MIPS/BFD: Discard ineligible JALR relocations right away
authorMaciej W. Rozycki <macro@imgtec.com>
Thu, 23 Feb 2017 19:26:53 +0000 (19:26 +0000)
committerMaciej W. Rozycki <macro@imgtec.com>
Thu, 23 Feb 2017 23:45:14 +0000 (23:45 +0000)
commitc1556ecd7843912269aba283a0fd307729fa0c3a
tree1deeb56cbddecee8f8f62c6494d72e0883be1d9b
parenta567769b813b2538bebc97d689fc0739f172028e
MIPS/BFD: Discard ineligible JALR relocations right away

Discard R_MIPS_JALR and R_MICROMIPS_JALR relocations associated with
jumps that cannot be converted to an equivalent branch right away in
`mips_elf_calculate_relocation' rather than letting them through to
`mips_elf_perform_relocation'.  This includes cross-mode jumps which
need to flip the ISA bit or jumps to a misaligned location that cannot
be encoded with a branch, in addition to preemptible symbol references
already handled.

Cross-mode jumps are actually already rejected as the conversion is made
in `mips_elf_perform_relocation', so in this case this change only saves
some processing.  Jumps to a misaligned location are however converted,
with bits causing misalignment lost, making resulting code functionally
different even if the lone effect is avoiding an address error exception
with an instruction fetch at the jump destination requested.

Add test cases suitable, also including GAS verification to confirm that
the JALR relocations explicitly requested have indeed been output in the
intermediate objects used.

bfd/
* elfxx-mips.c (mips_elf_calculate_relocation) <R_MIPS_JALR>
<R_MICROMIPS_JALR>: Discard relocation if `cross_mode_jump_p'
or misaligned.

gas/
* testsuite/gas/mips/jalr4.d: New test.
* testsuite/gas/mips/jalr4-n32.d: New test.
* testsuite/gas/mips/jalr4-n64.d: New test.
* testsuite/gas/mips/jalr4.s: New test source.
* testsuite/gas/mips/mips.exp: Run the new tests.

ld/
* testsuite/ld-mips-elf/jalr4.dd: New test.
* testsuite/ld-mips-elf/mips-elf.exp: Run the new test.
bfd/ChangeLog
bfd/elfxx-mips.c
gas/ChangeLog
gas/testsuite/gas/mips/jalr4-n32.d [new file with mode: 0644]
gas/testsuite/gas/mips/jalr4-n64.d [new file with mode: 0644]
gas/testsuite/gas/mips/jalr4.d [new file with mode: 0644]
gas/testsuite/gas/mips/jalr4.s [new file with mode: 0644]
gas/testsuite/gas/mips/mips.exp
ld/ChangeLog
ld/testsuite/ld-mips-elf/jalr4.dd [new file with mode: 0644]
ld/testsuite/ld-mips-elf/mips-elf.exp