Fix profiler setup

Summary: @​public

Update packager entry and profiler pre-built dylib +
Update makefile to make it easier to use different versions of Xcode
and shortcircuit when using the wrong version.

Reviewed By: @jspahrsummers

Differential Revision: D2498157

JSCLegacyProfiler/Makefile

@@ -1,6 +1,7 @@
 HEADER_PATHS := `find download/JavaScriptCore -name '*.h' | xargs -I{} dirname {} | uniq | xargs -I{} echo "-I {}"`
 
-SDK_PATH = /Applications/Xcode.app/Contents/Developer/Platforms/$1.platform/Developer/SDKs/$1.sdk
+XCODE_PATH ?= $(shell xcode-select -p)
+SDK_PATH = $(XCODE_PATH)/Platforms/$1.platform/Developer/SDKs/$1.sdk
 
 SDK_VERSION = $(shell plutil -convert json -o - $(call SDK_PATH,iPhoneOS)/SDKSettings.plist | awk -f parseSDKVersion.awk)
 
@@ -19,13 +20,14 @@ SYSROOT = -isysroot $(call SDK_PATH,$${PLATFORM})
 
 IOS8_LIBS = download/WebCore/WebCore-7600.1.25 download/WTF/WTF-7600.1.24 download/JavaScriptCore/JavaScriptCore-7600.1.17 download/JavaScriptCore/JavaScriptCore-7600.1.17/Bytecodes.h
 
-ios8: RCTJSCProfiler.ios8.dylib /tmp/RCTJSCProfiler
 ifneq ($(SDK_VERSION), 8)
+all:
 	$(error "Expected to be compiled with iOS SDK version 8, found $(SDK_VERSION)")
-else
-	cp $^
 endif
 
+ios8: RCTJSCProfiler.ios8.dylib /tmp/RCTJSCProfiler
+	cp $^
+
 /tmp/RCTJSCProfiler:
 	mkdir -p $@
 

packager/packager.js

@@ -233,14 +233,14 @@ function systraceProfileMiddleware(req, res, next) {
   childProcess.exec(cmd, function(error) {
     if (error) {
       if (error.code === 127) {
-        res.end(
-          '\n** Failed executing `' + cmd + '` **\n\n' +
+        var response = '\n** Failed executing `' + cmd + '` **\n\n' +
           'Google trace-viewer is required to visualize the data, You can install it with `brew install trace2html`\n\n' +
           'NOTE: Your profile data was kept at:\n' + dumpName
-        );
+        console.log(response);
+        res.end(response);
       } else {
         console.error(error);
-        res.end('Unknown error %s', error.message);
+        res.end('Unknown error: ' + error.message);
       }
       return;
     } else {
@@ -267,16 +267,16 @@ function cpuProfileMiddleware(req, res, next) {
   var dumpName = '/tmp/cpu-profile_' + Date.now();
   fs.writeFileSync(dumpName + '.json', req.rawBody);
 
-  var cmd = path.join(__dirname, '..', 'JSCLegacyProfiler', 'json2trace') + ' -cpuprofiler ' + dumpName + '.cpuprofile ' + dumpName + '.json';
+  var cmd = path.join(__dirname, '..', 'react-native-github', 'JSCLegacyProfiler', 'json2trace') + ' -cpuprofiler ' + dumpName + '.cpuprofile ' + dumpName + '.json';
   childProcess.exec(cmd, function(error) {
     if (error) {
       console.error(error);
-      res.end('Unknown error: %s', error.message);
+      res.end('Unknown error: ' + error.message);
     } else {
-      res.end(
-        'Your profile was generated at\n\n' + dumpName + '.cpuprofile\n\n' +
-        'Open `Chrome Dev Tools > Profiles > Load` and select the profile to visualize it.'
-      );
+      var response = 'Your profile was generated at\n\n' + dumpName + '.cpuprofile\n\n' +
+        'Open `Chrome Dev Tools > Profiles > Load` and select the profile to visualize it.';
+      console.log(response);
+      res.end(response);
     }
   });
 }