gcc/go/gofrontend/parse.h

   1 // parse.h -- Go frontend parser.     -*- C++ -*-
   2
   3 // Copyright 2009 The Go Authors. All rights reserved.
   4 // Use of this source code is governed by a BSD-style
   5 // license that can be found in the LICENSE file.
   6
   7 #ifndef GO_PARSE_H
   8 #define GO_PARSE_H
   9
  10 class Set_iota_traverse;
  11 class Lex;
  12 class Gogo;
  13 class Named_object;
  14 class Type;
  15 class Typed_identifier;
  16 class Typed_identifier_list;
  17 class Channel_type;
  18 class Function_type;
  19 class Block;
  20 class Expression;
  21 class Expression_list;
  22 class Struct_field_list;
  23 class Case_clauses;
  24 class Type_case_clauses;
  25 class Select_clauses;
  26 class Statement;
  27 class Label;
  28
  29 // Parse the program.
  30
  31 class Parse
  32 {
  33  public:
  34   Parse(Lex*, Gogo*);
  35
  36   // Parse a program.
  37   void
  38   program();
  39
  40  private:
  41   // Precedence values.
  42   enum Precedence
  43   {
  44     PRECEDENCE_INVALID = -1,
  45     PRECEDENCE_NORMAL = 0,
  46     PRECEDENCE_OROR,
  47     PRECEDENCE_ANDAND,
  48     PRECEDENCE_RELOP,
  49     PRECEDENCE_ADDOP,
  50     PRECEDENCE_MULOP
  51   };
  52
  53   // We use this when parsing the range clause of a for statement.
  54   struct Range_clause
  55   {
  56     // Set to true if we found a range clause.
  57     bool found;
  58     // The index expression.
  59     Expression* index;
  60     // The value expression.
  61     Expression* value;
  62     // The range expression.
  63     Expression* range;
  64
  65     Range_clause()
  66       : found(false), index(NULL), value(NULL), range(NULL)
  67     { }
  68   };
  69
  70   // We use this when parsing the statement at the start of a switch,
  71   // in order to recognize type switches.
  72   struct Type_switch
  73   {
  74     // Set to true if we find a type switch.
  75     bool found;
  76     // The variable name.
  77     std::string name;
  78     // The location of the variable.
  79     Location location;
  80     // The expression.
  81     Expression* expr;
  82
  83     Type_switch()
  84       : found(false), name(), location(UNKNOWN_LOCATION), expr(NULL)
  85     { }
  86   };
  87
  88   // A variable defined in an enclosing function referenced by the
  89   // current function.
  90   class Enclosing_var
  91   {
  92    public:
  93     Enclosing_var(Named_object* var, Named_object* in_function,
  94                   unsigned int index)
  95       : var_(var), in_function_(in_function), index_(index)
  96     { }
  97
  98     // We put these in a vector, so we need a default constructor.
  99     Enclosing_var()
 100       : var_(NULL), in_function_(NULL), index_(-1U)
 101     { }
 102
 103     Named_object*
 104     var() const
 105     { return this->var_; }
 106
 107     Named_object*
 108     in_function() const
 109     { return this->in_function_; }
 110
 111     unsigned int
 112     index() const
 113     { return this->index_; }
 114
 115    private:
 116     // The variable which is being referred to.
 117     Named_object* var_;
 118     // The function where the variable is defined.
 119     Named_object* in_function_;
 120     // The index of the field in this function's closure struct for
 121     // this variable.
 122     unsigned int index_;
 123   };
 124
 125   // We store Enclosing_var entries in a set, so we need a comparator.
 126   struct Enclosing_var_comparison
 127   {
 128     bool
 129     operator()(const Enclosing_var&, const Enclosing_var&);
 130   };
 131
 132   // A set of Enclosing_var entries.
 133   typedef std::set<Enclosing_var, Enclosing_var_comparison> Enclosing_vars;
 134
 135   // Used to detect duplicate parameter/result names.
 136   typedef std::map<std::string, const Typed_identifier*> Names;
 137
 138   // Peek at the current token from the lexer.
 139   const Token*
 140   peek_token();
 141
 142   // Consume the current token, return the next one.
 143   const Token*
 144   advance_token();
 145
 146   // Push a token back on the input stream.
 147   void
 148   unget_token(const Token&);
 149
 150   // The location of the current token.
 151   Location
 152   location();
 153
 154   // For break and continue we keep a stack of statements with
 155   // associated labels (if any).  The top of the stack is used for a
 156   // break or continue statement with no label.
 157   typedef std::vector<std::pair<Statement*, Label*> > Bc_stack;
 158
 159   // Map from type switch variables to the variables they mask, so
 160   // that a use of the type switch variable can become a use of the
 161   // real variable.
 162   typedef Unordered_map(Named_object*, Named_object*) Type_switch_vars;
 163
 164   // Parser nonterminals.
 165   void identifier_list(Typed_identifier_list*);
 166   Expression_list* expression_list(Expression*, bool may_be_sink,
 167                                    bool may_be_composite_lit);
 168   bool qualified_ident(std::string*, Named_object**);
 169   Type* type();
 170   bool type_may_start_here();
 171   Type* type_name(bool issue_error);
 172   Type* array_type(bool may_use_ellipsis);
 173   Type* map_type();
 174   Type* struct_type();
 175   void field_decl(Struct_field_list*);
 176   Type* pointer_type();
 177   Type* channel_type();
 178   void check_signature_names(const Typed_identifier_list*, Names*);
 179   Function_type* signature(Typed_identifier*, Location);
 180   bool parameters(Typed_identifier_list**, bool* is_varargs);
 181   Typed_identifier_list* parameter_list(bool* is_varargs);
 182   void parameter_decl(bool, Typed_identifier_list*, bool*, bool*, bool*);
 183   bool result(Typed_identifier_list**);
 184   Location block();
 185   Type* interface_type();
 186   void method_spec(Typed_identifier_list*);
 187   void declaration();
 188   bool declaration_may_start_here();
 189   void decl(void (Parse::*)(void*), void*);
 190   void list(void (Parse::*)(void*), void*, bool);
 191   void const_decl();
 192   void const_spec(Type**, Expression_list**);
 193   void type_decl();
 194   void type_spec(void*);
 195   void var_decl();
 196   void var_spec(void*);
 197   void init_vars(const Typed_identifier_list*, Type*, Expression_list*,
 198                  bool is_coloneq, Location);
 199   bool init_vars_from_call(const Typed_identifier_list*, Type*, Expression*,
 200                            bool is_coloneq, Location);
 201   bool init_vars_from_map(const Typed_identifier_list*, Type*, Expression*,
 202                           bool is_coloneq, Location);
 203   bool init_vars_from_receive(const Typed_identifier_list*, Type*,
 204                               Expression*, bool is_coloneq, Location);
 205   bool init_vars_from_type_guard(const Typed_identifier_list*, Type*,
 206                                  Expression*, bool is_coloneq,
 207                                  Location);
 208   Named_object* init_var(const Typed_identifier&, Type*, Expression*,
 209                          bool is_coloneq, bool type_from_init, bool* is_new,
 210                          Expression_list* vars, Expression_list* vals);
 211   Named_object* create_dummy_global(Type*, Expression*, Location);
 212   void finish_init_vars(Expression_list* vars, Expression_list* vals,
 213                         Location);
 214   void simple_var_decl_or_assignment(const std::string&, Location,
 215                                      bool may_be_composite_lit,
 216                                      Range_clause*, Type_switch*);
 217   void function_decl(bool saw_nointerface);
 218   Typed_identifier* receiver();
 219   Expression* operand(bool may_be_sink, bool *is_parenthesized);
 220   Expression* enclosing_var_reference(Named_object*, Named_object*,
 221                                       Location);
 222   Expression* composite_lit(Type*, int depth, Location);
 223   Expression* function_lit();
 224   Expression* create_closure(Named_object* function, Enclosing_vars*,
 225                              Location);
 226   Expression* primary_expr(bool may_be_sink, bool may_be_composite_lit,
 227                            bool* is_type_switch, bool* is_parenthesized);
 228   Expression* selector(Expression*, bool* is_type_switch);
 229   Expression* index(Expression*);
 230   Expression* call(Expression*);
 231   Expression* expression(Precedence, bool may_be_sink,
 232                          bool may_be_composite_lit, bool* is_type_switch,
 233                          bool *is_parenthesized);
 234   bool expression_may_start_here();
 235   Expression* unary_expr(bool may_be_sink, bool may_be_composite_lit,
 236                          bool* is_type_switch, bool* is_parenthesized);
 237   Type* reassociate_chan_direction(Channel_type*, Location);
 238   Expression* qualified_expr(Expression*, Location);
 239   Expression* id_to_expression(const std::string&, Location, bool);
 240   void statement(Label*);
 241   bool statement_may_start_here();
 242   void labeled_stmt(const std::string&, Location);
 243   Expression* simple_stat(bool, bool*, Range_clause*, Type_switch*);
 244   bool simple_stat_may_start_here();
 245   void statement_list();
 246   bool statement_list_may_start_here();
 247   void expression_stat(Expression*);
 248   void send_stmt(Expression*);
 249   void inc_dec_stat(Expression*);
 250   void assignment(Expression*, bool may_be_composite_lit, Range_clause*);
 251   void tuple_assignment(Expression_list*, bool may_be_composite_lit,
 252                         Range_clause*);
 253   void send();
 254   void go_or_defer_stat();
 255   void return_stat();
 256   void if_stat();
 257   void switch_stat(Label*);
 258   Statement* expr_switch_body(Label*, Expression*, Location);
 259   void expr_case_clause(Case_clauses*, bool* saw_default);
 260   Expression_list* expr_switch_case(bool*);
 261   Statement* type_switch_body(Label*, const Type_switch&, Location);
 262   void type_case_clause(Named_object*, Type_case_clauses*, bool* saw_default);
 263   void type_switch_case(std::vector<Type*>*, bool*);
 264   void select_stat(Label*);
 265   void comm_clause(Select_clauses*, bool* saw_default);
 266   bool comm_case(bool*, Expression**, Expression**, Expression**,
 267                  std::string*, std::string*, bool*);
 268   bool send_or_recv_stmt(bool*, Expression**, Expression**, Expression**,
 269                          std::string*, std::string*);
 270   void for_stat(Label*);
 271   void for_clause(Expression**, Block**);
 272   void range_clause_decl(const Typed_identifier_list*, Range_clause*);
 273   void range_clause_expr(const Expression_list*, Range_clause*);
 274   void push_break_statement(Statement*, Label*);
 275   void push_continue_statement(Statement*, Label*);
 276   void pop_break_statement();
 277   void pop_continue_statement();
 278   Statement* find_bc_statement(const Bc_stack*, const std::string&);
 279   void break_stat();
 280   void continue_stat();
 281   void goto_stat();
 282   void package_clause();
 283   void import_decl();
 284   void import_spec(void*);
 285
 286   void reset_iota();
 287   int iota_value();
 288   void increment_iota();
 289
 290   // Skip past an error looking for a semicolon or OP.  Return true if
 291   // all is well, false if we found EOF.
 292   bool
 293   skip_past_error(Operator op);
 294
 295   // Verify that an expression is not a sink, and return either the
 296   // expression or an error.
 297   Expression*
 298   verify_not_sink(Expression*);
 299
 300   // Return the statement associated with a label in a Bc_stack, or
 301   // NULL.
 302   Statement*
 303   find_bc_statement(const Bc_stack*, const std::string&) const;
 304
 305   // Mark a variable as used.
 306   void
 307   mark_var_used(Named_object*);
 308
 309   // The lexer output we are parsing.
 310   Lex* lex_;
 311   // The current token.
 312   Token token_;
 313   // A token pushed back on the input stream.
 314   Token unget_token_;
 315   // Whether unget_token_ is valid.
 316   bool unget_token_valid_;
 317   // Whether the function we are parsing had errors in the signature.
 318   bool is_erroneous_function_;
 319   // The code we are generating.
 320   Gogo* gogo_;
 321   // A stack of statements for which break may be used.
 322   Bc_stack* break_stack_;
 323   // A stack of statements for which continue may be used.
 324   Bc_stack* continue_stack_;
 325   // The current iota value.
 326   int iota_;
 327   // References from the local function to variables defined in
 328   // enclosing functions.
 329   Enclosing_vars enclosing_vars_;
 330   // Map from type switch variables to real variables.
 331   Type_switch_vars type_switch_vars_;
 332 };
 333
 334
 335 #endif // !defined(GO_PARSE_H)