X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/d2729d44ab05f89e96d199ad6b10e127c1cb0a38..9703cc49e0f3518e136b435b6cbcae3263eb7b7a:/src/lalr.c diff --git a/src/lalr.c b/src/lalr.c index dc0b043c..4b11caaa 100644 --- a/src/lalr.c +++ b/src/lalr.c @@ -1,98 +1,55 @@ /* Compute look-ahead criteria for bison, - Copyright (C) 1984, 1986, 1989 Free Software Foundation, Inc. + Copyright 1984, 1986, 1989, 2000 Free Software Foundation, Inc. -This file is part of Bison, the GNU Compiler Compiler. + 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 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. + 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. */ + 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, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ -/* Compute how to make the finite state machine deterministic; - find which rules need lookahead in each state, and which lookahead tokens they accept. +/* Compute how to make the finite state machine deterministic; find + which rules need lookahead in each state, and which lookahead + tokens they accept. */ -lalr(), the entry point, builds these data structures: - -goto_map, from_state and to_state - record each shift transition which accepts a variable (a nonterminal). -ngotos is the number of such transitions. -from_state[t] is the state number which a transition leads from -and to_state[t] is the state number it leads to. -All the transitions that accept a particular variable are grouped together and -goto_map[i - ntokens] is the index in from_state and to_state of the first of them. - -consistent[s] is nonzero if no lookahead is needed to decide what to do in state s. - -LAruleno is a vector which records the rules that need lookahead in various states. -The elements of LAruleno that apply to state s are those from - lookaheads[s] through lookaheads[s+1]-1. -Each element of LAruleno is a rule number. - -If lr is the length of LAruleno, then a number from 0 to lr-1 -can specify both a rule and a state where the rule might be applied. - -LA is a lr by ntokens matrix of bits. -LA[l, i] is 1 if the rule LAruleno[l] is applicable in the appropriate state - when the next token is symbol i. -If LA[l, i] and LA[l, j] are both 1 for i != j, it is a conflict. -*/ - -#include #include "system.h" -#include "machine.h" #include "types.h" -#include "state.h" -#include "alloc.h" +#include "LR0.h" #include "gram.h" +#include "complain.h" +#include "lalr.h" +#include "nullable.h" +#include "derives.h" - -extern short **derives; -extern char *nullable; - +/* All the decorated states, indexed by the state number. Warning: + there is a state_TABLE in LR0.c, but it is different and static. + */ +state_t *state_table = NULL; int tokensetsize; short *lookaheads; short *LAruleno; unsigned *LA; -short *accessing_symbol; + char *consistent; -core **state_table; shifts **shift_table; reductions **reduction_table; short *goto_map; short *from_state; short *to_state; -void lalr PARAMS((void)); -short **transpose PARAMS((short **, int)); -void set_state_table PARAMS((void)); -void set_accessing_symbol PARAMS((void)); -void set_shift_table PARAMS((void)); -void set_reduction_table PARAMS((void)); -void set_maxrhs PARAMS((void)); -void initialize_LA PARAMS((void)); -void set_goto_map PARAMS((void)); -int map_goto PARAMS((int, int)); -void initialize_F PARAMS((void)); -void build_relations PARAMS((void)); -void add_lookback_edge PARAMS((int, int, int)); -void compute_FOLLOWS PARAMS((void)); -void compute_lookaheads PARAMS((void)); -void digraph PARAMS((short **)); -void traverse PARAMS((register int)); - -extern void toomany PARAMS((char *)); -extern void berror PARAMS((char *)); +extern void berror PARAMS ((const char *)); static int infinity; static int maxrhs; @@ -106,79 +63,133 @@ static short *VERTICES; static int top; -void -lalr (void) +static void +traverse (int i) { - tokensetsize = WORDSIZE(ntokens); - - set_state_table(); - set_accessing_symbol(); - set_shift_table(); - set_reduction_table(); - set_maxrhs(); - initialize_LA(); - set_goto_map(); - initialize_F(); - build_relations(); - compute_FOLLOWS(); - compute_lookaheads(); + unsigned *fp1; + unsigned *fp2; + unsigned *fp3; + int j; + short *rp; + + int height; + unsigned *base; + + VERTICES[++top] = i; + INDEX[i] = height = top; + + base = F + i * tokensetsize; + fp3 = base + tokensetsize; + + rp = R[i]; + if (rp) + { + while ((j = *rp++) >= 0) + { + if (INDEX[j] == 0) + traverse (j); + + if (INDEX[i] > INDEX[j]) + INDEX[i] = INDEX[j]; + + fp1 = base; + fp2 = F + j * tokensetsize; + + while (fp1 < fp3) + *fp1++ |= *fp2++; + } + } + + if (INDEX[i] == height) + { + for (;;) + { + j = VERTICES[top--]; + INDEX[j] = infinity; + + if (i == j) + break; + + fp1 = base; + fp2 = F + j * tokensetsize; + + while (fp1 < fp3) + *fp2++ = *fp1++; + } + } } -void -set_state_table (void) +static void +digraph (short **relation) { - register core *sp; + int i; - state_table = NEW2(nstates, core *); + infinity = ngotos + 2; + INDEX = XCALLOC (short, ngotos + 1); + VERTICES = XCALLOC (short, ngotos + 1); + top = 0; - for (sp = first_state; sp; sp = sp->next) - state_table[sp->number] = sp; -} + R = relation; + for (i = 0; i < ngotos; i++) + INDEX[i] = 0; -void -set_accessing_symbol (void) + for (i = 0; i < ngotos; i++) + { + if (INDEX[i] == 0 && R[i]) + traverse (i); + } + + XFREE (INDEX); + XFREE (VERTICES); +} + +static void +set_state_table (void) { - register core *sp; + core *sp; - accessing_symbol = NEW2(nstates, short); + state_table = XCALLOC (state_t, nstates); for (sp = first_state; sp; sp = sp->next) - accessing_symbol[sp->number] = sp->accessing_symbol; + { + state_table[sp->number].state = sp; + state_table[sp->number].accessing_symbol = sp->accessing_symbol; + } } -void +static void set_shift_table (void) { - register shifts *sp; + shifts *sp; - shift_table = NEW2(nstates, shifts *); + shift_table = XCALLOC (shifts *, nstates); for (sp = first_shift; sp; sp = sp->next) shift_table[sp->number] = sp; } -void +static void set_reduction_table (void) { - register reductions *rp; + reductions *rp; - reduction_table = NEW2(nstates, reductions *); + reduction_table = XCALLOC (reductions *, nstates); for (rp = first_reduction; rp; rp = rp->next) reduction_table[rp->number] = rp; } -void +static void set_maxrhs (void) { - register short *itemp; - register int length; - register int max; + short *itemp; + int length; + int max; length = 0; max = 0; @@ -190,7 +201,8 @@ set_maxrhs (void) } else { - if (length > max) max = length; + if (length > max) + max = length; length = 0; } } @@ -199,58 +211,58 @@ set_maxrhs (void) } -void +static void initialize_LA (void) { - register int i; - register int j; - register int count; - register reductions *rp; - register shifts *sp; - register short *np; + int i; + int j; + int count; + reductions *rp; + shifts *sp; + short *np; - consistent = NEW2(nstates, char); - lookaheads = NEW2(nstates + 1, short); + consistent = XCALLOC (char, nstates); + lookaheads = XCALLOC (short, nstates + 1); count = 0; for (i = 0; i < nstates; i++) { - register int k; + int k; lookaheads[i] = count; rp = reduction_table[i]; sp = shift_table[i]; - if (rp && (rp->nreds > 1 - || (sp && ! ISVAR(accessing_symbol[sp->shifts[0]])))) + if (rp + && (rp->nreds > 1 + || (sp && !ISVAR (state_table[sp->shifts[0]].accessing_symbol)))) count += rp->nreds; else consistent[i] = 1; if (sp) for (k = 0; k < sp->nshifts; k++) - { - if (accessing_symbol[sp->shifts[k]] == error_token_number) - { - consistent[i] = 0; - break; - } - } + if (state_table[sp->shifts[k]].accessing_symbol + == error_token_number) + { + consistent[i] = 0; + break; + } } lookaheads[nstates] = count; if (count == 0) { - LA = NEW2(1 * tokensetsize, unsigned); - LAruleno = NEW2(1, short); - lookback = NEW2(1, shorts *); + LA = XCALLOC (unsigned, 1 * tokensetsize); + LAruleno = XCALLOC (short, 1); + lookback = XCALLOC (shorts *, 1); } else { - LA = NEW2(count * tokensetsize, unsigned); - LAruleno = NEW2(count, short); - lookback = NEW2(count, shorts *); + LA = XCALLOC (unsigned, count * tokensetsize); + LAruleno = XCALLOC (short, count); + lookback = XCALLOC (shorts *, count); } np = LAruleno; @@ -266,35 +278,36 @@ initialize_LA (void) } -void +static void set_goto_map (void) { - register shifts *sp; - register int i; - register int symbol; - register int k; - register short *temp_map; - register int state2; - register int state1; + shifts *sp; + int i; + int symbol; + int k; + short *temp_map; + int state2; + int state1; - goto_map = NEW2(nvars + 1, short) - ntokens; - temp_map = NEW2(nvars + 1, short) - ntokens; + goto_map = XCALLOC (short, nvars + 1) - ntokens; + temp_map = XCALLOC (short, nvars + 1) - ntokens; ngotos = 0; for (sp = first_shift; sp; sp = sp->next) { for (i = sp->nshifts - 1; i >= 0; i--) { - symbol = accessing_symbol[sp->shifts[i]]; + symbol = state_table[sp->shifts[i]].accessing_symbol; - if (ISTOKEN(symbol)) break; + if (ISTOKEN (symbol)) + break; if (ngotos == MAXSHORT) - toomany(_("gotos")); + fatal (_("too many gotos (max %d)"), MAXSHORT); ngotos++; goto_map[symbol]++; - } + } } k = 0; @@ -310,8 +323,8 @@ set_goto_map (void) goto_map[nsyms] = ngotos; temp_map[nsyms] = ngotos; - from_state = NEW2(ngotos, short); - to_state = NEW2(ngotos, short); + from_state = XCALLOC (short, ngotos); + to_state = XCALLOC (short, ngotos); for (sp = first_shift; sp; sp = sp->next) { @@ -319,9 +332,10 @@ set_goto_map (void) for (i = sp->nshifts - 1; i >= 0; i--) { state2 = sp->shifts[i]; - symbol = accessing_symbol[state2]; + symbol = state_table[state2].accessing_symbol; - if (ISTOKEN(symbol)) break; + if (ISTOKEN (symbol)) + break; k = temp_map[symbol]++; from_state[k] = state1; @@ -329,20 +343,22 @@ set_goto_map (void) } } - FREE(temp_map + ntokens); + XFREE (temp_map + ntokens); } -/* Map_goto maps a state/symbol pair into its numeric representation. */ +/*----------------------------------------------------------. +| Map a state/symbol pair into its numeric representation. | +`----------------------------------------------------------*/ -int +static int map_goto (int state, int symbol) { - register int high; - register int low; - register int middle; - register int s; + int high; + int low; + int middle; + int s; low = goto_map[symbol]; high = goto_map[symbol + 1] - 1; @@ -352,40 +368,40 @@ map_goto (int state, int symbol) middle = (low + high) / 2; s = from_state[middle]; if (s == state) - return (middle); + return middle; else if (s < state) low = middle + 1; else high = middle - 1; } - berror("map_goto"); -/* NOTREACHED */ + assert (0); + /* NOTREACHED */ return 0; } -void +static void initialize_F (void) { - register int i; - register int j; - register int k; - register shifts *sp; - register short *edge; - register unsigned *rowp; - register short *rp; - register short **reads; - register int nedges; - register int stateno; - register int symbol; - register int nwords; + int i; + int j; + int k; + shifts *sp; + short *edge; + unsigned *rowp; + short *rp; + short **reads; + int nedges; + int stateno; + int symbol; + int nwords; nwords = ngotos * tokensetsize; - F = NEW2(nwords, unsigned); + F = XCALLOC (unsigned, nwords); - reads = NEW2(ngotos, short *); - edge = NEW2(ngotos + 1, short); + reads = XCALLOC (short *, ngotos); + edge = XCALLOC (short, ngotos + 1); nedges = 0; rowp = F; @@ -400,22 +416,22 @@ initialize_F (void) for (j = 0; j < k; j++) { - symbol = accessing_symbol[sp->shifts[j]]; - if (ISVAR(symbol)) + symbol = state_table[sp->shifts[j]].accessing_symbol; + if (ISVAR (symbol)) break; - SETBIT(rowp, symbol); + SETBIT (rowp, symbol); } for (; j < k; j++) { - symbol = accessing_symbol[sp->shifts[j]]; + symbol = state_table[sp->shifts[j]].accessing_symbol; if (nullable[symbol]) - edge[nedges++] = map_goto(stateno, symbol); + edge[nedges++] = map_goto (stateno, symbol); } - + if (nedges) { - reads[i] = rp = NEW2(nedges + 1, short); + reads[i] = rp = XCALLOC (short, nedges + 1); for (j = 0; j < nedges; j++) rp[j] = edge[j]; @@ -428,121 +444,26 @@ initialize_F (void) rowp += tokensetsize; } - digraph(reads); + digraph (reads); for (i = 0; i < ngotos; i++) { if (reads[i]) - FREE(reads[i]); + XFREE (reads[i]); } - FREE(reads); - FREE(edge); + XFREE (reads); + XFREE (edge); } -void -build_relations (void) -{ - register int i; - register int j; - register int k; - register short *rulep; - register short *rp; - register shifts *sp; - register int length; - register int nedges; - register int done; - register int state1; - register int stateno; - register int symbol1; - register int symbol2; - register short *shortp; - register short *edge; - register short *states; - register short **new_includes; - - includes = NEW2(ngotos, short *); - edge = NEW2(ngotos + 1, short); - states = NEW2(maxrhs + 1, short); - - for (i = 0; i < ngotos; i++) - { - nedges = 0; - state1 = from_state[i]; - symbol1 = accessing_symbol[to_state[i]]; - - for (rulep = derives[symbol1]; *rulep > 0; rulep++) - { - length = 1; - states[0] = state1; - stateno = state1; - - for (rp = ritem + rrhs[*rulep]; *rp > 0; rp++) - { - symbol2 = *rp; - sp = shift_table[stateno]; - k = sp->nshifts; - - for (j = 0; j < k; j++) - { - stateno = sp->shifts[j]; - if (accessing_symbol[stateno] == symbol2) break; - } - - states[length++] = stateno; - } - - if (!consistent[stateno]) - add_lookback_edge(stateno, *rulep, i); - - length--; - done = 0; - while (!done) - { - done = 1; - rp--; - /* JF added rp>=ritem && I hope to god its right! */ - if (rp>=ritem && ISVAR(*rp)) - { - stateno = states[--length]; - edge[nedges++] = map_goto(stateno, *rp); - if (nullable[*rp]) done = 0; - } - } - } - - if (nedges) - { - includes[i] = shortp = NEW2(nedges + 1, short); - for (j = 0; j < nedges; j++) - shortp[j] = edge[j]; - shortp[nedges] = -1; - } - } - - new_includes = transpose(includes, ngotos); - - for (i = 0; i < ngotos; i++) - if (includes[i]) - FREE(includes[i]); - - FREE(includes); - - includes = new_includes; - - FREE(edge); - FREE(states); -} - - -void +static void add_lookback_edge (int stateno, int ruleno, int gotono) { - register int i; - register int k; - register int found; - register shorts *sp; + int i; + int k; + int found; + shorts *sp; i = lookaheads[stateno]; k = lookaheads[stateno + 1]; @@ -555,28 +476,26 @@ add_lookback_edge (int stateno, int ruleno, int gotono) i++; } - if (found == 0) - berror("add_lookback_edge"); + assert (found); - sp = NEW(shorts); + sp = XCALLOC (shorts, 1); sp->next = lookback[i]; sp->value = gotono; lookback[i] = sp; } - -short ** +static short ** transpose (short **R_arg, int n) { - register short **new_R; - register short **temp_R; - register short *nedges; - register short *sp; - register int i; - register int k; + short **new_R; + short **temp_R; + short *nedges; + short *sp; + int i; + int k; - nedges = NEW2(n, short); + nedges = XCALLOC (short, n); for (i = 0; i < n; i++) { @@ -588,22 +507,22 @@ transpose (short **R_arg, int n) } } - new_R = NEW2(n, short *); - temp_R = NEW2(n, short *); + new_R = XCALLOC (short *, n); + temp_R = XCALLOC (short *, n); for (i = 0; i < n; i++) { k = nedges[i]; if (k > 0) { - sp = NEW2(k + 1, short); + sp = XCALLOC (short, k + 1); new_R[i] = sp; temp_R[i] = sp; sp[k] = -1; } } - FREE(nedges); + XFREE (nedges); for (i = 0; i < n; i++) { @@ -615,149 +534,183 @@ transpose (short **R_arg, int n) } } - FREE(temp_R); + XFREE (temp_R); - return (new_R); + return new_R; } -void -compute_FOLLOWS (void) +static void +build_relations (void) { - register int i; - - digraph(includes); + int i; + int j; + int k; + short *rulep; + short *rp; + shifts *sp; + int length; + int nedges; + int done; + int state1; + int stateno; + int symbol1; + int symbol2; + short *shortp; + short *edge; + short *states; + short **new_includes; + + includes = XCALLOC (short *, ngotos); + edge = XCALLOC (short, ngotos + 1); + states = XCALLOC (short, maxrhs + 1); for (i = 0; i < ngotos; i++) { - if (includes[i]) FREE(includes[i]); - } + nedges = 0; + state1 = from_state[i]; + symbol1 = state_table[to_state[i]].accessing_symbol; - FREE(includes); -} + for (rulep = derives[symbol1]; *rulep > 0; rulep++) + { + length = 1; + states[0] = state1; + stateno = state1; + for (rp = ritem + rrhs[*rulep]; *rp > 0; rp++) + { + symbol2 = *rp; + sp = shift_table[stateno]; + k = sp->nshifts; -void -compute_lookaheads (void) -{ - register int i; - register int n; - register unsigned *fp1; - register unsigned *fp2; - register unsigned *fp3; - register shorts *sp; - register unsigned *rowp; -/* register short *rulep; JF unused */ -/* register int count; JF unused */ - register shorts *sptmp;/* JF */ + for (j = 0; j < k; j++) + { + stateno = sp->shifts[j]; + if (state_table[stateno].accessing_symbol == symbol2) + break; + } - rowp = LA; - n = lookaheads[nstates]; - for (i = 0; i < n; i++) - { - fp3 = rowp + tokensetsize; - for (sp = lookback[i]; sp; sp = sp->next) - { - fp1 = rowp; - fp2 = F + tokensetsize * sp->value; - while (fp1 < fp3) - *fp1++ |= *fp2++; + states[length++] = stateno; + } + + if (!consistent[stateno]) + add_lookback_edge (stateno, *rulep, i); + + length--; + done = 0; + while (!done) + { + done = 1; + rp--; + /* JF added rp>=ritem && I hope to god its right! */ + if (rp >= ritem && ISVAR (*rp)) + { + stateno = states[--length]; + edge[nedges++] = map_goto (stateno, *rp); + if (nullable[*rp]) + done = 0; + } + } } - rowp = fp3; + if (nedges) + { + includes[i] = shortp = XCALLOC (short, nedges + 1); + for (j = 0; j < nedges; j++) + shortp[j] = edge[j]; + shortp[nedges] = -1; + } } - for (i = 0; i < n; i++) - {/* JF removed ref to freed storage */ - for (sp = lookback[i]; sp; sp = sptmp) { - sptmp=sp->next; - FREE(sp); - } - } + new_includes = transpose (includes, ngotos); - FREE(lookback); - FREE(F); -} + for (i = 0; i < ngotos; i++) + if (includes[i]) + XFREE (includes[i]); + XFREE (includes); -void -digraph (short **relation) -{ - register int i; + includes = new_includes; - infinity = ngotos + 2; - INDEX = NEW2(ngotos + 1, short); - VERTICES = NEW2(ngotos + 1, short); - top = 0; + XFREE (edge); + XFREE (states); +} - R = relation; - for (i = 0; i < ngotos; i++) - INDEX[i] = 0; + +static void +compute_FOLLOWS (void) +{ + int i; + + digraph (includes); for (i = 0; i < ngotos; i++) { - if (INDEX[i] == 0 && R[i]) - traverse(i); + if (includes[i]) + XFREE (includes[i]); } - FREE(INDEX); - FREE(VERTICES); + XFREE (includes); } -void -traverse (register int i) +static void +compute_lookaheads (void) { - register unsigned *fp1; - register unsigned *fp2; - register unsigned *fp3; - register int j; - register short *rp; + int i; + int n; + unsigned *fp1; + unsigned *fp2; + unsigned *fp3; + shorts *sp; + unsigned *rowp; + shorts *sptmp; /* JF */ - int height; - unsigned *base; - - VERTICES[++top] = i; - INDEX[i] = height = top; - - base = F + i * tokensetsize; - fp3 = base + tokensetsize; - - rp = R[i]; - if (rp) + rowp = LA; + n = lookaheads[nstates]; + for (i = 0; i < n; i++) { - while ((j = *rp++) >= 0) + fp3 = rowp + tokensetsize; + for (sp = lookback[i]; sp; sp = sp->next) { - if (INDEX[j] == 0) - traverse(j); - - if (INDEX[i] > INDEX[j]) - INDEX[i] = INDEX[j]; - - fp1 = base; - fp2 = F + j * tokensetsize; - + fp1 = rowp; + fp2 = F + tokensetsize * sp->value; while (fp1 < fp3) *fp1++ |= *fp2++; } + + rowp = fp3; } - if (INDEX[i] == height) + for (i = 0; i < n; i++) { - for (;;) + /* JF removed ref to freed storage */ + for (sp = lookback[i]; sp; sp = sptmp) { - j = VERTICES[top--]; - INDEX[j] = infinity; + sptmp = sp->next; + XFREE (sp); + } + } - if (i == j) - break; + XFREE (lookback); + XFREE (F); +} - fp1 = base; - fp2 = F + j * tokensetsize; - while (fp1 < fp3) - *fp2++ = *fp1++; - } - } +void +lalr (void) +{ + tokensetsize = WORDSIZE (ntokens); + + set_state_table (); + set_shift_table (); + set_reduction_table (); + set_maxrhs (); + initialize_LA (); + set_goto_map (); + initialize_F (); + build_relations (); + compute_FOLLOWS (); + compute_lookaheads (); }