Visit proxy methods reference arguments when visiting Quick frames roots.

The arguments of a proxy method, stored in the proxy method's stack
frame, need to be visited as GC roots. This is especially important
in the case of a moving GC, where these reference arguments may be
moved like any object. Previously, we would only visit the target
(`this` argument) of proxy methods when visiting Quick frames roots.

Test: art/test/testrunner/testrunner.py --gcstress -t 999-proxy-method-arguments
Test: m test-art-host
Test: m test-art-target
Bug: 73149739
Bug: 70216372
Bug: 67679263
Change-Id: Ieacc966ab1038935600f2193c14e6ca01e88602e
diff --git a/test/1945-proxy-method-arguments/get_args.cc b/test/1945-proxy-method-arguments/get_args.cc
new file mode 100644
index 0000000..211ae10
--- /dev/null
+++ b/test/1945-proxy-method-arguments/get_args.cc
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "arch/context.h"
+#include "art_method-inl.h"
+#include "jni.h"
+#include "oat_quick_method_header.h"
+#include "scoped_thread_state_change-inl.h"
+#include "stack.h"
+#include "thread.h"
+
+namespace art {
+
+namespace {
+
+// Visit a proxy method Quick frame at a given depth.
+class GetProxyQuickFrameVisitor FINAL : public StackVisitor {
+ public:
+  GetProxyQuickFrameVisitor(art::Thread* target, art::Context* ctx, size_t frame_depth)
+      REQUIRES_SHARED(art::Locks::mutator_lock_)
+      : art::StackVisitor(target, ctx, art::StackVisitor::StackWalkKind::kIncludeInlinedFrames),
+        cur_depth_(0u),
+        frame_depth_(frame_depth),
+        quick_frame_(nullptr) {}
+
+  bool VisitFrame() OVERRIDE REQUIRES_SHARED(Locks::mutator_lock_) {
+    if (GetMethod()->IsRuntimeMethod()) {
+      return true;
+    }
+    if (cur_depth_ == frame_depth_) {
+      // Found frame.
+      ShadowFrame* shadow_frame = GetCurrentShadowFrame();
+      if (shadow_frame != nullptr) {
+        // Nothing to do.
+      } else {
+        VisitQuickFrameAtSearchedDepth();
+      }
+      return false;
+    } else {
+      ++cur_depth_;
+      return true;
+    }
+  }
+
+  void VisitQuickFrameAtSearchedDepth() REQUIRES_SHARED(Locks::mutator_lock_) {
+    quick_frame_ = GetCurrentQuickFrame();
+    CHECK(quick_frame_ != nullptr);
+    ArtMethod* method = *quick_frame_;
+    CHECK(method != nullptr);
+    CHECK(method->IsProxyMethod()) << method->PrettyMethod();
+  }
+
+  // Return the found Quick frame.
+  ArtMethod** GetQuickFrame() {
+    return quick_frame_;
+  }
+
+ private:
+  // The depth of the currently visited frame.
+  size_t cur_depth_;
+  // The depth of the currently searched frame.
+  size_t frame_depth_;
+  // The quick frame, if found.
+  ArtMethod** quick_frame_;
+  // Method name
+
+  DISALLOW_COPY_AND_ASSIGN(GetProxyQuickFrameVisitor);
+};
+
+extern "C" StackReference<mirror::Object>* artQuickGetProxyReferenceArgumentAt(size_t arg_pos,
+                                                                               ArtMethod** sp)
+    REQUIRES_SHARED(Locks::mutator_lock_);
+
+jobject GetProxyReferenceArgument(size_t arg_pos, size_t proxy_method_frame_depth) {
+  Thread* self = Thread::Current();
+  ScopedObjectAccess soa(self);
+  std::unique_ptr<Context> context(Context::Create());
+
+  GetProxyQuickFrameVisitor visitor(self, context.get(), proxy_method_frame_depth);
+  visitor.WalkStack();
+  ArtMethod** quick_frame = visitor.GetQuickFrame();
+  CHECK(quick_frame != nullptr);
+
+  // Find reference argument in frame.
+  StackReference<mirror::Object>* ref_arg =
+      artQuickGetProxyReferenceArgumentAt(arg_pos, quick_frame);
+  CHECK(ref_arg != nullptr);
+  art::ObjPtr<mirror::Object> obj = ref_arg->AsMirrorPtr();
+
+  return obj.IsNull() ? nullptr : soa.AddLocalReference<jobject>(obj);
+}
+
+extern "C" JNIEXPORT jobject JNICALL Java_TestInvocationHandler_getArgument(
+    JNIEnv* env ATTRIBUTE_UNUSED, jobject thiz ATTRIBUTE_UNUSED, int arg_pos, int frame_depth) {
+  return GetProxyReferenceArgument(arg_pos, frame_depth);
+}
+
+}  // namespace
+
+}  // namespace art