[compiler] Add baseline tier to compilation pipeline.

src/compiler.cc

 // Copyright 2012 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.h"
 
 #include <algorithm>
 
 #include "src/ast/ast-numbering.h"
 #include "src/ast/prettyprinter.h"
 #include "src/ast/scopeinfo.h"
 #include "src/ast/scopes.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
 #include "src/compilation-cache.h"
 #include "src/compiler/pipeline.h"
 #include "src/crankshaft/hydrogen.h"
 #include "src/debug/debug.h"
 #include "src/debug/liveedit.h"
 #include "src/deoptimizer.h"
+#include "src/frames-inl.h"
 #include "src/full-codegen/full-codegen.h"
 #include "src/interpreter/interpreter.h"
 #include "src/isolate-inl.h"
 #include "src/log-inl.h"
 #include "src/messages.h"
 #include "src/parsing/parser.h"
 #include "src/parsing/rewriter.h"
 #include "src/parsing/scanner-character-streams.h"
 #include "src/profiler/cpu-profiler.h"
 #include "src/runtime-profiler.h"
@@ skipping 552 matching lines @@
   VMState<COMPILER> state(info->isolate());
   PostponeInterruptsScope postpone(info->isolate());
 
   // Parse and update CompilationInfo with the results.
   if (!Parser::ParseStatic(info->parse_info())) return MaybeHandle<Code>();
   Handle<SharedFunctionInfo> shared = info->shared_info();
   DCHECK_EQ(shared->language_mode(), info->literal()->language_mode());
 
   // Compile either unoptimized code or bytecode for the interpreter.
   if (!CompileUnoptimizedCode(info)) return MaybeHandle<Code>();
-  RecordFunctionCompilation(Logger::LAZY_COMPILE_TAG, info);
 
   // Update the shared function info with the scope info.
   InstallSharedScopeInfo(info, shared);
 
   // Install compilation result on the shared function info
   InstallSharedCompilationResult(info, shared);
 
+  // Record the function compilation event.
+  RecordFunctionCompilation(Logger::LAZY_COMPILE_TAG, info);
+
   return info->code();
 }
 
 MUST_USE_RESULT MaybeHandle<Code> GetCodeFromOptimizedCodeMap(
     Handle<JSFunction> function, BailoutId osr_ast_id) {
   Handle<SharedFunctionInfo> shared(function->shared());
   DisallowHeapAllocation no_gc;
   CodeAndLiterals cached = shared->SearchOptimizedCodeMap(
       function->context()->native_context(), osr_ast_id);
   if (cached.code != nullptr) {
@@ skipping 187 matching lines @@
       PrintF("[found optimized code for ");
       function->ShortPrint();
       if (!osr_ast_id.IsNone()) {
         PrintF(" at OSR AST id %d", osr_ast_id.ToInt());
       }
       PrintF("]\n");
     }
     return cached_code;
   }
 
-  DCHECK(AllowCompilation::IsAllowed(isolate));
-
+  // Reset profiler ticks, function is no longer considered hot.
   if (shared->is_compiled()) {
     shared->code()->set_profiler_ticks(0);
   }
 
   // TODO(mstarzinger): We cannot properly deserialize a scope chain containing
   // an eval scope and hence would fail at parsing the eval source again.
   if (shared->disable_optimization_reason() == kEval) {
     return MaybeHandle<Code>();
   }
 
@@ skipping 33 matching lines @@
     }
   } else {
     info->set_osr_frame(osr_frame);
     if (GetOptimizedCodeNow(info.get())) return info->code();
   }
 
   if (isolate->has_pending_exception()) isolate->clear_pending_exception();
   return MaybeHandle<Code>();
 }
 
+class InterpreterActivationsFinder : public ThreadVisitor {
+ public:
+  SharedFunctionInfo* shared_;
+  bool has_activations_;
+
+  explicit InterpreterActivationsFinder(SharedFunctionInfo* shared)
+      : shared_(shared), has_activations_(false) {}
+
+  void VisitThread(Isolate* isolate, ThreadLocalTop* top) {
+    JavaScriptFrameIterator it(isolate, top);
+    for (; !it.done(); it.Advance()) {

[rmcilroy, 2016/04/22 10:02:57]

Also done when "has_activations_" ?

[Michael Starzinger, 2016/04/22 10:47:45]

Done.

+      JavaScriptFrame* frame = it.frame();
+      if (!frame->is_interpreted()) continue;
+      if (frame->function()->shared() == shared_) has_activations_ = true;
+    }
+  }
+};
+
+bool HasInterpreterActivations(Isolate* isolate, SharedFunctionInfo* shared) {
+  InterpreterActivationsFinder activations_finder(shared);
+  activations_finder.VisitThread(isolate, isolate->thread_local_top());
+  isolate->thread_manager()->IterateArchivedThreads(&activations_finder);
+  return activations_finder.has_activations_;
+}
+
+MaybeHandle<Code> GetBaselineCode(Handle<JSFunction> function) {
+  Isolate* isolate = function->GetIsolate();
+  VMState<COMPILER> state(isolate);
+  PostponeInterruptsScope postpone(isolate);
+  CompilationInfoWithZone info(function);
+
+  // Reset profiler ticks, function is no longer considered hot.
+  if (function->shared()->HasBytecodeArray()) {
+    function->shared()->set_profiler_ticks(0);
+  }
+
+  // TODO(4280): For now we do not switch to baseline code when the debugger
+  // might have created a copy of the bytecode with break slots.

[rmcilroy, 2016/04/22 10:02:57]

Is this a TODO - I though we were planning to always do this?

[Michael Starzinger, 2016/04/22 10:47:45]

Done. I don't have a concrete answer on whether we ever want to be able to debug
functions that are running in "unoptimized" as well as "baseline" code at the
same time. For now we certainly don't, you are right, hence removed the TODO.

+  if (function->shared()->HasDebugInfo()) {
+    return MaybeHandle<Code>();
+  }
+
+  // TODO(4280): For now we do not switch generators to baseline code because
+  // there might be suspended activations stored in generator objects on the
+  // heap. We could eventually go directly to TurboFan in this case.
+  if (function->shared()->is_generator()) {
+    return MaybeHandle<Code>();
+  }
+
+  // TODO(4280): For now we disable switching to baseline code in the presence
+  // of interpreter activations of the given function. The reasons are:
+  //  1) The debugger assumes each function is either full-code or bytecode.
+  //  2) The underlying bytecode is cleared below, breaking stack unwinding.
+  if (HasInterpreterActivations(isolate, function->shared())) {
+    if (FLAG_trace_opt) {
+      OFStream os(stdout);
+      os << "[unable to switch " << Brief(*function) << " due to activations]"
+         << std::endl;
+    }
+    return MaybeHandle<Code>();
+  }
+
+  if (FLAG_trace_opt) {
+    OFStream os(stdout);
+    os << "[switching method " << Brief(*function) << " to baseline code]"
+       << std::endl;
+  }
+
+  // Parse and update CompilationInfo with the results.
+  if (!Parser::ParseStatic(info.parse_info())) return MaybeHandle<Code>();
+  Handle<SharedFunctionInfo> shared = info.shared_info();
+  DCHECK_EQ(shared->language_mode(), info.literal()->language_mode());
+
+  // Compile unoptimized code using the full code generator.

[rmcilroy, 2016/04/22 10:02:57]

/s/unoptimzed/baseline

[Michael Starzinger, 2016/04/22 10:47:45]

Done.

+  if (!Compiler::Analyze(info.parse_info()) ||
+      !FullCodeGenerator::MakeCode(&info)) {
+    if (!isolate->has_pending_exception()) isolate->StackOverflow();
+    return MaybeHandle<Code>();
+  }
+
+  // TODO(4280): For now we play it safe and remove the bytecode array when we
+  // switch to baseline code. We might consider keeping around the bytecode so
+  // that it can be used as the "source of truth" eventually.
+  shared->ClearBytecodeArray();
+
+  // Update the shared function info with the scope info.
+  InstallSharedScopeInfo(&info, shared);
+
+  // Install compilation result on the shared function info
+  InstallSharedCompilationResult(&info, shared);
+
+  // Record the function compilation event.
+  RecordFunctionCompilation(Logger::LAZY_COMPILE_TAG, &info);
+
+  return info.code();
+}
+
 MaybeHandle<Code> GetLazyCode(Handle<JSFunction> function) {
   Isolate* isolate = function->GetIsolate();
   DCHECK(!isolate->has_pending_exception());
   DCHECK(!function->is_compiled());
   TimerEventScope<TimerEventCompileCode> compile_timer(isolate);
   TRACE_EVENT0("v8", "V8.CompileCode");
   AggregatedHistogramTimerScope timer(isolate->counters()->compile_lazy());
 
   if (FLAG_turbo_cache_shared_code) {
     Handle<Code> cached_code;
@@ skipping 209 matching lines @@
   // Install code on closure.
   function->ReplaceCode(*code);
 
   // Check postconditions on success.
   DCHECK(!isolate->has_pending_exception());
   DCHECK(function->shared()->is_compiled());
   DCHECK(function->is_compiled());
   return true;
 }
 
+bool Compiler::CompileBaseline(Handle<JSFunction> function) {
+  Isolate* isolate = function->GetIsolate();
+  DCHECK(AllowCompilation::IsAllowed(isolate));
+
+  // Start a compilation.
+  Handle<Code> code;
+  if (!GetBaselineCode(function).ToHandle(&code)) {
+    // Baseline generation failed, get unoptimized code.
+    DCHECK(function->shared()->is_compiled());
+    code = handle(function->shared()->code());
+    isolate->clear_pending_exception();
+  }
+
+  // Install code on closure.
+  function->ReplaceCode(*code);
+
+  // Check postconditions on success.
+  DCHECK(!isolate->has_pending_exception());
+  DCHECK(function->shared()->is_compiled());
+  DCHECK(function->is_compiled());
+  return true;
+}
+
 bool Compiler::CompileOptimized(Handle<JSFunction> function,
                                 ConcurrencyMode mode) {
   if (function->IsOptimized()) return true;
   Isolate* isolate = function->GetIsolate();
   DCHECK(AllowCompilation::IsAllowed(isolate));
 
   // Start a compilation.
   Handle<Code> code;
   if (!GetOptimizedCode(function, mode).ToHandle(&code)) {
     // Optimization failed, get unoptimized code.
@@ skipping 575 matching lines @@
     MaybeHandle<Code> code;
     if (cached.code != nullptr) code = handle(cached.code);
     Handle<Context> native_context(function->context()->native_context());
     SharedFunctionInfo::AddToOptimizedCodeMap(shared, native_context, code,
                                               literals, BailoutId::None());
   }
 }
 
 }  // namespace internal
 }  // namespace v8