1 //===-- RegisterContext.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 "lldb/Target/RegisterContext.h" 10 #include "lldb/Core/Module.h" 11 #include "lldb/Core/Value.h" 12 #include "lldb/Expression/DWARFExpression.h" 13 #include "lldb/Target/ExecutionContext.h" 14 #include "lldb/Target/Process.h" 15 #include "lldb/Target/StackFrame.h" 16 #include "lldb/Target/Target.h" 17 #include "lldb/Target/Thread.h" 18 #include "lldb/Utility/DataExtractor.h" 19 #include "lldb/Utility/Endian.h" 20 #include "lldb/Utility/RegisterValue.h" 21 #include "lldb/Utility/Scalar.h" 22 23 using namespace lldb; 24 using namespace lldb_private; 25 26 RegisterContext::RegisterContext(Thread &thread, uint32_t concrete_frame_idx) 27 : m_thread(thread), m_concrete_frame_idx(concrete_frame_idx), 28 m_stop_id(thread.GetProcess()->GetStopID()) {} 29 30 RegisterContext::~RegisterContext() = default; 31 32 void RegisterContext::InvalidateIfNeeded(bool force) { 33 ProcessSP process_sp(m_thread.GetProcess()); 34 bool invalidate = force; 35 uint32_t process_stop_id = UINT32_MAX; 36 37 if (process_sp) 38 process_stop_id = process_sp->GetStopID(); 39 else 40 invalidate = true; 41 42 if (!invalidate) 43 invalidate = process_stop_id != GetStopID(); 44 45 if (invalidate) { 46 InvalidateAllRegisters(); 47 SetStopID(process_stop_id); 48 } 49 } 50 51 const RegisterInfo * 52 RegisterContext::GetRegisterInfoByName(llvm::StringRef reg_name, 53 uint32_t start_idx) { 54 if (reg_name.empty()) 55 return nullptr; 56 57 // Generic register names take precedence over specific register names. 58 // For example, on x86 we want "sp" to refer to the complete RSP/ESP register 59 // rather than the 16-bit SP pseudo-register. 60 uint32_t generic_reg = Args::StringToGenericRegister(reg_name); 61 if (generic_reg != LLDB_INVALID_REGNUM) { 62 const RegisterInfo *reg_info = 63 GetRegisterInfo(eRegisterKindGeneric, generic_reg); 64 if (reg_info) 65 return reg_info; 66 } 67 68 const uint32_t num_registers = GetRegisterCount(); 69 for (uint32_t reg = start_idx; reg < num_registers; ++reg) { 70 const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg); 71 72 if (reg_name.equals_insensitive(reg_info->name) || 73 reg_name.equals_insensitive(reg_info->alt_name)) 74 return reg_info; 75 } 76 77 return nullptr; 78 } 79 80 const RegisterInfo *RegisterContext::GetRegisterInfo(lldb::RegisterKind kind, 81 uint32_t num) { 82 const uint32_t reg_num = ConvertRegisterKindToRegisterNumber(kind, num); 83 if (reg_num == LLDB_INVALID_REGNUM) 84 return nullptr; 85 return GetRegisterInfoAtIndex(reg_num); 86 } 87 88 const char *RegisterContext::GetRegisterName(uint32_t reg) { 89 const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg); 90 if (reg_info) 91 return reg_info->name; 92 return nullptr; 93 } 94 95 uint64_t RegisterContext::GetPC(uint64_t fail_value) { 96 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 97 LLDB_REGNUM_GENERIC_PC); 98 uint64_t pc = ReadRegisterAsUnsigned(reg, fail_value); 99 100 if (pc != fail_value) { 101 TargetSP target_sp = m_thread.CalculateTarget(); 102 if (target_sp) { 103 Target *target = target_sp.get(); 104 if (target) 105 pc = target->GetOpcodeLoadAddress(pc, AddressClass::eCode); 106 } 107 } 108 109 return pc; 110 } 111 112 bool RegisterContext::SetPC(uint64_t pc) { 113 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 114 LLDB_REGNUM_GENERIC_PC); 115 bool success = WriteRegisterFromUnsigned(reg, pc); 116 if (success) { 117 StackFrameSP frame_sp( 118 m_thread.GetFrameWithConcreteFrameIndex(m_concrete_frame_idx)); 119 if (frame_sp) 120 frame_sp->ChangePC(pc); 121 else 122 m_thread.ClearStackFrames(); 123 } 124 return success; 125 } 126 127 bool RegisterContext::GetPCForSymbolication(Address &address) { 128 addr_t pc = GetPC(LLDB_INVALID_ADDRESS); 129 if (pc == LLDB_INVALID_ADDRESS) 130 return false; 131 TargetSP target_sp = m_thread.CalculateTarget(); 132 if (!target_sp.get()) 133 return false; 134 135 if (!BehavesLikeZerothFrame() && pc != 0) 136 pc--; 137 address.SetLoadAddress(pc, target_sp.get()); 138 return true; 139 } 140 141 bool RegisterContext::SetPC(Address addr) { 142 TargetSP target_sp = m_thread.CalculateTarget(); 143 Target *target = target_sp.get(); 144 145 lldb::addr_t callAddr = addr.GetCallableLoadAddress(target); 146 if (callAddr == LLDB_INVALID_ADDRESS) 147 return false; 148 149 return SetPC(callAddr); 150 } 151 152 uint64_t RegisterContext::GetSP(uint64_t fail_value) { 153 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 154 LLDB_REGNUM_GENERIC_SP); 155 return ReadRegisterAsUnsigned(reg, fail_value); 156 } 157 158 bool RegisterContext::SetSP(uint64_t sp) { 159 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 160 LLDB_REGNUM_GENERIC_SP); 161 return WriteRegisterFromUnsigned(reg, sp); 162 } 163 164 uint64_t RegisterContext::GetFP(uint64_t fail_value) { 165 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 166 LLDB_REGNUM_GENERIC_FP); 167 return ReadRegisterAsUnsigned(reg, fail_value); 168 } 169 170 bool RegisterContext::SetFP(uint64_t fp) { 171 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 172 LLDB_REGNUM_GENERIC_FP); 173 return WriteRegisterFromUnsigned(reg, fp); 174 } 175 176 uint64_t RegisterContext::GetReturnAddress(uint64_t fail_value) { 177 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 178 LLDB_REGNUM_GENERIC_RA); 179 return ReadRegisterAsUnsigned(reg, fail_value); 180 } 181 182 uint64_t RegisterContext::GetFlags(uint64_t fail_value) { 183 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 184 LLDB_REGNUM_GENERIC_FLAGS); 185 return ReadRegisterAsUnsigned(reg, fail_value); 186 } 187 188 uint64_t RegisterContext::ReadRegisterAsUnsigned(uint32_t reg, 189 uint64_t fail_value) { 190 if (reg != LLDB_INVALID_REGNUM) 191 return ReadRegisterAsUnsigned(GetRegisterInfoAtIndex(reg), fail_value); 192 return fail_value; 193 } 194 195 uint64_t RegisterContext::ReadRegisterAsUnsigned(const RegisterInfo *reg_info, 196 uint64_t fail_value) { 197 if (reg_info) { 198 RegisterValue value; 199 if (ReadRegister(reg_info, value)) 200 return value.GetAsUInt64(); 201 } 202 return fail_value; 203 } 204 205 bool RegisterContext::WriteRegisterFromUnsigned(uint32_t reg, uint64_t uval) { 206 if (reg == LLDB_INVALID_REGNUM) 207 return false; 208 return WriteRegisterFromUnsigned(GetRegisterInfoAtIndex(reg), uval); 209 } 210 211 bool RegisterContext::WriteRegisterFromUnsigned(const RegisterInfo *reg_info, 212 uint64_t uval) { 213 if (reg_info) { 214 RegisterValue value; 215 if (value.SetUInt(uval, reg_info->byte_size)) 216 return WriteRegister(reg_info, value); 217 } 218 return false; 219 } 220 221 bool RegisterContext::CopyFromRegisterContext(lldb::RegisterContextSP context) { 222 uint32_t num_register_sets = context->GetRegisterSetCount(); 223 // We don't know that two threads have the same register context, so require 224 // the threads to be the same. 225 if (context->GetThreadID() != GetThreadID()) 226 return false; 227 228 if (num_register_sets != GetRegisterSetCount()) 229 return false; 230 231 RegisterContextSP frame_zero_context = m_thread.GetRegisterContext(); 232 233 for (uint32_t set_idx = 0; set_idx < num_register_sets; ++set_idx) { 234 const RegisterSet *const reg_set = GetRegisterSet(set_idx); 235 236 const uint32_t num_registers = reg_set->num_registers; 237 for (uint32_t reg_idx = 0; reg_idx < num_registers; ++reg_idx) { 238 const uint32_t reg = reg_set->registers[reg_idx]; 239 const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg); 240 if (!reg_info || reg_info->value_regs) 241 continue; 242 RegisterValue reg_value; 243 244 // If we can reconstruct the register from the frame we are copying from, 245 // then do so, otherwise use the value from frame 0. 246 if (context->ReadRegister(reg_info, reg_value)) { 247 WriteRegister(reg_info, reg_value); 248 } else if (frame_zero_context->ReadRegister(reg_info, reg_value)) { 249 WriteRegister(reg_info, reg_value); 250 } 251 } 252 } 253 return true; 254 } 255 256 lldb::tid_t RegisterContext::GetThreadID() const { return m_thread.GetID(); } 257 258 uint32_t RegisterContext::NumSupportedHardwareBreakpoints() { return 0; } 259 260 uint32_t RegisterContext::SetHardwareBreakpoint(lldb::addr_t addr, 261 size_t size) { 262 return LLDB_INVALID_INDEX32; 263 } 264 265 // Used when parsing DWARF and EH frame information and any other object file 266 // sections that contain register numbers in them. 267 uint32_t 268 RegisterContext::ConvertRegisterKindToRegisterNumber(lldb::RegisterKind kind, 269 uint32_t num) { 270 const uint32_t num_regs = GetRegisterCount(); 271 272 assert(kind < kNumRegisterKinds); 273 for (uint32_t reg_idx = 0; reg_idx < num_regs; ++reg_idx) { 274 const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg_idx); 275 276 if (reg_info->kinds[kind] == num) 277 return reg_idx; 278 } 279 280 return LLDB_INVALID_REGNUM; 281 } 282 283 bool RegisterContext::ClearHardwareBreakpoint(uint32_t hw_idx) { return false; } 284 285 uint32_t RegisterContext::NumSupportedHardwareWatchpoints() { return 0; } 286 287 uint32_t RegisterContext::SetHardwareWatchpoint(lldb::addr_t addr, size_t size, 288 bool read, bool write) { 289 return LLDB_INVALID_INDEX32; 290 } 291 292 bool RegisterContext::ClearHardwareWatchpoint(uint32_t hw_index) { 293 return false; 294 } 295 296 bool RegisterContext::HardwareSingleStep(bool enable) { return false; } 297 298 Status RegisterContext::ReadRegisterValueFromMemory( 299 const RegisterInfo *reg_info, lldb::addr_t src_addr, uint32_t src_len, 300 RegisterValue ®_value) { 301 Status error; 302 if (reg_info == nullptr) { 303 error.SetErrorString("invalid register info argument."); 304 return error; 305 } 306 307 // Moving from addr into a register 308 // 309 // Case 1: src_len == dst_len 310 // 311 // |AABBCCDD| Address contents 312 // |AABBCCDD| Register contents 313 // 314 // Case 2: src_len > dst_len 315 // 316 // Status! (The register should always be big enough to hold the data) 317 // 318 // Case 3: src_len < dst_len 319 // 320 // |AABB| Address contents 321 // |AABB0000| Register contents [on little-endian hardware] 322 // |0000AABB| Register contents [on big-endian hardware] 323 if (src_len > RegisterValue::kMaxRegisterByteSize) { 324 error.SetErrorString("register too small to receive memory data"); 325 return error; 326 } 327 328 const uint32_t dst_len = reg_info->byte_size; 329 330 if (src_len > dst_len) { 331 error.SetErrorStringWithFormat( 332 "%u bytes is too big to store in register %s (%u bytes)", src_len, 333 reg_info->name, dst_len); 334 return error; 335 } 336 337 ProcessSP process_sp(m_thread.GetProcess()); 338 if (process_sp) { 339 uint8_t src[RegisterValue::kMaxRegisterByteSize]; 340 341 // Read the memory 342 const uint32_t bytes_read = 343 process_sp->ReadMemory(src_addr, src, src_len, error); 344 345 // Make sure the memory read succeeded... 346 if (bytes_read != src_len) { 347 if (error.Success()) { 348 // This might happen if we read _some_ bytes but not all 349 error.SetErrorStringWithFormat("read %u of %u bytes", bytes_read, 350 src_len); 351 } 352 return error; 353 } 354 355 // We now have a memory buffer that contains the part or all of the 356 // register value. Set the register value using this memory data. 357 // TODO: we might need to add a parameter to this function in case the byte 358 // order of the memory data doesn't match the process. For now we are 359 // assuming they are the same. 360 reg_value.SetFromMemoryData(*reg_info, src, src_len, 361 process_sp->GetByteOrder(), error); 362 } else 363 error.SetErrorString("invalid process"); 364 365 return error; 366 } 367 368 Status RegisterContext::WriteRegisterValueToMemory( 369 const RegisterInfo *reg_info, lldb::addr_t dst_addr, uint32_t dst_len, 370 const RegisterValue ®_value) { 371 Status error; 372 ProcessSP process_sp(m_thread.GetProcess()); 373 374 if (!process_sp) { 375 error.SetErrorString("invalid process"); 376 return error; 377 } 378 379 if (reg_info == nullptr) { 380 error.SetErrorString("Invalid register info argument."); 381 return error; 382 } 383 384 // TODO: we might need to add a parameter to this function in case the byte 385 // order of the memory data doesn't match the process. For now we are 386 // assuming they are the same. 387 uint8_t dst[RegisterValue::kMaxRegisterByteSize]; 388 const uint32_t bytes_copied = reg_value.GetAsMemoryData( 389 *reg_info, dst, dst_len, process_sp->GetByteOrder(), error); 390 391 if (error.Success()) { 392 if (bytes_copied == 0) { 393 error.SetErrorString("byte copy failed."); 394 } else { 395 const uint32_t bytes_written = 396 process_sp->WriteMemory(dst_addr, dst, bytes_copied, error); 397 if (bytes_written != bytes_copied) { 398 if (error.Success()) { 399 // This might happen if we read _some_ bytes but not all 400 error.SetErrorStringWithFormat("only wrote %u of %u bytes", 401 bytes_written, bytes_copied); 402 } 403 } 404 } 405 } 406 407 return error; 408 } 409 410 lldb::ByteOrder RegisterContext::GetByteOrder() { 411 // Get the target process whose privileged thread was used for the register 412 // read. 413 lldb::ByteOrder byte_order = lldb::eByteOrderInvalid; 414 lldb_private::Process *process = CalculateProcess().get(); 415 416 if (process) 417 byte_order = process->GetByteOrder(); 418 return byte_order; 419 } 420 421 bool RegisterContext::ReadAllRegisterValues( 422 lldb_private::RegisterCheckpoint ®_checkpoint) { 423 return ReadAllRegisterValues(reg_checkpoint.GetData()); 424 } 425 426 bool RegisterContext::WriteAllRegisterValues( 427 const lldb_private::RegisterCheckpoint ®_checkpoint) { 428 return WriteAllRegisterValues(reg_checkpoint.GetData()); 429 } 430 431 TargetSP RegisterContext::CalculateTarget() { 432 return m_thread.CalculateTarget(); 433 } 434 435 ProcessSP RegisterContext::CalculateProcess() { 436 return m_thread.CalculateProcess(); 437 } 438 439 ThreadSP RegisterContext::CalculateThread() { 440 return m_thread.shared_from_this(); 441 } 442 443 StackFrameSP RegisterContext::CalculateStackFrame() { 444 // Register contexts might belong to many frames if we have inlined functions 445 // inside a frame since all inlined functions share the same registers, so we 446 // can't definitively say which frame we come from... 447 return StackFrameSP(); 448 } 449 450 void RegisterContext::CalculateExecutionContext(ExecutionContext &exe_ctx) { 451 m_thread.CalculateExecutionContext(exe_ctx); 452 } 453 454 bool RegisterContext::ConvertBetweenRegisterKinds(lldb::RegisterKind source_rk, 455 uint32_t source_regnum, 456 lldb::RegisterKind target_rk, 457 uint32_t &target_regnum) { 458 const uint32_t num_registers = GetRegisterCount(); 459 for (uint32_t reg = 0; reg < num_registers; ++reg) { 460 const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg); 461 462 if (reg_info->kinds[source_rk] == source_regnum) { 463 target_regnum = reg_info->kinds[target_rk]; 464 return (target_regnum != LLDB_INVALID_REGNUM); 465 } 466 } 467 return false; 468 } 469