X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/41ac2593deb812baee12c58b6b7c4911a2da8cd7..15ab58c0b9a3d96ed52f5db885b72724a96af934:/src/mc/mc_snapshot.c

diff --git a/src/mc/mc_snapshot.c b/src/mc/mc_snapshot.c
index 998b85bbc9..7f3629145b 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)
 {
@@ -22,8 +25,39 @@ mc_mem_region_t mc_get_snapshot_region(void* addr, mc_snapshot_t snapshot)
   return NULL;
 }
 
+static inline __attribute__((always_inline))
 void* mc_translate_address_region(uintptr_t addr, mc_mem_region_t region)
 {
+    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);
+}
+
+/** \brief Translate a pointer from process address space to snapshot address space
+ *
+ *  The address space contains snapshot of the main/application memory:
+ *  this function finds the address in a given snaphot for a given
+ *  real/application address.
+ *
+ *  For read only memory regions and other regions which are not int the
+ *  snapshot, the address is not changed.
+ *
+ *  \param addr     Application address
+ *  \param snapshot The snapshot of interest (if NULL no translation is done)
+ *  \return         Translated address in the snapshot address space
+ * */
+static inline __attribute__((always_inline))
+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);
+
   xbt_assert(mc_region_contain(region, (void*) addr), "Trying to read out of the region boundary.");
 
   if (!region) {
@@ -38,10 +72,7 @@ void* mc_translate_address_region(uintptr_t addr, mc_mem_region_t region)
 
   // 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);
+    return mc_translate_address_region(addr, region);
   }
 
   else {
@@ -49,18 +80,6 @@ void* mc_translate_address_region(uintptr_t addr, mc_mem_region_t 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
@@ -148,26 +167,50 @@ void* mc_snapshot_read(void* addr, mc_snapshot_t snapshot, void* target, size_t
   }
 }
 
+/** Compare memory between snapshots (with known regions)
+ *
+ * @param addr1 Address in the first snapshot
+ * @param snapshot2 Region of the address in the first snapshot
+ * @param addr2 Address in the second snapshot
+ * @param snapshot2 Region of the address in the second snapshot
+ * @return same as memcmp
+ * */
 int mc_snapshot_region_memcp(
   void* addr1, mc_mem_region_t region1,
   void* addr2, mc_mem_region_t region2, size_t size)
 {
-  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
+ *
+ * @param addr1 Address in the first snapshot
+ * @param snapshot1 First snapshot
+ * @param addr2 Address in the second snapshot
+ * @param snapshot2 Second snapshot
+ * @return same as memcmp
+ * */
 int mc_snapshot_memcp(
   void* addr1, mc_snapshot_t snapshot1,
   void* addr2, mc_snapshot_t snapshot2, size_t size)
 {
-  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);
 }