Initial checkin of GCC 4.9.0 from trunk (r208799).

Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba

1 files changed, 2105 insertions, 0 deletions

diff --git a/gcc-4.9/libjava/link.cc b/gcc-4.9/libjava/link.cc
new file mode 100644
index 000000000..25114085b
--- /dev/null
+++ b/gcc-4.9/libjava/link.cc
@@ -0,0 +1,2105 @@
+// link.cc - Code for linking and resolving classes and pool entries.
+
+/* Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
+   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.  */
+
+/* Author: Kresten Krab Thorup <krab@gnu.org>  */
+
+#include <config.h>
+#include <platform.h>
+
+#include <stdio.h>
+
+#ifdef USE_LIBFFI
+#include <ffi.h>
+#endif
+
+#include <java-interp.h>
+
+// Set GC_DEBUG before including gc.h!
+#ifdef LIBGCJ_GC_DEBUG
+# define GC_DEBUG
+#endif
+#include <gc.h>
+
+#include <jvm.h>
+#include <gcj/cni.h>
+#include <string.h>
+#include <limits.h>
+#include <java-cpool.h>
+#include <execution.h>
+#ifdef INTERPRETER
+#include <jvmti.h>
+#include "jvmti-int.h"
+#endif
+#include <java/lang/Class.h>
+#include <java/lang/String.h>
+#include <java/lang/StringBuffer.h>
+#include <java/lang/Thread.h>
+#include <java/lang/InternalError.h>
+#include <java/lang/VirtualMachineError.h>
+#include <java/lang/VerifyError.h>
+#include <java/lang/NoSuchFieldError.h>
+#include <java/lang/NoSuchMethodError.h>
+#include <java/lang/ClassFormatError.h>
+#include <java/lang/IllegalAccessError.h>
+#include <java/lang/InternalError.h>
+#include <java/lang/AbstractMethodError.h>
+#include <java/lang/NoClassDefFoundError.h>
+#include <java/lang/IncompatibleClassChangeError.h>
+#include <java/lang/VerifyError.h>
+#include <java/lang/VMClassLoader.h>
+#include <java/lang/reflect/Modifier.h>
+#include <java/security/CodeSource.h>
+
+using namespace gcj;
+
+template<typename T>
+struct aligner
+{
+  char c;
+  T field;
+};
+
+#define ALIGNOF(TYPE) (offsetof (aligner<TYPE>, field))
+
+// This returns the alignment of a type as it would appear in a
+// structure.  This can be different from the alignment of the type
+// itself.  For instance on x86 double is 8-aligned but struct{double}
+// is 4-aligned.
+int
+_Jv_Linker::get_alignment_from_class (jclass klass)
+{
+  if (klass == JvPrimClass (byte))
+    return ALIGNOF (jbyte);
+  else if (klass == JvPrimClass (short))
+    return ALIGNOF (jshort);
+  else if (klass == JvPrimClass (int)) 
+    return ALIGNOF (jint);
+  else if (klass == JvPrimClass (long))
+    return ALIGNOF (jlong);
+  else if (klass == JvPrimClass (boolean))
+    return ALIGNOF (jboolean);
+  else if (klass == JvPrimClass (char))
+    return ALIGNOF (jchar);
+  else if (klass == JvPrimClass (float))
+    return ALIGNOF (jfloat);
+  else if (klass == JvPrimClass (double))
+    return ALIGNOF (jdouble);
+  else
+    return ALIGNOF (jobject);
+}
+
+void
+_Jv_Linker::resolve_field (_Jv_Field *field, java::lang::ClassLoader *loader)
+{
+  if (! field->isResolved ())
+    {
+      _Jv_Utf8Const *sig = (_Jv_Utf8Const *) field->type;
+      jclass type = _Jv_FindClassFromSignature (sig->chars(), loader);
+      if (type == NULL)
+	throw new java::lang::NoClassDefFoundError(field->name->toString());
+      field->type = type;
+      field->flags &= ~_Jv_FIELD_UNRESOLVED_FLAG;
+    }
+}
+
+// A helper for find_field that knows how to recursively search
+// superclasses and interfaces.
+_Jv_Field *
+_Jv_Linker::find_field_helper (jclass search, _Jv_Utf8Const *name,
+			       _Jv_Utf8Const *type_name, jclass type,
+			       jclass *declarer)
+{
+  while (search)
+    {
+      // From 5.4.3.2.  First search class itself.
+      for (int i = 0; i < search->field_count; ++i)
+	{
+	  _Jv_Field *field = &search->fields[i];
+	  if (! _Jv_equalUtf8Consts (field->name, name))
+	    continue;
+
+          // Checks for the odd situation where we were able to retrieve the
+          // field's class from signature but the resolution of the field itself
+          // failed which means a different class was resolved.
+          if (type != NULL)
+            {
+              try
+                {
+                  resolve_field (field, search->loader);
+                }
+              catch (java::lang::Throwable *exc)
+                {
+                  java::lang::LinkageError *le = new java::lang::LinkageError
+	            (JvNewStringLatin1 
+                      ("field type mismatch with different loaders"));
+
+                  le->initCause(exc);
+
+                  throw le;
+                }
+            }
+
+	  // Note that we compare type names and not types.  This is
+	  // bizarre, but we do it because we want to find a field
+	  // (and terminate the search) if it has the correct
+	  // descriptor -- but then later reject it if the class
+	  // loader check results in different classes.  We can't just
+	  // pass in the descriptor and check that way, because when
+	  // the field is already resolved there is no easy way to
+	  // find its descriptor again.
+	  if ((field->isResolved ()
+               ? _Jv_equalUtf8Classnames (type_name, field->type->name)
+               : _Jv_equalUtf8Classnames (type_name,
+                                          (_Jv_Utf8Const *) field->type)))
+	    {
+	      *declarer = search;
+	      return field;
+	    }
+	}
+
+      // Next search direct interfaces.
+      for (int i = 0; i < search->interface_count; ++i)
+	{
+	  _Jv_Field *result = find_field_helper (search->interfaces[i], name,
+						 type_name, type, declarer);
+	  if (result)
+	    return result;
+	}
+
+      // Now search superclass.
+      search = search->superclass;
+    }
+
+  return NULL;
+}
+
+bool
+_Jv_Linker::has_field_p (jclass search, _Jv_Utf8Const *field_name)
+{
+  for (int i = 0; i < search->field_count; ++i)
+    {
+      _Jv_Field *field = &search->fields[i];
+      if (_Jv_equalUtf8Consts (field->name, field_name))
+	return true;
+    }
+  return false;
+}
+
+// Find a field.
+// KLASS is the class that is requesting the field.
+// OWNER is the class in which the field should be found.
+// FIELD_TYPE_NAME is the type descriptor for the field.
+// Fill FOUND_CLASS with the address of the class in which the field
+// is actually declared.
+// This function does the class loader type checks, and
+// also access checks.  Returns the field, or throws an
+// exception on error.
+_Jv_Field *
+_Jv_Linker::find_field (jclass klass, jclass owner,
+			jclass *found_class,
+			_Jv_Utf8Const *field_name,
+			_Jv_Utf8Const *field_type_name)
+{
+  // FIXME: this allocates a _Jv_Utf8Const each time.  We should make
+  // it cheaper.
+  // Note: This call will resolve the primitive type names ("Z", "B", ...) to
+  // their Java counterparts ("boolean", "byte", ...) if accessed via
+  // field_type->name later.  Using these variants of the type name is in turn
+  // important for the find_field_helper function.  However if the class
+  // resolution failed then we can only use the already given type name.
+  jclass field_type 
+    = _Jv_FindClassFromSignatureNoException (field_type_name->chars(),
+                                             klass->loader);
+
+  _Jv_Field *the_field
+    = find_field_helper (owner, field_name,
+                         (field_type
+                           ? field_type->name :
+                             field_type_name ),
+                           field_type, found_class);
+
+  if (the_field == 0)
+    {
+      java::lang::StringBuffer *sb = new java::lang::StringBuffer();
+      sb->append(JvNewStringLatin1("field "));
+      sb->append(owner->getName());
+      sb->append(JvNewStringLatin1("."));
+      sb->append(_Jv_NewStringUTF(field_name->chars()));
+      sb->append(JvNewStringLatin1(" was not found."));
+      throw new java::lang::NoSuchFieldError (sb->toString());
+    }
+
+  // Accept it when the field's class could not be resolved.
+  if (field_type == NULL)
+    // Silently ignore that we were not able to retrieve the type to make it
+    // possible to run code which does not access this field.
+    return the_field;
+
+  if (_Jv_CheckAccess (klass, *found_class, the_field->flags))
+    {
+      // Note that the field returned by find_field_helper is always
+      // resolved.  However, we still use the constraint mechanism
+      // because this may affect other lookups.
+      _Jv_CheckOrCreateLoadingConstraint (field_type, (*found_class)->loader);
+    }
+  else
+    {
+      java::lang::StringBuffer *sb
+	= new java::lang::StringBuffer ();
+      sb->append(klass->getName());
+      sb->append(JvNewStringLatin1(": "));
+      sb->append((*found_class)->getName());
+      sb->append(JvNewStringLatin1("."));
+      sb->append(_Jv_NewStringUtf8Const (field_name));
+      throw new java::lang::IllegalAccessError(sb->toString());
+    }
+
+  return the_field;
+}
+
+// Check loading constraints for method.
+void
+_Jv_Linker::check_loading_constraints (_Jv_Method *method, jclass self_class,
+				       jclass other_class)
+{
+  JArray<jclass> *klass_args;
+  jclass klass_return;
+
+  _Jv_GetTypesFromSignature (method, self_class, &klass_args, &klass_return);
+  jclass *klass_arg = elements (klass_args);
+  java::lang::ClassLoader *found_loader = other_class->loader;
+
+  _Jv_CheckOrCreateLoadingConstraint (klass_return, found_loader);
+  for (int i = 0; i < klass_args->length; i++)
+    _Jv_CheckOrCreateLoadingConstraint (*(klass_arg++), found_loader);
+}
+
+_Jv_Method *
+_Jv_Linker::resolve_method_entry (jclass klass, jclass &found_class,
+				  int class_index, int name_and_type_index,
+				  bool init, bool is_iface)
+{
+  _Jv_Constants *pool = &klass->constants;
+  jclass owner = resolve_pool_entry (klass, class_index).clazz;
+
+  if (init && owner != klass)
+    _Jv_InitClass (owner);
+
+  _Jv_ushort name_index, type_index;
+  _Jv_loadIndexes (&pool->data[name_and_type_index],
+		   name_index,
+		   type_index);
+
+  _Jv_Utf8Const *method_name = pool->data[name_index].utf8;
+  _Jv_Utf8Const *method_signature = pool->data[type_index].utf8;
+
+  _Jv_Method *the_method = 0;
+  found_class = 0;
+
+  // We're going to cache a pointer to the _Jv_Method object
+  // when we find it.  So, to ensure this doesn't get moved from
+  // beneath us, we first put all the needed Miranda methods
+  // into the target class.
+  wait_for_state (klass, JV_STATE_LOADED);
+
+  // First search the class itself.
+  the_method = search_method_in_class (owner, klass,
+				       method_name, method_signature);
+
+  if (the_method != 0)
+    {
+      found_class = owner;
+      goto end_of_method_search;
+    }
+
+  // If we are resolving an interface method, search the
+  // interface's superinterfaces (A superinterface is not an
+  // interface's superclass - a superinterface is implemented by
+  // the interface).
+  if (is_iface)
+    {
+      _Jv_ifaces ifaces;
+      ifaces.count = 0;
+      ifaces.len = 4;
+      ifaces.list = (jclass *) _Jv_Malloc (ifaces.len
+					   * sizeof (jclass *));
+
+      get_interfaces (owner, &ifaces);
+
+      for (int i = 0; i < ifaces.count; i++)
+	{
+	  jclass cls = ifaces.list[i];
+	  the_method = search_method_in_class (cls, klass, method_name, 
+					       method_signature);
+	  if (the_method != 0)
+	    {
+	      found_class = cls;
+	      break;
+	    }
+	}
+
+      _Jv_Free (ifaces.list);
+
+      if (the_method != 0)
+	goto end_of_method_search;
+    }
+
+  // Finally, search superclasses. 
+  the_method = (search_method_in_superclasses 
+		(owner->getSuperclass (), klass, method_name, 
+		 method_signature, &found_class));
+  
+
+ end_of_method_search:
+  if (the_method == 0)
+    {
+      java::lang::StringBuffer *sb = new java::lang::StringBuffer();
+      sb->append(JvNewStringLatin1("method "));
+      sb->append(owner->getName());
+      sb->append(JvNewStringLatin1("."));
+      sb->append(_Jv_NewStringUTF(method_name->chars()));
+      sb->append(JvNewStringLatin1(" with signature "));
+      sb->append(_Jv_NewStringUTF(method_signature->chars()));
+      sb->append(JvNewStringLatin1(" was not found."));
+      throw new java::lang::NoSuchMethodError (sb->toString());
+    }
+
+  // if (found_class->loader != klass->loader), then we must actually
+  // check that the types of arguments correspond.  JVMS 5.4.3.3.
+  if (found_class->loader != klass->loader)
+    check_loading_constraints (the_method, klass, found_class);
+  
+  return the_method;
+}
+
+_Jv_Mutex_t _Jv_Linker::resolve_mutex;
+
+void
+_Jv_Linker::init (void)
+{
+  _Jv_MutexInit (&_Jv_Linker::resolve_mutex);
+}
+
+// Locking in resolve_pool_entry is somewhat subtle.  Constant
+// resolution is idempotent, so it doesn't matter if two threads
+// resolve the same entry.  However, it is important that we always
+// write the resolved flag and the data together, atomically.  It is
+// also important that we read them atomically.
+_Jv_word
+_Jv_Linker::resolve_pool_entry (jclass klass, int index, bool lazy)
+{
+  using namespace java::lang::reflect;
+
+  if (GC_base (klass) && klass->constants.data
+      && ! GC_base (klass->constants.data))
+    // If a class is heap-allocated but the constant pool is not this
+    // is a "new ABI" class, i.e. one where the initial constant pool
+    // is in the read-only data section of an object file.  Copy the
+    // initial constant pool from there to a new heap-allocated pool.
+    {
+      jsize count = klass->constants.size;
+      if (count)
+	{
+	  _Jv_word* constants
+	    = (_Jv_word*) _Jv_AllocRawObj (count * sizeof (_Jv_word));
+	  memcpy ((void*)constants,
+		  (void*)klass->constants.data,
+		  count * sizeof (_Jv_word));
+	  klass->constants.data = constants;
+	}
+    }
+
+  _Jv_Constants *pool = &klass->constants;
+
+  jbyte tags;
+  _Jv_word data;
+  tags = read_cpool_entry (&data, pool, index);
+
+  if ((tags & JV_CONSTANT_ResolvedFlag) != 0)
+    return data;
+
+  switch (tags & ~JV_CONSTANT_LazyFlag)
+    {
+    case JV_CONSTANT_Class:
+      {
+	_Jv_Utf8Const *name = data.utf8;
+
+	jclass found;
+	if (name->first() == '[')
+	  found = _Jv_FindClassFromSignatureNoException (name->chars(),
+		                                         klass->loader);
+        else
+	  found = _Jv_FindClassNoException (name, klass->loader);
+
+        // If the class could not be loaded a phantom class is created. Any
+        // function that deals with such a class but cannot do something useful
+        // with it should just throw a NoClassDefFoundError with the class'
+        // name.
+	if (! found)
+	  {
+	    if (lazy)
+	      {
+		found = _Jv_NewClass(name, NULL, NULL);
+		found->state = JV_STATE_PHANTOM;
+		tags |= JV_CONSTANT_ResolvedFlag;
+		data.clazz = found;
+		break;
+	      }
+	    else
+	      throw new java::lang::NoClassDefFoundError (name->toString());
+	  }
+
+	// Check accessibility, but first strip array types as
+	// _Jv_ClassNameSamePackage can't handle arrays.
+	jclass check;
+	for (check = found;
+	     check && check->isArray();
+	     check = check->getComponentType())
+	  ;
+	if ((found->accflags & Modifier::PUBLIC) == Modifier::PUBLIC
+	    || (_Jv_ClassNameSamePackage (check->name,
+					  klass->name)))
+	  {
+	    data.clazz = found;
+	    tags |= JV_CONSTANT_ResolvedFlag;
+	  }
+	else
+	  {
+	    java::lang::StringBuffer *sb = new java::lang::StringBuffer ();
+	    sb->append(klass->getName());
+	    sb->append(JvNewStringLatin1(" can't access class "));
+	    sb->append(found->getName());
+	    throw new java::lang::IllegalAccessError(sb->toString());
+	  }
+      }
+      break;
+
+    case JV_CONSTANT_String:
+      {
+	jstring str;
+	str = _Jv_NewStringUtf8Const (data.utf8);
+	data.o = str;
+	tags |= JV_CONSTANT_ResolvedFlag;
+      }
+      break;
+
+    case JV_CONSTANT_Fieldref:
+      {
+	_Jv_ushort class_index, name_and_type_index;
+	_Jv_loadIndexes (&data,
+			 class_index,
+			 name_and_type_index);
+	jclass owner = (resolve_pool_entry (klass, class_index, true)).clazz;
+
+        // If a phantom class was resolved our field reference is
+        // unusable because of the missing class.
+        if (owner->state == JV_STATE_PHANTOM)
+          throw new java::lang::NoClassDefFoundError(owner->getName());
+
+	// We don't initialize 'owner', but we do make sure that its
+	// fields exist.
+	wait_for_state (owner, JV_STATE_PREPARED);
+
+	_Jv_ushort name_index, type_index;
+	_Jv_loadIndexes (&pool->data[name_and_type_index],
+			 name_index,
+			 type_index);
+
+	_Jv_Utf8Const *field_name = pool->data[name_index].utf8;
+	_Jv_Utf8Const *field_type_name = pool->data[type_index].utf8;
+
+	jclass found_class = 0;
+	_Jv_Field *the_field = find_field (klass, owner, 
+					   &found_class,
+					   field_name,
+					   field_type_name);
+	// Initialize the field's declaring class, not its qualifying
+	// class.
+	_Jv_InitClass (found_class);
+	data.field = the_field;
+	tags |= JV_CONSTANT_ResolvedFlag;
+      }
+      break;
+
+    case JV_CONSTANT_Methodref:
+    case JV_CONSTANT_InterfaceMethodref:
+      {
+	_Jv_ushort class_index, name_and_type_index;
+	_Jv_loadIndexes (&data,
+			 class_index,
+			 name_and_type_index);
+
+	_Jv_Method *the_method;
+	jclass found_class;
+	the_method = resolve_method_entry (klass, found_class,
+					   class_index, name_and_type_index,
+					   true,
+					   tags == JV_CONSTANT_InterfaceMethodref);
+      
+	data.rmethod
+	  = klass->engine->resolve_method(the_method,
+					  found_class,
+					  ((the_method->accflags
+					    & Modifier::STATIC) != 0));
+	tags |= JV_CONSTANT_ResolvedFlag;
+      }
+      break;
+    }
+
+  write_cpool_entry (data, tags, pool, index);
+
+  return data;
+}
+
+// This function is used to lazily locate superclasses and
+// superinterfaces.  This must be called with the class lock held.
+void
+_Jv_Linker::resolve_class_ref (jclass klass, jclass *classref)
+{
+  jclass ret = *classref;
+
+  // If superclass looks like a constant pool entry, resolve it now.
+  if (ret && (uaddr) ret < (uaddr) klass->constants.size)
+    {
+      if (klass->state < JV_STATE_LINKED)
+	{
+	  _Jv_Utf8Const *name = klass->constants.data[(uaddr) *classref].utf8;
+	  ret = _Jv_FindClass (name, klass->loader);
+	  if (! ret)
+	    {
+	      throw new java::lang::NoClassDefFoundError (name->toString());
+	    }
+	}
+      else
+	ret = klass->constants.data[(uaddr) classref].clazz;
+      *classref = ret;
+    }
+}
+
+// Find a method declared in the cls that is referenced from klass and
+// perform access checks if CHECK_PERMS is true.
+_Jv_Method *
+_Jv_Linker::search_method_in_class (jclass cls, jclass klass, 
+				    _Jv_Utf8Const *method_name, 
+				    _Jv_Utf8Const *method_signature,
+				    bool check_perms)
+{
+  using namespace java::lang::reflect;
+
+  for (int i = 0;  i < cls->method_count;  i++)
+    {
+      _Jv_Method *method = &cls->methods[i];
+      if (   (!_Jv_equalUtf8Consts (method->name,
+				    method_name))
+	  || (!_Jv_equalUtf8Consts (method->signature,
+				    method_signature)))
+	continue;
+
+      if (!check_perms || _Jv_CheckAccess (klass, cls, method->accflags))
+	return method;
+      else
+	{
+	  java::lang::StringBuffer *sb = new java::lang::StringBuffer();
+	  sb->append(klass->getName());
+	  sb->append(JvNewStringLatin1(": "));
+	  sb->append(cls->getName());
+	  sb->append(JvNewStringLatin1("."));
+	  sb->append(_Jv_NewStringUTF(method_name->chars()));
+	  sb->append(_Jv_NewStringUTF(method_signature->chars()));
+	  throw new java::lang::IllegalAccessError (sb->toString());
+	}
+    }
+  return 0;
+}
+
+// Like search_method_in_class, but work our way up the superclass
+// chain.
+_Jv_Method *
+_Jv_Linker::search_method_in_superclasses (jclass cls, jclass klass, 
+					   _Jv_Utf8Const *method_name, 
+					   _Jv_Utf8Const *method_signature,
+					   jclass *found_class, bool check_perms)
+{
+  _Jv_Method *the_method = NULL;
+
+  for ( ; cls != 0; cls = cls->getSuperclass ())
+    {
+      the_method = search_method_in_class (cls, klass, method_name,
+					   method_signature, check_perms);
+      if (the_method != 0)
+	{
+	  if (found_class)
+	    *found_class = cls;
+	  break;
+	}
+    }
+  
+  return the_method;
+}
+
+#define INITIAL_IOFFSETS_LEN 4
+#define INITIAL_IFACES_LEN 4
+
+static _Jv_IDispatchTable null_idt = {SHRT_MAX, 0, {}};
+
+// Generate tables for constant-time assignment testing and interface
+// method lookup. This implements the technique described by Per Bothner
+// <per@bothner.com> on the java-discuss mailing list on 1999-09-02:
+// http://gcc.gnu.org/ml/java/1999-q3/msg00377.html
+void
+_Jv_Linker::prepare_constant_time_tables (jclass klass)
+{  
+  if (klass->isPrimitive () || klass->isInterface ())
+    return;
+
+  // Short-circuit in case we've been called already.
+  if ((klass->idt != NULL) || klass->depth != 0)
+    return;
+
+  // Calculate the class depth and ancestor table. The depth of a class 
+  // is how many "extends" it is removed from Object. Thus the depth of 
+  // java.lang.Object is 0, but the depth of java.io.FilterOutputStream 
+  // is 2. Depth is defined for all regular and array classes, but not 
+  // interfaces or primitive types.
+   
+  jclass klass0 = klass;
+  jboolean has_interfaces = false;
+  while (klass0 != &java::lang::Object::class$)
+    {
+      if (klass0->interface_count)
+	has_interfaces = true;
+      klass0 = klass0->superclass;
+      klass->depth++;
+    }
+
+  // We do class member testing in constant time by using a small table 
+  // of all the ancestor classes within each class. The first element is 
+  // a pointer to the current class, and the rest are pointers to the 
+  // classes ancestors, ordered from the current class down by decreasing 
+  // depth. We do not include java.lang.Object in the table of ancestors, 
+  // since it is redundant.  Note that the classes pointed to by
+  // 'ancestors' will always be reachable by other paths.
+
+  klass->ancestors = (jclass *) _Jv_AllocBytes (klass->depth
+						* sizeof (jclass));
+  klass0 = klass;
+  for (int index = 0; index < klass->depth; index++)
+    {
+      klass->ancestors[index] = klass0;
+      klass0 = klass0->superclass;
+    }
+
+  if ((klass->accflags & java::lang::reflect::Modifier::ABSTRACT) != 0)
+    return;
+
+  // Optimization: If class implements no interfaces, use a common
+  // predefined interface table.
+  if (!has_interfaces)
+    {
+      klass->idt = &null_idt;
+      return;
+    }
+
+  _Jv_ifaces ifaces;
+  ifaces.count = 0;
+  ifaces.len = INITIAL_IFACES_LEN;
+  ifaces.list = (jclass *) _Jv_Malloc (ifaces.len * sizeof (jclass *));
+
+  int itable_size = get_interfaces (klass, &ifaces);
+
+  if (ifaces.count > 0)
+    {
+      // The classes pointed to by the itable will always be reachable
+      // via other paths.
+      int idt_bytes = sizeof (_Jv_IDispatchTable) + (itable_size 
+						     * sizeof (void *));
+      klass->idt = (_Jv_IDispatchTable *) _Jv_AllocBytes (idt_bytes);
+      klass->idt->itable_length = itable_size;
+
+      jshort *itable_offsets = 
+	(jshort *) _Jv_Malloc (ifaces.count * sizeof (jshort));
+
+      generate_itable (klass, &ifaces, itable_offsets);
+
+      jshort cls_iindex = find_iindex (ifaces.list, itable_offsets,
+				       ifaces.count);
+
+      for (int i = 0; i < ifaces.count; i++)
+	{
+	  ifaces.list[i]->ioffsets[cls_iindex] = itable_offsets[i];
+	}
+
+      klass->idt->iindex = cls_iindex;	    
+
+      _Jv_Free (ifaces.list);
+      _Jv_Free (itable_offsets);
+    }
+  else 
+    {
+      klass->idt->iindex = SHRT_MAX;
+    }
+}
+
+// Return index of item in list, or -1 if item is not present.
+inline jshort
+_Jv_Linker::indexof (void *item, void **list, jshort list_len)
+{
+  for (int i=0; i < list_len; i++)
+    {
+      if (list[i] == item)
+        return i;
+    }
+  return -1;
+}
+
+// Find all unique interfaces directly or indirectly implemented by klass.
+// Returns the size of the interface dispatch table (itable) for klass, which 
+// is the number of unique interfaces plus the total number of methods that 
+// those interfaces declare. May extend ifaces if required.
+jshort
+_Jv_Linker::get_interfaces (jclass klass, _Jv_ifaces *ifaces)
+{
+  jshort result = 0;
+  
+  for (int i = 0; i < klass->interface_count; i++)
+    {
+      jclass iface = klass->interfaces[i];
+
+      /* Make sure interface is linked.  */
+      wait_for_state(iface, JV_STATE_LINKED);
+
+      if (indexof (iface, (void **) ifaces->list, ifaces->count) == -1)
+        {
+	  if (ifaces->count + 1 >= ifaces->len)
+	    {
+	      /* Resize ifaces list */
+	      ifaces->len = ifaces->len * 2;
+	      ifaces->list
+		= (jclass *) _Jv_Realloc (ifaces->list,
+					  ifaces->len * sizeof(jclass));
+	    }
+	  ifaces->list[ifaces->count] = iface;
+	  ifaces->count++;
+
+	  result += get_interfaces (klass->interfaces[i], ifaces);
+	}
+    }
+
+  if (klass->isInterface())
+    {
+      // We want to add 1 plus the number of interface methods here.
+      // But, we take special care to skip <clinit>.
+      ++result;
+      for (int i = 0; i < klass->method_count; ++i)
+	{
+	  if (klass->methods[i].name->first() != '<')
+	    ++result;
+	}
+    }
+  else if (klass->superclass)
+    result += get_interfaces (klass->superclass, ifaces);
+  return result;
+}
+
+// Fill out itable in klass, resolving method declarations in each ifaces.
+// itable_offsets is filled out with the position of each iface in itable,
+// such that itable[itable_offsets[n]] == ifaces.list[n].
+void
+_Jv_Linker::generate_itable (jclass klass, _Jv_ifaces *ifaces,
+			       jshort *itable_offsets)
+{
+  void **itable = klass->idt->itable;
+  jshort itable_pos = 0;
+
+  for (int i = 0; i < ifaces->count; i++)
+    { 
+      jclass iface = ifaces->list[i];
+      itable_offsets[i] = itable_pos;
+      itable_pos = append_partial_itable (klass, iface, itable, itable_pos);
+
+      /* Create ioffsets table for iface */
+      if (iface->ioffsets == NULL)
+	{
+	  // The first element of ioffsets is its length (itself included).
+	  jshort *ioffsets = (jshort *) _Jv_AllocBytes (INITIAL_IOFFSETS_LEN
+							* sizeof (jshort));
+	  ioffsets[0] = INITIAL_IOFFSETS_LEN;
+	  for (int i = 1; i < INITIAL_IOFFSETS_LEN; i++)
+	    ioffsets[i] = -1;
+
+	  iface->ioffsets = ioffsets;
+	}
+    }
+}
+
+// Format method name for use in error messages.
+jstring
+_Jv_GetMethodString (jclass klass, _Jv_Method *meth,
+		     jclass derived)
+{
+  using namespace java::lang;
+  StringBuffer *buf = new StringBuffer (klass->name->toString());
+  buf->append (jchar ('.'));
+  buf->append (meth->name->toString());
+  buf->append ((jchar) ' ');
+  buf->append (meth->signature->toString());
+  if (derived)
+    {
+      buf->append(JvNewStringLatin1(" in "));
+      buf->append(derived->name->toString());
+    }
+  return buf->toString();
+}
+
+void
+_Jv_ThrowNoSuchMethodError ()
+{
+  throw new java::lang::NoSuchMethodError;
+}
+
+#if defined USE_LIBFFI && FFI_CLOSURES && defined(INTERPRETER)
+// A function whose invocation is prepared using libffi. It gets called
+// whenever a static method of a missing class is invoked. The data argument
+// holds a reference to a String denoting the missing class.
+// The prepared function call is stored in a class' atable.
+void
+_Jv_ThrowNoClassDefFoundErrorTrampoline(ffi_cif *,
+                                        void *,
+                                        void **,
+                                        void *data)
+{
+  throw new java::lang::NoClassDefFoundError(
+    _Jv_NewStringUtf8Const((_Jv_Utf8Const *) data));
+}
+#else
+// A variant of the NoClassDefFoundError throwing method that can
+// be used without libffi.
+void
+_Jv_ThrowNoClassDefFoundError()
+{
+  throw new java::lang::NoClassDefFoundError();
+}
+#endif
+
+// Throw a NoSuchFieldError.  Called by compiler-generated code when
+// an otable entry is zero.  OTABLE_INDEX is the index in the caller's
+// otable that refers to the missing field.  This index may be used to
+// print diagnostic information about the field.
+void
+_Jv_ThrowNoSuchFieldError (int /* otable_index */)
+{
+  throw new java::lang::NoSuchFieldError;
+}
+
+// This is put in empty vtable slots.
+void
+_Jv_ThrowAbstractMethodError ()
+{
+  throw new java::lang::AbstractMethodError();
+}
+
+// Each superinterface of a class (i.e. each interface that the class
+// directly or indirectly implements) has a corresponding "Partial
+// Interface Dispatch Table" whose size is (number of methods + 1) words.
+// The first word is a pointer to the interface (i.e. the java.lang.Class
+// instance for that interface).  The remaining words are pointers to the
+// actual methods that implement the methods declared in the interface,
+// in order of declaration.
+//
+// Append partial interface dispatch table for "iface" to "itable", at
+// position itable_pos.
+// Returns the offset at which the next partial ITable should be appended.
+jshort
+_Jv_Linker::append_partial_itable (jclass klass, jclass iface,
+				   void **itable, jshort pos)
+{
+  using namespace java::lang::reflect;
+
+  itable[pos++] = (void *) iface;
+  _Jv_Method *meth;
+  
+  for (int j=0; j < iface->method_count; j++)
+    {
+      // Skip '<clinit>' here.
+      if (iface->methods[j].name->first() == '<')
+	continue;
+
+      meth = NULL;
+      jclass cl;
+      for (cl = klass; cl; cl = cl->getSuperclass())
+        {
+	  meth = _Jv_GetMethodLocal (cl, iface->methods[j].name,
+				     iface->methods[j].signature);
+		 
+	  if (meth)
+	    break;
+	}
+
+      if (meth)
+        {
+	  if ((meth->accflags & Modifier::STATIC) != 0)
+	    throw new java::lang::IncompatibleClassChangeError
+	      (_Jv_GetMethodString (klass, meth));
+	  if ((meth->accflags & Modifier::PUBLIC) == 0)
+	    throw new java::lang::IllegalAccessError
+	      (_Jv_GetMethodString (klass, meth));
+
+ 	  if ((meth->accflags & Modifier::ABSTRACT) != 0)
+	    itable[pos] = (void *) &_Jv_ThrowAbstractMethodError;
+	  else
+	    itable[pos] = meth->ncode;
+
+	  if (cl->loader != iface->loader)
+	    check_loading_constraints (meth, cl, iface);
+	}
+      else
+        {
+	  // The method doesn't exist in klass. Binary compatibility rules
+	  // permit this, so we delay the error until runtime using a pointer
+	  // to a method which throws an exception.
+	  itable[pos] = (void *) _Jv_ThrowNoSuchMethodError;
+	}
+      pos++;
+    }
+    
+  return pos;
+}
+
+static _Jv_Mutex_t iindex_mutex;
+static bool iindex_mutex_initialized = false;
+
+// We need to find the correct offset in the Class Interface Dispatch 
+// Table for a given interface. Once we have that, invoking an interface 
+// method just requires combining the Method's index in the interface 
+// (known at compile time) to get the correct method.  Doing a type test 
+// (cast or instanceof) is the same problem: Once we have a possible Partial 
+// Interface Dispatch Table, we just compare the first element to see if it 
+// matches the desired interface. So how can we find the correct offset?  
+// Our solution is to keep a vector of candiate offsets in each interface 
+// (ioffsets), and in each class we have an index (idt->iindex) used to
+// select the correct offset from ioffsets.
+//
+// Calculate and return iindex for a new class. 
+// ifaces is a vector of num interfaces that the class implements.
+// offsets[j] is the offset in the interface dispatch table for the
+// interface corresponding to ifaces[j].
+// May extend the interface ioffsets if required.
+jshort
+_Jv_Linker::find_iindex (jclass *ifaces, jshort *offsets, jshort num)
+{
+  int i;
+  int j;
+  
+  // Acquire a global lock to prevent itable corruption in case of multiple 
+  // classes that implement an intersecting set of interfaces being linked
+  // simultaneously. We can assume that the mutex will be initialized
+  // single-threaded.
+  if (! iindex_mutex_initialized)
+    {
+      _Jv_MutexInit (&iindex_mutex);
+      iindex_mutex_initialized = true;
+    }
+  
+  _Jv_MutexLock (&iindex_mutex);
+  
+  for (i=1;; i++)  /* each potential position in ioffsets */
+    {
+      for (j=0;; j++)  /* each iface */
+        {
+	  if (j >= num)
+	    goto found;
+	  if (i >= ifaces[j]->ioffsets[0])
+	    continue;
+	  int ioffset = ifaces[j]->ioffsets[i];
+	  /* We can potentially share this position with another class. */
+	  if (ioffset >= 0 && ioffset != offsets[j])
+	    break; /* Nope. Try next i. */	  
+	}
+    }
+  found:
+  for (j = 0; j < num; j++)
+    {
+      int len = ifaces[j]->ioffsets[0];
+      if (i >= len) 
+	{
+	  // Resize ioffsets.
+	  int newlen = 2 * len;
+	  if (i >= newlen)
+	    newlen = i + 3;
+
+	  jshort *old_ioffsets = ifaces[j]->ioffsets;
+	  jshort *new_ioffsets = (jshort *) _Jv_AllocBytes (newlen
+							    * sizeof(jshort));
+	  memcpy (&new_ioffsets[1], &old_ioffsets[1],
+		  (len - 1) * sizeof (jshort));
+	  new_ioffsets[0] = newlen;
+
+	  while (len < newlen)
+	    new_ioffsets[len++] = -1;
+	  
+	  ifaces[j]->ioffsets = new_ioffsets;
+	}
+      ifaces[j]->ioffsets[i] = offsets[j];
+    }
+
+  _Jv_MutexUnlock (&iindex_mutex);
+
+  return i;
+}
+
+#if defined USE_LIBFFI && FFI_CLOSURES && defined(INTERPRETER)
+// We use a structure of this type to store the closure that
+// represents a missing method.
+struct method_closure
+{
+  // This field must come first, since the address of this field will
+  // be the same as the address of the overall structure.  This is due
+  // to disabling interior pointers in the GC.
+  ffi_closure closure;
+  _Jv_ClosureList list;
+  ffi_cif cif;
+  ffi_type *arg_types[1];
+};
+
+void *
+_Jv_Linker::create_error_method (_Jv_Utf8Const *class_name, jclass klass)
+{
+  void *code;
+  method_closure *closure
+    = (method_closure *)ffi_closure_alloc (sizeof (method_closure), &code);
+
+  closure->arg_types[0] = &ffi_type_void;
+
+  // Initializes the cif and the closure.  If that worked the closure
+  // is returned and can be used as a function pointer in a class'
+  // atable.
+  if (   ffi_prep_cif (&closure->cif,
+                       FFI_DEFAULT_ABI,
+                       1,
+                       &ffi_type_void,
+		       closure->arg_types) == FFI_OK
+      && ffi_prep_closure_loc (&closure->closure,
+			       &closure->cif,
+			       _Jv_ThrowNoClassDefFoundErrorTrampoline,
+			       class_name,
+			       code) == FFI_OK)
+    {
+      closure->list.registerClosure (klass, closure);
+      return code;
+    }
+  else
+    {
+      ffi_closure_free (closure);
+      java::lang::StringBuffer *buffer = new java::lang::StringBuffer();
+      buffer->append(JvNewStringLatin1("Error setting up FFI closure"
+				       " for static method of"
+				       " missing class: "));
+      buffer->append (_Jv_NewStringUtf8Const(class_name));
+      throw new java::lang::InternalError(buffer->toString());
+    }
+}
+#else
+void *
+_Jv_Linker::create_error_method (_Jv_Utf8Const *, jclass)
+{
+  // Codepath for platforms which do not support (or want) libffi.
+  // You have to accept that it is impossible to provide the name
+  // of the missing class then.
+  return (void *) _Jv_ThrowNoClassDefFoundError;
+}
+#endif // USE_LIBFFI && FFI_CLOSURES
+
+// Functions for indirect dispatch (symbolic virtual binding) support.
+
+// There are three tables, atable otable and itable.  atable is an
+// array of addresses, and otable is an array of offsets, and these
+// are used for static and virtual members respectively.  itable is an
+// array of pairs {address, index} where each address is a pointer to
+// an interface.
+
+// {a,o,i}table_syms is an array of _Jv_MethodSymbols.  Each such
+// symbol is a tuple of {classname, member name, signature}.
+
+// Set this to true to enable debugging of indirect dispatch tables/linking.
+static bool debug_link = false;
+
+// link_symbol_table() scans these two arrays and fills in the
+// corresponding atable and otable with the addresses of static
+// members and the offsets of virtual members.
+
+// The offset (in bytes) for each resolved method or field is placed
+// at the corresponding position in the virtual method offset table
+// (klass->otable). 
+
+// This must be called while holding the class lock.
+
+void
+_Jv_Linker::link_symbol_table (jclass klass)
+{
+  int index = 0;
+  _Jv_MethodSymbol sym;
+  if (klass->otable == NULL
+      || klass->otable->state != 0)
+    goto atable;
+   
+  klass->otable->state = 1;
+
+  if (debug_link)
+    fprintf (stderr, "Fixing up otable in %s:\n", klass->name->chars());
+  for (index = 0;
+       (sym = klass->otable_syms[index]).class_name != NULL;
+       ++index)
+    {
+      jclass target_class = _Jv_FindClass (sym.class_name, klass->loader);
+      _Jv_Method *meth = NULL;            
+
+      _Jv_Utf8Const *signature = sym.signature;
+      uaddr special;
+      maybe_adjust_signature (signature, special);
+
+      if (target_class == NULL)
+	throw new java::lang::NoClassDefFoundError 
+	  (_Jv_NewStringUTF (sym.class_name->chars()));
+
+      // We're looking for a field or a method, and we can tell
+      // which is needed by looking at the signature.
+      if (signature->first() == '(' && signature->len() >= 2)
+	{
+	  // Looks like someone is trying to invoke an interface method
+	  if (target_class->isInterface())
+	    {
+	      using namespace java::lang;
+	      StringBuffer *sb = new StringBuffer();
+	      sb->append(JvNewStringLatin1("found interface "));
+	      sb->append(target_class->getName());
+	      sb->append(JvNewStringLatin1(" when searching for a class"));
+	      throw new VerifyError(sb->toString());
+	    }
+
+ 	  // If the target class does not have a vtable_method_count yet, 
+	  // then we can't tell the offsets for its methods, so we must lay 
+	  // it out now.
+	  wait_for_state(target_class, JV_STATE_PREPARED);
+
+	  try
+	    {
+	      meth = (search_method_in_superclasses 
+		      (target_class, klass, sym.name, signature, 
+		       NULL, special == 0));
+	    }
+	  catch (::java::lang::IllegalAccessError *e)
+	    {
+	    }
+
+	  // Every class has a throwNoSuchMethodErrorIndex method that
+	  // it inherits from java.lang.Object.  Find its vtable
+	  // offset.
+	  static int throwNoSuchMethodErrorIndex;
+	  if (throwNoSuchMethodErrorIndex == 0)
+	    {
+	      Utf8Const* name 
+		= _Jv_makeUtf8Const ("throwNoSuchMethodError", 
+				     strlen ("throwNoSuchMethodError"));
+	      _Jv_Method* meth
+		= _Jv_LookupDeclaredMethod (&java::lang::Object::class$, 
+					    name, gcj::void_signature);
+	      throwNoSuchMethodErrorIndex 
+		= _Jv_VTable::idx_to_offset (meth->index);
+	    }
+	  
+	  // If we don't find a nonstatic method, insert the
+	  // vtable index of Object.throwNoSuchMethodError().
+	  // This defers the missing method error until an attempt
+	  // is made to execute it.	  
+	  {
+	    int offset;
+	    
+	    if (meth != NULL)
+	      offset = _Jv_VTable::idx_to_offset (meth->index);
+	    else
+	      offset = throwNoSuchMethodErrorIndex;		    
+	    
+	    if (offset == -1)
+	      JvFail ("Bad method index");
+	    JvAssert (meth->index < target_class->vtable_method_count);
+	    
+	    klass->otable->offsets[index] = offset;
+	  }
+
+	  if (debug_link)
+	    fprintf (stderr, "  offsets[%d] = %d (class %s@%p : %s(%s))\n",
+		     (int)index,
+		     (int)klass->otable->offsets[index],
+		     (const char*)target_class->name->chars(),
+		     target_class,
+		     (const char*)sym.name->chars(),
+		     (const char*)signature->chars());
+	  continue;
+	}
+
+      // Try fields.
+      {
+	wait_for_state(target_class, JV_STATE_PREPARED);
+	jclass found_class;
+	_Jv_Field *the_field = NULL;
+	try
+	  {
+	    the_field = find_field (klass, target_class, &found_class,
+				    sym.name, signature);
+	    if ((the_field->flags & java::lang::reflect::Modifier::STATIC))
+	      throw new java::lang::IncompatibleClassChangeError;
+	    else
+	      klass->otable->offsets[index] = the_field->u.boffset;
+	  }
+	catch (java::lang::NoSuchFieldError *err)
+	  {
+	    klass->otable->offsets[index] = 0;
+	  }
+      }
+    }
+
+ atable:
+  if (klass->atable == NULL || klass->atable->state != 0)
+    goto itable;
+
+  klass->atable->state = 1;
+
+  for (index = 0;
+       (sym = klass->atable_syms[index]).class_name != NULL;
+       ++index)
+    {
+      jclass target_class =
+        _Jv_FindClassNoException (sym.class_name, klass->loader);
+
+      _Jv_Method *meth = NULL;            
+
+      _Jv_Utf8Const *signature = sym.signature;
+      uaddr special;
+      maybe_adjust_signature (signature, special);
+
+      // ??? Setting this pointer to null will at least get us a
+      // NullPointerException
+      klass->atable->addresses[index] = NULL;
+
+      bool use_error_method = false;
+
+      // If the target class is missing we prepare a function call
+      // that throws a NoClassDefFoundError and store the address of
+      // that newly prepared method in the atable. The user can run
+      // code in classes where the missing class is part of the
+      // execution environment as long as it is never referenced.
+      if (target_class == NULL)
+	use_error_method = true;
+      // We're looking for a static field or a static method, and we
+      // can tell which is needed by looking at the signature.
+      else if (signature->first() == '(' && signature->len() >= 2)
+	{
+ 	  // If the target class does not have a vtable_method_count yet, 
+	  // then we can't tell the offsets for its methods, so we must lay 
+	  // it out now.
+	  wait_for_state (target_class, JV_STATE_PREPARED);
+
+	  // Interface methods cannot have bodies.
+	  if (target_class->isInterface())
+	    {
+	      using namespace java::lang;
+	      StringBuffer *sb = new StringBuffer();
+	      sb->append(JvNewStringLatin1("class "));
+	      sb->append(target_class->getName());
+	      sb->append(JvNewStringLatin1(" is an interface: "
+					   "class expected"));
+	      throw new VerifyError(sb->toString());
+	    }
+
+	  try
+	    {
+	      meth = (search_method_in_superclasses 
+		      (target_class, klass, sym.name, signature, 
+		       NULL, special == 0));
+	    }
+	  catch (::java::lang::IllegalAccessError *e)
+	    {
+	    }
+
+	  if (meth != NULL)
+	    {
+	      if (meth->ncode) // Maybe abstract?
+		{
+		  klass->atable->addresses[index] = meth->ncode;
+		  if (debug_link)
+		    fprintf (stderr, "  addresses[%d] = %p (class %s@%p : %s(%s))\n",
+			     index,
+			     &klass->atable->addresses[index],
+			     (const char*)target_class->name->chars(),
+			     klass,
+			     (const char*)sym.name->chars(),
+			     (const char*)signature->chars());
+		}
+	    }
+	  else
+	    use_error_method = true;
+
+	  if (use_error_method)
+	    klass->atable->addresses[index]
+	      = create_error_method(sym.class_name, klass);
+
+	  continue;
+	}
+
+
+      // Try fields only if the target class exists.
+      if (target_class != NULL)
+      {
+	wait_for_state(target_class, JV_STATE_PREPARED);
+	jclass found_class;
+	_Jv_Field *the_field = find_field (klass, target_class, &found_class,
+					   sym.name, signature);
+	if ((the_field->flags & java::lang::reflect::Modifier::STATIC))
+	  klass->atable->addresses[index] = the_field->u.addr;
+	else
+	  throw new java::lang::IncompatibleClassChangeError;
+      }
+    }
+
+ itable:
+  if (klass->itable == NULL
+      || klass->itable->state != 0)
+    return;
+
+  klass->itable->state = 1;
+
+  for (index = 0;
+       (sym = klass->itable_syms[index]).class_name != NULL; 
+       ++index)
+    {
+      jclass target_class = _Jv_FindClass (sym.class_name, klass->loader);
+
+      _Jv_Utf8Const *signature = sym.signature;
+      uaddr special;
+      maybe_adjust_signature (signature, special);
+
+      jclass cls;
+      int i;
+
+      wait_for_state(target_class, JV_STATE_LOADED);
+      bool found = _Jv_getInterfaceMethod (target_class, cls, i,
+					   sym.name, signature);
+
+      if (found)
+	{
+	  klass->itable->addresses[index * 2] = cls;
+	  klass->itable->addresses[index * 2 + 1] = (void *)(unsigned long) i;
+	  if (debug_link)
+	    {
+	      fprintf (stderr, "  interfaces[%d] = %p (interface %s@%p : %s(%s))\n",
+		       index,
+		       klass->itable->addresses[index * 2],
+		       (const char*)cls->name->chars(),
+		       cls,
+		       (const char*)sym.name->chars(),
+		       (const char*)signature->chars());
+	      fprintf (stderr, "            [%d] = offset %d\n",
+		       index + 1,
+		       (int)(unsigned long)klass->itable->addresses[index * 2 + 1]);
+	    }
+
+	}
+      else
+	throw new java::lang::IncompatibleClassChangeError;
+    }
+
+}
+
+// For each catch_record in the list of caught classes, fill in the
+// address field.
+void 
+_Jv_Linker::link_exception_table (jclass self)
+{
+  struct _Jv_CatchClass *catch_record = self->catch_classes;
+  if (!catch_record || catch_record->classname)
+    return;  
+  catch_record++;
+  while (catch_record->classname)
+    {
+      try
+	{
+	  jclass target_class
+	    = _Jv_FindClass (catch_record->classname,  
+			     self->getClassLoaderInternal ());
+	  *catch_record->address = target_class;
+	}
+      catch (::java::lang::Throwable *t)
+	{
+	  // FIXME: We need to do something better here.
+	  *catch_record->address = 0;
+	}
+      catch_record++;
+    }
+  self->catch_classes->classname = (_Jv_Utf8Const *)-1;
+}
+  
+// Set itable method indexes for members of interface IFACE.
+void
+_Jv_Linker::layout_interface_methods (jclass iface)
+{
+  if (! iface->isInterface())
+    return;
+
+  // itable indexes start at 1. 
+  // FIXME: Static initalizers currently get a NULL placeholder entry in the
+  // itable so they are also assigned an index here.
+  for (int i = 0; i < iface->method_count; i++)
+    iface->methods[i].index = i + 1;
+}
+
+// Prepare virtual method declarations in KLASS, and any superclasses
+// as required, by determining their vtable index, setting
+// method->index, and finally setting the class's vtable_method_count.
+// Must be called with the lock for KLASS held.
+void
+_Jv_Linker::layout_vtable_methods (jclass klass)
+{
+  if (klass->vtable != NULL || klass->isInterface() 
+      || klass->vtable_method_count != -1)
+    return;
+
+  jclass superclass = klass->getSuperclass();
+
+  if (superclass != NULL && superclass->vtable_method_count == -1)
+    {
+      JvSynchronize sync (superclass);
+      layout_vtable_methods (superclass);
+    }
+
+  int index = (superclass == NULL ? 0 : superclass->vtable_method_count);
+
+  for (int i = 0; i < klass->method_count; ++i)
+    {
+      _Jv_Method *meth = &klass->methods[i];
+      _Jv_Method *super_meth = NULL;
+
+      if (! _Jv_isVirtualMethod (meth))
+	continue;
+
+      if (superclass != NULL)
+	{
+	  jclass declarer;
+	  super_meth = _Jv_LookupDeclaredMethod (superclass, meth->name,
+						 meth->signature, &declarer);
+	  // See if this method actually overrides the other method
+	  // we've found.
+	  if (super_meth)
+	    {
+	      if (! _Jv_isVirtualMethod (super_meth)
+		  || ! _Jv_CheckAccess (klass, declarer,
+					super_meth->accflags))
+		super_meth = NULL;
+	      else if ((super_meth->accflags
+			& java::lang::reflect::Modifier::FINAL) != 0)
+		{
+		  using namespace java::lang;
+		  StringBuffer *sb = new StringBuffer();
+		  sb->append(JvNewStringLatin1("method "));
+		  sb->append(_Jv_GetMethodString(klass, meth));
+		  sb->append(JvNewStringLatin1(" overrides final method "));
+		  sb->append(_Jv_GetMethodString(declarer, super_meth));
+		  throw new VerifyError(sb->toString());
+		}
+	      else if (declarer->loader != klass->loader)
+		{
+		  // JVMS 5.4.2.
+		  check_loading_constraints (meth, klass, declarer);
+		}
+	    }
+	}
+
+      if (super_meth)
+        meth->index = super_meth->index;
+      else
+	meth->index = index++;
+    }
+
+  klass->vtable_method_count = index;
+}
+
+// Set entries in VTABLE for virtual methods declared in KLASS.
+void
+_Jv_Linker::set_vtable_entries (jclass klass, _Jv_VTable *vtable)
+{
+  for (int i = klass->method_count - 1; i >= 0; i--)
+    {
+      using namespace java::lang::reflect;
+
+      _Jv_Method *meth = &klass->methods[i];
+      if (meth->index == (_Jv_ushort) -1)
+	continue;
+      if ((meth->accflags & Modifier::ABSTRACT))
+	// FIXME: it might be nice to have a libffi trampoline here,
+	// so we could pass in the method name and other information.
+	vtable->set_method(meth->index,
+			   (void *) &_Jv_ThrowAbstractMethodError);
+      else
+	vtable->set_method(meth->index, meth->ncode);
+    }
+}
+
+// Allocate and lay out the virtual method table for KLASS.  This will
+// also cause vtables to be generated for any non-abstract
+// superclasses, and virtual method layout to occur for any abstract
+// superclasses.  Must be called with monitor lock for KLASS held.
+void
+_Jv_Linker::make_vtable (jclass klass)
+{
+  using namespace java::lang::reflect;  
+
+  // If the vtable exists, or for interface classes, do nothing.  All
+  // other classes, including abstract classes, need a vtable.
+  if (klass->vtable != NULL || klass->isInterface())
+    return;
+
+  // Ensure all the `ncode' entries are set.
+  klass->engine->create_ncode(klass);
+
+  // Class must be laid out before we can create a vtable. 
+  if (klass->vtable_method_count == -1)
+    layout_vtable_methods (klass);
+
+  // Allocate the new vtable.
+  _Jv_VTable *vtable = _Jv_VTable::new_vtable (klass->vtable_method_count);
+  klass->vtable = vtable;
+
+  // Copy the vtable of the closest superclass.
+  jclass superclass = klass->superclass;
+  {
+    JvSynchronize sync (superclass);
+    make_vtable (superclass);
+  }
+  for (int i = 0; i < superclass->vtable_method_count; ++i)
+    vtable->set_method (i, superclass->vtable->get_method (i));
+
+  // Set the class pointer and GC descriptor.
+  vtable->clas = klass;
+  vtable->gc_descr = _Jv_BuildGCDescr (klass);
+
+  // For each virtual declared in klass, set new vtable entry or
+  // override an old one.
+  set_vtable_entries (klass, vtable);
+
+  // Note that we don't check for abstract methods here.  We used to,
+  // but there is a JVMS clarification that indicates that a check
+  // here would be too eager.  And, a simple test case confirms this.
+}
+
+// Lay out the class, allocating space for static fields and computing
+// offsets of instance fields.  The class lock must be held by the
+// caller.
+void
+_Jv_Linker::ensure_fields_laid_out (jclass klass)
+{  
+  if (klass->size_in_bytes != -1)
+    return;
+
+  // Compute the alignment for this type by searching through the
+  // superclasses and finding the maximum required alignment.  We
+  // could consider caching this in the Class.
+  int max_align = __alignof__ (java::lang::Object);
+  jclass super = klass->getSuperclass();
+  while (super != NULL)
+    {
+      // Ensure that our super has its super installed before
+      // recursing.
+      wait_for_state(super, JV_STATE_LOADING);
+      ensure_fields_laid_out(super);
+      int num = JvNumInstanceFields (super);
+      _Jv_Field *field = JvGetFirstInstanceField (super);
+      while (num > 0)
+	{
+	  int field_align = get_alignment_from_class (field->type);
+	  if (field_align > max_align)
+	    max_align = field_align;
+	  ++field;
+	  --num;
+	}
+      super = super->getSuperclass();
+    }
+
+  int instance_size;
+  // This is the size of the 'static' non-reference fields.
+  int non_reference_size = 0;
+  // This is the size of the 'static' reference fields.  We count
+  // these separately to make it simpler for the GC to scan them.
+  int reference_size = 0;
+
+  // Although java.lang.Object is never interpreted, an interface can
+  // have a null superclass.  Note that we have to lay out an
+  // interface because it might have static fields.
+  if (klass->superclass)
+    instance_size = klass->superclass->size();
+  else
+    instance_size = java::lang::Object::class$.size();
+
+  klass->engine->allocate_field_initializers (klass); 
+
+  for (int i = 0; i < klass->field_count; i++)
+    {
+      int field_size;
+      int field_align;
+
+      _Jv_Field *field = &klass->fields[i];
+
+      if (! field->isRef ())
+	{
+	  // It is safe to resolve the field here, since it's a
+	  // primitive class, which does not cause loading to happen.
+	  resolve_field (field, klass->loader);
+	  field_size = field->type->size ();
+	  field_align = get_alignment_from_class (field->type);
+	}
+      else 
+	{
+	  field_size = sizeof (jobject);
+	  field_align = __alignof__ (jobject);
+	}
+
+      field->bsize = field_size;
+
+      if ((field->flags & java::lang::reflect::Modifier::STATIC))
+	{
+	  if (field->u.addr == NULL)
+	    {
+	      // This computes an offset into a region we'll allocate
+	      // shortly, and then adds this offset to the start
+	      // address.
+	      if (field->isRef())
+		{
+		  reference_size = ROUND (reference_size, field_align);
+		  field->u.boffset = reference_size;
+		  reference_size += field_size;
+		}
+	      else
+		{
+		  non_reference_size = ROUND (non_reference_size, field_align);
+		  field->u.boffset = non_reference_size;
+		  non_reference_size += field_size;
+		}
+	    }
+	}
+      else
+	{
+	  instance_size      = ROUND (instance_size, field_align);
+	  field->u.boffset   = instance_size;
+	  instance_size     += field_size;
+	  if (field_align > max_align)
+	    max_align = field_align;
+	}
+    }
+
+  if (reference_size != 0 || non_reference_size != 0)
+    klass->engine->allocate_static_fields (klass, reference_size,
+					   non_reference_size);
+
+  // Set the instance size for the class.  Note that first we round it
+  // to the alignment required for this object; this keeps us in sync
+  // with our current ABI.
+  instance_size = ROUND (instance_size, max_align);
+  klass->size_in_bytes = instance_size;
+}
+
+// This takes the class to state JV_STATE_LINKED.  The class lock must
+// be held when calling this.
+void
+_Jv_Linker::ensure_class_linked (jclass klass)
+{
+  if (klass->state >= JV_STATE_LINKED)
+    return;
+
+  int state = klass->state;
+  try
+    {
+      // Short-circuit, so that mutually dependent classes are ok.
+      klass->state = JV_STATE_LINKED;
+
+      _Jv_Constants *pool = &klass->constants;
+
+      // Compiled classes require that their class constants be
+      // resolved here.  However, interpreted classes need their
+      // constants to be resolved lazily.  If we resolve an
+      // interpreted class' constants eagerly, we can end up with
+      // spurious IllegalAccessErrors when the constant pool contains
+      // a reference to a class we can't access.  This can validly
+      // occur in an obscure case involving the InnerClasses
+      // attribute.
+      if (! _Jv_IsInterpretedClass (klass))
+	{
+	  // Resolve class constants first, since other constant pool
+	  // entries may rely on these.
+	  for (int index = 1; index < pool->size; ++index)
+	    {
+	      if (pool->tags[index] == JV_CONSTANT_Class)
+                // Lazily resolve the entries.
+		resolve_pool_entry (klass, index, true);
+	    }
+	}
+
+      // Resolve the remaining constant pool entries.
+      for (int index = 1; index < pool->size; ++index)
+	{
+	  jbyte tags;
+	  _Jv_word data;
+
+	  tags = read_cpool_entry (&data, pool, index);
+	  if (tags == JV_CONSTANT_String)
+	    {
+	      data.o = _Jv_NewStringUtf8Const (data.utf8);
+	      tags |= JV_CONSTANT_ResolvedFlag;
+	      write_cpool_entry (data, tags, pool, index);
+	    }
+	}
+
+      if (klass->engine->need_resolve_string_fields())
+	{
+	  jfieldID f = JvGetFirstStaticField (klass);
+	  for (int n = JvNumStaticFields (klass); n > 0; --n)
+	    {
+	      int mod = f->getModifiers ();
+	      // If we have a static String field with a non-null initial
+	      // value, we know it points to a Utf8Const.
+
+              // Finds out whether we have to initialize a String without the
+              // need to resolve the field.
+              if ((f->isResolved()
+                   ? (f->type == &java::lang::String::class$)
+                   : _Jv_equalUtf8Classnames((_Jv_Utf8Const *) f->type,
+                                             java::lang::String::class$.name))
+		  && (mod & java::lang::reflect::Modifier::STATIC) != 0)
+		{
+		  jstring *strp = (jstring *) f->u.addr;
+		  if (*strp)
+		    *strp = _Jv_NewStringUtf8Const ((_Jv_Utf8Const *) *strp);
+		}
+	      f = f->getNextField ();
+	    }
+	}
+
+      klass->notifyAll ();
+
+      _Jv_PushClass (klass);
+    }
+  catch (java::lang::Throwable *t)
+    {
+      klass->state = state;
+      throw t;
+    }
+}
+
+// This ensures that symbolic superclass and superinterface references
+// are resolved for the indicated class.  This must be called with the
+// class lock held.
+void
+_Jv_Linker::ensure_supers_installed (jclass klass)
+{
+  resolve_class_ref (klass, &klass->superclass);
+  // An interface won't have a superclass.
+  if (klass->superclass)
+    wait_for_state (klass->superclass, JV_STATE_LOADING);
+
+  for (int i = 0; i < klass->interface_count; ++i)
+    {
+      resolve_class_ref (klass, &klass->interfaces[i]);
+      wait_for_state (klass->interfaces[i], JV_STATE_LOADING);
+    }
+}
+
+// This adds missing `Miranda methods' to a class.
+void
+_Jv_Linker::add_miranda_methods (jclass base, jclass iface_class)
+{
+  // Note that at this point, all our supers, and the supers of all
+  // our superclasses and superinterfaces, will have been installed.
+
+  for (int i = 0; i < iface_class->interface_count; ++i)
+    {
+      jclass interface = iface_class->interfaces[i];
+
+      for (int j = 0; j < interface->method_count; ++j)
+	{
+ 	  _Jv_Method *meth = &interface->methods[j];
+	  // Don't bother with <clinit>.
+	  if (meth->name->first() == '<')
+	    continue;
+	  _Jv_Method *new_meth = _Jv_LookupDeclaredMethod (base, meth->name,
+							   meth->signature);
+	  if (! new_meth)
+	    {
+	      // We assume that such methods are very unlikely, so we
+	      // just reallocate the method array each time one is
+	      // found.  This greatly simplifies the searching --
+	      // otherwise we have to make sure that each such method
+	      // found is really unique among all superinterfaces.
+	      int new_count = base->method_count + 1;
+	      _Jv_Method *new_m
+		= (_Jv_Method *) _Jv_AllocRawObj (sizeof (_Jv_Method)
+						  * new_count);
+	      memcpy (new_m, base->methods,
+		      sizeof (_Jv_Method) * base->method_count);
+
+	      // Add new method.
+	      new_m[base->method_count] = *meth;
+	      new_m[base->method_count].index = (_Jv_ushort) -1;
+	      new_m[base->method_count].accflags
+		|= java::lang::reflect::Modifier::INVISIBLE;
+
+	      base->methods = new_m;
+	      base->method_count = new_count;
+	    }
+	}
+
+      wait_for_state (interface, JV_STATE_LOADED);
+      add_miranda_methods (base, interface);
+    }
+}
+
+// This ensures that the class' method table is "complete".  This must
+// be called with the class lock held.
+void
+_Jv_Linker::ensure_method_table_complete (jclass klass)
+{
+  if (klass->vtable != NULL)
+    return;
+
+  // We need our superclass to have its own Miranda methods installed.
+  if (! klass->isInterface())
+    wait_for_state (klass->getSuperclass (), JV_STATE_LOADED);
+
+  // A class might have so-called "Miranda methods".  This is a method
+  // that is declared in an interface and not re-declared in an
+  // abstract class.  Some compilers don't emit declarations for such
+  // methods in the class; this will give us problems since we expect
+  // a declaration for any method requiring a vtable entry.  We handle
+  // this here by searching for such methods and constructing new
+  // internal declarations for them.  Note that we do this
+  // unconditionally, and not just for abstract classes, to correctly
+  // account for cases where a class is modified to be concrete and
+  // still incorrectly inherits an abstract method.
+  int pre_count = klass->method_count;
+  add_miranda_methods (klass, klass);
+
+  // Let the execution engine know that we've added methods.
+  if (klass->method_count != pre_count)
+    klass->engine->post_miranda_hook(klass);
+}
+
+// Verify a class.  Must be called with class lock held.
+void
+_Jv_Linker::verify_class (jclass klass)
+{
+  klass->engine->verify(klass);
+}
+
+// Check the assertions contained in the type assertion table for KLASS.
+// This is the equivilent of bytecode verification for native, BC-ABI code.
+void
+_Jv_Linker::verify_type_assertions (jclass klass)
+{
+  if (debug_link)
+    fprintf (stderr, "Evaluating type assertions for %s:\n",
+	     klass->name->chars());
+
+  if (klass->assertion_table == NULL)
+    return;
+
+  for (int i = 0;; i++)
+    {
+      int assertion_code = klass->assertion_table[i].assertion_code;
+      _Jv_Utf8Const *op1 = klass->assertion_table[i].op1;
+      _Jv_Utf8Const *op2 = klass->assertion_table[i].op2;
+      
+      if (assertion_code == JV_ASSERT_END_OF_TABLE)
+        return;
+      else if (assertion_code == JV_ASSERT_TYPES_COMPATIBLE)
+        {
+	  if (debug_link)
+	    {
+	      fprintf (stderr, "  code=%i, operand A=%s B=%s\n",
+		       assertion_code, op1->chars(), op2->chars());
+	    }
+	
+	  // The operands are class signatures. op1 is the source, 
+	  // op2 is the target.
+	  jclass cl1 = _Jv_FindClassFromSignature (op1->chars(), 
+	    klass->getClassLoaderInternal());
+	  jclass cl2 = _Jv_FindClassFromSignature (op2->chars(),
+	    klass->getClassLoaderInternal());
+	    
+	  // If the class doesn't exist, ignore the assertion. An exception
+	  // will be thrown later if an attempt is made to actually 
+	  // instantiate the class.
+	  if (cl1 == NULL || cl2 == NULL)
+	    continue;
+
+          if (! _Jv_IsAssignableFromSlow (cl1, cl2))
+	    {
+	      jstring s = JvNewStringUTF ("Incompatible types: In class ");
+	      s = s->concat (klass->getName());
+	      s = s->concat (JvNewStringUTF (": "));
+	      s = s->concat (cl1->getName());
+	      s = s->concat (JvNewStringUTF (" is not assignable to "));
+	      s = s->concat (cl2->getName());
+	      throw new java::lang::VerifyError (s);
+	    }
+	}
+      else if (assertion_code == JV_ASSERT_IS_INSTANTIABLE)
+        {
+	  // TODO: Implement this.
+	}
+      // Unknown assertion codes are ignored, for forwards-compatibility.
+    }
+}
+   
+void
+_Jv_Linker::print_class_loaded (jclass klass)
+{
+  char *codesource = NULL;
+  if (klass->protectionDomain != NULL)
+    {
+      java::security::CodeSource *cs
+	= klass->protectionDomain->getCodeSource();
+      if (cs != NULL)
+	{
+	  jstring css = cs->toString();
+	  int len = JvGetStringUTFLength(css);
+	  codesource = (char *) _Jv_AllocBytes(len + 1);
+	  JvGetStringUTFRegion(css, 0, css->length(), codesource);
+	  codesource[len] = '\0';
+	}
+    }
+  if (codesource == NULL)
+    codesource = (char *) "<no code source>";
+
+  const char *abi;
+  if (_Jv_IsInterpretedClass (klass))
+    abi = "bytecode";
+  else if (_Jv_IsBinaryCompatibilityABI (klass))
+    abi = "BC-compiled";
+  else
+    abi = "pre-compiled";
+
+  fprintf (stderr, "[Loaded (%s) %s from %s]\n", abi, klass->name->chars(),
+	   codesource);
+}
+
+// FIXME: mention invariants and stuff.
+void
+_Jv_Linker::wait_for_state (jclass klass, int state)
+{
+  if (klass->state >= state)
+    return;
+
+  java::lang::Thread *self = java::lang::Thread::currentThread();
+
+  {
+    JvSynchronize sync (klass);
+
+    // This is similar to the strategy for class initialization.  If we
+    // already hold the lock, just leave.
+    while (klass->state <= state
+	   && klass->thread 
+	   && klass->thread != self)
+      klass->wait ();
+
+    java::lang::Thread *save = klass->thread;
+    klass->thread = self;
+
+    // Allocate memory for static fields and constants.
+    if (GC_base (klass) && klass->fields && ! GC_base (klass->fields))
+      {
+	jsize count = klass->field_count;
+	if (count)
+	  {
+	    _Jv_Field* fields 
+	      = (_Jv_Field*) _Jv_AllocRawObj (count * sizeof (_Jv_Field));
+	    memcpy ((void*)fields,
+		    (void*)klass->fields,
+		    count * sizeof (_Jv_Field));
+	    klass->fields = fields;
+	  }
+      }
+      
+  // Print some debugging info if requested.  Interpreted classes are
+  // handled in defineclass, so we only need to handle the two
+  // pre-compiled cases here.
+  if ((klass->state == JV_STATE_COMPILED
+	  || klass->state == JV_STATE_PRELOADING)
+      && ! _Jv_IsInterpretedClass (klass))
+    {
+      if (gcj::verbose_class_flag)
+	print_class_loaded (klass);
+      ++gcj::loadedClasses;
+    }
+
+    try
+      {
+	if (state >= JV_STATE_LOADING && klass->state < JV_STATE_LOADING)
+	  {
+	    ensure_supers_installed (klass);
+	    klass->set_state(JV_STATE_LOADING);
+	  }
+
+	if (state >= JV_STATE_LOADED && klass->state < JV_STATE_LOADED)
+	  {
+	    ensure_method_table_complete (klass);
+	    klass->set_state(JV_STATE_LOADED);
+	  }
+
+	if (state >= JV_STATE_PREPARED && klass->state < JV_STATE_PREPARED)
+	  {
+	    ensure_fields_laid_out (klass);
+	    make_vtable (klass);
+	    layout_interface_methods (klass);
+	    prepare_constant_time_tables (klass);
+	    klass->set_state(JV_STATE_PREPARED);
+	  }
+
+	if (state >= JV_STATE_LINKED && klass->state < JV_STATE_LINKED)
+	  {
+	    if (gcj::verifyClasses)
+	      verify_class (klass);
+
+	    ensure_class_linked (klass);
+	    link_exception_table (klass);
+	    link_symbol_table (klass);
+	    klass->set_state(JV_STATE_LINKED);
+	  }
+      }
+    catch (java::lang::Throwable *exc)
+      {
+	klass->thread = save;
+	klass->set_state(JV_STATE_ERROR);
+	throw exc;
+      }
+
+    klass->thread = save;
+
+    if (klass->state == JV_STATE_ERROR)
+      throw new java::lang::LinkageError;
+  }
+
+#ifdef INTERPRETER
+  if (__builtin_expect (klass->state == JV_STATE_LINKED, false)
+      && state >= JV_STATE_LINKED
+      && JVMTI_REQUESTED_EVENT (ClassPrepare))
+    {
+      JNIEnv *jni_env = _Jv_GetCurrentJNIEnv ();
+      _Jv_JVMTI_PostEvent (JVMTI_EVENT_CLASS_PREPARE, self, jni_env,
+			   klass);
+    }
+#endif
+}