ffi.c

gcc的组建

      case FFI_TYPE_SINT32:
      case FFI_TYPE_UINT16:
      case FFI_TYPE_SINT16:
      case FFI_TYPE_UINT8:
      case FFI_TYPE_SINT8:
	/* These are to be extended to word size.  */
#ifdef __s390x__
	cif->flags = FFI390_RET_INT64;
#else
	cif->flags = FFI390_RET_INT32;
#endif
	break;
 
      default:
        FFI_ASSERT (0);
        break;
    }

  /* Now for the arguments.  */
 
  for (ptr = cif->arg_types, i = cif->nargs;
       i > 0;
       i--, ptr++)
    {
      int type = (*ptr)->type;

      /* Check how a structure type is passed.  */
      if (type == FFI_TYPE_STRUCT)
	{
	  type = ffi_check_struct_type (*ptr);

	  /* If we pass the struct via pointer, we must reserve space
	     to copy its data for proper call-by-value semantics.  */
	  if (type == FFI_TYPE_POINTER)
	    struct_size += ROUND_SIZE ((*ptr)->size);
	}

      /* Now handle all primitive int/float data types.  */
      switch (type) 
	{
	  /* The first MAX_FPRARGS floating point arguments
	     go in FPRs, the rest overflow to the stack.  */

	  case FFI_TYPE_DOUBLE:
	    if (n_fpr < MAX_FPRARGS)
	      n_fpr++;
	    else
	      n_ov += sizeof (double) / sizeof (long);
	    break;
	
	  case FFI_TYPE_FLOAT:
	    if (n_fpr < MAX_FPRARGS)
	      n_fpr++;
	    else
	      n_ov++;
	    break;

	  /* On 31-bit machines, 64-bit integers are passed in GPR pairs,
	     if one is still available, or else on the stack.  If only one
	     register is free, skip the register (it won't be used for any 
	     subsequent argument either).  */
	      
#ifndef __s390x__
	  case FFI_TYPE_UINT64:
	  case FFI_TYPE_SINT64:
	    if (n_gpr == MAX_GPRARGS-1)
	      n_gpr = MAX_GPRARGS;
	    if (n_gpr < MAX_GPRARGS)
	      n_gpr += 2;
	    else
	      n_ov += 2;
	    break;
#endif

	  /* Everything else is passed in GPRs (until MAX_GPRARGS
	     have been used) or overflows to the stack.  */

	  default: 
	    if (n_gpr < MAX_GPRARGS)
	      n_gpr++;
	    else
	      n_ov++;
	    break;
        }
    }

  /* Total stack space as required for overflow arguments
     and temporary structure copies.  */

  cif->bytes = ROUND_SIZE (n_ov * sizeof (long)) + struct_size;
 
  return FFI_OK;
}
 
/*======================== End of Routine ============================*/
 
/*====================================================================*/
/*                                                                    */
/* Name     - ffi_call.                                               */
/*                                                                    */
/* Function - Call the FFI routine.                                   */
/*                                                                    */
/*====================================================================*/
 
void
ffi_call(ffi_cif *cif,
	 void (*fn)(),
	 void *rvalue,
	 void **avalue)
{
  int ret_type = cif->flags;
  extended_cif ecif;
 
  ecif.cif    = cif;
  ecif.avalue = avalue;
  ecif.rvalue = rvalue;

  /* If we don't have a return value, we need to fake one.  */
  if (rvalue == NULL)
    {
      if (ret_type == FFI390_RET_STRUCT)
	ecif.rvalue = alloca (cif->rtype->size);
      else
	ret_type = FFI390_RET_VOID;
    } 

  switch (cif->abi)
    {
      case FFI_SYSV:
        ffi_call_SYSV (cif->bytes, &ecif, ffi_prep_args,
		       ret_type, ecif.rvalue, fn);
        break;
 
      default:
        FFI_ASSERT (0);
        break;
    }
}
 
/*======================== End of Routine ============================*/

/*====================================================================*/
/*                                                                    */
/* Name     - ffi_closure_helper_SYSV.                                */
/*                                                                    */
/* Function - Call a FFI closure target function.                     */
/*                                                                    */
/*====================================================================*/
 
void
ffi_closure_helper_SYSV (ffi_closure *closure,
			 unsigned long *p_gpr,
			 unsigned long long *p_fpr,
			 unsigned long *p_ov)
{
  unsigned long long ret_buffer;

  void *rvalue = &ret_buffer;
  void **avalue;
  void **p_arg;

  int n_gpr = 0;
  int n_fpr = 0;
  int n_ov = 0;

  ffi_type **ptr;
  int i;

  /* Allocate buffer for argument list pointers.  */

  p_arg = avalue = alloca (closure->cif->nargs * sizeof (void *));

  /* If we returning a structure, pass the structure address 
     directly to the target function.  Otherwise, have the target 
     function store the return value to the GPR save area.  */

  if (closure->cif->flags == FFI390_RET_STRUCT)
    rvalue = (void *) p_gpr[n_gpr++];

  /* Now for the arguments.  */

  for (ptr = closure->cif->arg_types, i = closure->cif->nargs;
       i > 0;
       i--, p_arg++, ptr++)
    {
      int deref_struct_pointer = 0;
      int type = (*ptr)->type;

      /* Check how a structure type is passed.  */
      if (type == FFI_TYPE_STRUCT)
	{
	  type = ffi_check_struct_type (*ptr);

	  /* If we pass the struct via pointer, remember to 
	     retrieve the pointer later.  */
	  if (type == FFI_TYPE_POINTER)
	    deref_struct_pointer = 1;
	}

      /* Pointers are passed like UINTs of the same size.  */
      if (type == FFI_TYPE_POINTER)
#ifdef __s390x__
	type = FFI_TYPE_UINT64;
#else
	type = FFI_TYPE_UINT32;
#endif

      /* Now handle all primitive int/float data types.  */
      switch (type) 
	{
	  case FFI_TYPE_DOUBLE:
	    if (n_fpr < MAX_FPRARGS)
	      *p_arg = &p_fpr[n_fpr++];
	    else
	      *p_arg = &p_ov[n_ov], 
	      n_ov += sizeof (double) / sizeof (long);
	    break;
	
	  case FFI_TYPE_FLOAT:
	    if (n_fpr < MAX_FPRARGS)
	      *p_arg = &p_fpr[n_fpr++];
	    else
	      *p_arg = (char *)&p_ov[n_ov++] + sizeof (long) - 4;
	    break;
 
	  case FFI_TYPE_UINT64:
	  case FFI_TYPE_SINT64:
#ifdef __s390x__
	    if (n_gpr < MAX_GPRARGS)
	      *p_arg = &p_gpr[n_gpr++];
	    else
	      *p_arg = &p_ov[n_ov++];
#else
	    if (n_gpr == MAX_GPRARGS-1)
	      n_gpr = MAX_GPRARGS;
	    if (n_gpr < MAX_GPRARGS)
	      *p_arg = &p_gpr[n_gpr], n_gpr += 2;
	    else
	      *p_arg = &p_ov[n_ov], n_ov += 2;
#endif
	    break;
 
	  case FFI_TYPE_INT:
	  case FFI_TYPE_UINT32:
	  case FFI_TYPE_SINT32:
	    if (n_gpr < MAX_GPRARGS)
	      *p_arg = (char *)&p_gpr[n_gpr++] + sizeof (long) - 4;
	    else
	      *p_arg = (char *)&p_ov[n_ov++] + sizeof (long) - 4;
	    break;
 
	  case FFI_TYPE_UINT16:
	  case FFI_TYPE_SINT16:
	    if (n_gpr < MAX_GPRARGS)
	      *p_arg = (char *)&p_gpr[n_gpr++] + sizeof (long) - 2;
	    else
	      *p_arg = (char *)&p_ov[n_ov++] + sizeof (long) - 2;
	    break;

	  case FFI_TYPE_UINT8:
	  case FFI_TYPE_SINT8:
	    if (n_gpr < MAX_GPRARGS)
	      *p_arg = (char *)&p_gpr[n_gpr++] + sizeof (long) - 1;
	    else
	      *p_arg = (char *)&p_ov[n_ov++] + sizeof (long) - 1;
	    break;
 
	  default:
	    FFI_ASSERT (0);
	    break;
        }

      /* If this is a struct passed via pointer, we need to
	 actually retrieve that pointer.  */
      if (deref_struct_pointer)
	*p_arg = *(void **)*p_arg;
    }


  /* Call the target function.  */
  (closure->fun) (closure->cif, rvalue, avalue, closure->user_data);

  /* Convert the return value.  */
  switch (closure->cif->rtype->type)
    {
      /* Void is easy, and so is struct.  */
      case FFI_TYPE_VOID:
      case FFI_TYPE_STRUCT:
	break;

      /* Floating point values are returned in fpr 0.  */
      case FFI_TYPE_FLOAT:
	p_fpr[0] = (long long) *(unsigned int *) rvalue << 32;
	break;

      case FFI_TYPE_DOUBLE:
	p_fpr[0] = *(unsigned long long *) rvalue;
	break;

      /* Integer values are returned in gpr 2 (and gpr 3
	 for 64-bit values on 31-bit machines).  */
      case FFI_TYPE_UINT64:
      case FFI_TYPE_SINT64:
#ifdef __s390x__
	p_gpr[0] = *(unsigned long *) rvalue;
#else
	p_gpr[0] = ((unsigned long *) rvalue)[0],
	p_gpr[1] = ((unsigned long *) rvalue)[1];
#endif
	break;

      case FFI_TYPE_POINTER:
      case FFI_TYPE_UINT32:
      case FFI_TYPE_UINT16:
      case FFI_TYPE_UINT8:
	p_gpr[0] = *(unsigned long *) rvalue;
	break;

      case FFI_TYPE_INT:
      case FFI_TYPE_SINT32:
      case FFI_TYPE_SINT16:
      case FFI_TYPE_SINT8:
	p_gpr[0] = *(signed long *) rvalue;
	break;

      default:
        FFI_ASSERT (0);
        break;
    }
}
 
/*======================== End of Routine ============================*/

/*====================================================================*/
/*                                                                    */
/* Name     - ffi_prep_closure.                                       */
/*                                                                    */
/* Function - Prepare a FFI closure.                                  */
/*                                                                    */
/*====================================================================*/
 
ffi_status
ffi_prep_closure (ffi_closure *closure,
                  ffi_cif *cif,
                  void (*fun) (ffi_cif *, void *, void **, void *),
                  void *user_data)
{
  FFI_ASSERT (cif->abi == FFI_SYSV);

#ifndef __s390x__
  *(short *)&closure->tramp [0] = 0x0d10;   /* basr %r1,0 */
  *(short *)&closure->tramp [2] = 0x9801;   /* lm %r0,%r1,6(%r1) */
  *(short *)&closure->tramp [4] = 0x1006;
  *(short *)&closure->tramp [6] = 0x07f1;   /* br %r1 */
  *(long  *)&closure->tramp [8] = (long)closure;
  *(long  *)&closure->tramp[12] = (long)&ffi_closure_SYSV;
#else
  *(short *)&closure->tramp [0] = 0x0d10;   /* basr %r1,0 */
  *(short *)&closure->tramp [2] = 0xeb01;   /* lmg %r0,%r1,14(%r1) */
  *(short *)&closure->tramp [4] = 0x100e;
  *(short *)&closure->tramp [6] = 0x0004;
  *(short *)&closure->tramp [8] = 0x07f1;   /* br %r1 */
  *(long  *)&closure->tramp[16] = (long)closure;
  *(long  *)&closure->tramp[24] = (long)&ffi_closure_SYSV;
#endif 
 
  closure->cif = cif;
  closure->user_data = user_data;
  closure->fun = fun;
 
  return FFI_OK;
}

/*======================== End of Routine ============================*/