On Wed, 24 Oct 2012, Paulo Matos wrote:
> I gave it a go with TEXT_SECTION_ASM_OP.
Given what you've found, maybe other macros are easier to convert....
> I started by changing crtstuff.c to use __LIBGCC_TEXT_SECTION_ASM_OP__
> instead of TEXT_SECTION_ASM_OP. I noticed crtstuff.c is not compiled
> with -fbuilding-libgcc so I added the flags to CRTSTUFF_T_CFLAGS in my
> makefile fragment.
That would seem to make sense anyway.
> /* For libgcc crtstuff.c. */
> #ifdef TEXT_SECTION_ASM_OP
> builtin_define_with_value ("__LIBGCC_TEXT_SECTION_ASM_OP__",
> TEXT_SECTION_ASM_OP, true);
> #else
> /* Is text_section always an unnamed section? */
> builtin_define_with_value ("__LIBGCC_TEXT_SECTION_ASM_OP__",
> (const char *)text_section->unnamed.data,
> true);
> #endif
> }
>
> The reason for the ifdef is because the docs allow the backend to define
> either TEXT_SECTION_ASM_OP or the text_section directly in
> TARGET_ASM_INIT_SECTIONS.
> Therefore if we don't have TEXT_SECTION_ASM_OP we need to grab the text
> string from text_section. I assumed text_section was defined in
> TARGET_ASM_INIT_SECTIONS with an unnamed section (that's how I did it)
> but I am unsure if this is a general assumption.
I don't like this #else. Presumably the libgcc code already works if
TEXT_SECTION_ASM_OP isn't defined at all. So the equivalent is simply not
to define __LIBGCC_TEXT_SECTION_ASM_OP__ in that case, rather than
synthesizing a definition from other information.
If however you want to synthesize a definition, then I think
TEXT_SECTION_ASM_OP should be converted to a target hook (at least to the
extent of targhooks.c being the only place testing it, if it remains at
all), so that the logic generating predefined macros is unconditional.
> #define __LIBGCC_TEXT_SECTION_ASM_OP__ " .section .text, "axU""
So you should teach builtin_define_with_value to generate proper escapes
when producing a string.
--
Joseph S. Myers
jos...@codesourcery.com
