X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/8a4ec3595b706180f53458607cd64cca07af24cb..c4e686a1abd817b4d4da5bdd5b3a5540566fd4a0:/data/lalr1.cc?ds=sidebyside diff --git a/data/lalr1.cc b/data/lalr1.cc index 2c38cdf3..3773257c 100644 --- a/data/lalr1.cc +++ b/data/lalr1.cc @@ -149,10 +149,11 @@ b4_variant_if([m4_include(b4_pkgdatadir/[variant.hh])]) m4_define([b4_shared_declarations], [b4_percent_code_get([[requires]])[ ]b4_parse_assert_if([# include ])[ -# include +# include // std::abort # include # include -# include ]b4_defines_if([[ +# include +# include ]b4_defines_if([[ # include "stack.hh" ]b4_bison_locations_if([[# include "location.hh"]])])[ ]b4_variant_if([b4_variant_includes])[ @@ -214,9 +215,9 @@ b4_location_define])])[ /// Generate an error message. /// \param yystate the state where the error occurred. - /// \param yytoken the lookahead token type, or yyempty_. + /// \param yyla the lookahead token. virtual std::string yysyntax_error_ (state_type yystate, - symbol_number_type yytoken) const; + const symbol_type& yyla) const; /// Compute post-reduction state. /// \param yystate the current state @@ -288,15 +289,18 @@ b4_location_define])])[ /// Copy constructor. by_state (const by_state& other); + /// Record that this symbol is empty. + void clear (); + /// Steal the symbol type from \a that. void move (by_state& that); /// The (internal) type number (corresponding to \a state). - /// \a empty when empty. + /// \a empty_symbol when empty. symbol_number_type type_get () const; /// The state number used to denote an empty symbol. - enum { empty = 0 }; + enum { empty_state = -1 }; /// The state. /// \a empty when empty. @@ -346,7 +350,6 @@ b4_location_define])])[ yyeof_ = 0, yylast_ = ]b4_last[, ///< Last index in yytable_. yynnts_ = ]b4_nterms_number[, ///< Number of nonterminal symbols. - yyempty_ = -2, yyfinal_ = ]b4_final_state_number[, ///< Termination state number. yyterror_ = 1, yyerrcode_ = 256, @@ -466,7 +469,7 @@ m4_if(b4_prefix, [yy], [], #endif // !]b4_api_PREFIX[DEBUG #define yyerrok (yyerrstatus_ = 0) -#define yyclearin (yyempty = true) +#define yyclearin (yyla.clear ()) #define YYACCEPT goto yyacceptlab #define YYABORT goto yyabortlab @@ -535,7 +538,7 @@ m4_if(b4_prefix, [yy], [], // by_state. inline ]b4_parser_class_name[::by_state::by_state () - : state (empty) + : state (empty_state) {} inline @@ -543,12 +546,19 @@ m4_if(b4_prefix, [yy], [], : state (other.state) {} + inline + void + ]b4_parser_class_name[::by_state::clear () + { + state = empty_state; + } + inline void ]b4_parser_class_name[::by_state::move (by_state& that) { state = that.state; - that.state = empty; + that.clear (); } inline @@ -560,7 +570,10 @@ m4_if(b4_prefix, [yy], [], ]b4_parser_class_name[::symbol_number_type ]b4_parser_class_name[::by_state::type_get () const { - return state == empty ? 0 : yystos_[state]; + if (state == empty_state) + return empty_symbol; + else + return yystos_[state]; } inline @@ -576,7 +589,7 @@ m4_if(b4_prefix, [yy], [], [value], [move], [that.value])], [[value = that.value;]])[ // that is emptied. - that.type = empty; + that.type = empty_symbol; } inline @@ -613,6 +626,10 @@ m4_if(b4_prefix, [yy], [], std::ostream& yyoutput = yyo; YYUSE (yyoutput); symbol_number_type yytype = yysym.type_get (); + // Avoid a (spurious) G++ 4.8 warning about "array subscript is + // below array bounds". + if (yysym.empty ()) + std::abort (); yyo << (yytype < yyntokens_ ? "token" : "nterm") << ' ' << yytname_[yytype] << " ("]b4_locations_if([ << yysym.location << ": "])[; @@ -706,9 +723,6 @@ m4_if(b4_prefix, [yy], [], int yynerrs_ = 0; int yyerrstatus_ = 0; - /// Whether yyla contains a lookahead. - bool yyempty = true; - /// The lookahead symbol. symbol_type yyla;]b4_locations_if([[ @@ -756,7 +770,7 @@ b4_dollar_popdef])[]dnl goto yydefault; // Read a lookahead token. - if (yyempty) + if (yyla.empty ()) { YYCDEBUG << "Reading a token: "; try @@ -770,7 +784,6 @@ b4_dollar_popdef])[]dnl error (yyexc); goto yyerrlab1; } - yyempty = false; } YY_SYMBOL_PRINT ("Next token is", yyla); @@ -790,9 +803,6 @@ b4_dollar_popdef])[]dnl goto yyreduce; } - // Discard the token being shifted. - yyempty = true; - // Count tokens shifted since error; after three, turn off error status. if (yyerrstatus_) --yyerrstatus_; @@ -875,8 +885,7 @@ b4_dollar_popdef])[]dnl { ++yynerrs_; error (]b4_join(b4_locations_if([yyla.location]), - [[yysyntax_error_ (yystack_[0].state, - yyempty ? yyempty_ : yyla.type_get ())]])[); + [[yysyntax_error_ (yystack_[0].state, yyla)]])[); } ]b4_locations_if([[ @@ -889,10 +898,10 @@ b4_dollar_popdef])[]dnl // Return failure if at end of input. if (yyla.type_get () == yyeof_) YYABORT; - else if (!yyempty) + else if (!yyla.empty ()) { yy_destroy_ ("Error: discarding", yyla); - yyempty = true; + yyla.clear (); } } @@ -968,7 +977,7 @@ b4_dollar_popdef])[]dnl goto yyreturn; yyreturn: - if (!yyempty) + if (!yyla.empty ()) yy_destroy_ ("Cleanup: discarding lookahead", yyla); /* Do not reclaim the symbols of the rule whose action triggered @@ -988,7 +997,7 @@ b4_dollar_popdef])[]dnl << std::endl; // Do not try to display the values of the reclaimed symbols, // as their printer might throw an exception. - if (!yyempty) + if (!yyla.empty ()) yy_destroy_ (YY_NULLPTR, yyla); while (1 < yystack_.size ()) @@ -1010,8 +1019,8 @@ b4_dollar_popdef])[]dnl // Generate an error message. std::string ]b4_parser_class_name[::yysyntax_error_ (]dnl -b4_error_verbose_if([state_type yystate, symbol_number_type yytoken], - [state_type, symbol_number_type])[) const +b4_error_verbose_if([state_type yystate, const symbol_type& yyla], + [state_type, const symbol_type&])[) const {]b4_error_verbose_if([[ // Number of reported tokens (one for the "unexpected", one per // "expected"). @@ -1026,7 +1035,7 @@ b4_error_verbose_if([state_type yystate, symbol_number_type yytoken], the only way this function was invoked is if the default action is an error action. In that case, don't check for expected tokens because there are none. - - The only way there can be no lookahead present (in yytoken) is + - The only way there can be no lookahead present (in yyla) is if this state is a consistent state with a default action. Thus, detecting the absence of a lookahead is sufficient to determine that there is no unexpected or expected token to @@ -1046,8 +1055,9 @@ b4_error_verbose_if([state_type yystate, symbol_number_type yytoken], token that will not be accepted due to an error action in a later state. */ - if (yytoken != yyempty_) + if (!yyla.empty ()) { + int yytoken = yyla.type_get (); yyarg[yycount++] = yytname_[yytoken]; int yyn = yypact_[yystate]; if (!yy_pact_value_is_default_ (yyn))