/*
* 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 <android-base/unique_fd.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/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 "instrumentation.h"
#include "intern_table.h"
#include "jit/jit.h"
#include "jit/profiling_info.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"
using android::base::unique_fd;
namespace art {
namespace jit {
static constexpr size_t kCodeSizeLogThreshold = 50 * KB;
static constexpr size_t kStackMapSizeLogThreshold = 50 * KB;
// Data cache will be half of the capacity
// Code cache will be the other half of the capacity.
// TODO: Make this variable?
static constexpr size_t kCodeAndDataCapacityDivider = 2;
static constexpr int kProtR = PROT_READ;
static constexpr int kProtRW = PROT_READ | PROT_WRITE;
static constexpr int kProtRWX = PROT_READ | PROT_WRITE | PROT_EXEC;
static constexpr int kProtRX = PROT_READ | PROT_EXEC;
namespace {
// Translate an address belonging to one memory map into an address in a second. This is useful
// when there are two virtual memory ranges for the same physical memory range.
template <typename T>
T* TranslateAddress(T* src_ptr, const MemMap& src, const MemMap& dst) {
CHECK(src.HasAddress(src_ptr));
uint8_t* const raw_src_ptr = reinterpret_cast<uint8_t*>(src_ptr);
return reinterpret_cast<T*>(raw_src_ptr - src.Begin() + dst.Begin());
}
} // namespace
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;
}
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) {
auto kept_end = std::remove_if(
methods_.begin(),
methods_.end(),
[&alloc](ArtMethod* method) { return alloc.ContainsUnsafe(method); });
methods_.erase(kept_end, methods_.end());
}
bool RemoveMethod(ArtMethod* method) {
auto it = std::find(methods_.begin(), methods_.end(), method);
if (it != methods_.end()) {
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_;
};
bool JitCodeCache::InitializeMappings(bool rwx_memory_allowed,
bool is_zygote,
std::string* error_msg) {
ScopedTrace trace(__PRETTY_FUNCTION__);
const size_t capacity = max_capacity_;
const size_t data_capacity = capacity / kCodeAndDataCapacityDivider;
const size_t exec_capacity = capacity - data_capacity;
// File descriptor enabling dual-view mapping of code section.
unique_fd mem_fd;
// Zygote shouldn't create a shared mapping for JIT, so we cannot use dual view
// for it.
if (!is_zygote) {
// Bionic supports memfd_create, but the call may fail on older kernels.
mem_fd = unique_fd(art::memfd_create("/jit-cache", /* flags= */ 0));
if (mem_fd.get() < 0) {
std::ostringstream oss;
oss << "Failed to initialize dual view JIT. memfd_create() error: " << strerror(errno);
if (!rwx_memory_allowed) {
// Without using RWX page permissions, the JIT can not fallback to single mapping as it
// requires tranitioning the code pages to RWX for updates.
*error_msg = oss.str();
return false;
}
VLOG(jit) << oss.str();
}
}
if (mem_fd.get() >= 0 && ftruncate(mem_fd, capacity) != 0) {
std::ostringstream oss;
oss << "Failed to initialize memory file: " << strerror(errno);
*error_msg = oss.str();
return false;
}
std::string data_cache_name = is_zygote ? "zygote-data-code-cache" : "data-code-cache";
std::string exec_cache_name = is_zygote ? "zygote-jit-code-cache" : "jit-code-cache";
std::string error_str;
// Map name specific for android_os_Debug.cpp accounting.
// Map in low 4gb to simplify accessing root tables for x86_64.
// We could do PC-relative addressing to avoid this problem, but that
// would require reserving code and data area before submitting, which
// means more windows for the code memory to be RWX.
int base_flags;
MemMap data_pages;
if (mem_fd.get() >= 0) {
// Dual view of JIT code cache case. Create an initial mapping of data pages large enough
// for data and non-writable view of JIT code pages. We use the memory file descriptor to
// enable dual mapping - we'll create a second mapping using the descriptor below. The
// mappings will look like:
//
// VA PA
//
// +---------------+
// | non exec code |\
// +---------------+ \
// : :\ \
// +---------------+.\.+---------------+
// | exec code | \| code |
// +---------------+...+---------------+
// | data | | data |
// +---------------+...+---------------+
//
// In this configuration code updates are written to the non-executable view of the code
// cache, and the executable view of the code cache has fixed RX memory protections.
//
// This memory needs to be mapped shared as the code portions will have two mappings.
base_flags = MAP_SHARED;
data_pages = MemMap::MapFile(
data_capacity + exec_capacity,
kProtRW,
base_flags,
mem_fd,
/* start= */ 0,
/* low_4gb= */ true,
data_cache_name.c_str(),
&error_str);
} else {
// Single view of JIT code cache case. Create an initial mapping of data pages large enough
// for data and JIT code pages. The mappings will look like:
//
// VA PA
//
// +---------------+...+---------------+
// | exec code | | code |
// +---------------+...+---------------+
// | data | | data |
// +---------------+...+---------------+
//
// In this configuration code updates are written to the executable view of the code cache,
// and the executable view of the code cache transitions RX to RWX for the update and then
// back to RX after the update.
base_flags = MAP_PRIVATE | MAP_ANON;
data_pages = MemMap::MapAnonymous(
data_cache_name.c_str(),
data_capacity + exec_capacity,
kProtRW,
/* low_4gb= */ true,
&error_str);
}
if (!data_pages.IsValid()) {
std::ostringstream oss;
oss << "Failed to create read write cache: " << error_str << " size=" << capacity;
*error_msg = oss.str();
return false;
}
MemMap exec_pages;
MemMap non_exec_pages;
if (exec_capacity > 0) {
uint8_t* const divider = data_pages.Begin() + data_capacity;
// Set initial permission for executable view to catch any SELinux permission problems early
// (for processes that cannot map WX pages). Otherwise, this region does not need to be
// executable as there is no code in the cache yet.
exec_pages = data_pages.RemapAtEnd(divider,
exec_cache_name.c_str(),
kProtRX,
base_flags | MAP_FIXED,
mem_fd.get(),
(mem_fd.get() >= 0) ? data_capacity : 0,
&error_str);
if (!exec_pages.IsValid()) {
std::ostringstream oss;
oss << "Failed to create read execute code cache: " << error_str << " size=" << capacity;
*error_msg = oss.str();
return false;
}
if (mem_fd.get() >= 0) {
// For dual view, create the secondary view of code memory used for updating code. This view
// is never executable.
std::string name = exec_cache_name + "-rw";
non_exec_pages = MemMap::MapFile(exec_capacity,
kProtR,
base_flags,
mem_fd,
/* start= */ data_capacity,
/* low_4GB= */ false,
name.c_str(),
&error_str);
if (!non_exec_pages.IsValid()) {
static const char* kFailedNxView = "Failed to map non-executable view of JIT code cache";
if (rwx_memory_allowed) {
// Log and continue as single view JIT (requires RWX memory).
VLOG(jit) << kFailedNxView;
} else {
*error_msg = kFailedNxView;
return false;
}
}
}
} else {
// Profiling only. No memory for code required.
}
data_pages_ = std::move(data_pages);
exec_pages_ = std::move(exec_pages);
non_exec_pages_ = std::move(non_exec_pages);
return true;
}
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";
}
}
// 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;
}
size_t initial_capacity = Runtime::Current()->GetJITOptions()->GetCodeCacheInitialCapacity();
std::unique_ptr<JitCodeCache> jit_code_cache(new JitCodeCache());
MutexLock mu(Thread::Current(), jit_code_cache->lock_);
jit_code_cache->InitializeState(initial_capacity, max_capacity);
// Zygote should never collect code to share the memory with the children.
if (is_zygote) {
jit_code_cache->garbage_collect_code_ = false;
}
if (!jit_code_cache->InitializeMappings(rwx_memory_allowed, is_zygote, error_msg)) {
return nullptr;
}
jit_code_cache->InitializeSpaces();
VLOG(jit) << "Created jit code cache: initial capacity="
<< PrettySize(initial_capacity)
<< ", maximum capacity="
<< PrettySize(max_capacity);
return jit_code_cache.release();
}
JitCodeCache::JitCodeCache()
: lock_("Jit code cache", kJitCodeCacheLock),
lock_cond_("Jit code cache condition variable", lock_),
collection_in_progress_(false),
last_collection_increased_code_cache_(false),
garbage_collect_code_(true),
used_memory_for_data_(0),
used_memory_for_code_(0),
number_of_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),
is_weak_access_enabled_(true),
inline_cache_cond_("Jit inline cache condition variable", lock_),
zygote_data_pages_(),
zygote_exec_pages_(),
zygote_data_mspace_(nullptr),
zygote_exec_mspace_(nullptr) {
}
void JitCodeCache::InitializeState(size_t initial_capacity, size_t max_capacity) {
CHECK_GE(max_capacity, initial_capacity);
CHECK(max_capacity <= 1 * GB) << "The max supported size for JIT code cache is 1GB";
// Align both capacities to page size, as that's the unit mspaces use.
initial_capacity = RoundDown(initial_capacity, 2 * kPageSize);
max_capacity = RoundDown(max_capacity, 2 * kPageSize);
used_memory_for_data_ = 0;
used_memory_for_code_ = 0;
number_of_compilations_ = 0;
number_of_osr_compilations_ = 0;
number_of_collections_ = 0;
data_pages_ = MemMap();
exec_pages_ = MemMap();
non_exec_pages_ = MemMap();
initial_capacity_ = initial_capacity;
max_capacity_ = max_capacity;
current_capacity_ = initial_capacity,
data_end_ = initial_capacity / kCodeAndDataCapacityDivider;
exec_end_ = initial_capacity - data_end_;
}
void JitCodeCache::InitializeSpaces() {
// Initialize the data heap
data_mspace_ = create_mspace_with_base(data_pages_.Begin(), data_end_, false /*locked*/);
CHECK(data_mspace_ != nullptr) << "create_mspace_with_base (data) failed";
// Initialize the code heap
MemMap* code_heap = nullptr;
if (non_exec_pages_.IsValid()) {
code_heap = &non_exec_pages_;
} else if (exec_pages_.IsValid()) {
code_heap = &exec_pages_;
}
if (code_heap != nullptr) {
// Make all pages reserved for the code heap writable. The mspace allocator, that manages the
// heap, will take and initialize pages in create_mspace_with_base().
CheckedCall(mprotect, "create code heap", code_heap->Begin(), code_heap->Size(), kProtRW);
exec_mspace_ = create_mspace_with_base(code_heap->Begin(), exec_end_, false /*locked*/);
CHECK(exec_mspace_ != nullptr) << "create_mspace_with_base (exec) failed";
SetFootprintLimit(initial_capacity_);
// Protect pages containing heap metadata. Updates to the code heap toggle write permission to
// perform the update and there are no other times write access is required.
CheckedCall(mprotect, "protect code heap", code_heap->Begin(), code_heap->Size(), kProtR);
} else {
exec_mspace_ = nullptr;
SetFootprintLimit(initial_capacity_);
}
}
JitCodeCache::~JitCodeCache() {}
bool JitCodeCache::ContainsPc(const void* ptr) const {
return exec_pages_.HasAddress(ptr) || zygote_exec_pages_.HasAddress(ptr);
}
bool JitCodeCache::WillExecuteJitCode(ArtMethod* method) {
ScopedObjectAccess soa(art::Thread::Current());
ScopedAssertNoThreadSuspension sants(__FUNCTION__);
if (ContainsPc(method->GetEntryPointFromQuickCompiledCode())) {
return true;
} else if (method->GetEntryPointFromQuickCompiledCode() == GetQuickInstrumentationEntryPoint()) {
return FindCompiledCodeForInstrumentation(method) != nullptr;
}
return false;
}
bool JitCodeCache::ContainsMethod(ArtMethod* method) {
MutexLock mu(Thread::Current(), 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;
}
}
}
return false;
}
const void* JitCodeCache::GetJniStubCode(ArtMethod* method) {
DCHECK(method->IsNative());
MutexLock mu(Thread::Current(), 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::FindCompiledCodeForInstrumentation(ArtMethod* method) {
// If jit-gc is still on we use the SavedEntryPoint field for doing that and so cannot use it to
// find the instrumentation entrypoint.
if (LIKELY(GetGarbageCollectCode())) {
return nullptr;
}
ProfilingInfo* info = method->GetProfilingInfo(kRuntimePointerSize);
if (info == nullptr) {
return nullptr;
}
// When GC is disabled for trampoline tracing we will use SavedEntrypoint to hold the actual
// jit-compiled version of the method. If jit-gc is disabled for other reasons this will just be
// nullptr.
return info->GetSavedEntryPoint();
}
const void* JitCodeCache::GetZygoteSavedEntryPoint(ArtMethod* method) {
if (Runtime::Current()->IsUsingApexBootImageLocation() &&
// Currently only applies to boot classpath
method->GetDeclaringClass()->GetClassLoader() == nullptr) {
const void* entry_point = nullptr;
if (method->IsNative()) {
const void* code_ptr = GetJniStubCode(method);
if (code_ptr != nullptr) {
entry_point = OatQuickMethodHeader::FromCodePointer(code_ptr)->GetEntryPoint();
}
} else {
ProfilingInfo* profiling_info = method->GetProfilingInfo(kRuntimePointerSize);
if (profiling_info != nullptr) {
entry_point = profiling_info->GetSavedEntryPoint();
}
}
if (Runtime::Current()->IsZygote() || IsInZygoteExecSpace(entry_point)) {
return entry_point;
}
}
return nullptr;
}
class ScopedCodeCacheWrite : ScopedTrace {
public:
explicit ScopedCodeCacheWrite(const JitCodeCache* const code_cache)
: ScopedTrace("ScopedCodeCacheWrite"),
code_cache_(code_cache) {
ScopedTrace trace("mprotect all");
const MemMap* const updatable_pages = code_cache_->GetUpdatableCodeMapping();
if (updatable_pages != nullptr) {
int prot = code_cache_->HasDualCodeMapping() ? kProtRW : kProtRWX;
CheckedCall(mprotect, "Cache +W", updatable_pages->Begin(), updatable_pages->Size(), prot);
}
}
~ScopedCodeCacheWrite() {
ScopedTrace trace("mprotect code");
const MemMap* const updatable_pages = code_cache_->GetUpdatableCodeMapping();
if (updatable_pages != nullptr) {
int prot = code_cache_->HasDualCodeMapping() ? kProtR : kProtRX;
CheckedCall(mprotect, "Cache -W", updatable_pages->Begin(), updatable_pages->Size(), prot);
}
}
private:
const JitCodeCache* const code_cache_;
DISALLOW_COPY_AND_ASSIGN(ScopedCodeCacheWrite);
};
uint8_t* JitCodeCache::CommitCode(Thread* self,
ArtMethod* method,
uint8_t* stack_map,
uint8_t* roots_data,
const uint8_t* code,
size_t code_size,
size_t data_size,
bool osr,
const std::vector<Handle<mirror::Object>>& roots,
bool has_should_deoptimize_flag,
const ArenaSet<ArtMethod*>& cha_single_implementation_list) {
uint8_t* result = CommitCodeInternal(self,
method,
stack_map,
roots_data,
code,
code_size,
data_size,
osr,
roots,
has_should_deoptimize_flag,
cha_single_implementation_list);
if (result == nullptr) {
// Retry.
GarbageCollectCache(self);
result = CommitCodeInternal(self,
method,
stack_map,
roots_data,
code,
code_size,
data_size,
osr,
roots,
has_should_deoptimize_flag,
cha_single_implementation_list);
}
return result;
}
bool JitCodeCache::WaitForPotentialCollectionToComplete(Thread* self) {
bool in_collection = false;
while (collection_in_progress_) {
in_collection = true;
lock_cond_.Wait(self);
}
return in_collection;
}
static size_t GetJitCodeAlignment() {
if (kRuntimeISA == InstructionSet::kArm || kRuntimeISA == InstructionSet::kThumb2) {
// Some devices with 32-bit ARM kernels need additional JIT code alignment when using dual
// view JIT (b/132205399). The alignment returned here coincides with the typical ARM d-cache
// line (though the value should be probed ideally). Both the method header and code in the
// cache are aligned to this size. Anything less than 64-bytes exhibits the problem.
return 64;
}
return GetInstructionSetAlignment(kRuntimeISA);
}
static uintptr_t FromCodeToAllocation(const void* code) {
size_t alignment = GetJitCodeAlignment();
return reinterpret_cast<uintptr_t>(code) - RoundUp(sizeof(OatQuickMethodHeader), alignment);
}
static uint32_t ComputeRootTableSize(uint32_t number_of_roots) {
return sizeof(uint32_t) + number_of_roots * sizeof(GcRoot<mirror::Object>);
}
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 FillRootTableLength(uint8_t* roots_data, uint32_t length) {
// Store the length of the table at the end. This will allow fetching it from a `stack_map`
// pointer.
reinterpret_cast<uint32_t*>(roots_data)[length] = length;
}
static const uint8_t* FromStackMapToRoots(const uint8_t* stack_map_data) {
return stack_map_data - ComputeRootTableSize(GetNumberOfRoots(stack_map_data));
}
static void DCheckRootsAreValid(const std::vector<Handle<mirror::Object>>& roots)
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);
}
}
}
void JitCodeCache::FillRootTable(uint8_t* roots_data,
const std::vector<Handle<mirror::Object>>& roots) {
GcRoot<mirror::Object>* gc_roots = reinterpret_cast<GcRoot<mirror::Object>*>(roots_data);
const uint32_t length = roots.size();
// Put all roots in `roots_data`.
for (uint32_t i = 0; i < length; ++i) {
ObjPtr<mirror::Object> object = roots[i].Get();
gc_roots[i] = GcRoot<mirror::Object>(object);
}
}
static 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);
}
// Use a sentinel for marking entries in the JIT table that have been cleared.
// This helps diagnosing in case the compiled code tries to wrongly access such
// entries.
static mirror::Class* const weak_sentinel =
reinterpret_cast<mirror::Class*>(Context::kBadGprBase + 0xff);
// Helper for the GC to process a weak class in a JIT root table.
static inline void ProcessWeakClass(GcRoot<mirror::Class>* root_ptr,
IsMarkedVisitor* visitor,
mirror::Class* update)
REQUIRES_SHARED(Locks::mutator_lock_) {
// This does not need a read barrier because this is called by GC.
mirror::Class* cls = root_ptr->Read<kWithoutReadBarrier>();
if (cls != nullptr && cls != weak_sentinel) {
DCHECK((cls->IsClass<kDefaultVerifyFlags>()));
// Look at the classloader of the class to know if it has been unloaded.
// This does not need a read barrier because this is called by GC.
ObjPtr<mirror::Object> class_loader =
cls->GetClassLoader<kDefaultVerifyFlags, kWithoutReadBarrier>();
if (class_loader == nullptr || visitor->IsMarked(class_loader.Ptr()) != nullptr) {
// The class loader is live, update the entry if the class has moved.
mirror::Class* new_cls = down_cast<mirror::Class*>(visitor->IsMarked(cls));
// Note that new_object can be null for CMS and newly allocated objects.
if (new_cls != nullptr && new_cls != cls) {
*root_ptr = GcRoot<mirror::Class>(new_cls);
}
} else {
// The class loader is not live, clear the entry.
*root_ptr = GcRoot<mirror::Class>(update);
}
}
}
void JitCodeCache::SweepRootTables(IsMarkedVisitor* visitor) {
MutexLock mu(Thread::Current(), lock_);
for (const auto& entry : method_code_map_) {
uint32_t number_of_roots = 0;
uint8_t* roots_data = GetRootTable(entry.first, &number_of_roots);
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 == weak_sentinel) {
// 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 {
ProcessWeakClass(
reinterpret_cast<GcRoot<mirror::Class>*>(&roots[i]), visitor, weak_sentinel);
}
}
}
// Walk over inline caches to clear entries containing unloaded classes.
for (ProfilingInfo* info : profiling_infos_) {
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) {
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);
// Notify native debugger that we are about to remove the code.
// It does nothing if we are not using native debugger.
RemoveNativeDebugInfoForJit(Thread::Current(), code_ptr);
if (OatQuickMethodHeader::FromCodePointer(code_ptr)->IsOptimized()) {
FreeData(GetRootTable(code_ptr));
} // else this is a JNI stub without any data.
uint8_t* code_allocation = reinterpret_cast<uint8_t*>(allocation);
if (HasDualCodeMapping()) {
code_allocation = TranslateAddress(code_allocation, exec_pages_, non_exec_pages_);
}
FreeCode(code_allocation);
}
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 mu(Thread::Current(), lock_);
{
MutexLock mu2(Thread::Current(), *Locks::cha_lock_);
Runtime::Current()->GetClassLinker()->GetClassHierarchyAnalysis()
->RemoveDependentsWithMethodHeaders(method_headers);
}
ScopedCodeCacheWrite scc(this);
for (const OatQuickMethodHeader* method_header : method_headers) {
FreeCodeAndData(method_header->GetCode());
}
}
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, 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.
{
ScopedCodeCacheWrite scc(this);
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));
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;
if (alloc.ContainsUnsafe(info->GetMethod())) {
info->GetMethod()->SetProfilingInfo(nullptr);
FreeData(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, lock_);
while (!IsWeakAccessEnabled(self)) {
inline_cache_cond_.Wait(self);
}
}
void JitCodeCache::BroadcastForInlineCacheAccess() {
Thread* self = Thread::Current();
MutexLock mu(self, 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,
Handle<mirror::ObjectArray<mirror::Class>> array) {
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 (size_t in_cache = 0, in_array = 0;
in_cache < InlineCache::kIndividualCacheSize;
++in_cache) {
mirror::Class* object = ic.classes_[in_cache].Read();
if (object != nullptr) {
array->Set(in_array++, 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_) {
lock_.Unlock(self);
{
ScopedThreadSuspension sts(self, kSuspended);
MutexLock mu(self, lock_);
WaitForPotentialCollectionToComplete(self);
}
lock_.Lock(self);
}
}
const MemMap* JitCodeCache::GetUpdatableCodeMapping() const {
if (HasDualCodeMapping()) {
return &non_exec_pages_;
} else if (HasCodeMapping()) {
return &exec_pages_;
} else {
return nullptr;
}
}
uint8_t* JitCodeCache::CommitCodeInternal(Thread* self,
ArtMethod* method,
uint8_t* stack_map,
uint8_t* roots_data,
const uint8_t* code,
size_t code_size,
size_t data_size,
bool osr,
const std::vector<Handle<mirror::Object>>& roots,
bool has_should_deoptimize_flag,
const ArenaSet<ArtMethod*>&
cha_single_implementation_list) {
DCHECK(!method->IsNative() || !osr);
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);
}
OatQuickMethodHeader* method_header = nullptr;
uint8_t* nox_memory = nullptr;
uint8_t* code_ptr = nullptr;
MutexLock mu(self, 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);
{
ScopedCodeCacheWrite scc(this);
size_t alignment = GetJitCodeAlignment();
// Ensure the header ends up at expected instruction alignment.
size_t header_size = RoundUp(sizeof(OatQuickMethodHeader), alignment);
size_t total_size = header_size + code_size;
// AllocateCode allocates memory in non-executable region for alignment header and code. The
// header size may include alignment padding.
nox_memory = AllocateCode(total_size);
if (nox_memory == nullptr) {
return nullptr;
}
// code_ptr points to non-executable code.
code_ptr = nox_memory + header_size;
std::copy(code, code + code_size, code_ptr);
method_header = OatQuickMethodHeader::FromCodePointer(code_ptr);
// From here code_ptr points to executable code.
if (HasDualCodeMapping()) {
code_ptr = TranslateAddress(code_ptr, non_exec_pages_, exec_pages_);
}
new (method_header) OatQuickMethodHeader(
(stack_map != nullptr) ? code_ptr - stack_map : 0u,
code_size);
DCHECK(!Runtime::Current()->IsAotCompiler());
if (has_should_deoptimize_flag) {
method_header->SetHasShouldDeoptimizeFlag();
}
// Update method_header pointer to executable code region.
if (HasDualCodeMapping()) {
method_header = TranslateAddress(method_header, non_exec_pages_, exec_pages_);
}
// Both instruction and data caches need flushing to the point of unification where both share
// a common view of memory. Flushing the data cache ensures the dirty cachelines from the
// newly added code are written out to the point of unification. Flushing the instruction
// cache ensures the newly written code will be fetched from the point of unification before
// use. Memory in the code cache is re-cycled as code is added and removed. The flushes
// prevent stale code from residing in the instruction cache.
//
// Caches are flushed before write permission is removed because some ARMv8 Qualcomm kernels
// may trigger a segfault if a page fault occurs when requesting a cache maintenance
// operation. This is a kernel bug that we need to work around until affected devices
// (e.g. Nexus 5X and 6P) stop being supported or their kernels are fixed.
//
// For reference, this behavior is caused by this commit:
// https://android.googlesource.com/kernel/msm/+/3fbe6bc28a6b9939d0650f2f17eb5216c719950c
//
bool cache_flush_success = true;
if (HasDualCodeMapping()) {
// Flush the data cache lines associated with the non-executable copy of the code just added.
cache_flush_success = FlushCpuCaches(nox_memory, nox_memory + total_size);
}
// Invalidate i-cache for the executable mapping.
if (cache_flush_success) {
uint8_t* x_memory = reinterpret_cast<uint8_t*>(FromCodeToAllocation(code_ptr));
cache_flush_success = FlushCpuCaches(x_memory, x_memory + total_size);
}
// If flushing the cache has failed, reject the allocation because we can't guarantee
// correctness of the instructions present in the processor caches.
if (!cache_flush_success) {
PLOG(ERROR) << "Cache flush failed for JIT code, code not committed.";
FreeCode(nox_memory);
return nullptr;
}
// Ensure CPU instruction pipelines are flushed for all cores. This is necessary for
// correctness as code may still be in instruction pipelines despite the i-cache flush. It is
// not safe to assume that changing permissions with mprotect (RX->RWX->RX) will cause a TLB
// shootdown (incidentally invalidating the CPU pipelines by sending an IPI to all cores to
// notify them of the TLB invalidation). Some architectures, notably ARM and ARM64, have
// hardware support that broadcasts TLB invalidations and so their kernels have no software
// based TLB shootdown. The sync-core flavor of membarrier was introduced in Linux 4.16 to
// address this (see mbarrier(2)). The membarrier here will fail on prior kernels and on
// platforms lacking the appropriate support.
art::membarrier(art::MembarrierCommand::kPrivateExpeditedSyncCore);
number_of_compilations_++;
}
// 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 (!single_impl_still_valid) {
VLOG(jit) << "JIT discarded jitted code due to invalid single-implementation assumptions.";
return nullptr;
}
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);
instrumentation::Instrumentation* instrum = Runtime::Current()->GetInstrumentation();
for (ArtMethod* m : data->GetMethods()) {
if (!class_linker->IsQuickResolutionStub(m->GetEntryPointFromQuickCompiledCode())) {
instrum->UpdateMethodsCode(m, method_header->GetEntryPoint());
}
}
} else {
// Fill the root table before updating the entry point.
DCHECK_EQ(FromStackMapToRoots(stack_map), roots_data);
DCHECK_LE(roots_data, stack_map);
FillRootTable(roots_data, roots);
{
// Flush data cache, as compiled code references literals in it.
// TODO(oth): establish whether this is necessary.
if (!FlushCpuCaches(roots_data, roots_data + data_size)) {
PLOG(ERROR) << "Cache flush failed for JIT data, code not committed.";
ScopedCodeCacheWrite scc(this);
FreeCode(nox_memory);
return nullptr;
}
}
method_code_map_.Put(code_ptr, method);
if (osr) {
number_of_osr_compilations_++;
osr_code_map_.Put(method, code_ptr);
} else if (class_linker->IsQuickResolutionStub(
method->GetEntryPointFromQuickCompiledCode())) {
// This situation currently only occurs in the jit-zygote mode.
DCHECK(Runtime::Current()->IsZygote());
DCHECK(Runtime::Current()->IsUsingApexBootImageLocation());
DCHECK(method->GetProfilingInfo(kRuntimePointerSize) != nullptr);
DCHECK(method->GetDeclaringClass()->GetClassLoader() == nullptr);
// Save the entrypoint, so it can be fethed later once the class is
// initialized.
method->GetProfilingInfo(kRuntimePointerSize)->SetSavedEntryPoint(
method_header->GetEntryPoint());
} else {
Runtime::Current()->GetInstrumentation()->UpdateMethodsCode(
method, method_header->GetEntryPoint());
}
}
VLOG(jit)
<< "JIT added (osr=" << std::boolalpha << osr << std::noboolalpha << ") "
<< 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());
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);
}
}
return reinterpret_cast<uint8_t*>(method_header);
}
size_t JitCodeCache::CodeCacheSize() {
MutexLock mu(Thread::Current(), 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(), 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())) {
ProfilingInfo* info = method->GetProfilingInfo(kRuntimePointerSize);
if (info != nullptr) {
RemoveElement(profiling_infos_, info);
}
method->SetProfilingInfo(nullptr);
}
bool in_cache = false;
ScopedCodeCacheWrite ccw(this);
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);
}
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(), 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(), 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 ProfilingInfo to the new one and remove it from the old_method.
if (old_method->GetProfilingInfo(kRuntimePointerSize) != nullptr) {
DCHECK_EQ(old_method->GetProfilingInfo(kRuntimePointerSize)->GetMethod(), old_method);
ProfilingInfo* info = old_method->GetProfilingInfo(kRuntimePointerSize);
old_method->SetProfilingInfo(nullptr);
// Since the JIT should be paused and all threads suspended by the time this is called these
// checks should always pass.
DCHECK(!info->IsInUseByCompiler());
new_method->SetProfilingInfo(info);
// Get rid of the old saved entrypoint if it is there.
info->SetSavedEntryPoint(nullptr);
info->method_ = new_method;
}
// 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::ClearEntryPointsInZygoteExecSpace() {
MutexLock mu(Thread::Current(), lock_);
// Iterate over profiling infos to know which methods may have been JITted. Note that
// to be JITted, a method must have a profiling info.
for (ProfilingInfo* info : profiling_infos_) {
ArtMethod* method = info->GetMethod();
if (IsInZygoteExecSpace(method->GetEntryPointFromQuickCompiledCode())) {
method->SetEntryPointFromQuickCompiledCode(GetQuickToInterpreterBridge());
}
// If zygote does method tracing, or in some configuration where
// the JIT zygote does GC, we also need to clear the saved entry point
// in the profiling info.
if (IsInZygoteExecSpace(info->GetSavedEntryPoint())) {
info->SetSavedEntryPoint(nullptr);
}
}
}
size_t JitCodeCache::CodeCacheSizeLocked() {
return used_memory_for_code_;
}
size_t JitCodeCache::DataCacheSize() {
MutexLock mu(Thread::Current(), lock_);
return DataCacheSizeLocked();
}
size_t JitCodeCache::DataCacheSizeLocked() {
return used_memory_for_data_;
}
void JitCodeCache::ClearData(Thread* self,
uint8_t* stack_map_data,
uint8_t* roots_data) {
DCHECK_EQ(FromStackMapToRoots(stack_map_data), roots_data);
MutexLock mu(self, lock_);
FreeData(reinterpret_cast<uint8_t*>(roots_data));
}
size_t JitCodeCache::ReserveData(Thread* self,
size_t stack_map_size,
size_t number_of_roots,
ArtMethod* method,
uint8_t** stack_map_data,
uint8_t** roots_data) {
size_t table_size = ComputeRootTableSize(number_of_roots);
size_t size = RoundUp(stack_map_size + table_size, sizeof(void*));
uint8_t* result = nullptr;
{
ScopedThreadSuspension sts(self, kSuspended);
MutexLock mu(self, lock_);
WaitForPotentialCollectionToComplete(self);
result = AllocateData(size);
}
if (result == nullptr) {
// Retry.
GarbageCollectCache(self);
ScopedThreadSuspension sts(self, kSuspended);
MutexLock mu(self, lock_);
WaitForPotentialCollectionToComplete(self);
result = AllocateData(size);
}
MutexLock mu(self, lock_);
histogram_stack_map_memory_use_.AddValue(size);
if (size > kStackMapSizeLogThreshold) {
LOG(INFO) << "JIT allocated "
<< PrettySize(size)
<< " for stack maps of "
<< ArtMethod::PrettyMethod(method);
}
if (result != nullptr) {
*roots_data = result;
*stack_map_data = result + table_size;
FillRootTableLength(*roots_data, number_of_roots);
return size;
} else {
*roots_data = nullptr;
*stack_map_data = nullptr;
return 0;
}
}
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 sanity check this below.
for (const instrumentation::InstrumentationStackFrame& frame
: *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(frame.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::SetFootprintLimit(size_t new_footprint) {
size_t data_space_footprint = new_footprint / kCodeAndDataCapacityDivider;
DCHECK(IsAlignedParam(data_space_footprint, kPageSize));
DCHECK_EQ(data_space_footprint * kCodeAndDataCapacityDivider, new_footprint);
mspace_set_footprint_limit(data_mspace_, data_space_footprint);
if (HasCodeMapping()) {
ScopedCodeCacheWrite scc(this);
mspace_set_footprint_limit(exec_mspace_, new_footprint - data_space_footprint);
}
}
bool JitCodeCache::IncreaseCodeCacheCapacity() {
if (current_capacity_ == max_capacity_) {
return false;
}
// Double the capacity if we're below 1MB, or increase it by 1MB if
// we're above.
if (current_capacity_ < 1 * MB) {
current_capacity_ *= 2;
} else {
current_capacity_ += 1 * MB;
}
if (current_capacity_ > max_capacity_) {
current_capacity_ = max_capacity_;
}
VLOG(jit) << "Increasing code cache capacity to " << PrettySize(current_capacity_);
SetFootprintLimit(current_capacity_);
return true;
}
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::ShouldDoFullCollection() {
if (current_capacity_ == max_capacity_) {
// Always do a full collection when the code cache is full.
return true;
} else if (current_capacity_ < 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, lock_);
if (!garbage_collect_code_) {
IncreaseCodeCacheCapacity();
return;
} else if (WaitForPotentialCollectionToComplete(self)) {
return;
} else {
number_of_collections_++;
live_bitmap_.reset(CodeCacheBitmap::Create(
"code-cache-bitmap",
reinterpret_cast<uintptr_t>(exec_pages_.Begin()),
reinterpret_cast<uintptr_t>(exec_pages_.Begin() + current_capacity_ / 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, 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, 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;
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) {
// Save the entry point of methods we have compiled, and update the entry
// point of those methods to the interpreter. If the method is invoked, the
// interpreter will update its entry point to the compiled code and call it.
for (ProfilingInfo* info : profiling_infos_) {
const void* entry_point = info->GetMethod()->GetEntryPointFromQuickCompiledCode();
if (!IsInZygoteDataSpace(info) && ContainsPc(entry_point)) {
info->SetSavedEntryPoint(entry_point);
// Don't call Instrumentation::UpdateMethodsCode(), as it can check the declaring
// class of the method. We may be concurrently running a GC which makes accessing
// the class unsafe. We know it is OK to bypass the instrumentation as we've just
// checked that the current entry point is JIT compiled code.
info->GetMethod()->SetEntryPointFromQuickCompiledCode(GetQuickToInterpreterBridge());
}
}
DCHECK(CheckLiveCompiledCodeHasProfilingInfo());
// 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, lock_);
ScopedCodeCacheWrite scc(this);
// 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()));
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);
it = method_code_map_.erase(it);
}
}
}
FreeAllMethodHeaders(method_headers);
}
bool JitCodeCache::GetGarbageCollectCode() {
MutexLock mu(Thread::Current(), lock_);
return garbage_collect_code_;
}
void JitCodeCache::SetGarbageCollectCode(bool value) {
Thread* self = Thread::Current();
MutexLock mu(self, lock_);
if (garbage_collect_code_ != value) {
if (garbage_collect_code_) {
// When dynamically disabling the garbage collection, we neee
// to make sure that a potential current collection is finished, and also
// clear the saved entry point in profiling infos to avoid dangling pointers.
WaitForPotentialCollectionToComplete(self);
for (ProfilingInfo* info : profiling_infos_) {
info->SetSavedEntryPoint(nullptr);
}
}
// Update the flag while holding the lock to ensure no thread will try to GC.
garbage_collect_code_ = value;
}
}
void JitCodeCache::DoCollection(Thread* self, bool collect_profiling_info) {
ScopedTrace trace(__FUNCTION__);
{
MutexLock mu(self, lock_);
if (collect_profiling_info) {
// Clear the profiling info of methods that do not have compiled code as entrypoint.
// Also remove the saved entry point from the ProfilingInfo objects.
for (ProfilingInfo* info : profiling_infos_) {
const void* ptr = info->GetMethod()->GetEntryPointFromQuickCompiledCode();
if (!ContainsPc(ptr) && !info->IsInUseByCompiler() && !IsInZygoteDataSpace(info)) {
info->GetMethod()->SetProfilingInfo(nullptr);
}
if (info->GetSavedEntryPoint() != nullptr) {
info->SetSavedEntryPoint(nullptr);
// We are going to move this method back to interpreter. Clear the counter now to
// give it a chance to be hot again.
ClearMethodCounter(info->GetMethod(), /*was_warm=*/ true);
}
}
} else if (kIsDebugBuild) {
// Sanity check that the profiling infos do not have a dangling entry point.
for (ProfilingInfo* info : profiling_infos_) {
DCHECK(!Runtime::Current()->IsZygote());
const void* entry_point = info->GetSavedEntryPoint();
DCHECK(entry_point == nullptr || IsInZygoteExecSpace(entry_point));
}
}
// 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) {
MutexLock mu(self, lock_);
// Free all profiling infos of methods not compiled nor being compiled.
auto profiling_kept_end = std::remove_if(profiling_infos_.begin(), profiling_infos_.end(),
[this] (ProfilingInfo* info) NO_THREAD_SAFETY_ANALYSIS {
const void* ptr = info->GetMethod()->GetEntryPointFromQuickCompiledCode();
// We have previously cleared the ProfilingInfo pointer in the ArtMethod in the hope
// that the compiled code would not get revived. As mutator threads run concurrently,
// they may have revived the compiled code, and now we are in the situation where
// a method has compiled code but no ProfilingInfo.
// We make sure compiled methods have a ProfilingInfo object. It is needed for
// code cache collection.
if (ContainsPc(ptr) &&
info->GetMethod()->GetProfilingInfo(kRuntimePointerSize) == nullptr) {
info->GetMethod()->SetProfilingInfo(info);
} else if (info->GetMethod()->GetProfilingInfo(kRuntimePointerSize) != info) {
// No need for this ProfilingInfo object anymore.
FreeData(reinterpret_cast<uint8_t*>(info));
return true;
}
return false;
});
profiling_infos_.erase(profiling_kept_end, profiling_infos_.end());
DCHECK(CheckLiveCompiledCodeHasProfilingInfo());
}
}
bool JitCodeCache::CheckLiveCompiledCodeHasProfilingInfo() {
ScopedTrace trace(__FUNCTION__);
// Check that methods we have compiled do have a ProfilingInfo object. We would
// have memory leaks of compiled code otherwise.
for (const auto& it : method_code_map_) {
ArtMethod* method = it.second;
if (method->GetProfilingInfo(kRuntimePointerSize) == nullptr) {
const void* code_ptr = it.first;
const OatQuickMethodHeader* method_header = OatQuickMethodHeader::FromCodePointer(code_ptr);
if (method_header->GetEntryPoint() == method->GetEntryPointFromQuickCompiledCode()) {
// If the code is not dead, then we have a problem. Note that this can even
// happen just after a collection, as mutator threads are running in parallel
// and could deoptimize an existing compiled code.
return false;
}
}
}
return true;
}
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(), 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 {
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()) {
// When we are walking the stack to redefine classes and creating obsolete methods it is
// possible that we might have updated the method_code_map by making this method obsolete in a
// previous frame. Therefore we should just check that the non-obsolete version of this method
// is the one we expect. We change to the non-obsolete versions in the error message since the
// obsolete version of the method might not be fully initialized yet. This situation can only
// occur when we are in the process of allocating and setting up obsolete methods. Otherwise
// method and it->second should be identical. (See openjdkjvmti/ti_redefine.cc for more
// information.)
DCHECK_EQ(found_method->GetNonObsoleteMethod(), method->GetNonObsoleteMethod())
<< ArtMethod::PrettyMethod(method->GetNonObsoleteMethod()) << " "
<< ArtMethod::PrettyMethod(found_method->GetNonObsoleteMethod()) << " "
<< std::hex << pc;
}
return method_header;
}
OatQuickMethodHeader* JitCodeCache::LookupOsrMethodHeader(ArtMethod* method) {
MutexLock mu(Thread::Current(), 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,
bool retry_allocation)
// No thread safety analysis as we are using TryLock/Unlock explicitly.
NO_THREAD_SAFETY_ANALYSIS {
ProfilingInfo* info = nullptr;
if (!retry_allocation) {
// If we are allocating for the interpreter, just try to lock, to avoid
// lock contention with the JIT.
if (lock_.ExclusiveTryLock(self)) {
info = AddProfilingInfoInternal(self, method, entries);
lock_.ExclusiveUnlock(self);
}
} else {
{
MutexLock mu(self, lock_);
info = AddProfilingInfoInternal(self, method, entries);
}
if (info == nullptr) {
GarbageCollectCache(self);
MutexLock mu(self, lock_);
info = AddProfilingInfoInternal(self, method, entries);
}
}
return info;
}
ProfilingInfo* JitCodeCache::AddProfilingInfoInternal(Thread* self ATTRIBUTE_UNUSED,
ArtMethod* method,
const std::vector<uint32_t>& entries) {
size_t profile_info_size = RoundUp(
sizeof(ProfilingInfo) + sizeof(InlineCache) * entries.size(),
sizeof(void*));
// Check whether some other thread has concurrently created it.
ProfilingInfo* info = method->GetProfilingInfo(kRuntimePointerSize);
if (info != nullptr) {
return info;
}
uint8_t* data = AllocateData(profile_info_size);
if (data == nullptr) {
return nullptr;
}
info = new (data) ProfilingInfo(method, entries);
// Make sure other threads see the data in the profiling info object before the
// store in the ArtMethod's ProfilingInfo pointer.
std::atomic_thread_fence(std::memory_order_release);
method->SetProfilingInfo(info);
profiling_infos_.push_back(info);
histogram_profiling_info_memory_use_.AddValue(profile_info_size);
return info;
}
// NO_THREAD_SAFETY_ANALYSIS as this is called from mspace code, at which point the lock
// is already held.
void* JitCodeCache::MoreCore(const void* mspace, intptr_t increment) NO_THREAD_SAFETY_ANALYSIS {
if (mspace == exec_mspace_) {
DCHECK(exec_mspace_ != nullptr);
const MemMap* const code_pages = GetUpdatableCodeMapping();
void* result = code_pages->Begin() + exec_end_;
exec_end_ += increment;
return result;
} else {
DCHECK_EQ(data_mspace_, mspace);
void* result = data_pages_.Begin() + data_end_;
data_end_ += increment;
return result;
}
}
void JitCodeCache::GetProfiledMethods(const std::set<std::string>& dex_base_locations,
std::vector<ProfileMethodInfo>& methods) {
Thread* self = Thread::Current();
WaitUntilInlineCacheAccessible(self);
MutexLock mu(self, lock_);
ScopedTrace trace(__FUNCTION__);
uint16_t jit_compile_threshold = Runtime::Current()->GetJITOptions()->GetCompileThreshold();
for (const ProfilingInfo* info : profiling_infos_) {
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(), lock_);
return osr_code_map_.find(method) != osr_code_map_.end();
}
bool JitCodeCache::NotifyCompilationOf(ArtMethod* method, Thread* self, bool osr) {
if (!osr && ContainsPc(method->GetEntryPointFromQuickCompiledCode())) {
return false;
}
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
if (class_linker->IsQuickResolutionStub(method->GetEntryPointFromQuickCompiledCode())) {
if (!Runtime::Current()->IsUsingApexBootImageLocation() || !Runtime::Current()->IsZygote()) {
// Unless we're running as zygote in the jitzygote experiment, we currently don't save
// the JIT compiled code if we cannot update the entrypoint due to having the resolution stub.
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;
}
}
MutexLock mu(self, lock_);
if (osr && (osr_code_map_.find(method) != osr_code_map_.end())) {
return false;
}
if (UNLIKELY(method->IsNative())) {
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.
instrumentation::Instrumentation* instrumentation = Runtime::Current()->GetInstrumentation();
for (ArtMethod* m : data->GetMethods()) {
// Call the dedicated method instead of the more generic UpdateMethodsCode, because
// `m` might be in the process of being deleted.
if (!class_linker->IsQuickResolutionStub(m->GetEntryPointFromQuickCompiledCode())) {
instrumentation->UpdateNativeMethodsCodeToJitCode(m, entrypoint);
}
}
if (collection_in_progress_) {
if (!IsInZygoteExecSpace(data->GetCode())) {
GetLiveBitmap()->AtomicTestAndSet(FromCodeToAllocation(data->GetCode()));
}
}
}
return new_compilation;
} else {
ProfilingInfo* info = method->GetProfilingInfo(kRuntimePointerSize);
if (info == nullptr) {
VLOG(jit) << method->PrettyMethod() << " needs a ProfilingInfo to be compiled";
// Because the counter is not atomic, there are some rare cases where we may not hit the
// threshold for creating the ProfilingInfo. Reset the counter now to "correct" this.
ClearMethodCounter(method, /*was_warm=*/ false);
return false;
}
if (info->IsMethodBeingCompiled(osr)) {
return false;
}
info->SetIsMethodBeingCompiled(true, osr);
return true;
}
}
ProfilingInfo* JitCodeCache::NotifyCompilerUse(ArtMethod* method, Thread* self) {
MutexLock mu(self, lock_);
ProfilingInfo* info = method->GetProfilingInfo(kRuntimePointerSize);
if (info != nullptr) {
if (!info->IncrementInlineUse()) {
// Overflow of inlining uses, just bail.
return nullptr;
}
}
return info;
}
void JitCodeCache::DoneCompilerUse(ArtMethod* method, Thread* self) {
MutexLock mu(self, lock_);
ProfilingInfo* info = method->GetProfilingInfo(kRuntimePointerSize);
DCHECK(info != nullptr);
info->DecrementInlineUse();
}
void JitCodeCache::DoneCompiling(ArtMethod* method, Thread* self, bool osr) {
DCHECK_EQ(Thread::Current(), self);
MutexLock mu(self, 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 CommitCodeInternal() updated entrypoints of all methods in the JniStubData.
} else {
ProfilingInfo* info = method->GetProfilingInfo(kRuntimePointerSize);
DCHECK(info->IsMethodBeingCompiled(osr));
info->SetIsMethodBeingCompiled(false, osr);
}
}
void JitCodeCache::InvalidateCompiledCodeFor(ArtMethod* method,
const OatQuickMethodHeader* header) {
DCHECK(!method->IsNative());
ProfilingInfo* profiling_info = method->GetProfilingInfo(kRuntimePointerSize);
const void* method_entrypoint = method->GetEntryPointFromQuickCompiledCode();
if ((profiling_info != nullptr) &&
(profiling_info->GetSavedEntryPoint() == header->GetEntryPoint())) {
// When instrumentation is set, the actual entrypoint is the one in the profiling info.
method_entrypoint = profiling_info->GetSavedEntryPoint();
// Prevent future uses of the compiled code.
profiling_info->SetSavedEntryPoint(nullptr);
}
// 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=*/ profiling_info != nullptr);
} else {
MutexLock mu(Thread::Current(), 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);
}
}
}
uint8_t* JitCodeCache::AllocateCode(size_t allocation_size) {
// Each allocation should be on its own set of cache lines. The allocation must be large enough
// for header, code, and any padding.
size_t alignment = GetJitCodeAlignment();
uint8_t* result = reinterpret_cast<uint8_t*>(
mspace_memalign(exec_mspace_, alignment, allocation_size));
size_t header_size = RoundUp(sizeof(OatQuickMethodHeader), alignment);
// Ensure the header ends up at expected instruction alignment.
DCHECK_ALIGNED_PARAM(reinterpret_cast<uintptr_t>(result + header_size), alignment);
used_memory_for_code_ += mspace_usable_size(result);
return result;
}
void JitCodeCache::FreeCode(uint8_t* code) {
if (IsInZygoteExecSpace(code)) {
// No need to free, this is shared memory.
return;
}
used_memory_for_code_ -= mspace_usable_size(code);
mspace_free(exec_mspace_, code);
}
uint8_t* JitCodeCache::AllocateData(size_t data_size) {
void* result = mspace_malloc(data_mspace_, data_size);
used_memory_for_data_ += mspace_usable_size(result);
return reinterpret_cast<uint8_t*>(result);
}
void JitCodeCache::FreeData(uint8_t* data) {
if (IsInZygoteDataSpace(data)) {
// No need to free, this is shared memory.
return;
}
used_memory_for_data_ -= mspace_usable_size(data);
mspace_free(data_mspace_, data);
}
void JitCodeCache::Dump(std::ostream& os) {
MutexLock mu(Thread::Current(), lock_);
os << "Current JIT code cache size: " << PrettySize(used_memory_for_code_) << "\n"
<< "Current JIT data cache size: " << PrettySize(used_memory_for_data_) << "\n"
<< "Current JIT mini-debug-info size: " << PrettySize(GetJitMiniDebugInfoMemUsage()) << "\n"
<< "Current JIT capacity: " << PrettySize(current_capacity_) << "\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 compilations: " << number_of_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) {
if (is_zygote) {
// Don't transition if this is for a child zygote.
return;
}
MutexLock mu(Thread::Current(), lock_);
zygote_data_pages_ = std::move(data_pages_);
zygote_exec_pages_ = std::move(exec_pages_);
zygote_data_mspace_ = data_mspace_;
zygote_exec_mspace_ = exec_mspace_;
size_t initial_capacity = Runtime::Current()->GetJITOptions()->GetCodeCacheInitialCapacity();
size_t max_capacity = Runtime::Current()->GetJITOptions()->GetCodeCacheMaxCapacity();
InitializeState(initial_capacity, max_capacity);
std::string error_msg;
if (!InitializeMappings(/* rwx_memory_allowed= */ !is_system_server, is_zygote, &error_msg)) {
LOG(WARNING) << "Could not reset JIT state after zygote fork: " << error_msg;
return;
}
InitializeSpaces();
}
} // namespace jit
} // namespace art