Bug 959214 - Use unwinder when getting ANR native stack; r=blassey

mobile/android/base/ANRReporter.java

@@ -54,7 +54,7 @@ public final class ANRReporter extends BroadcastReceiver
     private Handler mHandler;
     private volatile boolean mPendingANR;
 
-    private static native boolean requestNativeStack();
+    private static native boolean requestNativeStack(boolean unwind);
     private static native String getNativeStack();
     private static native void releaseNativeStack();
 
@@ -460,7 +460,9 @@ public final class ANRReporter extends BroadcastReceiver
 
     private static void processTraces(Reader traces, File pingFile) {
 
-        boolean haveNativeStack = requestNativeStack();
+        // Unwinding is memory intensive; only unwind if we have enough memory
+        boolean haveNativeStack = requestNativeStack(
+            /* unwind */ SysInfo.getMemSize() >= 640);
         try {
             OutputStream ping = new BufferedOutputStream(
                 new FileOutputStream(pingFile), TRACES_BLOCK_SIZE);

mozglue/android/jni-stubs.inc

@@ -533,16 +533,16 @@ Java_org_mozilla_gecko_gfx_NativePanZoomController_getOverScrollMode(JNIEnv * ar
 
 #ifdef JNI_STUBS
 
-typedef jboolean (*Java_org_mozilla_gecko_ANRReporter_requestNativeStack_t)(JNIEnv *, jclass);
+typedef jboolean (*Java_org_mozilla_gecko_ANRReporter_requestNativeStack_t)(JNIEnv *, jclass, jboolean);
 static Java_org_mozilla_gecko_ANRReporter_requestNativeStack_t f_Java_org_mozilla_gecko_ANRReporter_requestNativeStack;
 extern "C" NS_EXPORT jboolean JNICALL
-Java_org_mozilla_gecko_ANRReporter_requestNativeStack(JNIEnv * arg0, jclass arg1) {
+Java_org_mozilla_gecko_ANRReporter_requestNativeStack(JNIEnv * arg0, jclass arg1, jboolean arg2) {
     if (!f_Java_org_mozilla_gecko_ANRReporter_requestNativeStack) {
         arg0->ThrowNew(arg0->FindClass("java/lang/UnsupportedOperationException"),
                        "JNI Function called before it was loaded");
         return false;
     }
-    return f_Java_org_mozilla_gecko_ANRReporter_requestNativeStack(arg0, arg1);
+    return f_Java_org_mozilla_gecko_ANRReporter_requestNativeStack(arg0, arg1, arg2);
 }
 #endif
 

widget/android/AndroidJNI.cpp

@@ -945,7 +945,7 @@ Java_org_mozilla_gecko_gfx_NativePanZoomController_getOverScrollMode(JNIEnv* env
 }
 
 NS_EXPORT jboolean JNICALL
-Java_org_mozilla_gecko_ANRReporter_requestNativeStack(JNIEnv*, jclass)
+Java_org_mozilla_gecko_ANRReporter_requestNativeStack(JNIEnv*, jclass, jboolean aUnwind)
 {
     if (profiler_is_active()) {
         // Don't proceed if profiler is already running
@@ -955,11 +955,25 @@ Java_org_mozilla_gecko_ANRReporter_requestNativeStack(JNIEnv*, jclass)
     // generally unsafe to use the profiler from off the main thread. However,
     // the risk here is limited because for most users, the profiler is not run
     // elsewhere. See the discussion in Bug 863777, comment 13
-    const char *NATIVE_STACK_FEATURES[] = {"leaf", "threads", "privacy"};
+    const char *NATIVE_STACK_FEATURES[] =
+        {"leaf", "threads", "privacy"};
+    const char *NATIVE_STACK_UNWIND_FEATURES[] =
+        {"leaf", "threads", "privacy", "stackwalk"};
+
+    const char **features = NATIVE_STACK_FEATURES;
+    size_t features_size = sizeof(NATIVE_STACK_FEATURES);
+    if (aUnwind) {
+        features = NATIVE_STACK_UNWIND_FEATURES;
+        features_size = sizeof(NATIVE_STACK_UNWIND_FEATURES);
+        // We want the new unwinder if the unwind mode has not been set yet
+        putenv("MOZ_PROFILER_NEW=1");
+    }
+
+    const char *NATIVE_STACK_THREADS[] =
+        {"GeckoMain", "Compositor"};
     // Buffer one sample and let the profiler wait a long time
-    profiler_start(100, 10000, NATIVE_STACK_FEATURES,
-        sizeof(NATIVE_STACK_FEATURES) / sizeof(char*),
-        nullptr, 0);
+    profiler_start(100, 10000, features, features_size / sizeof(char*),
+        NATIVE_STACK_THREADS, sizeof(NATIVE_STACK_THREADS) / sizeof(char*));
     return JNI_TRUE;
 }