X86: Add the other variants of VarHandle.compareAndSet

This commit implements VarHandle WeakCompareAndSet,
WeakCompareAndSetPlain, WeakCompareAndSetAcquire,
WeakCompareAndSetRelease.

Test: art/test.py --host -r -t 712-varhandle-invocation --32
Change-Id: I1e0f5e7dcb21cd0f107d5a74cb534cef992ef9fc

2 files changed, 59 insertions, 16 deletions

diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index 4a0eb2e42e..1a83976d60 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -33,6 +33,7 @@
 #include "lock_word.h"
 #include "mirror/array-inl.h"
 #include "mirror/class-inl.h"
+#include "mirror/var_handle.h"
 #include "scoped_thread_state_change-inl.h"
 #include "thread.h"
 #include "utils/assembler.h"
@@ -572,8 +573,10 @@ class ReadBarrierMarkAndUpdateFieldSlowPathX86 : public SlowPathCode {
         << "Unexpected instruction in read barrier marking and field updating slow path: "
         << instruction_->DebugName();
     DCHECK(instruction_->GetLocations()->Intrinsified());
-    DCHECK(instruction_->AsInvoke()->GetIntrinsic() == Intrinsics::kUnsafeCASObject ||
-           instruction_->AsInvoke()->GetIntrinsic() == Intrinsics::kVarHandleCompareAndSet);
+    Intrinsics intrinsic = instruction_->AsInvoke()->GetIntrinsic();
+    static constexpr auto kVarHandleCAS = mirror::VarHandle::AccessModeTemplate::kCompareAndSet;
+    DCHECK(intrinsic == Intrinsics::kUnsafeCASObject ||
+           mirror::VarHandle::GetAccessModeTemplateByIntrinsic(intrinsic) == kVarHandleCAS);
 
     __ Bind(GetEntryLabel());
     if (unpoison_ref_before_marking_) {
diff --git a/compiler/optimizing/intrinsics_x86.cc b/compiler/optimizing/intrinsics_x86.cc
index f10b5112f9..1c1b4ea62e 100644
--- a/compiler/optimizing/intrinsics_x86.cc
+++ b/compiler/optimizing/intrinsics_x86.cc
@@ -3572,7 +3572,7 @@ void IntrinsicCodeGeneratorX86::VisitVarHandleSet(HInvoke* invoke) {
   __ Bind(slow_path->GetExitLabel());
 }
 
-void IntrinsicLocationsBuilderX86::VisitVarHandleCompareAndSet(HInvoke* invoke) {
+static void CreateVarHandleCompareAndSetLocations(HInvoke* invoke) {
   // The only read barrier implementation supporting the
   // VarHandleGet intrinsic is the Baker-style read barriers.
   if (kEmitCompilerReadBarrier && !kUseBakerReadBarrier) {
@@ -3598,7 +3598,8 @@ void IntrinsicLocationsBuilderX86::VisitVarHandleCompareAndSet(HInvoke* invoke)
     return;
   }
 
-  LocationSummary* locations = new (allocator_) LocationSummary(
+  ArenaAllocator* allocator = invoke->GetBlock()->GetGraph()->GetAllocator();
+  LocationSummary* locations = new (allocator) LocationSummary(
       invoke, LocationSummary::kCallOnSlowPath, kIntrinsified);
   locations->AddTemp(Location::RequiresRegister());
   locations->AddTemp(Location::RequiresRegister());
@@ -3628,12 +3629,12 @@ void IntrinsicLocationsBuilderX86::VisitVarHandleCompareAndSet(HInvoke* invoke)
   locations->SetOut(Location::RegisterLocation(EAX));
 }
 
-void IntrinsicCodeGeneratorX86::VisitVarHandleCompareAndSet(HInvoke* invoke) {
+static void GenerateVarHandleCompareAndSet(HInvoke* invoke, CodeGeneratorX86* codegen) {
   // The only read barrier implementation supporting the
   // VarHandleGet intrinsic is the Baker-style read barriers.
   DCHECK(!kEmitCompilerReadBarrier || kUseBakerReadBarrier);
 
-  X86Assembler* assembler = codegen_->GetAssembler();
+  X86Assembler* assembler = codegen->GetAssembler();
   LocationSummary* locations = invoke->GetLocations();
   uint32_t number_of_arguments = invoke->GetNumberOfArguments();
   uint32_t expected_value_index = number_of_arguments - 2;
@@ -3646,8 +3647,8 @@ void IntrinsicCodeGeneratorX86::VisitVarHandleCompareAndSet(HInvoke* invoke) {
   Register offset = locations->GetTemp(0).AsRegister<Register>();
   Register temp = locations->GetTemp(1).AsRegister<Register>();
   Register temp2 = locations->GetTemp(2).AsRegister<Register>();
-  SlowPathCode* slow_path = new (codegen_->GetScopedAllocator()) IntrinsicSlowPathX86(invoke);
-  codegen_->AddSlowPath(slow_path);
+  SlowPathCode* slow_path = new (codegen->GetScopedAllocator()) IntrinsicSlowPathX86(invoke);
+  codegen->AddSlowPath(slow_path);
 
   GenerateVarHandleCommonChecks(invoke, temp, slow_path, assembler);
   // Check the varType.primitiveType against the type of the expected value.
@@ -3672,7 +3673,7 @@ void IntrinsicCodeGeneratorX86::VisitVarHandleCompareAndSet(HInvoke* invoke) {
   // Get the field referred by the VarHandle. The returned register contains the object reference
   // or the declaring class. The field offset will be placed in 'offset'. For static fields, the
   // declaring class will be placed in 'temp' register.
-  Register reference = GenerateVarHandleFieldReference(invoke, codegen_, temp, offset);
+  Register reference = GenerateVarHandleFieldReference(invoke, codegen, temp, offset);
 
   uint32_t expected_coordinates_count = GetExpectedVarHandleCoordinatesCount(invoke);
   // For generating the compare and exchange, we need 2 temporaries. In case of a static field, the
@@ -3681,17 +3682,60 @@ void IntrinsicCodeGeneratorX86::VisitVarHandleCompareAndSet(HInvoke* invoke) {
   temp = (expected_coordinates_count == 1u) ? temp : locations->GetTemp(3).AsRegister<Register>();
   DCHECK_NE(temp, reference);
 
+  // We are using `lock cmpxchg` in all cases because there is no CAS equivalent that has weak
+  // failure semantics. `lock cmpxchg` has full barrier semantics, and we don't need scheduling
+  // barriers at this time.
+
   if (type == DataType::Type::kReference) {
-    GenReferenceCAS(invoke, codegen_, expected_value, new_value, reference, offset, temp, temp2);
+    GenReferenceCAS(invoke, codegen, expected_value, new_value, reference, offset, temp, temp2);
   } else {
     Location out = locations->Out();
-    GenPrimitiveCAS(type, codegen_, expected_value, new_value, reference, offset, out, temp);
+    GenPrimitiveCAS(type, codegen, expected_value, new_value, reference, offset, out, temp);
   }
 
-  codegen_->GenerateMemoryBarrier(MemBarrierKind::kAnyAny);
   __ Bind(slow_path->GetExitLabel());
 }
 
+void IntrinsicLocationsBuilderX86::VisitVarHandleCompareAndSet(HInvoke* invoke) {
+  CreateVarHandleCompareAndSetLocations(invoke);
+}
+
+void IntrinsicCodeGeneratorX86::VisitVarHandleCompareAndSet(HInvoke* invoke) {
+  GenerateVarHandleCompareAndSet(invoke, codegen_);
+}
+
+void IntrinsicLocationsBuilderX86::VisitVarHandleWeakCompareAndSet(HInvoke* invoke) {
+  CreateVarHandleCompareAndSetLocations(invoke);
+}
+
+void IntrinsicCodeGeneratorX86::VisitVarHandleWeakCompareAndSet(HInvoke* invoke) {
+  GenerateVarHandleCompareAndSet(invoke, codegen_);
+}
+
+void IntrinsicLocationsBuilderX86::VisitVarHandleWeakCompareAndSetPlain(HInvoke* invoke) {
+  CreateVarHandleCompareAndSetLocations(invoke);
+}
+
+void IntrinsicCodeGeneratorX86::VisitVarHandleWeakCompareAndSetPlain(HInvoke* invoke) {
+  GenerateVarHandleCompareAndSet(invoke, codegen_);
+}
+
+void IntrinsicLocationsBuilderX86::VisitVarHandleWeakCompareAndSetAcquire(HInvoke* invoke) {
+  CreateVarHandleCompareAndSetLocations(invoke);
+}
+
+void IntrinsicCodeGeneratorX86::VisitVarHandleWeakCompareAndSetAcquire(HInvoke* invoke) {
+  GenerateVarHandleCompareAndSet(invoke, codegen_);
+}
+
+void IntrinsicLocationsBuilderX86::VisitVarHandleWeakCompareAndSetRelease(HInvoke* invoke) {
+  CreateVarHandleCompareAndSetLocations(invoke);
+}
+
+void IntrinsicCodeGeneratorX86::VisitVarHandleWeakCompareAndSetRelease(HInvoke* invoke) {
+  GenerateVarHandleCompareAndSet(invoke, codegen_);
+}
+
 UNIMPLEMENTED_INTRINSIC(X86, MathRoundDouble)
 UNIMPLEMENTED_INTRINSIC(X86, ReferenceGetReferent)
 UNIMPLEMENTED_INTRINSIC(X86, FloatIsInfinite)
@@ -3767,10 +3811,6 @@ UNIMPLEMENTED_INTRINSIC(X86, VarHandleGetVolatile)
 UNIMPLEMENTED_INTRINSIC(X86, VarHandleSetOpaque)
 UNIMPLEMENTED_INTRINSIC(X86, VarHandleSetRelease)
 UNIMPLEMENTED_INTRINSIC(X86, VarHandleSetVolatile)
-UNIMPLEMENTED_INTRINSIC(X86, VarHandleWeakCompareAndSet)
-UNIMPLEMENTED_INTRINSIC(X86, VarHandleWeakCompareAndSetAcquire)
-UNIMPLEMENTED_INTRINSIC(X86, VarHandleWeakCompareAndSetPlain)
-UNIMPLEMENTED_INTRINSIC(X86, VarHandleWeakCompareAndSetRelease)
 
 UNREACHABLE_INTRINSICS(X86)