RegisterContextFreeBSDKernelCore_i386.cpp

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//===----------------------------------------------------------------------===//
//
// 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 "RegisterContextFreeBSDKernelCore_i386.h"
 
#include "lldb/Target/Process.h"
#include "lldb/Target/Thread.h"
#include "lldb/Utility/RegisterValue.h"
#include "llvm/Support/Endian.h"
 
#if defined(__FreeBSD__) && defined(__i386__)
#include <machine/pcb.h>
#endif
 
using namespace lldb;
using namespace lldb_private;
 
RegisterContextFreeBSDKernelCore_i386::RegisterContextFreeBSDKernelCore_i386(
    Thread &thread, RegisterInfoInterface *register_info, lldb::addr_t pcb_addr)
    : RegisterContextPOSIX_x86(thread, 0, register_info), m_pcb_addr(pcb_addr) {
}
 
bool RegisterContextFreeBSDKernelCore_i386::ReadGPR() { return true; }
 
bool RegisterContextFreeBSDKernelCore_i386::ReadFPR() { return true; }
 
bool RegisterContextFreeBSDKernelCore_i386::WriteGPR() {
  assert(0);
  return false;
}
 
bool RegisterContextFreeBSDKernelCore_i386::WriteFPR() {
  assert(0);
  return false;
}
 
bool RegisterContextFreeBSDKernelCore_i386::ReadRegister(
    const RegisterInfo *reg_info, RegisterValue &value) {
  if (m_pcb_addr == LLDB_INVALID_ADDRESS)
    return false;
 
  // https://cgit.freebsd.org/src/tree/sys/i386/include/pcb.h
  struct {
    llvm::support::ulittle32_t edi;
    llvm::support::ulittle32_t esi;
    llvm::support::ulittle32_t ebp;
    llvm::support::ulittle32_t esp;
    llvm::support::ulittle32_t ebx;
    llvm::support::ulittle32_t eip;
  } pcb;
 
#if defined(__FreeBSD__) && defined(__i386__)
  static_assert(offsetof(struct pcb, pcb_edi) == offsetof(decltype(pcb), edi));
  static_assert(offsetof(struct pcb, pcb_esi) == offsetof(decltype(pcb), esi));
  static_assert(offsetof(struct pcb, pcb_ebp) == offsetof(decltype(pcb), ebp));
  static_assert(offsetof(struct pcb, pcb_esp) == offsetof(decltype(pcb), esp));
  static_assert(offsetof(struct pcb, pcb_ebx) == offsetof(decltype(pcb), ebx));
  static_assert(offsetof(struct pcb, pcb_eip) == offsetof(decltype(pcb), eip));
#endif
 
  Status error;
  size_t rd =
      m_thread.GetProcess()->ReadMemory(m_pcb_addr, &pcb, sizeof(pcb), error);
  if (rd != sizeof(pcb))
    return false;
 
  uint32_t reg = reg_info->kinds[lldb::eRegisterKindLLDB];
  switch (reg) {
#define REG(x)                                                                 \
  case lldb_##x##_i386:                                                        \
    value = pcb.x;                                                             \
    break;
 
    REG(edi);
    REG(esi);
    REG(ebp);
    REG(esp);
    REG(eip);
 
#undef REG
 
  default:
    return false;
  }
 
  return true;
}
 
bool RegisterContextFreeBSDKernelCore_i386::WriteRegister(
    const RegisterInfo *reg_info, const RegisterValue &value) {
  return false;
}