re PR c++/16276 ([3.4 only] G++ generates local references to linkonce sections)

re PR c++/16276 ([3.4 only] G++ generates local references to linkonce sections)

        PR c++/16276
        * output.h (default_function_rodata_section,
	default_no_function_rodata_section): New prototypes.
	* target.h (struct gcc_target): Add asm_out.function_rodata_section.
	* target-def.h (TARGET_ASM_FUNCTION_RODATA_SECTION): Define.
	(TARGET_ASM_OUT): Add it.
        * varasm.c (default_function_rodata_section,
	default_no_function_rodata_section): New functions.
        * final.c (final_scan_insn): Call
	targetm.asm_out.function_rodata_section instead of
	readonly_data_section.
	* config/darwin.h (TARGET_ASM_FUNCTION_RODATA_SECTION): Define.
	* config/mcore/mcore.c (TARGET_ASM_FUNCTION_RODATA_SECTION): Likewise.
	* config/ip2k/ip2k.c (TARGET_ASM_FUNCTION_RODATA_SECTION): Likewise.
	* config/rs6000/xcoff.h (TARGET_ASM_FUNCTION_RODATA_SECTION):
	Likewise.
	* config/alpha/alpha.c (TARGET_ASM_FUNCTION_RODATA_SECTION): Likewise.
	* config/i386/cygming.h (TARGET_ASM_FUNCTION_RODATA_SECTION):
	Likewise.
	* config/i386/i386-interix.h (TARGET_ASM_FUNCTION_RODATA_SECTION):
	Likewise.
	* config/arm/pe.h (TARGET_ASM_FUNCTION_RODATA_SECTION): Likewise.
	* config/avr/avr.c (TARGET_ASM_FUNCTION_RODATA_SECTION): Likewise.
	* doc/tm.texi (TARGET_ASM_FUNCTION_RODATA_SECTION): Document.

        * g++.old-deja/g++.other/comdat4.C: New test.
        * g++.old-deja/g++.other/comdat4-aux.cc: New.

From-SVN: r85873