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      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 #include <vector>
     14 
     15 #include "lldb/lldb-public.h"
     16 #include "lldb/Symbol/FuncUnwinders.h"
     17 #include "lldb/Symbol/UnwindPlan.h"
     18 #include "lldb/Target/RegisterContext.h"
     19 #include "lldb/Target/Unwind.h"
     20 
     21 namespace lldb_private {
     22 
     23 class RegisterContextLLDB;
     24 
     25 class UnwindLLDB : public lldb_private::Unwind
     26 {
     27 public:
     28     UnwindLLDB (lldb_private::Thread &thread);
     29 
     30     virtual
     31     ~UnwindLLDB() { }
     32 
     33     enum RegisterSearchResult
     34     {
     35         eRegisterFound = 0,
     36         eRegisterNotFound,
     37         eRegisterIsVolatile
     38     };
     39 
     40 protected:
     41     friend class lldb_private::RegisterContextLLDB;
     42 
     43     struct RegisterLocation {
     44         enum RegisterLocationTypes
     45         {
     46             eRegisterNotSaved = 0,              // register was not preserved by callee.  If volatile reg, is unavailable
     47             eRegisterSavedAtMemoryLocation,     // register is saved at a specific word of target mem (target_memory_location)
     48             eRegisterInRegister,                // register is available in a (possible other) register (register_number)
     49             eRegisterSavedAtHostMemoryLocation, // register is saved at a word in lldb's address space
     50             eRegisterValueInferred              // register val was computed (and is in inferred_value)
     51         };
     52         int type;
     53         union
     54         {
     55             lldb::addr_t target_memory_location;
     56             uint32_t     register_number;       // in eRegisterKindLLDB register numbering system
     57             void*        host_memory_location;
     58             uint64_t     inferred_value;        // eRegisterValueInferred - e.g. stack pointer == cfa + offset
     59         } location;
     60     };
     61 
     62     void
     63     DoClear()
     64     {
     65         m_frames.clear();
     66         m_unwind_complete = false;
     67     }
     68 
     69     virtual uint32_t
     70     DoGetFrameCount();
     71 
     72     bool
     73     DoGetFrameInfoAtIndex (uint32_t frame_idx,
     74                          lldb::addr_t& cfa,
     75                          lldb::addr_t& start_pc);
     76 
     77     lldb::RegisterContextSP
     78     DoCreateRegisterContextForFrame (lldb_private::StackFrame *frame);
     79 
     80     typedef std::shared_ptr<RegisterContextLLDB> RegisterContextLLDBSP;
     81 
     82     // Needed to retrieve the "next" frame (e.g. frame 2 needs to retrieve frame 1's RegisterContextLLDB)
     83     // The RegisterContext for frame_num must already exist or this returns an empty shared pointer.
     84     RegisterContextLLDBSP
     85     GetRegisterContextForFrameNum (uint32_t frame_num);
     86 
     87     // Iterate over the RegisterContextLLDB's in our m_frames vector, look for the first one that
     88     // has a saved location for this reg.
     89     bool
     90     SearchForSavedLocationForRegister (uint32_t lldb_regnum, lldb_private::UnwindLLDB::RegisterLocation &regloc, uint32_t starting_frame_num, bool pc_register);
     91 
     92 
     93 private:
     94 
     95     struct Cursor
     96     {
     97         lldb::addr_t start_pc;  // The start address of the function/symbol for this frame - current pc if unknown
     98         lldb::addr_t cfa;       // The canonical frame address for this stack frame
     99         lldb_private::SymbolContext sctx;  // A symbol context we'll contribute to & provide to the StackFrame creation
    100         RegisterContextLLDBSP reg_ctx_lldb_sp; // These are all RegisterContextLLDB's
    101 
    102         Cursor () : start_pc (LLDB_INVALID_ADDRESS), cfa (LLDB_INVALID_ADDRESS), sctx(), reg_ctx_lldb_sp() { }
    103     private:
    104         DISALLOW_COPY_AND_ASSIGN (Cursor);
    105     };
    106 
    107     typedef std::shared_ptr<Cursor> CursorSP;
    108     std::vector<CursorSP> m_frames;
    109     bool m_unwind_complete; // If this is true, we've enumerated all the frames in the stack, and m_frames.size() is the
    110                             // number of frames, etc.  Otherwise we've only gone as far as directly asked, and m_frames.size()
    111                             // is how far we've currently gone.
    112 
    113 
    114     bool AddOneMoreFrame (ABI *abi);
    115     bool AddFirstFrame ();
    116 
    117     //------------------------------------------------------------------
    118     // For UnwindLLDB only
    119     //------------------------------------------------------------------
    120     DISALLOW_COPY_AND_ASSIGN (UnwindLLDB);
    121 };
    122 
    123 }   // namespace lldb_private
    124 
    125 #endif  // lldb_UnwindLLDB_h_
    126