[JSC] Add dumpAndClearSamplingProfilerSamples function

https://bugs.webkit.org/show_bug.cgi?id=259411
rdar://112686960

Reviewed by Justin Michaud.

This patch adds dumpAndClearSamplingProfilerSamples behind a flag, which dumps sampling profiler data into temp file.
This allows us to automated sampling data collection for benchmarks by calling this function at the right timing.
We also significantly expand the JSON data generation of SamplingProfiler to reconstruct enough information from this output.

We also attach display-sampling-profiler-output script as the same to display-profiler-output. Which can feed the above JSON
and dump sampling profiler output.

* Source/JavaScriptCore/runtime/JSGlobalObject.cpp:
(JSC::JSC_DEFINE_HOST_FUNCTION):
(JSC::JSGlobalObject::init):
* Source/JavaScriptCore/runtime/VM.cpp:
(JSC::VM::enableSamplingProfiler):
(JSC::VM::disableSamplingProfiler):
(JSC::VM::takeSamplingProfilerSamplesAsJSONString):
* Source/JavaScriptCore/runtime/VM.h:

Canonical link: https://commits.webkit.org/266270@main

JSTests/stress/sampling-profiler-anonymous-function.js

@@ -18,5 +18,5 @@ if (platformSupportsSamplingProfiler()) {
         });
     }
 
-    runTest(baz, ["(anonymous function)", "foo", "baz"]);
+    runTest(baz, ["", "foo", "baz"]);
 }

JSTests/stress/sampling-profiler-stack-trace-with-double-quote-in-function-name.js

@@ -11,7 +11,7 @@ if (platformSupportsSamplingProfiler()) {
         for (let i = 0; i < 1000; ++i) {
             foo();
             let stacktraces = samplingProfilerStackTraces();
-            for (let stackTrace of stacktraces) { }
+            for (let stackTrace of stacktraces.traces) { }
         }
     }
 

JSTests/stress/sampling-profiler/samplingProfiler.js

@@ -25,10 +25,10 @@ function makeNode(name) {
 
 function updateCallingContextTree(root) {
     let stacktraces = samplingProfilerStackTraces();
-    for (let stackTrace of stacktraces) {
+    for (let stackTrace of stacktraces.traces) {
         let node = root;
-        for (let i = stackTrace.length; i--; ) {
-            let functionName = stackTrace[i];
+        for (let i = stackTrace.frames.length; i--; ) {
+            let functionName = stackTrace.frames[i].name;
             node = node.makeChildIfNeeded(functionName);
         }
     }

Source/JavaScriptCore/jsc.cpp

@@ -2976,8 +2976,9 @@ JSC_DEFINE_HOST_FUNCTION(functionSamplingProfilerStackTraces, (JSGlobalObject* g
     if (!vm.samplingProfiler())
         return JSValue::encode(throwException(globalObject, scope, createError(globalObject, "Sampling profiler was never started"_s)));
 
-    String jsonString = vm.samplingProfiler()->stackTracesAsJSON();
-    EncodedJSValue result = JSValue::encode(JSONParse(globalObject, jsonString));
+    auto json = vm.samplingProfiler()->stackTracesAsJSON();
+    auto jsonString = json->toJSONString();
+    EncodedJSValue result = JSValue::encode(JSONParse(globalObject, WTFMove(jsonString)));
     scope.releaseAssertNoException();
     return result;
 }

Source/JavaScriptCore/runtime/JSGlobalObject.cpp

@@ -302,6 +302,7 @@ static JSC_DECLARE_HOST_FUNCTION(assertCall);
 #if ENABLE(SAMPLING_PROFILER)
 static JSC_DECLARE_HOST_FUNCTION(enableSamplingProfiler);
 static JSC_DECLARE_HOST_FUNCTION(disableSamplingProfiler);
+static JSC_DECLARE_HOST_FUNCTION(dumpAndClearSamplingProfilerSamples);
 #endif
 
 static JSC_DECLARE_HOST_FUNCTION(tracePointStart);
@@ -405,22 +406,46 @@ JSC_DEFINE_HOST_FUNCTION(assertCall, (JSGlobalObject* globalObject, CallFrame* c
 #if ENABLE(SAMPLING_PROFILER)
 JSC_DEFINE_HOST_FUNCTION(enableSamplingProfiler, (JSGlobalObject* globalObject, CallFrame*))
 {
-    SamplingProfiler* profiler = globalObject->vm().samplingProfiler();
-    if (!profiler)
-        profiler = &globalObject->vm().ensureSamplingProfiler(Stopwatch::create());
-    profiler->start();
+    globalObject->vm().enableSamplingProfiler();
     return JSValue::encode(jsUndefined());
 }
 
 JSC_DEFINE_HOST_FUNCTION(disableSamplingProfiler, (JSGlobalObject* globalObject, CallFrame*))
 {
-    SamplingProfiler* profiler = globalObject->vm().samplingProfiler();
-    if (!profiler)
-        profiler = &globalObject->vm().ensureSamplingProfiler(Stopwatch::create());
+    globalObject->vm().disableSamplingProfiler();
+    return JSValue::encode(jsUndefined());
+}
 
+JSC_DEFINE_HOST_FUNCTION(dumpAndClearSamplingProfilerSamples, (JSGlobalObject* globalObject, CallFrame* callFrame))
+{
+    VM& vm = globalObject->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    JSValue argument = callFrame->argument(0);
+    auto filenamePrefix = emptyString();
+    if (!argument.isUndefinedOrNull()) {
+        filenamePrefix = argument.toWTFString(globalObject);
+        RETURN_IF_EXCEPTION(scope, { });
+    }
+
+    auto json = vm.takeSamplingProfilerSamplesAsJSON();
+    if (UNLIKELY(!json))
+        return JSValue::encode(jsUndefined());
+
+    auto jsonData = json->toJSONString();
     {
-        Locker locker { profiler->getLock() };
-        profiler->pause();
+        FileSystem::PlatformFileHandle fileHandle;
+        String tempFilePath = FileSystem::openTemporaryFile(filenamePrefix, fileHandle);
+        if (!FileSystem::isHandleValid(fileHandle)) {
+            dataLogLn("Dumping sampling profiler samples failed to open temporary file");
+            return JSValue::encode(jsUndefined());
+        }
+
+        CString utf8String = jsonData.utf8();
+
+        FileSystem::writeToFile(fileHandle, utf8String.data(), utf8String.length());
+        FileSystem::closeFile(fileHandle);
+        dataLogLn("Dumped sampling profiler samples to ", tempFilePath);
     }
 
     return JSValue::encode(jsUndefined());
@@ -1659,6 +1684,7 @@ capitalName ## Constructor* lowerName ## Constructor = featureFlag ? capitalName
 #if ENABLE(SAMPLING_PROFILER)
         putDirectWithoutTransition(vm, Identifier::fromString(vm, "__enableSamplingProfiler"_s), JSFunction::create(vm, this, 1, "enableSamplingProfiler"_s, enableSamplingProfiler, ImplementationVisibility::Public), PropertyAttribute::DontEnum | PropertyAttribute::DontDelete | PropertyAttribute::ReadOnly);
         putDirectWithoutTransition(vm, Identifier::fromString(vm, "__disableSamplingProfiler"_s), JSFunction::create(vm, this, 1, "disableSamplingProfiler"_s, disableSamplingProfiler, ImplementationVisibility::Public), PropertyAttribute::DontEnum | PropertyAttribute::DontDelete | PropertyAttribute::ReadOnly);
+        putDirectWithoutTransition(vm, Identifier::fromString(vm, "__dumpAndClearSamplingProfilerSamples"_s), JSFunction::create(vm, this, 1, "dumpAndClearSamplingProfilerSamples"_s, dumpAndClearSamplingProfilerSamples, ImplementationVisibility::Public), PropertyAttribute::DontEnum | PropertyAttribute::DontDelete | PropertyAttribute::ReadOnly);
 #endif
         putDirectWithoutTransition(vm, Identifier::fromString(vm, "__enableSuperSampler"_s), JSFunction::create(vm, this, 1, "enableSuperSampler"_s, enableSuperSampler, ImplementationVisibility::Public), PropertyAttribute::DontEnum | PropertyAttribute::DontDelete | PropertyAttribute::ReadOnly);
         putDirectWithoutTransition(vm, Identifier::fromString(vm, "__disableSuperSampler"_s), JSFunction::create(vm, this, 1, "disableSuperSampler"_s, disableSuperSampler, ImplementationVisibility::Public), PropertyAttribute::DontEnum | PropertyAttribute::DontDelete | PropertyAttribute::ReadOnly);