+++ /dev/null
-/* Copyright (c) 2014-2019. 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 "src/mc/mc_smx.hpp"
-
-#include <cstddef> /* std::size_t */
-
-XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_snapshot, mc, "Taking and restoring snapshots");
-
-/** @brief Read memory from a snapshot region broken across fragmented pages
- *
- * @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)
- */
-const void* MC_region_read_fragmented(simgrid::mc::Region* region, void* target, const void* addr, size_t size)
-{
- // Last byte of the memory area:
- void* end = (char*)addr + size - 1;
-
- // TODO, we assume the chunks are aligned to natural chunk boundaries.
- // We should remove this assumption.
-
- // Page of the last byte of the memory area:
- size_t page_end = simgrid::mc::mmu::split((std::uintptr_t)end).first;
-
- void* dest = target;
-
- if (dest == nullptr)
- xbt_die("Missing destination buffer for fragmented memory access");
-
- // Read each page:
- while (simgrid::mc::mmu::split((std::uintptr_t)addr).first != page_end) {
- void* snapshot_addr = mc_translate_address_region((uintptr_t)addr, region);
- void* next_page = (void*)simgrid::mc::mmu::join(simgrid::mc::mmu::split((std::uintptr_t)addr).first + 1, 0);
- size_t readable = (char*)next_page - (char*)addr;
- 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(dest, snapshot_addr, size);
-
- return target;
-}
-
-/** Compare memory between snapshots (with known regions)
- *
- * @param addr1 Address in the first snapshot
- * @param region1 Region of the address in the first snapshot
- * @param addr2 Address in the second snapshot
- * @param region2 Region of the address in the second snapshot
- * @return same semantic as memcmp
- */
-int MC_snapshot_region_memcmp(const void* addr1, simgrid::mc::Region* region1, const void* addr2,
- simgrid::mc::Region* region2, size_t size)
-{
- // Using alloca() for large allocations may trigger stack overflow:
- // use malloc if the buffer is too big.
- bool stack_alloc = size < 64;
- void* buffer1a = stack_alloc ? alloca(size) : ::operator new(size);
- void* buffer2a = stack_alloc ? alloca(size) : ::operator new(size);
- const void* buffer1 = MC_region_read(region1, buffer1a, addr1, size);
- const void* buffer2 = MC_region_read(region2, buffer2a, addr2, size);
- int res;
- if (buffer1 == buffer2)
- res = 0;
- else
- res = memcmp(buffer1, buffer2, size);
- if (not stack_alloc) {
- ::operator delete(buffer1a);
- ::operator delete(buffer2a);
- }
- return res;
-}
-
-namespace simgrid {
-namespace mc {
-/************************************* Take Snapshot ************************************/
-/****************************************************************************************/
-
-void simgrid::mc::Snapshot::snapshot_regions(simgrid::mc::RemoteClient* process)
-{
- snapshot_regions_.clear();
-
- for (auto const& object_info : process->object_infos)
- add_region(simgrid::mc::RegionType::Data, object_info.get(), object_info->start_rw,
- object_info->end_rw - object_info->start_rw);
-
- xbt_mheap_t heap = process->get_heap();
- void* start_heap = heap->base;
- void* end_heap = heap->breakval;
-
- add_region(simgrid::mc::RegionType::Heap, nullptr, start_heap, (char*)end_heap - (char*)start_heap);
- heap_bytes_used_ = mmalloc_get_bytes_used_remote(heap->heaplimit, process->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(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, simgrid::mc::Frame* scope,
- std::vector<s_local_variable_t>& result)
-{
- if (not scope || not scope->range.contain(stack_frame->ip))
- return;
-
- for (simgrid::mc::Variable& current_variable : scope->variables) {
-
- if (not valid_variable(¤t_variable, scope, (void*)stack_frame->ip))
- 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()) {
- simgrid::dwarf::Location location = simgrid::dwarf::resolve(
- current_variable.location_list, current_variable.object_info, &(stack_frame->unw_cursor),
- (void*)stack_frame->frame_base, &mc_model_checker->process());
-
- if (not location.in_memory())
- xbt_die("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 (simgrid::mc::Frame& nested_scope : scope->scopes)
- fill_local_variables_values(stack_frame, &nested_scope, result);
-}
-
-static std::vector<s_local_variable_t> get_local_variables_values(std::vector<s_mc_stack_frame_t>& stack_frames)
-{
- 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);
- return variables;
-}
-
-static std::vector<s_mc_stack_frame_t> unwind_stack_frames(simgrid::mc::UnwindContext* stack_context)
-{
- simgrid::mc::RemoteClient* process = &mc_model_checker->process();
- 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 (1) {
-
- 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
-
- simgrid::mc::Frame* frame = process->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 = std::string();
- }
-
- 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);
- if (ret == 0)
- xbt_die("Unexpected end of stack.");
- else if (ret < 0)
- xbt_die("Error while unwinding stack");
- }
-
- xbt_assert(not result.empty(), "unw_init_local failed");
-
- return result;
-}
-
-void simgrid::mc::Snapshot::snapshot_stacks(simgrid::mc::RemoteClient* process)
-{
- for (auto const& stack : process->stack_areas()) {
- s_mc_snapshot_stack_t st;
-
- // Read the context from remote process:
- unw_context_t context;
- process->read_bytes(&context, sizeof(context), remote(stack.context));
-
- st.context.initialize(process, &context);
-
- st.stack_frames = unwind_stack_frames(&st.context);
- st.local_variables = get_local_variables_values(st.stack_frames);
-
- 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);
- }
-}
-
-static void snapshot_handle_ignore(simgrid::mc::Snapshot* snapshot)
-{
- xbt_assert(snapshot->process());
-
- // Copy the memory:
- for (auto const& region : snapshot->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->process()->read_bytes(ignored_data.data.data(), region.size, remote(region.addr));
- snapshot->ignored_data_.push_back(std::move(ignored_data));
- }
-
- // Zero the memory:
- for (auto const& region : snapshot->process()->ignored_regions())
- snapshot->process()->clear_bytes(remote(region.addr), region.size);
-}
-static void snapshot_ignore_restore(simgrid::mc::Snapshot* snapshot)
-{
- for (auto const& ignored_data : snapshot->ignored_data_)
- snapshot->process()->write_bytes(ignored_data.data.data(), ignored_data.data.size(), remote(ignored_data.start));
-}
-
-Snapshot::Snapshot(int num_state, RemoteClient* process)
- : AddressSpace(process), num_state_(num_state), heap_bytes_used_(0), enabled_processes_(), hash_(0)
-{
- XBT_DEBUG("Taking snapshot %i", num_state);
-
- for (auto const& p : process->actors())
- enabled_processes_.insert(p.copy.get_buffer()->get_pid());
-
- snapshot_handle_ignore(this);
-
- /* Save the std heap and the writable mapped pages of libsimgrid and binary */
- snapshot_regions(process);
-
- to_ignore_ = process->ignored_heap();
-
- if (_sg_mc_max_visited_states > 0 || not _sg_mc_property_file.get().empty()) {
- snapshot_stacks(process);
- if (_sg_mc_hash)
- hash_ = simgrid::mc::hash(*this);
- }
-
- snapshot_ignore_restore(this);
-}
-
-void Snapshot::add_region(RegionType type, ObjectInformation* object_info, void* start_addr, std::size_t size)
-{
- if (type == simgrid::mc::RegionType::Data)
- xbt_assert(object_info, "Missing object info for object.");
- else if (type == simgrid::mc::RegionType::Heap)
- xbt_assert(not object_info, "Unexpected object info for heap region.");
-
- simgrid::mc::Region* region = new Region(type, start_addr, size);
- region->object_info(object_info);
- snapshot_regions_.push_back(std::unique_ptr<simgrid::mc::Region>(std::move(region)));
-}
-
-const void* Snapshot::read_bytes(void* buffer, std::size_t size, RemotePtr<void> address, ReadOptions options) const
-{
- Region* region = this->get_region((void*)address.address());
- if (region) {
- const void* res = MC_region_read(region, buffer, (void*)address.address(), size);
- if (buffer == res || options & ReadOptions::lazy())
- return res;
- else {
- memcpy(buffer, res, size);
- return buffer;
- }
- } else
- return this->process()->read_bytes(buffer, size, address, options);
-}
-/** @brief Find the snapshoted 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 snapshoted 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(RemoteClient* process)
-{
- XBT_DEBUG("Restore snapshot %i", num_state_);
-
- // Restore regions
- for (std::unique_ptr<simgrid::mc::Region> const& region : snapshot_regions_) {
- if (region) // privatized variables are not snapshoted
- region.get()->restore();
- }
-
- snapshot_ignore_restore(this);
- process->clear_cache();
-}
-
-} // namespace mc
-} // namespace simgrid
