[compiler-rt] b226894 - [sanitizer] Correct GetTls for x32

[H.J. Lu via llvm-commits]

Author: H.J. Lu
Date: 2022-05-05T13:55:19-07:00
New Revision: b226894d475b4758ed1da0c23e664b027c89634b

URL: https://github.com/llvm/llvm-project/commit/b226894d475b4758ed1da0c23e664b027c89634b
DIFF: https://github.com/llvm/llvm-project/commit/b226894d475b4758ed1da0c23e664b027c89634b.diff

LOG: [sanitizer] Correct GetTls for x32

Since x32 pointer size is 4 bytes, the self pointer offset in TCB:

struct
{
  void *tcb;
  dtv_t *dtv;
  void *self;
  ...

should be 8, not 16.

Fixes https://github.com/llvm/llvm-project/issues/55288

Differential Revision: https://reviews.llvm.org/D125025

Added: 
    

Modified: 
    compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp

Removed: 
    


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diff  --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp
index 25ad825f568bd..9bf14ef647315 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp
@@ -462,7 +462,11 @@ static void GetTls(uptr *addr, uptr *size) {
 #elif SANITIZER_GLIBC && defined(__x86_64__)
   // For aarch64 and x86-64, use an O(1) approach which requires relatively
   // precise ThreadDescriptorSize. g_tls_size was initialized in InitTlsSize.
+#  if SANITIZER_X32
+  asm("mov %%fs:8,%0" : "=r"(*addr));
+#  else
   asm("mov %%fs:16,%0" : "=r"(*addr));
+#  endif
   *size = g_tls_size;
   *addr -= *size;
   *addr += ThreadDescriptorSize();