[destructuring] Implement parameter pattern matching.

src/parser.h

Index: src/parser.h
diff --git a/src/parser.h b/src/parser.h
index 39d0d9278b132fd4dfc5a9ebd104661f1f846205..103bafea3341595f4d08ef58d425567ce037da99 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -538,6 +538,27 @@ class RegExpParser BASE_EMBEDDED {
 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 {
@@ -560,7 +581,7 @@ class ParserTraits {
     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.
@@ -751,17 +772,21 @@ class ParserTraits {
   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);
@@ -774,8 +799,9 @@ class ParserTraits {
       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,
@@ -936,6 +962,7 @@ class Parser : public ParserBase<ParserTraits> {
                                 bool* ok);
 
   struct DeclarationDescriptor {
+    enum Kind { NORMAL, PARAMETER };
     Parser* parser;
     Scope* declaration_scope;
     Scope* scope;
@@ -945,6 +972,7 @@ class Parser : public ParserBase<ParserTraits> {
     int declaration_pos;
     int initialization_pos;
     Token::Value init_op;
+    Kind declaration_kind;
   };
 
   struct DeclarationParsingResult {
@@ -1095,7 +1123,9 @@ class Parser : public ParserBase<ParserTraits> {
 
   // 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);
@@ -1121,10 +1151,14 @@ class Parser : public ParserBase<ParserTraits> {
   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);
 
@@ -1188,10 +1222,11 @@ void ParserTraits::SkipLazyFunctionBody(int* materialized_literal_count,
 
 
 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,
@@ -1270,18 +1305,20 @@ Expression* ParserTraits::SpreadCallNew(
 }
 
 
-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.
@@ -1292,6 +1329,18 @@ void ParserTraits::DeclareFormalParameter(Scope* scope, Expression* pattern,
         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_