Compile time null checks for VarHandle intrinsics.
Create a `VarHandleOptimizations` helper class holding the
optimization flags for VarHandle intrinsics.
Add a flag to avoid emitting the intrinsic implementation
and move shared checks previously duplicated in intrinsic
codegens helpers `HasVarHandleIntrinsicImplementation()` to
the instruction simplifier. Individual intrinsic codegens
perform additional checks as needed.
Add the first optimization flag to avoid null check on the
holder object if it cannot be null. And do not emit the
intrinsic implementation if the holder object is null.
Test: testrunner.py --host --optimizing
Test: testrunner.py --target --optimizing
Bug: 191765508
Change-Id: I53b1b57c327f02a9913f22885c1ce663cd9c3d44
diff --git a/compiler/optimizing/intrinsics_x86.cc b/compiler/optimizing/intrinsics_x86.cc
index d11bfa2..bed9ebe 100644
--- a/compiler/optimizing/intrinsics_x86.cc
+++ b/compiler/optimizing/intrinsics_x86.cc
@@ -3291,81 +3291,20 @@
__ Bind(slow_path->GetExitLabel());
}
-static bool IsValidFieldVarHandleExpected(HInvoke* invoke) {
+static bool HasVarHandleIntrinsicImplementation(HInvoke* invoke) {
+ VarHandleOptimizations optimizations(invoke);
+ if (optimizations.GetDoNotIntrinsify()) {
+ return false;
+ }
+
size_t expected_coordinates_count = GetExpectedVarHandleCoordinatesCount(invoke);
+ DCHECK_LE(expected_coordinates_count, 2u); // Filtered by the `DoNotIntrinsify` flag above.
if (expected_coordinates_count > 1u) {
// Only static and instance fields VarHandle are supported now.
+ // TODO: add support for arrays and views.
return false;
}
- if (expected_coordinates_count == 1u &&
- invoke->InputAt(1)->GetType() != DataType::Type::kReference) {
- // For instance fields, the source object must be a reference
- return false;
- }
-
- uint32_t number_of_arguments = invoke->GetNumberOfArguments();
- DataType::Type return_type = invoke->GetType();
- mirror::VarHandle::AccessModeTemplate access_mode_template =
- mirror::VarHandle::GetAccessModeTemplateByIntrinsic(invoke->GetIntrinsic());
- switch (access_mode_template) {
- case mirror::VarHandle::AccessModeTemplate::kGet:
- // The return type should be the same as varType, so it shouldn't be void.
- if (return_type == DataType::Type::kVoid) {
- return false;
- }
- break;
- case mirror::VarHandle::AccessModeTemplate::kSet:
- if (return_type != DataType::Type::kVoid) {
- return false;
- }
- break;
- case mirror::VarHandle::AccessModeTemplate::kCompareAndSet: {
- if (return_type != DataType::Type::kBool) {
- return false;
- }
- uint32_t expected_value_index = number_of_arguments - 2;
- uint32_t new_value_index = number_of_arguments - 1;
- DataType::Type expected_value_type = GetDataTypeFromShorty(invoke, expected_value_index);
- DataType::Type new_value_type = GetDataTypeFromShorty(invoke, new_value_index);
-
- if (expected_value_type != new_value_type) {
- return false;
- }
- break;
- }
- case mirror::VarHandle::AccessModeTemplate::kGetAndUpdate: {
- DataType::Type value_type = GetDataTypeFromShorty(invoke, number_of_arguments - 1);
- if (IsVarHandleGetAndAdd(invoke) &&
- (value_type == DataType::Type::kReference || value_type == DataType::Type::kBool)) {
- // We should only add numerical types.
- return false;
- } else if (IsVarHandleGetAndBitwiseOp(invoke) && !DataType::IsIntegralType(value_type)) {
- // We can only apply operators to bitwise integral types.
- // Note that bitwise VarHandle operations accept a non-integral boolean type and
- // perform the appropriate logical operation. However, the result is the same as
- // using the bitwise operation on our boolean representation and this fits well
- // with DataType::IsIntegralType() treating the compiler type kBool as integral.
- return false;
- }
- if (value_type != return_type) {
- return false;
- }
- break;
- }
- case mirror::VarHandle::AccessModeTemplate::kCompareAndExchange: {
- uint32_t expected_value_index = number_of_arguments - 2;
- uint32_t new_value_index = number_of_arguments - 1;
- DataType::Type expected_value_type = GetDataTypeFromShorty(invoke, expected_value_index);
- DataType::Type new_value_type = GetDataTypeFromShorty(invoke, new_value_index);
-
- if (expected_value_type != new_value_type || return_type != expected_value_type) {
- return false;
- }
- break;
- }
- }
-
return true;
}
@@ -3426,11 +3365,15 @@
__ Bind(&type_matched);
}
-static void GenerateVarHandleInstanceFieldObjectCheck(Register varhandle_object,
- Register object,
- Register temp,
- SlowPathCode* slow_path,
- X86Assembler* assembler) {
+static void GenerateVarHandleInstanceFieldChecks(HInvoke* invoke,
+ Register temp,
+ SlowPathCode* slow_path,
+ X86Assembler* assembler) {
+ VarHandleOptimizations optimizations(invoke);
+ LocationSummary* locations = invoke->GetLocations();
+ Register varhandle_object = locations->InAt(0).AsRegister<Register>();
+ Register object = locations->InAt(1).AsRegister<Register>();
+
const uint32_t coordtype0_offset = mirror::VarHandle::CoordinateType0Offset().Uint32Value();
const uint32_t coordtype1_offset = mirror::VarHandle::CoordinateType1Offset().Uint32Value();
@@ -3441,8 +3384,10 @@
__ j(kNotEqual, slow_path->GetEntryLabel());
// Check if the object is null
- __ testl(object, object);
- __ j(kZero, slow_path->GetEntryLabel());
+ if (!optimizations.GetSkipObjectNullCheck()) {
+ __ testl(object, object);
+ __ j(kZero, slow_path->GetEntryLabel());
+ }
// Check the object's class against coordinateType0.
GenerateSubTypeObjectCheck(object,
@@ -3490,8 +3435,7 @@
GenerateVarHandleStaticFieldCheck(vh_object, slow_path, assembler);
break;
case 1u: {
- Register object = locations->InAt(1).AsRegister<Register>();
- GenerateVarHandleInstanceFieldObjectCheck(vh_object, object, temp, slow_path, assembler);
+ GenerateVarHandleInstanceFieldChecks(invoke, temp, slow_path, assembler);
break;
}
default:
@@ -3603,7 +3547,7 @@
return;
}
- if (!IsValidFieldVarHandleExpected(invoke)) {
+ if (!HasVarHandleIntrinsicImplementation(invoke)) {
return;
}
@@ -3726,7 +3670,7 @@
return;
}
- if (!IsValidFieldVarHandleExpected(invoke)) {
+ if (!HasVarHandleIntrinsicImplementation(invoke)) {
return;
}
@@ -3896,7 +3840,7 @@
return;
}
- if (!IsValidFieldVarHandleExpected(invoke)) {
+ if (!HasVarHandleIntrinsicImplementation(invoke)) {
return;
}
@@ -4067,7 +4011,7 @@
return;
}
- if (!IsValidFieldVarHandleExpected(invoke)) {
+ if (!HasVarHandleIntrinsicImplementation(invoke)) {
return;
}
@@ -4250,7 +4194,7 @@
return;
}
- if (!IsValidFieldVarHandleExpected(invoke)) {
+ if (!HasVarHandleIntrinsicImplementation(invoke)) {
return;
}
@@ -4400,7 +4344,7 @@
return;
}
- if (!IsValidFieldVarHandleExpected(invoke)) {
+ if (!HasVarHandleIntrinsicImplementation(invoke)) {
return;
}