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.

This reapplies r341754, which was reverted in r341757 because it broke a
couple of bots. r341754 was calling markEscapingByrefs after the call to
PopFunctionScopeInfo, which caused the popped function scope to be
cleared out when the following code was compiled, for example:

$ cat test.m
struct A {
  id data[10];
};

void foo() {
  __block A v;
  ^{ (void)v; };
}

This commit calls markEscapingByrefs before calling PopFunctionScopeInfo
to prevent that from happening.

rdar://problem/39352313

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

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@343518 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 2 deletions

diff --git a/test/CodeGenObjCXX/arc-blocks.mm b/test/CodeGenObjCXX/arc-blocks.mm
index ef0561bad5..4791aff0b3 100644
--- a/test/CodeGenObjCXX/arc-blocks.mm
+++ b/test/CodeGenObjCXX/arc-blocks.mm
@@ -3,9 +3,9 @@
 // RUN: %clang_cc1 -std=gnu++98 -triple x86_64-apple-darwin10 -emit-llvm -fobjc-runtime-has-weak -fblocks -fobjc-arc -o - %s | FileCheck -check-prefix CHECK-NOEXCP %s
 
 // CHECK: [[A:.*]] = type { i64, [10 x i8*] }
+// CHECK: %[[STRUCT_BLOCK_DESCRIPTOR:.*]] = type { i64, i64 }
 // CHECK: %[[STRUCT_TEST1_S0:.*]] = type { i32 }
 // CHECK: %[[STRUCT_TRIVIAL_INTERNAL:.*]] = type { i32 }
-// CHECK: %[[STRUCT_BLOCK_DESCRIPTOR:.*]] = type { i64, i64 }
 
 // CHECK: [[LAYOUT0:@.*]] = private unnamed_addr constant [3 x i8] c" 9\00"
 
@@ -20,6 +20,7 @@ namespace test0 {
 
   void foo() {
     __block A v;
+    ^{ (void)v; };
   }
   // CHECK-LABEL:    define void @_ZN5test03fooEv() 
   // CHECK:      [[V:%.*]] = alloca [[BYREF_A:%.*]], align 8
@@ -32,7 +33,8 @@ namespace test0 {
   // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[BYREF_A]], [[BYREF_A]]* [[V]], i32 0, i32 7
   // CHECK-NEXT: call void @_ZN5test01AC1Ev([[A]]* [[T0]])
   // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[BYREF_A]], [[BYREF_A]]* [[V]], i32 0, i32 7
-  // CHECK-NEXT: [[T1:%.*]] = bitcast [[BYREF_A]]* [[V]] to i8*
+  // CHECK: bitcast [[BYREF_A]]* [[V]] to i8*
+  // CHECK: [[T1:%.*]] = bitcast [[BYREF_A]]* [[V]] to i8*
   // CHECK-NEXT: call void @_Block_object_dispose(i8* [[T1]], i32 8)
   // CHECK-NEXT: call void @_ZN5test01AD1Ev([[A]]* [[T0]])
   // CHECK-NEXT: ret void
@@ -53,6 +55,11 @@ namespace test0 {
   // CHECK-NEXT: ret void
 }
 
+// CHECK-LABEL: define linkonce_odr hidden void @__copy_helper_block_
+// CHECK-LABEL: define linkonce_odr hidden void @__destroy_helper_block_
+// CHECK-LABEL-O1: define linkonce_odr hidden void @__copy_helper_block_
+// CHECK-LABEL-O1: define linkonce_odr hidden void @__destroy_helper_block_
+
 namespace test1 {
 
 // Check that copy/dispose helper functions are exception safe.