/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "sharpening.h"
#include "art_method-inl.h"
#include "base/casts.h"
#include "base/enums.h"
#include "class_linker.h"
#include "code_generator.h"
#include "driver/compiler_options.h"
#include "driver/dex_compilation_unit.h"
#include "gc/heap.h"
#include "gc/space/image_space.h"
#include "handle_scope-inl.h"
#include "mirror/dex_cache.h"
#include "mirror/string.h"
#include "nodes.h"
#include "runtime.h"
#include "scoped_thread_state_change-inl.h"
#include "utils/dex_cache_arrays_layout-inl.h"
namespace art {
static bool IsInBootImage(ArtMethod* method) {
const std::vector<gc::space::ImageSpace*>& image_spaces =
Runtime::Current()->GetHeap()->GetBootImageSpaces();
for (gc::space::ImageSpace* image_space : image_spaces) {
const ImageSection& method_section = image_space->GetImageHeader().GetMethodsSection();
if (method_section.Contains(reinterpret_cast<uint8_t*>(method) - image_space->Begin())) {
return true;
}
}
return false;
}
static bool BootImageAOTCanEmbedMethod(ArtMethod* method, const CompilerOptions& compiler_options) {
DCHECK(compiler_options.IsBootImage());
ScopedObjectAccess soa(Thread::Current());
ObjPtr<mirror::Class> klass = method->GetDeclaringClass();
DCHECK(klass != nullptr);
const DexFile& dex_file = klass->GetDexFile();
return compiler_options.IsImageClass(dex_file.StringByTypeIdx(klass->GetDexTypeIndex()));
}
HInvokeStaticOrDirect::DispatchInfo HSharpening::SharpenInvokeStaticOrDirect(
ArtMethod* callee, CodeGenerator* codegen) {
if (kIsDebugBuild) {
ScopedObjectAccess soa(Thread::Current()); // Required for GetDeclaringClass below.
DCHECK(callee != nullptr);
DCHECK(!(callee->IsConstructor() && callee->GetDeclaringClass()->IsStringClass()));
}
HInvokeStaticOrDirect::MethodLoadKind method_load_kind;
HInvokeStaticOrDirect::CodePtrLocation code_ptr_location;
uint64_t method_load_data = 0u;
// Note: we never call an ArtMethod through a known code pointer, as
// we do not want to keep on invoking it if it gets deoptimized. This
// applies to both AOT and JIT.
// This also avoids having to find out if the code pointer of an ArtMethod
// is the resolution trampoline (for ensuring the class is initialized), or
// the interpreter entrypoint. Such code pointers we do not want to call
// directly.
// Only in the case of a recursive call can we call directly, as we know the
// class is initialized already or being initialized, and the call will not
// be invoked once the method is deoptimized.
// We don't optimize for debuggable as it would prevent us from obsoleting the method in some
// situations.
const CompilerOptions& compiler_options = codegen->GetCompilerOptions();
if (callee == codegen->GetGraph()->GetArtMethod() && !codegen->GetGraph()->IsDebuggable()) {
// Recursive call.
method_load_kind = HInvokeStaticOrDirect::MethodLoadKind::kRecursive;
code_ptr_location = HInvokeStaticOrDirect::CodePtrLocation::kCallSelf;
} else if (compiler_options.IsBootImage()) {
if (!compiler_options.GetCompilePic()) {
// Test configuration, do not sharpen.
method_load_kind = HInvokeStaticOrDirect::MethodLoadKind::kRuntimeCall;
} else if (BootImageAOTCanEmbedMethod(callee, compiler_options)) {
method_load_kind = HInvokeStaticOrDirect::MethodLoadKind::kBootImageLinkTimePcRelative;
} else {
// Use PC-relative access to the .bss methods array.
method_load_kind = HInvokeStaticOrDirect::MethodLoadKind::kBssEntry;
}
code_ptr_location = HInvokeStaticOrDirect::CodePtrLocation::kCallArtMethod;
} else if (Runtime::Current()->UseJitCompilation()) {
// JIT or on-device AOT compilation referencing a boot image method.
// Use the method address directly.
method_load_kind = HInvokeStaticOrDirect::MethodLoadKind::kJitDirectAddress;
method_load_data = reinterpret_cast<uintptr_t>(callee);
code_ptr_location = HInvokeStaticOrDirect::CodePtrLocation::kCallArtMethod;
} else if (IsInBootImage(callee)) {
// Use PC-relative access to the .data.bimg.rel.ro methods array.
method_load_kind = HInvokeStaticOrDirect::MethodLoadKind::kBootImageRelRo;
code_ptr_location = HInvokeStaticOrDirect::CodePtrLocation::kCallArtMethod;
} else {
// Use PC-relative access to the .bss methods array.
method_load_kind = HInvokeStaticOrDirect::MethodLoadKind::kBssEntry;
code_ptr_location = HInvokeStaticOrDirect::CodePtrLocation::kCallArtMethod;
}
if (codegen->GetGraph()->IsDebuggable()) {
// For debuggable apps always use the code pointer from ArtMethod
// so that we don't circumvent instrumentation stubs if installed.
code_ptr_location = HInvokeStaticOrDirect::CodePtrLocation::kCallArtMethod;
}
HInvokeStaticOrDirect::DispatchInfo desired_dispatch_info = {
method_load_kind, code_ptr_location, method_load_data
};
return codegen->GetSupportedInvokeStaticOrDirectDispatch(desired_dispatch_info, callee);
}
HLoadClass::LoadKind HSharpening::ComputeLoadClassKind(
HLoadClass* load_class,
CodeGenerator* codegen,
const DexCompilationUnit& dex_compilation_unit) {
Handle<mirror::Class> klass = load_class->GetClass();
DCHECK(load_class->GetLoadKind() == HLoadClass::LoadKind::kRuntimeCall ||
load_class->GetLoadKind() == HLoadClass::LoadKind::kReferrersClass)
<< load_class->GetLoadKind();
DCHECK(!load_class->IsInBootImage()) << "HLoadClass should not be optimized before sharpening.";
HLoadClass::LoadKind load_kind = load_class->GetLoadKind();
if (load_class->NeedsAccessCheck()) {
// We need to call the runtime anyway, so we simply get the class as that call's return value.
} else if (load_kind == HLoadClass::LoadKind::kReferrersClass) {
// Loading from the ArtMethod* is the most efficient retrieval in code size.
// 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.
} else {
const DexFile& dex_file = load_class->GetDexFile();
dex::TypeIndex type_index = load_class->GetTypeIndex();
bool is_in_boot_image = false;
HLoadClass::LoadKind desired_load_kind = HLoadClass::LoadKind::kInvalid;
Runtime* runtime = Runtime::Current();
const CompilerOptions& compiler_options = codegen->GetCompilerOptions();
if (compiler_options.IsBootImage()) {
// Compiling boot image. Check if the class is a boot image class.
DCHECK(!runtime->UseJitCompilation());
if (!compiler_options.GetCompilePic()) {
// Test configuration, do not sharpen.
desired_load_kind = HLoadClass::LoadKind::kRuntimeCall;
} else if ((klass != nullptr) &&
compiler_options.IsImageClass(dex_file.StringByTypeIdx(type_index))) {
is_in_boot_image = true;
desired_load_kind = HLoadClass::LoadKind::kBootImageLinkTimePcRelative;
} else {
// Not a boot image class.
DCHECK(ContainsElement(compiler_options.GetDexFilesForOatFile(), &dex_file));
desired_load_kind = HLoadClass::LoadKind::kBssEntry;
}
} else {
is_in_boot_image = (klass != nullptr) &&
runtime->GetHeap()->ObjectIsInBootImageSpace(klass.Get());
if (runtime->UseJitCompilation()) {
DCHECK(!compiler_options.GetCompilePic());
if (is_in_boot_image) {
desired_load_kind = HLoadClass::LoadKind::kJitBootImageAddress;
} else if (klass != nullptr) {
desired_load_kind = HLoadClass::LoadKind::kJitTableAddress;
} else {
// Class not loaded yet. This happens when the dex code requesting
// this `HLoadClass` hasn't been executed in the interpreter.
// Fallback to the dex cache.
// TODO(ngeoffray): Generate HDeoptimize instead.
desired_load_kind = HLoadClass::LoadKind::kRuntimeCall;
}
} else if (is_in_boot_image) {
// AOT app compilation, boot image class.
desired_load_kind = HLoadClass::LoadKind::kBootImageRelRo;
} else {
// Not JIT and the klass is not in boot image.
desired_load_kind = HLoadClass::LoadKind::kBssEntry;
}
}
DCHECK_NE(desired_load_kind, HLoadClass::LoadKind::kInvalid);
if (is_in_boot_image) {
load_class->MarkInBootImage();
}
load_kind = codegen->GetSupportedLoadClassKind(desired_load_kind);
}
if (!IsSameDexFile(load_class->GetDexFile(), *dex_compilation_unit.GetDexFile())) {
if ((load_kind == HLoadClass::LoadKind::kRuntimeCall) ||
(load_kind == HLoadClass::LoadKind::kBssEntry)) {
// We actually cannot reference this class, we're forced to bail.
// We cannot reference this class with Bss, as the entrypoint will lookup the class
// in the caller's dex file, but that dex file does not reference the class.
return HLoadClass::LoadKind::kInvalid;
}
}
return load_kind;
}
static inline bool CanUseTypeCheckBitstring(ObjPtr<mirror::Class> klass, CodeGenerator* codegen)
REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(!klass->IsProxyClass());
DCHECK(!klass->IsArrayClass());
if (Runtime::Current()->UseJitCompilation()) {
// If we're JITting, try to assign a type check bitstring (fall through).
} else if (codegen->GetCompilerOptions().IsBootImage()) {
const char* descriptor = klass->GetDexFile().StringByTypeIdx(klass->GetDexTypeIndex());
if (!codegen->GetCompilerOptions().IsImageClass(descriptor)) {
return false;
}
// If the target is a boot image class, try to assign a type check bitstring (fall through).
// (If --force-determinism, this was already done; repeating is OK and yields the same result.)
} else {
// TODO: Use the bitstring also for AOT app compilation if the target class has a bitstring
// already assigned in the boot image.
return false;
}
// Try to assign a type check bitstring.
MutexLock subtype_check_lock(Thread::Current(), *Locks::subtype_check_lock_);
if ((false) && // FIXME: Inliner does not respect CompilerDriver::ShouldCompileMethod()
// and we're hitting an unassigned bitstring in dex2oat_image_test. b/26687569
kIsDebugBuild &&
codegen->GetCompilerOptions().IsBootImage() &&
codegen->GetCompilerOptions().IsForceDeterminism()) {
SubtypeCheckInfo::State old_state = SubtypeCheck<ObjPtr<mirror::Class>>::GetState(klass);
CHECK(old_state == SubtypeCheckInfo::kAssigned || old_state == SubtypeCheckInfo::kOverflowed)
<< klass->PrettyDescriptor() << "/" << old_state
<< " in " << codegen->GetGraph()->PrettyMethod();
}
SubtypeCheckInfo::State state = SubtypeCheck<ObjPtr<mirror::Class>>::EnsureAssigned(klass);
return state == SubtypeCheckInfo::kAssigned;
}
TypeCheckKind HSharpening::ComputeTypeCheckKind(ObjPtr<mirror::Class> klass,
CodeGenerator* codegen,
bool needs_access_check) {
if (klass == nullptr) {
return TypeCheckKind::kUnresolvedCheck;
} else if (klass->IsInterface()) {
return TypeCheckKind::kInterfaceCheck;
} else if (klass->IsArrayClass()) {
if (klass->GetComponentType()->IsObjectClass()) {
return TypeCheckKind::kArrayObjectCheck;
} else if (klass->CannotBeAssignedFromOtherTypes()) {
return TypeCheckKind::kExactCheck;
} else {
return TypeCheckKind::kArrayCheck;
}
} else if (klass->IsFinal()) { // TODO: Consider using bitstring for final classes.
return TypeCheckKind::kExactCheck;
} else if (kBitstringSubtypeCheckEnabled &&
!needs_access_check &&
CanUseTypeCheckBitstring(klass, codegen)) {
// TODO: We should not need the `!needs_access_check` check but getting rid of that
// requires rewriting some optimizations in instruction simplifier.
return TypeCheckKind::kBitstringCheck;
} else if (klass->IsAbstract()) {
return TypeCheckKind::kAbstractClassCheck;
} else {
return TypeCheckKind::kClassHierarchyCheck;
}
}
void HSharpening::ProcessLoadString(
HLoadString* load_string,
CodeGenerator* codegen,
const DexCompilationUnit& dex_compilation_unit,
VariableSizedHandleScope* handles) {
DCHECK_EQ(load_string->GetLoadKind(), HLoadString::LoadKind::kRuntimeCall);
const DexFile& dex_file = load_string->GetDexFile();
dex::StringIndex string_index = load_string->GetStringIndex();
HLoadString::LoadKind desired_load_kind = static_cast<HLoadString::LoadKind>(-1);
{
Runtime* runtime = Runtime::Current();
ClassLinker* class_linker = runtime->GetClassLinker();
ScopedObjectAccess soa(Thread::Current());
StackHandleScope<1> hs(soa.Self());
Handle<mirror::DexCache> dex_cache = IsSameDexFile(dex_file, *dex_compilation_unit.GetDexFile())
? dex_compilation_unit.GetDexCache()
: hs.NewHandle(class_linker->FindDexCache(soa.Self(), dex_file));
ObjPtr<mirror::String> string = nullptr;
const CompilerOptions& compiler_options = codegen->GetCompilerOptions();
if (compiler_options.IsBootImage()) {
// Compiling boot image. Resolve the string and allocate it if needed, to ensure
// the string will be added to the boot image.
DCHECK(!runtime->UseJitCompilation());
if (compiler_options.GetCompilePic()) {
DCHECK(ContainsElement(compiler_options.GetDexFilesForOatFile(), &dex_file));
if (compiler_options.IsForceDeterminism()) {
// Strings for methods we're compiling should be pre-resolved but Strings in inlined
// methods may not be if these inlined methods are not in the boot image profile.
// Multiple threads allocating new Strings can cause non-deterministic boot image
// because of the image relying on the order of GC roots we walk. (We could fix that
// by ordering the roots we walk in ImageWriter.) Therefore we avoid allocating these
// strings even if that results in omitting them from the boot image and using the
// sub-optimal load kind kBssEntry.
string = class_linker->LookupString(string_index, dex_cache.Get());
} else {
string = class_linker->ResolveString(string_index, dex_cache);
CHECK(string != nullptr);
}
if (string != nullptr) {
desired_load_kind = HLoadString::LoadKind::kBootImageLinkTimePcRelative;
} else {
desired_load_kind = HLoadString::LoadKind::kBssEntry;
}
} else {
// Test configuration, do not sharpen.
desired_load_kind = HLoadString::LoadKind::kRuntimeCall;
}
} else if (runtime->UseJitCompilation()) {
DCHECK(!codegen->GetCompilerOptions().GetCompilePic());
string = class_linker->LookupString(string_index, dex_cache.Get());
if (string != nullptr) {
if (runtime->GetHeap()->ObjectIsInBootImageSpace(string)) {
desired_load_kind = HLoadString::LoadKind::kJitBootImageAddress;
} else {
desired_load_kind = HLoadString::LoadKind::kJitTableAddress;
}
} else {
desired_load_kind = HLoadString::LoadKind::kRuntimeCall;
}
} else {
// AOT app compilation. Try to lookup the string without allocating if not found.
string = class_linker->LookupString(string_index, dex_cache.Get());
if (string != nullptr && runtime->GetHeap()->ObjectIsInBootImageSpace(string)) {
desired_load_kind = HLoadString::LoadKind::kBootImageRelRo;
} else {
desired_load_kind = HLoadString::LoadKind::kBssEntry;
}
}
if (string != nullptr) {
load_string->SetString(handles->NewHandle(string));
}
}
DCHECK_NE(desired_load_kind, static_cast<HLoadString::LoadKind>(-1));
HLoadString::LoadKind load_kind = codegen->GetSupportedLoadStringKind(desired_load_kind);
load_string->SetLoadKind(load_kind);
}
} // namespace art