Stack allocate lexical locals + hoist stack slots

src/scopes.cc

Index: src/scopes.cc
diff --git a/src/scopes.cc b/src/scopes.cc
index 364f2f1cf7ce88ca08e207172c1cba1613dbb3f7..e294fbf7f2b2582dbf9015af98a2d9c1fd2ac283 100644
--- a/src/scopes.cc
+++ b/src/scopes.cc
@@ -371,6 +371,7 @@ Scope* Scope::FinalizeBlockScope() {
   if (uses_arguments()) outer_scope_->RecordArgumentsUsage();
   if (uses_super_property()) outer_scope_->RecordSuperPropertyUsage();
   if (uses_this()) outer_scope_->RecordThisUsage();
+  if (scope_calls_eval_) outer_scope_->RecordEvalCall();
 
   return NULL;
 }
@@ -381,13 +382,13 @@ Variable* Scope::LookupLocal(const AstRawString* name) {
   if (result != NULL || scope_info_.is_null()) {
     return result;
   }
+  Handle<String> name_handle = name->string();
   // The Scope is backed up by ScopeInfo. This means it cannot operate in a
   // heap-independent mode, and all strings must be internalized immediately. So
   // it's ok to get the Handle<String> here.
-  Handle<String> name_handle = name->string();
   // If we have a serialized scope info, we might find the variable there.
   // There should be no local slot with the given name.
-  DCHECK(scope_info_->StackSlotIndex(*name_handle) < 0);
+  DCHECK(scope_info_->StackSlotIndex(*name_handle) < 0 || is_block_scope());
 
   // Check context slot lookup.
   VariableMode mode;
@@ -704,6 +705,7 @@ bool Scope::HasLazyCompilableOuterContext() const {
   bool found_non_trivial_declarations = false;
   for (const Scope* scope = outer; scope != NULL; scope = scope->outer_scope_) {
     if (scope->is_with_scope() && !found_non_trivial_declarations) return false;
+    if (scope->is_block_scope() && !scope->decls_.is_empty()) return false;
     if (scope->is_declaration_scope() && scope->num_heap_slots() > 0) {
       found_non_trivial_declarations = true;
     }
@@ -1286,7 +1288,7 @@ bool Scope::MustAllocateInContext(Variable* var) {
   if (has_forced_context_allocation()) return true;
   if (var->mode() == TEMPORARY) return false;
   if (var->mode() == INTERNAL) return true;
-  if (is_catch_scope() || is_block_scope() || is_module_scope()) return true;
+  if (is_catch_scope() || is_module_scope()) return true;
   if (is_script_scope() && IsLexicalVariableMode(var->mode())) return true;
   return var->has_forced_context_allocation() ||
       scope_calls_eval_ ||
@@ -1307,7 +1309,12 @@ bool Scope::HasArgumentsParameter(Isolate* isolate) {
 
 
 void Scope::AllocateStackSlot(Variable* var) {
-  var->AllocateTo(Variable::LOCAL, num_stack_slots_++);
+  if (is_block_scope()) {
+    auto decl_scope = DeclarationScope();
+    decl_scope->AllocateStackSlot(var);
+  } else {
+    var->AllocateTo(Variable::LOCAL, num_stack_slots_++);
+  }
 }
 
 
@@ -1384,13 +1391,17 @@ void Scope::AllocateNonParameterLocal(Isolate* isolate, Variable* var) {
   DCHECK(var->scope() == this);
   DCHECK(!var->IsVariable(isolate->factory()->dot_result_string()) ||
          !var->IsStackLocal());
+  // printf("Allocating:"); var->name()->Print();

[rossberg, 2015/04/17 15:16:27]

Clean up

[Dmitry Lomov (no reviews), 2015/04/20 11:53:21]

Done.

   if (var->IsUnallocated() && MustAllocate(var)) {
     if (MustAllocateInContext(var)) {
+      // printf(" to context\n");
       AllocateHeapSlot(var);
     } else {
+      // printf(" to stack\n");
       AllocateStackSlot(var);
     }
   }
+  // else { printf(" already allocated\n"); }
 }
 
 
@@ -1432,6 +1443,9 @@ void Scope::AllocateNonParameterLocals(Isolate* isolate) {
 
 
 void Scope::AllocateVariablesRecursively(Isolate* isolate) {
+  if (!already_resolved()) {
+    num_stack_slots_ = 0;
+  }
   // Allocate variables for inner scopes.
   for (int i = 0; i < inner_scopes_.length(); i++) {
     inner_scopes_[i]->AllocateVariablesRecursively(isolate);
@@ -1441,7 +1455,6 @@ void Scope::AllocateVariablesRecursively(Isolate* isolate) {
   // variables in inner scopes which might not had been resolved yet.
   if (already_resolved()) return;
   // The number of slots required for variables.
-  num_stack_slots_ = 0;
   num_heap_slots_ = Context::MIN_CONTEXT_SLOTS;
 
   // Allocate variables for this scope.