From d55661db3cba15aab1a7dcf12e13a2e000a8e051 Mon Sep 17 00:00:00 2001 From: Roman Lebedev Date: Tue, 24 Jul 2018 08:16:50 +0000 Subject: [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 --- clang/lib/Sema/SemaCast.cpp | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'clang/lib/Sema/SemaCast.cpp') diff --git a/clang/lib/Sema/SemaCast.cpp b/clang/lib/Sema/SemaCast.cpp index b3f6be4aec7..a669956422c 100644 --- a/clang/lib/Sema/SemaCast.cpp +++ b/clang/lib/Sema/SemaCast.cpp @@ -89,6 +89,14 @@ namespace { 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(CE->getSubExpr()))) + CE->setIsPartOfExplicitCast(true); + } + /// Complete an apparently-successful cast operation that yields /// the given expression. ExprResult complete(CastExpr *castExpr) { @@ -100,6 +108,7 @@ namespace { CK_Dependent, castExpr, nullptr, castExpr->getValueKind()); } + updatePartOfExplicitCastFlags(castExpr); return castExpr; } -- cgit v1.2.3