[master] Add nativeZygoteJitEnabled

... to allow the zygote to check whether it needs to keep the jit thread
around.

Bug: 159631815
Bug: 174211442
Test: Boot AOSP
Change-Id: I4d32aee36993cf063d2464d839f2cabda1ee8ff5

3 files changed, 18 insertions, 1 deletions

diff --git a/runtime/jit/jit.cc b/runtime/jit/jit.cc
index 8d434b8a0c..0610f6d073 100644
--- a/runtime/jit/jit.cc
+++ b/runtime/jit/jit.cc
@@ -1193,6 +1193,11 @@ static bool HasImageWithProfile() {
   return false;
 }
 
+bool Jit::InZygoteUsingJit() {
+  Runtime* runtime = Runtime::Current();
+  return runtime->IsZygote() && HasImageWithProfile() && runtime->UseJitCompilation();
+}
+
 void Jit::CreateThreadPool() {
   // There is a DCHECK in the 'AddSamples' method to ensure the tread pool
   // is not null when we instrument.
@@ -1222,7 +1227,7 @@ void Jit::CreateThreadPool() {
     thread_pool_->AddTask(Thread::Current(), new ZygoteVerificationTask());
   }
 
-  if (runtime->IsZygote() && HasImageWithProfile() && UseJitCompilation()) {
+  if (InZygoteUsingJit()) {
     // If we have an image with a profile, request a JIT task to
     // compile all methods in that profile.
     thread_pool_->AddTask(Thread::Current(), new ZygoteTask());
diff --git a/runtime/jit/jit.h b/runtime/jit/jit.h
index e9fd915fc1..40a6eb7c74 100644
--- a/runtime/jit/jit.h
+++ b/runtime/jit/jit.h
@@ -393,6 +393,9 @@ class Jit {
   // Called when system finishes booting.
   void BootCompleted();
 
+  // Are we in a zygote using JIT compilation?
+  static bool InZygoteUsingJit();
+
   // Compile methods from the given profile (.prof extension). If `add_to_queue`
   // is true, methods in the profile are added to the JIT queue. Otherwise they are compiled
   // directly.
diff --git a/runtime/native/dalvik_system_ZygoteHooks.cc b/runtime/native/dalvik_system_ZygoteHooks.cc
index c37b8bb51c..bc19503232 100644
--- a/runtime/native/dalvik_system_ZygoteHooks.cc
+++ b/runtime/native/dalvik_system_ZygoteHooks.cc
@@ -434,11 +434,20 @@ static void ZygoteHooks_stopZygoteNoThreadCreation(JNIEnv* env ATTRIBUTE_UNUSED,
   Runtime::Current()->SetZygoteNoThreadSection(false);
 }
 
+static jboolean ZygoteHooks_nativeZygoteJitEnabled(JNIEnv* env ATTRIBUTE_UNUSED,
+                                                   jclass klass ATTRIBUTE_UNUSED) {
+  // Only called in zygote. Thus static is OK here.
+  static bool result = jit::Jit::InZygoteUsingJit();
+  return result ? JNI_TRUE : JNI_FALSE;
+}
+
+
 static JNINativeMethod gMethods[] = {
   NATIVE_METHOD(ZygoteHooks, nativePreFork, "()J"),
   NATIVE_METHOD(ZygoteHooks, nativePostZygoteFork, "()V"),
   NATIVE_METHOD(ZygoteHooks, nativePostForkSystemServer, "(I)V"),
   NATIVE_METHOD(ZygoteHooks, nativePostForkChild, "(JIZZLjava/lang/String;)V"),
+  NATIVE_METHOD(ZygoteHooks, nativeZygoteJitEnabled, "()Z"),
   NATIVE_METHOD(ZygoteHooks, startZygoteNoThreadCreation, "()V"),
   NATIVE_METHOD(ZygoteHooks, stopZygoteNoThreadCreation, "()V"),
 };