1//===-- UnwindLLDB.h --------------------------------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef lldb_UnwindLLDB_h_
11#define lldb_UnwindLLDB_h_
12
13// C Includes
14// C++ Includes
15#include <vector>
16
17// Other libraries and framework includes
18// Project includes
19#include "lldb/lldb-public.h"
20#include "lldb/Core/ConstString.h"
21#include "lldb/Symbol/FuncUnwinders.h"
22#include "lldb/Symbol/UnwindPlan.h"
23#include "lldb/Target/RegisterContext.h"
24#include "lldb/Target/Unwind.h"
25
26namespace lldb_private {
27
28class RegisterContextLLDB;
29
30class UnwindLLDB : public lldb_private::Unwind
31{
32public:
33    UnwindLLDB (lldb_private::Thread &thread);
34
35    ~UnwindLLDB() override = default;
36
37    enum RegisterSearchResult
38    {
39        eRegisterFound = 0,
40        eRegisterNotFound,
41        eRegisterIsVolatile
42    };
43
44protected:
45    friend class lldb_private::RegisterContextLLDB;
46
47    struct RegisterLocation {
48        enum RegisterLocationTypes
49        {
50            eRegisterNotSaved = 0,              // register was not preserved by callee.  If volatile reg, is unavailable
51            eRegisterSavedAtMemoryLocation,     // register is saved at a specific word of target mem (target_memory_location)
52            eRegisterInRegister,                // register is available in a (possible other) register (register_number)
53            eRegisterSavedAtHostMemoryLocation, // register is saved at a word in lldb's address space
54            eRegisterValueInferred,             // register val was computed (and is in inferred_value)
55            eRegisterInLiveRegisterContext      // register value is in a live (stack frame #0) register
56        };
57        int type;
58        union
59        {
60            lldb::addr_t target_memory_location;
61            uint32_t     register_number;       // in eRegisterKindLLDB register numbering system
62            void*        host_memory_location;
63            uint64_t     inferred_value;        // eRegisterValueInferred - e.g. stack pointer == cfa + offset
64        } location;
65    };
66
67    void
68    DoClear() override
69    {
70        m_frames.clear();
71        m_candidate_frame.reset();
72        m_unwind_complete = false;
73    }
74
75    uint32_t
76    DoGetFrameCount() override;
77
78    bool
79    DoGetFrameInfoAtIndex(uint32_t frame_idx,
80                          lldb::addr_t& cfa,
81                          lldb::addr_t& start_pc) override;
82
83    lldb::RegisterContextSP
84    DoCreateRegisterContextForFrame(lldb_private::StackFrame *frame) override;
85
86    typedef std::shared_ptr<RegisterContextLLDB> RegisterContextLLDBSP;
87
88    // Needed to retrieve the "next" frame (e.g. frame 2 needs to retrieve frame 1's RegisterContextLLDB)
89    // The RegisterContext for frame_num must already exist or this returns an empty shared pointer.
90    RegisterContextLLDBSP
91    GetRegisterContextForFrameNum (uint32_t frame_num);
92
93    // Iterate over the RegisterContextLLDB's in our m_frames vector, look for the first one that
94    // has a saved location for this reg.
95    bool
96    SearchForSavedLocationForRegister (uint32_t lldb_regnum, lldb_private::UnwindLLDB::RegisterLocation &regloc, uint32_t starting_frame_num, bool pc_register);
97
98
99    //------------------------------------------------------------------
100    /// Provide the list of user-specified trap handler functions
101    ///
102    /// The Platform is one source of trap handler function names; that
103    /// may be augmented via a setting.  The setting needs to be converted
104    /// into an array of ConstStrings before it can be used - we only want
105    /// to do that once per thread so it's here in the UnwindLLDB object.
106    ///
107    /// @return
108    ///     Vector of ConstStrings of trap handler function names.  May be
109    ///     empty.
110    //------------------------------------------------------------------
111    const std::vector<ConstString> &
112    GetUserSpecifiedTrapHandlerFunctionNames ()
113    {
114        return m_user_supplied_trap_handler_functions;
115    }
116
117private:
118    struct Cursor
119    {
120        lldb::addr_t start_pc;  // The start address of the function/symbol for this frame - current pc if unknown
121        lldb::addr_t cfa;       // The canonical frame address for this stack frame
122        lldb_private::SymbolContext sctx;  // A symbol context we'll contribute to & provide to the StackFrame creation
123        RegisterContextLLDBSP reg_ctx_lldb_sp; // These are all RegisterContextLLDB's
124
125        Cursor () : start_pc (LLDB_INVALID_ADDRESS), cfa (LLDB_INVALID_ADDRESS), sctx(), reg_ctx_lldb_sp() { }
126    private:
127        DISALLOW_COPY_AND_ASSIGN (Cursor);
128    };
129
130    typedef std::shared_ptr<Cursor> CursorSP;
131    std::vector<CursorSP> m_frames;
132    CursorSP m_candidate_frame;
133    bool m_unwind_complete; // If this is true, we've enumerated all the frames in the stack, and m_frames.size() is the
134                            // number of frames, etc.  Otherwise we've only gone as far as directly asked, and m_frames.size()
135                            // is how far we've currently gone.
136
137    std::vector<ConstString> m_user_supplied_trap_handler_functions;
138
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    //-----------------------------------------------------------------
145    void
146    UpdateUnwindPlanForFirstFrameIfInvalid (ABI* abi);
147
148    CursorSP
149    GetOneMoreFrame (ABI* abi);
150
151    bool
152    AddOneMoreFrame (ABI *abi);
153
154    bool
155    AddFirstFrame ();
156
157    //------------------------------------------------------------------
158    // For UnwindLLDB only
159    //------------------------------------------------------------------
160    DISALLOW_COPY_AND_ASSIGN (UnwindLLDB);
161};
162
163} // namespace lldb_private
164
165#endif // lldb_UnwindLLDB_h_
166