+++ /dev/null
-/* Copyright (c) 2014-2023. 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 <cstddef> /* std::size_t */
-
-XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_snapshot, mc, "Taking and restoring snapshots");
-namespace simgrid::mc {
-/************************************* Take Snapshot ************************************/
-/****************************************************************************************/
-
-void Snapshot::snapshot_regions(RemoteProcessMemory& memory)
-{
- snapshot_regions_.clear();
-
- for (auto const& object_info : memory.object_infos)
- add_region(RegionType::Data, memory, object_info.get(), object_info->start_rw,
- object_info->end_rw - object_info->start_rw);
-
- const s_xbt_mheap_t* heap = memory.get_heap();
- void* start_heap = heap->base;
- void* end_heap = heap->breakval;
-
- add_region(RegionType::Heap, memory, nullptr, start_heap, (char*)end_heap - (char*)start_heap);
- heap_bytes_used_ = mmalloc_get_bytes_used_remote(heap->heaplimit, memory.get_malloc_info());
-}
-
-/** @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 scope Scope description
- * @param ip Instruction pointer
- * @return true if the variable is valid
- * */
-static bool valid_variable(const simgrid::mc::Variable* var, simgrid::mc::Frame* scope, const void* ip)
-{
- // The variable is not yet valid:
- if (scope->range.begin() + var->start_scope > (std::uint64_t)ip)
- return false;
- else
- return true;
-}
-
-static void fill_local_variables_values(mc_stack_frame_t stack_frame, Frame* scope,
- std::vector<s_local_variable_t>& result, AddressSpace* memory)
-{
- if (not scope || not scope->range.contain(stack_frame->ip))
- return;
-
- for (const Variable& current_variable : scope->variables) {
- if (not valid_variable(¤t_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;
- new_var.name = current_variable.name;
- new_var.type = current_variable.type;
- new_var.address = nullptr;
-
- if (current_variable.address != nullptr)
- new_var.address = current_variable.address;
- else if (not current_variable.location_list.empty()) {
- dwarf::Location location =
- simgrid::dwarf::resolve(current_variable.location_list, current_variable.object_info,
- &(stack_frame->unw_cursor), (void*)stack_frame->frame_base, memory);
-
- xbt_assert(location.in_memory(), "Cannot handle non-address variable");
- new_var.address = location.address();
- } else
- xbt_die("No address");
-
- result.push_back(std::move(new_var));
- }
-
- // Recursive processing of nested scopes:
- for (Frame& nested_scope : scope->scopes)
- fill_local_variables_values(stack_frame, &nested_scope, result, memory);
-}
-
-static std::vector<s_local_variable_t> get_local_variables_values(std::vector<s_mc_stack_frame_t>& stack_frames,
- AddressSpace* memory)
-{
- std::vector<s_local_variable_t> variables;
- for (s_mc_stack_frame_t& stack_frame : stack_frames)
- fill_local_variables_values(&stack_frame, stack_frame.frame, variables, memory);
- return variables;
-}
-
-static std::vector<s_mc_stack_frame_t> unwind_stack_frames(UnwindContext* stack_context,
- const RemoteProcessMemory* process_memory)
-{
- std::vector<s_mc_stack_frame_t> result;
-
- unw_cursor_t c = stack_context->cursor();
-
- // TODO, check condition check (unw_init_local==0 means end of frame)
-
- while (true) {
- s_mc_stack_frame_t stack_frame;
-
- stack_frame.unw_cursor = c;
-
- unw_word_t ip;
- unw_word_t 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
-
- Frame* frame = process_memory->find_function(remote(ip));
- stack_frame.frame = frame;
-
- if (frame) {
- stack_frame.frame_name = frame->name;
- stack_frame.frame_base = (unw_word_t)frame->frame_base(c);
- } else {
- stack_frame.frame_base = 0;
- stack_frame.frame_name = "";
- }
-
- result.push_back(std::move(stack_frame));
-
- /* Stop before context switch with maestro */
- if (frame != nullptr && frame->name == "smx_ctx_wrapper")
- break;
-
- int ret = unw_step(&c);
- xbt_assert(ret >= 0, "Error while unwinding stack");
- xbt_assert(ret != 0, "Unexpected end of stack.");
- }
-
- xbt_assert(not result.empty(), "unw_init_local failed");
-
- return result;
-}
-
-void Snapshot::snapshot_stacks(RemoteProcessMemory& process_memory)
-{
- for (auto const& stack : process_memory.stack_areas()) {
- s_mc_snapshot_stack_t st;
-
- // Read the context from remote process memory:
- unw_context_t context;
- process_memory.read_bytes(&context, sizeof(context), remote(stack.context));
-
- st.context.initialize(process_memory, &context);
-
- st.stack_frames = unwind_stack_frames(&st.context, &process_memory);
- st.local_variables = get_local_variables_values(st.stack_frames, &process_memory);
-
- unw_word_t sp = st.stack_frames[0].sp;
-
- stacks_.push_back(std::move(st));
-
- size_t stack_size = (char*)stack.address + stack.size - (char*)sp;
- stack_sizes_.push_back(stack_size);
- }
-}
-
-void Snapshot::handle_ignore()
-{
- xbt_assert(get_remote_process_memory());
-
- // Copy the memory:
- for (auto const& region : get_remote_process_memory()->ignored_regions()) {
- s_mc_snapshot_ignored_data_t ignored_data;
- ignored_data.start = (void*)region.addr;
- ignored_data.data.resize(region.size);
- get_remote_process_memory()->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 : get_remote_process_memory()->ignored_regions())
- get_remote_process_memory()->clear_bytes(remote(region.addr), region.size);
-}
-
-void Snapshot::ignore_restore() const
-{
- for (auto const& ignored_data : ignored_data_)
- get_remote_process_memory()->write_bytes(ignored_data.data.data(), ignored_data.data.size(),
- remote(ignored_data.start));
-}
-
-Snapshot::Snapshot(long num_state, PageStore& store, RemoteProcessMemory& memory)
- : AddressSpace(&memory), page_store_(store), num_state_(num_state)
-{
- XBT_DEBUG("Taking snapshot %ld", num_state);
-
- handle_ignore();
-
- /* Save the std heap and the writable mapped pages of libsimgrid and binary */
- snapshot_regions(memory);
-
- to_ignore_ = memory.ignored_heap();
-
- if (_sg_mc_max_visited_states > 0 || not _sg_mc_property_file.get().empty()) {
- snapshot_stacks(memory);
- hash_ = this->do_hash();
- }
-
- ignore_restore();
-}
-
-void Snapshot::add_region(RegionType type, const RemoteProcessMemory& memory, ObjectInformation* object_info,
- void* start_addr, std::size_t size)
-{
- if (type == RegionType::Data)
- xbt_assert(object_info, "Missing object info for object.");
- else if (type == RegionType::Heap)
- xbt_assert(not object_info, "Unexpected object info for heap region.");
-
- auto region = std::make_unique<Region>(page_store_, memory, type, start_addr, size);
- region->object_info(object_info);
- snapshot_regions_.push_back(std::move(region));
-}
-
-void* Snapshot::read_bytes(void* buffer, std::size_t size, RemotePtr<void> address, ReadOptions options) const
-{
- const Region* region = this->get_region((void*)address.address());
- if (region) {
- void* res = region->read(buffer, (void*)address.address(), size);
- if (buffer == res || options & ReadOptions::lazy())
- return res;
- else {
- memcpy(buffer, res, size);
- return buffer;
- }
- } else
- return this->get_remote_process_memory()->read_bytes(buffer, size, address, options);
-}
-/** @brief Find the snapshotted region from a pointer
- *
- * @param addr Pointer
- * */
-Region* Snapshot::get_region(const void* addr) const
-{
- size_t n = snapshot_regions_.size();
- for (size_t i = 0; i != n; ++i) {
- Region* region = snapshot_regions_[i].get();
- if (not(region && region->contain(simgrid::mc::remote(addr))))
- continue;
-
- return region;
- }
-
- return nullptr;
-}
-
-/** @brief Find the snapshotted region from a pointer, with a hinted_region */
-Region* Snapshot::get_region(const void* addr, Region* hinted_region) const
-{
- if (hinted_region->contain(simgrid::mc::remote(addr)))
- return hinted_region;
- else
- return get_region(addr);
-}
-
-void Snapshot::restore(RemoteProcessMemory& memory) const
-{
- XBT_DEBUG("Restore snapshot %ld", num_state_);
-
- // Restore regions
- for (std::unique_ptr<Region> const& region : snapshot_regions_) {
- region->restore(memory);
- }
-
- ignore_restore();
- memory.clear_cache();
-}
-
-/* ----------- 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
