-/* Copyright (c) 2014-2019. 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 "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 {
+namespace simgrid::mc {
/************************************* Take Snapshot ************************************/
/****************************************************************************************/
-void simgrid::mc::Snapshot::snapshot_regions(simgrid::mc::RemoteClient* process)
+void Snapshot::snapshot_regions(RemoteProcess* 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);
+ add_region(RegionType::Data, object_info.get(), object_info->start_rw, object_info->end_rw - object_info->start_rw);
- xbt_mheap_t heap = process->get_heap();
+ const s_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);
+ add_region(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());
}
* @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)
+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 true;
}
-static void fill_local_variables_values(mc_stack_frame_t stack_frame, simgrid::mc::Frame* scope,
+static void fill_local_variables_values(mc_stack_frame_t stack_frame, 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) {
-
+ 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;
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());
+ 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->get_remote_process());
- if (not location.in_memory())
- xbt_die("Cannot handle non-address variable");
+ xbt_assert(location.in_memory(), "Cannot handle non-address variable");
new_var.address = location.address();
-
} else
xbt_die("No address");
}
// Recursive processing of nested scopes:
- for (simgrid::mc::Frame& nested_scope : scope->scopes)
+ for (Frame& nested_scope : scope->scopes)
fill_local_variables_values(stack_frame, &nested_scope, result);
}
return variables;
}
-static std::vector<s_mc_stack_frame_t> unwind_stack_frames(simgrid::mc::UnwindContext* stack_context)
+static std::vector<s_mc_stack_frame_t> unwind_stack_frames(UnwindContext* stack_context)
{
- simgrid::mc::RemoteClient* process = &mc_model_checker->process();
+ const RemoteProcess* process = &mc_model_checker->get_remote_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) {
-
+ while (true) {
s_mc_stack_frame_t stack_frame;
stack_frame.unw_cursor = c;
// TODO, use real addresses in frame_t instead of fixing it here
- simgrid::mc::Frame* frame = process->find_function(remote(ip));
+ Frame* frame = process->find_function(remote(ip));
stack_frame.frame = frame;
if (frame) {
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(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 simgrid::mc::Snapshot::snapshot_stacks(simgrid::mc::RemoteClient* process)
+void Snapshot::snapshot_stacks(RemoteProcess* process)
{
for (auto const& stack : process->stack_areas()) {
s_mc_snapshot_stack_t st;
}
}
-static void snapshot_handle_ignore(simgrid::mc::Snapshot* snapshot)
+void Snapshot::handle_ignore()
{
- xbt_assert(snapshot->process());
+ xbt_assert(get_remote_process());
// Copy the memory:
- for (auto const& region : snapshot->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->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->process()->ignored_regions())
- snapshot->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(simgrid::mc::Snapshot* snapshot)
+
+void Snapshot::ignore_restore() const
{
- for (auto const& ignored_data : snapshot->ignored_data_)
- snapshot->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, RemoteClient* process)
- : AddressSpace(process), num_state_(num_state), heap_bytes_used_(0), enabled_processes_(), hash_(0)
+Snapshot::Snapshot(long num_state, RemoteProcess* process) : AddressSpace(process), num_state_(num_state)
{
- XBT_DEBUG("Taking snapshot %i", num_state);
+ XBT_DEBUG("Taking snapshot %ld", num_state);
- for (auto const& p : process->actors())
- enabled_processes_.insert(p.copy.get_buffer()->get_pid());
-
- snapshot_handle_ignore(this);
+ handle_ignore();
/* Save the std heap and the writable mapped pages of libsimgrid and binary */
snapshot_regions(process);
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);
+ 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)
{
- if (type == simgrid::mc::RegionType::Data)
+ if (type == RegionType::Data)
xbt_assert(object_info, "Missing object info for object.");
- else if (type == simgrid::mc::RegionType::Heap)
+ else if (type == RegionType::Heap)
xbt_assert(not object_info, "Unexpected object info for heap region.");
- simgrid::mc::Region* region = new Region(type, start_addr, size);
+ auto* 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)));
+ snapshot_regions_.push_back(std::unique_ptr<Region>(region));
}
-const void* Snapshot::read_bytes(void* buffer, std::size_t size, RemotePtr<void> address, ReadOptions options) 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());
+ const Region* region = this->get_region((void*)address.address());
if (region) {
- const void* res = MC_region_read(region, buffer, (void*)address.address(), size);
+ void* res = region->read(buffer, (void*)address.address(), size);
if (buffer == res || options & ReadOptions::lazy())
return res;
else {
return buffer;
}
} else
- return this->process()->read_bytes(buffer, size, address, options);
+ return this->get_remote_process()->read_bytes(buffer, size, address, options);
}
-/** @brief Find the snapshoted region from a pointer
+/** @brief Find the snapshotted region from a pointer
*
* @param addr Pointer
* */
return nullptr;
}
-/** @brief Find the snapshoted region from a pointer, with a hinted_region */
+/** @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 get_region(addr);
}
-void Snapshot::restore(RemoteClient* process)
+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<simgrid::mc::Region> const& region : snapshot_regions_) {
- if (region) // privatized variables are not snapshoted
+ for (std::unique_ptr<Region> const& region : snapshot_regions_) {
+ if (region) // privatized variables are not snapshotted
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
