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code.c

/*    $OpenBSD: code.c,v 1.2 2007/11/22 15:06:43 stefan Exp $     */

/*
 * Copyright (c) 2007 Michael Shalayeff
 * Copyright (c) 2003 Anders Magnusson (ragge@ludd.luth.se).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


# include "pass1.h"

NODE *funarg(NODE *, int *);
int argreg(TWORD, int *);

static const char *const loctbl[] = { "text", "data", "section .rodata" };

/*
 * Define everything needed to print out some data (or text).
 * This means segment, alignment, visibility, etc.
 */
void
defloc(struct symtab *sp)
{
      extern char *nextsect;
      static int lastloc = -1;
      TWORD t;
      char *n;
      int s;

      if (sp == NULL) {
            lastloc = -1;
            return;
      }
      t = sp->stype;
      s = ISFTN(t) ? PROG : ISCON(cqual(t, sp->squal)) ? RDATA : DATA;
      if (nextsect) {
            printf("\t.section %s\n", nextsect);
            nextsect = NULL;
            s = -1;
      } else if (s != lastloc)
            printf("\t.%s\n", loctbl[s]);
      lastloc = s;
      while (ISARY(t))
            t = DECREF(t);
      s = ISFTN(t) ? ALINT : talign(t, sp->ssue);
      if (s > ALCHAR)
            printf("\t.align\t%d\n", s / ALCHAR);
      n = sp->soname ? sp->soname : sp->sname;
      if (sp->sclass == EXTDEF)
            printf("\t.export %s, %s\n", n,
                ISFTN(t)? "code" : "data");
      if (sp->slevel == 0)
            printf("\t.type\t%s, @%s\n\t.label %s\n",
                n, ISFTN(t)? "function" : "object", n);
      else
            printf("\t.type\t" LABFMT ", @%s\n\t.label\t" LABFMT "\n", 
                sp->soffset, ISFTN(t)? "function" : "object", sp->soffset);
}

/*
 * code for the end of a function
 * deals with struct return here
 */
void
efcode()
{
      NODE *p, *q;
      int sz;

      if (cftnsp->stype != STRTY+FTN && cftnsp->stype != UNIONTY+FTN)
            return;
      /* address of return struct is in %ret0 */
      /* create a call to memcpy() */
      /* will get the result in %ret0 */
      p = block(REG, NIL, NIL, CHAR+PTR, 0, 0);
      p->n_rval = RET0;
      q = block(OREG, NIL, NIL, CHAR+PTR, 0, 0);
      q->n_rval = FP;
      q->n_lval = 8; /* return buffer offset */
      p = block(CM, q, p, INT, 0, 0);
      sz = (tsize(STRTY, cftnsp->sdf, cftnsp->ssue)+SZCHAR-1)/SZCHAR;
      p = block(CM, p, bcon(sz), INT, 0, 0);
      p->n_right->n_name = "";
      p = block(CALL, bcon(0), p, CHAR+PTR, 0, 0);
      p->n_left->n_name = "memcpy";
      p = clocal(p);
      send_passt(IP_NODE, p);
}

int
argreg(TWORD t, int *n)
{
      switch (t) {
      case FLOAT:
            return FR7L - 2 * (*n)++;
      case DOUBLE:
      case LDOUBLE:
            *n += 2;
            return FR6 - *n - 2;
      case LONGLONG:
      case ULONGLONG:
            *n += 2;
            return AD1 - (*n - 2) / 2;
      default:
            return ARG0 - (*n)++;
      }
}

/*
 * code for the beginning of a function; 'a' is an array of
 * indices in symtab for the arguments; n is the number
 */
void
bfcode(struct symtab **a, int cnt)
{
      struct symtab *sp;
      NODE *p, *q;
      int i, n, sz;

      if (cftnsp->stype == STRTY+FTN || cftnsp->stype == UNIONTY+FTN) {
            /* Function returns struct, adjust arg offset */
            for (i = 0; i < n; i++)
                  a[i]->soffset += SZPOINT(LONG);
      }

      /* recalculate the arg offset and create TEMP moves */
      for (n = 0, i = 0; i < cnt; i++) {
            sp = a[i];

            sz = szty(sp->stype);
            if (n % sz)
                  n++;  /* XXX LDOUBLE */

            if (n < 4) {
                  p = tempnode(0, sp->stype, sp->sdf, sp->ssue);
                  /* TODO p->n_left->n_lval = -(32 + n * 4); */
                  q = block(REG, NIL, NIL, sp->stype, sp->sdf, sp->ssue);
                  q->n_rval = argreg(sp->stype, &n);
                  p = buildtree(ASSIGN, p, q);
                  sp->soffset = regno(p->n_left);
                  sp->sflags |= STNODE;
                  ecomp(p);
            } else {
                  sp->soffset += SZINT * n;
                  if (xtemps) {
                        /* put stack args in temps if optimizing */
                        p = tempnode(0, sp->stype, sp->sdf, sp->ssue);
                        p = buildtree(ASSIGN, p, buildtree(NAME, 0, 0));
                        sp->soffset = regno(p->n_left);
                        sp->sflags |= STNODE;
                        ecomp(p);
                  }
            }
      }
}


/*
 * by now, the automatics and register variables are allocated
 */
void
bccode()
{
      SETOFF(autooff, SZINT);
}

/* called just before final exit */
/* flag is 1 if errors, 0 if none */
void
ejobcode(int errors)
{
      if (errors)
            return;

      printf("\t.end\n");
}

void
bjobcode(void)
{
      printf("\t.level\t1.1\n"
          "\t.import $global$, data\n"
          "\t.import $$dyncall, millicode\n");
}

/*
 * return the alignment of field of type t
 */
int
fldal(unsigned int t)
{
      uerror("illegal field type");
      return(ALINT);
}

/* fix up type of field p */
void
fldty(struct symtab *p)
{
}

/*
 * XXX - fix genswitch.
 */
int
mygenswitch(int num, TWORD type, struct swents **p, int n)
{
      return 0;
}

NODE *
funarg(NODE *p, int *n)
{
      NODE *r;
      int sz;

      if (p->n_op == CM) {
            p->n_left = funarg(p->n_left, n);
            p->n_right = funarg(p->n_right, n);
            return p;
      }

      sz = szty(p->n_type);
      if (*n % sz)
            (*n)++;     /* XXX LDOUBLE */

      if (*n >= 4) {
            *n += sz;
            r = block(OREG, NIL, NIL, p->n_type|PTR, 0, 0);
            r->n_rval = SP;
            r->n_lval = -(32 + *n * 4);
      } else {
            r = block(REG, NIL, NIL, p->n_type, 0, 0);
            r->n_lval = 0;
            r->n_rval = argreg(p->n_type, n);
      }
      p = block(ASSIGN, r, p, p->n_type, 0, 0);
      clocal(p);

      return p;
}

/*
 * Called with a function call with arguments as argument.
 * This is done early in buildtree() and only done once.
 */
NODE *
funcode(NODE *p)
{
      int n = 0;

      p->n_right = funarg(p->n_right, &n);
      return p;
}

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