[Clang] Fixes instantiation of OpaqueValueExprs (Bug llvm#45964)

ricejasonf · Aug 18, 2021 · ac9d328 · ac9d328
1 parent fed4134
commit ac9d328
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Showing 2 changed files with 20 additions and 4 deletions.
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
@@ -8595,9 +8595,13 @@ ExprResult InitializationSequence::Perform(Sema &S,
 
     case SK_ArrayLoopIndex: {
       Expr *Cur = CurInit.get();
-      Expr *BaseExpr = new (S.Context)
-          OpaqueValueExpr(Cur->getExprLoc(), Cur->getType(),
-                          Cur->getValueKind(), Cur->getObjectKind(), Cur);
+      // prevent nested OpaqueValueExprs
+      Expr *BaseExpr = dyn_cast<OpaqueValueExpr>(Cur);
+      if (!BaseExpr) {
+        BaseExpr = new (S.Context)
+            OpaqueValueExpr(Cur->getExprLoc(), Cur->getType(),
+                            Cur->getValueKind(), Cur->getObjectKind(), Cur);
+      }
       Expr *IndexExpr =
           new (S.Context) ArrayInitIndexExpr(S.Context.getSizeType());
       CurInit = S.CreateBuiltinArraySubscriptExpr(

diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
@@ -10201,7 +10201,19 @@ ExprResult
 TreeTransform<Derived>::TransformOpaqueValueExpr(OpaqueValueExpr *E) {
   assert((!E->getSourceExpr() || getDerived().AlreadyTransformed(E->getType())) &&
          "opaque value expression requires transformation");
-  return E;
+
+  // Note that SourceExpr can be nullptr
+  ExprResult SourceExpr = TransformExpr(E->getSourceExpr());
+  if (SourceExpr.isInvalid()) return ExprError();
+  if (SourceExpr.get() == E->getSourceExpr() && !getDerived().AlwaysRebuild()) {
+    return E;
+  }
+
+  OpaqueValueExpr *New =
+    new (SemaRef.Context) OpaqueValueExpr(E->getExprLoc(), E->getType(),
+                                          E->getValueKind(), E->getObjectKind(),
+                                          SourceExpr.get());
+  return New;
 }
 
 template<typename Derived>