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Diffstat (limited to 'ocaml-binary-annot/yacc/lr0.c')
| -rw-r--r-- | ocaml-binary-annot/yacc/lr0.c | 621 |
1 files changed, 621 insertions, 0 deletions
diff --git a/ocaml-binary-annot/yacc/lr0.c b/ocaml-binary-annot/yacc/lr0.c new file mode 100644 index 0000000000..e05fcb072a --- /dev/null +++ b/ocaml-binary-annot/yacc/lr0.c @@ -0,0 +1,621 @@ +/***********************************************************************/ +/* */ +/* Objective Caml */ +/* */ +/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */ +/* */ +/* Copyright 1996 Institut National de Recherche en Informatique et */ +/* en Automatique. All rights reserved. This file is distributed */ +/* under the terms of the Q Public License version 1.0. */ +/* */ +/***********************************************************************/ + +/* Based on public-domain code from Berkeley Yacc */ + +/* $Id$ */ + + +#include "defs.h" + +extern short *itemset; +extern short *itemsetend; +extern unsigned *ruleset; + +int nstates; +core *first_state; +shifts *first_shift; +reductions *first_reduction; + +int get_state(int symbol); +core *new_state(int symbol); + +static core **state_set; +static core *this_state; +static core *last_state; +static shifts *last_shift; +static reductions *last_reduction; + +static int nshifts; +static short *shift_symbol; + +static short *redset; +static short *shiftset; + +static short **kernel_base; +static short **kernel_end; +static short *kernel_items; + + + +void initialize_states (void); +void save_reductions (void); +void new_itemsets (void); +void save_shifts (void); +void print_derives (); +void show_cores (void), show_ritems (void), show_rrhs (void), show_shifts (void); + +void allocate_itemsets(void) +{ + register short *itemp; + register short *item_end; + register int symbol; + register int i; + register int count; + register int max; + register short *symbol_count; + + count = 0; + symbol_count = NEW2(nsyms, short); + + item_end = ritem + nitems; + for (itemp = ritem; itemp < item_end; itemp++) + { + symbol = *itemp; + if (symbol >= 0) + { + count++; + symbol_count[symbol]++; + } + } + + kernel_base = NEW2(nsyms, short *); + kernel_items = NEW2(count, short); + + count = 0; + max = 0; + for (i = 0; i < nsyms; i++) + { + kernel_base[i] = kernel_items + count; + count += symbol_count[i]; + if (max < symbol_count[i]) + max = symbol_count[i]; + } + + shift_symbol = symbol_count; + kernel_end = NEW2(nsyms, short *); +} + + +void allocate_storage(void) +{ + allocate_itemsets(); + shiftset = NEW2(nsyms, short); + redset = NEW2(nrules + 1, short); + state_set = NEW2(nitems, core *); +} + + +void append_states(void) +{ + register int i; + register int j; + register int symbol; + +#ifdef TRACE + fprintf(stderr, "Entering append_states()\n"); +#endif + for (i = 1; i < nshifts; i++) + { + symbol = shift_symbol[i]; + j = i; + while (j > 0 && shift_symbol[j - 1] > symbol) + { + shift_symbol[j] = shift_symbol[j - 1]; + j--; + } + shift_symbol[j] = symbol; + } + + for (i = 0; i < nshifts; i++) + { + symbol = shift_symbol[i]; + shiftset[i] = get_state(symbol); + } +} + + +void free_storage(void) +{ + FREE(shift_symbol); + FREE(redset); + FREE(shiftset); + FREE(kernel_base); + FREE(kernel_end); + FREE(kernel_items); + FREE(state_set); +} + + + +void generate_states(void) +{ + allocate_storage(); + itemset = NEW2(nitems, short); + ruleset = NEW2(WORDSIZE(nrules), unsigned); + set_first_derives(); + initialize_states(); + + while (this_state) + { + closure(this_state->items, this_state->nitems); + save_reductions(); + new_itemsets(); + append_states(); + + if (nshifts > 0) + save_shifts(); + + this_state = this_state->next; + } + + finalize_closure(); + free_storage(); +} + + + +int +get_state(int symbol) +{ + register int key; + register short *isp1; + register short *isp2; + register short *iend; + register core *sp; + register int found; + register int n; + +#ifdef TRACE + fprintf(stderr, "Entering get_state(%d)\n", symbol); +#endif + + isp1 = kernel_base[symbol]; + iend = kernel_end[symbol]; + n = iend - isp1; + + key = *isp1; + assert(0 <= key && key < nitems); + sp = state_set[key]; + if (sp) + { + found = 0; + while (!found) + { + if (sp->nitems == n) + { + found = 1; + isp1 = kernel_base[symbol]; + isp2 = sp->items; + + while (found && isp1 < iend) + { + if (*isp1++ != *isp2++) + found = 0; + } + } + + if (!found) + { + if (sp->link) + { + sp = sp->link; + } + else + { + sp = sp->link = new_state(symbol); + found = 1; + } + } + } + } + else + { + state_set[key] = sp = new_state(symbol); + } + + return (sp->number); +} + + + +void initialize_states(void) +{ + register int i; + register short *start_derives; + register core *p; + + start_derives = derives[start_symbol]; + for (i = 0; start_derives[i] >= 0; ++i) + continue; + + p = (core *) MALLOC(sizeof(core) + i*sizeof(short)); + if (p == 0) no_space(); + + p->next = 0; + p->link = 0; + p->number = 0; + p->accessing_symbol = 0; + p->nitems = i; + + for (i = 0; start_derives[i] >= 0; ++i) + p->items[i] = rrhs[start_derives[i]]; + + first_state = last_state = this_state = p; + nstates = 1; +} + + +void new_itemsets(void) +{ + register int i; + register int shiftcount; + register short *isp; + register short *ksp; + register int symbol; + + for (i = 0; i < nsyms; i++) + kernel_end[i] = 0; + + shiftcount = 0; + isp = itemset; + while (isp < itemsetend) + { + i = *isp++; + symbol = ritem[i]; + if (symbol > 0) + { + ksp = kernel_end[symbol]; + if (!ksp) + { + shift_symbol[shiftcount++] = symbol; + ksp = kernel_base[symbol]; + } + + *ksp++ = i + 1; + kernel_end[symbol] = ksp; + } + } + + nshifts = shiftcount; +} + + + +core * +new_state(int symbol) +{ + register int n; + register core *p; + register short *isp1; + register short *isp2; + register short *iend; + +#ifdef TRACE + fprintf(stderr, "Entering new_state(%d)\n", symbol); +#endif + + if (nstates >= MAXSHORT) + fatal("too many states"); + + isp1 = kernel_base[symbol]; + iend = kernel_end[symbol]; + n = iend - isp1; + + p = (core *) allocate((unsigned) (sizeof(core) + (n - 1) * sizeof(short))); + p->accessing_symbol = symbol; + p->number = nstates; + p->nitems = n; + + isp2 = p->items; + while (isp1 < iend) + *isp2++ = *isp1++; + + last_state->next = p; + last_state = p; + + nstates++; + + return (p); +} + + +/* show_cores is used for debugging */ + +void show_cores(void) +{ + core *p; + int i, j, k, n; + int itemno; + + k = 0; + for (p = first_state; p; ++k, p = p->next) + { + if (k) printf("\n"); + printf("state %d, number = %d, accessing symbol = %s\n", + k, p->number, symbol_name[p->accessing_symbol]); + n = p->nitems; + for (i = 0; i < n; ++i) + { + itemno = p->items[i]; + printf("%4d ", itemno); + j = itemno; + while (ritem[j] >= 0) ++j; + printf("%s :", symbol_name[rlhs[-ritem[j]]]); + j = rrhs[-ritem[j]]; + while (j < itemno) + printf(" %s", symbol_name[ritem[j++]]); + printf(" ."); + while (ritem[j] >= 0) + printf(" %s", symbol_name[ritem[j++]]); + printf("\n"); + fflush(stdout); + } + } +} + + +/* show_ritems is used for debugging */ + +void show_ritems(void) +{ + int i; + + for (i = 0; i < nitems; ++i) + printf("ritem[%d] = %d\n", i, ritem[i]); +} + + +/* show_rrhs is used for debugging */ + +void show_rrhs(void) +{ + int i; + + for (i = 0; i < nrules; ++i) + printf("rrhs[%d] = %d\n", i, rrhs[i]); +} + + +/* show_shifts is used for debugging */ + +void show_shifts(void) +{ + shifts *p; + int i, j, k; + + k = 0; + for (p = first_shift; p; ++k, p = p->next) + { + if (k) printf("\n"); + printf("shift %d, number = %d, nshifts = %d\n", k, p->number, + p->nshifts); + j = p->nshifts; + for (i = 0; i < j; ++i) + printf("\t%d\n", p->shift[i]); + } +} + + +void save_shifts(void) +{ + register shifts *p; + register short *sp1; + register short *sp2; + register short *send; + + p = (shifts *) allocate((unsigned) (sizeof(shifts) + + (nshifts - 1) * sizeof(short))); + + p->number = this_state->number; + p->nshifts = nshifts; + + sp1 = shiftset; + sp2 = p->shift; + send = shiftset + nshifts; + + while (sp1 < send) + *sp2++ = *sp1++; + + if (last_shift) + { + last_shift->next = p; + last_shift = p; + } + else + { + first_shift = p; + last_shift = p; + } +} + + + +void save_reductions(void) +{ + register short *isp; + register short *rp1; + register short *rp2; + register int item; + register int count; + register reductions *p; + register short *rend; + + count = 0; + for (isp = itemset; isp < itemsetend; isp++) + { + item = ritem[*isp]; + if (item < 0) + { + redset[count++] = -item; + } + } + + if (count) + { + p = (reductions *) allocate((unsigned) (sizeof(reductions) + + (count - 1) * sizeof(short))); + + p->number = this_state->number; + p->nreds = count; + + rp1 = redset; + rp2 = p->rules; + rend = rp1 + count; + + while (rp1 < rend) + *rp2++ = *rp1++; + + if (last_reduction) + { + last_reduction->next = p; + last_reduction = p; + } + else + { + first_reduction = p; + last_reduction = p; + } + } +} + + +void set_derives(void) +{ + register int i, k; + register int lhs; + register short *rules; + + derives = NEW2(nsyms, short *); + rules = NEW2(nvars + nrules, short); + + k = 0; + for (lhs = start_symbol; lhs < nsyms; lhs++) + { + derives[lhs] = rules + k; + for (i = 0; i < nrules; i++) + { + if (rlhs[i] == lhs) + { + rules[k] = i; + k++; + } + } + rules[k] = -1; + k++; + } + +#ifdef DEBUG + print_derives(); +#endif +} + +void free_derives(void) +{ + FREE(derives[start_symbol]); + FREE(derives); +} + +#ifdef DEBUG +void print_derives(void) +{ + register int i; + register short *sp; + + printf("\nDERIVES\n\n"); + + for (i = start_symbol; i < nsyms; i++) + { + printf("%s derives ", symbol_name[i]); + for (sp = derives[i]; *sp >= 0; sp++) + { + printf(" %d", *sp); + } + putchar('\n'); + } + + putchar('\n'); +} +#endif + + +void set_nullable(void) +{ + register int i, j; + register int empty; + int done; + + nullable = MALLOC(nsyms); + if (nullable == 0) no_space(); + + for (i = 0; i < nsyms; ++i) + nullable[i] = 0; + + done = 0; + while (!done) + { + done = 1; + for (i = 1; i < nitems; i++) + { + empty = 1; + while ((j = ritem[i]) >= 0) + { + if (!nullable[j]) + empty = 0; + ++i; + } + if (empty) + { + j = rlhs[-j]; + if (!nullable[j]) + { + nullable[j] = 1; + done = 0; + } + } + } + } + +#ifdef DEBUG + for (i = 0; i < nsyms; i++) + { + if (nullable[i]) + printf("%s is nullable\n", symbol_name[i]); + else + printf("%s is not nullable\n", symbol_name[i]); + } +#endif +} + + +void free_nullable(void) +{ + FREE(nullable); +} + + +void lr0(void) +{ + set_derives(); + set_nullable(); + generate_states(); +} |