Guido van Rossum | f70e43a | 1991-02-19 12:39:46 +0000 | [diff] [blame] | 1 | /*********************************************************** |
| 2 | Copyright 1991 by Stichting Mathematisch Centrum, Amsterdam, The |
| 3 | Netherlands. |
| 4 | |
| 5 | All Rights Reserved |
| 6 | |
| 7 | Permission to use, copy, modify, and distribute this software and its |
| 8 | documentation for any purpose and without fee is hereby granted, |
| 9 | provided that the above copyright notice appear in all copies and that |
| 10 | both that copyright notice and this permission notice appear in |
| 11 | supporting documentation, and that the names of Stichting Mathematisch |
| 12 | Centrum or CWI not be used in advertising or publicity pertaining to |
| 13 | distribution of the software without specific, written prior permission. |
| 14 | |
| 15 | STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO |
| 16 | THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND |
| 17 | FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE |
| 18 | FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| 19 | WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| 20 | ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT |
| 21 | OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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| 23 | ******************************************************************/ |
| 24 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 25 | /* Parser accelerator module */ |
| 26 | |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 27 | /* The parser as originally conceived had disappointing performance. |
| 28 | This module does some precomputation that speeds up the selection |
| 29 | of a DFA based upon a token, turning a search through an array |
| 30 | into a simple indexing operation. The parser now cannot work |
| 31 | without the accelerators installed. Note that the accelerators |
| 32 | are installed dynamically when the parser is initialized, they |
| 33 | are not part of the static data structure written on graminit.[ch] |
| 34 | by the parser generator. */ |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 35 | |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 36 | #include "pgenheaders.h" |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 37 | #include "grammar.h" |
| 38 | #include "token.h" |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 39 | #include "parser.h" |
| 40 | |
| 41 | /* Forward references */ |
| 42 | static void fixdfa PROTO((grammar *, dfa *)); |
| 43 | static void fixstate PROTO((grammar *, dfa *, state *)); |
| 44 | |
| 45 | void |
| 46 | addaccelerators(g) |
| 47 | grammar *g; |
| 48 | { |
| 49 | dfa *d; |
| 50 | int i; |
| 51 | #ifdef DEBUG |
| 52 | printf("Adding parser accellerators ...\n"); |
| 53 | #endif |
| 54 | d = g->g_dfa; |
| 55 | for (i = g->g_ndfas; --i >= 0; d++) |
| 56 | fixdfa(g, d); |
| 57 | g->g_accel = 1; |
| 58 | #ifdef DEBUG |
| 59 | printf("Done.\n"); |
| 60 | #endif |
| 61 | } |
| 62 | |
| 63 | static void |
| 64 | fixdfa(g, d) |
| 65 | grammar *g; |
| 66 | dfa *d; |
| 67 | { |
| 68 | state *s; |
| 69 | int j; |
| 70 | s = d->d_state; |
| 71 | for (j = 0; j < d->d_nstates; j++, s++) |
| 72 | fixstate(g, d, s); |
| 73 | } |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 74 | |
| 75 | static void |
| 76 | fixstate(g, d, s) |
| 77 | grammar *g; |
| 78 | dfa *d; |
| 79 | state *s; |
| 80 | { |
| 81 | arc *a; |
| 82 | int k; |
| 83 | int *accel; |
| 84 | int nl = g->g_ll.ll_nlabels; |
| 85 | s->s_accept = 0; |
| 86 | accel = NEW(int, nl); |
| 87 | for (k = 0; k < nl; k++) |
| 88 | accel[k] = -1; |
| 89 | a = s->s_arc; |
| 90 | for (k = s->s_narcs; --k >= 0; a++) { |
| 91 | int lbl = a->a_lbl; |
| 92 | label *l = &g->g_ll.ll_label[lbl]; |
| 93 | int type = l->lb_type; |
| 94 | if (a->a_arrow >= (1 << 7)) { |
| 95 | printf("XXX too many states!\n"); |
| 96 | continue; |
| 97 | } |
| 98 | if (ISNONTERMINAL(type)) { |
| 99 | dfa *d1 = finddfa(g, type); |
| 100 | int ibit; |
| 101 | if (type - NT_OFFSET >= (1 << 7)) { |
| 102 | printf("XXX too high nonterminal number!\n"); |
| 103 | continue; |
| 104 | } |
| 105 | for (ibit = 0; ibit < g->g_ll.ll_nlabels; ibit++) { |
| 106 | if (testbit(d1->d_first, ibit)) { |
Guido van Rossum | 7d8b509 | 1991-09-10 14:53:39 +0000 | [diff] [blame] | 107 | #ifdef applec |
| 108 | #define MPW_881_bug /* Undefine if bug below is fixed */ |
| 109 | #endif |
| 110 | #ifdef MPW_881_BUG |
| 111 | /* In 881 mode MPW 3.1 has a code |
| 112 | generation bug which seems to |
| 113 | set the upper bits; fix this by |
| 114 | explicitly masking them off */ |
| 115 | int temp; |
| 116 | #endif |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 117 | if (accel[ibit] != -1) |
| 118 | printf("XXX ambiguity!\n"); |
Guido van Rossum | 7d8b509 | 1991-09-10 14:53:39 +0000 | [diff] [blame] | 119 | #ifdef MPW_881_BUG |
| 120 | temp = 0xFFFF & |
| 121 | (a->a_arrow | (1 << 7) | |
| 122 | ((type - NT_OFFSET) << 8)); |
| 123 | accel[ibit] = temp; |
| 124 | #else |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 125 | accel[ibit] = a->a_arrow | (1 << 7) | |
| 126 | ((type - NT_OFFSET) << 8); |
Guido van Rossum | 7d8b509 | 1991-09-10 14:53:39 +0000 | [diff] [blame] | 127 | #endif |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 128 | } |
| 129 | } |
| 130 | } |
| 131 | else if (lbl == EMPTY) |
| 132 | s->s_accept = 1; |
| 133 | else if (lbl >= 0 && lbl < nl) |
| 134 | accel[lbl] = a->a_arrow; |
| 135 | } |
| 136 | while (nl > 0 && accel[nl-1] == -1) |
| 137 | nl--; |
| 138 | for (k = 0; k < nl && accel[k] == -1;) |
| 139 | k++; |
| 140 | if (k < nl) { |
| 141 | int i; |
| 142 | s->s_accel = NEW(int, nl-k); |
| 143 | if (s->s_accel == NULL) { |
| 144 | fprintf(stderr, "no mem to add parser accelerators\n"); |
| 145 | exit(1); |
| 146 | } |
| 147 | s->s_lower = k; |
| 148 | s->s_upper = nl; |
| 149 | for (i = 0; k < nl; i++, k++) |
| 150 | s->s_accel[i] = accel[k]; |
| 151 | } |
| 152 | DEL(accel); |
| 153 | } |