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LeafOS / LeafOS-Project / android_art / 1c61f7eaa824733d132e86e7bbb7617749273f1a / . / runtime / jit / jit_code_cache.cc
blob: 9d9a7d3bd41a65fe1c3eb86f49eca9e83c322456 [file] [log] [blame]
/*
* Copyright 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 "jit_code_cache.h"
#include <sstream>
#include <android-base/logging.h>
#include "arch/context.h"
#include "art_method-inl.h"
#include "base/enums.h"
#include "base/histogram-inl.h"
#include "base/logging.h" // For VLOG.
#include "base/membarrier.h"
#include "base/memfd.h"
#include "base/mem_map.h"
#include "base/quasi_atomic.h"
#include "base/stl_util.h"
#include "base/systrace.h"
#include "base/time_utils.h"
#include "base/utils.h"
#include "cha.h"
#include "debugger_interface.h"
#include "dex/dex_file_loader.h"
#include "dex/method_reference.h"
#include "entrypoints/entrypoint_utils-inl.h"
#include "entrypoints/runtime_asm_entrypoints.h"
#include "gc/accounting/bitmap-inl.h"
#include "gc/allocator/dlmalloc.h"
#include "gc/scoped_gc_critical_section.h"
#include "handle.h"
#include "handle_scope-inl.h"
#include "instrumentation.h"
#include "intern_table.h"
#include "jit/jit.h"
#include "jit/profiling_info.h"
#include "jit/jit_scoped_code_cache_write.h"
#include "linear_alloc.h"
#include "oat_file-inl.h"
#include "oat_quick_method_header.h"
#include "object_callbacks.h"
#include "profile/profile_compilation_info.h"
#include "scoped_thread_state_change-inl.h"
#include "stack.h"
#include "thread-current-inl.h"
#include "thread_list.h"
namespace art {
namespace jit {
static constexpr size_t kCodeSizeLogThreshold = 50 * KB;
static constexpr size_t kStackMapSizeLogThreshold = 50 * KB;
class JitCodeCache::JniStubKey {
public:
explicit JniStubKey(ArtMethod* method) REQUIRES_SHARED(Locks::mutator_lock_)
: shorty_(method->GetShorty()),
is_static_(method->IsStatic()),
is_fast_native_(method->IsFastNative()),
is_critical_native_(method->IsCriticalNative()),
is_synchronized_(method->IsSynchronized()) {
DCHECK(!(is_fast_native_ && is_critical_native_));
}
bool operator<(const JniStubKey& rhs) const {
if (is_static_ != rhs.is_static_) {
return rhs.is_static_;
}
if (is_synchronized_ != rhs.is_synchronized_) {
return rhs.is_synchronized_;
}
if (is_fast_native_ != rhs.is_fast_native_) {
return rhs.is_fast_native_;
}
if (is_critical_native_ != rhs.is_critical_native_) {
return rhs.is_critical_native_;
}
return strcmp(shorty_, rhs.shorty_) < 0;
}
// Update the shorty to point to another method's shorty. Call this function when removing
// the method that references the old shorty from JniCodeData and not removing the entire
// JniCodeData; the old shorty may become a dangling pointer when that method is unloaded.
void UpdateShorty(ArtMethod* method) const REQUIRES_SHARED(Locks::mutator_lock_) {
const char* shorty = method->GetShorty();
DCHECK_STREQ(shorty_, shorty);
shorty_ = shorty;
}
private:
// The shorty points to a DexFile data and may need to change
// to point to the same shorty in a different DexFile.
mutable const char* shorty_;
const bool is_static_;
const bool is_fast_native_;
const bool is_critical_native_;
const bool is_synchronized_;
};
class JitCodeCache::JniStubData {
public:
JniStubData() : code_(nullptr), methods_() {}
void SetCode(const void* code) {
DCHECK(code != nullptr);
code_ = code;
}
void UpdateEntryPoints(const void* entrypoint) REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(IsCompiled());
DCHECK(entrypoint == OatQuickMethodHeader::FromCodePointer(GetCode())->GetEntryPoint());
instrumentation::Instrumentation* instrum = Runtime::Current()->GetInstrumentation();
for (ArtMethod* m : GetMethods()) {
// Because `m` might be in the process of being deleted:
// - Call the dedicated method instead of the more generic UpdateMethodsCode
// - Check the class status without a full read barrier; use ReadBarrier::IsMarked().
bool can_set_entrypoint = true;
if (NeedsClinitCheckBeforeCall(m)) {
// To avoid resurrecting an unreachable object, we must not use a full read
// barrier but we do not want to miss updating an entrypoint under common
// circumstances, i.e. during a GC the class becomes visibly initialized,
// the method becomes hot, we compile the thunk and want to update the
// entrypoint while the method's declaring class field still points to the
// from-space class object with the old status. Therefore we read the
// declaring class without a read barrier and check if it's already marked.
// If yes, we check the status of the to-space class object as intended.
// Otherwise, there is no to-space object and the from-space class object
// contains the most recent value of the status field; even if this races
// with another thread doing a read barrier and updating the status, that's
// no different from a race with a thread that just updates the status.
// Such race can happen only for the zygote method pre-compilation, as we
// otherwise compile only thunks for methods of visibly initialized classes.
ObjPtr<mirror::Class> klass = m->GetDeclaringClass<kWithoutReadBarrier>();
ObjPtr<mirror::Class> marked = ReadBarrier::IsMarked(klass.Ptr());
ObjPtr<mirror::Class> checked_klass = (marked != nullptr) ? marked : klass;
can_set_entrypoint = checked_klass->IsVisiblyInitialized();
}
if (can_set_entrypoint) {
instrum->UpdateNativeMethodsCodeToJitCode(m, entrypoint);
}
}
}
const void* GetCode() const {
return code_;
}
bool IsCompiled() const {
return GetCode() != nullptr;
}
void AddMethod(ArtMethod* method) {
if (!ContainsElement(methods_, method)) {
methods_.push_back(method);
}
}
const std::vector<ArtMethod*>& GetMethods() const {
return methods_;
}
void RemoveMethodsIn(const LinearAlloc& alloc) REQUIRES_SHARED(Locks::mutator_lock_) {
auto kept_end = std::partition(
methods_.begin(),
methods_.end(),
[&alloc](ArtMethod* method) { return !alloc.ContainsUnsafe(method); });
for (auto it = kept_end; it != methods_.end(); it++) {
VLOG(jit) << "JIT removed (JNI) " << (*it)->PrettyMethod() << ": " << code_;
}
methods_.erase(kept_end, methods_.end());
}
bool RemoveMethod(ArtMethod* method) REQUIRES_SHARED(Locks::mutator_lock_) {
auto it = std::find(methods_.begin(), methods_.end(), method);
if (it != methods_.end()) {
VLOG(jit) << "JIT removed (JNI) " << (*it)->PrettyMethod() << ": " << code_;
methods_.erase(it);
return true;
} else {
return false;
}
}
void MoveObsoleteMethod(ArtMethod* old_method, ArtMethod* new_method) {
std::replace(methods_.begin(), methods_.end(), old_method, new_method);
}
private:
const void* code_;
std::vector<ArtMethod*> methods_;
};
JitCodeCache* JitCodeCache::Create(bool used_only_for_profile_data,
bool rwx_memory_allowed,
bool is_zygote,
std::string* error_msg) {
// Register for membarrier expedited sync core if JIT will be generating code.
if (!used_only_for_profile_data) {
if (art::membarrier(art::MembarrierCommand::kRegisterPrivateExpeditedSyncCore) != 0) {
// MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE ensures that CPU instruction pipelines are
// flushed and it's used when adding code to the JIT. The memory used by the new code may
// have just been released and, in theory, the old code could still be in a pipeline.
VLOG(jit) << "Kernel does not support membarrier sync-core";
}
}
size_t initial_capacity = Runtime::Current()->GetJITOptions()->GetCodeCacheInitialCapacity();
// Check whether the provided max capacity in options is below 1GB.
size_t max_capacity = Runtime::Current()->GetJITOptions()->GetCodeCacheMaxCapacity();
// We need to have 32 bit offsets from method headers in code cache which point to things
// in the data cache. If the maps are more than 4G apart, having multiple maps wouldn't work.
// Ensure we're below 1 GB to be safe.
if (max_capacity > 1 * GB) {
std::ostringstream oss;
oss << "Maxium code cache capacity is limited to 1 GB, "
<< PrettySize(max_capacity) << " is too big";
*error_msg = oss.str();
return nullptr;
}
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
JitMemoryRegion region;
if (!region.Initialize(initial_capacity,
max_capacity,
rwx_memory_allowed,
is_zygote,
error_msg)) {
return nullptr;
}
std::unique_ptr<JitCodeCache> jit_code_cache(new JitCodeCache());
if (is_zygote) {
// Zygote should never collect code to share the memory with the children.
jit_code_cache->garbage_collect_code_ = false;
jit_code_cache->shared_region_ = std::move(region);
} else {
jit_code_cache->private_region_ = std::move(region);
}
VLOG(jit) << "Created jit code cache: initial capacity="
<< PrettySize(initial_capacity)
<< ", maximum capacity="
<< PrettySize(max_capacity);
return jit_code_cache.release();
}
JitCodeCache::JitCodeCache()
: is_weak_access_enabled_(true),
inline_cache_cond_("Jit inline cache condition variable", *Locks::jit_lock_),
zygote_map_(&shared_region_),
lock_cond_("Jit code cache condition variable", *Locks::jit_lock_),
collection_in_progress_(false),
last_collection_increased_code_cache_(false),
garbage_collect_code_(true),
number_of_baseline_compilations_(0),
number_of_optimized_compilations_(0),
number_of_osr_compilations_(0),
number_of_collections_(0),
histogram_stack_map_memory_use_("Memory used for stack maps", 16),
histogram_code_memory_use_("Memory used for compiled code", 16),
histogram_profiling_info_memory_use_("Memory used for profiling info", 16) {
}
JitCodeCache::~JitCodeCache() {}
bool JitCodeCache::PrivateRegionContainsPc(const void* ptr) const {
return private_region_.IsInExecSpace(ptr);
}
bool JitCodeCache::ContainsPc(const void* ptr) const {
return PrivateRegionContainsPc(ptr) || shared_region_.IsInExecSpace(ptr);
}
bool JitCodeCache::ContainsMethod(ArtMethod* method) {
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
if (UNLIKELY(method->IsNative())) {
auto it = jni_stubs_map_.find(JniStubKey(method));
if (it != jni_stubs_map_.end() &&
it->second.IsCompiled() &&
ContainsElement(it->second.GetMethods(), method)) {
return true;
}
} else {
for (const auto& it : method_code_map_) {
if (it.second == method) {
return true;
}
}
if (zygote_map_.ContainsMethod(method)) {
return true;
}
}
return false;
}
const void* JitCodeCache::GetJniStubCode(ArtMethod* method) {
DCHECK(method->IsNative());
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
auto it = jni_stubs_map_.find(JniStubKey(method));
if (it != jni_stubs_map_.end()) {
JniStubData& data = it->second;
if (data.IsCompiled() && ContainsElement(data.GetMethods(), method)) {
return data.GetCode();
}
}
return nullptr;
}
const void* JitCodeCache::GetSavedEntryPointOfPreCompiledMethod(ArtMethod* method) {
if (method->IsPreCompiled()) {
const void* code_ptr = nullptr;
if (method->GetDeclaringClass()->GetClassLoader() == nullptr) {
code_ptr = zygote_map_.GetCodeFor(method);
} else {
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
auto it = saved_compiled_methods_map_.find(method);
if (it != saved_compiled_methods_map_.end()) {
code_ptr = it->second;
}
}
if (code_ptr != nullptr) {
OatQuickMethodHeader* method_header = OatQuickMethodHeader::FromCodePointer(code_ptr);
return method_header->GetEntryPoint();
}
}
return nullptr;
}
bool JitCodeCache::WaitForPotentialCollectionToComplete(Thread* self) {
bool in_collection = false;
while (collection_in_progress_) {
in_collection = true;
lock_cond_.Wait(self);
}
return in_collection;
}
static uintptr_t FromCodeToAllocation(const void* code) {
size_t alignment = GetInstructionSetAlignment(kRuntimeISA);
return reinterpret_cast<uintptr_t>(code) - RoundUp(sizeof(OatQuickMethodHeader), alignment);
}
static const void* FromAllocationToCode(const uint8_t* alloc) {
size_t alignment = GetInstructionSetAlignment(kRuntimeISA);
return reinterpret_cast<const void*>(alloc + RoundUp(sizeof(OatQuickMethodHeader), alignment));
}
static uint32_t GetNumberOfRoots(const uint8_t* stack_map) {
// The length of the table is stored just before the stack map (and therefore at the end of
// the table itself), in order to be able to fetch it from a `stack_map` pointer.
return reinterpret_cast<const uint32_t*>(stack_map)[-1];
}
static void DCheckRootsAreValid(const std::vector<Handle<mirror::Object>>& roots,
bool is_shared_region)
REQUIRES(!Locks::intern_table_lock_) REQUIRES_SHARED(Locks::mutator_lock_) {
if (!kIsDebugBuild) {
return;
}
// Put all roots in `roots_data`.
for (Handle<mirror::Object> object : roots) {
// Ensure the string is strongly interned. b/32995596
if (object->IsString()) {
ObjPtr<mirror::String> str = object->AsString();
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
CHECK(class_linker->GetInternTable()->LookupStrong(Thread::Current(), str) != nullptr);
}
// Ensure that we don't put movable objects in the shared region.
if (is_shared_region) {
CHECK(!Runtime::Current()->GetHeap()->IsMovableObject(object.Get()));
}
}
}
static const uint8_t* GetRootTable(const void* code_ptr, uint32_t* number_of_roots = nullptr) {
OatQuickMethodHeader* method_header = OatQuickMethodHeader::FromCodePointer(code_ptr);
uint8_t* data = method_header->GetOptimizedCodeInfoPtr();
uint32_t roots = GetNumberOfRoots(data);
if (number_of_roots != nullptr) {
*number_of_roots = roots;
}
return data - ComputeRootTableSize(roots);
}
void JitCodeCache::SweepRootTables(IsMarkedVisitor* visitor) {
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
for (const auto& entry : method_code_map_) {
uint32_t number_of_roots = 0;
const uint8_t* root_table = GetRootTable(entry.first, &number_of_roots);
uint8_t* roots_data = private_region_.IsInDataSpace(root_table)
? private_region_.GetWritableDataAddress(root_table)
: shared_region_.GetWritableDataAddress(root_table);
GcRoot<mirror::Object>* roots = reinterpret_cast<GcRoot<mirror::Object>*>(roots_data);
for (uint32_t i = 0; i < number_of_roots; ++i) {
// This does not need a read barrier because this is called by GC.
mirror::Object* object = roots[i].Read<kWithoutReadBarrier>();
if (object == nullptr || object == Runtime::GetWeakClassSentinel()) {
// entry got deleted in a previous sweep.
} else if (object->IsString<kDefaultVerifyFlags>()) {
mirror::Object* new_object = visitor->IsMarked(object);
// We know the string is marked because it's a strongly-interned string that
// is always alive. The IsMarked implementation of the CMS collector returns
// null for newly allocated objects, but we know those haven't moved. Therefore,
// only update the entry if we get a different non-null string.
// TODO: Do not use IsMarked for j.l.Class, and adjust once we move this method
// out of the weak access/creation pause. b/32167580
if (new_object != nullptr && new_object != object) {
DCHECK(new_object->IsString());
roots[i] = GcRoot<mirror::Object>(new_object);
}
} else {
Runtime::ProcessWeakClass(
reinterpret_cast<GcRoot<mirror::Class>*>(&roots[i]),
visitor,
Runtime::GetWeakClassSentinel());
}
}
}
// Walk over inline caches to clear entries containing unloaded classes.
for (auto it : profiling_infos_) {
ProfilingInfo* info = it.second;
for (size_t i = 0; i < info->number_of_inline_caches_; ++i) {
InlineCache* cache = &info->cache_[i];
for (size_t j = 0; j < InlineCache::kIndividualCacheSize; ++j) {
Runtime::ProcessWeakClass(&cache->classes_[j], visitor, nullptr);
}
}
}
}
void JitCodeCache::FreeCodeAndData(const void* code_ptr) {
if (IsInZygoteExecSpace(code_ptr)) {
// No need to free, this is shared memory.
return;
}
uintptr_t allocation = FromCodeToAllocation(code_ptr);
const uint8_t* data = nullptr;
if (OatQuickMethodHeader::FromCodePointer(code_ptr)->IsOptimized()) {
data = GetRootTable(code_ptr);
} // else this is a JNI stub without any data.
FreeLocked(&private_region_, reinterpret_cast<uint8_t*>(allocation), data);
}
void JitCodeCache::FreeAllMethodHeaders(
const std::unordered_set<OatQuickMethodHeader*>& method_headers) {
// We need to remove entries in method_headers from CHA dependencies
// first since once we do FreeCode() below, the memory can be reused
// so it's possible for the same method_header to start representing
// different compile code.
{
MutexLock mu2(Thread::Current(), *Locks::cha_lock_);
Runtime::Current()->GetClassLinker()->GetClassHierarchyAnalysis()
->RemoveDependentsWithMethodHeaders(method_headers);
}
ScopedCodeCacheWrite scc(private_region_);
for (const OatQuickMethodHeader* method_header : method_headers) {
FreeCodeAndData(method_header->GetCode());
}
// We have potentially removed a lot of debug info. Do maintenance pass to save space.
RepackNativeDebugInfoForJit();
// Check that the set of compiled methods exactly matches native debug information.
// Does not check zygote methods since they can change concurrently.
if (kIsDebugBuild && !Runtime::Current()->IsZygote()) {
std::map<const void*, ArtMethod*> compiled_methods;
VisitAllMethods([&](const void* addr, ArtMethod* method) {
if (!IsInZygoteExecSpace(addr)) {
CHECK(addr != nullptr && method != nullptr);
compiled_methods.emplace(addr, method);
}
});
std::set<const void*> debug_info;
ForEachNativeDebugSymbol([&](const void* addr, size_t, const char* name) {
addr = AlignDown(addr, GetInstructionSetInstructionAlignment(kRuntimeISA)); // Thumb-bit.
CHECK(debug_info.emplace(addr).second) << "Duplicate debug info: " << addr << " " << name;
CHECK_EQ(compiled_methods.count(addr), 1u) << "Extra debug info: " << addr << " " << name;
});
if (!debug_info.empty()) { // If debug-info generation is enabled.
for (auto it : compiled_methods) {
CHECK_EQ(debug_info.count(it.first), 1u) << "No debug info: " << it.second->PrettyMethod();
}
CHECK_EQ(compiled_methods.size(), debug_info.size());
}
}
}
void JitCodeCache::RemoveMethodsIn(Thread* self, const LinearAlloc& alloc) {
ScopedTrace trace(__PRETTY_FUNCTION__);
// We use a set to first collect all method_headers whose code need to be
// removed. We need to free the underlying code after we remove CHA dependencies
// for entries in this set. And it's more efficient to iterate through
// the CHA dependency map just once with an unordered_set.
std::unordered_set<OatQuickMethodHeader*> method_headers;
{
MutexLock mu(self, *Locks::jit_lock_);
// We do not check if a code cache GC is in progress, as this method comes
// with the classlinker_classes_lock_ held, and suspending ourselves could
// lead to a deadlock.
{
for (auto it = jni_stubs_map_.begin(); it != jni_stubs_map_.end();) {
it->second.RemoveMethodsIn(alloc);
if (it->second.GetMethods().empty()) {
method_headers.insert(OatQuickMethodHeader::FromCodePointer(it->second.GetCode()));
it = jni_stubs_map_.erase(it);
} else {
it->first.UpdateShorty(it->second.GetMethods().front());
++it;
}
}
for (auto it = method_code_map_.begin(); it != method_code_map_.end();) {
if (alloc.ContainsUnsafe(it->second)) {
method_headers.insert(OatQuickMethodHeader::FromCodePointer(it->first));
VLOG(jit) << "JIT removed " << it->second->PrettyMethod() << ": " << it->first;
it = method_code_map_.erase(it);
} else {
++it;
}
}
}
for (auto it = osr_code_map_.begin(); it != osr_code_map_.end();) {
if (alloc.ContainsUnsafe(it->first)) {
// Note that the code has already been pushed to method_headers in the loop
// above and is going to be removed in FreeCode() below.
it = osr_code_map_.erase(it);
} else {
++it;
}
}
for (auto it = profiling_infos_.begin(); it != profiling_infos_.end();) {
ProfilingInfo* info = it->second;
if (alloc.ContainsUnsafe(info->GetMethod())) {
private_region_.FreeWritableData(reinterpret_cast<uint8_t*>(info));
it = profiling_infos_.erase(it);
} else {
++it;
}
}
FreeAllMethodHeaders(method_headers);
}
}
bool JitCodeCache::IsWeakAccessEnabled(Thread* self) const {
return kUseReadBarrier
? self->GetWeakRefAccessEnabled()
: is_weak_access_enabled_.load(std::memory_order_seq_cst);
}
void JitCodeCache::WaitUntilInlineCacheAccessible(Thread* self) {
if (IsWeakAccessEnabled(self)) {
return;
}
ScopedThreadSuspension sts(self, kWaitingWeakGcRootRead);
MutexLock mu(self, *Locks::jit_lock_);
while (!IsWeakAccessEnabled(self)) {
inline_cache_cond_.Wait(self);
}
}
void JitCodeCache::BroadcastForInlineCacheAccess() {
Thread* self = Thread::Current();
MutexLock mu(self, *Locks::jit_lock_);
inline_cache_cond_.Broadcast(self);
}
void JitCodeCache::AllowInlineCacheAccess() {
DCHECK(!kUseReadBarrier);
is_weak_access_enabled_.store(true, std::memory_order_seq_cst);
BroadcastForInlineCacheAccess();
}
void JitCodeCache::DisallowInlineCacheAccess() {
DCHECK(!kUseReadBarrier);
is_weak_access_enabled_.store(false, std::memory_order_seq_cst);
}
void JitCodeCache::CopyInlineCacheInto(
const InlineCache& ic,
/*out*/StackHandleScope<InlineCache::kIndividualCacheSize>* classes) {
static_assert(arraysize(ic.classes_) == InlineCache::kIndividualCacheSize);
DCHECK_EQ(classes->NumberOfReferences(), InlineCache::kIndividualCacheSize);
DCHECK_EQ(classes->RemainingSlots(), InlineCache::kIndividualCacheSize);
WaitUntilInlineCacheAccessible(Thread::Current());
// Note that we don't need to lock `lock_` here, the compiler calling
// this method has already ensured the inline cache will not be deleted.
for (const GcRoot<mirror::Class>& root : ic.classes_) {
mirror::Class* object = root.Read();
if (object != nullptr) {
DCHECK_NE(classes->RemainingSlots(), 0u);
classes->NewHandle(object);
}
}
}
static void ClearMethodCounter(ArtMethod* method, bool was_warm)
REQUIRES_SHARED(Locks::mutator_lock_) {
if (was_warm) {
method->SetPreviouslyWarm();
}
// We reset the counter to 1 so that the profile knows that the method was executed at least once.
// This is required for layout purposes.
// We also need to make sure we'll pass the warmup threshold again, so we set to 0 if
// the warmup threshold is 1.
uint16_t jit_warmup_threshold = Runtime::Current()->GetJITOptions()->GetWarmupThreshold();
method->SetCounter(std::min(jit_warmup_threshold - 1, 1));
}
void JitCodeCache::WaitForPotentialCollectionToCompleteRunnable(Thread* self) {
while (collection_in_progress_) {
Locks::jit_lock_->Unlock(self);
{
ScopedThreadSuspension sts(self, kSuspended);
MutexLock mu(self, *Locks::jit_lock_);
WaitForPotentialCollectionToComplete(self);
}
Locks::jit_lock_->Lock(self);
}
}
bool JitCodeCache::Commit(Thread* self,
JitMemoryRegion* region,
ArtMethod* method,
ArrayRef<const uint8_t> reserved_code,
ArrayRef<const uint8_t> code,
ArrayRef<const uint8_t> reserved_data,
const std::vector<Handle<mirror::Object>>& roots,
ArrayRef<const uint8_t> stack_map,
const std::vector<uint8_t>& debug_info,
bool is_full_debug_info,
CompilationKind compilation_kind,
bool has_should_deoptimize_flag,
const ArenaSet<ArtMethod*>& cha_single_implementation_list) {
DCHECK(!method->IsNative() || (compilation_kind != CompilationKind::kOsr));
if (!method->IsNative()) {
// We need to do this before grabbing the lock_ because it needs to be able to see the string
// InternTable. Native methods do not have roots.
DCheckRootsAreValid(roots, IsSharedRegion(*region));
}
const uint8_t* roots_data = reserved_data.data();
size_t root_table_size = ComputeRootTableSize(roots.size());
const uint8_t* stack_map_data = roots_data + root_table_size;
MutexLock mu(self, *Locks::jit_lock_);
// We need to make sure that there will be no jit-gcs going on and wait for any ongoing one to
// finish.
WaitForPotentialCollectionToCompleteRunnable(self);
const uint8_t* code_ptr = region->CommitCode(
reserved_code, code, stack_map_data, has_should_deoptimize_flag);
if (code_ptr == nullptr) {
return false;
}
OatQuickMethodHeader* method_header = OatQuickMethodHeader::FromCodePointer(code_ptr);
// Commit roots and stack maps before updating the entry point.
if (!region->CommitData(reserved_data, roots, stack_map)) {
return false;
}
switch (compilation_kind) {
case CompilationKind::kOsr:
number_of_osr_compilations_++;
break;
case CompilationKind::kBaseline:
number_of_baseline_compilations_++;
break;
case CompilationKind::kOptimized:
number_of_optimized_compilations_++;
break;
}
// We need to update the debug info before the entry point gets set.
// At the same time we want to do under JIT lock so that debug info and JIT maps are in sync.
if (!debug_info.empty()) {
// NB: Don't allow packing of full info since it would remove non-backtrace data.
AddNativeDebugInfoForJit(code_ptr, debug_info, /*allow_packing=*/ !is_full_debug_info);
}
// We need to update the entry point in the runnable state for the instrumentation.
{
// The following needs to be guarded by cha_lock_ also. Otherwise it's possible that the
// compiled code is considered invalidated by some class linking, but below we still make the
// compiled code valid for the method. Need cha_lock_ for checking all single-implementation
// flags and register dependencies.
MutexLock cha_mu(self, *Locks::cha_lock_);
bool single_impl_still_valid = true;
for (ArtMethod* single_impl : cha_single_implementation_list) {
if (!single_impl->HasSingleImplementation()) {
// Simply discard the compiled code. Clear the counter so that it may be recompiled later.
// Hopefully the class hierarchy will be more stable when compilation is retried.
single_impl_still_valid = false;
ClearMethodCounter(method, /*was_warm=*/ false);
break;
}
}
// Discard the code if any single-implementation assumptions are now invalid.
if (UNLIKELY(!single_impl_still_valid)) {
VLOG(jit) << "JIT discarded jitted code due to invalid single-implementation assumptions.";
return false;
}
DCHECK(cha_single_implementation_list.empty() || !Runtime::Current()->IsJavaDebuggable())
<< "Should not be using cha on debuggable apps/runs!";
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
for (ArtMethod* single_impl : cha_single_implementation_list) {
class_linker->GetClassHierarchyAnalysis()->AddDependency(single_impl, method, method_header);
}
if (UNLIKELY(method->IsNative())) {
auto it = jni_stubs_map_.find(JniStubKey(method));
DCHECK(it != jni_stubs_map_.end())
<< "Entry inserted in NotifyCompilationOf() should be alive.";
JniStubData* data = &it->second;
DCHECK(ContainsElement(data->GetMethods(), method))
<< "Entry inserted in NotifyCompilationOf() should contain this method.";
data->SetCode(code_ptr);
data->UpdateEntryPoints(method_header->GetEntryPoint());
} else {
if (method->IsPreCompiled() && IsSharedRegion(*region)) {
zygote_map_.Put(code_ptr, method);
} else {
method_code_map_.Put(code_ptr, method);
}
if (compilation_kind == CompilationKind::kOsr) {
osr_code_map_.Put(method, code_ptr);
} else if (NeedsClinitCheckBeforeCall(method) &&
!method->GetDeclaringClass()->IsVisiblyInitialized()) {
// This situation currently only occurs in the jit-zygote mode.
DCHECK(!garbage_collect_code_);
DCHECK(method->IsPreCompiled());
// The shared region can easily be queried. For the private region, we
// use a side map.
if (!IsSharedRegion(*region)) {
saved_compiled_methods_map_.Put(method, code_ptr);
}
} else {
Runtime::Current()->GetInstrumentation()->UpdateMethodsCode(
method, method_header->GetEntryPoint());
}
}
if (collection_in_progress_) {
// We need to update the live bitmap if there is a GC to ensure it sees this new
// code.
GetLiveBitmap()->AtomicTestAndSet(FromCodeToAllocation(code_ptr));
}
VLOG(jit)
<< "JIT added (kind=" << compilation_kind << ") "
<< ArtMethod::PrettyMethod(method) << "@" << method
<< " ccache_size=" << PrettySize(CodeCacheSizeLocked()) << ": "
<< " dcache_size=" << PrettySize(DataCacheSizeLocked()) << ": "
<< reinterpret_cast<const void*>(method_header->GetEntryPoint()) << ","
<< reinterpret_cast<const void*>(method_header->GetEntryPoint() +
method_header->GetCodeSize());
}
return true;
}
size_t JitCodeCache::CodeCacheSize() {
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
return CodeCacheSizeLocked();
}
bool JitCodeCache::RemoveMethod(ArtMethod* method, bool release_memory) {
// This function is used only for testing and only with non-native methods.
CHECK(!method->IsNative());
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
bool osr = osr_code_map_.find(method) != osr_code_map_.end();
bool in_cache = RemoveMethodLocked(method, release_memory);
if (!in_cache) {
return false;
}
method->SetCounter(0);
Runtime::Current()->GetInstrumentation()->UpdateMethodsCode(
method, GetQuickToInterpreterBridge());
VLOG(jit)
<< "JIT removed (osr=" << std::boolalpha << osr << std::noboolalpha << ") "
<< ArtMethod::PrettyMethod(method) << "@" << method
<< " ccache_size=" << PrettySize(CodeCacheSizeLocked()) << ": "
<< " dcache_size=" << PrettySize(DataCacheSizeLocked());
return true;
}
bool JitCodeCache::RemoveMethodLocked(ArtMethod* method, bool release_memory) {
if (LIKELY(!method->IsNative())) {
auto it = profiling_infos_.find(method);
if (it != profiling_infos_.end()) {
profiling_infos_.erase(it);
}
}
bool in_cache = false;
ScopedCodeCacheWrite ccw(private_region_);
if (UNLIKELY(method->IsNative())) {
auto it = jni_stubs_map_.find(JniStubKey(method));
if (it != jni_stubs_map_.end() && it->second.RemoveMethod(method)) {
in_cache = true;
if (it->second.GetMethods().empty()) {
if (release_memory) {
FreeCodeAndData(it->second.GetCode());
}
jni_stubs_map_.erase(it);
} else {
it->first.UpdateShorty(it->second.GetMethods().front());
}
}
} else {
for (auto it = method_code_map_.begin(); it != method_code_map_.end();) {
if (it->second == method) {
in_cache = true;
if (release_memory) {
FreeCodeAndData(it->first);
}
VLOG(jit) << "JIT removed " << it->second->PrettyMethod() << ": " << it->first;
it = method_code_map_.erase(it);
} else {
++it;
}
}
auto osr_it = osr_code_map_.find(method);
if (osr_it != osr_code_map_.end()) {
osr_code_map_.erase(osr_it);
}
}
return in_cache;
}
// This notifies the code cache that the given method has been redefined and that it should remove
// any cached information it has on the method. All threads must be suspended before calling this
// method. The compiled code for the method (if there is any) must not be in any threads call stack.
void JitCodeCache::NotifyMethodRedefined(ArtMethod* method) {
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
RemoveMethodLocked(method, /* release_memory= */ true);
}
// This invalidates old_method. Once this function returns one can no longer use old_method to
// execute code unless it is fixed up. This fixup will happen later in the process of installing a
// class redefinition.
// TODO We should add some info to ArtMethod to note that 'old_method' has been invalidated and
// shouldn't be used since it is no longer logically in the jit code cache.
// TODO We should add DCHECKS that validate that the JIT is paused when this method is entered.
void JitCodeCache::MoveObsoleteMethod(ArtMethod* old_method, ArtMethod* new_method) {
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
if (old_method->IsNative()) {
// Update methods in jni_stubs_map_.
for (auto& entry : jni_stubs_map_) {
JniStubData& data = entry.second;
data.MoveObsoleteMethod(old_method, new_method);
}
return;
}
// Update method_code_map_ to point to the new method.
for (auto& it : method_code_map_) {
if (it.second == old_method) {
it.second = new_method;
}
}
// Update osr_code_map_ to point to the new method.
auto code_map = osr_code_map_.find(old_method);
if (code_map != osr_code_map_.end()) {
osr_code_map_.Put(new_method, code_map->second);
osr_code_map_.erase(old_method);
}
}
void JitCodeCache::TransitionToDebuggable() {
// Check that none of our methods have an entrypoint in the zygote exec
// space (this should be taken care of by
// ClassLinker::UpdateEntryPointsClassVisitor.
{
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
if (kIsDebugBuild) {
for (const auto& it : method_code_map_) {
ArtMethod* method = it.second;
DCHECK(!method->IsPreCompiled());
DCHECK(!IsInZygoteExecSpace(method->GetEntryPointFromQuickCompiledCode()));
}
}
// Not strictly necessary, but this map is useless now.
saved_compiled_methods_map_.clear();
}
if (kIsDebugBuild) {
for (const auto& entry : zygote_map_) {
ArtMethod* method = entry.method;
if (method != nullptr) {
DCHECK(!method->IsPreCompiled());
DCHECK(!IsInZygoteExecSpace(method->GetEntryPointFromQuickCompiledCode()));
}
}
}
}
size_t JitCodeCache::CodeCacheSizeLocked() {
return GetCurrentRegion()->GetUsedMemoryForCode();
}
size_t JitCodeCache::DataCacheSize() {
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
return DataCacheSizeLocked();
}
size_t JitCodeCache::DataCacheSizeLocked() {
return GetCurrentRegion()->GetUsedMemoryForData();
}
bool JitCodeCache::Reserve(Thread* self,
JitMemoryRegion* region,
size_t code_size,
size_t stack_map_size,
size_t number_of_roots,
ArtMethod* method,
/*out*/ArrayRef<const uint8_t>* reserved_code,
/*out*/ArrayRef<const uint8_t>* reserved_data) {
code_size = OatQuickMethodHeader::InstructionAlignedSize() + code_size;
size_t data_size = RoundUp(ComputeRootTableSize(number_of_roots) + stack_map_size, sizeof(void*));
const uint8_t* code;
const uint8_t* data;
while (true) {
bool at_max_capacity = false;
{
ScopedThreadSuspension sts(self, kSuspended);
MutexLock mu(self, *Locks::jit_lock_);
WaitForPotentialCollectionToComplete(self);
ScopedCodeCacheWrite ccw(*region);
code = region->AllocateCode(code_size);
data = region->AllocateData(data_size);
at_max_capacity = IsAtMaxCapacity();
}
if (code != nullptr && data != nullptr) {
break;
}
Free(self, region, code, data);
if (at_max_capacity) {
VLOG(jit) << "JIT failed to allocate code of size "
<< PrettySize(code_size)
<< ", and data of size "
<< PrettySize(data_size);
return false;
}
// Run a code cache collection and try again.
GarbageCollectCache(self);
}
*reserved_code = ArrayRef<const uint8_t>(code, code_size);
*reserved_data = ArrayRef<const uint8_t>(data, data_size);
MutexLock mu(self, *Locks::jit_lock_);
histogram_code_memory_use_.AddValue(code_size);
if (code_size > kCodeSizeLogThreshold) {
LOG(INFO) << "JIT allocated "
<< PrettySize(code_size)
<< " for compiled code of "
<< ArtMethod::PrettyMethod(method);
}
histogram_stack_map_memory_use_.AddValue(data_size);
if (data_size > kStackMapSizeLogThreshold) {
LOG(INFO) << "JIT allocated "
<< PrettySize(data_size)
<< " for stack maps of "
<< ArtMethod::PrettyMethod(method);
}
return true;
}
void JitCodeCache::Free(Thread* self,
JitMemoryRegion* region,
const uint8_t* code,
const uint8_t* data) {
MutexLock mu(self, *Locks::jit_lock_);
ScopedCodeCacheWrite ccw(*region);
FreeLocked(region, code, data);
}
void JitCodeCache::FreeLocked(JitMemoryRegion* region, const uint8_t* code, const uint8_t* data) {
if (code != nullptr) {
RemoveNativeDebugInfoForJit(reinterpret_cast<const void*>(FromAllocationToCode(code)));
region->FreeCode(code);
}
if (data != nullptr) {
region->FreeData(data);
}
}
class MarkCodeClosure final : public Closure {
public:
MarkCodeClosure(JitCodeCache* code_cache, CodeCacheBitmap* bitmap, Barrier* barrier)
: code_cache_(code_cache), bitmap_(bitmap), barrier_(barrier) {}
void Run(Thread* thread) override REQUIRES_SHARED(Locks::mutator_lock_) {
ScopedTrace trace(__PRETTY_FUNCTION__);
DCHECK(thread == Thread::Current() || thread->IsSuspended());
StackVisitor::WalkStack(
[&](const art::StackVisitor* stack_visitor) {
const OatQuickMethodHeader* method_header =
stack_visitor->GetCurrentOatQuickMethodHeader();
if (method_header == nullptr) {
return true;
}
const void* code = method_header->GetCode();
if (code_cache_->ContainsPc(code) && !code_cache_->IsInZygoteExecSpace(code)) {
// Use the atomic set version, as multiple threads are executing this code.
bitmap_->AtomicTestAndSet(FromCodeToAllocation(code));
}
return true;
},
thread,
/* context= */ nullptr,
art::StackVisitor::StackWalkKind::kSkipInlinedFrames);
if (kIsDebugBuild) {
// The stack walking code queries the side instrumentation stack if it
// sees an instrumentation exit pc, so the JIT code of methods in that stack
// must have been seen. We check this below.
for (const auto& it : *thread->GetInstrumentationStack()) {
// The 'method_' in InstrumentationStackFrame is the one that has return_pc_ in
// its stack frame, it is not the method owning return_pc_. We just pass null to
// LookupMethodHeader: the method is only checked against in debug builds.
OatQuickMethodHeader* method_header =
code_cache_->LookupMethodHeader(it.second.return_pc_, /* method= */ nullptr);
if (method_header != nullptr) {
const void* code = method_header->GetCode();
CHECK(bitmap_->Test(FromCodeToAllocation(code)));
}
}
}
barrier_->Pass(Thread::Current());
}
private:
JitCodeCache* const code_cache_;
CodeCacheBitmap* const bitmap_;
Barrier* const barrier_;
};
void JitCodeCache::NotifyCollectionDone(Thread* self) {
collection_in_progress_ = false;
lock_cond_.Broadcast(self);
}
void JitCodeCache::MarkCompiledCodeOnThreadStacks(Thread* self) {
Barrier barrier(0);
size_t threads_running_checkpoint = 0;
MarkCodeClosure closure(this, GetLiveBitmap(), &barrier);
threads_running_checkpoint = Runtime::Current()->GetThreadList()->RunCheckpoint(&closure);
// Now that we have run our checkpoint, move to a suspended state and wait
// for other threads to run the checkpoint.
ScopedThreadSuspension sts(self, kSuspended);
if (threads_running_checkpoint != 0) {
barrier.Increment(self, threads_running_checkpoint);
}
}
bool JitCodeCache::IsAtMaxCapacity() const {
return private_region_.GetCurrentCapacity() == private_region_.GetMaxCapacity();
}
bool JitCodeCache::ShouldDoFullCollection() {
if (IsAtMaxCapacity()) {
// Always do a full collection when the code cache is full.
return true;
} else if (private_region_.GetCurrentCapacity() < kReservedCapacity) {
// Always do partial collection when the code cache size is below the reserved
// capacity.
return false;
} else if (last_collection_increased_code_cache_) {
// This time do a full collection.
return true;
} else {
// This time do a partial collection.
return false;
}
}
void JitCodeCache::GarbageCollectCache(Thread* self) {
ScopedTrace trace(__FUNCTION__);
// Wait for an existing collection, or let everyone know we are starting one.
{
ScopedThreadSuspension sts(self, kSuspended);
MutexLock mu(self, *Locks::jit_lock_);
if (!garbage_collect_code_) {
private_region_.IncreaseCodeCacheCapacity();
return;
} else if (WaitForPotentialCollectionToComplete(self)) {
return;
} else {
number_of_collections_++;
live_bitmap_.reset(CodeCacheBitmap::Create(
"code-cache-bitmap",
reinterpret_cast<uintptr_t>(private_region_.GetExecPages()->Begin()),
reinterpret_cast<uintptr_t>(
private_region_.GetExecPages()->Begin() + private_region_.GetCurrentCapacity() / 2)));
collection_in_progress_ = true;
}
}
TimingLogger logger("JIT code cache timing logger", true, VLOG_IS_ON(jit));
{
TimingLogger::ScopedTiming st("Code cache collection", &logger);
bool do_full_collection = false;
{
MutexLock mu(self, *Locks::jit_lock_);
do_full_collection = ShouldDoFullCollection();
}
VLOG(jit) << "Do "
<< (do_full_collection ? "full" : "partial")
<< " code cache collection, code="
<< PrettySize(CodeCacheSize())
<< ", data=" << PrettySize(DataCacheSize());
DoCollection(self, /* collect_profiling_info= */ do_full_collection);
VLOG(jit) << "After code cache collection, code="
<< PrettySize(CodeCacheSize())
<< ", data=" << PrettySize(DataCacheSize());
{
MutexLock mu(self, *Locks::jit_lock_);
// Increase the code cache only when we do partial collections.
// TODO: base this strategy on how full the code cache is?
if (do_full_collection) {
last_collection_increased_code_cache_ = false;
} else {
last_collection_increased_code_cache_ = true;
private_region_.IncreaseCodeCacheCapacity();
}
bool next_collection_will_be_full = ShouldDoFullCollection();
// Start polling the liveness of compiled code to prepare for the next full collection.
if (next_collection_will_be_full) {
for (auto it : profiling_infos_) {
it.second->SetBaselineHotnessCount(0);
}
// Change entry points of native methods back to the GenericJNI entrypoint.
for (const auto& entry : jni_stubs_map_) {
const JniStubData& data = entry.second;
if (!data.IsCompiled() || IsInZygoteExecSpace(data.GetCode())) {
continue;
}
// Make sure a single invocation of the GenericJNI trampoline tries to recompile.
uint16_t new_counter = Runtime::Current()->GetJit()->HotMethodThreshold() - 1u;
const OatQuickMethodHeader* method_header =
OatQuickMethodHeader::FromCodePointer(data.GetCode());
for (ArtMethod* method : data.GetMethods()) {
if (method->GetEntryPointFromQuickCompiledCode() == method_header->GetEntryPoint()) {
// Don't call Instrumentation::UpdateMethodsCode(), same as for normal methods above.
method->SetCounter(new_counter);
method->SetEntryPointFromQuickCompiledCode(GetQuickGenericJniStub());
}
}
}
}
live_bitmap_.reset(nullptr);
NotifyCollectionDone(self);
}
}
Runtime::Current()->GetJit()->AddTimingLogger(logger);
}
void JitCodeCache::RemoveUnmarkedCode(Thread* self) {
ScopedTrace trace(__FUNCTION__);
std::unordered_set<OatQuickMethodHeader*> method_headers;
{
MutexLock mu(self, *Locks::jit_lock_);
// Iterate over all compiled code and remove entries that are not marked.
for (auto it = jni_stubs_map_.begin(); it != jni_stubs_map_.end();) {
JniStubData* data = &it->second;
if (IsInZygoteExecSpace(data->GetCode()) ||
!data->IsCompiled() ||
GetLiveBitmap()->Test(FromCodeToAllocation(data->GetCode()))) {
++it;
} else {
method_headers.insert(OatQuickMethodHeader::FromCodePointer(data->GetCode()));
for (ArtMethod* method : data->GetMethods()) {
VLOG(jit) << "JIT removed (JNI) " << method->PrettyMethod() << ": " << data->GetCode();
}
it = jni_stubs_map_.erase(it);
}
}
for (auto it = method_code_map_.begin(); it != method_code_map_.end();) {
const void* code_ptr = it->first;
uintptr_t allocation = FromCodeToAllocation(code_ptr);
if (IsInZygoteExecSpace(code_ptr) || GetLiveBitmap()->Test(allocation)) {
++it;
} else {
OatQuickMethodHeader* header = OatQuickMethodHeader::FromCodePointer(code_ptr);
method_headers.insert(header);
VLOG(jit) << "JIT removed " << it->second->PrettyMethod() << ": " << it->first;
it = method_code_map_.erase(it);
}
}
FreeAllMethodHeaders(method_headers);
}
}
bool JitCodeCache::GetGarbageCollectCode() {
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
return garbage_collect_code_;
}
void JitCodeCache::SetGarbageCollectCode(bool value) {
Thread* self = Thread::Current();
MutexLock mu(self, *Locks::jit_lock_);
// Update the flag while holding the lock to ensure no thread will try to GC.
garbage_collect_code_ = value;
}
void JitCodeCache::RemoveMethodBeingCompiled(ArtMethod* method, CompilationKind kind) {
DCHECK(IsMethodBeingCompiled(method, kind));
switch (kind) {
case CompilationKind::kOsr:
current_osr_compilations_.erase(method);
break;
case CompilationKind::kBaseline:
current_baseline_compilations_.erase(method);
break;
case CompilationKind::kOptimized:
current_optimized_compilations_.erase(method);
break;
}
}
void JitCodeCache::AddMethodBeingCompiled(ArtMethod* method, CompilationKind kind) {
DCHECK(!IsMethodBeingCompiled(method, kind));
switch (kind) {
case CompilationKind::kOsr:
current_osr_compilations_.insert(method);
break;
case CompilationKind::kBaseline:
current_baseline_compilations_.insert(method);
break;
case CompilationKind::kOptimized:
current_optimized_compilations_.insert(method);
break;
}
}
bool JitCodeCache::IsMethodBeingCompiled(ArtMethod* method, CompilationKind kind) {
switch (kind) {
case CompilationKind::kOsr:
return ContainsElement(current_osr_compilations_, method);
case CompilationKind::kBaseline:
return ContainsElement(current_baseline_compilations_, method);
case CompilationKind::kOptimized:
return ContainsElement(current_optimized_compilations_, method);
}
}
bool JitCodeCache::IsMethodBeingCompiled(ArtMethod* method) {
return ContainsElement(current_optimized_compilations_, method) ||
ContainsElement(current_osr_compilations_, method) ||
ContainsElement(current_baseline_compilations_, method);
}
void JitCodeCache::DoCollection(Thread* self, bool collect_profiling_info) {
ScopedTrace trace(__FUNCTION__);
{
MutexLock mu(self, *Locks::jit_lock_);
// Update to interpreter the methods that have baseline entrypoints and whose baseline
// hotness count is zero.
// Note that these methods may be in thread stack or concurrently revived
// between. That's OK, as the thread executing it will mark it.
for (auto it : profiling_infos_) {
ProfilingInfo* info = it.second;
if (info->GetBaselineHotnessCount() == 0) {
const void* entry_point = info->GetMethod()->GetEntryPointFromQuickCompiledCode();
if (ContainsPc(entry_point)) {
OatQuickMethodHeader* method_header =
OatQuickMethodHeader::FromEntryPoint(entry_point);
if (CodeInfo::IsBaseline(method_header->GetOptimizedCodeInfoPtr())) {
info->GetMethod()->SetEntryPointFromQuickCompiledCode(GetQuickToInterpreterBridge());
}
}
}
}
// TODO: collect profiling info
// TODO: collect optimized code
// Mark compiled code that are entrypoints of ArtMethods. Compiled code that is not
// an entry point is either:
// - an osr compiled code, that will be removed if not in a thread call stack.
// - discarded compiled code, that will be removed if not in a thread call stack.
for (const auto& entry : jni_stubs_map_) {
const JniStubData& data = entry.second;
const void* code_ptr = data.GetCode();
if (IsInZygoteExecSpace(code_ptr)) {
continue;
}
const OatQuickMethodHeader* method_header = OatQuickMethodHeader::FromCodePointer(code_ptr);
for (ArtMethod* method : data.GetMethods()) {
if (method_header->GetEntryPoint() == method->GetEntryPointFromQuickCompiledCode()) {
GetLiveBitmap()->AtomicTestAndSet(FromCodeToAllocation(code_ptr));
break;
}
}
}
for (const auto& it : method_code_map_) {
ArtMethod* method = it.second;
const void* code_ptr = it.first;
if (IsInZygoteExecSpace(code_ptr)) {
continue;
}
const OatQuickMethodHeader* method_header = OatQuickMethodHeader::FromCodePointer(code_ptr);
if (method_header->GetEntryPoint() == method->GetEntryPointFromQuickCompiledCode()) {
GetLiveBitmap()->AtomicTestAndSet(FromCodeToAllocation(code_ptr));
}
}
// Empty osr method map, as osr compiled code will be deleted (except the ones
// on thread stacks).
osr_code_map_.clear();
}
// Run a checkpoint on all threads to mark the JIT compiled code they are running.
MarkCompiledCodeOnThreadStacks(self);
// At this point, mutator threads are still running, and entrypoints of methods can
// change. We do know they cannot change to a code cache entry that is not marked,
// therefore we can safely remove those entries.
RemoveUnmarkedCode(self);
if (collect_profiling_info) {
// TODO: Collect unused profiling infos.
}
}
OatQuickMethodHeader* JitCodeCache::LookupMethodHeader(uintptr_t pc, ArtMethod* method) {
static_assert(kRuntimeISA != InstructionSet::kThumb2, "kThumb2 cannot be a runtime ISA");
if (kRuntimeISA == InstructionSet::kArm) {
// On Thumb-2, the pc is offset by one.
--pc;
}
if (!ContainsPc(reinterpret_cast<const void*>(pc))) {
return nullptr;
}
if (!kIsDebugBuild) {
// Called with null `method` only from MarkCodeClosure::Run() in debug build.
CHECK(method != nullptr);
}
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
OatQuickMethodHeader* method_header = nullptr;
ArtMethod* found_method = nullptr; // Only for DCHECK(), not for JNI stubs.
if (method != nullptr && UNLIKELY(method->IsNative())) {
auto it = jni_stubs_map_.find(JniStubKey(method));
if (it == jni_stubs_map_.end() || !ContainsElement(it->second.GetMethods(), method)) {
return nullptr;
}
const void* code_ptr = it->second.GetCode();
method_header = OatQuickMethodHeader::FromCodePointer(code_ptr);
if (!method_header->Contains(pc)) {
return nullptr;
}
} else {
if (shared_region_.IsInExecSpace(reinterpret_cast<const void*>(pc))) {
const void* code_ptr = zygote_map_.GetCodeFor(method, pc);
if (code_ptr != nullptr) {
return OatQuickMethodHeader::FromCodePointer(code_ptr);
}
}
auto it = method_code_map_.lower_bound(reinterpret_cast<const void*>(pc));
if (it != method_code_map_.begin()) {
--it;
const void* code_ptr = it->first;
if (OatQuickMethodHeader::FromCodePointer(code_ptr)->Contains(pc)) {
method_header = OatQuickMethodHeader::FromCodePointer(code_ptr);
found_method = it->second;
}
}
if (method_header == nullptr && method == nullptr) {
// Scan all compiled JNI stubs as well. This slow search is used only
// for checks in debug build, for release builds the `method` is not null.
for (auto&& entry : jni_stubs_map_) {
const JniStubData& data = entry.second;
if (data.IsCompiled() &&
OatQuickMethodHeader::FromCodePointer(data.GetCode())->Contains(pc)) {
method_header = OatQuickMethodHeader::FromCodePointer(data.GetCode());
}
}
}
if (method_header == nullptr) {
return nullptr;
}
}
if (kIsDebugBuild && method != nullptr && !method->IsNative()) {
DCHECK_EQ(found_method, method)
<< ArtMethod::PrettyMethod(method) << " "
<< ArtMethod::PrettyMethod(found_method) << " "
<< std::hex << pc;
}
return method_header;
}
OatQuickMethodHeader* JitCodeCache::LookupOsrMethodHeader(ArtMethod* method) {
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
auto it = osr_code_map_.find(method);
if (it == osr_code_map_.end()) {
return nullptr;
}
return OatQuickMethodHeader::FromCodePointer(it->second);
}
ProfilingInfo* JitCodeCache::AddProfilingInfo(Thread* self,
ArtMethod* method,
const std::vector<uint32_t>& entries) {
DCHECK(CanAllocateProfilingInfo());
ProfilingInfo* info = nullptr;
{
MutexLock mu(self, *Locks::jit_lock_);
info = AddProfilingInfoInternal(self, method, entries);
}
if (info == nullptr) {
GarbageCollectCache(self);
MutexLock mu(self, *Locks::jit_lock_);
info = AddProfilingInfoInternal(self, method, entries);
}
return info;
}
ProfilingInfo* JitCodeCache::AddProfilingInfoInternal(Thread* self ATTRIBUTE_UNUSED,
ArtMethod* method,
const std::vector<uint32_t>& entries) {
// Check whether some other thread has concurrently created it.
auto it = profiling_infos_.find(method);
if (it != profiling_infos_.end()) {
return it->second;
}
size_t profile_info_size = RoundUp(
sizeof(ProfilingInfo) + sizeof(InlineCache) * entries.size(),
sizeof(void*));
const uint8_t* data = private_region_.AllocateData(profile_info_size);
if (data == nullptr) {
return nullptr;
}
uint8_t* writable_data = private_region_.GetWritableDataAddress(data);
ProfilingInfo* info = new (writable_data) ProfilingInfo(method, entries);
profiling_infos_.Put(method, info);
histogram_profiling_info_memory_use_.AddValue(profile_info_size);
return info;
}
void* JitCodeCache::MoreCore(const void* mspace, intptr_t increment) {
return shared_region_.OwnsSpace(mspace)
? shared_region_.MoreCore(mspace, increment)
: private_region_.MoreCore(mspace, increment);
}
void JitCodeCache::GetProfiledMethods(const std::set<std::string>& dex_base_locations,
std::vector<ProfileMethodInfo>& methods) {
Thread* self = Thread::Current();
WaitUntilInlineCacheAccessible(self);
MutexLock mu(self, *Locks::jit_lock_);
ScopedTrace trace(__FUNCTION__);
uint16_t jit_compile_threshold = Runtime::Current()->GetJITOptions()->GetCompileThreshold();
for (auto it : profiling_infos_) {
ProfilingInfo* info = it.second;
ArtMethod* method = info->GetMethod();
const DexFile* dex_file = method->GetDexFile();
const std::string base_location = DexFileLoader::GetBaseLocation(dex_file->GetLocation());
if (!ContainsElement(dex_base_locations, base_location)) {
// Skip dex files which are not profiled.
continue;
}
std::vector<ProfileMethodInfo::ProfileInlineCache> inline_caches;
// If the method didn't reach the compilation threshold don't save the inline caches.
// They might be incomplete and cause unnecessary deoptimizations.
// If the inline cache is empty the compiler will generate a regular invoke virtual/interface.
if (method->GetCounter() < jit_compile_threshold) {
methods.emplace_back(/*ProfileMethodInfo*/
MethodReference(dex_file, method->GetDexMethodIndex()), inline_caches);
continue;
}
for (size_t i = 0; i < info->number_of_inline_caches_; ++i) {
std::vector<TypeReference> profile_classes;
const InlineCache& cache = info->cache_[i];
ArtMethod* caller = info->GetMethod();
bool is_missing_types = false;
for (size_t k = 0; k < InlineCache::kIndividualCacheSize; k++) {
mirror::Class* cls = cache.classes_[k].Read();
if (cls == nullptr) {
break;
}
// Check if the receiver is in the boot class path or if it's in the
// same class loader as the caller. If not, skip it, as there is not
// much we can do during AOT.
if (!cls->IsBootStrapClassLoaded() &&
caller->GetClassLoader() != cls->GetClassLoader()) {
is_missing_types = true;
continue;
}
const DexFile* class_dex_file = nullptr;
dex::TypeIndex type_index;
if (cls->GetDexCache() == nullptr) {
DCHECK(cls->IsArrayClass()) << cls->PrettyClass();
// Make a best effort to find the type index in the method's dex file.
// We could search all open dex files but that might turn expensive
// and probably not worth it.
class_dex_file = dex_file;
type_index = cls->FindTypeIndexInOtherDexFile(*dex_file);
} else {
class_dex_file = &(cls->GetDexFile());
type_index = cls->GetDexTypeIndex();
}
if (!type_index.IsValid()) {
// Could be a proxy class or an array for which we couldn't find the type index.
is_missing_types = true;
continue;
}
if (ContainsElement(dex_base_locations,
DexFileLoader::GetBaseLocation(class_dex_file->GetLocation()))) {
// Only consider classes from the same apk (including multidex).
profile_classes.emplace_back(/*ProfileMethodInfo::ProfileClassReference*/
class_dex_file, type_index);
} else {
is_missing_types = true;
}
}
if (!profile_classes.empty()) {
inline_caches.emplace_back(/*ProfileMethodInfo::ProfileInlineCache*/
cache.dex_pc_, is_missing_types, profile_classes);
}
}
methods.emplace_back(/*ProfileMethodInfo*/
MethodReference(dex_file, method->GetDexMethodIndex()), inline_caches);
}
}
bool JitCodeCache::IsOsrCompiled(ArtMethod* method) {
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
return osr_code_map_.find(method) != osr_code_map_.end();
}
bool JitCodeCache::NotifyCompilationOf(ArtMethod* method,
Thread* self,
CompilationKind compilation_kind,
bool prejit) {
const void* existing_entry_point = method->GetEntryPointFromQuickCompiledCode();
if (compilation_kind != CompilationKind::kOsr && ContainsPc(existing_entry_point)) {
OatQuickMethodHeader* method_header =
OatQuickMethodHeader::FromEntryPoint(existing_entry_point);
bool is_baseline = (compilation_kind == CompilationKind::kBaseline);
if (CodeInfo::IsBaseline(method_header->GetOptimizedCodeInfoPtr()) == is_baseline) {
VLOG(jit) << "Not compiling "
<< method->PrettyMethod()
<< " because it has already been compiled"
<< " kind=" << compilation_kind;
return false;
}
}
if (NeedsClinitCheckBeforeCall(method) && !prejit) {
// We do not need a synchronization barrier for checking the visibly initialized status
// or checking the initialized status just for requesting visible initialization.
ClassStatus status = method->GetDeclaringClass()
->GetStatus<kDefaultVerifyFlags, /*kWithSynchronizationBarrier=*/ false>();
if (status != ClassStatus::kVisiblyInitialized) {
// Unless we're pre-jitting, we currently don't save the JIT compiled code if we cannot
// update the entrypoint due to needing an initialization check.
if (status == ClassStatus::kInitialized) {
// Request visible initialization but do not block to allow compiling other methods.
// Hopefully, this will complete by the time the method becomes hot again.
Runtime::Current()->GetClassLinker()->MakeInitializedClassesVisiblyInitialized(
self, /*wait=*/ false);
}
VLOG(jit) << "Not compiling "
<< method->PrettyMethod()
<< " because it has the resolution stub";
// Give it a new chance to be hot.
ClearMethodCounter(method, /*was_warm=*/ false);
return false;
}
}
if (compilation_kind == CompilationKind::kOsr) {
MutexLock mu(self, *Locks::jit_lock_);
if (osr_code_map_.find(method) != osr_code_map_.end()) {
return false;
}
}
if (UNLIKELY(method->IsNative())) {
MutexLock mu(self, *Locks::jit_lock_);
JniStubKey key(method);
auto it = jni_stubs_map_.find(key);
bool new_compilation = false;
if (it == jni_stubs_map_.end()) {
// Create a new entry to mark the stub as being compiled.
it = jni_stubs_map_.Put(key, JniStubData{});
new_compilation = true;
}
JniStubData* data = &it->second;
data->AddMethod(method);
if (data->IsCompiled()) {
OatQuickMethodHeader* method_header = OatQuickMethodHeader::FromCodePointer(data->GetCode());
const void* entrypoint = method_header->GetEntryPoint();
// Update also entrypoints of other methods held by the JniStubData.
// We could simply update the entrypoint of `method` but if the last JIT GC has
// changed these entrypoints to GenericJNI in preparation for a full GC, we may
// as well change them back as this stub shall not be collected anyway and this
// can avoid a few expensive GenericJNI calls.
data->UpdateEntryPoints(entrypoint);
if (collection_in_progress_) {
if (!IsInZygoteExecSpace(data->GetCode())) {
GetLiveBitmap()->AtomicTestAndSet(FromCodeToAllocation(data->GetCode()));
}
}
}
return new_compilation;
} else {
if (CanAllocateProfilingInfo() && (compilation_kind == CompilationKind::kBaseline)) {
bool has_profiling_info = false;
{
MutexLock mu(self, *Locks::jit_lock_);
has_profiling_info = (profiling_infos_.find(method) != profiling_infos_.end());
}
if (!has_profiling_info) {
if (ProfilingInfo::Create(self, method) == nullptr) {
VLOG(jit) << method->PrettyMethod() << " needs a ProfilingInfo to be compiled baseline";
ClearMethodCounter(method, /*was_warm=*/ false);
return false;
}
}
}
MutexLock mu(self, *Locks::jit_lock_);
if (IsMethodBeingCompiled(method, compilation_kind)) {
return false;
}
AddMethodBeingCompiled(method, compilation_kind);
return true;
}
}
ProfilingInfo* JitCodeCache::NotifyCompilerUse(ArtMethod* method, Thread* self) {
MutexLock mu(self, *Locks::jit_lock_);
auto it = profiling_infos_.find(method);
if (it == profiling_infos_.end()) {
return nullptr;
}
if (!it->second->IncrementInlineUse()) {
// Overflow of inlining uses, just bail.
return nullptr;
}
return it->second;
}
void JitCodeCache::DoneCompilerUse(ArtMethod* method, Thread* self) {
MutexLock mu(self, *Locks::jit_lock_);
auto it = profiling_infos_.find(method);
DCHECK(it != profiling_infos_.end());
it->second->DecrementInlineUse();
}
void JitCodeCache::DoneCompiling(ArtMethod* method,
Thread* self,
CompilationKind compilation_kind) {
DCHECK_EQ(Thread::Current(), self);
MutexLock mu(self, *Locks::jit_lock_);
if (UNLIKELY(method->IsNative())) {
auto it = jni_stubs_map_.find(JniStubKey(method));
DCHECK(it != jni_stubs_map_.end());
JniStubData* data = &it->second;
DCHECK(ContainsElement(data->GetMethods(), method));
if (UNLIKELY(!data->IsCompiled())) {
// Failed to compile; the JNI compiler never fails, but the cache may be full.
jni_stubs_map_.erase(it); // Remove the entry added in NotifyCompilationOf().
} // else Commit() updated entrypoints of all methods in the JniStubData.
} else {
RemoveMethodBeingCompiled(method, compilation_kind);
}
}
void JitCodeCache::InvalidateAllCompiledCode() {
art::MutexLock mu(Thread::Current(), *Locks::jit_lock_);
VLOG(jit) << "Invalidating all compiled code";
ClassLinker* linker = Runtime::Current()->GetClassLinker();
for (auto it : method_code_map_) {
ArtMethod* meth = it.second;
// We were compiled, so we must be warm.
ClearMethodCounter(meth, /*was_warm=*/true);
if (meth->IsObsolete()) {
linker->SetEntryPointsForObsoleteMethod(meth);
} else {
linker->SetEntryPointsToInterpreter(meth);
}
}
saved_compiled_methods_map_.clear();
osr_code_map_.clear();
}
void JitCodeCache::InvalidateCompiledCodeFor(ArtMethod* method,
const OatQuickMethodHeader* header) {
DCHECK(!method->IsNative());
const void* method_entrypoint = method->GetEntryPointFromQuickCompiledCode();
// Clear the method counter if we are running jitted code since we might want to jit this again in
// the future.
if (method_entrypoint == header->GetEntryPoint()) {
// The entrypoint is the one to invalidate, so we just update it to the interpreter entry point
// and clear the counter to get the method Jitted again.
Runtime::Current()->GetInstrumentation()->UpdateMethodsCode(
method, GetQuickToInterpreterBridge());
ClearMethodCounter(method, /*was_warm=*/ true);
} else {
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
auto it = osr_code_map_.find(method);
if (it != osr_code_map_.end() && OatQuickMethodHeader::FromCodePointer(it->second) == header) {
// Remove the OSR method, to avoid using it again.
osr_code_map_.erase(it);
}
}
// In case the method was pre-compiled, clear that information so we
// can recompile it ourselves.
if (method->IsPreCompiled()) {
method->ClearPreCompiled();
}
}
void JitCodeCache::Dump(std::ostream& os) {
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
os << "Current JIT code cache size (used / resident): "
<< GetCurrentRegion()->GetUsedMemoryForCode() / KB << "KB / "
<< GetCurrentRegion()->GetResidentMemoryForCode() / KB << "KB\n"
<< "Current JIT data cache size (used / resident): "
<< GetCurrentRegion()->GetUsedMemoryForData() / KB << "KB / "
<< GetCurrentRegion()->GetResidentMemoryForData() / KB << "KB\n";
if (!Runtime::Current()->IsZygote()) {
os << "Zygote JIT code cache size (at point of fork): "
<< shared_region_.GetUsedMemoryForCode() / KB << "KB / "
<< shared_region_.GetResidentMemoryForCode() / KB << "KB\n"
<< "Zygote JIT data cache size (at point of fork): "
<< shared_region_.GetUsedMemoryForData() / KB << "KB / "
<< shared_region_.GetResidentMemoryForData() / KB << "KB\n";
}
os << "Current JIT mini-debug-info size: " << PrettySize(GetJitMiniDebugInfoMemUsage()) << "\n"
<< "Current JIT capacity: " << PrettySize(GetCurrentRegion()->GetCurrentCapacity()) << "\n"
<< "Current number of JIT JNI stub entries: " << jni_stubs_map_.size() << "\n"
<< "Current number of JIT code cache entries: " << method_code_map_.size() << "\n"
<< "Total number of JIT baseline compilations: " << number_of_baseline_compilations_ << "\n"
<< "Total number of JIT optimized compilations: " << number_of_optimized_compilations_ << "\n"
<< "Total number of JIT compilations for on stack replacement: "
<< number_of_osr_compilations_ << "\n"
<< "Total number of JIT code cache collections: " << number_of_collections_ << std::endl;
histogram_stack_map_memory_use_.PrintMemoryUse(os);
histogram_code_memory_use_.PrintMemoryUse(os);
histogram_profiling_info_memory_use_.PrintMemoryUse(os);
}
void JitCodeCache::PostForkChildAction(bool is_system_server, bool is_zygote) {
Thread* self = Thread::Current();
// Remove potential tasks that have been inherited from the zygote.
// We do this now and not in Jit::PostForkChildAction, as system server calls
// JitCodeCache::PostForkChildAction first, and then does some code loading
// that may result in new JIT tasks that we want to keep.
ThreadPool* pool = Runtime::Current()->GetJit()->GetThreadPool();
if (pool != nullptr) {
pool->RemoveAllTasks(self);
}
MutexLock mu(self, *Locks::jit_lock_);
// Reset potential writable MemMaps inherited from the zygote. We never want
// to write to them.
shared_region_.ResetWritableMappings();
if (is_zygote || Runtime::Current()->IsSafeMode()) {
// Don't create a private region for a child zygote. Regions are usually map shared
// (to satisfy dual-view), and we don't want children of a child zygote to inherit it.
return;
}
// Reset all statistics to be specific to this process.
number_of_baseline_compilations_ = 0;
number_of_optimized_compilations_ = 0;
number_of_osr_compilations_ = 0;
number_of_collections_ = 0;
histogram_stack_map_memory_use_.Reset();
histogram_code_memory_use_.Reset();
histogram_profiling_info_memory_use_.Reset();
size_t initial_capacity = Runtime::Current()->GetJITOptions()->GetCodeCacheInitialCapacity();
size_t max_capacity = Runtime::Current()->GetJITOptions()->GetCodeCacheMaxCapacity();
std::string error_msg;
if (!private_region_.Initialize(initial_capacity,
max_capacity,
/* rwx_memory_allowed= */ !is_system_server,
is_zygote,
&error_msg)) {
LOG(WARNING) << "Could not create private region after zygote fork: " << error_msg;
}
}
JitMemoryRegion* JitCodeCache::GetCurrentRegion() {
return Runtime::Current()->IsZygote() ? &shared_region_ : &private_region_;
}
void JitCodeCache::VisitAllMethods(const std::function<void(const void*, ArtMethod*)>& cb) {
for (const auto& it : jni_stubs_map_) {
const JniStubData& data = it.second;
if (data.IsCompiled()) {
for (ArtMethod* method : data.GetMethods()) {
cb(data.GetCode(), method);
}
}
}
for (auto it : method_code_map_) { // Includes OSR methods.
cb(it.first, it.second);
}
for (auto it : saved_compiled_methods_map_) {
cb(it.second, it.first);
}
for (auto it : zygote_map_) {
if (it.code_ptr != nullptr && it.method != nullptr) {
cb(it.code_ptr, it.method);
}
}
}
void ZygoteMap::Initialize(uint32_t number_of_methods) {
MutexLock mu(Thread::Current(), *Locks::jit_lock_);
// Allocate for 40-80% capacity. This will offer OK lookup times, and termination
// cases.
size_t capacity = RoundUpToPowerOfTwo(number_of_methods * 100 / 80);
const uint8_t* memory = region_->AllocateData(
capacity * sizeof(Entry) + sizeof(ZygoteCompilationState));
if (memory == nullptr) {
LOG(WARNING) << "Could not allocate data for the zygote map";
return;
}
const Entry* data = reinterpret_cast<const Entry*>(memory);
region_->FillData(data, capacity, Entry { nullptr, nullptr });
map_ = ArrayRef(data, capacity);
compilation_state_ = reinterpret_cast<const ZygoteCompilationState*>(
memory + capacity * sizeof(Entry));
region_->WriteData(compilation_state_, ZygoteCompilationState::kInProgress);
}
const void* ZygoteMap::GetCodeFor(ArtMethod* method, uintptr_t pc) const {
if (map_.empty()) {
return nullptr;
}
if (method == nullptr) {
// Do a linear search. This should only be used in debug builds.
CHECK(kIsDebugBuild);
for (const Entry& entry : map_) {
const void* code_ptr = entry.code_ptr;
if (code_ptr != nullptr) {
OatQuickMethodHeader* method_header = OatQuickMethodHeader::FromCodePointer(code_ptr);
if (method_header->Contains(pc)) {
return code_ptr;
}
}
}
return nullptr;
}
std::hash<ArtMethod*> hf;
size_t index = hf(method) & (map_.size() - 1u);
size_t original_index = index;
// Loop over the array: we know this loop terminates as we will either
// encounter the given method, or a null entry. Both terminate the loop.
// Note that the zygote may concurrently write new entries to the map. That's OK as the
// map is never resized.
while (true) {
const Entry& entry = map_[index];
if (entry.method == nullptr) {
// Not compiled yet.
return nullptr;
}
if (entry.method == method) {
if (entry.code_ptr == nullptr) {
// This is a race with the zygote which wrote the method, but hasn't written the
// code. Just bail and wait for the next time we need the method.
return nullptr;
}
if (pc != 0 && !OatQuickMethodHeader::FromCodePointer(entry.code_ptr)->Contains(pc)) {
return nullptr;
}
return entry.code_ptr;
}
index = (index + 1) & (map_.size() - 1);
DCHECK_NE(original_index, index);
}
}
void ZygoteMap::Put(const void* code, ArtMethod* method) {
if (map_.empty()) {
return;
}
CHECK(Runtime::Current()->IsZygote());
std::hash<ArtMethod*> hf;
size_t index = hf(method) & (map_.size() - 1);
size_t original_index = index;
// Because the size of the map is bigger than the number of methods that will
// be added, we are guaranteed to find a free slot in the array, and
// therefore for this loop to terminate.
while (true) {
const Entry* entry = &map_[index];
if (entry->method == nullptr) {
// Note that readers can read this memory concurrently, but that's OK as
// we are writing pointers.
region_->WriteData(entry, Entry { method, code });
break;
}
index = (index + 1) & (map_.size() - 1);
DCHECK_NE(original_index, index);
}
DCHECK_EQ(GetCodeFor(method), code);
}
} // namespace jit
} // namespace art