/Modules/_ctypes/libffi_osx/ffi.c

  1/* -----------------------------------------------------------------------
  2   prep_cif.c - Copyright (c) 1996, 1998  Red Hat, Inc.
  3
  4   Permission is hereby granted, free of charge, to any person obtaining
  5   a copy of this software and associated documentation files (the
  6   ``Software''), to deal in the Software without restriction, including
  7   without limitation the rights to use, copy, modify, merge, publish,
  8   distribute, sublicense, and/or sell copies of the Software, and to
  9   permit persons to whom the Software is furnished to do so, subject to
 10   the following conditions:
 11
 12   The above copyright notice and this permission notice shall be included
 13   in all copies or substantial portions of the Software.
 14
 15   THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, EXPRESS
 16   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 17   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 18   IN NO EVENT SHALL CYGNUS SOLUTIONS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 19   OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 20   ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 21   OTHER DEALINGS IN THE SOFTWARE.
 22   ----------------------------------------------------------------------- */
 23
 24#include <ffi.h>
 25#include <ffi_common.h>
 26
 27#include <stdbool.h>
 28#include <stdlib.h>
 29
 30/* Round up to FFI_SIZEOF_ARG. */
 31#define STACK_ARG_SIZE(x) ALIGN(x, FFI_SIZEOF_ARG)
 32
 33/* Perform machine independent initialization of aggregate type
 34   specifications. */
 35
 36static ffi_status
 37initialize_aggregate(
 38/*@out@*/	ffi_type*	arg)
 39{
 40/*@-usedef@*/
 41
 42	if (arg == NULL || arg->elements == NULL ||
 43		arg->size != 0 || arg->alignment != 0)
 44		return FFI_BAD_TYPEDEF;
 45
 46	ffi_type**	ptr = &(arg->elements[0]);
 47
 48	while ((*ptr) != NULL)
 49	{
 50		if (((*ptr)->size == 0) && (initialize_aggregate(*ptr) != FFI_OK))
 51			return FFI_BAD_TYPEDEF;
 52
 53		/* Perform a sanity check on the argument type */
 54		FFI_ASSERT_VALID_TYPE(*ptr);
 55
 56#ifdef POWERPC_DARWIN
 57		int curalign = (*ptr)->alignment;
 58
 59		if (ptr != &(arg->elements[0]))
 60		{
 61			if (curalign > 4 && curalign != 16)
 62				curalign = 4;
 63		}
 64
 65		arg->size		= ALIGN(arg->size, curalign);
 66		arg->size		+= (*ptr)->size;
 67		arg->alignment	= (arg->alignment > curalign) ? 
 68			arg->alignment : curalign;
 69#else
 70		arg->size		= ALIGN(arg->size, (*ptr)->alignment);
 71		arg->size		+= (*ptr)->size;
 72		arg->alignment	= (arg->alignment > (*ptr)->alignment) ? 
 73			arg->alignment : (*ptr)->alignment;
 74#endif
 75
 76		ptr++;
 77    }
 78
 79  /* Structure size includes tail padding.  This is important for
 80     structures that fit in one register on ABIs like the PowerPC64
 81     Linux ABI that right justify small structs in a register.
 82     It's also needed for nested structure layout, for example
 83     struct A { long a; char b; }; struct B { struct A x; char y; };
 84     should find y at an offset of 2*sizeof(long) and result in a
 85     total size of 3*sizeof(long).  */
 86	arg->size = ALIGN(arg->size, arg->alignment);
 87
 88	if (arg->size == 0)
 89		return FFI_BAD_TYPEDEF;
 90
 91	return FFI_OK;
 92
 93/*@=usedef@*/
 94}
 95
 96#ifndef __CRIS__
 97/* The CRIS ABI specifies structure elements to have byte
 98   alignment only, so it completely overrides this functions,
 99   which assumes "natural" alignment and padding.  */
100
101/* Perform machine independent ffi_cif preparation, then call
102   machine dependent routine. */
103
104#if defined(X86_DARWIN)
105
106static inline bool
107struct_on_stack(
108	int	size)
109{
110	if (size > 8)
111		return true;
112
113	/* This is not what the ABI says, but is what is really implemented */
114	switch (size)
115	{
116		case 1:
117		case 2:
118		case 4:
119		case 8:
120			return false;
121
122		default:
123			return true;
124	}
125}
126
127#endif	// defined(X86_DARWIN)
128
129// Arguments' ffi_type->alignment must be nonzero.
130ffi_status
131ffi_prep_cif(
132/*@out@*/ /*@partial@*/	ffi_cif*		cif, 
133						ffi_abi			abi,
134						unsigned int	nargs, 
135/*@dependent@*/ /*@out@*/ /*@partial@*/ ffi_type*	rtype, 
136/*@dependent@*/			ffi_type**		atypes)
137{
138	if (cif == NULL)
139		return FFI_BAD_TYPEDEF;
140
141	if (abi <= FFI_FIRST_ABI || abi > FFI_DEFAULT_ABI)
142		return FFI_BAD_ABI;
143
144	unsigned int	bytes	= 0;
145	unsigned int	i;
146	ffi_type**		ptr;
147
148	cif->abi = abi;
149	cif->arg_types = atypes;
150	cif->nargs = nargs;
151	cif->rtype = rtype;
152	cif->flags = 0;
153
154	/* Initialize the return type if necessary */
155	/*@-usedef@*/
156	if ((cif->rtype->size == 0) && (initialize_aggregate(cif->rtype) != FFI_OK))
157		return FFI_BAD_TYPEDEF;
158	/*@=usedef@*/
159
160	/* Perform a sanity check on the return type */
161	FFI_ASSERT_VALID_TYPE(cif->rtype);
162
163	/* x86-64 and s390 stack space allocation is handled in prep_machdep.  */
164#if !defined M68K && !defined __x86_64__ && !defined S390 && !defined PA
165	/* Make space for the return structure pointer */
166	if (cif->rtype->type == FFI_TYPE_STRUCT
167#ifdef SPARC
168		&& (cif->abi != FFI_V9 || cif->rtype->size > 32)
169#endif
170#ifdef X86_DARWIN
171		&& (struct_on_stack(cif->rtype->size))
172#endif
173		)
174		bytes = STACK_ARG_SIZE(sizeof(void*));
175#endif
176
177	for (ptr = cif->arg_types, i = cif->nargs; i > 0; i--, ptr++)
178	{
179		/* Initialize any uninitialized aggregate type definitions */
180		if (((*ptr)->size == 0) && (initialize_aggregate((*ptr)) != FFI_OK))
181			return FFI_BAD_TYPEDEF;
182
183		if ((*ptr)->alignment == 0)
184			return FFI_BAD_TYPEDEF;
185
186		/* Perform a sanity check on the argument type, do this 
187		check after the initialization.  */
188		FFI_ASSERT_VALID_TYPE(*ptr);
189
190#if defined(X86_DARWIN)
191		{
192			int align = (*ptr)->alignment;
193
194			if (align > 4)
195				align = 4;
196
197			if ((align - 1) & bytes)
198				bytes = ALIGN(bytes, align);
199
200			bytes += STACK_ARG_SIZE((*ptr)->size);
201		}
202#elif !defined __x86_64__ && !defined S390 && !defined PA
203#ifdef SPARC
204		if (((*ptr)->type == FFI_TYPE_STRUCT
205			&& ((*ptr)->size > 16 || cif->abi != FFI_V9))
206			|| ((*ptr)->type == FFI_TYPE_LONGDOUBLE
207			&& cif->abi != FFI_V9))
208				bytes += sizeof(void*);
209		else
210#endif
211		{
212			/* Add any padding if necessary */
213			if (((*ptr)->alignment - 1) & bytes)
214				bytes = ALIGN(bytes, (*ptr)->alignment);
215
216			bytes += STACK_ARG_SIZE((*ptr)->size);
217		}
218#endif
219	}
220
221	cif->bytes = bytes;
222
223	/* Perform machine dependent cif processing */
224	return ffi_prep_cif_machdep(cif);
225}
226#endif /* not __CRIS__ */