[llvm-dev] BLX relocation regression on Thumb2 bot

[Renato Golin via llvm-dev]

FYI, the bot now built successfully, which is worrying. It's also
elusive to my bisect attempts so far.

Unless there was a fix that I failed to see, we could be dealing with
a self-hosting heisenbug... :S

--renato

On 18 May 2016 at 12:12, Renato Golin <renato.golin at linaro.org> wrote:
> Hi Tim,
>
> You seem to be working around BLX support on ARM, and this linker
> error has cropped up on our buildbot:
>
> http://lab.llvm.org:8011/builders/clang-cmake-thumbv7-a15-full-sh/builds/3526
>
> llvm/tools/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp:
>
> (.text._ZN5clang4ento24ProgramStatePartialTraitIN4llvm12ImmutableMapIPKNS0_7SymExprEN12_GLOBAL__N_111ReallocPairENS2_16ImutKeyValueInfoIS6_S8_EEEEE13DeleteContextEPv+0x88):
>
> relocation truncated to fit: R_ARM_THM_JUMP24 against symbol `operator
> delete(void*)@@GLIBCXX_3.4' defined in .text section in
> /usr/lib/gcc/arm-linux-gnueabihf/4.8/libstdc++.so
>
> If I read the AAELF ABI document correctly, that relocation is used
> when the linker is building a veneer for under-reaching branches,
> which seems to be one of your changes (269101), though that was
> supposed to be MachO only.
>
> Do you have any ideas on the issue?
>
> cheers,
> -renato
>
> PS: I'm bisecting it right now, but it's self hosted + compiler-rt, so
> it will take a while. Also, I fear whatever I find will be just
> uncovering the problem, not causing it.