Senthil Kumar Selvaraj writes:
> Hi,
>
> This patch fixes a problem with fmerge-all-constants and the progmem
> attribute - on trunk, the below testcase errors out with a section
> conflict error.
>
> When avr_asm_select_section renames .rodata.xyz section to
> .progmem.xyz and calls get_section, it passes in the same flags in
> sect. If the flags include SECTION_DECLARED, get_section barfs with a
> section conflict error - the section flag comparison logic strips off
> SECTION_DECLARED from existing section flags before comparing it with
> the new incoming flags.
>
> With -fmerge-all-constants, default_elf_select_section always returns
> .rodata.strx.x. varasm switches to that section when writing out the
> non progmem string literal, and that sets SECTION_DECLARED. The first
> call to get_section with the section name transformed to
> .progmem.data.strx.x then includes SECTION_DECLARED, but because this
> is a new section, the section flag conflict logic doesn't kick in. The
> second call to get_section, again including SECTION_DECLARED, triggers
> the section flag conflict logic and causes the error.
>
> Stripping off SECTION_DECLARED before calling get_section fixes the
> problem - the flag is supposed to be set by switch_section anyway.
>
> Reg testing showed no new regressions. Ok for trunk and backport to 6.x?
>
> Regards
> Senthil
>
Added missing description in Changelog entry.
gcc/testsuite/ChangeLog:
2016-07-05 Senthil Kumar Selvaraj <senthil_kumar.selva...@atmel.com>
PR target/50739
* gcc.target/avr/pr50739.c: New test.
gcc/ChangeLog:
2016-07-05 Senthil Kumar Selvaraj <senthil_kumar.selva...@atmel.com>
PR target/50739
* config/avr/avr.c (avr_asm_select_section): Strip off
SECTION_DECLARED from flags when calling get_section.
Regards
Senthil
>
> gcc/testsuite/ChangeLog:
>
> 2016-07-05 Senthil Kumar Selvaraj <senthil_kumar.selva...@atmel.com>
>
> PR target/50739
> * gcc.target/avr/pr50739.c: New test.
>
>
> gcc/ChangeLog:
>
> 2016-07-05 Senthil Kumar Selvaraj <senthil_kumar.selva...@atmel.com>
>
> PR target/50739
> * config/avr/avr.c (avr_asm_select_section):
>
>
> diff --git gcc/config/avr/avr.c gcc/config/avr/avr.c
> index 18ed766..9b7b392 100644
> --- gcc/config/avr/avr.c
> +++ gcc/config/avr/avr.c
> @@ -9641,7 +9641,7 @@ avr_asm_select_section (tree decl, int reloc, unsigned
> HOST_WIDE_INT align)
> {
> const char *sname = ACONCAT ((new_prefix,
> name + strlen (old_prefix),
> NULL));
> - return get_section (sname, sect->common.flags,
> sect->named.decl);
> + return get_section (sname, sect->common.flags &
> ~SECTION_DECLARED, sect->named.decl);
> }
> }
>
> diff --git gcc/testsuite/gcc.target/avr/pr50739.c
> gcc/testsuite/gcc.target/avr/pr50739.c
> new file mode 100644
> index 0000000..a6850b7
> --- /dev/null
> +++ gcc/testsuite/gcc.target/avr/pr50739.c
> @@ -0,0 +1,7 @@
> +/* { dg-do compile } */
> +/* { dg-options "-fmerge-all-constants" } */
> +
> +char *ca = "123";
> +
> +const char a[] __attribute__((__progmem__))= "a";
> +const char b[] __attribute__((__progmem__))= "b";
