[PATCH] More aggressive --gc-sections

[Eric Botcazou]

Hi,

This is the minimal set of patches needed in order to make --gc-sections 
works for dynamically linked Ada programs using DWARF-2 EH on x86/Linux.

For a description of the mechanism, see:
http://gcc.gnu.org/ml/gcc/2004-03/msg00506.html

The GCC part was bootstrapped/regtested on mainline, the binutils part was 
tested on mainline, with no new regressions.  I ran the ACATS and libstdc++ 
testsuites with -function-sections -fdata-sections -Wl,--gc-sections too.

I don't expect these patches to be accepted, rather to serve as a starting 
point for the discussion.  What do you think about the approach?  What 
criteria should the patches meet to be accepted both in GCC and binutils?

Thanks in advance.


GCC:

	* except.h (output_function_exception_table): New prototype.
	* output.h (default_exception_section): New prototype.
	* target.h (struct gcc_target) <exception_section>: New prototype.
	* except.c (PTR_SIZE): New macro.
	(default_exception_section): New prototype.
	If named sections are supported and flag_function_sections is set,
	use a function-specific section.
	(output_function_exception_table): New prototype.
	Adjust call to targetm.asm_out.exception_section.  Keep track of the LDSA
	label.  If flag_function_sections is set, emit a reference to the LDSA
	label in the function section.
	* passes.c (rest_of_handle_final): Adjust calls to
	output_function_exception_table.
	* Makefile.in (LIBGCC2_CFLAGS): Add -ffunction-sections -fdata-sections.
	* ada/Makefile.in (GNATLIBCFLAGS): Likewise.
	* ada/Make-lang.in (GNATLIBCFLAGS): Likewise.

BFD:

	* elflink.h (elf_gc_mark_dynamic_ref_symbol): New function.
	(elf_gc_sections): Do not gracefully fail if dynamic sections have
	been created.  Instead call elf_gc_mark_dynamic_ref_symbol to
	mark dynamically referenced symbols.  Do not mark the whole graph
	rooted at .eh_frame, only the section proper.

LD:

	* scripttempl/elf.sc (.text): Add KEEP for .text.*personality*.
	(.data): Add KEEP for .gnu.linkonce.d.*personality*.
	(.gcc_except_table): Add KEEP for self and accept .gcc_except_table.*.


-- 
Eric Botcazou
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