Create ast/ and parsing/ subdirectories and move appropriate files

src/rewriter.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/rewriter.h"
-
-#include "src/ast.h"
-#include "src/parser.h"
-#include "src/scopes.h"
-
-namespace v8 {
-namespace internal {
-
-class Processor: public AstVisitor {
- public:
-  Processor(Isolate* isolate, Scope* scope, Variable* result,
-            AstValueFactory* ast_value_factory)
-      : result_(result),
-        result_assigned_(false),
-        replacement_(nullptr),
-        is_set_(false),
-        zone_(ast_value_factory->zone()),
-        scope_(scope),
-        factory_(ast_value_factory) {
-    InitializeAstVisitor(isolate);
-  }
-
-  Processor(Parser* parser, Scope* scope, Variable* result,
-            AstValueFactory* ast_value_factory)
-      : result_(result),
-        result_assigned_(false),
-        replacement_(nullptr),
-        is_set_(false),
-        scope_(scope),
-        factory_(ast_value_factory) {
-    InitializeAstVisitor(parser->stack_limit());
-  }
-
-  ~Processor() override {}
-
-  void Process(ZoneList<Statement*>* statements);
-  bool result_assigned() const { return result_assigned_; }
-
-  Zone* zone() { return zone_; }
-  Scope* scope() { return scope_; }
-  AstNodeFactory* factory() { return &factory_; }
-
-  // Returns ".result = value"
-  Expression* SetResult(Expression* value) {
-    result_assigned_ = true;
-    VariableProxy* result_proxy = factory()->NewVariableProxy(result_);
-    return factory()->NewAssignment(Token::ASSIGN, result_proxy, value,
-                                    RelocInfo::kNoPosition);
-  }
-
-  // Inserts '.result = undefined' in front of the given statement.
-  Statement* AssignUndefinedBefore(Statement* s);
-
- private:
-  Variable* result_;
-
-  // We are not tracking result usage via the result_'s use
-  // counts (we leave the accurate computation to the
-  // usage analyzer). Instead we simple remember if
-  // there was ever an assignment to result_.
-  bool result_assigned_;
-
-  // When visiting a node, we "return" a replacement for that node in
-  // [replacement_].  In many cases this will just be the original node.
-  Statement* replacement_;
-
-  // To avoid storing to .result all the time, we eliminate some of
-  // the stores by keeping track of whether or not we're sure .result
-  // will be overwritten anyway. This is a bit more tricky than what I
-  // was hoping for.
-  bool is_set_;
-
-  Zone* zone_;
-  Scope* scope_;
-  AstNodeFactory factory_;
-
-  // Node visitors.
-#define DEF_VISIT(type) void Visit##type(type* node) override;
-  AST_NODE_LIST(DEF_VISIT)
-#undef DEF_VISIT
-
-  void VisitIterationStatement(IterationStatement* stmt);
-
-  DEFINE_AST_VISITOR_SUBCLASS_MEMBERS();
-};
-
-
-Statement* Processor::AssignUndefinedBefore(Statement* s) {
-  Expression* result_proxy = factory()->NewVariableProxy(result_);
-  Expression* undef = factory()->NewUndefinedLiteral(RelocInfo::kNoPosition);
-  Expression* assignment = factory()->NewAssignment(
-      Token::ASSIGN, result_proxy, undef, RelocInfo::kNoPosition);
-  Block* b = factory()->NewBlock(NULL, 2, false, RelocInfo::kNoPosition);
-  b->statements()->Add(
-      factory()->NewExpressionStatement(assignment, RelocInfo::kNoPosition),
-      zone());
-  b->statements()->Add(s, zone());
-  return b;
-}
-
-
-void Processor::Process(ZoneList<Statement*>* statements) {
-  for (int i = statements->length() - 1; i >= 0; --i) {
-    Visit(statements->at(i));
-    statements->Set(i, replacement_);
-  }
-}
-
-
-void Processor::VisitBlock(Block* node) {
-  // An initializer block is the rewritten form of a variable declaration
-  // with initialization expressions. The initializer block contains the
-  // list of assignments corresponding to the initialization expressions.
-  // While unclear from the spec (ECMA-262, 3rd., 12.2), the value of
-  // a variable declaration with initialization expression is 'undefined'
-  // with some JS VMs: For instance, using smjs, print(eval('var x = 7'))
-  // returns 'undefined'. To obtain the same behavior with v8, we need
-  // to prevent rewriting in that case.
-  if (!node->ignore_completion_value()) Process(node->statements());
-  replacement_ = node;
-}
-
-
-void Processor::VisitExpressionStatement(ExpressionStatement* node) {
-  // Rewrite : <x>; -> .result = <x>;
-  if (!is_set_) {
-    node->set_expression(SetResult(node->expression()));
-    is_set_ = true;
-  }
-  replacement_ = node;
-}
-
-
-void Processor::VisitIfStatement(IfStatement* node) {
-  // Rewrite both branches.
-  bool set_after = is_set_;
-  Visit(node->then_statement());
-  node->set_then_statement(replacement_);
-  bool set_in_then = is_set_;
-  is_set_ = set_after;
-  Visit(node->else_statement());
-  node->set_else_statement(replacement_);
-  is_set_ = is_set_ && set_in_then;
-  replacement_ = node;
-
-  if (FLAG_harmony_completion && !is_set_) {
-    is_set_ = true;
-    replacement_ = AssignUndefinedBefore(node);
-  }
-}
-
-
-void Processor::VisitIterationStatement(IterationStatement* node) {
-  // Rewrite the body.
-  bool set_after = is_set_;
-  is_set_ = false;  // We are in a loop, so we can't rely on [set_after].
-  Visit(node->body());
-  node->set_body(replacement_);
-  is_set_ = is_set_ && set_after;
-  replacement_ = node;
-
-  if (FLAG_harmony_completion && !is_set_) {
-    is_set_ = true;
-    replacement_ = AssignUndefinedBefore(node);
-  }
-}
-
-
-void Processor::VisitDoWhileStatement(DoWhileStatement* node) {
-  VisitIterationStatement(node);
-}
-
-
-void Processor::VisitWhileStatement(WhileStatement* node) {
-  VisitIterationStatement(node);
-}
-
-
-void Processor::VisitForStatement(ForStatement* node) {
-  VisitIterationStatement(node);
-}
-
-
-void Processor::VisitForInStatement(ForInStatement* node) {
-  VisitIterationStatement(node);
-}
-
-
-void Processor::VisitForOfStatement(ForOfStatement* node) {
-  VisitIterationStatement(node);
-}
-
-
-void Processor::VisitTryCatchStatement(TryCatchStatement* node) {
-  // Rewrite both try and catch block.
-  bool set_after = is_set_;
-  Visit(node->try_block());
-  node->set_try_block(static_cast<Block*>(replacement_));
-  bool set_in_try = is_set_;
-  is_set_ = set_after;
-  Visit(node->catch_block());
-  node->set_catch_block(static_cast<Block*>(replacement_));
-  is_set_ = is_set_ && set_in_try;
-  replacement_ = node;
-
-  if (FLAG_harmony_completion && !is_set_) {
-    is_set_ = true;
-    replacement_ = AssignUndefinedBefore(node);
-  }
-}
-
-
-void Processor::VisitTryFinallyStatement(TryFinallyStatement* node) {
-  // Rewrite both try and finally block (in reverse order).
-  bool set_after = is_set_;
-  is_set_ = true;  // Don't normally need to assign in finally block.
-  Visit(node->finally_block());
-  node->set_finally_block(replacement_->AsBlock());
-  {  // Save .result value at the beginning of the finally block and restore it
-     // at the end again: ".backup = .result; ...; .result = .backup"
-     // This is necessary because the finally block does not normally contribute
-     // to the completion value.
-    Variable* backup = scope()->NewTemporary(
-        factory()->ast_value_factory()->dot_result_string());
-    Expression* backup_proxy = factory()->NewVariableProxy(backup);
-    Expression* result_proxy = factory()->NewVariableProxy(result_);
-    Expression* save = factory()->NewAssignment(
-        Token::ASSIGN, backup_proxy, result_proxy, RelocInfo::kNoPosition);
-    Expression* restore = factory()->NewAssignment(
-        Token::ASSIGN, result_proxy, backup_proxy, RelocInfo::kNoPosition);
-    node->finally_block()->statements()->InsertAt(
-        0, factory()->NewExpressionStatement(save, RelocInfo::kNoPosition),
-        zone());
-    node->finally_block()->statements()->Add(
-        factory()->NewExpressionStatement(restore, RelocInfo::kNoPosition),
-        zone());
-  }
-  is_set_ = set_after;
-  Visit(node->try_block());
-  node->set_try_block(replacement_->AsBlock());
-  replacement_ = node;
-
-  if (FLAG_harmony_completion && !is_set_) {
-    is_set_ = true;
-    replacement_ = AssignUndefinedBefore(node);
-  }
-}
-
-
-void Processor::VisitSwitchStatement(SwitchStatement* node) {
-  // Rewrite statements in all case clauses (in reverse order).
-  ZoneList<CaseClause*>* clauses = node->cases();
-  bool set_after = is_set_;
-  for (int i = clauses->length() - 1; i >= 0; --i) {
-    CaseClause* clause = clauses->at(i);
-    Process(clause->statements());
-  }
-  is_set_ = is_set_ && set_after;
-  replacement_ = node;
-
-  if (FLAG_harmony_completion && !is_set_) {
-    is_set_ = true;
-    replacement_ = AssignUndefinedBefore(node);
-  }
-}
-
-
-void Processor::VisitContinueStatement(ContinueStatement* node) {
-  is_set_ = false;
-  replacement_ = node;
-}
-
-
-void Processor::VisitBreakStatement(BreakStatement* node) {
-  is_set_ = false;
-  replacement_ = node;
-}
-
-
-void Processor::VisitWithStatement(WithStatement* node) {
-  Visit(node->statement());
-  node->set_statement(replacement_);
-  replacement_ = node;
-
-  if (FLAG_harmony_completion && !is_set_) {
-    is_set_ = true;
-    replacement_ = AssignUndefinedBefore(node);
-  }
-}
-
-
-void Processor::VisitSloppyBlockFunctionStatement(
-    SloppyBlockFunctionStatement* node) {
-  Visit(node->statement());
-  node->set_statement(replacement_);
-  replacement_ = node;
-}
-
-
-void Processor::VisitEmptyStatement(EmptyStatement* node) {
-  replacement_ = node;
-}
-
-
-void Processor::VisitReturnStatement(ReturnStatement* node) {
-  is_set_ = true;
-  replacement_ = node;
-}
-
-
-void Processor::VisitDebuggerStatement(DebuggerStatement* node) {
-  replacement_ = node;
-}
-
-
-// Expressions are never visited.
-#define DEF_VISIT(type)                                         \
-  void Processor::Visit##type(type* expr) { UNREACHABLE(); }
-EXPRESSION_NODE_LIST(DEF_VISIT)
-#undef DEF_VISIT
-
-
-// Declarations are never visited.
-#define DEF_VISIT(type) \
-  void Processor::Visit##type(type* expr) { UNREACHABLE(); }
-DECLARATION_NODE_LIST(DEF_VISIT)
-#undef DEF_VISIT
-
-
-// Assumes code has been parsed.  Mutates the AST, so the AST should not
-// continue to be used in the case of failure.
-bool Rewriter::Rewrite(ParseInfo* info) {
-  FunctionLiteral* function = info->literal();
-  DCHECK(function != NULL);
-  Scope* scope = function->scope();
-  DCHECK(scope != NULL);
-  if (!scope->is_script_scope() && !scope->is_eval_scope()) return true;
-
-  ZoneList<Statement*>* body = function->body();
-  if (!body->is_empty()) {
-    Variable* result =
-        scope->NewTemporary(info->ast_value_factory()->dot_result_string());
-    // The name string must be internalized at this point.
-    DCHECK(!result->name().is_null());
-    Processor processor(info->isolate(), scope, result,
-                        info->ast_value_factory());
-    processor.Process(body);
-    if (processor.HasStackOverflow()) return false;
-
-    if (processor.result_assigned()) {
-      DCHECK(function->end_position() != RelocInfo::kNoPosition);
-      // Set the position of the assignment statement one character past the
-      // source code, such that it definitely is not in the source code range
-      // of an immediate inner scope. For example in
-      //   eval('with ({x:1}) x = 1');
-      // the end position of the function generated for executing the eval code
-      // coincides with the end of the with scope which is the position of '1'.
-      int pos = function->end_position();
-      VariableProxy* result_proxy =
-          processor.factory()->NewVariableProxy(result, pos);
-      Statement* result_statement =
-          processor.factory()->NewReturnStatement(result_proxy, pos);
-      body->Add(result_statement, info->zone());
-    }
-  }
-
-  return true;
-}
-
-
-bool Rewriter::Rewrite(Parser* parser, DoExpression* expr,
-                       AstValueFactory* factory) {
-  Block* block = expr->block();
-  Scope* scope = block->scope();
-  ZoneList<Statement*>* body = block->statements();
-  VariableProxy* result = expr->result();
-  Variable* result_var = result->var();
-
-  if (!body->is_empty()) {
-    Processor processor(parser, scope, result_var, factory);
-    processor.Process(body);
-    if (processor.HasStackOverflow()) return false;
-
-    if (!processor.result_assigned()) {
-      AstNodeFactory* node_factory = processor.factory();
-      Expression* undef =
-          node_factory->NewUndefinedLiteral(RelocInfo::kNoPosition);
-      Statement* completion = node_factory->NewExpressionStatement(
-          processor.SetResult(undef), expr->position());
-      body->Add(completion, factory->zone());
-    }
-  }
-  return true;
-}
-
-
-}  // namespace internal
-}  // namespace v8