1//===-- GDBRemoteRegisterContext.cpp --------------------------------------===//
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#include "GDBRemoteRegisterContext.h"
10
11#include "ProcessGDBRemote.h"
12#include "ProcessGDBRemoteLog.h"
13#include "ThreadGDBRemote.h"
14#include "Utility/ARM_DWARF_Registers.h"
15#include "Utility/ARM_ehframe_Registers.h"
16#include "lldb/Core/Architecture.h"
17#include "lldb/Target/ExecutionContext.h"
18#include "lldb/Target/Target.h"
19#include "lldb/Utility/DataBufferHeap.h"
20#include "lldb/Utility/DataExtractor.h"
21#include "lldb/Utility/RegisterValue.h"
22#include "lldb/Utility/Scalar.h"
23#include "lldb/Utility/StreamString.h"
24#include "lldb/Utility/StringExtractorGDBRemote.h"
25
26#include <memory>
27
28using namespace lldb;
29using namespace lldb_private;
30using namespace lldb_private::process_gdb_remote;
31
32// GDBRemoteRegisterContext constructor
33GDBRemoteRegisterContext::GDBRemoteRegisterContext(
34    ThreadGDBRemote &thread, uint32_t concrete_frame_idx,
35    GDBRemoteDynamicRegisterInfoSP reg_info_sp, bool read_all_at_once,
36    bool write_all_at_once)
37    : RegisterContext(thread, concrete_frame_idx),
38      m_reg_info_sp(std::move(reg_info_sp)), m_reg_valid(), m_reg_data(),
39      m_read_all_at_once(read_all_at_once),
40      m_write_all_at_once(write_all_at_once), m_gpacket_cached(false) {
41  // Resize our vector of bools to contain one bool for every register. We will
42  // use these boolean values to know when a register value is valid in
43  // m_reg_data.
44  m_reg_valid.resize(m_reg_info_sp->GetNumRegisters());
45
46  // Make a heap based buffer that is big enough to store all registers
47  DataBufferSP reg_data_sp(
48      new DataBufferHeap(m_reg_info_sp->GetRegisterDataByteSize(), 0));
49  m_reg_data.SetData(reg_data_sp);
50  m_reg_data.SetByteOrder(thread.GetProcess()->GetByteOrder());
51}
52
53// Destructor
54GDBRemoteRegisterContext::~GDBRemoteRegisterContext() = default;
55
56void GDBRemoteRegisterContext::InvalidateAllRegisters() {
57  SetAllRegisterValid(false);
58}
59
60void GDBRemoteRegisterContext::SetAllRegisterValid(bool b) {
61  m_gpacket_cached = b;
62  std::vector<bool>::iterator pos, end = m_reg_valid.end();
63  for (pos = m_reg_valid.begin(); pos != end; ++pos)
64    *pos = b;
65}
66
67size_t GDBRemoteRegisterContext::GetRegisterCount() {
68  return m_reg_info_sp->GetNumRegisters();
69}
70
71const RegisterInfo *
72GDBRemoteRegisterContext::GetRegisterInfoAtIndex(size_t reg) {
73  return m_reg_info_sp->GetRegisterInfoAtIndex(reg);
74}
75
76size_t GDBRemoteRegisterContext::GetRegisterSetCount() {
77  return m_reg_info_sp->GetNumRegisterSets();
78}
79
80const RegisterSet *GDBRemoteRegisterContext::GetRegisterSet(size_t reg_set) {
81  return m_reg_info_sp->GetRegisterSet(reg_set);
82}
83
84bool GDBRemoteRegisterContext::ReadRegister(const RegisterInfo *reg_info,
85                                            RegisterValue &value) {
86  // Read the register
87  if (ReadRegisterBytes(reg_info)) {
88    const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
89    if (m_reg_valid[reg] == false)
90      return false;
91    if (reg_info->value_regs &&
92        reg_info->value_regs[0] != LLDB_INVALID_REGNUM &&
93        reg_info->value_regs[1] != LLDB_INVALID_REGNUM) {
94      std::vector<char> combined_data;
95      uint32_t offset = 0;
96      for (int i = 0; reg_info->value_regs[i] != LLDB_INVALID_REGNUM; i++) {
97        const RegisterInfo *parent_reg = GetRegisterInfo(
98            eRegisterKindLLDB, reg_info->value_regs[i]);
99        if (!parent_reg)
100          return false;
101        combined_data.resize(offset + parent_reg->byte_size);
102        if (m_reg_data.CopyData(parent_reg->byte_offset, parent_reg->byte_size,
103                                combined_data.data() + offset) !=
104            parent_reg->byte_size)
105          return false;
106        offset += parent_reg->byte_size;
107      }
108
109      Status error;
110      return value.SetFromMemoryData(
111                 *reg_info, combined_data.data(), combined_data.size(),
112                 m_reg_data.GetByteOrder(), error) == combined_data.size();
113    } else {
114      const bool partial_data_ok = false;
115      Status error(value.SetValueFromData(
116          *reg_info, m_reg_data, reg_info->byte_offset, partial_data_ok));
117      return error.Success();
118    }
119  }
120  return false;
121}
122
123bool GDBRemoteRegisterContext::PrivateSetRegisterValue(
124    uint32_t reg, llvm::ArrayRef<uint8_t> data) {
125  const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg);
126  if (reg_info == nullptr)
127    return false;
128
129  // Invalidate if needed
130  InvalidateIfNeeded(false);
131
132  const size_t reg_byte_size = reg_info->byte_size;
133  memcpy(const_cast<uint8_t *>(
134             m_reg_data.PeekData(reg_info->byte_offset, reg_byte_size)),
135         data.data(), std::min(data.size(), reg_byte_size));
136  bool success = data.size() >= reg_byte_size;
137  if (success) {
138    SetRegisterIsValid(reg, true);
139  } else if (data.size() > 0) {
140    // Only set register is valid to false if we copied some bytes, else leave
141    // it as it was.
142    SetRegisterIsValid(reg, false);
143  }
144  return success;
145}
146
147bool GDBRemoteRegisterContext::PrivateSetRegisterValue(uint32_t reg,
148                                                       uint64_t new_reg_val) {
149  const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg);
150  if (reg_info == nullptr)
151    return false;
152
153  // Early in process startup, we can get a thread that has an invalid byte
154  // order because the process hasn't been completely set up yet (see the ctor
155  // where the byte order is setfrom the process).  If that's the case, we
156  // can't set the value here.
157  if (m_reg_data.GetByteOrder() == eByteOrderInvalid) {
158    return false;
159  }
160
161  // Invalidate if needed
162  InvalidateIfNeeded(false);
163
164  DataBufferSP buffer_sp(new DataBufferHeap(&new_reg_val, sizeof(new_reg_val)));
165  DataExtractor data(buffer_sp, endian::InlHostByteOrder(), sizeof(void *));
166
167  // If our register context and our register info disagree, which should never
168  // happen, don't overwrite past the end of the buffer.
169  if (m_reg_data.GetByteSize() < reg_info->byte_offset + reg_info->byte_size)
170    return false;
171
172  // Grab a pointer to where we are going to put this register
173  uint8_t *dst = const_cast<uint8_t *>(
174      m_reg_data.PeekData(reg_info->byte_offset, reg_info->byte_size));
175
176  if (dst == nullptr)
177    return false;
178
179  if (data.CopyByteOrderedData(0,                          // src offset
180                               reg_info->byte_size,        // src length
181                               dst,                        // dst
182                               reg_info->byte_size,        // dst length
183                               m_reg_data.GetByteOrder())) // dst byte order
184  {
185    SetRegisterIsValid(reg, true);
186    return true;
187  }
188  return false;
189}
190
191// Helper function for GDBRemoteRegisterContext::ReadRegisterBytes().
192bool GDBRemoteRegisterContext::GetPrimordialRegister(
193    const RegisterInfo *reg_info, GDBRemoteCommunicationClient &gdb_comm) {
194  const uint32_t lldb_reg = reg_info->kinds[eRegisterKindLLDB];
195  const uint32_t remote_reg = reg_info->kinds[eRegisterKindProcessPlugin];
196
197  if (DataBufferSP buffer_sp =
198          gdb_comm.ReadRegister(m_thread.GetProtocolID(), remote_reg))
199    return PrivateSetRegisterValue(
200        lldb_reg, llvm::ArrayRef<uint8_t>(buffer_sp->GetBytes(),
201                                          buffer_sp->GetByteSize()));
202  return false;
203}
204
205bool GDBRemoteRegisterContext::ReadRegisterBytes(const RegisterInfo *reg_info) {
206  ExecutionContext exe_ctx(CalculateThread());
207
208  Process *process = exe_ctx.GetProcessPtr();
209  Thread *thread = exe_ctx.GetThreadPtr();
210  if (process == nullptr || thread == nullptr)
211    return false;
212
213  GDBRemoteCommunicationClient &gdb_comm(
214      ((ProcessGDBRemote *)process)->GetGDBRemote());
215
216  InvalidateIfNeeded(false);
217
218  const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
219
220  if (!GetRegisterIsValid(reg)) {
221    if (m_read_all_at_once && !m_gpacket_cached) {
222      if (DataBufferSP buffer_sp =
223              gdb_comm.ReadAllRegisters(m_thread.GetProtocolID())) {
224        memcpy(const_cast<uint8_t *>(m_reg_data.GetDataStart()),
225               buffer_sp->GetBytes(),
226               std::min(buffer_sp->GetByteSize(), m_reg_data.GetByteSize()));
227        if (buffer_sp->GetByteSize() >= m_reg_data.GetByteSize()) {
228          SetAllRegisterValid(true);
229          return true;
230        } else if (buffer_sp->GetByteSize() > 0) {
231          for (auto x : llvm::enumerate(
232                   m_reg_info_sp->registers<
233                       DynamicRegisterInfo::reg_collection_const_range>())) {
234            const struct RegisterInfo &reginfo = x.value();
235            m_reg_valid[x.index()] =
236                (reginfo.byte_offset + reginfo.byte_size <=
237                 buffer_sp->GetByteSize());
238          }
239
240          m_gpacket_cached = true;
241          if (GetRegisterIsValid(reg))
242            return true;
243        } else {
244          Log *log(GetLog(GDBRLog::Thread | GDBRLog::Packets));
245          LLDB_LOGF(
246              log,
247              "error: GDBRemoteRegisterContext::ReadRegisterBytes tried "
248              "to read the "
249              "entire register context at once, expected at least %" PRId64
250              " bytes "
251              "but only got %" PRId64 " bytes.",
252              m_reg_data.GetByteSize(), buffer_sp->GetByteSize());
253          return false;
254        }
255      }
256    }
257    if (reg_info->value_regs) {
258      // Process this composite register request by delegating to the
259      // constituent primordial registers.
260
261      // Index of the primordial register.
262      bool success = true;
263      for (uint32_t idx = 0; success; ++idx) {
264        const uint32_t prim_reg = reg_info->value_regs[idx];
265        if (prim_reg == LLDB_INVALID_REGNUM)
266          break;
267        // We have a valid primordial register as our constituent. Grab the
268        // corresponding register info.
269        const RegisterInfo *prim_reg_info =
270            GetRegisterInfo(eRegisterKindLLDB, prim_reg);
271        if (prim_reg_info == nullptr)
272          success = false;
273        else {
274          // Read the containing register if it hasn't already been read
275          if (!GetRegisterIsValid(prim_reg))
276            success = GetPrimordialRegister(prim_reg_info, gdb_comm);
277        }
278      }
279
280      if (success) {
281        // If we reach this point, all primordial register requests have
282        // succeeded. Validate this composite register.
283        SetRegisterIsValid(reg_info, true);
284      }
285    } else {
286      // Get each register individually
287      GetPrimordialRegister(reg_info, gdb_comm);
288    }
289
290    // Make sure we got a valid register value after reading it
291    if (!GetRegisterIsValid(reg))
292      return false;
293  }
294
295  return true;
296}
297
298bool GDBRemoteRegisterContext::WriteRegister(const RegisterInfo *reg_info,
299                                             const RegisterValue &value) {
300  DataExtractor data;
301  if (value.GetData(data)) {
302    if (reg_info->value_regs &&
303        reg_info->value_regs[0] != LLDB_INVALID_REGNUM &&
304        reg_info->value_regs[1] != LLDB_INVALID_REGNUM) {
305      uint32_t combined_size = 0;
306      for (int i = 0; reg_info->value_regs[i] != LLDB_INVALID_REGNUM; i++) {
307        const RegisterInfo *parent_reg = GetRegisterInfo(
308            eRegisterKindLLDB, reg_info->value_regs[i]);
309        if (!parent_reg)
310          return false;
311        combined_size += parent_reg->byte_size;
312      }
313
314      if (data.GetByteSize() < combined_size)
315        return false;
316
317      uint32_t offset = 0;
318      for (int i = 0; reg_info->value_regs[i] != LLDB_INVALID_REGNUM; i++) {
319        const RegisterInfo *parent_reg = GetRegisterInfo(
320            eRegisterKindLLDB, reg_info->value_regs[i]);
321        assert(parent_reg);
322
323        DataExtractor parent_data{data, offset, parent_reg->byte_size};
324        if (!WriteRegisterBytes(parent_reg, parent_data, 0))
325          return false;
326        offset += parent_reg->byte_size;
327      }
328      assert(offset == combined_size);
329      return true;
330    } else
331      return WriteRegisterBytes(reg_info, data, 0);
332  }
333  return false;
334}
335
336// Helper function for GDBRemoteRegisterContext::WriteRegisterBytes().
337bool GDBRemoteRegisterContext::SetPrimordialRegister(
338    const RegisterInfo *reg_info, GDBRemoteCommunicationClient &gdb_comm) {
339  StreamString packet;
340  StringExtractorGDBRemote response;
341  const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
342  // Invalidate just this register
343  SetRegisterIsValid(reg, false);
344
345  return gdb_comm.WriteRegister(
346      m_thread.GetProtocolID(), reg_info->kinds[eRegisterKindProcessPlugin],
347      {m_reg_data.PeekData(reg_info->byte_offset, reg_info->byte_size),
348       reg_info->byte_size});
349}
350
351bool GDBRemoteRegisterContext::WriteRegisterBytes(const RegisterInfo *reg_info,
352                                                  DataExtractor &data,
353                                                  uint32_t data_offset) {
354  ExecutionContext exe_ctx(CalculateThread());
355
356  Process *process = exe_ctx.GetProcessPtr();
357  Thread *thread = exe_ctx.GetThreadPtr();
358  if (process == nullptr || thread == nullptr)
359    return false;
360
361  GDBRemoteCommunicationClient &gdb_comm(
362      ((ProcessGDBRemote *)process)->GetGDBRemote());
363
364  assert(m_reg_data.GetByteSize() >=
365         reg_info->byte_offset + reg_info->byte_size);
366
367  // If our register context and our register info disagree, which should never
368  // happen, don't overwrite past the end of the buffer.
369  if (m_reg_data.GetByteSize() < reg_info->byte_offset + reg_info->byte_size)
370    return false;
371
372  // Grab a pointer to where we are going to put this register
373  uint8_t *dst = const_cast<uint8_t *>(
374      m_reg_data.PeekData(reg_info->byte_offset, reg_info->byte_size));
375
376  if (dst == nullptr)
377    return false;
378
379  const bool should_reconfigure_registers =
380      RegisterWriteCausesReconfigure(reg_info->name);
381
382  if (data.CopyByteOrderedData(data_offset,                // src offset
383                               reg_info->byte_size,        // src length
384                               dst,                        // dst
385                               reg_info->byte_size,        // dst length
386                               m_reg_data.GetByteOrder())) // dst byte order
387  {
388    GDBRemoteClientBase::Lock lock(gdb_comm);
389    if (lock) {
390      if (m_write_all_at_once) {
391        // Invalidate all register values
392        InvalidateIfNeeded(true);
393
394        // Set all registers in one packet
395        if (gdb_comm.WriteAllRegisters(
396                m_thread.GetProtocolID(),
397                {m_reg_data.GetDataStart(), size_t(m_reg_data.GetByteSize())}))
398
399        {
400          if (should_reconfigure_registers)
401            ReconfigureRegisterInfo();
402
403          InvalidateAllRegisters();
404
405          return true;
406        }
407      } else {
408        bool success = true;
409
410        if (reg_info->value_regs) {
411          // This register is part of another register. In this case we read
412          // the actual register data for any "value_regs", and once all that
413          // data is read, we will have enough data in our register context
414          // bytes for the value of this register
415
416          // Invalidate this composite register first.
417
418          for (uint32_t idx = 0; success; ++idx) {
419            const uint32_t reg = reg_info->value_regs[idx];
420            if (reg == LLDB_INVALID_REGNUM)
421              break;
422            // We have a valid primordial register as our constituent. Grab the
423            // corresponding register info.
424            const RegisterInfo *value_reg_info =
425                GetRegisterInfo(eRegisterKindLLDB, reg);
426            if (value_reg_info == nullptr)
427              success = false;
428            else
429              success = SetPrimordialRegister(value_reg_info, gdb_comm);
430          }
431        } else {
432          // This is an actual register, write it
433          success = SetPrimordialRegister(reg_info, gdb_comm);
434        }
435
436        // Check if writing this register will invalidate any other register
437        // values? If so, invalidate them
438        if (reg_info->invalidate_regs) {
439          for (uint32_t idx = 0, reg = reg_info->invalidate_regs[0];
440               reg != LLDB_INVALID_REGNUM;
441               reg = reg_info->invalidate_regs[++idx])
442            SetRegisterIsValid(ConvertRegisterKindToRegisterNumber(
443                                   eRegisterKindLLDB, reg),
444                               false);
445        }
446
447        if (success && should_reconfigure_registers &&
448            ReconfigureRegisterInfo())
449          InvalidateAllRegisters();
450
451        return success;
452      }
453    } else {
454      Log *log(GetLog(GDBRLog::Thread | GDBRLog::Packets));
455      if (log) {
456        if (log->GetVerbose()) {
457          StreamString strm;
458          process->DumpPluginHistory(strm);
459          LLDB_LOGF(log,
460                    "error: failed to get packet sequence mutex, not sending "
461                    "write register for \"%s\":\n%s",
462                    reg_info->name, strm.GetData());
463        } else
464          LLDB_LOGF(log,
465                    "error: failed to get packet sequence mutex, not sending "
466                    "write register for \"%s\"",
467                    reg_info->name);
468      }
469    }
470  }
471  return false;
472}
473
474bool GDBRemoteRegisterContext::ReadAllRegisterValues(
475    RegisterCheckpoint &reg_checkpoint) {
476  ExecutionContext exe_ctx(CalculateThread());
477
478  Process *process = exe_ctx.GetProcessPtr();
479  Thread *thread = exe_ctx.GetThreadPtr();
480  if (process == nullptr || thread == nullptr)
481    return false;
482
483  GDBRemoteCommunicationClient &gdb_comm(
484      ((ProcessGDBRemote *)process)->GetGDBRemote());
485
486  uint32_t save_id = 0;
487  if (gdb_comm.SaveRegisterState(thread->GetProtocolID(), save_id)) {
488    reg_checkpoint.SetID(save_id);
489    reg_checkpoint.GetData().reset();
490    return true;
491  } else {
492    reg_checkpoint.SetID(0); // Invalid save ID is zero
493    return ReadAllRegisterValues(reg_checkpoint.GetData());
494  }
495}
496
497bool GDBRemoteRegisterContext::WriteAllRegisterValues(
498    const RegisterCheckpoint &reg_checkpoint) {
499  uint32_t save_id = reg_checkpoint.GetID();
500  if (save_id != 0) {
501    ExecutionContext exe_ctx(CalculateThread());
502
503    Process *process = exe_ctx.GetProcessPtr();
504    Thread *thread = exe_ctx.GetThreadPtr();
505    if (process == nullptr || thread == nullptr)
506      return false;
507
508    GDBRemoteCommunicationClient &gdb_comm(
509        ((ProcessGDBRemote *)process)->GetGDBRemote());
510
511    return gdb_comm.RestoreRegisterState(m_thread.GetProtocolID(), save_id);
512  } else {
513    return WriteAllRegisterValues(reg_checkpoint.GetData());
514  }
515}
516
517bool GDBRemoteRegisterContext::ReadAllRegisterValues(
518    lldb::WritableDataBufferSP &data_sp) {
519  ExecutionContext exe_ctx(CalculateThread());
520
521  Process *process = exe_ctx.GetProcessPtr();
522  Thread *thread = exe_ctx.GetThreadPtr();
523  if (process == nullptr || thread == nullptr)
524    return false;
525
526  GDBRemoteCommunicationClient &gdb_comm(
527      ((ProcessGDBRemote *)process)->GetGDBRemote());
528
529  const bool use_g_packet =
530      !gdb_comm.AvoidGPackets((ProcessGDBRemote *)process);
531
532  GDBRemoteClientBase::Lock lock(gdb_comm);
533  if (lock) {
534    if (gdb_comm.SyncThreadState(m_thread.GetProtocolID()))
535      InvalidateAllRegisters();
536
537    if (use_g_packet) {
538      if (DataBufferSP data_buffer =
539              gdb_comm.ReadAllRegisters(m_thread.GetProtocolID())) {
540        data_sp = std::make_shared<DataBufferHeap>(*data_buffer);
541        return true;
542      }
543    }
544
545    // We're going to read each register
546    // individually and store them as binary data in a buffer.
547    const RegisterInfo *reg_info;
548
549    for (uint32_t i = 0; (reg_info = GetRegisterInfoAtIndex(i)) != nullptr;
550         i++) {
551      if (reg_info
552              ->value_regs) // skip registers that are slices of real registers
553        continue;
554      ReadRegisterBytes(reg_info);
555      // ReadRegisterBytes saves the contents of the register in to the
556      // m_reg_data buffer
557    }
558    data_sp = std::make_shared<DataBufferHeap>(
559        m_reg_data.GetDataStart(), m_reg_info_sp->GetRegisterDataByteSize());
560    return true;
561  } else {
562
563    Log *log(GetLog(GDBRLog::Thread | GDBRLog::Packets));
564    if (log) {
565      if (log->GetVerbose()) {
566        StreamString strm;
567        process->DumpPluginHistory(strm);
568        LLDB_LOGF(log,
569                  "error: failed to get packet sequence mutex, not sending "
570                  "read all registers:\n%s",
571                  strm.GetData());
572      } else
573        LLDB_LOGF(log,
574                  "error: failed to get packet sequence mutex, not sending "
575                  "read all registers");
576    }
577  }
578
579  data_sp.reset();
580  return false;
581}
582
583bool GDBRemoteRegisterContext::WriteAllRegisterValues(
584    const lldb::DataBufferSP &data_sp) {
585  if (!data_sp || data_sp->GetBytes() == nullptr || data_sp->GetByteSize() == 0)
586    return false;
587
588  ExecutionContext exe_ctx(CalculateThread());
589
590  Process *process = exe_ctx.GetProcessPtr();
591  Thread *thread = exe_ctx.GetThreadPtr();
592  if (process == nullptr || thread == nullptr)
593    return false;
594
595  GDBRemoteCommunicationClient &gdb_comm(
596      ((ProcessGDBRemote *)process)->GetGDBRemote());
597
598  const bool use_g_packet =
599      !gdb_comm.AvoidGPackets((ProcessGDBRemote *)process);
600
601  GDBRemoteClientBase::Lock lock(gdb_comm);
602  if (lock) {
603    // The data_sp contains the G response packet.
604    if (use_g_packet) {
605      if (gdb_comm.WriteAllRegisters(
606              m_thread.GetProtocolID(),
607              {data_sp->GetBytes(), size_t(data_sp->GetByteSize())}))
608        return true;
609
610      uint32_t num_restored = 0;
611      // We need to manually go through all of the registers and restore them
612      // manually
613      DataExtractor restore_data(data_sp, m_reg_data.GetByteOrder(),
614                                 m_reg_data.GetAddressByteSize());
615
616      const RegisterInfo *reg_info;
617
618      // The g packet contents may either include the slice registers
619      // (registers defined in terms of other registers, e.g. eax is a subset
620      // of rax) or not.  The slice registers should NOT be in the g packet,
621      // but some implementations may incorrectly include them.
622      //
623      // If the slice registers are included in the packet, we must step over
624      // the slice registers when parsing the packet -- relying on the
625      // RegisterInfo byte_offset field would be incorrect. If the slice
626      // registers are not included, then using the byte_offset values into the
627      // data buffer is the best way to find individual register values.
628
629      uint64_t size_including_slice_registers = 0;
630      uint64_t size_not_including_slice_registers = 0;
631      uint64_t size_by_highest_offset = 0;
632
633      for (uint32_t reg_idx = 0;
634           (reg_info = GetRegisterInfoAtIndex(reg_idx)) != nullptr; ++reg_idx) {
635        size_including_slice_registers += reg_info->byte_size;
636        if (reg_info->value_regs == nullptr)
637          size_not_including_slice_registers += reg_info->byte_size;
638        if (reg_info->byte_offset >= size_by_highest_offset)
639          size_by_highest_offset = reg_info->byte_offset + reg_info->byte_size;
640      }
641
642      bool use_byte_offset_into_buffer;
643      if (size_by_highest_offset == restore_data.GetByteSize()) {
644        // The size of the packet agrees with the highest offset: + size in the
645        // register file
646        use_byte_offset_into_buffer = true;
647      } else if (size_not_including_slice_registers ==
648                 restore_data.GetByteSize()) {
649        // The size of the packet is the same as concatenating all of the
650        // registers sequentially, skipping the slice registers
651        use_byte_offset_into_buffer = true;
652      } else if (size_including_slice_registers == restore_data.GetByteSize()) {
653        // The slice registers are present in the packet (when they shouldn't
654        // be). Don't try to use the RegisterInfo byte_offset into the
655        // restore_data, it will point to the wrong place.
656        use_byte_offset_into_buffer = false;
657      } else {
658        // None of our expected sizes match the actual g packet data we're
659        // looking at. The most conservative approach here is to use the
660        // running total byte offset.
661        use_byte_offset_into_buffer = false;
662      }
663
664      // In case our register definitions don't include the correct offsets,
665      // keep track of the size of each reg & compute offset based on that.
666      uint32_t running_byte_offset = 0;
667      for (uint32_t reg_idx = 0;
668           (reg_info = GetRegisterInfoAtIndex(reg_idx)) != nullptr;
669           ++reg_idx, running_byte_offset += reg_info->byte_size) {
670        // Skip composite aka slice registers (e.g. eax is a slice of rax).
671        if (reg_info->value_regs)
672          continue;
673
674        const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
675
676        uint32_t register_offset;
677        if (use_byte_offset_into_buffer) {
678          register_offset = reg_info->byte_offset;
679        } else {
680          register_offset = running_byte_offset;
681        }
682
683        const uint32_t reg_byte_size = reg_info->byte_size;
684
685        const uint8_t *restore_src =
686            restore_data.PeekData(register_offset, reg_byte_size);
687        if (restore_src) {
688          SetRegisterIsValid(reg, false);
689          if (gdb_comm.WriteRegister(
690                  m_thread.GetProtocolID(),
691                  reg_info->kinds[eRegisterKindProcessPlugin],
692                  {restore_src, reg_byte_size}))
693            ++num_restored;
694        }
695      }
696      return num_restored > 0;
697    } else {
698      // For the use_g_packet == false case, we're going to write each register
699      // individually.  The data buffer is binary data in this case, instead of
700      // ascii characters.
701
702      bool arm64_debugserver = false;
703      if (m_thread.GetProcess().get()) {
704        const ArchSpec &arch =
705            m_thread.GetProcess()->GetTarget().GetArchitecture();
706        if (arch.IsValid() && (arch.GetMachine() == llvm::Triple::aarch64 ||
707                               arch.GetMachine() == llvm::Triple::aarch64_32) &&
708            arch.GetTriple().getVendor() == llvm::Triple::Apple &&
709            arch.GetTriple().getOS() == llvm::Triple::IOS) {
710          arm64_debugserver = true;
711        }
712      }
713      uint32_t num_restored = 0;
714      const RegisterInfo *reg_info;
715      for (uint32_t i = 0; (reg_info = GetRegisterInfoAtIndex(i)) != nullptr;
716           i++) {
717        if (reg_info->value_regs) // skip registers that are slices of real
718                                  // registers
719          continue;
720        // Skip the fpsr and fpcr floating point status/control register
721        // writing to work around a bug in an older version of debugserver that
722        // would lead to register context corruption when writing fpsr/fpcr.
723        if (arm64_debugserver && (strcmp(reg_info->name, "fpsr") == 0 ||
724                                  strcmp(reg_info->name, "fpcr") == 0)) {
725          continue;
726        }
727
728        SetRegisterIsValid(reg_info, false);
729        if (gdb_comm.WriteRegister(m_thread.GetProtocolID(),
730                                   reg_info->kinds[eRegisterKindProcessPlugin],
731                                   {data_sp->GetBytes() + reg_info->byte_offset,
732                                    reg_info->byte_size}))
733          ++num_restored;
734      }
735      return num_restored > 0;
736    }
737  } else {
738    Log *log(GetLog(GDBRLog::Thread | GDBRLog::Packets));
739    if (log) {
740      if (log->GetVerbose()) {
741        StreamString strm;
742        process->DumpPluginHistory(strm);
743        LLDB_LOGF(log,
744                  "error: failed to get packet sequence mutex, not sending "
745                  "write all registers:\n%s",
746                  strm.GetData());
747      } else
748        LLDB_LOGF(log,
749                  "error: failed to get packet sequence mutex, not sending "
750                  "write all registers");
751    }
752  }
753  return false;
754}
755
756uint32_t GDBRemoteRegisterContext::ConvertRegisterKindToRegisterNumber(
757    lldb::RegisterKind kind, uint32_t num) {
758  return m_reg_info_sp->ConvertRegisterKindToRegisterNumber(kind, num);
759}
760
761bool GDBRemoteRegisterContext::RegisterWriteCausesReconfigure(
762    const llvm::StringRef name) {
763  ExecutionContext exe_ctx(CalculateThread());
764  const Architecture *architecture =
765      exe_ctx.GetProcessRef().GetTarget().GetArchitecturePlugin();
766  return architecture && architecture->RegisterWriteCausesReconfigure(name);
767}
768
769bool GDBRemoteRegisterContext::ReconfigureRegisterInfo() {
770  ExecutionContext exe_ctx(CalculateThread());
771  const Architecture *architecture =
772      exe_ctx.GetProcessRef().GetTarget().GetArchitecturePlugin();
773  if (architecture)
774    return architecture->ReconfigureRegisterInfo(*(m_reg_info_sp.get()),
775                                                 m_reg_data, *this);
776  return false;
777}
778