Fix lambda to block conversion in C++17 by avoiding copy elision for the

lambda capture used by the created block

The commit r288866 introduced guaranteed copy elision to C++ 17. This
unfortunately broke the lambda to block conversion in C++17 (the compiler
crashes when performing IRGen). This commit fixes the conversion by avoiding
copy elision for the capture that captures the lambda that's used in the block
created by the lambda to block conversion process.

rdar://31385153

Differential Revision: https://reviews.llvm.org/D31669

llvm-svn: 299646

1 files changed, 10 insertions, 1 deletions

diff --git a/clang/include/clang/Sema/Initialization.h b/clang/include/clang/Sema/Initialization.h
index c16b3d34eab..bd07b9ea9ae 100644
--- a/clang/include/clang/Sema/Initialization.h
+++ b/clang/include/clang/Sema/Initialization.h
@@ -70,6 +70,9 @@ public:
     /// \brief The entity being initialized is a field of block descriptor for
     /// the copied-in c++ object.
     EK_BlockElement,
+    /// The entity being initialized is a field of block descriptor for the
+    /// copied-in lambda object that's used in the lambda to block conversion.
+    EK_LambdaToBlockConversionBlockElement,
     /// \brief The entity being initialized is the real or imaginary part of a
     /// complex number.
     EK_ComplexElement,
@@ -260,7 +263,13 @@ public:
                                            QualType Type, bool NRVO) {
     return InitializedEntity(EK_BlockElement, BlockVarLoc, Type, NRVO);
   }
-  
+
+  static InitializedEntity InitializeLambdaToBlock(SourceLocation BlockVarLoc,
+                                                   QualType Type, bool NRVO) {
+    return InitializedEntity(EK_LambdaToBlockConversionBlockElement,
+                             BlockVarLoc, Type, NRVO);
+  }
+
   /// \brief Create the initialization entity for an exception object.
   static InitializedEntity InitializeException(SourceLocation ThrowLoc,
                                                QualType Type, bool NRVO) {