From 720d742f8e74acf1ade85a7d39c02fa5b9528b5a Mon Sep 17 00:00:00 2001 From: Akim Demaille Date: Mon, 2 Oct 2000 07:56:58 +0000 Subject: [PATCH] * src/lalr.h: New file. Propagate its inclusion instead of prototypes and `extern'. * src/lalr.c: Formatting changes, topological sorting etc. --- ChangeLog | 7 + src/Makefile.am | 2 +- src/conflicts.c | 9 +- src/lalr.c | 1272 +++++++++++++++++++++++------------------------ src/lalr.h | 80 +++ src/output.c | 13 +- src/print.c | 7 +- 7 files changed, 708 insertions(+), 682 deletions(-) create mode 100644 src/lalr.h diff --git a/ChangeLog b/ChangeLog index 3d7b9c87..43f0c134 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,10 @@ +2000-10-02 Akim Demaille + + * src/lalr.h: New file. + Propagate its inclusion instead of prototypes and `extern'. + * src/lalr.c: Formatting changes, topological sorting etc. + + 2000-10-02 Akim Demaille * src/output.c (token_actions): Introduce a temporary array, diff --git a/src/Makefile.am b/src/Makefile.am index 1757f65d..3dd5d6b1 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -20,7 +20,7 @@ EXTRA_bison_SOURCES = vmsgetargs.c noinst_HEADERS = alloc.h closure.h complain.h \ derives.h \ - files.h getargs.h gram.h lex.h \ + files.h getargs.h gram.h lalr.h lex.h \ output.h state.h \ symtab.h system.h types.h diff --git a/src/conflicts.c b/src/conflicts.c index 418b1072..08bc1feb 100644 --- a/src/conflicts.c +++ b/src/conflicts.c @@ -24,16 +24,9 @@ #include "files.h" #include "gram.h" #include "state.h" - +#include "lalr.h" extern char **tags; -extern int tokensetsize; -extern char *consistent; -extern short *accessing_symbol; -extern shifts **shift_table; -extern unsigned *LA; -extern short *LAruleno; -extern short *lookaheads; extern int fixed_outfiles; extern void initialize_conflicts PARAMS ((void)); diff --git a/src/lalr.c b/src/lalr.c index 6b78c995..36085271 100644 --- a/src/lalr.c +++ b/src/lalr.c @@ -19,34 +19,9 @@ 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. - -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. -*/ +/* Compute how to make the finite state machine deterministic; find + which rules need lookahead in each state, and which lookahead + tokens they accept. */ #include "system.h" #include "types.h" @@ -54,6 +29,7 @@ If LA[l, i] and LA[l, j] are both 1 for i != j, it is a conflict. #include "alloc.h" #include "gram.h" #include "complain.h" +#include "lalr.h" extern short **derives; extern char *nullable; @@ -72,26 +48,7 @@ short *goto_map; short *from_state; short *to_state; -extern void lalr PARAMS((void)); - -static short **transpose PARAMS((short **, int)); -static void set_state_table PARAMS((void)); -static void set_accessing_symbol PARAMS((void)); -static void set_shift_table PARAMS((void)); -static void set_reduction_table PARAMS((void)); -static void set_maxrhs PARAMS((void)); -static void initialize_LA PARAMS((void)); -static void set_goto_map PARAMS((void)); -static int map_goto PARAMS((int, int)); -static void initialize_F PARAMS((void)); -static void build_relations PARAMS((void)); -static void add_lookback_edge PARAMS((int, int, int)); -static void compute_FOLLOWS PARAMS((void)); -static void compute_lookaheads PARAMS((void)); -static void digraph PARAMS((short **)); -static void traverse PARAMS((register int)); - -extern void berror PARAMS((const char *)); +extern void berror PARAMS ((const char *)); static int infinity; static int maxrhs; @@ -105,614 +62,14 @@ static short *VERTICES; static int top; -void -lalr (void) -{ - 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(); -} - - static void -set_state_table (void) +traverse (int i) { - register core *sp; - - state_table = NEW2(nstates, core *); - - for (sp = first_state; sp; sp = sp->next) - state_table[sp->number] = sp; -} - - -static void -set_accessing_symbol (void) -{ - register core *sp; - - accessing_symbol = NEW2(nstates, short); - - for (sp = first_state; sp; sp = sp->next) - accessing_symbol[sp->number] = sp->accessing_symbol; -} - - -static void -set_shift_table (void) -{ - register shifts *sp; - - shift_table = NEW2(nstates, shifts *); - - for (sp = first_shift; sp; sp = sp->next) - shift_table[sp->number] = sp; -} - - -static void -set_reduction_table (void) -{ - register reductions *rp; - - reduction_table = NEW2(nstates, reductions *); - - for (rp = first_reduction; rp; rp = rp->next) - reduction_table[rp->number] = rp; -} - - -static void -set_maxrhs (void) -{ - register short *itemp; - register int length; - register int max; - - length = 0; - max = 0; - for (itemp = ritem; *itemp; itemp++) - { - if (*itemp > 0) - { - length++; - } - else - { - if (length > max) max = length; - length = 0; - } - } - - maxrhs = max; -} - - -static void -initialize_LA (void) -{ - register int i; - register int j; - register int count; - register reductions *rp; - register shifts *sp; - register short *np; - - consistent = NEW2(nstates, char); - lookaheads = NEW2(nstates + 1, short); - - count = 0; - for (i = 0; i < nstates; i++) - { - register 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]])))) - 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; - } - } - } - - lookaheads[nstates] = count; - - if (count == 0) - { - LA = NEW2(1 * tokensetsize, unsigned); - LAruleno = NEW2(1, short); - lookback = NEW2(1, shorts *); - } - else - { - LA = NEW2(count * tokensetsize, unsigned); - LAruleno = NEW2(count, short); - lookback = NEW2(count, shorts *); - } - - np = LAruleno; - for (i = 0; i < nstates; i++) - { - if (!consistent[i]) - { - if ((rp = reduction_table[i])) - for (j = 0; j < rp->nreds; j++) - *np++ = rp->rules[j]; - } - } -} - - -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; - - goto_map = NEW2(nvars + 1, short) - ntokens; - temp_map = NEW2(nvars + 1, short) - 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]]; - - if (ISTOKEN(symbol)) break; - - if (ngotos == MAXSHORT) - fatal (_("too many gotos (max %d)"), MAXSHORT); - - ngotos++; - goto_map[symbol]++; - } - } - - k = 0; - for (i = ntokens; i < nsyms; i++) - { - temp_map[i] = k; - k += goto_map[i]; - } - - for (i = ntokens; i < nsyms; i++) - goto_map[i] = temp_map[i]; - - goto_map[nsyms] = ngotos; - temp_map[nsyms] = ngotos; - - from_state = NEW2(ngotos, short); - to_state = NEW2(ngotos, short); - - for (sp = first_shift; sp; sp = sp->next) - { - state1 = sp->number; - for (i = sp->nshifts - 1; i >= 0; i--) - { - state2 = sp->shifts[i]; - symbol = accessing_symbol[state2]; - - if (ISTOKEN(symbol)) break; - - k = temp_map[symbol]++; - from_state[k] = state1; - to_state[k] = state2; - } - } - - FREE(temp_map + ntokens); -} - - - -/* Map_goto maps a state/symbol pair into its numeric representation. */ - -static int -map_goto (int state, int symbol) -{ - register int high; - register int low; - register int middle; - register int s; - - low = goto_map[symbol]; - high = goto_map[symbol + 1] - 1; - - while (low <= high) - { - middle = (low + high) / 2; - s = from_state[middle]; - if (s == state) - return middle; - else if (s < state) - low = middle + 1; - else - high = middle - 1; - } - - berror("map_goto"); -/* NOTREACHED */ - return 0; -} - - -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; - - nwords = ngotos * tokensetsize; - F = NEW2(nwords, unsigned); - - reads = NEW2(ngotos, short *); - edge = NEW2(ngotos + 1, short); - nedges = 0; - - rowp = F; - for (i = 0; i < ngotos; i++) - { - stateno = to_state[i]; - sp = shift_table[stateno]; - - if (sp) - { - k = sp->nshifts; - - for (j = 0; j < k; j++) - { - symbol = accessing_symbol[sp->shifts[j]]; - if (ISVAR(symbol)) - break; - SETBIT(rowp, symbol); - } - - for (; j < k; j++) - { - symbol = accessing_symbol[sp->shifts[j]]; - if (nullable[symbol]) - edge[nedges++] = map_goto(stateno, symbol); - } - - if (nedges) - { - reads[i] = rp = NEW2(nedges + 1, short); - - for (j = 0; j < nedges; j++) - rp[j] = edge[j]; - - rp[nedges] = -1; - nedges = 0; - } - } - - rowp += tokensetsize; - } - - digraph(reads); - - for (i = 0; i < ngotos; i++) - { - if (reads[i]) - FREE(reads[i]); - } - - FREE(reads); - FREE(edge); -} - - -static 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); -} - - -static void -add_lookback_edge (int stateno, int ruleno, int gotono) -{ - register int i; - register int k; - register int found; - register shorts *sp; - - i = lookaheads[stateno]; - k = lookaheads[stateno + 1]; - found = 0; - while (!found && i < k) - { - if (LAruleno[i] == ruleno) - found = 1; - else - i++; - } - - if (found == 0) - berror("add_lookback_edge"); - - sp = NEW(shorts); - sp->next = lookback[i]; - sp->value = gotono; - lookback[i] = sp; -} - - - -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; - - nedges = NEW2(n, short); - - for (i = 0; i < n; i++) - { - sp = R_arg[i]; - if (sp) - { - while (*sp >= 0) - nedges[*sp++]++; - } - } - - new_R = NEW2(n, short *); - temp_R = NEW2(n, short *); - - for (i = 0; i < n; i++) - { - k = nedges[i]; - if (k > 0) - { - sp = NEW2(k + 1, short); - new_R[i] = sp; - temp_R[i] = sp; - sp[k] = -1; - } - } - - FREE(nedges); - - for (i = 0; i < n; i++) - { - sp = R_arg[i]; - if (sp) - { - while (*sp >= 0) - *temp_R[*sp++]++ = i; - } - } - - FREE(temp_R); - - return new_R; -} - - -static void -compute_FOLLOWS (void) -{ - register int i; - - digraph(includes); - - for (i = 0; i < ngotos; i++) - { - if (includes[i]) FREE(includes[i]); - } - - FREE(includes); -} - - -static 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 */ - - 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++; - } - - rowp = fp3; - } - - for (i = 0; i < n; i++) - {/* JF removed ref to freed storage */ - for (sp = lookback[i]; sp; sp = sptmp) { - sptmp=sp->next; - FREE(sp); - } - } - - FREE(lookback); - FREE(F); -} - - -static void -digraph (short **relation) -{ - register int i; - - infinity = ngotos + 2; - INDEX = NEW2(ngotos + 1, short); - VERTICES = NEW2(ngotos + 1, short); - top = 0; - - R = relation; - - for (i = 0; i < ngotos; i++) - INDEX[i] = 0; - - for (i = 0; i < ngotos; i++) - { - if (INDEX[i] == 0 && R[i]) - traverse(i); - } - - FREE(INDEX); - FREE(VERTICES); -} - - -static void -traverse (register int i) -{ - register unsigned *fp1; - register unsigned *fp2; - register unsigned *fp3; - register int j; - register short *rp; + unsigned *fp1; + unsigned *fp2; + unsigned *fp3; + int j; + short *rp; int height; unsigned *base; @@ -729,7 +86,7 @@ traverse (register int i) while ((j = *rp++) >= 0) { if (INDEX[j] == 0) - traverse(j); + traverse (j); if (INDEX[i] > INDEX[j]) INDEX[i] = INDEX[j]; @@ -760,3 +117,608 @@ traverse (register int i) } } } + + +static void +digraph (short **relation) +{ + int i; + + infinity = ngotos + 2; + INDEX = NEW2 (ngotos + 1, short); + VERTICES = NEW2 (ngotos + 1, short); + top = 0; + + R = relation; + + for (i = 0; i < ngotos; i++) + INDEX[i] = 0; + + for (i = 0; i < ngotos; i++) + { + if (INDEX[i] == 0 && R[i]) + traverse (i); + } + + FREE (INDEX); + FREE (VERTICES); +} + +static void +set_state_table (void) +{ + core *sp; + + state_table = NEW2 (nstates, core *); + + for (sp = first_state; sp; sp = sp->next) + state_table[sp->number] = sp; +} + + +static void +set_accessing_symbol (void) +{ + core *sp; + + accessing_symbol = NEW2 (nstates, short); + + for (sp = first_state; sp; sp = sp->next) + accessing_symbol[sp->number] = sp->accessing_symbol; +} + + +static void +set_shift_table (void) +{ + shifts *sp; + + shift_table = NEW2 (nstates, shifts *); + + for (sp = first_shift; sp; sp = sp->next) + shift_table[sp->number] = sp; +} + + +static void +set_reduction_table (void) +{ + reductions *rp; + + reduction_table = NEW2 (nstates, reductions *); + + for (rp = first_reduction; rp; rp = rp->next) + reduction_table[rp->number] = rp; +} + + +static void +set_maxrhs (void) +{ + short *itemp; + int length; + int max; + + length = 0; + max = 0; + for (itemp = ritem; *itemp; itemp++) + { + if (*itemp > 0) + { + length++; + } + else + { + if (length > max) + max = length; + length = 0; + } + } + + maxrhs = max; +} + + +static void +initialize_LA (void) +{ + int i; + int j; + int count; + reductions *rp; + shifts *sp; + short *np; + + consistent = NEW2 (nstates, char); + lookaheads = NEW2 (nstates + 1, short); + + count = 0; + for (i = 0; i < nstates; i++) + { + 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]])))) + 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; + } + } + } + + lookaheads[nstates] = count; + + if (count == 0) + { + LA = NEW2 (1 * tokensetsize, unsigned); + LAruleno = NEW2 (1, short); + lookback = NEW2 (1, shorts *); + } + else + { + LA = NEW2 (count * tokensetsize, unsigned); + LAruleno = NEW2 (count, short); + lookback = NEW2 (count, shorts *); + } + + np = LAruleno; + for (i = 0; i < nstates; i++) + { + if (!consistent[i]) + { + if ((rp = reduction_table[i])) + for (j = 0; j < rp->nreds; j++) + *np++ = rp->rules[j]; + } + } +} + + +static void +set_goto_map (void) +{ + 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; + + ngotos = 0; + for (sp = first_shift; sp; sp = sp->next) + { + for (i = sp->nshifts - 1; i >= 0; i--) + { + symbol = accessing_symbol[sp->shifts[i]]; + + if (ISTOKEN (symbol)) + break; + + if (ngotos == MAXSHORT) + fatal (_("too many gotos (max %d)"), MAXSHORT); + + ngotos++; + goto_map[symbol]++; + } + } + + k = 0; + for (i = ntokens; i < nsyms; i++) + { + temp_map[i] = k; + k += goto_map[i]; + } + + for (i = ntokens; i < nsyms; i++) + goto_map[i] = temp_map[i]; + + goto_map[nsyms] = ngotos; + temp_map[nsyms] = ngotos; + + from_state = NEW2 (ngotos, short); + to_state = NEW2 (ngotos, short); + + for (sp = first_shift; sp; sp = sp->next) + { + state1 = sp->number; + for (i = sp->nshifts - 1; i >= 0; i--) + { + state2 = sp->shifts[i]; + symbol = accessing_symbol[state2]; + + if (ISTOKEN (symbol)) + break; + + k = temp_map[symbol]++; + from_state[k] = state1; + to_state[k] = state2; + } + } + + FREE (temp_map + ntokens); +} + + + +/* Map_goto maps a state/symbol pair into its numeric representation. */ + +static int +map_goto (int state, int symbol) +{ + int high; + int low; + int middle; + int s; + + low = goto_map[symbol]; + high = goto_map[symbol + 1] - 1; + + while (low <= high) + { + middle = (low + high) / 2; + s = from_state[middle]; + if (s == state) + return middle; + else if (s < state) + low = middle + 1; + else + high = middle - 1; + } + + berror ("map_goto"); +/* NOTREACHED */ + return 0; +} + + +static void +initialize_F (void) +{ + 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); + + reads = NEW2 (ngotos, short *); + edge = NEW2 (ngotos + 1, short); + nedges = 0; + + rowp = F; + for (i = 0; i < ngotos; i++) + { + stateno = to_state[i]; + sp = shift_table[stateno]; + + if (sp) + { + k = sp->nshifts; + + for (j = 0; j < k; j++) + { + symbol = accessing_symbol[sp->shifts[j]]; + if (ISVAR (symbol)) + break; + SETBIT (rowp, symbol); + } + + for (; j < k; j++) + { + symbol = accessing_symbol[sp->shifts[j]]; + if (nullable[symbol]) + edge[nedges++] = map_goto (stateno, symbol); + } + + if (nedges) + { + reads[i] = rp = NEW2 (nedges + 1, short); + + for (j = 0; j < nedges; j++) + rp[j] = edge[j]; + + rp[nedges] = -1; + nedges = 0; + } + } + + rowp += tokensetsize; + } + + digraph (reads); + + for (i = 0; i < ngotos; i++) + { + if (reads[i]) + FREE (reads[i]); + } + + FREE (reads); + FREE (edge); +} + + +static void +add_lookback_edge (int stateno, int ruleno, int gotono) +{ + int i; + int k; + int found; + shorts *sp; + + i = lookaheads[stateno]; + k = lookaheads[stateno + 1]; + found = 0; + while (!found && i < k) + { + if (LAruleno[i] == ruleno) + found = 1; + else + i++; + } + + if (found == 0) + berror ("add_lookback_edge"); + + sp = NEW (shorts); + sp->next = lookback[i]; + sp->value = gotono; + lookback[i] = sp; +} + + +static short ** +transpose (short **R_arg, int n) +{ + short **new_R; + short **temp_R; + short *nedges; + short *sp; + int i; + int k; + + nedges = NEW2 (n, short); + + for (i = 0; i < n; i++) + { + sp = R_arg[i]; + if (sp) + { + while (*sp >= 0) + nedges[*sp++]++; + } + } + + new_R = NEW2 (n, short *); + temp_R = NEW2 (n, short *); + + for (i = 0; i < n; i++) + { + k = nedges[i]; + if (k > 0) + { + sp = NEW2 (k + 1, short); + new_R[i] = sp; + temp_R[i] = sp; + sp[k] = -1; + } + } + + FREE (nedges); + + for (i = 0; i < n; i++) + { + sp = R_arg[i]; + if (sp) + { + while (*sp >= 0) + *temp_R[*sp++]++ = i; + } + } + + FREE (temp_R); + + return new_R; +} + + +static void +build_relations (void) +{ + 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 = 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); +} + + + +static void +compute_FOLLOWS (void) +{ + int i; + + digraph (includes); + + for (i = 0; i < ngotos; i++) + { + if (includes[i]) + FREE (includes[i]); + } + + FREE (includes); +} + + +static void +compute_lookaheads (void) +{ + int i; + int n; + unsigned *fp1; + unsigned *fp2; + unsigned *fp3; + shorts *sp; + unsigned *rowp; + shorts *sptmp; /* JF */ + + 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++; + } + + rowp = fp3; + } + + for (i = 0; i < n; i++) + { + /* JF removed ref to freed storage */ + for (sp = lookback[i]; sp; sp = sptmp) + { + sptmp = sp->next; + FREE (sp); + } + } + + FREE (lookback); + FREE (F); +} + + +void +lalr (void) +{ + 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 (); +} diff --git a/src/lalr.h b/src/lalr.h new file mode 100644 index 00000000..4f11cc51 --- /dev/null +++ b/src/lalr.h @@ -0,0 +1,80 @@ +/* Compute look-ahead criteria for bison, + Copyright (C) 1984, 1986, 1989 Free Software Foundation, Inc. + + 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 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, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#ifndef LALR_H_ +# define LALR_H_ + +/* Compute how to make the finite state machine deterministic; find + which rules need lookahead in each state, and which lookahead + tokens they accept. */ + +void lalr PARAMS ((void)); + + +/* lalr() builds these data structures. */ + +/* goto_map, from_state and to_state --record each shift transition + which accepts a variable (a nonterminal). + + 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. */ + +extern short *goto_map; +extern short *from_state; +extern short *to_state; + +/* CONSISTENT[S] is nonzero if no lookahead is needed to decide what + to do in state S. */ + +extern char *consistent; + + +/* 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. + */ + +extern short *LAruleno; + +/* 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. */ + +extern unsigned *LA; + + +extern int tokensetsize; +extern short *lookaheads; +extern short *accessing_symbol; +extern core **state_table; +extern shifts **shift_table; +extern reductions **reduction_table; + + + +#endif /* !LALR_H_ */ diff --git a/src/output.c b/src/output.c index 56538f0c..1d1dbd2f 100644 --- a/src/output.c +++ b/src/output.c @@ -98,25 +98,14 @@ #include "state.h" #include "complain.h" #include "output.h" +#include "lalr.h" extern void berror PARAMS((const char *)); extern char **tags; extern short *user_toknums; -extern int tokensetsize; extern int final_state; -extern core **state_table; -extern shifts **shift_table; extern errs **err_table; -extern reductions **reduction_table; -extern short *accessing_symbol; -extern unsigned *LA; -extern short *LAruleno; -extern short *lookaheads; -extern char *consistent; -extern short *goto_map; -extern short *from_state; -extern short *to_state; extern void reader_output_yylsp PARAMS ((FILE *)); diff --git a/src/print.c b/src/print.c index 373c5ffc..8e10e4cf 100644 --- a/src/print.c +++ b/src/print.c @@ -24,16 +24,11 @@ #include "files.h" #include "gram.h" #include "state.h" - +#include "lalr.h" extern char **tags; extern int nstates; -extern short *accessing_symbol; -extern core **state_table; -extern shifts **shift_table; extern errs **err_table; -extern reductions **reduction_table; -extern char *consistent; extern char any_conflicts; extern char *conflicts; extern int final_state;