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cmd/link: bad relocations on darwin #7280

dvyukov opened this issue Feb 7, 2014 · 4 comments

cmd/link: bad relocations on darwin #7280

dvyukov opened this issue Feb 7, 2014 · 4 comments


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@dvyukov dvyukov commented Feb 7, 2014

parent: 19024:e2f19c96b7e2 tip, darwin/amd64

$ hg clpatch 55100044
$ ./make.bash
$ go run -race pkg/runtime/race/testdata/cgo_test_main.go

crashes with random failures depending on revision number.
The root cause is that runtime.racefuncenter calls to a random address instead of

    CALL    __tsan_func_enter(SB)
is replaced with:
    MOVQ    $__tsan_func_enter(SB), AX
    CALL    AX
then it works correctly.

The difference that I see between these versions is:
machoreloc1 rs->name=__tsan_read r->type=120
machoreloc1 rs->name=__tsan_read r->type=247

120 refers to D_ADDR and works, 247 refers to D_PCREL and does not work.
Not sure where to dig further.
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@dvyukov dvyukov commented Feb 10, 2014

Comment 1:

Russ, can you help with this? It seems to be your code.
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@rsc rsc commented Feb 24, 2014

Comment 2:

My suggestion is to keep using that workaround for now.
We can look at this for Go 1.4, but I don't want to make linker changes now, and you've
got a way to make it work.

Labels changed: added release-go1.4, removed release-go1.3.

Owner changed to ---.

Status changed to Accepted.

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@rsc rsc commented Sep 15, 2014

Comment 3:

Labels changed: added release-go1.5, removed release-go1.4.

@bradfitz bradfitz modified the milestone: Go1.5 Dec 16, 2014
@bradfitz bradfitz removed the release-go1.5 label Dec 16, 2014
@rsc rsc added OS-Darwin and removed os-macosx labels Apr 10, 2015
@rsc rsc changed the title cmd/ld: bad relocations on darwin cmd/link: bad relocations on darwin Jun 8, 2015
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@rsc rsc commented Jun 29, 2015

It looks to me like later refactoring of the code has removed even the possibility of writing the alternate form, so there's not much left to do here. I don't know why the PC-relative instruction failed, but it has to do with relocations and linking and probably magic indirections, so it's not surprising there is a detail wrong somewhere.

@rsc rsc closed this Jun 29, 2015
@golang golang locked and limited conversation to collaborators Jun 28, 2016
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4 participants