Integrate the (WIP) hashing logic in the Snapshot object

[simgrid.git] / src / mc / sosp / Snapshot.cpp

diff --git a/src/mc/sosp/Snapshot.cpp b/src/mc/sosp/Snapshot.cpp
index b195356..b36d8cd 100644 (file)
--- a/src/mc/sosp/Snapshot.cpp
+++ b/src/mc/sosp/Snapshot.cpp
@@ -1,17 +1,15 @@
-/* Copyright (c) 2014-2021. The SimGrid Team. All rights reserved.          */
+/* Copyright (c) 2014-2022. 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. */
 
 #include "src/mc/sosp/Snapshot.hpp"
 #include "src/mc/mc_config.hpp"
-#include "src/mc/mc_hash.hpp"
 
 #include <cstddef> /* std::size_t */
 
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_snapshot, mc, "Taking and restoring snapshots");
-namespace simgrid {
-namespace mc {
+namespace simgrid::mc {
 /************************************* Take Snapshot ************************************/
 /****************************************************************************************/
 
@@ -58,6 +56,12 @@ static void fill_local_variables_values(mc_stack_frame_t stack_frame, Frame* sco
     if (not valid_variable(&current_variable, scope, (void*)stack_frame->ip))
       continue;
 
+    if (not current_variable.type) {
+      XBT_VERB("Ignore local variable without type: '%s' [%s]", current_variable.name.c_str(),
+               stack_frame->frame->name.c_str());
+      continue;
+    }
+
     s_local_variable_t new_var;
     new_var.subprogram = stack_frame->frame;
     new_var.ip         = stack_frame->ip;
@@ -168,40 +172,36 @@ void Snapshot::snapshot_stacks(RemoteProcess* process)
   }
 }
 
-static void snapshot_handle_ignore(Snapshot* snapshot)
+void Snapshot::handle_ignore()
 {
-  xbt_assert(snapshot->get_remote_process());
+  xbt_assert(get_remote_process());
 
   // Copy the memory:
-  for (auto const& region : snapshot->get_remote_process()->ignored_regions()) {
+  for (auto const& region : get_remote_process()->ignored_regions()) {
     s_mc_snapshot_ignored_data_t ignored_data;
     ignored_data.start = (void*)region.addr;
     ignored_data.data.resize(region.size);
     // TODO, we should do this once per privatization segment:
-    snapshot->get_remote_process()->read_bytes(ignored_data.data.data(), region.size, remote(region.addr));
-    snapshot->ignored_data_.push_back(std::move(ignored_data));
+    get_remote_process()->read_bytes(ignored_data.data.data(), region.size, remote(region.addr));
+    ignored_data_.push_back(std::move(ignored_data));
   }
 
   // Zero the memory:
-  for (auto const& region : snapshot->get_remote_process()->ignored_regions())
-    snapshot->get_remote_process()->clear_bytes(remote(region.addr), region.size);
+  for (auto const& region : get_remote_process()->ignored_regions())
+    get_remote_process()->clear_bytes(remote(region.addr), region.size);
 }
 
-static void snapshot_ignore_restore(const simgrid::mc::Snapshot* snapshot)
+void Snapshot::ignore_restore() const
 {
-  for (auto const& ignored_data : snapshot->ignored_data_)
-    snapshot->get_remote_process()->write_bytes(ignored_data.data.data(), ignored_data.data.size(),
-                                                remote(ignored_data.start));
+  for (auto const& ignored_data : ignored_data_)
+    get_remote_process()->write_bytes(ignored_data.data.data(), ignored_data.data.size(), remote(ignored_data.start));
 }
 
-Snapshot::Snapshot(int num_state, RemoteProcess* process) : AddressSpace(process), num_state_(num_state)
+Snapshot::Snapshot(long num_state, RemoteProcess* process) : AddressSpace(process), num_state_(num_state)
 {
-  XBT_DEBUG("Taking snapshot %i", num_state);
-
-  for (auto const& p : process->actors())
-    enabled_processes_.insert(p.copy.get_buffer()->get_pid());
+  XBT_DEBUG("Taking snapshot %ld", num_state);
 
-  snapshot_handle_ignore(this);
+  handle_ignore();
 
   /* Save the std heap and the writable mapped pages of libsimgrid and binary */
   snapshot_regions(process);
@@ -210,10 +210,10 @@ Snapshot::Snapshot(int num_state, RemoteProcess* process) : AddressSpace(process
 
   if (_sg_mc_max_visited_states > 0 || not _sg_mc_property_file.get().empty()) {
     snapshot_stacks(process);
-    hash_ = simgrid::mc::hash(*this);
+    hash_ = this->do_hash();
   }
 
-  snapshot_ignore_restore(this);
+  ignore_restore();
 }
 
 void Snapshot::add_region(RegionType type, ObjectInformation* object_info, void* start_addr, std::size_t size)
@@ -271,7 +271,7 @@ Region* Snapshot::get_region(const void* addr, Region* hinted_region) const
 
 void Snapshot::restore(RemoteProcess* process) const
 {
-  XBT_DEBUG("Restore snapshot %i", num_state_);
+  XBT_DEBUG("Restore snapshot %ld", num_state_);
 
   // Restore regions
   for (std::unique_ptr<Region> const& region : snapshot_regions_) {
@@ -279,9 +279,30 @@ void Snapshot::restore(RemoteProcess* process) const
       region.get()->restore();
   }
 
-  snapshot_ignore_restore(this);
+  ignore_restore();
   process->clear_cache();
 }
 
-} // namespace mc
-} // namespace simgrid
+/* ----------- Hashing logic -------------- */
+class djb_hash {
+  hash_type state_ = 5381LL;
+
+public:
+  template <class T> void update(T& x) { state_ = (state_ << 5) + state_ + x; }
+  hash_type value() const { return state_; }
+};
+hash_type Snapshot::do_hash() const
+{
+  XBT_DEBUG("START hash %ld", num_state_);
+  djb_hash hash;
+  // TODO:
+  // * nb_processes
+  // * heap_bytes_used
+  // * root variables
+  // * basic stack frame information
+  // * stack frame local variables
+  XBT_DEBUG("END hash %ld", num_state_);
+  return hash.value();
+}
+
+} // namespace simgrid::mc