Add a basic compiler dispatcher

src/compiler-dispatcher/compiler-dispatcher.cc

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/compiler-dispatcher/compiler-dispatcher.h"
+
+#include "src/compiler-dispatcher/compiler-dispatcher-job.h"
+#include "src/compiler-dispatcher/compiler-dispatcher-tracer.h"
+#include "src/objects-inl.h"
+
+namespace v8 {
+namespace internal {
+
+namespace {
+
+bool DoNextStepOnMainThread(CompilerDispatcherJob* job) {
+  switch (job->status()) {
+    case CompileJobStatus::kInitial:
+      job->PrepareToParseOnMainThread();
+      break;
+
+    case CompileJobStatus::kReadyToParse:
+      job->Parse();
+      break;
+
+    case CompileJobStatus::kParsed:
+      job->FinalizeParsingOnMainThread();
+      break;
+
+    case CompileJobStatus::kReadyToAnalyse:
+      job->PrepareToCompileOnMainThread();
+      break;
+
+    case CompileJobStatus::kReadyToCompile:
+      job->Compile();
+      break;
+
+    case CompileJobStatus::kCompiled:
+      job->FinalizeCompilingOnMainThread();
+      break;
+
+    case CompileJobStatus::kFailed:
+    case CompileJobStatus::kDone:
+      break;
+  }
+
+  return job->status() != CompileJobStatus::kFailed;
+}
+
+bool IsDone(CompilerDispatcherJob* job) {
+  return job->status() == CompileJobStatus::kDone ||
+         job->status() == CompileJobStatus::kFailed;
+}
+
+}  // namespace
+
+CompilerDispatcher::CompilerDispatcher(Isolate* isolate, size_t max_stack_size)
+    : isolate_(isolate),
+      max_stack_size_(max_stack_size),
+      tracer_(new CompilerDispatcherTracer(isolate_)) {}
+
+CompilerDispatcher::~CompilerDispatcher() {}
+
+bool CompilerDispatcher::Enqueue(Handle<SharedFunctionInfo> function) {

[marja, 2016/12/12 12:25:01]

Now the return value is not meaningful any more.

[jochen (gone - plz use gerrit), 2016/12/12 12:34:37]

I added a meaningful "return false" code path

+  DCHECK(function->script()->IsScript());
+  if (IsEnqueued(function)) return true;
+  std::unique_ptr<CompilerDispatcherJob> job(new CompilerDispatcherJob(
+      isolate_, tracer_.get(), function, max_stack_size_));
+  std::pair<int, int> key(Script::cast(function->script())->id(),
+                          function->function_literal_id());
+  jobs_.insert(std::make_pair(key, std::move(job)));
+  return true;
+}
+
+bool CompilerDispatcher::IsEnqueued(Handle<SharedFunctionInfo> function) const {
+  return GetJobFor(function) != jobs_.end();
+}
+
+bool CompilerDispatcher::FinishNow(Handle<SharedFunctionInfo> function) {

[marja, 2016/12/12 12:25:01]

How would we use the return value? false can mean either that there was no job
in the queue (maybe a background task finished it just before the call) or that
the job failed. What would the return value used for?

There are 3 possible outcomes:
1. was not in the queue
2. was in the queue, we executed it and the compilation passed
3. was in the queue, we executed it and the compilation failed

and the return value can differentiate only between 2, so, depending on the
usage the grouping might be either (1, 2 & 3) (would have been my intuition) or
(1 & 3, 2) (like it is now).

[jochen (gone - plz use gerrit), 2016/12/12 12:34:37]

I added "UNREACHABLE()" to the "not in queue" case, as the caller should make
sure to first check whether the job is enqueued at all

+  JobMap::const_iterator job = GetJobFor(function);
+  if (job == jobs_.end()) return false;
+
+  // TODO(jochen): Check if there's an in-flight background task working on this
+  // job.
+  while (!IsDone(job->second.get())) {
+    DoNextStepOnMainThread(job->second.get());
+  }
+  bool result = job->second->status() != CompileJobStatus::kFailed;
+  jobs_.erase(job);
+  return result;
+}
+
+void CompilerDispatcher::Abort(Handle<SharedFunctionInfo> function,
+                               BlockingBehavior blocking) {
+  USE(blocking);
+  JobMap::const_iterator job = GetJobFor(function);
+  if (job == jobs_.end()) return;
+
+  // TODO(jochen): Check if there's an in-flight background task working on this
+  // job.
+  jobs_.erase(job);
+}
+
+void CompilerDispatcher::AbortAll(BlockingBehavior blocking) {
+  USE(blocking);
+  // TODO(jochen): Check if there's an in-flight background task working on this
+  // job.
+  jobs_.clear();
+}
+
+CompilerDispatcher::JobMap::const_iterator CompilerDispatcher::GetJobFor(
+    Handle<SharedFunctionInfo> shared) const {
+  if (!shared->script()->IsScript()) return jobs_.end();
+  std::pair<int, int> key(Script::cast(shared->script())->id(),
+                          shared->function_literal_id());
+  auto range = jobs_.equal_range(key);
+  for (auto job = range.first; job != range.second; ++job) {
+    if (job->second->IsAssociatedWith(shared)) return job;
+  }
+  return jobs_.end();
+}
+
+}  // namespace internal
+}  // namespace v8