[GCC 4.8] Initial check-in of GCC 4.8.0

Change-Id: I0719d8a6d0f69b367a6ab6f10eb75622dbf12771

1 files changed, 3236 insertions, 0 deletions

diff --git a/gcc-4.8/libjava/verify.cc b/gcc-4.8/libjava/verify.cc
new file mode 100644
index 000000000..b002c1c0a
--- /dev/null
+++ b/gcc-4.8/libjava/verify.cc
@@ -0,0 +1,3236 @@
+// verify.cc - verify bytecode
+
+/* Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006  Free Software Foundation
+
+   This file is part of libgcj.
+
+This software is copyrighted work licensed under the terms of the
+Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
+details.  */
+
+// 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/VerifyError.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 */
+
+
+// This is used to mark states which are not scheduled for
+// verification.
+#define INVALID_STATE ((state *) -1)
+
+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;
+
+  struct state;
+  struct type;
+  struct linked_utf8;
+  struct ref_intersection;
+
+  template<typename T>
+  struct linked
+  {
+    T *val;
+    linked<T> *next;
+  };
+
+  // The current PC.
+  int PC;
+  // The PC corresponding to the start of the current instruction.
+  int start_PC;
+
+  // The current state of the stack, locals, etc.
+  state *current_state;
+
+  // 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 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.  This is an array indexed by PC.
+  char *flags;
+
+  // The bytecode itself.
+  unsigned char *bytecode;
+  // The exceptions.
+  _Jv_InterpException *exception;
+
+  // Defining class.
+  jclass current_class;
+  // 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.
+  enum type_val
+  {
+    void_type,
+
+    // The values for primitive types are chosen to correspond to values
+    // specified to newarray.
+    boolean_type = 4,
+    char_type = 5,
+    float_type = 6,
+    double_type = 7,
+    byte_type = 8,
+    short_type = 9,
+    int_type = 10,
+    long_type = 11,
+
+    // Used when overwriting second word of a double or long in the
+    // local variables.  Also used after merging local variable states
+    // 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,
+    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'.
+  type_val get_type_val_for_signature (jchar sig)
+  {
+    type_val rt;
+    switch (sig)
+      {
+      case 'Z':
+	rt = boolean_type;
+	break;
+      case 'B':
+	rt = byte_type;
+	break;
+      case 'C':
+	rt = char_type;
+	break;
+      case 'S':
+	rt = short_type;
+	break;
+      case 'I':
+	rt = int_type;
+	break;
+      case 'J':
+	rt = long_type;
+	break;
+      case 'F':
+	rt = float_type;
+	break;
+      case 'D':
+	rt = double_type;
+	break;
+      case 'V':
+	rt = void_type;
+	break;
+      default:
+	verify_fail ("invalid signature");
+      }
+    return rt;
+  }
+
+  // Return the type_val corresponding to a primitive class.
+  type_val get_type_val_for_signature (jclass k)
+  {
+    return get_type_val_for_signature ((jchar) k->method_count);
+  }
+
+  // This is like _Jv_IsAssignableFrom, but it works even if SOURCE or
+  // TARGET haven't been prepared.
+  static bool is_assignable_from_slow (jclass target, jclass source)
+  {
+    // 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;
+
+	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->getInterface (i)))
+		  return true;
+	      }
+	  }
+	source = source->getSuperclass ();
+      }
+    while (source != NULL);
+
+    return false;
+  }
+
+  // The `type' class is used to represent a single type in the
+  // verifier.
+  struct type
+  {
+    // The type key.
+    type_val key;
+
+    // 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 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;
+      klass = NULL;
+      pc = UNINIT;
+    }
+
+    // Make a new instance given the type tag.  We assume a generic
+    // `reference_type' means Object.
+    type (type_val k)
+    {
+      key = k;
+      // 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 k, _Jv_BytecodeVerifier *verifier)
+    {
+      key = reference_type;
+      klass = new ref_intersection (k, verifier);
+      pc = UNINIT;
+    }
+
+    // Make a new instance given the name of a class.
+    type (_Jv_Utf8Const *n, _Jv_BytecodeVerifier *verifier)
+    {
+      key = reference_type;
+      klass = new ref_intersection (n, verifier);
+      pc = UNINIT;
+    }
+
+    // Copy constructor.
+    type (const type &t)
+    {
+      key = t.key;
+      klass = t.klass;
+      pc = t.pc;
+    }
+
+    // These operators are required because libgcj can't link in
+    // -lstdc++.
+    void *operator new[] (size_t bytes)
+    {
+      return _Jv_Malloc (bytes);
+    }
+
+    void operator delete[] (void *mem)
+    {
+      _Jv_Free (mem);
+    }
+
+    type& operator= (type_val k)
+    {
+      key = k;
+      klass = NULL;
+      pc = UNINIT;
+      return *this;
+    }
+
+    type& operator= (const type& t)
+    {
+      key = t.key;
+      klass = t.klass;
+      pc = t.pc;
+      return *this;
+    }
+
+    // Promote a numeric type.
+    type &promote ()
+    {
+      if (key == boolean_type || key == char_type
+	  || key == byte_type || key == short_type)
+	key = int_type;
+      return *this;
+    }
+
+    // Mark this type as the uninitialized result of `new'.
+    void set_uninitialized (int npc, _Jv_BytecodeVerifier *verifier)
+    {
+      if (key == reference_type)
+	key = uninitialized_reference_type;
+      else
+	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 = 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, _Jv_BytecodeVerifier *verifier)
+    {
+      // Any type is compatible with the unsuitable type.
+      if (key == unsuitable_type)
+	return true;
+
+      if (key < reference_type || k.key < reference_type)
+	return key == k.key;
+
+      // 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;
+
+      // A special case for a generic reference.
+      if (klass == NULL)
+	return true;
+      if (k.klass == NULL)
+	verifier->verify_fail ("programmer error in type::compatible");
+
+      // 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 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;
+	    }
+	}
+
+      return klass->compatible(k.klass, verifier);
+    }
+
+    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
+    {
+      return key == void_type;
+    }
+
+    bool iswide () const
+    {
+      return key == long_type || key == double_type;
+    }
+
+    // Return number of stack or local variable slots taken by this
+    // type.
+    int depth () const
+    {
+      return iswide () ? 2 : 1;
+    }
+
+    bool isarray () 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 klass->isarray ();
+      return false;
+    }
+
+    bool isnull () const
+    {
+      return key == null_type;
+    }
+
+    bool isinterface (_Jv_BytecodeVerifier *verifier)
+    {
+      if (key != reference_type)
+	return false;
+      return klass->isinterface (verifier);
+    }
+
+    bool isabstract (_Jv_BytecodeVerifier *verifier)
+    {
+      if (key != reference_type)
+	return false;
+      return klass->isabstract (verifier);
+    }
+
+    // Return the element type of an array.
+    type element_type (_Jv_BytecodeVerifier *verifier)
+    {
+      if (key != reference_type)
+	verifier->verify_fail ("programmer error in type::element_type()", -1);
+
+      jclass k = klass->getclass (verifier)->getComponentType ();
+      if (k->isPrimitive ())
+	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 (_Jv_BytecodeVerifier *verifier)
+    {
+      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
+        {
+          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
+    {
+      return key >= reference_type;
+    }
+
+    int get_pc () const
+    {
+      return pc;
+    }
+
+    bool isinitialized () const
+    {
+      return key == reference_type || key == null_type;
+    }
+
+    bool isresolved () const
+    {
+      return (key == reference_type
+	      || key == null_type
+	      || key == uninitialized_reference_type);
+    }
+
+    void verify_dimensions (int ndims, _Jv_BytecodeVerifier *verifier)
+    {
+      // The way this is written, we don't need to check isarray().
+      if (key != reference_type)
+	verifier->verify_fail ("internal error in verify_dimensions:"
+			       " not a reference type");
+
+      if (klass->count_dimensions () < ndims)
+	verifier->verify_fail ("array type has fewer dimensions"
+			       " than required");
+    }
+
+    // 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 ();
+      bool refn = isreference ();
+      if (refo && refn)
+	{
+	  if (old_type.key == null_type)
+	    ;
+	  else if (key == null_type)
+	    {
+	      *this = old_type;
+	      changed = true;
+	    }
+	  else if (isinitialized () != old_type.isinitialized ())
+	    verifier->verify_fail ("merging initialized and uninitialized types");
+	  else
+	    {
+	      if (! isinitialized ())
+		{
+		  if (pc == UNINIT)
+		    pc = old_type.pc;
+		  else if (old_type.pc == UNINIT)
+		    ;
+		  else if (pc != old_type.pc)
+		    verifier->verify_fail ("merging different uninitialized types");
+		}
+
+	      ref_intersection *merged = old_type.klass->merge (klass,
+								verifier);
+	      if (merged != klass)
+		{
+		  klass = merged;
+		  changed = true;
+		}
+	    }
+	}
+      else if (refo || refn || key != old_type.key)
+	{
+	  if (local_semantics)
+	    {
+	      // 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
+	    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
+  {
+    // 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 stack.
+    type *stack;
+    // The local variables.
+    type *locals;
+    // 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;
+      next = INVALID_STATE;
+    }
+
+    state (int max_stack, int max_locals)
+      : this_type ()
+    {
+      stacktop = 0;
+      stackdepth = 0;
+      stack = new type[max_stack];
+      for (int i = 0; i < max_stack; ++i)
+	stack[i] = unsuitable_type;
+      locals = new type[max_locals];
+      for (int i = 0; i < max_locals; ++i)
+	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];
+      copy (orig, max_stack, max_locals);
+      pc = NO_NEXT;
+      next = INVALID_STATE;
+    }
+
+    ~state ()
+    {
+      if (stack)
+	delete[] stack;
+      if (locals)
+	delete[] locals;
+    }
+
+    void *operator new[] (size_t bytes)
+    {
+      return _Jv_Malloc (bytes);
+    }
+
+    void operator delete[] (void *mem)
+    {
+      _Jv_Free (mem);
+    }
+
+    void *operator new (size_t bytes)
+    {
+      return _Jv_Malloc (bytes);
+    }
+
+    void operator delete (void *mem)
+    {
+      _Jv_Free (mem);
+    }
+
+    void copy (const state *copy, int max_stack, int max_locals)
+    {
+      stacktop = copy->stacktop;
+      stackdepth = copy->stackdepth;
+      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];
+
+      this_type = copy->this_type;
+      // Don't modify `next' or `pc'.
+    }
+
+    // Modify this state to reflect entry to an exception handler.
+    void set_exception (type t, int max_stack)
+    {
+      stackdepth = 1;
+      stacktop = 1;
+      stack[0] = t;
+      for (int i = stacktop; i < max_stack; ++i)
+	stack[i] = unsuitable_type;
+    }
+
+    inline int get_pc () const
+    {
+      return pc;
+    }
+
+    void set_pc (int npc)
+    {
+      pc = npc;
+    }
+
+    // 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;
+
+      // 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)  // 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], false, verifier))
+	    changed = true;
+	}
+
+      // Merge local variables.
+      for (int i = 0; i < max_locals; ++i)
+	{
+	  if (locals[i].merge (state_old->locals[i], true, verifier))
+	    changed = true;
+	}
+
+      return changed;
+    }
+
+    // Ensure that `this' has been initialized.
+    void check_this_initialized (_Jv_BytecodeVerifier *verifier)
+    {
+      if (this_type.isreference () && ! this_type.isinitialized ())
+	verifier->verify_fail ("`this' is uninitialized");
+    }
+
+    // Set type of `this'.
+    void set_this_type (const type &k)
+    {
+      this_type = k;
+    }
+
+    // Mark each `new'd object we know of that was allocated at PC as
+    // initialized.
+    void set_initialized (int pc, int max_locals)
+    {
+      for (int i = 0; i < stacktop; ++i)
+	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");
+    type r = current_state->stack[--current_state->stacktop];
+    current_state->stackdepth -= r.depth ();
+    if (current_state->stackdepth < 0)
+      verify_fail ("stack empty", start_PC);
+    return r;
+  }
+
+  type pop32 ()
+  {
+    type r = pop_raw ();
+    if (r.iswide ())
+      verify_fail ("narrow pop of wide type");
+    return r;
+  }
+
+  type pop_type (type match)
+  {
+    match.promote ();
+    type t = pop_raw ();
+    if (! match.compatible (t, this))
+      verify_fail ("incompatible type on stack");
+    return t;
+  }
+
+  // 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)
+  {
+    type t = pop_raw ();
+    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;
+  }
+
+  void push_type (type t)
+  {
+    // If T is a numeric type like short, promote it to int.
+    t.promote ();
+
+    int depth = t.depth ();
+    if (current_state->stackdepth + depth > current_method->max_stack)
+      verify_fail ("stack overflow");
+    current_state->stack[current_state->stacktop++] = t;
+    current_state->stackdepth += depth;
+  }
+
+  void set_variable (int index, type t)
+  {
+    // If T is a numeric type like short, promote it to int.
+    t.promote ();
+
+    int depth = t.depth ();
+    if (index > current_method->max_locals - depth)
+      verify_fail ("invalid local variable");
+    current_state->locals[index] = t;
+
+    if (depth == 2)
+      current_state->locals[index + 1] = continuation_type;
+    if (index > 0 && current_state->locals[index - 1].iswide ())
+      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");
+    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, this))
+	  verify_fail ("invalid local variable");
+      }
+    return current_state->locals[index];
+  }
+
+  // Make sure ARRAY is an array type and that its elements are
+  // 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 (this);
+    if (! element.compatible (t, this))
+      {
+	// Special case for byte arrays, which must also be boolean
+	// arrays.
+	bool ok = true;
+	if (element.key == byte_type)
+	  {
+	    type e2 (boolean_type);
+	    ok = e2.compatible (t, this);
+	  }
+	if (! ok)
+	  verify_fail ("incompatible array element type");
+      }
+
+    // Return T and not ELEMENT, because T might be specialized.
+    return t;
+  }
+
+  jint get_byte ()
+  {
+    if (PC >= current_method->code_length)
+      verify_fail ("premature end of bytecode");
+    return (jint) bytecode[PC++] & 0xff;
+  }
+
+  jint get_ushort ()
+  {
+    jint b1 = get_byte ();
+    jint b2 = get_byte ();
+    return (jint) ((b1 << 8) | b2) & 0xffff;
+  }
+
+  jint get_short ()
+  {
+    jint b1 = get_byte ();
+    jint b2 = get_byte ();
+    jshort s = (b1 << 8) | b2;
+    return (jint) s;
+  }
+
+  jint get_int ()
+  {
+    jint b1 = get_byte ();
+    jint b2 = get_byte ();
+    jint b3 = get_byte ();
+    jint b4 = get_byte ();
+    return (b1 << 24) | (b2 << 16) | (b3 << 8) | b4;
+  }
+
+  int compute_jump (int offset)
+  {
+    int npc = start_PC + offset;
+    if (npc < 0 || npc >= current_method->code_length)
+      verify_fail ("branch out of range", start_PC);
+    return npc;
+  }
+
+  // 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)
+  {
+    // 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)
+      {
+	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);
+	  }
+      }
+
+    if (! applicable)
+      {
+	// 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);
+    // 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)
+  {
+    // 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);
+    merge_into (pc, &s);
+  }
+
+  state *pop_jump ()
+  {
+    state *new_state = next_verify_state;
+    if (new_state == INVALID_STATE)
+      verify_fail ("programmer error in pop_jump");
+    if (new_state != NULL)
+      {
+	next_verify_state = new_state->next;
+	new_state->next = INVALID_STATE;
+      }
+    return new_state;
+  }
+
+  void invalidate_pc ()
+  {
+    PC = state::NO_NEXT;
+  }
+
+  void note_branch_target (int pc)
+  {
+    // 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;
+  }
+
+  void skip_padding ()
+  {
+    while ((PC % 4) > 0)
+      if (get_byte () != 0)
+	verify_fail ("found nonzero padding byte");
+  }
+
+  // Do the work for a `ret' instruction.  INDEX is the index into the
+  // local variables.
+  void handle_ret_insn (int index)
+  {
+    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 ();
+  }
+
+  void handle_jsr_insn (int offset)
+  {
+    int npc = compute_jump (offset);
+
+    // 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.
+
+    // 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)
+  {
+    jclass k = NULL;
+    switch (prim)
+      {
+      case boolean_type:
+	k = JvPrimClass (boolean);
+	break;
+      case char_type:
+	k = JvPrimClass (char);
+	break;
+      case float_type:
+	k = JvPrimClass (float);
+	break;
+      case double_type:
+	k = JvPrimClass (double);
+	break;
+      case byte_type:
+	k = JvPrimClass (byte);
+	break;
+      case short_type:
+	k = JvPrimClass (short);
+	break;
+      case int_type:
+	k = JvPrimClass (int);
+	break;
+      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");
+      }
+    k = _Jv_GetArrayClass (k, NULL);
+    return k;
+  }
+
+  // This pass computes the location of branch targets and also
+  // instruction starts.
+  void branch_prepass ()
+  {
+    flags = (char *) _Jv_Malloc (current_method->code_length);
+
+    for (int i = 0; i < current_method->code_length; ++i)
+      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;
+
+	java_opcode opcode = (java_opcode) bytecode[PC++];
+	switch (opcode)
+	  {
+	  case op_nop:
+	  case op_aconst_null:
+	  case op_iconst_m1:
+	  case op_iconst_0:
+	  case op_iconst_1:
+	  case op_iconst_2:
+	  case op_iconst_3:
+	  case op_iconst_4:
+	  case op_iconst_5:
+	  case op_lconst_0:
+	  case op_lconst_1:
+	  case op_fconst_0:
+	  case op_fconst_1:
+	  case op_fconst_2:
+	  case op_dconst_0:
+	  case op_dconst_1:
+	  case op_iload_0:
+	  case op_iload_1:
+	  case op_iload_2:
+	  case op_iload_3:
+	  case op_lload_0:
+	  case op_lload_1:
+	  case op_lload_2:
+	  case op_lload_3:
+	  case op_fload_0:
+	  case op_fload_1:
+	  case op_fload_2:
+	  case op_fload_3:
+	  case op_dload_0:
+	  case op_dload_1:
+	  case op_dload_2:
+	  case op_dload_3:
+	  case op_aload_0:
+	  case op_aload_1:
+	  case op_aload_2:
+	  case op_aload_3:
+	  case op_iaload:
+	  case op_laload:
+	  case op_faload:
+	  case op_daload:
+	  case op_aaload:
+	  case op_baload:
+	  case op_caload:
+	  case op_saload:
+	  case op_istore_0:
+	  case op_istore_1:
+	  case op_istore_2:
+	  case op_istore_3:
+	  case op_lstore_0:
+	  case op_lstore_1:
+	  case op_lstore_2:
+	  case op_lstore_3:
+	  case op_fstore_0:
+	  case op_fstore_1:
+	  case op_fstore_2:
+	  case op_fstore_3:
+	  case op_dstore_0:
+	  case op_dstore_1:
+	  case op_dstore_2:
+	  case op_dstore_3:
+	  case op_astore_0:
+	  case op_astore_1:
+	  case op_astore_2:
+	  case op_astore_3:
+	  case op_iastore:
+	  case op_lastore:
+	  case op_fastore:
+	  case op_dastore:
+	  case op_aastore:
+	  case op_bastore:
+	  case op_castore:
+	  case op_sastore:
+	  case op_pop:
+	  case op_pop2:
+	  case op_dup:
+	  case op_dup_x1:
+	  case op_dup_x2:
+	  case op_dup2:
+	  case op_dup2_x1:
+	  case op_dup2_x2:
+	  case op_swap:
+	  case op_iadd:
+	  case op_isub:
+	  case op_imul:
+	  case op_idiv:
+	  case op_irem:
+	  case op_ishl:
+	  case op_ishr:
+	  case op_iushr:
+	  case op_iand:
+	  case op_ior:
+	  case op_ixor:
+	  case op_ladd:
+	  case op_lsub:
+	  case op_lmul:
+	  case op_ldiv:
+	  case op_lrem:
+	  case op_lshl:
+	  case op_lshr:
+	  case op_lushr:
+	  case op_land:
+	  case op_lor:
+	  case op_lxor:
+	  case op_fadd:
+	  case op_fsub:
+	  case op_fmul:
+	  case op_fdiv:
+	  case op_frem:
+	  case op_dadd:
+	  case op_dsub:
+	  case op_dmul:
+	  case op_ddiv:
+	  case op_drem:
+	  case op_ineg:
+	  case op_i2b:
+	  case op_i2c:
+	  case op_i2s:
+	  case op_lneg:
+	  case op_fneg:
+	  case op_dneg:
+	  case op_i2l:
+	  case op_i2f:
+	  case op_i2d:
+	  case op_l2i:
+	  case op_l2f:
+	  case op_l2d:
+	  case op_f2i:
+	  case op_f2l:
+	  case op_f2d:
+	  case op_d2i:
+	  case op_d2l:
+	  case op_d2f:
+	  case op_lcmp:
+	  case op_fcmpl:
+	  case op_fcmpg:
+	  case op_dcmpl:
+	  case op_dcmpg:
+	  case op_monitorenter:
+	  case op_monitorexit:
+	  case op_ireturn:
+	  case op_lreturn:
+	  case op_freturn:
+	  case op_dreturn:
+	  case op_areturn:
+	  case op_return:
+	  case op_athrow:
+	  case op_arraylength:
+	    break;
+
+	  case op_bipush:
+	  case op_ldc:
+	  case op_iload:
+	  case op_lload:
+	  case op_fload:
+	  case op_dload:
+	  case op_aload:
+	  case op_istore:
+	  case op_lstore:
+	  case op_fstore:
+	  case op_dstore:
+	  case op_astore:
+	  case op_ret:
+	  case op_newarray:
+	    get_byte ();
+	    break;
+
+	  case op_iinc:
+	  case op_sipush:
+	  case op_ldc_w:
+	  case op_ldc2_w:
+	  case op_getstatic:
+	  case op_getfield:
+	  case op_putfield:
+	  case op_putstatic:
+	  case op_new:
+	  case op_anewarray:
+	  case op_instanceof:
+	  case op_checkcast:
+	  case op_invokespecial:
+	  case op_invokestatic:
+	  case op_invokevirtual:
+	    get_short ();
+	    break;
+
+	  case op_multianewarray:
+	    get_short ();
+	    get_byte ();
+	    break;
+
+	  case op_jsr:
+	  case op_ifeq:
+	  case op_ifne:
+	  case op_iflt:
+	  case op_ifge:
+	  case op_ifgt:
+	  case op_ifle:
+	  case op_if_icmpeq:
+	  case op_if_icmpne:
+	  case op_if_icmplt:
+	  case op_if_icmpge:
+	  case op_if_icmpgt:
+	  case op_if_icmple:
+	  case op_if_acmpeq:
+	  case op_if_acmpne:
+	  case op_ifnull:
+	  case op_ifnonnull:
+	  case op_goto:
+	    note_branch_target (compute_jump (get_short ()));
+	    break;
+
+	  case op_tableswitch:
+	    {
+	      skip_padding ();
+	      note_branch_target (compute_jump (get_int ()));
+	      jint low = get_int ();
+	      jint hi = get_int ();
+	      if (low > hi)
+		verify_fail ("invalid tableswitch", start_PC);
+	      for (int i = low; i <= hi; ++i)
+		note_branch_target (compute_jump (get_int ()));
+	    }
+	    break;
+
+	  case op_lookupswitch:
+	    {
+	      skip_padding ();
+	      note_branch_target (compute_jump (get_int ()));
+	      int npairs = get_int ();
+	      if (npairs < 0)
+		verify_fail ("too few pairs in lookupswitch", start_PC);
+	      while (npairs-- > 0)
+		{
+		  get_int ();
+		  note_branch_target (compute_jump (get_int ()));
+		}
+	    }
+	    break;
+
+	  case op_invokeinterface:
+	    get_short ();
+	    get_byte ();
+	    get_byte ();
+	    break;
+
+	  case op_wide:
+	    {
+	      opcode = (java_opcode) get_byte ();
+	      get_short ();
+	      if (opcode == op_iinc)
+		get_short ();
+	    }
+	    break;
+
+	  case op_jsr_w:
+	  case op_goto_w:
+	    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);
+	  }
+
+	// See if any previous branch tried to branch to the middle of
+	// this instruction.
+	for (int pc = start_PC + 1; pc < PC; ++pc)
+	  {
+	    if ((flags[pc] & FLAG_BRANCH_TARGET))
+	      verify_fail ("branch to middle of instruction", pc);
+	  }
+      }
+
+    // Verify exception handlers.
+    for (int i = 0; i < current_method->exc_count; ++i)
+      {
+	if (! (flags[exception[i].handler_pc.i] & FLAG_INSN_START))
+	  verify_fail ("exception handler not at instruction 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.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.i);
+
+	flags[exception[i].handler_pc.i] |= FLAG_BRANCH_TARGET;
+      }
+  }
+
+  void check_pool_index (int index)
+  {
+    if (index < 0 || index >= current_class->constants.size)
+      verify_fail ("constant pool index out of range", start_PC);
+  }
+
+  type check_class_constant (int index)
+  {
+    check_pool_index (index);
+    _Jv_Constants *pool = &current_class->constants;
+    if (pool->tags[index] == JV_CONSTANT_ResolvedClass)
+      return type (pool->data[index].clazz, this);
+    else if (pool->tags[index] == JV_CONSTANT_Class)
+      return type (pool->data[index].utf8, this);
+    verify_fail ("expected class constant", start_PC);
+  }
+
+  type check_constant (int index)
+  {
+    check_pool_index (index);
+    _Jv_Constants *pool = &current_class->constants;
+    int tag = pool->tags[index];
+    if (tag == JV_CONSTANT_ResolvedString || tag == JV_CONSTANT_String)
+      return type (&java::lang::String::class$, this);
+    else if (tag == JV_CONSTANT_Integer)
+      return type (int_type);
+    else if (tag == JV_CONSTANT_Float)
+      return type (float_type);
+    else if (current_method->is_15
+	     && (tag == JV_CONSTANT_ResolvedClass || tag == JV_CONSTANT_Class))
+      return type (&java::lang::Class::class$, this);
+    verify_fail ("String, int, or float constant expected", start_PC);
+  }
+
+  type check_wide_constant (int index)
+  {
+    check_pool_index (index);
+    _Jv_Constants *pool = &current_class->constants;
+    if (pool->tags[index] == JV_CONSTANT_Long)
+      return type (long_type);
+    else if (pool->tags[index] == JV_CONSTANT_Double)
+      return type (double_type);
+    verify_fail ("long or double constant expected", start_PC);
+  }
+
+  // Helper for both field and method.  These are laid out the same in
+  // the constant pool.
+  type handle_field_or_method (int index, int expected,
+			       _Jv_Utf8Const **name,
+			       _Jv_Utf8Const **fmtype)
+  {
+    check_pool_index (index);
+    _Jv_Constants *pool = &current_class->constants;
+    if (pool->tags[index] != expected)
+      verify_fail ("didn't see expected constant", start_PC);
+    // Once we know we have a Fieldref or Methodref we assume that it
+    // is correctly laid out in the constant pool.  I think the code
+    // in defineclass.cc guarantees this.
+    _Jv_ushort class_index, name_and_type_index;
+    _Jv_loadIndexes (&pool->data[index],
+		     class_index,
+		     name_and_type_index);
+    _Jv_ushort name_index, desc_index;
+    _Jv_loadIndexes (&pool->data[name_and_type_index],
+		     name_index, desc_index);
+
+    *name = pool->data[name_index].utf8;
+    *fmtype = pool->data[desc_index].utf8;
+
+    return check_class_constant (class_index);
+  }
+
+  // Return field's type, compute class' type if requested.
+  // 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,
+				      JV_CONSTANT_Fieldref,
+				      &name, &field_type);
+    if (class_type)
+      *class_type = ct;
+    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,
+			      _Jv_Utf8Const **method_name,
+			      _Jv_Utf8Const **method_signature)
+  {
+    return handle_field_or_method (index,
+				   (is_interface
+				    ? JV_CONSTANT_InterfaceMethodref
+				    : JV_CONSTANT_Methodref),
+				   method_name, method_signature);
+  }
+
+  type get_one_type (char *&p)
+  {
+    char *start = p;
+
+    int arraycount = 0;
+    while (*p == '[')
+      {
+	++arraycount;
+	++p;
+      }
+
+    char v = *p++;
+
+    if (v == 'L')
+      {
+	while (*p != ';')
+	  ++p;
+	++p;
+	_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
+    // character.
+    type_val rt = get_type_val_for_signature (jchar (v));
+
+    if (arraycount == 0)
+      {
+	// Callers of this function eventually push their arguments on
+	// the stack.  So, promote them here.
+	return type (rt).promote ();
+      }
+
+    jclass k = construct_primitive_array_type (rt);
+    while (--arraycount > 0)
+      k = _Jv_GetArrayClass (k, NULL);
+    return type (k, this);
+  }
+
+  void compute_argument_types (_Jv_Utf8Const *signature,
+			       type *types)
+  {
+    char *p = signature->chars();
+
+    // Skip `('.
+    ++p;
+
+    int i = 0;
+    while (*p != ')')
+      types[i++] = get_one_type (p);
+  }
+
+  type compute_return_type (_Jv_Utf8Const *signature)
+  {
+    char *p = signature->chars();
+    while (*p != ')')
+      ++p;
+    ++p;
+    return get_one_type (p);
+  }
+
+  void check_return_type (type onstack)
+  {
+    type rt = compute_return_type (current_method->self->signature);
+    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 ()
+  {
+    current_state = new state (current_method->max_stack,
+			       current_method->max_locals);
+
+    PC = 0;
+    start_PC = 0;
+
+    // True if we are verifying an instance initializer.
+    bool this_is_init = initialize_stack ();
+
+    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_state = NULL;
+
+    while (true)
+      {
+	// If the PC was invalidated, get a new one from the work list.
+	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->copy (new_state, current_method->max_stack,
+				 current_method->max_locals);
+	  }
+	else
+	  {
+	    // 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;
+	      }
+	  }
+
+	// 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.i && PC < exception[i].end_pc.i)
+	      {
+		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);
+	      }
+	  }
+
+	current_state->print ("   ", PC, current_method->max_stack,
+			      current_method->max_locals);
+	java_opcode opcode = (java_opcode) bytecode[PC++];
+	switch (opcode)
+	  {
+	  case op_nop:
+	    break;
+
+	  case op_aconst_null:
+	    push_type (null_type);
+	    break;
+
+	  case op_iconst_m1:
+	  case op_iconst_0:
+	  case op_iconst_1:
+	  case op_iconst_2:
+	  case op_iconst_3:
+	  case op_iconst_4:
+	  case op_iconst_5:
+	    push_type (int_type);
+	    break;
+
+	  case op_lconst_0:
+	  case op_lconst_1:
+	    push_type (long_type);
+	    break;
+
+	  case op_fconst_0:
+	  case op_fconst_1:
+	  case op_fconst_2:
+	    push_type (float_type);
+	    break;
+
+	  case op_dconst_0:
+	  case op_dconst_1:
+	    push_type (double_type);
+	    break;
+
+	  case op_bipush:
+	    get_byte ();
+	    push_type (int_type);
+	    break;
+
+	  case op_sipush:
+	    get_short ();
+	    push_type (int_type);
+	    break;
+
+	  case op_ldc:
+	    push_type (check_constant (get_byte ()));
+	    break;
+	  case op_ldc_w:
+	    push_type (check_constant (get_ushort ()));
+	    break;
+	  case op_ldc2_w:
+	    push_type (check_wide_constant (get_ushort ()));
+	    break;
+
+	  case op_iload:
+	    push_type (get_variable (get_byte (), int_type));
+	    break;
+	  case op_lload:
+	    push_type (get_variable (get_byte (), long_type));
+	    break;
+	  case op_fload:
+	    push_type (get_variable (get_byte (), float_type));
+	    break;
+	  case op_dload:
+	    push_type (get_variable (get_byte (), double_type));
+	    break;
+	  case op_aload:
+	    push_type (get_variable (get_byte (), reference_type));
+	    break;
+
+	  case op_iload_0:
+	  case op_iload_1:
+	  case op_iload_2:
+	  case op_iload_3:
+	    push_type (get_variable (opcode - op_iload_0, int_type));
+	    break;
+	  case op_lload_0:
+	  case op_lload_1:
+	  case op_lload_2:
+	  case op_lload_3:
+	    push_type (get_variable (opcode - op_lload_0, long_type));
+	    break;
+	  case op_fload_0:
+	  case op_fload_1:
+	  case op_fload_2:
+	  case op_fload_3:
+	    push_type (get_variable (opcode - op_fload_0, float_type));
+	    break;
+	  case op_dload_0:
+	  case op_dload_1:
+	  case op_dload_2:
+	  case op_dload_3:
+	    push_type (get_variable (opcode - op_dload_0, double_type));
+	    break;
+	  case op_aload_0:
+	  case op_aload_1:
+	  case op_aload_2:
+	  case op_aload_3:
+	    push_type (get_variable (opcode - op_aload_0, reference_type));
+	    break;
+	  case op_iaload:
+	    pop_type (int_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_init_ref (reference_type),
+					   long_type));
+	    break;
+	  case op_faload:
+	    pop_type (int_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_init_ref (reference_type),
+					   double_type));
+	    break;
+	  case op_aaload:
+	    pop_type (int_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_init_ref (reference_type), byte_type);
+	    push_type (int_type);
+	    break;
+	  case op_caload:
+	    pop_type (int_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_init_ref (reference_type), short_type);
+	    push_type (int_type);
+	    break;
+	  case op_istore:
+	    set_variable (get_byte (), pop_type (int_type));
+	    break;
+	  case op_lstore:
+	    set_variable (get_byte (), pop_type (long_type));
+	    break;
+	  case op_fstore:
+	    set_variable (get_byte (), pop_type (float_type));
+	    break;
+	  case op_dstore:
+	    set_variable (get_byte (), pop_type (double_type));
+	    break;
+	  case op_astore:
+	    set_variable (get_byte (), pop_ref_or_return ());
+	    break;
+	  case op_istore_0:
+	  case op_istore_1:
+	  case op_istore_2:
+	  case op_istore_3:
+	    set_variable (opcode - op_istore_0, pop_type (int_type));
+	    break;
+	  case op_lstore_0:
+	  case op_lstore_1:
+	  case op_lstore_2:
+	  case op_lstore_3:
+	    set_variable (opcode - op_lstore_0, pop_type (long_type));
+	    break;
+	  case op_fstore_0:
+	  case op_fstore_1:
+	  case op_fstore_2:
+	  case op_fstore_3:
+	    set_variable (opcode - op_fstore_0, pop_type (float_type));
+	    break;
+	  case op_dstore_0:
+	  case op_dstore_1:
+	  case op_dstore_2:
+	  case op_dstore_3:
+	    set_variable (opcode - op_dstore_0, pop_type (double_type));
+	    break;
+	  case op_astore_0:
+	  case op_astore_1:
+	  case op_astore_2:
+	  case op_astore_3:
+	    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_init_ref (reference_type), int_type);
+	    break;
+	  case op_lastore:
+	    pop_type (long_type);
+	    pop_type (int_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_init_ref (reference_type), float_type);
+	    break;
+	  case op_dastore:
+	    pop_type (double_type);
+	    pop_type (int_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_init_ref (reference_type), reference_type);
+	    break;
+	  case op_bastore:
+	    pop_type (int_type);
+	    pop_type (int_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_init_ref (reference_type), char_type);
+	    break;
+	  case op_sastore:
+	    pop_type (int_type);
+	    pop_type (int_type);
+	    require_array_type (pop_init_ref (reference_type), short_type);
+	    break;
+	  case op_pop:
+	    pop32 ();
+	    break;
+	  case op_pop2:
+	    {
+	      type t = pop_raw ();
+	      if (! t.iswide ())
+		pop32 ();
+	    }
+	    break;
+	  case op_dup:
+	    {
+	      type t = pop32 ();
+	      push_type (t);
+	      push_type (t);
+	    }
+	    break;
+	  case op_dup_x1:
+	    {
+	      type t1 = pop32 ();
+	      type t2 = pop32 ();
+	      push_type (t1);
+	      push_type (t2);
+	      push_type (t1);
+	    }
+	    break;
+	  case op_dup_x2:
+	    {
+	      type t1 = pop32 ();
+	      type t2 = pop_raw ();
+	      if (! t2.iswide ())
+		{
+		  type t3 = pop32 ();
+		  push_type (t1);
+		  push_type (t3);
+		}
+	      else
+		push_type (t1);
+	      push_type (t2);
+	      push_type (t1);
+	    }
+	    break;
+	  case op_dup2:
+	    {
+	      type t = pop_raw ();
+	      if (! t.iswide ())
+		{
+		  type t2 = pop32 ();
+		  push_type (t2);
+		  push_type (t);
+		  push_type (t2);
+		}
+	      else
+		push_type (t);
+	      push_type (t);
+	    }
+	    break;
+	  case op_dup2_x1:
+	    {
+	      type t1 = pop_raw ();
+	      type t2 = pop32 ();
+	      if (! t1.iswide ())
+		{
+		  type t3 = pop32 ();
+		  push_type (t2);
+		  push_type (t1);
+		  push_type (t3);
+		}
+	      else
+		push_type (t1);
+	      push_type (t2);
+	      push_type (t1);
+	    }
+	    break;
+	  case op_dup2_x2:
+	    {
+	      type t1 = pop_raw ();
+	      if (t1.iswide ())
+		{
+		  type t2 = pop_raw ();
+		  if (t2.iswide ())
+		    {
+		      push_type (t1);
+		      push_type (t2);
+		    }
+		  else
+		    {
+		      type t3 = pop32 ();
+		      push_type (t1);
+		      push_type (t3);
+		      push_type (t2);
+		    }
+		  push_type (t1);
+		}
+	      else
+		{
+		  type t2 = pop32 ();
+		  type t3 = pop_raw ();
+		  if (t3.iswide ())
+		    {
+		      push_type (t2);
+		      push_type (t1);
+		    }
+		  else
+		    {
+		      type t4 = pop32 ();
+		      push_type (t2);
+		      push_type (t1);
+		      push_type (t4);
+		    }
+		  push_type (t3);
+		  push_type (t2);
+		  push_type (t1);
+		}
+	    }
+	    break;
+	  case op_swap:
+	    {
+	      type t1 = pop32 ();
+	      type t2 = pop32 ();
+	      push_type (t1);
+	      push_type (t2);
+	    }
+	    break;
+	  case op_iadd:
+	  case op_isub:
+	  case op_imul:
+	  case op_idiv:
+	  case op_irem:
+	  case op_ishl:
+	  case op_ishr:
+	  case op_iushr:
+	  case op_iand:
+	  case op_ior:
+	  case op_ixor:
+	    pop_type (int_type);
+	    push_type (pop_type (int_type));
+	    break;
+	  case op_ladd:
+	  case op_lsub:
+	  case op_lmul:
+	  case op_ldiv:
+	  case op_lrem:
+	  case op_land:
+	  case op_lor:
+	  case op_lxor:
+	    pop_type (long_type);
+	    push_type (pop_type (long_type));
+	    break;
+	  case op_lshl:
+	  case op_lshr:
+	  case op_lushr:
+	    pop_type (int_type);
+	    push_type (pop_type (long_type));
+	    break;
+	  case op_fadd:
+	  case op_fsub:
+	  case op_fmul:
+	  case op_fdiv:
+	  case op_frem:
+	    pop_type (float_type);
+	    push_type (pop_type (float_type));
+	    break;
+	  case op_dadd:
+	  case op_dsub:
+	  case op_dmul:
+	  case op_ddiv:
+	  case op_drem:
+	    pop_type (double_type);
+	    push_type (pop_type (double_type));
+	    break;
+	  case op_ineg:
+	  case op_i2b:
+	  case op_i2c:
+	  case op_i2s:
+	    push_type (pop_type (int_type));
+	    break;
+	  case op_lneg:
+	    push_type (pop_type (long_type));
+	    break;
+	  case op_fneg:
+	    push_type (pop_type (float_type));
+	    break;
+	  case op_dneg:
+	    push_type (pop_type (double_type));
+	    break;
+	  case op_iinc:
+	    get_variable (get_byte (), int_type);
+	    get_byte ();
+	    break;
+	  case op_i2l:
+	    pop_type (int_type);
+	    push_type (long_type);
+	    break;
+	  case op_i2f:
+	    pop_type (int_type);
+	    push_type (float_type);
+	    break;
+	  case op_i2d:
+	    pop_type (int_type);
+	    push_type (double_type);
+	    break;
+	  case op_l2i:
+	    pop_type (long_type);
+	    push_type (int_type);
+	    break;
+	  case op_l2f:
+	    pop_type (long_type);
+	    push_type (float_type);
+	    break;
+	  case op_l2d:
+	    pop_type (long_type);
+	    push_type (double_type);
+	    break;
+	  case op_f2i:
+	    pop_type (float_type);
+	    push_type (int_type);
+	    break;
+	  case op_f2l:
+	    pop_type (float_type);
+	    push_type (long_type);
+	    break;
+	  case op_f2d:
+	    pop_type (float_type);
+	    push_type (double_type);
+	    break;
+	  case op_d2i:
+	    pop_type (double_type);
+	    push_type (int_type);
+	    break;
+	  case op_d2l:
+	    pop_type (double_type);
+	    push_type (long_type);
+	    break;
+	  case op_d2f:
+	    pop_type (double_type);
+	    push_type (float_type);
+	    break;
+	  case op_lcmp:
+	    pop_type (long_type);
+	    pop_type (long_type);
+	    push_type (int_type);
+	    break;
+	  case op_fcmpl:
+	  case op_fcmpg:
+	    pop_type (float_type);
+	    pop_type (float_type);
+	    push_type (int_type);
+	    break;
+	  case op_dcmpl:
+	  case op_dcmpg:
+	    pop_type (double_type);
+	    pop_type (double_type);
+	    push_type (int_type);
+	    break;
+	  case op_ifeq:
+	  case op_ifne:
+	  case op_iflt:
+	  case op_ifge:
+	  case op_ifgt:
+	  case op_ifle:
+	    pop_type (int_type);
+	    push_jump (get_short ());
+	    break;
+	  case op_if_icmpeq:
+	  case op_if_icmpne:
+	  case op_if_icmplt:
+	  case op_if_icmpge:
+	  case op_if_icmpgt:
+	  case op_if_icmple:
+	    pop_type (int_type);
+	    pop_type (int_type);
+	    push_jump (get_short ());
+	    break;
+	  case op_if_acmpeq:
+	  case op_if_acmpne:
+	    pop_type (reference_type);
+	    pop_type (reference_type);
+	    push_jump (get_short ());
+	    break;
+	  case op_goto:
+	    push_jump (get_short ());
+	    invalidate_pc ();
+	    break;
+	  case op_jsr:
+	    handle_jsr_insn (get_short ());
+	    break;
+	  case op_ret:
+	    handle_ret_insn (get_byte ());
+	    break;
+	  case op_tableswitch:
+	    {
+	      pop_type (int_type);
+	      skip_padding ();
+	      push_jump (get_int ());
+	      jint low = get_int ();
+	      jint high = get_int ();
+	      // Already checked LOW -vs- HIGH.
+	      for (int i = low; i <= high; ++i)
+		push_jump (get_int ());
+	      invalidate_pc ();
+	    }
+	    break;
+
+	  case op_lookupswitch:
+	    {
+	      pop_type (int_type);
+	      skip_padding ();
+	      push_jump (get_int ());
+	      jint npairs = get_int ();
+	      // Already checked NPAIRS >= 0.
+	      jint lastkey = 0;
+	      for (int i = 0; i < npairs; ++i)
+		{
+		  jint key = get_int ();
+		  if (i > 0 && key <= lastkey)
+		    verify_fail ("lookupswitch pairs unsorted", start_PC);
+		  lastkey = key;
+		  push_jump (get_int ());
+		}
+	      invalidate_pc ();
+	    }
+	    break;
+	  case op_ireturn:
+	    check_return_type (pop_type (int_type));
+	    invalidate_pc ();
+	    break;
+	  case op_lreturn:
+	    check_return_type (pop_type (long_type));
+	    invalidate_pc ();
+	    break;
+	  case op_freturn:
+	    check_return_type (pop_type (float_type));
+	    invalidate_pc ();
+	    break;
+	  case op_dreturn:
+	    check_return_type (pop_type (double_type));
+	    invalidate_pc ();
+	    break;
+	  case op_areturn:
+	    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_getstatic:
+	    push_type (check_field_constant (get_ushort ()));
+	    break;
+	  case op_putstatic:
+	    pop_type (check_field_constant (get_ushort ()));
+	    break;
+	  case op_getfield:
+	    {
+	      type klass;
+	      type field = check_field_constant (get_ushort (), &klass);
+	      pop_type (klass);
+	      push_type (field);
+	    }
+	    break;
+	  case op_putfield:
+	    {
+	      type klass;
+	      type field = check_field_constant (get_ushort (), &klass, true);
+	      pop_type (field);
+	      pop_type (klass);
+	    }
+	    break;
+
+	  case op_invokevirtual:
+	  case op_invokespecial:
+	  case op_invokestatic:
+	  case op_invokeinterface:
+	    {
+	      _Jv_Utf8Const *method_name, *method_signature;
+	      type class_type
+		= check_method_constant (get_ushort (),
+					 opcode == op_invokeinterface,
+					 &method_name,
+					 &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)
+		{
+		  nargs = get_byte ();
+		  if (get_byte () != 0)
+		    verify_fail ("invokeinterface dummy byte is wrong");
+		}
+
+	      bool is_init = false;
+	      if (_Jv_equalUtf8Consts (method_name, gcj::init_name))
+		{
+		  is_init = true;
+		  if (opcode != op_invokespecial)
+		    verify_fail ("can't invoke <init>");
+		}
+	      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)
+		{
+		  // 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)
+		{
+		  type t = class_type;
+		  if (is_init)
+		    {
+		      // In this case the PC doesn't matter.
+		      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.
+		    }
+		  type raw = pop_raw ();
+		  if (! t.compatible (raw, this))
+		    verify_fail ("incompatible type on stack");
+
+		  if (is_init)
+		    current_state->set_initialized (raw.get_pc (),
+						    current_method->max_locals);
+		}
+
+	      type rt = compute_return_type (method_signature);
+	      if (! rt.isvoid ())
+		push_type (rt);
+	    }
+	    break;
+
+	  case op_new:
+	    {
+	      type t = check_class_constant (get_ushort ());
+	      if (t.isarray ())
+		verify_fail ("type is array");
+	      t.set_uninitialized (start_PC, this);
+	      push_type (t);
+	    }
+	    break;
+
+	  case op_newarray:
+	    {
+	      int atype = get_byte ();
+	      // We intentionally have chosen constants to make this
+	      // valid.
+	      if (atype < boolean_type || atype > long_type)
+		verify_fail ("type not primitive", start_PC);
+	      pop_type (int_type);
+	      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 (this));
+	    break;
+	  case op_arraylength:
+	    {
+	      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$, this));
+	    invalidate_pc ();
+	    break;
+	  case op_checkcast:
+	    pop_init_ref (reference_type);
+	    push_type (check_class_constant (get_ushort ()));
+	    break;
+	  case op_instanceof:
+	    pop_init_ref (reference_type);
+	    check_class_constant (get_ushort ());
+	    push_type (int_type);
+	    break;
+	  case op_monitorenter:
+	    pop_init_ref (reference_type);
+	    break;
+	  case op_monitorexit:
+	    pop_init_ref (reference_type);
+	    break;
+	  case op_wide:
+	    {
+	      switch (get_byte ())
+		{
+		case op_iload:
+		  push_type (get_variable (get_ushort (), int_type));
+		  break;
+		case op_lload:
+		  push_type (get_variable (get_ushort (), long_type));
+		  break;
+		case op_fload:
+		  push_type (get_variable (get_ushort (), float_type));
+		  break;
+		case op_dload:
+		  push_type (get_variable (get_ushort (), double_type));
+		  break;
+		case op_aload:
+		  push_type (get_variable (get_ushort (), reference_type));
+		  break;
+		case op_istore:
+		  set_variable (get_ushort (), pop_type (int_type));
+		  break;
+		case op_lstore:
+		  set_variable (get_ushort (), pop_type (long_type));
+		  break;
+		case op_fstore:
+		  set_variable (get_ushort (), pop_type (float_type));
+		  break;
+		case op_dstore:
+		  set_variable (get_ushort (), pop_type (double_type));
+		  break;
+		case op_astore:
+		  set_variable (get_ushort (), pop_init_ref (reference_type));
+		  break;
+		case op_ret:
+		  handle_ret_insn (get_short ());
+		  break;
+		case op_iinc:
+		  get_variable (get_ushort (), int_type);
+		  get_short ();
+		  break;
+		default:
+		  verify_fail ("unrecognized wide instruction", start_PC);
+		}
+	    }
+	    break;
+	  case op_multianewarray:
+	    {
+	      type atype = check_class_constant (get_ushort ());
+	      int dim = get_byte ();
+	      if (dim < 1)
+		verify_fail ("too few dimensions to multianewarray", start_PC);
+	      atype.verify_dimensions (dim, this);
+	      for (int i = 0; i < dim; ++i)
+		pop_type (int_type);
+	      push_type (atype);
+	    }
+	    break;
+	  case op_ifnull:
+	  case op_ifnonnull:
+	    pop_type (reference_type);
+	    push_jump (get_short ());
+	    break;
+	  case op_goto_w:
+	    push_jump (get_int ());
+	    invalidate_pc ();
+	    break;
+	  case op_jsr_w:
+	    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",
+			 start_PC);
+	  }
+      }
+  }
+
+public:
+
+  void verify_instructions ()
+  {
+    branch_prepass ();
+    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 ();
+    current_class = m->defining_class;
+
+    states = NULL;
+    flags = NULL;
+    utf8_list = NULL;
+    isect_list = NULL;
+  }
+
+  ~_Jv_BytecodeVerifier ()
+  {
+    if (flags)
+      _Jv_Free (flags);
+
+    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);
+      }
+  }
+};
+
+void
+_Jv_VerifyMethod (_Jv_InterpMethod *meth)
+{
+  _Jv_BytecodeVerifier v (meth);
+  v.verify_instructions ();
+}
+
+#endif	/* INTERPRETER */