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
Sat Jun 25 23:36:00 GMT 2011


On Sat, Jun 25, 2011 at 1:19 PM, Joseph S. Myers
<joseph@codesourcery.com> wrote:
> On Sat, 25 Jun 2011, H.J. Lu wrote:
>
>> +#ifndef UNIQUE_UNWIND_CONTEXT
>
> The use of #ifndef seems to imply that this is a target macro, to be
> defined in libgcc_tm.h.  In that case it should be documented, and
> poisoned in system.h under the "only used for code built for the target"
> case, and this:
>
>> +#if defined __x86_64 && !defined __LP64__
>
> is inappropriate since you should instead put it in an appropriate header
> in libgcc/config/, rather than hardcoding an architecture-specific #if in
> an architecture-independent file.
>

Here is the updated patch.  OK for trunk?

Thanks.


-- 
H.J.
---
gcc/

2011-06-25  H.J. Lu  <hongjiu.lu@intel.com>

	PR other/48007
	* config.gcc (libgcc_tm_file): Add i386/unique-unwind.h for
	Linux/x86.

	* system.h (UNIQUE_UNWIND_CONTEXT): Poisoned.

	* unwind-dw2.c (_Unwind_Context): If UNIQUE_UNWIND_CONTEXT is
	defined, add dwarf_reg_size_table and value, remove version and
	by_value.
	(EXTENDED_CONTEXT_BIT): Don't define if UNIQUE_UNWIND_CONTEXT
	is defined.
	(_Unwind_IsExtendedContext): Likewise.
	(_Unwind_GetGR): Support UNIQUE_UNWIND_CONTEXT.
	(_Unwind_SetGR): Likewise.
	(_Unwind_GetGRPtr): Likewise.
	(_Unwind_SetGRPtr): Likewise.
	(_Unwind_SetGRValue): Likewise.
	(_Unwind_GRByValue): Likewise.
	(__frame_state_for): Initialize dwarf_reg_size_table field if
	UNIQUE_UNWIND_CONTEXT is defined.
	(uw_install_context_1): Likewise.  Support UNIQUE_UNWIND_CONTEXT.

	* doc/tm.texi.in: Document UNIQUE_UNWIND_CONTEXT.
	* doc/tm.texi: Regenerated.

libgcc/

2011-06-25  H.J. Lu  <hongjiu.lu@intel.com>

	* config/i386/unique-unwind.h: New file.
-------------- next part --------------
gcc/

2011-06-25  H.J. Lu  <hongjiu.lu@intel.com>

	PR other/48007
	* config.gcc (libgcc_tm_file): Add i386/unique-unwind.h for
	Linux/x86.

	* system.h (UNIQUE_UNWIND_CONTEXT): Poisoned.

	* unwind-dw2.c (_Unwind_Context): If UNIQUE_UNWIND_CONTEXT is
	defined, add dwarf_reg_size_table and value, remove version and
	by_value.
	(EXTENDED_CONTEXT_BIT): Don't define if UNIQUE_UNWIND_CONTEXT
	is defined.
	(_Unwind_IsExtendedContext): Likewise.
	(_Unwind_GetGR): Support UNIQUE_UNWIND_CONTEXT.
	(_Unwind_SetGR): Likewise.
	(_Unwind_GetGRPtr): Likewise.
	(_Unwind_SetGRPtr): Likewise.
	(_Unwind_SetGRValue): Likewise.
	(_Unwind_GRByValue): Likewise.
	(__frame_state_for): Initialize dwarf_reg_size_table field if
	UNIQUE_UNWIND_CONTEXT is defined.
	(uw_install_context_1): Likewise.  Support UNIQUE_UNWIND_CONTEXT.

	* doc/tm.texi.in: Document UNIQUE_UNWIND_CONTEXT.
	* doc/tm.texi: Regenerated.

libgcc/

2011-06-25  H.J. Lu  <hongjiu.lu@intel.com>

	* config/i386/unique-unwind.h: New file.

diff --git a/gcc/config.gcc b/gcc/config.gcc
index a1dbd1a..cdcabac 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -2627,6 +2648,7 @@ 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="${libgcc_tm_file} i386/unique-unwind.h"
 	;;
 i[34567]86-*-* | x86_64-*-*)
 	tmake_file="${tmake_file} i386/t-gmm_malloc i386/t-i386"
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 341628b..ad8543d 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -3701,6 +3701,13 @@ return @code{@var{regno}}.
 
 @end defmac
 
+@defmac UNIQUE_UNWIND_CONTEXT
+
+Define this macro if the target only supports single unqiue unwind
+context.  The default is to support multiple unwind contexts.
+
+@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 f7c16e9..9847014 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -3687,6 +3687,13 @@ return @code{@var{regno}}.
 
 @end defmac
 
+@defmac UNIQUE_UNWIND_CONTEXT
+
+Define this macro if the target only supports single unqiue unwind
+context.  The default is to support multiple unwind contexts.
+
+@end defmac
+
 @node Elimination
 @subsection Eliminating Frame Pointer and Arg Pointer
 
diff --git a/gcc/system.h b/gcc/system.h
index e02cbcd..e9771af 100644
--- a/gcc/system.h
+++ b/gcc/system.h
@@ -764,7 +764,7 @@ 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 UNIQUE_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..ed6d15f 100644
--- a/gcc/unwind-dw2.c
+++ b/gcc/unwind-dw2.c
@@ -69,6 +69,15 @@ struct _Unwind_Context
   void *ra;
   void *lsda;
   struct dwarf_eh_bases bases;
+#ifdef UNIQUE_UNWIND_CONTEXT
+  /* Used to check for unique _Unwind_Context.  */
+  void *dwarf_reg_size_table;
+  /* Signal frame context.  */
+#define SIGNAL_FRAME_BIT ((_Unwind_Word) 1 >> 0)
+  _Unwind_Word flags;
+  _Unwind_Word args_size;
+  _Unwind_Word value[DWARF_FRAME_REGISTERS+1];
+#else
   /* Signal frame context.  */
 #define SIGNAL_FRAME_BIT ((~(_Unwind_Word) 0 >> 1) + 1)
   /* Context which has version/args_size/by_value fields.  */
@@ -79,6 +88,7 @@ struct _Unwind_Context
   _Unwind_Word version;
   _Unwind_Word args_size;
   char by_value[DWARF_FRAME_REGISTERS+1];
+#endif
 };
 
 /* Byte size of every register managed by these routines.  */
@@ -144,11 +154,13 @@ _Unwind_SetSignalFrame (struct _Unwind_Context *context, int val)
     context->flags &= ~SIGNAL_FRAME_BIT;
 }
 
+#ifndef UNIQUE_UNWIND_CONTEXT
 static inline _Unwind_Word
 _Unwind_IsExtendedContext (struct _Unwind_Context *context)
 {
   return context->flags & EXTENDED_CONTEXT_BIT;
 }
+#endif
 

 /* Get the value of register INDEX as saved in CONTEXT.  */
 
@@ -168,8 +180,14 @@ _Unwind_GetGR (struct _Unwind_Context *context, int index)
   size = dwarf_reg_size_table[index];
   ptr = context->reg[index];
 
+#ifdef UNIQUE_UNWIND_CONTEXT
+  gcc_assert (context->dwarf_reg_size_table == &dwarf_reg_size_table);
+  if (context->reg[index] == &context->value[index])
+    return context->value[index];
+#else
   if (_Unwind_IsExtendedContext (context) && context->by_value[index])
     return (_Unwind_Word) (_Unwind_Internal_Ptr) ptr;
+#endif
 
   /* This will segfault if the register hasn't been saved.  */
   if (size == sizeof(_Unwind_Ptr))
@@ -207,11 +225,20 @@ _Unwind_SetGR (struct _Unwind_Context *context, int index, _Unwind_Word val)
   gcc_assert (index < (int) sizeof(dwarf_reg_size_table));
   size = dwarf_reg_size_table[index];
 
+#ifdef UNIQUE_UNWIND_CONTEXT
+  gcc_assert (context->dwarf_reg_size_table == &dwarf_reg_size_table);
+  if (context->reg[index] == &context->value[index])
+    {
+      context->value[index] = val;
+      return;
+    }
+#else
   if (_Unwind_IsExtendedContext (context) && context->by_value[index])
     {
       context->reg[index] = (void *) (_Unwind_Internal_Ptr) val;
       return;
     }
+#endif
 
   ptr = context->reg[index];
 
@@ -230,8 +257,10 @@ static inline void *
 _Unwind_GetGRPtr (struct _Unwind_Context *context, int index)
 {
   index = DWARF_REG_TO_UNWIND_COLUMN (index);
+#ifndef UNIQUE_UNWIND_CONTEXT
   if (_Unwind_IsExtendedContext (context) && context->by_value[index])
     return &context->reg[index];
+#endif
   return context->reg[index];
 }
 
@@ -241,8 +270,10 @@ static inline void
 _Unwind_SetGRPtr (struct _Unwind_Context *context, int index, void *p)
 {
   index = DWARF_REG_TO_UNWIND_COLUMN (index);
+#ifndef UNIQUE_UNWIND_CONTEXT
   if (_Unwind_IsExtendedContext (context))
     context->by_value[index] = 0;
+#endif
   context->reg[index] = p;
 }
 
@@ -254,10 +285,15 @@ _Unwind_SetGRValue (struct _Unwind_Context *context, int index,
 {
   index = DWARF_REG_TO_UNWIND_COLUMN (index);
   gcc_assert (index < (int) sizeof(dwarf_reg_size_table));
+#ifdef UNIQUE_UNWIND_CONTEXT
+  gcc_assert (dwarf_reg_size_table[index] == sizeof (_Unwind_Word));
+  context->value[index] = val;
+  context->reg[index] = &context->value[index];
+#else
   gcc_assert (dwarf_reg_size_table[index] == sizeof (_Unwind_Ptr));
-
   context->by_value[index] = 1;
   context->reg[index] = (void *) (_Unwind_Internal_Ptr) val;
+#endif
 }
 
 /* Return nonzero if register INDEX is stored by value rather than
@@ -267,7 +303,11 @@ static inline int
 _Unwind_GRByValue (struct _Unwind_Context *context, int index)
 {
   index = DWARF_REG_TO_UNWIND_COLUMN (index);
+#ifdef UNIQUE_UNWIND_CONTEXT
+  return context->reg[index] == &context->value[index];
+#else
   return context->by_value[index];
+#endif
 }
 
 /* Retrieve the return address for CONTEXT.  */
@@ -1215,7 +1255,11 @@ __frame_state_for (void *pc_target, struct frame_state *state_in)
   int reg;
 
   memset (&context, 0, sizeof (struct _Unwind_Context));
+#ifdef UNIQUE_UNWIND_CONTEXT
+  context.dwarf_reg_size_table = &dwarf_reg_size_table;
+#else
   context.flags = EXTENDED_CONTEXT_BIT;
+#endif
   context.ra = pc_target + 1;
 
   if (uw_frame_state_for (&context, &fs) != _URC_NO_REASON)
@@ -1453,7 +1497,11 @@ uw_init_context_1 (struct _Unwind_Context *context,
 
   memset (context, 0, sizeof (struct _Unwind_Context));
   context->ra = ra;
+#ifdef UNIQUE_UNWIND_CONTEXT
+  context->dwarf_reg_size_table = &dwarf_reg_size_table;
+#else
   context->flags = EXTENDED_CONTEXT_BIT;
+#endif
 
   code = uw_frame_state_for (context, &fs);
   gcc_assert (code == _URC_NO_REASON);
@@ -1535,8 +1583,13 @@ uw_install_context_1 (struct _Unwind_Context *current,
       void *c = current->reg[i];
       void *t = target->reg[i];
 
+#ifdef UNIQUE_UNWIND_CONTEXT
+      gcc_assert (current->reg[i] != &current->value[i]);
+      if (target->reg[i] == &target->value[i] && c)
+#else
       gcc_assert (current->by_value[i] == 0);
       if (target->by_value[i] && c)
+#endif
 	{
 	  _Unwind_Word w;
 	  _Unwind_Ptr p;
diff --git a/libgcc/config/i386/unique-unwind.h b/libgcc/config/i386/unique-unwind.h
new file mode 100644
index 0000000..7b11a9a
--- /dev/null
+++ b/libgcc/config/i386/unique-unwind.h
@@ -0,0 +1,26 @@
+/* Support DWARF2 EH unwind with single unqiue 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 only supports single unqiue unwind
+   context.  Only enable it for x32.  */
+#if defined __x86_64 && !defined __LP64__
+# define UNIQUE_UNWIND_CONTEXT
+#endif


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