UnwindLLDB.h revision 360784 
1//===-- UnwindLLDB.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_UnwindLLDB_h_
10#define lldb_UnwindLLDB_h_
11
12#include <vector>
13
14#include "lldb/Symbol/FuncUnwinders.h"
15#include "lldb/Symbol/SymbolContext.h"
16#include "lldb/Symbol/UnwindPlan.h"
17#include "lldb/Target/RegisterContext.h"
18#include "lldb/Target/Unwind.h"
19#include "lldb/Utility/ConstString.h"
20#include "lldb/lldb-public.h"
21
22namespace lldb_private {
23
24class RegisterContextLLDB;
25
26class UnwindLLDB : public lldb_private::Unwind {
27public:
28  UnwindLLDB(lldb_private::Thread &thread);
29
30  ~UnwindLLDB() override = default;
31
32  enum RegisterSearchResult {
33    eRegisterFound = 0,
34    eRegisterNotFound,
35    eRegisterIsVolatile
36  };
37
38protected:
39  friend class lldb_private::RegisterContextLLDB;
40
41  struct RegisterLocation {
42    enum RegisterLocationTypes {
43      eRegisterNotSaved = 0, // register was not preserved by callee.  If
44                             // volatile reg, is unavailable
45      eRegisterSavedAtMemoryLocation, // register is saved at a specific word of
46                                      // target mem (target_memory_location)
47      eRegisterInRegister, // register is available in a (possible other)
48                           // register (register_number)
49      eRegisterSavedAtHostMemoryLocation, // register is saved at a word in
50                                          // lldb's address space
51      eRegisterValueInferred,        // register val was computed (and is in
52                                     // inferred_value)
53      eRegisterInLiveRegisterContext // register value is in a live (stack frame
54                                     // #0) register
55    };
56    int type;
57    union {
58      lldb::addr_t target_memory_location;
59      uint32_t
60          register_number; // in eRegisterKindLLDB register numbering system
61      void *host_memory_location;
62      uint64_t inferred_value; // eRegisterValueInferred - e.g. stack pointer ==
63                               // cfa + offset
64    } location;
65  };
66
67  void DoClear() override {
68    m_frames.clear();
69    m_candidate_frame.reset();
70    m_unwind_complete = false;
71  }
72
73  uint32_t DoGetFrameCount() override;
74
75  bool DoGetFrameInfoAtIndex(uint32_t frame_idx, lldb::addr_t &cfa,
76                             lldb::addr_t &start_pc,
77                             bool &behaves_like_zeroth_frame) override;
78
79  lldb::RegisterContextSP
80  DoCreateRegisterContextForFrame(lldb_private::StackFrame *frame) override;
81
82  typedef std::shared_ptr<RegisterContextLLDB> RegisterContextLLDBSP;
83
84  // Needed to retrieve the "next" frame (e.g. frame 2 needs to retrieve frame
85  // 1's RegisterContextLLDB)
86  // The RegisterContext for frame_num must already exist or this returns an
87  // empty shared pointer.
88  RegisterContextLLDBSP GetRegisterContextForFrameNum(uint32_t frame_num);
89
90  // Iterate over the RegisterContextLLDB's in our m_frames vector, look for the
91  // first one that
92  // has a saved location for this reg.
93  bool SearchForSavedLocationForRegister(
94      uint32_t lldb_regnum, lldb_private::UnwindLLDB::RegisterLocation &regloc,
95      uint32_t starting_frame_num, bool pc_register);
96
97  /// Provide the list of user-specified trap handler functions
98  ///
99  /// The Platform is one source of trap handler function names; that
100  /// may be augmented via a setting.  The setting needs to be converted
101  /// into an array of ConstStrings before it can be used - we only want
102  /// to do that once per thread so it's here in the UnwindLLDB object.
103  ///
104  /// \return
105  ///     Vector of ConstStrings of trap handler function names.  May be
106  ///     empty.
107  const std::vector<ConstString> &GetUserSpecifiedTrapHandlerFunctionNames() {
108    return m_user_supplied_trap_handler_functions;
109  }
110
111private:
112  struct Cursor {
113    lldb::addr_t start_pc; // The start address of the function/symbol for this
114                           // frame - current pc if unknown
115    lldb::addr_t cfa;      // The canonical frame address for this stack frame
116    lldb_private::SymbolContext sctx; // A symbol context we'll contribute to &
117                                      // provide to the StackFrame creation
118    RegisterContextLLDBSP
119        reg_ctx_lldb_sp; // These are all RegisterContextLLDB's
120
121    Cursor()
122        : start_pc(LLDB_INVALID_ADDRESS), cfa(LLDB_INVALID_ADDRESS), sctx(),
123          reg_ctx_lldb_sp() {}
124
125  private:
126    DISALLOW_COPY_AND_ASSIGN(Cursor);
127  };
128
129  typedef std::shared_ptr<Cursor> CursorSP;
130  std::vector<CursorSP> m_frames;
131  CursorSP m_candidate_frame;
132  bool m_unwind_complete; // If this is true, we've enumerated all the frames in
133                          // the stack, and m_frames.size() is the
134  // number of frames, etc.  Otherwise we've only gone as far as directly asked,
135  // and m_frames.size()
136  // is how far we've currently gone.
137
138  std::vector<ConstString> m_user_supplied_trap_handler_functions;
139
140  // Check if Full UnwindPlan of First frame is valid or not.
141  // If not then try Fallback UnwindPlan of the frame. If Fallback
142  // UnwindPlan succeeds then update the Full UnwindPlan with the
143  // Fallback UnwindPlan.
144  void UpdateUnwindPlanForFirstFrameIfInvalid(ABI *abi);
145
146  CursorSP GetOneMoreFrame(ABI *abi);
147
148  bool AddOneMoreFrame(ABI *abi);
149
150  bool AddFirstFrame();
151
152  // For UnwindLLDB only
153  DISALLOW_COPY_AND_ASSIGN(UnwindLLDB);
154};
155
156} // namespace lldb_private
157
158#endif // lldb_UnwindLLDB_h_
159