mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-04 09:09:56 +00:00
9f36c7f497
In case you're wondering, the gcc-2.7.2.1 import uses this to generate code. The size of the generated code is bigger than the entire bison release, making this a saving. The bison doc is pretty good apparently.
126 lines
4.3 KiB
C
126 lines
4.3 KiB
C
/* Data definitions for internal representation of bison's input,
|
|
Copyright (C) 1984, 1986, 1989, 1992 Free Software Foundation, Inc.
|
|
|
|
This file is part of Bison, the GNU Compiler Compiler.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
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. */
|
|
|
|
|
|
/* representation of the grammar rules:
|
|
|
|
ntokens is the number of tokens, and nvars is the number of variables
|
|
(nonterminals). nsyms is the total number, ntokens + nvars.
|
|
|
|
(the true number of token values assigned is ntokens
|
|
reduced by one for each alias declaration)
|
|
|
|
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 rules receive rule numbers 1 to nrules in the order they are written.
|
|
Actions and guards are accessed via the rule number.
|
|
|
|
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.
|
|
|
|
If rlhs[R] is -1, the rule has been thrown out by reduce.c
|
|
and should be ignored.
|
|
|
|
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 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.
|
|
|
|
Item numbers are used in the finite state machine to represent
|
|
places that parsing can get to.
|
|
|
|
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).
|
|
|
|
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 rassoc and sassoc. */
|
|
|
|
|
|
#define ISTOKEN(s) ((s) < ntokens)
|
|
#define ISVAR(s) ((s) >= 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 */
|
|
|
|
extern int start_symbol;
|
|
|
|
|
|
/* associativity values in elements of rassoc, sassoc. */
|
|
|
|
#define RIGHT_ASSOC 1
|
|
#define LEFT_ASSOC 2
|
|
#define NON_ASSOC 3
|
|
|
|
/* 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...")
|
|
*/
|
|
|
|
extern short *token_translations;
|
|
extern int 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. */
|
|
|
|
extern int pure_parser;
|
|
|
|
/* error_token_number is the token number of the error token. */
|
|
|
|
extern int error_token_number;
|