1 // RUN: %clang_cc1 -std=gnu2x -triple x86_64-linux-gnu %s -emit-llvm -o - \ 2 // RUN: | FileCheck %s --check-prefixes=CHECK,CHECK-NOM 3 // RUN: %clang_cc1 -std=gnu2x -triple x86_64-linux-gnu %s -emit-llvm -o - \ 4 // RUN: -mfunction-return=keep | FileCheck %s \ 5 // RUN: --check-prefixes=CHECK,CHECK-KEEP 6 // RUN: %clang_cc1 -std=gnu2x -triple x86_64-linux-gnu %s -emit-llvm -o - \ 7 // RUN: -mfunction-return=thunk-extern | FileCheck %s \ 8 // RUN: --check-prefixes=CHECK,CHECK-EXTERN 9 10 #if !__has_attribute(function_return) 11 #error "missing attribute support for function_return" 12 #endif 13 14 // CHECK: @keep() [[KEEP:#[0-9]+]] 15 __attribute__((function_return("keep"))) void keep(void) {} 16 17 // CHECK: @keep2() [[KEEP:#[0-9]+]] 18 [[gnu::function_return("keep")]] void keep2(void) {} 19 20 // CHECK: @thunk_extern() [[EXTERN:#[0-9]+]] 21 __attribute__((function_return("thunk-extern"))) void thunk_extern(void) {} 22 23 // CHECK: @thunk_extern2() [[EXTERN:#[0-9]+]] 24 [[gnu::function_return("thunk-extern")]] void thunk_extern2(void) {} 25 26 // CHECK: @double_thunk_keep() [[KEEP]] 27 // clang-format off 28 __attribute__((function_return("thunk-extern"))) 29 __attribute__((function_return("keep"))) 30 void double_thunk_keep(void) {} 31 32 // CHECK: @double_thunk_keep2() [[KEEP]] 33 [[gnu::function_return("thunk-extern")]][[gnu::function_return("keep")]] 34 void double_thunk_keep2(void) {} 35 36 // CHECK: @double_keep_thunk() [[EXTERN]] 37 __attribute__((function_return("keep"))) 38 __attribute__((function_return("thunk-extern"))) 39 void double_keep_thunk(void) {} 40 41 // CHECK: @double_keep_thunk2() [[EXTERN]] 42 [[gnu::function_return("thunk-keep")]][[gnu::function_return("thunk-extern")]] 43 void double_keep_thunk2(void) {} 44 45 // CHECK: @thunk_keep() [[KEEP]] 46 __attribute__((function_return("thunk-extern"), function_return("keep"))) 47 void thunk_keep(void) {} 48 49 // CHECK: @thunk_keep2() [[KEEP]] 50 [[gnu::function_return("thunk-extern"), gnu::function_return("keep")]] 51 void thunk_keep2(void) {} 52 53 // CHECK: @keep_thunk() [[EXTERN]] 54 __attribute__((function_return("keep"), function_return("thunk-extern"))) 55 void keep_thunk(void) {} 56 57 // CHECK: @keep_thunk2() [[EXTERN]] 58 [[gnu::function_return("keep"), gnu::function_return("thunk-extern")]] 59 void keep_thunk2(void) {} 60 // clang-format on 61 62 void undef(void); 63 // CHECK: @undef() [[KEEP]] 64 __attribute__((function_return("keep"))) void undef(void) {} 65 66 void undef2(void); 67 // CHECK: @undef2() [[EXTERN]] 68 __attribute__((function_return("thunk-extern"))) void undef2(void) {} 69 70 __attribute__((function_return("thunk-extern"))) void change_def(void); 71 // CHECK: @change_def() [[KEEP]] 72 __attribute__((function_return("keep"))) void change_def(void) {} 73 74 __attribute__((function_return("keep"))) void change_def2(void); 75 // CHECK: @change_def2() [[EXTERN]] 76 __attribute__((function_return("thunk-extern"))) void change_def2(void) {} 77 78 __attribute__((function_return("thunk-extern"))) void change_def3(void); 79 // CHECK: @change_def3() [[KEEP]] 80 [[gnu::function_return("keep")]] void change_def3(void) {} 81 82 [[gnu::function_return("keep")]] void change_def4(void); 83 // CHECK: @change_def4() [[EXTERN]] 84 __attribute__((function_return("thunk-extern"))) void change_def4(void) {} 85 86 // When there is no -mfunction-return= flag set (NOM) or it's set to keep, 87 // we don't emit anything into the IR for unattributed functions. 88 89 // CHECK-NOM: @no_attrs() [[NOATTR:#[0-9]+]] 90 // CHECK-KEEP: @no_attrs() [[NOATTR:#[0-9]+]] 91 // CHECK-EXTERN: @no_attrs() [[EXTERN]] 92 void no_attrs(void) {} 93 94 // CHECK-NOM-NOT: [[NOATTR]] = {{.*}}fn_ret_thunk_extern 95 // CHECK-KEEP-NOT: [[NOATTR]] = {{.*}}fn_ret_thunk_extern 96 // CHECK: [[EXTERN]] = {{.*}}fn_ret_thunk_extern 97