[CN-Exec] Add zalloc for hashtable

It expects zeroed memory

runtime/libcn/include/cn-executable/alloc.h

@@ -21,6 +21,11 @@ void *alloc_(long nbytes, const char *, int);
 #define alloc(x)\
  alloc_(x, __FILE__, __LINE__)
 
+void *zalloc_(long nbytes, const char *, int);
+
+#define zalloc(x)\
+ zalloc_(x, __FILE__, __LINE__)
+
 void free_all(void);
 
 // void *alloc_zeros(long nbytes);

runtime/libcn/src/alloc.c

@@ -53,6 +53,12 @@ void *alloc_(long nbytes, const char *str, int line) {
  //return malloc(nbytes);
 }
 
+void *zalloc_(long nbytes, const char *str, int line) {
+ void *p = alloc_(nbytes, str, line);
+ memset(p, 0, nbytes);
+ return p;
+}
+
 void free_all(void) {
  curr = buf;
 }

runtime/libcn/src/hash_table.c

@@ -43,7 +43,7 @@ hash_table* ht_create(void) {
  table->capacity = INITIAL_CAPACITY;
 
  // Allocate (zero'd) space for entry buckets.
- table->entries = alloc(table->capacity * sizeof(ht_entry));
+ table->entries = zalloc(table->capacity * sizeof(ht_entry));
  if (table->entries == NULL) {
  // free(table); // error, free table before we return!
  return NULL;
@@ -148,7 +148,7 @@ static _Bool ht_expand(hash_table* table) {
  if (new_capacity < table->capacity) {
  return 0; // overflow (capacity would be too big)
  }
- ht_entry* new_entries = alloc(new_capacity * sizeof(ht_entry));
+ ht_entry* new_entries = zalloc(new_capacity * sizeof(ht_entry));
  if (new_entries == NULL) {
  return 0;
  }