X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/6229ff3a39c8fb195846ea9eb67cf071654de597..c9b5c4107389722899efcee79bc56d8181a621fa:/src/mc/mc_checkpoint.c

diff --git a/src/mc/mc_checkpoint.c b/src/mc/mc_checkpoint.c
index aec3a719d1..c57a4f5750 100644
--- a/src/mc/mc_checkpoint.c
+++ b/src/mc/mc_checkpoint.c
@@ -1,25 +1,86 @@
-#include <libgen.h>
-#include "private.h"
+/* Copyright (c) 2008-2014. The SimGrid Team.
+ * All rights reserved.                                                     */
 
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+#define _GNU_SOURCE
+#define UNW_LOCAL_ONLY
+
+#include <string.h>
+#include <link.h>
+#include "mc_private.h"
+#include "xbt/module.h"
+#include <xbt/mmalloc.h>
+
+#include "xbt/mmalloc/mmprivate.h"
+
+#include "../simix/smx_private.h"
+
+#include <libunwind.h>
+#include <libelf.h>
+
+#include "mc_private.h"
 
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_checkpoint, mc,
                                 "Logging specific to mc_checkpoint");
 
-static mc_mem_region_t MC_region_new(int type, void *start_addr, size_t size);
-static void MC_region_restore(mc_mem_region_t reg);
-static void MC_region_destroy(mc_mem_region_t reg);
+char *libsimgrid_path;
+
+/************************************  Free functions **************************************/
+/*****************************************************************************************/
+
+static void MC_snapshot_stack_free(mc_snapshot_stack_t s){
+  if(s){
+    xbt_dynar_free(&(s->local_variables));
+    xbt_dynar_free(&(s->stack_frames));
+    xbt_free(s);
+  }
+}
+
+static void MC_snapshot_stack_free_voidp(void *s){
+  MC_snapshot_stack_free((mc_snapshot_stack_t) * (void **) s);
+}
+
+static void local_variable_free(local_variable_t v){
+  xbt_free(v->name);
+  xbt_free(v);
+}
+
+static void local_variable_free_voidp(void *v){
+  local_variable_free((local_variable_t) * (void **) v);
+}
+
+static void MC_region_destroy(mc_mem_region_t reg)
+{
+  xbt_free(reg->data);
+  xbt_free(reg);
+}
+
+void MC_free_snapshot(mc_snapshot_t snapshot){
+  unsigned int i;
+  for(i=0; i < NB_REGIONS; i++)
+    MC_region_destroy(snapshot->regions[i]);
 
-static void MC_snapshot_add_region(mc_snapshot_t snapshot, int type, void *start_addr, size_t size);
+  xbt_free(snapshot->stack_sizes);
+  xbt_dynar_free(&(snapshot->stacks));
+  xbt_dynar_free(&(snapshot->to_ignore));
+  xbt_free(snapshot);
+}
+
+
+/*******************************  Snapshot regions ********************************/
+/*********************************************************************************/
 
 static mc_mem_region_t MC_region_new(int type, void *start_addr, size_t size)
 {
-  mc_mem_region_t new_reg = xbt_new0(s_mc_mem_region_t, 1);
-  new_reg->type = type;
+  mc_mem_region_t new_reg = xbt_new(s_mc_mem_region_t, 1);
   new_reg->start_addr = start_addr;
   new_reg->size = size;
-  new_reg->data = xbt_malloc0(size);
-  XBT_DEBUG("New reg data %p, start_addr %p", new_reg->data, start_addr);
+  new_reg->data = xbt_malloc(size);
   memcpy(new_reg->data, start_addr, size);
+
+  XBT_DEBUG("New region : type : %d, data : %p (real addr %p), size : %zu", type, new_reg->data, start_addr, size);
   
   return new_reg;
 }
@@ -28,168 +89,432 @@ static void MC_region_restore(mc_mem_region_t reg)
 {
   /*FIXME: check if start_addr is still mapped, if it is not, then map it
     before copying the data */
-  if(reg->type == 3){
-    memory_map_t maps = get_memory_map();
-    MC_UNSET_RAW_MEM;
-    unsigned int i=0;
-    s_map_region r;
-    while(i < maps->mapsize){
-      r = maps->regions[i];
-      if (maps->regions[i].pathname != NULL){
-	if (!memcmp(maps->regions[i].pathname, "[stack]", 7)){
-	  size_t diff = (char*)reg->start_addr - (char*)r.start_addr;
-	  void *segment = malloc(reg->size + diff);
-	  XBT_DEBUG("Size of segment : %lu", sizeof(segment));
-	  memcpy((char *)segment + diff, reg->data, reg->size);
-	  //memset(segment, '\0', diff);
-	  //XBT_DEBUG("Memset ok");
-	  //memcpy(segment+diff, reg->data, reg->size);
-	  //XBT_DEBUG("Memcpy segment ok");
-	  memcpy(r.start_addr, segment, sizeof(segment));
-	  XBT_DEBUG("Memcpy region ok");
-	  //memcpy(r.start_addr, reg->data, sizeof(reg->data));
-	  break;
-	}
-      }
-      i++;
-    }
-  }else{
-    XBT_DEBUG("Memcpy : dest %p, src %p, size %Zu", reg->start_addr, reg->data, reg->size);
-    memcpy(reg->start_addr, reg->data, reg->size);
-  }
-  
-  //return;
-}
-
-static void MC_region_destroy(mc_mem_region_t reg)
-{
-  xbt_free(reg->data);
-  xbt_free(reg);
+ 
+  memcpy(reg->start_addr, reg->data, reg->size);
+  return;
 }
 
 static void MC_snapshot_add_region(mc_snapshot_t snapshot, int type, void *start_addr, size_t size)
 {
-  switch(type){
-  case 0 : 
-    XBT_DEBUG("New region heap");
-    break;
-  case 1 : 
-    XBT_DEBUG("New region libsimgrid");
-    break;
-  case 2 : 
-    XBT_DEBUG("New region program");
-    break;
-  case 3 : 
-    XBT_DEBUG("New region stack");
-    break;
-  }
   mc_mem_region_t new_reg = MC_region_new(type, start_addr, size);
-  snapshot->regions = xbt_realloc(snapshot->regions, (snapshot->num_reg + 1) * sizeof(mc_mem_region_t));
-  snapshot->regions[snapshot->num_reg] = new_reg;
-  snapshot->num_reg++;
+  snapshot->regions[type] = new_reg;
   return;
 } 
 
-void MC_take_snapshot(mc_snapshot_t snapshot)
-{
+static void MC_get_memory_regions(mc_snapshot_t snapshot){
+
+  void* start_heap = ((xbt_mheap_t)std_heap)->base;
+  void* end_heap   = ((xbt_mheap_t)std_heap)->breakval;
+  MC_snapshot_add_region(snapshot, 0, start_heap, (char*) end_heap - (char*) start_heap);
+  snapshot->heap_bytes_used = mmalloc_get_bytes_used(std_heap);
+
+  MC_snapshot_add_region(snapshot, 1,  mc_libsimgrid_info->start_rw, mc_libsimgrid_info->end_rw - mc_libsimgrid_info->start_rw);
+  MC_snapshot_add_region(snapshot, 2,  mc_binary_info->start_rw, mc_binary_info->end_rw - mc_binary_info->start_rw);
+}
+
+/** @brief Finds the range of the different memory segments and binary paths */
+void MC_init_memory_map_info(){
+ 
   unsigned int i = 0;
-  s_map_region reg;
-  memory_map_t maps = get_memory_map();
+  s_map_region_t reg;
+  memory_map_t maps = MC_get_memory_map();
+
+  maestro_stack_start = NULL;
+  maestro_stack_end = NULL;
+  libsimgrid_path = NULL;
 
-  /* Save the std heap and the writable mapped pages of libsimgrid */
   while (i < maps->mapsize) {
     reg = maps->regions[i];
-    if ((reg.prot & PROT_WRITE)){
-      if (maps->regions[i].pathname == NULL){
-        if (reg.start_addr == std_heap){ // only save the std heap (and not the raw one)
-          MC_snapshot_add_region(snapshot, 0, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
-        }
-      } else {
-        if (!memcmp(basename(maps->regions[i].pathname), "libsimgrid", 10)){
-          MC_snapshot_add_region(snapshot, 1, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
-        } 
-      }
+    if (maps->regions[i].pathname == NULL) {
+      // Nothing to do
+    }
+    else if ((reg.prot & PROT_WRITE) && !memcmp(maps->regions[i].pathname, "[stack]", 7)){
+          maestro_stack_start = reg.start_addr;
+          maestro_stack_end = reg.end_addr;
+    } else if ((reg.prot & PROT_READ) && (reg.prot & PROT_EXEC) && !memcmp(basename(maps->regions[i].pathname), "libsimgrid", 10)){
+      if(libsimgrid_path == NULL)
+          libsimgrid_path = strdup(maps->regions[i].pathname);
     }
     i++;
   }
 
-  /* FIXME: free the memory map */
+  xbt_assert(maestro_stack_start, "maestro_stack_start");
+  xbt_assert(maestro_stack_end, "maestro_stack_end");
+  xbt_assert(libsimgrid_path, "libsimgrid_path&");
+
+  MC_free_memory_map(maps);
+
 }
 
+/** \brief Fill/lookup the "subtype" field.
+ */
+static void MC_resolve_subtype(mc_object_info_t info, dw_type_t type) {
 
-void MC_take_snapshot_liveness(mc_snapshot_t snapshot, char *prgm)
-{
-  unsigned int i = 0;
-  s_map_region reg;
-  memory_map_t maps = get_memory_map();
+  if(type->dw_type_id==NULL)
+    return;
+  type->subtype = xbt_dict_get_or_null(info->types, type->dw_type_id);
+  if(type->subtype==NULL)
+    return;
+  if(type->subtype->byte_size != 0)
+    return;
+  if(type->subtype->name==NULL)
+    return;
+  // Try to find a more complete description of the type:
+  // We need to fix in order to support C++.
 
-  for(i=0; i< snapshot->num_reg; i++){
-    MC_region_destroy(snapshot->regions[i]);
+  dw_type_t subtype = xbt_dict_get_or_null(info->full_types_by_name, type->subtype->name);
+  if(subtype!=NULL) {
+    type->subtype = subtype;
   }
 
-  snapshot->num_reg = 0;
+}
+
+void MC_post_process_types(mc_object_info_t info) {
+  xbt_dict_cursor_t cursor = NULL;
+  char *origin;
+  dw_type_t type;
+
+  // Lookup "subtype" field:
+  xbt_dict_foreach(info->types, cursor, origin, type){
+    MC_resolve_subtype(info, type);
+
+    dw_type_t member;
+    unsigned int i = 0;
+    if(type->members!=NULL) xbt_dynar_foreach(type->members, i, member) {
+      MC_resolve_subtype(info, member);
+    }
+  }
+}
 
-  i = 0;
+/** \brief Fills the position of the segments (executable, read-only, read/write).
+ *
+ * TODO, use dl_iterate_phdr to be more robust
+ * */
+void MC_find_object_address(memory_map_t maps, mc_object_info_t result) {
 
-  /* Save the std heap and the writable mapped pages of libsimgrid */
+  unsigned int i = 0;
+  s_map_region_t reg;
+  const char* name = basename(result->file_name);
   while (i < maps->mapsize) {
     reg = maps->regions[i];
-    if ((reg.prot & PROT_WRITE)){
-      if (maps->regions[i].pathname == NULL){
-        if (reg.start_addr == std_heap){ // only save the std heap (and not the raw one)
-          MC_snapshot_add_region(snapshot, 0, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
-        }
-      } else {
-        if (!memcmp(basename(maps->regions[i].pathname), "libsimgrid", 10)){
-          MC_snapshot_add_region(snapshot, 1, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
-        } else {
-	  if (!memcmp(basename(maps->regions[i].pathname), basename(prgm), strlen(basename(prgm)))){
-	    MC_snapshot_add_region(snapshot, 2, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
-	  } else {
-	    if (!memcmp(maps->regions[i].pathname, "[stack]", 7)){
-	      MC_snapshot_add_region(snapshot, 3, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
-	    }
-	  }
-	}
-      }
+    if (maps->regions[i].pathname == NULL || strcmp(basename(maps->regions[i].pathname),  name)) {
+      // Nothing to do
+    }
+    else if ((reg.prot & PROT_WRITE)){
+          xbt_assert(!result->start_rw,
+            "Multiple read-write segments for %s, not supported",
+            maps->regions[i].pathname);
+          result->start_rw = reg.start_addr;
+          result->end_rw   = reg.end_addr;
+          // .bss is usually after the .data:
+          s_map_region_t* next = &(maps->regions[i+1]);
+          if(next->pathname == NULL && (next->prot & PROT_WRITE) && next->start_addr == reg.end_addr) {
+            result->end_rw = maps->regions[i+1].end_addr;
+          }
+    } else if ((reg.prot & PROT_READ) && (reg.prot & PROT_EXEC)){
+          xbt_assert(!result->start_exec,
+            "Multiple executable segments for %s, not supported",
+            maps->regions[i].pathname);
+          result->start_exec = reg.start_addr;
+          result->end_exec   = reg.end_addr;
+    }
+    else if((reg.prot & PROT_READ) && !(reg.prot & PROT_EXEC)) {
+        xbt_assert(!result->start_ro,
+          "Multiple read only segments for %s, not supported",
+          maps->regions[i].pathname);
+        result->start_ro = reg.start_addr;
+        result->end_ro   = reg.end_addr;
     }
     i++;
   }
 
-  /* FIXME: free the memory map */
+  xbt_assert(result->file_name);
+  xbt_assert(result->start_rw);
+  xbt_assert(result->start_exec);
 }
 
-void MC_restore_snapshot(mc_snapshot_t snapshot)
-{
-  unsigned int i;
-  for(i=0; i < snapshot->num_reg; i++){
-    MC_region_restore(snapshot->regions[i]);
-    switch(snapshot->regions[i]->type){
-    case 0 : 
-      XBT_DEBUG("heap restored");
-      break;
-    case 1:
-      XBT_DEBUG("libsimgrid (data) restored");
-      break;
-    case 2:
-      XBT_DEBUG("program (data) restored");
-      break;
-    case 3:
-      XBT_DEBUG("stack restored");
+/************************************* Take Snapshot ************************************/
+/****************************************************************************************/
+
+/** \brief Checks whether the variable is in scope for a given IP.
+ *
+ *  A variable may be defined only from a given value of IP.
+ *
+ *  \param var   Variable description
+ *  \param frame Scope description
+ *  \param ip    Instruction pointer
+ *  \return      true if the variable is valid
+ * */
+static bool mc_valid_variable(dw_variable_t var, dw_frame_t frame, const void* ip) {
+  // The variable is not yet valid:
+  if((const void*)((const char*) frame->low_pc + var->start_scope) > ip)
+    return false;
+  else
+    return true;
+}
+
+static void mc_fill_local_variables_values(mc_stack_frame_t stack_frame, dw_frame_t scope, xbt_dynar_t result) {
+  void* ip = (void*) stack_frame->ip;
+  if(ip < scope->low_pc || ip>= scope->high_pc)
+    return;
+
+  unsigned cursor = 0;
+  dw_variable_t current_variable;
+  xbt_dynar_foreach(scope->variables, cursor, current_variable){
+
+    if(!mc_valid_variable(current_variable, stack_frame->frame, (void*) stack_frame->ip))
+      continue;
+
+    int region_type;
+    if((long)stack_frame->ip > (long)mc_libsimgrid_info->start_exec)
+      region_type = 1;
+    else
+      region_type = 2;
+
+    local_variable_t new_var = xbt_new0(s_local_variable_t, 1);
+    new_var->subprogram = stack_frame->frame;
+    new_var->ip = stack_frame->ip;
+    new_var->name = xbt_strdup(current_variable->name);
+    new_var->type = current_variable->type;
+    new_var->region= region_type;
+
+    /* if(current_variable->address!=NULL) {
+      new_var->address = current_variable->address;
+    } else */
+    if(current_variable->locations.size != 0){
+      new_var->address = (void*) mc_dwarf_resolve_locations(&current_variable->locations,
+        &(stack_frame->unw_cursor), (void*)stack_frame->frame_base, NULL);
+    }
+
+    xbt_dynar_push(result, &new_var);
+  }
+
+  // Recursive processing of nested scopes:
+  dw_frame_t nested_scope = NULL;
+  xbt_dynar_foreach(scope->scopes, cursor, nested_scope) {
+    mc_fill_local_variables_values(stack_frame, nested_scope, result);
+  }
+}
+
+static xbt_dynar_t MC_get_local_variables_values(xbt_dynar_t stack_frames){
+
+  unsigned cursor1 = 0;
+  mc_stack_frame_t stack_frame;
+  xbt_dynar_t variables = xbt_dynar_new(sizeof(local_variable_t), local_variable_free_voidp);
+
+  xbt_dynar_foreach(stack_frames,cursor1,stack_frame) {
+    mc_fill_local_variables_values(stack_frame, stack_frame->frame, variables);
+  }
+
+  return variables;
+}
+
+static void MC_stack_frame_free_voipd(void *s){
+  mc_stack_frame_t stack_frame = *(mc_stack_frame_t*)s;
+  if(stack_frame) {
+    xbt_free(stack_frame->frame_name);
+    xbt_free(stack_frame);
+  }
+}
+
+static xbt_dynar_t MC_unwind_stack_frames(void *stack_context) {
+  xbt_dynar_t result = xbt_dynar_new(sizeof(mc_stack_frame_t), MC_stack_frame_free_voipd);
+
+  unw_cursor_t c;
+
+  int ret;
+  for(ret = unw_init_local(&c, (unw_context_t *)stack_context); ret >= 0; ret = unw_step(&c)){
+    mc_stack_frame_t stack_frame = xbt_new(s_mc_stack_frame_t, 1);
+    xbt_dynar_push(result, &stack_frame);
+
+    stack_frame->unw_cursor = c;
+
+    unw_word_t ip, sp;
+
+    unw_get_reg(&c, UNW_REG_IP, &ip);
+    unw_get_reg(&c, UNW_REG_SP, &sp);
+
+    stack_frame->ip = ip;
+    stack_frame->sp = sp;
+
+    // TODO, use real addresses in frame_t instead of fixing it here
+
+    dw_frame_t frame = MC_find_function_by_ip((void*) ip);
+    stack_frame->frame = frame;
+
+    if(frame) {
+      stack_frame->frame_name = xbt_strdup(frame->name);
+      stack_frame->frame_base = (unw_word_t)mc_find_frame_base(frame, &c);
+    } else {
+      stack_frame->frame_base = 0;
+    }
+
+    /* Stop before context switch with maestro */
+    if(frame!=NULL && frame->name!=NULL && !strcmp(frame->name, "smx_ctx_sysv_wrapper"))
       break;
+  }
+
+  if(xbt_dynar_length(result) == 0){
+    XBT_INFO("unw_init_local failed");
+    xbt_abort();
+  }
+
+  return result;
+};
+
+static xbt_dynar_t MC_take_snapshot_stacks(mc_snapshot_t *snapshot, void *heap){
+
+  xbt_dynar_t res = xbt_dynar_new(sizeof(s_mc_snapshot_stack_t), MC_snapshot_stack_free_voidp);
+
+  unsigned int cursor = 0;
+  stack_region_t current_stack;
+  
+  xbt_dynar_foreach(stacks_areas, cursor, current_stack){
+    mc_snapshot_stack_t st = xbt_new(s_mc_snapshot_stack_t, 1);
+    st->stack_frames = MC_unwind_stack_frames(current_stack->context);
+    st->local_variables = MC_get_local_variables_values(st->stack_frames);
+
+    unw_word_t sp = xbt_dynar_get_as(st->stack_frames, 0, mc_stack_frame_t)->sp;
+    st->stack_pointer = ((char *)heap + (size_t)(((char *)((long)sp) - (char*)std_heap)));
+
+    st->real_address = current_stack->address;
+    xbt_dynar_push(res, &st);
+    (*snapshot)->stack_sizes = xbt_realloc((*snapshot)->stack_sizes, (cursor + 1) * sizeof(size_t));
+    (*snapshot)->stack_sizes[cursor] = current_stack->size - ((char *)st->stack_pointer - (char *)((char *)heap + ((char *)current_stack->address - (char *)std_heap)));
+  }
+
+  return res;
+
+}
+
+static xbt_dynar_t MC_take_snapshot_ignore(){
+  
+  if(mc_heap_comparison_ignore == NULL)
+    return NULL;
+
+  xbt_dynar_t cpy = xbt_dynar_new(sizeof(mc_heap_ignore_region_t), heap_ignore_region_free_voidp);
+
+  unsigned int cursor = 0;
+  mc_heap_ignore_region_t current_region;
+
+  xbt_dynar_foreach(mc_heap_comparison_ignore, cursor, current_region){
+    mc_heap_ignore_region_t new_region = NULL;
+    new_region = xbt_new0(s_mc_heap_ignore_region_t, 1);
+    new_region->address = current_region->address;
+    new_region->size = current_region->size;
+    new_region->block = current_region->block;
+    new_region->fragment = current_region->fragment;
+    xbt_dynar_push(cpy, &new_region);
+  }
+
+  return cpy;
+
+}
+
+static void MC_dump_checkpoint_ignore(mc_snapshot_t snapshot){
+  
+  unsigned int cursor = 0;
+  mc_checkpoint_ignore_region_t region;
+  size_t offset;
+  
+  xbt_dynar_foreach(mc_checkpoint_ignore, cursor, region){
+    if(region->addr > snapshot->regions[0]->start_addr && (char *)(region->addr) < (char *)snapshot->regions[0]->start_addr + STD_HEAP_SIZE){
+      offset = (char *)region->addr - (char *)snapshot->regions[0]->start_addr;
+      memset((char *)snapshot->regions[0]->data + offset, 0, region->size);
+    }else if(region->addr > snapshot->regions[2]->start_addr && (char *)(region->addr) < (char*)snapshot->regions[2]->start_addr + snapshot->regions[2]->size){
+      offset = (char *)region->addr - (char *)snapshot->regions[2]->start_addr;
+      memset((char *)snapshot->regions[2]->data + offset, 0, region->size);
+    }else if(region->addr > snapshot->regions[1]->start_addr && (char *)(region->addr) < (char*)snapshot->regions[1]->start_addr + snapshot->regions[1]->size){
+      offset = (char *)region->addr - (char *)snapshot->regions[1]->start_addr;
+      memset((char *)snapshot->regions[1]->data + offset, 0, region->size);
     }
+  }
+
+}
+
+
+mc_snapshot_t MC_take_snapshot(int num_state){
+
+  mc_snapshot_t snapshot = xbt_new0(s_mc_snapshot_t, 1);
+  snapshot->nb_processes = xbt_swag_size(simix_global->process_list);
 
+  /* Save the std heap and the writable mapped pages of libsimgrid and binary */
+  MC_get_memory_regions(snapshot);
+
+  snapshot->to_ignore = MC_take_snapshot_ignore();
+
+  if(_sg_mc_visited > 0 || strcmp(_sg_mc_property_file,"")){
+    snapshot->stacks = MC_take_snapshot_stacks(&snapshot, snapshot->regions[0]->data);
+    if(_sg_mc_hash && snapshot->stacks!=NULL) {
+      snapshot->hash = mc_hash_processes_state(num_state, snapshot->stacks);
+    } else {
+      snapshot->hash = 0;
+    }
   }
+  else {
+    snapshot->hash = 0;
+  }
+
+  if(num_state > 0)
+    MC_dump_checkpoint_ignore(snapshot);
+
+  return snapshot;
 
 }
 
-void MC_free_snapshot(mc_snapshot_t snapshot)
-{
+void MC_restore_snapshot(mc_snapshot_t snapshot){
   unsigned int i;
-  for(i=0; i < snapshot->num_reg; i++)
-    MC_region_destroy(snapshot->regions[i]);
+  for(i=0; i < NB_REGIONS; i++){
+    MC_region_restore(snapshot->regions[i]);
+  }
 
-  xbt_free(snapshot);
 }
 
+void* mc_translate_address(uintptr_t addr, mc_snapshot_t snapshot) {
+
+  // If not in a process state/clone:
+  if(!snapshot) {
+    return (uintptr_t*) addr;
+  }
+
+  // If it is in a snapshot:
+  for(size_t i=0; i!=NB_REGIONS; ++i) {
+    mc_mem_region_t region = snapshot->regions[i];
+    uintptr_t start = (uintptr_t) region->start_addr;
+    uintptr_t end = start + region->size;
+
+    // The address is in this region:
+    if(addr >= start && addr < end) {
+      uintptr_t offset = addr - start;
+      return (void*) ((uintptr_t)region->data + offset);
+    }
+
+  }
+
+  // It is not in a snapshot:
+  return (void*) addr;
+}
+
+uintptr_t mc_untranslate_address(void* addr, mc_snapshot_t snapshot) {
+  if(!snapshot) {
+    return (uintptr_t) addr;
+  }
+
+  for(size_t i=0; i!=NB_REGIONS; ++i) {
+    mc_mem_region_t region = snapshot->regions[i];
+    if(addr>=region->data && addr<=(void*)(((char*)region->data)+region->size)) {
+      size_t offset = (size_t) ((char*) addr - (char*) region->data);
+      return ((uintptr_t) region->start_addr) + offset;
+    }
+  }
+
+  return (uintptr_t) addr;
+}
+
+mc_snapshot_t SIMIX_pre_mc_snapshot(smx_simcall_t simcall){
+  return MC_take_snapshot(1);
+}
 
+void *MC_snapshot(void){
+  return simcall_mc_snapshot();
+}