Coverage Report

Created: 2022-01-22 13:19

/Users/buildslave/jenkins/workspace/coverage/llvm-project/lldb/include/lldb/Target/UnwindLLDB.h
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//===-- UnwindLLDB.h --------------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLDB_TARGET_UNWINDLLDB_H
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#define LLDB_TARGET_UNWINDLLDB_H
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#include <vector>
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#include "lldb/Symbol/FuncUnwinders.h"
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#include "lldb/Symbol/SymbolContext.h"
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#include "lldb/Symbol/UnwindPlan.h"
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#include "lldb/Target/RegisterContext.h"
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#include "lldb/Target/Unwind.h"
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#include "lldb/Utility/ConstString.h"
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#include "lldb/lldb-public.h"
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namespace lldb_private {
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class RegisterContextUnwind;
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class UnwindLLDB : public lldb_private::Unwind {
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public:
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  UnwindLLDB(lldb_private::Thread &thread);
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  ~UnwindLLDB() override = default;
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  enum RegisterSearchResult {
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    eRegisterFound = 0,
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    eRegisterNotFound,
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    eRegisterIsVolatile
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  };
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protected:
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  friend class lldb_private::RegisterContextUnwind;
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  struct RegisterLocation {
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    enum RegisterLocationTypes {
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      eRegisterNotSaved = 0, // register was not preserved by callee.  If
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                             // volatile reg, is unavailable
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      eRegisterSavedAtMemoryLocation, // register is saved at a specific word of
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                                      // target mem (target_memory_location)
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      eRegisterInRegister, // register is available in a (possible other)
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                           // register (register_number)
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      eRegisterSavedAtHostMemoryLocation, // register is saved at a word in
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                                          // lldb's address space
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      eRegisterValueInferred,        // register val was computed (and is in
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                                     // inferred_value)
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      eRegisterInLiveRegisterContext // register value is in a live (stack frame
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                                     // #0) register
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    };
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    int type;
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    union {
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      lldb::addr_t target_memory_location;
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      uint32_t
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          register_number; // in eRegisterKindLLDB register numbering system
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      void *host_memory_location;
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      uint64_t inferred_value; // eRegisterValueInferred - e.g. stack pointer ==
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                               // cfa + offset
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    } location;
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  };
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  void DoClear() override {
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    m_frames.clear();
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    m_candidate_frame.reset();
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    m_unwind_complete = false;
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  }
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  uint32_t DoGetFrameCount() override;
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  bool DoGetFrameInfoAtIndex(uint32_t frame_idx, lldb::addr_t &cfa,
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                             lldb::addr_t &start_pc,
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                             bool &behaves_like_zeroth_frame) override;
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  lldb::RegisterContextSP
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  DoCreateRegisterContextForFrame(lldb_private::StackFrame *frame) override;
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  typedef std::shared_ptr<RegisterContextUnwind> RegisterContextLLDBSP;
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  // Needed to retrieve the "next" frame (e.g. frame 2 needs to retrieve frame
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  // 1's RegisterContextUnwind)
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  // The RegisterContext for frame_num must already exist or this returns an
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  // empty shared pointer.
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  RegisterContextLLDBSP GetRegisterContextForFrameNum(uint32_t frame_num);
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  // Iterate over the RegisterContextUnwind's in our m_frames vector, look for
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  // the first one that has a saved location for this reg.
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  bool SearchForSavedLocationForRegister(
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      uint32_t lldb_regnum, lldb_private::UnwindLLDB::RegisterLocation &regloc,
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      uint32_t starting_frame_num, bool pc_register);
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  /// Provide the list of user-specified trap handler functions
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  ///
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  /// The Platform is one source of trap handler function names; that
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  /// may be augmented via a setting.  The setting needs to be converted
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  /// into an array of ConstStrings before it can be used - we only want
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  /// to do that once per thread so it's here in the UnwindLLDB object.
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  ///
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  /// \return
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  ///     Vector of ConstStrings of trap handler function names.  May be
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  ///     empty.
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  const std::vector<ConstString> &GetUserSpecifiedTrapHandlerFunctionNames() {
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    return m_user_supplied_trap_handler_functions;
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  }
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private:
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  struct Cursor {
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    lldb::addr_t start_pc =
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        LLDB_INVALID_ADDRESS; // The start address of the function/symbol for
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                              // this frame - current pc if unknown
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    lldb::addr_t cfa = LLDB_INVALID_ADDRESS; // The canonical frame address for
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                                             // this stack frame
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    lldb_private::SymbolContext sctx; // A symbol context we'll contribute to &
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                                      // provide to the StackFrame creation
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    RegisterContextLLDBSP
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        reg_ctx_lldb_sp; // These are all RegisterContextUnwind's
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    Cursor() {}
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  private:
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    Cursor(const Cursor &) = delete;
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    const Cursor &operator=(const Cursor &) = delete;
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  };
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  typedef std::shared_ptr<Cursor> CursorSP;
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  std::vector<CursorSP> m_frames;
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  CursorSP m_candidate_frame;
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  bool m_unwind_complete; // If this is true, we've enumerated all the frames in
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                          // the stack, and m_frames.size() is the
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  // number of frames, etc.  Otherwise we've only gone as far as directly asked,
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  // and m_frames.size()
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  // is how far we've currently gone.
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  std::vector<ConstString> m_user_supplied_trap_handler_functions;
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  // Check if Full UnwindPlan of First frame is valid or not.
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  // If not then try Fallback UnwindPlan of the frame. If Fallback
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  // UnwindPlan succeeds then update the Full UnwindPlan with the
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  // Fallback UnwindPlan.
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  void UpdateUnwindPlanForFirstFrameIfInvalid(ABI *abi);
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  CursorSP GetOneMoreFrame(ABI *abi);
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  bool AddOneMoreFrame(ABI *abi);
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  bool AddFirstFrame();
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  // For UnwindLLDB only
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  UnwindLLDB(const UnwindLLDB &) = delete;
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  const UnwindLLDB &operator=(const UnwindLLDB &) = delete;
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};
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} // namespace lldb_private
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#endif // LLDB_TARGET_UNWINDLLDB_H