Update doxygen and fix documentation (#5106)

Update Doxyfile to version 1.9.1

Re-enable doxygen CI checker

Fix some regular comments that should have been doc comments

Document void return types for some inline functions explicitly

Move start of some doxygen groups so they are included always, and not left
out of certain ifdefs

Ignore some doxygen warnings:
    Member (function) is not documented in headers
    Documented empty return type in headers
    Argument has multiple @param documentation sections

JerryScript-DCO-1.0-Signed-off-by: Máté Tokodi mate.tokodi@szteszoftver.hu

jerry-core/jmem/jmem-heap.c

@@ -48,7 +48,14 @@
 #define JMEM_HEAP_GET_OFFSET_FROM_ADDR(p) ((uint32_t) (p))
 #define JMEM_HEAP_GET_ADDR_FROM_OFFSET(u) ((jmem_heap_free_t *) (u))
 #else /* !ECMA_VALUE_CAN_STORE_UINTPTR_VALUE_DIRECTLY */
+/**
+ * Get heap offset from address
+ */
 #define JMEM_HEAP_GET_OFFSET_FROM_ADDR(p) ((uint32_t) ((uint8_t *) (p) -JERRY_HEAP_CONTEXT (area)))
+
+/**
+ * Get heap address from offset
+ */
 #define JMEM_HEAP_GET_ADDR_FROM_OFFSET(u) ((jmem_heap_free_t *) (JERRY_HEAP_CONTEXT (area) + (u)))
 #endif /* ECMA_VALUE_CAN_STORE_UINTPTR_VALUE_DIRECTLY */
 /**
@@ -302,6 +309,9 @@ jmem_heap_gc_and_alloc_block (const size_t size, /**< required memory size */
 
 /**
  * Internal method for allocating a memory block.
+ *
+ * @return NULL, if the required memory size is 0 or not enough memory, or
+ *         pointer to the allocated memory block, if allocation is successful
  */
 extern inline void *JERRY_ATTR_HOT JERRY_ATTR_ALWAYS_INLINE
 jmem_heap_alloc_block_internal (const size_t size) /**< required memory size */
@@ -449,10 +459,12 @@ jmem_heap_insert_block (jmem_heap_free_t *block_p, /**< block to insert */
 
 /**
  * Internal method for freeing a memory block.
+ *
+ * @return void
  */
 void JERRY_ATTR_HOT
 jmem_heap_free_block_internal (void *ptr, /**< pointer to beginning of data space of the block */
-                               const size_t size) /**< size of allocated region */
+                               const size_t size /**< size of allocated region */)
 {
   JERRY_ASSERT (size > 0);
   JERRY_ASSERT (JERRY_CONTEXT (jmem_heap_limit) >= JERRY_CONTEXT (jmem_heap_allocated_size));
@@ -683,6 +695,8 @@ jmem_heap_realloc_block (void *ptr, /**< memory region to reallocate */
 
 /**
  * Free memory block
+ *
+ * @return void
  */
 extern inline void JERRY_ATTR_HOT JERRY_ATTR_ALWAYS_INLINE
 jmem_heap_free_block (void *ptr, /**< pointer to beginning of data space of the block */

jerry-core/jmem/jmem-poolman.c

@@ -114,6 +114,8 @@ jmem_pools_alloc (size_t size) /**< size of the chunk */
 
 /**
  * Free the chunk
+ *
+ * @return void
  */
 extern inline void JERRY_ATTR_HOT JERRY_ATTR_ALWAYS_INLINE
 jmem_pools_free (void *chunk_p, /**< pointer to the chunk */