Basic obsolete methods support
Add support for executing obsolete methods following redefinitions.
This support includes methods that have been jitted. This does not add
any additional validity checks to our redefinition functions.
Note using work-arounds to ensure 916 works pending some fixes to the
compiler, deoptimizer, or both.
Test: ./test/run-test --host 914
Test: ./test/run-test --host 915
Test: ./test/run-test --host 916
Test: mma -j40 test-art-host
Test: ART_TEST_JIT=true \
ART_TEST_INTERPRETER=true mma -j40 test-art-host
Test: ./art/tools/run-jdwp-tests.sh --mode=host --variant=X64
Test: ./art/tools/run-jdwp-tests.sh --mode=host --variant=X64 --no-jit
Bug: 32369913
Bug: 33630159
Change-Id: I78ef95f484146f1fb93c37fc50f56575bdab2432
diff --git a/runtime/openjdkjvmti/ti_redefine.cc b/runtime/openjdkjvmti/ti_redefine.cc
index d0349b9..429409a 100644
--- a/runtime/openjdkjvmti/ti_redefine.cc
+++ b/runtime/openjdkjvmti/ti_redefine.cc
@@ -38,6 +38,8 @@
#include "events-inl.h"
#include "gc/allocation_listener.h"
#include "instrumentation.h"
+#include "jit/jit.h"
+#include "jit/jit_code_cache.h"
#include "jni_env_ext-inl.h"
#include "jvmti_allocator.h"
#include "mirror/class.h"
@@ -49,6 +51,142 @@
namespace openjdkjvmti {
+// This visitor walks thread stacks and allocates and sets up the obsolete methods. It also does
+// some basic sanity checks that the obsolete method is sane.
+class ObsoleteMethodStackVisitor : public art::StackVisitor {
+ protected:
+ ObsoleteMethodStackVisitor(
+ art::Thread* thread,
+ art::LinearAlloc* allocator,
+ const std::unordered_set<art::ArtMethod*>& obsoleted_methods,
+ /*out*/std::unordered_map<art::ArtMethod*, art::ArtMethod*>* obsolete_maps,
+ /*out*/bool* success,
+ /*out*/std::string* error_msg)
+ : StackVisitor(thread,
+ /*context*/nullptr,
+ StackVisitor::StackWalkKind::kIncludeInlinedFrames),
+ allocator_(allocator),
+ obsoleted_methods_(obsoleted_methods),
+ obsolete_maps_(obsolete_maps),
+ success_(success),
+ is_runtime_frame_(false),
+ error_msg_(error_msg) {}
+
+ ~ObsoleteMethodStackVisitor() OVERRIDE {}
+
+ public:
+ // Returns true if we successfully installed obsolete methods on this thread, filling
+ // obsolete_maps_ with the translations if needed. Returns false and fills error_msg_ if we fail.
+ // The stack is cleaned up when we fail.
+ static bool UpdateObsoleteFrames(
+ art::Thread* thread,
+ art::LinearAlloc* allocator,
+ const std::unordered_set<art::ArtMethod*>& obsoleted_methods,
+ /*out*/std::unordered_map<art::ArtMethod*, art::ArtMethod*>* obsolete_maps,
+ /*out*/std::string* error_msg) REQUIRES(art::Locks::mutator_lock_) {
+ bool success = true;
+ ObsoleteMethodStackVisitor visitor(thread,
+ allocator,
+ obsoleted_methods,
+ obsolete_maps,
+ &success,
+ error_msg);
+ visitor.WalkStack();
+ if (!success) {
+ RestoreFrames(thread, *obsolete_maps);
+ return false;
+ } else {
+ return true;
+ }
+ }
+
+ static void RestoreFrames(
+ art::Thread* thread ATTRIBUTE_UNUSED,
+ const std::unordered_map<art::ArtMethod*, art::ArtMethod*>& obsolete_maps ATTRIBUTE_UNUSED)
+ REQUIRES(art::Locks::mutator_lock_) {
+ LOG(FATAL) << "Restoring stack frames is not yet supported.";
+ }
+
+ bool VisitFrame() OVERRIDE REQUIRES(art::Locks::mutator_lock_) {
+ art::ArtMethod* old_method = GetMethod();
+ // TODO REMOVE once either current_method doesn't stick around through suspend points or deopt
+ // works through runtime methods.
+ bool prev_was_runtime_frame_ = is_runtime_frame_;
+ is_runtime_frame_ = old_method->IsRuntimeMethod();
+ if (obsoleted_methods_.find(old_method) != obsoleted_methods_.end()) {
+ // This works since when we deoptimize we set shadow frames for all frames until a
+ // native/runtime transition and for those set the return PC to a function that will complete
+ // the deoptimization. This does leave us with the unfortunate side-effect that frames just
+ // below runtime frames cannot be deoptimized at the moment.
+ // TODO REMOVE once either current_method doesn't stick around through suspend points or deopt
+ // works through runtime methods.
+ // TODO b/33616143
+ if (!IsShadowFrame() && prev_was_runtime_frame_) {
+ *error_msg_ = art::StringPrintf("Deoptimization failed due to runtime method in stack.");
+ *success_ = false;
+ return false;
+ }
+ // We cannot ensure that the right dex file is used in inlined frames so we don't support
+ // redefining them.
+ DCHECK(!IsInInlinedFrame()) << "Inlined frames are not supported when using redefinition";
+ // TODO We should really support intrinsic obsolete methods.
+ // TODO We should really support redefining intrinsics.
+ // We don't support intrinsics so check for them here.
+ DCHECK(!old_method->IsIntrinsic());
+ art::ArtMethod* new_obsolete_method = nullptr;
+ auto obsolete_method_pair = obsolete_maps_->find(old_method);
+ if (obsolete_method_pair == obsolete_maps_->end()) {
+ // Create a new Obsolete Method and put it in the list.
+ art::Runtime* runtime = art::Runtime::Current();
+ art::ClassLinker* cl = runtime->GetClassLinker();
+ auto ptr_size = cl->GetImagePointerSize();
+ const size_t method_size = art::ArtMethod::Size(ptr_size);
+ auto* method_storage = allocator_->Alloc(GetThread(), method_size);
+ if (method_storage == nullptr) {
+ *success_ = false;
+ *error_msg_ = art::StringPrintf("Unable to allocate storage for obsolete version of '%s'",
+ old_method->PrettyMethod().c_str());
+ return false;
+ }
+ new_obsolete_method = new (method_storage) art::ArtMethod();
+ new_obsolete_method->CopyFrom(old_method, ptr_size);
+ new_obsolete_method->SetIsObsolete();
+ obsolete_maps_->insert({old_method, new_obsolete_method});
+ // Update JIT Data structures to point to the new method.
+ art::jit::Jit* jit = art::Runtime::Current()->GetJit();
+ if (jit != nullptr && jit->GetCodeCache()->ContainsMethod(old_method)) {
+ // Notify the JIT we are making this obsolete method. It will update it's maps and change
+ // entrypoint etc over.
+ jit->GetCodeCache()->MoveObsoleteMethod(old_method, new_obsolete_method);
+ }
+ DCHECK_EQ(new_obsolete_method->GetDeclaringClass(), old_method->GetDeclaringClass());
+ } else {
+ new_obsolete_method = obsolete_method_pair->second;
+ }
+ DCHECK(new_obsolete_method != nullptr);
+ SetMethod(new_obsolete_method);
+ }
+ *success_ = true;
+ return true;
+ }
+
+ private:
+ // The linear allocator we should use to make new methods.
+ art::LinearAlloc* allocator_;
+ // The set of all methods which could be obsoleted.
+ const std::unordered_set<art::ArtMethod*>& obsoleted_methods_;
+ // A map from the original to the newly allocated obsolete method for frames on this thread. The
+ // values in this map must be added to the obsolete_methods_ (and obsolete_dex_caches_) fields of
+ // the redefined classes ClassExt by the caller.
+ std::unordered_map<art::ArtMethod*, art::ArtMethod*>* obsolete_maps_;
+ bool* success_;
+ // TODO REMOVE once either current_method doesn't stick around through suspend points or deopt
+ // works through runtime methods.
+ bool is_runtime_frame_;
+ std::string* error_msg_;
+};
+
+
// Moves dex data to an anonymous, read-only mmap'd region.
std::unique_ptr<art::MemMap> Redefiner::MoveDataToMemMap(const std::string& original_location,
jint data_len,
@@ -72,6 +210,8 @@
return map;
}
+// TODO This should handle doing multiple classes at once so we need to do less cleanup when things
+// go wrong.
jvmtiError Redefiner::RedefineClass(ArtJvmTiEnv* env,
art::Runtime* runtime,
art::Thread* self,
@@ -112,6 +252,8 @@
*error_msg = os.str();
return ERR(INVALID_CLASS_FORMAT);
}
+ // Stop JIT for the duration of this redefine.
+ art::jit::ScopedJitSuspend suspend_jit;
// Get shared mutator lock.
art::ScopedObjectAccess soa(self);
art::StackHandleScope<1> hs(self);
@@ -292,6 +434,109 @@
return true;
}
+struct CallbackCtx {
+ Redefiner* const r;
+ art::LinearAlloc* allocator;
+ std::unordered_map<art::ArtMethod*, art::ArtMethod*> obsolete_map;
+ std::unordered_set<art::ArtMethod*> obsolete_methods;
+ bool success;
+ std::string* error_msg;
+
+ CallbackCtx(Redefiner* self, art::LinearAlloc* alloc, std::string* error)
+ : r(self), allocator(alloc), success(true), error_msg(error) {}
+};
+
+void DoRestoreObsoleteMethodsCallback(art::Thread* t, void* vdata) NO_THREAD_SAFETY_ANALYSIS {
+ CallbackCtx* data = reinterpret_cast<CallbackCtx*>(vdata);
+ ObsoleteMethodStackVisitor::RestoreFrames(t, data->obsolete_map);
+}
+
+void DoAllocateObsoleteMethodsCallback(art::Thread* t, void* vdata) NO_THREAD_SAFETY_ANALYSIS {
+ CallbackCtx* data = reinterpret_cast<CallbackCtx*>(vdata);
+ if (data->success) {
+ // Don't do anything if we already failed once.
+ data->success = ObsoleteMethodStackVisitor::UpdateObsoleteFrames(t,
+ data->allocator,
+ data->obsolete_methods,
+ &data->obsolete_map,
+ data->error_msg);
+ }
+}
+
+void Redefiner::AddAllDeclaredMethods(
+ art::mirror::Class* art_klass,
+ art::PointerSize ptr_size,
+ /*out*/std::unordered_set<art::ArtMethod*>* declared_methods) {
+ for (auto& m : art_klass->GetDeclaredMethods(ptr_size)) {
+ declared_methods->insert(&m);
+ }
+}
+
+bool Redefiner::AllocateObsoleteMethods(art::mirror::Class* art_klass) {
+ art::ScopedAssertNoThreadSuspension ns("No thread suspension during thread stack walking");
+ art::mirror::ClassExt* ext = art_klass->GetExtData();
+ CHECK(ext->GetObsoleteMethods() != nullptr);
+ CallbackCtx ctx(this, art_klass->GetClassLoader()->GetAllocator(), error_msg_);
+ AddAllDeclaredMethods(art_klass, art::kRuntimePointerSize, &ctx.obsolete_methods);
+ for (art::ArtMethod* old_method : ctx.obsolete_methods) {
+ if (old_method->IsIntrinsic()) {
+ *error_msg_ = art::StringPrintf("Method '%s' is intrinsic and cannot be made obsolete!",
+ old_method->PrettyMethod().c_str());
+ return false;
+ }
+ }
+ {
+ art::MutexLock mu(self_, *art::Locks::thread_list_lock_);
+ art::ThreadList* list = art::Runtime::Current()->GetThreadList();
+ list->ForEach(DoAllocateObsoleteMethodsCallback, static_cast<void*>(&ctx));
+ if (!ctx.success) {
+ list->ForEach(DoRestoreObsoleteMethodsCallback, static_cast<void*>(&ctx));
+ return false;
+ }
+ }
+ FillObsoleteMethodMap(art_klass, ctx.obsolete_map);
+ return true;
+}
+
+void Redefiner::FillObsoleteMethodMap(
+ art::mirror::Class* art_klass,
+ const std::unordered_map<art::ArtMethod*, art::ArtMethod*>& obsoletes) {
+ int32_t index = 0;
+ art::mirror::ClassExt* ext_data = art_klass->GetExtData();
+ art::mirror::PointerArray* obsolete_methods = ext_data->GetObsoleteMethods();
+ art::mirror::ObjectArray<art::mirror::DexCache>* obsolete_dex_caches =
+ ext_data->GetObsoleteDexCaches();
+ int32_t num_method_slots = obsolete_methods->GetLength();
+ // Find the first empty index.
+ for (; index < num_method_slots; index++) {
+ if (obsolete_methods->GetElementPtrSize<art::ArtMethod*>(
+ index, art::kRuntimePointerSize) == nullptr) {
+ break;
+ }
+ }
+ // Make sure we have enough space.
+ CHECK_GT(num_method_slots, static_cast<int32_t>(obsoletes.size() + index));
+ CHECK(obsolete_dex_caches->Get(index) == nullptr);
+ // Fill in the map.
+ for (auto& obs : obsoletes) {
+ obsolete_methods->SetElementPtrSize(index, obs.second, art::kRuntimePointerSize);
+ obsolete_dex_caches->Set(index, art_klass->GetDexCache());
+ index++;
+ }
+}
+
+// TODO It should be possible to only deoptimize the specific obsolete methods.
+// TODO ReJitEverything can (sort of) fail. In certain cases it will skip deoptimizing some frames.
+// If one of these frames is an obsolete method we have a problem. b/33616143
+// TODO This shouldn't be necessary once we can ensure that the current method is not kept in
+// registers across suspend points.
+// TODO Pending b/33630159
+void Redefiner::EnsureObsoleteMethodsAreDeoptimized() {
+ art::ScopedAssertNoThreadSuspension nts("Deoptimizing everything!");
+ art::instrumentation::Instrumentation* i = runtime_->GetInstrumentation();
+ i->ReJitEverything("libOpenJkdJvmti - Class Redefinition");
+}
+
jvmtiError Redefiner::Run() {
art::StackHandleScope<5> hs(self_);
// TODO We might want to have a global lock (or one based on the class being redefined at least)
@@ -341,7 +586,8 @@
art::ObjPtr<art::mirror::LongArray> original_dex_file_cookie(nullptr);
if (!UpdateJavaDexFile(java_dex_file.Get(),
new_dex_file_cookie.Get(),
- &original_dex_file_cookie)) {
+ &original_dex_file_cookie) ||
+ !AllocateObsoleteMethods(art_class.Get())) {
// Release suspendAll
runtime_->GetThreadList()->ResumeAll();
// Get back shared mutator lock as expected for return.
@@ -357,18 +603,20 @@
self_->TransitionFromSuspendedToRunnable();
return result_;
}
- // Update the ClassObjects Keep the old DexCache (and other stuff) around so we can restore
- // functions/fields.
- // Verify the new Class.
- // Failure then undo updates to class
- // Do stack walks and allocate obsolete methods
- // Shrink the obsolete method maps if possible?
- // TODO find appropriate class loader. Allocate new dex files array. Pause all java treads.
- // Replace dex files array. Do stack scan + allocate obsoletes. Remove array if possible.
- // TODO We might want to ensure that all threads are stopped for this!
- // AddDexToClassPath();
- // TODO
- // Release suspendAll
+ // Ensure that obsolete methods are deoptimized. This is needed since optimized methods may have
+ // pointers to their ArtMethod's stashed in registers that they then use to attempt to hit the
+ // DexCache.
+ // TODO This can fail (leave some methods optimized) near runtime methods (including
+ // quick-to-interpreter transition function).
+ // TODO Mingyao@ suggested we could maybe just do a retry loop instead of fixing the above.
+ // TODO We probably don't need this at all once we have a way to ensure that the
+ // current_art_method is never stashed in a (physical) register by the JIT and lost to the
+ // stack-walker.
+ EnsureObsoleteMethodsAreDeoptimized();
+ // TODO Verify the new Class.
+ // TODO Failure then undo updates to class
+ // TODO Shrink the obsolete method maps if possible?
+ // TODO find appropriate class loader.
// TODO Put this into a scoped thing.
runtime_->GetThreadList()->ResumeAll();
// Get back shared mutator lock as expected for return.
@@ -421,19 +669,23 @@
}
const art::DexFile::ProtoId* proto_id = dex_file_->FindProtoId(method_return_idx,
new_type_list);
- CHECK(proto_id != nullptr || old_type_list == nullptr);
// TODO Return false, cleanup.
+ CHECK(proto_id != nullptr || old_type_list == nullptr);
const art::DexFile::MethodId* method_id = dex_file_->FindMethodId(declaring_class_id,
*new_name_id,
*proto_id);
- CHECK(method_id != nullptr);
// TODO Return false, cleanup.
+ CHECK(method_id != nullptr);
uint32_t dex_method_idx = dex_file_->GetIndexForMethodId(*method_id);
method.SetDexMethodIndex(dex_method_idx);
linker->SetEntryPointsToInterpreter(&method);
method.SetCodeItemOffset(dex_file_->FindCodeItemOffset(*class_def, dex_method_idx));
method.SetDexCacheResolvedMethods(new_dex_cache->GetResolvedMethods(), image_pointer_size);
method.SetDexCacheResolvedTypes(new_dex_cache->GetResolvedTypes(), image_pointer_size);
+ if (!method.IsNative()) {
+ // Reset profiling info.
+ method.SetProfilingInfo(nullptr);
+ }
}
// Update the class fields.
// Need to update class last since the ArtMethod gets its DexFile from the class (which is needed