clang/test/C/C2x/n2350.c

   1 // RUN: %clang_cc1 -fsyntax-only -verify=silent %s
   2 // RUN: %clang_cc1 -fsyntax-only -verify=cpp -x c++ %s
   3 // RUN: %clang_cc1 -fsyntax-only -pedantic -Wno-comment -verify %s
   4 // RUN: %clang_cc1 -fsyntax-only -pedantic -Wno-comment -std=c89 -verify %s
   5 // RUN: %clang_cc1 -fsyntax-only -pedantic -Wno-comment -std=c99 -verify %s
   6 // RUN: %clang_cc1 -fsyntax-only -pedantic -Wno-comment -std=c11 -verify %s
   7 // RUN: %clang_cc1 -fsyntax-only -pedantic -Wno-comment -std=c17 -verify %s
   8 // RUN: %clang_cc1 -fsyntax-only -pedantic -Wno-comment -std=c2x -verify %s
   9
  10 // silent-no-diagnostics
  11
  12 // Reject definitions in __builtin_offsetof
  13 // https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm
  14 int simple(void) {
  15   return __builtin_offsetof(struct A // cpp-error {{'A' cannot be defined in a type specifier}} \
  16                                         expected-warning {{defining a type within '__builtin_offsetof' is a Clang extension}}
  17   {
  18     int a;
  19     struct B // expected-warning {{defining a type within '__builtin_offsetof' is a Clang extension}}
  20     {
  21       int c;
  22       int d;
  23     } x;
  24   }, a);
  25 }
  26
  27 int anonymous_struct(void) {
  28   return __builtin_offsetof(struct // cpp-error-re {{'(unnamed struct at {{.*}})' cannot be defined in a type specifier}} \
  29                                       expected-warning {{defining a type within '__builtin_offsetof' is a Clang extension}}
  30   {
  31     int a;
  32     int b;
  33   }, a);
  34 }
  35
  36 int struct_in_second_param(void) {
  37   struct A {
  38     int a, b;
  39     int x[20];
  40   };
  41   return __builtin_offsetof(struct A, x[sizeof(struct B{int a;})]); // cpp-error {{'B' cannot be defined in a type specifier}}
  42 }
  43
  44
  45 #define offsetof(TYPE, MEMBER) __builtin_offsetof(TYPE, MEMBER)
  46
  47
  48 int macro(void) {
  49   return offsetof(struct A // cpp-error {{'A' cannot be defined in a type specifier}} \
  50                               expected-warning 2 {{defining a type within 'offsetof' is a Clang extension}}
  51   {
  52     int a;
  53     struct B // verifier seems to think the error is emitted by the macro
  54              // In fact the location of the error is "B" on the line above
  55     {
  56       int c;
  57       int d;
  58     } x;
  59   }, a);
  60 }
  61
  62 #undef offsetof
  63
  64 #define offsetof(TYPE, MEMBER) (&((TYPE *)0)->MEMBER)
  65
  66 // no warning for traditional offsetof as a function-like macro
  67 int * macro_func(void) {
  68   return offsetof(struct A // cpp-error {{'A' cannot be defined in a type specifier}}
  69   {
  70     int a;
  71     int b;
  72   }, a);
  73 }