Defer building 'this' captures until we have left the capturing region

and returned to the context in which 'this' should be captured.

This means we now always mark 'this' referenced from the context in
which it's actually referenced, rather than potentially from some
context nested within that.

llvm-svn: 362182

1 files changed, 20 insertions, 3 deletions

diff --git a/clang/lib/Sema/SemaLambda.cpp b/clang/lib/Sema/SemaLambda.cpp
index a17a3da67fd..d3f3b60926f 100644
--- a/clang/lib/Sema/SemaLambda.cpp
+++ b/clang/lib/Sema/SemaLambda.cpp
@@ -1431,6 +1431,24 @@ static void addBlockPointerConversion(Sema &S,
   Class->addDecl(Conversion);
 }
 
+ExprResult Sema::performThisCaptureInitialization(const Capture &Cap,
+                                                  bool IsImplicit) {
+  QualType ThisTy = getCurrentThisType();
+  SourceLocation Loc = Cap.getLocation();
+  Expr *This = BuildCXXThisExpr(Loc, ThisTy, IsImplicit);
+  if (Cap.isReferenceCapture())
+    return This;
+
+  // Capture (by copy) of '*this'.
+  Expr *StarThis = CreateBuiltinUnaryOp(Loc, UO_Deref, This).get();
+  InitializedEntity Entity = InitializedEntity::InitializeLambdaCapture(
+      nullptr, Cap.getCaptureType(), Loc);
+  InitializationKind InitKind =
+      InitializationKind::CreateDirect(Loc, Loc, Loc);
+  InitializationSequence Init(*this, Entity, InitKind, StarThis);
+  return Init.Perform(*this, Entity, InitKind, StarThis);
+}
+
 static ExprResult performLambdaVarCaptureInitialization(
     Sema &S, const Capture &Capture, FieldDecl *Field,
     SourceLocation ImplicitCaptureLoc, bool IsImplicitCapture) {
@@ -1680,10 +1698,11 @@ ExprResult Sema::BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
                      getLocForEndOfToken(CaptureDefaultLoc), ", this");
         }
 
+        ExprResult Init = performThisCaptureInitialization(From, IsImplicit);
         Captures.push_back(
             LambdaCapture(From.getLocation(), IsImplicit,
                           From.isCopyCapture() ? LCK_StarThis : LCK_This));
-        CaptureInits.push_back(From.getThisInitExpr());
+        CaptureInits.push_back(Init.get());
         continue;
       }
       if (From.isVLATypeCapture()) {
@@ -1703,8 +1722,6 @@ ExprResult Sema::BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
               ? Var->getInit()
               : performLambdaVarCaptureInitialization(
                     *this, From, Field, CaptureDefaultLoc, IsImplicit);
-      if (Init.isInvalid())
-        return ExprError();
       CaptureInits.push_back(Init.get());
     }