blob: e2aca3091f83c7ffc618d094a02f4bfc6e433eb9 [file] [log] [blame]
/*
* Copyright (C) 2014 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 "inliner.h"
#include "art_method-inl.h"
#include "builder.h"
#include "class_linker.h"
#include "constant_folding.h"
#include "dead_code_elimination.h"
#include "driver/compiler_driver-inl.h"
#include "driver/compiler_options.h"
#include "driver/dex_compilation_unit.h"
#include "instruction_simplifier.h"
#include "intrinsics.h"
#include "mirror/class_loader.h"
#include "mirror/dex_cache.h"
#include "nodes.h"
#include "optimizing_compiler.h"
#include "reference_type_propagation.h"
#include "register_allocator.h"
#include "ssa_phi_elimination.h"
#include "scoped_thread_state_change.h"
#include "thread.h"
#include "dex/verified_method.h"
#include "dex/verification_results.h"
namespace art {
static constexpr size_t kMaximumNumberOfHInstructions = 12;
void HInliner::Run() {
const CompilerOptions& compiler_options = compiler_driver_->GetCompilerOptions();
if ((compiler_options.GetInlineDepthLimit() == 0)
|| (compiler_options.GetInlineMaxCodeUnits() == 0)) {
return;
}
if (graph_->IsDebuggable()) {
// For simplicity, we currently never inline when the graph is debuggable. This avoids
// doing some logic in the runtime to discover if a method could have been inlined.
return;
}
const ArenaVector<HBasicBlock*>& blocks = graph_->GetReversePostOrder();
DCHECK(!blocks.empty());
HBasicBlock* next_block = blocks[0];
for (size_t i = 0; i < blocks.size(); ++i) {
// Because we are changing the graph when inlining, we need to remember the next block.
// This avoids doing the inlining work again on the inlined blocks.
if (blocks[i] != next_block) {
continue;
}
HBasicBlock* block = next_block;
next_block = (i == blocks.size() - 1) ? nullptr : blocks[i + 1];
for (HInstruction* instruction = block->GetFirstInstruction(); instruction != nullptr;) {
HInstruction* next = instruction->GetNext();
HInvoke* call = instruction->AsInvoke();
// As long as the call is not intrinsified, it is worth trying to inline.
if (call != nullptr && call->GetIntrinsic() == Intrinsics::kNone) {
// We use the original invoke type to ensure the resolution of the called method
// works properly.
if (!TryInline(call)) {
if (kIsDebugBuild && IsCompilingWithCoreImage()) {
std::string callee_name =
PrettyMethod(call->GetDexMethodIndex(), *outer_compilation_unit_.GetDexFile());
bool should_inline = callee_name.find("$inline$") != std::string::npos;
CHECK(!should_inline) << "Could not inline " << callee_name;
}
} else {
if (kIsDebugBuild && IsCompilingWithCoreImage()) {
std::string callee_name =
PrettyMethod(call->GetDexMethodIndex(), *outer_compilation_unit_.GetDexFile());
bool must_not_inline = callee_name.find("$noinline$") != std::string::npos;
CHECK(!must_not_inline) << "Should not have inlined " << callee_name;
}
}
}
instruction = next;
}
}
}
static bool IsMethodOrDeclaringClassFinal(ArtMethod* method)
SHARED_REQUIRES(Locks::mutator_lock_) {
return method->IsFinal() || method->GetDeclaringClass()->IsFinal();
}
/**
* Given the `resolved_method` looked up in the dex cache, try to find
* the actual runtime target of an interface or virtual call.
* Return nullptr if the runtime target cannot be proven.
*/
static ArtMethod* FindVirtualOrInterfaceTarget(HInvoke* invoke, ArtMethod* resolved_method)
SHARED_REQUIRES(Locks::mutator_lock_) {
if (IsMethodOrDeclaringClassFinal(resolved_method)) {
// No need to lookup further, the resolved method will be the target.
return resolved_method;
}
HInstruction* receiver = invoke->InputAt(0);
if (receiver->IsNullCheck()) {
// Due to multiple levels of inlining within the same pass, it might be that
// null check does not have the reference type of the actual receiver.
receiver = receiver->InputAt(0);
}
ReferenceTypeInfo info = receiver->GetReferenceTypeInfo();
DCHECK(info.IsValid()) << "Invalid RTI for " << receiver->DebugName();
if (!info.IsExact()) {
// We currently only support inlining with known receivers.
// TODO: Remove this check, we should be able to inline final methods
// on unknown receivers.
return nullptr;
} else if (info.GetTypeHandle()->IsInterface()) {
// Statically knowing that the receiver has an interface type cannot
// help us find what is the target method.
return nullptr;
} else if (!resolved_method->GetDeclaringClass()->IsAssignableFrom(info.GetTypeHandle().Get())) {
// The method that we're trying to call is not in the receiver's class or super classes.
return nullptr;
}
ClassLinker* cl = Runtime::Current()->GetClassLinker();
size_t pointer_size = cl->GetImagePointerSize();
if (invoke->IsInvokeInterface()) {
resolved_method = info.GetTypeHandle()->FindVirtualMethodForInterface(
resolved_method, pointer_size);
} else {
DCHECK(invoke->IsInvokeVirtual());
resolved_method = info.GetTypeHandle()->FindVirtualMethodForVirtual(
resolved_method, pointer_size);
}
if (resolved_method == nullptr) {
// The information we had on the receiver was not enough to find
// the target method. Since we check above the exact type of the receiver,
// the only reason this can happen is an IncompatibleClassChangeError.
return nullptr;
} else if (resolved_method->IsAbstract()) {
// The information we had on the receiver was not enough to find
// the target method. Since we check above the exact type of the receiver,
// the only reason this can happen is an IncompatibleClassChangeError.
return nullptr;
} else if (IsMethodOrDeclaringClassFinal(resolved_method)) {
// A final method has to be the target method.
return resolved_method;
} else if (info.IsExact()) {
// If we found a method and the receiver's concrete type is statically
// known, we know for sure the target.
return resolved_method;
} else {
// Even if we did find a method, the receiver type was not enough to
// statically find the runtime target.
return nullptr;
}
}
static uint32_t FindMethodIndexIn(ArtMethod* method,
const DexFile& dex_file,
uint32_t referrer_index)
SHARED_REQUIRES(Locks::mutator_lock_) {
if (method->GetDexFile()->GetLocation().compare(dex_file.GetLocation()) == 0) {
return method->GetDexMethodIndex();
} else {
return method->FindDexMethodIndexInOtherDexFile(dex_file, referrer_index);
}
}
bool HInliner::TryInline(HInvoke* invoke_instruction) {
if (invoke_instruction->IsInvokeUnresolved()) {
return false; // Don't bother to move further if we know the method is unresolved.
}
uint32_t method_index = invoke_instruction->GetDexMethodIndex();
ScopedObjectAccess soa(Thread::Current());
const DexFile& caller_dex_file = *caller_compilation_unit_.GetDexFile();
VLOG(compiler) << "Try inlining " << PrettyMethod(method_index, caller_dex_file);
ClassLinker* class_linker = caller_compilation_unit_.GetClassLinker();
// We can query the dex cache directly. The verifier has populated it already.
ArtMethod* resolved_method;
if (invoke_instruction->IsInvokeStaticOrDirect()) {
MethodReference ref = invoke_instruction->AsInvokeStaticOrDirect()->GetTargetMethod();
mirror::DexCache* const dex_cache = (&caller_dex_file == ref.dex_file)
? caller_compilation_unit_.GetDexCache().Get()
: class_linker->FindDexCache(soa.Self(), *ref.dex_file);
resolved_method = dex_cache->GetResolvedMethod(
ref.dex_method_index, class_linker->GetImagePointerSize());
} else {
resolved_method = caller_compilation_unit_.GetDexCache().Get()->GetResolvedMethod(
method_index, class_linker->GetImagePointerSize());
}
if (resolved_method == nullptr) {
// TODO: Can this still happen?
// Method cannot be resolved if it is in another dex file we do not have access to.
VLOG(compiler) << "Method cannot be resolved " << PrettyMethod(method_index, caller_dex_file);
return false;
}
if (!invoke_instruction->IsInvokeStaticOrDirect()) {
resolved_method = FindVirtualOrInterfaceTarget(invoke_instruction, resolved_method);
if (resolved_method == nullptr) {
VLOG(compiler) << "Interface or virtual call to "
<< PrettyMethod(method_index, caller_dex_file)
<< " could not be statically determined";
return false;
}
// We have found a method, but we need to find where that method is for the caller's
// dex file.
method_index = FindMethodIndexIn(resolved_method, caller_dex_file, method_index);
if (method_index == DexFile::kDexNoIndex) {
VLOG(compiler) << "Interface or virtual call to "
<< PrettyMethod(resolved_method)
<< " cannot be inlined because unaccessible to caller";
return false;
}
}
bool same_dex_file =
IsSameDexFile(*outer_compilation_unit_.GetDexFile(), *resolved_method->GetDexFile());
const DexFile::CodeItem* code_item = resolved_method->GetCodeItem();
if (code_item == nullptr) {
VLOG(compiler) << "Method " << PrettyMethod(method_index, caller_dex_file)
<< " is not inlined because it is native";
return false;
}
size_t inline_max_code_units = compiler_driver_->GetCompilerOptions().GetInlineMaxCodeUnits();
if (code_item->insns_size_in_code_units_ > inline_max_code_units) {
VLOG(compiler) << "Method " << PrettyMethod(method_index, caller_dex_file)
<< " is too big to inline";
return false;
}
if (code_item->tries_size_ != 0) {
VLOG(compiler) << "Method " << PrettyMethod(method_index, caller_dex_file)
<< " is not inlined because of try block";
return false;
}
if (!resolved_method->GetDeclaringClass()->IsVerified()) {
uint16_t class_def_idx = resolved_method->GetDeclaringClass()->GetDexClassDefIndex();
if (!compiler_driver_->IsMethodVerifiedWithoutFailures(
resolved_method->GetDexMethodIndex(), class_def_idx, *resolved_method->GetDexFile())) {
VLOG(compiler) << "Method " << PrettyMethod(method_index, caller_dex_file)
<< " couldn't be verified, so it cannot be inlined";
return false;
}
}
if (invoke_instruction->IsInvokeStaticOrDirect() &&
invoke_instruction->AsInvokeStaticOrDirect()->IsStaticWithImplicitClinitCheck()) {
// Case of a static method that cannot be inlined because it implicitly
// requires an initialization check of its declaring class.
VLOG(compiler) << "Method " << PrettyMethod(method_index, caller_dex_file)
<< " is not inlined because it is static and requires a clinit"
<< " check that cannot be emitted due to Dex cache limitations";
return false;
}
if (!TryBuildAndInline(resolved_method, invoke_instruction, same_dex_file)) {
return false;
}
VLOG(compiler) << "Successfully inlined " << PrettyMethod(method_index, caller_dex_file);
MaybeRecordStat(kInlinedInvoke);
return true;
}
bool HInliner::TryBuildAndInline(ArtMethod* resolved_method,
HInvoke* invoke_instruction,
bool same_dex_file) {
ScopedObjectAccess soa(Thread::Current());
const DexFile::CodeItem* code_item = resolved_method->GetCodeItem();
const DexFile& callee_dex_file = *resolved_method->GetDexFile();
uint32_t method_index = resolved_method->GetDexMethodIndex();
ClassLinker* class_linker = caller_compilation_unit_.GetClassLinker();
Handle<mirror::DexCache> dex_cache(handles_->NewHandle(resolved_method->GetDexCache()));
DexCompilationUnit dex_compilation_unit(
nullptr,
caller_compilation_unit_.GetClassLoader(),
class_linker,
callee_dex_file,
code_item,
resolved_method->GetDeclaringClass()->GetDexClassDefIndex(),
method_index,
resolved_method->GetAccessFlags(),
compiler_driver_->GetVerifiedMethod(&callee_dex_file, method_index),
dex_cache);
bool requires_ctor_barrier = false;
if (dex_compilation_unit.IsConstructor()) {
// If it's a super invocation and we already generate a barrier there's no need
// to generate another one.
// We identify super calls by looking at the "this" pointer. If its value is the
// same as the local "this" pointer then we must have a super invocation.
bool is_super_invocation = invoke_instruction->InputAt(0)->IsParameterValue()
&& invoke_instruction->InputAt(0)->AsParameterValue()->IsThis();
if (is_super_invocation && graph_->ShouldGenerateConstructorBarrier()) {
requires_ctor_barrier = false;
} else {
Thread* self = Thread::Current();
requires_ctor_barrier = compiler_driver_->RequiresConstructorBarrier(self,
dex_compilation_unit.GetDexFile(),
dex_compilation_unit.GetClassDefIndex());
}
}
InvokeType invoke_type = invoke_instruction->GetOriginalInvokeType();
if (invoke_type == kInterface) {
// We have statically resolved the dispatch. To please the class linker
// at runtime, we change this call as if it was a virtual call.
invoke_type = kVirtual;
}
HGraph* callee_graph = new (graph_->GetArena()) HGraph(
graph_->GetArena(),
callee_dex_file,
method_index,
requires_ctor_barrier,
compiler_driver_->GetInstructionSet(),
invoke_type,
graph_->IsDebuggable(),
graph_->GetCurrentInstructionId());
OptimizingCompilerStats inline_stats;
HGraphBuilder builder(callee_graph,
&dex_compilation_unit,
&outer_compilation_unit_,
resolved_method->GetDexFile(),
compiler_driver_,
&inline_stats,
resolved_method->GetQuickenedInfo(),
dex_cache);
if (!builder.BuildGraph(*code_item)) {
VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file)
<< " could not be built, so cannot be inlined";
return false;
}
if (!RegisterAllocator::CanAllocateRegistersFor(*callee_graph,
compiler_driver_->GetInstructionSet())) {
VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file)
<< " cannot be inlined because of the register allocator";
return false;
}
if (!callee_graph->TryBuildingSsa()) {
VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file)
<< " could not be transformed to SSA";
return false;
}
size_t parameter_index = 0;
for (HInstructionIterator instructions(callee_graph->GetEntryBlock()->GetInstructions());
!instructions.Done();
instructions.Advance()) {
HInstruction* current = instructions.Current();
if (current->IsParameterValue()) {
HInstruction* argument = invoke_instruction->InputAt(parameter_index++);
if (argument->IsNullConstant()) {
current->ReplaceWith(callee_graph->GetNullConstant());
} else if (argument->IsIntConstant()) {
current->ReplaceWith(callee_graph->GetIntConstant(argument->AsIntConstant()->GetValue()));
} else if (argument->IsLongConstant()) {
current->ReplaceWith(callee_graph->GetLongConstant(argument->AsLongConstant()->GetValue()));
} else if (argument->IsFloatConstant()) {
current->ReplaceWith(
callee_graph->GetFloatConstant(argument->AsFloatConstant()->GetValue()));
} else if (argument->IsDoubleConstant()) {
current->ReplaceWith(
callee_graph->GetDoubleConstant(argument->AsDoubleConstant()->GetValue()));
} else if (argument->GetType() == Primitive::kPrimNot) {
current->SetReferenceTypeInfo(argument->GetReferenceTypeInfo());
current->AsParameterValue()->SetCanBeNull(argument->CanBeNull());
}
}
}
// Run simple optimizations on the graph.
HDeadCodeElimination dce(callee_graph, stats_);
HConstantFolding fold(callee_graph);
ReferenceTypePropagation type_propagation(callee_graph, handles_);
InstructionSimplifier simplify(callee_graph, stats_);
IntrinsicsRecognizer intrinsics(callee_graph, compiler_driver_);
HOptimization* optimizations[] = {
&intrinsics,
&type_propagation,
&simplify,
&dce,
&fold,
};
for (size_t i = 0; i < arraysize(optimizations); ++i) {
HOptimization* optimization = optimizations[i];
optimization->Run();
}
size_t number_of_instructions_budget = kMaximumNumberOfHInstructions;
if (depth_ + 1 < compiler_driver_->GetCompilerOptions().GetInlineDepthLimit()) {
HInliner inliner(callee_graph,
outer_compilation_unit_,
dex_compilation_unit,
compiler_driver_,
handles_,
stats_,
depth_ + 1);
inliner.Run();
number_of_instructions_budget += inliner.number_of_inlined_instructions_;
}
// TODO: We should abort only if all predecessors throw. However,
// HGraph::InlineInto currently does not handle an exit block with
// a throw predecessor.
HBasicBlock* exit_block = callee_graph->GetExitBlock();
if (exit_block == nullptr) {
VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file)
<< " could not be inlined because it has an infinite loop";
return false;
}
bool has_throw_predecessor = false;
for (HBasicBlock* predecessor : exit_block->GetPredecessors()) {
if (predecessor->GetLastInstruction()->IsThrow()) {
has_throw_predecessor = true;
break;
}
}
if (has_throw_predecessor) {
VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file)
<< " could not be inlined because one branch always throws";
return false;
}
HReversePostOrderIterator it(*callee_graph);
it.Advance(); // Past the entry block, it does not contain instructions that prevent inlining.
size_t number_of_instructions = 0;
for (; !it.Done(); it.Advance()) {
HBasicBlock* block = it.Current();
if (block->IsLoopHeader()) {
VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file)
<< " could not be inlined because it contains a loop";
return false;
}
for (HInstructionIterator instr_it(block->GetInstructions());
!instr_it.Done();
instr_it.Advance()) {
if (number_of_instructions++ == number_of_instructions_budget) {
VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file)
<< " could not be inlined because it is too big.";
return false;
}
HInstruction* current = instr_it.Current();
if (current->IsInvokeInterface()) {
// Disable inlining of interface calls. The cost in case of entering the
// resolution conflict is currently too high.
VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file)
<< " could not be inlined because it has an interface call.";
return false;
}
if (!same_dex_file && current->NeedsEnvironment()) {
VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file)
<< " could not be inlined because " << current->DebugName()
<< " needs an environment and is in a different dex file";
return false;
}
if (!same_dex_file && current->NeedsDexCache()) {
VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file)
<< " could not be inlined because " << current->DebugName()
<< " it is in a different dex file and requires access to the dex cache";
return false;
}
}
}
number_of_inlined_instructions_ += number_of_instructions;
HInstruction* return_replacement = callee_graph->InlineInto(graph_, invoke_instruction);
if (return_replacement != nullptr) {
DCHECK_EQ(graph_, return_replacement->GetBlock()->GetGraph());
}
// When merging the graph we might create a new NullConstant in the caller graph which does
// not have the chance to be typed. We assign the correct type here so that we can keep the
// assertion that every reference has a valid type. This also simplifies checks along the way.
HNullConstant* null_constant = graph_->GetNullConstant();
if (!null_constant->GetReferenceTypeInfo().IsValid()) {
ReferenceTypeInfo::TypeHandle obj_handle =
handles_->NewHandle(class_linker->GetClassRoot(ClassLinker::kJavaLangObject));
null_constant->SetReferenceTypeInfo(
ReferenceTypeInfo::Create(obj_handle, false /* is_exact */));
}
if ((return_replacement != nullptr)
&& (return_replacement->GetType() == Primitive::kPrimNot)) {
if (!return_replacement->GetReferenceTypeInfo().IsValid()) {
// Make sure that we have a valid type for the return. We may get an invalid one when
// we inline invokes with multiple branches and create a Phi for the result.
// TODO: we could be more precise by merging the phi inputs but that requires
// some functionality from the reference type propagation.
DCHECK(return_replacement->IsPhi());
size_t pointer_size = Runtime::Current()->GetClassLinker()->GetImagePointerSize();
ReferenceTypeInfo::TypeHandle return_handle =
handles_->NewHandle(resolved_method->GetReturnType(true /* resolve */, pointer_size));
return_replacement->SetReferenceTypeInfo(ReferenceTypeInfo::Create(
return_handle, return_handle->CannotBeAssignedFromOtherTypes() /* is_exact */));
}
}
return true;
}
} // namespace art