[compiler-rt] r293586 - [compiler-rt] Don't change g_tls_size after initialization.
Tim Shen via llvm-commits
llvm-commits at lists.llvm.org
Mon Jan 30 17:53:36 PST 2017
Author: timshen
Date: Mon Jan 30 19:53:36 2017
New Revision: 293586
URL: http://llvm.org/viewvc/llvm-project?rev=293586&view=rev
Log:
[compiler-rt] Don't change g_tls_size after initialization.
Summary:
g_tls_size is not supposed to be changed after initialization. It's not
atomic, not guarded by a lock, nor thread_local. But it's read by
multiple threads.
The reason why it's mutated is mips and powerpc64 specific. We can
implement the same funcitonality without mutating g_tls_size.
I'm not sure how to write a test for this. Please advice. Thanks!
Reviewers: eugenis, kcc
Subscribers: kubamracek, dberris, llvm-commits
Differential Revision: https://reviews.llvm.org/D29236
Modified:
compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux_libcdep.cc
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux_libcdep.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux_libcdep.cc?rev=293586&r1=293585&r2=293586&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux_libcdep.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux_libcdep.cc Mon Jan 30 19:53:36 2017
@@ -270,9 +270,7 @@ static uptr TlsPreTcbSize() {
# endif
const uptr kTlsAlign = 16;
const uptr kTlsPreTcbSize =
- (ThreadDescriptorSize() + kTcbHead + kTlsAlign - 1) & ~(kTlsAlign - 1);
- InitTlsSize();
- g_tls_size = (g_tls_size + kTlsPreTcbSize + kTlsAlign -1) & ~(kTlsAlign - 1);
+ RoundUpTo(ThreadDescriptorSize() + kTcbHead, kTlsAlign);
return kTlsPreTcbSize;
}
#endif
@@ -379,6 +377,8 @@ uptr GetTlsSize() {
uptr addr, size;
GetTls(&addr, &size);
return size;
+#elif defined(__mips__) || defined(__powerpc64__)
+ return RoundUpTo(g_tls_size + TlsPreTcbSize(), 16);
#else
return g_tls_size;
#endif
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