10 files changed, 474 insertions, 237 deletions

diff --git a/runtime/interpreter/interpreter_common.cc b/runtime/interpreter/interpreter_common.cc
index 5e4bb4145d..cb775cd7a3 100644
--- a/runtime/interpreter/interpreter_common.cc
+++ b/runtime/interpreter/interpreter_common.cc
@@ -827,6 +827,20 @@ inline static ObjPtr<mirror::Class> GetAndInitializeDeclaringClass(Thread* self,
   return klass;
 }
 
+// Returns true iff. the callsite type for a polymorphic invoke is transformer
+// like, i.e that it has a single input argument whose type is
+// dalvik.system.EmulatedStackFrame.
+static inline bool IsCallerTransformer(Handle<mirror::MethodType> callsite_type)
+    REQUIRES_SHARED(Locks::mutator_lock_) {
+  ObjPtr<mirror::ObjectArray<mirror::Class>> param_types(callsite_type->GetPTypes());
+  if (param_types->GetLength() == 1) {
+    ObjPtr<mirror::Class> param(param_types->GetWithoutChecks(0));
+    return param == WellKnownClasses::ToClass(WellKnownClasses::dalvik_system_EmulatedStackFrame);
+  }
+
+  return false;
+}
+
 template<bool is_range, bool do_access_check>
 inline bool DoInvokePolymorphic(Thread* self,
                                 ShadowFrame& shadow_frame,
@@ -838,6 +852,11 @@ inline bool DoInvokePolymorphic(Thread* self,
   const uint32_t vRegC = (is_range) ? inst->VRegC_4rcc() : inst->VRegC_45cc();
   const int invoke_method_idx = (is_range) ? inst->VRegB_4rcc() : inst->VRegB_45cc();
 
+  // Initialize |result| to 0 as this is the default return value for
+  // polymorphic invocations of method handle types with void return
+  // and provides sane return result in error cases.
+  result->SetJ(0);
+
   // Determine if this invocation is MethodHandle.invoke() or
   // MethodHandle.invokeExact().
   bool is_invoke_exact = IsInvokeExact(shadow_frame.GetMethod()->GetDeclaringClass()->GetDexFile(),
@@ -859,7 +878,6 @@ inline bool DoInvokePolymorphic(Thread* self,
     // Note that the invoke type is kVirtual here because a call to a signature
     // polymorphic method is shaped like a virtual call at the bytecode level.
     ThrowNullPointerExceptionForMethodAccess(invoke_method_idx, InvokeType::kVirtual);
-    result->SetJ(0);
     return false;
   }
 
@@ -880,14 +898,13 @@ inline bool DoInvokePolymorphic(Thread* self,
   // This implies we couldn't resolve one or more types in this method handle.
   if (UNLIKELY(callsite_type.Get() == nullptr)) {
     CHECK(self->IsExceptionPending());
-    result->SetJ(0);
     return false;
   }
 
   const MethodHandleKind handle_kind = method_handle->GetHandleKind();
   Handle<mirror::MethodType> handle_type(hs.NewHandle(method_handle->GetMethodType()));
   CHECK(handle_type.Get() != nullptr);
-  if (is_invoke_exact) {
+  {
     // We need to check the nominal type of the handle in addition to the
     // real type. The "nominal" type is present when MethodHandle.asType is
     // called any handle, and results in the declared type of the handle
@@ -900,9 +917,17 @@ inline bool DoInvokePolymorphic(Thread* self,
       check_type.Assign(nominal_type.Ptr());
     }
 
-    if (UNLIKELY(!callsite_type->IsExactMatch(check_type.Ptr()))) {
-      ThrowWrongMethodTypeException(check_type.Ptr(), callsite_type.Get());
-      return false;
+    if (is_invoke_exact) {
+      if (UNLIKELY(!callsite_type->IsExactMatch(check_type.Ptr()))) {
+        ThrowWrongMethodTypeException(check_type.Ptr(), callsite_type.Get());
+        return false;
+      }
+    } else {
+      if (UNLIKELY(!IsCallerTransformer(callsite_type) &&
+                   !callsite_type->IsConvertible(check_type.Ptr()))) {
+        ThrowWrongMethodTypeException(check_type.Ptr(), callsite_type.Get());
+        return false;
+      }
     }
   }
 
@@ -932,7 +957,7 @@ inline bool DoInvokePolymorphic(Thread* self,
       // TODO: Unfortunately, we have to postpone dynamic receiver based checks
       // because the receiver might be cast or might come from an emulated stack
       // frame, which means that it is unknown at this point. We perform these
-      // checks inside DoCallPolymorphic right before we do the actualy invoke.
+      // checks inside DoCallPolymorphic right before we do the actual invoke.
     } else if (handle_kind == kInvokeDirect) {
       // String constructors are a special case, they are replaced with StringFactory
       // methods.
@@ -965,40 +990,38 @@ inline bool DoInvokePolymorphic(Thread* self,
       CHECK(called_method != nullptr);
     }
 
+    bool call_success;
     if (handle_kind == kInvokeTransform) {
-      return DoCallTransform<is_range>(called_method,
-                                       callsite_type,
-                                       handle_type,
-                                       self,
-                                       shadow_frame,
-                                       method_handle /* receiver */,
-                                       result,
-                                       arg,
-                                       first_src_reg);
+      call_success = DoCallTransform<is_range>(called_method,
+                                               callsite_type,
+                                               handle_type,
+                                               self,
+                                               shadow_frame,
+                                               method_handle /* receiver */,
+                                               result,
+                                               arg,
+                                               first_src_reg);
     } else {
-      return DoCallPolymorphic<is_range>(called_method,
-                                         callsite_type,
-                                         handle_type,
-                                         self,
-                                         shadow_frame,
-                                         result,
-                                         arg,
-                                         first_src_reg,
-                                         handle_kind);
+      call_success = DoCallPolymorphic<is_range>(called_method,
+                                                 callsite_type,
+                                                 handle_type,
+                                                 self,
+                                                 shadow_frame,
+                                                 result,
+                                                 arg,
+                                                 first_src_reg,
+                                                 handle_kind);
+    }
+    if (LIKELY(call_success && ConvertReturnValue(callsite_type, handle_type, result))) {
+      return true;
     }
+    DCHECK(self->IsExceptionPending());
+    return false;
   } else {
     DCHECK(!is_range);
     ArtField* field = method_handle->GetTargetField();
     Primitive::Type field_type = field->GetTypeAsPrimitiveType();;
 
-    if (!is_invoke_exact) {
-      if (handle_type->GetPTypes()->GetLength() != callsite_type->GetPTypes()->GetLength()) {
-        // Too many arguments to setter or getter.
-        ThrowWrongMethodTypeException(callsite_type.Get(), handle_type.Get());
-        return false;
-      }
-    }
-
     switch (handle_kind) {
       case kInstanceGet: {
         ObjPtr<mirror::Object> obj = shadow_frame.GetVRegReference(first_src_reg);
@@ -1029,7 +1052,6 @@ inline bool DoInvokePolymorphic(Thread* self,
           return false;
         }
         ObjPtr<mirror::Object> obj = shadow_frame.GetVRegReference(first_src_reg);
-        result->SetL(0);
         return DoFieldPutForInvokePolymorphic(self, shadow_frame, obj, field, field_type, value);
       }
       case kStaticPut: {
@@ -1039,7 +1061,6 @@ inline bool DoInvokePolymorphic(Thread* self,
           return false;
         }
         ObjPtr<mirror::Object> obj = field->GetDeclaringClass();
-        result->SetL(0);
         return DoFieldPutForInvokePolymorphic(self, shadow_frame, obj, field, field_type, value);
       }
       default:
@@ -1120,20 +1141,6 @@ inline void CopyRegisters(ShadowFrame& caller_frame,
   }
 }
 
-// Returns true iff. the callsite type for a polymorphic invoke is transformer
-// like, i.e that it has a single input argument whose type is
-// dalvik.system.EmulatedStackFrame.
-static inline bool IsCallerTransformer(Handle<mirror::MethodType> callsite_type)
-    REQUIRES_SHARED(Locks::mutator_lock_) {
-  ObjPtr<mirror::ObjectArray<mirror::Class>> param_types(callsite_type->GetPTypes());
-  if (param_types->GetLength() == 1) {
-    ObjPtr<mirror::Class> param(param_types->GetWithoutChecks(0));
-    return param == WellKnownClasses::ToClass(WellKnownClasses::dalvik_system_EmulatedStackFrame);
-  }
-
-  return false;
-}
-
 template <bool is_range>
 static inline bool DoCallPolymorphic(ArtMethod* called_method,
                                      Handle<mirror::MethodType> callsite_type,
@@ -1245,8 +1252,6 @@ static inline bool DoCallPolymorphic(ArtMethod* called_method,
 
   PerformCall(self, code_item, shadow_frame.GetMethod(), first_dest_reg, new_shadow_frame, result);
 
-  // TODO(narayan): Perform return value conversions.
-
   // If the caller of this signature polymorphic method was a transformer,
   // we need to copy the result back out to the emulated stack frame.
   if (is_caller_transformer && !self->IsExceptionPending()) {
diff --git a/runtime/method_handles.cc b/runtime/method_handles.cc
index 491d13926f..f1adc32ce2 100644
--- a/runtime/method_handles.cc
+++ b/runtime/method_handles.cc
@@ -21,168 +21,70 @@
 #include "jvalue-inl.h"
 #include "reflection.h"
 #include "reflection-inl.h"
+#include "well_known_classes.h"
 
 namespace art {
 
 namespace {
 
-static const char* kBoxedBooleanClass = "Ljava/lang/Boolean;";
-static const char* kBoxedByteClass = "Ljava/lang/Byte;";
-static const char* kBoxedCharacterClass = "Ljava/lang/Character;";
-static const char* kBoxedDoubleClass = "Ljava/lang/Double;";
-static const char* kBoxedFloatClass = "Ljava/lang/Float;";
-static const char* kBoxedIntegerClass = "Ljava/lang/Integer;";
-static const char* kBoxedLongClass = "Ljava/lang/Long;";
-static const char* kBoxedShortClass = "Ljava/lang/Short;";
+#define PRIMITIVES_LIST(V) \
+  V(Primitive::kPrimBoolean, Boolean, Boolean, Z) \
+  V(Primitive::kPrimByte, Byte, Byte, B)          \
+  V(Primitive::kPrimChar, Char, Character, C)     \
+  V(Primitive::kPrimShort, Short, Short, S)       \
+  V(Primitive::kPrimInt, Int, Integer, I)         \
+  V(Primitive::kPrimLong, Long, Long, J)          \
+  V(Primitive::kPrimFloat, Float, Float, F)       \
+  V(Primitive::kPrimDouble, Double, Double, D)
 
 // Assigns |type| to the primitive type associated with |klass|. Returns
 // true iff. |klass| was a boxed type (Integer, Long etc.), false otherwise.
 bool GetUnboxedPrimitiveType(ObjPtr<mirror::Class> klass, Primitive::Type* type)
     REQUIRES_SHARED(Locks::mutator_lock_) {
   ScopedAssertNoThreadSuspension ants(__FUNCTION__);
-  if (klass->DescriptorEquals(kBoxedBooleanClass)) {
-    (*type) = Primitive::kPrimBoolean;
-    return true;
-  } else if (klass->DescriptorEquals(kBoxedByteClass)) {
-    (*type) = Primitive::kPrimByte;
-    return true;
-  } else if (klass->DescriptorEquals(kBoxedCharacterClass)) {
-    (*type) = Primitive::kPrimChar;
-    return true;
-  } else if (klass->DescriptorEquals(kBoxedFloatClass)) {
-    (*type) = Primitive::kPrimFloat;
-    return true;
-  } else if (klass->DescriptorEquals(kBoxedDoubleClass)) {
-    (*type) = Primitive::kPrimDouble;
-    return true;
-  } else if (klass->DescriptorEquals(kBoxedIntegerClass)) {
-    (*type) = Primitive::kPrimInt;
-    return true;
-  } else if (klass->DescriptorEquals(kBoxedLongClass)) {
-    (*type) = Primitive::kPrimLong;
-    return true;
-  } else if (klass->DescriptorEquals(kBoxedShortClass)) {
-    (*type) = Primitive::kPrimShort;
-    return true;
-  } else {
-    return false;
+#define LOOKUP_PRIMITIVE(primitive, _, __, ___)                         \
+  if (klass->DescriptorEquals(Primitive::BoxedDescriptor(primitive))) { \
+    *type = primitive;                                                  \
+    return true;                                                        \
   }
+
+  PRIMITIVES_LIST(LOOKUP_PRIMITIVE);
+#undef LOOKUP_PRIMITIVE
+  return false;
 }
 
-// Returns the class corresponding to the boxed type for the primitive |type|.
 ObjPtr<mirror::Class> GetBoxedPrimitiveClass(Primitive::Type type)
     REQUIRES_SHARED(Locks::mutator_lock_) {
   ScopedAssertNoThreadSuspension ants(__FUNCTION__);
-  ClassLinker* const class_linker = Runtime::Current()->GetClassLinker();
+  jmethodID m = nullptr;
   switch (type) {
-    case Primitive::kPrimBoolean:
-      return class_linker->FindSystemClass(Thread::Current(), kBoxedBooleanClass);
-    case Primitive::kPrimByte:
-      return class_linker->FindSystemClass(Thread::Current(), kBoxedByteClass);
-    case Primitive::kPrimChar:
-      return class_linker->FindSystemClass(Thread::Current(), kBoxedCharacterClass);
-    case Primitive::kPrimShort:
-      return class_linker->FindSystemClass(Thread::Current(), kBoxedShortClass);
-    case Primitive::kPrimInt:
-      return class_linker->FindSystemClass(Thread::Current(), kBoxedIntegerClass);
-    case Primitive::kPrimLong:
-      return class_linker->FindSystemClass(Thread::Current(), kBoxedLongClass);
-    case Primitive::kPrimFloat:
-      return class_linker->FindSystemClass(Thread::Current(), kBoxedFloatClass);
-    case Primitive::kPrimDouble:
-      return class_linker->FindSystemClass(Thread::Current(), kBoxedDoubleClass);
-    case Primitive::kPrimNot:
-    case Primitive::kPrimVoid:
-      LOG(FATAL) << "Unreachable";
+#define CASE_PRIMITIVE(primitive, _, java_name, __)              \
+    case primitive:                                              \
+      m = WellKnownClasses::java_lang_ ## java_name ## _valueOf; \
+      break;
+    PRIMITIVES_LIST(CASE_PRIMITIVE);
+#undef CASE_PRIMITIVE
+    case Primitive::Type::kPrimNot:
+    case Primitive::Type::kPrimVoid:
       return nullptr;
   }
+  return jni::DecodeArtMethod(m)->GetDeclaringClass();
 }
 
-// Returns true if |klass| is a boxed primitive type or a sub-class of a boxed primitive type.
-bool IsSubClassOfBoxedPrimitive(const Handle<mirror::Class>& klass)
-    REQUIRES_SHARED(Locks::mutator_lock_) {
-  StackHandleScope<1> hs(Thread::Current());
-  MutableHandle<mirror::Class> h_klass(hs.NewHandle(klass.Get()));
-  do {
-    Primitive::Type type;
-    if (GetUnboxedPrimitiveType(h_klass.Get(), &type)) {
-      return true;
-    }
-    h_klass.Assign(h_klass->GetSuperClass());
-  } while (h_klass.Get() != nullptr);
-  return false;
-}
-
-// Unboxed the value |o| to |unboxed_value| of type |dst_class|.
-// |unboxed_value| must be zero on entry to avoid dangling pointers.
-// Returns true on success, false if an exception is raised.
-bool UnboxPrimitiveForMethodHandles(ObjPtr<mirror::Object> o,
-                                    ObjPtr<mirror::Class> dst_class,
-                                    JValue* unboxed_value)
+bool GetUnboxedTypeAndValue(ObjPtr<mirror::Object> o, Primitive::Type* type, JValue* value)
     REQUIRES_SHARED(Locks::mutator_lock_) {
-  // Check unboxed_value does not contain a dangling pointer.
-  DCHECK_EQ(unboxed_value->GetJ(), 0);
-  DCHECK(dst_class->IsPrimitive());
-
-  // This is derived from UnboxPrimitive() in reflection.cc, but with
-  // exceptions appropriate to method handles.
-  if (UNLIKELY(dst_class->GetPrimitiveType() == Primitive::kPrimVoid)) {
-    ThrowClassCastException(o->GetClass(), dst_class);
-    return false;
-  }
-  if (UNLIKELY(o == nullptr)) {
-    ThrowNullPointerException(
-        StringPrintf("Expected to unbox a '%s' primitive type but was returned null",
-                     dst_class->PrettyDescriptor().c_str()).c_str());
-    return false;
-  }
-
-  JValue boxed_value;
+  ScopedAssertNoThreadSuspension ants(__FUNCTION__);
   ObjPtr<mirror::Class> klass = o->GetClass();
-  ObjPtr<mirror::Class> src_class = nullptr;
-  ClassLinker* const class_linker = Runtime::Current()->GetClassLinker();
   ArtField* primitive_field = &klass->GetIFieldsPtr()->At(0);
-  if (klass->DescriptorEquals(kBoxedBooleanClass)) {
-    src_class = class_linker->FindPrimitiveClass('Z');
-    boxed_value.SetZ(primitive_field->GetBoolean(o));
-  } else if (klass->DescriptorEquals(kBoxedByteClass)) {
-    src_class = class_linker->FindPrimitiveClass('B');
-    boxed_value.SetB(primitive_field->GetByte(o));
-  } else if (klass->DescriptorEquals(kBoxedCharacterClass)) {
-    src_class = class_linker->FindPrimitiveClass('C');
-    boxed_value.SetC(primitive_field->GetChar(o));
-  } else if (klass->DescriptorEquals(kBoxedFloatClass)) {
-    src_class = class_linker->FindPrimitiveClass('F');
-    boxed_value.SetF(primitive_field->GetFloat(o));
-  } else if (klass->DescriptorEquals(kBoxedDoubleClass)) {
-    src_class = class_linker->FindPrimitiveClass('D');
-    boxed_value.SetD(primitive_field->GetDouble(o));
-  } else if (klass->DescriptorEquals(kBoxedIntegerClass)) {
-    src_class = class_linker->FindPrimitiveClass('I');
-    boxed_value.SetI(primitive_field->GetInt(o));
-  } else if (klass->DescriptorEquals(kBoxedLongClass)) {
-    src_class = class_linker->FindPrimitiveClass('J');
-    boxed_value.SetJ(primitive_field->GetLong(o));
-  } else if (klass->DescriptorEquals(kBoxedShortClass)) {
-    src_class = class_linker->FindPrimitiveClass('S');
-    boxed_value.SetS(primitive_field->GetShort(o));
-  } else {
-    std::string temp;
-    ThrowIllegalArgumentException(
-        StringPrintf("result has type %s, got %s",
-                     dst_class->PrettyDescriptor().c_str(),
-                     PrettyDescriptor(o->GetClass()->GetDescriptor(&temp)).c_str()).c_str());
-    return false;
+#define CASE_PRIMITIVE(primitive, abbrev, _, shorthand)         \
+  if (klass == GetBoxedPrimitiveClass(primitive)) {             \
+    *type = primitive;                                          \
+    value->Set ## shorthand(primitive_field->Get ## abbrev(o)); \
+    return true;                                                \
   }
-
-  if (!ConvertPrimitiveValueNoThrow(src_class->GetPrimitiveType(),
-                                    dst_class->GetPrimitiveType(),
-                                    boxed_value,
-                                    unboxed_value)) {
-    ThrowClassCastException(src_class, dst_class);
-    return false;
-  }
-  return true;
+  PRIMITIVES_LIST(CASE_PRIMITIVE)
+#undef CASE_PRIMITIVE
+  return false;
 }
 
 inline bool IsReferenceType(Primitive::Type type) {
@@ -195,6 +97,71 @@ inline bool IsPrimitiveType(Primitive::Type type) {
 
 }  // namespace
 
+bool IsParameterTypeConvertible(ObjPtr<mirror::Class> from, ObjPtr<mirror::Class> to)
+    REQUIRES_SHARED(Locks::mutator_lock_) {
+  // This function returns true if there's any conceivable conversion
+  // between |from| and |to|. It's expected this method will be used
+  // to determine if a WrongMethodTypeException should be raised. The
+  // decision logic follows the documentation for MethodType.asType().
+  if (from == to) {
+    return true;
+  }
+
+  Primitive::Type from_primitive = from->GetPrimitiveType();
+  Primitive::Type to_primitive = to->GetPrimitiveType();
+  DCHECK(from_primitive != Primitive::Type::kPrimVoid);
+  DCHECK(to_primitive != Primitive::Type::kPrimVoid);
+
+  // If |to| and |from| are references.
+  if (IsReferenceType(from_primitive) && IsReferenceType(to_primitive)) {
+    // Assignability is determined during parameter conversion when
+    // invoking the associated method handle.
+    return true;
+  }
+
+  // If |to| and |from| are primitives and a widening conversion exists.
+  if (Primitive::IsWidenable(from_primitive, to_primitive)) {
+    return true;
+  }
+
+  // If |to| is a reference and |from| is a primitive, then boxing conversion.
+  if (IsReferenceType(to_primitive) && IsPrimitiveType(from_primitive)) {
+    return to->IsAssignableFrom(GetBoxedPrimitiveClass(from_primitive));
+  }
+
+  // If |from| is a reference and |to| is a primitive, then unboxing conversion.
+  if (IsPrimitiveType(to_primitive) && IsReferenceType(from_primitive)) {
+    if (from->DescriptorEquals("Ljava/lang/Object;")) {
+      // Object might be converted into a primitive during unboxing.
+      return true;
+    } else if (Primitive::IsNumericType(to_primitive) &&
+               from->DescriptorEquals("Ljava/lang/Number;")) {
+      // Number might be unboxed into any of the number primitive types.
+      return true;
+    }
+    Primitive::Type unboxed_type;
+    if (GetUnboxedPrimitiveType(from, &unboxed_type)) {
+      return Primitive::IsWidenable(unboxed_type, to_primitive);
+    }
+  }
+
+  return false;
+}
+
+bool IsReturnTypeConvertible(ObjPtr<mirror::Class> from, ObjPtr<mirror::Class> to)
+    REQUIRES_SHARED(Locks::mutator_lock_) {
+  if (to->GetPrimitiveType() == Primitive::Type::kPrimVoid) {
+    // Result will be ignored.
+    return true;
+  } else if (from->GetPrimitiveType() == Primitive::Type::kPrimVoid) {
+    // Returned value will be 0 / null.
+    return true;
+  } else {
+    // Otherwise apply usual parameter conversion rules.
+    return IsParameterTypeConvertible(from, to);
+  }
+}
+
 bool ConvertJValueCommon(
     Handle<mirror::MethodType> callsite_type,
     Handle<mirror::MethodType> callee_type,
@@ -209,14 +176,23 @@ bool ConvertJValueCommon(
   const Primitive::Type from_type = from->GetPrimitiveType();
   const Primitive::Type to_type = to->GetPrimitiveType();
 
+  // Put incoming value into |src_value| and set return value to 0.
+  // Errors and conversions from void require the return value to be 0.
+  const JValue src_value(*value);
+  value->SetJ(0);
+
+  // Conversion from void set result to zero.
+  if (from_type == Primitive::kPrimVoid) {
+    return true;
+  }
+
   // This method must be called only when the types don't match.
   DCHECK(from != to);
 
   if (IsPrimitiveType(from_type) && IsPrimitiveType(to_type)) {
     // The source and target types are both primitives.
-    if (UNLIKELY(!ConvertPrimitiveValueNoThrow(from_type, to_type, *value, value))) {
+    if (UNLIKELY(!ConvertPrimitiveValueNoThrow(from_type, to_type, src_value, value))) {
       ThrowWrongMethodTypeException(callee_type.Get(), callsite_type.Get());
-      value->SetJ(0);
       return false;
     }
     return true;
@@ -229,12 +205,7 @@ bool ConvertJValueCommon(
     // in mirror::Class::IsAssignable().
     StackHandleScope<2> hs(Thread::Current());
     Handle<mirror::Class> h_to(hs.NewHandle(to));
-    Handle<mirror::Object> h_obj(hs.NewHandle(value->GetL()));
-
-    // |value| will now be the result value, invalidate its existing value
-    // as |h_obj| now owns it.
-    value->SetJ(0);
-
+    Handle<mirror::Object> h_obj(hs.NewHandle(src_value.GetL()));
     if (h_obj.Get() != nullptr && !to->IsAssignableFrom(h_obj->GetClass())) {
       ThrowClassCastException(h_to.Get(), h_obj->GetClass());
       return false;
@@ -243,10 +214,6 @@ bool ConvertJValueCommon(
     return true;
   } else if (IsReferenceType(to_type)) {
     DCHECK(IsPrimitiveType(from_type));
-    // Playing it safe with StackHandleScope here with regards to
-    // GetUnboxedPrimitiveType() and GetBoxedPrimitiveClass().
-    StackHandleScope<1> hs(Thread::Current());
-    Handle<mirror::Class> h_to(hs.NewHandle(to));
     // The source type is a primitive and the target type is a reference, so we must box.
     // The target type maybe a super class of the boxed source type, for example,
     // if the source type is int, it's boxed type is java.lang.Integer, and the target
@@ -254,29 +221,26 @@ bool ConvertJValueCommon(
     Primitive::Type type;
     if (!GetUnboxedPrimitiveType(to, &type)) {
       ObjPtr<mirror::Class> boxed_from_class = GetBoxedPrimitiveClass(from_type);
-      if (boxed_from_class->IsSubClass(h_to.Get())) {
+      if (boxed_from_class->IsSubClass(to)) {
         type = from_type;
       } else {
-        value->SetJ(0);
         ThrowWrongMethodTypeException(callee_type.Get(), callsite_type.Get());
         return false;
       }
     }
 
     if (UNLIKELY(from_type != type)) {
-      value->SetJ(0);
       ThrowWrongMethodTypeException(callee_type.Get(), callsite_type.Get());
       return false;
     }
 
-    if (!ConvertPrimitiveValueNoThrow(from_type, type, *value, value)) {
-      value->SetJ(0);
+    if (!ConvertPrimitiveValueNoThrow(from_type, type, src_value, value)) {
       ThrowWrongMethodTypeException(callee_type.Get(), callsite_type.Get());
       return false;
     }
 
     // Then perform the actual boxing, and then set the reference.
-    ObjPtr<mirror::Object> boxed = BoxPrimitive(type, *value);
+    ObjPtr<mirror::Object> boxed = BoxPrimitive(type, src_value);
     value->SetL(boxed.Ptr());
     return true;
   } else {
@@ -284,33 +248,27 @@ bool ConvertJValueCommon(
     DCHECK(IsReferenceType(from_type));
     DCHECK(IsPrimitiveType(to_type));
 
-    // Use StackHandleScope to protect |from|, |to|, and the reference
-    // in |value| from heap re-arrangements that could be triggered
-    // ahead of unboxing step.
-    StackHandleScope<3> hs(Thread::Current());
-    Handle<mirror::Class> h_to(hs.NewHandle(to));
-    Handle<mirror::Class> h_from(hs.NewHandle(from));
-    Handle<mirror::Object> h_obj(hs.NewHandle(value->GetL()));
-
-    // |value| will now be the result value, invalidate its existing value
-    // as |h_obj| now owns it.
-    value->SetJ(0);
+    ObjPtr<mirror::Object> from_obj(src_value.GetL());
+    if (UNLIKELY(from_obj == nullptr)) {
+      ThrowNullPointerException(
+          StringPrintf("Expected to unbox a '%s' primitive type but was returned null",
+                       from->PrettyDescriptor().c_str()).c_str());
+      return false;
+    }
 
-    // Check source type is a boxed primitive or has a boxed primitive super-class.
-    ObjPtr<mirror::Class> boxed_to_class = GetBoxedPrimitiveClass(to_type);
-    if (!IsSubClassOfBoxedPrimitive(h_from) && !boxed_to_class->IsSubClass(h_from.Get())) {
+    Primitive::Type unboxed_type;
+    JValue unboxed_value;
+    if (UNLIKELY(!GetUnboxedTypeAndValue(from_obj, &unboxed_type, &unboxed_value))) {
       ThrowWrongMethodTypeException(callee_type.Get(), callsite_type.Get());
       return false;
     }
 
-    if (h_obj.Get() == nullptr) {
-      ThrowNullPointerException(
-        StringPrintf("Expected to unbox a '%s' but instance was null",
-                     h_from->PrettyDescriptor().c_str()).c_str());
+    if (UNLIKELY(!ConvertPrimitiveValueNoThrow(unboxed_type, to_type, unboxed_value, value))) {
+      ThrowClassCastException(from, to);
       return false;
     }
 
-    return UnboxPrimitiveForMethodHandles(h_obj.Get(), h_to.Get(), value);
+    return true;
   }
 }
 
diff --git a/runtime/method_handles.h b/runtime/method_handles.h
index 0cc69f2046..54c772a4f2 100644
--- a/runtime/method_handles.h
+++ b/runtime/method_handles.h
@@ -59,6 +59,16 @@ inline bool IsInvoke(const MethodHandleKind handle_kind) {
   return handle_kind <= kLastInvokeKind;
 }
 
+// Returns true if there is a possible conversion from |from| to |to|
+// for a MethodHandle parameter.
+bool IsParameterTypeConvertible(ObjPtr<mirror::Class> from,
+                                ObjPtr<mirror::Class> to);
+
+// Returns true if there is a possible conversion from |from| to |to|
+// for the return type of a MethodHandle.
+bool IsReturnTypeConvertible(ObjPtr<mirror::Class> from,
+                             ObjPtr<mirror::Class> to);
+
 // Performs a conversion from type |from| to a distinct type |to| as
 // part of conversion of |caller_type| to |callee_type|. The value to
 // be converted is in |value|. Returns true on success and updates
diff --git a/runtime/mirror/method_type.cc b/runtime/mirror/method_type.cc
index 9b0f87242c..5d77a16e7d 100644
--- a/runtime/mirror/method_type.cc
+++ b/runtime/mirror/method_type.cc
@@ -18,6 +18,7 @@
 
 #include "class-inl.h"
 #include "gc_root-inl.h"
+#include "method_handles.h"
 
 namespace art {
 namespace mirror {
@@ -43,25 +44,44 @@ mirror::MethodType* MethodType::Create(Thread* const self,
   return mt.Get();
 }
 
-bool MethodType::IsExactMatch(mirror::MethodType* other) REQUIRES_SHARED(Locks::mutator_lock_) {
-  if (GetRType() != other->GetRType()) {
+bool MethodType::IsExactMatch(mirror::MethodType* target) REQUIRES_SHARED(Locks::mutator_lock_) {
+  mirror::ObjectArray<Class>* const p_types = GetPTypes();
+  const int32_t params_length = p_types->GetLength();
+
+  mirror::ObjectArray<Class>* const target_p_types = target->GetPTypes();
+  if (params_length != target_p_types->GetLength()) {
     return false;
   }
+  for (int32_t i = 0; i < params_length; ++i) {
+    if (p_types->GetWithoutChecks(i) != target_p_types->GetWithoutChecks(i)) {
+      return false;
+    }
+  }
+  return GetRType() == target->GetRType();
+}
 
+bool MethodType::IsConvertible(mirror::MethodType* target) REQUIRES_SHARED(Locks::mutator_lock_) {
   mirror::ObjectArray<Class>* const p_types = GetPTypes();
   const int32_t params_length = p_types->GetLength();
 
-  mirror::ObjectArray<Class>* const other_p_types = other->GetPTypes();
-  if (params_length != other_p_types->GetLength()) {
+  mirror::ObjectArray<Class>* const target_p_types = target->GetPTypes();
+  if (params_length != target_p_types->GetLength()) {
+    return false;
+  }
+
+  // Perform return check before invoking method handle otherwise side
+  // effects from the invocation may be observable before
+  // WrongMethodTypeException is raised.
+  if (!IsReturnTypeConvertible(target->GetRType(), GetRType())) {
     return false;
   }
 
   for (int32_t i = 0; i < params_length; ++i) {
-    if (p_types->GetWithoutChecks(i) != other_p_types->GetWithoutChecks(i)) {
+    if (!IsParameterTypeConvertible(p_types->GetWithoutChecks(i),
+                                    target_p_types->GetWithoutChecks(i))) {
       return false;
     }
   }
-
   return true;
 }
 
diff --git a/runtime/mirror/method_type.h b/runtime/mirror/method_type.h
index fa700b68ff..9a98143144 100644
--- a/runtime/mirror/method_type.h
+++ b/runtime/mirror/method_type.h
@@ -52,9 +52,13 @@ class MANAGED MethodType : public Object {
   static void ResetClass() REQUIRES_SHARED(Locks::mutator_lock_);
   static void VisitRoots(RootVisitor* visitor) REQUIRES_SHARED(Locks::mutator_lock_);
 
-  // Returns true iff. |other| is an exact match for this method type, i.e
+  // Returns true iff. |this| is an exact match for method type |target|, i.e
   // iff. they have the same return types and parameter types.
-  bool IsExactMatch(mirror::MethodType* other) REQUIRES_SHARED(Locks::mutator_lock_);
+  bool IsExactMatch(mirror::MethodType* target) REQUIRES_SHARED(Locks::mutator_lock_);
+
+  // Returns true iff. |this| can be converted to match |target| method type, i.e
+  // iff. they have convertible return types and parameter types.
+  bool IsConvertible(mirror::MethodType* target) REQUIRES_SHARED(Locks::mutator_lock_);
 
   // Returns the pretty descriptor for this method type, suitable for display in
   // exception messages and the like.
diff --git a/runtime/primitive.cc b/runtime/primitive.cc
index d29a06043a..2380284535 100644
--- a/runtime/primitive.cc
+++ b/runtime/primitive.cc
@@ -31,11 +31,35 @@ static const char* kTypeNames[] = {
   "PrimVoid",
 };
 
+static const char* kBoxedDescriptors[] = {
+  "Ljava/lang/Object;",
+  "Ljava/lang/Boolean;",
+  "Ljava/lang/Byte;",
+  "Ljava/lang/Character;",
+  "Ljava/lang/Short;",
+  "Ljava/lang/Integer;",
+  "Ljava/lang/Long;",
+  "Ljava/lang/Float;",
+  "Ljava/lang/Double;",
+  "Ljava/lang/Void;",
+};
+
+#define COUNT_OF(x) (sizeof(x) / sizeof(x[0]))
+
 const char* Primitive::PrettyDescriptor(Primitive::Type type) {
+  static_assert(COUNT_OF(kTypeNames) == static_cast<size_t>(Primitive::kPrimLast) + 1,
+                "Missing element");
   CHECK(Primitive::kPrimNot <= type && type <= Primitive::kPrimVoid) << static_cast<int>(type);
   return kTypeNames[type];
 }
 
+const char* Primitive::BoxedDescriptor(Primitive::Type type) {
+  static_assert(COUNT_OF(kBoxedDescriptors) == static_cast<size_t>(Primitive::kPrimLast) + 1,
+                "Missing element");
+  CHECK(Primitive::kPrimNot <= type && type <= Primitive::kPrimVoid) << static_cast<int>(type);
+  return kBoxedDescriptors[type];
+}
+
 std::ostream& operator<<(std::ostream& os, const Primitive::Type& type) {
   int32_t int_type = static_cast<int32_t>(type);
   if (type >= Primitive::kPrimNot && type <= Primitive::kPrimVoid) {
diff --git a/runtime/primitive.h b/runtime/primitive.h
index 18f45ffe9d..7cc47ad79b 100644
--- a/runtime/primitive.h
+++ b/runtime/primitive.h
@@ -138,6 +138,9 @@ class Primitive {
 
   static const char* PrettyDescriptor(Type type);
 
+  // Returns the descriptor corresponding to the boxed type of |type|.
+  static const char* BoxedDescriptor(Type type);
+
   static bool IsFloatingPointType(Type type) {
     return type == kPrimFloat || type == kPrimDouble;
   }
@@ -158,6 +161,32 @@ class Primitive {
     }
   }
 
+  // Return true if |type| is an numeric type.
+  static bool IsNumericType(Type type) {
+    switch (type) {
+      case Primitive::Type::kPrimNot: return false;
+      case Primitive::Type::kPrimBoolean: return false;
+      case Primitive::Type::kPrimByte: return true;
+      case Primitive::Type::kPrimChar: return false;
+      case Primitive::Type::kPrimShort: return true;
+      case Primitive::Type::kPrimInt: return true;
+      case Primitive::Type::kPrimLong: return true;
+      case Primitive::Type::kPrimFloat: return true;
+      case Primitive::Type::kPrimDouble: return true;
+      case Primitive::Type::kPrimVoid: return false;
+    }
+  }
+
+  // Returns true if |from| and |to| are the same or a widening conversion exists between them.
+  static bool IsWidenable(Type from, Type to) {
+    static_assert(Primitive::Type::kPrimByte < Primitive::Type::kPrimShort, "Bad ordering");
+    static_assert(Primitive::Type::kPrimShort < Primitive::Type::kPrimInt, "Bad ordering");
+    static_assert(Primitive::Type::kPrimInt < Primitive::Type::kPrimLong, "Bad ordering");
+    static_assert(Primitive::Type::kPrimLong < Primitive::Type::kPrimFloat, "Bad ordering");
+    static_assert(Primitive::Type::kPrimFloat < Primitive::Type::kPrimDouble, "Bad ordering");
+    return IsNumericType(from) && IsNumericType(to) && from <= to;
+  }
+
   static bool IsIntOrLongType(Type type) {
     return type == kPrimInt || type == kPrimLong;
   }
diff --git a/test/956-methodhandles/expected.txt b/test/956-methodhandles/expected.txt
index 9ca448ce74..0a5caa157e 100644
--- a/test/956-methodhandles/expected.txt
+++ b/test/956-methodhandles/expected.txt
@@ -5,3 +5,5 @@ foo_B
 privateRyan_D
 Received exception: Expected (java.lang.String, java.lang.String)java.lang.String but was (java.lang.String, java.lang.Object)void
 String constructors done.
+testReferenceReturnValueConversions done.
+testPrimitiveReturnValueConversions done.
diff --git a/test/956-methodhandles/src/Main.java b/test/956-methodhandles/src/Main.java
index d0c658f819..3d714c9dc2 100644
--- a/test/956-methodhandles/src/Main.java
+++ b/test/956-methodhandles/src/Main.java
@@ -69,6 +69,7 @@ public class Main {
     testAsType();
     testConstructors();
     testStringConstructors();
+    testReturnValueConversions();
   }
 
   public static void testfindSpecial_invokeSuperBehaviour() throws Throwable {
@@ -685,6 +686,168 @@ public class Main {
 
     System.out.println("String constructors done.");
   }
-}
 
+  private static void testReferenceReturnValueConversions() throws Throwable {
+    MethodHandle mh = MethodHandles.lookup().findStatic(
+        Float.class, "valueOf", MethodType.methodType(Float.class, String.class));
+
+    // No conversion
+    Float f = (Float) mh.invokeExact("1.375");
+    if (f.floatValue() != 1.375) {
+      fail();
+    }
+    f = (Float) mh.invoke("1.875");
+    if (f.floatValue() != 1.875) {
+      fail();
+    }
+
+    // Bad conversion
+    try {
+      int i = (int) mh.invokeExact("7.77");
+      fail();
+    } catch (WrongMethodTypeException e) {}
+
+    try {
+      int i = (int) mh.invoke("7.77");
+      fail();
+    } catch (WrongMethodTypeException e) {}
+
+    // Assignment to super-class.
+    Number n = (Number) mh.invoke("1.11");
+    try {
+      Number o = (Number) mh.invokeExact("1.11");
+      fail();
+    } catch (WrongMethodTypeException e) {}
+
+    // Assignment to widened boxed primitive class.
+    try {
+      Double u = (Double) mh.invoke("1.11");
+      fail();
+    } catch (ClassCastException e) {}
+
+    try {
+      Double v = (Double) mh.invokeExact("1.11");
+      fail();
+    } catch (WrongMethodTypeException e) {}
+
+    // Unboxed
+    float p = (float) mh.invoke("1.11");
+    if (p != 1.11f) {
+      fail();
+    }
+
+    // Unboxed and widened
+    double d = (double) mh.invoke("2.5");
+    if (d != 2.5) {
+      fail();
+    }
+
+    // Interface
+    Comparable<Float> c = (Comparable<Float>) mh.invoke("2.125");
+    if (c.compareTo(new Float(2.125f)) != 0) {
+      fail();
+    }
+
+    System.out.println("testReferenceReturnValueConversions done.");
+  }
+
+  private static void testPrimitiveReturnValueConversions() throws Throwable {
+    MethodHandle mh = MethodHandles.lookup().findStatic(
+        Math.class, "min", MethodType.methodType(int.class, int.class, int.class));
+
+    final int SMALL = -8972;
+    final int LARGE = 7932529;
+
+    // No conversion
+    if ((int) mh.invokeExact(LARGE, SMALL) != SMALL) {
+      fail();
+    } else if ((int) mh.invoke(LARGE, SMALL) != SMALL) {
+      fail();
+    } else if ((int) mh.invokeExact(SMALL, LARGE) != SMALL) {
+      fail();
+    } else if ((int) mh.invoke(SMALL, LARGE) != SMALL) {
+      fail();
+    }
 
+    // int -> long
+    try {
+      if ((long) mh.invokeExact(LARGE, SMALL) != (long) SMALL) {}
+        fail();
+    } catch (WrongMethodTypeException e) {}
+
+    if ((long) mh.invoke(LARGE, SMALL) != (long) SMALL) {
+      fail();
+    }
+
+    // int -> short
+    try {
+      if ((short) mh.invokeExact(LARGE, SMALL) != (short) SMALL) {}
+      fail();
+    } catch (WrongMethodTypeException e) {}
+
+    try {
+      if ((short) mh.invoke(LARGE, SMALL) != (short) SMALL) {
+        fail();
+      }
+    } catch (WrongMethodTypeException e) {}
+
+    // int -> Integer
+    try {
+      if (!((Integer) mh.invokeExact(LARGE, SMALL)).equals(new Integer(SMALL))) {}
+      fail();
+    } catch (WrongMethodTypeException e) {}
+
+    if (!((Integer) mh.invoke(LARGE, SMALL)).equals(new Integer(SMALL))) {
+      fail();
+    }
+
+    // int -> Long
+    try {
+      Long l = (Long) mh.invokeExact(LARGE, SMALL);
+      fail();
+    } catch (WrongMethodTypeException e) {}
+
+    try {
+      Long l = (Long) mh.invoke(LARGE, SMALL);
+      fail();
+    } catch (WrongMethodTypeException e) {}
+
+    // int -> Short
+    try {
+      Short s = (Short) mh.invokeExact(LARGE, SMALL);
+      fail();
+    } catch (WrongMethodTypeException e) {}
+
+    try {
+      Short s = (Short) mh.invoke(LARGE, SMALL);
+      fail();
+    } catch (WrongMethodTypeException e) {}
+
+    // int -> Process
+    try {
+      Process p = (Process) mh.invokeExact(LARGE, SMALL);
+      fail();
+    } catch (WrongMethodTypeException e) {}
+
+    try {
+      Process p = (Process) mh.invoke(LARGE, SMALL);
+      fail();
+    } catch (WrongMethodTypeException e) {}
+
+    // void -> Object
+    mh = MethodHandles.lookup().findStatic(System.class, "gc", MethodType.methodType(void.class));
+    Object o = (Object) mh.invoke();
+    if (o != null) fail();
+
+    // void -> long
+    long l = (long) mh.invoke();
+    if (l != 0) fail();
+
+    System.out.println("testPrimitiveReturnValueConversions done.");
+  }
+
+  public static void testReturnValueConversions() throws Throwable {
+    testReferenceReturnValueConversions();
+    testPrimitiveReturnValueConversions();
+  }
+}
diff --git a/test/959-invoke-polymorphic-accessors/src/Main.java b/test/959-invoke-polymorphic-accessors/src/Main.java
index 824a436f3b..b7ecf8e818 100644
--- a/test/959-invoke-polymorphic-accessors/src/Main.java
+++ b/test/959-invoke-polymorphic-accessors/src/Main.java
@@ -780,16 +780,28 @@ public class Main {
             } catch (WrongMethodTypeException e) {}
         }
 
+        /*package*/ static Number getDoubleAsNumber() {
+            return new Double(1.4e77);
+        }
+        /*package*/ static Number getFloatAsNumber() {
+            return new Float(7.77);
+        }
+        /*package*/ static Object getFloatAsObject() {
+            return new Float(-7.77);
+        }
+
         private static void testMemberSetter() throws Throwable {
             ValueHolder valueHolder = new ValueHolder();
             MethodHandles.Lookup lookup = MethodHandles.lookup();
             MethodHandle h0 = lookup.findSetter(ValueHolder.class, "m_f", float.class);
             h0.invoke(valueHolder, 0.22f);
             h0.invoke(valueHolder, new Float(1.11f));
-            Number floatNumber = new Float(0.88f);
+            Number floatNumber = getFloatAsNumber();
             h0.invoke(valueHolder, floatNumber);
             assertTrue(valueHolder.m_f == floatNumber.floatValue());
-
+            Object objNumber = getFloatAsObject();
+            h0.invoke(valueHolder, objNumber);
+            assertTrue(valueHolder.m_f == ((Float) objNumber).floatValue());
             try {
               h0.invoke(valueHolder, (Float)null);
               unreachable();
@@ -799,12 +811,17 @@ public class Main {
             h0.invoke(valueHolder, (short)2);
             h0.invoke(valueHolder, 3);
             h0.invoke(valueHolder, 4l);
+
+            assertTrue(null == (Object) h0.invoke(valueHolder, 33));
+            assertTrue(0.0f == (float) h0.invoke(valueHolder, 33));
+            assertTrue(0l == (long) h0.invoke(valueHolder, 33));
+
             try {
                 h0.invoke(valueHolder, 0.33);
                 unreachable();
             } catch (WrongMethodTypeException e) {}
             try {
-                Number doubleNumber = new Double(0.89);
+                Number doubleNumber = getDoubleAsNumber();
                 h0.invoke(valueHolder, doubleNumber);
                 unreachable();
             } catch (ClassCastException e) {}
@@ -847,12 +864,17 @@ public class Main {
             h0.invoke((short)2);
             h0.invoke(3);
             h0.invoke(4l);
+
+            assertTrue(null == (Object) h0.invoke(33));
+            assertTrue(0.0f == (float) h0.invoke(33));
+            assertTrue(0l == (long) h0.invoke(33));
+
             try {
                 h0.invoke(0.33);
                 unreachable();
             } catch (WrongMethodTypeException e) {}
             try {
-                Number doubleNumber = new Double(0.89);
+                Number doubleNumber = getDoubleAsNumber();
                 h0.invoke(doubleNumber);
                 unreachable();
             } catch (ClassCastException e) {}