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Make gCrashRecoveryEnabled thread local 

If context is enabled/disabled and queried concurrently then this
results in a data race/TSAN failure with RunSafely (where boolean
variable was not locked).

There doesn't seem to be a reasonable way to enable threads that enable
and disable recovery in parallel (without also keeping
gCrashRecoveryEnabled's lock held during Fn execution which seems
undesirable). This makes enable checking if enabled thread local and
consistent with other thread local usage of crash context here.

Differential Revision: https://reviews.llvm.org/D93907
This commit is contained in:
Jacques Pienaar 2021-02-10 12:44:18 -08:00
parent 1cb47a063e
commit 5e77ea04f2
1 changed files with 1 additions and 5 deletions
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6
llvm/lib/Support/CrashRecoveryContext.cpp
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@ -84,8 +84,7 @@ public:
};
} // namespace
static ManagedStatic<std::mutex> gCrashRecoveryContextMutex;
static bool gCrashRecoveryEnabled = false;
static LLVM_THREAD_LOCAL bool gCrashRecoveryEnabled = false;
static ManagedStatic<sys::ThreadLocal<const CrashRecoveryContext>>
tlIsRecoveringFromCrash;
@ -136,8 +135,6 @@ CrashRecoveryContext *CrashRecoveryContext::GetCurrent() {
}
void CrashRecoveryContext::Enable() {
std::lock_guard<std::mutex> L(*gCrashRecoveryContextMutex);
// FIXME: Shouldn't this be a refcount or something?
if (gCrashRecoveryEnabled)
return;
gCrashRecoveryEnabled = true;
@ -145,7 +142,6 @@ void CrashRecoveryContext::Enable() {
}
void CrashRecoveryContext::Disable() {
std::lock_guard<std::mutex> L(*gCrashRecoveryContextMutex);
if (!gCrashRecoveryEnabled)
return;
gCrashRecoveryEnabled = false;