riscv64: re-enable an invoke fast path

The meaning of ART_METHOD_NTERP_INVOKE_FAST_PATH_FLAG_BIT
for RISC-V narrows the condition to object refs only.

See invoke.S for notes on code structure.

Test: Run these opcodes against all interpreter
tests on a Linux RISC-V VM.

(1) setup
  lunch aosp_riscv64-trunk-userdebug

  export ART_TEST_SSH_USER=ubuntu
  export ART_TEST_SSH_HOST=localhost
  export ART_TEST_SSH_PORT=10001
  export ART_TEST_ON_VM=true

  . art/tools/buildbot-utils.sh
  art/tools/buildbot-build.sh --target

  # Create, boot and configure the VM.
  art/tools/buildbot-vm.sh create
  art/tools/buildbot-vm.sh boot
  art/tools/buildbot-vm.sh setup-ssh  # password: 'ubuntu'

  art/tools/buildbot-cleanup-device.sh
  art/tools/buildbot-setup-device.sh
  art/tools/buildbot-sync.sh

(2) test
  art/test.py --target -r --no-prebuild --ndebug --64  -j 12 --cdex-none --interpreter

Clean with `m check_cfi`.

Bug: 283082047
Change-Id: Ie1ecee895cb6d8abad40970041e95388feb530e2

1 files changed, 6 insertions, 7 deletions

diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index d08fe23439..3b0dda299e 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -4005,13 +4005,12 @@ void ClassLinker::LoadMethod(const DexFile& dex_file,
       }
     }
   }
-  if (all_parameters_are_reference_or_int && shorty[0] != 'F' && shorty[0] != 'D') {
-    // FIXME(riscv64): This optimization is currently disabled because riscv64 needs
-    // to distinguish between zero-extended references and sign-extended integers.
-    // We should enable this for references only and fix corresponding nterp fast-paths.
-    if (kRuntimeISA != InstructionSet::kRiscv64) {
-      access_flags |= kAccNterpInvokeFastPathFlag;
-    }
+  if (kRuntimeISA != InstructionSet::kRiscv64 && all_parameters_are_reference_or_int &&
+      shorty[0] != 'F' && shorty[0] != 'D') {
+    access_flags |= kAccNterpInvokeFastPathFlag;
+  } else if (kRuntimeISA == InstructionSet::kRiscv64 && all_parameters_are_reference &&
+             shorty[0] != 'F' && shorty[0] != 'D') {
+    access_flags |= kAccNterpInvokeFastPathFlag;
   }
 
   if (UNLIKELY((access_flags & kAccNative) != 0u)) {