ART: Add allocation tracking to JNI global refs

Add allocation tracking to global references. When the reference
table's free capacity falls under an adjustable value, enable
tracking so as to help tracking down possibly-leaky allocations.

Bug: 67044702
Test: m test-art-host
Change-Id: Ic17d6ebbad895b54c5ac63558027e04aef2b14c1
diff --git a/runtime/java_vm_ext_test.cc b/runtime/java_vm_ext_test.cc
index 2cbfa81..5db493b 100644
--- a/runtime/java_vm_ext_test.cc
+++ b/runtime/java_vm_ext_test.cc
@@ -19,6 +19,7 @@
 #include <pthread.h>
 
 #include "common_runtime_test.h"
+#include "gc/heap.h"
 #include "java_vm_ext.h"
 #include "runtime.h"
 
@@ -134,4 +135,36 @@
   EXPECT_EQ(JNI_ERR, err);
 }
 
+class JavaVmExtStackTraceTest : public JavaVmExtTest {
+ protected:
+  void SetUpRuntimeOptions(RuntimeOptions* options) OVERRIDE {
+    options->emplace_back("-XX:GlobalRefAllocStackTraceLimit=50000", nullptr);
+  }
+};
+
+TEST_F(JavaVmExtStackTraceTest, TestEnableDisable) {
+  ASSERT_FALSE(Runtime::Current()->GetHeap()->IsAllocTrackingEnabled());
+
+  JNIEnv* env;
+  jint ok = vm_->AttachCurrentThread(&env, nullptr);
+  ASSERT_EQ(JNI_OK, ok);
+
+  std::vector<jobject> global_refs_;
+  jobject local_ref = env->NewStringUTF("Dummy");
+  for (size_t i = 0; i < 2000; ++i) {
+    global_refs_.push_back(env->NewGlobalRef(local_ref));
+  }
+
+  EXPECT_TRUE(Runtime::Current()->GetHeap()->IsAllocTrackingEnabled());
+
+  for (jobject global_ref : global_refs_) {
+    env->DeleteGlobalRef(global_ref);
+  }
+
+  EXPECT_FALSE(Runtime::Current()->GetHeap()->IsAllocTrackingEnabled());
+
+  ok = vm_->DetachCurrentThread();
+  EXPECT_EQ(JNI_OK, ok);
+}
+
 }  // namespace art