[ObjC] Allow declaring __strong pointer fields in structs in Objective-C
ARC mode.
Declaring __strong pointer fields in structs was not allowed in
Objective-C ARC until now because that would make the struct non-trivial
to default-initialize, copy/move, and destroy, which is not something C
was designed to do. This patch lifts that restriction.
Special functions for non-trivial C structs are synthesized that are
needed to default-initialize, copy/move, and destroy the structs and
manage the ownership of the objects the __strong pointer fields point
to. Non-trivial structs passed to functions are destructed in the callee
function.
rdar://problem/33599681
Differential Revision: https://reviews.llvm.org/D41228
llvm-svn: 326307
diff --git a/clang/test/SemaObjC/strong-in-c-struct.m b/clang/test/SemaObjC/strong-in-c-struct.m
new file mode 100644
index 0000000..5dd5f94
--- /dev/null
+++ b/clang/test/SemaObjC/strong-in-c-struct.m
@@ -0,0 +1,56 @@
+// RUN: %clang_cc1 -triple arm64-apple-ios11 -fobjc-arc -fblocks -fobjc-runtime=ios-11.0 -fsyntax-only -verify %s
+
+typedef struct {
+ id a;
+} Strong;
+
+void callee_variadic(const char *, ...);
+
+void test_variadic(void) {
+ Strong t;
+ callee_variadic("s", t); // expected-error {{cannot pass non-trivial C object of type 'Strong' by value to variadic function}}
+}
+
+void test_jump0(int cond) {
+ switch (cond) {
+ case 0:
+ ;
+ Strong x; // expected-note {{jump bypasses initialization of variable of non-trivial C struct type}}
+ break;
+ case 1: // expected-error {{cannot jump from switch statement to this case label}}
+ x.a = 0;
+ break;
+ }
+}
+
+void test_jump1(void) {
+ static void *ips[] = { &&L0 };
+L0: // expected-note {{possible target of indirect goto}}
+ ;
+ Strong x; // expected-note {{jump exits scope of variable with non-trivial destructor}}
+ goto *ips; // expected-error {{cannot jump}}
+}
+
+typedef void (^BlockTy)(void);
+void func(BlockTy);
+void func2(Strong);
+
+void test_block_scope0(int cond) {
+ Strong x; // expected-note {{jump enters lifetime of block which captures a C struct that is non-trivial to destroy}}
+ switch (cond) {
+ case 0:
+ func(^{ func2(x); });
+ break;
+ default: // expected-error {{cannot jump from switch statement to this case label}}
+ break;
+ }
+}
+
+void test_block_scope1(void) {
+ static void *ips[] = { &&L0 };
+L0: // expected-note {{possible target of indirect goto}}
+ ;
+ Strong x; // expected-note {{jump exits scope of variable with non-trivial destructor}} expected-note {{jump exits lifetime of block which captures a C struct that is non-trivial to destroy}}
+ func(^{ func2(x); });
+ goto *ips; // expected-error {{cannot jump}}
+}