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

1 files changed, 2 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/block-capture.cpp b/clang/test/CodeGenCXX/block-capture.cpp
index 623838357a3..515d64d35da 100644
--- a/clang/test/CodeGenCXX/block-capture.cpp
+++ b/clang/test/CodeGenCXX/block-capture.cpp
@@ -4,10 +4,12 @@
 // CHECK: [[baz:%[0-9a-z_]*]] = alloca %struct.__block_byref_baz
 // CHECK: [[bazref:%[0-9a-z_\.]*]] = getelementptr inbounds %struct.__block_byref_baz, %struct.__block_byref_baz* [[baz]], i32 0, i32 1
 // CHECK: store %struct.__block_byref_baz* [[baz]], %struct.__block_byref_baz** [[bazref]]
+// CHECK: bitcast %struct.__block_byref_baz* [[baz]] to i8*
 // CHECK: [[disposable:%[0-9a-z_]*]] = bitcast %struct.__block_byref_baz* [[baz]] to i8*
 // CHECK: call void @_Block_object_dispose(i8* [[disposable]]
 
 int main() {
   __block int baz = [&]() { return 0; }();
+  ^{ (void)baz; };
   return 0;
 }