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 22 namespace lldb_private { 23 24 class RegisterContextUnwind; 25 26 class UnwindLLDB : public lldb_private::Unwind { 27 public: 28 UnwindLLDB(lldb_private::Thread &thread); 29 30 ~UnwindLLDB() override = default; 31 32 enum RegisterSearchResult { 33 eRegisterFound = 0, 34 eRegisterNotFound, 35 eRegisterIsVolatile 36 }; 37 38 protected: 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 DoClear()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 ®loc, 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. GetUserSpecifiedTrapHandlerFunctionNames()106 const std::vector<ConstString> &GetUserSpecifiedTrapHandlerFunctionNames() { 107 return m_user_supplied_trap_handler_functions; 108 } 109 110 private: 111 struct Cursor { 112 lldb::addr_t start_pc; // The start address of the function/symbol for this 113 // frame - current pc if unknown 114 lldb::addr_t cfa; // The canonical frame address for this stack frame 115 lldb_private::SymbolContext sctx; // A symbol context we'll contribute to & 116 // provide to the StackFrame creation 117 RegisterContextLLDBSP 118 reg_ctx_lldb_sp; // These are all RegisterContextUnwind's 119 CursorCursor120 Cursor() 121 : start_pc(LLDB_INVALID_ADDRESS), cfa(LLDB_INVALID_ADDRESS), sctx(), 122 reg_ctx_lldb_sp() {} 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