Re: PATCH: New optimization, partitioning hot/cold basic blocks

[Andrew Pinski <pinskia at physics dot uc dot edu>]

On Apr 9, 2004, at 23:31, Andrew Pinski wrote:

> On Mar 16, 2004, at 19:42, Caroline Tice wrote:
>
> > > > + #define SECTION_FORMAT_STRING ".section\t\"%s\"\n\t.align 2\n"
> > >
> > > What is this for?
> >
> > To make sure the correct alignments, "dots", etc. end up being output 
> > for whichever architecture
> > we are on, when writing out the assembly directive for changing 
> > between hot/cold sections.  Yes, this
> > *is* necessary.  Without it I get bugs on both architectures I've 
> > tried this on.
>
> Well since .align is not supported on all targets, I think you should 
> be using ASM_OUTPUT_ALIGN instead.  So this part of the patch is wrong 
> for some targets.
>
> Also again some targets do not support .section so this is wrong for 
> most of them,
> in fact darwin did not support the attribute section until lately.  
> This is what is
> causing the problem on MIPS as O32 ABI does not support .section.  
> Also this will cause
> a bootstrap failure on i686-pc-cygwin which also does not support 
> .section or named sections.
>
> You should check targetm.have_named_sections instead and use the old 
> way if false then.
> have_named_sections was added back in 2001 by RTH so I think that is 
> why RTH was asking
> this question of "what is this for?"


This patch implements my suggestions and I tested on i686-openbsd3.1 
which does not support .section.
Plus it removes the unused Target defines which I remove the usage of.

OK after testing on sparc-solaris, i686-pc-linux-gnu, and other targets 
that are effected?

Thanks,
Andrew Pinski

ChangeLog:

	* varasm.c (text_section): Use TEXT_SECTION_ASM_OP and
	ASM_OUTPUT_ALIGN instead of SECTION_FORMAT_STRING
	and NORMAL_TEXT_SECTION_NAME.
	(unlikely_text_section): Check targetm.have_named_sections
	instead of TARGET_ASM_NAMED_SECTION and use TEXT_SECTION_ASM_OP
	instead of SECTION_FORMAT_STRING.
	* config/mips/iris5.h (current_section_name): Add 
in_unlikely_executed_text
	case and move the abort into the switch.
	* config/rs6000/sysv4.h (HOT_TEXT_SECTION_NAME): Remove.
	(NORMAL_TEXT_SECTION_NAME): Remove.
	(UNLIKELY_EXECUTED_TEXT_SECTION_NAME): Remove.
	(SECTION_FORMAT_STRING): Remove.
	* defaults.h (SECTION_FORMAT_STRING): Remove.
	* tm.texi (NORMAL_TEXT_SECTION_NAME): Remove.
	(SECTION_FORMAT_STRING): Remove.


Patch:
Index: defaults.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/defaults.h,v
retrieving revision 1.134
diff -u -d -b -w -u -p -r1.134 defaults.h
--- defaults.h	9 Apr 2004 19:57:41 -0000	1.134
+++ defaults.h	10 Apr 2004 20:49:40 -0000
@@ -631,10 +631,6 @@ You Lose!  You must define PREFERRED_DEB
 #define UNLIKELY_EXECUTED_TEXT_SECTION_NAME "text.unlikely"
 #endif

-#ifndef SECTION_FORMAT_STRING
-#define SECTION_FORMAT_STRING "\t.section\t%s\n\t.align 2\n"
-#endif
-
 #ifndef HAS_LONG_COND_BRANCH
 #define HAS_LONG_COND_BRANCH 0
 #endif
Index: varasm.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/varasm.c,v
retrieving revision 1.419
diff -u -d -b -w -u -p -r1.419 varasm.c
--- varasm.c	9 Apr 2004 19:57:43 -0000	1.419
+++ varasm.c	10 Apr 2004 20:49:42 -0000
@@ -208,7 +208,8 @@ text_section (void)
   if (in_section != in_text)
     {
       in_section = in_text;
-      fprintf (asm_out_file, SECTION_FORMAT_STRING, 
NORMAL_TEXT_SECTION_NAME);
+      ASM_OUTPUT_ALIGN (asm_out_file, 2);
+      fprintf (asm_out_file, "%s\n", TEXT_SECTION_ASM_OP);
     }
 }

@@ -221,15 +222,15 @@ unlikely_text_section (void)
       &&  (in_section != in_named
 	   || strcmp (in_named_name, UNLIKELY_EXECUTED_TEXT_SECTION_NAME) != 
0))
     {
-#ifdef TARGET_ASM_NAMED_SECTION
-	
+      if (targetm.have_named_sections)
       named_section (NULL_TREE, UNLIKELY_EXECUTED_TEXT_SECTION_NAME, 
0);
-
-#else
+      else
+	{
       in_section = in_unlikely_executed_text;
-      fprintf (asm_out_file, SECTION_FORMAT_STRING,
-	       UNLIKELY_EXECUTED_TEXT_SECTION_NAME);
-#endif /* ifdef TARGET_ASM_NAMED_SECTION */
+	  ASM_OUTPUT_ALIGN (asm_out_file, 2);
+	  fprintf (asm_out_file, "%s\n", TEXT_SECTION_ASM_OP);
+	}
+
       if (!unlikely_section_label_printed)
 	{
 	  fprintf (asm_out_file, "__%s_unlikely_section:\n",
Index: config/mips/iris5.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/mips/iris5.h,v
retrieving revision 1.29
diff -u -d -b -w -u -p -r1.29 iris5.h
--- config/mips/iris5.h	17 Feb 2004 20:42:53 -0000	1.29
+++ config/mips/iris5.h	10 Apr 2004 20:49:42 -0000
@@ -213,6 +213,7 @@ current_section_name (void)						\
   switch (in_section)							\
     {									\
     case no_section:	return NULL;					\
+    case in_unlikely_executed_text:					\
     case in_text:	return ".text";					\
     case in_data:	return ".data";					\
     case in_bss:	return ".bss";					\
@@ -223,8 +224,8 @@ current_section_name (void)						\
 	return ".rdata";						\
     case in_named:							\
       return in_named_name;						\
+    default: abort();							\
     }									\
-  abort ();								\
 }									\
 									\
 unsigned int								\
Index: config/rs6000/sysv4.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/rs6000/sysv4.h,v
retrieving revision 1.147
diff -u -d -b -w -u -p -r1.147 sysv4.h
--- config/rs6000/sysv4.h	9 Apr 2004 19:57:46 -0000	1.147
+++ config/rs6000/sysv4.h	10 Apr 2004 20:49:42 -0000
@@ -434,11 +434,6 @@ do {									\

 #define	BSS_SECTION_ASM_OP	"\t.section\t\".bss\""

-#define HOT_TEXT_SECTION_NAME ".text"
-#define NORMAL_TEXT_SECTION_NAME ".text"
-#define UNLIKELY_EXECUTED_TEXT_SECTION_NAME ".text.unlikely"
-#define SECTION_FORMAT_STRING ".section\t\"%s\"\n\t.align 2\n"
-
 /* Override elfos.h definition.  */
 #undef	INIT_SECTION_ASM_OP
 #define	INIT_SECTION_ASM_OP "\t.section\t\".init\",\"ax\""
Index: doc/tm.texi
===================================================================
RCS file: /cvs/gcc/gcc/gcc/doc/tm.texi,v
retrieving revision 1.319
diff -u -d -b -w -u -p -r1.319 tm.texi
--- doc/tm.texi	9 Apr 2004 19:57:47 -0000	1.319
+++ doc/tm.texi	10 Apr 2004 20:49:43 -0000
@@ -5802,13 +5802,6 @@ frequently executed functions of the pro
 a default definition if the target supports named sections.
 @end defmac

-@defmac NORMAL_TEXT_SECTION_NAME
-If defined, a C string constant for the name of the section containing 
code
-that does not go into the ``unlikely executed text'' partition.  This 
is used
-as part of the optimization that partitions hot and cold basic blocks 
into
-separate sections in the .o and executable files.
-@end defmac
-
 @defmac UNLIKELY_EXECUTED_TEXT_SECTION_NAME
 If defined, a C string constant for the name of the section containing 
unlikely
 executed functions in the program.
@@ -5858,12 +5851,6 @@ If defined, a C expression whose value i
 containing the assembler operation to identify the following data as
 finalization code.  If not defined, GCC will assume such a section does
 not exist.
-@end defmac
-
-@defmac SECTION_FORMAT_STRING
-If defined, format string used by fprintf to write out the
-text section headers for the hot and cold sections of the
-assembly file, when hot and cold partitioning is being performed.
 @end defmac

 @defmac CRT_CALL_STATIC_FUNCTION (@var{section_op}, @var{function})