Watchpoint.h

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//===-- Watchpoint.h --------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef liblldb_Watchpoint_h_
#define liblldb_Watchpoint_h_

#include <memory>
#include <string>

#include "lldb/Breakpoint/StoppointLocation.h"
#include "lldb/Breakpoint/WatchpointOptions.h"
#include "lldb/Symbol/CompilerType.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/UserID.h"
#include "lldb/lldb-private.h"

namespace lldb_private {

class Watchpoint : public std::enable_shared_from_this<Watchpoint>,
                   public StoppointLocation {
public:
  class WatchpointEventData : public EventData {
  public:
    WatchpointEventData(lldb::WatchpointEventType sub_type,
                        const lldb::WatchpointSP &new_watchpoint_sp);

    ~WatchpointEventData() override;

    static ConstString GetFlavorString();

    ConstString GetFlavor() const override;

    lldb::WatchpointEventType GetWatchpointEventType() const;

    lldb::WatchpointSP &GetWatchpoint();

    void Dump(Stream *s) const override;

    static lldb::WatchpointEventType
    GetWatchpointEventTypeFromEvent(const lldb::EventSP &event_sp);

    static lldb::WatchpointSP
    GetWatchpointFromEvent(const lldb::EventSP &event_sp);

    static const WatchpointEventData *
    GetEventDataFromEvent(const Event *event_sp);

  private:
    lldb::WatchpointEventType m_watchpoint_event;
    lldb::WatchpointSP m_new_watchpoint_sp;

    DISALLOW_COPY_AND_ASSIGN(WatchpointEventData);
  };

  Watchpoint(Target &target, lldb::addr_t addr, uint32_t size,
             const CompilerType *type, bool hardware = true);

  ~Watchpoint() override;

  void IncrementFalseAlarmsAndReviseHitCount();

  bool IsEnabled() const;

  // This doesn't really enable/disable the watchpoint.   It is currently just
  // for use in the Process plugin's {Enable,Disable}Watchpoint, which should
  // be used instead.
  
  void SetEnabled(bool enabled, bool notify = true);

  bool IsHardware() const override;

  bool ShouldStop(StoppointCallbackContext *context) override;

  bool WatchpointRead() const;
  bool WatchpointWrite() const;
  uint32_t GetIgnoreCount() const;
  void SetIgnoreCount(uint32_t n);
  void SetWatchpointType(uint32_t type, bool notify = true);
  void SetDeclInfo(const std::string &str);
  std::string GetWatchSpec();
  void SetWatchSpec(const std::string &str);

  // Snapshot management interface.
  bool IsWatchVariable() const;
  void SetWatchVariable(bool val);
  bool CaptureWatchedValue(const ExecutionContext &exe_ctx);

  void GetDescription(Stream *s, lldb::DescriptionLevel level);
  void Dump(Stream *s) const override;
  void DumpSnapshots(Stream *s, const char *prefix = nullptr) const;
  void DumpWithLevel(Stream *s, lldb::DescriptionLevel description_level) const;
  Target &GetTarget() { return m_target; }
  const Status &GetError() { return m_error; }

  /// Returns the WatchpointOptions structure set for this watchpoint.
  ///
  /// \return
  ///     A pointer to this watchpoint's WatchpointOptions.
  WatchpointOptions *GetOptions() { return &m_options; }

  /// Set the callback action invoked when the watchpoint is hit.
  ///
  /// \param[in] callback
  ///    The method that will get called when the watchpoint is hit.
  /// \param[in] callback_baton
  ///    A void * pointer that will get passed back to the callback function.
  /// \param[in] is_synchronous
  ///    If \b true the callback will be run on the private event thread
  ///    before the stop event gets reported.  If false, the callback will get
  ///    handled on the public event thread after the stop has been posted.
  ///
  /// \return
  ///    \b true if the process should stop when you hit the watchpoint.
  ///    \b false if it should continue.
  void SetCallback(WatchpointHitCallback callback, void *callback_baton,
                   bool is_synchronous = false);

  void SetCallback(WatchpointHitCallback callback,
                   const lldb::BatonSP &callback_baton_sp,
                   bool is_synchronous = false);

  void ClearCallback();

  /// Invoke the callback action when the watchpoint is hit.
  ///
  /// \param[in] context
  ///     Described the watchpoint event.
  ///
  /// \return
  ///     \b true if the target should stop at this watchpoint and \b false not.
  bool InvokeCallback(StoppointCallbackContext *context);

  // Condition
  /// Set the watchpoint's condition.
  ///
  /// \param[in] condition
  ///    The condition expression to evaluate when the watchpoint is hit.
  ///    Pass in nullptr to clear the condition.
  void SetCondition(const char *condition);

  /// Return a pointer to the text of the condition expression.
  ///
  /// \return
  ///    A pointer to the condition expression text, or nullptr if no
  //     condition has been set.
  const char *GetConditionText() const;

  void TurnOnEphemeralMode();

  void TurnOffEphemeralMode();

  bool IsDisabledDuringEphemeralMode();

  const CompilerType &GetCompilerType() { return m_type; }

private:
  friend class Target;
  friend class WatchpointList;

  void ResetHitCount() { m_hit_count = 0; }

  void ResetHistoricValues() {
    m_old_value_sp.reset(nullptr);
    m_new_value_sp.reset(nullptr);
  }

  Target &m_target;
  bool m_enabled;           // Is this watchpoint enabled
  bool m_is_hardware;       // Is this a hardware watchpoint
  bool m_is_watch_variable; // True if set via 'watchpoint set variable'.
  bool m_is_ephemeral;      // True if the watchpoint is in the ephemeral mode,
                            // meaning that it is
  // undergoing a pair of temporary disable/enable actions to avoid recursively
  // triggering further watchpoint events.
  uint32_t m_disabled_count; // Keep track of the count that the watchpoint is
                             // disabled while in ephemeral mode.
  // At the end of the ephemeral mode when the watchpoint is to be enabled
  // again, we check the count, if it is more than 1, it means the user-
  // supplied actions actually want the watchpoint to be disabled!
  uint32_t m_watch_read : 1, // 1 if we stop when the watched data is read from
      m_watch_write : 1,     // 1 if we stop when the watched data is written to
      m_watch_was_read : 1, // Set to 1 when watchpoint is hit for a read access
      m_watch_was_written : 1;  // Set to 1 when watchpoint is hit for a write
                                // access
  uint32_t m_ignore_count;      // Number of times to ignore this watchpoint
  uint32_t m_false_alarms;      // Number of false alarms.
  std::string m_decl_str;       // Declaration information, if any.
  std::string m_watch_spec_str; // Spec for the watchpoint.
  lldb::ValueObjectSP m_old_value_sp;
  lldb::ValueObjectSP m_new_value_sp;
  CompilerType m_type;
  Status m_error; // An error object describing errors associated with this
                  // watchpoint.
  WatchpointOptions
      m_options; // Settable watchpoint options, which is a delegate to handle
                 // the callback machinery.
  bool m_being_created;

  std::unique_ptr<UserExpression> m_condition_up; // The condition to test.

  void SetID(lldb::watch_id_t id) { m_loc_id = id; }

  void SendWatchpointChangedEvent(lldb::WatchpointEventType eventKind);

  void SendWatchpointChangedEvent(WatchpointEventData *data);

  DISALLOW_COPY_AND_ASSIGN(Watchpoint);
};

} // namespace lldb_private

#endif // liblldb_Watchpoint_h_