[clang] d7f32f1 - [clang] Fix some static initialization race-conditions (#181367)
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cfe-commits at lists.llvm.org
Tue Feb 17 01:53:47 PST 2026
Author: Richard Dzenis
Date: 2026-02-17T11:53:42+02:00
New Revision: d7f32f1fbf83da2faa4acdcaf2a4d4885a2d068c
URL: https://github.com/llvm/llvm-project/commit/d7f32f1fbf83da2faa4acdcaf2a4d4885a2d068c
DIFF: https://github.com/llvm/llvm-project/commit/d7f32f1fbf83da2faa4acdcaf2a4d4885a2d068c.diff
LOG: [clang] Fix some static initialization race-conditions (#181367)
- clang/StaticAnalyzer: fix static init in findKnownClass. Prior to this patch two threads running in findKnownClass could result in a race condition.
- clang/Stmt: fix StmtClassNameTable array initialization: prior to this patch there was a race condition when two threads check`if(Initialized)` at the same time.
- clang/ParsedAttrInfo: fix race condition in getAttributePluginInstances. Prior to this patch two threads could enter `if(empty())` check.
- clang/CodeGen: correctly restore diagnostic handler in HandleTranslationUnit. Prior to this patch an early exit from HandleTranslationUnit could result in not restoring previous diagnostic handler.
Added:
Modified:
clang/lib/AST/Stmt.cpp
clang/lib/Basic/ParsedAttrInfo.cpp
clang/lib/CodeGen/CodeGenAction.cpp
clang/lib/StaticAnalyzer/Checkers/BasicObjCFoundationChecks.cpp
Removed:
################################################################################
diff --git a/clang/lib/AST/Stmt.cpp b/clang/lib/AST/Stmt.cpp
index 5b745dd3c43f5..14e6ea8d1d10e 100644
--- a/clang/lib/AST/Stmt.cpp
+++ b/clang/lib/AST/Stmt.cpp
@@ -40,6 +40,7 @@
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
+#include <array>
#include <cassert>
#include <cstring>
#include <optional>
@@ -57,25 +58,23 @@ using namespace clang;
#define ABSTRACT_STMT(STMT)
#include "clang/AST/StmtNodes.inc"
-static struct StmtClassNameTable {
+struct StmtClassNameTable {
const char *Name;
unsigned Counter;
unsigned Size;
-} StmtClassInfo[Stmt::lastStmtConstant+1];
+};
static StmtClassNameTable &getStmtInfoTableEntry(Stmt::StmtClass E) {
- static bool Initialized = false;
- if (Initialized)
- return StmtClassInfo[E];
-
- // Initialize the table on the first use.
- Initialized = true;
+ static std::array<StmtClassNameTable, Stmt::lastStmtConstant + 1>
+ StmtClassInfo = [] {
+ std::array<StmtClassNameTable, Stmt::lastStmtConstant + 1> Table;
#define ABSTRACT_STMT(STMT)
-#define STMT(CLASS, PARENT) \
- StmtClassInfo[(unsigned)Stmt::CLASS##Class].Name = #CLASS; \
- StmtClassInfo[(unsigned)Stmt::CLASS##Class].Size = sizeof(CLASS);
+#define STMT(CLASS, PARENT) \
+ Table[static_cast<unsigned>(Stmt::CLASS##Class)].Name = #CLASS; \
+ Table[static_cast<unsigned>(Stmt::CLASS##Class)].Size = sizeof(CLASS);
#include "clang/AST/StmtNodes.inc"
-
+ return Table;
+ }();
return StmtClassInfo[E];
}
@@ -85,7 +84,7 @@ void *Stmt::operator new(size_t bytes, const ASTContext& C,
}
const char *Stmt::getStmtClassName() const {
- return getStmtInfoTableEntry((StmtClass) StmtBits.sClass).Name;
+ return getStmtInfoTableEntry(static_cast<StmtClass>(StmtBits.sClass)).Name;
}
// Check that no statement / expression class is polymorphic. LLVM style RTTI
@@ -113,19 +112,25 @@ void Stmt::PrintStats() {
unsigned sum = 0;
llvm::errs() << "\n*** Stmt/Expr Stats:\n";
for (int i = 0; i != Stmt::lastStmtConstant+1; i++) {
- if (StmtClassInfo[i].Name == nullptr) continue;
- sum += StmtClassInfo[i].Counter;
+ const StmtClassNameTable &Entry =
+ getStmtInfoTableEntry(static_cast<Stmt::StmtClass>(i));
+ if (Entry.Name == nullptr)
+ continue;
+ sum += Entry.Counter;
}
llvm::errs() << " " << sum << " stmts/exprs total.\n";
sum = 0;
for (int i = 0; i != Stmt::lastStmtConstant+1; i++) {
- if (StmtClassInfo[i].Name == nullptr) continue;
- if (StmtClassInfo[i].Counter == 0) continue;
- llvm::errs() << " " << StmtClassInfo[i].Counter << " "
- << StmtClassInfo[i].Name << ", " << StmtClassInfo[i].Size
- << " each (" << StmtClassInfo[i].Counter*StmtClassInfo[i].Size
+ const StmtClassNameTable &Entry =
+ getStmtInfoTableEntry(static_cast<Stmt::StmtClass>(i));
+ if (Entry.Name == nullptr)
+ continue;
+ if (Entry.Counter == 0)
+ continue;
+ llvm::errs() << " " << Entry.Counter << " " << Entry.Name << ", "
+ << Entry.Size << " each (" << Entry.Counter * Entry.Size
<< " bytes)\n";
- sum += StmtClassInfo[i].Counter*StmtClassInfo[i].Size;
+ sum += Entry.Counter * Entry.Size;
}
llvm::errs() << "Total bytes = " << sum << "\n";
diff --git a/clang/lib/Basic/ParsedAttrInfo.cpp b/clang/lib/Basic/ParsedAttrInfo.cpp
index 16fa314b642b9..d5b17b34b6e3a 100644
--- a/clang/lib/Basic/ParsedAttrInfo.cpp
+++ b/clang/lib/Basic/ParsedAttrInfo.cpp
@@ -20,13 +20,16 @@ using namespace clang;
LLVM_INSTANTIATE_REGISTRY(ParsedAttrInfoRegistry)
+static std::list<std::unique_ptr<ParsedAttrInfo>> instantiateEntries() {
+ std::list<std::unique_ptr<ParsedAttrInfo>> Instances;
+ for (const auto &It : ParsedAttrInfoRegistry::entries())
+ Instances.emplace_back(It.instantiate());
+ return Instances;
+}
+
const std::list<std::unique_ptr<ParsedAttrInfo>> &
clang::getAttributePluginInstances() {
- static llvm::ManagedStatic<std::list<std::unique_ptr<ParsedAttrInfo>>>
- PluginAttrInstances;
- if (PluginAttrInstances->empty())
- for (const auto &It : ParsedAttrInfoRegistry::entries())
- PluginAttrInstances->emplace_back(It.instantiate());
-
- return *PluginAttrInstances;
+ static std::list<std::unique_ptr<ParsedAttrInfo>> Instances =
+ instantiateEntries();
+ return Instances;
}
diff --git a/clang/lib/CodeGen/CodeGenAction.cpp b/clang/lib/CodeGen/CodeGenAction.cpp
index a5ef4ac9d361d..29dcabd1b0971 100644
--- a/clang/lib/CodeGen/CodeGenAction.cpp
+++ b/clang/lib/CodeGen/CodeGenAction.cpp
@@ -248,6 +248,8 @@ void BackendConsumer::HandleTranslationUnit(ASTContext &C) {
LLVMContext &Ctx = getModule()->getContext();
std::unique_ptr<DiagnosticHandler> OldDiagnosticHandler =
Ctx.getDiagnosticHandler();
+ llvm::scope_exit RestoreDiagnosticHandler(
+ [&]() { Ctx.setDiagnosticHandler(std::move(OldDiagnosticHandler)); });
Ctx.setDiagnosticHandler(std::make_unique<ClangDiagnosticHandler>(
CodeGenOpts, this));
@@ -311,8 +313,6 @@ void BackendConsumer::HandleTranslationUnit(ASTContext &C) {
C.getTargetInfo().getDataLayoutString(), getModule(),
Action, FS, std::move(AsmOutStream), this);
- Ctx.setDiagnosticHandler(std::move(OldDiagnosticHandler));
-
if (OptRecordFile)
OptRecordFile->keep();
}
diff --git a/clang/lib/StaticAnalyzer/Checkers/BasicObjCFoundationChecks.cpp b/clang/lib/StaticAnalyzer/Checkers/BasicObjCFoundationChecks.cpp
index e682c4ef80896..f226f80aa441f 100644
--- a/clang/lib/StaticAnalyzer/Checkers/BasicObjCFoundationChecks.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/BasicObjCFoundationChecks.cpp
@@ -70,16 +70,12 @@ enum FoundationClass {
static FoundationClass findKnownClass(const ObjCInterfaceDecl *ID,
bool IncludeSuperclasses = true) {
- static llvm::StringMap<FoundationClass> Classes;
- if (Classes.empty()) {
- Classes["NSArray"] = FC_NSArray;
- Classes["NSDictionary"] = FC_NSDictionary;
- Classes["NSEnumerator"] = FC_NSEnumerator;
- Classes["NSNull"] = FC_NSNull;
- Classes["NSOrderedSet"] = FC_NSOrderedSet;
- Classes["NSSet"] = FC_NSSet;
- Classes["NSString"] = FC_NSString;
- }
+ static const llvm::StringMap<FoundationClass> Classes{
+ {"NSArray", FC_NSArray}, {"NSDictionary", FC_NSDictionary},
+ {"NSEnumerator", FC_NSEnumerator}, {"NSNull", FC_NSNull},
+ {"NSOrderedSet", FC_NSOrderedSet}, {"NSSet", FC_NSSet},
+ {"NSString", FC_NSString},
+ };
// FIXME: Should we cache this at all?
FoundationClass result = Classes.lookup(ID->getIdentifier()->getName());
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