PreParser: track variable declarations and parameters

src/ast/scopes.cc

Index: src/ast/scopes.cc
diff --git a/src/ast/scopes.cc b/src/ast/scopes.cc
index fc020ccefb81466a40ad04295019d6b9a226ae65..16ef6a5409efab551542eec2881a7c7519cfc153 100644
--- a/src/ast/scopes.cc
+++ b/src/ast/scopes.cc
@@ -15,6 +15,10 @@
 namespace v8 {
 namespace internal {
 
+namespace {
+void* kDummyPreParserVariable = reinterpret_cast<void*>(0x1);
+}  // namespace
+
 // ----------------------------------------------------------------------------
 // Implementation of LocalsMap
 //
@@ -49,6 +53,17 @@ Variable* VariableMap::Declare(Zone* zone, Scope* scope,
   return reinterpret_cast<Variable*>(p->value);
 }
 
+void VariableMap::DeclareName(Zone* zone, const AstRawString* name) {
+  Entry* p =
+      ZoneHashMap::LookupOrInsert(const_cast<AstRawString*>(name), name->hash(),
+                                  ZoneAllocationPolicy(zone));
+  if (p->value == nullptr) {
+    // The variable has not been declared yet -> insert it.
+    DCHECK_EQ(name, p->key);
+    p->value = kDummyPreParserVariable;
+  }
+}
+
 void VariableMap::Remove(Variable* var) {
   const AstRawString* name = var->raw_name();
   ZoneHashMap::Remove(const_cast<AstRawString*>(name), name->hash());
@@ -263,7 +278,14 @@ void DeclarationScope::SetDefaults() {
   arguments_ = nullptr;
   this_function_ = nullptr;
   should_eager_compile_ = false;
-  is_lazily_parsed_ = false;
+  was_lazily_parsed_ = false;
+#ifdef DEBUG
+  DeclarationScope* outer_declaration_scope =
+      outer_scope_ ? outer_scope_->GetDeclarationScope() : nullptr;
+  is_being_lazily_parsed_ =
+      outer_declaration_scope ? outer_declaration_scope->is_being_lazily_parsed_
+                              : false;
+#endif
 }
 
 void Scope::SetDefaults() {
@@ -305,7 +327,7 @@ bool DeclarationScope::ShouldEagerCompile() const {
 }
 
 void DeclarationScope::set_should_eager_compile() {
-  should_eager_compile_ = !is_lazily_parsed_;
+  should_eager_compile_ = !was_lazily_parsed_;
 }
 
 void DeclarationScope::set_asm_module() {
@@ -866,6 +888,8 @@ Variable* DeclarationScope::DeclareParameter(
   DCHECK(is_function_scope() || is_module_scope());
   DCHECK(!has_rest_);
   DCHECK(!is_optional || !is_rest);
+  DCHECK(!is_being_lazily_parsed_);
+  DCHECK(!was_lazily_parsed_);
   Variable* var;
   if (mode == TEMPORARY) {
     var = NewTemporary(name);
@@ -890,6 +914,8 @@ Variable* Scope::DeclareLocal(const AstRawString* name, VariableMode mode,
   // introduced during variable allocation, and TEMPORARY variables are
   // allocated via NewTemporary().
   DCHECK(IsDeclaredVariableMode(mode));
+  DCHECK(!GetDeclarationScope()->is_being_lazily_parsed());
+  DCHECK(!GetDeclarationScope()->was_lazily_parsed());
   return Declare(zone(), name, mode, kind, init_flag, maybe_assigned_flag);
 }
 
@@ -899,6 +925,8 @@ Variable* Scope::DeclareVariable(
     bool* sloppy_mode_block_scope_function_redefinition, bool* ok) {
   DCHECK(IsDeclaredVariableMode(mode));
   DCHECK(!already_resolved_);
+  DCHECK(!GetDeclarationScope()->is_being_lazily_parsed());
+  DCHECK(!GetDeclarationScope()->was_lazily_parsed());
 
   if (mode == VAR && !is_declaration_scope()) {
     return GetDeclarationScope()->DeclareVariable(
@@ -997,6 +1025,26 @@ Variable* Scope::DeclareVariable(
   return var;
 }
 
+void Scope::DeclareVariableName(const AstRawString* name, VariableMode mode) {
+  DCHECK(IsDeclaredVariableMode(mode));
+  DCHECK(!already_resolved_);
+  DCHECK(GetDeclarationScope()->is_being_lazily_parsed());
+
+  if (mode == VAR && !is_declaration_scope()) {
+    return GetDeclarationScope()->DeclareVariableName(name, mode);
+  }
+  DCHECK(!is_catch_scope());
+  DCHECK(!is_with_scope());
+  DCHECK(!is_eval_scope());
+  DCHECK(is_declaration_scope() ||
+         (IsLexicalVariableMode(mode) && is_block_scope()));
+
+  // Declare the variable in the declaration scope.
+  if (LookupLocal(name) == nullptr) {
+    variables_.DeclareName(zone(), name);
+  }
+}
+
 VariableProxy* Scope::NewUnresolved(AstNodeFactory* factory,
                                     const AstRawString* name,
                                     int start_position, VariableKind kind) {
@@ -1271,7 +1319,7 @@ Scope* Scope::GetOuterScopeWithContext() {
 
 Handle<StringSet> DeclarationScope::CollectNonLocals(
     ParseInfo* info, Handle<StringSet> non_locals) {
-  VariableProxy* free_variables = FetchFreeVariables(this, true, info);
+  VariableProxy* free_variables = FetchFreeVariables(this, info);
   for (VariableProxy* proxy = free_variables; proxy != nullptr;
        proxy = proxy->next_unresolved()) {
     non_locals = StringSet::Add(non_locals, proxy->name());
@@ -1307,9 +1355,10 @@ void DeclarationScope::ResetAfterPreparsing(AstValueFactory* ast_value_factory,
 
 #ifdef DEBUG
   needs_migration_ = false;
+  is_being_lazily_parsed_ = false;
 #endif
 
-  is_lazily_parsed_ = !aborted;
+  was_lazily_parsed_ = !aborted;
 }
 
 void DeclarationScope::AnalyzePartially(AstNodeFactory* ast_node_factory) {
@@ -1320,9 +1369,8 @@ void DeclarationScope::AnalyzePartially(AstNodeFactory* ast_node_factory) {
     // Try to resolve unresolved variables for this Scope and migrate those
     // which cannot be resolved inside. It doesn't make sense to try to resolve
     // them in the outer Scopes here, because they are incomplete.
-    for (VariableProxy* proxy =
-             FetchFreeVariables(this, !FLAG_lazy_inner_functions);
-         proxy != nullptr; proxy = proxy->next_unresolved()) {
+    for (VariableProxy* proxy = FetchFreeVariables(this); proxy != nullptr;
+         proxy = proxy->next_unresolved()) {
       DCHECK(!proxy->is_resolved());
       VariableProxy* copy = ast_node_factory->CopyVariableProxy(proxy);
       copy->set_next_unresolved(unresolved);
@@ -1490,7 +1538,7 @@ void Scope::Print(int n) {
   if (inner_scope_calls_eval_) Indent(n1, "// inner scope calls 'eval'\n");
   if (is_declaration_scope()) {
     DeclarationScope* scope = AsDeclarationScope();
-    if (scope->is_lazily_parsed()) Indent(n1, "// lazily parsed\n");
+    if (scope->was_lazily_parsed()) Indent(n1, "// lazily parsed\n");
     if (scope->ShouldEagerCompile()) Indent(n1, "// will be compiled\n");
   }
   if (num_stack_slots_ > 0) {
@@ -1543,7 +1591,7 @@ void Scope::CheckZones() {
   DCHECK(!needs_migration_);
   for (Scope* scope = inner_scope_; scope != nullptr; scope = scope->sibling_) {
     if (scope->is_declaration_scope() &&
-        scope->AsDeclarationScope()->is_lazily_parsed()) {
+        scope->AsDeclarationScope()->was_lazily_parsed()) {
       DCHECK_NULL(scope->zone());
       DCHECK_NULL(scope->inner_scope_);
       continue;
@@ -1599,6 +1647,13 @@ Variable* Scope::LookupRecursive(VariableProxy* proxy, Scope* outer_scope_end) {
   // The variable could not be resolved statically.
   if (var == nullptr) return var;
 
+  // TODO(marja): Separate LookupRecursive for preparsed scopes better.
+  if (var == kDummyPreParserVariable) {
+    DCHECK(GetDeclarationScope()->is_being_lazily_parsed());
+    DCHECK(FLAG_lazy_inner_functions);
+    return var;
+  }
+
   if (is_function_scope() && !var->is_dynamic()) {
     var->ForceContextAllocation();
   }
@@ -1738,7 +1793,7 @@ void Scope::ResolveVariablesRecursively(ParseInfo* info) {
   // Lazy parsed declaration scopes are already partially analyzed. If there are
   // unresolved references remaining, they just need to be resolved in outer
   // scopes.
-  if (is_declaration_scope() && AsDeclarationScope()->is_lazily_parsed()) {
+  if (is_declaration_scope() && AsDeclarationScope()->was_lazily_parsed()) {
     DCHECK(variables_.occupancy() == 0);
     for (VariableProxy* proxy = unresolved_; proxy != nullptr;
          proxy = proxy->next_unresolved()) {
@@ -1765,34 +1820,34 @@ void Scope::ResolveVariablesRecursively(ParseInfo* info) {
 }
 
 VariableProxy* Scope::FetchFreeVariables(DeclarationScope* max_outer_scope,
-                                         bool try_to_resolve, ParseInfo* info,
+                                         ParseInfo* info,
                                          VariableProxy* stack) {
   // Lazy parsed declaration scopes are already partially analyzed. If there are
   // unresolved references remaining, they just need to be resolved in outer
   // scopes.
   Scope* lookup =
-      is_declaration_scope() && AsDeclarationScope()->is_lazily_parsed()
+      is_declaration_scope() && AsDeclarationScope()->was_lazily_parsed()
           ? outer_scope()
           : this;
   for (VariableProxy *proxy = unresolved_, *next = nullptr; proxy != nullptr;
        proxy = next) {
     next = proxy->next_unresolved();
     DCHECK(!proxy->is_resolved());
-    Variable* var = nullptr;
-    if (try_to_resolve) {
-      var = lookup->LookupRecursive(proxy, max_outer_scope->outer_scope());
-    }
+    Variable* var =
+        lookup->LookupRecursive(proxy, max_outer_scope->outer_scope());
     if (var == nullptr) {
       proxy->set_next_unresolved(stack);
       stack = proxy;
-    } else if (info != nullptr) {
-      // In this case we need to leave scopes in a way that they can be
-      // allocated. If we resolved variables from lazy parsed scopes, we need to
-      // context allocate the var.
-      ResolveTo(info, proxy, var);
-      if (!var->is_dynamic() && lookup != this) var->ForceContextAllocation();
-    } else {
-      var->set_is_used();
+    } else if (var != kDummyPreParserVariable) {
+      if (info != nullptr) {
+        // In this case we need to leave scopes in a way that they can be
+        // allocated. If we resolved variables from lazy parsed scopes, we need
+        // to context allocate the var.
+        ResolveTo(info, proxy, var);
+        if (!var->is_dynamic() && lookup != this) var->ForceContextAllocation();
+      } else {
+        var->set_is_used();
+      }
     }
   }
 
@@ -1800,8 +1855,7 @@ VariableProxy* Scope::FetchFreeVariables(DeclarationScope* max_outer_scope,
   unresolved_ = nullptr;
 
   for (Scope* scope = inner_scope_; scope != nullptr; scope = scope->sibling_) {
-    stack =
-        scope->FetchFreeVariables(max_outer_scope, try_to_resolve, info, stack);
+    stack = scope->FetchFreeVariables(max_outer_scope, info, stack);
   }
 
   return stack;
@@ -1982,7 +2036,7 @@ void Scope::AllocateVariablesRecursively() {
   DCHECK(!already_resolved_);
   DCHECK_EQ(0, num_stack_slots_);
   // Don't allocate variables of preparsed scopes.
-  if (is_declaration_scope() && AsDeclarationScope()->is_lazily_parsed()) {
+  if (is_declaration_scope() && AsDeclarationScope()->was_lazily_parsed()) {
     return;
   }