commit a2c97a94ee9379b23204bfef87afacd4b60cae37
author buzbee <buzbee@google.com> Mon Jan 25 15:41:24 2016 -0800
committer Serguei Katkov <serguei.i.katkov@intel.com> Tue Jan 26 10:46:54 2016 +0600
tree 5756c6bf6fd5321c9ead15edfa88e147ff45ac8f
parent 1af0204dddc1d99dc17a13eca135c1b57023c1c3

[WIP] ART Mterp: fix for hidden gc roots

To support moving gc, we must not hold onto any references solely
in registers across potential gc points.  This was happening during
returns, instance-of and check-cast.

[testing in progress]

Change-Id: I367750658c5716960737f0666e46800240fd392d

runtime/interpreter/mterp/mterp.cc

diff --git a/runtime/interpreter/mterp/mterp.cc b/runtime/interpreter/mterp/mterp.cc
index 9975458..0afd276 100644
--- a/runtime/interpreter/mterp/mterp.cc
+++ b/runtime/interpreter/mterp/mterp.cc
@@ -274,13 +274,15 @@
   return false;
 }
 
-extern "C" bool MterpCheckCast(uint32_t index, Object* obj, art::ArtMethod* method,
-                               Thread* self)
+extern "C" bool MterpCheckCast(uint32_t index, StackReference<mirror::Object>* vreg_addr,
+                               art::ArtMethod* method, Thread* self)
     SHARED_REQUIRES(Locks::mutator_lock_) {
   Class* c = ResolveVerifyAndClinit(index, method, self, false, false);
   if (UNLIKELY(c == nullptr)) {
     return true;
   }
+  // Must load obj from vreg following ResolveVerifyAndClinit due to moving gc.
+  Object* obj = vreg_addr->AsMirrorPtr();
   if (UNLIKELY(obj != nullptr && !obj->InstanceOf(c))) {
     ThrowClassCastException(c, obj->GetClass());
     return true;
@@ -288,13 +290,15 @@
   return false;
 }
 
-extern "C" bool MterpInstanceOf(uint32_t index, Object* obj, art::ArtMethod* method,
-                                Thread* self)
+extern "C" bool MterpInstanceOf(uint32_t index, StackReference<mirror::Object>* vreg_addr,
+                                art::ArtMethod* method, Thread* self)
     SHARED_REQUIRES(Locks::mutator_lock_) {
   Class* c = ResolveVerifyAndClinit(index, method, self, false, false);
   if (UNLIKELY(c == nullptr)) {
     return false;  // Caller will check for pending exception.  Return value unimportant.
   }
+  // Must load obj from vreg following ResolveVerifyAndClinit due to moving gc.
+  Object* obj = vreg_addr->AsMirrorPtr();
   return (obj != nullptr) && obj->InstanceOf(c);
 }
 
@@ -505,8 +509,7 @@
                                                uint64_t* new_value, Thread* self)
     SHARED_REQUIRES(Locks::mutator_lock_) {
   ScopedQuickEntrypointChecks sqec(self);
-  ArtField* field = FindFieldFast(field_idx, referrer, StaticPrimitiveWrite,
-                                          sizeof(int64_t));
+  ArtField* field = FindFieldFast(field_idx, referrer, StaticPrimitiveWrite, sizeof(int64_t));
   if (LIKELY(field != nullptr)) {
     // Compiled code can't use transactional mode.
     field->Set64<false>(field->GetDeclaringClass(), *new_value);
@@ -524,8 +527,7 @@
 extern "C" int artSet8InstanceFromMterp(uint32_t field_idx, mirror::Object* obj, uint8_t new_value,
                                         ArtMethod* referrer)
     SHARED_REQUIRES(Locks::mutator_lock_) {
-  ArtField* field = FindFieldFast(field_idx, referrer, InstancePrimitiveWrite,
-                                          sizeof(int8_t));
+  ArtField* field = FindFieldFast(field_idx, referrer, InstancePrimitiveWrite, sizeof(int8_t));
   if (LIKELY(field != nullptr && obj != nullptr)) {
     Primitive::Type type = field->GetTypeAsPrimitiveType();
     if (type == Primitive::kPrimBoolean) {
@@ -582,7 +584,7 @@
 }
 
 extern "C" int artSetObjInstanceFromMterp(uint32_t field_idx, mirror::Object* obj,
-                                         mirror::Object* new_value, ArtMethod* referrer)
+                                          mirror::Object* new_value, ArtMethod* referrer)
     SHARED_REQUIRES(Locks::mutator_lock_) {
   ArtField* field = FindFieldFast(field_idx, referrer, InstanceObjectWrite,
                                           sizeof(mirror::HeapReference<mirror::Object>));