Changeset 292830 in webkit for trunk/Source/JavaScriptCore/debugger/Debugger.cpp

Timestamp:

Apr 13, 2022, 2:01:19 PM (3 years ago)

Author:

[email protected]

Message:

[JSC] Remove DeprecatedCallFrameForDebugger
​https://bugs.webkit.org/show_bug.cgi?id=239045

Reviewed by Devin Rousso.

We should not enlarge sizeof(JSGlobalObject) by having DeprecatedCallFrameForDebugger which is only used for Debugger, and it is used
only when we have an error when evaluating top-level SyntaxError. This patch removes it: we introduce EmptyTopLevelCallFrameForDebugger
which can be constructed on stack and we use it instead of DeprecatedCallFrameForDebugger.

• Source/JavaScriptCore/debugger/Debugger.cpp:

(JSC::Debugger::updateCallFrame):
(JSC::EmptyTopLevelCallFrameForDebugger::EmptyTopLevelCallFrameForDebugger):
(JSC::EmptyTopLevelCallFrameForDebugger::asCallFrame):
(JSC::Debugger::exception):

• Source/JavaScriptCore/debugger/DebuggerCallFrame.cpp:

(JSC::DebuggerCallFrame::create):
(JSC::DebuggerCallFrame::positionForCallFrame):

• Source/JavaScriptCore/interpreter/CallFrame.cpp:

(JSC::CallFrame::convertToStackOverflowFrame):
(JSC::CallFrame::initDeprecatedCallFrameForDebugger): Deleted.

• Source/JavaScriptCore/interpreter/CallFrame.h:

(JSC::CallFrame::isEmptyTopLevelCallFrameForDebugger const):
(JSC::CallFrame::isDeprecatedCallFrameForDebugger const): Deleted.

• Source/JavaScriptCore/interpreter/Interpreter.cpp:

(JSC::Interpreter::notifyDebuggerOfExceptionToBeThrown):

• Source/JavaScriptCore/runtime/JSGlobalObject.cpp:

(JSC::JSGlobalObject::init):
(JSC::JSGlobalObject::deprecatedCallFrameForDebugger): Deleted.

• Source/JavaScriptCore/runtime/JSGlobalObject.h:
• Source/JavaScriptCore/runtime/VM.cpp:

(JSC::VM::throwException):

Canonical link: ​https://commits.webkit.org/249603@main

File:

• trunk/Source/JavaScriptCore/debugger/Debugger.cpp (modified) (3 diffs)

trunk/Source/JavaScriptCore/debugger/Debugger.cpp

@@ -1036 +1036 @@
 }
 
+class EmptyTopLevelCallFrameForDebugger {
+public:
+    EmptyTopLevelCallFrameForDebugger(JSGlobalObject* globalObject)
+    {
+        CallFrame* callFrame = asCallFrame();
+        callFrame->setCodeBlock(nullptr);
+        callFrame->setCallerFrame(CallFrame::noCaller());
+        callFrame->setReturnPC(nullptr);
+        callFrame->setArgumentCountIncludingThis(1);
+        callFrame->setThisValue(globalObject->globalThis());
+        callFrame->setCallee(globalObject->globalCallee());
+        ASSERT(callFrame->isEmptyTopLevelCallFrameForDebugger());
+    }
+
+    CallFrame* asCallFrame() { return CallFrame::create(m_values); }
+
+private:
+    Register m_values[CallFrame::headerSizeInRegisters + /* thisValue */ 1] { };
+};
+
 void Debugger::exception(JSGlobalObject* globalObject, CallFrame* callFrame, JSValue exception, bool hasCatchHandler)
 {
@@ -1057 +1077 @@
     }
 
+    // When callFrame is nullptr, we are throwing an error without JS call frames.
+    // This can happen when program throws SyntaxError without evaluation.
+    EmptyTopLevelCallFrameForDebugger emptyCallFrame(globalObject);
+    bool callFrameWasNull = !callFrame;
+    if (callFrameWasNull)
+        callFrame = emptyCallFrame.asCallFrame();
+
     m_hasHandlerForExceptionCallback = true;
     m_currentException = exception;
@@ -1062 +1089 @@
     m_currentException = JSValue();
     m_hasHandlerForExceptionCallback = false;
+
+    if (callFrameWasNull)
+        m_currentCallFrame = nullptr;
 }