[clang-tidy] Fix performance-unnecessary-value-param (#109145)
This patch essentially reverts #108674 while adding a testcase that
triggers a crash in clang-tidy.
Fixes #108963.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/performance/unnecessary-value-param-crash.cpp b/clang-tools-extra/test/clang-tidy/checkers/performance/unnecessary-value-param-crash.cpp
new file mode 100644
index 0000000..99c2fe9
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/performance/unnecessary-value-param-crash.cpp
@@ -0,0 +1,23 @@
+// RUN: %check_clang_tidy -std=c++14-or-later %s performance-unnecessary-value-param %t
+
+// The test case used to crash clang-tidy.
+// https://github.com/llvm/llvm-project/issues/108963
+
+struct A
+{
+ template<typename T> A(T&&) {}
+};
+
+struct B
+{
+ ~B();
+};
+
+struct C
+{
+ A a;
+ C(B, int i) : a(i) {}
+ // CHECK-MESSAGES: [[@LINE-1]]:6: warning: the parameter #1 is copied for each invocation but only used as a const reference; consider making it a const reference
+};
+
+C c(B(), 0);
diff --git a/clang/include/clang/Analysis/Analyses/ExprMutationAnalyzer.h b/clang/include/clang/Analysis/Analyses/ExprMutationAnalyzer.h
index b7b8485..c7a5b016 100644
--- a/clang/include/clang/Analysis/Analyses/ExprMutationAnalyzer.h
+++ b/clang/include/clang/Analysis/Analyses/ExprMutationAnalyzer.h
@@ -118,10 +118,19 @@
static FunctionParmMutationAnalyzer *
getFunctionParmMutationAnalyzer(const FunctionDecl &Func, ASTContext &Context,
ExprMutationAnalyzer::Memoized &Memorized) {
- auto [it, Inserted] = Memorized.FuncParmAnalyzer.try_emplace(&Func);
- if (Inserted)
- it->second = std::unique_ptr<FunctionParmMutationAnalyzer>(
- new FunctionParmMutationAnalyzer(Func, Context, Memorized));
+ auto it = Memorized.FuncParmAnalyzer.find(&Func);
+ if (it == Memorized.FuncParmAnalyzer.end()) {
+ // Creating a new instance of FunctionParmMutationAnalyzer below may add
+ // additional elements to FuncParmAnalyzer. If we did try_emplace before
+ // creating a new instance, the returned iterator of try_emplace could be
+ // invalidated.
+ it =
+ Memorized.FuncParmAnalyzer
+ .try_emplace(&Func, std::unique_ptr<FunctionParmMutationAnalyzer>(
+ new FunctionParmMutationAnalyzer(
+ Func, Context, Memorized)))
+ .first;
+ }
return it->getSecond().get();
}
