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 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_CHANOP,
  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     source_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   // Peek at the current token from the lexer.
 136   const Token*
 137   peek_token();
 138
 139   // Consume the current token, return the next one.
 140   const Token*
 141   advance_token();
 142
 143   // Push a token back on the input stream.
 144   void
 145   unget_token(const Token&);
 146
 147   // The location of the current token.
 148   source_location
 149   location();
 150
 151   // For break and continue we keep a stack of statements with
 152   // associated labels (if any).  The top of the stack is used for a
 153   // break or continue statement with no label.
 154   typedef std::vector<std::pair<Statement*, const Label*> > Bc_stack;
 155
 156   // Parser nonterminals.
 157   void identifier_list(Typed_identifier_list*);
 158   Expression_list* expression_list(Expression*, bool may_be_sink);
 159   bool qualified_ident(std::string*, Named_object**);
 160   Type* type();
 161   bool type_may_start_here();
 162   Type* type_name(bool issue_error);
 163   Type* array_type(bool may_use_ellipsis);
 164   Type* map_type();
 165   Type* struct_type();
 166   void field_decl(Struct_field_list*);
 167   Type* pointer_type();
 168   Type* channel_type();
 169   Function_type* signature(Typed_identifier*, source_location);
 170   bool parameters(Typed_identifier_list**, bool* is_varargs);
 171   Typed_identifier_list* parameter_list(bool* is_varargs);
 172   void parameter_decl(bool, Typed_identifier_list*, bool*, bool*);
 173   bool result(Typed_identifier_list**);
 174   source_location block();
 175   Type* interface_type();
 176   void method_spec(Typed_identifier_list*);
 177   void declaration();
 178   bool declaration_may_start_here();
 179   void decl(void (Parse::*)(void*), void*);
 180   void list(void (Parse::*)(void*), void*, bool);
 181   void const_decl();
 182   void const_spec(Type**, Expression_list**);
 183   void type_decl();
 184   void type_spec(void*);
 185   void var_decl();
 186   void var_spec(void*);
 187   void init_vars(const Typed_identifier_list*, Type*, Expression_list*,
 188                  bool is_coloneq, source_location);
 189   bool init_vars_from_call(const Typed_identifier_list*, Type*, Expression*,
 190                            bool is_coloneq, source_location);
 191   bool init_vars_from_map(const Typed_identifier_list*, Type*, Expression*,
 192                           bool is_coloneq, source_location);
 193   bool init_vars_from_receive(const Typed_identifier_list*, Type*,
 194                               Expression*, bool is_coloneq, source_location);
 195   bool init_vars_from_type_guard(const Typed_identifier_list*, Type*,
 196                                  Expression*, bool is_coloneq,
 197                                  source_location);
 198   Named_object* init_var(const Typed_identifier&, Type*, Expression*,
 199                          bool is_coloneq, bool type_from_init, bool* is_new);
 200   Named_object* create_dummy_global(Type*, Expression*, source_location);
 201   void simple_var_decl_or_assignment(const std::string&, source_location,
 202                                      Range_clause*, Type_switch*);
 203   void function_decl();
 204   Typed_identifier* receiver();
 205   Expression* operand(bool may_be_sink);
 206   Expression* enclosing_var_reference(Named_object*, Named_object*,
 207                                       source_location);
 208   Expression* composite_lit(Type*, int depth, source_location);
 209   Expression* function_lit();
 210   Expression* create_closure(Named_object* function, Enclosing_vars*,
 211                              source_location);
 212   Expression* primary_expr(bool may_be_sink, bool may_be_composite_lit,
 213                            bool* is_type_switch);
 214   Expression* selector(Expression*, bool* is_type_switch);
 215   Expression* index(Expression*);
 216   Expression* call(Expression*);
 217   Expression* expression(Precedence, bool may_be_sink,
 218                          bool may_be_composite_lit, bool* is_type_switch);
 219   bool expression_may_start_here();
 220   Expression* unary_expr(bool may_be_sink, bool may_be_composite_lit,
 221                          bool* is_type_switch);
 222   Expression* qualified_expr(Expression*, source_location);
 223   Expression* id_to_expression(const std::string&, source_location);
 224   void statement(const Label*);
 225   bool statement_may_start_here();
 226   void labeled_stmt(const std::string&, source_location);
 227   Expression* simple_stat(bool, bool, Range_clause*, Type_switch*);
 228   bool simple_stat_may_start_here();
 229   void statement_list();
 230   bool statement_list_may_start_here();
 231   void expression_stat(Expression*);
 232   void inc_dec_stat(Expression*);
 233   void assignment(Expression*, Range_clause*);
 234   void tuple_assignment(Expression_list*, Range_clause*);
 235   void send();
 236   void go_or_defer_stat();
 237   void return_stat();
 238   void if_stat();
 239   void switch_stat(const Label*);
 240   Statement* expr_switch_body(const Label*, Expression*, source_location);
 241   void expr_case_clause(Case_clauses*, bool* saw_default);
 242   Expression_list* expr_switch_case(bool*);
 243   Statement* type_switch_body(const Label*, const Type_switch&,
 244                               source_location);
 245   void type_case_clause(Named_object*, Type_case_clauses*, bool* saw_default);
 246   void type_switch_case(std::vector<Type*>*, bool*);
 247   void select_stat(const Label*);
 248   void comm_clause(Select_clauses*, bool* saw_default);
 249   bool comm_case(bool*, Expression**, Expression**, std::string*, bool*);
 250   bool send_or_recv_expr(bool*, Expression**, Expression**, std::string*);
 251   void for_stat(const Label*);
 252   void for_clause(Expression**, Block**);
 253   void range_clause_decl(const Typed_identifier_list*, Range_clause*);
 254   void range_clause_expr(const Expression_list*, Range_clause*);
 255   void push_break_statement(Statement*, const Label*);
 256   void push_continue_statement(Statement*, const Label*);
 257   void pop_break_statement();
 258   void pop_continue_statement();
 259   Statement* find_bc_statement(const Bc_stack*, const std::string&);
 260   void break_stat();
 261   void continue_stat();
 262   void goto_stat();
 263   void package_clause();
 264   void import_decl();
 265   void import_spec(void*);
 266
 267   void reset_iota();
 268   int iota_value();
 269   void increment_iota();
 270
 271   // Skip past an error looking for a semicolon or OP.  Return true if
 272   // all is well, false if we found EOF.
 273   bool
 274   skip_past_error(Operator op);
 275
 276   // Verify that an expression is not a sink, and return either the
 277   // expression or an error.
 278   Expression*
 279   verify_not_sink(Expression*);
 280
 281   // Return the statement associated with a label in a Bc_stack, or
 282   // NULL.
 283   Statement*
 284   find_bc_statement(const Bc_stack*, const std::string&) const;
 285
 286   // The lexer output we are parsing.
 287   Lex* lex_;
 288   // The current token.
 289   Token token_;
 290   // A token pushed back on the input stream.
 291   Token unget_token_;
 292   // Whether unget_token_ is valid.
 293   bool unget_token_valid_;
 294   // The code we are generating.
 295   Gogo* gogo_;
 296   // A stack of statements for which break may be used.
 297   Bc_stack* break_stack_;
 298   // A stack of statements for which continue may be used.
 299   Bc_stack* continue_stack_;
 300   // The current iota value.
 301   int iota_;
 302   // References from the local function to variables defined in
 303   // enclosing functions.
 304   Enclosing_vars enclosing_vars_;
 305 };
 306
 307
 308 #endif // !defined(GO_PARSE_H)