[ObjC][CodeGen] Remove an assert that is no longer correct.

clang asserts when compiling the following code because r231508 made
changes to promote constant temporary arrays and records to globals
with constant initializers:

std::vector<NSString*> strs = {@"a", @"b"};

This commit changes the code to return early if the object returned by
createReferenceTemporary is a global variable with an initializer.

rdar://problem/25504992
rdar://problem/25955179

Differential Revision: http://reviews.llvm.org/D20045

llvm-svn: 269385

2 files changed, 27 insertions, 4 deletions

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 8896eb4db12..1001a00b62e 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -361,9 +361,16 @@ EmitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *M) {
                            ConvertTypeForMem(E->getType())
                              ->getPointerTo(Object.getAddressSpace())),
                        Object.getAlignment());
-      // We should not have emitted the initializer for this temporary as a
-      // constant.
-      assert(!Var->hasInitializer());
+
+      // createReferenceTemporary will promote the temporary to a global with a
+      // constant initializer if it can.  It can only do this to a value of
+      // ARC-manageable type if the value is global and therefore "immune" to
+      // ref-counting operations.  Therefore we have no need to emit either a
+      // dynamic initialization or a cleanup and we can just return the address
+      // of the temporary.
+      if (Var->hasInitializer())
+        return MakeAddrLValue(Object, M->getType(), AlignmentSource::Decl);
+
       Var->setInitializer(CGM.EmitNullConstant(E->getType()));
     }
     LValue RefTempDst = MakeAddrLValue(Object, M->getType(),
diff --git a/clang/test/CodeGenObjCXX/arc-cxx11-init-list.mm b/clang/test/CodeGenObjCXX/arc-cxx11-init-list.mm
index 7e1f10c35fb..27442f81304 100644
--- a/clang/test/CodeGenObjCXX/arc-cxx11-init-list.mm
+++ b/clang/test/CodeGenObjCXX/arc-cxx11-init-list.mm
@@ -1,5 +1,11 @@
 // RUN: %clang_cc1 -triple armv7-ios5.0 -std=c++11 -fobjc-arc -Os -emit-llvm -o - %s | FileCheck %s
 
+// CHECK: @[[STR0:.*]] = private unnamed_addr constant [5 x i8] c"str0\00", section "__TEXT,__cstring,cstring_literals"
+// CHECK: @[[UNNAMED_CFSTRING0:.*]] = private constant %struct.__NSConstantString_tag { i32* getelementptr inbounds ([0 x i32], [0 x i32]* @__CFConstantStringClassReference, i32 0, i32 0), i32 1992, i8* getelementptr inbounds ([5 x i8], [5 x i8]* @[[STR0]], i32 0, i32 0), i32 4 }, section "__DATA,__cfstring"
+// CHECK: @[[STR1:.*]] = private unnamed_addr constant [5 x i8] c"str1\00", section "__TEXT,__cstring,cstring_literals"
+// CHECK: @[[UNNAMED_CFSTRING1:.*]] = private constant %struct.__NSConstantString_tag { i32* getelementptr inbounds ([0 x i32], [0 x i32]* @__CFConstantStringClassReference, i32 0, i32 0), i32 1992, i8* getelementptr inbounds ([5 x i8], [5 x i8]* @[[STR1]], i32 0, i32 0), i32 4 }, section "__DATA,__cfstring"
+// CHECK: @[[REFTMP:.*]] = private constant [2 x i8*] [i8* bitcast (%struct.__NSConstantString_tag* @[[UNNAMED_CFSTRING0]] to i8*), i8* bitcast (%struct.__NSConstantString_tag* @[[UNNAMED_CFSTRING1]] to i8*)]
+
 typedef __SIZE_TYPE__ size_t;
 
 namespace std {
@@ -32,6 +38,17 @@ extern "C" void multiple() { function({ [I new], [I new] }); }
 // CHECK-NEXT: store i8* [[INSTANCE]], i8** [[CAST]],
 // CHECK: call void @objc_release(i8* {{.*}})
 
+std::initializer_list<id> foo1() {
+  return {@"str0", @"str1"};
+}
+
+// CHECK: define void @_Z4foo1v(%"class.std::initializer_list.0"* {{.*}} %[[AGG_RESULT:.*]])
+// CHECK: %[[BEGIN:.*]] = getelementptr inbounds %"class.std::initializer_list.0", %"class.std::initializer_list.0"* %[[AGG_RESULT]], i32 0, i32 0
+// CHECK: store i8** getelementptr inbounds ([2 x i8*], [2 x i8*]* @[[REFTMP]], i32 0, i32 0), i8*** %[[BEGIN]]
+// CHECK: %[[SIZE:.*]] = getelementptr inbounds %"class.std::initializer_list.0", %"class.std::initializer_list.0"* %[[AGG_RESULT]], i32 0, i32 1
+// CHECK: store i32 2, i32* %[[SIZE]]
+// CHECK: ret void
+
 void external();
 
 extern "C" void extended() {
@@ -49,4 +66,3 @@ std::initializer_list<I *> il = { [I new] };
 // CHECK: [[INSTANCE:%.*]] = {{.*}} call i8* bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to i8* (i8*, i8*)*)(i8* {{.*}}, i8* {{.*}})
 // CHECK-NEXT: store i8* [[INSTANCE]], i8** bitcast ([1 x %0*]* @_ZGR2il_ to i8**)
 // CHECK: {{.*}} call void @objc_autoreleasePoolPop(i8* [[POOL]])
-