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Unified Diff: src/rewriter.cc

Issue 1481613002: Create ast/ and parsing/ subdirectories and move appropriate files (Closed) Base URL: https://chromium.googlesource.com/v8/v8.git@master
Patch Set: Rebase Created 5 years, 1 month ago
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Index: src/rewriter.cc
diff --git a/src/rewriter.cc b/src/rewriter.cc
deleted file mode 100644
index 1f19739331e09feefcf5b75f352f8fa5729a31e4..0000000000000000000000000000000000000000
--- a/src/rewriter.cc
+++ /dev/null
@@ -1,403 +0,0 @@
-// 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
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