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author | Fangrui Song <maskray@google.com> | 2019-07-11 10:10:09 +0000 |
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committer | Fangrui Song <maskray@google.com> | 2019-07-11 10:10:09 +0000 |
commit | f9ca13cb5f05f2a1acce223e794444078584ef0d (patch) | |
tree | 402515c903d7548289f99535627d2571d1cf9b1a /lldb/packages/Python/lldbsuite/test/functionalities/recursion/main.cpp | |
parent | 63f5235978568421adecba44af88cca0a13019c2 (diff) | |
download | bcm5719-llvm-f9ca13cb5f05f2a1acce223e794444078584ef0d.tar.gz bcm5719-llvm-f9ca13cb5f05f2a1acce223e794444078584ef0d.zip |
[X86] -fno-plt: use GOT __tls_get_addr only if GOTPCRELX is enabled
Summary:
As of binutils 2.32, ld has a bogus TLS relaxation error when the GD/LD
code sequence using R_X86_64_GOTPCREL (instead of R_X86_64_GOTPCRELX) is
attempted to be relaxed to IE/LE (binutils PR24784). gold and lld are good.
In gcc/config/i386/i386.md, there is a configure-time check of as/ld
support and the GOT relaxation will not be used if as/ld doesn't support
it:
if (flag_plt || !HAVE_AS_IX86_TLS_GET_ADDR_GOT)
return "call\t%P2";
return "call\t{*%p2@GOT(%1)|[DWORD PTR %p2@GOT[%1]]}";
In clang, -DENABLE_X86_RELAX_RELOCATIONS=OFF is the default. The ld.bfd
bogus error can be reproduced with:
thread_local int a;
int main() { return a; }
clang -fno-plt -fpic a.cc -fuse-ld=bfd
GOTPCRELX gained relative good support in 2016, which is considered
relatively new. It is even difficult to conditionally default to
-DENABLE_X86_RELAX_RELOCATIONS=ON due to cross compilation reasons. So
work around the ld.bfd bug by only using GOT when GOTPCRELX is enabled.
Reviewers: dalias, hjl.tools, nikic, rnk
Reviewed By: nikic
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64304
llvm-svn: 365752
Diffstat (limited to 'lldb/packages/Python/lldbsuite/test/functionalities/recursion/main.cpp')
0 files changed, 0 insertions, 0 deletions