Changeset 220068 in webkit

Timestamp:

Jul 31, 2017, 9:15:32 AM (7 years ago)

Author:

Yusuke Suzuki

Message:

[JSC] Support optional catch binding
​https://bugs.webkit.org/show_bug.cgi?id=174981

Reviewed by Saam Barati.

JSTests:

• stress/optional-catch-binding-syntax.js: Added.

(testSyntax):
(testSyntaxError):
(catch.catch):

• stress/optional-catch-binding.js: Added.

(shouldBe):
(throwException):

Source/JavaScriptCore:

This patch implements optional catch binding proposal[1], which is now stage 3.
This proposal adds a new catch brace with no error value binding.

`

try {

...

} catch {

...

}

`

Sometimes we do not need to get error value actually. For example, the function returns
boolean which means whether the function succeeds.

`
function parse(result) -> bool
{

try {

parseInner(result);

} catch {

return false;

}
return true;

}
`

In the above case, we are not interested in the actual error value. Without this syntax,
we always need to introduce a binding for an error value that is just ignored.

[1]: ​https://michaelficarra.github.io/optional-catch-binding-proposal/

• bytecompiler/NodesCodegen.cpp:

(JSC::TryNode::emitBytecode):

• parser/Parser.cpp:

(JSC::Parser<LexerType>::parseTryStatement):

LayoutTests:

Rebaseline existing tests.

• js/parser-syntax-check-expected.txt:
• js/script-tests/parser-syntax-check.js:
• sputnik/Conformance/12_Statement/12.14_The_try_Statement/S12.14_A16_T4-expected.txt:
• sputnik/Conformance/12_Statement/12.14_The_try_Statement/S12.14_A16_T4.html:

Location:

trunk

Files:

• JSTests/ChangeLog (modified) (1 diff)
• JSTests/stress/optional-catch-binding-syntax.js (added)
• JSTests/stress/optional-catch-binding.js (added)
• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/js/parser-syntax-check-expected.txt (modified) (1 diff)
• LayoutTests/js/script-tests/parser-syntax-check.js (modified) (1 diff)
• LayoutTests/sputnik/Conformance/12_Statement/12.14_The_try_Statement/S12.14_A16_T4-expected.txt (modified) (1 diff)
• LayoutTests/sputnik/Conformance/12_Statement/12.14_The_try_Statement/S12.14_A16_T4.html (modified) (1 diff)
• Source/JavaScriptCore/ChangeLog (modified) (1 diff)
• Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp (modified) (2 diffs)
• Source/JavaScriptCore/parser/Parser.cpp (modified) (1 diff)

trunk/JSTests/ChangeLog

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 2017-07-28  Mark Lam  <mark.lam@apple.com>
 

trunk/LayoutTests/ChangeLog

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 2017-07-31  Per Arne Vollan  <pvollan@apple.com>
 

trunk/LayoutTests/js/parser-syntax-check-expected.txt

@@ -632 +632 @@
 PASS Invalid: "try {} catch (...) {}". Produced the following syntax error: "SyntaxError: Unexpected token '...'. Expected a parameter pattern or a ')' in parameter list."
 PASS Invalid: "function f() { try {} catch (...) {} }". Produced the following syntax error: "SyntaxError: Unexpected token '...'. Expected a parameter pattern or a ')' in parameter list."
-PASS Invalid: "try {} catch {}". Produced the following syntax error: "SyntaxError: Unexpected token '{'. Expected '(' to start a 'catch' target."
-PASS Invalid: "function f() { try {} catch {} }". Produced the following syntax error: "SyntaxError: Unexpected token '{'. Expected '(' to start a 'catch' target."
+PASS "
+PASS "
 PASS Valid:   "if (a) try {} finally {} else b;"
 PASS Valid:   "function f() { if (a) try {} finally {} else b; }"

trunk/LayoutTests/js/script-tests/parser-syntax-check.js

@@ -412 +412 @@
 invalid("try {} finally {} catch(e) {}");
 invalid("try {} catch (...) {}");
-invalid("try {} catch {}");
+("try {} catch {}");
 valid  ("if (a) try {} finally {} else b;");
 valid  ("if (--a()) do with(1) try {} catch(ke) { f() ; g() } while (a in b) else {}");

trunk/LayoutTests/sputnik/Conformance/12_Statement/12.14_The_try_Statement/S12.14_A16_T4-expected.txt

@@ -1 @@
-CONSOLE MESSAGE: line 78: SyntaxError: Unexpected token '{'. Expected '(' to start a 'catch' target.
 S12.14_A16_T4
 
-PASS Expected parsing failure
+PASS 
 
 TEST COMPLETE

trunk/LayoutTests/sputnik/Conformance/12_Statement/12.14_The_try_Statement/S12.14_A16_T4.html

@@ -87 +87 @@
 <script>
 if (!successfullyParsed)
-    printTestPassed('Expected parsing failure');
+    printTested('Expected parsing failure');
 else if (sputnikException)
-    printTestPassed(sputnikException);
+    printTested(sputnikException);
 else
-    printTestFailed("No error detected");
+    printTested("No error detected");
 testPrint('<br /><span class="pass">TEST COMPLETE</span>');
 </script>

trunk/Source/JavaScriptCore/ChangeLog

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 2017-07-31  Yusuke Suzuki  <utatane.tea@gmail.com>
 

trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp

@@ -3414 +3414 @@
         }
 
-        generator.emitPushCatchScope(m_lexicalVariables);
-        m_catchPattern->bindValue(generator, thrownValueRegister.get());
+        if (m_catchPattern) {
+            generator.emitPushCatchScope(m_lexicalVariables);
+            m_catchPattern->bindValue(generator, thrownValueRegister.get());
+        }
+
         generator.emitProfileControlFlow(m_tryBlock->endOffset() + 1);
         if (m_finallyBlock)
@@ -3422 +3425 @@
             generator.emitNodeInTailPosition(dst, m_catchBlock);
         generator.emitLoad(thrownValueRegister.get(), jsUndefined());
-        generator.emitPopCatchScope(m_lexicalVariables);
+
+        if (m_catchPattern)
+            generator.emitPopCatchScope(m_lexicalVariables);
 
         if (m_finallyBlock) {

trunk/Source/JavaScriptCore/parser/Parser.cpp

@@ -1634 +1634 @@
         next();
         
-        handleProductionOrFail(OPENPAREN, "(", "start", "'catch' target");
-        AutoPopScopeRef catchScope(this, pushScope());
-        catchScope->setIsLexicalScope();
-        catchScope->preventVarDeclarations();
-        const Identifier* ident = nullptr;
-        if (matchSpecIdentifier()) {
-            ident = m_token.m_data.ident;
-            catchPattern = context.createBindingLocation(m_token.m_location, *ident, m_token.m_startPosition, m_token.m_endPosition, AssignmentContext::DeclarationStatement);
-            next();
-            failIfTrueIfStrict(catchScope->declareLexicalVariable(ident, false) & DeclarationResult::InvalidStrictMode, "Cannot declare a catch variable named '", ident->impl(), "' in strict mode");
+        if (match(OPENBRACE)) {
+            catchBlock = parseBlockStatement(context);
+            failIfFalse(catchBlock, "Unable to parse 'catch' block");
         } else {
-            catchPattern = parseDestructuringPattern(context, DestructuringKind::DestructureToCatchParameters, ExportType::NotExported);
-            failIfFalse(catchPattern, "Cannot parse this destructuring pattern");
-        }
-        handleProductionOrFail(CLOSEPAREN, ")", "end", "'catch' target");
-        matchOrFail(OPENBRACE, "Expected exception handler to be a block statement");
-        catchBlock = parseBlockStatement(context);
-        failIfFalse(catchBlock, "Unable to parse 'catch' block");
-        catchEnvironment = catchScope->finalizeLexicalEnvironment();
-        RELEASE_ASSERT(!ident || (catchEnvironment.size() == 1 && catchEnvironment.contains(ident->impl())));
-        popScope(catchScope, TreeBuilder::NeedsFreeVariableInfo);
+            handleProductionOrFail(OPENPAREN, "(", "start", "'catch' target");
+            AutoPopScopeRef catchScope(this, pushScope());
+            catchScope->setIsLexicalScope();
+            catchScope->preventVarDeclarations();
+            const Identifier* ident = nullptr;
+            if (matchSpecIdentifier()) {
+                ident = m_token.m_data.ident;
+                catchPattern = context.createBindingLocation(m_token.m_location, *ident, m_token.m_startPosition, m_token.m_endPosition, AssignmentContext::DeclarationStatement);
+                next();
+                failIfTrueIfStrict(catchScope->declareLexicalVariable(ident, false) & DeclarationResult::InvalidStrictMode, "Cannot declare a catch variable named '", ident->impl(), "' in strict mode");
+            } else {
+                catchPattern = parseDestructuringPattern(context, DestructuringKind::DestructureToCatchParameters, ExportType::NotExported);
+                failIfFalse(catchPattern, "Cannot parse this destructuring pattern");
+            }
+            handleProductionOrFail(CLOSEPAREN, ")", "end", "'catch' target");
+            matchOrFail(OPENBRACE, "Expected exception handler to be a block statement");
+            catchBlock = parseBlockStatement(context);
+            failIfFalse(catchBlock, "Unable to parse 'catch' block");
+            catchEnvironment = catchScope->finalizeLexicalEnvironment();
+            RELEASE_ASSERT(!ident || (catchEnvironment.size() == 1 && catchEnvironment.contains(ident->impl())));
+            popScope(catchScope, TreeBuilder::NeedsFreeVariableInfo);
+        }
     }