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0c11728627
Fix a generic BFD issue with relocations against absolute symbols, which are installed without using any individual relocation handler provided by the backend. This causes any absolute section's addend to be lost on REL targets such as o32 MIPS, and also relocation-specific calculation adjustments are not made. As an example assembling this program: $ cat test.s .text foo: b bar b baz .set bar, 0x1234 $ as -EB -32 -o test-o32.o test.s $ as -EB -n32 -o test-n32.o test.s produces this binary code: $ objdump -dr test-o32.o test-n32.o test-o32.o: file format elf32-tradbigmips Disassembly of section .text: 00000000 <foo>: 0: 10000000 b 4 <foo+0x4> 0: R_MIPS_PC16 *ABS* 4: 00000000 nop 8: 1000ffff b 8 <foo+0x8> 8: R_MIPS_PC16 baz c: 00000000 nop test-n32.o: file format elf32-ntradbigmips Disassembly of section .text: 00000000 <foo>: 0: 10000000 b 4 <foo+0x4> 0: R_MIPS_PC16 *ABS*+0x1230 4: 00000000 nop 8: 10000000 b c <foo+0xc> 8: R_MIPS_PC16 baz-0x4 c: 00000000 nop $ where it is clearly visible in `test-o32.o', which uses REL relocations, that the absolute section's addend equivalent to the value of `bar' -- a reference to which cannot be fully resolved at the assembly time, because the reference is PC-relative -- has been lost, as has been the relocation-specific adjustment of -4, required to take into account the PC+4-relative calculation made by hardware with branches and seen in the external symbol reference to `baz' as the `ffff' addend encoded in the instruction word. In `test-n32.o', which uses RELA relocations, the absolute section's addend has been correctly retained. Give precedence then in `bfd_perform_relocation' and `bfd_install_relocation' to any individual relocation handler the backend selected may have provided, while still resorting to the generic calculation otherwise. This retains the semantics which we've had since forever or before the beginning of our repository history, and is at the very least compatible with `bfd_elf_generic_reloc' being used as the handler. Retain the `bfd_is_und_section' check unchanged at the beginning of `bfd_perform_relocation' since this does not affect the semantics of the function. The check returns the same `bfd_reloc_undefined' code the check for a null `howto' does, so swapping the two does not matter. Also the check is is mutually exclusive with the `bfd_is_abs_section' check, since a section cannot be absolute and undefined both at once, so swapping the two does not matter either. With this change applied the program quoted above now has the in-place addend correctly calculated and installed in the field being relocated: $ objdump -dr fixed-o32.o fixed-o32.o: file format elf32-tradbigmips Disassembly of section .text: 00000000 <foo>: 0: 1000048c b 1234 <bar> 0: R_MIPS_PC16 *ABS* 4: 00000000 nop 8: 1000ffff b 8 <foo+0x8> 8: R_MIPS_PC16 baz c: 00000000 nop $ Add a set of MIPS tests to cover the relevant cases, including absolute symbols with addends, and verifying that PC-relative relocations against symbols concerned resolve to the same value in the final link regardless of whether the REL or the RELA relocation form is used. Exclude linker tests though which would overflow the in-place addend on REL targets and use them as dump patterns for RELA targets only. bfd/ * reloc.c (bfd_perform_relocation): Try the `howto' handler first with relocations against absolute symbols. (bfd_install_relocation): Likewise. gas/ * testsuite/gas/mips/mips16-branch-absolute.d: Update patterns. * testsuite/gas/mips/branch-absolute.d: New test. * testsuite/gas/mips/branch-absolute-n32.d: New test. * testsuite/gas/mips/branch-absolute-n64.d: New test. * testsuite/gas/mips/branch-absolute-addend-n32.d: New test. * testsuite/gas/mips/branch-absolute-addend-n64.d: New test. * testsuite/gas/mips/mips16-branch-absolute-n32.d: New test. * testsuite/gas/mips/mips16-branch-absolute-n64.d: New test. * testsuite/gas/mips/mips16-branch-absolute-addend-n32.d: New test. * testsuite/gas/mips/mips16-branch-absolute-addend-n64.d: New test. * testsuite/gas/mips/micromips-branch-absolute.d: New test. * testsuite/gas/mips/micromips-branch-absolute-n32.d: New test. * testsuite/gas/mips/micromips-branch-absolute-n64.d: New test. * testsuite/gas/mips/micromips-branch-absolute-addend-n32.d: New test. * testsuite/gas/mips/micromips-branch-absolute-addend-n64.d: New test. * testsuite/gas/mips/branch-absolute.s: New test source. * testsuite/gas/mips/branch-absolute-addend.s: New test source. * testsuite/gas/mips/mips16-branch-absolute-addend.s: New test source. * testsuite/gas/mips/micromips-branch-absolute.s: New test source. * testsuite/gas/mips/micromips-branch-absolute-addend.s: New test source. * testsuite/gas/mips/mips.exp: Run the new tests. ld/ * testsuite/ld-mips-elf/branch-absolute.d: New test. * testsuite/ld-mips-elf/branch-absolute-n32.d: New test. * testsuite/ld-mips-elf/branch-absolute-n64.d: New test. * testsuite/ld-mips-elf/branch-absolute-addend.d: New test. * testsuite/ld-mips-elf/branch-absolute-addend-n32.d: New test. * testsuite/ld-mips-elf/branch-absolute-addend-n64.d: New test. * testsuite/ld-mips-elf/micromips-branch-absolute.d: New test. * testsuite/ld-mips-elf/micromips-branch-absolute-n32.d: New test. * testsuite/ld-mips-elf/micromips-branch-absolute-n64.d: New test. * testsuite/ld-mips-elf/micromips-branch-absolute-addend.d: New test. * testsuite/ld-mips-elf/micromips-branch-absolute-addend-n32.d: New test. * testsuite/ld-mips-elf/micromips-branch-absolute-addend-n64.d: New test. * testsuite/ld-mips-elf/mips-elf.exp: Run the new tests, except from `branch-absolute-addend' and `micromips-branch-absolute-addend', referred indirectly only.
22 lines
677 B
Makefile
22 lines
677 B
Makefile
#objdump: -dr --prefix-addresses --show-raw-insn
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#name: MIPS link branch to absolute expression
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#source: ../../../gas/testsuite/gas/mips/branch-absolute.s
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#as: -EB -32
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#ld: -EB -Ttext 0 -e foo
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.*: +file format .*mips.*
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Disassembly of section \.text:
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\.\.\.
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[0-9a-f]+ <[^>]*> 1000008c b 0+001234 <bar>
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[0-9a-f]+ <[^>]*> 00000000 nop
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[0-9a-f]+ <[^>]*> 0411008a bal 0+001234 <bar>
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[0-9a-f]+ <[^>]*> 00000000 nop
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[0-9a-f]+ <[^>]*> 04100088 bltzal zero,0+001234 <bar>
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[0-9a-f]+ <[^>]*> 00000000 nop
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[0-9a-f]+ <[^>]*> 10400086 beqz v0,0+001234 <bar>
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[0-9a-f]+ <[^>]*> 00000000 nop
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[0-9a-f]+ <[^>]*> 14400084 bnez v0,0+001234 <bar>
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[0-9a-f]+ <[^>]*> 00000000 nop
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\.\.\.
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