| 1 | // RUN: %clang_cc1 -triple arm64-apple-ios7.0 -target-abi darwinpcs -emit-llvm -o - %s | FileCheck %s |
|---|
| 2 | // RUN: %clang_cc1 -triple aarch64-linux-gnu -emit-llvm -o - -x c %s | FileCheck %s --check-prefix=CHECK-GNU-C |
|---|
| 3 | // RUN: %clang_cc1 -triple aarch64-linux-gnu -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-GNU-CXX |
|---|
| 4 | |
|---|
| 5 | // Empty structs are ignored for PCS purposes on Darwin and in C mode elsewhere. |
|---|
| 6 | // In C++ mode on ELF they consume a register slot though. Functions are |
|---|
| 7 | // slightly bigger than minimal to make confirmation against actual GCC |
|---|
| 8 | // behaviour easier. |
|---|
| 9 | |
|---|
| 10 | #if __cplusplus |
|---|
| 11 | #define EXTERNC extern "C" |
|---|
| 12 | #else |
|---|
| 13 | #define EXTERNC |
|---|
| 14 | #endif |
|---|
| 15 | |
|---|
| 16 | struct Empty {}; |
|---|
| 17 | |
|---|
| 18 | // CHECK: define i32 @empty_arg(i32 %a) |
|---|
| 19 | // CHECK-GNU-C: define i32 @empty_arg(i32 %a) |
|---|
| 20 | // CHECK-GNU-CXX: define i32 @empty_arg(i8 %e.coerce, i32 %a) |
|---|
| 21 | EXTERNC int empty_arg(struct Empty e, int a) { |
|---|
| 22 | return a; |
|---|
| 23 | } |
|---|
| 24 | |
|---|
| 25 | // CHECK: define void @empty_ret() |
|---|
| 26 | // CHECK-GNU-C: define void @empty_ret() |
|---|
| 27 | // CHECK-GNU-CXX: define void @empty_ret() |
|---|
| 28 | EXTERNC struct Empty empty_ret() { |
|---|
| 29 | struct Empty e; |
|---|
| 30 | return e; |
|---|
| 31 | } |
|---|
| 32 | |
|---|
| 33 | // However, what counts as "empty" is a baroque mess. This is super-empty, it's |
|---|
| 34 | // ignored even in C++ mode. It also has sizeof == 0, violating C++, but that's |
|---|
| 35 | // legacy for you: |
|---|
| 36 | |
|---|
| 37 | struct SuperEmpty { |
|---|
| 38 | int arr[0]; |
|---|
| 39 | }; |
|---|
| 40 | |
|---|
| 41 | // CHECK: define i32 @super_empty_arg(i32 %a) |
|---|
| 42 | // CHECK-GNU-C: define i32 @super_empty_arg(i32 %a) |
|---|
| 43 | // CHECK-GNU-CXX: define i32 @super_empty_arg(i32 %a) |
|---|
| 44 | EXTERNC int super_empty_arg(struct SuperEmpty e, int a) { |
|---|
| 45 | return a; |
|---|
| 46 | } |
|---|
| 47 | |
|---|
| 48 | // This is not empty. It has 0 size but consumes a register slot for GCC. |
|---|
| 49 | |
|---|
| 50 | struct SortOfEmpty { |
|---|
| 51 | struct SuperEmpty e; |
|---|
| 52 | }; |
|---|
| 53 | |
|---|
| 54 | // CHECK: define i32 @sort_of_empty_arg(i32 %a) |
|---|
| 55 | // CHECK-GNU-C: define i32 @sort_of_empty_arg(i32 %a) |
|---|
| 56 | // CHECK-GNU-CXX: define i32 @sort_of_empty_arg(i8 %e.coerce, i32 %a) |
|---|
| 57 | EXTERNC int sort_of_empty_arg(struct Empty e, int a) { |
|---|
| 58 | return a; |
|---|
| 59 | } |
|---|
| 60 | |
|---|
| 61 | // CHECK: define void @sort_of_empty_ret() |
|---|
| 62 | // CHECK-GNU-C: define void @sort_of_empty_ret() |
|---|
| 63 | // CHECK-GNU-CXX: define void @sort_of_empty_ret() |
|---|
| 64 | EXTERNC struct SortOfEmpty sort_of_empty_ret() { |
|---|
| 65 | struct SortOfEmpty e; |
|---|
| 66 | return e; |
|---|
| 67 | } |
|---|
| 68 | |
|---|