ffi.c

gcc的组建

/* -----------------------------------------------------------------------
   ffi.c - 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 <stdlib.h>
#include <stdio.h>


extern void ffi_closure_SYSV(void);
extern void FFI_HIDDEN ffi_closure_LINUX64(void);

enum {
  /* The assembly depends on these exact flags.  */
  FLAG_RETURNS_SMST	= 1 << (31-31), /* Used for FFI_SYSV small structs.  */
  FLAG_RETURNS_NOTHING  = 1 << (31-30), /* These go in cr7 */
  FLAG_RETURNS_FP       = 1 << (31-29),
  FLAG_RETURNS_64BITS   = 1 << (31-28),
  FLAG_RETURNS_128BITS  = 1 << (31-27),

  FLAG_ARG_NEEDS_COPY   = 1 << (31- 7),
  FLAG_FP_ARGUMENTS     = 1 << (31- 6), /* cr1.eq; specified by ABI */
  FLAG_4_GPR_ARGUMENTS  = 1 << (31- 5),
  FLAG_RETVAL_REFERENCE = 1 << (31- 4)
};

/* About the SYSV ABI.  */
enum {
  NUM_GPR_ARG_REGISTERS = 8,
  NUM_FPR_ARG_REGISTERS = 8
};
enum { ASM_NEEDS_REGISTERS = 4 };

/* ffi_prep_args_SYSV is called by the assembly routine once stack space
   has been allocated for the function's arguments.

   The stack layout we want looks like this:

   |   Return address from ffi_call_SYSV 4bytes	|	higher addresses
   |--------------------------------------------|
   |   Previous backchain pointer	4	|       stack pointer here
   |--------------------------------------------|<+ <<<	on entry to
   |   Saved r28-r31			4*4	| |	ffi_call_SYSV
   |--------------------------------------------| |
   |   GPR registers r3-r10		8*4	| |	ffi_call_SYSV
   |--------------------------------------------| |
   |   FPR registers f1-f8 (optional)	8*8	| |
   |--------------------------------------------| |	stack	|
   |   Space for copied structures		| |	grows	|
   |--------------------------------------------| |	down    V
   |   Parameters that didn't fit in registers  | |
   |--------------------------------------------| |	lower addresses
   |   Space for callee's LR		4	| |
   |--------------------------------------------| |	stack pointer here
   |   Current backchain pointer	4	|-/	during
   |--------------------------------------------|   <<<	ffi_call_SYSV

*/

/*@-exportheader@*/
void ffi_prep_args_SYSV(extended_cif *ecif, unsigned *const stack)
/*@=exportheader@*/
{
  const unsigned bytes = ecif->cif->bytes;
  const unsigned flags = ecif->cif->flags;

  /* 'stacktop' points at the previous backchain pointer.  */
  unsigned *const stacktop = stack + (bytes / sizeof(unsigned));

  /* 'gpr_base' points at the space for gpr3, and grows upwards as
     we use GPR registers.  */
  unsigned *gpr_base = stacktop - ASM_NEEDS_REGISTERS - NUM_GPR_ARG_REGISTERS;
  int intarg_count = 0;

  /* 'fpr_base' points at the space for fpr1, and grows upwards as
     we use FPR registers.  */
  double *fpr_base = (double *)gpr_base - NUM_FPR_ARG_REGISTERS;
  int fparg_count = 0;

  /* 'copy_space' grows down as we put structures in it.  It should
     stay 16-byte aligned.  */
  char *copy_space = ((flags & FLAG_FP_ARGUMENTS)
		      ? (char *)fpr_base
		      : (char *)gpr_base);

  /* 'next_arg' grows up as we put parameters in it.  */
  unsigned *next_arg = stack + 2;

  int i;
  ffi_type **ptr;
  double double_tmp;
  void **p_argv;
  size_t struct_copy_size;
  unsigned gprvalue;

  /* Check that everything starts aligned properly.  */
  FFI_ASSERT(((unsigned)(char *)stack & 0xF) == 0);
  FFI_ASSERT(((unsigned)(char *)copy_space & 0xF) == 0);
  FFI_ASSERT(((unsigned)(char *)stacktop & 0xF) == 0);
  FFI_ASSERT((bytes & 0xF) == 0);
  FFI_ASSERT(copy_space >= (char *)next_arg);

  /* Deal with return values that are actually pass-by-reference.  */
  if (flags & FLAG_RETVAL_REFERENCE)
    {
      *gpr_base++ = (unsigned long)(char *)ecif->rvalue;
      intarg_count++;
    }

  /* Now for the arguments.  */
  p_argv = ecif->avalue;
  for (ptr = ecif->cif->arg_types, i = ecif->cif->nargs;
       i > 0;
       i--, ptr++, p_argv++)
    {
      switch ((*ptr)->type)
	{
	case FFI_TYPE_FLOAT:
	  double_tmp = *(float *)*p_argv;
	  if (fparg_count >= NUM_FPR_ARG_REGISTERS)
	    {
	      *(float *)next_arg = (float)double_tmp;
	      next_arg += 1;
	    }
	  else
	    *fpr_base++ = double_tmp;
	  fparg_count++;
	  FFI_ASSERT(flags & FLAG_FP_ARGUMENTS);
	  break;

	case FFI_TYPE_DOUBLE:
	  double_tmp = *(double *)*p_argv;

	  if (fparg_count >= NUM_FPR_ARG_REGISTERS)
	    {
	      if (intarg_count >= NUM_GPR_ARG_REGISTERS
		  && intarg_count % 2 != 0)
		{
		  intarg_count++;
		  next_arg++;
		}
	      *(double *)next_arg = double_tmp;
	      next_arg += 2;
	    }
	  else
	    *fpr_base++ = double_tmp;
	  fparg_count++;
	  FFI_ASSERT(flags & FLAG_FP_ARGUMENTS);
	  break;

	case FFI_TYPE_UINT64:
	case FFI_TYPE_SINT64:
	  if (intarg_count == NUM_GPR_ARG_REGISTERS-1)
	    intarg_count++;
	  if (intarg_count >= NUM_GPR_ARG_REGISTERS)
	    {
	      if (intarg_count%2 != 0)
		{
		  intarg_count++;
		  next_arg++;
		}
	      *(long long *)next_arg = *(long long *)*p_argv;
	      next_arg += 2;
	    }
	  else
	    {
	      /* whoops: abi states only certain register pairs
	       * can be used for passing long long int
	       * specifically (r3,r4), (r5,r6), (r7,r8),
	       * (r9,r10) and if next arg is long long but
	       * not correct starting register of pair then skip
	       * until the proper starting register
	       */
	      if (intarg_count%2 != 0)
		{
		  intarg_count ++;
		  gpr_base++;
		}
	      *(long long *)gpr_base = *(long long *)*p_argv;
	      gpr_base += 2;
	    }
	  intarg_count += 2;
	  break;

	case FFI_TYPE_STRUCT:
#if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
	case FFI_TYPE_LONGDOUBLE:
#endif
	  struct_copy_size = ((*ptr)->size + 15) & ~0xF;
	  copy_space -= struct_copy_size;
	  memcpy(copy_space, (char *)*p_argv, (*ptr)->size);

	  gprvalue = (unsigned long)copy_space;

	  FFI_ASSERT(copy_space > (char *)next_arg);
	  FFI_ASSERT(flags & FLAG_ARG_NEEDS_COPY);
	  goto putgpr;

	case FFI_TYPE_UINT8:
	  gprvalue = *(unsigned char *)*p_argv;
	  goto putgpr;
	case FFI_TYPE_SINT8:
	  gprvalue = *(signed char *)*p_argv;
	  goto putgpr;
	case FFI_TYPE_UINT16:
	  gprvalue = *(unsigned short *)*p_argv;
	  goto putgpr;
	case FFI_TYPE_SINT16:
	  gprvalue = *(signed short *)*p_argv;
	  goto putgpr;

	case FFI_TYPE_INT:
	case FFI_TYPE_UINT32:
	case FFI_TYPE_SINT32:
	case FFI_TYPE_POINTER:
	  gprvalue = *(unsigned *)*p_argv;
	putgpr:
	  if (intarg_count >= NUM_GPR_ARG_REGISTERS)
	    *next_arg++ = gprvalue;
	  else
	    *gpr_base++ = gprvalue;
	  intarg_count++;
	  break;
	}
    }

  /* Check that we didn't overrun the stack...  */
  FFI_ASSERT(copy_space >= (char *)next_arg);
  FFI_ASSERT(gpr_base <= stacktop - ASM_NEEDS_REGISTERS);
  FFI_ASSERT((unsigned *)fpr_base
	     <= stacktop - ASM_NEEDS_REGISTERS - NUM_GPR_ARG_REGISTERS);
  FFI_ASSERT(flags & FLAG_4_GPR_ARGUMENTS || intarg_count <= 4);
}

/* About the LINUX64 ABI.  */
enum {
  NUM_GPR_ARG_REGISTERS64 = 8,
  NUM_FPR_ARG_REGISTERS64 = 13
};
enum { ASM_NEEDS_REGISTERS64 = 4 };

/* ffi_prep_args64 is called by the assembly routine once stack space
   has been allocated for the function's arguments.

   The stack layout we want looks like this:

   |   Ret addr from ffi_call_LINUX64	8bytes	|	higher addresses
   |--------------------------------------------|
   |   CR save area			8bytes	|
   |--------------------------------------------|
   |   Previous backchain pointer	8	|	stack pointer here
   |--------------------------------------------|<+ <<<	on entry to
   |   Saved r28-r31			4*8	| |	ffi_call_LINUX64
   |--------------------------------------------| |
   |   GPR registers r3-r10		8*8	| |
   |--------------------------------------------| |
   |   FPR registers f1-f13 (optional)	13*8	| |
   |--------------------------------------------| |
   |   Parameter save area		        | |
   |--------------------------------------------| |
   |   TOC save area			8	| |
   |--------------------------------------------| |	stack	|
   |   Linker doubleword		8	| |	grows	|
   |--------------------------------------------| |	down	V
   |   Compiler doubleword		8	| |
   |--------------------------------------------| |	lower addresses
   |   Space for callee's LR		8	| |
   |--------------------------------------------| |
   |   CR save area			8	| |
   |--------------------------------------------| |	stack pointer here
   |   Current backchain pointer	8	|-/	during
   |--------------------------------------------|   <<<	ffi_call_LINUX64

*/

/*@-exportheader@*/
void FFI_HIDDEN ffi_prep_args64(extended_cif *ecif, unsigned long *const stack)
/*@=exportheader@*/
{
  const unsigned long bytes = ecif->cif->bytes;
  const unsigned long flags = ecif->cif->flags;

  /* 'stacktop' points at the previous backchain pointer.  */
  unsigned long *const stacktop = stack + (bytes / sizeof(unsigned long));

  /* 'next_arg' points at the space for gpr3, and grows upwards as
     we use GPR registers, then continues at rest.  */
  unsigned long *const gpr_base = stacktop - ASM_NEEDS_REGISTERS64
    - NUM_GPR_ARG_REGISTERS64;
  unsigned long *const gpr_end = gpr_base + NUM_GPR_ARG_REGISTERS64;
  unsigned long *const rest = stack + 6 + NUM_GPR_ARG_REGISTERS64;
  unsigned long *next_arg = gpr_base;

  /* 'fpr_base' points at the space for fpr3, and grows upwards as
     we use FPR registers.  */
  double *fpr_base = (double *)gpr_base - NUM_FPR_ARG_REGISTERS64;
  int fparg_count = 0;

  int i, words;
  ffi_type **ptr;
  double double_tmp;
  void **p_argv;
  unsigned long gprvalue;

  /* Check that everything starts aligned properly.  */
  FFI_ASSERT(((unsigned long)(char *)stack & 0xF) == 0);
  FFI_ASSERT(((unsigned long)(char *)stacktop & 0xF) == 0);
  FFI_ASSERT((bytes & 0xF) == 0);

  /* Deal with return values that are actually pass-by-reference.  */
  if (flags & FLAG_RETVAL_REFERENCE)
    *next_arg++ = (unsigned long)(char *)ecif->rvalue;

  /* Now for the arguments.  */
  p_argv = ecif->avalue;
  for (ptr = ecif->cif->arg_types, i = ecif->cif->nargs;
       i > 0;
       i--, ptr++, p_argv++)
    {
      switch ((*ptr)->type)
	{
	case FFI_TYPE_FLOAT:
	  double_tmp = *(float *)*p_argv;
	  *(float *)next_arg = (float)double_tmp;
	  if (++next_arg == gpr_end)
	    next_arg = rest;
	  if (fparg_count < NUM_FPR_ARG_REGISTERS64)
	    *fpr_base++ = double_tmp;
	  fparg_count++;
	  FFI_ASSERT(flags & FLAG_FP_ARGUMENTS);
	  break;

	case FFI_TYPE_DOUBLE:
	  double_tmp = *(double *)*p_argv;
	  *(double *)next_arg = double_tmp;
	  if (++next_arg == gpr_end)
	    next_arg = rest;
	  if (fparg_count < NUM_FPR_ARG_REGISTERS64)
	    *fpr_base++ = double_tmp;
	  fparg_count++;
	  FFI_ASSERT(flags & FLAG_FP_ARGUMENTS);
	  break;

#if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
	case FFI_TYPE_LONGDOUBLE:
	  double_tmp = ((double *) *p_argv)[0];
	  *(double *) next_arg = double_tmp;
	  if (++next_arg == gpr_end)
	    next_arg = rest;
	  if (fparg_count < NUM_FPR_ARG_REGISTERS64)
	    *fpr_base++ = double_tmp;
	  fparg_count++;
	  double_tmp = ((double *) *p_argv)[1];
	  *(double *) next_arg = double_tmp;
	  if (++next_arg == gpr_end)
	    next_arg = rest;
	  if (fparg_count < NUM_FPR_ARG_REGISTERS64)
	    *fpr_base++ = double_tmp;
	  fparg_count++;
	  FFI_ASSERT(flags & FLAG_FP_ARGUMENTS);
	  break;
#endif

	case FFI_TYPE_STRUCT:
	  words = ((*ptr)->size + 7) / 8;
	  if (next_arg >= gpr_base && next_arg + words > gpr_end)
	    {