Remove Scope::scope_uses_arguments_ flag

Use of arguments is tracked as a variable, like any other variable.

R=arv@chromium.org
LOG=N
BUG=

Review URL: https://codereview.chromium.org/1124233002

Cr-Commit-Position: refs/heads/master@{#28271}

src/preparser.h

@@ -2076,7 +2076,6 @@ ParserBase<Traits>::ParseAndClassifyIdentifier(ExpressionClassifier* classifier,
       classifier->RecordExpressionError(scanner()->location(),
                                         "strong_arguments");
     }
-    if (this->IsArguments(name)) scope_->RecordArgumentsUsage();
     return name;
   } else if (is_sloppy(language_mode()) &&
              (next == Token::FUTURE_STRICT_RESERVED_WORD ||
@@ -2109,7 +2108,6 @@ typename ParserBase<Traits>::IdentifierT ParserBase<
   }
 
   IdentifierT name = this->GetSymbol(scanner());
-  if (this->IsArguments(name)) scope_->RecordArgumentsUsage();
   return name;
 }
 
@@ -2127,7 +2125,6 @@ ParserBase<Traits>::ParseIdentifierName(bool* ok) {
   }
 
   IdentifierT name = this->GetSymbol(scanner());
-  if (this->IsArguments(name)) scope_->RecordArgumentsUsage();
   return name;
 }
 

src/scopes.cc

@@ -163,7 +163,6 @@ void Scope::SetDefaults(ScopeType scope_type, Scope* outer_scope,
   scope_inside_with_ = false;
   scope_contains_with_ = false;
   scope_calls_eval_ = false;
-  scope_uses_arguments_ = false;
   scope_uses_super_property_ = false;
   asm_module_ = false;
   asm_function_ = outer_scope != NULL && outer_scope->asm_module_;
@@ -171,7 +170,6 @@ void Scope::SetDefaults(ScopeType scope_type, Scope* outer_scope,
   language_mode_ = outer_scope != NULL ? outer_scope->language_mode_ : SLOPPY;
   outer_scope_calls_sloppy_eval_ = false;
   inner_scope_calls_eval_ = false;
-  inner_scope_uses_arguments_ = false;
   inner_scope_uses_super_property_ = false;
   force_eager_compilation_ = false;
   force_context_allocation_ = (outer_scope != NULL && !is_function_scope())
@@ -367,7 +365,6 @@ Scope* Scope::FinalizeBlockScope() {
   }
 
   // Propagate usage flags to outer scope.
-  if (uses_arguments()) outer_scope_->RecordArgumentsUsage();
   if (uses_super_property()) outer_scope_->RecordSuperPropertyUsage();
   if (scope_calls_eval_) outer_scope_->RecordEvalCall();
 
@@ -915,12 +912,8 @@ void Scope::Print(int n) {
   if (scope_inside_with_) Indent(n1, "// scope inside 'with'\n");
   if (scope_contains_with_) Indent(n1, "// scope contains 'with'\n");
   if (scope_calls_eval_) Indent(n1, "// scope calls 'eval'\n");
-  if (scope_uses_arguments_) Indent(n1, "// scope uses 'arguments'\n");
   if (scope_uses_super_property_)
     Indent(n1, "// scope uses 'super' property\n");
-  if (inner_scope_uses_arguments_) {
-    Indent(n1, "// inner scope uses 'arguments'\n");
-  }
   if (inner_scope_uses_super_property_)
     Indent(n1, "// inner scope uses 'super' property\n");
   if (outer_scope_calls_sloppy_eval_) {
@@ -1271,9 +1264,6 @@ void Scope::PropagateScopeInfo(bool outer_scope_calls_sloppy_eval ) {
     // usage of arguments/super/this, but do not propagate them out from normal
     // functions.
     if (!inner->is_function_scope() || inner->is_arrow_scope()) {
-      if (inner->scope_uses_arguments_ || inner->inner_scope_uses_arguments_) {
-        inner_scope_uses_arguments_ = true;
-      }
       if (inner->scope_uses_super_property_ ||
           inner->inner_scope_uses_super_property_) {
         inner_scope_uses_super_property_ = true;

src/scopes.h

@@ -212,9 +212,6 @@ class Scope: public ZoneObject {
   // Inform the scope that the corresponding code contains an eval call.
   void RecordEvalCall() { if (!is_script_scope()) scope_calls_eval_ = true; }
 
-  // Inform the scope that the corresponding code uses "arguments".
-  void RecordArgumentsUsage() { scope_uses_arguments_ = true; }
-
   // Inform the scope that the corresponding code uses "super".
   void RecordSuperPropertyUsage() { scope_uses_super_property_ = true; }
 
@@ -311,10 +308,6 @@ class Scope: public ZoneObject {
   // Does this scope contain a with statement.
   bool contains_with() const { return scope_contains_with_; }
 
-  // Does this scope access "arguments".
-  bool uses_arguments() const { return scope_uses_arguments_; }
-  // Does any inner scope access "arguments".
-  bool inner_uses_arguments() const { return inner_scope_uses_arguments_; }
   // Does this scope access "super" property (super.foo).
   bool uses_super_property() const { return scope_uses_super_property_; }
   // Does any inner scope access "super" property.
@@ -581,8 +574,6 @@ class Scope: public ZoneObject {
   // This scope or a nested catch scope or with scope contain an 'eval' call. At
   // the 'eval' call site this scope is the declaration scope.
   bool scope_calls_eval_;
-  // This scope uses "arguments".
-  bool scope_uses_arguments_;
   // This scope uses "super" property ('super.foo').
   bool scope_uses_super_property_;
   // This scope contains an "use asm" annotation.
@@ -598,7 +589,6 @@ class Scope: public ZoneObject {
   // Computed via PropagateScopeInfo.
   bool outer_scope_calls_sloppy_eval_;
   bool inner_scope_calls_eval_;
-  bool inner_scope_uses_arguments_;
   bool inner_scope_uses_super_property_;
   bool force_eager_compilation_;
   bool force_context_allocation_;

test/cctest/test-parsing.cc

@@ -960,7 +960,6 @@ TEST(ScopeUsesArgumentsSuperThis) {
     ARGUMENTS = 1,
     SUPER_PROPERTY = 1 << 1,
     THIS = 1 << 2,
-    INNER_ARGUMENTS = 1 << 3,
     INNER_SUPER_PROPERTY = 1 << 4,
   };
 
@@ -1001,9 +1000,9 @@ TEST(ScopeUsesArgumentsSuperThis) {
     {"return { m(x) { return () => super.m() } }", NONE},
     // Flags must be correctly set when using block scoping.
     {"\"use strict\"; while (true) { let x; this, arguments; }",
-     INNER_ARGUMENTS | THIS},
+     ARGUMENTS | THIS},
     {"\"use strict\"; while (true) { let x; this, super.f(), arguments; }",
-     INNER_ARGUMENTS | INNER_SUPER_PROPERTY | THIS},
+     ARGUMENTS | INNER_SUPER_PROPERTY | THIS},
     {"\"use strict\"; if (foo()) { let x; this.f() }", THIS},
     {"\"use strict\"; if (foo()) { let x; super.f() }",
      INNER_SUPER_PROPERTY},
@@ -1064,8 +1063,10 @@ TEST(ScopeUsesArgumentsSuperThis) {
         CHECK_EQ(1, scope->inner_scopes()->length());
         scope = scope->inner_scopes()->at(0);
       }
-      CHECK_EQ((source_data[i].expected & ARGUMENTS) != 0,
-               scope->uses_arguments());
+      // Arguments usage in an arrow function doesn't cause local allocation of
+      // an arguments object.
+      CHECK_EQ((source_data[i].expected & ARGUMENTS) != 0 && j != 1,
+               scope->arguments() != nullptr);
       CHECK_EQ((source_data[i].expected & SUPER_PROPERTY) != 0,
                scope->uses_super_property());
       if ((source_data[i].expected & THIS) != 0) {
@@ -1073,8 +1074,6 @@ TEST(ScopeUsesArgumentsSuperThis) {
         // script scope are marked as used.
         CHECK(scope->LookupThis()->is_used());
       }
-      CHECK_EQ((source_data[i].expected & INNER_ARGUMENTS) != 0,
-               scope->inner_uses_arguments());
       CHECK_EQ((source_data[i].expected & INNER_SUPER_PROPERTY) != 0,
                scope->inner_uses_super_property());
     }