gcc/testsuite/gcc.dg/pack-test-1.c

   1 /* Test semantics of #pragma pack.
   2    Contributed by Mike Coleman <mcoleman2@kc.rr.com> */
   3
   4 /* { dg-do compile { target *-*-linux* *-*-cygwin* powerpc*-*-eabi* } } */
   5
   6 /* We only test the alignment of char, short, and int, because these
   7    are the only ones that are pretty certain to be the same across
   8    platforms (and maybe not even those).  Mainly we're just testing
   9    whether pushing and popping seem to be working correctly, and
  10    verifying the (alignment == 1) case, which is really the only
  11    reason anyone would use this pragma anyway.
  12 */
  13
  14 #include <stddef.h>
  15
  16 /* gap in bytes between fields a and b in struct s */
  17 #define gap(s, a, b) (offsetof(struct s, a) - offsetof(struct s, b))
  18 /* generalized compile-time test expression */
  19 #define test(n, expr) int test_##n [(expr) ? 1 : -1]
  20 /* test a gap */
  21 #define testgap(n, a, b, val) test(n, gap(SNAME, a, b) == val)
  22
  23 #define SNAME s0
  24 #include "pack-test-1.h"
  25
  26 /* Save original alignment values.  Can't use const ints because they
  27    won't be expanded and we'll get bogus errors about variable length
  28    arrays.  (Possible bug in C front end?)  Use s0, not SNAME, so these
  29    won't change later.  */
  30 #define al1 gap(s0, f1, f0)
  31 #define al2 gap(s0, f2, f1)
  32 #define al3 gap(s0, f3, f2)
  33 #define al4 gap(s0, f4, f3)
  34 #define al5 gap(s0, f5, f4)
  35 #define al6 gap(s0, f6, f5)
  36 #define al7 gap(s0, f7, f6)
  37
  38 #undef SNAME
  39 #define SNAME s1
  40 #pragma pack(push, p1, 1)
  41 #include "pack-test-1.h"
  42
  43 void SNAME() {
  44   testgap(0, f1, f0, sizeof(char));
  45   testgap(1, f3, f2, sizeof(short));
  46   testgap(2, f5, f4, sizeof(int));
  47 }
  48
  49 #undef SNAME
  50 #define SNAME s2
  51 #pragma pack(push, p2, 2)
  52 #include "pack-test-1.h"
  53
  54 void SNAME() {
  55   testgap(0, f1, f0, sizeof(short));
  56   testgap(1, f3, f2, sizeof(short));
  57   testgap(2, f5, f4, sizeof(int));
  58 }
  59
  60 #undef SNAME
  61 #define SNAME s3
  62 #pragma pack(push, p3, 4)
  63 #include "pack-test-1.h"
  64
  65 void SNAME() {
  66   testgap(0, f1, f0, sizeof(int));
  67   testgap(1, f3, f2, sizeof(int));
  68   testgap(2, f5, f4, sizeof(int));
  69 }
  70
  71 #undef SNAME
  72 #define SNAME s4
  73 #pragma pack(pop)
  74 #include "pack-test-1.h"
  75
  76 void SNAME() {
  77   testgap(0, f1, f0, sizeof(short));
  78   testgap(1, f3, f2, sizeof(short));
  79   testgap(2, f5, f4, sizeof(int));
  80 }
  81
  82 #undef SNAME
  83 #define SNAME s5
  84 #pragma pack(pop, p2)
  85 #include "pack-test-1.h"
  86
  87 void SNAME() {
  88   testgap(0, f1, f0, sizeof(char));
  89   testgap(1, f3, f2, sizeof(short));
  90   testgap(2, f5, f4, sizeof(int));
  91 }
  92
  93 #undef SNAME
  94 #define SNAME s6
  95 #pragma pack(pop, p1)
  96 #include "pack-test-1.h"
  97
  98 void SNAME() {
  99   testgap(0, f1, f0, al1);
 100   testgap(1, f3, f2, al3);
 101   testgap(2, f5, f4, al5);
 102 }
 103
 104 #undef SNAME
 105 #define SNAME s7
 106 #pragma pack(1)
 107 #include "pack-test-1.h"
 108
 109 void SNAME() {
 110   testgap(0, f1, f0, sizeof(char));
 111   testgap(1, f3, f2, sizeof(short));
 112   testgap(2, f5, f4, sizeof(int));
 113 }
 114
 115 #undef SNAME
 116 #define SNAME s8
 117 #pragma pack(push, p2, 2)
 118 #include "pack-test-1.h"
 119
 120 void SNAME() {
 121   testgap(0, f1, f0, sizeof(short));
 122   testgap(1, f3, f2, sizeof(short));
 123   testgap(2, f5, f4, sizeof(int));
 124 }
 125
 126 #undef SNAME
 127 #define SNAME s9
 128 #pragma pack(pop)
 129 #include "pack-test-1.h"
 130
 131 void SNAME() {
 132   testgap(0, f1, f0, sizeof(char));
 133   testgap(1, f3, f2, sizeof(short));
 134   testgap(2, f5, f4, sizeof(int));
 135 }
 136
 137 #undef SNAME
 138 #define SNAME s10
 139 #pragma pack()
 140 #include "pack-test-1.h"
 141
 142 void SNAME() {
 143   testgap(0, f1, f0, al1);
 144   testgap(1, f3, f2, al3);
 145   testgap(2, f5, f4, al5);
 146 }