src/alpha/ffi.c

/* -----------------------------------------------------------------------
   ffi.c - Copyright (c) 2012  Anthony Green
	   Copyright (c) 1998, 2001, 2007, 2008  Red Hat, Inc.

   Alpha 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 AUTHORS OR COPYRIGHT
   HOLDERS 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>
#include "internal.h"

/* Force FFI_TYPE_LONGDOUBLE to be different than FFI_TYPE_DOUBLE;
   all further uses in this file will refer to the 128-bit type.  */
#if defined(__LONG_DOUBLE_128__)
# if FFI_TYPE_LONGDOUBLE != 4
#  error FFI_TYPE_LONGDOUBLE out of date
# endif
#else
# undef FFI_TYPE_LONGDOUBLE
# define FFI_TYPE_LONGDOUBLE 4
#endif

extern void ffi_call_osf(void *stack, void *frame, unsigned flags,
			 void *raddr, void (*fn)(void), void *closure)
	FFI_HIDDEN;
extern void ffi_closure_osf(void) FFI_HIDDEN;
extern void ffi_go_closure_osf(void) FFI_HIDDEN;

/* Promote a float value to its in-register double representation.
   Unlike actually casting to double, this does not trap on NaN.  */
static inline UINT64 lds(void *ptr)
{
  UINT64 ret;
  asm("lds %0,%1" : "=f"(ret) : "m"(*(UINT32 *)ptr));
  return ret;
}

/* And the reverse.  */
static inline void sts(void *ptr, UINT64 val)
{
  asm("sts %1,%0" : "=m"(*(UINT32 *)ptr) : "f"(val));
}

ffi_status FFI_HIDDEN
ffi_prep_cif_machdep(ffi_cif *cif)
{
  size_t bytes = 0;
  int flags, i, avn;
  ffi_type *rtype, *itype;

  if (cif->abi != FFI_OSF)
    return FFI_BAD_ABI;

  /* Compute the size of the argument area.  */
  for (i = 0, avn = cif->nargs; i < avn; i++)
    {
      itype = cif->arg_types[i];
      switch (itype->type)
	{
	case FFI_TYPE_INT:
	case FFI_TYPE_SINT8:
	case FFI_TYPE_UINT8:
	case FFI_TYPE_SINT16:
	case FFI_TYPE_UINT16:
	case FFI_TYPE_SINT32:
	case FFI_TYPE_UINT32:
	case FFI_TYPE_SINT64:
	case FFI_TYPE_UINT64:
	case FFI_TYPE_POINTER:
	case FFI_TYPE_FLOAT:
	case FFI_TYPE_DOUBLE:
	case FFI_TYPE_LONGDOUBLE:
	  /* All take one 8 byte slot.  */
	  bytes += 8;
	  break;

	case FFI_TYPE_VOID:
	case FFI_TYPE_STRUCT:
	  /* Passed by value in N slots.  */
	  bytes += FFI_ALIGN(itype->size, FFI_SIZEOF_ARG);
	  break;

	case FFI_TYPE_COMPLEX:
	  /* _Complex long double passed by reference; others in 2 slots.  */
	  if (itype->elements[0]->type == FFI_TYPE_LONGDOUBLE)
	    bytes += 8;
	  else
	    bytes += 16;
	  break;

	default:
	  abort();
	}
    }

  /* Set the return type flag */
  rtype = cif->rtype;
  switch (rtype->type)
    {
    case FFI_TYPE_VOID:
      flags = ALPHA_FLAGS(ALPHA_ST_VOID, ALPHA_LD_VOID);
      break;
    case FFI_TYPE_INT:
    case FFI_TYPE_UINT32:
    case FFI_TYPE_SINT32:
      flags = ALPHA_FLAGS(ALPHA_ST_INT, ALPHA_LD_INT32);
      break;
    case FFI_TYPE_FLOAT:
      flags = ALPHA_FLAGS(ALPHA_ST_FLOAT, ALPHA_LD_FLOAT);
      break;
    case FFI_TYPE_DOUBLE:
      flags = ALPHA_FLAGS(ALPHA_ST_DOUBLE, ALPHA_LD_DOUBLE);
      break;
    case FFI_TYPE_UINT8:
      flags = ALPHA_FLAGS(ALPHA_ST_INT, ALPHA_LD_UINT8);
      break;
    case FFI_TYPE_SINT8:
      flags = ALPHA_FLAGS(ALPHA_ST_INT, ALPHA_LD_SINT8);
      break;
    case FFI_TYPE_UINT16:
      flags = ALPHA_FLAGS(ALPHA_ST_INT, ALPHA_LD_UINT16);
      break;
    case FFI_TYPE_SINT16:
      flags = ALPHA_FLAGS(ALPHA_ST_INT, ALPHA_LD_SINT16);
      break;
    case FFI_TYPE_UINT64:
    case FFI_TYPE_SINT64:
    case FFI_TYPE_POINTER:
      flags = ALPHA_FLAGS(ALPHA_ST_INT, ALPHA_LD_INT64);
      break;
    case FFI_TYPE_LONGDOUBLE:
    case FFI_TYPE_STRUCT:
      /* Passed in memory, with a hidden pointer.  */
      flags = ALPHA_RET_IN_MEM;
      break;
    case FFI_TYPE_COMPLEX:
      itype = rtype->elements[0];
      switch (itype->type)
	{
	case FFI_TYPE_FLOAT:
	  flags = ALPHA_FLAGS(ALPHA_ST_CPLXF, ALPHA_LD_CPLXF);
	  break;
	case FFI_TYPE_DOUBLE:
	  flags = ALPHA_FLAGS(ALPHA_ST_CPLXD, ALPHA_LD_CPLXD);
	  break;
	default:
	  if (rtype->size <= 8)
	    flags = ALPHA_FLAGS(ALPHA_ST_INT, ALPHA_LD_INT64);
	  else
	    flags = ALPHA_RET_IN_MEM;
	  break;
	}
      break;
    default:
      abort();
    }
  cif->flags = flags;

  /* Include the hidden structure pointer in args requirement.  */
  if (flags == ALPHA_RET_IN_MEM)
    bytes += 8;
  /* Minimum size is 6 slots, so that ffi_call_osf can pop them.  */
  if (bytes < 6*8)
    bytes = 6*8;
  cif->bytes = bytes;

  return FFI_OK;
}

static unsigned long
extend_basic_type(void *valp, int type, int argn)
{
  switch (type)
    {
    case FFI_TYPE_SINT8:
      return *(SINT8 *)valp;
    case FFI_TYPE_UINT8:
      return *(UINT8 *)valp;
    case FFI_TYPE_SINT16:
      return *(SINT16 *)valp;
    case FFI_TYPE_UINT16:
      return *(UINT16 *)valp;

    case FFI_TYPE_FLOAT:
      if (argn < 6)
	return lds(valp);
      /* FALLTHRU */

    case FFI_TYPE_INT:
    case FFI_TYPE_SINT32:
    case FFI_TYPE_UINT32:
      /* Note that unsigned 32-bit quantities are sign extended.  */
      return *(SINT32 *)valp;

    case FFI_TYPE_SINT64:
    case FFI_TYPE_UINT64:
    case FFI_TYPE_POINTER:
    case FFI_TYPE_DOUBLE:
      return *(UINT64 *)valp;

    default:
      abort();
    }
}

static void
ffi_call_int (ffi_cif *cif, void (*fn)(void), void *rvalue,
	      void **avalue, void *closure)
{
  unsigned long *argp;
  long i, avn, argn, flags = cif->flags;
  ffi_type **arg_types;
  void *frame;

  /* If the return value is a struct and we don't have a return
     value address then we need to make one.  */
  if (rvalue == NULL && flags == ALPHA_RET_IN_MEM)
    rvalue = alloca(cif->rtype->size);

  /* Allocate the space for the arguments, plus 4 words of temp
     space for ffi_call_osf.  */
  argp = frame = alloca(cif->bytes + 4*FFI_SIZEOF_ARG);
  frame += cif->bytes;

  argn = 0;
  if (flags == ALPHA_RET_IN_MEM)
    argp[argn++] = (unsigned long)rvalue;

  avn = cif->nargs;
  arg_types = cif->arg_types;

  for (i = 0, avn = cif->nargs; i < avn; i++)
    {
      ffi_type *ty = arg_types[i];
      void *valp = avalue[i];
      int type = ty->type;
      size_t size;

      switch (type)
	{
	case FFI_TYPE_INT:
	case FFI_TYPE_SINT8:
	case FFI_TYPE_UINT8:
	case FFI_TYPE_SINT16:
	case FFI_TYPE_UINT16:
	case FFI_TYPE_SINT32:
	case FFI_TYPE_UINT32:
	case FFI_TYPE_SINT64:
	case FFI_TYPE_UINT64:
	case FFI_TYPE_POINTER:
	case FFI_TYPE_FLOAT:
	case FFI_TYPE_DOUBLE:
	  argp[argn] = extend_basic_type(valp, type, argn);
	  argn++;
	  break;

	case FFI_TYPE_LONGDOUBLE:
	by_reference:
	  /* Note that 128-bit long double is passed by reference.  */
	  argp[argn++] = (unsigned long)valp;
	  break;

	case FFI_TYPE_VOID:
	case FFI_TYPE_STRUCT:
	  size = ty->size;
	  memcpy(argp + argn, valp, size);
	  argn += FFI_ALIGN(size, FFI_SIZEOF_ARG) / FFI_SIZEOF_ARG;
	  break;

	case FFI_TYPE_COMPLEX:
	  type = ty->elements[0]->type;
	  if (type == FFI_TYPE_LONGDOUBLE)
	    goto by_reference;

	  /* Most complex types passed as two separate arguments.  */
	  size = ty->elements[0]->size;
	  argp[argn] = extend_basic_type(valp, type, argn);
	  argp[argn + 1] = extend_basic_type(valp + size, type, argn + 1);
	  argn += 2;
	  break;

	default:
	  abort();
	}
    }

  flags = (flags >> ALPHA_ST_SHIFT) & 0xff;
  ffi_call_osf(argp, frame, flags, rvalue, fn, closure);
}

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)
{
  unsigned int *tramp;

  if (cif->abi != FFI_OSF)
    return FFI_BAD_ABI;

  tramp = (unsigned int *) &closure->tramp[0];
  tramp[0] = 0x47fb0401;	/* mov $27,$1		*/
  tramp[1] = 0xa77b0010;	/* ldq $27,16($27)	*/
  tramp[2] = 0x6bfb0000;	/* jmp $31,($27),0	*/
  tramp[3] = 0x47ff041f;	/* nop			*/
  *(void **) &tramp[4] = ffi_closure_osf;

  closure->cif = cif;
  closure->fun = fun;
  closure->user_data = user_data;

  /* Flush the Icache.

     Tru64 UNIX as doesn't understand the imb mnemonic, so use call_pal
     instead, since both Compaq as and gas can handle it.

     0x86 is PAL_imb in Tru64 UNIX <alpha/pal.h>.  */
  asm volatile ("call_pal 0x86" : : : "memory");

  return FFI_OK;
}

ffi_status
ffi_prep_go_closure (ffi_go_closure* closure,
		     ffi_cif* cif,
		     void (*fun)(ffi_cif*, void*, void**, void*))
{
  if (cif->abi != FFI_OSF)
    return FFI_BAD_ABI;

  closure->tramp = (void *)ffi_go_closure_osf;
  closure->cif = cif;
  closure->fun = fun;

  return FFI_OK;
}

long FFI_HIDDEN
ffi_closure_osf_inner (ffi_cif *cif,
		       void (*fun)(ffi_cif*, void*, void**, void*),
		       void *user_data,
		       void *rvalue, unsigned long *argp)
{
  void **avalue;
  ffi_type **arg_types;
  long i, avn, argn, flags;

  avalue = alloca(cif->nargs * sizeof(void *));
  flags = cif->flags;
  argn = 0;

  /* Copy the caller's structure return address to that the closure
     returns the data directly to the caller.  */
  if (flags == ALPHA_RET_IN_MEM)
    {
      rvalue = (void *) argp[0];
      argn = 1;
    }

  arg_types = cif->arg_types;

  /* Grab the addresses of the arguments from the stack frame.  */
  for (i = 0, avn = cif->nargs; i < avn; i++)
    {
      ffi_type *ty = arg_types[i];
      int type = ty->type;
      void *valp = &argp[argn];
      size_t size;

      switch (type)
	{
	case FFI_TYPE_INT:
	case FFI_TYPE_SINT8:
	case FFI_TYPE_UINT8:
	case FFI_TYPE_SINT16:
	case FFI_TYPE_UINT16:
	case FFI_TYPE_SINT32:
	case FFI_TYPE_UINT32:
	case FFI_TYPE_SINT64:
	case FFI_TYPE_UINT64:
	case FFI_TYPE_POINTER:
	  argn += 1;
	  break;

	case FFI_TYPE_VOID:
	case FFI_TYPE_STRUCT:
	  size = ty->size;
	  argn += FFI_ALIGN(size, FFI_SIZEOF_ARG) / FFI_SIZEOF_ARG;
	  break;

	case FFI_TYPE_FLOAT:
	  /* Floats coming from registers need conversion from double
	     back to float format.  */
	  if (argn < 6)
	    {
	      valp = &argp[argn - 6];
	      sts(valp, argp[argn - 6]);
	    }
	  argn += 1;
	  break;

	case FFI_TYPE_DOUBLE:
	  if (argn < 6)
	    valp = &argp[argn - 6];
	  argn += 1;
	  break;

	case FFI_TYPE_LONGDOUBLE:
	by_reference:
	  /* 128-bit long double is passed by reference.  */
	  valp = (void *)argp[argn];
	  argn += 1;
	  break;

	case FFI_TYPE_COMPLEX:
	  type = ty->elements[0]->type;
	  switch (type)
	    {
	    case FFI_TYPE_SINT64:
	    case FFI_TYPE_UINT64:
	      /* Passed as separate arguments, but they wind up sequential.  */
	      break;

	    case FFI_TYPE_INT:
	    case FFI_TYPE_SINT8:
	    case FFI_TYPE_UINT8:
	    case FFI_TYPE_SINT16:
	    case FFI_TYPE_UINT16:
	    case FFI_TYPE_SINT32:
	    case FFI_TYPE_UINT32:
	      /* Passed as separate arguments.  Disjoint, but there's room
		 enough in one slot to hold the pair.  */
	      size = ty->elements[0]->size;
	      memcpy(valp + size, valp + 8, size);
	      break;

	    case FFI_TYPE_FLOAT:
	      /* Passed as separate arguments.  Disjoint, and each piece
		 may need conversion back to float.  */
	      if (argn < 6)
		{
		  valp = &argp[argn - 6];
		  sts(valp, argp[argn - 6]);
		}
	      if (argn + 1 < 6)
		sts(valp + 4, argp[argn + 1 - 6]);
	      else
		*(UINT32 *)(valp + 4) = argp[argn + 1];
	      break;

	    case FFI_TYPE_DOUBLE:
	      /* Passed as separate arguments.  Only disjoint if one part
		 is in fp regs and the other is on the stack.  */
	      if (argn < 5)
		valp = &argp[argn - 6];
	      else if (argn == 5)
		{
		  valp = alloca(16);
		  ((UINT64 *)valp)[0] = argp[5 - 6];
		  ((UINT64 *)valp)[1] = argp[6];
		}
	      break;

	    case FFI_TYPE_LONGDOUBLE:
	      goto by_reference;

	    default:
	      abort();
	    }
	  argn += 2;
	  break;

	default:
	  abort ();
	}

      avalue[i] = valp;
    }

  /* Invoke the closure.  */
  fun (cif, rvalue, avalue, user_data);

  /* Tell ffi_closure_osf how to perform return type promotions.  */
  return (flags >> ALPHA_LD_SHIFT) & 0xff;
}