runtime/quick_exception_handler.h

/*
 * 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.
 */

#ifndef ART_RUNTIME_QUICK_EXCEPTION_HANDLER_H_
#define ART_RUNTIME_QUICK_EXCEPTION_HANDLER_H_

#include <android-base/logging.h>
#include <cstdint>
#include <optional>

#include "base/array_ref.h"
#include "base/macros.h"
#include "base/mutex.h"
#include "deoptimization_kind.h"
#include "stack_map.h"
#include "stack_reference.h"

namespace art {

namespace mirror {
class Throwable;
}  // namespace mirror
class ArtMethod;
class Context;
class OatQuickMethodHeader;
class Thread;
class ShadowFrame;
class StackVisitor;

// Manages exception delivery for Quick backend.
class QuickExceptionHandler {
 public:
  QuickExceptionHandler(Thread* self, bool is_deoptimization)
      REQUIRES_SHARED(Locks::mutator_lock_);

  NO_RETURN ~QuickExceptionHandler() {
    LOG(FATAL) << "UNREACHABLE";  // Expected to take long jump.
    UNREACHABLE();
  }

  // Find the catch handler for the given exception and call all required Instrumentation methods.
  // Note this might result in the exception being caught being different from 'exception'.
  void FindCatch(ObjPtr<mirror::Throwable> exception, bool is_method_exit_exception)
      REQUIRES_SHARED(Locks::mutator_lock_);

  // Deoptimize the stack to the upcall/some code that's not deoptimizeable. For
  // every compiled frame, we create a "copy" shadow frame that will be executed
  // with the interpreter.
  void DeoptimizeStack() REQUIRES_SHARED(Locks::mutator_lock_);

  // Deoptimize a single frame. It's directly triggered from compiled code. It
  // has the following properties:
  // - It deoptimizes a single frame, which can include multiple inlined frames.
  // - It doesn't have return result or pending exception at the deoptimization point.
  // - It always deoptimizes, even if IsDeoptimizeable() returns false for the
  //   code, since HDeoptimize always saves the full environment. So it overrides
  //   the result of IsDeoptimizeable().
  // - It can be either full-fragment, or partial-fragment deoptimization, depending
  //   on whether that single frame covers full or partial fragment.
  void DeoptimizeSingleFrame(DeoptimizationKind kind) REQUIRES_SHARED(Locks::mutator_lock_);

  void DeoptimizePartialFragmentFixup(uintptr_t return_pc)
      REQUIRES_SHARED(Locks::mutator_lock_);

  // Update the instrumentation stack by removing all methods that will be unwound
  // by the exception being thrown.
  // Return the return pc of the last frame that's unwound.
  uintptr_t UpdateInstrumentationStack() REQUIRES_SHARED(Locks::mutator_lock_);

  // Set up environment before delivering an exception to optimized code.
  void SetCatchEnvironmentForOptimizedHandler(StackVisitor* stack_visitor)
      REQUIRES_SHARED(Locks::mutator_lock_);

  // Long jump either to a catch handler or to the upcall.
  NO_RETURN void DoLongJump(bool smash_caller_saves = true) REQUIRES_SHARED(Locks::mutator_lock_);

  void SetHandlerQuickFrame(ArtMethod** handler_quick_frame) {
    handler_quick_frame_ = handler_quick_frame;
  }

  void SetHandlerQuickFramePc(uintptr_t handler_quick_frame_pc) {
    handler_quick_frame_pc_ = handler_quick_frame_pc;
  }

  void SetHandlerMethodHeader(const OatQuickMethodHeader* handler_method_header) {
    handler_method_header_ = handler_method_header;
  }

  void SetHandlerQuickArg0(uintptr_t handler_quick_arg0) {
    handler_quick_arg0_ = handler_quick_arg0;
  }

  ArtMethod* GetHandlerMethod() const {
    return *handler_quick_frame_;
  }

  ArrayRef<const uint32_t> GetHandlerDexPcList() const {
    DCHECK(handler_dex_pc_list_.has_value());
    return ArrayRef<const uint32_t>(handler_dex_pc_list_.value());
  }

  void SetHandlerDexPcList(std::vector<uint32_t>&& handler_dex_pc_list) {
    handler_dex_pc_list_ = handler_dex_pc_list;
  }

  uint32_t GetCatchStackMapRow() const {
    return catch_stack_map_row_;
  }

  void SetCatchStackMapRow(uint32_t stack_map_row) {
    catch_stack_map_row_ = stack_map_row;
  }

  bool GetClearException() const {
    return clear_exception_;
  }

  void SetClearException(bool clear_exception) {
    clear_exception_ = clear_exception;
  }

  void SetHandlerFrameDepth(size_t frame_depth) {
    handler_frame_depth_ = frame_depth;
  }

  bool IsFullFragmentDone() const {
    return full_fragment_done_;
  }

  void SetFullFragmentDone(bool full_fragment_done) {
    full_fragment_done_ = full_fragment_done;
  }

  // Walk the stack frames of the given thread, printing out non-runtime methods with their types
  // of frames. Helps to verify that partial-fragment deopt really works as expected.
  static void DumpFramesWithType(Thread* self, bool details = false)
      REQUIRES_SHARED(Locks::mutator_lock_);

 private:
  Thread* const self_;
  Context* const context_;
  // Should we deoptimize the stack?
  const bool is_deoptimization_;
  // Is method tracing active?
  const bool method_tracing_active_;
  // Quick frame with found handler or last frame if no handler found.
  ArtMethod** handler_quick_frame_;
  // PC to branch to for the handler.
  uintptr_t handler_quick_frame_pc_;
  // Quick code of the handler.
  const OatQuickMethodHeader* handler_method_header_;
  // The value for argument 0.
  uintptr_t handler_quick_arg0_;
  // The handler's dex PC list including the inline dex_pcs. The dex_pcs are ordered from outermost
  // to innermost. An empty list implies an uncaught exception.
  // Marked as optional so that we can make sure we destroy it before doing a long jump.
  std::optional<std::vector<uint32_t>> handler_dex_pc_list_;
  // StackMap row corresponding to the found catch.
  uint32_t catch_stack_map_row_;
  // Should the exception be cleared as the catch block has no move-exception?
  bool clear_exception_;
  // Frame depth of the catch handler or the upcall.
  size_t handler_frame_depth_;
  // Does the handler successfully walk the full fragment (not stopped
  // by some code that's not deoptimizeable)? Even single-frame deoptimization
  // can set this to true if the fragment contains only one quick frame.
  bool full_fragment_done_;

  void PrepareForLongJumpToInvokeStubOrInterpreterBridge()
      REQUIRES_SHARED(Locks::mutator_lock_);

  DISALLOW_COPY_AND_ASSIGN(QuickExceptionHandler);
};

}  // namespace art
#endif  // ART_RUNTIME_QUICK_EXCEPTION_HANDLER_H_