final.c

早期freebsd实现


/* The final scan for one insn, INSN.
   Args are same as in `final', except that INSN
   is the insn being scanned.
   Value returned is the next insn to be scanned.

   NOPEEPHOLES is the flag to disallow peephole processing (currently
   used for within delayed branch sequence output).  */

rtx
final_scan_insn (insn, file, optimize, prescan, nopeepholes)
     rtx insn;
     FILE *file;
     int optimize;
     int prescan;
     int nopeepholes;
{
  register int i;
  insn_counter++;

  /* Ignore deleted insns.  These can occur when we split insns (due to a
     template of "#") while not optimizing.  */
  if (INSN_DELETED_P (insn))
    return NEXT_INSN (insn);

  switch (GET_CODE (insn))
    {
    case NOTE:
      if (prescan > 0)
	break;

      /* Align the beginning of a loop, for higher speed
	 on certain machines.  */

      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG && optimize > 0)
	{
#ifdef ASM_OUTPUT_LOOP_ALIGN
	  rtx next = next_nonnote_insn (insn);
	  if (next && GET_CODE (next) == CODE_LABEL)
	    {
	      ASM_OUTPUT_LOOP_ALIGN (asm_out_file);
	    }
#endif
	  break;
	}
      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
	break;

      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_PROLOGUE_END)
	{
#ifdef FUNCTION_END_PROLOGUE
	  FUNCTION_END_PROLOGUE (file);
#endif
	  profile_after_prologue (file);
	  break;
	}

#ifdef FUNCTION_BEGIN_EPILOGUE
      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EPILOGUE_BEG)
	{
	  FUNCTION_BEGIN_EPILOGUE (file);
	  break;
	}
#endif

      if (write_symbols == NO_DEBUG)
	break;
      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG)
	{
#ifdef SDB_DEBUGGING_INFO
	  if (write_symbols == SDB_DEBUG)
	    sdbout_begin_function (last_linenum);
#endif
#ifdef XCOFF_DEBUGGING_INFO
	  if (write_symbols == XCOFF_DEBUG)
	    xcoffout_begin_function (file, last_linenum);
#endif
#ifdef DWARF_DEBUGGING_INFO
	  if (write_symbols == DWARF_DEBUG)
	    dwarfout_begin_function ();
#endif
	  break;
	}
      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_DELETED)
	break;			/* An insn that was "deleted" */
      if (app_on)
	{
	  fprintf (file, ASM_APP_OFF);
	  app_on = 0;
	}
      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
	  && (debug_info_level == DINFO_LEVEL_NORMAL
	      || debug_info_level == DINFO_LEVEL_VERBOSE
#ifdef DWARF_DEBUGGING_INFO
	      || write_symbols == DWARF_DEBUG
#endif
	     )
	 )
	{
	  /* Beginning of a symbol-block.  Assign it a sequence number
	     and push the number onto the stack PENDING_BLOCKS.  */

	  if (block_depth == max_block_depth)
	    {
	      /* PENDING_BLOCKS is full; make it longer.  */
	      max_block_depth *= 2;
	      pending_blocks
		= (int *) xrealloc (pending_blocks,
				    max_block_depth * sizeof (int));
	    }
	  pending_blocks[block_depth++] = next_block_index;

	  /* Output debugging info about the symbol-block beginning.  */

#ifdef SDB_DEBUGGING_INFO
	  if (write_symbols == SDB_DEBUG)
	    sdbout_begin_block (file, last_linenum, next_block_index);
#endif
#ifdef XCOFF_DEBUGGING_INFO
	  if (write_symbols == XCOFF_DEBUG)
	    xcoffout_begin_block (file, last_linenum, next_block_index);
#endif
#ifdef DBX_DEBUGGING_INFO
	  if (write_symbols == DBX_DEBUG)
	    ASM_OUTPUT_INTERNAL_LABEL (file, "LBB", next_block_index);
#endif
#ifdef DWARF_DEBUGGING_INFO
	  if (write_symbols == DWARF_DEBUG && block_depth > 1)
	    dwarfout_begin_block (next_block_index);
#endif

	  next_block_index++;
	}
      else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
	       && (debug_info_level == DINFO_LEVEL_NORMAL
		   || debug_info_level == DINFO_LEVEL_VERBOSE
#ifdef DWARF_DEBUGGING_INFO
	           || write_symbols == DWARF_DEBUG
#endif
	          )
	      )
	{
	  /* End of a symbol-block.  Pop its sequence number off
	     PENDING_BLOCKS and output debugging info based on that.  */

	  --block_depth;

#ifdef XCOFF_DEBUGGING_INFO
	  if (write_symbols == XCOFF_DEBUG && block_depth >= 0)
	    xcoffout_end_block (file, last_linenum, pending_blocks[block_depth]);
#endif
#ifdef DBX_DEBUGGING_INFO
	  if (write_symbols == DBX_DEBUG && block_depth >= 0)
	    ASM_OUTPUT_INTERNAL_LABEL (file, "LBE",
				       pending_blocks[block_depth]);
#endif
#ifdef SDB_DEBUGGING_INFO
	  if (write_symbols == SDB_DEBUG && block_depth >= 0)
	    sdbout_end_block (file, last_linenum);
#endif
#ifdef DWARF_DEBUGGING_INFO
	  if (write_symbols == DWARF_DEBUG && block_depth >= 1)
	    dwarfout_end_block (pending_blocks[block_depth]);
#endif
	}
      else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_DELETED_LABEL
	       && (debug_info_level == DINFO_LEVEL_NORMAL
		   || debug_info_level == DINFO_LEVEL_VERBOSE))
	{
#ifdef DWARF_DEBUGGING_INFO
          if (write_symbols == DWARF_DEBUG)
            dwarfout_label (insn);
#endif
	}
      else if (NOTE_LINE_NUMBER (insn) > 0)
	/* This note is a line-number.  */
	{
	  register rtx note;

#if 0 /* This is what we used to do.  */
	  output_source_line (file, insn);
#endif
	  int note_after = 0;

	  /* If there is anything real after this note,
	     output it.  If another line note follows, omit this one.  */
	  for (note = NEXT_INSN (insn); note; note = NEXT_INSN (note))
	    {
	      if (GET_CODE (note) != NOTE && GET_CODE (note) != CODE_LABEL)
		break;
	      /* These types of notes can be significant
		 so make sure the preceding line number stays.  */
	      else if (GET_CODE (note) == NOTE
		       && (NOTE_LINE_NUMBER (note) == NOTE_INSN_BLOCK_BEG
			   || NOTE_LINE_NUMBER (note) == NOTE_INSN_BLOCK_END
			   || NOTE_LINE_NUMBER (note) == NOTE_INSN_FUNCTION_BEG))
  		break;
	      else if (GET_CODE (note) == NOTE && NOTE_LINE_NUMBER (note) > 0)
		{
		  /* Another line note follows; we can delete this note
		     if no intervening line numbers have notes elsewhere.  */
		  int num;
		  for (num = NOTE_LINE_NUMBER (insn) + 1;
		       num < NOTE_LINE_NUMBER (note);
		       num++)
		    if (line_note_exists[num])
		      break;

		  if (num >= NOTE_LINE_NUMBER (note))
		    note_after = 1;
		  break;
		}
	    }

	  /* Output this line note
	     if it is the first or the last line note in a row.  */
	  if (!note_after)
	    output_source_line (file, insn);
	}
      break;

    case BARRIER:
#ifdef ASM_OUTPUT_ALIGN_CODE
      /* Don't litter the assembler output with needless alignments.  A
	 BARRIER will be placed at the end of every function if HAVE_epilogue
	 is true.  */	 
      if (NEXT_INSN (insn))
	ASM_OUTPUT_ALIGN_CODE (file);
#endif
      break;

    case CODE_LABEL:
      CC_STATUS_INIT;
      if (prescan > 0)
	break;
      new_block = 1;
#ifdef SDB_DEBUGGING_INFO
      if (write_symbols == SDB_DEBUG && LABEL_NAME (insn))
	sdbout_label (insn);
#endif
#ifdef DWARF_DEBUGGING_INFO
      if (write_symbols == DWARF_DEBUG && LABEL_NAME (insn))
	dwarfout_label (insn);
#endif
      if (app_on)
	{
	  fprintf (file, ASM_APP_OFF);
	  app_on = 0;
	}
      if (NEXT_INSN (insn) != 0
	  && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN)
	{
	  rtx nextbody = PATTERN (NEXT_INSN (insn));

	  /* If this label is followed by a jump-table,
	     make sure we put the label in the read-only section.  Also
	     possibly write the label and jump table together.  */

	  if (GET_CODE (nextbody) == ADDR_VEC
	      || GET_CODE (nextbody) == ADDR_DIFF_VEC)
	    {
#ifndef JUMP_TABLES_IN_TEXT_SECTION
	      readonly_data_section ();
#ifdef READONLY_DATA_SECTION
	      ASM_OUTPUT_ALIGN (file,
				exact_log2 (BIGGEST_ALIGNMENT
					    / BITS_PER_UNIT));
#endif /* READONLY_DATA_SECTION */
#else /* JUMP_TABLES_IN_TEXT_SECTION */
	      text_section ();
#endif /* JUMP_TABLES_IN_TEXT_SECTION */
#ifdef ASM_OUTPUT_CASE_LABEL
	      ASM_OUTPUT_CASE_LABEL (file, "L", CODE_LABEL_NUMBER (insn),
				     NEXT_INSN (insn));
#else
	      ASM_OUTPUT_INTERNAL_LABEL (file, "L", CODE_LABEL_NUMBER (insn));
#endif
	      break;
	    }
	}

      ASM_OUTPUT_INTERNAL_LABEL (file, "L", CODE_LABEL_NUMBER (insn));
      break;

    default:
      {
	register rtx body = PATTERN (insn);
	int insn_code_number;
	char *template;
	rtx note;

	/* An INSN, JUMP_INSN or CALL_INSN.
	   First check for special kinds that recog doesn't recognize.  */

	if (GET_CODE (body) == USE /* These are just declarations */
	    || GET_CODE (body) == CLOBBER)
	  break;

#ifdef HAVE_cc0
	/* If there is a REG_CC_SETTER note on this insn, it means that
	   the setting of the condition code was done in the delay slot
	   of the insn that branched here.  So recover the cc status
	   from the insn that set it.  */

	note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX);
	if (note)
	  {
	    NOTICE_UPDATE_CC (PATTERN (XEXP (note, 0)), XEXP (note, 0));
	    cc_prev_status = cc_status;
	  }
#endif

	/* Detect insns that are really jump-tables
	   and output them as such.  */

	if (GET_CODE (body) == ADDR_VEC || GET_CODE (body) == ADDR_DIFF_VEC)
	  {
	    register int vlen, idx;

	    if (prescan > 0)
	      break;

	    if (app_on)
	      {
		fprintf (file, ASM_APP_OFF);
		app_on = 0;
	      }

	    vlen = XVECLEN (body, GET_CODE (body) == ADDR_DIFF_VEC);
	    for (idx = 0; idx < vlen; idx++)
	      {
		if (GET_CODE (body) == ADDR_VEC)
		  {
#ifdef ASM_OUTPUT_ADDR_VEC_ELT
		    ASM_OUTPUT_ADDR_VEC_ELT
		      (file, CODE_LABEL_NUMBER (XEXP (XVECEXP (body, 0, idx), 0)));
#else
		    abort ();
#endif
		  }
		else
		  {
#ifdef ASM_OUTPUT_ADDR_DIFF_ELT
		    ASM_OUTPUT_ADDR_DIFF_ELT
		      (file,
		       CODE_LABEL_NUMBER (XEXP (XVECEXP (body, 1, idx), 0)),
		       CODE_LABEL_NUMBER (XEXP (XEXP (body, 0), 0)));
#else
		    abort ();
#endif
		  }
	      }
#ifdef ASM_OUTPUT_CASE_END
	    ASM_OUTPUT_CASE_END (file,
				 CODE_LABEL_NUMBER (PREV_INSN (insn)),
				 insn);
#endif

	    text_section ();

	    break;
	  }

	/* Do basic-block profiling when we reach a new block.
	   Done here to avoid jump tables.  */
	if (profile_block_flag && new_block)
	  {
	    new_block = 0;
	    /* Enable the table of basic-block use counts
	       to point at the code it applies to.  */
	    ASM_OUTPUT_INTERNAL_LABEL (file, "LPB", count_basic_blocks);
	    /* Before first insn of this basic block, increment the
	       count of times it was entered.  */
#ifdef BLOCK_PROFILER
	    BLOCK_PROFILER (file, count_basic_blocks);
	    CC_STATUS_INIT;
#endif
	    count_basic_blocks++;
	  }

	if (GET_CODE (body) == ASM_INPUT)
	  {
	    /* There's no telling what that did to the condition codes.  */
	    CC_STATUS_INIT;
	    if (prescan > 0)
	      break;
	    if (! app_on)
	      {
		fprintf (file, ASM_APP_ON);
		app_on = 1;
	      }
	    fprintf (asm_out_file, "\t%s\n", XSTR (body, 0));
	    break;
	  }

	/* Detect `asm' construct with operands.  */
	if (asm_noperands (body) >= 0)
	  {
	    int noperands = asm_noperands (body);
	    rtx *ops;
	    char *string;

	    /* There's no telling what that did to the condition codes.  */
	    CC_STATUS_INIT;
	    if (prescan > 0)
	      break;

	    /* alloca won't do here, since only return from `final'
	       would free it.  */
	    if (noperands > 0)
	      ops = (rtx *) xmalloc (noperands * sizeof (rtx));

	    if (! app_on)
	      {
		fprintf (file, ASM_APP_ON);
		app_on = 1;
	      }

	    /* Get out the operand values.  */
	    string = decode_asm_operands (body, ops, NULL_PTR,
					  NULL_PTR, NULL_PTR);
	    /* Inhibit aborts on what would otherwise be compiler bugs.  */
	    insn_noperands = noperands;
	    this_is_asm_operands = insn;
	    /* Output the insn using them.  */
	    output_asm_insn (string, ops);
	    this_is_asm_operands = 0;
	    if (noperands > 0)
	      free (ops);
	    break;
	  }

	if (prescan <= 0 && app_on)
	  {
	    fprintf (file, ASM_APP_OFF);
	    app_on = 0;
	  }

	if (GET_CODE (body) == SEQUENCE)
	  {
	    /* A delayed-branch sequence */
	    register int i;
	    rtx next;

	    if (prescan > 0)
	      break;
	    final_sequence = body;

	    /* The first insn in this SEQUENCE might be a JUMP_INSN that will
	       force the restoration of a comparison that was previously
	       thought unnecessary.  If that happens, cancel this sequence
	       and cause that insn to be restored.  */

	    next = final_scan_insn (XVECEXP (body, 0, 0), file, 0, prescan, 1);
	    if (next != XVECEXP (body, 0, 1))
	      {
		final_sequence = 0;
		return next;
	      }

	    for (i = 1; i < XVECLEN (body, 0); i++)
	      final_scan_insn (XVECEXP (body, 0, i), file, 0, prescan, 1);
#ifdef DBR_OUTPUT_SEQEND
	    DBR_OUTPUT_SEQEND (file);
#endif
	    final_sequence = 0;

	    /* If the insn requiring the delay slot was a CALL_INSN, the
	       insns in the delay slot are actually executed before the
	       called function.  Hence we don't preserve any CC-setting
	       actions in these insns and the CC must be marked as being
	       clobbered by the function.  */
	    if (GET_CODE (XVECEXP (body, 0, 0)) == CALL_INSN)
	      CC_STATUS_INIT;

	    /* Following a conditional branch sequence, we have a new basic
	       block.  */
	    if (profile_block_flag)
	      {
		rtx insn = XVECEXP (body, 0, 0);
		rtx body = PATTERN (insn);

		if ((GET_CODE (insn) == JUMP_INSN && GET_CODE (body) == SET
		     && GET_CODE (SET_SRC (body)) != LABEL_REF)
		    || (GET_CODE (insn) == JUMP_INSN