[Interpreter] Create ScopeInfos in ast-numbering phase.

src/ast/ast-numbering.cc

Index: src/ast/ast-numbering.cc
diff --git a/src/ast/ast-numbering.cc b/src/ast/ast-numbering.cc
index 100814691f8cb1a3428aab1fcc5b0a9d7756c7de..1b9905a2c6c1d0d23076e965f2983a0d4f6b07d6 100644
--- a/src/ast/ast-numbering.cc
+++ b/src/ast/ast-numbering.cc
@@ -233,6 +233,14 @@ void AstNumberingVisitor::VisitCountOperation(CountOperation* node) {
 void AstNumberingVisitor::VisitBlock(Block* node) {
   IncrementNodeCount();
   node->set_base_id(ReserveIdRange(Block::num_ids()));
+
+  if (FLAG_ignition && node->scope() != nullptr &&

[Michael Starzinger, 2016/08/09 07:38:26]

Just for posterity: We could consider adding Block::PrepareScopeInfo(Isolate*)
to bundle the predicate with the AST node. But for now lets stick with the
current version until the approach stabilizes.

+      node->scope()->NeedsContext()) {
+    // Create ScopeInfo while on the main thread to avoid allocation during
+    // potentially concurrent bytecode generation.
+    node->scope()->GetScopeInfo(isolate_);
+  }
+
   if (node->scope() != NULL) VisitDeclarations(node->scope()->declarations());
   VisitStatements(node->statements());
 }
@@ -572,6 +580,12 @@ bool AstNumberingVisitor::Renumber(FunctionLiteral* node) {
     DisableCrankshaft(kRestParameter);
   }
 
+  if (FLAG_ignition && scope->NeedsContext() && scope->is_script_scope()) {
+    // Create ScopeInfo while on the main thread to avoid allocation during
+    // potentially concurrent bytecode generation.
+    node->scope()->GetScopeInfo(isolate_);
+  }
+
   if (IsGeneratorFunction(node->kind()) || IsAsyncFunction(node->kind())) {
     // TODO(neis): We may want to allow Turbofan optimization here if
     // --turbo-from-bytecode is set and we know that Ignition is used.