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Have the assembler prepare for linker relaxation by default. This
means that users will be able to make use of linker relaxation without
having to adjust the assembler flags, this can make life easier when
compiling libraries.
Having this on by default in the assembler should make no difference to
the assembler code produced, however, some of the debug information will
be slightly less compressed.
A few tests needed to be updated as a result of this change as they
relied on linker relaxation support being off by default.
I've tightened up the definition of which sections can be relaxed on AVR
as part of this commit, the assembler used to think that all
non-debugging sections could be relaxed, when in reality only code
sections can be relaxed for AVR. The previous definition was not
dangerous, just over cautious. The new tighter definition allows an
extra test (gas/testsuite/gas/all/forward.d) to continue to pass.
gas/ChangeLog:
* config/tc-avr.c (struct avr_opt_s): Change link_relax to
no_link_relax, extend comment.
(enum options): Add new OPTION_NO_LINK_RELAX.
(md_longopts): Add entry for -mno-link-relax.
(md_parse_option): Handle OPTION_NO_LINK_RELAX, and update
OPTION_LINK_RELAX.
(md_begin): Initialise linkrelax from no_link_relax.
(md_show_usage): Include -mno-link-relax option.
(relaxable_section): Only allocatable code sections can be
relaxed.
* config/tc-avr.h (TC_LINKRELAX_FIXUP): Define.
gas/testsuite/ChangeLog:
* gas/all/gas.exp: Test will not pass on AVR due to linker
relaxation support.
* gas/avr/noreloc_withoutrelax.d: Add -mno-link-relax option.
* gas/avr/link-relax-elf-flag-clear.d: Likewise.
ld/testsuite/ChangeLog:
* ld/testsuite/ld-avr/relax-elf-flags-02.d: Add -mno-link-relax
option.
* ld/testsuite/ld-avr/relax-elf-flags-03.d: Likewise.
* ld/testsuite/ld-avr/relax-elf-flags-04.d: Likewise.
* ld/testsuite/ld-avr/relax-elf-flags-05.d: Likewise.
* ld/testsuite/ld-avr/relax-elf-flags-06.d: Likewise.
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The AVR target has an elf header flag to indicate if an object was
assembler ready for linker relaxation. If a partial link is performed
then it is important that the link-relax flag in the output object is
set correctly, otherwise, during the final link, we might try to perform
linker relaxation on code that was not assembled suitably.
As the link-relax elf header covers the entire object file we must be
conservative when setting the flag in the output object, so, for a
partial link, any input object that does not have the link-relax flag
set will cause the output object to also not have the link-relax flag
set.
This conservative approach could be softened in future, we only need to
disable the link relax flag if an input file is not marked link-relax
ready, and the input file contains a relaxable section. However, I've
left this optimisation for a later day.
For the final link I've overloaded the use of the link-relax elf header
flag, in a final executable, the flag now indicates if the executable
was built with linker relaxation on or not.
ld/ChangeLog:
* emultempl/avrelf.em: Add include of elf/avr.h.
(avr_finish): New function.
(LDEMUL_FINISH): Added.
ld/testsuite/ChangeLog:
* ld-avr/relax-elf-flags-01.d: New file.
* ld-avr/relax-elf-flags-02.d: New file.
* ld-avr/relax-elf-flags-03.d: New file.
* ld-avr/relax-elf-flags-04.d: New file.
* ld-avr/relax-elf-flags-05.d: New file.
* ld-avr/relax-elf-flags-06.d: New file.
* ld-avr/relax-elf-flags-07.d: New file.
* ld-avr/relax-elf-flags-08.d: New file.
* ld-avr/relax-elf-flags-a.s: New file.
* ld-avr/relax-elf-flags-b.s: New file.
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