================
@@ -385,6 +388,185 @@ getFieldsGlobalsAndFuncs(const Stmt &S, FieldSet &Fields,
}
}
+namespace {
+
+// Visitor that builds a map from record prvalues to result objects.
+// This traverses the body of the function to be analyzed; for each result
+// object that it encounters, it propagates the storage location of the result
+// object to all record prvalues that can initialize it.
+class ResultObjectVisitor : public RecursiveASTVisitor<ResultObjectVisitor> {
+public:
+ // `ResultObjectMap` will be filled with a map from record prvalues to result
+ // object. If the function being analyzed returns a record by value,
+ // `LocForRecordReturnVal` is the location to which this record should be
+ // written; otherwise, it is null.
+ explicit ResultObjectVisitor(
+ llvm::DenseMap<const Expr *, RecordStorageLocation *> &ResultObjectMap,
+ RecordStorageLocation *LocForRecordReturnVal,
+ DataflowAnalysisContext &DACtx)
+ : ResultObjectMap(ResultObjectMap),
+ LocForRecordReturnVal(LocForRecordReturnVal), DACtx(DACtx) {}
+
+ bool shouldVisitImplicitCode() { return true; }
+
+ bool shouldVisitLambdaBody() const { return false; }
+
+ // Traverse all member and base initializers of `Ctor`. This function is not
+ // called by `RecursiveASTVisitor`; it should be called manually if we are
+ // analyzing a constructor. `ThisPointeeLoc` is the storage location that
+ // `this` points to.
+ void TraverseConstructorInits(const CXXConstructorDecl *Ctor,
+ RecordStorageLocation *ThisPointeeLoc) {
+ assert(ThisPointeeLoc != nullptr);
+ for (const CXXCtorInitializer *Init : Ctor->inits()) {
+ Expr *InitExpr = Init->getInit();
+ if (FieldDecl *Field = Init->getMember();
+ Field != nullptr && Field->getType()->isRecordType()) {
+ PropagateResultObject(InitExpr, cast<RecordStorageLocation>(
+ ThisPointeeLoc->getChild(*Field)));
+ } else if (Init->getBaseClass()) {
+ PropagateResultObject(InitExpr, ThisPointeeLoc);
+ }
+
+ // Ensure that any result objects within `InitExpr` (e.g. temporaries)
+ // are also propagated to the prvalues that initialize them.
+ TraverseStmt(InitExpr);
+
+ // If this is a `CXXDefaultInitExpr`, also propagate any result objects
+ // within the default expression.
+ if (auto *DefaultInit = dyn_cast<CXXDefaultInitExpr>(InitExpr))
+ TraverseStmt(DefaultInit->getExpr());
+ }
+ }
+
+ bool TraverseBindingDecl(BindingDecl *BD) {
+ // `RecursiveASTVisitor` doesn't traverse holding variables for
----------------
Xazax-hun wrote:
I wonder if this omission should be addressed in `RecursiveASTVisitor`. This is
a relatively new construct, so I can imagine whoever added them just forgot to
update the `RecursiveASTVisitor`.
https://github.com/llvm/llvm-project/pull/87320
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