1 | /* Compute lookahead criteria for bison, |
2 | |
3 | Copyright (C) 1984, 1986, 1989, 2000, 2002, 2004, 2006-2007, |
4 | 2009-2015, 2018-2019 Free Software Foundation, Inc. |
5 | |
6 | This file is part of Bison, the GNU Compiler Compiler. |
7 | |
8 | This program is free software: you can redistribute it and/or modify |
9 | it under the terms of the GNU General Public License as published by |
10 | the Free Software Foundation, either version 3 of the License, or |
11 | (at your option) any later version. |
12 | |
13 | This program is distributed in the hope that it will be useful, |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
16 | GNU General Public License for more details. |
17 | |
18 | You should have received a copy of the GNU General Public License |
19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
20 | |
21 | #ifndef LALR_H_ |
22 | # define LALR_H_ |
23 | |
24 | # include <bitset.h> |
25 | # include <bitsetv.h> |
26 | |
27 | /* Import the definition of RULE_T. */ |
28 | # include "gram.h" |
29 | |
30 | /* Import the definition of CORE, TRANSITIONS and REDUCTIONS. */ |
31 | # include "state.h" |
32 | |
33 | |
34 | /** Build the LALR(1) automaton. |
35 | |
36 | Find which rules need lookahead in each state, and which lookahead |
37 | tokens they accept. |
38 | |
39 | Also builds: |
40 | - #goto_map |
41 | - #from_state |
42 | - #to_state |
43 | - #goto_follows |
44 | */ |
45 | void lalr (void); |
46 | |
47 | /** |
48 | * Set #nLA and allocate all reduction lookahead sets. Normally invoked by |
49 | * #lalr. |
50 | */ |
51 | void initialize_LA (void); |
52 | |
53 | /** |
54 | * Build only: |
55 | * - #goto_map |
56 | * - #from_state |
57 | * - #to_state |
58 | * Normally invoked by #lalr. |
59 | */ |
60 | void set_goto_map (void); |
61 | |
62 | /** |
63 | * Update state numbers recorded in #goto_map, #from_state, and #to_state such |
64 | * that: |
65 | * - \c nstates_old is the old number of states. |
66 | * - Where \c i is the old state number, <tt>old_to_new[i]</tt> is either: |
67 | * - \c nstates_old if state \c i is removed because it is unreachable. |
68 | * Thus, remove all goto entries involving this state. |
69 | * - The new state number. |
70 | */ |
71 | void lalr_update_state_numbers (state_number old_to_new[], |
72 | state_number nstates_old); |
73 | |
74 | |
75 | /** Release the information related to lookahead tokens. |
76 | |
77 | Can be performed once the action tables are computed. */ |
78 | void lalr_free (void); |
79 | |
80 | typedef size_t goto_number; |
81 | # define GOTO_NUMBER_MAXIMUM ((goto_number) -1) |
82 | |
83 | /** Index into #from_state and #to_state. |
84 | |
85 | All the transitions that accept a particular variable are grouped |
86 | together in FROM_STATE and TO_STATE, with indexes from GOTO_MAP[I - |
87 | NTOKENS] to GOTO_MAP[I - NTOKENS + 1] - 1 (including both). */ |
88 | extern goto_number *goto_map; |
89 | |
90 | /** The size of #from_state and #to_state. */ |
91 | extern goto_number ngotos; |
92 | |
93 | /** State number which a transition leads from. */ |
94 | extern state_number *from_state; |
95 | |
96 | /** State number it leads to. */ |
97 | extern state_number *to_state; |
98 | |
99 | /** The number of the goto from state SRC labeled with nterm SYM. */ |
100 | goto_number map_goto (state_number src, symbol_number sym); |
101 | |
102 | /* goto_follows[i] is the set of tokens following goto i. */ |
103 | extern bitsetv goto_follows; |
104 | |
105 | #endif /* !LALR_H_ */ |
106 | |