Introduce JSC profiler API

Summary:
Extract JSC profiler API which can now be used even if profiler is unavailable.

public

Reviewed By: tadeuzagallo

Differential Revision: D2749217

fb-gh-sync-id: 1ffa6f37323ea0ddbda3fdacfdf8a9b360185b2e

React/Executors/RCTContextExecutor.m

@@ -21,25 +21,10 @@
 #import "RCTProfile.h"
 #import "RCTPerformanceLogger.h"
 #import "RCTUtils.h"
-
+#import "RCTJSCProfiler.h"
-#ifndef RCT_JSC_PROFILER
-#if RCT_DEV
-#define RCT_JSC_PROFILER 1
-#else
-#define RCT_JSC_PROFILER 0
-#endif
-#endif
-
-#if RCT_JSC_PROFILER
-#include <dlfcn.h>
 
 static NSString *const RCTJSCProfilerEnabledDefaultsKey = @"RCTJSCProfilerEnabled";
 
-#ifndef RCT_JSC_PROFILER_DYLIB
-#define RCT_JSC_PROFILER_DYLIB [[[NSBundle mainBundle] pathForResource:[NSString stringWithFormat:@"RCTJSCProfiler.ios%zd", [[[UIDevice currentDevice] systemVersion] integerValue]] ofType:@"dylib" inDirectory:@"RCTJSCProfiler"] UTF8String]
-#endif
-#endif
-
 @interface RCTJavaScriptContext : NSObject <RCTInvalidating>
 
 @property (nonatomic, strong, readonly) JSContext *context;
@@ -219,51 +204,19 @@ static JSValueRef RCTNativeTraceEndSection(JSContextRef context, __unused JSObje
 
 static void RCTInstallJSCProfiler(RCTBridge *bridge, JSContextRef context)
 {
-#if RCT_JSC_PROFILER
+  if (RCTJSCProfilerIsSupported()) {
-  void *JSCProfiler = dlopen(RCT_JSC_PROFILER_DYLIB, RTLD_NOW);
-  if (JSCProfiler != NULL) {
-    void (*nativeProfilerStart)(JSContextRef, const char *) =
-      (__typeof__(nativeProfilerStart))dlsym(JSCProfiler, "nativeProfilerStart");
-    void (*nativeProfilerEnd)(JSContextRef, const char *, const char *) =
-      (__typeof__(nativeProfilerEnd))dlsym(JSCProfiler, "nativeProfilerEnd");
-
-    if (nativeProfilerStart != NULL && nativeProfilerEnd != NULL) {
-      void (*nativeProfilerEnableBytecode)(void) =
-        (__typeof__(nativeProfilerEnableBytecode))dlsym(JSCProfiler, "nativeProfilerEnableBytecode");
-
-      if (nativeProfilerEnableBytecode != NULL) {
-        nativeProfilerEnableBytecode();
-      }
-
-      static BOOL isProfiling = NO;
-
-      if (isProfiling) {
-        nativeProfilerStart(context, "profile");
-      }
-
     [bridge.devMenu addItem:[RCTDevMenuItem toggleItemWithKey:RCTJSCProfilerEnabledDefaultsKey title:@"Start Profiling" selectedTitle:@"Stop Profiling" handler:^(BOOL shouldStart) {
-
+      if (shouldStart != RCTJSCProfilerIsProfiling(context)) {
-        if (shouldStart == isProfiling) {
-          return;
-        }
-
-        isProfiling = shouldStart;
-
         if (shouldStart) {
-          nativeProfilerStart(context, "profile");
+          RCTJSCProfilerStart(context);
         } else {
-          NSString *outputFile = [NSTemporaryDirectory() stringByAppendingPathComponent:@"cpu_profile.json"];
+          NSString *outputFile = RCTJSCProfilerStop(context);
-          nativeProfilerEnd(context, "profile", outputFile.UTF8String);
+          NSData *profileData = [NSData dataWithContentsOfFile:outputFile options:NSDataReadingMappedIfSafe error:NULL];
-          NSData *profileData = [NSData dataWithContentsOfFile:outputFile
-                                                       options:NSDataReadingMappedIfSafe
-                                                         error:NULL];
-
           RCTProfileSendResult(bridge, @"cpu-profile", profileData);
         }
+      }
     }]];
   }
-  }
-#endif
 }
 
 #endif

React/Profiler/RCTJSCProfiler.h

@@ -0,0 +1,22 @@
+/**
+ * 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 <JavaScriptCore/JavaScriptCore.h>
+
+#import "RCTDefines.h"
+
+/** The API is not thread-safe. */
+
+/** The context is not retained. */
+RCT_EXTERN void RCTJSCProfilerStart(JSContextRef ctx);
+/** Returns a file path containing the profiler data. */
+RCT_EXTERN NSString *RCTJSCProfilerStop(JSContextRef ctx);
+
+RCT_EXTERN BOOL RCTJSCProfilerIsProfiling(JSContextRef ctx);
+RCT_EXTERN BOOL RCTJSCProfilerIsSupported(void);

React/Profiler/RCTJSCProfiler.m

@@ -0,0 +1,137 @@
+/**
+ * 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 "RCTJSCProfiler.h"
+#import "RCTLog.h"
+#import <UIKit/UIKit.h>
+
+#ifndef RCT_JSC_PROFILER
+  #if RCT_DEV
+    #define RCT_JSC_PROFILER 1
+  #else
+    #define RCT_JSC_PROFILER 0
+  #endif
+#endif
+
+#if RCT_JSC_PROFILER
+
+#include <dlfcn.h>
+
+#ifndef RCT_JSC_PROFILER_DYLIB
+  #define RCT_JSC_PROFILER_DYLIB [[[NSBundle mainBundle] pathForResource:[NSString stringWithFormat:@"RCTJSCProfiler.ios%zd", [[[UIDevice currentDevice] systemVersion] integerValue]] ofType:@"dylib" inDirectory:@"RCTJSCProfiler"] UTF8String]
+#endif
+
+static const char *const JSCProfileName = "profile";
+
+typedef void (*JSCProfilerStartFunctionType)(JSContextRef, const char *);
+typedef void (*JSCProfilerEndFunctionType)(JSContextRef, const char *, const char *);
+typedef void (*JSCProfilerEnableFunctionType)(void);
+
+static NSMutableDictionary<NSValue *, NSNumber *> *RCTJSCProfilerStateMap;
+
+static JSCProfilerStartFunctionType RCTNativeProfilerStart  = NULL;
+static JSCProfilerEndFunctionType RCTNativeProfilerEnd    = NULL;
+
+NS_INLINE NSValue *RCTJSContextRefKey(JSContextRef ref) {
+  return [NSValue valueWithPointer:ref];
+}
+
+static void RCTJSCProfilerStateInit()
+{
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    RCTJSCProfilerStateMap = [NSMutableDictionary new];
+
+    void *JSCProfiler = dlopen(RCT_JSC_PROFILER_DYLIB, RTLD_NOW);
+
+    RCTNativeProfilerStart = (JSCProfilerStartFunctionType)dlsym(JSCProfiler, "nativeProfilerStart");
+    RCTNativeProfilerEnd =  (JSCProfilerEndFunctionType)dlsym(JSCProfiler, "nativeProfilerEnd");
+    JSCProfilerEnableFunctionType enableBytecode = (__typeof__(enableBytecode))dlsym(JSCProfiler, "nativeProfilerEnableBytecode");
+
+    if (RCTNativeProfilerStart && RCTNativeProfilerEnd && enableBytecode) {
+      enableBytecode();
+      RCTLogInfo(@"JSC profiler is available.");
+    } else {
+      RCTNativeProfilerStart = NULL;
+      RCTNativeProfilerEnd = NULL;
+      RCTLogInfo(@"JSC profiler is not supported.");
+    }
+  });
+}
+
+#endif
+
+void RCTJSCProfilerStart(JSContextRef ctx)
+{
+#if RCT_JSC_PROFILER
+  if (ctx != NULL) {
+    if (RCTJSCProfilerIsSupported()) {
+      NSValue *key = RCTJSContextRefKey(ctx);
+      BOOL isProfiling = [RCTJSCProfilerStateMap[key] boolValue];
+      if (!isProfiling) {
+        RCTLogInfo(@"Starting JSC profiler for context: %p", ctx);
+        RCTJSCProfilerStateMap[key] = @YES;
+        RCTNativeProfilerStart(ctx, JSCProfileName);
+      } else {
+        RCTLogWarn(@"Trying to start JSC profiler on a context which is already profiled.");
+      }
+    } else {
+      RCTLogWarn(@"Cannot start JSC profiler as it's not supported.");
+    }
+  } else {
+    RCTLogWarn(@"Trying to start JSC profiler for NULL context.");
+  }
+#endif
+}
+
+NSString *RCTJSCProfilerStop(JSContextRef ctx)
+{
+  NSString *outputFile = nil;
+#if RCT_JSC_PROFILER
+  if (ctx != NULL) {
+    RCTJSCProfilerStateInit();
+    NSValue *key = RCTJSContextRefKey(ctx);
+    BOOL isProfiling = [RCTJSCProfilerStateMap[key] boolValue];
+    if (isProfiling) {
+      NSString *filename = [NSString stringWithFormat:@"cpu_profile_%ld.json", (long)CFAbsoluteTimeGetCurrent()];
+      outputFile = [NSTemporaryDirectory() stringByAppendingPathComponent:filename];
+      RCTNativeProfilerEnd(ctx, JSCProfileName, outputFile.UTF8String);
+      RCTLogInfo(@"Stopped JSC profiler for context: %p", ctx);
+    } else {
+      RCTLogWarn(@"Trying to stop JSC profiler on a context which is not being profiled.");
+    }
+    [RCTJSCProfilerStateMap removeObjectForKey:key];
+  } else {
+    RCTLogWarn(@"Trying to stop JSC profiler for NULL context.");
+  }
+#endif
+  return outputFile;
+}
+
+BOOL RCTJSCProfilerIsProfiling(JSContextRef ctx)
+{
+  BOOL isProfiling = NO;
+#if RCT_JSC_PROFILER
+  if (ctx != NULL) {
+    RCTJSCProfilerStateInit();
+    isProfiling = [RCTJSCProfilerStateMap[RCTJSContextRefKey(ctx)] boolValue];
+  }
+#endif
+  return isProfiling;
+}
+
+BOOL RCTJSCProfilerIsSupported(void)
+{
+  BOOL isSupported = NO;
+#if RCT_JSC_PROFILER
+  RCTJSCProfilerStateInit();
+  isSupported = (RCTNativeProfilerStart != NULL);
+#endif
+  return isSupported;
+}