emit-rtl.c

这是完整的gcc源代码

      insn = make_insn_raw (pattern, NULL);
      add_insn (insn);
    }
  return insn;
}

/* Emit the insns in a chain starting with INSN.  */

rtx
emit_insns (insn)
     rtx insn;
{
  while (insn)
    {
      rtx next = NEXT_INSN (insn);
      add_insn (insn);
      insn = next;
    }
}

/* Make an insn of code JUMP_INSN with pattern PATTERN
   and add it to the end of the doubly-linked list.  */

rtx
emit_jump_insn (pattern)
     rtx pattern;
{
  if (GET_CODE (pattern) == SEQUENCE)
    return emit_insn (pattern);
  else
    {
      register rtx insn = make_jump_insn_raw (pattern, NULL);
      add_insn (insn);
      return insn;
    }
}

/* Make an insn of code CALL_INSN with pattern PATTERN
   and add it to the end of the doubly-linked list.  */

rtx
emit_call_insn (pattern)
     rtx pattern;
{
  if (GET_CODE (pattern) == SEQUENCE)
    return emit_insn (pattern);
  else
    {
      register rtx insn = make_insn_raw (pattern, NULL);
      add_insn (insn);
      PUT_CODE (insn, CALL_INSN);
      return insn;
    }
}

/* Add the label LABEL to the end of the doubly-linked list.  */

rtx
emit_label (label)
     rtx label;
{
  /* 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 (label);
    }
  return label;
}

/* Make an insn of code BARRIER
   and add it to the end of the doubly-linked list.  */

rtx
emit_barrier ()
{
  register rtx barrier = rtx_alloc (BARRIER);
  INSN_UID (barrier) = cur_insn_uid++;
  add_insn (barrier);
  return barrier;
}

/* Make an insn of code NOTE
   with data-fields specified by FILE and LINE
   and add it to the end of the doubly-linked list,
   but only if line-numbers are desired for debugging info.  */

rtx
emit_line_note (file, line)
     char *file;
     int line;
{
  emit_filename = file;
  emit_lineno = line;

#if 0
  if (no_line_numbers)
    return 0;
#endif

  return emit_note (file, line);
}

/* Make an insn of code NOTE
   with data-fields specified by FILE and LINE
   and add it to the end of the doubly-linked list.
   If it is a line-number NOTE, omit it if it matches the previous one.  */

rtx
emit_note (file, line)
     char *file;
     int line;
{
  register rtx note;

  if (line > 0)
    {
      if (file && last_filename && !strcmp (file, last_filename)
	  && line == last_linenum)
	return 0;
      last_filename = file;
      last_linenum = line;
    }

  if (no_line_numbers && line > 0)
    {
      cur_insn_uid++;
      return 0;
    }

  note = rtx_alloc (NOTE);
  INSN_UID (note) = cur_insn_uid++;
  XSTR (note, 3) = file;
  XINT (note, 4) = line;
  add_insn (note);
  return note;
}

/* Emit a NOTE, and don't omit it even if LINE it the previous note.  */

rtx
emit_line_note_force (file, line)
     char *file;
     int line;
{
  last_linenum = -1;
  return emit_line_note (file, line);
}

/* Cause next statement to emit a line note even if the line number
   has not changed.  This is used at the beginning of a function.  */

void
force_next_line_note ()
{
  last_linenum = -1;
}

/* Return an indication of which type of insn should have X as a body.
   The value is CODE_LABEL, INSN, CALL_INSN or JUMP_INSN.  */

enum rtx_code
classify_insn (x)
     rtx x;
{
  if (GET_CODE (x) == CODE_LABEL)
    return CODE_LABEL;
  if (GET_CODE (x) == CALL)
    return CALL_INSN;
  if (GET_CODE (x) == RETURN)
    return JUMP_INSN;
  if (GET_CODE (x) == SET)
    {
      if (SET_DEST (x) == pc_rtx)
	return JUMP_INSN;
      else if (GET_CODE (SET_SRC (x)) == CALL)
	return CALL_INSN;
      else
	return INSN;
    }
  if (GET_CODE (x) == PARALLEL)
    {
      register int j;
      for (j = XVECLEN (x, 0) - 1; j >= 0; j--)
	if (GET_CODE (XVECEXP (x, 0, j)) == CALL)
	  return CALL_INSN;
	else if (GET_CODE (XVECEXP (x, 0, j)) == SET
		 && SET_DEST (XVECEXP (x, 0, j)) == pc_rtx)
	  return JUMP_INSN;
	else if (GET_CODE (XVECEXP (x, 0, j)) == SET
		 && GET_CODE (SET_SRC (XVECEXP (x, 0, j))) == CALL)
	  return CALL_INSN;
    }
  return INSN;
}

/* Emit the rtl pattern X as an appropriate kind of insn.
   If X is a label, it is simply added into the insn chain.  */

void
emit (x)
     rtx x;
{
  enum rtx_code code = classify_insn (x);

  if (code == CODE_LABEL)
    emit_label (x);
  else if (code == INSN)
    emit_insn (x);
  else if (code == JUMP_INSN)
    {
      register rtx insn = emit_jump_insn (x);
      if (simplejump_p (insn) || GET_CODE (x) == RETURN)
	emit_barrier ();
    }
  else if (code == CALL_INSN)
    emit_call_insn (x);
}

/* Begin emitting insns to a sequence which can be packaged in an RTL_EXPR.
   Return an rtx containing data on any sequence already in progress.  */

rtx
start_sequence ()
{
  sequence_stack
    = gen_rtx (INSN_LIST, VOIDmode,
	       first_insn, gen_rtx (INSN_LIST, VOIDmode,
				    last_insn, sequence_stack));
  first_insn = 0;
  last_insn = 0;
  return sequence_stack;
}

/* Set up the insn chain starting with FIRST
   as the current sequence, saving the previously current one.  */

void
push_to_sequence (first)
     rtx first;
{
  rtx last;
  for (last = first; last && NEXT_INSN (last); last = NEXT_INSN (last));
  sequence_stack
    = gen_rtx (INSN_LIST, VOIDmode,
	       first_insn, gen_rtx (INSN_LIST, VOIDmode,
				    last_insn, sequence_stack));
  first_insn = first;
  last_insn = last;
}

/* After emitting to a sequence, restore previous saved state.
   The argument SAVED is no longer used.

   To get the contents of the sequence just made,
   you must call `gen_sequence' *before* calling here.  */

void
end_sequence (saved)
     rtx saved;
{
  first_insn = XEXP (sequence_stack, 0);
  last_insn = XEXP (XEXP (sequence_stack, 1), 0);
  sequence_stack = XEXP (XEXP (sequence_stack, 1), 1);
}

/* Generate a SEQUENCE rtx containing the insns already emitted
   to the current sequence.

   This is how the gen_... function from a DEFINE_EXPAND
   constructs the SEQUENCE that it returns.  */

rtx
gen_sequence ()
{
  rtx tem;
  rtvec newvec;
  int i;
  int len;

  /* Count the insns in the chain.  */
  len = 0;
  for (tem = first_insn; tem; tem = NEXT_INSN (tem))
    len++;

  /* For an empty sequence... */
  if (len == 0)
    return gen_rtx (SEQUENCE, VOIDmode, NULL);

  /* If only one insn, return its pattern rather than a SEQUENCE.  */
  if (len == 1
      && (GET_CODE (first_insn) == INSN
	  || GET_CODE (first_insn) == JUMP_INSN
	  || GET_CODE (first_insn) == CALL_INSN))
    return PATTERN (first_insn);

  /* Put them in a vector.  */
  newvec = rtvec_alloc (len);
  i = 0;
  for (tem = first_insn; tem; tem = NEXT_INSN (tem), i++)
    newvec->elem[i].rtx = tem;

  /* Make a SEQUENCE from this vector.  */
  return gen_rtx (SEQUENCE, VOIDmode, newvec);
}

/* Set up regno_reg_rtx, reg_rtx_no and regno_pointer_flag
   according to the chain of insns starting with FIRST.

   Also set cur_insn_uid to exceed the largest uid in that chain.

   This is used when an inline function's rtl is saved
   and passed to rest_of_compilation later.  */

static void restore_reg_data_1 ();

void
restore_reg_data (first)
     rtx first;
{
  register rtx insn;
  int i;
  register int max_uid = 0;

  for (insn = first; insn; insn = NEXT_INSN (insn))
    {
      if (INSN_UID (insn) >= max_uid)
	max_uid = INSN_UID (insn);

      switch (GET_CODE (insn))
	{
	case NOTE:
	case CODE_LABEL:
	case BARRIER:
	  break;

	case JUMP_INSN:
	case CALL_INSN:
	case INSN:
	  restore_reg_data_1 (PATTERN (insn));
	  break;
	}
    }

  /* Don't duplicate the uids already in use.  */
  cur_insn_uid = max_uid + 1;

  /* If any regs are missing, make them up.  */
  for (i = FIRST_PSEUDO_REGISTER; i < reg_rtx_no; i++)
    if (regno_reg_rtx[i] == 0)
      regno_reg_rtx[i] = gen_rtx (REG, SImode, i);
}

static void
restore_reg_data_1 (orig)
     rtx orig;
{
  register rtx x = orig;
  register int i;
  register enum rtx_code code;
  register char *format_ptr;

  code = GET_CODE (x);

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

    case REG:
      if (REGNO (x) >= FIRST_PSEUDO_REGISTER)
	{
	  /* Make sure regno_pointer_flag and regno_reg_rtx are large
	     enough to have an element for this pseudo reg number.  */
	  if (REGNO (x) >= reg_rtx_no)
	    {
	      reg_rtx_no = REGNO (x);

	      if (reg_rtx_no >= regno_pointer_flag_length)
		{
		  int newlen = max (regno_pointer_flag_length * 2,
				    reg_rtx_no + 30);
		  rtx *new1;
		  char *new = (char *) oballoc (newlen);
		  bzero (new, newlen);
		  bcopy (regno_pointer_flag, new, regno_pointer_flag_length);

		  new1 = (rtx *) oballoc (newlen * sizeof (rtx));
		  bzero (new1, newlen * sizeof (rtx));
		  bcopy (regno_reg_rtx, new1, regno_pointer_flag_length * sizeof (rtx));

		  regno_pointer_flag = new;
		  regno_reg_rtx = new1;
		  regno_pointer_flag_length = newlen;
		}
	      reg_rtx_no ++;
	    }
	  regno_reg_rtx[REGNO (x)] = x;
	}
      return;

    case MEM:
      if (GET_CODE (XEXP (x, 0)) == REG)
	mark_reg_pointer (XEXP (x, 0));
      restore_reg_data_1 (XEXP (x, 0));
      return;
    }

  /* Now scan the subexpressions recursively.  */

  format_ptr = GET_RTX_FORMAT (code);

  for (i = 0; i < GET_RTX_LENGTH (code); i++)
    {
      switch (*format_ptr++)
	{
	case 'e':
	  restore_reg_data_1 (XEXP (x, i));
	  break;

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

	      for (j = 0; j < XVECLEN (x, i); j++)
		restore_reg_data_1 (XVECEXP (x, i, j));
	    }
	  break;
	}
    }
}

/* Initialize data structures and variables in this file
   before generating rtl for each function.
   WRITE_SYMBOLS is nonzero if any kind of debugging info
   is to be generated.  */

void
init_emit (write_symbols)
     int write_symbols;
{
  first_insn = NULL;
  last_insn = NULL;
  sequence_stack = NULL;
  cur_insn_uid = 1;
  reg_rtx_no = FIRST_PSEUDO_REGISTER;
  last_linenum = 0;
  last_filename = 0;
  first_label_num = label_num;

  no_line_numbers = ! write_symbols;
  
  /* Init the tables that describe all the pseudo regs.  */

  regno_pointer_flag_length = FIRST_PSEUDO_REGISTER + 100;

  regno_pointer_flag 
    = (char *) oballoc (regno_pointer_flag_length);
  bzero (regno_pointer_flag, regno_pointer_flag_length);

  regno_reg_rtx 
    = (rtx *) oballoc (regno_pointer_flag_length * sizeof (rtx));
  bzero (regno_reg_rtx, regno_pointer_flag_length * sizeof (rtx));
}

/* Create some permanent unique rtl objects shared between all functions.  */

void
init_emit_once ()
{
  /* Create the unique rtx's for certain rtx codes and operand values.  */

  pc_rtx = gen_rtx (PC, VOIDmode);
  cc0_rtx = gen_rtx (CC0, VOIDmode);

  /* Don't use gen_rtx here since gen_rtx in this case
     tries to use these variables.  */
  const0_rtx = rtx_alloc (CONST_INT);
  INTVAL (const0_rtx) = 0;
  const1_rtx = rtx_alloc (CONST_INT);
  INTVAL (const1_rtx) = 1;

  fconst0_rtx = rtx_alloc (CONST_DOUBLE);
  dconst0_rtx = rtx_alloc (CONST_DOUBLE);
  {
    union real_extract u;
#ifdef REAL_IS_NOT_DOUBLE
    bzero (&u, sizeof u);
    u.d = REAL_VALUE_ATOF ("0");
#else
    u.d = 0;
#endif

    bcopy (&u, &CONST_DOUBLE_LOW (fconst0_rtx), sizeof u);
    CONST_DOUBLE_MEM (fconst0_rtx) = cc0_rtx;
    PUT_MODE (fconst0_rtx, SFmode);

    bcopy (&u, &CONST_DOUBLE_LOW (dconst0_rtx), sizeof u);
    CONST_DOUBLE_MEM (dconst0_rtx) = cc0_rtx;
    PUT_MODE (dconst0_rtx, DFmode);
  }

  stack_pointer_rtx = gen_rtx (REG, Pmode, STACK_POINTER_REGNUM);
  frame_pointer_rtx = gen_rtx (REG, Pmode, FRAME_POINTER_REGNUM);
#ifdef STRUCT_VALUE
  struct_value_rtx = STRUCT_VALUE;
#else
  struct_value_rtx = gen_rtx (REG, Pmode, STRUCT_VALUE_REGNUM);
#endif

#ifdef STRUCT_VALUE_INCOMING
  struct_value_incoming_rtx = STRUCT_VALUE_INCOMING;
#else
#ifdef STRUCT_VALUE_INCOMING_REGNUM
  struct_value_incoming_rtx
    = gen_rtx (REG, Pmode, STRUCT_VALUE_INCOMING_REGNUM);
#else
  struct_value_incoming_rtx = struct_value_rtx;
#endif
#endif

  static_chain_rtx = gen_rtx (REG, Pmode, STATIC_CHAIN_REGNUM);

#ifdef STATIC_CHAIN_INCOMING_REGNUM
  if (STATIC_CHAIN_INCOMING_REGNUM != STATIC_CHAIN_REGNUM)
    static_chain_incoming_rtx = gen_rtx (REG, Pmode, STATIC_CHAIN_INCOMING_REGNUM);
  else
#endif
    static_chain_incoming_rtx = static_chain_rtx;

  if (FRAME_POINTER_REGNUM == ARG_POINTER_REGNUM)
    arg_pointer_rtx = frame_pointer_rtx;
  else
    arg_pointer_rtx = gen_rtx (REG, Pmode, ARG_POINTER_REGNUM);
}