commit a3759ca5d8fd80cb1cf0856dd128f9a92c4c12f6
author Ulya Trafimovich <skvadrik@google.com> Fri Jan 14 15:53:42 2022 +0000
committer Ulya Trofimovich <skvadrik@google.com> Mon Jan 17 14:52:07 2022 +0000
tree e5e1b92e09387793e128a791f0c6bdb21a3f49b3
parent 70102e618a82c41c0e0c790db6959bc58d4837de

arm: Implement Unsafe.compareAndSetObject intrinsic.

The implementation is the same as Unsafe.compareAndSwapObject, as the
latter operation has compare-and-set semantics.

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

  benchmark                              before   after
  -----------------------------------------------------
  UnsafeCompareAndSetStaticFieldString   4.209    0.027
  UnsafeCompareAndSetFieldString         4.212    0.025

Bug: 71781600
Bug: 202868177
Test: art/test.py --target -r -t 712-varhandle-invocations
Change-Id: Ib6f071d5bc118018bec36204718ba0089df13302

compiler/optimizing/intrinsics_arm_vixl.cc

diff --git a/compiler/optimizing/intrinsics_arm_vixl.cc b/compiler/optimizing/intrinsics_arm_vixl.cc
index 2b49790..a4a3457 100644
--- a/compiler/optimizing/intrinsics_arm_vixl.cc
+++ b/compiler/optimizing/intrinsics_arm_vixl.cc
@@ -3656,7 +3656,8 @@
 static void CreateUnsafeCASLocations(ArenaAllocator* allocator, HInvoke* invoke) {
   bool can_call = kEmitCompilerReadBarrier &&
       (invoke->GetIntrinsic() == Intrinsics::kUnsafeCASObject ||
-       invoke->GetIntrinsic() == Intrinsics::kJdkUnsafeCASObject);
+       invoke->GetIntrinsic() == Intrinsics::kJdkUnsafeCASObject ||
+       invoke->GetIntrinsic() == Intrinsics::kJdkUnsafeCompareAndSetObject);
   LocationSummary* locations =
       new (allocator) LocationSummary(invoke,
                                       can_call
@@ -3756,6 +3757,28 @@
 void IntrinsicLocationsBuilderARMVIXL::VisitUnsafeCASObject(HInvoke* invoke) {
   VisitJdkUnsafeCASObject(invoke);
 }
+
+void IntrinsicLocationsBuilderARMVIXL::VisitJdkUnsafeCASInt(HInvoke* invoke) {
+  // `jdk.internal.misc.Unsafe.compareAndSwapInt` has compare-and-set semantics (see javadoc).
+  VisitJdkUnsafeCompareAndSetInt(invoke);
+}
+void IntrinsicLocationsBuilderARMVIXL::VisitJdkUnsafeCASObject(HInvoke* invoke) {
+  // `jdk.internal.misc.Unsafe.compareAndSwapObject` has compare-and-set semantics (see javadoc).
+  VisitJdkUnsafeCompareAndSetObject(invoke);
+}
+
+void IntrinsicLocationsBuilderARMVIXL::VisitJdkUnsafeCompareAndSetInt(HInvoke* invoke) {
+  CreateUnsafeCASLocations(allocator_, invoke);
+}
+void IntrinsicLocationsBuilderARMVIXL::VisitJdkUnsafeCompareAndSetObject(HInvoke* invoke) {
+  // The only supported read barrier implementation is the Baker-style read barriers (b/173104084).
+  if (kEmitCompilerReadBarrier && !kUseBakerReadBarrier) {
+    return;
+  }
+
+  CreateUnsafeCASLocations(allocator_, invoke);
+}
+
 void IntrinsicCodeGeneratorARMVIXL::VisitUnsafeCASInt(HInvoke* invoke) {
   VisitJdkUnsafeCASInt(invoke);
 }
@@ -3763,30 +3786,24 @@
   VisitJdkUnsafeCASObject(invoke);
 }
 
-void IntrinsicLocationsBuilderARMVIXL::VisitJdkUnsafeCASInt(HInvoke* invoke) {
-  CreateUnsafeCASLocations(allocator_, invoke);
-}
-void IntrinsicLocationsBuilderARMVIXL::VisitJdkUnsafeCASObject(HInvoke* invoke) {
-  // The only read barrier implementation supporting the
-  // UnsafeCASObject intrinsic is the Baker-style read barriers. b/173104084
-  if (kEmitCompilerReadBarrier && !kUseBakerReadBarrier) {
-    return;
-  }
-
-  CreateUnsafeCASLocations(allocator_, invoke);
-}
-void IntrinsicLocationsBuilderARMVIXL::VisitJdkUnsafeCompareAndSetInt(HInvoke* invoke) {
-  CreateUnsafeCASLocations(allocator_, invoke);
-}
 void IntrinsicCodeGeneratorARMVIXL::VisitJdkUnsafeCASInt(HInvoke* invoke) {
-  GenUnsafeCas(invoke, DataType::Type::kInt32, codegen_);
+  // `jdk.internal.misc.Unsafe.compareAndSwapInt` has compare-and-set semantics (see javadoc).
+  VisitJdkUnsafeCompareAndSetInt(invoke);
 }
 void IntrinsicCodeGeneratorARMVIXL::VisitJdkUnsafeCASObject(HInvoke* invoke) {
-  GenUnsafeCas(invoke, DataType::Type::kReference, codegen_);
+  // `jdk.internal.misc.Unsafe.compareAndSwapObject` has compare-and-set semantics (see javadoc).
+  VisitJdkUnsafeCompareAndSetObject(invoke);
 }
+
 void IntrinsicCodeGeneratorARMVIXL::VisitJdkUnsafeCompareAndSetInt(HInvoke* invoke) {
   GenUnsafeCas(invoke, DataType::Type::kInt32, codegen_);
 }
+void IntrinsicCodeGeneratorARMVIXL::VisitJdkUnsafeCompareAndSetObject(HInvoke* invoke) {
+  // The only supported read barrier implementation is the Baker-style read barriers (b/173104084).
+  DCHECK(!kEmitCompilerReadBarrier || kUseBakerReadBarrier);
+
+  GenUnsafeCas(invoke, DataType::Type::kReference, codegen_);
+}
 
 enum class GetAndUpdateOp {
   kSet,
@@ -5552,7 +5569,6 @@
 UNIMPLEMENTED_INTRINSIC(ARMVIXL, JdkUnsafeGetAndSetLong)
 UNIMPLEMENTED_INTRINSIC(ARMVIXL, JdkUnsafeGetAndSetObject)
 UNIMPLEMENTED_INTRINSIC(ARMVIXL, JdkUnsafeCompareAndSetLong)
-UNIMPLEMENTED_INTRINSIC(ARMVIXL, JdkUnsafeCompareAndSetObject)
 
 UNREACHABLE_INTRINSICS(ARMVIXL)