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 llvm::StringRef GetFlavorString();
35 
36     llvm::StringRef 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   bool IsEnabled() const;
67 
68   // This doesn't really enable/disable the watchpoint.   It is currently just
69   // for use in the Process plugin's {Enable,Disable}Watchpoint, which should
70   // be used instead.
71   void SetEnabled(bool enabled, bool notify = true);
72 
73   bool IsHardware() const override;
74 
75   bool ShouldStop(StoppointCallbackContext *context) override;
76 
77   bool WatchpointRead() const;
78   bool WatchpointWrite() const;
79   uint32_t GetIgnoreCount() const;
80   void SetIgnoreCount(uint32_t n);
81   void SetWatchpointType(uint32_t type, bool notify = true);
82   void SetDeclInfo(const std::string &str);
83   std::string GetWatchSpec();
84   void SetWatchSpec(const std::string &str);
85 
86   // Snapshot management interface.
87   bool IsWatchVariable() const;
88   void SetWatchVariable(bool val);
89   bool CaptureWatchedValue(const ExecutionContext &exe_ctx);
90 
91   /// \struct WatchpointVariableContext
92   /// \brief Represents the context of a watchpoint variable.
93   ///
94   /// This struct encapsulates the information related to a watchpoint variable,
95   /// including the watch ID and the execution context in which it is being
96   /// used. This struct is passed as a Baton to the \b
97   /// VariableWatchpointDisabler breakpoint callback.
98   struct WatchpointVariableContext {
99     /// \brief Constructor for WatchpointVariableContext.
100     /// \param watch_id The ID of the watchpoint.
101     /// \param exe_ctx The execution context associated with the watchpoint.
102     WatchpointVariableContext(lldb::watch_id_t watch_id,
103                               ExecutionContext exe_ctx)
104         : watch_id(watch_id), exe_ctx(exe_ctx) {}
105 
106     lldb::watch_id_t watch_id; ///< The ID of the watchpoint.
107     ExecutionContext
108         exe_ctx; ///< The execution context associated with the watchpoint.
109   };
110 
111   class WatchpointVariableBaton : public TypedBaton<WatchpointVariableContext> {
112   public:
113     WatchpointVariableBaton(std::unique_ptr<WatchpointVariableContext> Data)
114         : TypedBaton(std::move(Data)) {}
115   };
116 
117   bool SetupVariableWatchpointDisabler(lldb::StackFrameSP frame_sp) const;
118 
119   /// Callback routine to disable the watchpoint set on a local variable when
120   ///  it goes out of scope.
121   static bool VariableWatchpointDisabler(
122       void *baton, lldb_private::StoppointCallbackContext *context,
123       lldb::user_id_t break_id, lldb::user_id_t break_loc_id);
124 
125   void GetDescription(Stream *s, lldb::DescriptionLevel level);
126   void Dump(Stream *s) const override;
127   void DumpSnapshots(Stream *s, const char *prefix = nullptr) const;
128   void DumpWithLevel(Stream *s, lldb::DescriptionLevel description_level) const;
129   Target &GetTarget() { return m_target; }
130   const Status &GetError() { return m_error; }
131 
132   /// Returns the WatchpointOptions structure set for this watchpoint.
133   ///
134   /// \return
135   ///     A pointer to this watchpoint's WatchpointOptions.
136   WatchpointOptions *GetOptions() { return &m_options; }
137 
138   /// Set the callback action invoked when the watchpoint is hit.
139   ///
140   /// \param[in] callback
141   ///    The method that will get called when the watchpoint is hit.
142   /// \param[in] callback_baton
143   ///    A void * pointer that will get passed back to the callback function.
144   /// \param[in] is_synchronous
145   ///    If \b true the callback will be run on the private event thread
146   ///    before the stop event gets reported.  If false, the callback will get
147   ///    handled on the public event thread after the stop has been posted.
148   void SetCallback(WatchpointHitCallback callback, void *callback_baton,
149                    bool is_synchronous = false);
150 
151   void SetCallback(WatchpointHitCallback callback,
152                    const lldb::BatonSP &callback_baton_sp,
153                    bool is_synchronous = false);
154 
155   void ClearCallback();
156 
157   /// Invoke the callback action when the watchpoint is hit.
158   ///
159   /// \param[in] context
160   ///     Described the watchpoint event.
161   ///
162   /// \return
163   ///     \b true if the target should stop at this watchpoint and \b false not.
164   bool InvokeCallback(StoppointCallbackContext *context);
165 
166   // Condition
167   /// Set the watchpoint's condition.
168   ///
169   /// \param[in] condition
170   ///    The condition expression to evaluate when the watchpoint is hit.
171   ///    Pass in nullptr to clear the condition.
172   void SetCondition(const char *condition);
173 
174   /// Return a pointer to the text of the condition expression.
175   ///
176   /// \return
177   ///    A pointer to the condition expression text, or nullptr if no
178   //     condition has been set.
179   const char *GetConditionText() const;
180 
181   void TurnOnEphemeralMode();
182 
183   void TurnOffEphemeralMode();
184 
185   bool IsDisabledDuringEphemeralMode();
186 
187   const CompilerType &GetCompilerType() { return m_type; }
188 
189 private:
190   friend class Target;
191   friend class WatchpointList;
192   friend class StopInfoWatchpoint; // This needs to call UndoHitCount()
193 
194   void ResetHistoricValues() {
195     m_old_value_sp.reset();
196     m_new_value_sp.reset();
197   }
198 
199   void UndoHitCount() { m_hit_counter.Decrement(); }
200 
201   Target &m_target;
202   bool m_enabled;           // Is this watchpoint enabled
203   bool m_is_hardware;       // Is this a hardware watchpoint
204   bool m_is_watch_variable; // True if set via 'watchpoint set variable'.
205   bool m_is_ephemeral;      // True if the watchpoint is in the ephemeral mode,
206                             // meaning that it is
207   // undergoing a pair of temporary disable/enable actions to avoid recursively
208   // triggering further watchpoint events.
209   uint32_t m_disabled_count; // Keep track of the count that the watchpoint is
210                              // disabled while in ephemeral mode.
211   // At the end of the ephemeral mode when the watchpoint is to be enabled
212   // again, we check the count, if it is more than 1, it means the user-
213   // supplied actions actually want the watchpoint to be disabled!
214   uint32_t m_watch_read : 1, // 1 if we stop when the watched data is read from
215       m_watch_write : 1;     // 1 if we stop when the watched data is written to
216   uint32_t m_ignore_count;      // Number of times to ignore this watchpoint
217   std::string m_decl_str;       // Declaration information, if any.
218   std::string m_watch_spec_str; // Spec for the watchpoint.
219   lldb::ValueObjectSP m_old_value_sp;
220   lldb::ValueObjectSP m_new_value_sp;
221   CompilerType m_type;
222   Status m_error; // An error object describing errors associated with this
223                   // watchpoint.
224   WatchpointOptions
225       m_options; // Settable watchpoint options, which is a delegate to handle
226                  // the callback machinery.
227   bool m_being_created;
228 
229   std::unique_ptr<UserExpression> m_condition_up; // The condition to test.
230 
231   void SetID(lldb::watch_id_t id) { m_id = id; }
232 
233   void SendWatchpointChangedEvent(lldb::WatchpointEventType eventKind);
234 
235   void SendWatchpointChangedEvent(WatchpointEventData *data);
236 
237   Watchpoint(const Watchpoint &) = delete;
238   const Watchpoint &operator=(const Watchpoint &) = delete;
239 };
240 
241 } // namespace lldb_private
242 
243 #endif // LLDB_BREAKPOINT_WATCHPOINT_H
244