configure.in: Check whether assembler supports section merging.

	* configure.in: Check whether assembler supports section merging.
	* config.in: Rebuilt.
	* configure: Rebuilt.
	* varasm.c (variable_section, output_constant_pool): Pass alignment
	to SELECT_SECTION and SELECT_RTX_SECTION.
	(mergeable_string_section): New.
	(mergeable_constant_section): New.
	(default_elf_asm_named_section): Output SECTION_MERGE and
	SECTION_STRINGS flags plus SECTION_ENTSIZE entity size.
	* output.h (mergeable_string_section): New.
	(mergeable_constant_section): New.
	(SECTION_MERGE, SECTION_STRINGS, SECTION_ENTSIZE): Define.
	* toplev.c (flag_merge_constants): New.
	(f_options): Add -fmerge-constants and -fmerge-all-constants
	options.
	(toplev_main): Default to -fno-merge-constants if not optimizing.
	* flags.h (flag_merge_constants): Add extern.
	* invoke.texi (-fmerge-constants, -fmerge-all-constants): Document.
	* tm.texi (SELECT_SECTION, SELECT_RTX_SECTION): Document added third
	argument.
	* config/elfos.h (ASM_SECTION_START_OP, ASM_OUTPUT_SECTION_START):
	Define if assembler has working .subsection -1 support.
	(SELECT_RTX_SECTION, SELECT_SECTION): Add third macro argument.
	Put constant into special SHF_MERGE sections if the linker should
	attempt to merge duplicates.
	* config/ia64/sysv4.h (SELECT_RTX_SECTION, SELECT_SECTION): Add third
	macro argument.
	Put constant into special SHF_MERGE sections if the linker should
	attempt to merge duplicates.
	* config/alpha/elf.h: Likewise.
	(ASM_SECTION_START_OP, ASM_OUTPUT_SECTION_START): Define if assembler
	has working .subsection -1 support.
	* config/nextstep.h: Add third argument to SELECT_RTX_SECTION and
	SELECT_SECTION.
	* config/svr3.h: Likewise.
	* config/darwin.h: Likewise.
	* config/arm/aof.h: Likewise.
	* config/arm/linux-elf.h: Likewise.
	* config/avr/avr.h: Likewise.
	* config/c4x/c4x.h: Likewise.
	* config/d30v/d30v.h: Likewise.
	* config/i386/dgux.h: Likewise.
	* config/i386/osfrose.h: Likewise.
	* config/i386/sco5.h: Likewise.
	* config/i386/svr3gas.h: Likewise.
	* config/ia64/aix.h: Likewise.
	* config/m32r/m32r.h: Likewise.
	* config/m68k/m68k.h: Likewise.
	* config/m88k/dgux.h: Likewise.
	* config/m88k/m88k.h: Likewise.
	* config/mcore/mcore-pe.h: Likewise.
	* config/mips/mips.h: Likewise.
	* config/pa/pa.h: Likewise.
	* config/pa/pa-linux.h: Likewise.
	* config/romp/romp.h: Likewise.
	* config/rs6000/sysv4.h: Likewise.
	* config/rs6000/xcoff.h: Likewise.
	* config/s390/linux.h: Likewise.
	* config/sparc/sparc.h: Likewise.
	* config/sparc/sysv4.h: Likewise.
	* config/stormy16/stormy16.h: Likewise.
	* config/v850/v850.h: Likewise.
	* config/vax/vms.h: Likewise.
	* config/arm/arm.c (arm_elf_asm_named_section): Output SECTION_MERGE
	and SECTION_STRINGS flags plus SECTION_ENTSIZE entity size.
	* config/sparc/sparc.c (sparc_elf_asm_named_section): Use
	default_elf_asm_named_section for SHF_MERGE sections.

	* com.c (ffe_init_options): Default to -fmerge-all-constants
	if optimizing.

From-SVN: r45548

1 files changed, 14 insertions, 0 deletions

diff --git a/gcc/toplev.c b/gcc/toplev.c
index 087a13a..925f06b 100644
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -898,6 +898,11 @@ int flag_bounded_pointers = 0;
    For CHILL: defaults to off.  */
 int flag_bounds_check = 0;
 
+/* This will attempt to merge constant section constants, if 1 only
+   string constants and constants from constant pool, if 2 also constant
+   variables.  */
+int flag_merge_constants = 1;
+
 /* If one, renumber instruction UIDs to reduce the number of
    unused UIDs if there are a lot of instructions.  If greater than
    one, unconditionally renumber instruction UIDs.  */
@@ -1139,6 +1144,10 @@ lang_independent_options f_options[] =
    N_("Align all labels") },
   {"align-functions", &align_functions, 0,
    N_("Align the start of functions") },
+  {"merge-constants", &flag_merge_constants, 1,
+   N_("Attempt to merge identical constants accross compilation units") },
+  {"merge-all-constants", &flag_merge_constants, 2,
+   N_("Attempt to merge identical constants and constant variables") },
   {"check-memory-usage", &flag_check_memory_usage, 1,
    N_("Generate code to check every memory access") },
   {"prefix-function-name", &flag_prefix_function_name, 1,
@@ -4680,6 +4689,11 @@ toplev_main (argc, argv)
 	}
     }
 
+  if (!optimize)
+    {
+      flag_merge_constants = 0;
+    }
+
   if (optimize >= 1)
     {
       flag_defer_pop = 1;