc_next = verifier->isect_list;
+ verifier->isect_list = this;
+ }
+
+ bool equals (ref_intersection *other, _Jv_BytecodeVerifier *verifier)
+ {
+ if (! is_resolved && ! other->is_resolved
+ && _Jv_equalUtf8Classnames (data.name, other->data.name))
+ return true;
+ if (! is_resolved)
+ resolve (verifier);
+ if (! other->is_resolved)
+ other->resolve (verifier);
+ return data.klass == other->data.klass;
+ }
+
+ // Merge THIS type into OTHER, returning the result. This will
+ // return OTHER if all the classes in THIS already appear in
+ // OTHER.
+ ref_intersection *merge (ref_intersection *other,
+ _Jv_BytecodeVerifier *verifier)
+ {
+ ref_intersection *tail = other;
+ for (ref_intersection *self = this; self != NULL; self = self->ref_next)
+ {
+ bool add = true;
+ for (ref_intersection *iter = other; iter != NULL;
+ iter = iter->ref_next)
+ {
+ if (iter->equals (self, verifier))
+ {
+ add = false;
+ break;
+ }
+ }
+
+ if (add)
+ tail = new ref_intersection (self, tail, verifier);
+ }
+ return tail;
+ }
+
+ void resolve (_Jv_BytecodeVerifier *verifier)
+ {
+ if (is_resolved)
+ return;
+
+ // This is useful if you want to see which classes have to be resolved
+ // while doing the class verification.
+ debug_print("resolving class: %s\n", data.name->chars());
+
+ using namespace java::lang;
+ java::lang::ClassLoader *loader
+ = verifier->current_class->getClassLoaderInternal();
+
+ // Due to special handling in to_array() array classes will always
+ // be of the "L ... ;" kind. The separator char ('.' or '/' may vary
+ // however.
+ if (data.name->limit()[-1] == ';')
+ {
+ data.klass = _Jv_FindClassFromSignature (data.name->chars(), loader);
+ if (data.klass == NULL)
+ throw new java::lang::NoClassDefFoundError(data.name->toString());
+ }
+ else
+ data.klass = Class::forName (_Jv_NewStringUtf8Const (data.name),
+ false, loader);
+ is_resolved = true;
+ }
+
+ // See if an object of type OTHER can be assigned to an object of
+ // type *THIS. This might resolve classes in one chain or the
+ // other.
+ bool compatible (ref_intersection *other,
+ _Jv_BytecodeVerifier *verifier)
+ {
+ ref_intersection *self = this;
+
+ for (; self != NULL; self = self->ref_next)
+ {
+ ref_intersection *other_iter = other;
+
+ for (; other_iter != NULL; other_iter = other_iter->ref_next)
+ {
+ // Avoid resolving if possible.
+ if (! self->is_resolved
+ && ! other_iter->is_resolved
+ && _Jv_equalUtf8Classnames (self->data.name,
+ other_iter->data.name))
+ continue;
+
+ if (! self->is_resolved)
+ self->resolve(verifier);
+
+ // If the LHS of the expression is of type
+ // java.lang.Object, assignment will succeed, no matter
+ // what the type of the RHS is. Using this short-cut we
+ // don't need to resolve the class of the RHS at
+ // verification time.
+ if (self->data.klass == &java::lang::Object::class$)
+ continue;
+
+ if (! other_iter->is_resolved)
+ other_iter->resolve(verifier);
+
+ if (! is_assignable_from_slow (self->data.klass,
+ other_iter->data.klass))
+ return false;
+ }
+ }
+
+ return true;
+ }
+
+ bool isarray ()
+ {
+ // assert (ref_next == NULL);
+ if (is_resolved)
+ return data.klass->isArray ();
+ else
+ return data.name->first() == '[';
+ }
+
+ bool isinterface (_Jv_BytecodeVerifier *verifier)
+ {
+ // assert (ref_next == NULL);
+ if (! is_resolved)
+ resolve (verifier);
+ return data.klass->isInterface ();
+ }
+
+ bool isabstract (_Jv_BytecodeVerifier *verifier)
+ {
+ // assert (ref_next == NULL);
+ if (! is_resolved)
+ resolve (verifier);
+ using namespace java::lang::reflect;
+ return Modifier::isAbstract (data.klass->getModifiers ());
+ }
+
+ jclass getclass (_Jv_BytecodeVerifier *verifier)
+ {
+ if (! is_resolved)
+ resolve (verifier);
+ return data.klass;
+ }
+
+ int count_dimensions ()
+ {
+ int ndims = 0;
+ if (is_resolved)
+ {
+ jclass k = data.klass;
+ while (k->isArray ())
+ {
+ k = k->getComponentType ();
+ ++ndims;
+ }
+ }
+ else
+ {
+ char *p = data.name->chars();
+ while (*p++ == '[')
+ ++ndims;
+ }
+ return ndims;
+ }
+
+ void *operator new (size_t bytes)
+ {
+ return _Jv_Malloc (bytes);
+ }
+
+ void operator delete (void *mem)
+ {
+ _Jv_Free (mem);
+ }
};
// Return the type_val corresponding to a primitive signature
// character. For instance `I' returns `int.class'.
- static type_val get_type_val_for_signature (jchar sig)
+ type_val get_type_val_for_signature (jchar sig)
{
type_val rt;
switch (sig)
}
// Return the type_val corresponding to a primitive class.
- static type_val get_type_val_for_signature (jclass k)
+ type_val get_type_val_for_signature (jclass k)
{
return get_type_val_for_signature ((jchar) k->method_count);
}
// TARGET haven't been prepared.
static bool is_assignable_from_slow (jclass target, jclass source)
{
- // This will terminate when SOURCE==Object.
- while (true)
+ // First, strip arrays.
+ while (target->isArray ())
+ {
+ // If target is array, source must be as well.
+ if (! source->isArray ())
+ return false;
+ target = target->getComponentType ();
+ source = source->getComponentType ();
+ }
+
+ // Quick success.
+ if (target == &java::lang::Object::class$)
+ return true;
+
+ do
{
if (source == target)
return true;
if (target->isPrimitive () || source->isPrimitive ())
return false;
- // _Jv_IsAssignableFrom can handle a target which is an
- // interface even if it hasn't been prepared.
- if ((target->state > JV_STATE_LINKED || target->isInterface ())
- && source->state > JV_STATE_LINKED)
- return _Jv_IsAssignableFrom (target, source);
-
- if (target->isArray ())
- {
- if (! source->isArray ())
- return false;
- target = target->getComponentType ();
- source = source->getComponentType ();
- }
- else if (target->isInterface ())
+ if (target->isInterface ())
{
for (int i = 0; i < source->interface_count; ++i)
{
// We use a recursive call because we also need to
// check superinterfaces.
- if (is_assignable_from_slow (target, source->interfaces[i]))
- return true;
+ if (is_assignable_from_slow (target, source->getInterface (i)))
+ return true;
}
- return false;
}
- else if (target == &java::lang::Object::class$)
- return true;
- else if (source->isInterface ()
- || source == &java::lang::Object::class$)
- return false;
- else
- source = source->getSuperclass ();
+ source = source->getSuperclass ();
}
- }
+ while (source != NULL);
- // This is used to keep track of which `jsr's correspond to a given
- // jsr target.
- struct subr_info
- {
- // PC of the instruction just after the jsr.
- int pc;
- // Link.
- subr_info *next;
- };
+ return false;
+ }
// The `type' class is used to represent a single type in the
// verifier.
struct type
{
- // The type.
+ // The type key.
type_val key;
- // Some associated data.
- union
- {
- // For a resolved reference type, this is a pointer to the class.
- jclass klass;
- // For other reference types, this it the name of the class.
- _Jv_Utf8Const *name;
- } data;
- // This is used when constructing a new object. It is the PC of the
+
+ // For reference types, the representation of the type.
+ ref_intersection *klass;
+
+ // This is used in two situations.
+ //
+ // First, when constructing a new object, it is the PC of the
// `new' instruction which created the object. We use the special
- // value -2 to mean that this is uninitialized, and the special
- // value -1 for the case where the current method is itself the
- // <init> method.
+ // value UNINIT to mean that this is uninitialized. The special
+ // value SELF is used for the case where the current method is
+ // itself the <init> method. the special value EITHER is used
+ // when we may optionally allow either an uninitialized or
+ // initialized reference to match.
+ //
+ // Second, when the key is return_address_type, this holds the PC
+ // of the instruction following the `jsr'.
int pc;
static const int UNINIT = -2;
static const int SELF = -1;
+ static const int EITHER = -3;
// Basic constructor.
type ()
{
key = unsuitable_type;
- data.klass = NULL;
+ klass = NULL;
pc = UNINIT;
}
type (type_val k)
{
key = k;
- data.klass = NULL;
- if (key == reference_type)
- data.klass = &java::lang::Object::class$;
+ // For reference_type, if KLASS==NULL then that means we are
+ // looking for a generic object of any kind, including an
+ // uninitialized reference.
+ klass = NULL;
pc = UNINIT;
}
// Make a new instance given a class.
- type (jclass klass)
+ type (jclass k, _Jv_BytecodeVerifier *verifier)
{
key = reference_type;
- data.klass = klass;
+ klass = new ref_intersection (k, verifier);
pc = UNINIT;
}
// Make a new instance given the name of a class.
- type (_Jv_Utf8Const *n)
+ type (_Jv_Utf8Const *n, _Jv_BytecodeVerifier *verifier)
{
- key = unresolved_reference_type;
- data.name = n;
+ key = reference_type;
+ klass = new ref_intersection (n, verifier);
pc = UNINIT;
}
type (const type &t)
{
key = t.key;
- data = t.data;
+ klass = t.klass;
pc = t.pc;
}
type& operator= (type_val k)
{
key = k;
- data.klass = NULL;
+ klass = NULL;
pc = UNINIT;
return *this;
}
type& operator= (const type& t)
{
key = t.key;
- data = t.data;
+ klass = t.klass;
pc = t.pc;
return *this;
}
return *this;
}
- // If *THIS is an unresolved reference type, resolve it.
- void resolve ()
- {
- if (key != unresolved_reference_type
- && key != uninitialized_unresolved_reference_type)
- return;
-
- // FIXME: class loader
- using namespace java::lang;
- // We might see either kind of name. Sigh.
- if (data.name->data[0] == 'L'
- && data.name->data[data.name->length - 1] == ';')
- data.klass = _Jv_FindClassFromSignature (data.name->data, NULL);
- else
- data.klass = Class::forName (_Jv_NewStringUtf8Const (data.name),
- false, NULL);
- key = (key == unresolved_reference_type
- ? reference_type
- : uninitialized_reference_type);
- }
-
// Mark this type as the uninitialized result of `new'.
- void set_uninitialized (int npc)
+ void set_uninitialized (int npc, _Jv_BytecodeVerifier *verifier)
{
if (key == reference_type)
key = uninitialized_reference_type;
- else if (key == unresolved_reference_type)
- key = uninitialized_unresolved_reference_type;
else
- verify_fail ("internal error in type::uninitialized");
+ verifier->verify_fail ("internal error in type::uninitialized");
pc = npc;
}
// Mark this type as now initialized.
void set_initialized (int npc)
{
- if (npc != UNINIT && pc == npc
- && (key == uninitialized_reference_type
- || key == uninitialized_unresolved_reference_type))
+ if (npc != UNINIT && pc == npc && key == uninitialized_reference_type)
{
- key = (key == uninitialized_reference_type
- ? reference_type
- : unresolved_reference_type);
+ key = reference_type;
pc = UNINIT;
}
}
+ // Mark this type as a particular return address.
+ void set_return_address (int npc)
+ {
+ pc = npc;
+ }
+
+ // Return true if this type and type OTHER are considered
+ // mergeable for the purposes of state merging. This is related
+ // to subroutine handling. For this purpose two types are
+ // considered unmergeable if they are both return-addresses but
+ // have different PCs.
+ bool state_mergeable_p (const type &other) const
+ {
+ return (key != return_address_type
+ || other.key != return_address_type
+ || pc == other.pc);
+ }
// Return true if an object of type K can be assigned to a variable
// of type *THIS. Handle various special cases too. Might modify
// *THIS or K. Note however that this does not perform numeric
// promotion.
- bool compatible (type &k)
+ bool compatible (type &k, _Jv_BytecodeVerifier *verifier)
{
// Any type is compatible with the unsuitable type.
if (key == unsuitable_type)
if (key < reference_type || k.key < reference_type)
return key == k.key;
- // The `null' type is convertible to any reference type.
- // FIXME: is this correct for THIS?
- if (key == null_type || k.key == null_type)
- return true;
+ // The `null' type is convertible to any initialized reference
+ // type.
+ if (key == null_type)
+ return k.key != uninitialized_reference_type;
+ if (k.key == null_type)
+ return key != uninitialized_reference_type;
- // Any reference type is convertible to Object. This is a special
- // case so we don't need to unnecessarily resolve a class.
- if (key == reference_type
- && data.klass == &java::lang::Object::class$)
+ // A special case for a generic reference.
+ if (klass == NULL)
return true;
+ if (k.klass == NULL)
+ verifier->verify_fail ("programmer error in type::compatible");
- // An initialized type and an uninitialized type are not
- // compatible.
- if (isinitialized () != k.isinitialized ())
- return false;
-
- // Two uninitialized objects are compatible if either:
- // * The PCs are identical, or
- // * One PC is UNINIT.
- if (! isinitialized ())
+ // Handle the special 'EITHER' case, which is only used in a
+ // special case of 'putfield'. Note that we only need to handle
+ // this on the LHS of a check.
+ if (! isinitialized () && pc == EITHER)
{
- if (pc != k.pc && pc != UNINIT && k.pc != UNINIT)
+ // If the RHS is uninitialized, it must be an uninitialized
+ // 'this'.
+ if (! k.isinitialized () && k.pc != SELF)
return false;
}
+ else if (isinitialized () != k.isinitialized ())
+ {
+ // An initialized type and an uninitialized type are not
+ // otherwise compatible.
+ return false;
+ }
+ else
+ {
+ // Two uninitialized objects are compatible if either:
+ // * The PCs are identical, or
+ // * One PC is UNINIT.
+ if (! isinitialized ())
+ {
+ if (pc != k.pc && pc != UNINIT && k.pc != UNINIT)
+ return false;
+ }
+ }
- // Two unresolved types are equal if their names are the same.
- if (! isresolved ()
- && ! k.isresolved ()
- && _Jv_equalUtf8Consts (data.name, k.data.name))
- return true;
+ return klass->compatible(k.klass, verifier);
+ }
- // We must resolve both types and check assignability.
- resolve ();
- k.resolve ();
- return is_assignable_from_slow (data.klass, k.data.klass);
+ bool equals (const type &other, _Jv_BytecodeVerifier *vfy)
+ {
+ // Only works for reference types.
+ if ((key != reference_type
+ && key != uninitialized_reference_type)
+ || (other.key != reference_type
+ && other.key != uninitialized_reference_type))
+ return false;
+ // Only for single-valued types.
+ if (klass->ref_next || other.klass->ref_next)
+ return false;
+ return klass->equals (other.klass, vfy);
}
bool isvoid () const
// We treat null_type as not an array. This is ok based on the
// current uses of this method.
if (key == reference_type)
- return data.klass->isArray ();
- else if (key == unresolved_reference_type)
- return data.name->data[0] == '[';
+ return klass->isarray ();
return false;
}
- bool isinterface ()
+ bool isnull () const
+ {
+ return key == null_type;
+ }
+
+ bool isinterface (_Jv_BytecodeVerifier *verifier)
{
- resolve ();
if (key != reference_type)
return false;
- return data.klass->isInterface ();
+ return klass->isinterface (verifier);
}
- bool isabstract ()
+ bool isabstract (_Jv_BytecodeVerifier *verifier)
{
- resolve ();
if (key != reference_type)
return false;
- using namespace java::lang::reflect;
- return Modifier::isAbstract (data.klass->getModifiers ());
+ return klass->isabstract (verifier);
}
// Return the element type of an array.
- type element_type ()
+ type element_type (_Jv_BytecodeVerifier *verifier)
{
- // FIXME: maybe should do string manipulation here.
- resolve ();
if (key != reference_type)
- verify_fail ("programmer error in type::element_type()");
+ verifier->verify_fail ("programmer error in type::element_type()", -1);
- jclass k = data.klass->getComponentType ();
+ jclass k = klass->getclass (verifier)->getComponentType ();
if (k->isPrimitive ())
- return type (get_type_val_for_signature (k));
- return type (k);
+ return type (verifier->get_type_val_for_signature (k));
+ return type (k, verifier);
}
// Return the array type corresponding to an initialized
// reference. We could expand this to work for other kinds of
// types, but currently we don't need to.
- type to_array ()
+ type to_array (_Jv_BytecodeVerifier *verifier)
{
- // Resolving isn't ideal, because it might force us to load
- // another class, but it's easy. FIXME?
- if (key == unresolved_reference_type)
- resolve ();
-
- if (key == reference_type)
- return type (_Jv_GetArrayClass (data.klass,
- data.klass->getClassLoader ()));
+ if (key != reference_type)
+ verifier->verify_fail ("internal error in type::to_array()");
+
+ // In case the class is already resolved we can simply ask the runtime
+ // to give us the array version.
+ // If it is not resolved we prepend "[" to the classname to make the
+ // array usage verification more lazy. In other words: makes new Foo[300]
+ // pass the verifier if Foo.class is missing.
+ if (klass->is_resolved)
+ {
+ jclass k = klass->getclass (verifier);
+
+ return type (_Jv_GetArrayClass (k, k->getClassLoaderInternal()),
+ verifier);
+ }
else
- verify_fail ("internal error in type::to_array()");
+ {
+ int len = klass->data.name->len();
+
+ // If the classname is given in the Lp1/p2/cn; format we only need
+ // to add a leading '['. The same procedure has to be done for
+ // primitive arrays (ie. provided "[I", the result should be "[[I".
+ // If the classname is given as p1.p2.cn we have to embed it into
+ // "[L" and ';'.
+ if (klass->data.name->limit()[-1] == ';' ||
+ _Jv_isPrimitiveOrDerived(klass->data.name))
+ {
+ // Reserves space for leading '[' and trailing '\0' .
+ char arrayName[len + 2];
+
+ arrayName[0] = '[';
+ strcpy(&arrayName[1], klass->data.name->chars());
+
+#ifdef VERIFY_DEBUG
+ // This is only needed when we want to print the string to the
+ // screen while debugging.
+ arrayName[len + 1] = '\0';
+
+ debug_print("len: %d - old: '%s' - new: '%s'\n", len, klass->data.name->chars(), arrayName);
+#endif
+
+ return type (verifier->make_utf8_const( arrayName, len + 1 ),
+ verifier);
+ }
+ else
+ {
+ // Reserves space for leading "[L" and trailing ';' and '\0' .
+ char arrayName[len + 4];
+
+ arrayName[0] = '[';
+ arrayName[1] = 'L';
+ strcpy(&arrayName[2], klass->data.name->chars());
+ arrayName[len + 2] = ';';
+
+#ifdef VERIFY_DEBUG
+ // This is only needed when we want to print the string to the
+ // screen while debugging.
+ arrayName[len + 3] = '\0';
+
+ debug_print("len: %d - old: '%s' - new: '%s'\n", len, klass->data.name->chars(), arrayName);
+#endif
+
+ return type (verifier->make_utf8_const( arrayName, len + 3 ),
+ verifier);
+ }
+ }
+
}
bool isreference () const
bool isinitialized () const
{
- return (key == reference_type
- || key == null_type
- || key == unresolved_reference_type);
+ return key == reference_type || key == null_type;
}
bool isresolved () const
|| key == uninitialized_reference_type);
}
- void verify_dimensions (int ndims)
+ void verify_dimensions (int ndims, _Jv_BytecodeVerifier *verifier)
{
// The way this is written, we don't need to check isarray().
- if (key == reference_type)
- {
- jclass k = data.klass;
- while (k->isArray () && ndims > 0)
- {
- k = k->getComponentType ();
- --ndims;
- }
- }
- else
- {
- // We know KEY == unresolved_reference_type.
- char *p = data.name->data;
- while (*p++ == '[' && ndims-- > 0)
- ;
- }
+ if (key != reference_type)
+ verifier->verify_fail ("internal error in verify_dimensions:"
+ " not a reference type");
- if (ndims > 0)
- verify_fail ("array type has fewer dimensions than required");
+ if (klass->count_dimensions () < ndims)
+ verifier->verify_fail ("array type has fewer dimensions"
+ " than required");
}
- // Merge OLD_TYPE into this. On error throw exception.
- bool merge (type& old_type, bool local_semantics = false)
+ // Merge OLD_TYPE into this. On error throw exception. Return
+ // true if the merge caused a type change.
+ bool merge (type& old_type, bool local_semantics,
+ _Jv_BytecodeVerifier *verifier)
{
bool changed = false;
bool refo = old_type.isreference ();
changed = true;
}
else if (isinitialized () != old_type.isinitialized ())
- verify_fail ("merging initialized and uninitialized types");
+ verifier->verify_fail ("merging initialized and uninitialized types");
else
{
if (! isinitialized ())
else if (old_type.pc == UNINIT)
;
else if (pc != old_type.pc)
- verify_fail ("merging different uninitialized types");
+ verifier->verify_fail ("merging different uninitialized types");
}
- if (! isresolved ()
- && ! old_type.isresolved ()
- && _Jv_equalUtf8Consts (data.name, old_type.data.name))
+ ref_intersection *merged = old_type.klass->merge (klass,
+ verifier);
+ if (merged != klass)
{
- // Types are identical.
- }
- else
- {
- resolve ();
- old_type.resolve ();
-
- jclass k = data.klass;
- jclass oldk = old_type.data.klass;
-
- int arraycount = 0;
- while (k->isArray () && oldk->isArray ())
- {
- ++arraycount;
- k = k->getComponentType ();
- oldk = oldk->getComponentType ();
- }
-
- // This loop will end when we hit Object.
- while (true)
- {
- if (is_assignable_from_slow (k, oldk))
- break;
- k = k->getSuperclass ();
- changed = true;
- }
-
- if (changed)
- {
- while (arraycount > 0)
- {
- // FIXME: Class loader.
- k = _Jv_GetArrayClass (k, NULL);
- --arraycount;
- }
- data.klass = k;
- }
+ klass = merged;
+ changed = true;
}
}
}
{
if (local_semantics)
{
- key = unsuitable_type;
- changed = true;
+ // If we already have an `unsuitable' type, then we
+ // don't need to change again.
+ if (key != unsuitable_type)
+ {
+ key = unsuitable_type;
+ changed = true;
+ }
}
else
- verify_fail ("unmergeable type");
+ verifier->verify_fail ("unmergeable type");
}
return changed;
}
+
+#ifdef VERIFY_DEBUG
+ void print (void) const
+ {
+ char c = '?';
+ switch (key)
+ {
+ case boolean_type: c = 'Z'; break;
+ case byte_type: c = 'B'; break;
+ case char_type: c = 'C'; break;
+ case short_type: c = 'S'; break;
+ case int_type: c = 'I'; break;
+ case long_type: c = 'J'; break;
+ case float_type: c = 'F'; break;
+ case double_type: c = 'D'; break;
+ case void_type: c = 'V'; break;
+ case unsuitable_type: c = '-'; break;
+ case return_address_type: c = 'r'; break;
+ case continuation_type: c = '+'; break;
+ case reference_type: c = 'L'; break;
+ case null_type: c = '@'; break;
+ case uninitialized_reference_type: c = 'U'; break;
+ }
+ debug_print ("%c", c);
+ }
+#endif /* VERIFY_DEBUG */
};
// This class holds all the state information we need for a given
// location.
struct state
{
- // Current top of stack.
+ // The current top of the stack, in terms of slots.
int stacktop;
- // Current stack depth. This is like the top of stack but it
- // includes wide variable information.
+ // The current depth of the stack. This will be larger than
+ // STACKTOP when wide types are on the stack.
int stackdepth;
// The stack.
type *stack;
// The local variables.
type *locals;
- // This is used in subroutines to keep track of which local
- // variables have been accessed.
- bool *local_changed;
- // If not 0, then we are in a subroutine. The value is the PC of
- // the subroutine's entry point. We can use 0 as an exceptional
- // value because PC=0 can never be a subroutine.
- int subroutine;
- // This is used to keep a linked list of all the states which
- // require re-verification. We use the PC to keep track.
- int next;
-
- // INVALID marks a state which is not on the linked list of states
- // requiring reverification.
- static const int INVALID = -1;
- // NO_NEXT marks the state at the end of the reverification list.
- static const int NO_NEXT = -2;
+ // We keep track of the type of `this' specially. This is used to
+ // ensure that an instance initializer invokes another initializer
+ // on `this' before returning. We must keep track of this
+ // specially because otherwise we might be confused by code which
+ // assigns to locals[0] (overwriting `this') and then returns
+ // without really initializing.
+ type this_type;
+
+ // The PC for this state. This is only valid on states which are
+ // permanently attached to a given PC. For an object like
+ // `current_state', which is used transiently, this has no
+ // meaning.
+ int pc;
+ // We keep a linked list of all states requiring reverification.
+ // If this is the special value INVALID_STATE then this state is
+ // not on the list. NULL marks the end of the linked list.
+ state *next;
+
+ // NO_NEXT is the PC value meaning that a new state must be
+ // acquired from the verification list.
+ static const int NO_NEXT = -1;
state ()
+ : this_type ()
{
stack = NULL;
locals = NULL;
- local_changed = NULL;
+ next = INVALID_STATE;
}
state (int max_stack, int max_locals)
+ : this_type ()
{
stacktop = 0;
stackdepth = 0;
for (int i = 0; i < max_stack; ++i)
stack[i] = unsuitable_type;
locals = new type[max_locals];
- local_changed = (bool *) _Jv_Malloc (sizeof (bool) * max_locals);
for (int i = 0; i < max_locals; ++i)
- {
- locals[i] = unsuitable_type;
- local_changed[i] = false;
- }
- next = INVALID;
- subroutine = 0;
+ locals[i] = unsuitable_type;
+ pc = NO_NEXT;
+ next = INVALID_STATE;
}
state (const state *orig, int max_stack, int max_locals)
{
stack = new type[max_stack];
locals = new type[max_locals];
- local_changed = (bool *) _Jv_Malloc (sizeof (bool) * max_locals);
copy (orig, max_stack, max_locals);
- next = INVALID;
+ pc = NO_NEXT;
+ next = INVALID_STATE;
}
~state ()
delete[] stack;
if (locals)
delete[] locals;
- if (local_changed)
- _Jv_Free (local_changed);
}
void *operator new[] (size_t bytes)
{
stacktop = copy->stacktop;
stackdepth = copy->stackdepth;
- subroutine = copy->subroutine;
for (int i = 0; i < max_stack; ++i)
stack[i] = copy->stack[i];
for (int i = 0; i < max_locals; ++i)
- {
- locals[i] = copy->locals[i];
- local_changed[i] = copy->local_changed[i];
- }
- // Don't modify `next'.
+ locals[i] = copy->locals[i];
+
+ this_type = copy->this_type;
+ // Don't modify `next' or `pc'.
}
// Modify this state to reflect entry to an exception handler.
stack[0] = t;
for (int i = stacktop; i < max_stack; ++i)
stack[i] = unsuitable_type;
+ }
+
+ inline int get_pc () const
+ {
+ return pc;
+ }
- // FIXME: subroutine handling?
+ void set_pc (int npc)
+ {
+ pc = npc;
}
- // Merge STATE into this state. Destructively modifies this state.
- // Returns true if the new state was in fact changed. Will throw an
- // exception if the states are not mergeable.
- bool merge (state *state_old, bool ret_semantics,
- int max_locals)
+ // Merge STATE_OLD into this state. Destructively modifies this
+ // state. Returns true if the new state was in fact changed.
+ // Will throw an exception if the states are not mergeable.
+ bool merge (state *state_old, int max_locals,
+ _Jv_BytecodeVerifier *verifier)
{
bool changed = false;
- // Merge subroutine states. *THIS and *STATE_OLD must be in the
- // same subroutine. Also, recursive subroutine calls must be
- // avoided.
- if (subroutine == state_old->subroutine)
- {
- // Nothing.
- }
- else if (subroutine == 0)
- {
- subroutine = state_old->subroutine;
- changed = true;
- }
- else
- verify_fail ("subroutines merged");
+ // Special handling for `this'. If one or the other is
+ // uninitialized, then the merge is uninitialized.
+ if (this_type.isinitialized ())
+ this_type = state_old->this_type;
// Merge stacks.
- if (state_old->stacktop != stacktop)
- verify_fail ("stack sizes differ");
+ if (state_old->stacktop != stacktop) // FIXME stackdepth instead?
+ verifier->verify_fail ("stack sizes differ");
for (int i = 0; i < state_old->stacktop; ++i)
{
- if (stack[i].merge (state_old->stack[i]))
+ if (stack[i].merge (state_old->stack[i], false, verifier))
changed = true;
}
// Merge local variables.
for (int i = 0; i < max_locals; ++i)
{
- if (! ret_semantics || local_changed[i])
- {
- if (locals[i].merge (state_old->locals[i], true))
- {
- changed = true;
- note_variable (i);
- }
- }
-
- // If we're in a subroutine, we must compute the union of
- // all the changed local variables.
- if (state_old->local_changed[i])
- note_variable (i);
+ if (locals[i].merge (state_old->locals[i], true, verifier))
+ changed = true;
}
return changed;
}
- // Throw an exception if there is an uninitialized object on the
- // stack or in a local variable. EXCEPTION_SEMANTICS controls
- // whether we're using backwards-branch or exception-handing
- // semantics.
- void check_no_uninitialized_objects (int max_locals,
- bool exception_semantics = false)
+ // Ensure that `this' has been initialized.
+ void check_this_initialized (_Jv_BytecodeVerifier *verifier)
{
- if (! exception_semantics)
- {
- for (int i = 0; i < stacktop; ++i)
- if (stack[i].isreference () && ! stack[i].isinitialized ())
- verify_fail ("uninitialized object on stack");
- }
-
- for (int i = 0; i < max_locals; ++i)
- if (locals[i].isreference () && ! locals[i].isinitialized ())
- verify_fail ("uninitialized object in local variable");
+ if (this_type.isreference () && ! this_type.isinitialized ())
+ verifier->verify_fail ("`this' is uninitialized");
}
- // Note that a local variable was accessed or modified.
- void note_variable (int index)
+ // Set type of `this'.
+ void set_this_type (const type &k)
{
- if (subroutine > 0)
- local_changed[index] = true;
+ this_type = k;
}
// Mark each `new'd object we know of that was allocated at PC as
stack[i].set_initialized (pc);
for (int i = 0; i < max_locals; ++i)
locals[i].set_initialized (pc);
+ this_type.set_initialized (pc);
}
+
+ // This tests to see whether two states can be considered "merge
+ // compatible". If both states have a return-address in the same
+ // slot, and the return addresses are different, then they are not
+ // compatible and we must not try to merge them.
+ bool state_mergeable_p (state *other, int max_locals,
+ _Jv_BytecodeVerifier *verifier)
+ {
+ // This is tricky: if the stack sizes differ, then not only are
+ // these not mergeable, but in fact we should give an error, as
+ // we've found two execution paths that reach a branch target
+ // with different stack depths. FIXME stackdepth instead?
+ if (stacktop != other->stacktop)
+ verifier->verify_fail ("stack sizes differ");
+
+ for (int i = 0; i < stacktop; ++i)
+ if (! stack[i].state_mergeable_p (other->stack[i]))
+ return false;
+ for (int i = 0; i < max_locals; ++i)
+ if (! locals[i].state_mergeable_p (other->locals[i]))
+ return false;
+ return true;
+ }
+
+ void reverify (_Jv_BytecodeVerifier *verifier)
+ {
+ if (next == INVALID_STATE)
+ {
+ next = verifier->next_verify_state;
+ verifier->next_verify_state = this;
+ }
+ }
+
+#ifdef VERIFY_DEBUG
+ void print (const char *leader, int pc,
+ int max_stack, int max_locals) const
+ {
+ debug_print ("%s [%4d]: [stack] ", leader, pc);
+ int i;
+ for (i = 0; i < stacktop; ++i)
+ stack[i].print ();
+ for (; i < max_stack; ++i)
+ debug_print (".");
+ debug_print (" [local] ");
+ for (i = 0; i < max_locals; ++i)
+ locals[i].print ();
+ debug_print (" | %p\n", this);
+ }
+#else
+ inline void print (const char *, int, int, int) const
+ {
+ }
+#endif /* VERIFY_DEBUG */
};
type pop_raw ()
{
if (current_state->stacktop <= 0)
- verify_fail ("stack empty", start_PC);
+ verify_fail ("stack empty");
type r = current_state->stack[--current_state->stacktop];
current_state->stackdepth -= r.depth ();
if (current_state->stackdepth < 0)
{
type r = pop_raw ();
if (r.iswide ())
- verify_fail ("narrow pop of wide type", start_PC);
+ verify_fail ("narrow pop of wide type");
return r;
}
- type pop64 ()
+ type pop_type (type match)
{
- type r = pop_raw ();
- if (! r.iswide ())
- verify_fail ("wide pop of narrow type", start_PC);
- return r;
+ match.promote ();
+ type t = pop_raw ();
+ if (! match.compatible (t, this))
+ verify_fail ("incompatible type on stack");
+ return t;
}
- type pop_type (type match)
+ // Pop a reference which is guaranteed to be initialized. MATCH
+ // doesn't have to be a reference type; in this case this acts like
+ // pop_type.
+ type pop_init_ref (type match)
{
- match.promote ();
type t = pop_raw ();
- if (! match.compatible (t))
- verify_fail ("incompatible type on stack", start_PC);
+ if (t.isreference () && ! t.isinitialized ())
+ verify_fail ("initialized reference required");
+ else if (! match.compatible (t, this))
+ verify_fail ("incompatible type on stack");
+ return t;
+ }
+
+ // Pop a reference type or a return address.
+ type pop_ref_or_return ()
+ {
+ type t = pop_raw ();
+ if (! t.isreference () && t.key != return_address_type)
+ verify_fail ("expected reference or return address on stack");
return t;
}
if (index > current_method->max_locals - depth)
verify_fail ("invalid local variable");
current_state->locals[index] = t;
- current_state->note_variable (index);
if (depth == 2)
- {
- current_state->locals[index + 1] = continuation_type;
- current_state->note_variable (index + 1);
- }
+ current_state->locals[index + 1] = continuation_type;
if (index > 0 && current_state->locals[index - 1].iswide ())
- {
- current_state->locals[index - 1] = unsuitable_type;
- // There's no need to call note_variable here.
- }
+ current_state->locals[index - 1] = unsuitable_type;
}
type get_variable (int index, type t)
{
int depth = t.depth ();
if (index > current_method->max_locals - depth)
- verify_fail ("invalid local variable", start_PC);
- if (! t.compatible (current_state->locals[index]))
- verify_fail ("incompatible type in local variable", start_PC);
+ verify_fail ("invalid local variable");
+ if (! t.compatible (current_state->locals[index], this))
+ verify_fail ("incompatible type in local variable");
if (depth == 2)
{
type t (continuation_type);
- if (! current_state->locals[index + 1].compatible (t))
- verify_fail ("invalid local variable", start_PC);
+ if (! current_state->locals[index + 1].compatible (t, this))
+ verify_fail ("invalid local variable");
}
- current_state->note_variable (index);
return current_state->locals[index];
}
// compatible with type ELEMENT. Returns the actual element type.
type require_array_type (type array, type element)
{
+ // An odd case. Here we just pretend that everything went ok. If
+ // the requested element type is some kind of reference, return
+ // the null type instead.
+ if (array.isnull ())
+ return element.isreference () ? type (null_type) : element;
+
if (! array.isarray ())
verify_fail ("array required");
- type t = array.element_type ();
- if (! element.compatible (t))
+ type t = array.element_type (this);
+ if (! element.compatible (t, this))
{
// Special case for byte arrays, which must also be boolean
// arrays.
if (element.key == byte_type)
{
type e2 (boolean_type);
- ok = e2.compatible (t);
+ ok = e2.compatible (t, this);
}
if (! ok)
verify_fail ("incompatible array element type");
return npc;
}
- // Merge the indicated state into a new state and schedule a new PC if
- // there is a change. If RET_SEMANTICS is true, then we are merging
- // from a `ret' instruction into the instruction after a `jsr'. This
- // is a special case with its own modified semantics.
- void push_jump_merge (int npc, state *nstate, bool ret_semantics = false)
+ // Add a new state to the state list at NPC.
+ state *add_new_state (int npc, state *old_state)
+ {
+ state *new_state = new state (old_state, current_method->max_stack,
+ current_method->max_locals);
+ debug_print ("== New state in add_new_state\n");
+ new_state->print ("New", npc, current_method->max_stack,
+ current_method->max_locals);
+ linked<state> *nlink
+ = (linked<state> *) _Jv_Malloc (sizeof (linked<state>));
+ nlink->val = new_state;
+ nlink->next = states[npc];
+ states[npc] = nlink;
+ new_state->set_pc (npc);
+ return new_state;
+ }
+
+ // Merge the indicated state into the state at the branch target and
+ // schedule a new PC if there is a change. NPC is the PC of the
+ // branch target, and FROM_STATE is the state at the source of the
+ // branch. This method returns true if the destination state
+ // changed and requires reverification, false otherwise.
+ void merge_into (int npc, state *from_state)
{
- bool changed = true;
- if (states[npc] == NULL)
+ // Iterate over all target states and merge our state into each,
+ // if applicable. FIXME one improvement we could make here is
+ // "state destruction". Merging a new state into an existing one
+ // might cause a return_address_type to be merged to
+ // unsuitable_type. In this case the resulting state may now be
+ // mergeable with other states currently held in parallel at this
+ // location. So in this situation we could pairwise compare and
+ // reduce the number of parallel states.
+ bool applicable = false;
+ for (linked<state> *iter = states[npc]; iter != NULL; iter = iter->next)
{
- // FIXME: what if we reach this code from a `ret'?
-
- states[npc] = new state (nstate, current_method->max_stack,
- current_method->max_locals);
+ state *new_state = iter->val;
+ if (new_state->state_mergeable_p (from_state,
+ current_method->max_locals, this))
+ {
+ applicable = true;
+
+ debug_print ("== Merge states in merge_into\n");
+ from_state->print ("Frm", start_PC, current_method->max_stack,
+ current_method->max_locals);
+ new_state->print (" To", npc, current_method->max_stack,
+ current_method->max_locals);
+ bool changed = new_state->merge (from_state,
+ current_method->max_locals,
+ this);
+ new_state->print ("New", npc, current_method->max_stack,
+ current_method->max_locals);
+
+ if (changed)
+ new_state->reverify (this);
+ }
}
- else
- changed = nstate->merge (states[npc], ret_semantics,
- current_method->max_stack);
- if (changed && states[npc]->next == state::INVALID)
+ if (! applicable)
{
- // The merge changed the state, and the new PC isn't yet on our
- // list of PCs to re-verify.
- states[npc]->next = next_verify_pc;
- next_verify_pc = npc;
+ // Either we don't yet have a state at NPC, or we have a
+ // return-address type that is in conflict with all existing
+ // state. So, we need to create a new entry.
+ state *new_state = add_new_state (npc, from_state);
+ // A new state added in this way must always be reverified.
+ new_state->reverify (this);
}
}
void push_jump (int offset)
{
int npc = compute_jump (offset);
- if (npc < PC)
- current_state->check_no_uninitialized_objects (current_method->max_locals);
- push_jump_merge (npc, current_state);
+ // According to the JVM Spec, we need to check for uninitialized
+ // objects here. However, this does not actually affect type
+ // safety, and the Eclipse java compiler generates code that
+ // violates this constraint.
+ merge_into (npc, current_state);
}
void push_exception_jump (type t, int pc)
{
- current_state->check_no_uninitialized_objects (current_method->max_locals,
- true);
+ // According to the JVM Spec, we need to check for uninitialized
+ // objects here. However, this does not actually affect type
+ // safety, and the Eclipse java compiler generates code that
+ // violates this constraint.
state s (current_state, current_method->max_stack,
current_method->max_locals);
+ if (current_method->max_stack < 1)
+ verify_fail ("stack overflow at exception handler");
s.set_exception (t, current_method->max_stack);
- push_jump_merge (pc, &s);
+ merge_into (pc, &s);
}
- int pop_jump ()
+ state *pop_jump ()
{
- int npc = next_verify_pc;
- if (npc != state::NO_NEXT)
+ state *new_state = next_verify_state;
+ if (new_state == INVALID_STATE)
+ verify_fail ("programmer error in pop_jump");
+ if (new_state != NULL)
{
- next_verify_pc = states[npc]->next;
- states[npc]->next = state::INVALID;
+ next_verify_state = new_state->next;
+ new_state->next = INVALID_STATE;
}
- return npc;
+ return new_state;
}
void invalidate_pc ()
PC = state::NO_NEXT;
}
- void note_branch_target (int pc, bool is_jsr_target = false)
+ void note_branch_target (int pc)
{
- if (pc <= PC && ! (flags[pc] & FLAG_INSN_START))
- verify_fail ("branch not to instruction start");
+ // Don't check `pc <= PC', because we've advanced PC after
+ // fetching the target and we haven't yet checked the next
+ // instruction.
+ if (pc < PC && ! (flags[pc] & FLAG_INSN_START))
+ verify_fail ("branch not to instruction start", start_PC);
flags[pc] |= FLAG_BRANCH_TARGET;
- if (is_jsr_target)
- {
- // Record the jsr which called this instruction.
- subr_info *info = (subr_info *) _Jv_Malloc (sizeof (subr_info));
- info->pc = PC;
- info->next = jsr_ptrs[pc];
- jsr_ptrs[pc] = info;
- flags[pc] |= FLAG_JSR_TARGET;
- }
}
void skip_padding ()
verify_fail ("found nonzero padding byte");
}
- // Return the subroutine to which the instruction at PC belongs.
- int get_subroutine (int pc)
- {
- if (states[pc] == NULL)
- return 0;
- return states[pc]->subroutine;
- }
-
// Do the work for a `ret' instruction. INDEX is the index into the
// local variables.
void handle_ret_insn (int index)
{
- get_variable (index, return_address_type);
-
- int csub = current_state->subroutine;
- if (csub == 0)
- verify_fail ("no subroutine");
-
- for (subr_info *subr = jsr_ptrs[csub]; subr != NULL; subr = subr->next)
- {
- // Temporarily modify the current state so it looks like we're
- // in the enclosing context.
- current_state->subroutine = get_subroutine (subr->pc);
- if (subr->pc < PC)
- current_state->check_no_uninitialized_objects (current_method->max_locals);
- push_jump_merge (subr->pc, current_state, true);
- }
-
- current_state->subroutine = csub;
+ type ret_addr = get_variable (index, return_address_type);
+ // It would be nice if we could do this. However, the JVM Spec
+ // doesn't say that this is what happens. It is implied that
+ // reusing a return address is invalid, but there's no actual
+ // prohibition against it.
+ // set_variable (index, unsuitable_type);
+
+ int npc = ret_addr.get_pc ();
+ // We might be returning to a `jsr' that is at the end of the
+ // bytecode. This is ok if we never return from the called
+ // subroutine, but if we see this here it is an error.
+ if (npc >= current_method->code_length)
+ verify_fail ("fell off end");
+
+ // According to the JVM Spec, we need to check for uninitialized
+ // objects here. However, this does not actually affect type
+ // safety, and the Eclipse java compiler generates code that
+ // violates this constraint.
+ merge_into (npc, current_state);
invalidate_pc ();
}
- // We're in the subroutine SUB, calling a subroutine at DEST. Make
- // sure this subroutine isn't already on the stack.
- void check_nonrecursive_call (int sub, int dest)
- {
- if (sub == 0)
- return;
- if (sub == dest)
- verify_fail ("recursive subroutine call");
- for (subr_info *info = jsr_ptrs[sub]; info != NULL; info = info->next)
- check_nonrecursive_call (get_subroutine (info->pc), dest);
- }
-
void handle_jsr_insn (int offset)
{
int npc = compute_jump (offset);
- if (npc < PC)
- current_state->check_no_uninitialized_objects (current_method->max_locals);
- check_nonrecursive_call (current_state->subroutine, npc);
-
- // Temporarily modify the current state so that it looks like we are
- // in the subroutine.
- push_type (return_address_type);
- int save = current_state->subroutine;
- current_state->subroutine = npc;
-
- // Merge into the subroutine.
- push_jump_merge (npc, current_state);
+ // According to the JVM Spec, we need to check for uninitialized
+ // objects here. However, this does not actually affect type
+ // safety, and the Eclipse java compiler generates code that
+ // violates this constraint.
- // Undo our modifications.
- current_state->subroutine = save;
- pop_type (return_address_type);
+ // Modify our state as appropriate for entry into a subroutine.
+ type ret_addr (return_address_type);
+ ret_addr.set_return_address (PC);
+ push_type (ret_addr);
+ merge_into (npc, current_state);
+ invalidate_pc ();
}
jclass construct_primitive_array_type (type_val prim)
case long_type:
k = JvPrimClass (long);
break;
+
+ // These aren't used here but we call them out to avoid
+ // warnings.
+ case void_type:
+ case unsuitable_type:
+ case return_address_type:
+ case continuation_type:
+ case reference_type:
+ case null_type:
+ case uninitialized_reference_type:
default:
verify_fail ("unknown type in construct_primitive_array_type");
}
void branch_prepass ()
{
flags = (char *) _Jv_Malloc (current_method->code_length);
- jsr_ptrs = (subr_info **) _Jv_Malloc (sizeof (subr_info *)
- * current_method->code_length);
for (int i = 0; i < current_method->code_length; ++i)
- {
- flags[i] = 0;
- jsr_ptrs[i] = NULL;
- }
-
- bool last_was_jsr = false;
+ flags[i] = 0;
PC = 0;
while (PC < current_method->code_length)
{
+ // Set `start_PC' early so that error checking can have the
+ // correct value.
+ start_PC = PC;
flags[PC] |= FLAG_INSN_START;
- // If the previous instruction was a jsr, then the next
- // instruction is a branch target -- the branch being the
- // corresponding `ret'.
- if (last_was_jsr)
- note_branch_target (PC);
- last_was_jsr = false;
-
- start_PC = PC;
java_opcode opcode = (java_opcode) bytecode[PC++];
switch (opcode)
{
break;
case op_jsr:
- last_was_jsr = true;
- // Fall through.
case op_ifeq:
case op_ifne:
case op_iflt:
case op_ifnull:
case op_ifnonnull:
case op_goto:
- note_branch_target (compute_jump (get_short ()), last_was_jsr);
+ note_branch_target (compute_jump (get_short ()));
break;
case op_tableswitch:
break;
case op_jsr_w:
- last_was_jsr = true;
- // Fall through.
case op_goto_w:
- note_branch_target (compute_jump (get_int ()), last_was_jsr);
- break;
-
+ note_branch_target (compute_jump (get_int ()));
+ break;
+
+ // These are unused here, but we call them out explicitly
+ // so that -Wswitch-enum doesn't complain.
+ case op_putfield_1:
+ case op_putfield_2:
+ case op_putfield_4:
+ case op_putfield_8:
+ case op_putfield_a:
+ case op_putstatic_1:
+ case op_putstatic_2:
+ case op_putstatic_4:
+ case op_putstatic_8:
+ case op_putstatic_a:
+ case op_getfield_1:
+ case op_getfield_2s:
+ case op_getfield_2u:
+ case op_getfield_4:
+ case op_getfield_8:
+ case op_getfield_a:
+ case op_getstatic_1:
+ case op_getstatic_2s:
+ case op_getstatic_2u:
+ case op_getstatic_4:
+ case op_getstatic_8:
+ case op_getstatic_a:
+ case op_breakpoint:
default:
verify_fail ("unrecognized instruction in branch_prepass",
start_PC);
// Verify exception handlers.
for (int i = 0; i < current_method->exc_count; ++i)
{
- if (! (flags[exception[i].handler_pc] & FLAG_INSN_START))
+ if (! (flags[exception[i].handler_pc.i] & FLAG_INSN_START))
verify_fail ("exception handler not at instruction start",
- exception[i].handler_pc);
- if (exception[i].start_pc > exception[i].end_pc)
- verify_fail ("exception range inverted");
- if (! (flags[exception[i].start_pc] & FLAG_INSN_START))
+ exception[i].handler_pc.i);
+ if (! (flags[exception[i].start_pc.i] & FLAG_INSN_START))
verify_fail ("exception start not at instruction start",
- exception[i].start_pc);
- else if (! (flags[exception[i].end_pc] & FLAG_INSN_START))
+ exception[i].start_pc.i);
+ if (exception[i].end_pc.i != current_method->code_length
+ && ! (flags[exception[i].end_pc.i] & FLAG_INSN_START))
verify_fail ("exception end not at instruction start",
- exception[i].end_pc);
+ exception[i].end_pc.i);
- flags[exception[i].handler_pc] |= FLAG_BRANCH_TARGET;
+ flags[exception[i].handler_pc.i] |= FLAG_BRANCH_TARGET;
}
}
check_pool_index (index);
_Jv_Constants *pool = ¤t_class->constants;
if (pool->tags[index] == JV_CONSTANT_ResolvedClass)
- return type (pool->data[index].clazz);
+ return type (pool->data[index].clazz, this);
else if (pool->tags[index] == JV_CONSTANT_Class)
- return type (pool->data[index].utf8);
+ return type (pool->data[index].utf8, this);
verify_fail ("expected class constant", start_PC);
}
{
check_pool_index (index);
_Jv_Constants *pool = ¤t_class->constants;
- if (pool->tags[index] == JV_CONSTANT_ResolvedString
- || pool->tags[index] == JV_CONSTANT_String)
- return type (&java::lang::String::class$);
- else if (pool->tags[index] == JV_CONSTANT_Integer)
+ int tag = pool->tags[index];
+ if (tag == JV_CONSTANT_ResolvedString || tag == JV_CONSTANT_String)
+ return type (&java::lang::String::class$, this);
+ else if (tag == JV_CONSTANT_Integer)
return type (int_type);
- else if (pool->tags[index] == JV_CONSTANT_Float)
+ else if (tag == JV_CONSTANT_Float)
return type (float_type);
+ else if (current_method->is_15
+ && (tag == JV_CONSTANT_ResolvedClass || tag == JV_CONSTANT_Class))
+ return type (&java::lang::Class::class$, this);
verify_fail ("String, int, or float constant expected", start_PC);
}
}
// Return field's type, compute class' type if requested.
- type check_field_constant (int index, type *class_type = NULL)
+ // If PUTFIELD is true, use the special 'putfield' semantics.
+ type check_field_constant (int index, type *class_type = NULL,
+ bool putfield = false)
{
_Jv_Utf8Const *name, *field_type;
type ct = handle_field_or_method (index,
&name, &field_type);
if (class_type)
*class_type = ct;
- if (field_type->data[0] == '[' || field_type->data[0] == 'L')
- return type (field_type);
- return get_type_val_for_signature (field_type->data[0]);
+ type result;
+ if (field_type->first() == '[' || field_type->first() == 'L')
+ result = type (field_type, this);
+ else
+ result = get_type_val_for_signature (field_type->first());
+
+ // We have an obscure special case here: we can use `putfield' on
+ // a field declared in this class, even if `this' has not yet been
+ // initialized.
+ if (putfield
+ && ! current_state->this_type.isinitialized ()
+ && current_state->this_type.pc == type::SELF
+ && current_state->this_type.equals (ct, this)
+ // We don't look at the signature, figuring that if it is
+ // wrong we will fail during linking. FIXME?
+ && _Jv_Linker::has_field_p (current_class, name))
+ // Note that we don't actually know whether we're going to match
+ // against 'this' or some other object of the same type. So,
+ // here we set things up so that it doesn't matter. This relies
+ // on knowing what our caller is up to.
+ class_type->set_uninitialized (type::EITHER, this);
+
+ return result;
}
type check_method_constant (int index, bool is_interface,
while (*p != ';')
++p;
++p;
- // FIXME! This will get collected!
- _Jv_Utf8Const *name = _Jv_makeUtf8Const (start, p - start);
- return type (name);
+ _Jv_Utf8Const *name = make_utf8_const (start, p - start);
+ return type (name, this);
}
// Casting to jchar here is ok since we are looking at an ASCII
jclass k = construct_primitive_array_type (rt);
while (--arraycount > 0)
k = _Jv_GetArrayClass (k, NULL);
- return type (k);
+ return type (k, this);
}
void compute_argument_types (_Jv_Utf8Const *signature,
type *types)
{
- char *p = signature->data;
+ char *p = signature->chars();
+
// Skip `('.
++p;
type compute_return_type (_Jv_Utf8Const *signature)
{
- char *p = signature->data;
+ char *p = signature->chars();
while (*p != ')')
++p;
++p;
void check_return_type (type onstack)
{
type rt = compute_return_type (current_method->self->signature);
- if (! rt.compatible (onstack))
- verify_fail ("incompatible return type", start_PC);
+ if (! rt.compatible (onstack, this))
+ verify_fail ("incompatible return type");
+ }
+
+ // Initialize the stack for the new method. Returns true if this
+ // method is an instance initializer.
+ bool initialize_stack ()
+ {
+ int var = 0;
+ bool is_init = _Jv_equalUtf8Consts (current_method->self->name,
+ gcj::init_name);
+ bool is_clinit = _Jv_equalUtf8Consts (current_method->self->name,
+ gcj::clinit_name);
+
+ using namespace java::lang::reflect;
+ if (! Modifier::isStatic (current_method->self->accflags))
+ {
+ type kurr (current_class, this);
+ if (is_init)
+ {
+ kurr.set_uninitialized (type::SELF, this);
+ is_init = true;
+ }
+ else if (is_clinit)
+ verify_fail ("<clinit> method must be static");
+ set_variable (0, kurr);
+ current_state->set_this_type (kurr);
+ ++var;
+ }
+ else
+ {
+ if (is_init)
+ verify_fail ("<init> method must be non-static");
+ }
+
+ // We have to handle wide arguments specially here.
+ int arg_count = _Jv_count_arguments (current_method->self->signature);
+ type arg_types[arg_count];
+ compute_argument_types (current_method->self->signature, arg_types);
+ for (int i = 0; i < arg_count; ++i)
+ {
+ set_variable (var, arg_types[i]);
+ ++var;
+ if (arg_types[i].iswide ())
+ ++var;
+ }
+
+ return is_init;
}
void verify_instructions_0 ()
PC = 0;
start_PC = 0;
- {
- int var = 0;
+ // True if we are verifying an instance initializer.
+ bool this_is_init = initialize_stack ();
- using namespace java::lang::reflect;
- if (! Modifier::isStatic (current_method->self->accflags))
- {
- type kurr (current_class);
- if (_Jv_equalUtf8Consts (current_method->self->name, gcj::init_name))
- kurr.set_uninitialized (type::SELF);
- set_variable (0, kurr);
- ++var;
- }
-
- // We have to handle wide arguments specially here.
- int arg_count = _Jv_count_arguments (current_method->self->signature);
- type arg_types[arg_count];
- compute_argument_types (current_method->self->signature, arg_types);
- for (int i = 0; i < arg_count; ++i)
- {
- set_variable (var, arg_types[i]);
- ++var;
- if (arg_types[i].iswide ())
- ++var;
- }
- }
-
- states = (state **) _Jv_Malloc (sizeof (state *)
- * current_method->code_length);
+ states = (linked<state> **) _Jv_Malloc (sizeof (linked<state> *)
+ * current_method->code_length);
for (int i = 0; i < current_method->code_length; ++i)
states[i] = NULL;
- next_verify_pc = state::NO_NEXT;
+ next_verify_state = NULL;
while (true)
{
// If the PC was invalidated, get a new one from the work list.
if (PC == state::NO_NEXT)
{
- PC = pop_jump ();
- if (PC == state::INVALID)
- verify_fail ("saw state::INVALID", start_PC);
- if (PC == state::NO_NEXT)
+ state *new_state = pop_jump ();
+ // If it is null, we're done.
+ if (new_state == NULL)
break;
+
+ PC = new_state->get_pc ();
+ debug_print ("== State pop from pending list\n");
// Set up the current state.
- *current_state = *states[PC];
+ current_state->copy (new_state, current_method->max_stack,
+ current_method->max_locals);
}
-
- // Control can't fall off the end of the bytecode.
- if (PC >= current_method->code_length)
- verify_fail ("fell off end");
-
- if (states[PC] != NULL)
+ else
{
- // We've already visited this instruction. So merge the
- // states together. If this yields no change then we don't
- // have to re-verify.
- if (! current_state->merge (states[PC], false,
- current_method->max_stack))
+ // We only have to do this checking in the situation where
+ // control flow falls through from the previous
+ // instruction. Otherwise merging is done at the time we
+ // push the branch. Note that we'll catch the
+ // off-the-end problem just below.
+ if (PC < current_method->code_length && states[PC] != NULL)
{
+ // We've already visited this instruction. So merge
+ // the states together. It is simplest, but not most
+ // efficient, to just always invalidate the PC here.
+ merge_into (PC, current_state);
invalidate_pc ();
continue;
}
- // Save a copy of it for later.
- states[PC]->copy (current_state, current_method->max_stack,
- current_method->max_locals);
- }
- else if ((flags[PC] & FLAG_BRANCH_TARGET))
- {
- // We only have to keep saved state at branch targets.
- states[PC] = new state (current_state, current_method->max_stack,
- current_method->max_locals);
}
+ // Control can't fall off the end of the bytecode. We need to
+ // check this in both cases, not just the fall-through case,
+ // because we don't check to see whether a `jsr' appears at
+ // the end of the bytecode until we process a `ret'.
+ if (PC >= current_method->code_length)
+ verify_fail ("fell off end");
+
+ // We only have to keep saved state at branch targets. If
+ // we're at a branch target and the state here hasn't been set
+ // yet, we set it now. You might notice that `ret' targets
+ // won't necessarily have FLAG_BRANCH_TARGET set. This
+ // doesn't matter, since those states will be filled in by
+ // merge_into.
+ if (states[PC] == NULL && (flags[PC] & FLAG_BRANCH_TARGET))
+ add_new_state (PC, current_state);
+
+ // Set this before handling exceptions so that debug output is
+ // sane.
+ start_PC = PC;
+
// Update states for all active exception handlers. Ordinarily
// there are not many exception handlers. So we simply run
// through them all.
for (int i = 0; i < current_method->exc_count; ++i)
{
- if (PC >= exception[i].start_pc && PC < exception[i].end_pc)
+ if (PC >= exception[i].start_pc.i && PC < exception[i].end_pc.i)
{
- type handler = reference_type;
- if (exception[i].handler_type != 0)
- handler = check_class_constant (exception[i].handler_type);
- push_exception_jump (handler, exception[i].handler_pc);
+ type handler (&java::lang::Throwable::class$, this);
+ if (exception[i].handler_type.i != 0)
+ handler = check_class_constant (exception[i].handler_type.i);
+ push_exception_jump (handler, exception[i].handler_pc.i);
}
}
- start_PC = PC;
+ current_state->print (" ", PC, current_method->max_stack,
+ current_method->max_locals);
java_opcode opcode = (java_opcode) bytecode[PC++];
switch (opcode)
{
break;
case op_iaload:
pop_type (int_type);
- push_type (require_array_type (pop_type (reference_type),
+ push_type (require_array_type (pop_init_ref (reference_type),
int_type));
break;
case op_laload:
pop_type (int_type);
- push_type (require_array_type (pop_type (reference_type),
+ push_type (require_array_type (pop_init_ref (reference_type),
long_type));
break;
case op_faload:
pop_type (int_type);
- push_type (require_array_type (pop_type (reference_type),
+ push_type (require_array_type (pop_init_ref (reference_type),
float_type));
break;
case op_daload:
pop_type (int_type);
- push_type (require_array_type (pop_type (reference_type),
+ push_type (require_array_type (pop_init_ref (reference_type),
double_type));
break;
case op_aaload:
pop_type (int_type);
- push_type (require_array_type (pop_type (reference_type),
+ push_type (require_array_type (pop_init_ref (reference_type),
reference_type));
break;
case op_baload:
pop_type (int_type);
- require_array_type (pop_type (reference_type), byte_type);
+ require_array_type (pop_init_ref (reference_type), byte_type);
push_type (int_type);
break;
case op_caload:
pop_type (int_type);
- require_array_type (pop_type (reference_type), char_type);
+ require_array_type (pop_init_ref (reference_type), char_type);
push_type (int_type);
break;
case op_saload:
pop_type (int_type);
- require_array_type (pop_type (reference_type), short_type);
+ require_array_type (pop_init_ref (reference_type), short_type);
push_type (int_type);
break;
case op_istore:
set_variable (get_byte (), pop_type (double_type));
break;
case op_astore:
- set_variable (get_byte (), pop_type (reference_type));
+ set_variable (get_byte (), pop_ref_or_return ());
break;
case op_istore_0:
case op_istore_1:
case op_astore_1:
case op_astore_2:
case op_astore_3:
- set_variable (opcode - op_astore_0, pop_type (reference_type));
+ set_variable (opcode - op_astore_0, pop_ref_or_return ());
break;
case op_iastore:
pop_type (int_type);
pop_type (int_type);
- require_array_type (pop_type (reference_type), int_type);
+ require_array_type (pop_init_ref (reference_type), int_type);
break;
case op_lastore:
pop_type (long_type);
pop_type (int_type);
- require_array_type (pop_type (reference_type), long_type);
+ require_array_type (pop_init_ref (reference_type), long_type);
break;
case op_fastore:
pop_type (float_type);
pop_type (int_type);
- require_array_type (pop_type (reference_type), float_type);
+ require_array_type (pop_init_ref (reference_type), float_type);
break;
case op_dastore:
pop_type (double_type);
pop_type (int_type);
- require_array_type (pop_type (reference_type), double_type);
+ require_array_type (pop_init_ref (reference_type), double_type);
break;
case op_aastore:
pop_type (reference_type);
pop_type (int_type);
- require_array_type (pop_type (reference_type), reference_type);
+ require_array_type (pop_init_ref (reference_type), reference_type);
break;
case op_bastore:
pop_type (int_type);
pop_type (int_type);
- require_array_type (pop_type (reference_type), byte_type);
+ require_array_type (pop_init_ref (reference_type), byte_type);
break;
case op_castore:
pop_type (int_type);
pop_type (int_type);
- require_array_type (pop_type (reference_type), char_type);
+ require_array_type (pop_init_ref (reference_type), char_type);
break;
case op_sastore:
pop_type (int_type);
pop_type (int_type);
- require_array_type (pop_type (reference_type), short_type);
+ require_array_type (pop_init_ref (reference_type), short_type);
break;
case op_pop:
pop32 ();
break;
case op_pop2:
- pop64 ();
+ {
+ type t = pop_raw ();
+ if (! t.iswide ())
+ pop32 ();
+ }
break;
case op_dup:
{
push_type (t);
push_type (t2);
}
+ else
+ push_type (t);
push_type (t);
}
break;
break;
case op_dup2_x2:
{
- // FIXME
type t1 = pop_raw ();
if (t1.iswide ())
{
invalidate_pc ();
break;
case op_areturn:
- check_return_type (pop_type (reference_type));
+ check_return_type (pop_init_ref (reference_type));
invalidate_pc ();
break;
case op_return:
+ // We only need to check this when the return type is
+ // void, because all instance initializers return void.
+ if (this_is_init)
+ current_state->check_this_initialized (this);
check_return_type (void_type);
invalidate_pc ();
break;
case op_putfield:
{
type klass;
- type field = check_field_constant (get_ushort (), &klass);
+ type field = check_field_constant (get_ushort (), &klass, true);
pop_type (field);
pop_type (klass);
}
opcode == op_invokeinterface,
&method_name,
&method_signature);
- int arg_count = _Jv_count_arguments (method_signature);
+ // NARGS is only used when we're processing
+ // invokeinterface. It is simplest for us to compute it
+ // here and then verify it later.
+ int nargs = 0;
if (opcode == op_invokeinterface)
{
- int nargs = get_byte ();
- if (nargs == 0)
- verify_fail ("too few arguments to invokeinterface",
- start_PC);
+ nargs = get_byte ();
if (get_byte () != 0)
- verify_fail ("invokeinterface dummy byte is wrong",
- start_PC);
- if (nargs - 1 != arg_count)
- verify_fail ("wrong argument count for invokeinterface",
- start_PC);
+ verify_fail ("invokeinterface dummy byte is wrong");
}
bool is_init = false;
{
is_init = true;
if (opcode != op_invokespecial)
- verify_fail ("can't invoke <init>", start_PC);
+ verify_fail ("can't invoke <init>");
}
- else if (method_name->data[0] == '<')
- verify_fail ("can't invoke method starting with `<'",
- start_PC);
+ else if (method_name->first() == '<')
+ verify_fail ("can't invoke method starting with `<'");
// Pop arguments and check types.
+ int arg_count = _Jv_count_arguments (method_signature);
type arg_types[arg_count];
compute_argument_types (method_signature, arg_types);
for (int i = arg_count - 1; i >= 0; --i)
- pop_type (arg_types[i]);
+ {
+ // This is only used for verifying the byte for
+ // invokeinterface.
+ nargs -= arg_types[i].depth ();
+ pop_init_ref (arg_types[i]);
+ }
+
+ if (opcode == op_invokeinterface
+ && nargs != 1)
+ verify_fail ("wrong argument count for invokeinterface");
if (opcode != op_invokestatic)
{
if (is_init)
{
// In this case the PC doesn't matter.
- t.set_uninitialized (type::UNINIT);
+ t.set_uninitialized (type::UNINIT, this);
+ // FIXME: check to make sure that the <init>
+ // call is to the right class.
+ // It must either be super or an exact class
+ // match.
}
- t = pop_type (t);
+ type raw = pop_raw ();
+ if (! t.compatible (raw, this))
+ verify_fail ("incompatible type on stack");
+
if (is_init)
- current_state->set_initialized (t.get_pc (),
+ current_state->set_initialized (raw.get_pc (),
current_method->max_locals);
}
case op_new:
{
type t = check_class_constant (get_ushort ());
- if (t.isarray () || t.isinterface () || t.isabstract ())
- verify_fail ("type is array, interface, or abstract",
- start_PC);
- t.set_uninitialized (start_PC);
+ if (t.isarray ())
+ verify_fail ("type is array");
+ t.set_uninitialized (start_PC, this);
push_type (t);
}
break;
if (atype < boolean_type || atype > long_type)
verify_fail ("type not primitive", start_PC);
pop_type (int_type);
- push_type (construct_primitive_array_type (type_val (atype)));
+ type t (construct_primitive_array_type (type_val (atype)), this);
+ push_type (t);
}
break;
case op_anewarray:
pop_type (int_type);
- push_type (check_class_constant (get_ushort ()).to_array ());
+ push_type (check_class_constant (get_ushort ()).to_array (this));
break;
case op_arraylength:
{
- type t = pop_type (reference_type);
- if (! t.isarray ())
- verify_fail ("array type expected", start_PC);
+ type t = pop_init_ref (reference_type);
+ if (! t.isarray () && ! t.isnull ())
+ verify_fail ("array type expected");
push_type (int_type);
}
break;
case op_athrow:
- pop_type (type (&java::lang::Throwable::class$));
+ pop_type (type (&java::lang::Throwable::class$, this));
invalidate_pc ();
break;
case op_checkcast:
- pop_type (reference_type);
+ pop_init_ref (reference_type);
push_type (check_class_constant (get_ushort ()));
break;
case op_instanceof:
- pop_type (reference_type);
+ pop_init_ref (reference_type);
check_class_constant (get_ushort ());
push_type (int_type);
break;
case op_monitorenter:
- pop_type (reference_type);
+ pop_init_ref (reference_type);
break;
case op_monitorexit:
- pop_type (reference_type);
+ pop_init_ref (reference_type);
break;
case op_wide:
{
set_variable (get_ushort (), pop_type (double_type));
break;
case op_astore:
- set_variable (get_ushort (), pop_type (reference_type));
+ set_variable (get_ushort (), pop_init_ref (reference_type));
break;
case op_ret:
handle_ret_insn (get_short ());
int dim = get_byte ();
if (dim < 1)
verify_fail ("too few dimensions to multianewarray", start_PC);
- atype.verify_dimensions (dim);
+ atype.verify_dimensions (dim, this);
for (int i = 0; i < dim; ++i)
pop_type (int_type);
push_type (atype);
handle_jsr_insn (get_int ());
break;
+ // These are unused here, but we call them out explicitly
+ // so that -Wswitch-enum doesn't complain.
+ case op_putfield_1:
+ case op_putfield_2:
+ case op_putfield_4:
+ case op_putfield_8:
+ case op_putfield_a:
+ case op_putstatic_1:
+ case op_putstatic_2:
+ case op_putstatic_4:
+ case op_putstatic_8:
+ case op_putstatic_a:
+ case op_getfield_1:
+ case op_getfield_2s:
+ case op_getfield_2u:
+ case op_getfield_4:
+ case op_getfield_8:
+ case op_getfield_a:
+ case op_getstatic_1:
+ case op_getstatic_2s:
+ case op_getstatic_2u:
+ case op_getstatic_4:
+ case op_getstatic_8:
+ case op_getstatic_a:
+ case op_breakpoint:
default:
// Unrecognized opcode.
verify_fail ("unrecognized instruction in verify_instructions_0",
_Jv_BytecodeVerifier (_Jv_InterpMethod *m)
{
+ // We just print the text as utf-8. This is just for debugging
+ // anyway.
+ debug_print ("--------------------------------\n");
+ debug_print ("-- Verifying method `%s'\n", m->self->name->chars());
+
current_method = m;
bytecode = m->bytecode ();
exception = m->exceptions ();
states = NULL;
flags = NULL;
- jsr_ptrs = NULL;
+ utf8_list = NULL;
+ isect_list = NULL;
}
~_Jv_BytecodeVerifier ()
{
- if (states)
- _Jv_Free (states);
if (flags)
_Jv_Free (flags);
- if (jsr_ptrs)
- _Jv_Free (jsr_ptrs);
+
+ while (utf8_list != NULL)
+ {
+ linked<_Jv_Utf8Const> *n = utf8_list->next;
+ _Jv_Free (utf8_list);
+ utf8_list = n;
+ }
+
+ while (isect_list != NULL)
+ {
+ ref_intersection *next = isect_list->alloc_next;
+ delete isect_list;
+ isect_list = next;
+ }
+
+ if (states)
+ {
+ for (int i = 0; i < current_method->code_length; ++i)
+ {
+ linked<state> *iter = states[i];
+ while (iter != NULL)
+ {
+ linked<state> *next = iter->next;
+ delete iter->val;
+ _Jv_Free (iter);
+ iter = next;
+ }
+ }
+ _Jv_Free (states);
+ }
}
};
v.verify_instructions ();
}
-// FIXME: add more info, like PC, when required.
-static void
-verify_fail (char *s, jint pc)
-{
- using namespace java::lang;
- StringBuffer *buf = new StringBuffer ();
-
- buf->append (JvNewStringLatin1 ("verification failed"));
- if (pc != -1)
- {
- buf->append (JvNewStringLatin1 (" at PC "));
- buf->append (pc);
- }
- buf->append (JvNewStringLatin1 (": "));
- buf->append (JvNewStringLatin1 (s));
- throw new java::lang::VerifyError (buf->toString ());
-}
-
#endif /* INTERPRETER */
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