From be9791a27874ad759d1cf53e5a4a49cde1f390eb Mon Sep 17 00:00:00 2001
From: Adrian Prantl <aprantl@apple.com>
Date: Mon, 18 Apr 2016 23:48:16 +0000
Subject: [PATCH] [ObjC++] Fix crash when emitting debug info for a block
 member capturing this.

rdar://problem/23871824

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@266698 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/CGDebugInfo.cpp                   | 11 ++++++++---
 .../debug-info-block-capture-this.mm          | 19 +++++++++++++++++++
 2 files changed, 27 insertions(+), 3 deletions(-)
 create mode 100644 test/CodeGenObjCXX/debug-info-block-capture-this.mm

diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index ae95dd8ed6..0c61496162 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -3262,9 +3262,14 @@ void CGDebugInfo::EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
 
     // If we have a null capture, this must be the C++ 'this' capture.
     if (!capture) {
-      const CXXMethodDecl *method =
-          cast<CXXMethodDecl>(blockDecl->getNonClosureContext());
-      QualType type = method->getThisType(C);
+      QualType type;
+      if (auto *Method =
+              cast_or_null<CXXMethodDecl>(blockDecl->getNonClosureContext()))
+        type = Method->getThisType(C);
+      else if (auto *RDecl = dyn_cast<CXXRecordDecl>(blockDecl->getParent()))
+        type = QualType(RDecl->getTypeForDecl(), 0);
+      else
+        llvm_unreachable("unexpected block declcontext");
 
       fields.push_back(createFieldType("this", type, 0, loc, AS_public,
                                        offsetInBits, tunit, tunit));
diff --git a/test/CodeGenObjCXX/debug-info-block-capture-this.mm b/test/CodeGenObjCXX/debug-info-block-capture-this.mm
new file mode 100644
index 0000000000..a1b120608c
--- /dev/null
+++ b/test/CodeGenObjCXX/debug-info-block-capture-this.mm
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin -std=c++14 -fblocks -debug-info-kind=standalone -emit-llvm %s -o - | FileCheck %s
+struct test
+{
+    int func() { return 1; }
+    int (^block)() = ^{ return func(); };
+};
+
+int main(int argc, const char * argv[]) {
+    test t;
+    return t.block();
+}
+
+// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "__block_literal_1",
+// CHECK-SAME:             elements: ![[ELEMS:.*]])
+// CHECK: ![[ELEMS]] = !{{{.*}}, ![[THIS:[0-9]+]]}
+// CHECK: ![[THIS]] = !DIDerivedType(tag: DW_TAG_member, name: "this",
+// CHECK-SAME:                       baseType: !"_ZTS4test",
+
+
-- 
2.50.1