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