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iitialisation of the empty struct

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Current tcc don't understand an initialization of the empty struct
This problem was found trying to compile a linux kernel 2.4.26
which can be compiled by tcc 0.9.23

  A test program:
  ////////////////////
  // ./tcc -c test_3.c
  // test_3.c:31: error: too many field init
  #undef __GNUC__
  #undef __GNUC_MINOR__
  #define __GNUC__  2
  #define __GNUC_MINOR__ 95
  typedef struct { } rwlock_t;
  struct fs_struct {
   int count;
   rwlock_t lock;
   int umask;
  };
  #define INIT_FS { \
	1, \
	RW_LOCK_UNLOCKED, \
	0022, \
  }
  #if (__GNUC__ > 2 || __GNUC_MINOR__ > 91)
    typedef struct { } rwlock_t;
    #define RW_LOCK_UNLOCKED (rwlock_t) { }
  #else
    typedef struct { int gcc_is_buggy; } rwlock_t;
    #define RW_LOCK_UNLOCKED (rwlock_t) { 0 }
  #endif
  static struct fs_struct init_fs = INIT_FS;
  // static struct fs_struct init_fs = { { (1) }, (rwlock_t) { 0 }, 0022, };
  //                                                           ^ with this all Ok
  // static struct fs_struct init_fs = { { (1) }, (rwlock_t) { }, 0022, };
  //                                                          ^ current tcc don't understand, but tcc 0.9.23 can
  int main()
  {
    return 0;
  }
  ////////////////////
  A regression is detected after a patch 69fdb57edd
  ////////////////////
  // A test for patch 69fdb57edd
  // Author: grischka <grischka>
  // Date:   Wed Jun 17 02:09:07 2009 +0200
  //     unions: initzialize only one field
  //         struct {
  //           union {
  //             int a,b;
  //           };
  //           int c;
  //         } sss = { 1,2 };
  //     This had previously assigned 1,2 to a,b and 0 to c which is wrong.
  //
  // Expected: sss.a=1 sss.b=1 sss.c=2
  int main()
  {
    struct {
      union {
        int a,b;
      };
      int c;
    } sss = { 1, 2 };

    printf ("sss.a=%d sss.b=%d sss.c=%d\n", sss.a, sss.b, sss.c);
    return 0;
  }
  ////////////////////
This commit is contained in:
seyko 2015-03-03 15:15:48 +03:00
parent bbf8221ec3
commit 1a1e9548fb
1 changed files with 20 additions and 0 deletions
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20
tccgen.c
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@ -5525,10 +5525,30 @@ static void decl_initializer(CType *type, Section *sec, unsigned long c,
/* gr: skip fields from same union - ugly. */
while (f->next) {
int align = 0;
int f_size = type_size(&f->type, &align);
int f_type = (f->type.t & VT_BTYPE);
///printf("index: %2d %08x -- %2d %08x\n", f->c, f->type.t, f->next->c, f->next->type.t);
/* test for same offset */
if (f->next->c != f->c)
break;
if ((f_type == VT_STRUCT) && (f_size == 0)) {
/*
Lets assume a structure of size 0 can't be a member of the union.
This allow to compile the following code from a linux kernel v2.4.26
typedef struct { } rwlock_t;
struct fs_struct {
int count;
rwlock_t lock;
int umask;
};
struct fs_struct init_fs = { { (1) }, (rwlock_t) {}, 0022, };
tcc-0.9.23 can succesfully compile this version of the kernel.
gcc don't have problems with this code too.
*/
break;
}
/* if yes, test for bitfield shift */
if ((f->type.t & VT_BITFIELD) && (f->next->type.t & VT_BITFIELD)) {
int bit_pos_1 = (f->type.t >> VT_STRUCT_SHIFT) & 0x3f;