[TSan] Refine longjmp key management on Darwin

NFC.

llvm-svn: 365554

diff --git a/compiler-rt/lib/tsan/rtl/tsan_platform_mac.cc b/compiler-rt/lib/tsan/rtl/tsan_platform_mac.cc
index e43a9ec..0c2d2aa 100644 (file)
--- a/compiler-rt/lib/tsan/rtl/tsan_platform_mac.cc
+++ b/compiler-rt/lib/tsan/rtl/tsan_platform_mac.cc
@@ -238,8 +238,7 @@ void InitializePlatformEarly() {
 #endif
 }
 
-static const uptr kPthreadSetjmpXorKeySlot = 0x7;
-extern "C" uptr __tsan_darwin_setjmp_xor_key = 0;
+static uptr longjmp_xor_key = 0;
 
 void InitializePlatform() {
   DisableCoreDumperIfNecessary();
@@ -254,8 +253,9 @@ void InitializePlatform() {
 #endif
 
   if (GetMacosVersion() >= MACOS_VERSION_MOJAVE) {
-    __tsan_darwin_setjmp_xor_key =
-        (uptr)pthread_getspecific(kPthreadSetjmpXorKeySlot);
+    // Libsystem currently uses a process-global key; this might change.
+    const unsigned kTLSLongjmpXorKeySlot = 0x7;
+    longjmp_xor_key = (uptr)pthread_getspecific(kTLSLongjmpXorKeySlot);
   }
 }
 
@@ -268,7 +268,8 @@ void InitializePlatform() {
 
 uptr ExtractLongJmpSp(uptr *env) {
   uptr mangled_sp = env[LONG_JMP_SP_ENV_SLOT];
-  return mangled_sp ^ __tsan_darwin_setjmp_xor_key;
+  uptr sp = mangled_sp ^ longjmp_xor_key;
+  return sp;
 }
 
 #if !SANITIZER_GO