1//===-- NativeRegisterContext.cpp -------------------------*- C++ -*-===//
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 "lldb/Host/common/NativeRegisterContext.h"
10
11#include "lldb/Utility/Log.h"
12#include "lldb/Utility/RegisterValue.h"
13
14#include "lldb/Host/PosixApi.h"
15#include "lldb/Host/common/NativeProcessProtocol.h"
16#include "lldb/Host/common/NativeThreadProtocol.h"
17
18using namespace lldb;
19using namespace lldb_private;
20
21NativeRegisterContext::NativeRegisterContext(NativeThreadProtocol &thread)
22    : m_thread(thread) {}
23
24// Destructor
25NativeRegisterContext::~NativeRegisterContext() {}
26
27// FIXME revisit invalidation, process stop ids, etc.  Right now we don't
28// support caching in NativeRegisterContext.  We can do this later by utilizing
29// NativeProcessProtocol::GetStopID () and adding a stop id to
30// NativeRegisterContext.
31
32// void
33// NativeRegisterContext::InvalidateIfNeeded (bool force) {
34//     ProcessSP process_sp (m_thread.GetProcess());
35//     bool invalidate = force;
36//     uint32_t process_stop_id = UINT32_MAX;
37
38//     if (process_sp)
39//         process_stop_id = process_sp->GetStopID();
40//     else
41//         invalidate = true;
42
43//     if (!invalidate)
44//         invalidate = process_stop_id != GetStopID();
45
46//     if (invalidate)
47//     {
48//         InvalidateAllRegisters ();
49//         SetStopID (process_stop_id);
50//     }
51// }
52
53const RegisterInfo *
54NativeRegisterContext::GetRegisterInfoByName(llvm::StringRef reg_name,
55                                             uint32_t start_idx) {
56  if (reg_name.empty())
57    return nullptr;
58
59  const uint32_t num_registers = GetRegisterCount();
60  for (uint32_t reg = start_idx; reg < num_registers; ++reg) {
61    const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg);
62
63    if (reg_name.equals_lower(reg_info->name) ||
64        reg_name.equals_lower(reg_info->alt_name))
65      return reg_info;
66  }
67  return nullptr;
68}
69
70const RegisterInfo *NativeRegisterContext::GetRegisterInfo(uint32_t kind,
71                                                           uint32_t num) {
72  const uint32_t reg_num = ConvertRegisterKindToRegisterNumber(kind, num);
73  if (reg_num == LLDB_INVALID_REGNUM)
74    return nullptr;
75  return GetRegisterInfoAtIndex(reg_num);
76}
77
78const char *NativeRegisterContext::GetRegisterName(uint32_t reg) {
79  const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg);
80  if (reg_info)
81    return reg_info->name;
82  return nullptr;
83}
84
85const char *NativeRegisterContext::GetRegisterSetNameForRegisterAtIndex(
86    uint32_t reg_index) const {
87  const RegisterInfo *const reg_info = GetRegisterInfoAtIndex(reg_index);
88  if (!reg_info)
89    return nullptr;
90
91  for (uint32_t set_index = 0; set_index < GetRegisterSetCount(); ++set_index) {
92    const RegisterSet *const reg_set = GetRegisterSet(set_index);
93    if (!reg_set)
94      continue;
95
96    for (uint32_t reg_num_index = 0; reg_num_index < reg_set->num_registers;
97         ++reg_num_index) {
98      const uint32_t reg_num = reg_set->registers[reg_num_index];
99      // FIXME double check we're checking the right register kind here.
100      if (reg_info->kinds[RegisterKind::eRegisterKindLLDB] == reg_num) {
101        // The given register is a member of this register set.  Return the
102        // register set name.
103        return reg_set->name;
104      }
105    }
106  }
107
108  // Didn't find it.
109  return nullptr;
110}
111
112lldb::addr_t NativeRegisterContext::GetPC(lldb::addr_t fail_value) {
113  Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
114
115  uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
116                                                     LLDB_REGNUM_GENERIC_PC);
117  LLDB_LOGF(log,
118            "NativeRegisterContext::%s using reg index %" PRIu32
119            " (default %" PRIu64 ")",
120            __FUNCTION__, reg, fail_value);
121
122  const uint64_t retval = ReadRegisterAsUnsigned(reg, fail_value);
123
124  LLDB_LOGF(log, "NativeRegisterContext::%s " PRIu32 " retval %" PRIu64,
125            __FUNCTION__, retval);
126
127  return retval;
128}
129
130lldb::addr_t
131NativeRegisterContext::GetPCfromBreakpointLocation(lldb::addr_t fail_value) {
132  return GetPC(fail_value);
133}
134
135Status NativeRegisterContext::SetPC(lldb::addr_t pc) {
136  uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
137                                                     LLDB_REGNUM_GENERIC_PC);
138  return WriteRegisterFromUnsigned(reg, pc);
139}
140
141lldb::addr_t NativeRegisterContext::GetSP(lldb::addr_t fail_value) {
142  uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
143                                                     LLDB_REGNUM_GENERIC_SP);
144  return ReadRegisterAsUnsigned(reg, fail_value);
145}
146
147Status NativeRegisterContext::SetSP(lldb::addr_t sp) {
148  uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
149                                                     LLDB_REGNUM_GENERIC_SP);
150  return WriteRegisterFromUnsigned(reg, sp);
151}
152
153lldb::addr_t NativeRegisterContext::GetFP(lldb::addr_t fail_value) {
154  uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
155                                                     LLDB_REGNUM_GENERIC_FP);
156  return ReadRegisterAsUnsigned(reg, fail_value);
157}
158
159Status NativeRegisterContext::SetFP(lldb::addr_t fp) {
160  uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
161                                                     LLDB_REGNUM_GENERIC_FP);
162  return WriteRegisterFromUnsigned(reg, fp);
163}
164
165lldb::addr_t NativeRegisterContext::GetReturnAddress(lldb::addr_t fail_value) {
166  uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
167                                                     LLDB_REGNUM_GENERIC_RA);
168  return ReadRegisterAsUnsigned(reg, fail_value);
169}
170
171lldb::addr_t NativeRegisterContext::GetFlags(lldb::addr_t fail_value) {
172  uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
173                                                     LLDB_REGNUM_GENERIC_FLAGS);
174  return ReadRegisterAsUnsigned(reg, fail_value);
175}
176
177lldb::addr_t
178NativeRegisterContext::ReadRegisterAsUnsigned(uint32_t reg,
179                                              lldb::addr_t fail_value) {
180  if (reg != LLDB_INVALID_REGNUM)
181    return ReadRegisterAsUnsigned(GetRegisterInfoAtIndex(reg), fail_value);
182  return fail_value;
183}
184
185uint64_t
186NativeRegisterContext::ReadRegisterAsUnsigned(const RegisterInfo *reg_info,
187                                              lldb::addr_t fail_value) {
188  Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
189
190  if (reg_info) {
191    RegisterValue value;
192    Status error = ReadRegister(reg_info, value);
193    if (error.Success()) {
194      LLDB_LOGF(log,
195                "NativeRegisterContext::%s ReadRegister() succeeded, value "
196                "%" PRIu64,
197                __FUNCTION__, value.GetAsUInt64());
198      return value.GetAsUInt64();
199    } else {
200      LLDB_LOGF(log,
201                "NativeRegisterContext::%s ReadRegister() failed, error %s",
202                __FUNCTION__, error.AsCString());
203    }
204  } else {
205    LLDB_LOGF(log, "NativeRegisterContext::%s ReadRegister() null reg_info",
206              __FUNCTION__);
207  }
208  return fail_value;
209}
210
211Status NativeRegisterContext::WriteRegisterFromUnsigned(uint32_t reg,
212                                                        uint64_t uval) {
213  if (reg == LLDB_INVALID_REGNUM)
214    return Status("NativeRegisterContext::%s (): reg is invalid", __FUNCTION__);
215  return WriteRegisterFromUnsigned(GetRegisterInfoAtIndex(reg), uval);
216}
217
218Status
219NativeRegisterContext::WriteRegisterFromUnsigned(const RegisterInfo *reg_info,
220                                                 uint64_t uval) {
221  assert(reg_info);
222  if (!reg_info)
223    return Status("reg_info is nullptr");
224
225  RegisterValue value;
226  if (!value.SetUInt(uval, reg_info->byte_size))
227    return Status("RegisterValue::SetUInt () failed");
228
229  return WriteRegister(reg_info, value);
230}
231
232lldb::tid_t NativeRegisterContext::GetThreadID() const {
233  return m_thread.GetID();
234}
235
236uint32_t NativeRegisterContext::NumSupportedHardwareBreakpoints() { return 0; }
237
238uint32_t NativeRegisterContext::SetHardwareBreakpoint(lldb::addr_t addr,
239                                                      size_t size) {
240  return LLDB_INVALID_INDEX32;
241}
242
243Status NativeRegisterContext::ClearAllHardwareBreakpoints() {
244  return Status("not implemented");
245}
246
247bool NativeRegisterContext::ClearHardwareBreakpoint(uint32_t hw_idx) {
248  return false;
249}
250
251Status NativeRegisterContext::GetHardwareBreakHitIndex(uint32_t &bp_index,
252                                                       lldb::addr_t trap_addr) {
253  bp_index = LLDB_INVALID_INDEX32;
254  return Status("not implemented");
255}
256
257uint32_t NativeRegisterContext::NumSupportedHardwareWatchpoints() { return 0; }
258
259uint32_t NativeRegisterContext::SetHardwareWatchpoint(lldb::addr_t addr,
260                                                      size_t size,
261                                                      uint32_t watch_flags) {
262  return LLDB_INVALID_INDEX32;
263}
264
265bool NativeRegisterContext::ClearHardwareWatchpoint(uint32_t hw_index) {
266  return false;
267}
268
269Status NativeRegisterContext::ClearAllHardwareWatchpoints() {
270  return Status("not implemented");
271}
272
273Status NativeRegisterContext::IsWatchpointHit(uint32_t wp_index, bool &is_hit) {
274  is_hit = false;
275  return Status("not implemented");
276}
277
278Status NativeRegisterContext::GetWatchpointHitIndex(uint32_t &wp_index,
279                                                    lldb::addr_t trap_addr) {
280  wp_index = LLDB_INVALID_INDEX32;
281  return Status("not implemented");
282}
283
284Status NativeRegisterContext::IsWatchpointVacant(uint32_t wp_index,
285                                                 bool &is_vacant) {
286  is_vacant = false;
287  return Status("not implemented");
288}
289
290lldb::addr_t NativeRegisterContext::GetWatchpointAddress(uint32_t wp_index) {
291  return LLDB_INVALID_ADDRESS;
292}
293
294lldb::addr_t NativeRegisterContext::GetWatchpointHitAddress(uint32_t wp_index) {
295  return LLDB_INVALID_ADDRESS;
296}
297
298bool NativeRegisterContext::HardwareSingleStep(bool enable) { return false; }
299
300Status NativeRegisterContext::ReadRegisterValueFromMemory(
301    const RegisterInfo *reg_info, lldb::addr_t src_addr, size_t src_len,
302    RegisterValue &reg_value) {
303  Status error;
304  if (reg_info == nullptr) {
305    error.SetErrorString("invalid register info argument.");
306    return error;
307  }
308
309  // Moving from addr into a register
310  //
311  // Case 1: src_len == dst_len
312  //
313  //   |AABBCCDD| Address contents
314  //   |AABBCCDD| Register contents
315  //
316  // Case 2: src_len > dst_len
317  //
318  //   Status!  (The register should always be big enough to hold the data)
319  //
320  // Case 3: src_len < dst_len
321  //
322  //   |AABB| Address contents
323  //   |AABB0000| Register contents [on little-endian hardware]
324  //   |0000AABB| Register contents [on big-endian hardware]
325  if (src_len > RegisterValue::kMaxRegisterByteSize) {
326    error.SetErrorString("register too small to receive memory data");
327    return error;
328  }
329
330  const size_t dst_len = reg_info->byte_size;
331
332  if (src_len > dst_len) {
333    error.SetErrorStringWithFormat(
334        "%" PRIu64 " bytes is too big to store in register %s (%" PRIu64
335        " bytes)",
336        static_cast<uint64_t>(src_len), reg_info->name,
337        static_cast<uint64_t>(dst_len));
338    return error;
339  }
340
341  NativeProcessProtocol &process = m_thread.GetProcess();
342  uint8_t src[RegisterValue::kMaxRegisterByteSize];
343
344  // Read the memory
345  size_t bytes_read;
346  error = process.ReadMemory(src_addr, src, src_len, bytes_read);
347  if (error.Fail())
348    return error;
349
350  // Make sure the memory read succeeded...
351  if (bytes_read != src_len) {
352    // This might happen if we read _some_ bytes but not all
353    error.SetErrorStringWithFormat("read %" PRIu64 " of %" PRIu64 " bytes",
354                                   static_cast<uint64_t>(bytes_read),
355                                   static_cast<uint64_t>(src_len));
356    return error;
357  }
358
359  // We now have a memory buffer that contains the part or all of the register
360  // value. Set the register value using this memory data.
361  // TODO: we might need to add a parameter to this function in case the byte
362  // order of the memory data doesn't match the process. For now we are
363  // assuming they are the same.
364  reg_value.SetFromMemoryData(reg_info, src, src_len, process.GetByteOrder(),
365                              error);
366
367  return error;
368}
369
370Status NativeRegisterContext::WriteRegisterValueToMemory(
371    const RegisterInfo *reg_info, lldb::addr_t dst_addr, size_t dst_len,
372    const RegisterValue &reg_value) {
373
374  uint8_t dst[RegisterValue::kMaxRegisterByteSize];
375
376  Status error;
377
378  NativeProcessProtocol &process = m_thread.GetProcess();
379
380  // TODO: we might need to add a parameter to this function in case the byte
381  // order of the memory data doesn't match the process. For now we are
382  // assuming they are the same.
383  const size_t bytes_copied = reg_value.GetAsMemoryData(
384      reg_info, dst, dst_len, process.GetByteOrder(), error);
385
386  if (error.Success()) {
387    if (bytes_copied == 0) {
388      error.SetErrorString("byte copy failed.");
389    } else {
390      size_t bytes_written;
391      error = process.WriteMemory(dst_addr, dst, bytes_copied, bytes_written);
392      if (error.Fail())
393        return error;
394
395      if (bytes_written != bytes_copied) {
396        // This might happen if we read _some_ bytes but not all
397        error.SetErrorStringWithFormat("only wrote %" PRIu64 " of %" PRIu64
398                                       " bytes",
399                                       static_cast<uint64_t>(bytes_written),
400                                       static_cast<uint64_t>(bytes_copied));
401      }
402    }
403  }
404
405  return error;
406}
407
408uint32_t
409NativeRegisterContext::ConvertRegisterKindToRegisterNumber(uint32_t kind,
410                                                           uint32_t num) const {
411  const uint32_t num_regs = GetRegisterCount();
412
413  assert(kind < kNumRegisterKinds);
414  for (uint32_t reg_idx = 0; reg_idx < num_regs; ++reg_idx) {
415    const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg_idx);
416
417    if (reg_info->kinds[kind] == num)
418      return reg_idx;
419  }
420
421  return LLDB_INVALID_REGNUM;
422}
423