crashpad/minidump/minidump_thread_writer.cc
Scott Graham 9b6c69cbb5 Coalesce memory ranges
Follows https://chromium-review.googlesource.com/c/374019/.

Causes MinidumpMemoryListWriter to merge all overlapping ranges before
writing the MINIDUMP_MEMORY_LIST. This is:

1) Necessary for the Google internal crash processor, which in some
   cases attempts to read the raw memory (displaying ASAN red zones),
   and aborts if there are any overlapping ranges in the minidump on
   load;

2) Necessary for new-ish versions of windbg (see bug 216 below). It is
   believed that this is a change in behavior in the tool that made
   dumps with overlapping ranges unreadable;

3) More efficient. The .dmp for crashy_program goes from 306K to 140K
   with this enabled. In Chrome minidumps where
   set_gather_indirectly_referenced_memory() is used (in practice this
   means Chrome Windows Beta, Dev, and Canary), the savings are expected
   to be substantial.

Bug: crashpad:61, chromium:638370, crashpad:216

Change-Id: I969e1a52da555ceba59a727d933bfeef6787c7a5
Reviewed-on: https://chromium-review.googlesource.com/374539
Commit-Queue: Scott Graham <scottmg@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
2018-02-02 00:04:20 +00:00

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// Copyright 2014 The Crashpad Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "minidump/minidump_thread_writer.h"
#include <utility>
#include "base/logging.h"
#include "minidump/minidump_context_writer.h"
#include "minidump/minidump_memory_writer.h"
#include "snapshot/memory_snapshot.h"
#include "snapshot/thread_snapshot.h"
#include "util/file/file_writer.h"
#include "util/numeric/safe_assignment.h"
namespace crashpad {
MinidumpThreadWriter::MinidumpThreadWriter()
: MinidumpWritable(), thread_(), stack_(nullptr), context_(nullptr) {
}
MinidumpThreadWriter::~MinidumpThreadWriter() {
}
void MinidumpThreadWriter::InitializeFromSnapshot(
const ThreadSnapshot* thread_snapshot,
const MinidumpThreadIDMap* thread_id_map) {
DCHECK_EQ(state(), kStateMutable);
DCHECK(!stack_);
DCHECK(!context_);
auto thread_id_it = thread_id_map->find(thread_snapshot->ThreadID());
DCHECK(thread_id_it != thread_id_map->end());
SetThreadID(thread_id_it->second);
SetSuspendCount(thread_snapshot->SuspendCount());
SetPriority(thread_snapshot->Priority());
SetTEB(thread_snapshot->ThreadSpecificDataAddress());
const MemorySnapshot* stack_snapshot = thread_snapshot->Stack();
if (stack_snapshot && stack_snapshot->Size() > 0) {
std::unique_ptr<SnapshotMinidumpMemoryWriter> stack(
new SnapshotMinidumpMemoryWriter(stack_snapshot));
SetStack(std::move(stack));
}
std::unique_ptr<MinidumpContextWriter> context =
MinidumpContextWriter::CreateFromSnapshot(thread_snapshot->Context());
SetContext(std::move(context));
}
const MINIDUMP_THREAD* MinidumpThreadWriter::MinidumpThread() const {
DCHECK_EQ(state(), kStateWritable);
return &thread_;
}
void MinidumpThreadWriter::SetStack(
std::unique_ptr<SnapshotMinidumpMemoryWriter> stack) {
DCHECK_EQ(state(), kStateMutable);
stack_ = std::move(stack);
}
void MinidumpThreadWriter::SetContext(
std::unique_ptr<MinidumpContextWriter> context) {
DCHECK_EQ(state(), kStateMutable);
context_ = std::move(context);
}
bool MinidumpThreadWriter::Freeze() {
DCHECK_EQ(state(), kStateMutable);
CHECK(context_);
if (!MinidumpWritable::Freeze()) {
return false;
}
if (stack_) {
stack_->RegisterMemoryDescriptor(&thread_.Stack);
}
context_->RegisterLocationDescriptor(&thread_.ThreadContext);
return true;
}
size_t MinidumpThreadWriter::SizeOfObject() {
DCHECK_GE(state(), kStateFrozen);
// This object doesnt directly write anything itself. Its MINIDUMP_THREAD is
// written by its parent as part of a MINIDUMP_THREAD_LIST, and its children
// are responsible for writing themselves.
return 0;
}
std::vector<internal::MinidumpWritable*> MinidumpThreadWriter::Children() {
DCHECK_GE(state(), kStateFrozen);
DCHECK(context_);
std::vector<MinidumpWritable*> children;
if (stack_) {
children.push_back(stack_.get());
}
children.push_back(context_.get());
return children;
}
bool MinidumpThreadWriter::WriteObject(FileWriterInterface* file_writer) {
DCHECK_EQ(state(), kStateWritable);
// This object doesnt directly write anything itself. Its MINIDUMP_THREAD is
// written by its parent as part of a MINIDUMP_THREAD_LIST, and its children
// are responsible for writing themselves.
return true;
}
MinidumpThreadListWriter::MinidumpThreadListWriter()
: MinidumpStreamWriter(),
threads_(),
memory_list_writer_(nullptr),
thread_list_base_() {
}
MinidumpThreadListWriter::~MinidumpThreadListWriter() {
}
void MinidumpThreadListWriter::InitializeFromSnapshot(
const std::vector<const ThreadSnapshot*>& thread_snapshots,
MinidumpThreadIDMap* thread_id_map) {
DCHECK_EQ(state(), kStateMutable);
DCHECK(threads_.empty());
BuildMinidumpThreadIDMap(thread_snapshots, thread_id_map);
for (const ThreadSnapshot* thread_snapshot : thread_snapshots) {
auto thread = std::make_unique<MinidumpThreadWriter>();
thread->InitializeFromSnapshot(thread_snapshot, thread_id_map);
AddThread(std::move(thread));
}
// Do this in a separate loop to keep the thread stacks earlier in the dump,
// and together.
for (const ThreadSnapshot* thread_snapshot : thread_snapshots)
memory_list_writer_->AddFromSnapshot(thread_snapshot->ExtraMemory());
}
void MinidumpThreadListWriter::SetMemoryListWriter(
MinidumpMemoryListWriter* memory_list_writer) {
DCHECK_EQ(state(), kStateMutable);
DCHECK(threads_.empty());
memory_list_writer_ = memory_list_writer;
}
void MinidumpThreadListWriter::AddThread(
std::unique_ptr<MinidumpThreadWriter> thread) {
DCHECK_EQ(state(), kStateMutable);
if (memory_list_writer_) {
SnapshotMinidumpMemoryWriter* stack = thread->Stack();
if (stack) {
memory_list_writer_->AddNonOwnedMemory(stack);
}
}
threads_.push_back(std::move(thread));
}
bool MinidumpThreadListWriter::Freeze() {
DCHECK_EQ(state(), kStateMutable);
if (!MinidumpStreamWriter::Freeze()) {
return false;
}
size_t thread_count = threads_.size();
if (!AssignIfInRange(&thread_list_base_.NumberOfThreads, thread_count)) {
LOG(ERROR) << "thread_count " << thread_count << " out of range";
return false;
}
return true;
}
size_t MinidumpThreadListWriter::SizeOfObject() {
DCHECK_GE(state(), kStateFrozen);
return sizeof(thread_list_base_) + threads_.size() * sizeof(MINIDUMP_THREAD);
}
std::vector<internal::MinidumpWritable*> MinidumpThreadListWriter::Children() {
DCHECK_GE(state(), kStateFrozen);
std::vector<MinidumpWritable*> children;
for (const auto& thread : threads_) {
children.push_back(thread.get());
}
return children;
}
bool MinidumpThreadListWriter::WriteObject(FileWriterInterface* file_writer) {
DCHECK_EQ(state(), kStateWritable);
WritableIoVec iov;
iov.iov_base = &thread_list_base_;
iov.iov_len = sizeof(thread_list_base_);
std::vector<WritableIoVec> iovecs(1, iov);
for (const auto& thread : threads_) {
iov.iov_base = thread->MinidumpThread();
iov.iov_len = sizeof(MINIDUMP_THREAD);
iovecs.push_back(iov);
}
return file_writer->WriteIoVec(&iovecs);
}
MinidumpStreamType MinidumpThreadListWriter::StreamType() const {
return kMinidumpStreamTypeThreadList;
}
} // namespace crashpad