Returning NULL from mem_heap_alloc_block if requested block size is zero.

src/liballocator/mem-heap.c

@@ -409,8 +409,8 @@ mem_init_block_header (uint8_t *first_chunk_p,         /**< address of the first
  * It is supposed, that all short-term allocation is used during relatively short discrete sessions.
  * After end of the session all short-term allocated regions are supposed to be freed.
  *
- * @return pointer to allocated memory block - if allocation is successful,\n
+ * @return pointer to allocated memory block - if allocation is successful,
- *         NULL - if there is not enough memory.
+ *         NULL - if requested region size is zero or if there is not enough memory.
  */
 void*
 mem_heap_alloc_block (size_t size_in_bytes,           /**< size of region to allocate in bytes */
@@ -421,6 +421,11 @@ mem_heap_alloc_block (size_t size_in_bytes,           /**< size of region to all
 
   mem_check_heap ();
 
+  if (size_in_bytes == 0)
+  {
+    return NULL;
+  }
+
   if (alloc_term == MEM_HEAP_ALLOC_LONG_TERM)
   {
     block_p = mem_heap.first_block_p;

src/liballocator/mem-heap.h

@@ -88,14 +88,14 @@ extern void mem_heap_stats_reset_peak (void);
  */
 #define MEM_DEFINE_LOCAL_ARRAY(var_name, number, type) \
 { \
-  type *var_name = ((number > 0) \
+  size_t var_name ## ___size = (size_t) (number) * sizeof (type); \
-                    ? mem_heap_alloc_block ((number) * sizeof (type), MEM_HEAP_ALLOC_SHORT_TERM) \
+  type *var_name = mem_heap_alloc_block (var_name ## ___size, MEM_HEAP_ALLOC_SHORT_TERM); \
-                    : NULL); \
   \
-  if (var_name == NULL) \
+  if (number > 0 \
+      && var_name == NULL) \
   { \
     jerry_exit (ERR_OUT_OF_MEMORY); \
-  } \
+  }
 
 /**
  * Free the previously defined local array variable, freeing corresponding block on the heap,
@@ -104,8 +104,14 @@ extern void mem_heap_stats_reset_peak (void);
 #define MEM_FINALIZE_LOCAL_ARRAY(var_name) \
   if (var_name != NULL) \
   { \
+    JERRY_ASSERT (var_name ## ___size != 0); \
+    \
     mem_heap_free_block (var_name); \
   } \
+  else \
+  { \
+    JERRY_ASSERT (var_name ## ___size == 0); \
+  } \
 }
 
 /**