obtained gcc-4.6.4.tar.bz2 from upstream website;upstream

verified gcc-4.6.4.tar.bz2.sig;
imported gcc-4.6.4 source tree from verified upstream tarball.

downloading a git-generated archive based on the 'upstream' tag
should provide you with a source tree that is binary identical
to the one extracted from the above tarball.

if you have obtained the source via the command 'git clone',
however, do note that line-endings of files in your working
directory might differ from line-endings of the respective
files in the upstream repository.

1 files changed, 828 insertions, 0 deletions

diff --git a/libjava/stacktrace.cc b/libjava/stacktrace.cc
new file mode 100644
index 000000000..d8d1f38ae
--- /dev/null
+++ b/libjava/stacktrace.cc
@@ -0,0 +1,828 @@
+// stacktrace.cc - Functions for unwinding & inspecting the call stack.
+
+/* Copyright (C) 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.  */
+
+#include <config.h>
+#include <platform.h>
+
+#include <jvm.h>
+#include <gcj/cni.h>
+#include <java-interp.h>
+#include <java-stack.h>
+
+#include <stdio.h>
+
+#include <java/lang/Boolean.h>
+#include <java/lang/Class.h>
+#include <java/lang/Long.h>
+#include <java/lang/reflect/Method.h>
+#include <java/security/AccessController.h>
+#include <java/util/ArrayList.h>
+#include <java/util/IdentityHashMap.h>
+#include <gnu/classpath/jdwp/Jdwp.h>
+#include <gnu/classpath/VMStackWalker.h>
+#include <gnu/java/lang/MainThread.h>
+#include <gnu/gcj/runtime/NameFinder.h>
+#include <gnu/gcj/runtime/StringBuffer.h>
+
+#include <sysdep/backtrace.h>
+#include <sysdep/descriptor.h>
+
+using namespace java::lang;
+using namespace java::lang::reflect;
+using namespace java::util;
+using namespace gnu::gcj::runtime;
+
+#ifdef __ARM_EABI_UNWINDER__
+#define _URC_NORMAL_STOP _URC_FAILURE
+#endif
+
+// Maps ncode values to their containing native class.
+// NOTE: Currently this Map contradicts class GC for native classes. This map
+// (and the "new class stack") will need to use WeakReferences in order to 
+// enable native class GC.
+java::util::IdentityHashMap *_Jv_StackTrace::ncodeMap;
+
+// Check the "class stack" for any classes initialized since we were last 
+// called, and add them to ncodeMap.
+void 
+_Jv_StackTrace::UpdateNCodeMap ()
+{
+  // The Map should be large enough so that a typical Java app doesn't cause 
+  // it to rehash, without using too much memory. ~5000 entries should be 
+  // enough.
+  if (ncodeMap == NULL)
+    ncodeMap = new java::util::IdentityHashMap (5087);
+  
+  jclass klass;
+  while ((klass = _Jv_PopClass ()))
+    {
+      //printf ("got %s\n", klass->name->data);
+      for (int i = 0; i < klass->method_count; i++)
+	{
+	  _Jv_Method *method = &klass->methods[i];
+	  void *ncode = method->ncode;
+	  // Add non-abstract methods to ncodeMap.
+	  if (ncode)
+	    {
+	      ncode = UNWRAP_FUNCTION_DESCRIPTOR (ncode);
+	      ncodeMap->put ((java::lang::Object *) ncode, klass);
+	    }
+	}
+    }
+}
+
+// Given a native frame, return the class which this code belongs 
+// to. Returns NULL if this IP is not associated with a native Java class.
+// If NCODE is supplied, it will be set with the ip for the entry point of the 
+// enclosing method.
+jclass
+_Jv_StackTrace::ClassForFrame (_Jv_StackFrame *frame)
+{
+  JvAssert (frame->type == frame_native);
+  jclass klass = NULL;
+
+  // look it up in ncodeMap
+  if (frame->start_ip)
+    {
+      klass = (jclass) ncodeMap->get ((jobject) frame->start_ip);
+
+      // Exclude interpreted classes
+      if (klass != NULL && _Jv_IsInterpretedClass (klass))
+	klass = NULL;
+    }
+
+  return klass;
+}
+
+_Unwind_Reason_Code
+_Jv_StackTrace::UnwindTraceFn (struct _Unwind_Context *context, void *state_ptr)
+{
+  _Jv_UnwindState *state = (_Jv_UnwindState *) state_ptr;
+  jint pos = state->pos;
+
+  // Check if the trace buffer needs to be extended.
+  if (pos == state->length)
+    {
+      int newLength = state->length * 2;
+      void *newFrames = _Jv_AllocBytes (newLength * sizeof(_Jv_StackFrame));
+      memcpy (newFrames, state->frames, state->length * sizeof(_Jv_StackFrame));      
+      state->frames = (_Jv_StackFrame *) newFrames;
+      state->length = newLength;
+    }
+
+  void *func_addr = (void *) _Unwind_GetRegionStart (context);
+
+  // If we see the interpreter's main function, "pop" an entry off the 
+  // interpreter stack and use that instead, so that the trace goes through 
+  // the java code and not the interpreter itself. This assumes a 1:1 
+  // correspondance between call frames in the interpreted stack and occurances
+  // of _Jv_InterpMethod::run() on the native stack.
+#ifdef INTERPRETER
+  void *interp_run = NULL;
+  
+  if (::gnu::classpath::jdwp::Jdwp::isDebugging)
+  	interp_run = (void *) &_Jv_InterpMethod::run_debug;
+  else
+    interp_run = (void *) &_Jv_InterpMethod::run;
+  	
+  if (func_addr == UNWRAP_FUNCTION_DESCRIPTOR (interp_run))
+    {
+      state->frames[pos].type = frame_interpreter;
+      _Jv_Frame *frame = static_cast<_Jv_Frame *> (state->interp_frame);
+      state->frames[pos].interp.meth 
+        = static_cast<_Jv_InterpMethod *> (frame->self);
+      state->frames[pos].interp.pc = state->interp_frame->pc;
+      state->interp_frame = state->interp_frame->next_interp;
+    }
+  else 
+  // We handle proxies in the same way as interpreted classes
+  if (_Jv_is_proxy (func_addr))
+    {
+      state->frames[pos].type = frame_proxy;
+      state->frames[pos].proxyClass = state->interp_frame->proxyClass;
+      state->frames[pos].proxyMethod = state->interp_frame->proxyMethod;
+      state->interp_frame = state->interp_frame->next_interp;
+    }
+  else 
+#endif
+    {
+#ifdef HAVE_GETIPINFO
+      _Unwind_Ptr ip;
+      int ip_before_insn = 0;
+      ip = _Unwind_GetIPInfo (context, &ip_before_insn);
+
+      // If the unwinder gave us a 'return' address, roll it back a little
+      // to ensure we get the correct line number for the call itself.
+      if (! ip_before_insn)
+	--ip;
+#endif
+      state->frames[pos].type = frame_native;
+#ifdef HAVE_GETIPINFO
+      state->frames[pos].ip = (void *) ip;
+#else
+      state->frames[pos].ip = (void *) _Unwind_GetIP (context);
+#endif
+      state->frames[pos].start_ip = func_addr;
+    }
+
+  _Unwind_Reason_Code result = _URC_NO_REASON;
+  if (state->trace_function != NULL)
+    result = (state->trace_function) (state);
+  state->pos++;
+  return result;
+}
+
+// Return a raw stack trace from the current point of execution. The raw 
+// trace will include all functions that have unwind info.
+_Jv_StackTrace *
+_Jv_StackTrace::GetStackTrace(void)
+{
+  int trace_size = 100;
+  _Jv_StackFrame frames[trace_size];
+  _Jv_UnwindState state (trace_size);
+  state.frames = (_Jv_StackFrame *) &frames;
+
+  _Unwind_Backtrace (UnwindTraceFn, &state);
+  
+  // Copy the trace and return it.
+  int traceSize = sizeof (_Jv_StackTrace) + 
+    (sizeof (_Jv_StackFrame) * state.pos);
+  _Jv_StackTrace *trace = (_Jv_StackTrace *) _Jv_AllocBytes (traceSize);
+  trace->length = state.pos;
+  memcpy (trace->frames, state.frames, sizeof (_Jv_StackFrame) * state.pos);  
+  return trace;
+}
+
+void
+_Jv_StackTrace::getLineNumberForFrame(_Jv_StackFrame *frame, NameFinder *finder, 
+				      jstring *sourceFileName, jint *lineNum,
+				      jstring *methodName)
+{
+#ifdef INTERPRETER
+  if (frame->type == frame_interpreter)
+    {
+      _Jv_InterpMethod *interp_meth = frame->interp.meth;
+      _Jv_InterpClass *interp_class = 
+	 (_Jv_InterpClass *) interp_meth->defining_class->aux_info;
+      *sourceFileName = interp_class->source_file_name;
+      // The interpreter advances the PC before executing an instruction,
+      // so roll-back 1 byte to ensure the line number is accurate.
+      *lineNum = interp_meth->get_source_line(frame->interp.pc - 1);
+      return;
+    }
+#endif
+
+  if (frame->type == frame_proxy)
+    {
+      *sourceFileName = NULL;
+      *lineNum = 0;
+      return;
+    }
+
+  // Use _Jv_platform_dladdr() to determine in which binary the address IP
+  // resides.
+  _Jv_AddrInfo info;
+  jstring binaryName = NULL;
+  const char *argv0 = _Jv_GetSafeArg(0);
+
+  void *ip = frame->ip;
+  _Unwind_Ptr offset = 0;
+
+  if (_Jv_platform_dladdr (ip, &info))
+    {
+      if (info.file_name)
+	binaryName = JvNewStringUTF (info.file_name);
+      else
+        return;
+
+      if (*methodName == NULL && info.sym_name)
+	*methodName = JvNewStringUTF (info.sym_name);
+
+      // addr2line expects relative addresses for shared libraries.
+      if (strcmp (info.file_name, argv0) == 0)
+        offset = (_Unwind_Ptr) ip;
+      else
+        offset = (_Unwind_Ptr) ip - (_Unwind_Ptr) info.base;
+
+#ifndef HAVE_GETIPINFO
+      // The unwinder gives us the return address. In order to get the right
+      // line number for the stack trace, roll it back a little.
+      offset -= 1;
+#endif
+
+      finder->lookup (binaryName, (jlong) offset);
+      *sourceFileName = finder->getSourceFile();
+      *lineNum = finder->getLineNum();
+      if (*lineNum == -1 && NameFinder::showRaw())
+        {
+          gnu::gcj::runtime::StringBuffer *t =
+            new gnu::gcj::runtime::StringBuffer(binaryName);
+          t->append ((jchar)' ');
+          t->append ((jchar)'[');
+          // + 1 to compensate for the - 1 adjustment above;
+          t->append (Long::toHexString (offset + 1));
+          t->append ((jchar)']');
+          *sourceFileName = t->toString();
+        }
+    }
+}
+
+// Look up class and method info for the given stack frame, setting 
+// frame->klass and frame->meth if they are known.
+void
+_Jv_StackTrace::FillInFrameInfo (_Jv_StackFrame *frame)
+{
+  jclass klass = NULL;
+  _Jv_Method *meth = NULL;
+  
+  if (frame->type == frame_native)
+    {
+      klass = _Jv_StackTrace::ClassForFrame (frame);
+
+      if (klass != NULL)
+	// Find method in class
+	for (int j = 0; j < klass->method_count; j++)
+	  {
+	    void *wncode = UNWRAP_FUNCTION_DESCRIPTOR (klass->methods[j].ncode);
+	    if (wncode == frame->start_ip)
+	      {
+		meth = &klass->methods[j];
+		break;
+	      }
+	  }
+    }
+  else if (frame->type == frame_proxy)
+    {
+      klass = frame->proxyClass;
+      meth = frame->proxyMethod;
+    }
+#ifdef INTERPRETER
+  else if (frame->type == frame_interpreter)
+    {
+      _Jv_InterpMethod *interp_meth = frame->interp.meth;
+      klass = interp_meth->defining_class;
+      meth = interp_meth->self;
+    }
+#endif
+  else
+    JvFail ("Unknown frame type");
+  
+  frame->klass = klass;
+  frame->meth = meth;
+}
+
+// Convert raw stack frames to a Java array of StackTraceElement objects.
+JArray< ::java::lang::StackTraceElement *>*
+_Jv_StackTrace::GetStackTraceElements (_Jv_StackTrace *trace, 
+  Throwable *throwable __attribute__((unused)))
+{
+  ArrayList *list = new ArrayList ();
+
+#if defined (SJLJ_EXCEPTIONS) && ! defined (WIN32)
+  // We can't use the nCodeMap without unwinder support. Instead,
+  // fake the method name by giving the IP in hex - better than nothing.  
+  jstring hex = JvNewStringUTF ("0x");
+
+  for (int i = 0; i < trace->length; i++)
+    {
+      jstring sourceFileName = NULL;
+      jint lineNum = -1;
+      _Jv_StackFrame *frame = &trace->frames[i];
+      
+      jstring className = NULL;
+      jstring methodName = hex->concat (Long::toHexString ((jlong) frame->ip));
+
+      StackTraceElement *element = new StackTraceElement (sourceFileName, 
+	lineNum, className, methodName, 0);    
+      list->add (element);
+    }
+
+#else /* SJLJ_EXCEPTIONS && !WIN32 */
+
+  //JvSynchronized (ncodeMap);
+  UpdateNCodeMap ();
+
+  NameFinder *finder = new NameFinder();
+  int start_idx = 0;
+  int end_idx = trace->length - 1;
+
+  // First pass: strip superfluous frames from beginning and end of the trace.  
+  for (int i = 0; i < trace->length; i++)
+    {
+      _Jv_StackFrame *frame = &trace->frames[i];
+      FillInFrameInfo (frame);
+
+      if (!frame->klass || !frame->meth)
+        // Not a Java frame.
+        continue;
+
+      // Throw away the top of the stack till we see:
+      //  - the constructor(s) of this Throwable, or
+      //  - the Throwable.fillInStackTrace call.
+      if (frame->klass == throwable->getClass()
+          && strcmp (frame->meth->name->chars(), "<init>") == 0)
+        start_idx = i + 1;
+
+      if (frame->klass == &Throwable::class$
+          && strcmp (frame->meth->name->chars(), "fillInStackTrace") == 0)
+	start_idx = i + 1;
+
+      // End the trace at the application's main() method if we see call_main.
+      if (frame->klass == &gnu::java::lang::MainThread::class$
+          && strcmp (frame->meth->name->chars(), "call_main") == 0)
+	end_idx = i - 1;
+    }
+  
+  const jboolean remove_unknown 
+    = gnu::gcj::runtime::NameFinder::removeUnknown();
+
+  // Second pass: Look up line-number info for remaining frames.
+  for (int i = start_idx; i <= end_idx; i++)
+    {
+      _Jv_StackFrame *frame = &trace->frames[i];
+      
+      if (frame->klass == NULL && remove_unknown)
+	// Not a Java frame.
+	continue;
+
+      jstring className = NULL;
+      if (frame->klass != NULL)
+	className = frame->klass->getName ();
+
+      jstring methodName = NULL;
+      if (frame->meth)
+        methodName = JvNewStringUTF (frame->meth->name->chars());
+      
+      jstring sourceFileName = NULL;
+      jint lineNum = -1;
+      
+      getLineNumberForFrame(frame, finder, &sourceFileName, &lineNum, 
+			    &methodName);
+      
+      StackTraceElement *element = new StackTraceElement (sourceFileName, lineNum,
+        className, methodName, 0);
+      list->add (element);
+    }
+  
+  finder->close();
+#endif /* SJLJ_EXCEPTIONS && !WIN32 */
+
+  JArray<Object *> *array = JvNewObjectArray (list->size (), 
+    &StackTraceElement::class$, NULL);
+
+  return (JArray<StackTraceElement *>*) list->toArray (array);
+}
+
+struct CallingClassTraceData
+{
+  jclass checkClass;    
+  jclass foundClass;
+  _Jv_Method *foundMeth;
+  bool seen_checkClass;
+};
+
+_Unwind_Reason_Code
+_Jv_StackTrace::calling_class_trace_fn (_Jv_UnwindState *state)
+{
+  CallingClassTraceData *trace_data = (CallingClassTraceData *)
+    state->trace_data;
+  _Jv_StackFrame *frame = &state->frames[state->pos];
+  FillInFrameInfo (frame);
+
+  if (trace_data->seen_checkClass
+      && frame->klass
+      && frame->klass != trace_data->checkClass)
+    {
+      trace_data->foundClass = frame->klass;
+      trace_data->foundMeth = frame->meth;
+      return _URC_NORMAL_STOP;
+    }
+  
+  if (frame->klass == trace_data->checkClass)
+    trace_data->seen_checkClass = true;
+    
+  return _URC_NO_REASON;
+}
+
+// Find the class immediately above the given class on the call stack. Any 
+// intermediate non-Java 
+// frames are ignored. If the calling class could not be determined (eg because 
+// the unwinder is not supported on this platform), NULL is returned.
+// This function is used to implement calling-classloader checks and reflection
+// accessibility checks.
+// CHECKCLASS is typically the class calling GetCallingClass. The first class
+// above CHECKCLASS on the call stack will be returned.
+jclass
+_Jv_StackTrace::GetCallingClass (jclass checkClass)
+{
+  jclass result = NULL;
+  GetCallerInfo (checkClass, &result, NULL);
+  return result;
+}
+
+void
+_Jv_StackTrace::GetCallerInfo (jclass checkClass, jclass *caller_class,
+  _Jv_Method **caller_meth)
+{
+  int trace_size = 20;
+  _Jv_StackFrame frames[trace_size];
+  _Jv_UnwindState state (trace_size);
+  state.frames = (_Jv_StackFrame *) &frames;
+
+  CallingClassTraceData trace_data;
+  trace_data.checkClass = checkClass;
+  trace_data.seen_checkClass = false;
+  trace_data.foundClass = NULL;
+  trace_data.foundMeth = NULL;
+
+  state.trace_function = calling_class_trace_fn;
+  state.trace_data = (void *) &trace_data;
+
+  //JvSynchronized (ncodeMap);
+  UpdateNCodeMap ();
+
+  _Unwind_Backtrace (UnwindTraceFn, &state);
+  
+  if (caller_class)
+    *caller_class = trace_data.foundClass;
+  if (caller_meth)
+    *caller_meth = trace_data.foundMeth;
+}
+
+_Unwind_Reason_Code
+_Jv_StackTrace::non_system_trace_fn (_Jv_UnwindState *state)
+{
+  _Jv_StackFrame *frame = &state->frames[state->pos];
+  FillInFrameInfo (frame);
+  
+  ClassLoader *classLoader = NULL;
+
+  if (frame->klass)
+    {
+      classLoader = frame->klass->getClassLoaderInternal();
+#ifdef INTERPRETER
+      if (classLoader != NULL)
+        {
+          state->trace_data = (void *) classLoader;
+	  return _URC_NORMAL_STOP;
+	}
+#endif
+    }
+
+  return _URC_NO_REASON;
+}
+
+ClassLoader *
+_Jv_StackTrace::GetFirstNonSystemClassLoader ()
+{
+  int trace_size = 32;
+  _Jv_StackFrame frames[trace_size];
+  _Jv_UnwindState state (trace_size);
+  state.frames = (_Jv_StackFrame *) &frames;
+  state.trace_function = non_system_trace_fn;
+  state.trace_data = NULL;
+
+  //JvSynchronized (ncodeMap);
+  UpdateNCodeMap ();
+  
+  _Unwind_Backtrace (UnwindTraceFn, &state);
+
+  if (state.trace_data)
+    return (ClassLoader *) state.trace_data;
+  
+  return NULL;
+}
+
+struct AccessControlTraceData
+{
+  jint length;
+  jboolean privileged;
+};
+
+_Unwind_Reason_Code
+_Jv_StackTrace::accesscontrol_trace_fn (_Jv_UnwindState *state)
+{
+  AccessControlTraceData *trace_data = (AccessControlTraceData *)
+    state->trace_data;
+  _Jv_StackFrame *frame = &state->frames[state->pos];
+  FillInFrameInfo (frame);
+
+  if (!(frame->klass && frame->meth))
+    return _URC_NO_REASON;
+
+  trace_data->length++;
+
+  // If the previous frame was a call to doPrivileged, then this is
+  // the last frame we look at.
+  if (trace_data->privileged)
+    return _URC_NORMAL_STOP;
+  
+  if (frame->klass == &::java::security::AccessController::class$
+      && strcmp (frame->meth->name->chars(), "doPrivileged") == 0)
+    trace_data->privileged = true;
+
+  return _URC_NO_REASON;
+}
+
+jobjectArray
+_Jv_StackTrace::GetAccessControlStack (void)
+{
+  int trace_size = 100;
+  _Jv_StackFrame frames[trace_size];
+  _Jv_UnwindState state (trace_size);
+  state.frames = (_Jv_StackFrame *) &frames;
+
+  AccessControlTraceData trace_data;
+  trace_data.length = 0;
+  trace_data.privileged = false;
+  
+  state.trace_function = accesscontrol_trace_fn;
+  state.trace_data = (void *) &trace_data;
+
+  UpdateNCodeMap();
+  _Unwind_Backtrace (UnwindTraceFn, &state);
+
+  JArray<jclass> *classes = (JArray<jclass> *)
+    _Jv_NewObjectArray (trace_data.length, &::java::lang::Class::class$, NULL);
+  jclass *c = elements (classes);
+
+  for (int i = 0, j = 0; i < state.pos; i++)
+    {
+      _Jv_StackFrame *frame = &state.frames[i];
+      if (!frame->klass || !frame->meth)
+	continue;
+      c[j] = frame->klass;
+      j++;
+    }
+
+  jobjectArray result =
+    (jobjectArray) _Jv_NewObjectArray (2, &::java::lang::Object::class$,
+					 NULL);
+  jobject *r = elements (result);
+  r[0] = (jobject) classes;
+  r[1] = (jobject) new Boolean (trace_data.privileged);
+  
+  return result;
+}
+
+JArray<jclass> *
+_Jv_StackTrace::GetStackWalkerStack ()
+{
+  int trace_size = 100;
+  _Jv_StackFrame frames[trace_size];
+  _Jv_UnwindState state (trace_size);
+  state.frames = (_Jv_StackFrame *) &frames;
+
+  UpdateNCodeMap ();
+  _Unwind_Backtrace (UnwindTraceFn, &state);
+
+  int num_frames = 0, start_frame = -1;
+  enum
+    {
+      VMSW_GETCLASSCONTEXT,
+      JLRM_INVOKE_OR_USER_FN,
+      USER_FN
+    }
+  expect = VMSW_GETCLASSCONTEXT;
+  for (int i = 0; i < state.pos; i++)
+    {
+      _Jv_StackFrame *frame = &state.frames[i];
+      FillInFrameInfo (frame);
+      if (!frame->klass || !frame->meth)
+	continue;
+
+      switch (expect)
+	{
+	case VMSW_GETCLASSCONTEXT:
+	  JvAssert (
+	    frame->klass == &::gnu::classpath::VMStackWalker::class$
+	    && strcmp (frame->meth->name->chars(), "getClassContext") == 0);
+	  expect = JLRM_INVOKE_OR_USER_FN;
+	  break;
+
+	case JLRM_INVOKE_OR_USER_FN:
+	  if (frame->klass != &::java::lang::reflect::Method::class$
+	      || strcmp (frame->meth->name->chars(), "invoke") != 0)
+	    start_frame = i;
+	  expect = USER_FN;
+	  break;
+
+	case USER_FN:
+	  if (start_frame == -1)
+	    start_frame = i;
+	  break;
+	}
+
+      if (start_frame != -1)
+	{
+	  if (frame->klass == &::gnu::java::lang::MainThread::class$)
+	    break;
+	  num_frames++;
+	}
+    }
+  JvAssert (num_frames > 0 && start_frame > 0);
+
+  JArray<jclass> *result = (JArray<jclass> *)
+    _Jv_NewObjectArray (num_frames, &::java::lang::Class::class$, NULL);
+  jclass *c = elements (result);
+
+  for (int i = start_frame, j = 0; i < state.pos && j < num_frames; i++)
+    {
+      _Jv_StackFrame *frame = &state.frames[i];
+      if (!frame->klass || !frame->meth)
+	continue;
+      c[j] = frame->klass;
+      j++;
+    }
+ 
+  return result;
+}
+
+typedef enum
+  {
+    VMSW_GET_CALLING_ITEM,
+    JLRM_INVOKE_OR_CALLER,
+    CALLER,
+    CALLER_OF_CALLER
+  } gswcc_expect;
+
+struct StackWalkerTraceData
+{
+  gswcc_expect expect;
+  jclass result;
+};
+
+_Unwind_Reason_Code
+_Jv_StackTrace::stackwalker_trace_fn (_Jv_UnwindState *state)
+{
+  StackWalkerTraceData *trace_data = (StackWalkerTraceData *)
+    state->trace_data;
+  _Jv_StackFrame *frame = &state->frames[state->pos];
+  FillInFrameInfo (frame);
+
+  if (!(frame->klass && frame->meth))
+    return _URC_NO_REASON;
+
+  switch (trace_data->expect)
+    {
+    case VMSW_GET_CALLING_ITEM:
+      JvAssert (frame->klass == &::gnu::classpath::VMStackWalker::class$);
+      trace_data->expect = JLRM_INVOKE_OR_CALLER;
+      break;
+
+    case JLRM_INVOKE_OR_CALLER:
+      if (frame->klass == &::java::lang::reflect::Method::class$
+	  && strcmp (frame->meth->name->chars(), "invoke") == 0)
+	trace_data->expect = CALLER;
+      else
+	trace_data->expect = CALLER_OF_CALLER;
+      break;
+
+    case CALLER:
+      trace_data->expect = CALLER_OF_CALLER;
+      break;
+
+    case CALLER_OF_CALLER:
+      trace_data->result = frame->klass;
+      return _URC_NORMAL_STOP;
+    }
+
+  return _URC_NO_REASON;
+}
+
+jclass
+_Jv_StackTrace::GetStackWalkerCallingClass (void)
+{
+  int trace_size = 100;
+  _Jv_StackFrame frames[trace_size];
+  _Jv_UnwindState state (trace_size);
+  state.frames = (_Jv_StackFrame *) &frames;
+
+  StackWalkerTraceData trace_data;
+  trace_data.expect = VMSW_GET_CALLING_ITEM;
+  trace_data.result = NULL;
+  
+  state.trace_function = stackwalker_trace_fn;
+  state.trace_data = (void *) &trace_data;
+
+  UpdateNCodeMap();
+  _Unwind_Backtrace (UnwindTraceFn, &state);
+
+  return trace_data.result;
+}
+
+struct StackWalkerNNLTraceData
+{
+  gswcc_expect expect;
+  ClassLoader *result;
+};
+
+_Unwind_Reason_Code
+_Jv_StackTrace::stackwalker_nnl_trace_fn (_Jv_UnwindState *state)
+{
+  StackWalkerNNLTraceData *trace_data = (StackWalkerNNLTraceData *)
+    state->trace_data;
+  _Jv_StackFrame *frame = &state->frames[state->pos];
+  FillInFrameInfo (frame);
+
+  if (!(frame->klass && frame->meth))
+    return _URC_NO_REASON;
+
+  switch (trace_data->expect)
+    {
+    case VMSW_GET_CALLING_ITEM:
+      JvAssert (frame->klass == &::gnu::classpath::VMStackWalker::class$);
+      trace_data->expect = JLRM_INVOKE_OR_CALLER;
+      break;
+
+    case JLRM_INVOKE_OR_CALLER:
+      if (frame->klass == &::java::lang::reflect::Method::class$
+	  && strcmp (frame->meth->name->chars(), "invoke") == 0)
+	trace_data->expect = CALLER;
+      else
+	trace_data->expect = CALLER_OF_CALLER;
+      break;
+
+    case CALLER:
+      trace_data->expect = CALLER_OF_CALLER;
+      break;
+
+    case CALLER_OF_CALLER:
+      ClassLoader *cl = frame->klass->getClassLoaderInternal ();
+      if (cl != NULL)
+	{
+	  trace_data->result = cl;
+	  return _URC_NORMAL_STOP;
+	}
+    }
+
+  return _URC_NO_REASON;
+}
+
+ClassLoader *
+_Jv_StackTrace::GetStackWalkerFirstNonNullLoader (void)
+{
+  int trace_size = 100;
+  _Jv_StackFrame frames[trace_size];
+  _Jv_UnwindState state (trace_size);
+  state.frames = (_Jv_StackFrame *) &frames;
+
+  StackWalkerNNLTraceData trace_data;
+  trace_data.expect = VMSW_GET_CALLING_ITEM;
+  trace_data.result = NULL;
+  
+  state.trace_function = stackwalker_nnl_trace_fn;
+  state.trace_data = (void *) &trace_data;
+
+  UpdateNCodeMap();
+  _Unwind_Backtrace (UnwindTraceFn, &state);
+
+  return trace_data.result;
+}