From 2e00b98027b51ee5bfb88a4daea8b78bf9a01e62 Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahatanaka@apple.com>
Date: Sat, 8 Sep 2018 20:03:00 +0000
Subject: Distinguish `__block` variables that are captured by escaping blocks
 from those that aren't.

This patch changes the way __block variables that aren't captured by
escaping blocks are handled:

- Since non-escaping blocks on the stack never get copied to the heap
  (see https://reviews.llvm.org/D49303), Sema shouldn't error out when
  the type of a non-escaping __block variable doesn't have an accessible
  copy constructor.

- IRGen doesn't have to use the specialized byref structure (see
  https://clang.llvm.org/docs/Block-ABI-Apple.html#id8) for a
  non-escaping __block variable anymore. Instead IRGen can emit the
  variable as a normal variable and copy the reference to the block
  literal. Byref copy/dispose helpers aren't needed either.

rdar://problem/39352313

Differential Revision: https://reviews.llvm.org/D51564

llvm-svn: 341754
---
 clang/test/CodeGenCXX/noescape.cpp | 31 ++++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

(limited to 'clang/test/CodeGenCXX/noescape.cpp')

diff --git a/clang/test/CodeGenCXX/noescape.cpp b/clang/test/CodeGenCXX/noescape.cpp
index 90d24de3da2..40bc839788a 100644
--- a/clang/test/CodeGenCXX/noescape.cpp
+++ b/clang/test/CodeGenCXX/noescape.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -triple x86_64-apple-darwin -std=c++11 -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-apple-darwin -std=c++11 -emit-llvm -fblocks -o - %s | FileCheck %s
 
 struct S {
   int a[4];
@@ -65,3 +65,32 @@ typedef void (*NoEscapeFunc)(__attribute__((noescape)) int *);
 void test3(NoEscapeFunc f, int *p) {
   f(p);
 }
+
+namespace TestByref {
+
+struct S {
+  S();
+  ~S();
+  S(const S &);
+  int a;
+};
+
+typedef void (^BlockTy)(void);
+S &getS();
+void noescapefunc(__attribute__((noescape)) BlockTy);
+
+// Check that __block variables with reference types are handled correctly.
+
+// CHECK: define void @_ZN9TestByref4testEv(
+// CHECK: %[[X:.*]] = alloca %[[STRUCT_TESTBYREF:.*]]*, align 8
+// CHECK: %[[BLOCK:.*]] = alloca <{ i8*, i32, i32, i8*, %{{.*}}*, %[[STRUCT_TESTBYREF]]* }>, align 8
+// CHECK: %[[BLOCK_CAPTURED:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %{{.*}}*, %[[STRUCT_TESTBYREF]]* }>, <{ i8*, i32, i32, i8*, %{{.*}}*, %[[STRUCT_TESTBYREF]]* }>* %[[BLOCK]], i32 0, i32 5
+// CHECK: %[[V0:.*]] = load %[[STRUCT_TESTBYREF]]*, %[[STRUCT_TESTBYREF]]** %[[X]], align 8
+// CHECK: store %[[STRUCT_TESTBYREF]]* %[[V0]], %[[STRUCT_TESTBYREF]]** %[[BLOCK_CAPTURED]], align 8
+
+void test() {
+  __block S &x = getS();
+  noescapefunc(^{ (void)x; });
+}
+
+}
-- 
cgit v1.2.3