diff --git a/jerry-core/ecma/base/ecma-gc.c b/jerry-core/ecma/base/ecma-gc.c
index a28006621214fe3050499fa4dd5855f60c1dc508..f79d18a69cf007916bf1e194e38cc5ac9476afdc 100755
--- a/jerry-core/ecma/base/ecma-gc.c
+++ b/jerry-core/ecma/base/ecma-gc.c
@@ -1343,13 +1343,13 @@ ecma_gc_free_object (ecma_object_t *object_p) /**< object to free */
 } /* ecma_gc_free_object */
 
 bool g_isGCEnabled = true;
-void EnableGC()
+void EnableGC(void)
 {
   g_isGCEnabled = true;
   ecma_gc_run();
 }
 
-void DisableGC()
+void DisableGC(void)
 {
   g_isGCEnabled = false;
 }
diff --git a/jerry-core/ecma/base/ecma-gc.h b/jerry-core/ecma/base/ecma-gc.h
index a10e023fb3e326cc25a070d5167f9ccaeeaccd54..dfc40da885a4d42fc18b09ac26780fb57be76cd8 100644
--- a/jerry-core/ecma/base/ecma-gc.h
+++ b/jerry-core/ecma/base/ecma-gc.h
@@ -33,6 +33,8 @@ void ecma_gc_free_properties (ecma_object_t *object_p);
 void ecma_gc_run (void);
 void ecma_free_unused_memory (jmem_pressure_t pressure);
 
+void EnableGC(void);
+void DisableGC(void);
 /**
  * @}
  * @}
diff --git a/jerry-core/ecma/base/ecma-literal-storage.c b/jerry-core/ecma/base/ecma-literal-storage.c
index 15373c849d085605dae56fc828e64f392bcf7489..4464a327ce43d1c2ee794ac5b7ea2ba950732579 100755
--- a/jerry-core/ecma/base/ecma-literal-storage.c
+++ b/jerry-core/ecma/base/ecma-literal-storage.c
@@ -23,11 +23,11 @@ void InitJerryLiteralCache(void) {}
 
 void ClearJerryLiteralCache(void) {}
 
-void AddJerryLiteralCache(int32_t hash, void *p) {}
+void AddJerryLiteralCache(int32_t __attribute__((unused)) hash, void __attribute__((unused)) *p) {}
 
-void DelJerryLiteralCache(int32_t hash) {}
+void DelJerryLiteralCache(int32_t __attribute__((unused)) hash) {}
 
-void *GetJerryLiteralCache(int32_t hash)
+void *GetJerryLiteralCache(int32_t __attribute__((unused)) hash)
 {
   return (void*)UINT32_MAX;
 }
@@ -87,7 +87,7 @@ ecma_free_string_list (jmem_cpointer_t string_list_cp) /**< string list */
                                                                 string_list_p->values[i]);
 
         JERRY_ASSERT (ECMA_STRING_IS_REF_EQUALS_TO_ONE (string_p));
-        DelJerryLiteralCache(string_p->u.hash);
+        DelJerryLiteralCache((int32_t)(uint32_t)string_p->u.hash);
         ecma_destroy_ecma_string (string_p);
       }
     }
@@ -153,7 +153,7 @@ ecma_find_or_create_literal_string (const lit_utf8_byte_t *chars_p, /**< string
   }
 
   ecma_string_t *nonref_string_p = ecma_new_nonref_ecma_string_from_utf8(chars_p, size);
-  ecma_string_t *cached_literal = (ecma_string_t *)GetJerryLiteralCache(nonref_string_p->u.hash);
+  ecma_string_t *cached_literal = (ecma_string_t *)GetJerryLiteralCache((int32_t)(uint32_t)nonref_string_p->u.hash);
   if ((cached_literal != NULL) && (cached_literal != (void*)UINT32_MAX)) {
     if (ecma_compare_ecma_strings_with_literal (nonref_string_p, cached_literal,chars_p)) {
        return ecma_make_string_value (cached_literal);
@@ -209,7 +209,7 @@ ecma_find_or_create_literal_string (const lit_utf8_byte_t *chars_p, /**< string
   if (empty_cpointer_p != NULL)
   {
     *empty_cpointer_p = result;
-    AddJerryLiteralCache(string_p->u.hash, string_p);
+    AddJerryLiteralCache((int32_t)(uint32_t)string_p->u.hash, string_p);
     return ecma_make_string_value (string_p);
   }
 
@@ -225,7 +225,7 @@ ecma_find_or_create_literal_string (const lit_utf8_byte_t *chars_p, /**< string
   new_item_p->next_cp = JERRY_CONTEXT (string_list_first_cp);
   JMEM_CP_SET_NON_NULL_POINTER (JERRY_CONTEXT (string_list_first_cp), new_item_p);
 
-  AddJerryLiteralCache(string_p->u.hash, string_p);
+  AddJerryLiteralCache((int32_t)(uint32_t)string_p->u.hash, string_p);
   return ecma_make_string_value (string_p);
 } /* ecma_find_or_create_literal_string */
 
diff --git a/jerry-core/jmem/jmem-heap.c b/jerry-core/jmem/jmem-heap.c
index d0fe71e1a76083e34a565daeb58f80d3a59a6e95..322d738ff90df425cb14d028cc368588ab2a2d4f 100755
--- a/jerry-core/jmem/jmem-heap.c
+++ b/jerry-core/jmem/jmem-heap.c
@@ -23,16 +23,16 @@
 #include "jrt-bit-fields.h"
 #include "jrt-libc-includes.h"
 
-void *JerryHeapMalloc(uint32_t size)
+void *JerryHeapMalloc(uint32_t __attribute__((unused)) size)
 {
    return NULL;
 }
-bool JerryHeapFree(void *addr)
+bool JerryHeapFree(void __attribute__((unused)) *addr)
 {
    return false;
 }
 
-void JerryHeapInit() {}
+void JerryHeapInit(void) {}
 
 #define JMEM_ALLOCATOR_INTERNAL
 #include "jmem-allocator-internal.h"
@@ -147,7 +147,7 @@ static void * JERRY_ATTR_HOT
 jmem_heap_alloc (const size_t size) /**< size of requested block */
 {
   if (size > 8 && size <= 24) {
-   void *data_space_p = JerryHeapMalloc (size);
+   void *data_space_p = JerryHeapMalloc ((uint32_t)size);
    if (data_space_p != NULL)
    {
      JERRY_CONTEXT (jmem_heap_allocated_size) += size;
diff --git a/jerry-core/jmem/jmem.h b/jerry-core/jmem/jmem.h
index a89f705df454ead5fff5c00a3f2db583175cfc2a..0ea6a03d0b91a1e105af58a920ed23abc8342c30 100644
--- a/jerry-core/jmem/jmem.h
+++ b/jerry-core/jmem/jmem.h
@@ -307,6 +307,9 @@ void *jmem_pools_alloc (size_t size);
 void jmem_pools_free (void *chunk_p, size_t size);
 void jmem_pools_collect_empty (void);
 
+void *JerryHeapMalloc(uint32_t __attribute__((unused)) size);
+bool JerryHeapFree(void __attribute__((unused)) *addr);
+void JerryHeapInit(void);
 /**
  * @}
  * @}