Clean up InstanceOf/CheckCast.
Avoid read barriers for boot image class InstanceOf. Boot
image classes are non-moveable, so comparing them against
from-space and to-space reference yields the same result.
Change the notion of a "fatal" type check slow path to mean
that the runtime call shall not return by normal path, i.e.
"fatal" now includes certainly throwing in a try-block. This
avoids unnecessary code to restore registers and jump back.
For boot image classes the CheckCast comparisons do not need
read barriers (for the same reason as for InstanceOf), so we
shall not have any false negatives and can treat the check's
slow paths as final in the same cases as in non-CC configs.
Boot image size for aosp_taimen-userdebug in AOSP master:
- before:
arm boot*.oat: 37075460
arm64 boot*.oat: 43431768
- after:
arm boot*.oat: 36894292 (-177KiB, -0.5%)
arm64 boot*.oat: 43201256 (-225KiB, -0.5%)
Also remove some obsolete helpers from CodeGenerator.
Test: Additional test in 603-checker-instanceof.
Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Test: Pixel 2 XL boots.
Test: testrunner.py --target --optimizing
Bug: 12687968
Change-Id: Ib1381084e46a10e70320dcc618f0502ad725f0b8
diff --git a/compiler/optimizing/code_generator_arm_vixl.cc b/compiler/optimizing/code_generator_arm_vixl.cc
index 3f8f0c4..017598d 100644
--- a/compiler/optimizing/code_generator_arm_vixl.cc
+++ b/compiler/optimizing/code_generator_arm_vixl.cc
@@ -619,7 +619,7 @@
CodeGeneratorARMVIXL* arm_codegen = down_cast<CodeGeneratorARMVIXL*>(codegen);
__ Bind(GetEntryLabel());
- if (!is_fatal_) {
+ if (!is_fatal_ || instruction_->CanThrowIntoCatchBlock()) {
SaveLiveRegisters(codegen, locations);
}
@@ -7377,11 +7377,12 @@
case TypeCheckKind::kExactCheck:
case TypeCheckKind::kAbstractClassCheck:
case TypeCheckKind::kClassHierarchyCheck:
- case TypeCheckKind::kArrayObjectCheck:
- call_kind =
- kEmitCompilerReadBarrier ? LocationSummary::kCallOnSlowPath : LocationSummary::kNoCall;
- baker_read_barrier_slow_path = kUseBakerReadBarrier;
+ case TypeCheckKind::kArrayObjectCheck: {
+ bool needs_read_barrier = CodeGenerator::InstanceOfNeedsReadBarrier(instruction);
+ call_kind = needs_read_barrier ? LocationSummary::kCallOnSlowPath : LocationSummary::kNoCall;
+ baker_read_barrier_slow_path = kUseBakerReadBarrier && needs_read_barrier;
break;
+ }
case TypeCheckKind::kArrayCheck:
case TypeCheckKind::kUnresolvedCheck:
case TypeCheckKind::kInterfaceCheck:
@@ -7434,13 +7435,15 @@
switch (type_check_kind) {
case TypeCheckKind::kExactCheck: {
+ ReadBarrierOption read_barrier_option =
+ CodeGenerator::ReadBarrierOptionForInstanceOf(instruction);
// /* HeapReference<Class> */ out = obj->klass_
GenerateReferenceLoadTwoRegisters(instruction,
out_loc,
obj_loc,
class_offset,
maybe_temp_loc,
- kCompilerReadBarrierOption);
+ read_barrier_option);
// Classes must be equal for the instanceof to succeed.
__ Cmp(out, cls);
// We speculatively set the result to false without changing the condition
@@ -7467,13 +7470,15 @@
}
case TypeCheckKind::kAbstractClassCheck: {
+ ReadBarrierOption read_barrier_option =
+ CodeGenerator::ReadBarrierOptionForInstanceOf(instruction);
// /* HeapReference<Class> */ out = obj->klass_
GenerateReferenceLoadTwoRegisters(instruction,
out_loc,
obj_loc,
class_offset,
maybe_temp_loc,
- kCompilerReadBarrierOption);
+ read_barrier_option);
// If the class is abstract, we eagerly fetch the super class of the
// object to avoid doing a comparison we know will fail.
vixl32::Label loop;
@@ -7483,7 +7488,7 @@
out_loc,
super_offset,
maybe_temp_loc,
- kCompilerReadBarrierOption);
+ read_barrier_option);
// If `out` is null, we use it for the result, and jump to the final label.
__ CompareAndBranchIfZero(out, final_label, /* far_target */ false);
__ Cmp(out, cls);
@@ -7493,13 +7498,15 @@
}
case TypeCheckKind::kClassHierarchyCheck: {
+ ReadBarrierOption read_barrier_option =
+ CodeGenerator::ReadBarrierOptionForInstanceOf(instruction);
// /* HeapReference<Class> */ out = obj->klass_
GenerateReferenceLoadTwoRegisters(instruction,
out_loc,
obj_loc,
class_offset,
maybe_temp_loc,
- kCompilerReadBarrierOption);
+ read_barrier_option);
// Walk over the class hierarchy to find a match.
vixl32::Label loop, success;
__ Bind(&loop);
@@ -7510,7 +7517,7 @@
out_loc,
super_offset,
maybe_temp_loc,
- kCompilerReadBarrierOption);
+ read_barrier_option);
// This is essentially a null check, but it sets the condition flags to the
// proper value for the code that follows the loop, i.e. not `eq`.
__ Cmp(out, 1);
@@ -7547,13 +7554,15 @@
}
case TypeCheckKind::kArrayObjectCheck: {
+ ReadBarrierOption read_barrier_option =
+ CodeGenerator::ReadBarrierOptionForInstanceOf(instruction);
// /* HeapReference<Class> */ out = obj->klass_
GenerateReferenceLoadTwoRegisters(instruction,
out_loc,
obj_loc,
class_offset,
maybe_temp_loc,
- kCompilerReadBarrierOption);
+ read_barrier_option);
// Do an exact check.
vixl32::Label exact_check;
__ Cmp(out, cls);
@@ -7564,7 +7573,7 @@
out_loc,
component_offset,
maybe_temp_loc,
- kCompilerReadBarrierOption);
+ read_barrier_option);
// If `out` is null, we use it for the result, and jump to the final label.
__ CompareAndBranchIfZero(out, final_label, /* far_target */ false);
GetAssembler()->LoadFromOffset(kLoadUnsignedHalfword, out, out, primitive_offset);
@@ -7654,26 +7663,8 @@
}
void LocationsBuilderARMVIXL::VisitCheckCast(HCheckCast* instruction) {
- LocationSummary::CallKind call_kind = LocationSummary::kNoCall;
- bool throws_into_catch = instruction->CanThrowIntoCatchBlock();
-
TypeCheckKind type_check_kind = instruction->GetTypeCheckKind();
- switch (type_check_kind) {
- case TypeCheckKind::kExactCheck:
- case TypeCheckKind::kAbstractClassCheck:
- case TypeCheckKind::kClassHierarchyCheck:
- case TypeCheckKind::kArrayObjectCheck:
- call_kind = (throws_into_catch || kEmitCompilerReadBarrier) ?
- LocationSummary::kCallOnSlowPath :
- LocationSummary::kNoCall; // In fact, call on a fatal (non-returning) slow path.
- break;
- case TypeCheckKind::kArrayCheck:
- case TypeCheckKind::kUnresolvedCheck:
- case TypeCheckKind::kInterfaceCheck:
- call_kind = LocationSummary::kCallOnSlowPath;
- break;
- }
-
+ LocationSummary::CallKind call_kind = CodeGenerator::GetCheckCastCallKind(instruction);
LocationSummary* locations =
new (GetGraph()->GetAllocator()) LocationSummary(instruction, call_kind);
locations->SetInAt(0, Location::RequiresRegister());
@@ -7702,18 +7693,7 @@
const uint32_t object_array_data_offset =
mirror::Array::DataOffset(kHeapReferenceSize).Uint32Value();
- // Always false for read barriers since we may need to go to the entrypoint for non-fatal cases
- // from false negatives. The false negatives may come from avoiding read barriers below. Avoiding
- // read barriers is done for performance and code size reasons.
- bool is_type_check_slow_path_fatal = false;
- if (!kEmitCompilerReadBarrier) {
- is_type_check_slow_path_fatal =
- (type_check_kind == TypeCheckKind::kExactCheck ||
- type_check_kind == TypeCheckKind::kAbstractClassCheck ||
- type_check_kind == TypeCheckKind::kClassHierarchyCheck ||
- type_check_kind == TypeCheckKind::kArrayObjectCheck) &&
- !instruction->CanThrowIntoCatchBlock();
- }
+ bool is_type_check_slow_path_fatal = CodeGenerator::IsTypeCheckSlowPathFatal(instruction);
SlowPathCodeARMVIXL* type_check_slow_path =
new (codegen_->GetScopedAllocator()) TypeCheckSlowPathARMVIXL(
instruction, is_type_check_slow_path_fatal);