xref: /external/python/cpython2/Modules/_ctypes/libffi_msvc/prep_cif.c

/* -----------------------------------------------------------------------
   prep_cif.c - Copyright (c) 1996, 1998  Red Hat, Inc.

   Permission is hereby granted, free of charge, to any person obtaining
   a copy of this software and associated documentation files (the
   ``Software''), to deal in the Software without restriction, including
   without limitation the rights to use, copy, modify, merge, publish,
   distribute, sublicense, and/or sell copies of the Software, and to
   permit persons to whom the Software is furnished to do so, subject to
   the following conditions:

   The above copyright notice and this permission notice shall be included
   in all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, EXPRESS
   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
   IN NO EVENT SHALL CYGNUS SOLUTIONS BE LIABLE FOR ANY CLAIM, DAMAGES OR
   OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
   ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   OTHER DEALINGS IN THE SOFTWARE.
   ----------------------------------------------------------------------- */

#include <ffi.h>
#include <ffi_common.h>
#include <stdlib.h>


/* Round up to FFI_SIZEOF_ARG. */

#define STACK_ARG_SIZE(x) ALIGN(x, FFI_SIZEOF_ARG)

/* Perform machine independent initialization of aggregate type
   specifications. */

static ffi_status initialize_aggregate(/*@out@*/ ffi_type *arg)
{
  ffi_type **ptr;

  FFI_ASSERT(arg != NULL);

  /*@-usedef@*/

  FFI_ASSERT(arg->elements != NULL);
  FFI_ASSERT(arg->size == 0);
  FFI_ASSERT(arg->alignment == 0);

  ptr = &(arg->elements[0]);

  while ((*ptr) != NULL)
    {
      if (((*ptr)->size == 0) && (initialize_aggregate((*ptr)) != FFI_OK))
	return FFI_BAD_TYPEDEF;

      /* Perform a sanity check on the argument type */
      FFI_ASSERT_VALID_TYPE(*ptr);

      arg->size = ALIGN(arg->size, (*ptr)->alignment);
      arg->size += (*ptr)->size;

      arg->alignment = (arg->alignment > (*ptr)->alignment) ?
	arg->alignment : (*ptr)->alignment;

      ptr++;
    }

  /* Structure size includes tail padding.  This is important for
     structures that fit in one register on ABIs like the PowerPC64
     Linux ABI that right justify small structs in a register.
     It's also needed for nested structure layout, for example
     struct A { long a; char b; }; struct B { struct A x; char y; };
     should find y at an offset of 2*sizeof(long) and result in a
     total size of 3*sizeof(long).  */
  arg->size = ALIGN (arg->size, arg->alignment);

  if (arg->size == 0)
    return FFI_BAD_TYPEDEF;
  else
    return FFI_OK;

  /*@=usedef@*/
}

/* Perform machine independent ffi_cif preparation, then call
   machine dependent routine. */

ffi_status ffi_prep_cif(/*@out@*/ /*@partial@*/ ffi_cif *cif,
			ffi_abi abi, unsigned int nargs,
			/*@dependent@*/ /*@out@*/ /*@partial@*/ ffi_type *rtype,
			/*@dependent@*/ ffi_type **atypes)
{
  unsigned bytes = 0;
  unsigned int i;
  ffi_type **ptr;

  FFI_ASSERT(cif != NULL);
  FFI_ASSERT((abi > FFI_FIRST_ABI) && (abi <= FFI_DEFAULT_ABI));

  cif->abi = abi;
  cif->arg_types = atypes;
  cif->nargs = nargs;
  cif->rtype = rtype;

  cif->flags = 0;

  /* Initialize the return type if necessary */
  /*@-usedef@*/
  if ((cif->rtype->size == 0) && (initialize_aggregate(cif->rtype) != FFI_OK))
    return FFI_BAD_TYPEDEF;
  /*@=usedef@*/

  /* Perform a sanity check on the return type */
  FFI_ASSERT_VALID_TYPE(cif->rtype);

  /* x86-64 and s390 stack space allocation is handled in prep_machdep.  */
#if !defined M68K && !defined __x86_64__ && !defined S390
  /* Make space for the return structure pointer */
  if (cif->rtype->type == FFI_TYPE_STRUCT
#ifdef _WIN32
      && (cif->rtype->size > 8)  /* MSVC returns small structs in registers */
#endif
#ifdef SPARC
      && (cif->abi != FFI_V9 || cif->rtype->size > 32)
#endif
      )
    bytes = STACK_ARG_SIZE(sizeof(void*));
#endif

  for (ptr = cif->arg_types, i = cif->nargs; i > 0; i--, ptr++)
    {

      /* Initialize any uninitialized aggregate type definitions */
      if (((*ptr)->size == 0) && (initialize_aggregate((*ptr)) != FFI_OK))
	return FFI_BAD_TYPEDEF;

      /* Perform a sanity check on the argument type, do this
	 check after the initialization.  */
      FFI_ASSERT_VALID_TYPE(*ptr);

#if !defined __x86_64__ && !defined S390
#ifdef SPARC
      if (((*ptr)->type == FFI_TYPE_STRUCT
	   && ((*ptr)->size > 16 || cif->abi != FFI_V9))
	  || ((*ptr)->type == FFI_TYPE_LONGDOUBLE
	      && cif->abi != FFI_V9))
	  bytes += sizeof(void*);
      else
#elif defined (_WIN64)
      if ((*ptr)->type == FFI_TYPE_STRUCT && ((*ptr)->size > 8))
	    bytes += sizeof(void*);
      else
#endif
	{
#if !defined(_MSC_VER) && !defined(__MINGW32__)
		/* Don't know if this is a libffi bug or not.  At least on
		   Windows with MSVC, function call parameters are *not*
		   aligned in the same way as structure fields are, they are
		   only aligned in integer boundaries.

		   This doesn't do any harm for cdecl functions and closures,
		   since the caller cleans up the stack, but it is wrong for
		   stdcall functions where the callee cleans.
		*/

	  /* Add any padding if necessary */
	  if (((*ptr)->alignment - 1) & bytes)
	    bytes = ALIGN(bytes, (*ptr)->alignment);

#endif
	  bytes += STACK_ARG_SIZE((*ptr)->size);
	}
#endif
    }

#ifdef _WIN64
  /* Function call needs at least 40 bytes stack size, on win64 AMD64 */
  if (bytes < 40)
      bytes = 40;
#endif

  cif->bytes = bytes;

  /* Perform machine dependent cif processing */
  return ffi_prep_cif_machdep(cif);
}