From d9890d2ccb5aedbe782ea69419e361b543b98e8a Mon Sep 17 00:00:00 2001
From: Xu Jun <693788454@qq.com>
Date: Mon, 30 Mar 2020 11:06:39 +0800
Subject: [PATCH] re-org ems mem allocator source codes, update prot_wamr.md
 (#217)

---
 core/config.h                               |   5 +-
 core/iwasm/aot/aot_loader.c                 |   2 +-
 core/iwasm/common/wasm_memory.c             |  37 +--
 core/iwasm/interpreter/wasm_loader.c        |  10 +-
 core/shared/mem-alloc/ems/ems_alloc.c       | 334 ++++++++++----------
 core/shared/mem-alloc/ems/ems_gc.h          | 286 +++--------------
 core/shared/mem-alloc/ems/ems_gc_internal.h | 208 +++++-------
 core/shared/mem-alloc/ems/ems_hmu.c         |  32 +-
 core/shared/mem-alloc/ems/ems_kfc.c         |  89 ++----
 core/shared/mem-alloc/mem_alloc.c           |   6 +-
 doc/port_wamr.md                            |   8 +-
 11 files changed, 364 insertions(+), 653 deletions(-)

diff --git a/core/config.h b/core/config.h
index 30ceda3232..be9a241811 100644
--- a/core/config.h
+++ b/core/config.h
@@ -118,7 +118,10 @@ enum {
 #endif
 
 /* Heap and stack profiling */
-#define BEIHAI_ENABLE_MEMORY_PROFILING 0
+#define BH_ENABLE_MEMORY_PROFILING 0
+
+/* Heap verification */
+#define BH_ENABLE_GC_VERIFY 0
 
 /* Max app number of all modules */
 #define MAX_APP_INSTALLATIONS 3
diff --git a/core/iwasm/aot/aot_loader.c b/core/iwasm/aot/aot_loader.c
index 5ce4d2aadb..e6d72a86a0 100644
--- a/core/iwasm/aot/aot_loader.c
+++ b/core/iwasm/aot/aot_loader.c
@@ -1602,7 +1602,7 @@ load_from_sections(AOTModule *module, AOTSection *sections,
     return true;
 }
 
-#if BEIHAI_ENABLE_MEMORY_PROFILING != 0
+#if BH_ENABLE_MEMORY_PROFILING != 0
 static void aot_free(void *ptr)
 {
     wasm_runtime_free(ptr);
diff --git a/core/iwasm/common/wasm_memory.c b/core/iwasm/common/wasm_memory.c
index 9512ce0765..9032bc0c0b 100644
--- a/core/iwasm/common/wasm_memory.c
+++ b/core/iwasm/common/wasm_memory.c
@@ -7,7 +7,7 @@
 #include "bh_platform.h"
 #include "mem_alloc.h"
 
-#if BEIHAI_ENABLE_MEMORY_PROFILING != 0
+#if BH_ENABLE_MEMORY_PROFILING != 0
 
 /* Memory profile data of a function */
 typedef struct memory_profile {
@@ -30,7 +30,7 @@ static memory_profile_t *memory_profiles_list = NULL;
 
 /* Lock of the memory profile list */
 static korp_mutex profile_lock;
-#endif /* end of BEIHAI_ENABLE_MEMORY_PROFILING */
+#endif /* end of BH_ENABLE_MEMORY_PROFILING */
 
 #ifndef MALLOC_MEMORY_FROM_SYSTEM
 
@@ -58,7 +58,7 @@ wasm_memory_init_with_pool(void *mem, unsigned int bytes)
     if (_allocator) {
         memory_mode = MEMORY_MODE_POOL;
         pool_allocator = _allocator;
-#if BEIHAI_ENABLE_MEMORY_PROFILING != 0
+#if BH_ENABLE_MEMORY_PROFILING != 0
         os_mutex_init(&profile_lock);
 #endif
         global_pool_size = bytes;
@@ -78,7 +78,7 @@ wasm_memory_init_with_allocator(void *_malloc_func,
         malloc_func = _malloc_func;
         realloc_func = _realloc_func;
         free_func = _free_func;
-#if BEIHAI_ENABLE_MEMORY_PROFILING != 0
+#if BH_ENABLE_MEMORY_PROFILING != 0
         os_mutex_init(&profile_lock);
 #endif
         return true;
@@ -108,7 +108,7 @@ wasm_runtime_memory_init(mem_alloc_type_t mem_alloc_type,
 void
 wasm_runtime_memory_destroy()
 {
-#if BEIHAI_ENABLE_MEMORY_PROFILING != 0
+#if BH_ENABLE_MEMORY_PROFILING != 0
     os_mutex_destroy(&profile_lock);
 #endif
     if (memory_mode == MEMORY_MODE_POOL)
@@ -166,12 +166,21 @@ wasm_runtime_free(void *ptr)
     }
 }
 
-#if BEIHAI_ENABLE_MEMORY_PROFILING != 0
+#if BH_ENABLE_MEMORY_PROFILING != 0
+
+void
+memory_profile_print(const char *file, int line,
+                     const char *func, int alloc)
+{
+    os_printf("location:%s@%d:used:%d:contribution:%d\n",
+              func, line, memory_in_use, alloc);
+}
+
 void *
 wasm_runtime_malloc_profile(const char *file, int line,
                             const char *func, unsigned int size)
 {
-    void *p = wasm_rutime_malloc(size + 8);
+    void *p = wasm_runtime_malloc(size + 8);
 
     if (p) {
         memory_profile_t *profile;
@@ -292,15 +301,7 @@ void memory_usage_summarize()
     os_mutex_unlock(&profile_lock);
 }
 
-void
-memory_profile_print(const char *file, int line,
-                     const char *func, int alloc)
-{
-    os_printf("location:%s@%d:used:%d:contribution:%d\n",
-              func, line, memory_in_use, alloc);
-}
-
-#endif /* end of BEIHAI_ENABLE_MEMORY_PROFILING */
+#endif /* end of BH_ENABLE_MEMORY_PROFILING */
 
 #else /* else of MALLOC_MEMORY_FROM_SYSTEM */
 
@@ -324,7 +325,7 @@ wasm_runtime_free(void *ptr)
         free(ptr);
 }
 
-#if BEIHAI_ENABLE_MEMORY_PROFILING != 0
+#if BH_ENABLE_MEMORY_PROFILING != 0
 void *
 wasm_runtime_malloc_profile(const char *file, int line,
                             const char *func, unsigned int size)
@@ -366,6 +367,6 @@ wasm_runtime_free_profile(const char *file, int line,
     if (ptr)
         free(ptr);
 }
-#endif /* end of BEIHAI_ENABLE_MEMORY_PROFILING */
+#endif /* end of BH_ENABLE_MEMORY_PROFILING */
 #endif /* end of MALLOC_MEMORY_FROM_SYSTEM*/
 
diff --git a/core/iwasm/interpreter/wasm_loader.c b/core/iwasm/interpreter/wasm_loader.c
index 956a540b86..285493fb62 100644
--- a/core/iwasm/interpreter/wasm_loader.c
+++ b/core/iwasm/interpreter/wasm_loader.c
@@ -492,8 +492,12 @@ load_memory_import(const uint8 **p_buf, const uint8 *buf_end,
 {
     const uint8 *p = *p_buf, *p_end = buf_end;
     uint32 pool_size = wasm_runtime_memory_pool_size();
+#if WASM_ENABLE_APP_FRAMEWORK != 0
     uint32 max_page_count = pool_size * APP_MEMORY_MAX_GLOBAL_HEAP_PERCENT
                             / DEFAULT_NUM_BYTES_PER_PAGE;
+#else
+    uint32 max_page_count = pool_size / DEFAULT_NUM_BYTES_PER_PAGE;
+#endif
 
     read_leb_uint32(p, p_end, memory->flags);
     read_leb_uint32(p, p_end, memory->init_page_count);
@@ -539,8 +543,12 @@ load_memory(const uint8 **p_buf, const uint8 *buf_end, WASMMemory *memory,
 {
     const uint8 *p = *p_buf, *p_end = buf_end;
     uint32 pool_size = wasm_runtime_memory_pool_size();
+#if WASM_ENABLE_APP_FRAMEWORK != 0
     uint32 max_page_count = pool_size * APP_MEMORY_MAX_GLOBAL_HEAP_PERCENT
                             / DEFAULT_NUM_BYTES_PER_PAGE;
+#else
+    uint32 max_page_count = pool_size / DEFAULT_NUM_BYTES_PER_PAGE;
+#endif
 
     read_leb_uint32(p, p_end, memory->flags);
     read_leb_uint32(p, p_end, memory->init_page_count);
@@ -1694,7 +1702,7 @@ load_from_sections(WASMModule *module, WASMSection *sections,
     return true;
 }
 
-#if BEIHAI_ENABLE_MEMORY_PROFILING != 0
+#if BH_ENABLE_MEMORY_PROFILING != 0
 static void wasm_loader_free(void *ptr)
 {
     wasm_runtime_free(ptr);
diff --git a/core/shared/mem-alloc/ems/ems_alloc.c b/core/shared/mem-alloc/ems/ems_alloc.c
index ed79a37a92..45d6b585a5 100644
--- a/core/shared/mem-alloc/ems/ems_alloc.c
+++ b/core/shared/mem-alloc/ems/ems_alloc.c
@@ -6,21 +6,25 @@
 #include "ems_gc_internal.h"
 
 
-static int hmu_is_in_heap(gc_heap_t* heap, hmu_t* hmu)
+static int
+hmu_is_in_heap(gc_heap_t* heap, hmu_t* hmu)
 {
-    return heap && hmu && (gc_uint8*) hmu >= heap->base_addr
-            && (gc_uint8*) hmu < heap->base_addr + heap->current_size;
+    return heap && hmu
+           && (gc_uint8*) hmu >= heap->base_addr
+           && (gc_uint8*) hmu < heap->base_addr + heap->current_size;
 }
 
-/* Remove a node from the tree it belongs to*/
-
-/* @p can not be NULL*/
-/* @p can not be the ROOT node*/
-
-/* Node @p will be removed from the tree and left,right,parent pointers of node @p will be*/
-/*  set to be NULL. Other fields will not be touched.*/
-/* The tree will be re-organized so that the order conditions are still satisified.*/
-static void remove_tree_node(hmu_tree_node_t *p)
+/**
+ * Remove a node from the tree it belongs to
+ *
+ * @param p the node to remove, can not be NULL, can not be the ROOT node
+ *        the node will be removed from the tree, and the left, right and
+ *        parent pointers of the node @p will be set to be NULL. Other fields
+ *        won't be touched. The tree will be re-organized so that the order
+ *        conditions are still satisified.
+ */
+static void
+remove_tree_node(hmu_tree_node_t *p)
 {
     hmu_tree_node_t *q = NULL, **slot = NULL;
 
@@ -35,11 +39,14 @@ static void remove_tree_node(hmu_tree_node_t *p)
         slot = &p->parent->left;
     }
 
-    /* algorithms used to remove node p*/
-    /* case 1: if p has no left child, replace p with its right child*/
-    /* case 2: if p has no right child, replace p with its left child*/
-    /* case 3: otherwise, find p's predecessor, remove it from the tree and replace p with it.*/
-    /*         use predecessor can keep the left <= root < right condition.*/
+    /**
+     * algorithms used to remove node p
+     * case 1: if p has no left child, replace p with its right child
+     * case 2: if p has no right child, replace p with its left child
+     * case 3: otherwise, find p's predecessor, remove it from the tree
+     *         and replace p with it.
+     * use predecessor can keep the left <= root < right condition.
+     */
 
     if (!p->left) {
         /* move right child up*/
@@ -64,7 +71,8 @@ static void remove_tree_node(hmu_tree_node_t *p)
     q = p->left;
     while (q->right)
         q = q->right;
-    remove_tree_node(q); /* remove from the tree*/
+    /* remove from the tree*/
+    remove_tree_node(q);
 
     *slot = q;
     q->parent = p->parent;
@@ -78,14 +86,14 @@ static void remove_tree_node(hmu_tree_node_t *p)
     p->left = p->right = p->parent = NULL;
 }
 
-static void unlink_hmu(gc_heap_t *heap, hmu_t *hmu)
+static void
+unlink_hmu(gc_heap_t *heap, hmu_t *hmu)
 {
     gc_size_t size;
 
     bh_assert(gci_is_heap_valid(heap));
-    bh_assert(
-            hmu && (gc_uint8*) hmu >= heap->base_addr
-                    && (gc_uint8*) hmu < heap->base_addr + heap->current_size);
+    bh_assert(hmu && (gc_uint8*) hmu >= heap->base_addr
+              && (gc_uint8*) hmu < heap->base_addr + heap->current_size);
     bh_assert(hmu_get_ut(hmu) == HMU_FC);
 
     size = hmu_get_size(hmu);
@@ -105,45 +113,46 @@ static void unlink_hmu(gc_heap_t *heap, hmu_t *hmu)
         }
 
         if (!node) {
-            os_printf("[GC_ERROR]couldn't find the node in the normal list");
+            os_printf("[GC_ERROR]couldn't find the node in the normal list\n");
         }
-    } else {
+    }
+    else {
         remove_tree_node((hmu_tree_node_t *) hmu);
     }
 }
 
-static void hmu_set_free_size(hmu_t *hmu)
+static void
+hmu_set_free_size(hmu_t *hmu)
 {
     gc_size_t size;
     bh_assert(hmu && hmu_get_ut(hmu) == HMU_FC);
 
     size = hmu_get_size(hmu);
-    *((uint32*) ((char*) hmu + size) - 1) = size;
+    *((uint32*)((char*) hmu + size) - 1) = size;
 }
 
-/* Add free chunk back to KFC*/
-
-/* @heap should not be NULL and it should be a valid heap*/
-/* @hmu should not be NULL and it should be a HMU of length @size inside @heap*/
-/* @hmu should be aligned to 8*/
-/* @size should be positive and multiple of 8*/
-
-/* @hmu with size @size will be added into KFC as a new FC.*/
-void gci_add_fc(gc_heap_t *heap, hmu_t *hmu, gc_size_t size)
+/**
+ * Add free chunk back to KFC
+ *
+ * @param heap should not be NULL and it should be a valid heap
+ * @param hmu should not be NULL and it should be a HMU of length @size inside @heap
+ *        hmu should be 8-bytes aligned
+ * @param size should be positive and multiple of 8
+ *        hmu with size @size will be added into KFC as a new FC.
+ */
+void
+gci_add_fc(gc_heap_t *heap, hmu_t *hmu, gc_size_t size)
 {
     hmu_normal_node_t *np = NULL;
     hmu_tree_node_t *root = NULL, *tp = NULL, *node = NULL;
     uint32 node_idx;
 
     bh_assert(gci_is_heap_valid(heap));
-    bh_assert(
-            hmu && (gc_uint8*) hmu >= heap->base_addr
-                    && (gc_uint8*) hmu < heap->base_addr + heap->current_size);
+    bh_assert(hmu && (gc_uint8*) hmu >= heap->base_addr
+              && (gc_uint8*) hmu < heap->base_addr + heap->current_size);
     bh_assert(((gc_uint32)(uintptr_t)hmu_to_obj(hmu) & 7) == 0);
-    bh_assert(
-            size > 0
-                    && ((gc_uint8*) hmu) + size
-                            <= heap->base_addr + heap->current_size);
+    bh_assert(size > 0
+              && ((gc_uint8*) hmu) + size <= heap->base_addr + heap->current_size);
     bh_assert(!(size & 7));
 
     hmu_set_ut(hmu, HMU_FC);
@@ -154,7 +163,8 @@ void gci_add_fc(gc_heap_t *heap, hmu_t *hmu, gc_size_t size)
         np = (hmu_normal_node_t*) hmu;
 
         node_idx = size >> 3;
-        np->next = heap->kfc_normal_list[node_idx].next;
+        set_hmu_normal_node_next(np, get_hmu_normal_node_next
+                                        (&heap->kfc_normal_list[node_idx]));
         set_hmu_normal_node_next(&heap->kfc_normal_list[node_idx], np);
         return;
     }
@@ -176,8 +186,8 @@ void gci_add_fc(gc_heap_t *heap, hmu_t *hmu, gc_size_t size)
                 break;
             }
             tp = tp->right;
-        } else /* tp->size >= size*/
-        {
+        }
+        else { /* tp->size >= size*/
             if (!tp->left) {
                 tp->left = node;
                 node->parent = tp;
@@ -188,17 +198,19 @@ void gci_add_fc(gc_heap_t *heap, hmu_t *hmu, gc_size_t size)
     }
 }
 
-/* Find a proper hmu for required memory size*/
-
-/* @heap should not be NULL and it should be a valid heap*/
-/* @size should cover the header and it should be 8 bytes aligned*/
-
-/* GC will not be performed here.*/
-/* Heap extension will not be performed here.*/
-
-/* A proper HMU will be returned. This HMU can include the header and given size. The returned HMU will be aligned to 8 bytes.*/
-/* NULL will be returned if there are no proper HMU.*/
-static hmu_t *alloc_hmu(gc_heap_t *heap, gc_size_t size)
+/**
+ * Find a proper hmu for required memory size
+ *
+ * @param heap should not be NULL and should be a valid heap
+ * @param size should cover the header and should be 8 bytes aligned
+ *        GC will not be performed here.
+ *        Heap extension will not be performed here.
+ *
+ * @return hmu allocated if success, which will be aligned to 8 bytes,
+ *         NULL otherwise
+ */
+static hmu_t *
+alloc_hmu(gc_heap_t *heap, gc_size_t size)
 {
     hmu_normal_node_t *node = NULL, *p = NULL;
     uint32 node_idx = 0, init_node_idx = 0;
@@ -228,31 +240,31 @@ static hmu_t *alloc_hmu(gc_heap_t *heap, gc_size_t size)
             bh_assert(node_idx >= init_node_idx);
 
             p = get_hmu_normal_node_next(node);
-            node->next = p->next;
+            set_hmu_normal_node_next(node, get_hmu_normal_node_next(p));
             bh_assert(((gc_int32)(uintptr_t)hmu_to_obj(p) & 7) == 0);
 
             if ((gc_size_t)node_idx != (uint32)init_node_idx
-                && ((gc_size_t)node_idx << 3) >= size + GC_SMALLEST_SIZE) { /* with bigger size*/
+                /* with bigger size*/
+                && ((gc_size_t)node_idx << 3) >= size + GC_SMALLEST_SIZE) {
                 rest = (hmu_t*) (((char *) p) + size);
                 gci_add_fc(heap, rest, (node_idx << 3) - size);
                 hmu_mark_pinuse(rest);
-            } else {
+            }
+            else {
                 size = node_idx << 3;
                 next = (hmu_t*) ((char*) p + size);
                 if (hmu_is_in_heap(heap, next))
                     hmu_mark_pinuse(next);
             }
 
-#if GC_STAT_DATA != 0
             heap->total_free_size -= size;
             if ((heap->current_size - heap->total_free_size)
-                    > heap->highmark_size)
+                > heap->highmark_size)
                 heap->highmark_size = heap->current_size
-                        - heap->total_free_size;
-#endif
+                                      - heap->total_free_size;
 
-            hmu_set_size((hmu_t* ) p, size);
-            return (hmu_t*) p;
+            hmu_set_size((hmu_t* )p, size);
+            return (hmu_t*)p;
         }
     }
 
@@ -285,18 +297,18 @@ static hmu_t *alloc_hmu(gc_heap_t *heap, gc_size_t size)
             rest = (hmu_t*) ((char*) last_tp + size);
             gci_add_fc(heap, rest, last_tp->size - size);
             hmu_mark_pinuse(rest);
-        } else {
+        }
+        else {
             size = last_tp->size;
             next = (hmu_t*) ((char*) last_tp + size);
             if (hmu_is_in_heap(heap, next))
                 hmu_mark_pinuse(next);
         }
 
-#if GC_STAT_DATA != 0
         heap->total_free_size -= size;
         if ((heap->current_size - heap->total_free_size) > heap->highmark_size)
             heap->highmark_size = heap->current_size - heap->total_free_size;
-#endif
+
         hmu_set_size((hmu_t* ) last_tp, size);
         return (hmu_t*) last_tp;
     }
@@ -304,52 +316,41 @@ static hmu_t *alloc_hmu(gc_heap_t *heap, gc_size_t size)
     return NULL;
 }
 
-/* Find a proper HMU for given size*/
-
-/* @heap should not be NULL and it should be a valid heap*/
-/* @size should cover the header and it should be 8 bytes aligned*/
-
-/* This function will try several ways to satisfy the allocation request.*/
-/*  1. Find a proper on available HMUs.*/
-/*  2. GC will be triggered if 1 failed.*/
-/*  3. Find a proper on available HMUS.*/
-/*  4. Return NULL if 3 failed*/
-
-/* A proper HMU will be returned. This HMU can include the header and given size. The returned HMU will be aligned to 8 bytes.*/
-/* NULL will be returned if there are no proper HMU.*/
-static hmu_t* alloc_hmu_ex(gc_heap_t *heap, gc_size_t size)
+/**
+ * Find a proper HMU with given size
+ *
+ * @param heap should not be NULL and should be a valid heap
+ * @param size should cover the header and should be 8 bytes aligned
+ *
+ * Note: This function will try several ways to satisfy the allocation request:
+ *   1. Find a proper on available HMUs.
+ *   2. GC will be triggered if 1 failed.
+ *   3. Find a proper on available HMUS.
+ *   4. Return NULL if 3 failed
+ *
+ * @return hmu allocated if success, which will be aligned to 8 bytes,
+ *         NULL otherwise
+ */
+static hmu_t *
+alloc_hmu_ex(gc_heap_t *heap, gc_size_t size)
 {
-    hmu_t *ret = NULL;
-
     bh_assert(gci_is_heap_valid(heap));
     bh_assert(size > 0 && !(size & 7));
 
-#ifdef GC_IN_EVERY_ALLOCATION
-    gci_gc_heap(heap);
-    ret = alloc_hmu(heap, size);
-#else
-
-# if GC_STAT_DATA != 0
-    if (heap->gc_threshold < heap->total_free_size)
-        ret = alloc_hmu(heap, size);
-# else
-    ret = alloc_hmu(heap, size);
-# endif
-
-    if (ret)
-        return ret;
-
-    /*gci_gc_heap(heap);*//* disable gc claim currently */
-    ret = alloc_hmu(heap, size);
-#endif
-    return ret;
+    return alloc_hmu(heap, size);
 }
 
-unsigned long g_total_malloc = 0;
-unsigned long g_total_free = 0;
+static unsigned long g_total_malloc = 0;
+static unsigned long g_total_free = 0;
 
-gc_object_t _gc_alloc_vo_i_heap(void *vheap,
-                                gc_size_t size ALLOC_EXTRA_PARAMETERS)
+#if BH_ENABLE_GC_VERIFY == 0
+gc_object_t
+gc_alloc_vo(void *vheap, gc_size_t size)
+#else
+gc_object_t
+gc_alloc_vo_internal(void *vheap, gc_size_t size,
+                     const char *file, int line)
+#endif
 {
     gc_heap_t* heap = (gc_heap_t*) vheap;
     hmu_t *hmu = NULL;
@@ -364,19 +365,19 @@ gc_object_t _gc_alloc_vo_i_heap(void *vheap,
         /* integer overflow */
         return NULL;
 
-    gct_vm_mutex_lock(&heap->lock);
+    os_mutex_lock(&heap->lock);
 
     hmu = alloc_hmu_ex(heap, tot_size);
     if (!hmu)
-        goto FINISH;
+        goto finish;
 
     g_total_malloc += tot_size;
 
     hmu_set_ut(hmu, HMU_VO);
     hmu_unfree_vo(hmu);
 
-#if defined(GC_VERIFY)
-    hmu_init_prefix_and_suffix(hmu, tot_size, file_name, line_number);
+#if BH_ENABLE_GC_VERIFY != 0
+    hmu_init_prefix_and_suffix(hmu, tot_size, file, line);
 #endif
 
     ret = hmu_to_obj(hmu);
@@ -385,17 +386,22 @@ gc_object_t _gc_alloc_vo_i_heap(void *vheap,
         memset((uint8*)ret + size, 0, tot_size - tot_size_unaligned);
 
 #if BH_ENABLE_MEMORY_PROFILING != 0
-    os_printf("HEAP.ALLOC: heap: %p, size: %u", heap, size);
+    os_printf("HEAP.ALLOC: heap: %p, size: %u\n", heap, size);
 #endif
 
-FINISH:
-    gct_vm_mutex_unlock(&heap->lock);
-
+finish:
+    os_mutex_unlock(&heap->lock);
     return ret;
 }
 
-gc_object_t _gc_realloc_vo_i_heap(void *vheap, void *ptr,
-                                  gc_size_t size ALLOC_EXTRA_PARAMETERS)
+#if BH_ENABLE_GC_VERIFY == 0
+gc_object_t
+gc_realloc_vo(void *vheap, void *ptr, gc_size_t size)
+#else
+gc_object_t
+gc_realloc_vo_internal(void *vheap, void *ptr, gc_size_t size,
+                       const char *file, int line)
+#endif
 {
     gc_heap_t* heap = (gc_heap_t*) vheap;
     hmu_t *hmu = NULL, *hmu_old = NULL;
@@ -419,29 +425,29 @@ gc_object_t _gc_realloc_vo_i_heap(void *vheap, void *ptr,
             return obj_old;
     }
 
-    gct_vm_mutex_lock(&heap->lock);
+    os_mutex_lock(&heap->lock);
 
     hmu = alloc_hmu_ex(heap, tot_size);
     if (!hmu)
-        goto FINISH;
+        goto finish;
 
     g_total_malloc += tot_size;
 
     hmu_set_ut(hmu, HMU_VO);
     hmu_unfree_vo(hmu);
 
-#if defined(GC_VERIFY)
-    hmu_init_prefix_and_suffix(hmu, tot_size, file_name, line_number);
+#if BH_ENABLE_GC_VERIFY != 0
+    hmu_init_prefix_and_suffix(hmu, tot_size, file, line);
 #endif
 
     ret = hmu_to_obj(hmu);
 
 #if BH_ENABLE_MEMORY_PROFILING != 0
-    os_printf("HEAP.ALLOC: heap: %p, size: %u", heap, size);
+    os_printf("HEAP.ALLOC: heap: %p, size: %u\n", heap, size);
 #endif
 
-FINISH:
-    gct_vm_mutex_unlock(&heap->lock);
+finish:
+    os_mutex_unlock(&heap->lock);
 
     if (ret) {
         obj_size = tot_size - HMU_SIZE - OBJ_PREFIX_SIZE - OBJ_SUFFIX_SIZE;
@@ -450,18 +456,19 @@ gc_object_t _gc_realloc_vo_i_heap(void *vheap, void *ptr,
             obj_size_old = tot_size_old - HMU_SIZE
                            - OBJ_PREFIX_SIZE - OBJ_SUFFIX_SIZE;
             bh_memcpy_s(ret, obj_size, obj_old, obj_size_old);
-            gc_free_h(vheap, obj_old);
+            gc_free_vo(vheap, obj_old);
         }
     }
 
     return ret;
 }
 
-/* Do some checking to see if given pointer is a possible valid heap*/
-
-/* Return GC_TRUE if all checking passed*/
-/* Return GC_FALSE otherwise*/
-int gci_is_heap_valid(gc_heap_t *heap)
+/**
+ * Do some checking to see if given pointer is a possible valid heap
+ * @return GC_TRUE if all checking passed, GC_FALSE otherwise
+ */
+int
+gci_is_heap_valid(gc_heap_t *heap)
 {
     if (!heap)
         return GC_FALSE;
@@ -471,7 +478,14 @@ int gci_is_heap_valid(gc_heap_t *heap)
     return GC_TRUE;
 }
 
-int gc_free_i_heap(void *vheap, gc_object_t obj ALLOC_EXTRA_PARAMETERS)
+#if BH_ENABLE_GC_VERIFY == 0
+int
+gc_free_vo(void *vheap, gc_object_t obj)
+#else
+int
+gc_free_vo_internal(void *vheap, gc_object_t obj,
+                    const char *file, int line)
+#endif
 {
     gc_heap_t* heap = (gc_heap_t*) vheap;
     hmu_t *hmu = NULL;
@@ -487,11 +501,11 @@ int gc_free_i_heap(void *vheap, gc_object_t obj ALLOC_EXTRA_PARAMETERS)
 
     hmu = obj_to_hmu(obj);
 
-    gct_vm_mutex_lock(&heap->lock);
+    os_mutex_lock(&heap->lock);
 
-    if ((gc_uint8 *) hmu >= heap->base_addr
-            && (gc_uint8 *) hmu < heap->base_addr + heap->current_size) {
-#ifdef GC_VERIFY
+    if ((gc_uint8 *)hmu >= heap->base_addr
+        && (gc_uint8 *)hmu < heap->base_addr + heap->current_size) {
+#if BH_ENABLE_GC_VERIFY != 0
         hmu_verify(hmu);
 #endif
         ut = hmu_get_ut(hmu);
@@ -506,11 +520,9 @@ int gc_free_i_heap(void *vheap, gc_object_t obj ALLOC_EXTRA_PARAMETERS)
 
             g_total_free += size;
 
-#if GC_STAT_DATA != 0
             heap->total_free_size += size;
-#endif
 #if BH_ENABLE_MEMORY_PROFILING != 0
-            os_printf("HEAP.FREE, heap: %p, size: %u\n",heap, size);
+            os_printf("HEAP.FREE, heap: %p, size: %u\n", heap, size);
 #endif
 
             if (!hmu_get_pinuse(hmu)) {
@@ -546,54 +558,51 @@ int gc_free_i_heap(void *vheap, gc_object_t obj ALLOC_EXTRA_PARAMETERS)
         goto out;
     }
 
-    out:
-    gct_vm_mutex_unlock(&heap->lock);
+out:
+    os_mutex_unlock(&heap->lock);
     return ret;
 }
 
-void gc_dump_heap_stats(gc_heap_t *heap)
+void
+gc_dump_heap_stats(gc_heap_t *heap)
 {
     os_printf("heap: %p, heap start: %p\n", heap, heap->base_addr);
-    os_printf(
-            "total malloc: totalfree: %u, current: %u, highmark: %u, gc cnt: %u\n",
-            heap->total_free_size, heap->current_size, heap->highmark_size,
-            heap->total_gc_count);
+    os_printf("total free: %u, current: %u, highmark: %u\n",
+              heap->total_free_size, heap->current_size, heap->highmark_size);
     os_printf("g_total_malloc=%lu, g_total_free=%lu, occupied=%lu\n",
-            g_total_malloc, g_total_free, g_total_malloc - g_total_free);
+              g_total_malloc, g_total_free, g_total_malloc - g_total_free);
 }
 
-#ifdef GC_TEST
-
-void gci_dump(char* buf, gc_heap_t *heap)
+void
+gci_dump(gc_heap_t *heap)
 {
     hmu_t *cur = NULL, *end = NULL;
     hmu_type_t ut;
     gc_size_t size;
-    int i = 0;
-    int p;
-    char inuse;
-    int mark;
+    int i = 0, p, mark;
+    char inuse = 'U';
 
     cur = (hmu_t*)heap->base_addr;
     end = (hmu_t*)((char*)heap->base_addr + heap->current_size);
 
-    while(cur < end)
-    {
+    while(cur < end) {
         ut = hmu_get_ut(cur);
         size = hmu_get_size(cur);
         p = hmu_get_pinuse(cur);
         mark = hmu_is_jo_marked (cur);
 
-        if(ut == HMU_VO)
-        inuse = 'V';
-        else if(ut == HMU_JO)
-        inuse = hmu_is_jo_marked(cur) ? 'J' : 'j';
-        else if(ut == HMU_FC)
-        inuse = 'F';
+        if (ut == HMU_VO)
+            inuse = 'V';
+        else if (ut == HMU_JO)
+            inuse = hmu_is_jo_marked(cur) ? 'J' : 'j';
+        else if (ut == HMU_FC)
+            inuse = 'F';
 
         bh_assert(size > 0);
 
-        buf += sprintf(buf, "#%d %08x %x %x %d %c %d\n", i, (char*) cur - (char*) heap->base_addr, ut, p, mark, inuse, hmu_obj_size(size));
+        os_printf("#%d %08x %x %x %d %c %d\n",
+                  i, (int32)((char*) cur - (char*) heap->base_addr),
+                  ut, p, mark, inuse, (int32)hmu_obj_size(size));
 
         cur = (hmu_t*)((char *)cur + size);
         i++;
@@ -602,4 +611,3 @@ void gci_dump(char* buf, gc_heap_t *heap)
     bh_assert(cur == end);
 }
 
-#endif
diff --git a/core/shared/mem-alloc/ems/ems_gc.h b/core/shared/mem-alloc/ems/ems_gc.h
index 77de51c881..636d3b5e5a 100644
--- a/core/shared/mem-alloc/ems/ems_gc.h
+++ b/core/shared/mem-alloc/ems/ems_gc.h
@@ -21,43 +21,8 @@
 extern "C" {
 #endif
 
-/*Pre-compile configuration can be done here or on Makefiles*/
-/*#define GC_EMBEDDED or GC_STANDALONE*/
-/*#define GC_DEBUG*/
-/*#define GC_TEST // TEST mode is a sub-mode of STANDALONE*/
-/* #define GC_ALLOC_TRACE */
-/* #define GC_STAT */
-#ifndef GC_STAT_DATA
-#define GC_STAT_DATA 1
-#endif
-
 #define GC_HEAD_PADDING 4
 
-/* Standalone GC is used for testing.*/
-#ifndef GC_EMBEDDED
-#    ifndef GC_STANDALONE
-#        define GC_STANDALONE
-#    endif
-#endif
-
-#if defined(GC_EMBEDDED) && defined(GC_STANDALONE)
-#    error "Can not define GC_EMBEDDED and GC_STANDALONE at the same time"
-#endif
-
-#if BH_DEBUG != 0
-/*instrument mode ignore GC_DEBUG feature, for instrument testing gc_alloc_vo_i_heap only has func_name parameter*/
-#if !defined INSTRUMENT_TEST_ENABLED && !defined GC_DEBUG
-#        define GC_DEBUG
-#endif
-#endif
-
-#if defined(GC_EMBEDDED) && defined(GC_TEST)
-#    error "Can not defined GC_EMBEDDED and GC_TEST at the same time"
-#endif
-
-typedef void *gc_handle_t;
-typedef void *gc_object_t;
-
 #define NULL_REF ((gc_object_t)NULL)
 
 #define GC_SUCCESS (0)
@@ -68,72 +33,23 @@ typedef void *gc_object_t;
 
 #define GC_MAX_HEAP_SIZE (256 * BH_KB)
 
-typedef int64 gc_int64;
-
-typedef unsigned int gc_uint32;
-typedef signed int gc_int32;
-typedef unsigned short gc_uint16;
-typedef signed short gc_int16;
-typedef unsigned char gc_uint8;
-typedef signed char gc_int8;
-typedef gc_uint32 gc_size_t;
-
-typedef enum {
-    MMT_SHARED = 0,
-    MMT_INSTANCE = 1,
-    MMT_APPMANAGER = MMT_SHARED,
-    MMT_VERIFIER = MMT_SHARED,
-    MMT_JHI = MMT_SHARED,
-    MMT_LOADER = MMT_SHARED,
-    MMT_APPLET = MMT_INSTANCE,
-    MMT_INTERPRETER = MMT_INSTANCE
-} gc_mm_t;
-
-#ifdef GC_STAT
-#define GC_HEAP_STAT_SIZE (128 / 4)
-
-typedef struct {
-    int usage;
-    int usage_block;
-    int vo_usage;
-    int jo_usage;
-    int free;
-    int free_block;
-    int vo_free;
-    int jo_free;
-    int usage_sizes[GC_HEAP_STAT_SIZE];
-    int free_sizes[GC_HEAP_STAT_SIZE];
-}gc_stat_t;
-
-extern void gc_heap_stat(void* heap, gc_stat_t* gc_stat);
-extern void __gc_print_stat(void *heap, int verbose);
-
-#define gc_print_stat __gc_print_stat
-
-#else
-
-#define gc_print_stat(heap, verbose)
-
-#endif
-
-#if GC_STAT_DATA != 0
+typedef void * gc_handle_t;
+typedef void * gc_object_t;
+typedef int64  gc_int64;
+typedef uint32 gc_uint32;
+typedef int32  gc_int32;
+typedef uint16 gc_uint16;
+typedef int16  gc_int16;
+typedef uint8  gc_uint8;
+typedef int8   gc_int8;
+typedef uint32 gc_size_t;
 
 typedef enum {
     GC_STAT_TOTAL = 0,
     GC_STAT_FREE,
     GC_STAT_HIGHMARK,
-    GC_STAT_COUNT,
-    GC_STAT_TIME,
-    GC_STAT_MAX_1,
-    GC_STAT_MAX_2,
-    GC_STAT_MAX_3,
-    GC_STAT_MAX
 } GC_STAT_INDEX;
 
-#endif
-
-/*////////////// Exported APIs*/
-
 /**
  * GC initialization from a buffer
  *
@@ -142,7 +58,8 @@ typedef enum {
  *
  * @return gc handle if success, NULL otherwise
  */
-extern gc_handle_t gc_init_with_pool(char *buf, gc_size_t buf_size);
+gc_handle_t
+gc_init_with_pool(char *buf, gc_size_t buf_size);
 
 /**
  * Destroy heap which is initilized from a buffer
@@ -152,9 +69,8 @@ extern gc_handle_t gc_init_with_pool(char *buf, gc_size_t buf_size);
  * @return GC_SUCCESS if success
  *         GC_ERROR for bad parameters or failed system resource freeing.
  */
-extern int gc_destroy_with_pool(gc_handle_t handle);
-
-#if GC_STAT_DATA != 0
+int
+gc_destroy_with_pool(gc_handle_t handle);
 
 /**
  * Get Heap Stats
@@ -163,166 +79,44 @@ extern int gc_destroy_with_pool(gc_handle_t handle);
  * @param size [in] the size of stats
  * @param mmt [in] type of heap, MMT_SHARED or MMT_INSTANCE
  */
-extern void* gc_heap_stats(void *heap, uint32* stats, int size, gc_mm_t mmt);
+void *
+gc_heap_stats(void *heap, uint32* stats, int size);
 
-/**
- * Set GC threshold factor
- *
- * @param heap [in] the heap to set
- * @param factor [in] the threshold size is free_size * factor / 1000
- *
- * @return GC_SUCCESS if success.
- */
-extern int gc_set_threshold_factor(void *heap, unsigned int factor);
+#if BH_ENABLE_GC_VERIFY == 0
 
-#endif
+gc_object_t
+gc_alloc_vo(void *heap, gc_size_t size);
 
-/*////// Allocate heap object*/
+gc_object_t
+gc_realloc_vo(void *heap, void *ptr, gc_size_t size);
 
-/* There are two versions of allocate functions. The functions with _i suffix should be only used*/
-/*  internally. Functions without _i suffix are just wrappers with the corresponded functions with*/
-/*  _i suffix. Allocation operation code position are record under DEBUG model for debugging.*/
-#ifdef GC_DEBUG
-#    define ALLOC_EXTRA_PARAMETERS ,const char*file_name,int line_number
-#    define ALLOC_EXTRA_ARGUMENTS , __FILE__, __LINE__
-#    define ALLOC_PASSDOWN_EXTRA_ARGUMENTS , file_name, line_number
-#    define gc_alloc_vo_h(heap, size) gc_alloc_vo_i_heap(heap, size, __FILE__, __LINE__)
-#    define gc_realloc_vo_h(heap, ptr, size) gc_realloc_vo_i_heap(heap, ptr, size, __FILE__, __LINE__)
-#    define gc_free_h(heap, obj) gc_free_i_heap(heap, obj, __FILE__, __LINE__)
-#else
-#    define ALLOC_EXTRA_PARAMETERS
-#    define ALLOC_EXTRA_ARGUMENTS
-#    define ALLOC_PASSDOWN_EXTRA_ARGUMENTS
-#    define gc_alloc_vo_h                    gc_alloc_vo_i_heap
-#    define gc_realloc_vo_h                  gc_realloc_vo_i_heap
-#    define gc_free_h                        gc_free_i_heap
-#endif
+int
+gc_free_vo(void *heap, gc_object_t obj);
 
-/**
- * Invoke a GC
- *
- * @param heap
- *
- * @return GC_SUCCESS if success
- */
-extern int gci_gc_heap(void *heap);
+#else /* else of BH_ENABLE_GC_VERIFY */
 
-/**
- * Allocate VM Object in specific heap.
- *
- * @param heap heap to allocate.
- * @param size bytes to allocate.
- *
- * @return pointer to VM object allocated
- *         NULL if failed.
- */
-extern gc_object_t _gc_alloc_vo_i_heap(void *heap,
-                                       gc_size_t size ALLOC_EXTRA_PARAMETERS);
-extern gc_object_t _gc_realloc_vo_i_heap(void *heap, void *ptr,
-                                         gc_size_t size ALLOC_EXTRA_PARAMETERS);
-extern gc_object_t _gc_alloc_jo_i_heap(void *heap,
-                                       gc_size_t size ALLOC_EXTRA_PARAMETERS);
-#ifdef INSTRUMENT_TEST_ENABLED
-extern gc_object_t gc_alloc_vo_i_heap_instr(void *heap, gc_size_t size, const char* func_name );
-extern gc_object_t gc_realloc_vo_i_heap_instr(void *heap, void *ptr, gc_size_t size,
-                                              const char* func_name );
-extern gc_object_t gc_alloc_jo_i_heap_instr(void *heap, gc_size_t size, const char* func_name);
-#    define gc_alloc_vo_i_heap(heap, size) gc_alloc_vo_i_heap_instr(heap, size, __FUNCTION__)
-#    define gc_realloc_vo_i_heap(heap, ptr, size) gc_realloc_vo_i_heap_instr(heap, ptr, size, __FUNCTION__)
-#    define gc_alloc_jo_i_heap(heap, size) gc_alloc_jo_i_heap_instr(heap, size, __FUNCTION__)
-#else
-#    define gc_alloc_vo_i_heap _gc_alloc_vo_i_heap
-#    define gc_realloc_vo_i_heap _gc_realloc_vo_i_heap
-#    define gc_alloc_jo_i_heap _gc_alloc_jo_i_heap
-#endif
+gc_object_t
+gc_alloc_vo_internal(void *heap, gc_size_t size,
+                     const char *file, int line);
 
-/**
- * Allocate Java object in specific heap.
- *
- * @param heap heap to allocate.
- * @param size bytes to allocate.
- *
- * @return pointer to Java object allocated
- *         NULL if failed.
- */
-extern gc_object_t _gc_alloc_jo_i_heap(void *heap,
-        gc_size_t size ALLOC_EXTRA_PARAMETERS);
+gc_object_t
+gc_realloc_vo_internal(void *heap, void *ptr, gc_size_t size,
+                       const char *file, int line);
 
-/**
- * Free VM object
- *
- * @param heap heap to free.
- * @param obj pointer to object need free.
- *
- * @return GC_SUCCESS if success
- */
-extern int gc_free_i_heap(void *heap, gc_object_t obj ALLOC_EXTRA_PARAMETERS);
+int
+gc_free_vo_internal(void *heap, gc_object_t obj,
+                    const char *file, int line);
 
-/**
- * Add ref to rootset of gc for current instance.
- *
- * @param obj pointer to real load of a valid Java object managed by gc for current instance.
- *
- * @return GC_SUCCESS if success.
- *         GC_ERROR for invalid parameters.
- */
-extern int gc_add_root(void* heap, gc_object_t obj);
+#define gc_alloc_vo(heap, size) \
+    gc_alloc_vo_internal(heap, size, __FILE__, __LINE__)
 
-/*////////////// Imported APIs which should be implemented in other components*/
+#define gc_realloc_vo(heap, ptr, size) \
+    gc_realloc_vo_internal(heap, ptr, size, __FILE__, __LINE__)
 
-/*////// Java object layout related APIs*/
+#define gc_free_vo(heap, obj) \
+    gc_free_vo_internal(heap, obj, __FILE__, __LINE__)
 
-/**
- * Get Java object size from corresponding VM module
- *
- * @param obj pointer to the real load of a Java object.
- *
- * @return size of java object.
- */
-extern gc_size_t vm_get_java_object_size(gc_object_t obj);
-
-/**
- * Get reference list of this object
- *
- * @param obj [in] pointer to java object.
- * @param is_compact_mode [in] indicate the java object mode. GC_TRUE or GC_FALSE.
- * @param ref_num [out] the size of ref_list.
- * @param ref_list [out] if is_compact_mode is GC_FALSE, this parameter will be set to a list of offset.
- * @param ref_start_offset [out] If is_compact_mode is GC_TRUE, this parameter will be set to the start offset of the references in this object.
- *
- * @return GC_SUCCESS if success.
- *         GC_ERROR when error occurs.
- */
-extern int vm_get_java_object_ref_list(gc_object_t obj, int *is_compact_mode,
-        gc_size_t *ref_num, gc_uint16 **ref_list, gc_uint32 *ref_start_offset);
-
-/**
- * Get gc handle for current instance
- *
- *
- * @return instance heap handle.
- */
-extern gc_handle_t app_manager_get_cur_applet_heap(void);
-
-/**
- * Begin current instance heap rootset enumeration
- *
- *
- * @return GC_SUCCESS if success.
- *         GC_ERROR when error occurs.
- */
-extern int vm_begin_rootset_enumeration(void *heap);
-
-#ifdef _INSTRUMENT_TEST_ENABLED
-extern int vm_begin_rootset_enumeration_instr(void *heap, const char*func_name);
-#define vm_begin_rootset_enumeration(heap) vm_begin_rootset_enumeration_instr(heap, __FUNCTION__)
-#else
-#define vm_begin_rootset_enumeration _vm_begin_rootset_enumeration
-#endif    /* INSTUMENT_TEST_ENABLED*/
-
-#ifndef offsetof
-#define offsetof(Type, field) ((size_t)(&((Type *)0)->field))
-#endif
+#endif /* end of BH_ENABLE_GC_VERIFY */
 
 #ifdef __cplusplus
 }
diff --git a/core/shared/mem-alloc/ems/ems_gc_internal.h b/core/shared/mem-alloc/ems/ems_gc_internal.h
index 24dafeff5c..717149b9f9 100644
--- a/core/shared/mem-alloc/ems/ems_gc_internal.h
+++ b/core/shared/mem-alloc/ems/ems_gc_internal.h
@@ -13,54 +13,53 @@ extern "C" {
 #include "bh_platform.h"
 #include "ems_gc.h"
 
-/* basic block managed by EMS gc is the so-called HMU (heap memory unit)*/
-typedef enum _hmu_type_enum
-{
+/* HMU (heap memory unit) basic block type */
+typedef enum hmu_type_enum {
     HMU_TYPE_MIN = 0,
     HMU_TYPE_MAX = 3,
     HMU_JO = 3,
     HMU_VO = 2,
     HMU_FC = 1,
     HMU_FM = 0
-}hmu_type_t;
+} hmu_type_t;
 
-typedef struct _hmu_struct
-{
+typedef struct hmu_struct {
     gc_uint32 header;
-}hmu_t;
+} hmu_t;
 
-#if defined(GC_VERIFY)
+#if BH_ENABLE_GC_VERIFY != 0
 
 #define GC_OBJECT_PREFIX_PADDING_CNT 3
 #define GC_OBJECT_SUFFIX_PADDING_CNT 4
 #define GC_OBJECT_PADDING_VALUE (0x12345678)
 
-typedef struct _gc_object_prefix
-{
+typedef struct gc_object_prefix {
     const char *file_name;
     gc_int32 line_no;
     gc_int32 size;
     gc_uint32 padding[GC_OBJECT_PREFIX_PADDING_CNT];
-}gc_object_prefix_t;
-
-#define OBJ_PREFIX_SIZE (sizeof(gc_object_prefix_t))
+} gc_object_prefix_t;
 
-typedef struct _gc_object_suffix
-{
+typedef struct gc_object_suffix {
     gc_uint32 padding[GC_OBJECT_SUFFIX_PADDING_CNT];
-}gc_object_suffix_t;
+} gc_object_suffix_t;
 
+#define OBJ_PREFIX_SIZE (sizeof(gc_object_prefix_t))
 #define OBJ_SUFFIX_SIZE (sizeof(gc_object_suffix_t))
 
-extern void hmu_init_prefix_and_suffix(hmu_t *hmu, gc_size_t tot_size, const char *file_name, int line_no);
-extern void hmu_verify(hmu_t *hmu);
+void
+hmu_init_prefix_and_suffix(hmu_t *hmu, gc_size_t tot_size,
+                           const char *file_name, int line_no);
+
+void
+hmu_verify(hmu_t *hmu);
 
 #define SKIP_OBJ_PREFIX(p) ((void*)((gc_uint8*)(p) + OBJ_PREFIX_SIZE))
 #define SKIP_OBJ_SUFFIX(p) ((void*)((gc_uint8*)(p) + OBJ_SUFFIX_SIZE))
 
 #define OBJ_EXTRA_SIZE (HMU_SIZE + OBJ_PREFIX_SIZE + OBJ_SUFFIX_SIZE)
 
-#else
+#else /* else of BH_ENABLE_GC_VERIFY */
 
 #define OBJ_PREFIX_SIZE 0
 #define OBJ_SUFFIX_SIZE 0
@@ -70,7 +69,7 @@ extern void hmu_verify(hmu_t *hmu);
 
 #define OBJ_EXTRA_SIZE (HMU_SIZE + OBJ_PREFIX_SIZE + OBJ_SUFFIX_SIZE)
 
-#endif /* GC_DEBUG*/
+#endif /* end of BH_ENABLE_GC_VERIFY */
 
 #define hmu_obj_size(s) ((s)-OBJ_EXTRA_SIZE)
 
@@ -79,7 +78,9 @@ extern void hmu_verify(hmu_t *hmu);
 #define GC_SMALLEST_SIZE GC_ALIGN_8(HMU_SIZE + OBJ_PREFIX_SIZE + OBJ_SUFFIX_SIZE + 8)
 #define GC_GET_REAL_SIZE(x) GC_ALIGN_8(HMU_SIZE + OBJ_PREFIX_SIZE + OBJ_SUFFIX_SIZE + (((x) > 8) ? (x): 8))
 
-/*////// functions for bit operation*/
+/**
+ * hmu bit operation
+ */
 
 #define SETBIT(v, offset) (v) |= (1 << (offset))
 #define GETBIT(v, offset) ((v) & (1 << (offset)) ? 1 : 0)
@@ -92,7 +93,9 @@ extern void hmu_verify(hmu_t *hmu);
 #define CLRBITS(v, offset, size) (v) &= ~(((1 << size) - 1) << offset)
 #define GETBITS(v, offset, size) (((v) & ((uint32)(((1 << size) - 1) << offset))) >> offset)
 
-/*////// gc object layout definition*/
+/**
+ * gc object layout definition
+ */
 
 #define HMU_SIZE (sizeof(hmu_t))
 
@@ -121,6 +124,12 @@ extern void hmu_verify(hmu_t *hmu);
 #define hmu_unmark_jo(hmu) CLRBIT ((hmu)->header, HMU_JO_MB_OFFSET)
 #define hmu_is_jo_marked(hmu) GETBIT ((hmu)->header, HMU_JO_MB_OFFSET)
 
+/**
+ * The hmu size is divisible by 8, its lowest 3 bits are 0, so we only
+ * store its higher bits of bit [29..3], and bit [2..0] are not stored.
+ * After that, the maximal heap size can be enlarged from (1<<27) = 128MB
+ * to (1<<27) * 8 = 1GB.
+ */
 #define HMU_SIZE_SIZE 27
 #define HMU_SIZE_OFFSET 0
 
@@ -129,10 +138,12 @@ extern void hmu_verify(hmu_t *hmu);
 #define hmu_is_vo_freed(hmu) GETBIT ((hmu)->header, HMU_VO_FB_OFFSET)
 #define hmu_unfree_vo(hmu) CLRBIT ((hmu)->header, HMU_VO_FB_OFFSET)
 
-#define hmu_get_size(hmu) GETBITS ((hmu)->header, HMU_SIZE_OFFSET, HMU_SIZE_SIZE)
-#define hmu_set_size(hmu, size) SETBITS ((hmu)->header, HMU_SIZE_OFFSET, HMU_SIZE_SIZE, size)
+#define hmu_get_size(hmu) (GETBITS ((hmu)->header, HMU_SIZE_OFFSET, HMU_SIZE_SIZE) << 3)
+#define hmu_set_size(hmu, size) SETBITS ((hmu)->header, HMU_SIZE_OFFSET, HMU_SIZE_SIZE, ((size) >> 3))
 
-/*////// HMU free chunk management*/
+/**
+ * HMU free chunk management
+ */
 
 #define HMU_NORMAL_NODE_CNT 32
 #define HMU_FC_NORMAL_MAX_SIZE ((HMU_NORMAL_NODE_CNT - 1) << 3)
@@ -141,51 +152,43 @@ extern void hmu_verify(hmu_t *hmu);
 #error "Too small GC_MAX_HEAP_SIZE"
 #endif
 
-typedef struct _hmu_normal_node
-{
+typedef struct hmu_normal_node {
     hmu_t hmu_header;
-#if defined(BUILD_TARGET_X86_64) || defined(BUILD_TARGET_AMD_64)
-    struct {
-        uint32 parts[2];
-    } next;
-#else
-    struct _hmu_normal_node *next;
-#endif
+    gc_int32 next_offset;
 } hmu_normal_node_t;
 
-#if defined(BUILD_TARGET_X86_64) || defined(BUILD_TARGET_AMD_64)
 static inline hmu_normal_node_t *
 get_hmu_normal_node_next(hmu_normal_node_t *node)
 {
-    hmu_normal_node_t *next;
-    bh_memcpy_s(&next, (uint32)sizeof(hmu_normal_node_t *),
-                &node->next.parts, (uint32)sizeof(uint32) * 2);
-    return next;
+    return node->next_offset
+           ? (hmu_normal_node_t *)((uint8*)node + node->next_offset)
+           : NULL;
 }
 
 static inline void
 set_hmu_normal_node_next(hmu_normal_node_t *node, hmu_normal_node_t *next)
 {
-    bh_memcpy_s(&node->next.parts, (uint32)sizeof(uint32) * 2,
-                &next, (uint32)sizeof(hmu_normal_node_t *));
+    if (next) {
+        bh_assert((uint8*)next - (uint8*)node < INT32_MAX);
+        node->next_offset = (gc_int32)(intptr_t)
+                            ((uint8*)next - (uint8*)node);
+    }
+    else {
+        node->next_offset = 0;
+    }
 }
-#else
-#define get_hmu_normal_node_next(node) (node)->next
-#define set_hmu_normal_node_next(node, _next) (node)->next = _next
-#endif
 
-typedef struct _hmu_tree_node
-{
+typedef struct hmu_tree_node {
     hmu_t hmu_header;
     gc_size_t size;
-    struct _hmu_tree_node *left;
-    struct _hmu_tree_node *right;
-    struct _hmu_tree_node *parent;
+    struct hmu_tree_node *left;
+    struct hmu_tree_node *right;
+    struct hmu_tree_node *parent;
 } hmu_tree_node_t;
 
-typedef struct _gc_heap_struct
-{
-    gc_handle_t heap_id; /* for double checking*/
+typedef struct gc_heap_struct {
+    /* for double checking*/
+    gc_handle_t heap_id;
 
     gc_uint8 *base_addr;
     gc_size_t current_size;
@@ -198,95 +201,32 @@ typedef struct _gc_heap_struct
     /* order in kfc_tree is: size[left] <= size[cur] < size[right]*/
     hmu_tree_node_t kfc_tree_root;
 
-    /* for rootset enumeration of private heap*/
-    void *root_set;
-
-    /* whether the fast mode of marking process that requires
-     additional memory fails.  When the fast mode fails, the
-     marking process can still be done in the slow mode, which
-     doesn't need additional memory (by walking through all
-     blocks and marking sucessors of marked nodes until no new
-     node is marked).  TODO: slow mode is not implemented.  */
-    unsigned is_fast_marking_failed : 1;
-
-#if GC_STAT_DATA != 0
-    gc_size_t highmark_size;
     gc_size_t init_size;
-    gc_size_t total_gc_count;
+    gc_size_t highmark_size;
     gc_size_t total_free_size;
-    gc_size_t gc_threshold;
-    gc_size_t gc_threshold_factor;
-    gc_int64 total_gc_time;
-#endif
 } gc_heap_t;
 
-/*////// MISC internal used APIs*/
-
-extern void gci_add_fc(gc_heap_t *heap, hmu_t *hmu, gc_size_t size);
-extern int gci_is_heap_valid(gc_heap_t *heap);
-
-#ifdef GC_DEBUG
-extern void gci_verify_heap(gc_heap_t *heap);
-extern void gci_dump(char* buf, gc_heap_t *heap);
-#endif
-
-#if GC_STAT_DATA != 0
-
-/* the default GC threshold size is free_size * GC_DEFAULT_THRESHOLD_FACTOR / 1000 */
-#define GC_DEFAULT_THRESHOLD_FACTOR 400
+/**
+ * MISC internal used APIs
+ */
 
-static inline void gc_update_threshold(gc_heap_t *heap)
-{
-    heap->gc_threshold = heap->total_free_size * heap->gc_threshold_factor / 1000;
-}
-#endif
+void
+gci_add_fc(gc_heap_t *heap, hmu_t *hmu, gc_size_t size);
 
-/*////// MISC data structures*/
+int
+gci_is_heap_valid(gc_heap_t *heap);
 
-#define MARK_NODE_OBJ_CNT 256
+/**
+ * Verify heap integrity
+ */
+void
+gci_verify_heap(gc_heap_t *heap);
 
-/* mark node is used for gc marker*/
-typedef struct _mark_node_struct
-{
-    /* number of to-expand objects can be saved in this node*/
-    gc_size_t cnt;
-
-    /* the first unused index*/
-    int idx;
-
-    /* next node on the node list*/
-    struct _mark_node_struct *next;
-
-    /* the actual to-expand objects list*/
-    gc_object_t set[MARK_NODE_OBJ_CNT];
-}mark_node_t;
-
-/*////// Imported APIs wrappers under TEST mode*/
-
-#ifdef GC_TEST
-extern int (*gct_vm_get_java_object_ref_list)(
-        gc_object_t obj,
-        int *is_compact_mode, /* can be set to GC_TRUE, or GC_FALSE */
-        gc_size_t *ref_num,
-        gc_uint16 **ref_list,
-        gc_uint32 *ref_start_offset);
-extern int (*gct_vm_mutex_init)(korp_mutex *mutex);
-extern int (*gct_vm_mutex_destroy)(korp_mutex *mutex);
-extern int (*gct_vm_mutex_lock)(korp_mutex *mutex);
-extern int (*gct_vm_mutex_unlock)(korp_mutex *mutex);
-extern gc_handle_t (*gct_vm_get_gc_handle_for_current_instance)(void);
-extern int (*gct_vm_begin_rootset_enumeration)(void* heap);
-extern int (*gct_vm_gc_finished)(void);
-#else
-#define gct_vm_get_java_object_ref_list             bh_get_java_object_ref_list
-#define gct_vm_mutex_init                           os_mutex_init
-#define gct_vm_mutex_destroy                        os_mutex_destroy
-#define gct_vm_mutex_lock                           os_mutex_lock
-#define gct_vm_mutex_unlock                         os_mutex_unlock
-#define gct_vm_get_gc_handle_for_current_instance   app_manager_get_cur_applet_heap
-#define gct_vm_begin_rootset_enumeration            vm_begin_rootset_enumeration
-#define gct_vm_gc_finished                          jeff_runtime_gc_finished
-#endif
+/**
+ * Dump heap nodes
+ */
+void
+gci_dump(gc_heap_t *heap);
 
 #ifdef __cplusplus
 }
diff --git a/core/shared/mem-alloc/ems/ems_hmu.c b/core/shared/mem-alloc/ems/ems_hmu.c
index 0a6d1abc31..555989b5b3 100644
--- a/core/shared/mem-alloc/ems/ems_hmu.c
+++ b/core/shared/mem-alloc/ems/ems_hmu.c
@@ -5,13 +5,19 @@
 
 #include "ems_gc_internal.h"
 
-#if defined(GC_VERIFY)
-/* Set default value to prefix and suffix*/
+#if BH_ENABLE_GC_VERIFY != 0
 
-/* @hmu should not be NULL and it should have been correctly initilized (except for prefix and suffix part)*/
-/* @tot_size is offered here because hmu_get_size can not be used till now. @tot_size should not be smaller than OBJ_EXTRA_SIZE.*/
-/*  For VO, @tot_size should be equal to object total size.*/
-void hmu_init_prefix_and_suffix(hmu_t *hmu, gc_size_t tot_size, const char *file_name, int line_no)
+/**
+ * Set default value to prefix and suffix
+ * @param hmu should not be NULL and should have been correctly initilized
+ *        (except prefix and suffix part)
+ * @param tot_size is offered here because hmu_get_size can not be used till now.
+ *        tot_size should not be smaller than OBJ_EXTRA_SIZE.
+ *        For VO, tot_size should be equal to object total size.
+ */
+void
+hmu_init_prefix_and_suffix(hmu_t *hmu, gc_size_t tot_size,
+                           const char *file_name, int line_no)
 {
     gc_object_prefix_t *prefix = NULL;
     gc_object_suffix_t *suffix = NULL;
@@ -28,17 +34,18 @@ void hmu_init_prefix_and_suffix(hmu_t *hmu, gc_size_t tot_size, const char *file
     prefix->file_name = file_name;
     prefix->line_no = line_no;
     prefix->size = tot_size;
-    for(i = 0;i < GC_OBJECT_PREFIX_PADDING_CNT;i++)
-    {
+
+    for(i = 0;i < GC_OBJECT_PREFIX_PADDING_CNT;i++) {
         prefix->padding[i] = GC_OBJECT_PADDING_VALUE;
     }
-    for(i = 0;i < GC_OBJECT_SUFFIX_PADDING_CNT;i++)
-    {
+
+    for(i = 0;i < GC_OBJECT_SUFFIX_PADDING_CNT;i++) {
         suffix->padding[i] = GC_OBJECT_PADDING_VALUE;
     }
 }
 
-void hmu_verify(hmu_t *hmu)
+void
+hmu_verify(hmu_t *hmu)
 {
     gc_object_prefix_t *prefix = NULL;
     gc_object_suffix_t *suffix = NULL;
@@ -83,5 +90,6 @@ void hmu_verify(hmu_t *hmu)
         bh_assert(is_padding_ok);
     }
 }
-#endif
+
+#endif /* end of BH_ENABLE_GC_VERIFY */
 
diff --git a/core/shared/mem-alloc/ems/ems_kfc.c b/core/shared/mem-alloc/ems/ems_kfc.c
index ec4031fca4..d0ec2548a7 100644
--- a/core/shared/mem-alloc/ems/ems_kfc.c
+++ b/core/shared/mem-alloc/ems/ems_kfc.c
@@ -5,37 +5,8 @@
 
 #include "ems_gc_internal.h"
 
-
-#define HEAP_INC_FACTOR 1
-
-/* Check if current platform is compatible with current GC design*/
-
-/* Return GC_ERROR if not;*/
-/* Return GC_SUCCESS otherwise.*/
-int gci_check_platform()
-{
-#define CHECK(x, y)  do {                                       \
-  if((x) != (y)) {                                              \
-    os_printf("Platform checking failed on LINE %d at FILE %s.",\
-           __LINE__, __FILE__);                                 \
-    return GC_ERROR;                                            \
-  }                                                             \
-} while(0)
-
-    CHECK(8, sizeof(gc_int64));
-    CHECK(4, sizeof(gc_uint32));
-    CHECK(4, sizeof(gc_int32));
-    CHECK(2, sizeof(gc_uint16));
-    CHECK(2, sizeof(gc_int16));
-    CHECK(1, sizeof(gc_int8));
-    CHECK(1, sizeof(gc_uint8));
-    CHECK(4, sizeof(gc_size_t));
-    /*CHECK(4, sizeof(void *));*/
-
-    return GC_SUCCESS;
-}
-
-gc_handle_t gc_init_with_pool(char *buf, gc_size_t buf_size)
+gc_handle_t
+gc_init_with_pool(char *buf, gc_size_t buf_size)
 {
     char *buf_end = buf + buf_size;
     char *buf_aligned = (char*) (((uintptr_t) buf + 7) & (uintptr_t)~7);
@@ -46,14 +17,8 @@ gc_handle_t gc_init_with_pool(char *buf, gc_size_t buf_size)
     hmu_tree_node_t *root = NULL, *q = NULL;
     int i = 0, ret;
 
-    /* check system compatibility*/
-    if (gci_check_platform() == GC_ERROR) {
-        os_printf("Check platform compatibility failed");
-        return NULL;
-    }
-
     if (buf_size < 1024) {
-        os_printf("[GC_ERROR]heap_init_size(%d) < 1024", buf_size);
+        os_printf("[GC_ERROR]heap_init_size(%d) < 1024\n", buf_size);
         return NULL;
     }
 
@@ -63,30 +28,20 @@ gc_handle_t gc_init_with_pool(char *buf, gc_size_t buf_size)
     memset(heap, 0, sizeof *heap);
     memset(base_addr, 0, heap_max_size);
 
-    ret = gct_vm_mutex_init(&heap->lock);
+    ret = os_mutex_init(&heap->lock);
     if (ret != BHT_OK) {
-        os_printf("[GC_ERROR]failed to init lock ");
+        os_printf("[GC_ERROR]failed to init lock\n");
         return NULL;
     }
 
-#ifdef BH_FOOTPRINT
-    os_printf("\nINIT HEAP 0x%08x %d\n", base_addr, heap_max_size);
-#endif
-
     /* init all data structures*/
     heap->max_size = heap_max_size;
     heap->current_size = heap_max_size;
-    heap->base_addr = (gc_uint8*) base_addr;
-    heap->heap_id = (gc_handle_t) heap;
+    heap->base_addr = (gc_uint8*)base_addr;
+    heap->heap_id = (gc_handle_t)heap;
 
-#if GC_STAT_DATA != 0
     heap->total_free_size = heap->current_size;
     heap->highmark_size = 0;
-    heap->total_gc_count = 0;
-    heap->total_gc_time = 0;
-    heap->gc_threshold_factor = GC_DEFAULT_THRESHOLD_FACTOR;
-    gc_update_threshold(heap);
-#endif
 
     for (i = 0; i < HMU_NORMAL_NODE_CNT; i++) {
         /* make normal node look like a FC*/
@@ -112,30 +67,29 @@ gc_handle_t gc_init_with_pool(char *buf, gc_size_t buf_size)
     q->parent = root;
     q->size = heap->current_size;
 
-    bh_assert(
-            root->size <= HMU_FC_NORMAL_MAX_SIZE
-                    && HMU_FC_NORMAL_MAX_SIZE < q->size); /*@NOTIFY*/
+    bh_assert(root->size <= HMU_FC_NORMAL_MAX_SIZE
+              && HMU_FC_NORMAL_MAX_SIZE < q->size);
 
 #if BH_ENABLE_MEMORY_PROFILING != 0
-    os_printf("heap is successfully initialized with max_size=%u.",
+    os_printf("heap is successfully initialized with max_size=%u.\n",
               heap_max_size);
 #endif
     return heap;
 }
 
-int gc_destroy_with_pool(gc_handle_t handle)
+int
+gc_destroy_with_pool(gc_handle_t handle)
 {
     gc_heap_t *heap = (gc_heap_t *) handle;
-    gct_vm_mutex_destroy(&heap->lock);
+    os_mutex_destroy(&heap->lock);
     memset(heap->base_addr, 0, heap->max_size);
     memset(heap, 0, sizeof(gc_heap_t));
     return GC_SUCCESS;
 }
 
-#if defined(GC_VERIFY)
-/* Verify heap integrity*/
-/* @heap should not be NULL and it should be a valid heap*/
-void gci_verify_heap(gc_heap_t *heap)
+#if BH_ENABLE_GC_VERIFY != 0
+void
+gci_verify_heap(gc_heap_t *heap)
 {
     hmu_t *cur = NULL, *end = NULL;
 
@@ -151,9 +105,9 @@ void gci_verify_heap(gc_heap_t *heap)
 }
 #endif
 
-void* gc_heap_stats(void *heap_arg, uint32* stats, int size, gc_mm_t mmt)
+void *
+gc_heap_stats(void *heap_arg, uint32* stats, int size)
 {
-    (void) mmt;
     int i;
     gc_heap_t *heap = (gc_heap_t *) heap_arg;
 
@@ -168,15 +122,10 @@ void* gc_heap_stats(void *heap_arg, uint32* stats, int size, gc_mm_t mmt)
         case GC_STAT_HIGHMARK:
             stats[i] = heap->highmark_size;
             break;
-        case GC_STAT_COUNT:
-            stats[i] = heap->total_gc_count;
-            break;
-        case GC_STAT_TIME:
-            stats[i] = (uint32)heap->total_gc_time;
-            break;
         default:
             break;
         }
     }
     return heap;
 }
+
diff --git a/core/shared/mem-alloc/mem_alloc.c b/core/shared/mem-alloc/mem_alloc.c
index ee29312baa..183b16f033 100644
--- a/core/shared/mem-alloc/mem_alloc.c
+++ b/core/shared/mem-alloc/mem_alloc.c
@@ -22,19 +22,19 @@ void mem_allocator_destroy(mem_allocator_t allocator)
 void *
 mem_allocator_malloc(mem_allocator_t allocator, uint32_t size)
 {
-    return gc_alloc_vo_h((gc_handle_t) allocator, size);
+    return gc_alloc_vo((gc_handle_t) allocator, size);
 }
 
 void *
 mem_allocator_realloc(mem_allocator_t allocator, void *ptr, uint32_t size)
 {
-    return gc_realloc_vo_h((gc_handle_t) allocator, ptr, size);
+    return gc_realloc_vo((gc_handle_t) allocator, ptr, size);
 }
 
 void mem_allocator_free(mem_allocator_t allocator, void *ptr)
 {
     if (ptr)
-        gc_free_h((gc_handle_t) allocator, ptr);
+        gc_free_vo((gc_handle_t) allocator, ptr);
 }
 
 #else /* else of DEFAULT_MEM_ALLOCATOR */
diff --git a/doc/port_wamr.md b/doc/port_wamr.md
index afa762a1e5..44ac50ece5 100644
--- a/doc/port_wamr.md
+++ b/doc/port_wamr.md
@@ -3,14 +3,14 @@ WAMR porting guide
 =========================
 
 
-This document describes how to port WAMR to a new platform "**super-os**"
+This document describes how to port WAMR to a new platform "**new-os**"
 
 
 
 # Step 1: Implement platform API layer
 
 -------------------------
-Firstly create the folder **`core/shared/platform/super-os`** for platform API layer implementations. In the folder you just created, you must provide the following files:
+Firstly create the folder **`core/shared/platform/new-os`** for platform API layer implementations. In the folder you just created, you must provide the following files:
 
 - `platform_internal.h`: It can be used for any platform specific definitions such as macros, data types and internal APIs.
 
@@ -42,11 +42,11 @@ Some platforms such as ZephyrOS don't provide math functions e.g. sqrt, fabs and
 # Step 2: Create the mini product for the platform
 
 -------------------------
-You can build a mini WAMR product which is only the vmcore for you platform. Normally you need to implement the main function which loads a WASM file and run it with the WASM runtime. You don't have to do this step if there is no such need for your platform.
+You can build a mini WAMR product which is only the vmcore for you platform. Normally you need to implement the main function which loads a WASM file and run it with the WASM runtime. You don't have to do this step if there is no mini-product need for your platform porting.
 
 
 
-Firstly create folder **product-mini/platforms/super-os** for the platform mini product build, then refer to the linux platform mini-product for creating the CMakeList.txt and the C implementations.
+Firstly create folder **product-mini/platforms/new-os** for the platform mini product build, then refer to the linux platform mini-product for creating the CMakeList.txt and the C implementations.