[compiler] Ensure feedback vector before compiling.

This makes sure the type feedback vector is allocated and installed on
the SharedFunctionInfo before any of the compilers are being called.
Note that this now allows for an object state where a function is not
compiled but has a valid feedback vector is installed. This is working
as intended and supported by the rest of the system.

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/1857203002

Cr-Commit-Position: refs/heads/master@{#35265}

src/compiler.cc

@@ -143,12 +143,6 @@ CompilationInfo::CompilationInfo(ParseInfo* parse_info)
   if (FLAG_turbo_types) MarkAsTypingEnabled();
 
   if (has_shared_info()) {
-    if (shared_info()->is_compiled()) {
-      // We should initialize the CompilationInfo feedback vector from the
-      // passed in shared info, rather than creating a new one.
-      feedback_vector_ = Handle<TypeFeedbackVector>(
-          shared_info()->feedback_vector(), parse_info->isolate());
-    }
     if (shared_info()->never_compiled()) MarkAsFirstCompile();
   }
 }
@@ -222,20 +216,6 @@ bool CompilationInfo::ShouldSelfOptimize() {
 }
 
 
-void CompilationInfo::EnsureFeedbackVector() {
-  if (feedback_vector_.is_null()) {
-    Handle<TypeFeedbackMetadata> feedback_metadata =
-        TypeFeedbackMetadata::New(isolate(), literal()->feedback_vector_spec());
-    feedback_vector_ = TypeFeedbackVector::New(isolate(), feedback_metadata);
-  }
-
-  // It's very important that recompiles do not alter the structure of the
-  // type feedback vector.
-  CHECK(!feedback_vector_->metadata()->SpecDiffersFrom(
-      literal()->feedback_vector_spec()));
-}
-
-
 bool CompilationInfo::has_simple_parameters() {
   return scope()->has_simple_parameters();
 }
@@ -784,10 +764,30 @@ void RecordFunctionCompilation(Logger::LogEventsAndTags tag,
   }
 }
 
+void EnsureFeedbackVector(CompilationInfo* info) {
+  if (!info->has_shared_info()) return;
+
+  // If no type feedback vector exists, we create one now. At this point the
+  // AstNumbering pass has already run. Note that we should reuse any existing
+  // feedback vector rather than creating a new one.
+  if (info->shared_info()->feedback_vector()->is_empty()) {
+    Handle<TypeFeedbackMetadata> feedback_metadata = TypeFeedbackMetadata::New(
+        info->isolate(), info->literal()->feedback_vector_spec());
+    Handle<TypeFeedbackVector> feedback_vector =
+        TypeFeedbackVector::New(info->isolate(), feedback_metadata);
+    info->shared_info()->set_feedback_vector(*feedback_vector);
+  }
+
+  // It's very important that recompiles do not alter the structure of the type
+  // feedback vector. Verify that the structure fits the function literal.
+  CHECK(!info->shared_info()->feedback_vector()->metadata()->SpecDiffersFrom(
+      info->literal()->feedback_vector_spec()));
+}
+
 bool CompileUnoptimizedCode(CompilationInfo* info) {
   DCHECK(AllowCompilation::IsAllowed(info->isolate()));
   if (!Compiler::Analyze(info->parse_info()) ||
-      !(info->EnsureFeedbackVector(), FullCodeGenerator::MakeCode(info))) {
+      !(EnsureFeedbackVector(info), FullCodeGenerator::MakeCode(info))) {
     Isolate* isolate = info->isolate();
     if (!isolate->has_pending_exception()) isolate->StackOverflow();
     return false;
@@ -839,7 +839,7 @@ int CodeAndMetadataSize(CompilationInfo* info) {
 
 bool GenerateBaselineCode(CompilationInfo* info) {
   bool success;
-  info->EnsureFeedbackVector();
+  EnsureFeedbackVector(info);
   if (FLAG_ignition && UseIgnition(info)) {
     success = interpreter::Interpreter::MakeBytecode(info);
   } else {
@@ -872,7 +872,6 @@ void InstallBaselineCompilationResult(CompilationInfo* info,
   DCHECK(!info->code().is_null());
   shared->ReplaceCode(*info->code());
   shared->set_scope_info(*scope_info);
-  shared->set_feedback_vector(*info->feedback_vector());
   if (info->has_bytecode_array()) {
     DCHECK(!shared->HasBytecodeArray());  // Only compiled once.
     shared->set_bytecode_array(*info->bytecode_array());
@@ -1460,11 +1459,10 @@ bool Compiler::EnsureDeoptimizationSupport(CompilationInfo* info) {
         shared->code()->has_reloc_info_for_serialization()) {
       unoptimized.PrepareForSerializing();
     }
-    unoptimized.EnsureFeedbackVector();
+    EnsureFeedbackVector(&unoptimized);
     if (!FullCodeGenerator::MakeCode(&unoptimized)) return false;
 
     shared->EnableDeoptimizationSupport(*unoptimized.code());
-    shared->set_feedback_vector(*unoptimized.feedback_vector());
 
     info->MarkAsCompiled();
 
@@ -1498,11 +1496,6 @@ void Compiler::CompileForLiveEdit(Handle<Script> script) {
 
   LiveEditFunctionTracker tracker(info.isolate(), parse_info.literal());
   if (!CompileUnoptimizedCode(&info)) return;
-  if (info.has_shared_info()) {
-    Handle<ScopeInfo> scope_info =
-        ScopeInfo::Create(info.isolate(), info.zone(), info.scope());
-    info.shared_info()->set_scope_info(*scope_info);
-  }
   tracker.RecordRootFunctionInfo(info.code());
 }
 

src/compiler.h

@@ -322,10 +322,6 @@ class CompilationInfo {
            output_code_kind() == Code::FUNCTION;
   }
 
-  void EnsureFeedbackVector();
-  Handle<TypeFeedbackVector> feedback_vector() const {
-    return feedback_vector_;
-  }
   void SetCode(Handle<Code> code) { code_ = code; }
 
   void SetBytecodeArray(Handle<BytecodeArray> bytecode_array) {
@@ -534,9 +530,6 @@ class CompilationInfo {
   // The compiled code.
   Handle<Code> code_;
 
-  // Used by codegen, ultimately kept rooted by the SharedFunctionInfo.
-  Handle<TypeFeedbackVector> feedback_vector_;
-
   // Compilation mode flag and whether deoptimization is allowed.
   Mode mode_;
   BailoutId osr_ast_id_;

src/interpreter/bytecode-generator.cc

@@ -3156,7 +3156,7 @@ LanguageMode BytecodeGenerator::language_mode() const {
 
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
-  return info()->feedback_vector()->GetIndex(slot);
+  return info()->shared_info()->feedback_vector()->GetIndex(slot);
 }
 
 }  // namespace interpreter