x86_64: Implement VarHandle.get{,Acquire,Opaque,Volatile} for arrays.

Benchmarks improvements (using benchmarks provided by
https://android-review.googlesource.com/1420959):

  benchmark                              before   after
  -----------------------------------------------------
  VarHandleGetArrayElementInt            2.725    0.002
  VarHandleGetArrayElementString         2.778    0.003

Bug: 71781600
Test: lunch aosp_cf_x86_64_phone-userdebug \
  && art/test.py --host -r -t 712-varhandle-invocations --64
Test: Repeat with ART_USE_READ_BARRIER=false.
Test: Repeat with ART_HEAP_POISONING=true.
Change-Id: Ie9c6cef4ef3cf459cbfebbc17d1f449c489ec357

1 files changed, 12 insertions, 0 deletions

diff --git a/compiler/optimizing/intrinsics_utils.h b/compiler/optimizing/intrinsics_utils.h
index 546d5b3b93..3713b32a6c 100644
--- a/compiler/optimizing/intrinsics_utils.h
+++ b/compiler/optimizing/intrinsics_utils.h
@@ -146,6 +146,18 @@ static inline bool IsVarHandleGetAndAdd(HInvoke* invoke) {
   }
 }
 
+static inline DataType::Type GetVarHandleExpectedValueType(HInvoke* invoke,
+                                                           size_t expected_coordinates_count) {
+  DCHECK_EQ(expected_coordinates_count, GetExpectedVarHandleCoordinatesCount(invoke));
+  uint32_t number_of_arguments = invoke->GetNumberOfArguments();
+  DCHECK_GE(number_of_arguments, /* VarHandle object */ 1u + expected_coordinates_count);
+  if (number_of_arguments == /* VarHandle object */ 1u + expected_coordinates_count) {
+    return invoke->GetType();
+  } else {
+    return GetDataTypeFromShorty(invoke, number_of_arguments - 1u);
+  }
+}
+
 }  // namespace art
 
 #endif  // ART_COMPILER_OPTIMIZING_INTRINSICS_UTILS_H_