Add support for JSC's sampling profiler on iOS for RN

Reviewed By: javache

Differential Revision: D4107919

fbshipit-source-id: ecfe2cacdb78b857e461f7006b29e4d1fe1a1862

React/Executors/RCTJSCExecutor.mm

@@ -31,6 +31,7 @@
 #import "RCTSourceCode.h"
 #import "RCTJSCWrapper.h"
 #import "RCTJSCErrorHandling.h"
+#import "JSCSamplingProfiler.h"
 
 NSString *const RCTJSCThreadName = @"com.facebook.react.JavaScript";
 NSString *const RCTJavaScriptContextCreatedNotification = @"RCTJavaScriptContextCreatedNotification";
@@ -417,6 +418,36 @@ static NSThread *newJavaScriptThread(void)
         [weakBridge.flowIDMapLock unlock];
       }
     };
+
+    // Add toggles for JSC's sampling profiler, if the profiler is enabled
+    if (self->_jscWrapper->JSSamplingProfilerEnabled()) {
+        // Mark this thread as the main JS thread before starting profiling.
+        self->_jscWrapper->JSStartSamplingProfilingOnMainJSCThread(context.JSGlobalContextRef);
+
+      // Allow to toggle the sampling profiler through RN's dev menu
+      __weak JSContext *weakContext = self->_context.context;
+      [self->_bridge.devMenu addItem:[RCTDevMenuItem buttonItemWithTitle:@"Start / Stop JS Sampling Profiler" handler:^{
+        // JSPokeSamplingProfiler() toggles the profiling process
+        JSValueRef jsResult = self->_jscWrapper->JSPokeSamplingProfiler(weakContext.JSGlobalContextRef);
+
+        if (!self->_jscWrapper->JSValueIsNull(weakContext.JSGlobalContextRef, jsResult)) {
+          NSString *results = [[self->_jscWrapper->JSValue valueWithJSValueRef:jsResult inContext:weakContext] toObject];
+          JSCSamplingProfiler *profilerModule = [self->_bridge moduleForClass:[JSCSamplingProfiler class]];
+          [profilerModule operationCompletedWithResults:results];
+        }
+      }]];
+
+      // Allow for the profiler to be poked from JS code as well
+      // (see SamplingProfiler.js for an example of how it could be used with the JSCSamplingProfiler module).
+      context[@"pokeSamplingProfiler"] = ^(NSDictionary *){
+        RCTJSCExecutor *strongSelf = weakSelf;
+        if (!strongSelf.isValid) {
+          return @{};
+        }
+        JSValueRef result = strongSelf->_jscWrapper->JSPokeSamplingProfiler(weakContext.JSGlobalContextRef);
+        return (NSDictionary *)[[strongSelf->_jscWrapper->JSValue valueWithJSValueRef:result inContext:weakContext] toObject];
+      };
+    }
 #endif
 
 #if RCT_DEV

React/Executors/RCTJSCWrapper.h

@@ -28,13 +28,15 @@ typedef JSStringRef (*JSPropertyNameArrayGetNameAtIndexFuncType)(JSPropertyNameA
 typedef void (*JSPropertyNameArrayReleaseFuncType)(JSPropertyNameArrayRef);
 typedef JSValueRef (*JSValueMakeFromJSONStringFuncType)(JSContextRef, JSStringRef);
 typedef JSValueRef (*JSObjectCallAsFunctionFuncType)(JSContextRef, JSObjectRef, JSObjectRef, size_t, const JSValueRef *, JSValueRef *);
-typedef JSValueRef (*JSValueMakeNullFuncType)(JSContextRef);
+typedef JSValueRef (*JSValueRefWithJSContextRefFuncType)(JSContextRef);
 typedef JSStringRef (*JSValueCreateJSONStringFuncType)(JSContextRef, JSValueRef, unsigned, JSValueRef *);
 typedef bool (*JSValueIsUndefinedFuncType)(JSContextRef, JSValueRef);
 typedef bool (*JSValueIsNullFuncType)(JSContextRef, JSValueRef);
 typedef JSObjectRef (*JSValueToObjectFuncType)(JSContextRef, JSValueRef, JSValueRef *);
 typedef JSValueRef (*JSEvaluateScriptFuncType)(JSContextRef, JSStringRef, JSObjectRef, JSStringRef, int, JSValueRef *);
 typedef JSValueRef (*JSEvaluateBytecodeBundleFuncType)(JSContextRef, JSObjectRef, int, JSStringRef, JSValueRef *);
+typedef bool (*JSSamplingProfilerEnabledFuncType)();
+typedef void (*JSStartSamplingProfilingOnMainJSCThreadFuncType)(JSGlobalContextRef);
 
 /**
  * JSNoBytecodeFileFormatVersion
@@ -60,7 +62,7 @@ typedef struct RCTJSCWrapper {
   JSPropertyNameArrayReleaseFuncType JSPropertyNameArrayRelease;
   JSValueMakeFromJSONStringFuncType JSValueMakeFromJSONString;
   JSObjectCallAsFunctionFuncType JSObjectCallAsFunction;
-  JSValueMakeNullFuncType JSValueMakeNull;
+  JSValueRefWithJSContextRefFuncType JSValueMakeNull;
   JSValueCreateJSONStringFuncType JSValueCreateJSONString;
   JSValueIsUndefinedFuncType JSValueIsUndefined;
   JSValueIsNullFuncType JSValueIsNull;
@@ -68,6 +70,9 @@ typedef struct RCTJSCWrapper {
   JSEvaluateScriptFuncType JSEvaluateScript;
   JSEvaluateBytecodeBundleFuncType JSEvaluateBytecodeBundle;
   voidWithNoParamsFuncType configureJSCForIOS;
+  JSSamplingProfilerEnabledFuncType JSSamplingProfilerEnabled;
+  JSValueRefWithJSContextRefFuncType JSPokeSamplingProfiler;
+  JSStartSamplingProfilingOnMainJSCThreadFuncType JSStartSamplingProfilingOnMainJSCThread;
   const int32_t JSBytecodeFileFormatVersion;
   Class JSContext;
   Class JSValue;

React/Executors/RCTJSCWrapper.mm

@@ -24,12 +24,15 @@ assert(false);\
 }
 
 UNIMPLEMENTED_SYSTEM_JSC_FUNCTION(JSEvaluateBytecodeBundle)
+UNIMPLEMENTED_SYSTEM_JSC_FUNCTION(JSPokeSamplingProfiler)
+UNIMPLEMENTED_SYSTEM_JSC_FUNCTION(JSStartSamplingProfilingOnMainJSCThread)
 
 #undef UNIMPLEMENTED_SYSTEM_JSC_FUNCTION
 
 // A no-op function, to replace void functions that do no exist in the system JSC
 //  with a function that does nothing.
 static void noOpSystemJSCFunc(void *args...){ }
+static bool alwaysFalseSystemJSCFunc(void *args...){ return false; }
 
 void __attribute__((visibility("hidden"),weak)) RCTCustomJSCInit(__unused void *handle) {
   return;
@@ -85,6 +88,9 @@ static RCTJSCWrapper *RCTSetUpSystemLibraryPointers()
     .JSBytecodeFileFormatVersion = JSNoBytecodeFileFormatVersion,
     .JSEvaluateBytecodeBundle = (JSEvaluateBytecodeBundleFuncType)UnimplementedJSEvaluateBytecodeBundle,
     .configureJSCForIOS = (voidWithNoParamsFuncType)noOpSystemJSCFunc,
+    .JSSamplingProfilerEnabled = (JSSamplingProfilerEnabledFuncType)alwaysFalseSystemJSCFunc,
+    .JSPokeSamplingProfiler = (JSValueRefWithJSContextRefFuncType)UnimplementedJSPokeSamplingProfiler,
+    .JSStartSamplingProfilingOnMainJSCThread = (JSStartSamplingProfilingOnMainJSCThreadFuncType)UnimplementedJSStartSamplingProfilingOnMainJSCThread,
     .JSContext = [JSContext class],
     .JSValue = [JSValue class],
   };
@@ -114,7 +120,7 @@ static RCTJSCWrapper *RCTSetUpCustomLibraryPointers()
     .JSPropertyNameArrayRelease = (JSPropertyNameArrayReleaseFuncType)dlsym(libraryHandle, "JSPropertyNameArrayRelease"),
     .JSValueMakeFromJSONString = (JSValueMakeFromJSONStringFuncType)dlsym(libraryHandle, "JSValueMakeFromJSONString"),
     .JSObjectCallAsFunction = (JSObjectCallAsFunctionFuncType)dlsym(libraryHandle, "JSObjectCallAsFunction"),
-    .JSValueMakeNull = (JSValueMakeNullFuncType)dlsym(libraryHandle, "JSValueMakeNull"),
+    .JSValueMakeNull = (JSValueRefWithJSContextRefFuncType)dlsym(libraryHandle, "JSValueMakeNull"),
     .JSValueCreateJSONString = (JSValueCreateJSONStringFuncType)dlsym(libraryHandle, "JSValueCreateJSONString"),
     .JSValueIsUndefined = (JSValueIsUndefinedFuncType)dlsym(libraryHandle, "JSValueIsUndefined"),
     .JSValueIsNull = (JSValueIsNullFuncType)dlsym(libraryHandle, "JSValueIsNull"),
@@ -122,6 +128,9 @@ static RCTJSCWrapper *RCTSetUpCustomLibraryPointers()
     .JSEvaluateScript = (JSEvaluateScriptFuncType)dlsym(libraryHandle, "JSEvaluateScript"),
     .JSEvaluateBytecodeBundle = (JSEvaluateBytecodeBundleFuncType)dlsym(libraryHandle, "JSEvaluateBytecodeBundle"),
     .configureJSCForIOS = (voidWithNoParamsFuncType)dlsym(libraryHandle, "configureJSCForIOS"),
+    .JSSamplingProfilerEnabled = (JSSamplingProfilerEnabledFuncType)dlsym(libraryHandle, "JSSamplingProfilerEnabled"),
+    .JSPokeSamplingProfiler = (JSValueRefWithJSContextRefFuncType)dlsym(libraryHandle, "JSPokeSamplingProfiler"),
+    .JSStartSamplingProfilingOnMainJSCThread = (JSStartSamplingProfilingOnMainJSCThreadFuncType)dlsym(libraryHandle, "JSStartSamplingProfilingOnMainJSCThread"),
     .JSBytecodeFileFormatVersion = *(const int32_t *)dlsym(libraryHandle, "JSBytecodeFileFormatVersion"),
     .JSContext = (__bridge Class)dlsym(libraryHandle, "OBJC_CLASS_$_JSContext"),
     .JSValue = (__bridge Class)dlsym(libraryHandle, "OBJC_CLASS_$_JSValue"),

React/Modules/JSCSamplingProfiler.h

@@ -0,0 +1,23 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <Foundation/Foundation.h>
+
+#import "RCTBridgeModule.h"
+
+@interface JSCSamplingProfiler : NSObject <RCTBridgeModule>
+
+/**
+ * Receives a JSON string containing the result of a JSC CPU Profiling run,
+ *  and sends them to the packager to be symbolicated and saved to disk.
+ * It is safe to call this method from any thread.
+ */
+- (void)operationCompletedWithResults:(NSString *)results;
+
+@end

React/Modules/JSCSamplingProfiler.m

@@ -0,0 +1,58 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "JSCSamplingProfiler.h"
+
+#import "RCTBridge.h"
+#import "RCTLog.h"
+
+@implementation JSCSamplingProfiler
+
+@synthesize methodQueue = _methodQueue;
+@synthesize bridge = _bridge;
+
+RCT_EXPORT_MODULE(JSCSamplingProfiler);
+
+#ifdef RCT_PROFILE
+RCT_EXPORT_METHOD(operationComplete:(int)token result:(id)profileData error:(id)error)
+{
+  if (error) {
+    RCTLogError(@"JSC Sampling profiler ended with error: %@", error);
+    return;
+  }
+
+  // Create a POST request with all of the datas
+  NSURL *url = [NSURL URLWithString:@"/jsc-profile" relativeToURL:self.bridge.bundleURL];
+  NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url
+                                                         cachePolicy:NSURLRequestReloadIgnoringLocalAndRemoteCacheData
+                                                     timeoutInterval:60];
+  [request setHTTPMethod:@"POST"];
+  [request setHTTPBody:[profileData dataUsingEncoding:NSUTF8StringEncoding]];
+
+  // Send the request
+  NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:nil];
+
+  if (connection) {
+    RCTLogInfo(@"JSC CPU Profile data sent successfully.");
+  } else {
+    RCTLogWarn(@"JSC CPU Profile data failed to send.")
+  }
+}
+
+- (void)operationCompletedWithResults:(NSString *)results
+{
+  // Send the results to the packager, using the module's queue.
+  dispatch_async(self.methodQueue, ^{
+    [self operationComplete:0 result:results error:nil];
+  });
+}
+
+#endif
+
+@end