gen.c

这是一个软件水平资格考试中使用的CASL汇编语言的编译器,实现文件中包括一个编译器,一个虚拟机,一个类似于Debug的调试器.

		outc( '\n' );
		indent_puts( "yy_current_state = -yy_current_state;" );
		}

	else if ( fullspd )
		{
		indent_puts( "{" );	/* } for vi */
		indent_puts(
		"register yyconst struct yy_trans_info *yy_trans_info;\n" );
		indent_puts( "register YY_CHAR yy_c;\n" );
		indent_put2s( "for ( yy_c = %s;", char_map );
		indent_puts(
	"      (yy_trans_info = &yy_current_state[(unsigned int) yy_c])->" );
		indent_puts( "yy_verify == yy_c;" );
		indent_put2s( "      yy_c = %s )", char_map_2 );

		indent_up();

		if ( num_backing_up > 0 )
			indent_puts( "{" );	/* } for vi */

		indent_puts( "yy_current_state += yy_trans_info->yy_nxt;" );

		if ( num_backing_up > 0 )
			{
			outc( '\n' );
			gen_backing_up();	/* { for vi */
			indent_puts( "}" );
			}

		indent_down();	/* { for vi */
		indent_puts( "}" );
		}

	else
		{ /* compressed */
		indent_puts( "do" );

		indent_up();
		indent_puts( "{" );	/* } for vi */

		gen_next_state( false );

		indent_puts( "++yy_cp;" );

		/* { for vi */
		indent_puts( "}" );
		indent_down();

		do_indent();

		if ( interactive )
			out_dec( "while ( yy_base[yy_current_state] != %d );\n",
				jambase );
		else
			out_dec( "while ( yy_current_state != %d );\n",
				jamstate );

		if ( ! reject && ! interactive )
			{
			/* Do the guaranteed-needed backing up to figure out
			 * the match.
			 */
			indent_puts( "yy_cp = yy_last_accepting_cpos;" );
			indent_puts(
				"yy_current_state = yy_last_accepting_state;" );
			}
		}
	}


/* Generate the code to find the next state. */

void gen_next_state( worry_about_NULs )
int worry_about_NULs;
	{ /* NOTE - changes in here should be reflected in gen_next_match() */
	char char_map[256];

	if ( worry_about_NULs && ! nultrans )
		{
		if ( useecs )
			(void) sprintf( char_map,
				"(*yy_cp ? yy_ec[YY_SC_TO_UI(*yy_cp)] : %d)",
					NUL_ec );
		else
			(void) sprintf( char_map,
				"(*yy_cp ? YY_SC_TO_UI(*yy_cp) : %d)", NUL_ec );
		}

	else
		strcpy( char_map, useecs ?
			"yy_ec[YY_SC_TO_UI(*yy_cp)]" : "YY_SC_TO_UI(*yy_cp)" );

	if ( worry_about_NULs && nultrans )
		{
		if ( ! fulltbl && ! fullspd )
			/* Compressed tables back up *before* they match. */
			gen_backing_up();

		indent_puts( "if ( *yy_cp )" );
		indent_up();
		indent_puts( "{" );	/* } for vi */
		}

	if ( fulltbl )
		indent_put2s(
			"yy_current_state = yy_nxt[yy_current_state][%s];", 
				char_map );

	else if ( fullspd )
		indent_put2s(
			"yy_current_state += yy_current_state[%s].yy_nxt;",
				char_map );

	else
		gen_next_compressed_state( char_map );

	if ( worry_about_NULs && nultrans )
		{
		/* { for vi */
		indent_puts( "}" );
		indent_down();
		indent_puts( "else" );
		indent_up();
		indent_puts(
			"yy_current_state = yy_NUL_trans[yy_current_state];" );
		indent_down();
		}

	if ( fullspd || fulltbl )
		gen_backing_up();

	if ( reject )
		indent_puts( "*yy_state_ptr++ = yy_current_state;" );
	}


/* Generate the code to make a NUL transition. */

void gen_NUL_trans()
	{ /* NOTE - changes in here should be reflected in gen_next_match() */
	/* Only generate a definition for "yy_cp" if we'll generate code
	 * that uses it.  Otherwise lint and the like complain.
	 */
	int need_backing_up = (num_backing_up > 0 && ! reject);

	if ( need_backing_up && (! nultrans || fullspd || fulltbl) )
		/* We're going to need yy_cp lying around for the call
		 * below to gen_backing_up().
		 */
		indent_puts( "register char *yy_cp = yy_c_buf_p;" );

	outc( '\n' );

	if ( nultrans )
		{
		indent_puts(
			"yy_current_state = yy_NUL_trans[yy_current_state];" );
		indent_puts( "yy_is_jam = (yy_current_state == 0);" );
		}

	else if ( fulltbl )
		{
		do_indent();
		out_dec( "yy_current_state = yy_nxt[yy_current_state][%d];\n",
			NUL_ec );
		indent_puts( "yy_is_jam = (yy_current_state <= 0);" );
		}

	else if ( fullspd )
		{
		do_indent();
		out_dec( "register int yy_c = %d;\n", NUL_ec );

		indent_puts(
		"register yyconst struct yy_trans_info *yy_trans_info;\n" );
		indent_puts(
		"yy_trans_info = &yy_current_state[(unsigned int) yy_c];" );
		indent_puts( "yy_current_state += yy_trans_info->yy_nxt;" );

		indent_puts(
			"yy_is_jam = (yy_trans_info->yy_verify != yy_c);" );
		}

	else
		{
		char NUL_ec_str[20];

		(void) sprintf( NUL_ec_str, "%d", NUL_ec );
		gen_next_compressed_state( NUL_ec_str );

		if ( reject )
			indent_puts( "*yy_state_ptr++ = yy_current_state;" );

		do_indent();

		out_dec( "yy_is_jam = (yy_current_state == %d);\n", jamstate );
		}

	/* If we've entered an accepting state, back up; note that
	 * compressed tables have *already* done such backing up, so
	 * we needn't bother with it again.
	 */
	if ( need_backing_up && (fullspd || fulltbl) )
		{
		outc( '\n' );
		indent_puts( "if ( ! yy_is_jam )" );
		indent_up();
		indent_puts( "{" );
		gen_backing_up();
		indent_puts( "}" );
		indent_down();
		}
	}


/* Generate the code to find the start state. */

void gen_start_state()
	{
	if ( fullspd )
		{
		if ( bol_needed )
			{
			indent_puts(
	"yy_current_state = yy_start_state_list[yy_start + YY_AT_BOL()];" );
			}
		else
			indent_puts(
			"yy_current_state = yy_start_state_list[yy_start];" );
		}

	else
		{
		indent_puts( "yy_current_state = yy_start;" );

		if ( bol_needed )
			indent_puts( "yy_current_state += YY_AT_BOL();" );

		if ( reject )
			{
			/* Set up for storing up states. */
			indent_puts( "yy_state_ptr = yy_state_buf;" );
			indent_puts( "*yy_state_ptr++ = yy_current_state;" );
			}
		}
	}


/* gentabs - generate data statements for the transition tables */

void gentabs()
	{
	int i, j, k, *accset, nacc, *acc_array, total_states;
	int end_of_buffer_action = num_rules + 1;

	acc_array = allocate_integer_array( current_max_dfas );
	nummt = 0;

	/* The compressed table format jams by entering the "jam state",
	 * losing information about the previous state in the process.
	 * In order to recover the previous state, we effectively need
	 * to keep backing-up information.
	 */
	++num_backing_up;

	if ( reject )
		{
		/* Write out accepting list and pointer list.
		 *
		 * First we generate the "yy_acclist" array.  In the process,
		 * we compute the indices that will go into the "yy_accept"
		 * array, and save the indices in the dfaacc array.
		 */
		int EOB_accepting_list[2];

		/* Set up accepting structures for the End Of Buffer state. */
		EOB_accepting_list[0] = 0;
		EOB_accepting_list[1] = end_of_buffer_action;
		accsiz[end_of_buffer_state] = 1;
		dfaacc[end_of_buffer_state].dfaacc_set = EOB_accepting_list;

		out_str_dec( long_align ? C_long_decl : C_short_decl,
			"yy_acclist", MAX( numas, 1 ) + 1 );

		j = 1;	/* index into "yy_acclist" array */

		for ( i = 1; i <= lastdfa; ++i )
			{
			acc_array[i] = j;

			if ( accsiz[i] != 0 )
				{
				accset = dfaacc[i].dfaacc_set;
				nacc = accsiz[i];

				if ( trace )
					fprintf( stderr,
						_( "state # %d accepts: " ),
						i );

				for ( k = 1; k <= nacc; ++k )
					{
					int accnum = accset[k];

					++j;

					if ( variable_trailing_context_rules &&
					  ! (accnum & YY_TRAILING_HEAD_MASK) &&
					   accnum > 0 && accnum <= num_rules &&
					  rule_type[accnum] == RULE_VARIABLE )
						{
						/* Special hack to flag
						 * accepting number as part
						 * of trailing context rule.
						 */
						accnum |= YY_TRAILING_MASK;
						}

					mkdata( accnum );

					if ( trace )
						{
						fprintf( stderr, "[%d]",
							accset[k] );

						if ( k < nacc )
							fputs( ", ", stderr );
						else
							putc( '\n', stderr );
						}
					}
				}
			}

		/* add accepting number for the "jam" state */
		acc_array[i] = j;

		dataend();
		}

	else
		{
		dfaacc[end_of_buffer_state].dfaacc_state = end_of_buffer_action;

		for ( i = 1; i <= lastdfa; ++i )
			acc_array[i] = dfaacc[i].dfaacc_state;

		/* add accepting number for jam state */
		acc_array[i] = 0;
		}

	/* Spit out "yy_accept" array.  If we're doing "reject", it'll be
	 * pointers into the "yy_acclist" array.  Otherwise it's actual
	 * accepting numbers.  In either case, we just dump the numbers.
	 */

	/* "lastdfa + 2" is the size of "yy_accept"; includes room for C arrays
	 * beginning at 0 and for "jam" state.
	 */
	k = lastdfa + 2;

	if ( reject )
		/* We put a "cap" on the table associating lists of accepting
		 * numbers with state numbers.  This is needed because we tell
		 * where the end of an accepting list is by looking at where
		 * the list for the next state starts.
		 */
		++k;

	out_str_dec( long_align ? C_long_decl : C_short_decl, "yy_accept", k );

	for ( i = 1; i <= lastdfa; ++i )
		{
		mkdata( acc_array[i] );

		if ( ! reject && trace && acc_array[i] )
			fprintf( stderr, _( "state # %d accepts: [%d]\n" ),
				i, acc_array[i] );
		}

	/* Add entry for "jam" state. */
	mkdata( acc_array[i] );

	if ( reject )
		/* Add "cap" for the list. */
		mkdata( acc_array[i] );

	dataend();

	if ( useecs )
		genecs();

	if ( usemecs )
		{
		/* Write out meta-equivalence classes (used to index
		 * templates with).
		 */

		if ( trace )
			fputs( _( "\n\nMeta-Equivalence Classes:\n" ),
			      stderr );

		out_str_dec( C_int_decl, "yy_meta", numecs + 1 );

		for ( i = 1; i <= numecs; ++i )
			{
			if ( trace )
				fprintf( stderr, "%d = %d\n",
					i, ABS( tecbck[i] ) );

			mkdata( ABS( tecbck[i] ) );
			}

		dataend();
		}

	total_states = lastdfa + numtemps;

	out_str_dec( (tblend >= MAX_SHORT || long_align) ?
			C_long_decl : C_short_decl,
		"yy_base", total_states + 1 );

	for ( i = 1; i <= lastdfa; ++i )
		{
		register int d = def[i];

		if ( base[i] == JAMSTATE )
			base[i] = jambase;

		if ( d == JAMSTATE )
			def[i] = jamstate;

		else if ( d < 0 )
			{
			/* Template reference. */
			++tmpuses;
			def[i] = lastdfa - d + 1;
			}

		mkdata( base[i] );
		}

	/* Generate jam state's base index. */
	mkdata( base[i] );

	for ( ++i /* skip jam state */; i <= total_states; ++i )
		{
		mkdata( base[i] );
		def[i] = jamstate;
		}

	dataend();

	out_str_dec( (total_states >= MAX_SHORT || long_align) ?
			C_long_decl : C_short_decl,
		"yy_def", total_states + 1 );

	for ( i = 1; i <= total_states; ++i )
		mkdata( def[i] );

	dataend();

	out_str_dec( (total_states >= MAX_SHORT || long_align) ?
			C_long_decl : C_short_decl,
		"yy_nxt", tblend + 1 );

	for ( i = 1; i <= tblend; ++i )
		{
		/* Note, the order of the following test is important.
		 * If chk[i] is 0, then nxt[i] is undefined.
		 */
		if ( chk[i] == 0 || nxt[i] == 0 )
			nxt[i] = jamstate;	/* new state is the JAM state */

		mkdata( nxt[i] );
		}

	dataend();

	out_str_dec( (total_states >= MAX_SHORT || long_align) ?
			C_long_decl : C_short_decl,
		"yy_chk", tblend + 1 );

	for ( i = 1; i <= tblend; ++i )
		{
		if ( chk[i] == 0 )
			++nummt;

		mkdata( chk[i] );
		}

	dataend();
	}


/* Write out a formatted string (with a secondary string argument) at the
 * current indentation level, adding a final newline.
 */

void indent_put2s( fmt, arg )
char fmt[], arg[];
	{
	do_indent();
	out_str( fmt, arg );
	outn( "" );
	}


/* Write out a string at the current indentation level, adding a final
 * newline.
 */

void indent_puts( str )
char str[];
	{
	do_indent();
	outn( str );
	}


/* make_tables - generate transition tables and finishes generating output file
 */