X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/9f690211058a7f67031248302f1996d96bba2087..3583d96b77e260c83bacd40937de727cd4b9ff18:/src/gram.h diff --git a/src/gram.h b/src/gram.h index 080ce0d9..ffc9ca81 100644 --- a/src/gram.h +++ b/src/gram.h @@ -1,125 +1,275 @@ -/* Data definitions for internal representation of bison's input, - Copyright (C) 1984, 1986, 1989, 1992 Free Software Foundation, Inc. +/* Data definitions for internal representation of Bison's input. -This file is part of Bison, the GNU Compiler Compiler. + Copyright (C) 1984, 1986, 1989, 1992, 2001, 2002, 2003, 2004, 2005, 2006 + 2007, 2008 Free Software Foundation, Inc. -Bison is free software; you can redistribute it and/or modify -it under the terms of the GNU General Public License as published by -the Free Software Foundation; either version 2, or (at your option) -any later version. + This file is part of Bison, the GNU Compiler Compiler. -Bison is distributed in the hope that it will be useful, -but WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -GNU General Public License for more details. + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. -You should have received a copy of the GNU General Public License -along with Bison; see the file COPYING. If not, write to -the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ -/* representation of the grammar rules: +#ifndef GRAM_H_ +# define GRAM_H_ -ntokens is the number of tokens, and nvars is the number of variables -(nonterminals). nsyms is the total number, ntokens + nvars. +/* Representation of the grammar rules: - (the true number of token values assigned is ntokens - reduced by one for each alias declaration) + NTOKENS is the number of tokens, and NVARS is the number of + variables (nonterminals). NSYMS is the total number, ntokens + + nvars. -Each symbol (either token or variable) receives a symbol number. -Numbers 0 to ntokens-1 are for tokens, and ntokens to nsyms-1 are for -variables. Symbol number zero is the end-of-input token. This token -is counted in ntokens. + Each symbol (either token or variable) receives a symbol number. + Numbers 0 to NTOKENS - 1 are for tokens, and NTOKENS to NSYMS - 1 + are for variables. Symbol number zero is the end-of-input token. + This token is counted in ntokens. The true number of token values + assigned is NTOKENS reduced by one for each alias declaration. -The rules receive rule numbers 1 to nrules in the order they are written. -Actions and guards are accessed via the rule number. + The rules receive rule numbers 1 to NRULES in the order they are + written. More precisely Bison augments the grammar with the + initial rule, `$accept: START-SYMBOL $end', which is numbered 1, + all the user rules are 2, 3 etc. Each time a rule number is + presented to the user, we subtract 1, so *displayed* rule numbers + are 0, 1, 2... -The rules themselves are described by three arrays: rrhs, rlhs and -ritem. rlhs[R] is the symbol number of the left hand side of rule R. -The right hand side is stored as symbol numbers in a portion of -ritem. rrhs[R] contains the index in ritem of the beginning of the -portion for rule R. + Internally, we cannot use the number 0 for a rule because for + instance RITEM stores both symbol (the RHS) and rule numbers: the + symbols are shorts >= 0, and rule number are stored negative. + Therefore 0 cannot be used, since it would be both the rule number + 0, and the token $end). -If rlhs[R] is -1, the rule has been thrown out by reduce.c -and should be ignored. + Actions are accessed via the rule number. -The length of the portion is one greater - than the number of symbols in the rule's right hand side. -The last element in the portion contains minus R, which -identifies it as the end of a portion and says which rule it is for. + The rules themselves are described by several arrays: amongst which + RITEM, and RULES. -The portions of ritem come in order of increasing rule number and are -followed by an element which is zero to mark the end. nitems is the -total length of ritem, not counting the final zero. Each element of -ritem is called an "item" and its index in ritem is an item number. + RULES is an array of rules, whose members are: -Item numbers are used in the finite state machine to represent -places that parsing can get to. + RULES[R].lhs -- the symbol of the left hand side of rule R. -Precedence levels are recorded in the vectors sprec and rprec. -sprec records the precedence level of each symbol, -rprec the precedence level of each rule. -rprecsym is the symbol-number of the symbol in %prec for this rule (if any). + RULES[R].rhs -- the index in RITEM of the beginning of the portion + for rule R. -Precedence levels are assigned in increasing order starting with 1 so -that numerically higher precedence values mean tighter binding as they -ought to. Zero as a symbol or rule's precedence means none is -assigned. + RULES[R].prec -- the symbol providing the precedence level of R. -Associativities are recorded similarly in rassoc and sassoc. */ + RULES[R].precsym -- the symbol attached (via %prec) to give its + precedence to R. Of course, if set, it is equal to `prec', but we + need to distinguish one from the other when reducing: a symbol used + in a %prec is not useless. + RULES[R].assoc -- the associativity of R. -#define ISTOKEN(s) ((s) < ntokens) -#define ISVAR(s) ((s) >= ntokens) + RULES[R].dprec -- the dynamic precedence level of R (for GLR + parsing). + RULES[R].merger -- index of merging function for R (for GLR + parsing). + + RULES[R].line -- the line where R was defined. + + RULES[R].useful -- true iff the rule is used (i.e., false if thrown + away by reduce). + + The right hand side is stored as symbol numbers in a portion of + RITEM. + + The length of the portion is one greater than the number of symbols + in the rule's right hand side. The last element in the portion + contains minus R, which identifies it as the end of a portion and + says which rule it is for. + + The portions of RITEM come in order of increasing rule number. + NRITEMS is the total length of RITEM. Each element of RITEM is + called an "item" and its index in RITEM is an item number. + + Item numbers are used in the finite state machine to represent + places that parsing can get to. + + SYMBOLS[I]->prec records the precedence level of each symbol. + + Precedence levels are assigned in increasing order starting with 1 + so that numerically higher precedence values mean tighter binding + as they ought to. Zero as a symbol or rule's precedence means none + is assigned. + + Associativities are recorded similarly in SYMBOLS[I]->assoc. */ + +# include "location.h" +# include "symtab.h" + +# define ISTOKEN(i) ((i) < ntokens) +# define ISVAR(i) ((i) >= ntokens) -extern int nitems; -extern int nrules; extern int nsyms; extern int ntokens; extern int nvars; -extern short *ritem; -extern short *rlhs; -extern short *rrhs; -extern short *rprec; -extern short *rprecsym; -extern short *sprec; -extern short *rassoc; -extern short *sassoc; -extern short *rline; /* Source line number of each rule */ +typedef int item_number; +#define ITEM_NUMBER_MAX INT_MAX +extern item_number *ritem; +extern unsigned int nritems; + +/* There is weird relationship between OT1H item_number and OTOH + symbol_number and rule_number: we store the latter in + item_number. symbol_number values are stored as-is, while + the negation of (rule_number + 1) is stored. + + Therefore, a symbol_number must be a valid item_number, and we + sometimes have to perform the converse transformation. */ + +static inline item_number +symbol_number_as_item_number (symbol_number sym) +{ + return sym; +} + +static inline symbol_number +item_number_as_symbol_number (item_number i) +{ + return i; +} + +static inline bool +item_number_is_symbol_number (item_number i) +{ + return i >= 0; +} + +/* Rule numbers. */ +typedef int rule_number; +#define RULE_NUMBER_MAX INT_MAX +extern rule_number nrules; + +static inline item_number +rule_number_as_item_number (rule_number r) +{ + return -1 - r; +} + +static inline rule_number +item_number_as_rule_number (item_number i) +{ + return -1 - i; +} + +static inline bool +item_number_is_rule_number (item_number i) +{ + return i < 0; +} + +/*--------. +| Rules. | +`--------*/ + +typedef struct +{ + /* The number of the rule in the source. It is usually the index in + RULES too, except if there are useless rules. */ + rule_number user_number; + + /* The index in RULES. Usually the rule number in the source, + except if some rules are useless. */ + rule_number number; -extern int start_symbol; + symbol *lhs; + item_number *rhs; + /* This symbol provides both the associativity, and the precedence. */ + symbol *prec; -/* associativity values in elements of rassoc, sassoc. */ + int dprec; + int merger; -#define RIGHT_ASSOC 1 -#define LEFT_ASSOC 2 -#define NON_ASSOC 3 + /* This symbol was attached to the rule via %prec. */ + symbol *precsym; -/* token translation table: -indexed by a token number as returned by the user's yylex routine, -it yields the internal token number used by the parser and throughout bison. -If translations is zero, the translation table is not used because -the two kinds of token numbers are the same. -(It is noted in reader.c that "Nowadays translations is always set to 1...") -*/ + location location; + bool useful; -extern short *token_translations; -extern int translations; + const char *action; + location action_location; +} rule; + +extern rule *rules; + +/* A function that selects a rule. */ +typedef bool (*rule_filter) (rule *); + +/* Return true IFF the rule has a `number' smaller than NRULES. That is, it is + useful in the grammar. */ +bool rule_useful_in_grammar_p (rule *r); + +/* Return true IFF the rule has a `number' higher than NRULES. That is, it is + useless in the grammar. */ +bool rule_useless_in_grammar_p (rule *r); + +/* Return true IFF the rule is not flagged as useful but is useful in the + grammar. In other words, it was discarded because of conflicts. */ +bool rule_useless_in_parser_p (rule *r); + +/* Print this rule's number and lhs on OUT. If a PREVIOUS_LHS was + already displayed (by a previous call for another rule), avoid + useless repetitions. */ +void rule_lhs_print (rule *r, symbol *previous_lhs, FILE *out); +void rule_lhs_print_xml (rule *r, FILE *out, int level); + +/* Return the length of the RHS. */ +size_t rule_rhs_length (rule *r); + +/* Print this rule's RHS on OUT. */ +void rule_rhs_print (rule *r, FILE *out); + +/* Print this rule on OUT. */ +void rule_print (rule *r, FILE *out); + + + + +/* Table of the symbols, indexed by the symbol number. */ +extern symbol **symbols; + +/* TOKEN_TRANSLATION -- a table indexed by a token number as returned + by the user's yylex routine, it yields the internal token number + used by the parser and throughout bison. */ +extern symbol_number *token_translations; extern int max_user_token_number; -/* semantic_parser is nonzero if the input file says to use the hairy parser -that provides for semantic error recovery. If it is zero, the yacc-compatible -simplified parser is used. */ -extern int semantic_parser; -/* pure_parser is nonzero if should generate a parser that is all pure and reentrant. */ +/* Dump RITEM for traces. */ +void ritem_print (FILE *out); + +/* Return the size of the longest rule RHS. */ +size_t ritem_longest_rhs (void); + +/* Print the grammar's rules that match FILTER on OUT under TITLE. */ +void grammar_rules_partial_print (FILE *out, const char *title, + rule_filter filter); + +/* Print the grammar's useful rules on OUT. */ +void grammar_rules_print (FILE *out); +/* Print all of the grammar's rules with a "usefulness" attribute. */ +void grammar_rules_print_xml (FILE *out, int level); + +/* Dump the grammar. */ +void grammar_dump (FILE *out, const char *title); -extern int pure_parser; +/* Report on STDERR the rules that are not flagged USEFUL, using the + MESSAGE (which can be `rule useless in grammar' when invoked after grammar + reduction, or `rule useless in parser due to conflicts' after conflicts + were taken into account). */ +void grammar_rules_useless_report (const char *message); -/* error_token_number is the token number of the error token. */ +/* Free the packed grammar. */ +void grammar_free (void); -extern int error_token_number; +#endif /* !GRAM_H_ */