29-fyi-simplify.patch

[Akim Demaille]

Index: ChangeLog
from  Akim Demaille  <address@hidden>

        * src/LR0.c (new_itemsets, get_state): Use more arrays and less
        pointers to clarify the code.
        (save_reductions, save_shifts): Factor common parts of alternatives.

Index: src/LR0.c
--- src/LR0.c Sun, 18 Nov 2001 00:21:17 +0100 akim
+++ src/LR0.c Sun, 18 Nov 2001 10:20:14 +0100 akim
@@ -1,5 +1,5 @@
 /* Generate the nondeterministic finite state machine for bison,
-   Copyright 1984, 1986, 1989, 2000 Free Software Foundation, Inc.
+   Copyright 1984, 1986, 1989, 2000, 2001  Free Software Foundation, Inc.

    This file is part of Bison, the GNU Compiler Compiler.

@@ -146,9 +146,6 @@
 {
   int i;
   int shiftcount;
-  short *isp;
-  short *ksp;
-  int symbol;

 #if TRACE
   fprintf (stderr, "Entering new_itemsets, state = %d\n",
@@ -160,23 +157,21 @@

   shiftcount = 0;

-  isp = itemset;
-
-  while (isp < itemsetend)
+  for (i = 0; i < itemsetend - itemset; ++i)
     {
-      i = *isp++;
-      symbol = ritem[i];
+      int symbol = ritem[itemset[i]];
       if (symbol > 0)
        {
-         ksp = kernel_end[symbol];
+         short *ksp = kernel_end[symbol];

          if (!ksp)
            {
-             shift_symbol[shiftcount++] = symbol;
+             shift_symbol[shiftcount] = symbol;
              ksp = kernel_base[symbol];
+             shiftcount++;
            }

-         *ksp++ = i + 1;
+         *ksp++ = itemset[i] + 1;
          kernel_end[symbol] = ksp;
        }
     }
@@ -216,7 +211,6 @@

   last_state->next = p;
   last_state = p;
-
   nstates++;

   return p;
@@ -226,55 +220,44 @@
 /*--------------------------------------------------------------.
 | Find the state number for the state we would get to (from the |
 | current state) by shifting symbol.  Create a new state if no  |
-| equivalent one exists already.  Used by append_states.         |
+| equivalent one exists already.  Used by append_states.        |
 `--------------------------------------------------------------*/

 static int
 get_state (int symbol)
 {
   int key;
-  short *isp1;
   short *isp2;
-  short *iend;
+  int i;
   core *sp;
-  int found;

-  int n;
+  int n = kernel_end[symbol] - kernel_base[symbol];

 #if TRACE
   fprintf (stderr, "Entering get_state, state = %d, symbol = %d\n",
           nstates, symbol);
 #endif

-  isp1 = kernel_base[symbol];
-  iend = kernel_end[symbol];
-  n = iend - isp1;
-
-  /* add up the target state's active item numbers to get a hash key */
+  /* Add up the target state's active item numbers to get a hash key.
+     */
   key = 0;
-  while (isp1 < iend)
-    key += *isp1++;
-
+  for (i = 0; i < n; ++i)
+    key += kernel_base[symbol][i];
   key = key % STATE_TABLE_SIZE;
-
   sp = state_table[key];

   if (sp)
     {
-      found = 0;
+      int found = 0;
       while (!found)
        {
          if (sp->nitems == n)
            {
+             int i;
              found = 1;
-             isp1 = kernel_base[symbol];
-             isp2 = sp->items;
-
-             while (found && isp1 < iend)
-               {
-                 if (*isp1++ != *isp2++)
-                   found = 0;
-               }
+             for (i = 0; i < n; ++i)
+               if (kernel_base[symbol][i] != sp->items[i])
+                 found = 0;
            }

          if (!found)
@@ -332,20 +315,14 @@
     }

   for (i = 0; i < nshifts; i++)
-    {
-      symbol = shift_symbol[i];
-      shiftset[i] = get_state (symbol);
-    }
+    shiftset[i] = get_state (shift_symbol[i]);
 }


 static void
 new_states (void)
 {
-  core *p;
-
-  p = CORE_ALLOC (0);
-  first_state = last_state = this_state = p;
+  first_state = last_state = this_state = CORE_ALLOC (0);
   nstates = 1;
 }

@@ -353,9 +330,7 @@
 static void
 save_shifts (void)
 {
-  shifts *p;
-
-  p = SHIFTS_ALLOC (nshifts);
+  shifts *p = SHIFTS_ALLOC (nshifts);

   p->number = this_state->number;
   p->nshifts = nshifts;
@@ -363,15 +338,10 @@
   shortcpy (p->shifts, shiftset, nshifts);

   if (last_shift)
-    {
-      last_shift->next = p;
-      last_shift = p;
-    }
+    last_shift->next = p;
   else
-    {
-      first_shift = p;
-      last_shift = p;
-    }
+    first_shift = p;
+  last_shift = p;
 }


@@ -617,15 +587,10 @@
       shortcpy (p->rules, redset, count);

       if (last_reduction)
-       {
-         last_reduction->next = p;
-         last_reduction = p;
-       }
+       last_reduction->next = p;
       else
-       {
-         first_reduction = p;
-         last_reduction = p;
-       }
+       first_reduction = p;
+      last_reduction = p;
     }
 }