final.c

这是完整的gcc源代码

     FILE *file;
     rtx insn;
     enum debugger write_symbols;
{
  register char *filename = NOTE_SOURCE_FILE (insn);

  last_linenum = NOTE_LINE_NUMBER (insn);

  if (write_symbols == GDB_DEBUG)
    {
      /* Output GDB-format line number info.  */

      /* If this is not the same source file as last time,
	 find or assign a GDB-file-number to this file.  */
      if (filename && (lastfile == 0 || strcmp (filename, lastfile)
		       || current_gdbfile == 0))
	set_current_gdbfile (filename);

      ++current_gdbfile->nlines;
      fprintf (file, "\t.gdbline %d,%d\n",
	       current_gdbfile->filenum, NOTE_LINE_NUMBER (insn));
    }

  if (write_symbols == SDB_DEBUG || write_symbols == DBX_DEBUG)
    {
#ifdef SDB_DEBUGGING_INFO
      if (write_symbols == SDB_DEBUG
#if 0 /* People like having line numbers even in wrong file!  */
	  /* COFF can't handle multiple source files--lose, lose.  */
	  && !strcmp (filename, main_input_filename)
#endif
	  /* COFF relative line numbers must be positive.  */
	  && last_linenum > sdb_begin_function_line)
	{
#ifdef ASM_OUTPUT_SOURCE_LINE
	  ASM_OUTPUT_SOURCE_LINE (file, last_linenum);
#else
	  fprintf (file, "\t.ln\t%d\n",
		   (sdb_begin_function_line
		    ? last_linenum - sdb_begin_function_line : 1));
#endif
	}
#endif

#ifdef DBX_DEBUGGING_INFO
      if (write_symbols == DBX_DEBUG)
	{
	  /* Write DBX line number data.  */

	  if (filename && (lastfile == 0 || strcmp (filename, lastfile)))
	    {
#ifdef ASM_OUTPUT_SOURCE_FILENAME
	      ASM_OUTPUT_SOURCE_FILENAME (file, filename);
#else
	      fprintf (file, "\t.stabs \"%s\",%d,0,0,Ltext\n",
		       filename, N_SOL);
#endif
	      lastfile = filename;
	    }
	}

#ifdef ASM_OUTPUT_SOURCE_LINE
      ASM_OUTPUT_SOURCE_LINE (file, NOTE_LINE_NUMBER (insn));
#else
      fprintf (file, "\t.stabd %d,0,%d\n",
	       N_SLINE, NOTE_LINE_NUMBER (insn));
#endif
#endif /* DBX_DEBUGGING_INFO */
    }
}

/* If X is a SUBREG, replace it with a REG or a MEM,
   based on the thing it is a subreg of.  */

rtx
alter_subreg (x)
     register rtx x;
{
  register rtx y = SUBREG_REG (x);
  if (GET_CODE (y) == SUBREG)
    y = alter_subreg (y);

  if (GET_CODE (y) == REG)
    {
      /* If the containing reg really gets a hard reg, so do we.  */
      PUT_CODE (x, REG);
      REGNO (x) = REGNO (y) + SUBREG_WORD (x);
    }
  else if (GET_CODE (y) == MEM)
    {
      register int offset = SUBREG_WORD (x) * UNITS_PER_WORD;
#ifdef BYTES_BIG_ENDIAN
      offset -= (min (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x)))
		 - min (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (y))));
#endif
      PUT_CODE (x, MEM);
      MEM_VOLATILE_P (x) = MEM_VOLATILE_P (y);
      XEXP (x, 0) = plus_constant (XEXP (y, 0), offset);
    }
  else if (GET_CODE (y) == CONST_DOUBLE)
    return y;

  return x;
}

/* Do alter_subreg on all the SUBREGs contained in X.  */

static rtx
walk_alter_subreg (x)
     rtx x;
{
  switch (GET_CODE (x))
    {
    case PLUS:
    case MULT:
      XEXP (x, 0) = walk_alter_subreg (XEXP (x, 0));
      XEXP (x, 1) = walk_alter_subreg (XEXP (x, 1));
      break;

    case MEM:
      XEXP (x, 0) = walk_alter_subreg (XEXP (x, 0));
      break;

    case SUBREG:
      return alter_subreg (x);
    }

  return x;
}

/* Given BODY, the body of a jump instruction, alter the jump condition
   as required by the bits that are set in cc_status.flags.
   Not all of the bits there can be handled at this level in all cases.

   The value is normally 0.
   1 means that the condition has become always true.
   -1 means that the condition has become always false.
   2 means that COND has been altered.  */

static int
alter_cond (cond)
     register rtx cond;
{
  int value = 0;

  if (cc_status.flags & CC_REVERSED)
    {
      value = 2;
      switch (GET_CODE (cond))
	{
	case LE:
	  PUT_CODE (cond, GE);
	  break;
	case GE:
	  PUT_CODE (cond, LE);
	  break;
	case LT:
	  PUT_CODE (cond, GT);
	  break;
	case GT:
	  PUT_CODE (cond, LT);
	  break;
	case LEU:
	  PUT_CODE (cond, GEU);
	  break;
	case GEU:
	  PUT_CODE (cond, LEU);
	  break;
	case LTU:
	  PUT_CODE (cond, GTU);
	  break;
	case GTU:
	  PUT_CODE (cond, LTU);
	  break;
	}
    }

  if (cc_status.flags & CC_NOT_POSITIVE)
    switch (GET_CODE (cond))
      {
      case LE:
      case LEU:
      case GEU:
	/* Jump becomes unconditional.  */
	return 1;

      case GT:
      case GTU:
      case LTU:
	/* Jump becomes no-op.  */
	return -1;

      case GE:
	PUT_CODE (cond, EQ);
	value = 2;
	break;

      case LT:
	PUT_CODE (cond, NE);
	value = 2;
	break;
      }

  if (cc_status.flags & CC_NOT_NEGATIVE)
    switch (GET_CODE (cond))
      {
      case GE:
      case GEU:
	/* Jump becomes unconditional.  */
	return 1;

      case LT:
      case LTU:
	/* Jump becomes no-op.  */
	return -1;

      case LE:
      case LEU:
	PUT_CODE (cond, EQ);
	value = 2;
	break;

      case GT:
      case GTU:
	PUT_CODE (cond, NE);
	value = 2;
	break;
      }

  if (cc_status.flags & CC_NO_OVERFLOW)
    switch (GET_CODE (cond))
      {
      case GEU:
	/* Jump becomes unconditional.  */
	return 1;

      case LEU:
	PUT_CODE (cond, EQ);
	value = 2;
	break;

      case GTU:
	PUT_CODE (cond, NE);
	value = 2;
	break;

      case LTU:
	/* Jump becomes no-op.  */
	return -1;
      }

  if (cc_status.flags & (CC_Z_IN_NOT_N | CC_Z_IN_N))
    switch (GET_CODE (cond))
      {
      case LE:
      case LEU:
      case GE:
      case GEU:
      case LT:
      case LTU:
      case GT:
      case GTU:
	abort ();

      case NE:
	PUT_CODE (cond, cc_status.flags & CC_Z_IN_N ? GE : LT);
	value = 2;
	break;

      case EQ:
	PUT_CODE (cond, cc_status.flags & CC_Z_IN_N ? LT : GE);
	value = 2;
	break;
      }
  
  return value;
}

/* Report inconsistency between the assembler template and the operands.
   In an `asm', it's the user's fault; otherwise, the compiler's fault.  */

static void
output_operand_lossage (str)
     char *str;
{
  if (this_is_asm_operands)
    error_for_asm (this_is_asm_operands, "invalid `asm': %s", str);
  else
    abort ();
}

/* Output of assembler code from a template, and its subroutines.  */

/* Output text from TEMPLATE to the assembler output file,
   obeying %-directions to substitute operands taken from
   the vector OPERANDS.

   %N (for N a digit) means print operand N in usual manner.
   %lN means require operand N to be a CODE_LABEL or LABEL_REF
      and print the label name with no punctuation.
   %cN means require operand N to be a constant
      and print the constant expression with no punctuation.
   %aN means expect operand N to be a memory address
      (not a memory reference!) and print a reference
      to that address.
   %nN means expect operand N to be a constant
      and print a constant expression for minus the value
      of the operand, with no other punctuation.  */

void
output_asm_insn (template, operands)
     char *template;
     rtx *operands;
{
  register char *p;
  register int c;

  /* An insn may return a null string template
     in a case where no assembler code is needed.  */
  if (*template == 0)
    return;

  p = template;
  putc ('\t', asm_out_file);

#ifdef ASM_OUTPUT_OPCODE
  ASM_OUTPUT_OPCODE (asm_out_file, p);
#endif

  while (c = *p++)
    {
#ifdef ASM_OUTPUT_OPCODE
      if (c == '\n')
	{
	  putc (c, asm_out_file);
	  while ((c = *p) == '\t')
	    {
	      putc (c, asm_out_file);
	      p++;
	    }
	  ASM_OUTPUT_OPCODE (asm_out_file, p);
	}
      else
#endif
      if (c != '%')
	putc (c, asm_out_file);
      else
	{
	  /* %% outputs a single %.  */
	  if (*p == '%')
	    {
	      p++;
	      putc (c, asm_out_file);
	    }
	  /* % followed by a letter and some digits
	     outputs an operand in a special way depending on the letter.
	     Letters `acln' are implemented here.
	     Other letters are passed to `output_operand' so that
	     the PRINT_OPERAND macro can define them.  */
	  else if ((*p >= 'a' && *p <= 'z')
		   || (*p >= 'A' && *p <= 'Z'))
	    {
	      int letter = *p++;
	      c = atoi (p);

	      if (! (*p >= '0' && *p <= '9'))
		output_operand_lossage ("operand number missing after %-letter");
	      else if (this_is_asm_operands && c >= (unsigned) insn_noperands)
		output_operand_lossage ("operand number out of range");
	      else if (letter == 'l')
		output_asm_label (operands[c]);
	      else if (letter == 'a')
		output_address (operands[c]);
	      else if (letter == 'c')
		{
		  if (CONSTANT_ADDRESS_P (operands[c]))
		    output_addr_const (asm_out_file, operands[c]);
		  else
		    output_operand (operands[c], 'c');
		}
	      else if (letter == 'n')
		{
		  if (GET_CODE (operands[c]) == CONST_INT)
		    fprintf (asm_out_file, "%d", - INTVAL (operands[c]));
		  else
		    {
		      putc ('-', asm_out_file);
		      output_addr_const (asm_out_file, operands[c]);
		    }
		}
	      else
		output_operand (operands[c], letter);

	      while ((c = *p) >= '0' && c <= '9') p++;
	    }
	  /* % followed by a digit outputs an operand the default way.  */
	  else if (*p >= '0' && *p <= '9')
	    {
	      c = atoi (p);
	      if (this_is_asm_operands && c >= (unsigned) insn_noperands)
		output_operand_lossage ("operand number out of range");
	      else
		output_operand (operands[c], 0);
	      while ((c = *p) >= '0' && c <= '9') p++;
	    }
	  /* % followed by punctuation: output something for that
	     punctuation character alone, with no operand.
	     The PRINT_OPERAND macro decides what is actually done.  */
#ifdef PRINT_OPERAND_PUNCT_VALID_P
	  else if (PRINT_OPERAND_PUNCT_VALID_P (*p))
	    output_operand (0, *p++);
#endif
	  else
	    output_operand_lossage ("invalid %%-code");
	}
    }

  putc ('\n', asm_out_file);
}

/* Output a LABEL_REF, or a bare CODE_LABEL, as an assembler symbol.  */

void
output_asm_label (x)
     rtx x;
{
  char buf[256];

  if (GET_CODE (x) == LABEL_REF)
    ASM_GENERATE_INTERNAL_LABEL (buf, "L", CODE_LABEL_NUMBER (XEXP (x, 0)));
  else if (GET_CODE (x) == CODE_LABEL)
    ASM_GENERATE_INTERNAL_LABEL (buf, "L", CODE_LABEL_NUMBER (x));
  else
    output_operand_lossage ("`%l' operand isn't a label");

  assemble_name (asm_out_file, buf);
}

/* Print operand X using machine-dependent assembler syntax.
   The macro PRINT_OPERAND is defined just to control this function.
   CODE is a non-digit that preceded the operand-number in the % spec,
   such as 'z' if the spec was `%z3'.  CODE is 0 if there was no char
   between the % and the digits.
   When CODE is a non-letter, X is 0.

   The meanings of the letters are machine-dependent and controlled
   by PRINT_OPERAND.  */

static void
output_operand (x, code)
     rtx x;
     int code;
{
  if (x && GET_CODE (x) == SUBREG)
    x = alter_subreg (x);
  PRINT_OPERAND (asm_out_file, x, code);
}

/* Print a memory reference operand for address X
   using machine-dependent assembler syntax.
   The macro PRINT_OPERAND_ADDRESS exists just to control this function.  */

void
output_address (x)
     rtx x;
{
  walk_alter_subreg (x);
  PRINT_OPERAND_ADDRESS (asm_out_file, x);
}

/* Print an integer constant expression in assembler syntax.
   Addition and subtraction are the only arithmetic
   that may appear in these expressions.  */

void
output_addr_const (file, x)
     FILE *file;
     rtx x;
{
  char buf[256];

 restart:
  switch (GET_CODE (x))
    {
    case SYMBOL_REF:
      assemble_name (file, XSTR (x, 0));
      break;

    case LABEL_REF:
      ASM_GENERATE_INTERNAL_LABEL (buf, "L", CODE_LABEL_NUMBER (XEXP (x, 0)));
      assemble_name (asm_out_file, buf);
      break;

    case CODE_LABEL:
      ASM_GENERATE_INTERNAL_LABEL (buf, "L", CODE_LABEL_NUMBER (x));
      assemble_name (asm_out_file, buf);
      break;

    case CONST_INT:
      fprintf (file, "%d", INTVAL (x));
      break;

    case CONST:
      x = XEXP (x, 0);
      goto restart;

    case CONST_DOUBLE:
      if (GET_MODE (x) == DImode)
	{
	  /* We can use %d if the number is <32 bits and positive.  */
	  if (CONST_DOUBLE_HIGH (x) || CONST_DOUBLE_LOW (x) < 0)
	    fprintf (file, "0x%x%08x",
		     CONST_DOUBLE_HIGH (x), CONST_DOUBLE_LOW (x));
	  else
	    fprintf (file, "%d", CONST_DOUBLE_LOW (x));
	}
      else
	/* We can't handle floating point constants;
	   PRINT_OPERAND must handle them.  */
	output_operand_lossage ("floating constant misused");
      break;

    case PLUS:
      /* Some assemblers need integer constants to appear last (eg masm).  */
      if (GET_CODE (XEXP (x, 0)) == CONST_INT)
	{
	  output_addr_const (file, XEXP (x, 1));
	  if (INTVAL (XEXP (x, 0)) >= 0)
	    fprintf (file, "+");
	  output_addr_const (file, XEXP (x, 0));
	}
      else
	{
	  output_addr_const (file, XEXP (x, 0));
	  if (INTVAL (XEXP (x, 1)) >= 0)
	    fprintf (file, "+");
	  output_addr_const (file, XEXP (x, 1));
	}
      break;

    case MINUS:
      output_addr_const (file, XEXP (x, 0));
      fprintf (file, "-");
      output_addr_const (file, XEXP (x, 1));
      break;

    default:
      output_operand_lossage ("invalid expression as operand");
    }
}