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

2 files changed, 32 insertions, 1 deletions

diff --git a/clang/test/SemaObjCXX/blocks.mm b/clang/test/SemaObjCXX/blocks.mm
index bdd5538e92b..5f735241720 100644
--- a/clang/test/SemaObjCXX/blocks.mm
+++ b/clang/test/SemaObjCXX/blocks.mm
@@ -76,21 +76,27 @@ namespace N1 {
 }
 
 // Make sure we successfully instantiate the copy constructor of a
-// __block variable's type.
+// __block variable's type when the variable is captured by an escaping block.
 namespace N2 {
   template <int n> struct A {
     A() {}
     A(const A &other) {
       int invalid[-n]; // expected-error 2 {{array with a negative size}}
     }
+    void m() {}
   };
 
+  typedef void (^BlockFnTy)();
+  void func(BlockFnTy);
+
   void test1() {
     __block A<1> x; // expected-note {{requested here}}
+    func(^{ x.m(); });
   }
 
   template <int n> void test2() {
     __block A<n> x; // expected-note {{requested here}}
+    func(^{ x.m(); });
   }
   template void test2<2>();
 }
diff --git a/clang/test/SemaObjCXX/noescape.mm b/clang/test/SemaObjCXX/noescape.mm
index 9432a3a48a0..efa2a76d668 100644
--- a/clang/test/SemaObjCXX/noescape.mm
+++ b/clang/test/SemaObjCXX/noescape.mm
@@ -8,6 +8,7 @@ struct S {
   void m();
 };
 
+void escapingFunc0(BlockTy);
 void noescapeFunc0(id, __attribute__((noescape)) BlockTy);
 void noescapeFunc1(id, [[clang::noescape]] BlockTy);
 void noescapeFunc2(__attribute__((noescape)) int *); // expected-note {{previous declaration is here}}
@@ -127,3 +128,27 @@ __attribute__((objc_root_class))
 -(void) m1:(int*) p {
 }
 @end
+
+struct S6 {
+  S6();
+  S6(const S6 &) = delete; // expected-note 3 {{'S6' has been explicitly marked deleted here}}
+  int f;
+};
+
+void test1() {
+  id a;
+  // __block variables that are not captured by escaping blocks don't
+  // necessitate having accessible copy constructors.
+  __block S6 b0;
+  __block S6 b1; // expected-error {{call to deleted constructor of 'S6'}}
+  __block S6 b2; // expected-error {{call to deleted constructor of 'S6'}}
+  __block S6 b3; // expected-error {{call to deleted constructor of 'S6'}}
+
+  noescapeFunc0(a, ^{ (void)b0; });
+  escapingFunc0(^{ (void)b1; });
+  {
+    noescapeFunc0(a, ^{ (void)b0; (void)b1; });
+  }
+  noescapeFunc0(a, ^{ escapingFunc0(^{ (void)b2; }); });
+  escapingFunc0(^{ noescapeFunc0(a, ^{ (void)b3; }); });
+}