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LibJS: Integrate labels into the Interpreter

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The interpreter now considers a statement or block's label when
considering whether or not to break. All statements can be labelled.
This commit is contained in:
Matthew Olsson 2020-05-28 13:36:59 -07:00 • committed by Andreas Kling
parent 03615a7872
commit d52ea37717
6 changed files with 87 additions and 21 deletions
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22
Libraries/LibJS/AST.cpp
View file

@ -282,9 +282,9 @@ Value ForStatement::execute(Interpreter& interpreter) const
if (interpreter.exception())
return {};
if (interpreter.should_unwind()) {
if (interpreter.should_unwind_until(ScopeType::Continuable)) {
if (interpreter.should_unwind_until(ScopeType::Continuable, m_label)) {
interpreter.stop_unwind();
} else if (interpreter.should_unwind_until(ScopeType::Breakable)) {
} else if (interpreter.should_unwind_until(ScopeType::Breakable, m_label)) {
interpreter.stop_unwind();
break;
} else {
@ -303,9 +303,9 @@ Value ForStatement::execute(Interpreter& interpreter) const
if (interpreter.exception())
return {};
if (interpreter.should_unwind()) {
if (interpreter.should_unwind_until(ScopeType::Continuable)) {
if (interpreter.should_unwind_until(ScopeType::Continuable, m_label)) {
interpreter.stop_unwind();
} else if (interpreter.should_unwind_until(ScopeType::Breakable)) {
} else if (interpreter.should_unwind_until(ScopeType::Breakable, m_label)) {
interpreter.stop_unwind();
break;
} else {
@ -370,9 +370,9 @@ Value ForInStatement::execute(Interpreter& interpreter) const
if (interpreter.exception())
return {};
if (interpreter.should_unwind()) {
if (interpreter.should_unwind_until(ScopeType::Continuable)) {
if (interpreter.should_unwind_until(ScopeType::Continuable, m_label)) {
interpreter.stop_unwind();
} else if (interpreter.should_unwind_until(ScopeType::Breakable)) {
} else if (interpreter.should_unwind_until(ScopeType::Breakable, m_label)) {
interpreter.stop_unwind();
break;
} else {
@ -437,9 +437,9 @@ Value ForOfStatement::execute(Interpreter& interpreter) const
if (interpreter.exception())
return {};
if (interpreter.should_unwind()) {
if (interpreter.should_unwind_until(ScopeType::Continuable)) {
if (interpreter.should_unwind_until(ScopeType::Continuable, m_label)) {
interpreter.stop_unwind();
} else if (interpreter.should_unwind_until(ScopeType::Breakable)) {
} else if (interpreter.should_unwind_until(ScopeType::Breakable, m_label)) {
interpreter.stop_unwind();
break;
} else {
@ -1635,7 +1635,7 @@ Value SwitchStatement::execute(Interpreter& interpreter) const
if (interpreter.exception())
return {};
if (interpreter.should_unwind()) {
if (interpreter.should_unwind_until(ScopeType::Breakable)) {
if (interpreter.should_unwind_until(ScopeType::Breakable, m_label)) {
interpreter.stop_unwind();
return {};
}
@ -1655,13 +1655,13 @@ Value SwitchCase::execute(Interpreter& interpreter) const
Value BreakStatement::execute(Interpreter& interpreter) const
{
interpreter.unwind(ScopeType::Breakable);
interpreter.unwind(ScopeType::Breakable, m_target_label);
return js_undefined();
}
Value ContinueStatement::execute(Interpreter& interpreter) const
{
interpreter.unwind(ScopeType::Continuable);
interpreter.unwind(ScopeType::Continuable, m_target_label);
return js_undefined();
}

5
Libraries/LibJS/Interpreter.cpp
View file

@ -72,9 +72,12 @@ Value Interpreter::run(const Statement& statement, ArgumentVector arguments, Sco
m_last_value = js_undefined();
for (auto& node : block.children()) {
m_last_value = node.execute(*this);
if (m_unwind_until != ScopeType::None)
if (should_unwind()) {
if (should_unwind_until(ScopeType::Breakable, block.label()))
stop_unwind();
break;
}
}
bool did_return = m_unwind_until == ScopeType::Function;

14
Libraries/LibJS/Interpreter.h
View file

@ -91,9 +91,18 @@ public:
Heap& heap() { return m_heap; }
void unwind(ScopeType type) { m_unwind_until = type; }
void unwind(ScopeType type, FlyString label = {})
{
m_unwind_until = type;
m_unwind_until_label = label;
}
void stop_unwind() { m_unwind_until = ScopeType::None; }
bool should_unwind_until(ScopeType type) const { return m_unwind_until == type; }
bool should_unwind_until(ScopeType type, FlyString label) const
{
if (m_unwind_until_label.is_null())
return m_unwind_until == type;
return m_unwind_until == type && m_unwind_until_label == label;
}
bool should_unwind() const { return m_unwind_until != ScopeType::None; }
Value get_variable(const FlyString& name);
@ -189,6 +198,7 @@ private:
Exception* m_exception { nullptr };
ScopeType m_unwind_until { ScopeType::None };
FlyString m_unwind_until_label;
Console m_console;
};

6
Libraries/LibJS/Parser.cpp
View file

@ -269,9 +269,11 @@ NonnullRefPtr<Statement> Parser::parse_statement()
consume();
return create_ast_node<EmptyStatement>();
default:
if (match(TokenType::Identifier)) {
auto result = try_parse_labelled_statement();
if (!result.is_null())
return result.release_nonnull();
}
if (match_expression()) {
auto expr = parse_expression(0);
consume_or_insert_semicolon();
@ -1117,7 +1119,7 @@ NonnullRefPtr<BreakStatement> Parser::parse_break_statement()
consume();
return create_ast_node<BreakStatement>(target_label);
}
if (match_identifier_name() && !m_parser_state.m_current_token.trivia().contains('\n'))
if (match(TokenType::Identifier) && !m_parser_state.m_current_token.trivia().contains('\n'))
target_label = consume().value();
consume_or_insert_semicolon();
return create_ast_node<BreakStatement>(target_label);
@ -1131,7 +1133,7 @@ NonnullRefPtr<ContinueStatement> Parser::parse_continue_statement()
consume();
return create_ast_node<ContinueStatement>(target_label);
}
if (match_identifier_name() && !m_parser_state.m_current_token.trivia().contains('\n'))
if (match(TokenType::Identifier) && !m_parser_state.m_current_token.trivia().contains('\n'))
target_label = consume().value();
consume_or_insert_semicolon();
return create_ast_node<ContinueStatement>(target_label);

21
Libraries/LibJS/Tests/automatic-semicolon-insertion.js
View file

@ -25,9 +25,13 @@ function bar() {
}
function foo() {
label:
for (var i = 0; i < 4; i++) {
break // semicolon inserted here
continue // semicolon inserted here
break label // semicolon inserted here
continue label // semicolon inserted here
}
var j // semicolon inserted here
@ -39,8 +43,25 @@ function foo() {
1;
var curly/* semicolon inserted here */}
function baz() {
let counter = 0;
let outer;
outer:
for (let i = 0; i < 5; ++i) {
for (let j = 0; j < 5; ++j) {
continue // semicolon inserted here
outer // semicolon inserted here
}
counter++;
}
return counter;
}
try {
assert(foo() === undefined);
assert(baz() === 5);
console.log("PASS");
} catch (e) {

34
Libraries/LibJS/Tests/labels.js
View file

@ -1,12 +1,42 @@
load("test-common.js");
try {
test:
{
test: {
let o = 1;
assert(o === 1);
break test;
assertNotReached();
}
outer: {
{
break outer;
}
assertNotReached();
}
let counter = 0;
outer:
for (a of [1, 2, 3]) {
for (b of [4, 5, 6]) {
if (a === 2 && b === 5)
break outer;
counter++;
}
}
assert(counter === 4);
let counter = 0;
outer:
for (a of [1, 2, 3]) {
for (b of [4, 5, 6]) {
if (b === 6)
continue outer;
counter++;
}
}
assert(counter === 6);
console.log("PASS");
} catch (e) {
console.log("FAIL: " + e);