[compiler] Allocate SharedFunctionInfo before compile.

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"
@@ skipping 836 matching lines @@
 static bool CompileBaselineCode(CompilationInfo* info) {
   DCHECK(AllowCompilation::IsAllowed(info->isolate()));
   if (!Compiler::Analyze(info->parse_info()) || !GenerateBaselineCode(info)) {
     Isolate* isolate = info->isolate();
     if (!isolate->has_pending_exception()) isolate->StackOverflow();
     return false;
   }
   return true;
 }
 
+static void InstallBaselineCompilationResult(CompilationInfo* info,
+                                             Handle<SharedFunctionInfo> shared,
+                                             Handle<ScopeInfo> scope_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());
+  }
+}
 
 MUST_USE_RESULT static MaybeHandle<Code> GetUnoptimizedCodeCommon(
     CompilationInfo* info) {
   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();
   FunctionLiteral* lit = info->literal();
   DCHECK_EQ(shared->language_mode(), lit->language_mode());
   SetExpectedNofPropertiesFromEstimate(shared, lit->expected_property_count());
   MaybeDisableOptimization(shared, lit->dont_optimize_reason());
 
   // Compile either unoptimized code or bytecode for the interpreter.
   if (!CompileBaselineCode(info)) return MaybeHandle<Code>();
   RecordFunctionCompilation(Logger::LAZY_COMPILE_TAG, info, shared);
 
   // Update the shared function info with the scope info. Allocating the
   // ScopeInfo object may cause a GC.
   Handle<ScopeInfo> scope_info =
       ScopeInfo::Create(info->isolate(), info->zone(), info->scope());
-  shared->set_scope_info(*scope_info);
 
-  // Update the code and feedback vector for the shared function info.
-  shared->ReplaceCode(*info->code());
-  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());
-  }
+  // Install compilation result on the shared function info
+  InstallBaselineCompilationResult(info, shared, scope_info);
 
   return info->code();
 }
 
 
 MUST_USE_RESULT static MaybeHandle<Code> GetCodeFromOptimizedCodeMap(
     Handle<JSFunction> function, BailoutId osr_ast_id) {
   Handle<SharedFunctionInfo> shared(function->shared());
   DisallowHeapAllocation no_gc;
   CodeAndLiterals cached = shared->SearchOptimizedCodeMap(
@@ skipping 471 matching lines @@
   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());
 }
 
+static Handle<SharedFunctionInfo> NewSharedFunctionInfoForLiteral(
+    Isolate* isolate, FunctionLiteral* literal, Handle<Script> script) {
+  Handle<Code> code = isolate->builtins()->CompileLazy();
+  Handle<ScopeInfo> scope_info = handle(ScopeInfo::Empty(isolate));
+  Handle<SharedFunctionInfo> result = isolate->factory()->NewSharedFunctionInfo(
+      literal->name(), literal->materialized_literal_count(), literal->kind(),
+      code, scope_info);
+  SharedFunctionInfo::InitFromFunctionLiteral(result, literal);
+  SharedFunctionInfo::SetScript(result, script);
+  return result;
+}
 
 static Handle<SharedFunctionInfo> CompileToplevel(CompilationInfo* info) {
   Isolate* isolate = info->isolate();
   TimerEventScope<TimerEventCompileCode> timer(isolate);
   TRACE_EVENT0("v8", "V8.CompileCode");
   PostponeInterruptsScope postpone(isolate);
   DCHECK(!isolate->native_context().is_null());
   ParseInfo* parse_info = info->parse_info();
   Handle<Script> script = parse_info->script();
 
@@ skipping 49 matching lines @@
 
     // Measure how long it takes to do the compilation; only take the
     // rest of the function into account to avoid overlap with the
     // parsing statistics.
     HistogramTimer* rate = info->is_eval()
           ? info->isolate()->counters()->compile_eval()
           : info->isolate()->counters()->compile();
     HistogramTimerScope timer(rate);
     TRACE_EVENT0("v8", info->is_eval() ? "V8.CompileEval" : "V8.Compile");
 
+    // Allocate a shared function info object.
+    DCHECK_EQ(RelocInfo::kNoPosition, lit->function_token_position());
+    result = NewSharedFunctionInfoForLiteral(isolate, lit, script);
+    result->set_is_toplevel(true);
+    if (info->is_eval()) {
+      // Eval scripts cannot be (re-)compiled without context.
+      result->set_allows_lazy_compilation_without_context(false);
+    }
+
     // Compile the code.
     if (!CompileBaselineCode(info)) {
       return Handle<SharedFunctionInfo>::null();
     }
 
-    // Allocate function.
-    DCHECK(!info->code().is_null());
-    result = isolate->factory()->NewSharedFunctionInfo(
-        lit->name(), lit->materialized_literal_count(), lit->kind(),
-        info->code(),
-        ScopeInfo::Create(info->isolate(), info->zone(), info->scope()),
-        info->feedback_vector());
-    if (info->has_bytecode_array()) {
-      DCHECK(!result->HasBytecodeArray());  // Only compiled once.
-      result->set_bytecode_array(*info->bytecode_array());
-    }
-
-    DCHECK_EQ(RelocInfo::kNoPosition, lit->function_token_position());
-    SharedFunctionInfo::InitFromFunctionLiteral(result, lit);
-    SharedFunctionInfo::SetScript(result, script);
-    result->set_is_toplevel(true);
-    if (info->is_eval()) {
-      // Eval scripts cannot be (re-)compiled without context.
-      result->set_allows_lazy_compilation_without_context(false);
-    }
+    // Install compilation result on the shared function info
+    Handle<ScopeInfo> scope_info =
+        ScopeInfo::Create(info->isolate(), info->zone(), info->scope());
+    InstallBaselineCompilationResult(info, result, scope_info);
 
     Handle<String> script_name =
         script->name()->IsString()
             ? Handle<String>(String::cast(script->name()))
             : isolate->factory()->empty_string();
     Logger::LogEventsAndTags log_tag = info->is_eval()
         ? Logger::EVAL_TAG
         : Logger::ToNativeByScript(Logger::SCRIPT_TAG, *script);
 
     PROFILE(isolate, CodeCreateEvent(log_tag, *info->abstract_code(), *result,
@@ skipping 254 matching lines @@
   // compiled, continue to decide whether to eagerly compile.
   // Carry on if we are compiling eager to obtain code for debugging,
   // unless we already have code with debut break slots.
   Handle<SharedFunctionInfo> existing;
   if (maybe_existing.ToHandle(&existing) && existing->is_compiled()) {
     if (!outer_info->is_debug() || existing->HasDebugCode()) {
       return existing;
     }
   }
 
+  // Allocate a shared function info object.
+  Handle<SharedFunctionInfo> result;
+  if (!maybe_existing.ToHandle(&result)) {
+    result = NewSharedFunctionInfoForLiteral(isolate, literal, script);
+    result->set_is_toplevel(false);
+  }
+
   Zone zone;
   ParseInfo parse_info(&zone, script);
   CompilationInfo info(&parse_info);
   parse_info.set_literal(literal);
   parse_info.set_scope(literal->scope());
   parse_info.set_language_mode(literal->scope()->language_mode());
   if (outer_info->will_serialize()) info.PrepareForSerializing();
   if (outer_info->is_first_compile()) info.MarkAsFirstCompile();
   if (outer_info->is_debug()) info.MarkAsDebug();
 
@@ skipping 15 matching lines @@
                     (!info.is_debug() || allow_lazy_without_ctx);
 
   bool lazy = FLAG_lazy && allow_lazy && !literal->should_eager_compile();
 
   // Consider compiling eagerly when targeting the code cache.
   lazy &= !(FLAG_serialize_eager && info.will_serialize());
 
   // Generate code
   TimerEventScope<TimerEventCompileCode> timer(isolate);
   TRACE_EVENT0("v8", "V8.CompileCode");
-  Handle<ScopeInfo> scope_info;
   if (lazy) {
-    Handle<Code> code = isolate->builtins()->CompileLazy();
-    info.SetCode(code);
-    // There's no need in theory for a lazy-compiled function to have a type
-    // feedback vector, but some parts of the system expect all
-    // SharedFunctionInfo instances to have one.  The size of the vector depends
-    // on how many feedback-needing nodes are in the tree, and when lazily
-    // parsing we might not know that, if this function was never parsed before.
-    // In that case the vector will be replaced the next time MakeCode is
-    // called.
-    info.EnsureFeedbackVector();
-    scope_info = Handle<ScopeInfo>(ScopeInfo::Empty(isolate));
+    info.SetCode(isolate->builtins()->CompileLazy());
   } else if (Renumber(info.parse_info()) && GenerateBaselineCode(&info)) {
     // Code generation will ensure that the feedback vector is present and
     // appropriately sized.
     DCHECK(!info.code().is_null());
-    scope_info = ScopeInfo::Create(info.isolate(), info.zone(), info.scope());
+    Handle<ScopeInfo> scope_info =
+        ScopeInfo::Create(info.isolate(), info.zone(), info.scope());
     if (literal->should_eager_compile() &&
         literal->should_be_used_once_hint()) {
       info.code()->MarkToBeExecutedOnce(isolate);
     }
+    // Assert that we are not overwriting (possibly patched) debug code.
+    DCHECK(!result->HasDebugCode());
+    // Install compilation result on the shared function info.
+    InstallBaselineCompilationResult(&info, result, scope_info);
   } else {
     return Handle<SharedFunctionInfo>::null();
   }
 
   if (maybe_existing.is_null()) {
-    // Create a shared function info object.
-    Handle<SharedFunctionInfo> result =
-        isolate->factory()->NewSharedFunctionInfo(
-            literal->name(), literal->materialized_literal_count(),
-            literal->kind(), info.code(), scope_info, info.feedback_vector());
-    if (info.has_bytecode_array()) {
-      DCHECK(!result->HasBytecodeArray());  // Only compiled once.
-      result->set_bytecode_array(*info.bytecode_array());
-    }
-
-    SharedFunctionInfo::InitFromFunctionLiteral(result, literal);
-    SharedFunctionInfo::SetScript(result, script);
-    result->set_is_toplevel(false);
     // If the outer function has been compiled before, we cannot be sure that
     // shared function info for this function literal has been created for the
     // first time. It may have already been compiled previously.
     result->set_never_compiled(outer_info->is_first_compile() && lazy);
 
     RecordFunctionCompilation(Logger::FUNCTION_TAG, &info, result);
     result->set_allows_lazy_compilation(literal->AllowsLazyCompilation());
     result->set_allows_lazy_compilation_without_context(allow_lazy_without_ctx);
 
     // Set the expected number of properties for instances and return
     // the resulting function.
     SetExpectedNofPropertiesFromEstimate(result,
                                          literal->expected_property_count());
     live_edit_tracker.RecordFunctionInfo(result, literal, info.zone());
-    return result;
-  } else if (!lazy) {
-    // Assert that we are not overwriting (possibly patched) debug code.
-    DCHECK(!existing->HasDebugCode());

[Yang, 2016/03/18 06:35:25]

Can we move this check to InstallBaselineCompilationResult?

[Michael Starzinger, 2016/03/18 10:05:17]

Done.

-    existing->ReplaceCode(*info.code());
-    existing->set_scope_info(*scope_info);
-    existing->set_feedback_vector(*info.feedback_vector());
   }
-  return existing;
+
+  return result;
 }
 
 Handle<SharedFunctionInfo> Compiler::GetSharedFunctionInfoForNative(
     v8::Extension* extension, Handle<String> name) {
   Isolate* isolate = name->GetIsolate();
   v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate);
 
   // Compute the function template for the native function.
   v8::Local<v8::FunctionTemplate> fun_template =
       extension->GetNativeFunctionTemplate(v8_isolate,
                                            v8::Utils::ToLocal(name));
   DCHECK(!fun_template.IsEmpty());
 
   // Instantiate the function and create a shared function info from it.
   Handle<JSFunction> fun = Handle<JSFunction>::cast(Utils::OpenHandle(
       *fun_template->GetFunction(v8_isolate->GetCurrentContext())
            .ToLocalChecked()));
   const int literals = fun->NumberOfLiterals();
   Handle<Code> code = Handle<Code>(fun->shared()->code());
   Handle<Code> construct_stub = Handle<Code>(fun->shared()->construct_stub());
   Handle<SharedFunctionInfo> shared = isolate->factory()->NewSharedFunctionInfo(
       name, literals, FunctionKind::kNormalFunction, code,
-      Handle<ScopeInfo>(fun->shared()->scope_info()),
-      Handle<TypeFeedbackVector>(fun->shared()->feedback_vector()));
+      Handle<ScopeInfo>(fun->shared()->scope_info()));
   shared->set_construct_stub(*construct_stub);
+  shared->set_feedback_vector(fun->shared()->feedback_vector());
 
   // Copy the function data to the shared function info.
   shared->set_function_data(fun->shared()->function_data());
   int parameters = fun->shared()->internal_formal_parameter_count();
   shared->set_internal_formal_parameter_count(parameters);
 
   return shared;
 }
 
 MaybeHandle<Code> Compiler::GetOptimizedCodeForOSR(Handle<JSFunction> function,
@@ skipping 92 matching lines @@
 
 #if DEBUG
 void CompilationInfo::PrintAstForTesting() {
   PrintF("--- Source from AST ---\n%s\n",
          PrettyPrinter(isolate()).PrintProgram(literal()));
 }
 #endif
 
 }  // namespace internal
 }  // namespace v8