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 Lex;
  11 class Gogo;
  12 class Named_object;
  13 class Type;
  14 class Typed_identifier;
  15 class Typed_identifier_list;
  16 class Channel_type;
  17 class Function_type;
  18 class Block;
  19 class Expression;
  20 class Expression_list;
  21 class Struct_field_list;
  22 class Case_clauses;
  23 class Type_case_clauses;
  24 class Select_clauses;
  25 class Statement;
  26 class Label;
  27
  28 // Parse the program.
  29
  30 class Parse
  31 {
  32  public:
  33   Parse(Lex*, Gogo*);
  34
  35   // Parse a program.
  36   void
  37   program();
  38
  39  private:
  40   // Precedence values.
  41   enum Precedence
  42   {
  43     PRECEDENCE_INVALID = -1,
  44     PRECEDENCE_NORMAL = 0,
  45     PRECEDENCE_OROR,
  46     PRECEDENCE_ANDAND,
  47     PRECEDENCE_RELOP,
  48     PRECEDENCE_ADDOP,
  49     PRECEDENCE_MULOP
  50   };
  51
  52   // We use this when parsing the range clause of a for statement.
  53   struct Range_clause
  54   {
  55     // Set to true if we found a range clause.
  56     bool found;
  57     // The index expression.
  58     Expression* index;
  59     // The value expression.
  60     Expression* value;
  61     // The range expression.
  62     Expression* range;
  63
  64     Range_clause()
  65       : found(false), index(NULL), value(NULL), range(NULL)
  66     { }
  67   };
  68
  69   // We use this when parsing the statement at the start of a switch,
  70   // in order to recognize type switches.
  71   struct Type_switch
  72   {
  73     // Set to true if we find a type switch.
  74     bool found;
  75     // The variable name.
  76     std::string name;
  77     // The location of the variable.
  78     Location location;
  79     // The expression.
  80     Expression* expr;
  81
  82     Type_switch()
  83         : found(false), name(), location(Linemap::unknown_location()),
  84           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&) const;
 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   // Parser nonterminals.
 160   void identifier_list(Typed_identifier_list*);
 161   Expression_list* expression_list(Expression*, bool may_be_sink,
 162                                    bool may_be_composite_lit);
 163   bool qualified_ident(std::string*, Named_object**);
 164   Type* type();
 165   bool type_may_start_here();
 166   Type* type_name(bool issue_error);
 167   Type* array_type(bool may_use_ellipsis);
 168   Type* map_type();
 169   Type* struct_type();
 170   void field_decl(Struct_field_list*);
 171   Type* pointer_type();
 172   Type* channel_type();
 173   void check_signature_names(const Typed_identifier_list*, Names*);
 174   Function_type* signature(Typed_identifier*, Location);
 175   bool parameters(Typed_identifier_list**, bool* is_varargs);
 176   Typed_identifier_list* parameter_list(bool* is_varargs);
 177   void parameter_decl(bool, Typed_identifier_list*, bool*, bool*, bool*);
 178   bool result(Typed_identifier_list**);
 179   Location block();
 180   Type* interface_type(bool record);
 181   void method_spec(Typed_identifier_list*);
 182   void declaration();
 183   bool declaration_may_start_here();
 184   void decl(void (Parse::*)());
 185   void list(void (Parse::*)(), bool);
 186   void const_decl();
 187   void const_spec(int, Type**, Expression_list**);
 188   void update_references(Expression**);
 189   void type_decl();
 190   void type_spec();
 191   void var_decl();
 192   void var_spec();
 193   void init_vars(const Typed_identifier_list*, Type*, Expression_list*,
 194                  bool is_coloneq, std::vector<std::string>*, Location);
 195   bool init_vars_from_call(const Typed_identifier_list*, Type*, Expression*,
 196                            bool is_coloneq, Location);
 197   bool init_vars_from_map(const Typed_identifier_list*, Type*, Expression*,
 198                           bool is_coloneq, Location);
 199   bool init_vars_from_receive(const Typed_identifier_list*, Type*,
 200                               Expression*, bool is_coloneq, Location);
 201   bool init_vars_from_type_guard(const Typed_identifier_list*, Type*,
 202                                  Expression*, bool is_coloneq,
 203                                  Location);
 204   Named_object* init_var(const Typed_identifier&, Type*, Expression*,
 205                          bool is_coloneq, bool type_from_init, bool* is_new,
 206                          Expression_list* vars, Expression_list* vals);
 207   Named_object* create_dummy_global(Type*, Expression*, Location);
 208   void finish_init_vars(Expression_list* vars, Expression_list* vals,
 209                         Location);
 210   void simple_var_decl_or_assignment(const std::string&, Location,
 211                                      bool may_be_composite_lit,
 212                                      Range_clause*, Type_switch*);
 213   void function_decl();
 214   Typed_identifier* receiver();
 215   Expression* operand(bool may_be_sink, bool *is_parenthesized);
 216   Expression* enclosing_var_reference(Named_object*, Named_object*,
 217                                       bool may_be_sink, Location);
 218   Expression* composite_lit(Type*, int depth, Location);
 219   Expression* function_lit();
 220   Expression* create_closure(Named_object* function, Enclosing_vars*,
 221                              Location);
 222   Expression* primary_expr(bool may_be_sink, bool may_be_composite_lit,
 223                            bool* is_type_switch, bool* is_parenthesized);
 224   Expression* selector(Expression*, bool* is_type_switch);
 225   Expression* index(Expression*);
 226   Expression* call(Expression*);
 227   Expression* expression(Precedence, bool may_be_sink,
 228                          bool may_be_composite_lit, bool* is_type_switch,
 229                          bool *is_parenthesized);
 230   bool expression_may_start_here();
 231   Expression* unary_expr(bool may_be_sink, bool may_be_composite_lit,
 232                          bool* is_type_switch, bool* is_parenthesized);
 233   Type* reassociate_chan_direction(Channel_type*, Location);
 234   Expression* qualified_expr(Expression*, Location);
 235   Expression* id_to_expression(const std::string&, Location, bool, bool);
 236   void statement(Label*);
 237   bool statement_may_start_here();
 238   void labeled_stmt(const std::string&, Location);
 239   Expression* simple_stat(bool, bool*, Range_clause*, Type_switch*);
 240   bool simple_stat_may_start_here();
 241   void statement_list();
 242   bool statement_list_may_start_here();
 243   void expression_stat(Expression*);
 244   void send_stmt(Expression*, bool may_be_composite_lit);
 245   void inc_dec_stat(Expression*);
 246   void assignment(Expression*, bool may_be_composite_lit, Range_clause*);
 247   void tuple_assignment(Expression_list*, bool may_be_composite_lit,
 248                         Range_clause*);
 249   void send();
 250   void go_or_defer_stat();
 251   void return_stat();
 252   void if_stat();
 253   void switch_stat(Label*);
 254   Statement* expr_switch_body(Label*, Expression*, Location);
 255   void expr_case_clause(Case_clauses*, bool* saw_default);
 256   Expression_list* expr_switch_case(bool*);
 257   Statement* type_switch_body(Label*, const Type_switch&, Location);
 258   void type_case_clause(const std::string&, Expression*, Type_case_clauses*,
 259                         bool* saw_default, std::vector<Named_object*>*);
 260   void type_switch_case(std::vector<Type*>*, bool*);
 261   void select_stat(Label*);
 262   void comm_clause(Select_clauses*, bool* saw_default);
 263   bool comm_case(bool*, Expression**, Expression**, Expression**,
 264                  std::string*, std::string*, bool*);
 265   bool send_or_recv_stmt(bool*, Expression**, Expression**, Expression**,
 266                          std::string*, std::string*);
 267   void for_stat(Label*);
 268   void for_clause(Expression**, Block**);
 269   void range_clause_decl(const Typed_identifier_list*, Range_clause*);
 270   void range_clause_expr(const Expression_list*, Range_clause*);
 271   void push_break_statement(Statement*, Label*);
 272   void push_continue_statement(Statement*, Label*);
 273   void pop_break_statement();
 274   void pop_continue_statement();
 275   Statement* find_bc_statement(const Bc_stack*, const std::string&);
 276   void break_stat();
 277   void continue_stat();
 278   void goto_stat();
 279   void package_clause();
 280   void import_decl();
 281   void import_spec();
 282
 283   // Check for unused compiler directives.
 284   void check_directives();
 285
 286   // Skip past an error looking for a semicolon or OP.  Return true if
 287   // all is well, false if we found EOF.
 288   bool
 289   skip_past_error(Operator op);
 290
 291   // Verify that an expression is not a sink, and return either the
 292   // expression or an error.
 293   Expression*
 294   verify_not_sink(Expression*);
 295
 296   // Return the statement associated with a label in a Bc_stack, or
 297   // NULL.
 298   Statement*
 299   find_bc_statement(const Bc_stack*, const std::string&) const;
 300
 301   // Mark a variable as used.
 302   void
 303   mark_var_used(Named_object*);
 304
 305   // The lexer output we are parsing.
 306   Lex* lex_;
 307   // The current token.
 308   Token token_;
 309   // A token pushed back on the input stream.
 310   Token unget_token_;
 311   // Whether unget_token_ is valid.
 312   bool unget_token_valid_;
 313   // Whether the function we are parsing had errors in the signature.
 314   bool is_erroneous_function_;
 315   // The code we are generating.
 316   Gogo* gogo_;
 317   // A stack of statements for which break may be used.
 318   Bc_stack* break_stack_;
 319   // A stack of statements for which continue may be used.
 320   Bc_stack* continue_stack_;
 321   // References from the local function to variables defined in
 322   // enclosing functions.
 323   Enclosing_vars enclosing_vars_;
 324 };
 325
 326
 327 #endif // !defined(GO_PARSE_H)