Avoid read barrier for image HLoadClass
Concurrent copying baker:
X86_64 core-optimizing-pic.oat: 28583112 -> 27906824 (2.4% smaller)
Around 0.4% of 2.4% is from re-enabling kBootImageLinkTimeAddress,
kBootImageLinkTimePcRelative, and kBootImageAddress.
N6P boot.oat 32: 73042140 -> 71891956 (1.57% smaller)
N6P boot.oat 64: 83831608 -> 82531456 (1.55% smaller)
EAAC: 1252 -> 1245 (32 samples)
Bug: 29516974
Test: test-art-host CC baker, N6P booting
Change-Id: I9a196cf0157058836981c43c93872e9f0c4919aa
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 5230269..a21a09e 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -5408,17 +5408,6 @@
HLoadClass::LoadKind CodeGeneratorX86_64::GetSupportedLoadClassKind(
HLoadClass::LoadKind desired_class_load_kind) {
- if (kEmitCompilerReadBarrier) {
- switch (desired_class_load_kind) {
- case HLoadClass::LoadKind::kBootImageLinkTimeAddress:
- case HLoadClass::LoadKind::kBootImageLinkTimePcRelative:
- case HLoadClass::LoadKind::kBootImageAddress:
- // TODO: Implement for read barrier.
- return HLoadClass::LoadKind::kDexCacheViaMethod;
- default:
- break;
- }
- }
switch (desired_class_load_kind) {
case HLoadClass::LoadKind::kReferrersClass:
break;
@@ -5454,11 +5443,12 @@
return;
}
- LocationSummary::CallKind call_kind = (cls->NeedsEnvironment() || kEmitCompilerReadBarrier)
+ const bool requires_read_barrier = kEmitCompilerReadBarrier && !cls->IsInBootImage();
+ LocationSummary::CallKind call_kind = (cls->NeedsEnvironment() || requires_read_barrier)
? LocationSummary::kCallOnSlowPath
: LocationSummary::kNoCall;
LocationSummary* locations = new (GetGraph()->GetArena()) LocationSummary(cls, call_kind);
- if (kUseBakerReadBarrier && !cls->NeedsEnvironment()) {
+ if (kUseBakerReadBarrier && requires_read_barrier && !cls->NeedsEnvironment()) {
locations->SetCustomSlowPathCallerSaves(RegisterSet()); // No caller-save registers.
}
@@ -5482,6 +5472,7 @@
Location out_loc = locations->Out();
CpuRegister out = out_loc.AsRegister<CpuRegister>();
+ const bool requires_read_barrier = kEmitCompilerReadBarrier && !cls->IsInBootImage();
bool generate_null_check = false;
switch (cls->GetLoadKind()) {
case HLoadClass::LoadKind::kReferrersClass: {
@@ -5490,16 +5481,20 @@
// /* GcRoot<mirror::Class> */ out = current_method->declaring_class_
CpuRegister current_method = locations->InAt(0).AsRegister<CpuRegister>();
GenerateGcRootFieldLoad(
- cls, out_loc, Address(current_method, ArtMethod::DeclaringClassOffset().Int32Value()));
+ cls,
+ out_loc,
+ Address(current_method, ArtMethod::DeclaringClassOffset().Int32Value()),
+ /*fixup_label*/nullptr,
+ requires_read_barrier);
break;
}
case HLoadClass::LoadKind::kBootImageLinkTimePcRelative:
- DCHECK(!kEmitCompilerReadBarrier);
+ DCHECK(!requires_read_barrier);
__ leal(out, Address::Absolute(CodeGeneratorX86_64::kDummy32BitOffset, /* no_rip */ false));
codegen_->RecordTypePatch(cls);
break;
case HLoadClass::LoadKind::kBootImageAddress: {
- DCHECK(!kEmitCompilerReadBarrier);
+ DCHECK(!requires_read_barrier);
DCHECK_NE(cls->GetAddress(), 0u);
uint32_t address = dchecked_integral_cast<uint32_t>(cls->GetAddress());
__ movl(out, Immediate(address)); // Zero-extended.
@@ -5511,11 +5506,19 @@
// /* GcRoot<mirror::Class> */ out = *address
if (IsUint<32>(cls->GetAddress())) {
Address address = Address::Absolute(cls->GetAddress(), /* no_rip */ true);
- GenerateGcRootFieldLoad(cls, out_loc, address);
+ GenerateGcRootFieldLoad(cls,
+ out_loc,
+ address,
+ /*fixup_label*/nullptr,
+ requires_read_barrier);
} else {
// TODO: Consider using opcode A1, i.e. movl eax, moff32 (with 64-bit address).
__ movq(out, Immediate(cls->GetAddress()));
- GenerateGcRootFieldLoad(cls, out_loc, Address(out, 0));
+ GenerateGcRootFieldLoad(cls,
+ out_loc,
+ Address(out, 0),
+ /*fixup_label*/nullptr,
+ requires_read_barrier);
}
generate_null_check = !cls->IsInDexCache();
break;
@@ -5526,7 +5529,7 @@
Address address = Address::Absolute(CodeGeneratorX86_64::kDummy32BitOffset,
/* no_rip */ false);
// /* GcRoot<mirror::Class> */ out = *address /* PC-relative */
- GenerateGcRootFieldLoad(cls, out_loc, address, fixup_label);
+ GenerateGcRootFieldLoad(cls, out_loc, address, fixup_label, requires_read_barrier);
generate_null_check = !cls->IsInDexCache();
break;
}
@@ -5539,7 +5542,11 @@
ArtMethod::DexCacheResolvedTypesOffset(kX86_64PointerSize).Int32Value()));
// /* GcRoot<mirror::Class> */ out = out[type_index]
GenerateGcRootFieldLoad(
- cls, out_loc, Address(out, CodeGenerator::GetCacheOffset(cls->GetTypeIndex())));
+ cls,
+ out_loc,
+ Address(out, CodeGenerator::GetCacheOffset(cls->GetTypeIndex())),
+ /*fixup_label*/nullptr,
+ requires_read_barrier);
generate_null_check = !cls->IsInDexCache();
break;
}
@@ -6387,9 +6394,11 @@
void InstructionCodeGeneratorX86_64::GenerateGcRootFieldLoad(HInstruction* instruction,
Location root,
const Address& address,
- Label* fixup_label) {
+ Label* fixup_label,
+ bool requires_read_barrier) {
CpuRegister root_reg = root.AsRegister<CpuRegister>();
- if (kEmitCompilerReadBarrier) {
+ if (requires_read_barrier) {
+ DCHECK(kEmitCompilerReadBarrier);
if (kUseBakerReadBarrier) {
// Fast path implementation of art::ReadBarrier::BarrierForRoot when
// Baker's read barrier are used: