emit-rtl.c

这是完整的gcc源代码

{
  first_insn = first;
  last_insn = last;
}

/* Go through all the RTL insn bodies and copy any invalid shared structure.
   It does not work to do this twice, because the mark bits set here
   are not cleared afterwards.  */

static int unshare_copies = 0;	/* Count rtx's that were copied.  */

static rtx copy_rtx_if_shared ();

void
unshare_all_rtl (insn)
     register rtx insn;
{
  extern rtx stack_slot_list;

  for (; insn; insn = NEXT_INSN (insn))
    if (GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN
	|| GET_CODE (insn) == CALL_INSN)
      {
	PATTERN (insn) = copy_rtx_if_shared (PATTERN (insn));
	REG_NOTES (insn) = copy_rtx_if_shared (REG_NOTES (insn));
	LOG_LINKS (insn) = copy_rtx_if_shared (LOG_LINKS (insn));
      }

  /* Make sure the addresses of stack slots are not shared
     with anything in the insn chain.  That could happen if
     the stack slot is referenced only by its address.  */
  copy_rtx_if_shared (stack_slot_list);
}

/* Mark ORIG as in use, and return a copy of it if it was already in use.
   Recursively does the same for subexpressions.  */

static rtx
copy_rtx_if_shared (orig)
     rtx orig;
{
  register rtx x = orig;
  register int i;
  register enum rtx_code code;
  register char *format_ptr;
  int copied = 0;

  if (x == 0)
    return 0;

  code = GET_CODE (x);

  /* These types may be freely shared.  */

  switch (code)
    {
    case REG:
    case QUEUED:
    case CONST_INT:
    case CONST_DOUBLE:
    case SYMBOL_REF:
    case CODE_LABEL:
    case PC:
    case CC0:
      return x;

    case INSN:
    case JUMP_INSN:
    case CALL_INSN:
    case NOTE:
    case LABEL_REF:
    case BARRIER:
      /* The chain of insns is not being copied.  */
      return x;

    case MEM:
      /* A MEM is allowed to be shared if its address is constant
	 or is a constant plus one of the special registers.  */
      if (CONSTANT_ADDRESS_P (XEXP (x, 0)))
	return x;
      if (GET_CODE (XEXP (x, 0)) == PLUS
	  && (XEXP (XEXP (x, 0), 0) == frame_pointer_rtx
	      || XEXP (XEXP (x, 0), 0) == arg_pointer_rtx)
	  && CONSTANT_ADDRESS_P (XEXP (XEXP (x, 0), 1)))
	{
	  /* This MEM can appear in more than one place,
	     but its address better not be shared with anything else.  */
	  if (! x->used)
	    XEXP (x, 0) = copy_rtx_if_shared (XEXP (x, 0));
	  x->used = 1;
	  return x;
	}
      if (XEXP (x, 0) == frame_pointer_rtx
	  || XEXP (x, 0) == arg_pointer_rtx)
	return x;
    }

  /* This rtx may not be shared.  If it has already been seen,
     replace it with a copy of itself.  */

  if (x->used)
    {
      register rtx copy;

      unshare_copies++;

      copy = rtx_alloc (code);
      bcopy (x, copy, (sizeof (*copy) - sizeof (copy->fld)
		       + sizeof (copy->fld[0]) * GET_RTX_LENGTH (code)));
      x = copy;
      copied = 1;
    }
  x->used = 1;

  /* Now scan the subexpressions recursively.
     We can store any replaced subexpressions directly into X
     since we know X is not shared!  Any vectors in X
     must be copied if X was copied.  */

  format_ptr = GET_RTX_FORMAT (code);

  for (i = 0; i < GET_RTX_LENGTH (code); i++)
    {
      switch (*format_ptr++)
	{
	case 'e':
	  XEXP (x, i) = copy_rtx_if_shared (XEXP (x, i));
	  break;

	case 'E':
	  if (XVEC (x, i) != NULL)
	    {
	      register int j;

	      if (copied)
		XVEC (x, i) = gen_rtvec_v (XVECLEN (x, i), &XVECEXP (x, i, 0));
	      for (j = 0; j < XVECLEN (x, i); j++)
		XVECEXP (x, i, j)
		  = copy_rtx_if_shared (XVECEXP (x, i, j));
	    }
	  break;
	}
    }
  return x;
}

/* Copy X if necessary so that it won't be altered by changes in OTHER.
   Return X or the rtx for the pseudo reg the value of X was copied into.
   OTHER must be valid as a SET_DEST.  */

rtx
make_safe_from (x, other)
     rtx x, other;
{
  while (1)
    switch (GET_CODE (other))
      {
      case SUBREG:
	other = SUBREG_REG (other);
	break;
      case STRICT_LOW_PART:
      case SIGN_EXTEND:
      case ZERO_EXTEND:
	other = XEXP (other, 0);
	break;
      default:
	goto done;
      }
 done:
  if ((GET_CODE (other) == MEM
       && ! CONSTANT_P (x)
       && GET_CODE (x) != CONST_DOUBLE
       && GET_CODE (x) != REG
       && GET_CODE (x) != SUBREG)
      || (GET_CODE (other) == REG
	  && (REGNO (other) < FIRST_PSEUDO_REGISTER
	      || reg_mentioned_p (other, x))))
    {
      rtx temp = gen_reg_rtx (GET_MODE (x));
      emit_move_insn (temp, x);
      return temp;
    }
  return x;
}

/* Emission of insns (adding them to the doubly-linked list).  */

/* Return the first insn of the current sequence or current function.  */

rtx
get_insns ()
{
  return first_insn;
}

/* Return the last insn emitted in current sequence or current function.  */

rtx
get_last_insn ()
{
  return last_insn;
}

/* Specify a new insn as the last in the chain.  */

void
set_last_insn (insn)
     rtx insn;
{
  if (NEXT_INSN (insn) != 0)
    abort ();
  last_insn = insn;
}

/* Return a number larger than any instruction's uid in this function.  */

int
get_max_uid ()
{
  return cur_insn_uid;
}

rtx
next_insn (insn)
     rtx insn;
{
  if (insn) return NEXT_INSN (insn);
  return 0;
}

rtx
previous_insn (insn)
     rtx insn;
{
  if (insn) return PREV_INSN (insn);
  return 0;
}

/* Make and return an INSN rtx, initializing all its slots.
   Store PATTERN in the pattern slots.
   PAT_FORMALS is an idea that never really went anywhere.  */

static rtx
make_insn_raw (pattern, pat_formals)
     rtx pattern;
     rtvec pat_formals;
{
  register rtx insn;

  insn = rtx_alloc(INSN);
  INSN_UID(insn) = cur_insn_uid++;

  PATTERN (insn) = pattern;
  INSN_CODE (insn) = -1;
  LOG_LINKS(insn) = NULL;
  REG_NOTES(insn) = NULL;

  return insn;
}

/* Like `make_insn' but make a JUMP_INSN instead of an insn.  */

static rtx
make_jump_insn_raw (pattern, pat_formals)
     rtx pattern;
     rtvec pat_formals;
{
  register rtx insn;

  insn = rtx_alloc(JUMP_INSN);
  INSN_UID(insn) = cur_insn_uid++;

  PATTERN (insn) = pattern;
  INSN_CODE (insn) = -1;
  LOG_LINKS(insn) = NULL;
  REG_NOTES(insn) = NULL;
  JUMP_LABEL(insn) = NULL;

  return insn;
}

/* Add INSN to the end of the doubly-linked list.
   INSN may be an INSN, JUMP_INSN, CALL_INSN, CODE_LABEL, BARRIER or NOTE.  */

static void
add_insn (insn)
     register rtx insn;
{
  PREV_INSN (insn) = last_insn;
  NEXT_INSN (insn) = 0;

  if (NULL != last_insn)
    NEXT_INSN (last_insn) = insn;

  if (NULL == first_insn)
    first_insn = insn;

  last_insn = insn;
}

/* Add INSN, an rtx of code INSN, into the doubly-linked list
   after insn AFTER.  */

static void
add_insn_after (insn, after)
     rtx insn, after;
{
  NEXT_INSN (insn) = NEXT_INSN (after);
  PREV_INSN (insn) = after;

  if (NEXT_INSN (insn))
    PREV_INSN (NEXT_INSN (insn)) = insn;
  else if (last_insn == after)
    last_insn = insn;
  else
    {
      rtx stack = sequence_stack;
      /* Scan all pending sequences too.  */
      for (; stack; stack = XEXP (XEXP (stack, 1), 1))
	if (after == XEXP (XEXP (stack, 1), 0))
	  XEXP (XEXP (stack, 1), 0) = insn;
    }

  NEXT_INSN (after) = insn;
}

/* Delete all insns made since FROM.
   FROM becomes the new last instruction.  */

void
delete_insns_since (from)
     rtx from;
{
  if (from == 0)
    first_insn = 0;
  else
    NEXT_INSN (from) = 0;
  last_insn = from;
}

/* Move a consecutive bunch of insns to a different place in the chain.
   The insns to be moved are those between FROM and TO.
   They are moved to a new position after the insn AFTER.  */

void
reorder_insns (from, to, after)
     rtx from, to, after;
{
  /* Splice this bunch out of where it is now.  */
  if (PREV_INSN (from))
    NEXT_INSN (PREV_INSN (from)) = NEXT_INSN (to);
  if (NEXT_INSN (to))
    PREV_INSN (NEXT_INSN (to)) = PREV_INSN (from);
  if (last_insn == to)
    last_insn = PREV_INSN (from);
  if (first_insn == from)
    first_insn = NEXT_INSN (to);

  /* Make the new neighbors point to it and it to them.  */
  if (NEXT_INSN (after))
    {
      PREV_INSN (NEXT_INSN (after)) = to;
      NEXT_INSN (to) = NEXT_INSN (after);
    }
  PREV_INSN (from) = after;
  NEXT_INSN (after) = from;
  if (after == last_insn)
    last_insn = to;
}

/* Emit an insn of given code and pattern
   at a specified place within the doubly-linked list.  */

/* Make an instruction with body PATTERN
   and output it before the instruction BEFORE.  */

rtx
emit_insn_before (pattern, before)
     register rtx pattern, before;
{
  register rtx insn;

  if (GET_CODE (pattern) == SEQUENCE)
    {
      register int i;
      /* For an empty sequence, emit nothing.  */
      if (XVEC (pattern, 0))
	for (i = 0; i < XVECLEN (pattern, 0); i++)
	  add_insn_after (XVECEXP (pattern, 0, i), PREV_INSN (before));
      return PREV_INSN (before);
    }

  insn = make_insn_raw (pattern, 0);

  PREV_INSN (insn) = PREV_INSN (before);
  NEXT_INSN (insn) = before;

  if (PREV_INSN (insn))
    NEXT_INSN (PREV_INSN (insn)) = insn;
  else
    first_insn = insn;
  PREV_INSN (before) = insn;

  return insn;
}

/* Make an instruction with body PATTERN and code JUMP_INSN
   and output it before the instruction BEFORE.  */

rtx
emit_jump_insn_before (pattern, before)
     register rtx pattern, before;
{
  register rtx insn = make_jump_insn_raw (pattern, 0);

  PREV_INSN (insn) = PREV_INSN (before);
  NEXT_INSN (insn) = before;

  if (PREV_INSN (insn))
    NEXT_INSN (PREV_INSN (insn)) = insn;
  else
    first_insn = insn;
  PREV_INSN (before) = insn;

  return insn;
}

/* Make an instruction with body PATTERN and code CALL_INSN
   and output it before the instruction BEFORE.  */

rtx
emit_call_insn_before (pattern, before)
     register rtx pattern, before;
{
  rtx insn = emit_insn_before (pattern, before);
  PUT_CODE (insn, CALL_INSN);
  return insn;
}

/* Make an insn of code INSN with body PATTERN
   and output it after the insn AFTER.  */

rtx
emit_insn_after (pattern, after)
     register rtx pattern, after;
{
  if (GET_CODE (pattern) == SEQUENCE)
    {
      register int i;
      /* For an empty sequence, emit nothing.  */
      if (XVEC (pattern, 0))
	for (i = 0; i < XVECLEN (pattern, 0); i++)
	  {
	    add_insn_after (XVECEXP (pattern, 0, i), after);
	    after = NEXT_INSN (after);
	  }
      return after;
    }
  else
    {
      register rtx insn = make_insn_raw (pattern, 0);
      add_insn_after (insn, after);
      return insn;
    }
}

/* Make an insn of code JUMP_INSN with body PATTERN
   and output it after the insn AFTER.  */

rtx
emit_jump_insn_after (pattern, after)
     register rtx pattern, after;
{
  register rtx insn = make_jump_insn_raw (pattern, 0);

  add_insn_after (insn, after);
  return insn;
}

/* Make an insn of code BARRIER
   and output it after the insn AFTER.  */

rtx
emit_barrier_after (after)
     register rtx after;
{
  register rtx insn = rtx_alloc (BARRIER);

  INSN_UID (insn) = cur_insn_uid++;

  add_insn_after (insn, after);
  return insn;
}

/* Emit the label LABEL after the insn AFTER.  */

void
emit_label_after (label, after)
     rtx label, after;
{
  /* This can be called twice for the same label
     as a result of the confusion that follows a syntax error!
     So make it harmless.  */
  if (INSN_UID (label) == 0)
    {
      INSN_UID (label) = cur_insn_uid++;
      add_insn_after (label, after);
    }
}

/* Emit a note of subtype SUBTYPE after the insn AFTER.  */

void
emit_note_after (subtype, after)
     int subtype;
     rtx after;
{
  register rtx note = rtx_alloc (NOTE);
  INSN_UID (note) = cur_insn_uid++;
  XSTR (note, 3) = 0;
  XINT (note, 4) = subtype;
  add_insn_after (note, after);
}

/* Make an insn of code INSN with pattern PATTERN
   and add it to the end of the doubly-linked list.
   If PATTERN is a SEQUENCE, take the elements of it
   and emit an insn for each element.

   Returns the last insn emitted.  */

rtx
emit_insn (pattern)
     rtx pattern;
{
  rtx insn;

  if (GET_CODE (pattern) == SEQUENCE)
    {
      register int i;
      /* For an empty sequence, emit nothing.  */
      if (XVEC (pattern, 0))
	for (i = 0; i < XVECLEN (pattern, 0); i++)
	  add_insn (insn = XVECEXP (pattern, 0, i));
    }
  else
    {