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// RUN: %clang_cc1 -triple arm64-apple-ios7.0 -target-abi darwinpcs -emit-llvm -o - %s | FileCheck %s
// RUN: %clang_cc1 -triple aarch64-linux-gnu -emit-llvm -o - -x c %s | FileCheck %s --check-prefix=CHECK-GNU-C
// RUN: %clang_cc1 -triple aarch64-linux-gnu -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-GNU-CXX
// Empty structs are ignored for PCS purposes on Darwin and in C mode elsewhere.
// In C++ mode on ELF they consume a register slot though. Functions are
// slightly bigger than minimal to make confirmation against actual GCC
// behaviour easier.
#if __cplusplus
#define EXTERNC extern "C"
#else
#define EXTERNC
#endif
struct Empty {};
// CHECK: define{{.*}} i32 @empty_arg(i32 noundef %a)
// CHECK-GNU-C: define{{.*}} i32 @empty_arg(i32 noundef %a)
// CHECK-GNU-CXX: define{{.*}} i32 @empty_arg(i8 %e.coerce, i32 noundef %a)
EXTERNC int empty_arg(struct Empty e, int a) {
return a;
}
// CHECK: define{{.*}} void @empty_ret()
// CHECK-GNU-C: define{{.*}} void @empty_ret()
// CHECK-GNU-CXX: define{{.*}} void @empty_ret()
EXTERNC struct Empty empty_ret(void) {
struct Empty e;
return e;
}
// However, what counts as "empty" is a baroque mess. This is super-empty, it's
// ignored even in C++ mode. It also has sizeof == 0, violating C++, but that's
// legacy for you:
struct SuperEmpty {
int arr[0];
};
// CHECK: define{{.*}} i32 @super_empty_arg(i32 noundef %a)
// CHECK-GNU-C: define{{.*}} i32 @super_empty_arg(i32 noundef %a)
// CHECK-GNU-CXX: define{{.*}} i32 @super_empty_arg(i32 noundef %a)
EXTERNC int super_empty_arg(struct SuperEmpty e, int a) {
return a;
}
// This is not empty. It has 0 size but consumes a register slot for GCC.
struct SortOfEmpty {
struct SuperEmpty e;
};
// CHECK: define{{.*}} i32 @sort_of_empty_arg(i32 noundef %a)
// CHECK-GNU-C: define{{.*}} i32 @sort_of_empty_arg(i32 noundef %a)
// CHECK-GNU-CXX: define{{.*}} i32 @sort_of_empty_arg(i8 %e.coerce, i32 noundef %a)
EXTERNC int sort_of_empty_arg(struct Empty e, int a) {
return a;
}
// CHECK: define{{.*}} void @sort_of_empty_ret()
// CHECK-GNU-C: define{{.*}} void @sort_of_empty_ret()
// CHECK-GNU-CXX: define{{.*}} void @sort_of_empty_ret()
EXTERNC struct SortOfEmpty sort_of_empty_ret(void) {
struct SortOfEmpty e;
return e;
}
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