From b5a45bb77e05647f04bbd9780d70aabe9f251155 Mon Sep 17 00:00:00 2001
From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Fri, 31 May 2019 01:17:04 +0000
Subject: 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
---
 clang/lib/Sema/SemaLambda.cpp | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

(limited to 'clang/lib/Sema/SemaLambda.cpp')

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());
     }
 
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