1 files changed, 32 insertions, 25 deletions

diff --git a/tool/lemon.c b/tool/lemon.c
index edf17cae7..d4e157a1c 100644
--- a/tool/lemon.c
+++ b/tool/lemon.c
@@ -917,8 +917,11 @@ void FindStates(struct lemon *lemp)
       lemp->errorcnt++;
       sp = lemp->startRule->lhs;
     }
-  }else{
+  }else if( lemp->startRule ){
     sp = lemp->startRule->lhs;
+  }else{
+    ErrorMsg(lemp->filename,0,"Internal error - no start rule\n");
+    exit(1);
   }
 
   /* Make sure the start symbol doesn't occur on the right-hand side of
@@ -1083,7 +1086,7 @@ void FindLinks(struct lemon *lemp)
   ** which the link is attached. */
   for(i=0; i<lemp->nstate; i++){
     stp = lemp->sorted[i];
-    for(cfp=stp->cfp; cfp; cfp=cfp->next){
+    for(cfp=stp?stp->cfp:0; cfp; cfp=cfp->next){
       cfp->stp = stp;
     }
   }
@@ -1092,7 +1095,7 @@ void FindLinks(struct lemon *lemp)
   ** links are used in the follow-set computation. */
   for(i=0; i<lemp->nstate; i++){
     stp = lemp->sorted[i];
-    for(cfp=stp->cfp; cfp; cfp=cfp->next){
+    for(cfp=stp?stp->cfp:0; cfp; cfp=cfp->next){
       for(plp=cfp->bplp; plp; plp=plp->next){
         other = plp->cfp;
         Plink_add(&other->fplp,cfp);
@@ -1115,6 +1118,7 @@ void FindFollowSets(struct lemon *lemp)
   int change;
 
   for(i=0; i<lemp->nstate; i++){
+    assert( lemp->sorted[i]!=0 );
     for(cfp=lemp->sorted[i]->cfp; cfp; cfp=cfp->next){
       cfp->status = INCOMPLETE;
     }
@@ -1123,6 +1127,7 @@ void FindFollowSets(struct lemon *lemp)
   do{
     progress = 0;
     for(i=0; i<lemp->nstate; i++){
+      assert( lemp->sorted[i]!=0 );
       for(cfp=lemp->sorted[i]->cfp; cfp; cfp=cfp->next){
         if( cfp->status==COMPLETE ) continue;
         for(plp=cfp->fplp; plp; plp=plp->next){
@@ -1172,7 +1177,14 @@ void FindActions(struct lemon *lemp)
   /* Add the accepting token */
   if( lemp->start ){
     sp = Symbol_find(lemp->start);
-    if( sp==0 ) sp = lemp->startRule->lhs;
+    if( sp==0 ){
+      if( lemp->startRule==0 ){
+        fprintf(stderr, "internal error on source line %d: no start rule\n",
+                __LINE__);
+        exit(1);
+      }
+      sp = lemp->startRule->lhs;
+    }
   }else{
     sp = lemp->startRule->lhs;
   }
@@ -1299,21 +1311,7 @@ static struct config **basisend = 0;     /* End of list of basis configs */
 
 /* Return a pointer to a new configuration */
 PRIVATE struct config *newconfig(void){
-  struct config *newcfg;
-  if( freelist==0 ){
-    int i;
-    int amt = 3;
-    freelist = (struct config *)calloc( amt, sizeof(struct config) );
-    if( freelist==0 ){
-      fprintf(stderr,"Unable to allocate memory for a new configuration.");
-      exit(1);
-    }
-    for(i=0; i<amt-1; i++) freelist[i].next = &freelist[i+1];
-    freelist[amt-1].next = 0;
-  }
-  newcfg = freelist;
-  freelist = freelist->next;
-  return newcfg;
+  return (struct config*)calloc(1, sizeof(struct config));
 }
 
 /* The configuration "old" is no longer used */
@@ -1932,8 +1930,12 @@ static FILE *errstream;
 static void errline(int n, int k, FILE *err)
 {
   int spcnt, i;
-  if( g_argv[0] ) fprintf(err,"%s",g_argv[0]);
-  spcnt = lemonStrlen(g_argv[0]) + 1;
+  if( g_argv[0] ){
+    fprintf(err,"%s",g_argv[0]);
+    spcnt = lemonStrlen(g_argv[0]) + 1;
+  }else{
+    spcnt = 0;
+  }
   for(i=1; i<n && g_argv[i]; i++){
     fprintf(err," %s",g_argv[i]);
     spcnt += lemonStrlen(g_argv[i])+1;
@@ -4092,7 +4094,7 @@ void print_stack_union(
   int *plineno,               /* Pointer to the line number */
   int mhflag                  /* True if generating makeheaders output */
 ){
-  int lineno = *plineno;    /* The line number of the output */
+  int lineno;               /* The line number of the output */
   char **types;             /* A hash table of datatypes */
   int arraysize;            /* Size of the "types" array */
   int maxdtlength;          /* Maximum length of any ".datatype" field. */
@@ -5339,7 +5341,8 @@ int Strsafe_insert(const char *data)
       newnp->from = &(array.ht[h]);
       array.ht[h] = newnp;
     }
-    free(x1a->tbl);
+    /* free(x1a->tbl); // This program was originally for 16-bit machines.
+    ** Don't worry about freeing memory on modern platforms. */
     *x1a = array;
   }
   /* Insert the new data */
@@ -5507,7 +5510,9 @@ int Symbol_insert(struct symbol *data, const char *key)
       newnp->from = &(array.ht[h]);
       array.ht[h] = newnp;
     }
-    free(x2a->tbl);
+    /* free(x2a->tbl); // This program was originally written for 16-bit
+    ** machines.  Don't worry about freeing this trivial amount of memory
+    ** on modern platforms.  Just leak it. */
     *x2a = array;
   }
   /* Insert the new data */
@@ -5843,7 +5848,9 @@ int Configtable_insert(struct config *data)
       newnp->from = &(array.ht[h]);
       array.ht[h] = newnp;
     }
-    free(x4a->tbl);
+    /* free(x4a->tbl); // This code was originall written for 16-bit machines.
+    ** on modern machines, don't worry about freeing this trival amount of
+    ** memory. */
     *x4a = array;
   }
   /* Insert the new data */