yacc.c

用C++编写的一个编译器

  int yychar;
  YYSTYPE yylval;
  int yynerrs;
#ifdef YYLSP_NEEDED
  YYLTYPE yylloc;
#endif
#endif

  YYSTYPE yyval;		/*  the variable used to return		*/
				/*  semantic values from the action	*/
				/*  routines				*/

  int yylen;

#if YYDEBUG != 0
  if (yydebug)
    fprintf(stderr, "Starting parse\n");
#endif

  yystate = 0;
  yyerrstatus = 0;
  yynerrs = 0;
  yychar = YYEMPTY;		/* Cause a token to be read.  */

  /* Initialize stack pointers.
     Waste one element of value and location stack
     so that they stay on the same level as the state stack.
     The wasted elements are never initialized.  */

  yyssp = yyss - 1;
  yyvsp = yyvs;
#ifdef YYLSP_NEEDED
  yylsp = yyls;
#endif

/* Push a new state, which is found in  yystate  .  */
/* In all cases, when you get here, the value and location stacks
   have just been pushed. so pushing a state here evens the stacks.  */
yynewstate:

  *++yyssp = yystate;

  if (yyssp >= yyss + yystacksize - 1)
    {
      /* Give user a chance to reallocate the stack */
      /* Use copies of these so that the &'s don't force the real ones into memory. */
      YYSTYPE *yyvs1 = yyvs;
      short *yyss1 = yyss;
#ifdef YYLSP_NEEDED
      YYLTYPE *yyls1 = yyls;
#endif

      /* Get the current used size of the three stacks, in elements.  */
      int size = yyssp - yyss + 1;

#ifdef yyoverflow
      /* Each stack pointer address is followed by the size of
	 the data in use in that stack, in bytes.  */
#ifdef YYLSP_NEEDED
      /* This used to be a conditional around just the two extra args,
	 but that might be undefined if yyoverflow is a macro.  */
      yyoverflow("parser stack overflow",
		 &yyss1, size * sizeof (*yyssp),
		 &yyvs1, size * sizeof (*yyvsp),
		 &yyls1, size * sizeof (*yylsp),
		 &yystacksize);
#else
      yyoverflow("parser stack overflow",
		 &yyss1, size * sizeof (*yyssp),
		 &yyvs1, size * sizeof (*yyvsp),
		 &yystacksize);
#endif

      yyss = yyss1; yyvs = yyvs1;
#ifdef YYLSP_NEEDED
      yyls = yyls1;
#endif
#else /* no yyoverflow */
      /* Extend the stack our own way.  */
      if (yystacksize >= YYMAXDEPTH)
	{
	  yyerror("parser stack overflow");
	  return 2;
	}
      yystacksize *= 2;
      if (yystacksize > YYMAXDEPTH)
	yystacksize = YYMAXDEPTH;
      yyss = (short *) alloca (yystacksize * sizeof (*yyssp));
      __yy_memcpy ((char *)yyss1, (char *)yyss, size * sizeof (*yyssp));
      yyvs = (YYSTYPE *) alloca (yystacksize * sizeof (*yyvsp));
      __yy_memcpy ((char *)yyvs1, (char *)yyvs, size * sizeof (*yyvsp));
#ifdef YYLSP_NEEDED
      yyls = (YYLTYPE *) alloca (yystacksize * sizeof (*yylsp));
      __yy_memcpy ((char *)yyls1, (char *)yyls, size * sizeof (*yylsp));
#endif
#endif /* no yyoverflow */

      yyssp = yyss + size - 1;
      yyvsp = yyvs + size - 1;
#ifdef YYLSP_NEEDED
      yylsp = yyls + size - 1;
#endif

#if YYDEBUG != 0
      if (yydebug)
	fprintf(stderr, "Stack size increased to %d\n", yystacksize);
#endif

      if (yyssp >= yyss + yystacksize - 1)
	YYABORT;
    }

#if YYDEBUG != 0
  if (yydebug)
    fprintf(stderr, "Entering state %d\n", yystate);
#endif

  goto yybackup;
 yybackup:

/* Do appropriate processing given the current state.  */
/* Read a lookahead token if we need one and don't already have one.  */
/* yyresume: */

  /* First try to decide what to do without reference to lookahead token.  */

  yyn = yypact[yystate];
  if (yyn == YYFLAG)
    goto yydefault;

  /* Not known => get a lookahead token if don't already have one.  */

  /* yychar is either YYEMPTY or YYEOF
     or a valid token in external form.  */

  if (yychar == YYEMPTY)
    {
#if YYDEBUG != 0
      if (yydebug)
	fprintf(stderr, "Reading a token: ");
#endif
      yychar = YYLEX;
    }

  /* Convert token to internal form (in yychar1) for indexing tables with */

  if (yychar <= 0)		/* This means end of input. */
    {
      yychar1 = 0;
      yychar = YYEOF;		/* Don't call YYLEX any more */

#if YYDEBUG != 0
      if (yydebug)
	fprintf(stderr, "Now at end of input.\n");
#endif
    }
  else
    {
      yychar1 = YYTRANSLATE(yychar);

#if YYDEBUG != 0
      if (yydebug)
	{
	  fprintf (stderr, "Next token is %d (%s", yychar, yytname[yychar1]);
	  /* Give the individual parser a way to print the precise meaning
	     of a token, for further debugging info.  */
#ifdef YYPRINT
	  YYPRINT (stderr, yychar, yylval);
#endif
	  fprintf (stderr, ")\n");
	}
#endif
    }

  yyn += yychar1;
  if (yyn < 0 || yyn > YYLAST || yycheck[yyn] != yychar1)
    goto yydefault;

  yyn = yytable[yyn];

  /* yyn is what to do for this token type in this state.
     Negative => reduce, -yyn is rule number.
     Positive => shift, yyn is new state.
       New state is final state => don't bother to shift,
       just return success.
     0, or most negative number => error.  */

  if (yyn < 0)
    {
      if (yyn == YYFLAG)
	goto yyerrlab;
      yyn = -yyn;
      goto yyreduce;
    }
  else if (yyn == 0)
    goto yyerrlab;

  if (yyn == YYFINAL)
    YYACCEPT;

  /* Shift the lookahead token.  */

#if YYDEBUG != 0
  if (yydebug)
    fprintf(stderr, "Shifting token %d (%s), ", yychar, yytname[yychar1]);
#endif

  /* Discard the token being shifted unless it is eof.  */
  if (yychar != YYEOF)
    yychar = YYEMPTY;

  *++yyvsp = yylval;
#ifdef YYLSP_NEEDED
  *++yylsp = yylloc;
#endif

  /* count tokens shifted since error; after three, turn off error status.  */
  if (yyerrstatus) yyerrstatus--;

  yystate = yyn;
  goto yynewstate;

/* Do the default action for the current state.  */
yydefault:

  yyn = yydefact[yystate];
  if (yyn == 0)
    goto yyerrlab;

/* Do a reduction.  yyn is the number of a rule to reduce with.  */
yyreduce:
  yylen = yyr2[yyn];
  if (yylen > 0)
    yyval = yyvsp[1-yylen]; /* implement default value of the action */

#if YYDEBUG != 0
  if (yydebug)
    {
      int i;

      fprintf (stderr, "Reducing via rule %d (line %d), ",
	       yyn, yyrline[yyn]);

      /* Print the symbols being reduced, and their result.  */
      for (i = yyprhs[yyn]; yyrhs[i] > 0; i++)
	fprintf (stderr, "%s ", yytname[yyrhs[i]]);
      fprintf (stderr, " -> %s\n", yytname[yyr1[yyn]]);
    }
#endif


  switch (yyn) {

case 5:
#line 91 "yacc.y"
{
			global_define(yyvsp[-1].st, yyvsp[0].sym);			
			prepare_local(yyvsp[0].sym);
		;
    break;}
case 6:
#line 96 "yacc.y"
{
			gen_funcbody(yyvsp[0].stmt);
			exit_local();
		;
    break;}
case 7:
#line 104 "yacc.y"
{
			global_define(yyvsp[0].stmt->spec, yyvsp[0].stmt->declist);
		;
    break;}
case 8:
#line 111 "yacc.y"
{
			yyval.stmt=newDeclStmt(yyvsp[-1].st, NULL, currentfile, lineno);
		;
    break;}
case 9:
#line 115 "yacc.y"
{
			yyval.stmt=newDeclStmt(yyvsp[-2].st, yyvsp[-1].sym, currentfile, lineno);
		;
    break;}
case 10:
#line 122 "yacc.y"
{
			yyval.st = newSuperType(UNKNOWN, yyvsp[0].type);
		;
    break;}
case 11:
#line 126 "yacc.y"
{
			yyval.st = newSuperType(yyvsp[-1].sc, yyvsp[0].type);
		;
    break;}
case 12:
#line 133 "yacc.y"
{yyval.sc=sc_typedef;;
    break;}
case 13:
#line 135 "yacc.y"
{yyval.sc=sc_external;;
    break;}
case 14:
#line 137 "yacc.y"
{yyval.sc=sc_static;;
    break;}
case 15:
#line 139 "yacc.y"
{yyval.sc=sc_auto;;
    break;}
case 16:
#line 141 "yacc.y"
{yyval.sc = sc_register;;
    break;}
case 17:
#line 146 "yacc.y"
{yyval.type=newType(NULL, yyvsp[0].bt, NULL);;
    break;}
case 18:
#line 148 "yacc.y"
{yyval.type=yyvsp[0].type;;
    break;}
case 19:
#line 150 "yacc.y"
{yyval.type=newType(NULL, bt_long, NULL);;
    break;}
case 20:
#line 152 "yacc.y"
{yyval.type=yyvsp[0].type;;
    break;}
case 21:
#line 157 "yacc.y"
{yyval.bt=yyvsp[0].bt;;
    break;}
case 22:
#line 159 "yacc.y"
{yyval.bt=check_basictype(yyvsp[-1].bt, yyvsp[0].bt);;
    break;}
case 23:
#line 164 "yacc.y"
{yyval.bt = bt_void;;
    break;}
case 24:
#line 166 "yacc.y"
{yyval.bt = bt_char;;
    break;}
case 25:
#line 168 "yacc.y"
{yyval.bt = bt_short;;
    break;}
case 26:
#line 170 "yacc.y"
{yyval.bt = bt_int;;
    break;}
case 27:
#line 172 "yacc.y"
{yyval.bt = bt_unsignedint;;
    break;}
case 28:
#line 174 "yacc.y"
{yyval.bt = bt_long;;
    break;}
case 29:
#line 176 "yacc.y"
{yyval.bt = bt_int;;
    break;}
case 30:
#line 178 "yacc.y"
{yyval.bt = bt_float;;
    break;}
case 31:
#line 180 "yacc.y"
{yyval.bt = bt_double;;
    break;}
case 32:
#line 182 "yacc.y"
{yyval.bt = bt_long;;
    break;}
case 33:
#line 187 "yacc.y"
{
			Type *one = newType(yyvsp[0].val.s, yyvsp[-1].bt, NULL);
			//maybe one is not true
			yyval.type=add_newType(one);
		;
    break;}
case 34:
#line 193 "yacc.y"
{
			yyval.type=yyvsp[-3].type;
			yyval.type->memlist = member_declare(yyvsp[-5].bt, yyvsp[-1].stmt, &(yyval.type->size));
		;
    break;}
case 35:
#line 198 "yacc.y"
{
			yyval.type = newType(NULL, yyvsp[-3].bt, NULL);
			yyval.type->memlist = member_declare(yyvsp[-3].bt, yyvsp[-1].stmt, &(yyval.type->size));
		;
    break;}
case 36:
#line 203 "yacc.y"
{
			Type *one = newType(yyvsp[0].val.s, yyvsp[-1].bt, NULL);
			yyval.type=add_newType(one);
		;
    break;}
case 37:
#line 211 "yacc.y"
{yyval.bt=bt_struct;;
    break;}