Reduce bytecode instruction count emitted for `class extends`
https://bugs.webkit.org/show_bug.cgi?id=223884
Reviewed by Yusuke Suzuki.
JSTests:
* ChakraCore/test/Error/validate_line_column.baseline-jsc:
Source/JavaScriptCore:
This patch adds a variant of globalFuncSetPrototypeDirect() that throws on
invalid [[Prototype]] values (instead of ignoring them) and utilizes it in
ClassExprNode::emitBytecode(), removing equivalent checks.
Throwing for invalid `superclass.prototype` value after setting the [[Prototype]]
of `constructor` is unobservable because it's a newly created extensible object
and `superclass` is a proven object.
The fact that [[Prototype]] set can throw only in case of `superclass.prototype`
allows keeping descriptive error message via custom appender. To find "extends"
in a source code, ClassExprNode is made an instance of ThrowableExpressionData.
This change reduces the number of emitted bytecodes by 4, and fixes IsConstructor's
error [1] to point to correct source code location.
[1]: https://tc39.es/ecma262/#sec-runtime-semantics-classdefinitionevaluation (step 5.f)
* builtins/BuiltinNames.h:
* bytecode/LinkTimeConstant.h:
* bytecompiler/BytecodeGenerator.cpp:
(JSC::BytecodeGenerator::emitDirectSetPrototypeOf):
* bytecompiler/BytecodeGenerator.h:
* bytecompiler/NodesCodegen.cpp:
(JSC::PropertyListNode::emitPutConstantProperty):
(JSC::ClassExprNode::emitBytecode):
* parser/ASTBuilder.h:
(JSC::ASTBuilder::createClassExpr):
* parser/Nodes.h:
* parser/Parser.cpp:
(JSC::Parser<LexerType>::parseClass):
* parser/SyntaxChecker.h:
(JSC::SyntaxChecker::createClassExpr):
* runtime/ExceptionHelpers.cpp:
(JSC::invalidPrototypeSourceAppender):
(JSC::createInvalidPrototypeError):
* runtime/ExceptionHelpers.h:
* runtime/JSGlobalObject.cpp:
(JSC::JSGlobalObject::init):
* runtime/JSGlobalObjectFunctions.cpp:
(JSC::JSC_DEFINE_HOST_FUNCTION):
* runtime/JSGlobalObjectFunctions.h:
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@275439 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.h b/Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.h
index a765428..52aa1ed 100644
--- a/Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.h
+++ b/Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.h
@@ -52,6 +52,7 @@
JSC_DECLARE_HOST_FUNCTION(globalFuncProtoGetter);
JSC_DECLARE_HOST_FUNCTION(globalFuncProtoSetter);
JSC_DECLARE_HOST_FUNCTION(globalFuncSetPrototypeDirect);
+JSC_DECLARE_HOST_FUNCTION(globalFuncSetPrototypeDirectOrThrow);
JSC_DECLARE_HOST_FUNCTION(globalFuncHostPromiseRejectionTracker);
JSC_DECLARE_HOST_FUNCTION(globalFuncBuiltinLog);
JSC_DECLARE_HOST_FUNCTION(globalFuncBuiltinDescribe);
