[compiler] Allow optimization of top-level eval code.

This allows for top-level eval code to be parsed properly before doing
optimization. It uses the same kind of re-parsing we already perform
when compiling code for debugging.

R=bmeurer@chromium.org

Review-Url: https://codereview.chromium.org/1884143003
Cr-Commit-Position: refs/heads/master@{#36014}

src/compiler.cc

@@ -418,6 +418,12 @@ void CompilationJob::RecordOptimizationStats() {
 
 namespace {
 
+bool IsEvalToplevel(Handle<SharedFunctionInfo> shared) {
+  return shared->is_toplevel() && shared->script()->IsScript() &&
+         Script::cast(shared->script())->compilation_type() ==
+             Script::COMPILATION_TYPE_EVAL;
+}
+
 void RecordFunctionCompilation(Logger::LogEventsAndTags tag,
                                CompilationInfo* info) {
   // Log the code generation. If source information is available include
@@ -765,12 +771,6 @@ MaybeHandle<Code> GetOptimizedCode(Handle<JSFunction> function,
     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>();
-  }
-
   VMState<COMPILER> state(isolate);
   DCHECK(!isolate->has_pending_exception());
   PostponeInterruptsScope postpone(isolate);
@@ -779,6 +779,7 @@ MaybeHandle<Code> GetOptimizedCode(Handle<JSFunction> function,
       use_turbofan ? compiler::Pipeline::NewCompilationJob(function)
                    : new HCompilationJob(function));
   CompilationInfo* info = job->info();
+  ParseInfo* parse_info = info->parse_info();
 
   info->SetOptimizingForOsr(osr_ast_id);
 
@@ -813,6 +814,14 @@ MaybeHandle<Code> GetOptimizedCode(Handle<JSFunction> function,
     info->MarkAsOptimizeFromBytecode();
   }
 
+  if (IsEvalToplevel(shared)) {
+    parse_info->set_eval();
+    if (function->context()->IsNativeContext()) parse_info->set_global();
+    parse_info->set_toplevel();
+    parse_info->set_allow_lazy_parsing(false);
+    parse_info->set_lazy(false);
+  }
+
   if (mode == Compiler::CONCURRENT) {
     if (GetOptimizedCodeLater(job.get())) {
       job.Detach();   // The background recompile job owns this now.
@@ -1001,12 +1010,6 @@ MaybeHandle<Code> GetLazyCode(Handle<JSFunction> function) {
 }
 
 
-inline bool IsEvalToplevel(Handle<SharedFunctionInfo> shared) {
-  return shared->is_toplevel() && shared->script()->IsScript() &&
-         Script::cast(shared->script())->compilation_type() ==
-             Script::COMPILATION_TYPE_EVAL;
-}
-
 Handle<SharedFunctionInfo> NewSharedFunctionInfoForLiteral(
     Isolate* isolate, FunctionLiteral* literal, Handle<Script> script) {
   Handle<Code> code = isolate->builtins()->CompileLazy();

src/compiler/ast-graph-builder.cc

@@ -492,6 +492,12 @@ Node* AstGraphBuilder::GetFunctionClosureForContext() {
     // Contexts nested in the native context have a canonical empty function as
     // their closure, not the anonymous closure containing the global code.
     return BuildLoadNativeContextField(Context::CLOSURE_INDEX);
+  } else if (closure_scope->is_eval_scope()) {
+    // Contexts nested inside eval code have the same closure as the context
+    // calling eval, not the anonymous closure containing the eval code.
+    const Operator* op =
+        javascript()->LoadContext(0, Context::CLOSURE_INDEX, false);
+    return NewNode(op, current_context());
   } else {
     DCHECK(closure_scope->is_function_scope());
     return GetFunctionClosure();
@@ -1109,7 +1115,9 @@ void AstGraphBuilder::VisitVariableDeclaration(VariableDeclaration* decl) {
       }
       break;
     case VariableLocation::LOOKUP:
-      UNIMPLEMENTED();
+      // TODO(mstarzinger): Implement this case.
+      SetStackOverflow();
+      break;
   }
 }
 
@@ -1142,7 +1150,9 @@ void AstGraphBuilder::VisitFunctionDeclaration(FunctionDeclaration* decl) {
       break;
     }
     case VariableLocation::LOOKUP:
-      UNIMPLEMENTED();
+      // TODO(mstarzinger): Implement this case.
+      SetStackOverflow();
+      break;
   }
 }
 
@@ -3185,7 +3195,7 @@ Node* AstGraphBuilder::BuildLocalActivationContext(Node* context) {
 
 
 Node* AstGraphBuilder::BuildLocalFunctionContext(Scope* scope) {
-  DCHECK(scope->is_function_scope());
+  DCHECK(scope->is_function_scope() || scope->is_eval_scope());
 
   // Allocate a new local context.
   int slot_count = scope->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;

src/objects.cc

@@ -12355,7 +12355,11 @@ MaybeHandle<SharedFunctionInfo> Script::FindSharedFunctionInfo(
   SharedFunctionInfo* shared;
   while ((shared = iterator.Next<SharedFunctionInfo>())) {
     if (fun->function_token_position() == shared->function_token_position() &&
-        fun->start_position() == shared->start_position()) {
+        fun->start_position() == shared->start_position() &&
+        fun->end_position() == shared->end_position()) {
+      // This method is not used to find top-level SharedFunctionInfo objects,
+      // verify that above checks are sufficient to distinguish top-level code.
+      DCHECK(!shared->is_toplevel());
       return Handle<SharedFunctionInfo>(shared);
     }
   }

test/mozilla/mozilla.status

@@ -64,6 +64,8 @@
   'js1_5/Regress/regress-111557': [PASS, NO_VARIANTS],
   'js1_5/Regress/regress-155081': [PASS, NO_VARIANTS],
   'js1_5/Regress/regress-155081-2': [PASS, NO_VARIANTS],
+  'js1_5/Regress/regress-159334': [PASS, NO_VARIANTS],
+  'js1_5/Regress/regress-321971': [PASS, NO_VARIANTS],
   'js1_5/Regress/regress-451322': [PASS, NO_VARIANTS],
 
   # TODO(turbofan): Large switch statements crash.