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//===-- NativeProcessSoftwareSingleStep.cpp -------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "NativeProcessSoftwareSingleStep.h"
#include "lldb/Core/EmulateInstruction.h"
#include "lldb/Host/common/NativeRegisterContext.h"
#include "lldb/Utility/RegisterValue.h"
#include <unordered_map>
using namespace lldb;
using namespace lldb_private;
namespace {
struct EmulatorBaton {
NativeProcessProtocol &m_process;
NativeRegisterContext &m_reg_context;
// eRegisterKindDWARF -> RegsiterValue
std::unordered_map<uint32_t, RegisterValue> m_register_values;
EmulatorBaton(NativeProcessProtocol &process,
NativeRegisterContext ®_context)
: m_process(process), m_reg_context(reg_context) {}
};
} // anonymous namespace
static size_t ReadMemoryCallback(EmulateInstruction *instruction, void *baton,
const EmulateInstruction::Context &context,
lldb::addr_t addr, void *dst, size_t length) {
EmulatorBaton *emulator_baton = static_cast<EmulatorBaton *>(baton);
size_t bytes_read;
emulator_baton->m_process.ReadMemory(addr, dst, length, bytes_read);
return bytes_read;
}
static bool ReadRegisterCallback(EmulateInstruction *instruction, void *baton,
const RegisterInfo *reg_info,
RegisterValue ®_value) {
EmulatorBaton *emulator_baton = static_cast<EmulatorBaton *>(baton);
auto it = emulator_baton->m_register_values.find(
reg_info->kinds[eRegisterKindDWARF]);
if (it != emulator_baton->m_register_values.end()) {
reg_value = it->second;
return true;
}
// The emulator only fill in the dwarf regsiter numbers (and in some case the
// generic register numbers). Get the full register info from the register
// context based on the dwarf register numbers.
const RegisterInfo *full_reg_info =
emulator_baton->m_reg_context.GetRegisterInfo(
eRegisterKindDWARF, reg_info->kinds[eRegisterKindDWARF]);
Status error =
emulator_baton->m_reg_context.ReadRegister(full_reg_info, reg_value);
if (error.Success())
return true;
return false;
}
static bool WriteRegisterCallback(EmulateInstruction *instruction, void *baton,
const EmulateInstruction::Context &context,
const RegisterInfo *reg_info,
const RegisterValue ®_value) {
EmulatorBaton *emulator_baton = static_cast<EmulatorBaton *>(baton);
emulator_baton->m_register_values[reg_info->kinds[eRegisterKindDWARF]] =
reg_value;
return true;
}
static size_t WriteMemoryCallback(EmulateInstruction *instruction, void *baton,
const EmulateInstruction::Context &context,
lldb::addr_t addr, const void *dst,
size_t length) {
return length;
}
static Status SetSoftwareBreakpoint(lldb::addr_t bp_addr, unsigned bp_size,
NativeProcessProtocol &process) {
Status error;
error = process.SetBreakpoint(bp_addr, bp_size, /*hardware=*/false);
// If setting the breakpoint fails because pc is out of the address
// space, ignore it and let the debugee segfault.
if (error.GetError() == EIO || error.GetError() == EFAULT)
return Status();
if (error.Fail())
return error;
return Status();
}
Status NativeProcessSoftwareSingleStep::SetupSoftwareSingleStepping(
NativeThreadProtocol &thread) {
Status error;
NativeProcessProtocol &process = thread.GetProcess();
NativeRegisterContext ®ister_context = thread.GetRegisterContext();
const ArchSpec &arch = process.GetArchitecture();
std::unique_ptr<EmulateInstruction> emulator_up(
EmulateInstruction::FindPlugin(arch, eInstructionTypePCModifying,
nullptr));
if (emulator_up == nullptr)
return Status::FromErrorString("Instruction emulator not found!");
EmulatorBaton baton(process, register_context);
emulator_up->SetBaton(&baton);
emulator_up->SetReadMemCallback(&ReadMemoryCallback);
emulator_up->SetReadRegCallback(&ReadRegisterCallback);
emulator_up->SetWriteMemCallback(&WriteMemoryCallback);
emulator_up->SetWriteRegCallback(&WriteRegisterCallback);
auto bp_locaions_predictor =
EmulateInstruction::CreateBreakpointLocationPredictor(
std::move(emulator_up));
auto bp_locations = bp_locaions_predictor->GetBreakpointLocations(error);
if (error.Fail())
return error;
for (auto &&bp_addr : bp_locations) {
auto bp_size = bp_locaions_predictor->GetBreakpointSize(bp_addr);
if (auto err = bp_size.takeError())
return Status(toString(std::move(err)));
error = SetSoftwareBreakpoint(bp_addr, *bp_size, process);
if (error.Fail())
return error;
}
m_threads_stepping_with_breakpoint.insert({thread.GetID(), bp_locations});
return error;
}
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