Re: PATCH [8/n]: Prepare x32: PR other/48007: Unwind library doesn't work with UNITS_PER_WORD > sizeof (void *)

["H.J. Lu" <hjl.tools@gmail.com>]

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On Tue, Aug 2, 2011 at 2:02 PM, Jason Merrill <jason@redhat.com> wrote:
> On 06/30/2011 04:47 PM, H.J. Lu wrote:
>>
>> +@defmac REG_VALUE_IN_UNWIND_CONTEXT
>> +
>> +Define this macro if the target stores register values as
>> +@code{_Unwind_Word} type in unwind context.  The default is to
>> +store register values as @code{void *} type.
>> +
>> +@end defmac
>
> This ought to suggest why a port would need to do this, namely if registers
> can be larger than void*.
>
>> +#ifdef REG_VALUE_IN_UNWIND_CONTEXT
>> +typedef _Unwind_Word _Unwind_Context_Reg_Val;
>> +
>> +#define _Unwind_IsExtendedContext(c) 1
>
> I still think that assuming extended context should be a separate target
> macro which is implied by REG_VALUE_IN_UNWIND_CONTEXT, but can also be
> defined separately by new ports.
>
> Otherwise it looks good to me.
>
> Jason
>

Here is the updated patch.  I updated REG_VALUE_IN_UNWIND_CONTEXT
document and added ASSUME_EXTENDED_UNWIND_CONTEXT.  OK for
trunk?

Thanks.


-- 
H.J.
-gcc/

2011-08-02  H.J. Lu  <hongjiu.lu@intel.com>

	* config.gcc (libgcc_tm_file): Add i386/value-unwind.h for
	Linux/x86.

	* system.h (REG_VALUE_IN_UNWIND_CONTEXT): Poisoned.
	(ASSUME_EXTENDED_UNWIND_CONTEXT): Likewise.

	* unwind-dw2.c (ASSUME_EXTENDED_UNWIND_CONTEXT): New.
	(_Unwind_Context_Reg_Val): Likewise.
	(_Unwind_Get_Unwind_Word): Likewise.
	(_Unwind_Get_Unwind_Context_Reg_Val): Likewise.
	(_Unwind_Context): Use _Unwind_Context_Reg_Val on the reg field.
	(_Unwind_IsExtendedContext): Check ASSUME_EXTENDED_UNWIND_CONTEXT
	for EXTENDED_CONTEXT_BIT.
	(__frame_state_for): Likewise.
	(uw_init_context_1): Likewise.
	(_Unwind_GetGR): Updated.
	(_Unwind_SetGR): Likewise.
	(_Unwind_GetGRPtr): Likewise.
	(_Unwind_SetGRPtr): Likewise.
	(_Unwind_SetGRValue): Likewise.
	(_Unwind_GRByValue): Likewise.
	(uw_install_context_1): Likewise.

	* doc/tm.texi.in: Document REG_VALUE_IN_UNWIND_CONTEXT and
	ASSUME_EXTENDED_UNWIND_CONTEXT.
	* doc/tm.texi: Regenerated.

libgcc/

2011-08-02  H.J. Lu  <hongjiu.lu@intel.com>

	* config/i386/value-unwind.h: New.
---

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gcc/

2011-08-02  H.J. Lu  <hongjiu.lu@intel.com>

	* config.gcc (libgcc_tm_file): Add i386/value-unwind.h for
	Linux/x86.

	* system.h (REG_VALUE_IN_UNWIND_CONTEXT): Poisoned.
	(ASSUME_EXTENDED_UNWIND_CONTEXT): Likewise.

	* unwind-dw2.c (ASSUME_EXTENDED_UNWIND_CONTEXT): New.
	(_Unwind_Context_Reg_Val): Likewise.
	(_Unwind_Get_Unwind_Word): Likewise.
	(_Unwind_Get_Unwind_Context_Reg_Val): Likewise.
	(_Unwind_Context): Use _Unwind_Context_Reg_Val on the reg field.
	(_Unwind_IsExtendedContext): Check ASSUME_EXTENDED_UNWIND_CONTEXT
	for EXTENDED_CONTEXT_BIT.
	(__frame_state_for): Likewise.
	(uw_init_context_1): Likewise.
	(_Unwind_GetGR): Updated.
	(_Unwind_SetGR): Likewise.
	(_Unwind_GetGRPtr): Likewise.
	(_Unwind_SetGRPtr): Likewise.
	(_Unwind_SetGRValue): Likewise.
	(_Unwind_GRByValue): Likewise.
	(uw_install_context_1): Likewise.

	* doc/tm.texi.in: Document REG_VALUE_IN_UNWIND_CONTEXT and
	ASSUME_EXTENDED_UNWIND_CONTEXT.
	* doc/tm.texi: Regenerated.

libgcc/

2011-08-02  H.J. Lu  <hongjiu.lu@intel.com>

	* config/i386/value-unwind.h: New.

diff --git a/gcc/config.gcc b/gcc/config.gcc
index 94f15d8..1ccd5f1 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -2671,6 +2671,7 @@ esac
 case ${target} in
 i[34567]86-*-linux* | x86_64-*-linux*)
 	tmake_file="${tmake_file} i386/t-pmm_malloc i386/t-i386"
+	libgcc_tm_file="${libgcc_tm_file} i386/value-unwind.h"
 	;;
 i[34567]86-*-* | x86_64-*-*)
 	tmake_file="${tmake_file} i386/t-gmm_malloc i386/t-i386"
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 097531f..74a2324 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -3725,6 +3725,24 @@ return @code{@var{regno}}.
 
 @end defmac
 
+@defmac REG_VALUE_IN_UNWIND_CONTEXT
+
+Define this macro if the target stores register values as
+@code{_Unwind_Word} type in unwind context.  It should be defined if
+target register size is larger than the size of @code{void *}.  The
+default is to store register values as @code{void *} type.
+
+@end defmac
+
+@defmac ASSUME_EXTENDED_UNWIND_CONTEXT
+
+Define this macro to be 1 if the target always uses extended unwind
+context with version, args_size and by_value fields.  If it is undefined,
+it will be defined to 1 when @code{REG_VALUE_IN_UNWIND_CONTEXT} is
+defined and 0 otherwise.
+
+@end defmac
+
 @node Elimination
 @subsection Eliminating Frame Pointer and Arg Pointer
 
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index 01beeb4..f63fe4a 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -3711,6 +3711,24 @@ return @code{@var{regno}}.
 
 @end defmac
 
+@defmac REG_VALUE_IN_UNWIND_CONTEXT
+
+Define this macro if the target stores register values as
+@code{_Unwind_Word} type in unwind context.  It should be defined if
+target register size is larger than the size of @code{void *}.  The
+default is to store register values as @code{void *} type.
+
+@end defmac
+
+@defmac ASSUME_EXTENDED_UNWIND_CONTEXT
+
+Define this macro to be 1 if the target always uses extended unwind
+context with version, args_size and by_value fields.  If it is undefined,
+it will be defined to 1 when @code{REG_VALUE_IN_UNWIND_CONTEXT} is
+defined and 0 otherwise.
+
+@end defmac
+
 @node Elimination
 @subsection Eliminating Frame Pointer and Arg Pointer
 
diff --git a/gcc/system.h b/gcc/system.h
index 7ac9859..783101d 100644
--- a/gcc/system.h
+++ b/gcc/system.h
@@ -802,7 +802,8 @@ extern void fancy_abort (const char *, int, const char *) ATTRIBUTE_NORETURN;
 /* Target macros only used for code built for the target, that have
    moved to libgcc-tm.h or have never been present elsewhere.  */
  #pragma GCC poison DECLARE_LIBRARY_RENAMES LIBGCC2_GNU_PREFIX		\
-	MD_UNWIND_SUPPORT ENABLE_EXECUTE_STACK
+	MD_UNWIND_SUPPORT ENABLE_EXECUTE_STACK \
+	REG_VALUE_IN_UNWIND_CONTEXT ASSUME_EXTENDED_UNWIND_CONTEXT
 
 /* Other obsolete target macros, or macros that used to be in target
    headers and were not used, and may be obsolete or may never have
diff --git a/gcc/unwind-dw2.c b/gcc/unwind-dw2.c
index 19da299..92aa233 100644
--- a/gcc/unwind-dw2.c
+++ b/gcc/unwind-dw2.c
@@ -59,12 +59,50 @@
 #define DWARF_REG_TO_UNWIND_COLUMN(REGNO) (REGNO)
 #endif
 
+#ifdef REG_VALUE_IN_UNWIND_CONTEXT
+typedef _Unwind_Word _Unwind_Context_Reg_Val;
+
+#ifndef ASSUME_EXTENDED_UNWIND_CONTEXT
+#define ASSUME_EXTENDED_UNWIND_CONTEXT 1
+#endif
+
+static inline _Unwind_Word
+_Unwind_Get_Unwind_Word (_Unwind_Context_Reg_Val val)
+{
+  return val;
+}
+
+static inline _Unwind_Context_Reg_Val
+_Unwind_Get_Unwind_Context_Reg_Val (_Unwind_Word val)
+{
+  return val;
+}
+#else
+typedef void *_Unwind_Context_Reg_Val;
+
+static inline _Unwind_Word
+_Unwind_Get_Unwind_Word (_Unwind_Context_Reg_Val val)
+{
+  return (_Unwind_Word) (_Unwind_Internal_Ptr) val;
+}
+
+static inline _Unwind_Context_Reg_Val
+_Unwind_Get_Unwind_Context_Reg_Val (_Unwind_Word val)
+{
+  return (_Unwind_Context_Reg_Val) (_Unwind_Internal_Ptr) val;
+}
+#endif
+
+#ifndef ASSUME_EXTENDED_UNWIND_CONTEXT
+#define ASSUME_EXTENDED_UNWIND_CONTEXT 0
+#endif
+
 /* This is the register and unwind state for a particular frame.  This
    provides the information necessary to unwind up past a frame and return
    to its caller.  */
 struct _Unwind_Context
 {
-  void *reg[DWARF_FRAME_REGISTERS+1];
+  _Unwind_Context_Reg_Val reg[DWARF_FRAME_REGISTERS+1];
   void *cfa;
   void *ra;
   void *lsda;
@@ -147,7 +185,8 @@ _Unwind_SetSignalFrame (struct _Unwind_Context *context, int val)
 static inline _Unwind_Word
 _Unwind_IsExtendedContext (struct _Unwind_Context *context)
 {
-  return context->flags & EXTENDED_CONTEXT_BIT;
+  return (ASSUME_EXTENDED_UNWIND_CONTEXT
+	  || (context->flags & EXTENDED_CONTEXT_BIT));
 }
 \f
 /* Get the value of register INDEX as saved in CONTEXT.  */
@@ -156,7 +195,7 @@ inline _Unwind_Word
 _Unwind_GetGR (struct _Unwind_Context *context, int index)
 {
   int size;
-  void *ptr;
+  _Unwind_Context_Reg_Val val;
 
 #ifdef DWARF_ZERO_REG
   if (index == DWARF_ZERO_REG)
@@ -166,18 +205,18 @@ _Unwind_GetGR (struct _Unwind_Context *context, int index)
   index = DWARF_REG_TO_UNWIND_COLUMN (index);
   gcc_assert (index < (int) sizeof(dwarf_reg_size_table));
   size = dwarf_reg_size_table[index];
-  ptr = context->reg[index];
+  val = context->reg[index];
 
   if (_Unwind_IsExtendedContext (context) && context->by_value[index])
-    return (_Unwind_Word) (_Unwind_Internal_Ptr) ptr;
+    return _Unwind_Get_Unwind_Word (val);
 
   /* This will segfault if the register hasn't been saved.  */
   if (size == sizeof(_Unwind_Ptr))
-    return * (_Unwind_Ptr *) ptr;
+    return * (_Unwind_Ptr *) (_Unwind_Internal_Ptr) val;
   else
     {
       gcc_assert (size == sizeof(_Unwind_Word));
-      return * (_Unwind_Word *) ptr;
+      return * (_Unwind_Word *) (_Unwind_Internal_Ptr) val;
     }
 }
 
@@ -209,11 +248,11 @@ _Unwind_SetGR (struct _Unwind_Context *context, int index, _Unwind_Word val)
 
   if (_Unwind_IsExtendedContext (context) && context->by_value[index])
     {
-      context->reg[index] = (void *) (_Unwind_Internal_Ptr) val;
+      context->reg[index] = _Unwind_Get_Unwind_Context_Reg_Val (val);
       return;
     }
 
-  ptr = context->reg[index];
+  ptr = (void *) (_Unwind_Internal_Ptr) context->reg[index];
 
   if (size == sizeof(_Unwind_Ptr))
     * (_Unwind_Ptr *) ptr = val;
@@ -232,7 +271,7 @@ _Unwind_GetGRPtr (struct _Unwind_Context *context, int index)
   index = DWARF_REG_TO_UNWIND_COLUMN (index);
   if (_Unwind_IsExtendedContext (context) && context->by_value[index])
     return &context->reg[index];
-  return context->reg[index];
+  return (void *) (_Unwind_Internal_Ptr) context->reg[index];
 }
 
 /* Set the pointer to a register INDEX as saved in CONTEXT.  */
@@ -243,7 +282,7 @@ _Unwind_SetGRPtr (struct _Unwind_Context *context, int index, void *p)
   index = DWARF_REG_TO_UNWIND_COLUMN (index);
   if (_Unwind_IsExtendedContext (context))
     context->by_value[index] = 0;
-  context->reg[index] = p;
+  context->reg[index] = (_Unwind_Context_Reg_Val) (_Unwind_Internal_Ptr) p;
 }
 
 /* Overwrite the saved value for register INDEX in CONTEXT with VAL.  */
@@ -254,10 +293,10 @@ _Unwind_SetGRValue (struct _Unwind_Context *context, int index,
 {
   index = DWARF_REG_TO_UNWIND_COLUMN (index);
   gcc_assert (index < (int) sizeof(dwarf_reg_size_table));
-  gcc_assert (dwarf_reg_size_table[index] == sizeof (_Unwind_Ptr));
+  gcc_assert (dwarf_reg_size_table[index] == sizeof (_Unwind_Context_Reg_Val));
 
   context->by_value[index] = 1;
-  context->reg[index] = (void *) (_Unwind_Internal_Ptr) val;
+  context->reg[index] = _Unwind_Get_Unwind_Context_Reg_Val (val);
 }
 
 /* Return nonzero if register INDEX is stored by value rather than
@@ -1215,7 +1254,8 @@ __frame_state_for (void *pc_target, struct frame_state *state_in)
   int reg;
 
   memset (&context, 0, sizeof (struct _Unwind_Context));
-  context.flags = EXTENDED_CONTEXT_BIT;
+  if (!ASSUME_EXTENDED_UNWIND_CONTEXT)
+    context.flags = EXTENDED_CONTEXT_BIT;
   context.ra = pc_target + 1;
 
   if (uw_frame_state_for (&context, &fs) != _URC_NO_REASON)
@@ -1453,7 +1493,8 @@ uw_init_context_1 (struct _Unwind_Context *context,
 
   memset (context, 0, sizeof (struct _Unwind_Context));
   context->ra = ra;
-  context->flags = EXTENDED_CONTEXT_BIT;
+  if (!ASSUME_EXTENDED_UNWIND_CONTEXT)
+    context->flags = EXTENDED_CONTEXT_BIT;
 
   code = uw_frame_state_for (context, &fs);
   gcc_assert (code == _URC_NO_REASON);
@@ -1532,8 +1573,8 @@ uw_install_context_1 (struct _Unwind_Context *current,
 
   for (i = 0; i < DWARF_FRAME_REGISTERS; ++i)
     {
-      void *c = current->reg[i];
-      void *t = target->reg[i];
+      void *c = (void *) (_Unwind_Internal_Ptr) current->reg[i];
+      void *t = (void *) (_Unwind_Internal_Ptr)target->reg[i];
 
       gcc_assert (current->by_value[i] == 0);
       if (target->by_value[i] && c)
diff --git a/libgcc/config/i386/value-unwind.h b/libgcc/config/i386/value-unwind.h
new file mode 100644
index 0000000..0dceb5c
--- /dev/null
+++ b/libgcc/config/i386/value-unwind.h
@@ -0,0 +1,26 @@
+/* Store register values as _Unwind_Word type in DWARF2 EH unwind context.
+   Copyright (C) 2011
+   Free Software Foundation, Inc.
+
+   This file is part of GCC.
+
+   GCC is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published
+   by the Free Software Foundation; either version 3, or (at your
+   option) any later version.
+
+   GCC is distributed in the hope that it will be useful, but WITHOUT
+   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+   License for more details.
+
+   You should have received a copy of the GNU General Public License and
+   a copy of the GCC Runtime Library Exception along with this program;
+   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Define this macro if the target stores register values as _Unwind_Word
+   type in unwind context.  Only enable it for x32.  */
+#if defined __x86_64 && !defined __LP64__
+# define REG_VALUE_IN_UNWIND_CONTEXT
+#endif