498
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1 /*
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2 lwcc/cc-parse.c
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3
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4 Copyright © 2019 William Astle
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5
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6 This file is part of LWTOOLS.
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7
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8 LWTOOLS is free software: you can redistribute it and/or modify it under the
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9 terms of the GNU General Public License as published by the Free Software
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10 Foundation, either version 3 of the License, or (at your option) any later
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11 version.
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12
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13 This program is distributed in the hope that it will be useful, but WITHOUT
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14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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16 more details.
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17
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18 You should have received a copy of the GNU General Public License along with
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19 this program. If not, see <http://www.gnu.org/licenses/>.
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20 */
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21
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22 #include <string.h>
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23
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24 #include <lw_alloc.h>
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25 #include <lw_string.h>
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26
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27 #include "cpp.h"
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28 #include "tree.h"
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29
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30 #define TOK_KW_IF -1
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31 #define TOK_KW_ELSE -2
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32 #define TOK_KW_WHILE -3
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33 #define TOK_KW_DO -4
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34 #define TOK_KW_FOR -5
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35 #define TOK_KW_VOID -6
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36 #define TOK_KW_INT -7
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37 #define TOK_KW_CHAR -8
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38 #define TOK_KW_SHORT -9
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39 #define TOK_KW_LONG -10
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40 #define TOK_KW_UNSIGNED -11
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41 #define TOK_KW_SIGNED -12
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42 #define TOK_KW_FLOAT -13
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43 #define TOK_KW_DOUBLE -14
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44 #define TOK_KW_STRUCT -15
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45 #define TOK_KW_UNION -16
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46 #define TOK_KW_TYPEDEF -17
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47 #define TOK_KW_STATIC -18
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48 #define TOK_KW_SWITCH -19
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49 #define TOK_KW_CASE -20
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50 #define TOK_KW_DEFAULT -21
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51 #define TOK_KW_BREAK -22
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52 #define TOK_KW_CONTINUE -23
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53 #define TOK_KW_CONST -24
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54 #define TOK_KW_AUTO -25
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55 #define TOK_KW_ENUM -26
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56 #define TOK_KW_REGISTER -27
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57 #define TOK_KW_SIZEOF -28
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58 #define TOK_KW_VOLATILE -29
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59 #define TOK_KW_RETURN -30
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60 #define TOK_KW_EXTERN -31
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61 #define TOK_KW_GOTO -32
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62 #define TOK_TYPENAME -100
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63 #define TOK_CONST_INT -150
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64
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65 static struct { int tok; char *word; } keyword_list[] = {
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66 { TOK_KW_IF, "if" },
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67 { TOK_KW_ELSE, "else" },
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68 { TOK_KW_WHILE, "while" },
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69 { TOK_KW_DO, "do" },
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70 { TOK_KW_FOR, "for" },
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71 { TOK_KW_VOID, "void" },
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72 { TOK_KW_INT, "int" },
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73 { TOK_KW_CHAR, "char" },
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74 { TOK_KW_SHORT, "short" },
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75 { TOK_KW_LONG, "long" },
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76 { TOK_KW_UNSIGNED, "unsigned" },
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77 { TOK_KW_SIGNED, "signed" },
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78 { TOK_KW_FLOAT, "float" },
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79 { TOK_KW_DOUBLE, "double" },
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80 { TOK_KW_STRUCT, "struct" },
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81 { TOK_KW_UNION, "union" },
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82 { TOK_KW_TYPEDEF, "typedef" },
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83 { TOK_KW_STATIC, "static" },
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84 { TOK_KW_SWITCH, "switch" },
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85 { TOK_KW_CASE, "case" },
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86 { TOK_KW_DEFAULT, "default" },
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87 { TOK_KW_BREAK, "break" },
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88 { TOK_KW_CONTINUE, "continue" },
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89 { TOK_KW_CONST, "const" },
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90 { TOK_KW_AUTO, "auto" },
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91 { TOK_KW_ENUM, "enum" },
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92 { TOK_KW_REGISTER, "register" },
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93 { TOK_KW_SIZEOF, "sizeof" },
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94 { TOK_KW_VOLATILE, "volatile" },
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95 { TOK_KW_RETURN, "return" },
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96 { TOK_KW_EXTERN, "extern" },
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97 { TOK_KW_GOTO, "goto" },
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98 { TOK_NONE, "" }
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99 };
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100
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101
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102 struct parser_state
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103 {
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104 struct preproc_info *pp; // preprocessor data
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105 struct token *curtok; // the current token
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106 };
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107
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108
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109 struct token *parse_next(struct parser_state *ps)
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110 {
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111 struct token *tok;
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112 int i;
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113
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114 for (;;)
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115 {
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116 tok = preproc_next(ps -> pp);
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117 if (tok -> ttype == TOK_WSPACE)
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118 continue;
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119 if (tok -> ttype == TOK_EOL)
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120 continue;
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121 if (tok -> ttype == TOK_CHAR)
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122 {
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123 // random character
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124 fprintf(stderr, "Random character %02x\n", tok -> strval[0]);
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125 if (tok -> strval[0] < 32 || tok -> strval[0] > 126)
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126 continue;
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127 }
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128 break;
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129 }
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130 if (tok -> ttype == TOK_IDENT)
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131 {
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132 // convert identifier tokens to their respective meanings
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133 for (i = 0; keyword_list[i].tok != TOK_NONE; i++)
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134 {
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135 if (strcmp(keyword_list[i].word, tok -> strval) == 0)
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136 {
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137 tok -> ttype = keyword_list[i].tok;
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138 goto out;
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139 }
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140 }
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141 // check for registered types here
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142 }
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143 else if (tok -> ttype == TOK_NUMBER)
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144 {
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145 // look for anything that isn't 0-9
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146 for (i = 0; tok -> strval[i]; i++)
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147 {
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148 if (tok -> strval[i] < '0' || tok -> strval[i] > '9')
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149 break;
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150 }
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151 if (tok -> strval[i] == 0)
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152 tok -> ttype = TOK_CONST_INT;
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153 }
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154 out:
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155 fprintf(stderr, "Lexed: ");
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156 token_print(tok, stderr);
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157 fprintf(stderr, " (%d)\n", tok -> ttype);
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158 if (ps -> curtok)
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159 token_free(ps -> curtok);
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160 ps -> curtok = tok;
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161 return tok;
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162 }
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163
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164 void parse_generr(struct parser_state *ps, char *tag)
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165 {
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166 fprintf(stderr, "(%s) Unexpected token (%d): ", tag, ps -> curtok -> ttype);
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167 token_print(ps -> curtok, stderr);
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168 fprintf(stderr, "\n");
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169
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170 }
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171
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172 node_t *parse_expr(struct parser_state *ps)
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173 {
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174 node_t *rv;
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175 if (ps -> curtok -> ttype == TOK_CONST_INT)
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176 {
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177 rv = node_create(NODE_CONST_INT, ps -> curtok -> strval);
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178 parse_next(ps);
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179 return rv;
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180 }
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181 parse_generr(ps, "expr");
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182 return NULL;
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183 }
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184
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185 node_t *parse_statement(struct parser_state *ps)
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186 {
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187 node_t *rv;
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188 node_t *n;
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189
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190 switch (ps -> curtok -> ttype)
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191 {
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192 case TOK_KW_RETURN:
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193 parse_next(ps);
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194 n = parse_expr(ps);
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195 if (!n)
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196 {
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197 parse_generr(ps, "statement");
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198 return NULL;
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199 }
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200 rv = node_create(NODE_STMT_RETURN);
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201 node_addchild(rv, n);
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202 break;
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203
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204 default:
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205 return NULL;
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206 }
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207
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208 if (ps -> curtok -> ttype != TOK_EOS)
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209 parse_generr(ps, "statement");
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210 else
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211 parse_next(ps);
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212 return rv;
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213 }
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214
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215 node_t *parse_globaldecl(struct parser_state *ps)
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216 {
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217 node_t *rv = NULL;
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218 node_t *stmt;
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219 char *fnname = NULL;
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220 if (ps -> curtok -> ttype == TOK_KW_INT)
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221 {
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222 // variable name
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223 parse_next(ps);
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224 if (ps -> curtok -> ttype != TOK_IDENT)
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225 goto error;
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226 fnname = lw_strdup(ps -> curtok -> strval);
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227 parse_next(ps);
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228 if (ps -> curtok -> ttype != TOK_OPAREN)
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229 goto error;
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230 parse_next(ps);
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231 if (ps -> curtok -> ttype != TOK_CPAREN)
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232 goto error;
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233 parse_next(ps);
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234 if (ps -> curtok -> ttype != TOK_OBRACE)
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235 goto error;
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236 parse_next(ps);
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237 stmt = parse_statement(ps);
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238 if (!stmt)
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239 goto error;
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240 rv = node_create(NODE_FUNDEF, node_create(NODE_TYPE_INT), node_create(NODE_IDENT, fnname), node_create(NODE_FUNARGS), stmt);
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241 if (ps -> curtok -> ttype != TOK_CBRACE)
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242 goto error;
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243 parse_next(ps);
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244 lw_free(fnname);
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245 return rv;
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246 }
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247
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248
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249 error:
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250 if (fnname)
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251 lw_free(fnname);
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252 parse_generr(ps, "globaldecl");
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253 return rv;
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254 }
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255
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256 node_t *parse_program(struct preproc_info *pp)
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257 {
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258 node_t *rv;
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259 node_t *node;
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260 struct parser_state ps;
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261
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262 ps.pp = pp;
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263 ps.curtok = NULL;
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264
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265 rv = node_create(NODE_PROGRAM);
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266
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267 // prime the parser
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268 parse_next(&ps);
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269 while (ps.curtok -> ttype != TOK_EOF)
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270 {
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271 node = parse_globaldecl(&ps);
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272 if (!node)
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273 break;
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274 node_addchild(rv, node);
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275 }
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276
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277 return rv;
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278 }
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