Merge pull request #94 from pesco/fix-49-stringmap-segfault

Fix #49 stringmap segfault

src/backends/llk.c

@@ -81,7 +81,6 @@ static void *combine_entries(HHashSet *workset, void *dst, const void *src)
 
 // add the mappings of src to dst, marking conflicts and adding the conflicting
 // values to workset.
-// note: reuses parts of src to build dst!
 static void stringmap_merge(HHashSet *workset, HStringMap *dst, HStringMap *src)
 {
   if(src->epsilon_branch) {
@@ -118,13 +117,16 @@ static void stringmap_merge(HHashSet *workset, HStringMap *dst, HStringMap *src)
 
       if(src_) {
         HStringMap *dst_ = h_hashtable_get(dst->char_branches, (void *)c);
-        if(dst_)
+        if(dst_) {
           stringmap_merge(workset, dst_, src_);
-        else
+        } else {
+          if(src_->arena != dst->arena)
+            src_ = h_stringmap_copy(dst->arena, src_);
           h_hashtable_put(dst->char_branches, (void *)c, src_);
         }
       }
     }
+  }
 }
 
 /* Generate entries for the productions of A in the given table row. */

src/cfgrammar.c

@@ -281,6 +281,13 @@ void h_stringmap_update(HStringMap *m, const HStringMap *n)
   h_hashtable_merge(combine_stringmap, m->char_branches, n->char_branches);
 }
 
+HStringMap *h_stringmap_copy(HArena *a, const HStringMap *m)
+{
+  HStringMap *res = h_stringmap_new(a);
+  h_stringmap_update(res, m);
+  return res;
+}
+
 /* Replace all occurances of old in m with new.
  * If old is NULL, replace all values in m with new.
  * If new is NULL, remove the respective values.

src/cfgrammar.h

@@ -40,6 +40,7 @@ typedef struct HStringMap_ {
 } HStringMap;
 
 HStringMap *h_stringmap_new(HArena *a);
+HStringMap *h_stringmap_copy(HArena *a, const HStringMap *m);
 void h_stringmap_put_end(HStringMap *m, void *v);
 void h_stringmap_put_epsilon(HStringMap *m, void *v);
 void h_stringmap_put_after(HStringMap *m, uint8_t c, HStringMap *ends);