[mc] Add some documentation

[simgrid.git] / src / mc / mc_snapshot.c

diff --git a/src/mc/mc_snapshot.c b/src/mc/mc_snapshot.c
index 38820c9..c733664 100644 (file)
--- a/src/mc/mc_snapshot.c
+++ b/src/mc/mc_snapshot.c
@@ -24,6 +24,8 @@ mc_mem_region_t mc_get_snapshot_region(void* addr, mc_snapshot_t snapshot)
 
 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;
   }
@@ -71,20 +73,22 @@ static void* mc_snapshot_read_fragmented(void* addr, mc_mem_region_t region, voi
 {
   void* end = (char*) addr + size - 1;
   size_t page_end = mc_page_number(NULL, end);
+  void* dest = target;
 
   // Read each page:
   while (mc_page_number(NULL, addr) != page_end) {
     void* snapshot_addr = mc_translate_address_region((uintptr_t) addr, region);
     void* next_page = mc_page_from_number(NULL, mc_page_number(NULL, addr) + 1);
     size_t readable = (char*) next_page - (char*) addr;
-    memcpy(target, snapshot_addr, readable);
-    target = (char*) target + readable;
+    memcpy(dest, snapshot_addr, readable);
+    addr = (char*) addr + readable;
+    dest = (char*) dest + readable;
     size -= readable;
   }
 
   // Read the end:
   void* snapshot_addr = mc_translate_address_region((uintptr_t)addr, region);
-  memcpy(target, snapshot_addr, size);
+  memcpy(dest, snapshot_addr, size);
 
   return target;
 }
@@ -101,9 +105,8 @@ void* mc_snapshot_read_region(void* addr, mc_mem_region_t region, void* target,
 {
   uintptr_t offset = (uintptr_t) addr - (uintptr_t) region->start_addr;
 
-  if (addr < region->start_addr || (char*) addr+size >= (char*)region->start_addr+region->size) {
-    xbt_die("Trying to read out of the region boundary.");
-  }
+  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) {
@@ -145,10 +148,40 @@ 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)
+{
+  // 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);
+  if (buffer1 == buffer2) {
+    return 0;
+  }
+  return memcmp(buffer1, buffer2, size);
+}
+
+/** 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)
 {
+  // 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) {