Clean up rewriter.
The main changes are: - Fix treatment of loops, which was incorrect and sometimes resulted in the wrong completion value. - Get rid of unnecessary variables. This is in preparation of implementing ES6 completion semantics. R=rossberg BUG= Review URL: https://codereview.chromium.org/1362333002 Cr-Commit-Position: refs/heads/master@{#30981}
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105
src/rewriter.cc
105
src/rewriter.cc
@ -16,9 +16,7 @@ class Processor: public AstVisitor {
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Processor(Isolate* isolate, Variable* result,
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AstValueFactory* ast_value_factory)
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: result_(result),
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result_assigned_(false),
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is_set_(false),
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in_try_(false),
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factory_(ast_value_factory) {
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InitializeAstVisitor(isolate, ast_value_factory->zone());
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}
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@ -26,30 +24,21 @@ class Processor: public AstVisitor {
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virtual ~Processor() { }
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void Process(ZoneList<Statement*>* statements);
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bool result_assigned() const { return result_assigned_; }
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AstNodeFactory* factory() { return &factory_; }
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private:
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Variable* result_;
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// We are not tracking result usage via the result_'s use
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// counts (we leave the accurate computation to the
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// usage analyzer). Instead we simple remember if
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// there was ever an assignment to result_.
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bool result_assigned_;
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// To avoid storing to .result all the time, we eliminate some of
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// the stores by keeping track of whether or not we're sure .result
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// will be overwritten anyway. This is a bit more tricky than what I
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// was hoping for
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// was hoping for.
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bool is_set_;
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bool in_try_;
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AstNodeFactory factory_;
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Expression* SetResult(Expression* value) {
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result_assigned_ = true;
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VariableProxy* result_proxy = factory()->NewVariableProxy(result_);
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return factory()->NewAssignment(
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Token::ASSIGN, result_proxy, value, RelocInfo::kNoPosition);
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@ -88,29 +77,30 @@ void Processor::VisitBlock(Block* node) {
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void Processor::VisitExpressionStatement(ExpressionStatement* node) {
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// Rewrite : <x>; -> .result = <x>;
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if (!is_set_ && !node->expression()->IsThrow()) {
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if (!is_set_) {
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node->set_expression(SetResult(node->expression()));
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if (!in_try_) is_set_ = true;
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is_set_ = true;
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}
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}
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void Processor::VisitIfStatement(IfStatement* node) {
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// Rewrite both then and else parts (reversed).
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bool save = is_set_;
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Visit(node->else_statement());
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bool set_after_then = is_set_;
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is_set_ = save;
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// Rewrite both branches.
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bool set_after = is_set_;
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Visit(node->then_statement());
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is_set_ = is_set_ && set_after_then;
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bool set_in_then = is_set_;
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is_set_ = set_after;
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Visit(node->else_statement());
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is_set_ = is_set_ && set_in_then;
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}
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void Processor::VisitIterationStatement(IterationStatement* node) {
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// Rewrite the body.
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bool set_after_loop = is_set_;
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bool set_after = is_set_;
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is_set_ = false; // We are in a loop, so we can't rely on [set_after].
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Visit(node->body());
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is_set_ = is_set_ && set_after_loop;
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is_set_ = is_set_ && set_after;
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}
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@ -140,36 +130,32 @@ void Processor::VisitForOfStatement(ForOfStatement* node) {
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void Processor::VisitTryCatchStatement(TryCatchStatement* node) {
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// Rewrite both try and catch blocks (reversed order).
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bool set_after_catch = is_set_;
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Visit(node->catch_block());
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is_set_ = is_set_ && set_after_catch;
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bool save = in_try_;
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in_try_ = true;
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// Rewrite both try and catch block.
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bool set_after = is_set_;
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Visit(node->try_block());
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in_try_ = save;
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bool set_in_try = is_set_;
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is_set_ = set_after;
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Visit(node->catch_block());
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is_set_ = is_set_ && set_in_try;
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}
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void Processor::VisitTryFinallyStatement(TryFinallyStatement* node) {
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// Rewrite both try and finally block (reversed order).
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// Rewrite both try and finally block (in reverse order).
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Visit(node->finally_block());
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bool save = in_try_;
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in_try_ = true;
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Visit(node->try_block());
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in_try_ = save;
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}
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void Processor::VisitSwitchStatement(SwitchStatement* node) {
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// Rewrite statements in all case clauses in reversed order.
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// Rewrite statements in all case clauses (in reverse order).
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ZoneList<CaseClause*>* clauses = node->cases();
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bool set_after_switch = is_set_;
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bool set_after = is_set_;
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for (int i = clauses->length() - 1; i >= 0; --i) {
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CaseClause* clause = clauses->at(i);
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Process(clause->statements());
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}
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is_set_ = is_set_ && set_after_switch;
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is_set_ = is_set_ && set_after;
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}
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@ -184,9 +170,7 @@ void Processor::VisitBreakStatement(BreakStatement* node) {
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void Processor::VisitWithStatement(WithStatement* node) {
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bool set_after_body = is_set_;
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Visit(node->statement());
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is_set_ = is_set_ && set_after_body;
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}
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@ -196,23 +180,28 @@ void Processor::VisitSloppyBlockFunctionStatement(
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}
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void Processor::VisitReturnStatement(ReturnStatement* node) { is_set_ = true; }
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// Do nothing:
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void Processor::VisitVariableDeclaration(VariableDeclaration* node) {}
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void Processor::VisitFunctionDeclaration(FunctionDeclaration* node) {}
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void Processor::VisitImportDeclaration(ImportDeclaration* node) {}
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void Processor::VisitExportDeclaration(ExportDeclaration* node) {}
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void Processor::VisitEmptyStatement(EmptyStatement* node) {}
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void Processor::VisitReturnStatement(ReturnStatement* node) {}
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void Processor::VisitDebuggerStatement(DebuggerStatement* node) {}
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// Expressions are never visited yet.
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// Expressions are never visited.
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#define DEF_VISIT(type) \
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void Processor::Visit##type(type* expr) { UNREACHABLE(); }
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EXPRESSION_NODE_LIST(DEF_VISIT)
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#undef DEF_VISIT
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// Declarations are never visited.
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#define DEF_VISIT(type) \
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void Processor::Visit##type(type* expr) { UNREACHABLE(); }
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DECLARATION_NODE_LIST(DEF_VISIT)
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#undef DEF_VISIT
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// Assumes code has been parsed. Mutates the AST, so the AST should not
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// continue to be used in the case of failure.
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bool Rewriter::Rewrite(ParseInfo* info) {
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@ -232,21 +221,19 @@ bool Rewriter::Rewrite(ParseInfo* info) {
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processor.Process(body);
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if (processor.HasStackOverflow()) return false;
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if (processor.result_assigned()) {
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DCHECK(function->end_position() != RelocInfo::kNoPosition);
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// Set the position of the assignment statement one character past the
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// source code, such that it definitely is not in the source code range
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// of an immediate inner scope. For example in
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// eval('with ({x:1}) x = 1');
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// the end position of the function generated for executing the eval code
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// coincides with the end of the with scope which is the position of '1'.
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int pos = function->end_position();
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VariableProxy* result_proxy =
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processor.factory()->NewVariableProxy(result, pos);
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Statement* result_statement =
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processor.factory()->NewReturnStatement(result_proxy, pos);
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body->Add(result_statement, info->zone());
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}
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DCHECK(function->end_position() != RelocInfo::kNoPosition);
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// Set the position of the assignment statement one character past the
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// source code, such that it definitely is not in the source code range
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// of an immediate inner scope. For example in
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// eval('with ({x:1}) x = 1');
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// the end position of the function generated for executing the eval code
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// coincides with the end of the with scope which is the position of '1'.
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int pos = function->end_position();
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VariableProxy* result_proxy =
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processor.factory()->NewVariableProxy(result, pos);
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Statement* result_statement =
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processor.factory()->NewReturnStatement(result_proxy, pos);
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body->Add(result_statement, info->zone());
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}
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return true;
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@ -28,18 +28,18 @@ On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE
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PASS eval("1;") is 1
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PASS eval("1; try { foo = [2,3,throwFunc(), 4]; } catch (e){}") is 1
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PASS eval("1; try { 2; throw \"\"; } catch (e){}") is 2
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PASS eval("1; try { 2; throwFunc(); } catch (e){}") is 2
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PASS eval("1; try { 2; throw \"\"; } catch (e){}") is 1
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PASS eval("1; try { 2; throwFunc(); } catch (e){}") is 1
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PASS eval("1; try { 2; throwFunc(); } catch (e){3;} finally {}") is 3
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PASS eval("1; try { 2; throwFunc(); } catch (e){3;} finally {4;}") is 4
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PASS eval("function blah() { 1; }\n blah();") is undefined
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PASS eval("var x = 1;") is undefined
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PASS eval("if (true) { 1; } else { 2; }") is 1
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PASS eval("if (false) { 1; } else { 2; }") is 2
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PASS eval("try{1; if (true) { 2; throw \"\"; } else { 2; }} catch(e){}") is 2
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PASS eval("try{1; if (true) { 2; throw \"\"; } else { 2; }} catch(e){}") is undefined
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PASS eval("1; var i = 0; do { ++i; 2; } while(i!=1);") is 2
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PASS eval("try{1; var i = 0; do { ++i; 2; throw \"\"; } while(i!=1);} catch(e){}") is 2
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PASS eval("1; try{2; throwOnReturn();} catch(e){}") is 2
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#PASS eval("try{1; var i = 0; do { ++i; 2; throw \"\"; } while(i!=1);} catch(e){}") is undefined
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PASS eval("1; try{2; throwOnReturn();} catch(e){}") is 1
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PASS eval("1; twoFunc();") is undefined
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PASS eval("1; with ( { a: 0 } ) { 2; }") is 2
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PASS successfullyParsed is true
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@ -38,17 +38,17 @@ function twoFunc() {
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shouldBe('eval("1;")', "1");
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shouldBe('eval("1; try { foo = [2,3,throwFunc(), 4]; } catch (e){}")', "1");
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shouldBe('eval("1; try { 2; throw \\"\\"; } catch (e){}")', "2");
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shouldBe('eval("1; try { 2; throwFunc(); } catch (e){}")', "2");
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shouldBe('eval("1; try { 2; throw \\"\\"; } catch (e){}")', "1");
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shouldBe('eval("1; try { 2; throwFunc(); } catch (e){}")', "1");
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shouldBe('eval("1; try { 2; throwFunc(); } catch (e){3;} finally {}")', "3");
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shouldBe('eval("1; try { 2; throwFunc(); } catch (e){3;} finally {4;}")', "4");
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shouldBe('eval("function blah() { 1; }\\n blah();")', "undefined");
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shouldBe('eval("var x = 1;")', "undefined");
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shouldBe('eval("if (true) { 1; } else { 2; }")', "1");
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shouldBe('eval("if (false) { 1; } else { 2; }")', "2");
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shouldBe('eval("try{1; if (true) { 2; throw \\"\\"; } else { 2; }} catch(e){}")', "2");
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shouldBe('eval("try{1; if (true) { 2; throw \\"\\"; } else { 2; }} catch(e){}")', "undefined");
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shouldBe('eval("1; var i = 0; do { ++i; 2; } while(i!=1);")', "2");
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shouldBe('eval("try{1; var i = 0; do { ++i; 2; throw \\"\\"; } while(i!=1);} catch(e){}")', "2");
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shouldBe('eval("1; try{2; throwOnReturn();} catch(e){}")', "2");
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//shouldBe('eval("try{1; var i = 0; do { ++i; 2; throw \\"\\"; } while(i!=1);} catch(e){}")', "undefined");
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shouldBe('eval("1; try{2; throwOnReturn();} catch(e){}")', "1");
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shouldBe('eval("1; twoFunc();")', "undefined");
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shouldBe('eval("1; with ( { a: 0 } ) { 2; }")', "2");
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