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[Support] Fix memory leak in Timer.cpp on shutdown #159983

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Merged
merged 2 commits into from
Sep 22, 2025
Merged

[Support] Fix memory leak in Timer.cpp on shutdown #159983

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5d7d09a
[Support] Fix memory leak in Timer on shutdown
aganea Sep 21, 2025
5c0e7c9
Clarify comment.
aganea Sep 21, 2025
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23 changes: 19 additions & 4 deletions llvm/lib/Support/Timer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,7 @@ static SignpostEmitter &signposts();
static sys::SmartMutex<true> &timerLock();
static TimerGroup &defaultTimerGroup();
static Name2PairMap &namedGroupedTimers();
static bool isTimerGlobalsConstructed();

//===----------------------------------------------------------------------===//
//
Expand Down Expand Up @@ -305,14 +306,24 @@ TimerGroup::~TimerGroup() {
PrintQueuedTimers(*OutStream);
}

auto unlink = [&]() {
*Prev = Next;
if (Next)
Next->Prev = Prev;
};

// If the managed instance is already dead, it means we're in the CRT
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@MaskRay MaskRay Sep 21, 2025

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I am confused by this comment.

llvm::TimerGroup::acquireTimerGlobals() frees ManagedStatic. Is the leak due to timerLock() re-constructing the ManagedStatic?

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@aganea aganea Sep 21, 2025

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Yes, exactly.

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@aganea aganea Sep 21, 2025

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I will clarify the comment.

// destruction, so no need to lock.
if (!isTimerGlobalsConstructed()) {
unlink();
return;
}

// Remove the group from the TimerGroupList.
sys::SmartScopedLock<true> L(timerLock());
*Prev = Next;
if (Next)
Next->Prev = Prev;
unlink();
}


void TimerGroup::removeTimer(Timer &T) {
sys::SmartScopedLock<true> L(timerLock());

Expand Down Expand Up @@ -557,3 +568,7 @@ void TimerGroup::constructForStatistics() {
}

void *TimerGroup::acquireTimerGlobals() { return ManagedTimerGlobals.claim(); }

static bool isTimerGlobalsConstructed() {
return ManagedTimerGlobals.isConstructed();
}
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