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1 //===-- Watchpoint.h --------------------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef LLDB_BREAKPOINT_WATCHPOINT_H
10 #define LLDB_BREAKPOINT_WATCHPOINT_H
11 
12 #include <memory>
13 #include <string>
14 
15 #include "lldb/Breakpoint/StoppointSite.h"
16 #include "lldb/Breakpoint/WatchpointOptions.h"
17 #include "lldb/Symbol/CompilerType.h"
18 #include "lldb/Target/Target.h"
19 #include "lldb/Utility/UserID.h"
20 #include "lldb/lldb-private.h"
21 
22 namespace lldb_private {
23 
24 class Watchpoint : public std::enable_shared_from_this<Watchpoint>,
25                    public StoppointSite {
26 public:
27   class WatchpointEventData : public EventData {
28   public:
29     WatchpointEventData(lldb::WatchpointEventType sub_type,
30                         const lldb::WatchpointSP &new_watchpoint_sp);
31 
32     ~WatchpointEventData() override;
33 
34     static ConstString GetFlavorString();
35 
36     ConstString GetFlavor() const override;
37 
38     lldb::WatchpointEventType GetWatchpointEventType() const;
39 
40     lldb::WatchpointSP &GetWatchpoint();
41 
42     void Dump(Stream *s) const override;
43 
44     static lldb::WatchpointEventType
45     GetWatchpointEventTypeFromEvent(const lldb::EventSP &event_sp);
46 
47     static lldb::WatchpointSP
48     GetWatchpointFromEvent(const lldb::EventSP &event_sp);
49 
50     static const WatchpointEventData *
51     GetEventDataFromEvent(const Event *event_sp);
52 
53   private:
54     lldb::WatchpointEventType m_watchpoint_event;
55     lldb::WatchpointSP m_new_watchpoint_sp;
56 
57     WatchpointEventData(const WatchpointEventData &) = delete;
58     const WatchpointEventData &operator=(const WatchpointEventData &) = delete;
59   };
60 
61   Watchpoint(Target &target, lldb::addr_t addr, uint32_t size,
62              const CompilerType *type, bool hardware = true);
63 
64   ~Watchpoint() override;
65 
66   void IncrementFalseAlarmsAndReviseHitCount();
67 
68   bool IsEnabled() const;
69 
70   // This doesn't really enable/disable the watchpoint.   It is currently just
71   // for use in the Process plugin's {Enable,Disable}Watchpoint, which should
72   // be used instead.
73   void SetEnabled(bool enabled, bool notify = true);
74 
75   bool IsHardware() const override;
76 
77   bool ShouldStop(StoppointCallbackContext *context) override;
78 
79   bool WatchpointRead() const;
80   bool WatchpointWrite() const;
81   uint32_t GetIgnoreCount() const;
82   void SetIgnoreCount(uint32_t n);
83   void SetWatchpointType(uint32_t type, bool notify = true);
84   void SetDeclInfo(const std::string &str);
85   std::string GetWatchSpec();
86   void SetWatchSpec(const std::string &str);
87 
88   // Snapshot management interface.
89   bool IsWatchVariable() const;
90   void SetWatchVariable(bool val);
91   bool CaptureWatchedValue(const ExecutionContext &exe_ctx);
92 
93   void GetDescription(Stream *s, lldb::DescriptionLevel level);
94   void Dump(Stream *s) const override;
95   void DumpSnapshots(Stream *s, const char *prefix = nullptr) const;
96   void DumpWithLevel(Stream *s, lldb::DescriptionLevel description_level) const;
GetTarget()97   Target &GetTarget() { return m_target; }
GetError()98   const Status &GetError() { return m_error; }
99 
100   /// Returns the WatchpointOptions structure set for this watchpoint.
101   ///
102   /// \return
103   ///     A pointer to this watchpoint's WatchpointOptions.
GetOptions()104   WatchpointOptions *GetOptions() { return &m_options; }
105 
106   /// Set the callback action invoked when the watchpoint is hit.
107   ///
108   /// \param[in] callback
109   ///    The method that will get called when the watchpoint is hit.
110   /// \param[in] callback_baton
111   ///    A void * pointer that will get passed back to the callback function.
112   /// \param[in] is_synchronous
113   ///    If \b true the callback will be run on the private event thread
114   ///    before the stop event gets reported.  If false, the callback will get
115   ///    handled on the public event thread after the stop has been posted.
116   void SetCallback(WatchpointHitCallback callback, void *callback_baton,
117                    bool is_synchronous = false);
118 
119   void SetCallback(WatchpointHitCallback callback,
120                    const lldb::BatonSP &callback_baton_sp,
121                    bool is_synchronous = false);
122 
123   void ClearCallback();
124 
125   /// Invoke the callback action when the watchpoint is hit.
126   ///
127   /// \param[in] context
128   ///     Described the watchpoint event.
129   ///
130   /// \return
131   ///     \b true if the target should stop at this watchpoint and \b false not.
132   bool InvokeCallback(StoppointCallbackContext *context);
133 
134   // Condition
135   /// Set the watchpoint's condition.
136   ///
137   /// \param[in] condition
138   ///    The condition expression to evaluate when the watchpoint is hit.
139   ///    Pass in nullptr to clear the condition.
140   void SetCondition(const char *condition);
141 
142   /// Return a pointer to the text of the condition expression.
143   ///
144   /// \return
145   ///    A pointer to the condition expression text, or nullptr if no
146   //     condition has been set.
147   const char *GetConditionText() const;
148 
149   void TurnOnEphemeralMode();
150 
151   void TurnOffEphemeralMode();
152 
153   bool IsDisabledDuringEphemeralMode();
154 
GetCompilerType()155   const CompilerType &GetCompilerType() { return m_type; }
156 
157 private:
158   friend class Target;
159   friend class WatchpointList;
160 
ResetHistoricValues()161   void ResetHistoricValues() {
162     m_old_value_sp.reset();
163     m_new_value_sp.reset();
164   }
165 
166   Target &m_target;
167   bool m_enabled;           // Is this watchpoint enabled
168   bool m_is_hardware;       // Is this a hardware watchpoint
169   bool m_is_watch_variable; // True if set via 'watchpoint set variable'.
170   bool m_is_ephemeral;      // True if the watchpoint is in the ephemeral mode,
171                             // meaning that it is
172   // undergoing a pair of temporary disable/enable actions to avoid recursively
173   // triggering further watchpoint events.
174   uint32_t m_disabled_count; // Keep track of the count that the watchpoint is
175                              // disabled while in ephemeral mode.
176   // At the end of the ephemeral mode when the watchpoint is to be enabled
177   // again, we check the count, if it is more than 1, it means the user-
178   // supplied actions actually want the watchpoint to be disabled!
179   uint32_t m_watch_read : 1, // 1 if we stop when the watched data is read from
180       m_watch_write : 1,     // 1 if we stop when the watched data is written to
181       m_watch_was_read : 1, // Set to 1 when watchpoint is hit for a read access
182       m_watch_was_written : 1;  // Set to 1 when watchpoint is hit for a write
183                                 // access
184   uint32_t m_ignore_count;      // Number of times to ignore this watchpoint
185   uint32_t m_false_alarms;      // Number of false alarms.
186   std::string m_decl_str;       // Declaration information, if any.
187   std::string m_watch_spec_str; // Spec for the watchpoint.
188   lldb::ValueObjectSP m_old_value_sp;
189   lldb::ValueObjectSP m_new_value_sp;
190   CompilerType m_type;
191   Status m_error; // An error object describing errors associated with this
192                   // watchpoint.
193   WatchpointOptions
194       m_options; // Settable watchpoint options, which is a delegate to handle
195                  // the callback machinery.
196   bool m_being_created;
197 
198   std::unique_ptr<UserExpression> m_condition_up; // The condition to test.
199 
SetID(lldb::watch_id_t id)200   void SetID(lldb::watch_id_t id) { m_id = id; }
201 
202   void SendWatchpointChangedEvent(lldb::WatchpointEventType eventKind);
203 
204   void SendWatchpointChangedEvent(WatchpointEventData *data);
205 
206   Watchpoint(const Watchpoint &) = delete;
207   const Watchpoint &operator=(const Watchpoint &) = delete;
208 };
209 
210 } // namespace lldb_private
211 
212 #endif // LLDB_BREAKPOINT_WATCHPOINT_H
213