[Sema] Mark implicitly-inserted ICE's as being part of explicit cast (PR38166)
Summary:
As discussed in [[ https://bugs.llvm.org/show_bug.cgi?id=38166 | PR38166 ]], we need to be able to distinqush whether the cast
we are visiting is actually a cast, or part of an `ExplicitCast`.
There are at least four ways to get there:
1. Introduce a new `CastKind`, and use it instead of `IntegralCast` if we are in `ExplicitCast`.
Would work, but does not scale - what if we will need more of these cast kinds?
2. Introduce a flag in `CastExprBits`, whether this cast is part of `ExplicitCast` or not.
Would work, but it isn't immediately clear where it needs to be set.
2. Fix `ScalarExprEmitter::VisitCastExpr()` to visit these `NoOp` casts.
As pointed out by @rsmith, CodeGenFunction::EmitMaterializeTemporaryExpr calls
skipRValueSubobjectAdjustments, which steps over the CK_NoOp cast`,
which explains why we currently don't visit those.
This is probably impossible, as @efriedma points out, that is intentional as per `[class.temporary]` in the standard
3. And the simplest one, just record which NoOp casts we skip.
It just kinda works as-is afterwards.
But, the approach with a flag is the least intrusive one, and is probably the best one overall.
Reviewers: rsmith, rjmccall, majnemer, efriedma
Reviewed By: rsmith
Subscribers: cfe-commits, aaron.ballman, vsk, llvm-commits, rsmith
Differential Revision: https://reviews.llvm.org/D49508
llvm-svn: 337815
diff --git a/clang/lib/Sema/SemaCast.cpp b/clang/lib/Sema/SemaCast.cpp
index b3f6be4..a669956 100644
--- a/clang/lib/Sema/SemaCast.cpp
+++ b/clang/lib/Sema/SemaCast.cpp
@@ -89,6 +89,14 @@
void CheckCXXCStyleCast(bool FunctionalCast, bool ListInitialization);
void CheckCStyleCast();
+ void updatePartOfExplicitCastFlags(CastExpr *CE) {
+ // Walk down from the CE to the OrigSrcExpr, and mark all immediate
+ // ImplicitCastExpr's as being part of ExplicitCastExpr. The original CE
+ // (which is a ExplicitCastExpr), and the OrigSrcExpr are not touched.
+ while ((CE = dyn_cast<ImplicitCastExpr>(CE->getSubExpr())))
+ CE->setIsPartOfExplicitCast(true);
+ }
+
/// Complete an apparently-successful cast operation that yields
/// the given expression.
ExprResult complete(CastExpr *castExpr) {
@@ -100,6 +108,7 @@
CK_Dependent, castExpr, nullptr,
castExpr->getValueKind());
}
+ updatePartOfExplicitCastFlags(castExpr);
return castExpr;
}