[destructuring] Implement parameter pattern matching.

src/parser.h

 // 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.
 
 #ifndef V8_PARSER_H_
 #define V8_PARSER_H_
 
 #include "src/allocation.h"
 #include "src/ast.h"
 #include "src/compiler.h"  // TODO(titzer): remove this include dependency
@@ skipping 520 matching lines @@
   bool is_scanned_for_captures_;
   bool failed_;
 };
 
 // ----------------------------------------------------------------------------
 // JAVASCRIPT PARSING
 
 class Parser;
 class SingletonLogger;
 
+
+struct ParserFormalParameterParsingState
+    : public PreParserFormalParameterParsingState {
+  struct Parameter {
+    Parameter(Variable* var, Expression* pattern)
+        : var(var), pattern(pattern) {}
+    Variable* var;
+    Expression* pattern;
+  };
+
+  explicit ParserFormalParameterParsingState(Scope* scope)
+      : PreParserFormalParameterParsingState(scope), params(4, scope->zone()) {}
+
+  ZoneList<Parameter> params;
+
+  void AddParameter(Variable* var, Expression* pattern) {
+    params.Add(Parameter(var, pattern), scope->zone());
+  }
+};
+
+
 class ParserTraits {
  public:
   struct Type {
     // TODO(marja): To be removed. The Traits object should contain all the data
     // it needs.
     typedef v8::internal::Parser* Parser;
 
     typedef Variable GeneratorVariable;
 
     typedef v8::internal::AstProperties AstProperties;
 
     // Return types for traversing functions.
     typedef const AstRawString* Identifier;
     typedef v8::internal::Expression* Expression;
     typedef Yield* YieldExpression;
     typedef v8::internal::FunctionLiteral* FunctionLiteral;
     typedef v8::internal::ClassLiteral* ClassLiteral;
     typedef v8::internal::Literal* Literal;
     typedef ObjectLiteral::Property* ObjectLiteralProperty;
     typedef ZoneList<v8::internal::Expression*>* ExpressionList;
     typedef ZoneList<ObjectLiteral::Property*>* PropertyList;
     typedef const v8::internal::AstRawString* FormalParameter;
-    typedef Scope FormalParameterScope;
+    typedef ParserFormalParameterParsingState FormalParameterParsingState;
     typedef ZoneList<v8::internal::Statement*>* StatementList;
 
     // For constructing objects returned by the traversing functions.
     typedef AstNodeFactory Factory;
   };
 
   explicit ParserTraits(Parser* parser) : parser_(parser) {}
 
   // Helper functions for recursive descent.
   bool IsEval(const AstRawString* identifier) const;
@@ skipping 170 matching lines @@
   Expression* GetIterator(Expression* iterable, AstNodeFactory* factory);
   ZoneList<v8::internal::Expression*>* NewExpressionList(int size, Zone* zone) {
     return new(zone) ZoneList<v8::internal::Expression*>(size, zone);
   }
   ZoneList<ObjectLiteral::Property*>* NewPropertyList(int size, Zone* zone) {
     return new(zone) ZoneList<ObjectLiteral::Property*>(size, zone);
   }
   ZoneList<v8::internal::Statement*>* NewStatementList(int size, Zone* zone) {
     return new(zone) ZoneList<v8::internal::Statement*>(size, zone);
   }
+
+  V8_INLINE void AddParameterInitializationBlock(
+      const ParserFormalParameterParsingState& formal_parameters,
+      ZoneList<v8::internal::Statement*>* body, bool* ok);
+
   V8_INLINE Scope* NewScope(Scope* parent_scope, ScopeType scope_type,
                             FunctionKind kind = kNormalFunction);
 
-  V8_INLINE void DeclareFormalParameter(Scope* scope, Expression* name,
-                                        ExpressionClassifier* classifier,
-                                        bool is_rest);
-  void ParseArrowFunctionFormalParameters(Scope* scope, Expression* params,
-                                          const Scanner::Location& params_loc,
-                                          bool* has_rest,
-                                          Scanner::Location* duplicate_loc,
-                                          bool* ok);
+  V8_INLINE void DeclareFormalParameter(
+      ParserFormalParameterParsingState* parsing_state, Expression* name,
+      ExpressionClassifier* classifier, bool is_rest);
+  void ParseArrowFunctionFormalParameters(
+      ParserFormalParameterParsingState* scope, Expression* params,
+      const Scanner::Location& params_loc, Scanner::Location* duplicate_loc,
+      bool* ok);
 
   // Temporary glue; these functions will move to ParserBase.
   Expression* ParseV8Intrinsic(bool* ok);
   FunctionLiteral* ParseFunctionLiteral(
       const AstRawString* name, Scanner::Location function_name_location,
       bool name_is_strict_reserved, FunctionKind kind,
       int function_token_position, FunctionLiteral::FunctionType type,
       FunctionLiteral::ArityRestriction arity_restriction, bool* ok);
   V8_INLINE void SkipLazyFunctionBody(
       int* materialized_literal_count, int* expected_property_count, bool* ok,
       Scanner::BookmarkScope* bookmark = nullptr);
   V8_INLINE ZoneList<Statement*>* ParseEagerFunctionBody(
-      const AstRawString* name, int pos, Variable* fvar,
-      Token::Value fvar_init_op, FunctionKind kind, bool* ok);
+      const AstRawString* name, int pos,
+      const ParserFormalParameterParsingState& formal_parameters,
+      Variable* fvar, Token::Value fvar_init_op, FunctionKind kind, bool* ok);
 
   ClassLiteral* ParseClassLiteral(const AstRawString* name,
                                   Scanner::Location class_name_location,
                                   bool name_is_strict_reserved, int pos,
                                   bool* ok);
 
   V8_INLINE void CheckConflictingVarDeclarations(v8::internal::Scope* scope,
                                                  bool* ok);
 
   class TemplateLiteral : public ZoneObject {
@@ skipping 140 matching lines @@
                                       bool* ok);
   Statement* ParseClassDeclaration(ZoneList<const AstRawString*>* names,
                                    bool* ok);
   Statement* ParseNativeDeclaration(bool* ok);
   Block* ParseBlock(ZoneList<const AstRawString*>* labels, bool* ok);
   Block* ParseVariableStatement(VariableDeclarationContext var_context,
                                 ZoneList<const AstRawString*>* names,
                                 bool* ok);
 
   struct DeclarationDescriptor {
+    enum Kind { NORMAL, PARAMETER };
     Parser* parser;
     Scope* declaration_scope;
     Scope* scope;
     VariableMode mode;
     bool is_const;
     bool needs_init;
     int declaration_pos;
     int initialization_pos;
     Token::Value init_op;
+    Kind declaration_kind;
   };
 
   struct DeclarationParsingResult {
     struct Declaration {
       Declaration(Expression* pattern, int initializer_position,
                   Expression* initializer)
           : pattern(pattern),
             initializer_position(initializer_position),
             initializer(initializer) {}
 
@@ skipping 130 matching lines @@
   // function f() { { { var x; } let x; } }
   // function g() { { var x; let x; } }
   //
   // The var declarations are hoisted to the function scope, but originate from
   // a scope where the name has also been let bound or the var declaration is
   // hoisted over such a scope.
   void CheckConflictingVarDeclarations(Scope* scope, bool* ok);
 
   // Parser support
   VariableProxy* NewUnresolved(const AstRawString* name, VariableMode mode);
-  Variable* Declare(Declaration* declaration, bool resolve, bool* ok);
+  Variable* Declare(Declaration* declaration,
+                    DeclarationDescriptor::Kind declaration_kind, bool resolve,
+                    bool* ok);
 
   bool TargetStackContainsLabel(const AstRawString* label);
   BreakableStatement* LookupBreakTarget(const AstRawString* label, bool* ok);
   IterationStatement* LookupContinueTarget(const AstRawString* label, bool* ok);
 
   void AddAssertIsConstruct(ZoneList<Statement*>* body, int pos);
   Statement* BuildAssertIsCoercible(Variable* var);
 
   // Factory methods.
   FunctionLiteral* DefaultConstructor(bool call_super, Scope* scope, int pos,
                                       int end_pos);
 
   // Skip over a lazy function, either using cached data if we have it, or
   // by parsing the function with PreParser. Consumes the ending }.
   //
   // If bookmark is set, the (pre-)parser may decide to abort skipping
   // in order to force the function to be eagerly parsed, after all.
   // In this case, it'll reset the scanner using the bookmark.
   void SkipLazyFunctionBody(int* materialized_literal_count,
                             int* expected_property_count, bool* ok,
                             Scanner::BookmarkScope* bookmark = nullptr);
 
   PreParser::PreParseResult ParseLazyFunctionBodyWithPreParser(
       SingletonLogger* logger, Scanner::BookmarkScope* bookmark = nullptr);
 
+  Block* BuildParameterInitializationBlock(
+      const ParserFormalParameterParsingState& formal_parameters, bool* ok);
+
   // Consumes the ending }.
   ZoneList<Statement*>* ParseEagerFunctionBody(
-      const AstRawString* function_name, int pos, Variable* fvar,
-      Token::Value fvar_init_op, FunctionKind kind, bool* ok);
+      const AstRawString* function_name, int pos,
+      const ParserFormalParameterParsingState& formal_parameters,
+      Variable* fvar, Token::Value fvar_init_op, FunctionKind kind, bool* ok);
 
   void ThrowPendingError(Isolate* isolate, Handle<Script> script);
 
   TemplateLiteralState OpenTemplateLiteral(int pos);
   void AddTemplateSpan(TemplateLiteralState* state, bool tail);
   void AddTemplateExpression(TemplateLiteralState* state,
                              Expression* expression);
   Expression* CloseTemplateLiteral(TemplateLiteralState* state, int start,
                                    Expression* tag);
   uint32_t ComputeTemplateLiteralHash(const TemplateLiteral* lit);
@@ skipping 43 matching lines @@
 
 void ParserTraits::SkipLazyFunctionBody(int* materialized_literal_count,
                                         int* expected_property_count, bool* ok,
                                         Scanner::BookmarkScope* bookmark) {
   return parser_->SkipLazyFunctionBody(materialized_literal_count,
                                        expected_property_count, ok, bookmark);
 }
 
 
 ZoneList<Statement*>* ParserTraits::ParseEagerFunctionBody(
-    const AstRawString* name, int pos, Variable* fvar,
+    const AstRawString* name, int pos,
+    const ParserFormalParameterParsingState& formal_parameters, Variable* fvar,
     Token::Value fvar_init_op, FunctionKind kind, bool* ok) {
-  return parser_->ParseEagerFunctionBody(name, pos, fvar, fvar_init_op, kind,
-                                         ok);
+  return parser_->ParseEagerFunctionBody(name, pos, formal_parameters, fvar,
+                                         fvar_init_op, kind, ok);
 }
 
 void ParserTraits::CheckConflictingVarDeclarations(v8::internal::Scope* scope,
                                                    bool* ok) {
   parser_->CheckConflictingVarDeclarations(scope, ok);
 }
 
 
 // Support for handling complex values (array and object literals) that
 // can be fully handled at compile time.
@@ skipping 58 matching lines @@
   return parser_->SpreadCall(function, args, pos);
 }
 
 
 Expression* ParserTraits::SpreadCallNew(
     Expression* function, ZoneList<v8::internal::Expression*>* args, int pos) {
   return parser_->SpreadCallNew(function, args, pos);
 }
 
 
-void ParserTraits::DeclareFormalParameter(Scope* scope, Expression* pattern,
-                                          ExpressionClassifier* classifier,
-                                          bool is_rest) {
+void ParserTraits::DeclareFormalParameter(
+    ParserFormalParameterParsingState* parsing_state, Expression* pattern,
+    ExpressionClassifier* classifier, bool is_rest) {
   bool is_duplicate = false;
-  if (!pattern->IsVariableProxy()) {
-    // TODO(dslomov): implement.
-    DCHECK(parser_->allow_harmony_destructuring());
-    return;
-  }
-  auto name = pattern->AsVariableProxy()->raw_name();
-  Variable* var = scope->DeclareParameter(name, VAR, is_rest, &is_duplicate);
-  if (is_sloppy(scope->language_mode())) {
+  bool is_simple_name = pattern->IsVariableProxy();
+  DCHECK(parser_->allow_harmony_destructuring() || is_simple_name);
+
+  const AstRawString* name = is_simple_name
+                                 ? pattern->AsVariableProxy()->raw_name()
+                                 : parser_->ast_value_factory()->empty_string();
+  Variable* var =
+      parsing_state->scope->DeclareParameter(name, VAR, is_rest, &is_duplicate);
+  parsing_state->AddParameter(var, is_simple_name ? nullptr : pattern);
+  if (is_sloppy(parsing_state->scope->language_mode())) {
     // TODO(sigurds) Mark every parameter as maybe assigned. This is a
     // conservative approximation necessary to account for parameters
     // that are assigned via the arguments array.
     var->set_maybe_assigned();
   }
   if (is_duplicate) {
     classifier->RecordDuplicateFormalParameterError(
         parser_->scanner()->location());
   }
 }
+
+
+void ParserTraits::AddParameterInitializationBlock(
+    const ParserFormalParameterParsingState& formal_parameters,
+    ZoneList<v8::internal::Statement*>* body, bool* ok) {
+  auto* init_block =
+      parser_->BuildParameterInitializationBlock(formal_parameters, ok);
+  if (!*ok) return;
+  if (init_block != nullptr) {
+    body->Add(init_block, parser_->zone());
+  }
+}
 } }  // namespace v8::internal
 
 #endif  // V8_PARSER_H_