1//===-- BreakpointSite.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 liblldb_BreakpointSite_h_
10#define liblldb_BreakpointSite_h_
11
12
13#include <list>
14#include <mutex>
15
16
17#include "lldb/Breakpoint/BreakpointLocationCollection.h"
18#include "lldb/Breakpoint/StoppointLocation.h"
19#include "lldb/Utility/UserID.h"
20#include "lldb/lldb-forward.h"
21
22namespace lldb_private {
23
24/// \class BreakpointSite BreakpointSite.h "lldb/Breakpoint/BreakpointSite.h"
25/// Class that manages the actual breakpoint that will be inserted into the
26/// running program.
27///
28/// The BreakpointSite class handles the physical breakpoint that is actually
29/// inserted in the target program.  As such, it is also the one that  gets
30/// hit, when the program stops. It keeps a list of all BreakpointLocations
31/// that share this physical site. When the breakpoint is hit, all the
32/// locations are informed by the breakpoint site. Breakpoint sites are owned
33/// by the process.
34
35class BreakpointSite : public std::enable_shared_from_this<BreakpointSite>,
36                       public StoppointLocation {
37public:
38  enum Type {
39    eSoftware, // Breakpoint opcode has been written to memory and
40               // m_saved_opcode
41               // and m_trap_opcode contain the saved and written opcode.
42    eHardware, // Breakpoint site is set as a hardware breakpoint
43    eExternal  // Breakpoint site is managed by an external debug nub or
44               // debug interface where memory reads transparently will not
45               // display any breakpoint opcodes.
46  };
47
48  ~BreakpointSite() override;
49
50  // This section manages the breakpoint traps
51
52  /// Returns the Opcode Bytes for this breakpoint
53  uint8_t *GetTrapOpcodeBytes();
54
55  /// Returns the Opcode Bytes for this breakpoint - const version
56  const uint8_t *GetTrapOpcodeBytes() const;
57
58  /// Get the size of the trap opcode for this address
59  size_t GetTrapOpcodeMaxByteSize() const;
60
61  /// Sets the trap opcode
62  bool SetTrapOpcode(const uint8_t *trap_opcode, uint32_t trap_opcode_size);
63
64  /// Gets the original instruction bytes that were overwritten by the trap
65  uint8_t *GetSavedOpcodeBytes();
66
67  /// Gets the original instruction bytes that were overwritten by the trap
68  /// const version
69  const uint8_t *GetSavedOpcodeBytes() const;
70
71  /// Says whether \a addr and size \a size intersects with the address \a
72  /// intersect_addr
73  bool IntersectsRange(lldb::addr_t addr, size_t size,
74                       lldb::addr_t *intersect_addr, size_t *intersect_size,
75                       size_t *opcode_offset) const;
76
77  /// Tells whether the current breakpoint site is enabled or not
78  ///
79  /// This is a low-level enable bit for the breakpoint sites.  If a
80  /// breakpoint site has no enabled owners, it should just get removed.  This
81  /// enable/disable is for the low-level target code to enable and disable
82  /// breakpoint sites when single stepping, etc.
83  bool IsEnabled() const;
84
85  /// Sets whether the current breakpoint site is enabled or not
86  ///
87  /// \param[in] enabled
88  ///    \b true if the breakpoint is enabled, \b false otherwise.
89  void SetEnabled(bool enabled);
90
91  /// Enquires of the breakpoint locations that produced this breakpoint site
92  /// whether we should stop at this location.
93  ///
94  /// \param[in] context
95  ///    This contains the information about this stop.
96  ///
97  /// \return
98  ///    \b true if we should stop, \b false otherwise.
99  bool ShouldStop(StoppointCallbackContext *context) override;
100
101  /// Standard Dump method
102  void Dump(Stream *s) const override;
103
104  /// The "Owners" are the breakpoint locations that share this breakpoint
105  /// site. The method adds the \a owner to this breakpoint site's owner list.
106  ///
107  /// \param[in] owner
108  ///    \a owner is the Breakpoint Location to add.
109  void AddOwner(const lldb::BreakpointLocationSP &owner);
110
111  /// This method returns the number of breakpoint locations currently located
112  /// at this breakpoint site.
113  ///
114  /// \return
115  ///    The number of owners.
116  size_t GetNumberOfOwners();
117
118  /// This method returns the breakpoint location at index \a index located at
119  /// this breakpoint site.  The owners are listed ordinally from 0 to
120  /// GetNumberOfOwners() - 1 so you can use this method to iterate over the
121  /// owners
122  ///
123  /// \param[in] idx
124  ///     The index in the list of owners for which you wish the owner location.
125  ///
126  /// \return
127  ///    A shared pointer to the breakpoint location at that index.
128  lldb::BreakpointLocationSP GetOwnerAtIndex(size_t idx);
129
130  /// This method copies the breakpoint site's owners into a new collection.
131  /// It does this while the owners mutex is locked.
132  ///
133  /// \param[out] out_collection
134  ///    The BreakpointLocationCollection into which to put the owners
135  ///    of this breakpoint site.
136  ///
137  /// \return
138  ///    The number of elements copied into out_collection.
139  size_t CopyOwnersList(BreakpointLocationCollection &out_collection);
140
141  /// Check whether the owners of this breakpoint site have any thread
142  /// specifiers, and if yes, is \a thread contained in any of these
143  /// specifiers.
144  ///
145  /// \param[in] thread
146  ///     The thread against which to test.
147  ///
148  /// return
149  ///     \b true if the collection contains at least one location that
150  ///     would be valid for this thread, false otherwise.
151  bool ValidForThisThread(Thread *thread);
152
153  /// Print a description of this breakpoint site to the stream \a s.
154  /// GetDescription tells you about the breakpoint site's owners. Use
155  /// BreakpointSite::Dump(Stream *) to get information about the breakpoint
156  /// site itself.
157  ///
158  /// \param[in] s
159  ///     The stream to which to print the description.
160  ///
161  /// \param[in] level
162  ///     The description level that indicates the detail level to
163  ///     provide.
164  ///
165  /// \see lldb::DescriptionLevel
166  void GetDescription(Stream *s, lldb::DescriptionLevel level);
167
168  /// Tell whether a breakpoint has a location at this site.
169  ///
170  /// \param[in] bp_id
171  ///     The breakpoint id to query.
172  ///
173  /// \result
174  ///     \b true if bp_id has a location that is at this site,
175  ///     \b false otherwise.
176  bool IsBreakpointAtThisSite(lldb::break_id_t bp_id);
177
178  /// Tell whether ALL the breakpoints in the location collection are
179  /// internal.
180  ///
181  /// \result
182  ///     \b true if all breakpoint locations are owned by internal breakpoints,
183  ///     \b false otherwise.
184  bool IsInternal() const;
185
186  BreakpointSite::Type GetType() const { return m_type; }
187
188  void SetType(BreakpointSite::Type type) { m_type = type; }
189
190private:
191  friend class Process;
192  friend class BreakpointLocation;
193  // The StopInfoBreakpoint knows when it is processing a hit for a thread for
194  // a site, so let it be the one to manage setting the location hit count once
195  // and only once.
196  friend class StopInfoBreakpoint;
197
198  void BumpHitCounts();
199
200  /// The method removes the owner at \a break_loc_id from this breakpoint
201  /// list.
202  size_t RemoveOwner(lldb::break_id_t break_id, lldb::break_id_t break_loc_id);
203
204  BreakpointSite::Type m_type; ///< The type of this breakpoint site.
205  uint8_t m_saved_opcode[8]; ///< The saved opcode bytes if this breakpoint site
206                             ///uses trap opcodes.
207  uint8_t m_trap_opcode[8];  ///< The opcode that was used to create the
208                             ///breakpoint if it is a software breakpoint site.
209  bool
210      m_enabled; ///< Boolean indicating if this breakpoint site enabled or not.
211
212  // Consider adding an optimization where if there is only one owner, we don't
213  // store a list.  The usual case will be only one owner...
214  BreakpointLocationCollection m_owners; ///< This has the BreakpointLocations
215                                         ///that share this breakpoint site.
216  std::recursive_mutex
217      m_owners_mutex; ///< This mutex protects the owners collection.
218
219  static lldb::break_id_t GetNextID();
220
221  // Only the Process can create breakpoint sites in
222  // Process::CreateBreakpointSite (lldb::BreakpointLocationSP &, bool).
223  BreakpointSite(BreakpointSiteList *list,
224                 const lldb::BreakpointLocationSP &owner, lldb::addr_t m_addr,
225                 bool use_hardware);
226
227  DISALLOW_COPY_AND_ASSIGN(BreakpointSite);
228};
229
230} // namespace lldb_private
231
232#endif // liblldb_BreakpointSite_h_
233