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[mc] Use reference to types intead of type IDs
[simgrid.git] / src / xbt / mmalloc / mm_diff.c
index c681d8b..a17a4a3 100644 (file)
@@ -136,10 +136,12 @@ typedef char* type_name;
 struct s_mm_diff {
   void *s_heap, *heapbase1, *heapbase2;
   malloc_info *heapinfo1, *heapinfo2;
-  size_t heaplimit, heapsize1, heapsize2;
+  size_t heaplimit;
+  // Number of blocks in the heaps:
+  size_t heapsize1, heapsize2;
   xbt_dynar_t to_ignore1, to_ignore2;
   heap_area_t **equals_to1, **equals_to2;
-  type_name **types1, **types2;
+  dw_type_t **types1, **types2;
 };
 
 __thread struct s_mm_diff* mm_diff_info = NULL;
@@ -296,6 +298,13 @@ static void match_equals(struct s_mm_diff *state, xbt_dynar_t list){
   }
 }
 
+/** Check whether two blocks are known to be matching
+ *
+ *  @param state  State used
+ *  @param b1     Block of state 1
+ *  @param b2     Block of state 2
+ *  @return       if the blocks are known to be matching
+ */
 static int equal_blocks(struct s_mm_diff *state, int b1, int b2){
   
   if(state->equals_to1[b1][0]->block == b2 && state->equals_to2[b2][0]->block == b1)
@@ -304,6 +313,15 @@ static int equal_blocks(struct s_mm_diff *state, int b1, int b2){
   return 0;
 }
 
+/** Check whether two fragments are known to be matching
+ *
+ *  @param state  State used
+ *  @param b1     Block of state 1
+ *  @param f1     Fragment of state 1
+ *  @param b2     Block of state 2
+ *  @param f2     Fragment of state 2
+ *  @return       if the fragments are known to be matching
+ */
 static int equal_fragments(struct s_mm_diff *state, int b1, int f1, int b2, int f2){
   
   if(state->equals_to1[b1][f1]->block == b2
@@ -385,9 +403,7 @@ void reset_heap_information(){
       state->equals_to1[i][j] = NULL;
       heap_area_free(state->equals_to2[i][j]);
       state-> equals_to2[i][j] = NULL;
-      xbt_free(state->types1[i][j]);
       state->types1[i][j] = NULL;
-      xbt_free(state->types2[i][j]);
       state->types2[i][j] = NULL;
     }
     free(state->equals_to1[i]);
@@ -410,7 +426,7 @@ void reset_heap_information(){
 
 }
 
-int mmalloc_compare_heap(xbt_mheap_t heap1, xbt_mheap_t heap2, mc_object_info_t info, mc_object_info_t other_info){
+int mmalloc_compare_heap(mc_snapshot_t snapshot1, mc_snapshot_t snapshot2, xbt_mheap_t heap1, xbt_mheap_t heap2){
 
   struct s_mm_diff *state = mm_diff_info;
 
@@ -468,7 +484,7 @@ int mmalloc_compare_heap(xbt_mheap_t heap1, xbt_mheap_t heap2, mc_object_info_t
 
           addr_block2 = ((void*) (((ADDR2UINT(i1)) - 1) * BLOCKSIZE + (char*)((xbt_mheap_t)state->s_heap)->heapbase));
         
-          res_compare = compare_heap_area(addr_block1, addr_block2, NULL, info, other_info, NULL, 0);
+          res_compare = compare_heap_area(addr_block1, addr_block2, snapshot1, snapshot2, NULL, NULL, 0);
         
           if(res_compare != 1){
             for(k=1; k < state->heapinfo2[i1].busy_block.size; k++)
@@ -504,7 +520,7 @@ int mmalloc_compare_heap(xbt_mheap_t heap1, xbt_mheap_t heap2, mc_object_info_t
           continue;
         }
           
-        res_compare = compare_heap_area(addr_block1, addr_block2, NULL, info, other_info, NULL, 0);
+        res_compare = compare_heap_area(addr_block1, addr_block2, snapshot1, snapshot2, NULL, NULL, 0);
         
         if(res_compare != 1 ){
           for(k=1; k < state->heapinfo2[i2].busy_block.size; k++)
@@ -551,7 +567,7 @@ int mmalloc_compare_heap(xbt_mheap_t heap1, xbt_mheap_t heap2, mc_object_info_t
             addr_block2 = ((void*) (((ADDR2UINT(i1)) - 1) * BLOCKSIZE + (char*)((xbt_mheap_t)state->s_heap)->heapbase));
             addr_frag2 = (void*) ((char *)addr_block2 + (j1 << ((xbt_mheap_t)state->s_heap)->heapinfo[i1].type));
 
-            res_compare = compare_heap_area(addr_frag1, addr_frag2, NULL, info, other_info, NULL, 0);
+            res_compare = compare_heap_area(addr_frag1, addr_frag2, snapshot1, snapshot2, NULL, NULL, 0);
 
             if(res_compare !=  1)
               equal = 1;
@@ -580,7 +596,7 @@ int mmalloc_compare_heap(xbt_mheap_t heap1, xbt_mheap_t heap2, mc_object_info_t
             addr_block2 = ((void*) (((ADDR2UINT(i2)) - 1) * BLOCKSIZE + (char*)((xbt_mheap_t)state->s_heap)->heapbase));
             addr_frag2 = (void*) ((char *)addr_block2 + (j2 <<((xbt_mheap_t)state->s_heap)->heapinfo[i2].type));
 
-            res_compare = compare_heap_area(addr_frag1, addr_frag2, NULL, info, other_info, NULL, 0);
+            res_compare = compare_heap_area(addr_frag1, addr_frag2, snapshot2, snapshot2, NULL, NULL, 0);
             
             if(res_compare != 1){
               equal = 1;
@@ -704,7 +720,20 @@ int mmalloc_compare_heap(xbt_mheap_t heap1, xbt_mheap_t heap2, mc_object_info_t
   return ((nb_diff1 > 0) || (nb_diff2 > 0));
 }
 
-static int compare_heap_area_without_type(struct s_mm_diff *state, void *real_area1, void *real_area2, void *area1, void *area2, xbt_dynar_t previous, mc_object_info_t info, mc_object_info_t other_info, int size, int check_ignore){
+/**
+ *
+ * @param state
+ * @param real_area1     Process address for state 1
+ * @param real_area2     Process address for state 2
+ * @param area1          Snapshot address for state 1
+ * @param area2          Snapshot address for state 2
+ * @param snapshot1      Snapshot of state 1
+ * @param snapshot2      Snapshot of state 2
+ * @param previous
+ * @param size
+ * @param check_ignore
+ */
+static int compare_heap_area_without_type(struct s_mm_diff *state, void *real_area1, void *real_area2, void *area1, void *area2, mc_snapshot_t snapshot1, mc_snapshot_t snapshot2, xbt_dynar_t previous, int size, int check_ignore){
 
   int i = 0;
   void *addr_pointed1, *addr_pointed2;
@@ -739,7 +768,7 @@ static int compare_heap_area_without_type(struct s_mm_diff *state, void *real_ar
         continue;
       }else if((addr_pointed1 > state->s_heap) && ((char *)addr_pointed1 < (char *)state->s_heap + STD_HEAP_SIZE)
                && (addr_pointed2 > state->s_heap) && ((char *)addr_pointed2 < (char *)state->s_heap + STD_HEAP_SIZE)){
-        res_compare = compare_heap_area(addr_pointed1, addr_pointed2, previous, info, other_info, NULL, 0);
+        res_compare = compare_heap_area(addr_pointed1, addr_pointed2, snapshot1, snapshot2, previous, NULL, 0);
         if(res_compare == 1){
           return res_compare;
         }
@@ -759,9 +788,25 @@ static int compare_heap_area_without_type(struct s_mm_diff *state, void *real_ar
  
 }
 
-// area_size is either a byte_size or an elements_count?&
+/**
+ *
+ * @param state
+ * @param real_area1     Process address for state 1
+ * @param real_area2     Process address for state 2
+ * @param area1          Snapshot address for state 1
+ * @param area2          Snapshot address for state 2
+ * @param snapshot1      Snapshot of state 1
+ * @param snapshot2      Snapshot of state 2
+ * @param previous
+ * @param type_id
+ * @param area_size      either a byte_size or an elements_count (?)
+ * @param check_ignore
+ * @param pointer_level
+ * @return               0 (same), 1 (different), -1 (unknown)
+ */
 static int compare_heap_area_with_type(struct s_mm_diff *state, void *real_area1, void *real_area2, void *area1, void *area2,
-                                       xbt_dynar_t previous, mc_object_info_t info, mc_object_info_t other_info, char *type_id,
+                                       mc_snapshot_t snapshot1, mc_snapshot_t snapshot2,
+                                       xbt_dynar_t previous, dw_type_t type,
                                        int area_size, int check_ignore, int pointer_level){
 
   if(is_stack(real_area1) && is_stack(real_area2))
@@ -773,9 +818,8 @@ static int compare_heap_area_with_type(struct s_mm_diff *state, void *real_area1
     return 0;
   }
   
-  dw_type_t type = xbt_dict_get_or_null(info->types, type_id);
   dw_type_t subtype, subsubtype;
-  int res, elm_size, i, switch_types = 0;
+  int res, elm_size, i;
   unsigned int cursor = 0;
   dw_type_t member;
   void *addr_pointed1, *addr_pointed2;;
@@ -807,10 +851,10 @@ static int compare_heap_area_with_type(struct s_mm_diff *state, void *real_area1
   case DW_TAG_typedef:
   case DW_TAG_const_type:
   case DW_TAG_volatile_type:
-    return compare_heap_area_with_type(state, real_area1, real_area2, area1, area2, previous, info, other_info, type->dw_type_id, area_size, check_ignore, pointer_level);
+    return compare_heap_area_with_type(state, real_area1, real_area2, area1, area2, snapshot1, snapshot2, previous, type->subtype, area_size, check_ignore, pointer_level);
     break;
   case DW_TAG_array_type:
-    subtype = xbt_dict_get_or_null(info->types, type->dw_type_id);
+    subtype = type->subtype;
     switch(subtype->type){
     case DW_TAG_unspecified_type:
       return 1;
@@ -823,10 +867,8 @@ static int compare_heap_area_with_type(struct s_mm_diff *state, void *real_area1
     case DW_TAG_structure_type:
     case DW_TAG_class_type:
     case DW_TAG_union_type:
-      if(subtype->byte_size == 0){ /*declaration of the type, need the complete description */
-          subtype = xbt_dict_get_or_null(other_info->types_by_name, subtype->name);
-          switch_types = 1;
-      }
+      if(subtype->full_type)
+        subtype = subtype->full_type;
       elm_size = subtype->byte_size;
       break;
     // TODO, just remove the type indirection?
@@ -834,10 +876,8 @@ static int compare_heap_area_with_type(struct s_mm_diff *state, void *real_area1
     case DW_TAG_typedef:
     case DW_TAG_volatile_type:
       subsubtype = subtype->subtype;
-      if(subsubtype->byte_size == 0){ /*declaration of the type, need the complete description */
-          subsubtype = xbt_dict_get_or_null(other_info->types_by_name, subtype->name);
-          switch_types = 1;
-      }
+      if(subsubtype->full_type)
+        subsubtype = subsubtype->full_type;
       elm_size = subsubtype->byte_size;
       break;
     default : 
@@ -846,10 +886,7 @@ static int compare_heap_area_with_type(struct s_mm_diff *state, void *real_area1
     }
     for(i=0; i<type->element_count; i++){
       // TODO, add support for variable stride (DW_AT_byte_stride)
-      if(switch_types)
-        res = compare_heap_area_with_type(state, (char *)real_area1 + (i*elm_size), (char *)real_area2 + (i*elm_size), (char *)area1 + (i*elm_size), (char *)area2 + (i*elm_size), previous, other_info, info, type->dw_type_id, subtype->byte_size, check_ignore, pointer_level);
-      else
-        res = compare_heap_area_with_type(state, (char *)real_area1 + (i*elm_size), (char *)real_area2 + (i*elm_size), (char *)area1 + (i*elm_size), (char *)area2 + (i*elm_size), previous, info, other_info, type->dw_type_id, subtype->byte_size, check_ignore, pointer_level);
+      res = compare_heap_area_with_type(state, (char *)real_area1 + (i*elm_size), (char *)real_area2 + (i*elm_size), (char *)area1 + (i*elm_size), (char *)area2 + (i*elm_size), snapshot1, snapshot2, previous, type->subtype, subtype->byte_size, check_ignore, pointer_level);
       if(res == 1)
         return res;
     }
@@ -857,7 +894,7 @@ static int compare_heap_area_with_type(struct s_mm_diff *state, void *real_area1
   case DW_TAG_reference_type:
   case DW_TAG_rvalue_reference_type:
   case DW_TAG_pointer_type:
-    if(type->dw_type_id && ((dw_type_t)xbt_dict_get_or_null(info->types, type->dw_type_id))->type == DW_TAG_subroutine_type){
+    if(type->subtype && type->subtype->type == DW_TAG_subroutine_type){
       addr_pointed1 = *((void **)(area1)); 
       addr_pointed2 = *((void **)(area2));
       return (addr_pointed1 != addr_pointed2);;
@@ -868,7 +905,7 @@ static int compare_heap_area_with_type(struct s_mm_diff *state, void *real_area1
           addr_pointed1 = *((void **)((char *)area1 + (i*sizeof(void *)))); 
           addr_pointed2 = *((void **)((char *)area2 + (i*sizeof(void *)))); 
           if(addr_pointed1 > state->s_heap && (char *)addr_pointed1 < (char*) state->s_heap + STD_HEAP_SIZE && addr_pointed2 > state->s_heap && (char *)addr_pointed2 < (char*) state->s_heap + STD_HEAP_SIZE)
-            res =  compare_heap_area(addr_pointed1, addr_pointed2, previous, info, other_info, type->dw_type_id, pointer_level);
+            res =  compare_heap_area(addr_pointed1, addr_pointed2, snapshot1, snapshot2, previous, type->subtype, pointer_level);
           else
             res =  (addr_pointed1 != addr_pointed2);
           if(res == 1)
@@ -878,7 +915,7 @@ static int compare_heap_area_with_type(struct s_mm_diff *state, void *real_area1
         addr_pointed1 = *((void **)(area1)); 
         addr_pointed2 = *((void **)(area2));
         if(addr_pointed1 > state->s_heap && (char *)addr_pointed1 < (char*) state->s_heap + STD_HEAP_SIZE && addr_pointed2 > state->s_heap && (char *)addr_pointed2 < (char*) state->s_heap + STD_HEAP_SIZE)
-          return compare_heap_area(addr_pointed1, addr_pointed2, previous, info, other_info, type->dw_type_id, pointer_level);
+          return compare_heap_area(addr_pointed1, addr_pointed2, snapshot1, snapshot2, previous, type->subtype, pointer_level);
         else
           return  (addr_pointed1 != addr_pointed2);
       }
@@ -886,22 +923,12 @@ static int compare_heap_area_with_type(struct s_mm_diff *state, void *real_area1
     break;
   case DW_TAG_structure_type:
   case DW_TAG_class_type:
-    if(type->byte_size == 0){ /*declaration of the structure, need the complete description */
-      dw_type_t full_type = xbt_dict_get_or_null(info->types_by_name, type->name);
-      if(full_type){
-        type = full_type;
-      }else{
-        type = xbt_dict_get_or_null(other_info->types_by_name, type->name);
-        switch_types = 1;
-      }
-    }
+    if(type->full_type)
+      type = type->full_type;
     if(area_size != -1 && type->byte_size != area_size){
       if(area_size>type->byte_size && area_size%type->byte_size == 0){
         for(i=0; i<(area_size/type->byte_size); i++){
-          if(switch_types)
-            res = compare_heap_area_with_type(state, (char *)real_area1 + (i*type->byte_size), (char *)real_area2 + (i*type->byte_size), (char *)area1 + (i*type->byte_size), (char *)area2 + (i*type->byte_size), previous, other_info, info, type_id, -1, check_ignore, 0);
-          else
-            res = compare_heap_area_with_type(state, (char *)real_area1 + (i*type->byte_size), (char *)real_area2 + (i*type->byte_size), (char *)area1 + (i*type->byte_size), (char *)area2 + (i*type->byte_size), previous, info, other_info, type_id, -1, check_ignore, 0);
+          res = compare_heap_area_with_type(state, (char *)real_area1 + (i*type->byte_size), (char *)real_area2 + (i*type->byte_size), (char *)area1 + (i*type->byte_size), (char *)area2 + (i*type->byte_size), snapshot1, snapshot2, previous, type, -1, check_ignore, 0);
           if(res == 1)
             return res;
         }
@@ -910,11 +937,13 @@ static int compare_heap_area_with_type(struct s_mm_diff *state, void *real_area1
       }
     }else{
       cursor = 0;
-      xbt_dynar_foreach(type->members, cursor, member){ 
-        if(switch_types)
-          res = compare_heap_area_with_type(state, (char *)real_area1 + member->offset, (char *)real_area2 + member->offset, (char *)area1 + member->offset, (char *)area2 + member->offset, previous, other_info, info, member->dw_type_id, -1, check_ignore, 0);
-        else
-          res = compare_heap_area_with_type(state, (char *)real_area1 + member->offset, (char *)real_area2 + member->offset, (char *)area1 + member->offset, (char *)area2 + member->offset, previous, info, other_info, member->dw_type_id, -1, check_ignore, 0);
+      xbt_dynar_foreach(type->members, cursor, member){
+        // TODO, optimize this? (for the offset case)
+        char* real_member1 = mc_member_resolve(real_area1, type, member, snapshot1);
+        char* real_member2 = mc_member_resolve(real_area2, type, member, snapshot2);
+        char* member1 = mc_translate_address((uintptr_t)real_member1, snapshot1);
+        char* member2 = mc_translate_address((uintptr_t)real_member2, snapshot2);
+        res = compare_heap_area_with_type(state, real_member1, real_member2, member1, member2, snapshot1, snapshot2, previous, member->subtype, -1, check_ignore, 0);
         if(res == 1){
           return res;
         }
@@ -922,7 +951,7 @@ static int compare_heap_area_with_type(struct s_mm_diff *state, void *real_area1
     }
     break;
   case DW_TAG_union_type:
-    return compare_heap_area_without_type(state, real_area1, real_area2, area1, area2, previous, info, other_info, type->byte_size, check_ignore);
+    return compare_heap_area_without_type(state, real_area1, real_area2, area1, area2, snapshot1, snapshot2, previous, type->byte_size, check_ignore);
     break;
   default:
     break;
@@ -932,46 +961,48 @@ static int compare_heap_area_with_type(struct s_mm_diff *state, void *real_area1
 
 }
 
-static char* get_offset_type(char* type_id, int offset, mc_object_info_t info, mc_object_info_t other_info, int area_size, int *switch_type){
-  dw_type_t type = xbt_dict_get_or_null(info->types, type_id);
-  if(type == NULL){
-    type = xbt_dict_get_or_null(other_info->types, type_id);
-    *switch_type = 1;
-  }
+/** Infer the type of a part of the block from the type of the block
+ *
+ * TODO, handle DW_TAG_array_type as well as arrays of the object ((*p)[5], p[5])
+ *
+ * TODO, handle subfields ((*p).bar.foo, (*p)[5].bar…)
+ *
+ * @param  type_id            DWARF type ID of the root address
+ * @param  area_size
+ * @return                    DWARF type ID for given offset
+ */
+static dw_type_t get_offset_type(void* real_base_address, dw_type_t type, int offset, int area_size, mc_snapshot_t snapshot){
+
+  // Beginning of the block, the infered variable type if the type of the block:
+  if(offset==0)
+    return type;
+
   switch(type->type){
   case DW_TAG_structure_type :
   case DW_TAG_class_type:
-    if(type->byte_size == 0){ /*declaration of the structure, need the complete description */
-      if(*switch_type == 0){
-        dw_type_t full_type = xbt_dict_get_or_null(info->types_by_name, type->name);
-        if(full_type){
-          type = full_type;
-        }else{
-          type = xbt_dict_get_or_null(other_info->types_by_name, type->name);
-          *switch_type = 1;
-        }
-      }else{
-        dw_type_t full_type = xbt_dict_get_or_null(other_info->types_by_name, type->name);
-        if(full_type){
-          type = full_type;
-        }else{
-          type = xbt_dict_get_or_null(info->types_by_name, type->name);
-          *switch_type = 0;
-        }
-      }
+    if(type->full_type)
+      type = type->full_type;
     
-    }
     if(area_size != -1 && type->byte_size != area_size){
       if(area_size>type->byte_size && area_size%type->byte_size == 0)
-        return type_id;
+        return type;
       else
         return NULL;
     }else{
       unsigned int cursor = 0;
       dw_type_t member;
       xbt_dynar_foreach(type->members, cursor, member){ 
-        if(member->offset == offset)
-          return member->dw_type_id;
+
+        if(!member->location.size) {
+          // We have the offset, use it directly (shortcut):
+          if(member->offset == offset)
+            return member->subtype;
+        } else {
+          char* real_member = mc_member_resolve(real_base_address, type, member, snapshot);
+          if(real_member - (char*)real_base_address == offset)
+            return member->subtype;
+        }
+
       }
       return NULL;
     }
@@ -983,7 +1014,18 @@ static char* get_offset_type(char* type_id, int offset, mc_object_info_t info, m
   }
 }
 
-int compare_heap_area(void *area1, void* area2, xbt_dynar_t previous, mc_object_info_t info, mc_object_info_t other_info, char *type_id, int pointer_level){
+/**
+ *
+ * @param area1          Process address for state 1
+ * @param area2          Process address for state 2
+ * @param snapshot1      Snapshot of state 1
+ * @param snapshot2      Snapshot of state 2
+ * @param previous       Pairs of blocks already compared on the current path (or NULL)
+ * @param type_id        Type of variable
+ * @param pointer_level
+ * @return 0 (same), 1 (different), -1
+ */
+int compare_heap_area(void *area1, void* area2, mc_snapshot_t snapshot1, mc_snapshot_t snapshot2, xbt_dynar_t previous, dw_type_t type, int pointer_level){
 
   struct s_mm_diff* state = mm_diff_info;
 
@@ -994,12 +1036,10 @@ int compare_heap_area(void *area1, void* area2, xbt_dynar_t previous, mc_object_
 
   void *addr_block1, *addr_block2, *addr_frag1, *addr_frag2, *real_addr_block1, *real_addr_block2,  *real_addr_frag1, *real_addr_frag2;
   void *area1_to_compare, *area2_to_compare;
-  dw_type_t type = NULL;
   int type_size = -1;
   int offset1 =0, offset2 = 0;
   int new_size1 = -1, new_size2 = -1;
-  char *new_type_id1 = NULL, *new_type_id2 = NULL;
-  int switch_type = 0;
+  dw_type_t new_type1 = NULL, new_type2 = NULL;
 
   int match_pairs = 0;
 
@@ -1008,9 +1048,11 @@ int compare_heap_area(void *area1, void* area2, xbt_dynar_t previous, mc_object_
     match_pairs = 1;
   }
 
+  // Get block number:
   block1 = ((char*)area1 - (char*)((xbt_mheap_t)state->s_heap)->heapbase) / BLOCKSIZE + 1;
   block2 = ((char*)area2 - (char*)((xbt_mheap_t)state->s_heap)->heapbase) / BLOCKSIZE + 1;
 
+  // If either block is a stack block:
   if(is_block_stack((int)block1) && is_block_stack((int)block2)){
     add_heap_area_pair(previous, block1, -1, block2, -1);
     if(match_pairs){
@@ -1020,36 +1062,38 @@ int compare_heap_area(void *area1, void* area2, xbt_dynar_t previous, mc_object_
     return 0;
   }
 
-  if(((char *)area1 < (char*)((xbt_mheap_t)state->s_heap)->heapbase)  || (block1 > state->heapsize1) || (block1 < 1) || ((char *)area2 < (char*)((xbt_mheap_t)state->s_heap)->heapbase) || (block2 > state->heapsize2) || (block2 < 1)){
+  // If either block is not in the expected area of memory:
+  if(((char *)area1 < (char*)((xbt_mheap_t)state->s_heap)->heapbase)  || (block1 > state->heapsize1) || (block1 < 1)
+    || ((char *)area2 < (char*)((xbt_mheap_t)state->s_heap)->heapbase) || (block2 > state->heapsize2) || (block2 < 1)){
     if(match_pairs){
       xbt_dynar_free(&previous);
     }
     return 1;
   }
 
+  // Snapshot address of the block:
   addr_block1 = ((void*) (((ADDR2UINT(block1)) - 1) * BLOCKSIZE + (char*)state->heapbase1));
   addr_block2 = ((void*) (((ADDR2UINT(block2)) - 1) * BLOCKSIZE + (char*)state->heapbase2));
 
+  // Process address of the block:
   real_addr_block1 = ((void*) (((ADDR2UINT(block1)) - 1) * BLOCKSIZE + (char*)((xbt_mheap_t)state->s_heap)->heapbase));
   real_addr_block2 = ((void*) (((ADDR2UINT(block2)) - 1) * BLOCKSIZE + (char*)((xbt_mheap_t)state->s_heap)->heapbase));
 
-  if(type_id){
-    type = xbt_dict_get_or_null(info->types, type_id);
-    if(type->byte_size == 0){
-      if(type->subtype == NULL){
-        dw_type_t full_type = xbt_dict_get_or_null(info->types_by_name, type->name);
-        if(full_type)
-          type = full_type;
-        else
-          type = xbt_dict_get_or_null(other_info->types_by_name, type->name);
-      }else{
-        type = type->subtype;
-      }
-    }
+  if(type){
+
+    if(type->full_type)
+      type = type->full_type;
+
+    // This assume that for "boring" types (volatile ...) byte_size is absent:
+    while(type->byte_size == 0 && type->subtype!=NULL)
+      type = type->subtype;
+
+    // Find type_size:
     if((type->type == DW_TAG_pointer_type) || ((type->type == DW_TAG_base_type) && type->name!=NULL && (!strcmp(type->name, "char"))))
       type_size = -1;
     else
       type_size = type->byte_size;
+
   }
   
   if((state->heapinfo1[block1].type == -1) && (state->heapinfo2[block2].type == -1)){  /* Free block */
@@ -1062,6 +1106,8 @@ int compare_heap_area(void *area1, void* area2, xbt_dynar_t previous, mc_object_
 
   }else if((state->heapinfo1[block1].type == 0) && (state->heapinfo2[block2].type == 0)){ /* Complete block */
     
+    // TODO, lookup variable type from block type as done for fragmented blocks
+
     if(state->equals_to1[block1][0] != NULL && state->equals_to2[block2][0] != NULL){
       if(equal_blocks(state, block1, block2)){
         if(match_pairs){
@@ -1108,11 +1154,15 @@ int compare_heap_area(void *area1, void* area2, xbt_dynar_t previous, mc_object_
  
     size = state->heapinfo1[block1].busy_block.busy_size;
     
-    if(type_id != NULL){
+    // Remember (basic) type inference.
+    // The current data structure only allows us to do this for the whole block.
+    if (type != NULL && area1==real_addr_block1) {
       xbt_free(state->types1[block1][0]);
+      state->types1[block1][0] = type;
+    }
+    if (type != NULL && area2==real_addr_block2) {
       xbt_free(state->types2[block2][0]);
-      state->types1[block1][0] = strdup(type_id);
-      state->types2[block2][0] = strdup(type_id);
+      state->types2[block2][0] = type;
     }
 
     if(size <= 0){
@@ -1134,15 +1184,19 @@ int compare_heap_area(void *area1, void* area2, xbt_dynar_t previous, mc_object_
       
   }else if((state->heapinfo1[block1].type > 0) && (state->heapinfo2[block2].type > 0)){ /* Fragmented block */
 
+    // Fragment number:
     frag1 = ((uintptr_t) (ADDR2UINT (area1) % (BLOCKSIZE))) >> state->heapinfo1[block1].type;
     frag2 = ((uintptr_t) (ADDR2UINT (area2) % (BLOCKSIZE))) >> state->heapinfo2[block2].type;
 
+    // Snapshot address of the fragment:
     addr_frag1 = (void*) ((char *)addr_block1 + (frag1 << state->heapinfo1[block1].type));
     addr_frag2 = (void*) ((char *)addr_block2 + (frag2 << state->heapinfo2[block2].type));
 
+    // Process address of the fragment:
     real_addr_frag1 = (void*) ((char *)real_addr_block1 + (frag1 << ((xbt_mheap_t)state->s_heap)->heapinfo[block1].type));
     real_addr_frag2 = (void*) ((char *)real_addr_block2 + (frag2 << ((xbt_mheap_t)state->s_heap)->heapinfo[block2].type));
 
+    // Check the size of the fragments against the size of the type:
     if(type_size != -1){
       if(state->heapinfo1[block1].busy_frag.frag_size[frag1] == -1 || state->heapinfo2[block2].busy_frag.frag_size[frag2] == -1){
         if(match_pairs){
@@ -1160,6 +1214,7 @@ int compare_heap_area(void *area1, void* area2, xbt_dynar_t previous, mc_object_
       }
     }
 
+    // Check if the blocks are already matched together:
     if(state->equals_to1[block1][frag1] != NULL && state->equals_to2[block2][frag2] != NULL){
       if(equal_fragments(state, block1, frag1, block2, frag2)){
         if(match_pairs){
@@ -1170,6 +1225,7 @@ int compare_heap_area(void *area1, void* area2, xbt_dynar_t previous, mc_object_
       }
     }
 
+    // Compare the size of both fragments:
     if(state->heapinfo1[block1].busy_frag.frag_size[frag1] != state->heapinfo2[block2].busy_frag.frag_size[frag2]){
       if(type_size == -1){
          if(match_pairs){
@@ -1185,27 +1241,39 @@ int compare_heap_area(void *area1, void* area2, xbt_dynar_t previous, mc_object_
       }
     }
       
+    // Size of the fragment:
     size = state->heapinfo1[block1].busy_frag.frag_size[frag1];
 
-    if(type_id != NULL){
-      xbt_free(state->types1[block1][frag1]);
-      xbt_free(state->types2[block2][frag2]);
-      state->types1[block1][frag1] = strdup(type_id);
-      state->types2[block2][frag2] = strdup(type_id);
+    // Remember (basic) type inference.
+    // The current data structure only allows us to do this for the whole block.
+    if(type != NULL && area1==real_addr_frag1){
+      state->types1[block1][frag1] = type;
+    }
+    if(type != NULL && area2==real_addr_frag2) {
+      state->types2[block2][frag2] = type;
+    }
+
+    // The type of the variable is already known:
+    if(type) {
+      new_type1 = type;
+      new_type2 = type;
     }
 
-    if(real_addr_frag1 != area1 || real_addr_frag2 != area2){
+    // Type inference from the block type.
+    else if(state->types1[block1][frag1] != NULL || state->types2[block2][frag2] != NULL) {
+
       offset1 = (char *)area1 - (char *)real_addr_frag1;
       offset2 = (char *)area2 - (char *)real_addr_frag2;
+
       if(state->types1[block1][frag1] != NULL && state->types2[block2][frag2] != NULL){
-        new_type_id1 = get_offset_type(state->types1[block1][frag1], offset1, info, other_info, size, &switch_type);
-        new_type_id2 = get_offset_type(state->types2[block2][frag2], offset1, info, other_info, size, &switch_type);
+        new_type1 = get_offset_type(real_addr_frag1, state->types1[block1][frag1], offset1, size, snapshot1);
+        new_type2 = get_offset_type(real_addr_frag2, state->types2[block2][frag2], offset1, size, snapshot2);
       }else if(state->types1[block1][frag1] != NULL){
-        new_type_id1 = get_offset_type(state->types1[block1][frag1], offset1, info, other_info, size, &switch_type);
-        new_type_id2 = get_offset_type(state->types1[block1][frag1], offset2, info, other_info, size, &switch_type);
+        new_type1 = get_offset_type(real_addr_frag1, state->types1[block1][frag1], offset1, size, snapshot1);
+        new_type2 = get_offset_type(real_addr_frag2, state->types1[block1][frag1], offset2, size, snapshot2);
       }else if(state->types2[block2][frag2] != NULL){
-        new_type_id1 = get_offset_type(state->types2[block2][frag2], offset1, info, other_info, size, &switch_type);
-        new_type_id2 = get_offset_type(state->types2[block2][frag2], offset2, info, other_info, size, &switch_type);
+        new_type1 = get_offset_type(real_addr_frag1, state->types2[block2][frag2], offset1, size, snapshot1);
+        new_type2 = get_offset_type(real_addr_frag2, state->types2[block2][frag2], offset2, size, snapshot2);
       }else{
         if(match_pairs){
           match_equals(state, previous);
@@ -1214,26 +1282,18 @@ int compare_heap_area(void *area1, void* area2, xbt_dynar_t previous, mc_object_
         return -1;
       }   
 
-      if(new_type_id1 !=  NULL && new_type_id2 !=  NULL && !strcmp(new_type_id1, new_type_id2)){
-        if(switch_type){
-          type = xbt_dict_get_or_null(other_info->types, new_type_id1);
-          while(type->byte_size == 0 && type->dw_type_id != NULL)
-            type = xbt_dict_get_or_null(other_info->types, type->dw_type_id);
-          new_size1 = type->byte_size;
-          type = xbt_dict_get_or_null(other_info->types, new_type_id2);
-          while(type->byte_size == 0 && type->dw_type_id != NULL)
-            type = xbt_dict_get_or_null(other_info->types, type->dw_type_id);
-          new_size2 = type->byte_size;
-        }else{
-          type = xbt_dict_get_or_null(info->types, new_type_id1);
-          while(type->byte_size == 0 && type->dw_type_id != NULL)
-            type = xbt_dict_get_or_null(info->types, type->dw_type_id);
+      if(new_type1 !=  NULL && new_type2 !=  NULL && new_type1!=new_type2){
+
+          type = new_type1;
+          while(type->byte_size == 0 && type->subtype != NULL)
+            type = type->subtype;
           new_size1 = type->byte_size;
-          type = xbt_dict_get_or_null(info->types, new_type_id2);
-          while(type->byte_size == 0 && type->dw_type_id != NULL)
-            type = xbt_dict_get_or_null(info->types, type->dw_type_id);
+
+          type = new_type2;
+          while(type->byte_size == 0 && type->subtype != NULL)
+            type = type->subtype;
           new_size2 = type->byte_size;
-        }
+
       }else{
         if(match_pairs){
           match_equals(state, previous);
@@ -1247,7 +1307,7 @@ int compare_heap_area(void *area1, void* area2, xbt_dynar_t previous, mc_object_
     area2_to_compare = (char *)addr_frag2 + offset2;
     
     if(new_size1 > 0 && new_size1 == new_size2){
-      type_id = new_type_id1;
+      type = new_type1;
       size = new_size1;
     }
 
@@ -1283,26 +1343,15 @@ int compare_heap_area(void *area1, void* area2, xbt_dynar_t previous, mc_object_
   
 
   /* Start comparison*/
-  if(type_id != NULL){
-    if(switch_type)
-      res_compare = compare_heap_area_with_type(state, area1, area2, area1_to_compare, area2_to_compare, previous, other_info, info, type_id, size, check_ignore, pointer_level);
-    else
-      res_compare = compare_heap_area_with_type(state, area1, area2, area1_to_compare, area2_to_compare, previous, info, other_info, type_id, size, check_ignore, pointer_level);
-    if(res_compare == 1){
-      if(match_pairs)
-        xbt_dynar_free(&previous);
-      return res_compare;
-    }
+  if(type){
+    res_compare = compare_heap_area_with_type(state, area1, area2, area1_to_compare, area2_to_compare, snapshot1, snapshot2, previous, type, size, check_ignore, pointer_level);
   }else{
-    if(switch_type)
-      res_compare = compare_heap_area_without_type(state, area1, area2, area1_to_compare, area2_to_compare, previous, other_info, info, size, check_ignore);
-    else
-      res_compare = compare_heap_area_without_type(state, area1, area2, area1_to_compare, area2_to_compare, previous, info, other_info, size, check_ignore);
-    if(res_compare == 1){
-      if(match_pairs)
-        xbt_dynar_free(&previous);
-      return res_compare;
-    }
+    res_compare = compare_heap_area_without_type(state, area1, area2, area1_to_compare, area2_to_compare, snapshot1, snapshot2, previous, size, check_ignore);
+  }
+  if(res_compare == 1){
+    if(match_pairs)
+      xbt_dynar_free(&previous);
+    return res_compare;
   }
 
   if(match_pairs){