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[BOLT] Fix data race in MCPlusBuilder::getOrCreateAnnotationIndex #67004

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Merged
merged 3 commits into from
Sep 21, 2023
Merged

[BOLT] Fix data race in MCPlusBuilder::getOrCreateAnnotationIndex #67004

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3987fd2
[BOLT] Fix data race in MCPlusBuilder::getOrCreateAnnotationIndex
kbeyls Sep 21, 2023
faad7c7
Update bolt/include/bolt/Core/MCPlusBuilder.h
kbeyls Sep 21, 2023
7c31675
Another minor improvement to coding style.
kbeyls Sep 21, 2023
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12 changes: 9 additions & 3 deletions bolt/include/bolt/Core/MCPlusBuilder.h
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@
#include "llvm/Support/Allocator.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/RWMutex.h"
#include <cassert>
#include <cstdint>
#include <map>
Expand Down Expand Up @@ -166,6 +167,10 @@ class MCPlusBuilder {
/// Names of non-standard annotations.
SmallVector<std::string, 8> AnnotationNames;

/// A mutex that is used to control parallel accesses to
/// AnnotationNameIndexMap and AnnotationsNames.
mutable llvm::sys::RWMutex AnnotationNameMutex;

/// Allocate the TailCall annotation value. Clients of the target-specific
/// MCPlusBuilder classes must use convert/lower/create* interfaces instead.
void setTailCall(MCInst &Inst);
Expand Down Expand Up @@ -1775,6 +1780,7 @@ class MCPlusBuilder {

/// Return annotation index matching the \p Name.
std::optional<unsigned> getAnnotationIndex(StringRef Name) const {
std::shared_lock<llvm::sys::RWMutex> Lock(AnnotationNameMutex);
auto AI = AnnotationNameIndexMap.find(Name);
if (AI != AnnotationNameIndexMap.end())
return AI->second;
Expand All @@ -1784,10 +1790,10 @@ class MCPlusBuilder {
/// Return annotation index matching the \p Name. Create a new index if the
/// \p Name wasn't registered previously.
unsigned getOrCreateAnnotationIndex(StringRef Name) {
auto AI = AnnotationNameIndexMap.find(Name);
if (AI != AnnotationNameIndexMap.end())
return AI->second;
if (std::optional<unsigned> Index = getAnnotationIndex(Name))
return *Index;

std::unique_lock<llvm::sys::RWMutex> Lock(AnnotationNameMutex);
const unsigned Index =
AnnotationNameIndexMap.size() + MCPlus::MCAnnotation::kGeneric;
AnnotationNameIndexMap.insert(std::make_pair(Name, Index));
Expand Down