[parser] Refactor of Parse*Statement*, part 5

src/parsing/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_PARSING_PARSER_H_
 #define V8_PARSING_PARSER_H_
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/parsing/parser-base.h"
@@ skipping 269 matching lines @@
   void DeclareAndInitializeVariables(
       Block* block, const DeclarationDescriptor* declaration_descriptor,
       const DeclarationParsingResult::Declaration* declaration,
       ZoneList<const AstRawString*>* names, bool* ok);
   ZoneList<const AstRawString*>* DeclareLabel(
       ZoneList<const AstRawString*>* labels, Expression* expr, bool* ok);
   bool ContainsLabel(ZoneList<const AstRawString*>* labels,
                      const AstRawString* label);
   Expression* RewriteReturn(Expression* return_value, int pos);
 
-  DoExpression* ParseDoExpression(bool* ok);
   Expression* ParseYieldStarExpression(bool* ok);
 
   class PatternRewriter final : public AstVisitor<PatternRewriter> {
    public:
     static void DeclareAndInitializeVariables(
         Parser* parser, Block* block,
         const DeclarationDescriptor* declaration_descriptor,
         const DeclarationParsingResult::Declaration* declaration,
         ZoneList<const AstRawString*>* names, bool* ok);
 
@@ skipping 66 matching lines @@
     Expression* current_value_;
     int recursion_level_;
     bool* ok_;
 
     DEFINE_AST_VISITOR_MEMBERS_WITHOUT_STACKOVERFLOW()
   };
 
   CaseClause* ParseCaseClause(bool* default_seen_ptr, bool* ok);
   Statement* ParseSwitchStatement(ZoneList<const AstRawString*>* labels,
                                   bool* ok);
-  DoWhileStatement* ParseDoWhileStatement(ZoneList<const AstRawString*>* labels,
-                                          bool* ok);
-  WhileStatement* ParseWhileStatement(ZoneList<const AstRawString*>* labels,
-                                      bool* ok);
   Statement* ParseForStatement(ZoneList<const AstRawString*>* labels, bool* ok);
-  Statement* ParseThrowStatement(bool* ok);
   Expression* MakeCatchContext(Handle<String> id, VariableProxy* value);
   TryStatement* ParseTryStatement(bool* ok);
 
   // !%_IsJSReceiver(result = iterator.next()) &&
   //     %ThrowIteratorResultNotAnObject(result)
   Expression* BuildIteratorNextResult(Expression* iterator, Variable* result,
                                       int pos);
 
   Expression* GetIterator(Expression* iterable, int pos);
 
   // Initialize the components of a for-in / for-of statement.
   Statement* InitializeForEachStatement(ForEachStatement* stmt,
                                         Expression* each, Expression* subject,
                                         Statement* body, int each_keyword_pos);
   Statement* InitializeForOfStatement(ForOfStatement* stmt, Expression* each,
                                       Expression* iterable, Statement* body,
                                       bool finalize,
                                       int next_result_pos = kNoSourcePosition);
   Statement* DesugarLexicalBindingsInForStatement(
       Scope* inner_scope, VariableMode mode,
       ZoneList<const AstRawString*>* names, ForStatement* loop, Statement* init,
       Expression* cond, Statement* next, Statement* body, bool* ok);
 
   void DesugarAsyncFunctionBody(Scope* scope, ZoneList<Statement*>* body,
                                 FunctionKind kind, FunctionBodyType type,
                                 bool accept_IN, int pos, bool* ok);
 
-  void RewriteDoExpression(Expression* expr, bool* ok);
+  Expression* RewriteDoExpression(Block* body, int pos, bool* ok);
+
+  template <typename Loop>
+  V8_INLINE Loop* InitializeLoop(Loop* loop, Expression* cond,
+                                 Statement* body) {
+    if (loop != nullptr) loop->Initialize(cond, body);

[adamk, 2016/09/08 18:44:47]

I don't understand, when can loop be null?

[nickie, 2016/09/09 09:43:37]

I don't know either, but it was in all call sites and I did not want to change
the behavior in something like this.  In the two call sites related to this CL,
the loop has just been generated by a call to a factory method.  I presume this
will never return a nullptr.  The case of the for loop is more complicated, I
haven't got there yet.

Should I add a TODO comment here?

[adamk, 2016/09/09 17:21:06]

Those if statements go back to 2009, and my reading of the code suggests that
the null check is a no-op. As for for loops, they don't even do the null check.
I'd rather not add a new method InitializeLoop as part of this refactor along
with a TODO to remove it.

Please just call Initialize() without a check.

[nickie, 2016/09/10 17:41:04]

Done.  I removed InitializeLoop and added a dummy Initialize method in
PreParserStatement.

+    return loop;
+  }
 
   FunctionLiteral* ParseFunctionLiteral(
       const AstRawString* name, Scanner::Location function_name_location,
       FunctionNameValidity function_name_validity, FunctionKind kind,
       int function_token_position, FunctionLiteral::FunctionType type,
       LanguageMode language_mode, bool* ok);
 
   Expression* ParseClassLiteral(const AstRawString* name,
                                 Scanner::Location class_name_location,
                                 bool name_is_strict_reserved, int pos,
@@ skipping 510 matching lines @@
 
   V8_INLINE Block* NewBlock(ZoneList<const AstRawString*>* labels, int capacity,
                             bool ignore_completion_value, int pos) {
     return factory()->NewBlock(labels, capacity, ignore_completion_value, pos);
   }
 
   V8_INLINE Expression* NewV8Intrinsic(const AstRawString* name,
                                        ZoneList<Expression*>* args, int pos,
                                        bool* ok);
 
+  V8_INLINE Statement* NewThrowStatement(Expression* exception, int pos) {
+    return factory()->NewExpressionStatement(
+        factory()->NewThrow(exception, pos), pos);
+  }
+
   V8_INLINE void AddParameterInitializationBlock(
       const ParserFormalParameters& parameters, ZoneList<Statement*>* body,
       bool is_async, bool* ok) {
     if (parameters.is_simple) return;
     auto* init_block = BuildParameterInitializationBlock(parameters, ok);
     if (!*ok) return;
     if (is_async) {
       init_block = BuildRejectPromiseOnException(init_block, ok);
       if (!*ok) return;
     }
@@ skipping 103 matching lines @@
 
 #ifdef DEBUG
   void Print(AstNode* node);
 #endif  // DEBUG
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSING_PARSER_H_