Improve HLoadClass code generation.
For classes in the boot image, use either direct pointers
or PC-relative addresses. For other classes, use PC-relative
access to the dex cache arrays for AOT and direct address of
the type's dex cache slot for JIT.
For aosp_flounder-userdebug:
- 32-bit boot.oat: -252KiB (-0.3%)
- 64-bit boot.oat: -412KiB (-0.4%)
- 32-bit dalvik cache total: -392KiB (-0.4%)
- 64-bit dalvik-cache total: -2312KiB (-1.0%)
(contains more files than the 32-bit dalvik cache)
For aosp_flounder-userdebug forced to compile PIC:
- 32-bit boot.oat: -124KiB (-0.2%)
- 64-bit boot.oat: -420KiB (-0.5%)
- 32-bit dalvik cache total: -136KiB (-0.1%)
- 64-bit dalvik-cache total: -1136KiB (-0.5%)
(contains more files than the 32-bit dalvik cache)
Bug: 27950288
Change-Id: I4da991a4b7e53c63c92558b97923d18092acf139
diff --git a/compiler/optimizing/sharpening.cc b/compiler/optimizing/sharpening.cc
index 08bd35f..97f34e6 100644
--- a/compiler/optimizing/sharpening.cc
+++ b/compiler/optimizing/sharpening.cc
@@ -40,13 +40,14 @@
HInstruction* instruction = it.Current();
if (instruction->IsInvokeStaticOrDirect()) {
ProcessInvokeStaticOrDirect(instruction->AsInvokeStaticOrDirect());
+ } else if (instruction->IsLoadClass()) {
+ ProcessLoadClass(instruction->AsLoadClass());
} else if (instruction->IsLoadString()) {
ProcessLoadString(instruction->AsLoadString());
}
// TODO: Move the sharpening of invoke-virtual/-interface/-super from HGraphBuilder
// here. Rewrite it to avoid the CompilerDriver's reliance on verifier data
// because we know the type better when inlining.
- // TODO: HLoadClass - select better load kind if available.
}
}
}
@@ -153,6 +154,123 @@
invoke->SetDispatchInfo(dispatch_info);
}
+void HSharpening::ProcessLoadClass(HLoadClass* load_class) {
+ if (load_class->NeedsAccessCheck()) {
+ // We need to call the runtime anyway, so we simply get the class as that call's return value.
+ return;
+ }
+ if (load_class->GetLoadKind() == HLoadClass::LoadKind::kReferrersClass) {
+ // Loading from the ArtMethod* is the most efficient retrieval.
+ // TODO: This may not actually be true for all architectures and
+ // locations of target classes. The additional register pressure
+ // for using the ArtMethod* should be considered.
+ return;
+ }
+
+ DCHECK_EQ(load_class->GetLoadKind(), HLoadClass::LoadKind::kDexCacheViaMethod);
+ DCHECK(!load_class->IsInDexCache()) << "HLoadClass should not be optimized before sharpening.";
+
+ const DexFile& dex_file = load_class->GetDexFile();
+ uint32_t type_index = load_class->GetTypeIndex();
+
+ bool is_in_dex_cache = false;
+ HLoadClass::LoadKind desired_load_kind;
+ uint64_t address = 0u; // Class or dex cache element address.
+ {
+ ScopedObjectAccess soa(Thread::Current());
+ StackHandleScope<1> hs(soa.Self());
+ Runtime* runtime = Runtime::Current();
+ ClassLinker* class_linker = runtime->GetClassLinker();
+ Handle<mirror::DexCache> dex_cache = IsSameDexFile(dex_file, *compilation_unit_.GetDexFile())
+ ? compilation_unit_.GetDexCache()
+ : hs.NewHandle(class_linker->FindDexCache(soa.Self(), dex_file));
+ mirror::Class* klass = dex_cache->GetResolvedType(type_index);
+
+ if (compiler_driver_->IsBootImage()) {
+ // Compiling boot image. Check if the class is a boot image class.
+ DCHECK(!runtime->UseJitCompilation());
+ if (!compiler_driver_->GetSupportBootImageFixup()) {
+ // MIPS/MIPS64 or compiler_driver_test. Do not sharpen.
+ desired_load_kind = HLoadClass::LoadKind::kDexCacheViaMethod;
+ } else {
+ if (klass != nullptr &&
+ compiler_driver_->IsImageClass(
+ dex_file.StringDataByIdx(dex_file.GetTypeId(type_index).descriptor_idx_))) {
+ is_in_dex_cache = true;
+ desired_load_kind = codegen_->GetCompilerOptions().GetCompilePic()
+ ? HLoadClass::LoadKind::kBootImageLinkTimePcRelative
+ : HLoadClass::LoadKind::kBootImageLinkTimeAddress;
+ } else {
+ // Not a boot image class. We must go through the dex cache.
+ DCHECK(ContainsElement(compiler_driver_->GetDexFilesForOatFile(), &dex_file));
+ desired_load_kind = HLoadClass::LoadKind::kDexCachePcRelative;
+ }
+ }
+ } else if (runtime->UseJitCompilation()) {
+ // TODO: Make sure we don't set the "compile PIC" flag for JIT as that's bogus.
+ // DCHECK(!codegen_->GetCompilerOptions().GetCompilePic());
+ is_in_dex_cache = (klass != nullptr);
+ if (klass != nullptr && runtime->GetHeap()->ObjectIsInBootImageSpace(klass)) {
+ // TODO: Use direct pointers for all non-moving spaces, not just boot image. Bug: 29530787
+ desired_load_kind = HLoadClass::LoadKind::kBootImageAddress;
+ address = reinterpret_cast64<uint64_t>(klass);
+ } else {
+ // Note: If the class is not in the dex cache or isn't initialized, the
+ // instruction needs environment and will not be inlined across dex files.
+ // Within a dex file, the slow-path helper loads the correct class and
+ // inlined frames are used correctly for OOM stack trace.
+ // TODO: Write a test for this. Bug: 29416588
+ desired_load_kind = HLoadClass::LoadKind::kDexCacheAddress;
+ void* dex_cache_element_address = &dex_cache->GetResolvedTypes()[type_index];
+ address = reinterpret_cast64<uint64_t>(dex_cache_element_address);
+ }
+ } else {
+ // AOT app compilation. Check if the class is in the boot image.
+ if ((klass != nullptr) &&
+ runtime->GetHeap()->ObjectIsInBootImageSpace(klass) &&
+ !codegen_->GetCompilerOptions().GetCompilePic()) {
+ desired_load_kind = HLoadClass::LoadKind::kBootImageAddress;
+ address = reinterpret_cast64<uint64_t>(klass);
+ } else {
+ // Not JIT and either the klass is not in boot image or we are compiling in PIC mode.
+ // Use PC-relative load from the dex cache if the dex file belongs
+ // to the oat file that we're currently compiling.
+ desired_load_kind =
+ ContainsElement(compiler_driver_->GetDexFilesForOatFile(), &load_class->GetDexFile())
+ ? HLoadClass::LoadKind::kDexCachePcRelative
+ : HLoadClass::LoadKind::kDexCacheViaMethod;
+ }
+ }
+ }
+ if (is_in_dex_cache) {
+ load_class->MarkInDexCache();
+ }
+
+ HLoadClass::LoadKind load_kind = codegen_->GetSupportedLoadClassKind(desired_load_kind);
+ switch (load_kind) {
+ case HLoadClass::LoadKind::kBootImageLinkTimeAddress:
+ case HLoadClass::LoadKind::kBootImageLinkTimePcRelative:
+ case HLoadClass::LoadKind::kDexCacheViaMethod:
+ load_class->SetLoadKindWithTypeReference(load_kind, dex_file, type_index);
+ break;
+ case HLoadClass::LoadKind::kBootImageAddress:
+ case HLoadClass::LoadKind::kDexCacheAddress:
+ DCHECK_NE(address, 0u);
+ load_class->SetLoadKindWithAddress(load_kind, address);
+ break;
+ case HLoadClass::LoadKind::kDexCachePcRelative: {
+ size_t pointer_size = InstructionSetPointerSize(codegen_->GetInstructionSet());
+ DexCacheArraysLayout layout(pointer_size, &dex_file);
+ size_t element_index = layout.TypeOffset(type_index);
+ load_class->SetLoadKindWithDexCacheReference(load_kind, dex_file, element_index);
+ break;
+ }
+ default:
+ LOG(FATAL) << "Unexpected load kind: " << load_kind;
+ UNREACHABLE();
+ }
+}
+
void HSharpening::ProcessLoadString(HLoadString* load_string) {
DCHECK_EQ(load_string->GetLoadKind(), HLoadString::LoadKind::kDexCacheViaMethod);
DCHECK(!load_string->IsInDexCache());
@@ -193,13 +311,14 @@
mirror::String* string = dex_cache->GetResolvedString(string_index);
is_in_dex_cache = (string != nullptr);
if (string != nullptr && runtime->GetHeap()->ObjectIsInBootImageSpace(string)) {
+ // TODO: Use direct pointers for all non-moving spaces, not just boot image. Bug: 29530787
desired_load_kind = HLoadString::LoadKind::kBootImageAddress;
address = reinterpret_cast64<uint64_t>(string);
} else {
// Note: If the string is not in the dex cache, the instruction needs environment
// and will not be inlined across dex files. Within a dex file, the slow-path helper
// loads the correct string and inlined frames are used correctly for OOM stack trace.
- // TODO: Write a test for this.
+ // TODO: Write a test for this. Bug: 29416588
desired_load_kind = HLoadString::LoadKind::kDexCacheAddress;
void* dex_cache_element_address = &dex_cache->GetStrings()[string_index];
address = reinterpret_cast64<uint64_t>(dex_cache_element_address);
@@ -207,20 +326,18 @@
} else {
// AOT app compilation. Try to lookup the string without allocating if not found.
mirror::String* string = class_linker->LookupString(dex_file, string_index, dex_cache);
- if (string != nullptr && runtime->GetHeap()->ObjectIsInBootImageSpace(string)) {
- if (codegen_->GetCompilerOptions().GetCompilePic()) {
- // Use PC-relative load from the dex cache if the dex file belongs
- // to the oat file that we're currently compiling.
- desired_load_kind = ContainsElement(compiler_driver_->GetDexFilesForOatFile(), &dex_file)
- ? HLoadString::LoadKind::kDexCachePcRelative
- : HLoadString::LoadKind::kDexCacheViaMethod;
- } else {
- desired_load_kind = HLoadString::LoadKind::kBootImageAddress;
- address = reinterpret_cast64<uint64_t>(string);
- }
+ if (string != nullptr &&
+ runtime->GetHeap()->ObjectIsInBootImageSpace(string) &&
+ !codegen_->GetCompilerOptions().GetCompilePic()) {
+ desired_load_kind = HLoadString::LoadKind::kBootImageAddress;
+ address = reinterpret_cast64<uint64_t>(string);
} else {
- // Not JIT and the string is not in boot image.
- desired_load_kind = HLoadString::LoadKind::kDexCachePcRelative;
+ // Not JIT and either the string is not in boot image or we are compiling in PIC mode.
+ // Use PC-relative load from the dex cache if the dex file belongs
+ // to the oat file that we're currently compiling.
+ desired_load_kind = ContainsElement(compiler_driver_->GetDexFilesForOatFile(), &dex_file)
+ ? HLoadString::LoadKind::kDexCachePcRelative
+ : HLoadString::LoadKind::kDexCacheViaMethod;
}
}
}