PreParser: track variable declarations and parameters

src/ast/scopes.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/ast/scopes.h"
 
 #include <set>
 
 #include "src/accessors.h"
 #include "src/ast/ast.h"
 #include "src/bootstrapper.h"
 #include "src/messages.h"
 #include "src/parsing/parse-info.h"
 
 namespace v8 {
 namespace internal {
 
+namespace {
+void* kDummyPreParserVariable = reinterpret_cast<void*>(0x1);
+}  // namespace
+
 // ----------------------------------------------------------------------------
 // Implementation of LocalsMap
 //
 // Note: We are storing the handle locations as key values in the hash map.
 //       When inserting a new variable via Declare(), we rely on the fact that
 //       the handle location remains alive for the duration of that variable
 //       use. Because a Variable holding a handle with the same location exists
 //       this is ensured.
 
 VariableMap::VariableMap(Zone* zone)
@@ skipping 14 matching lines @@
   if (added) *added = p->value == nullptr;
   if (p->value == nullptr) {
     // The variable has not been declared yet -> insert it.
     DCHECK_EQ(name, p->key);
     p->value = new (zone) Variable(scope, name, mode, kind, initialization_flag,
                                    maybe_assigned_flag);
   }
   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());
 }
 
 void VariableMap::Add(Zone* zone, Variable* var) {
   const AstRawString* name = var->raw_name();
   Entry* p =
       ZoneHashMap::LookupOrInsert(const_cast<AstRawString*>(name), name->hash(),
                                   ZoneAllocationPolicy(zone));
@@ skipping 194 matching lines @@
   force_eager_compilation_ = false;
   has_arguments_parameter_ = false;
   scope_uses_super_property_ = false;
   has_rest_ = false;
   receiver_ = nullptr;
   new_target_ = nullptr;
   function_ = nullptr;
   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() {
 #ifdef DEBUG
   scope_name_ = nullptr;
   already_resolved_ = false;
   needs_migration_ = false;
 #endif
   inner_scope_ = nullptr;
   sibling_ = nullptr;
@@ skipping 21 matching lines @@
 bool Scope::HasSimpleParameters() {
   DeclarationScope* scope = GetClosureScope();
   return !scope->is_function_scope() || scope->has_simple_parameters();
 }
 
 bool DeclarationScope::ShouldEagerCompile() const {
   return force_eager_compilation_ || should_eager_compile_;
 }
 
 void DeclarationScope::set_should_eager_compile() {
-  should_eager_compile_ = !is_lazily_parsed_;
+  should_eager_compile_ = !was_lazily_parsed_;
 }
 
 void DeclarationScope::set_asm_module() {
   asm_module_ = true;
   // Mark any existing inner function scopes as asm function scopes.
   for (Scope* inner = inner_scope_; inner != nullptr; inner = inner->sibling_) {
     if (inner->is_function_scope()) {
       inner->AsDeclarationScope()->set_asm_function();
     }
   }
@@ skipping 540 matching lines @@
   return NULL;
 }
 
 Variable* DeclarationScope::DeclareParameter(
     const AstRawString* name, VariableMode mode, bool is_optional, bool is_rest,
     bool* is_duplicate, AstValueFactory* ast_value_factory) {
   DCHECK(!already_resolved_);
   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);
   } else {
     var = Declare(zone(), name, mode, NORMAL_VARIABLE, kCreatedInitialized);
     // TODO(wingo): Avoid O(n^2) check.
     *is_duplicate = IsDeclaredParameter(name);
   }
   has_rest_ = is_rest;
   params_.Add(var, zone());
   if (name == ast_value_factory->arguments_string()) {
     has_arguments_parameter_ = true;
   }
   return var;
 }
 
 Variable* Scope::DeclareLocal(const AstRawString* name, VariableMode mode,
                               InitializationFlag init_flag, VariableKind kind,
                               MaybeAssignedFlag maybe_assigned_flag) {
   DCHECK(!already_resolved_);
   // This function handles VAR, LET, and CONST modes.  DYNAMIC variables are
   // 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);
 }
 
 Variable* Scope::DeclareVariable(
     Declaration* declaration, VariableMode mode, InitializationFlag init,
     bool allow_harmony_restrictive_generators,
     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(
         declaration, mode, init, allow_harmony_restrictive_generators,
         sloppy_mode_block_scope_function_redefinition, ok);
   }
   DCHECK(!is_catch_scope());
   DCHECK(!is_with_scope());
   DCHECK(is_declaration_scope() ||
          (IsLexicalVariableMode(mode) && is_block_scope()));
@@ skipping 78 matching lines @@
   //
   // This will lead to multiple declaration nodes for the
   // same variable if it is declared several times. This is not a
   // semantic issue, but it may be a performance issue since it may
   // lead to repeated DeclareEvalVar or DeclareEvalFunction calls.
   decls_.Add(declaration);
   proxy->BindTo(var);
   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) {
   // Note that we must not share the unresolved variables with
   // the same name because they may be removed selectively via
   // RemoveUnresolved().
   DCHECK(!already_resolved_);
   DCHECK_EQ(factory->zone(), zone());
   VariableProxy* proxy = factory->NewVariableProxy(name, kind, start_position);
   proxy->set_next_unresolved(unresolved_);
@@ skipping 254 matching lines @@
 Scope* Scope::GetOuterScopeWithContext() {
   Scope* scope = outer_scope_;
   while (scope && !scope->NeedsContext()) {
     scope = scope->outer_scope();
   }
   return scope;
 }
 
 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());
   }
   return non_locals;
 }
 
 void DeclarationScope::ResetAfterPreparsing(AstValueFactory* ast_value_factory,
                                             bool aborted) {
   DCHECK(is_function_scope());
@@ skipping 15 matching lines @@
     }
   } else {
     // Make sure this scope isn't used for allocation anymore.
     zone_ = nullptr;
     variables_.Invalidate();
     sloppy_block_function_map_.Invalidate();
   }
 
 #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) {
   DCHECK(!force_eager_compilation_);
   VariableProxy* unresolved = nullptr;
 
   if (!outer_scope_->is_script_scope()) {
     // 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);
       unresolved = copy;
     }
 
     // Clear arguments_ if unused. This is used as a signal for optimization.
     if (arguments_ != nullptr &&
         !(MustAllocate(arguments_) && !has_arguments_parameter_)) {
       arguments_ = nullptr;
@@ skipping 147 matching lines @@
   }
   if (IsAsmModule()) Indent(n1, "// scope is an asm module\n");
   if (IsAsmFunction()) Indent(n1, "// scope is an asm function\n");
   if (scope_calls_eval_) Indent(n1, "// scope calls 'eval'\n");
   if (is_declaration_scope() && AsDeclarationScope()->uses_super_property()) {
     Indent(n1, "// scope uses 'super' property\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) {
     Indent(n1, "// ");
     PrintF("%d stack slots\n", num_stack_slots_);
   }
   if (num_heap_slots_ > 0) {
     Indent(n1, "// ");
     PrintF("%d heap slots\n", num_heap_slots_);
   }
@@ skipping 32 matching lines @@
   }
   for (Scope* scope = inner_scope_; scope != nullptr; scope = scope->sibling_) {
     scope->CheckScopePositions();
   }
 }
 
 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;
     }
     CHECK_EQ(scope->zone(), zone());
     scope->CheckZones();
   }
 }
 #endif  // DEBUG
 
@@ skipping 35 matching lines @@
                                                       NORMAL_VARIABLE);
   }
 
   DCHECK(!is_script_scope());
 
   var = outer_scope_->LookupRecursive(proxy, 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();
   }
   // "this" can't be shadowed by "eval"-introduced bindings or by "with"
   // scopes.
   // TODO(wingo): There are other variables in this category; add them.
   if (var->is_this()) return var;
 
   if (is_with_scope()) {
     // The current scope is a with scope, so the variable binding can not be
@@ skipping 119 matching lines @@
   if (proxy->is_assigned()) var->set_maybe_assigned();
   if (AccessNeedsHoleCheck(var, proxy, this)) proxy->set_needs_hole_check();
   proxy->BindTo(var);
 }
 
 void Scope::ResolveVariablesRecursively(ParseInfo* info) {
   DCHECK(info->script_scope()->is_script_scope());
   // 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()) {
       Variable* var = outer_scope()->LookupRecursive(proxy, nullptr);
       if (!var->is_dynamic()) {
         var->set_is_used();
         var->ForceContextAllocation();
         if (proxy->is_assigned()) var->set_maybe_assigned();
       }
     }
   } else {
     // Resolve unresolved variables for this scope.
     for (VariableProxy* proxy = unresolved_; proxy != nullptr;
          proxy = proxy->next_unresolved()) {
       ResolveVariable(info, proxy);
     }
 
     // Resolve unresolved variables for inner scopes.
     for (Scope* scope = inner_scope_; scope != nullptr;
          scope = scope->sibling_) {
       scope->ResolveVariablesRecursively(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();
+      }
     }
   }
 
   // Clear unresolved_ as it's in an inconsistent state.
   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;
 }
 
 bool Scope::MustAllocate(Variable* var) {
   DCHECK(var->location() != VariableLocation::MODULE);
   // Give var a read/write use if there is a chance it might be accessed
   // via an eval() call.  This is only possible if the variable has a
   // visible name.
@@ skipping 160 matching lines @@
     Variable* var = LookupLocal(it.first);
     var->AllocateTo(VariableLocation::MODULE, it.second->cell_index);
     DCHECK(var->IsExport());
   }
 }
 
 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;
   }
 
   // Allocate variables for inner scopes.
   for (Scope* scope = inner_scope_; scope != nullptr; scope = scope->sibling_) {
     scope->AllocateVariablesRecursively();
   }
 
   DCHECK(!already_resolved_);
   DCHECK_EQ(Context::MIN_CONTEXT_SLOTS, num_heap_slots_);
@@ skipping 73 matching lines @@
   Variable* function =
       is_function_scope() ? AsDeclarationScope()->function_var() : nullptr;
   bool is_function_var_in_context =
       function != nullptr && function->IsContextSlot();
   return num_heap_slots() - Context::MIN_CONTEXT_SLOTS -
          (is_function_var_in_context ? 1 : 0);
 }
 
 }  // namespace internal
 }  // namespace v8