X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/66248ebaa3e1745f85dfa34c56ff0f16fb874c13..719a77db362a51309e90a75253788223936b276c:/src/mc/mc_snapshot.c

diff --git a/src/mc/mc_snapshot.c b/src/mc/mc_snapshot.c
index c733664f01..a7bd4dfea8 100644
--- a/src/mc/mc_snapshot.c
+++ b/src/mc/mc_snapshot.c
@@ -4,8 +4,11 @@
 /* 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. */
 
+#include <stdbool.h>
+
 #include "mc_private.h"
 #include "mc_mmu.h"
+#include "mc_page_store.h"
 
 mc_mem_region_t mc_get_snapshot_region(void* addr, mc_snapshot_t snapshot)
 {
@@ -22,45 +25,6 @@ mc_mem_region_t mc_get_snapshot_region(void* addr, mc_snapshot_t snapshot)
   return NULL;
 }
 
-void* mc_translate_address_region(uintptr_t addr, mc_mem_region_t region)
-{
-  xbt_assert(mc_region_contain(region, (void*) addr), "Trying to read out of the region boundary.");
-
-  if (!region) {
-    return (void *) addr;
-  }
-
-  // Flat snapshot:
-  else if (region->data) {
-    uintptr_t offset = addr - (uintptr_t) region->start_addr;
-    return (void *) ((uintptr_t) region->data + offset);
-  }
-
-  // Per-page snapshot:
-  else if (region->page_numbers) {
-    size_t pageno = mc_page_number(region->start_addr, (void*) addr);
-    size_t snapshot_pageno = region->page_numbers[pageno];
-    const void* snapshot_page = mc_page_store_get_page(mc_model_checker->pages, snapshot_pageno);
-    return (char*) snapshot_page + mc_page_offset((void*) addr);
-  }
-
-  else {
-    xbt_die("No data for this memory region");
-  }
-}
-
-void* mc_translate_address(uintptr_t addr, mc_snapshot_t snapshot)
-{
-
-  // If not in a process state/clone:
-  if (!snapshot) {
-    return (uintptr_t *) addr;
-  }
-
-  mc_mem_region_t region = mc_get_snapshot_region((void*) addr, snapshot);
-  return mc_translate_address_region(addr, region);
-}
-
 /** @brief Read memory from a snapshot region broken across fragmented pages
  *
  *  @param addr    Process (non-snapshot) address of the data
@@ -69,7 +33,7 @@ void* mc_translate_address(uintptr_t addr, mc_snapshot_t snapshot)
  *  @param size    Size of the data to read in bytes
  *  @return Pointer where the data is located (target buffer of original location)
  */
-static void* mc_snapshot_read_fragmented(void* addr, mc_mem_region_t region, void* target, size_t size)
+void* mc_snapshot_read_fragmented(void* addr, mc_mem_region_t region, void* target, size_t size)
 {
   void* end = (char*) addr + size - 1;
   size_t page_end = mc_page_number(NULL, end);
@@ -93,43 +57,6 @@ static void* mc_snapshot_read_fragmented(void* addr, mc_mem_region_t region, voi
   return target;
 }
 
-/** @brief Read memory from a snapshot region
- *
- *  @param addr    Process (non-snapshot) address of the data
- *  @param region  Snapshot memory region where the data is located
- *  @param target  Buffer to store the value
- *  @param size    Size of the data to read in bytes
- *  @return Pointer where the data is located (target buffer of original location)
- */
-void* mc_snapshot_read_region(void* addr, mc_mem_region_t region, void* target, size_t size)
-{
-  uintptr_t offset = (uintptr_t) addr - (uintptr_t) region->start_addr;
-
-  xbt_assert(addr >= region->start_addr && (char*) addr+size < (char*)region->start_addr+region->size,
-    "Trying to read out of the region boundary.");
-
-  // Linear memory region:
-  if (region->data) {
-    return (void*) ((uintptr_t) region->data + offset);
-  }
-
-  // Fragmented memory region:
-  else if (region->page_numbers) {
-    void* end = (char*) addr + size - 1;
-    if( mc_same_page(addr, end) ) {
-      // The memory is contained in a single page:
-      return mc_translate_address_region((uintptr_t) addr, region);
-    } else {
-      // The memory spans several pages:
-      return mc_snapshot_read_fragmented(addr, region, target, size);
-    }
-  }
-
-  else {
-    xbt_die("No data available for this region");
-  }
-}
-
 /** @brief Read memory from a snapshot
  *
  *  @param addr     Process (non-snapshot) address of the data
@@ -160,13 +87,23 @@ int mc_snapshot_region_memcp(
   void* addr1, mc_mem_region_t region1,
   void* addr2, mc_mem_region_t region2, size_t size)
 {
-  // TODO, optimize this, avoid alloca
-  void* buffer1 = mc_snapshot_read_region(addr1, region1, alloca(size), size);
-  void* buffer2 = mc_snapshot_read_region(addr2, region2, alloca(size), size);
+  // Using alloca() for large allocations may trigger stack overflow:
+  // use malloc if the buffer is too big.
+
+  bool stack_alloc = size < 64;
+  void* buffer = stack_alloc ? alloca(2*size) : malloc(2*size);
+  void* buffer1 = mc_snapshot_read_region(addr1, region1, buffer, size);
+  void* buffer2 = mc_snapshot_read_region(addr2, region2, (char*) buffer + size, size);
+  int res;
   if (buffer1 == buffer2) {
-    return 0;
+    res =  0;
+  } else {
+    res = memcmp(buffer1, buffer2, size);
+  }
+  if (!stack_alloc) {
+    free(buffer);
   }
-  return memcmp(buffer1, buffer2, size);
+  return res;
 }
 
 /** Compare memory between snapshots
@@ -181,11 +118,7 @@ int mc_snapshot_memcp(
   void* addr1, mc_snapshot_t snapshot1,
   void* addr2, mc_snapshot_t snapshot2, size_t size)
 {
-  // TODO, optimize this, avoid alloca
-  void* buffer1 = mc_snapshot_read(addr1, snapshot1, alloca(size), size);
-  void* buffer2 = mc_snapshot_read(addr2, snapshot2, alloca(size), size);
-  if (buffer1 == buffer2) {
-    return 0;
-  }
-  return memcmp(buffer1, buffer2, size);
+  mc_mem_region_t region1 = mc_get_snapshot_region(addr1, snapshot1);
+  mc_mem_region_t region2 = mc_get_snapshot_region(addr2, snapshot2);
+  return mc_snapshot_region_memcp(addr1, region1, addr2, region2, size);
 }