Improve HLoadClass code generation.

For classes in the boot image, use either direct pointers
or PC-relative addresses. For other classes, use PC-relative
access to the dex cache arrays for AOT and direct address of
the type's dex cache slot for JIT.

For aosp_flounder-userdebug:
  - 32-bit boot.oat: -252KiB (-0.3%)
  - 64-bit boot.oat: -412KiB (-0.4%)
  - 32-bit dalvik cache total: -392KiB (-0.4%)
  - 64-bit dalvik-cache total: -2312KiB (-1.0%)
    (contains more files than the 32-bit dalvik cache)
For aosp_flounder-userdebug forced to compile PIC:
  - 32-bit boot.oat: -124KiB (-0.2%)
  - 64-bit boot.oat: -420KiB (-0.5%)
  - 32-bit dalvik cache total: -136KiB (-0.1%)
  - 64-bit dalvik-cache total: -1136KiB (-0.5%)
    (contains more files than the 32-bit dalvik cache)

Bug: 27950288
Change-Id: I4da991a4b7e53c63c92558b97923d18092acf139
diff --git a/compiler/optimizing/code_generator_mips64.cc b/compiler/optimizing/code_generator_mips64.cc
index 539abf1..1a20f5c 100644
--- a/compiler/optimizing/code_generator_mips64.cc
+++ b/compiler/optimizing/code_generator_mips64.cc
@@ -3016,6 +3016,13 @@
   return HLoadString::LoadKind::kDexCacheViaMethod;
 }
 
+HLoadClass::LoadKind CodeGeneratorMIPS64::GetSupportedLoadClassKind(
+    HLoadClass::LoadKind desired_class_load_kind) {
+  DCHECK_NE(desired_class_load_kind, HLoadClass::LoadKind::kReferrersClass);
+  // TODO: Implement other kinds.
+  return HLoadClass::LoadKind::kDexCacheViaMethod;
+}
+
 HInvokeStaticOrDirect::DispatchInfo CodeGeneratorMIPS64::GetSupportedInvokeStaticOrDirectDispatch(
       const HInvokeStaticOrDirect::DispatchInfo& desired_dispatch_info,
       MethodReference target_method ATTRIBUTE_UNUSED) {