Attachment 343406 Details for Bug 186947 – proposed patch.

[patch] proposed patch.

bug-186947.patch (text/plain), 12.88 KB, created by Mark Lam on 2018-06-22 18:17:51 PDT

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Creator: Mark Lam

Created: 2018-06-22 18:17:51 PDT

Size: 12.88 KB

patch

obsolete

>Index: Source/JavaScriptCore/ChangeLog
>===================================================================
>--- Source/JavaScriptCore/ChangeLog	(revision 233115)
>+++ Source/JavaScriptCore/ChangeLog	(working copy)
>@@ -1,3 +1,57 @@
>+2018-06-22  Mark Lam  <mark.lam@apple.com>
>+
>+        Add more debugging features to $vm.
>+        https://bugs.webkit.org/show_bug.cgi?id=186947
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        Adding the following features:
>+
>+            // We now have println in addition to print.
>+            // println automatically adds a '\n' at the end.
>+            $vm.println("Hello");
>+
>+            // We can now capture some info about a stack frame.
>+            var currentFrame = $vm.callFrame(); // Same as $vm.callFrame(0);
>+            var callerCallerFrame = $vm.callFrame(2);
>+
>+            // We can inspect the following values associated with the frame:
>+            if (currentFrame.valid) {
>+                $vm.println("name is ", currentFrame.name));
>+                $vm.println("callee is ", $vm.value(currentFrame.callee));
>+                $vm.println("codeBlock is ", currentFrame.codeBlock);
>+                $vm.println("unlinkedCodeBlock is ", currentFrame.unlinkedCodeBlock);
>+                $vm.println("executable is ", currentFrame.executable);
>+            }
>+
>+            // Note that callee is a JSObject.  I printed its $vm.value() because I wanted
>+            // to dataLog its JSValue instead of its toString() result.
>+
>+            // Note that $vm.println() (and $vm.print()) can now print internal JSCells
>+            // (and Symbols) as JSValue dumps. It won't just fail on trying to do a
>+            // toString on a non-object.
>+
>+            // Does what it says about enabling/disabling debugger mode.
>+            $vm.enableDebuggerModeWhenIdle();
>+            $vm.disableDebuggerModeWhenIdle();
>+
>+        * tools/JSDollarVM.cpp:
>+        (WTF::JSDollarVMCallFrame::JSDollarVMCallFrame):
>+        (WTF::JSDollarVMCallFrame::createStructure):
>+        (WTF::JSDollarVMCallFrame::create):
>+        (WTF::JSDollarVMCallFrame::finishCreation):
>+        (WTF::JSDollarVMCallFrame::addProperty):
>+        (JSC::functionCallFrame):
>+        (JSC::functionCodeBlockForFrame):
>+        (JSC::codeBlockFromArg):
>+        (JSC::doPrintln):
>+        (JSC::functionPrint):
>+        (JSC::functionPrintln):
>+        (JSC::changeDebuggerModeWhenIdle):
>+        (JSC::functionEnableDebuggerModeWhenIdle):
>+        (JSC::functionDisableDebuggerModeWhenIdle):
>+        (JSC::JSDollarVM::finishCreation):
>+
> 2018-06-22  Mark Lam  <mark.lam@apple.com>
> 
>         PropertyCondition::isValidValueForAttributes() should also consider deleted values.
>Index: Source/JavaScriptCore/tools/JSDollarVM.cpp
>===================================================================
>--- Source/JavaScriptCore/tools/JSDollarVM.cpp	(revision 233107)
>+++ Source/JavaScriptCore/tools/JSDollarVM.cpp	(working copy)
>@@ -1,5 +1,5 @@
> /*
>- * Copyright (C) 2015-2017 Apple Inc. All rights reserved.
>+ * Copyright (C) 2015-2018 Apple Inc. All rights reserved.
>  *
>  * Redistribution and use in source and binary forms, with or without
>  * modification, are permitted provided that the following conditions
>@@ -56,6 +56,71 @@ using namespace WTF;
> 
> namespace {
> 
>+class JSDollarVMCallFrame : public JSDestructibleObject {
>+    using Base = JSDestructibleObject;
>+public:
>+    JSDollarVMCallFrame(VM& vm, Structure* structure)
>+        : Base(vm, structure)
>+    { }
>+
>+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
>+    {
>+        return Structure::create(vm, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), info());
>+    }
>+
>+    static JSDollarVMCallFrame* create(ExecState* exec, unsigned requestedFrameIndex)
>+    {
>+        VM& vm = exec->vm();
>+        JSGlobalObject* globalObject = exec->lexicalGlobalObject();
>+        Structure* structure = createStructure(vm, globalObject, jsNull());
>+        JSDollarVMCallFrame* frame = new (NotNull, allocateCell<JSDollarVMCallFrame>(vm.heap, sizeof(JSDollarVMCallFrame))) JSDollarVMCallFrame(vm, structure);
>+        frame->finishCreation(vm, exec, requestedFrameIndex);
>+        return frame;
>+    }
>+
>+    void finishCreation(VM& vm, CallFrame* frame, unsigned requestedFrameIndex)
>+    {
>+        Base::finishCreation(vm);
>+
>+        auto addProperty = [&] (VM& vm, const char* name, JSValue value) {
>+            JSDollarVMCallFrame::addProperty(vm, name, value);
>+        };
>+
>+        unsigned frameIndex = 0;
>+        bool isValid = false;
>+        frame->iterate([&] (StackVisitor& visitor) {
>+
>+            if (frameIndex++ != requestedFrameIndex)
>+                return StackVisitor::Continue;
>+
>+            if (visitor->callee().isCell())
>+                addProperty(vm, "callee", visitor->callee().asCell());
>+
>+            addProperty(vm, "name", jsString(&vm, visitor->functionName()));
>+            CodeBlock* codeBlock = visitor->codeBlock();
>+            addProperty(vm, "codeBlock", codeBlock);
>+            addProperty(vm, "unlinkedCodeBlock", codeBlock->unlinkedCodeBlock());
>+            addProperty(vm, "executable", codeBlock->ownerExecutable());
>+            isValid = true;
>+
>+            return StackVisitor::Done;
>+        });
>+
>+        addProperty(vm, "valid", jsBoolean(isValid));
>+    }
>+
>+    DECLARE_INFO;
>+
>+private:
>+    void addProperty(VM& vm, const char* name, JSValue value)
>+    {
>+        Identifier identifier = Identifier::fromString(&vm, name);
>+        putDirect(vm, identifier, value);
>+    }
>+};
>+
>+const ClassInfo JSDollarVMCallFrame::s_info = { "CallFrame", &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(JSDollarVMCallFrame) };
>+
> class ElementHandleOwner;
> class Root;
> 
>@@ -1245,26 +1310,45 @@ static EncodedJSValue JSC_HOST_CALL func
>     return JSValue::encode(jsUndefined());
> }
> 
>+// Gets a JSDollarVMCallFrame for a specified frame index.
>+// Usage: var callFrame = $vm.callFrame(0) // frame 0 is the top frame.
>+// Usage: var callFrame = $vm.callFrame() // implies frame 0 i.e. current frame.
>+static EncodedJSValue JSC_HOST_CALL functionCallFrame(ExecState* exec)
>+{
>+    unsigned frameNumber = 1;
>+    if (exec->argumentCount() >= 1) {
>+        JSValue value = exec->uncheckedArgument(0);
>+        if (!value.isUInt32())
>+            return JSValue::encode(jsUndefined());
>+
>+        // We need to inc the frame number because the caller would consider
>+        // its own frame as frame 0. Hence, we need discount the frame for this
>+        // function.
>+        frameNumber = value.asUInt32() + 1;
>+    }
>+
>+    return JSValue::encode(JSDollarVMCallFrame::create(exec, frameNumber));
>+}
>+
> // Gets a token for the CodeBlock for a specified frame index.
> // Usage: codeBlockToken = $vm.codeBlockForFrame(0) // frame 0 is the top frame.
>+// Usage: codeBlockToken = $vm.codeBlockForFrame() // implies frame 0 i.e. current frame.
> static EncodedJSValue JSC_HOST_CALL functionCodeBlockForFrame(ExecState* exec)
> {
>-    if (exec->argumentCount() < 1)
>-        return JSValue::encode(jsUndefined());
>-
>-    JSValue value = exec->uncheckedArgument(0);
>-    if (!value.isUInt32())
>-        return JSValue::encode(jsUndefined());
>+    unsigned frameNumber = 1;
>+    if (exec->argumentCount() >= 1) {
>+        JSValue value = exec->uncheckedArgument(0);
>+        if (!value.isUInt32())
>+            return JSValue::encode(jsUndefined());
>+
>+        // We need to inc the frame number because the caller would consider
>+        // its own frame as frame 0. Hence, we need discount the frame for this
>+        // function.
>+        frameNumber = value.asUInt32() + 1;
>+    }
> 
>-    // We need to inc the frame number because the caller would consider
>-    // its own frame as frame 0. Hence, we need discount the frame for this
>-    // function.
>-    unsigned frameNumber = value.asUInt32() + 1;
>     CodeBlock* codeBlock = VMInspector::codeBlockForFrame(exec, frameNumber);
>-    // Though CodeBlock is a JSCell, it is not safe to return it directly back to JS code
>-    // as it is an internal type that the JS code cannot handle. Hence, we first encode the
>-    // CodeBlock* as a double token (which is safe for JS code to handle) before returning it.
>-    return JSValue::encode(JSValue(bitwise_cast<double>(static_cast<uint64_t>(reinterpret_cast<uintptr_t>(codeBlock)))));
>+    return JSValue::encode(codeBlock);
> }
> 
> static CodeBlock* codeBlockFromArg(ExecState* exec)
>@@ -1282,12 +1366,8 @@ static CodeBlock* codeBlockFromArg(ExecS
>                 candidateCodeBlock = nullptr;
>             else
>                 candidateCodeBlock = func->jsExecutable()->eitherCodeBlock();
>-        }
>-    } else if (value.isDouble()) {
>-        // If the value is a double, it may be an encoded CodeBlock* that came from
>-        // $vm.codeBlockForFrame(). We'll treat it as a candidate codeBlock and check if it's
>-        // valid below before using.
>-        candidateCodeBlock = reinterpret_cast<CodeBlock*>(bitwise_cast<uint64_t>(value.asDouble()));
>+        } else
>+            candidateCodeBlock = reinterpret_cast<CodeBlock*>(value.asCell());
>     }
> 
>     if (candidateCodeBlock && VMInspector::isValidCodeBlock(exec, candidateCodeBlock))
>@@ -1333,19 +1413,43 @@ static EncodedJSValue JSC_HOST_CALL func
>     return JSValue::encode(jsUndefined());
> }
> 
>-// Prints a series of comma separate strings without inserting a newline.
>-// Usage: $vm.print(str1, str2, str3)
>-static EncodedJSValue JSC_HOST_CALL functionPrint(ExecState* exec)
>+static EncodedJSValue doPrintln(ExecState* exec, bool addLineFeed)
> {
>     auto scope = DECLARE_THROW_SCOPE(exec->vm());
>     for (unsigned i = 0; i < exec->argumentCount(); ++i) {
>+        JSValue arg = exec->uncheckedArgument(i);
>+        if (arg.isCell()
>+            && !arg.isObject()
>+            && !arg.isString()
>+            && !arg.isBigInt()) {
>+            dataLog(arg);
>+            continue;
>+        }
>         String argStr = exec->uncheckedArgument(i).toWTFString(exec);
>         RETURN_IF_EXCEPTION(scope, encodedJSValue());
>         dataLog(argStr);
>     }
>+    if (addLineFeed)
>+        dataLog("\n");
>     return JSValue::encode(jsUndefined());
> }
> 
>+// Prints a series of comma separate strings without appending a newline.
>+// Usage: $vm.print(str1, str2, str3)
>+static EncodedJSValue JSC_HOST_CALL functionPrint(ExecState* exec)
>+{
>+    const bool addLineFeed = false;
>+    return doPrintln(exec, addLineFeed);
>+}
>+
>+// Prints a series of comma separate strings and appends a newline.
>+// Usage: $vm.println(str1, str2, str3)
>+static EncodedJSValue JSC_HOST_CALL functionPrintln(ExecState* exec)
>+{
>+    const bool addLineFeed = true;
>+    return doPrintln(exec, addLineFeed);
>+}
>+
> // Prints the current CallFrame.
> // Usage: $vm.printCallFrame()
> static EncodedJSValue JSC_HOST_CALL functionPrintCallFrame(ExecState* exec)
>@@ -1717,6 +1821,30 @@ static EncodedJSValue JSC_HOST_CALL func
>     return JSValue::encode(jsUndefined());
> }
> 
>+static EncodedJSValue changeDebuggerModeWhenIdle(ExecState* exec, DebuggerMode mode)
>+{
>+    bool newDebuggerMode = (mode == DebuggerOn);
>+    if (Options::forceDebuggerBytecodeGeneration() == newDebuggerMode)
>+        return JSValue::encode(jsUndefined());
>+
>+    VM* vm = &exec->vm();
>+    vm->whenIdle([=] () {
>+        Options::forceDebuggerBytecodeGeneration() = newDebuggerMode;
>+        vm->deleteAllCode(PreventCollectionAndDeleteAllCode);
>+    });
>+    return JSValue::encode(jsUndefined());
>+}
>+
>+static EncodedJSValue JSC_HOST_CALL functionEnableDebuggerModeWhenIdle(ExecState* exec)
>+{
>+    return changeDebuggerModeWhenIdle(exec, DebuggerOn);
>+}
>+
>+static EncodedJSValue JSC_HOST_CALL functionDisableDebuggerModeWhenIdle(ExecState* exec)
>+{
>+    return changeDebuggerModeWhenIdle(exec, DebuggerOff);
>+}
>+
> static EncodedJSValue JSC_HOST_CALL functionGlobalObjectCount(ExecState* exec)
> {
>     return JSValue::encode(jsNumber(exec->vm().heap.globalObjectCount()));
>@@ -1832,12 +1960,14 @@ void JSDollarVM::finishCreation(VM& vm)
>     addFunction(vm, "gc", functionGC, 0);
>     addFunction(vm, "edenGC", functionEdenGC, 0);
> 
>+    addFunction(vm, "callFrame", functionCallFrame, 1);
>     addFunction(vm, "codeBlockFor", functionCodeBlockFor, 1);
>     addFunction(vm, "codeBlockForFrame", functionCodeBlockForFrame, 1);
>     addFunction(vm, "printSourceFor", functionPrintSourceFor, 1);
>     addFunction(vm, "printBytecodeFor", functionPrintBytecodeFor, 1);
> 
>     addFunction(vm, "print", functionPrint, 1);
>+    addFunction(vm, "println", functionPrintln, 1);
>     addFunction(vm, "printCallFrame", functionPrintCallFrame, 0);
>     addFunction(vm, "printStack", functionPrintStack, 0);
> 
>@@ -1882,6 +2012,9 @@ void JSDollarVM::finishCreation(VM& vm)
> 
>     addFunction(vm, "enableExceptionFuzz", functionEnableExceptionFuzz, 0);
> 
>+    addFunction(vm, "enableDebuggerModeWhenIdle", functionEnableDebuggerModeWhenIdle, 0);
>+    addFunction(vm, "disableDebuggerModeWhenIdle", functionDisableDebuggerModeWhenIdle, 0);
>+
>     addFunction(vm, "globalObjectCount", functionGlobalObjectCount, 0);
>     addFunction(vm, "globalObjectForObject", functionGlobalObjectForObject, 1);
>

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keith_miller: review+

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Attachments on bug 186947: 343406