bitfield-5.m

来自「linux下编程用 编译软件」· M 代码 · 共 114 行

/* Check ObjC class layout follows the ABI (informally)
   set in the past.  ObjC structs must be laid out as if
   all ivars, including those inherited from superclasses,
   were defined at once (i.e., any padding introduced for
   superclasses should be removed).  */
/* Contributed by Ziemowit Laski <[e-mail]>.  */
/* { dg-options "-Wpadded" } */
/* { dg-do run } */

#include <objc/objc.h>
#include <objc/Object.h>
#include <stdlib.h>

#define CHECK_IF(expr) if(!(expr)) abort()

enum Enum { zero, one, two, three, four };

@interface Base: Object {
@public
  unsigned a: 2;
  int b: 3;
  enum Enum c: 4;
  unsigned d: 5;
} /* { dg-warning "padding struct size to alignment boundary" } */
@end

struct Base_0 {
  Class isa;
  unsigned a: 2;
  int b: 3;
  enum Enum c: 4;
  unsigned d: 5;
}; /* { dg-warning "padding struct size to alignment boundary" } */

@interface Derived: Base {
@public
  signed e: 5;
  unsigned f: 4;
  enum Enum g: 3;
} /* { dg-warning "padding struct size to alignment boundary" } */
@end

struct Derived_0 {
  Class isa;
  unsigned a: 2;
  int b: 3;
  enum Enum c: 4;
  unsigned d: 5;
  signed e: 5;
  int f: 4;
  enum Enum g: 3;
}; /* { dg-warning "padding struct size to alignment boundary" } */

@interface Leaf: Derived {
@public
  signed h: 2;
} /* { dg-warning "padding struct size to alignment boundary" } */
@end

struct Leaf_0 {
  Class isa;
  unsigned a: 2;
  int b: 3;
  enum Enum c: 4;
  unsigned d: 5;
  signed e: 5;
  unsigned f: 4;
  enum Enum g: 3;
  signed h: 2;
}; /* { dg-warning "padding struct size to alignment boundary" } */
  
/* Note that the semicolon after @defs(...) is optional.  */

typedef struct { @defs(Base) } Base_t;  /* { dg-warning "padding struct size to alignment boundary" } */
typedef struct { @defs(Derived); } Derived_t;  /* { dg-warning "padding struct size to alignment boundary" } */
typedef struct { @defs(Leaf); } Leaf_t;  /* { dg-warning "padding struct size to alignment boundary" } */

int main(void)
{
  struct Leaf_0 l_0;
  Leaf *l = (Leaf *)&l_0;
  Leaf_t *l_t = (Leaf_t *)&l_0;

  CHECK_IF(sizeof(Base_t) == sizeof(Base));
  CHECK_IF(sizeof(Derived_t) == sizeof(Derived));
  CHECK_IF(sizeof(Leaf_t) == sizeof(Leaf));

  CHECK_IF(sizeof(struct Base_0) == sizeof(Base));
  CHECK_IF(sizeof(struct Derived_0) == sizeof(Derived));
  CHECK_IF(sizeof(struct Leaf_0) == sizeof(Leaf));

  l_0.isa = (Class)0;
  l_0.a = 3;
  l_0.b = 0;
  l_0.c = three;
  l_0.d = 31;
  l_0.e = 0;
  l_0.f = 15;
  l_0.g = zero;
  l_0.h = -2;

  CHECK_IF(!l_t->isa);
  CHECK_IF(l->a == 3 && l_t->a == 3);
  CHECK_IF(!l->b && !l_t->b);
  CHECK_IF(l->c == three && l_t->c == three);
  CHECK_IF(l->d == 31 && l_t->d == 31);
  CHECK_IF(!l->e && !l_t->e);
  CHECK_IF(l->f == 15 && l_t->f == 15);
  CHECK_IF(l->g == zero && l_t->g == zero);
  CHECK_IF(l->h == -2 && l_t->h == -2);
  
  return 0;
}