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_TARGET_UNWINDLLDB_H
10#define LLDB_TARGET_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 RegisterContextUnwind;
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::RegisterContextUnwind;
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<RegisterContextUnwind> RegisterContextLLDBSP;
83
84 // Needed to retrieve the "next" frame (e.g. frame 2 needs to retrieve frame
85 // 1's RegisterContextUnwind)
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 RegisterContextUnwind's in our m_frames vector, look for
91 // the first one that has a saved location for this reg.
92 bool SearchForSavedLocationForRegister(
93 uint32_t lldb_regnum, lldb_private::UnwindLLDB::RegisterLocation &regloc,
94 uint32_t starting_frame_num, bool pc_register);
95
96 /// Provide the list of user-specified trap handler functions
97 ///
98 /// The Platform is one source of trap handler function names; that
99 /// may be augmented via a setting. The setting needs to be converted
100 /// into an array of ConstStrings before it can be used - we only want
101 /// to do that once per thread so it's here in the UnwindLLDB object.
102 ///
103 /// \return
104 /// Vector of ConstStrings of trap handler function names. May be
105 /// empty.
106 const std::vector<ConstString> &GetUserSpecifiedTrapHandlerFunctionNames() {
107 return m_user_supplied_trap_handler_functions;
108 }
109
110private:
111 struct Cursor {
112 lldb::addr_t start_pc =
113 LLDB_INVALID_ADDRESS; // The start address of the function/symbol for
114 // this frame - current pc if unknown
115 lldb::addr_t cfa = LLDB_INVALID_ADDRESS; // The canonical frame address for
116 // this stack frame
117 lldb_private::SymbolContext sctx; // A symbol context we'll contribute to &
118 // provide to the StackFrame creation
119 RegisterContextLLDBSP
120 reg_ctx_lldb_sp; // These are all RegisterContextUnwind's
121
122 Cursor() = default;
123
124 private:
125 Cursor(const Cursor &) = delete;
126 const Cursor &operator=(const Cursor &) = delete;
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 UnwindLLDB(const UnwindLLDB &) = delete;
154 const UnwindLLDB &operator=(const UnwindLLDB &) = delete;
155};
156
157} // namespace lldb_private
158
159#endif // LLDB_TARGET_UNWINDLLDB_H
160

source code of lldb/include/lldb/Target/UnwindLLDB.h