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[PATCH 2/3] SH-2A FDPIC: PIC_OFFSET_TABLE_REG_CALL_CLOBBERED

This patch modifies PIC_OFFSET_TABLE_REG_CALL_CLOBBERED such that it's value can be modified at run time.

The reason for this is that we want to build compilers that support both regular and FDPIC code, and the ABI is different in each.

This feature is required by our SH-2A FDPIC (to follow), but has been split out here because parts of it are target independent, and parts touch other back ends.

OK to commit?

Andrew Stubbs 
2010-08-19  Joseph Myers  <joseph@codesourcery.com>

	gcc/
	* doc/tm.texi.in (PIC_OFFSET_TABLE_REG_CALL_CLOBBERED): Document to
	be zero or nonzero.
	* doc/tm.texi: Regenerate.
	* defaults.h (PIC_OFFSET_TABLE_REG_CALL_CLOBBERED): Define.
	* df-scan.c (df_get_exit_block_use_set), reginfo.c
	(init_reg_sets_1), rtlanal.c (rtx_unstable_p, rtx_varies_p):
	Handle new PIC_OFFSET_TABLE_REG_CALL_CLOBBERED semantics.
	* config/ia64/ia64.h (PIC_OFFSET_TABLE_REG_CALL_CLOBBERED): Define
	to 1.

---
 src/gcc-mainline/gcc/config/ia64/ia64.h |    2 +-
 src/gcc-mainline/gcc/defaults.h         |    4 ++++
 src/gcc-mainline/gcc/df-scan.c          |    5 ++---
 src/gcc-mainline/gcc/doc/tm.texi        |    5 +++--
 src/gcc-mainline/gcc/doc/tm.texi.in     |    5 +++--
 src/gcc-mainline/gcc/reginfo.c          |    5 ++---
 src/gcc-mainline/gcc/rtlanal.c          |    9 ++-------
 7 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/src/gcc-mainline/gcc/config/ia64/ia64.h b/src/gcc-mainline/gcc/config/ia64/ia64.h
index 39fa25c..b43d075 100644
--- a/src/gcc-mainline/gcc/config/ia64/ia64.h
+++ b/src/gcc-mainline/gcc/config/ia64/ia64.h
@@ -1359,7 +1359,7 @@ do {									\
 /* Define this macro if the register defined by `PIC_OFFSET_TABLE_REGNUM' is
    clobbered by calls.  */
 
-#define PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
+#define PIC_OFFSET_TABLE_REG_CALL_CLOBBERED 1
 
 
 /* The Overall Framework of an Assembler File.  */
diff --git a/src/gcc-mainline/gcc/defaults.h b/src/gcc-mainline/gcc/defaults.h
index 7aa227c..aaf6ea6 100644
--- a/src/gcc-mainline/gcc/defaults.h
+++ b/src/gcc-mainline/gcc/defaults.h
@@ -722,6 +722,10 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define PIC_OFFSET_TABLE_REGNUM INVALID_REGNUM
 #endif
 
+#ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
+#define PIC_OFFSET_TABLE_REG_CALL_CLOBBERED 0
+#endif
+
 #ifndef TARGET_DLLIMPORT_DECL_ATTRIBUTES
 #define TARGET_DLLIMPORT_DECL_ATTRIBUTES 0
 #endif
diff --git a/src/gcc-mainline/gcc/df-scan.c b/src/gcc-mainline/gcc/df-scan.c
index b4633ab..8b17ae2 100644
--- a/src/gcc-mainline/gcc/df-scan.c
+++ b/src/gcc-mainline/gcc/df-scan.c
@@ -4032,14 +4032,13 @@ df_get_exit_block_use_set (bitmap exit_block_uses)
 #endif
     }
 
-#ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
   /* Many architectures have a GP register even without flag_pic.
      Assume the pic register is not in use, or will be handled by
      other means, if it is not fixed.  */
-  if ((unsigned) PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
+  if (!PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
+      && (unsigned) PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
       && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
     bitmap_set_bit (exit_block_uses, PIC_OFFSET_TABLE_REGNUM);
-#endif
 
   /* Mark all global registers, and all registers used by the
      epilogue as being live at the end of the function since they
diff --git a/src/gcc-mainline/gcc/doc/tm.texi b/src/gcc-mainline/gcc/doc/tm.texi
index 3e38618..7e8765b 100644
--- a/src/gcc-mainline/gcc/doc/tm.texi
+++ b/src/gcc-mainline/gcc/doc/tm.texi
@@ -7128,8 +7128,9 @@ when @code{flag_pic} is true).
 @end defmac
 
 @defmac PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
-Define this macro if the register defined by
-@code{PIC_OFFSET_TABLE_REGNUM} is clobbered by calls.  Do not define
+A C expression that is nonzero if the register defined by
+@code{PIC_OFFSET_TABLE_REGNUM} is clobbered by calls.  If not defined,
+the default is zero.  Do not define
 this macro if @code{PIC_OFFSET_TABLE_REGNUM} is not defined.
 @end defmac
 
diff --git a/src/gcc-mainline/gcc/doc/tm.texi.in b/src/gcc-mainline/gcc/doc/tm.texi.in
index 6358916..4d13cbe 100644
--- a/src/gcc-mainline/gcc/doc/tm.texi.in
+++ b/src/gcc-mainline/gcc/doc/tm.texi.in
@@ -7123,8 +7123,9 @@ when @code{flag_pic} is true).
 @end defmac
 
 @defmac PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
-Define this macro if the register defined by
-@code{PIC_OFFSET_TABLE_REGNUM} is clobbered by calls.  Do not define
+A C expression that is nonzero if the register defined by
+@code{PIC_OFFSET_TABLE_REGNUM} is clobbered by calls.  If not defined,
+the default is zero.  Do not define
 this macro if @code{PIC_OFFSET_TABLE_REGNUM} is not defined.
 @end defmac
 
diff --git a/src/gcc-mainline/gcc/reginfo.c b/src/gcc-mainline/gcc/reginfo.c
index 0fc86d3..89965da 100644
--- a/src/gcc-mainline/gcc/reginfo.c
+++ b/src/gcc-mainline/gcc/reginfo.c
@@ -495,10 +495,9 @@ init_reg_sets_1 (void)
       else if (i == ARG_POINTER_REGNUM && fixed_regs[i])
 	;
 #endif
-#ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
-      else if (i == (unsigned) PIC_OFFSET_TABLE_REGNUM && fixed_regs[i])
+      else if (!PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
+	       && i == (unsigned) PIC_OFFSET_TABLE_REGNUM && fixed_regs[i])
 	;
-#endif
       else if (CALL_REALLY_USED_REGNO_P (i))
         {
 	  SET_HARD_REG_BIT (regs_invalidated_by_call, i);
diff --git a/src/gcc-mainline/gcc/rtlanal.c b/src/gcc-mainline/gcc/rtlanal.c
index f9e6871..4331f41 100644
--- a/src/gcc-mainline/gcc/rtlanal.c
+++ b/src/gcc-mainline/gcc/rtlanal.c
@@ -118,13 +118,11 @@ rtx_unstable_p (const_rtx x)
 	  /* The arg pointer varies if it is not a fixed register.  */
 	  || (x == arg_pointer_rtx && fixed_regs[ARG_POINTER_REGNUM]))
 	return 0;
-#ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
       /* ??? When call-clobbered, the value is stable modulo the restore
 	 that must happen after a call.  This currently screws up local-alloc
 	 into believing that the restore is not needed.  */
-      if (x == pic_offset_table_rtx)
+      if (!PIC_OFFSET_TABLE_REG_CALL_CLOBBERED && x == pic_offset_table_rtx)
 	return 0;
-#endif
       return 1;
 
     case ASM_OPERANDS:
@@ -197,14 +195,11 @@ rtx_varies_p (const_rtx x, bool for_alias)
 	  || (x == arg_pointer_rtx && fixed_regs[ARG_POINTER_REGNUM]))
 	return 0;
       if (x == pic_offset_table_rtx
-#ifdef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
 	  /* ??? When call-clobbered, the value is stable modulo the restore
 	     that must happen after a call.  This currently screws up
 	     local-alloc into believing that the restore is not needed, so we
 	     must return 0 only if we are called from alias analysis.  */
-	  && for_alias
-#endif
-	  )
+	  && (!PIC_OFFSET_TABLE_REG_CALL_CLOBBERED || for_alias))
 	return 0;
       return 1;
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