github.com/prattmic/llgo-embedded@v0.0.0-20150820070356-41cfecea0e1e/third_party/gofrontend/libffi/src/powerpc/ffi.c

/* -----------------------------------------------------------------------
   ffi.c - Copyright (C) 2013 IBM
           Copyright (C) 2011 Anthony Green
           Copyright (C) 2011 Kyle Moffett
           Copyright (C) 2008 Red Hat, Inc
           Copyright (C) 2007, 2008 Free Software Foundation, Inc
	   Copyright (c) 1998 Geoffrey Keating

   PowerPC Foreign Function Interface

   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 THE AUTHOR 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 "ffi_powerpc.h"

#if HAVE_LONG_DOUBLE_VARIANT
/* Adjust ffi_type_longdouble.  */
void FFI_HIDDEN
ffi_prep_types (ffi_abi abi)
{
# if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
#  ifdef POWERPC64
  ffi_prep_types_linux64 (abi);
#  else
  ffi_prep_types_sysv (abi);
#  endif
# endif
}
#endif

/* Perform machine dependent cif processing */
ffi_status FFI_HIDDEN
ffi_prep_cif_machdep (ffi_cif *cif)
{
#ifdef POWERPC64
  return ffi_prep_cif_linux64 (cif);
#else
  return ffi_prep_cif_sysv (cif);
#endif
}

ffi_status FFI_HIDDEN
ffi_prep_cif_machdep_var (ffi_cif *cif,
			  unsigned int nfixedargs MAYBE_UNUSED,
			  unsigned int ntotalargs MAYBE_UNUSED)
{
#ifdef POWERPC64
  return ffi_prep_cif_linux64_var (cif, nfixedargs, ntotalargs);
#else
  return ffi_prep_cif_sysv (cif);
#endif
}

static void
ffi_call_int (ffi_cif *cif,
	      void (*fn) (void),
	      void *rvalue,
	      void **avalue,
	      void *closure)
{
  /* The final SYSV ABI says that structures smaller or equal 8 bytes
     are returned in r3/r4.  A draft ABI used by linux instead returns
     them in memory.

     We bounce-buffer SYSV small struct return values so that sysv.S
     can write r3 and r4 to memory without worrying about struct size.
   
     For ELFv2 ABI, use a bounce buffer for homogeneous structs too,
     for similar reasons.  */
  unsigned long smst_buffer[8];
  extended_cif ecif;

  ecif.cif = cif;
  ecif.avalue = avalue;

  ecif.rvalue = rvalue;
  if ((cif->flags & FLAG_RETURNS_SMST) != 0)
    ecif.rvalue = smst_buffer;
  /* Ensure that we have a valid struct return value.
     FIXME: Isn't this just papering over a user problem?  */
  else if (!rvalue && cif->rtype->type == FFI_TYPE_STRUCT)
    ecif.rvalue = alloca (cif->rtype->size);

#ifdef POWERPC64
  ffi_call_LINUX64 (&ecif, fn, ecif.rvalue, cif->flags, closure,
		    -(long) cif->bytes);
#else
  ffi_call_SYSV (&ecif, fn, ecif.rvalue, cif->flags, closure, -cif->bytes);
#endif

  /* Check for a bounce-buffered return value */
  if (rvalue && ecif.rvalue == smst_buffer)
    {
      unsigned int rsize = cif->rtype->size;
#ifndef __LITTLE_ENDIAN__
      /* The SYSV ABI returns a structure of up to 4 bytes in size
	 left-padded in r3.  */
# ifndef POWERPC64
      if (rsize <= 4)
	memcpy (rvalue, (char *) smst_buffer + 4 - rsize, rsize);
      else
# endif
	/* The SYSV ABI returns a structure of up to 8 bytes in size
	   left-padded in r3/r4, and the ELFv2 ABI similarly returns a
	   structure of up to 8 bytes in size left-padded in r3.  */
	if (rsize <= 8)
	  memcpy (rvalue, (char *) smst_buffer + 8 - rsize, rsize);
	else
#endif
	  memcpy (rvalue, smst_buffer, rsize);
    }
}

void
ffi_call (ffi_cif *cif, void (*fn) (void), void *rvalue, void **avalue)
{
  ffi_call_int (cif, fn, rvalue, avalue, NULL);
}

void
ffi_call_go (ffi_cif *cif, void (*fn) (void), void *rvalue, void **avalue,
	     void *closure)
{
  ffi_call_int (cif, fn, rvalue, avalue, closure);
}

ffi_status
ffi_prep_closure_loc (ffi_closure *closure,
		      ffi_cif *cif,
		      void (*fun) (ffi_cif *, void *, void **, void *),
		      void *user_data,
		      void *codeloc)
{
#ifdef POWERPC64
  return ffi_prep_closure_loc_linux64 (closure, cif, fun, user_data, codeloc);
#else
  return ffi_prep_closure_loc_sysv (closure, cif, fun, user_data, codeloc);
#endif
}

ffi_status
ffi_prep_go_closure (ffi_go_closure *closure,
		     ffi_cif *cif,
		     void (*fun) (ffi_cif *, void *, void **, void *))
{
#ifdef POWERPC64
  closure->tramp = ffi_go_closure_linux64;
#else
  closure->tramp = ffi_go_closure_sysv;
#endif
  closure->cif = cif;
  closure->fun = fun;
  return FFI_OK;
}