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/*

    Copyright (c) 1993 Open Software Foundation, Inc.

    All Rights Reserved

    Permission to use, copy, modify, and distribute this software

    and its documentation for any purpose and without fee is hereby

    granted, provided that the above copyright notice appears in all

    copies and that both the copyright notice and this permission

    notice appear in supporting documentation.

    OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING

    ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A

    PARTICULAR PURPOSE.

    IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR

    CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM

    LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,

    NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION

    WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

*/

/*

    		 Crown Copyright (c) 1997

    This TenDRA(r) Computer Program is subject to Copyright

    owned by the United Kingdom Secretary of State for Defence

    acting through the Defence Evaluation and Research Agency

    (DERA).  It is made available to Recipients with a

    royalty-free licence for its use, reproduction, transfer

    to other parties and amendment for any purpose not excluding

    product development provided that any such use et cetera

    shall be deemed to be acceptance of the following conditions:-

        (1) Its Recipients shall ensure that this Notice is

        reproduced upon any copies or amended versions of it;

        (2) Any amended version of it shall be clearly marked to

        show both the nature of and the organisation responsible

        for the relevant amendment or amendments;

        (3) Its onward transfer from a recipient to another

        party shall be deemed to be that party's acceptance of

        these conditions;

        (4) DERA gives no warranty or assurance as to its

        quality or suitability for any purpose and DERA accepts

        no liability whatsoever in relation to any use to which

        it may be put.

*/

/**********************************************************************

$Author: release $

$Date: 1998/02/04 15:48:46 $

$Revision: 1.2 $

$Log: frames.c,v $

 * Revision 1.2  1998/02/04  15:48:46  release

 * Added OSF copyright message.

 *

 * Revision 1.1.1.1  1998/01/17  15:55:56  release

 * First version to be checked into rolling release.

 *

 * Revision 1.3  1996/10/14  17:31:47  pwe

 * include called callees in env_size

 *

 * Revision 1.2  1996/10/04  16:00:52  pwe

 * add banners and mod for PWE ownership

 *

**********************************************************************/

#include "config.h"

#include "memtdf.h"

#include "codegen.h"

#include "installglob.h"

#include "basicread.h"

#include "main_reads.h"

#include "optimise.h"

#include "exp.h"

#include "flpt.h"	

#include "externs.h"	    

#include "myassert.h"

#include "tempdecs.h"

#include "weights.h"

#include "procrecs.h"

#include "regalloc.h"

#include "makecode.h"

#include "eval.h"

#include "flags.h"

#include "needscan.h"

#include "machine.h"

#include "diagout.h"

#include "xalloc.h"

#include "comment.h"

#include "translat.h"

#include "readglob.h"

#include "stack.h"

#include "frames.h"

long frame_offset PROTO_N ((id)) PROTO_T (exp id)

{

  exp init_exp = son(id);

  exp p;

  procrec *pr;

  long n = no (id);

  long off = n>>6;

  ASSERT(name(id) == ident_tag);

  for (p = father(id); !IS_A_PROC(p); p = father(p));

  pr = & procrecs[no(p)];

  if (isparam(id))

  {

    if( name(init_exp)==formal_callee_tag)

    {

      /* Callee parameter accessed through R_FP */

      return (no(init_exp)>>3) + EXTRA_CALLEE_BYTES;

    }

    else

    {

      /* Caller parameter accessed through R_TP */

      return (no(init_exp)>>3) + STACK_ARG_AREA;

    }

  }

  else if (name(init_exp)==caller_name_tag)

  {

    fail("Taking env_offset of an identified caller within a postlude");

    return 0;

  }

  else

  {

    /* Local */

    return ( off + (pr->locals_offset>>3) - (pr->frame_size>>3) );

  }

}

void set_up_frame_pointer PROTO_N ((pr,e)) PROTO_T (procrec * pr X exp e )

{

  long pprops = pr->needsproc.propsneeds;

  /* Initialize a few of the fields */

  pr->alloca_proc = proc_has_alloca(e);

  pr->leaf_proc = ( ( pprops & anyproccall ) == 0);

  pr->has_fp = 0;

  pr->has_saved_sp = 0;

  pr->save_all_sregs = 0;

  pr->has_vcallees = 0;

  pr->has_no_vcallers = 0;

  pr->has_tp = 0;

  /* 

   * This choosing of what is needed within the proc is very important

   * For a procedure which is not a leaf proc and has had someone loading

   * the value of a label, and someone has grabbed the current_env

   * It means, that they could potentially long jump into this proc.

   * In this case we must save all the s-regs, and also we must insist

   * on a frame pointer.

   * The reason for this, is that there is no way of telling when coding

   * up the long jump whether the proc it is long jumping into has a

   * frame pointer or not.

   * So to make a convention we say that it must have a frame pointer,

   * since this is the only way we can code up the long jump.(by loading fp )

   *

   * In the event of us having a procedure which could be long jumped

   * back to, and the proc has calls to alloca, then the stack pointer can

   * not be restored from the frame pointer, by simply subtracting the 

   * p_frame_size, so it is necessary to save the last value of the stack pointer

   * at a designated place on the stack relative to the frame pointer.

   */

  if( !(pr->leaf_proc) && proc_has_lv(e) && proc_uses_crt_env(e) )

  {

    /* This means someone could call long jump back to this proc */

    pr->save_all_sregs = 1;

    pr->has_fp = 1;

  }

  if ( pr->alloca_proc )

  {

    /* alloca procedures require a frame pointer */

    pr->has_fp = 1;

  }

  if ( pr->alloca_proc && pr->save_all_sregs )

  {

    /* alloca proc which could be long jumped to */

    pr->has_saved_sp = 1;

  }

  if (name(e)==general_proc_tag)

  {

    /* All general_proc_tag's have a frame pointer */

    pr->has_tp = 1;/* +++ is this only really needed for vcallees */

    pr->has_fp = 1;

    pr->has_vcallees = proc_has_vcallees(e);

    pr->has_no_vcallers = !proc_has_vcallers(e);

    /* If has_no_vcallers==1 => Not a varargs

       however has_no_vcallers==0 does not imply varargs it tells us nothing*/

  }

  if (gen_call!=0)

  {

    /* It could be a normal proc with a tail call */

    pr->has_fp = 1;

  }

  pr->no_of_returns = no_of_returns;  

  pr->callee_size = callee_size;

  if (max_callees < 0)

    pr->max_callee_bytes = 0;

  else

    pr->max_callee_bytes = ALIGNNEXT ((max_callees >> 3) + EXTRA_CALLEE_BYTES, 8);

  return;

}

void set_up_frame_info PROTO_N ((pr,e)) PROTO_T (procrec * pr X exp e )

{

  int r;

  long maxargs;

  /*

   * Initialize more fields

   */

  maxargs = pr->needsproc.maxargs;

  pr->locals_space = pr->spacereqproc.stack;      

  if (do_profile)

  {

    pr->leaf_proc = 0;

  }

  if (pr->leaf_proc)

  {

    COMMENT("leaf_proc");

    ASSERT(maxargs==0);

  }

  else

  {

    ASSERT(maxargs >=0);

    if (maxargs < STACK_MIN_MAXARGS*8)

    {

      maxargs = STACK_MIN_MAXARGS*8;	/* at least reg param dump for calls */

    }

  }

  /* put on 64 bit boundaries */

  maxargs = ALIGNNEXT(maxargs, 64);

  pr->locals_space = ALIGNNEXT(pr->locals_space, 64);

  /* find lowest s-reg used for i_stm and i_lm */

  pr->sreg_first_save = R_NO_REG;

  for (r = R_FIRST; r <= R_LAST; r++)

  {

    if ((pr->spacereqproc.fixdump & RMASK(r)) != 0)

    {

      pr->sreg_first_save = r;

      break;

    }

  }

  COMMENT2("gpr use mask = %#x, lowest = %d", pr->spacereqproc.fixdump, pr->sreg_first_save);

  ASSERT(pr->sreg_first_save==R_NO_REG || IS_SREG(pr->sreg_first_save));

  /* find lowest float s-reg used */

  pr->sfreg_first_save = FR_NO_REG;

  for (r = FR_FIRST; r <= FR_LAST; r++)

  {

    if ((pr->spacereqproc.fltdump & RMASK(r)) != 0)

    {

      pr->sfreg_first_save = r;

      break;

    }

  }

  COMMENT2("fpr use mask = %#x, lowest = %d", pr->spacereqproc.fltdump, pr->sfreg_first_save);

  ASSERT(pr->sfreg_first_save==FR_NO_REG || IS_FLT_SREG(pr->sfreg_first_save));

  if (pr->leaf_proc)

  {

    pr->locals_offset = 0;

  }

  else

  {

    pr->locals_offset = STACK_LINK_AREA_SIZE*8 + maxargs;

  }

  pr->frame_size= pr->locals_offset + pr->locals_space;

  /* GRAB TWO WORDS FOR THE SAVED SP */

  if (pr->has_saved_sp)

  {

    pr->frame_size += 64;

    /* Two extra words */

  }

  /* grab space for fixed s-reg dump area */

  if (pr->sreg_first_save != R_NO_REG)

  {

    pr->frame_size += ALIGNNEXT((R_LAST-pr->sreg_first_save+1)*32, 64);

  }

  /* grab space for float s-reg dump area */

  if (pr->sfreg_first_save != FR_NO_REG)

  {

    pr->frame_size += (FR_LAST-pr->sfreg_first_save+1)*64;

  }

  pr->params_offset = pr->frame_size + STACK_ARG_AREA*8;

  pr->maxargs=maxargs;

  return;

}