mirror of https://github.com/python/cpython
102 lines
1.8 KiB
C
102 lines
1.8 KiB
C
/* Parser accelerator module */
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#include <stdio.h>
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#include "PROTO.h"
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#include "grammar.h"
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#include "token.h"
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#include "malloc.h"
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static void
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fixstate(g, d, s)
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grammar *g;
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dfa *d;
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state *s;
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{
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arc *a;
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int k;
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int *accel;
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int nl = g->g_ll.ll_nlabels;
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s->s_accept = 0;
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accel = NEW(int, nl);
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for (k = 0; k < nl; k++)
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accel[k] = -1;
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a = s->s_arc;
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for (k = s->s_narcs; --k >= 0; a++) {
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int lbl = a->a_lbl;
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label *l = &g->g_ll.ll_label[lbl];
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int type = l->lb_type;
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if (a->a_arrow >= (1 << 7)) {
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printf("XXX too many states!\n");
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continue;
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}
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if (ISNONTERMINAL(type)) {
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dfa *d1 = finddfa(g, type);
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int ibit;
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if (type - NT_OFFSET >= (1 << 7)) {
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printf("XXX too high nonterminal number!\n");
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continue;
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}
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for (ibit = 0; ibit < g->g_ll.ll_nlabels; ibit++) {
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if (testbit(d1->d_first, ibit)) {
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if (accel[ibit] != -1)
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printf("XXX ambiguity!\n");
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accel[ibit] = a->a_arrow | (1 << 7) |
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((type - NT_OFFSET) << 8);
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}
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}
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}
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else if (lbl == EMPTY)
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s->s_accept = 1;
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else if (lbl >= 0 && lbl < nl)
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accel[lbl] = a->a_arrow;
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}
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while (nl > 0 && accel[nl-1] == -1)
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nl--;
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for (k = 0; k < nl && accel[k] == -1;)
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k++;
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if (k < nl) {
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int i;
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s->s_accel = NEW(int, nl-k);
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if (s->s_accel == NULL) {
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fprintf(stderr, "no mem to add parser accelerators\n");
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exit(1);
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}
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s->s_lower = k;
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s->s_upper = nl;
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for (i = 0; k < nl; i++, k++)
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s->s_accel[i] = accel[k];
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}
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DEL(accel);
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}
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static void
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fixdfa(g, d)
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grammar *g;
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dfa *d;
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{
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state *s;
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int j;
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s = d->d_state;
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for (j = 0; j < d->d_nstates; j++, s++)
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fixstate(g, d, s);
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}
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void
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addaccelerators(g)
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grammar *g;
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{
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dfa *d;
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int i;
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#ifdef DEBUG
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printf("Adding parser accellerators ...\n");
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#endif
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d = g->g_dfa;
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for (i = g->g_ndfas; --i >= 0; d++)
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fixdfa(g, d);
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g->g_accel = 1;
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#ifdef DEBUG
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printf("Done.\n");
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#endif
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}
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