Added tool bison++-1.21.11

1 files changed, 761 insertions, 0 deletions

diff --git a/tools/bison++/lalr.cc b/tools/bison++/lalr.cc
new file mode 100644
index 000000000..f79f16d98
--- /dev/null
+++ b/tools/bison++/lalr.cc
@@ -0,0 +1,761 @@
+/* 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, 675 Mass Ave, Cambridge, MA 02139, 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.
+*/
+
+#include <stdio.h>
+#include "system.h"
+#include "machine.h"
+#include "types.h"
+#include "state.h"
+#include "new.h"
+#include "gram.h"
+
+
+extern short **derives;
+extern char *nullable;
+
+
+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;
+
+short **transpose(short**,int);
+void set_state_table();
+void set_accessing_symbol();
+void set_shift_table();
+void set_reduction_table();
+void set_maxrhs();
+void initialize_LA();
+void set_goto_map();
+void initialize_F();
+void build_relations();
+void add_lookback_edge(int,int,int);
+void compute_FOLLOWS();
+void compute_lookaheads();
+void digraph(short**);
+void traverse(int);
+
+extern void toomany(char*);
+extern void berror(char*);
+
+static int infinity;
+static int maxrhs;
+static int ngotos;
+static unsigned *F;
+static short **includes;
+static shorts **lookback;
+static short **R;
+static short *INDEX;
+static short *VERTICES;
+static int top;
+
+
+void
+lalr()
+{
+  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();
+}
+
+
+void
+set_state_table()
+{
+  register core *sp;
+
+  state_table = NEW2(nstates, core *);
+
+  for (sp = first_state; sp; sp = sp->next)
+    state_table[sp->number] = sp;
+}
+
+
+void
+set_accessing_symbol()
+{
+  register core *sp;
+
+  accessing_symbol = NEW2(nstates, short);
+
+  for (sp = first_state; sp; sp = sp->next)
+    accessing_symbol[sp->number] = sp->accessing_symbol;
+}
+
+
+void
+set_shift_table()
+{
+  register shifts *sp;
+
+  shift_table = NEW2(nstates, shifts *);
+
+  for (sp = first_shift; sp; sp = sp->next)
+    shift_table[sp->number] = sp;
+}
+
+
+void
+set_reduction_table()
+{
+  register reductions *rp;
+
+  reduction_table = NEW2(nstates, reductions *);
+
+  for (rp = first_reduction; rp; rp = rp->next)
+    reduction_table[rp->number] = rp;
+}
+
+
+void
+set_maxrhs()
+{
+  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;
+}
+
+
+void
+initialize_LA()
+{
+  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->internalShifts[0]]))))
+	count += rp->nreds;
+      else
+	consistent[i] = 1;
+
+      if (sp)
+	for (k = 0; k < sp->nshifts; k++)
+	  {
+	    if (accessing_symbol[sp->internalShifts[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];
+	}
+    }
+}
+
+
+void
+set_goto_map()
+{
+  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->internalShifts[i]];
+
+	  if (ISTOKEN(symbol)) break;
+
+	  if (ngotos == MAXSHORT)
+	    toomany("gotos");
+
+	  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->internalShifts[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.	*/
+
+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;
+}
+
+
+void
+initialize_F()
+{
+  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->internalShifts[j]];
+	      if (ISVAR(symbol))
+		break;
+	      SETBIT(rowp, symbol);
+	    }
+
+	  for (; j < k; j++)
+	    {
+	      symbol = accessing_symbol[sp->internalShifts[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);
+}
+
+
+void
+build_relations()
+{
+  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->internalShifts[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
+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;
+}
+
+
+
+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);
+}
+
+
+void
+compute_FOLLOWS()
+{
+  register int i;
+
+  digraph(includes);
+
+  for (i = 0; i < ngotos; i++)
+    {
+      if (includes[i]) FREE(includes[i]);
+    }
+
+  FREE(includes);
+}
+
+
+void
+compute_lookaheads()
+{
+  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);
+}
+
+
+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);
+}
+
+
+void
+traverse(int i)
+{
+  register unsigned *fp1;
+  register unsigned *fp2;
+  register unsigned *fp3;
+  register int j;
+  register 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++;
+	}
+    }
+}