Enable gcj on ARM EABI

Enable gcj on ARM EABI

[Andrew Haley]

Add soft-float support for ARM libffi.

Add EABI exception handling.

Stub backtraces -- just for the time being.

Andrew.


2007-07-27  Andrew Haley  <aph@redhat.com>

	* configure.ac (noconfigdirs): Remove target-libffi and
	target-libjava.

2007-07-27  Andrew Haley  <aph@redhat.com>

	* gnu/classpath/natVMStackWalker.cc (GET_CALLING_CLASS): Stub for
	ARM EABI.
	* exception.cc (get_exception_header_from_ue): New.
	(get_ttype_entry): ARM EABI version.
	(PERSONALITY_FUNCTION): Add ARM EABI code.
	* sysdep/arm/backtrace.h: New file.
	* stacktrace.cc (_URC_NORMAL_STOP): New.
	* configure.ac (extra_ldflags_libjava): Add libsupc++.la for ARM
	EABI.
	* configure.host (BACKTRACESPEC): Add arm/backtrace.h.

2007-07-27  Andrew Haley  <aph@redhat.com>

	* src/arm/sysv.S (ffi_closure_SYSV): Add soft-float.

Index: configure
===================================================================
--- configure	(revision 126800)
+++ configure	(working copy)
@@ -2236,8 +2236,8 @@
     noconfigdirs="$noconfigdirs target-libffi target-qthreads"
     ;;
   arm*-*-linux-gnueabi)
-    noconfigdirs="$noconfigdirs target-libffi target-qthreads"
-    noconfigdirs="$noconfigdirs target-libjava target-libobjc"
+    noconfigdirs="$noconfigdirs target-qthreads"
+    noconfigdirs="$noconfigdirs target-libobjc"
     case ${with_newlib} in
       no) noconfigdirs="$noconfigdirs target-newlib target-libgloss"
     esac
Index: libffi/src/arm/sysv.S
===================================================================
--- libffi/src/arm/sysv.S	(revision 126800)
+++ libffi/src/arm/sysv.S	(working copy)
@@ -225,12 +225,28 @@
 	bl	ffi_closure_SYSV_inner
 	cmp	r0, #FFI_TYPE_INT
 	beq	.Lretint
+
 	cmp	r0, #FFI_TYPE_FLOAT
+#ifdef __SOFTFP__
+	beq	.Lretint
+#else
 	beq	.Lretfloat
+#endif
+
 	cmp	r0, #FFI_TYPE_DOUBLE
+#ifdef __SOFTFP__
+	beq	.Lretlonglong
+#else
 	beq	.Lretdouble
+#endif
+
 	cmp	r0, #FFI_TYPE_LONGDOUBLE
+#ifdef __SOFTFP__
+	beq	.Lretlonglong
+#else
 	beq	.Lretlongdouble
+#endif
+
 	cmp	r0, #FFI_TYPE_SINT64
 	beq	.Lretlonglong
 .Lclosure_epilogue:
@@ -243,6 +259,8 @@
 	ldr	r0, [sp]
 	ldr	r1, [sp, #4]
 	b	.Lclosure_epilogue
+
+#ifndef __SOFTFP__
 .Lretfloat:
 	ldfs	f0, [sp]
 	b	.Lclosure_epilogue
@@ -252,6 +270,8 @@
 .Lretlongdouble:
 	ldfd	f0, [sp]
 	b	.Lclosure_epilogue
+#endif
+
 .ffi_closure_SYSV_end:
         .size    CNAME(ffi_closure_SYSV),.ffi_closure_SYSV_end-CNAME(ffi_closure_SYSV)
 
Index: libjava/configure.host
===================================================================
--- libjava/configure.host	(revision 126800)
+++ libjava/configure.host	(working copy)
@@ -86,6 +86,7 @@
   arm*-linux*)
 	libgcj_interpreter=yes
 	sysdeps_dir=arm
+	fallback_backtrace_h=sysdep/arm/backtrace.h
 	;;
   mips-tx39-*|mipstx39-unknown-*)
 	libgcj_flags="${libgcj_flags} -G 0"
Index: libjava/configure.ac
===================================================================
--- libjava/configure.ac	(revision 126800)
+++ libjava/configure.ac	(working copy)
@@ -787,6 +787,9 @@
     # on Darwin -single_module speeds up loading of the dynamic libraries.
     extra_ldflags_libjava=-Wl,-single_module
     ;;
+arm*linux*eabi)
+    extra_ldflags_libjava=../libstdc++-v3/libsupc++/libsupc++.la
+    ;;
 esac
 AC_SUBST(extra_ldflags_libjava)
 
Index: libjava/stacktrace.cc
===================================================================
--- libjava/stacktrace.cc	(revision 126800)
+++ libjava/stacktrace.cc	(working copy)
@@ -39,6 +39,10 @@
 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 
Index: libjava/sysdep/arm/backtrace.h
===================================================================
--- libjava/sysdep/arm/backtrace.h	(revision 0)
+++ libjava/sysdep/arm/backtrace.h	(revision 0)
@@ -0,0 +1,46 @@
+// backtrace.h - Fallback backtrace implementation. default implementation.
+
+/* 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.  */
+
+#ifndef __SYSDEP_BACKTRACE_H__
+#define __SYSDEP_BACKTRACE_H__
+
+#include <java-stack.h>
+
+extern "C"
+{
+/* Unwind through the call stack calling TRACE_FN with STATE for every stack
+   frame.  Returns the reason why the unwinding was stopped.  */
+#ifdef __ARM_EABI_UNWINDER__
+#undef _Unwind_GetIPInfo
+#define _Unwind_GetIPInfo(ctx,ip_before_insn) \
+  (*(ip_before_insn) = 1, (ctx)->ret_addr)
+
+#undef _Unwind_GetRegionStart
+#define _Unwind_GetRegionStart(ctx) \
+  0
+
+#undef _Unwind_Backtrace
+#define _Unwind_Backtrace(trace_fn,state_ptr) \
+  (fallback_backtrace (trace_fn, state_ptr))
+
+#define _Unwind_FindEnclosingFunction(PC) \
+  (PC)
+
+_Unwind_Reason_Code
+fallback_backtrace (_Unwind_Reason_Code (*)(struct _Unwind_Context*, void*), _Jv_UnwindState *)
+#else
+_Unwind_Reason_Code
+fallback_backtrace (_Unwind_Trace_Fn, _Jv_UnwindState *)
+#endif
+{
+  return _URC_NO_REASON;
+}
+}
+#endif
Index: libjava/configure
===================================================================
--- libjava/configure	(revision 126800)
+++ libjava/configure	(working copy)
@@ -20370,6 +20370,9 @@
     # on Darwin -single_module speeds up loading of the dynamic libraries.
     extra_ldflags_libjava=-Wl,-single_module
     ;;
+arm*linux*eabi)
+    extra_ldflags_libjava=../libstdc++-v3/libsupc++/libsupc++.la
+    ;;
 esac
 
 
Index: libjava/exception.cc
===================================================================
--- libjava/exception.cc	(revision 126800)
+++ libjava/exception.cc	(working copy)
@@ -58,8 +58,23 @@
   _Unwind_Exception unwindHeader;
 };
 
+#ifdef __ARM_EABI_UNWINDER__
 // This is the exception class we report -- "GNUCJAVA".
+
 const _Unwind_Exception_Class __gcj_exception_class
+  = {'G', 'N', 'U', 'C', 'J', 'A', 'V', 'A'};
+
+static inline java_exception_header *
+get_exception_header_from_ue (_Unwind_Exception *exc)
+{
+  return reinterpret_cast<java_exception_header *>(exc + 1) - 1;
+}
+
+extern "C" void __cxa_begin_cleanup (_Unwind_Exception*);
+
+#else // !__ARM_EABI_UNWINDER__
+// This is the exception class we report -- "GNUCJAVA".
+const _Unwind_Exception_Class __gcj_exception_class
 = ((((((((_Unwind_Exception_Class) 'G' 
          << 8 | (_Unwind_Exception_Class) 'N')
         << 8 | (_Unwind_Exception_Class) 'U')
@@ -75,6 +90,7 @@
 {
   return reinterpret_cast<java_exception_header *>(exc + 1) - 1;
 }
+#endif // !__ARM_EABI_UNWINDER__
 
 /* Perform a throw, Java style. Throw will unwind through this call,
    so there better not be any handlers or exception thrown here. */
@@ -89,7 +105,8 @@
     value = new java::lang::NullPointerException ();
   xh->value = value;
 
-  xh->unwindHeader.exception_class = __gcj_exception_class;
+  memcpy (&xh->unwindHeader.exception_class, &__gcj_exception_class,
+	  sizeof xh->unwindHeader.exception_class);
   xh->unwindHeader.exception_cleanup = NULL;
 
   /* We're happy with setjmp/longjmp exceptions or region-based
@@ -159,7 +176,22 @@
   return p;
 }
 
+#ifdef __ARM_EABI_UNWINDER__
+
 static void **
+get_ttype_entry(_Unwind_Context *, lsda_header_info* info, _uleb128_t i)
+{
+  _Unwind_Ptr ptr;
+
+  ptr = (_Unwind_Ptr) (info->TType - (i * 4));
+  ptr = _Unwind_decode_target2(ptr);
+  
+  return reinterpret_cast<void **>(ptr);
+}
+
+#else
+
+static void **
 get_ttype_entry (_Unwind_Context *context, lsda_header_info *info, long i)
 {
   _Unwind_Ptr ptr;
@@ -170,6 +202,7 @@
   return reinterpret_cast<void **>(ptr);
 }
 
+#endif
 
 // Using a different personality function name causes link failures
 // when trying to mix code using different exception handling models.
@@ -180,12 +213,28 @@
 #define PERSONALITY_FUNCTION	__gcj_personality_v0
 #endif
 
+#define CONTINUE_UNWINDING \
+  do								\
+    {								\
+      if (__gnu_unwind_frame(ue_header, context) != _URC_OK)	\
+	return _URC_FAILURE;					\
+      return _URC_CONTINUE_UNWIND;				\
+    }								\
+  while (0)
+
+#ifdef __ARM_EABI_UNWINDER__
 extern "C" _Unwind_Reason_Code
+PERSONALITY_FUNCTION (_Unwind_State state,
+		      struct _Unwind_Exception* ue_header,
+		      struct _Unwind_Context* context)
+#else
+extern "C" _Unwind_Reason_Code
 PERSONALITY_FUNCTION (int version,
 		      _Unwind_Action actions,
 		      _Unwind_Exception_Class exception_class,
 		      struct _Unwind_Exception *ue_header,
 		      struct _Unwind_Context *context)
+#endif
 {
   java_exception_header *xh = get_exception_header_from_ue (ue_header);
 
@@ -197,16 +246,56 @@
   int handler_switch_value;
   bool saw_cleanup;
   bool saw_handler;
+  bool foreign_exception;
   int ip_before_insn = 0;
 
+#ifdef __ARM_EABI_UNWINDER__
+  _Unwind_Action actions;
 
+  switch (state & _US_ACTION_MASK)
+    {
+    case _US_VIRTUAL_UNWIND_FRAME:
+      actions = _UA_SEARCH_PHASE;
+      break;
+
+    case _US_UNWIND_FRAME_STARTING:
+      actions = _UA_CLEANUP_PHASE;
+      if (!(state & _US_FORCE_UNWIND)
+	  && ue_header->barrier_cache.sp == _Unwind_GetGR(context, 13))
+	actions |= _UA_HANDLER_FRAME;
+      break;
+
+    case _US_UNWIND_FRAME_RESUME:
+      CONTINUE_UNWINDING;
+      break;
+
+    default:
+      std::abort();
+    }
+  actions |= state & _US_FORCE_UNWIND;
+
+  // We don't know which runtime we're working with, so can't check this.
+  // However the ABI routines hide this from us, and we don't actually need
+  // to know.
+  foreign_exception = false;
+
+  // The dwarf unwinder assumes the context structure holds things like the
+  // function and LSDA pointers.  The ARM implementation caches these in
+  // the exception header (UCB).  To avoid rewriting everything we make the
+  // virtual IP register point at the UCB.
+  ip = (_Unwind_Ptr) ue_header;
+  _Unwind_SetGR(context, 12, ip);
+
+#else
   // Interface version check.
   if (version != 1)
     return _URC_FATAL_PHASE1_ERROR;
+  foreign_exception = exception_class != __gcj_exception_class)
+#endif
 
   // Shortcut for phase 2 found handler for domestic exception.
   if (actions == (_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME)
-      && exception_class == __gcj_exception_class)
+      && !foreign_exception)
     {
       handler_switch_value = xh->handlerSwitchValue;
       landing_pad = xh->landingPad;
@@ -227,17 +316,17 @@
 
   // If no LSDA, then there are no handlers or cleanups.
   if (! language_specific_data)
-    return _URC_CONTINUE_UNWIND;
+    CONTINUE_UNWINDING;
 
   // Parse the LSDA header.
   p = parse_lsda_header (context, language_specific_data, &info);
 #ifdef HAVE_GETIPINFO
   ip = _Unwind_GetIPInfo (context, &ip_before_insn);
-  if (! ip_before_insn)
-    --ip;
 #else
   ip = _Unwind_GetIP (context) - 1;
 #endif
+  if (! ip_before_insn)
+    --ip;
   landing_pad = 0;
   action_record = 0;
   handler_switch_value = 0;
@@ -296,7 +385,7 @@
   // If ip is not present in the table, C++ would call terminate.
   // ??? It is perhaps better to tweek the LSDA so that no-action
   // is mapped to no-entry for Java.
-  return _URC_CONTINUE_UNWIND;
+  CONTINUE_UNWINDING;
 
  found_something:
   saw_cleanup = false;
@@ -334,7 +423,7 @@
 	  // During forced unwinding, we only run cleanups.  With a
 	  // foreign exception class, we have no class info to match.
 	  else if ((actions & _UA_FORCE_UNWIND)
-	      || exception_class != __gcj_exception_class)
+		   || foreign_exception)
 	    ;
 
 	  else if (ar_filter > 0)
@@ -374,15 +463,15 @@
     }
 
   if (! saw_handler && ! saw_cleanup)
-    return _URC_CONTINUE_UNWIND;
+	CONTINUE_UNWINDING;
 
   if (actions & _UA_SEARCH_PHASE)
     {
       if (! saw_handler)
-	return _URC_CONTINUE_UNWIND;
+	CONTINUE_UNWINDING;
 
       // For domestic exceptions, we cache data from phase 1 for phase 2.
-      if (exception_class == __gcj_exception_class)
+      if (! foreign_exception)
         {
           xh->handlerSwitchValue = handler_switch_value;
           xh->landingPad = landing_pad;
@@ -396,5 +485,9 @@
   _Unwind_SetGR (context, __builtin_eh_return_data_regno (1),
 		 handler_switch_value);
   _Unwind_SetIP (context, landing_pad);
+#ifdef __ARM_EABI_UNWINDER__
+  if (saw_cleanup)
+    __cxa_begin_cleanup(ue_header);
+#endif
   return _URC_INSTALL_CONTEXT;
 }
Index: libjava/gnu/classpath/natVMStackWalker.cc
===================================================================
--- libjava/gnu/classpath/natVMStackWalker.cc	(revision 126800)
+++ libjava/gnu/classpath/natVMStackWalker.cc	(working copy)
@@ -19,6 +19,7 @@
 #include <java/lang/ClassLoader.h>
 #include <java/lang/Class.h>
 
+#ifndef __ARM_EABI_UNWINDER__
 // Return the class of the method that contains PC.
 // This is a macro not a function, since defining it as one would
 // introduce an extra frame on the stack.  */
@@ -44,6 +45,9 @@
 									\
   klass;								\
  })
+#else
+#define GET_CALLING_CLASS(PC) NULL
+#endif
 
 JArray<jclass> *
 gnu::classpath::VMStackWalker::getClassContext(void)

Re: Enable gcj on ARM EABI

[Andrew Haley]

Andrew Haley writes:
 > Add soft-float support for ARM libffi.
 > 
 > Add EABI exception handling.
 > 
 > Stub backtraces -- just for the time being.
 > 
 > Andrew.
 > 
 > 
 > 2007-07-27  Andrew Haley  <aph@redhat.com>
 > 
 > 	* configure.ac (noconfigdirs): Remove target-libffi and
 > 	target-libjava.
 > 

I posted this a month ago.  It's a toplevel patch that enables libjava
for ARM EABI.

As libjava on EABI passes all tests, I guess it's OK.

Andrew.

Re: Enable gcj on ARM EABI

[Paolo Bonzini]

>  > 2007-07-27  Andrew Haley  <aph@redhat.com>
>  > 
>  > 	* configure.ac (noconfigdirs): Remove target-libffi and
>  > 	target-libjava.
>  > 
> 
> I posted this a month ago.  It's a toplevel patch that enables libjava
> for ARM EABI.
> 
> As libjava on EABI passes all tests, I guess it's OK.

Of course, I must have missed it.  I left for holiday on the 28th indeed.

Paolo