| /* |
| * Copyright (C) 2014 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "quick_exception_handler.h" |
| |
| #include "arch/context.h" |
| #include "dex_instruction.h" |
| #include "entrypoints/entrypoint_utils.h" |
| #include "handle_scope-inl.h" |
| #include "mirror/art_method-inl.h" |
| #include "mirror/class-inl.h" |
| #include "mirror/class_loader.h" |
| #include "mirror/throwable.h" |
| #include "verifier/method_verifier.h" |
| |
| namespace art { |
| |
| static constexpr bool kDebugExceptionDelivery = false; |
| static constexpr size_t kInvalidFrameDepth = 0xffffffff; |
| |
| QuickExceptionHandler::QuickExceptionHandler(Thread* self, bool is_deoptimization) |
| : self_(self), context_(self->GetLongJumpContext()), is_deoptimization_(is_deoptimization), |
| method_tracing_active_(is_deoptimization || |
| Runtime::Current()->GetInstrumentation()->AreExitStubsInstalled()), |
| handler_quick_frame_(nullptr), handler_quick_frame_pc_(0), handler_method_(nullptr), |
| handler_dex_pc_(0), clear_exception_(false), handler_frame_depth_(kInvalidFrameDepth) { |
| } |
| |
| // Finds catch handler or prepares for deoptimization. |
| class CatchBlockStackVisitor FINAL : public StackVisitor { |
| public: |
| CatchBlockStackVisitor(Thread* self, Context* context, Handle<mirror::Throwable>* exception, |
| QuickExceptionHandler* exception_handler) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| : StackVisitor(self, context), self_(self), exception_(exception), |
| exception_handler_(exception_handler) { |
| } |
| |
| bool VisitFrame() OVERRIDE SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { |
| mirror::ArtMethod* method = GetMethod(); |
| exception_handler_->SetHandlerFrameDepth(GetFrameDepth()); |
| if (method == nullptr) { |
| // This is the upcall, we remember the frame and last pc so that we may long jump to them. |
| exception_handler_->SetHandlerQuickFramePc(GetCurrentQuickFramePc()); |
| exception_handler_->SetHandlerQuickFrame(GetCurrentQuickFrame()); |
| uint32_t next_dex_pc; |
| mirror::ArtMethod* next_art_method; |
| bool has_next = GetNextMethodAndDexPc(&next_art_method, &next_dex_pc); |
| // Report the method that did the down call as the handler. |
| exception_handler_->SetHandlerDexPc(next_dex_pc); |
| exception_handler_->SetHandlerMethod(next_art_method); |
| if (!has_next) { |
| // No next method? Check exception handler is set up for the unhandled exception handler |
| // case. |
| DCHECK_EQ(0U, exception_handler_->GetHandlerDexPc()); |
| DCHECK(nullptr == exception_handler_->GetHandlerMethod()); |
| } |
| return false; // End stack walk. |
| } |
| if (method->IsRuntimeMethod()) { |
| // Ignore callee save method. |
| DCHECK(method->IsCalleeSaveMethod()); |
| return true; |
| } |
| StackHandleScope<1> hs(self_); |
| return HandleTryItems(hs.NewHandle(method)); |
| } |
| |
| private: |
| bool HandleTryItems(Handle<mirror::ArtMethod> method) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { |
| uint32_t dex_pc = DexFile::kDexNoIndex; |
| if (!method->IsNative()) { |
| dex_pc = GetDexPc(); |
| } |
| if (dex_pc != DexFile::kDexNoIndex) { |
| bool clear_exception = false; |
| StackHandleScope<1> hs(Thread::Current()); |
| Handle<mirror::Class> to_find(hs.NewHandle((*exception_)->GetClass())); |
| uint32_t found_dex_pc = mirror::ArtMethod::FindCatchBlock(method, to_find, dex_pc, |
| &clear_exception); |
| exception_handler_->SetClearException(clear_exception); |
| if (found_dex_pc != DexFile::kDexNoIndex) { |
| exception_handler_->SetHandlerMethod(method.Get()); |
| exception_handler_->SetHandlerDexPc(found_dex_pc); |
| exception_handler_->SetHandlerQuickFramePc(method->ToNativePc(found_dex_pc)); |
| exception_handler_->SetHandlerQuickFrame(GetCurrentQuickFrame()); |
| return false; // End stack walk. |
| } |
| } |
| return true; // Continue stack walk. |
| } |
| |
| Thread* const self_; |
| // The exception we're looking for the catch block of. |
| Handle<mirror::Throwable>* exception_; |
| // The quick exception handler we're visiting for. |
| QuickExceptionHandler* const exception_handler_; |
| |
| DISALLOW_COPY_AND_ASSIGN(CatchBlockStackVisitor); |
| }; |
| |
| void QuickExceptionHandler::FindCatch(const ThrowLocation& throw_location, |
| mirror::Throwable* exception, |
| bool is_exception_reported) { |
| DCHECK(!is_deoptimization_); |
| if (kDebugExceptionDelivery) { |
| mirror::String* msg = exception->GetDetailMessage(); |
| std::string str_msg(msg != nullptr ? msg->ToModifiedUtf8() : ""); |
| self_->DumpStack(LOG(INFO) << "Delivering exception: " << PrettyTypeOf(exception) |
| << ": " << str_msg << "\n"); |
| } |
| StackHandleScope<1> hs(self_); |
| Handle<mirror::Throwable> exception_ref(hs.NewHandle(exception)); |
| |
| // Walk the stack to find catch handler or prepare for deoptimization. |
| CatchBlockStackVisitor visitor(self_, context_, &exception_ref, this); |
| visitor.WalkStack(true); |
| |
| if (kDebugExceptionDelivery) { |
| if (handler_quick_frame_->AsMirrorPtr() == nullptr) { |
| LOG(INFO) << "Handler is upcall"; |
| } |
| if (handler_method_ != nullptr) { |
| const DexFile& dex_file = *handler_method_->GetDeclaringClass()->GetDexCache()->GetDexFile(); |
| int line_number = dex_file.GetLineNumFromPC(handler_method_, handler_dex_pc_); |
| LOG(INFO) << "Handler: " << PrettyMethod(handler_method_) << " (line: " << line_number << ")"; |
| } |
| } |
| if (clear_exception_) { |
| // Exception was cleared as part of delivery. |
| DCHECK(!self_->IsExceptionPending()); |
| } else { |
| // Put exception back in root set with clear throw location. |
| self_->SetException(ThrowLocation(), exception_ref.Get()); |
| self_->SetExceptionReportedToInstrumentation(is_exception_reported); |
| } |
| // The debugger may suspend this thread and walk its stack. Let's do this before popping |
| // instrumentation frames. |
| if (!is_exception_reported) { |
| instrumentation::Instrumentation* instrumentation = Runtime::Current()->GetInstrumentation(); |
| instrumentation->ExceptionCaughtEvent(self_, throw_location, handler_method_, handler_dex_pc_, |
| exception_ref.Get()); |
| // We're not catching this exception but let's remind we already reported the exception above |
| // to avoid reporting it twice. |
| self_->SetExceptionReportedToInstrumentation(true); |
| } |
| bool caught_exception = (handler_method_ != nullptr && handler_dex_pc_ != DexFile::kDexNoIndex); |
| if (caught_exception) { |
| // We're catching this exception so we finish reporting it. We do it here to avoid doing it |
| // in the compiled code. |
| self_->SetExceptionReportedToInstrumentation(false); |
| } |
| } |
| |
| // Prepares deoptimization. |
| class DeoptimizeStackVisitor FINAL : public StackVisitor { |
| public: |
| DeoptimizeStackVisitor(Thread* self, Context* context, QuickExceptionHandler* exception_handler) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| : StackVisitor(self, context), self_(self), exception_handler_(exception_handler), |
| prev_shadow_frame_(nullptr) { |
| CHECK(!self_->HasDeoptimizationShadowFrame()); |
| } |
| |
| bool VisitFrame() OVERRIDE SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { |
| exception_handler_->SetHandlerFrameDepth(GetFrameDepth()); |
| mirror::ArtMethod* method = GetMethod(); |
| if (method == nullptr) { |
| // This is the upcall, we remember the frame and last pc so that we may long jump to them. |
| exception_handler_->SetHandlerQuickFramePc(GetCurrentQuickFramePc()); |
| exception_handler_->SetHandlerQuickFrame(GetCurrentQuickFrame()); |
| return false; // End stack walk. |
| } else if (method->IsRuntimeMethod()) { |
| // Ignore callee save method. |
| DCHECK(method->IsCalleeSaveMethod()); |
| return true; |
| } else { |
| return HandleDeoptimization(method); |
| } |
| } |
| |
| private: |
| static VRegKind GetVRegKind(uint16_t reg, const std::vector<int32_t>& kinds) { |
| return static_cast<VRegKind>(kinds.at(reg * 2)); |
| } |
| |
| bool HandleDeoptimization(mirror::ArtMethod* m) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { |
| const DexFile::CodeItem* code_item = m->GetCodeItem(); |
| CHECK(code_item != nullptr); |
| uint16_t num_regs = code_item->registers_size_; |
| uint32_t dex_pc = GetDexPc(); |
| const Instruction* inst = Instruction::At(code_item->insns_ + dex_pc); |
| uint32_t new_dex_pc = dex_pc + inst->SizeInCodeUnits(); |
| ShadowFrame* new_frame = ShadowFrame::Create(num_regs, nullptr, m, new_dex_pc); |
| StackHandleScope<3> hs(self_); |
| mirror::Class* declaring_class = m->GetDeclaringClass(); |
| Handle<mirror::DexCache> h_dex_cache(hs.NewHandle(declaring_class->GetDexCache())); |
| Handle<mirror::ClassLoader> h_class_loader(hs.NewHandle(declaring_class->GetClassLoader())); |
| Handle<mirror::ArtMethod> h_method(hs.NewHandle(m)); |
| verifier::MethodVerifier verifier(self_, h_dex_cache->GetDexFile(), h_dex_cache, h_class_loader, |
| &m->GetClassDef(), code_item, m->GetDexMethodIndex(), |
| h_method, m->GetAccessFlags(), false, true, true); |
| verifier.Verify(); |
| const std::vector<int32_t> kinds(verifier.DescribeVRegs(dex_pc)); |
| for (uint16_t reg = 0; reg < num_regs; ++reg) { |
| VRegKind kind = GetVRegKind(reg, kinds); |
| switch (kind) { |
| case kUndefined: |
| new_frame->SetVReg(reg, 0xEBADDE09); |
| break; |
| case kConstant: |
| new_frame->SetVReg(reg, kinds.at((reg * 2) + 1)); |
| break; |
| case kReferenceVReg: |
| new_frame->SetVRegReference(reg, |
| reinterpret_cast<mirror::Object*>(GetVReg(m, reg, kind))); |
| break; |
| case kLongLoVReg: |
| if (GetVRegKind(reg + 1, kinds) == kLongHiVReg) { |
| // Treat it as a "long" register pair. |
| new_frame->SetVRegLong(reg, GetVRegPair(m, reg, kLongLoVReg, kLongHiVReg)); |
| } else { |
| new_frame->SetVReg(reg, GetVReg(m, reg, kind)); |
| } |
| break; |
| case kLongHiVReg: |
| if (GetVRegKind(reg - 1, kinds) == kLongLoVReg) { |
| // Nothing to do: we treated it as a "long" register pair. |
| } else { |
| new_frame->SetVReg(reg, GetVReg(m, reg, kind)); |
| } |
| break; |
| case kDoubleLoVReg: |
| if (GetVRegKind(reg + 1, kinds) == kDoubleHiVReg) { |
| // Treat it as a "double" register pair. |
| new_frame->SetVRegLong(reg, GetVRegPair(m, reg, kDoubleLoVReg, kDoubleHiVReg)); |
| } else { |
| new_frame->SetVReg(reg, GetVReg(m, reg, kind)); |
| } |
| break; |
| case kDoubleHiVReg: |
| if (GetVRegKind(reg - 1, kinds) == kDoubleLoVReg) { |
| // Nothing to do: we treated it as a "double" register pair. |
| } else { |
| new_frame->SetVReg(reg, GetVReg(m, reg, kind)); |
| } |
| break; |
| default: |
| new_frame->SetVReg(reg, GetVReg(m, reg, kind)); |
| break; |
| } |
| } |
| if (prev_shadow_frame_ != nullptr) { |
| prev_shadow_frame_->SetLink(new_frame); |
| } else { |
| self_->SetDeoptimizationShadowFrame(new_frame); |
| } |
| prev_shadow_frame_ = new_frame; |
| return true; |
| } |
| |
| Thread* const self_; |
| QuickExceptionHandler* const exception_handler_; |
| ShadowFrame* prev_shadow_frame_; |
| |
| DISALLOW_COPY_AND_ASSIGN(DeoptimizeStackVisitor); |
| }; |
| |
| void QuickExceptionHandler::DeoptimizeStack() { |
| DCHECK(is_deoptimization_); |
| if (kDebugExceptionDelivery) { |
| self_->DumpStack(LOG(INFO) << "Deoptimizing: "); |
| } |
| |
| DeoptimizeStackVisitor visitor(self_, context_, this); |
| visitor.WalkStack(true); |
| |
| // Restore deoptimization exception |
| self_->SetException(ThrowLocation(), Thread::GetDeoptimizationException()); |
| } |
| |
| // Unwinds all instrumentation stack frame prior to catch handler or upcall. |
| class InstrumentationStackVisitor : public StackVisitor { |
| public: |
| InstrumentationStackVisitor(Thread* self, bool is_deoptimization, size_t frame_depth) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| : StackVisitor(self, nullptr), |
| self_(self), frame_depth_(frame_depth), |
| instrumentation_frames_to_pop_(0) { |
| CHECK_NE(frame_depth_, kInvalidFrameDepth); |
| } |
| |
| bool VisitFrame() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { |
| size_t current_frame_depth = GetFrameDepth(); |
| if (current_frame_depth < frame_depth_) { |
| CHECK(GetMethod() != nullptr); |
| if (UNLIKELY(GetQuickInstrumentationExitPc() == GetReturnPc())) { |
| ++instrumentation_frames_to_pop_; |
| } |
| return true; |
| } else { |
| // We reached the frame of the catch handler or the upcall. |
| return false; |
| } |
| } |
| |
| size_t GetInstrumentationFramesToPop() const { |
| return instrumentation_frames_to_pop_; |
| } |
| |
| private: |
| Thread* const self_; |
| const size_t frame_depth_; |
| size_t instrumentation_frames_to_pop_; |
| |
| DISALLOW_COPY_AND_ASSIGN(InstrumentationStackVisitor); |
| }; |
| |
| void QuickExceptionHandler::UpdateInstrumentationStack() { |
| if (method_tracing_active_) { |
| InstrumentationStackVisitor visitor(self_, is_deoptimization_, handler_frame_depth_); |
| visitor.WalkStack(true); |
| |
| size_t instrumentation_frames_to_pop = visitor.GetInstrumentationFramesToPop(); |
| instrumentation::Instrumentation* instrumentation = Runtime::Current()->GetInstrumentation(); |
| for (size_t i = 0; i < instrumentation_frames_to_pop; ++i) { |
| instrumentation->PopMethodForUnwind(self_, is_deoptimization_); |
| } |
| } |
| } |
| |
| void QuickExceptionHandler::DoLongJump() { |
| // Place context back on thread so it will be available when we continue. |
| self_->ReleaseLongJumpContext(context_); |
| context_->SetSP(reinterpret_cast<uintptr_t>(handler_quick_frame_)); |
| CHECK_NE(handler_quick_frame_pc_, 0u); |
| context_->SetPC(handler_quick_frame_pc_); |
| context_->SmashCallerSaves(); |
| context_->DoLongJump(); |
| } |
| |
| } // namespace art |