1 //===-- RegisterContext.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/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 const uint32_t num_registers = GetRegisterCount(); 58 for (uint32_t reg = start_idx; reg < num_registers; ++reg) { 59 const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg); 60 61 if (reg_name.equals_lower(reg_info->name) || 62 reg_name.equals_lower(reg_info->alt_name)) 63 return reg_info; 64 } 65 return nullptr; 66 } 67 68 uint32_t 69 RegisterContext::UpdateDynamicRegisterSize(const lldb_private::ArchSpec &arch, 70 RegisterInfo *reg_info) { 71 ExecutionContext exe_ctx(CalculateThread()); 72 73 // In MIPS, the floating point registers size is depends on FR bit of SR 74 // register. if SR.FR == 1 then all floating point registers are 64 bits. 75 // else they are all 32 bits. 76 77 int expr_result; 78 uint32_t addr_size = arch.GetAddressByteSize(); 79 const uint8_t *dwarf_opcode_ptr = reg_info->dynamic_size_dwarf_expr_bytes; 80 const size_t dwarf_opcode_len = reg_info->dynamic_size_dwarf_len; 81 82 DataExtractor dwarf_data(dwarf_opcode_ptr, dwarf_opcode_len, 83 arch.GetByteOrder(), addr_size); 84 ModuleSP opcode_ctx; 85 DWARFExpression dwarf_expr(opcode_ctx, dwarf_data, nullptr); 86 Value result; 87 Status error; 88 if (dwarf_expr.Evaluate(&exe_ctx, this, opcode_ctx, dwarf_data, nullptr, 89 eRegisterKindDWARF, nullptr, nullptr, result, 90 &error)) { 91 expr_result = result.GetScalar().SInt(-1); 92 switch (expr_result) { 93 case 0: 94 return 4; 95 case 1: 96 return 8; 97 default: 98 return reg_info->byte_size; 99 } 100 } else { 101 printf("Error executing DwarfExpression::Evaluate %s\n", error.AsCString()); 102 return reg_info->byte_size; 103 } 104 } 105 106 const RegisterInfo *RegisterContext::GetRegisterInfo(lldb::RegisterKind kind, 107 uint32_t num) { 108 const uint32_t reg_num = ConvertRegisterKindToRegisterNumber(kind, num); 109 if (reg_num == LLDB_INVALID_REGNUM) 110 return nullptr; 111 return GetRegisterInfoAtIndex(reg_num); 112 } 113 114 const char *RegisterContext::GetRegisterName(uint32_t reg) { 115 const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg); 116 if (reg_info) 117 return reg_info->name; 118 return nullptr; 119 } 120 121 uint64_t RegisterContext::GetPC(uint64_t fail_value) { 122 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 123 LLDB_REGNUM_GENERIC_PC); 124 uint64_t pc = ReadRegisterAsUnsigned(reg, fail_value); 125 126 if (pc != fail_value) { 127 TargetSP target_sp = m_thread.CalculateTarget(); 128 if (target_sp) { 129 Target *target = target_sp.get(); 130 if (target) 131 pc = target->GetOpcodeLoadAddress(pc, AddressClass::eCode); 132 } 133 } 134 135 return pc; 136 } 137 138 bool RegisterContext::SetPC(uint64_t pc) { 139 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 140 LLDB_REGNUM_GENERIC_PC); 141 bool success = WriteRegisterFromUnsigned(reg, pc); 142 if (success) { 143 StackFrameSP frame_sp( 144 m_thread.GetFrameWithConcreteFrameIndex(m_concrete_frame_idx)); 145 if (frame_sp) 146 frame_sp->ChangePC(pc); 147 else 148 m_thread.ClearStackFrames(); 149 } 150 return success; 151 } 152 153 bool RegisterContext::SetPC(Address addr) { 154 TargetSP target_sp = m_thread.CalculateTarget(); 155 Target *target = target_sp.get(); 156 157 lldb::addr_t callAddr = addr.GetCallableLoadAddress(target); 158 if (callAddr == LLDB_INVALID_ADDRESS) 159 return false; 160 161 return SetPC(callAddr); 162 } 163 164 uint64_t RegisterContext::GetSP(uint64_t fail_value) { 165 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 166 LLDB_REGNUM_GENERIC_SP); 167 return ReadRegisterAsUnsigned(reg, fail_value); 168 } 169 170 bool RegisterContext::SetSP(uint64_t sp) { 171 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 172 LLDB_REGNUM_GENERIC_SP); 173 return WriteRegisterFromUnsigned(reg, sp); 174 } 175 176 uint64_t RegisterContext::GetFP(uint64_t fail_value) { 177 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 178 LLDB_REGNUM_GENERIC_FP); 179 return ReadRegisterAsUnsigned(reg, fail_value); 180 } 181 182 bool RegisterContext::SetFP(uint64_t fp) { 183 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 184 LLDB_REGNUM_GENERIC_FP); 185 return WriteRegisterFromUnsigned(reg, fp); 186 } 187 188 uint64_t RegisterContext::GetReturnAddress(uint64_t fail_value) { 189 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 190 LLDB_REGNUM_GENERIC_RA); 191 return ReadRegisterAsUnsigned(reg, fail_value); 192 } 193 194 uint64_t RegisterContext::GetFlags(uint64_t fail_value) { 195 uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, 196 LLDB_REGNUM_GENERIC_FLAGS); 197 return ReadRegisterAsUnsigned(reg, fail_value); 198 } 199 200 uint64_t RegisterContext::ReadRegisterAsUnsigned(uint32_t reg, 201 uint64_t fail_value) { 202 if (reg != LLDB_INVALID_REGNUM) 203 return ReadRegisterAsUnsigned(GetRegisterInfoAtIndex(reg), fail_value); 204 return fail_value; 205 } 206 207 uint64_t RegisterContext::ReadRegisterAsUnsigned(const RegisterInfo *reg_info, 208 uint64_t fail_value) { 209 if (reg_info) { 210 RegisterValue value; 211 if (ReadRegister(reg_info, value)) 212 return value.GetAsUInt64(); 213 } 214 return fail_value; 215 } 216 217 bool RegisterContext::WriteRegisterFromUnsigned(uint32_t reg, uint64_t uval) { 218 if (reg == LLDB_INVALID_REGNUM) 219 return false; 220 return WriteRegisterFromUnsigned(GetRegisterInfoAtIndex(reg), uval); 221 } 222 223 bool RegisterContext::WriteRegisterFromUnsigned(const RegisterInfo *reg_info, 224 uint64_t uval) { 225 if (reg_info) { 226 RegisterValue value; 227 if (value.SetUInt(uval, reg_info->byte_size)) 228 return WriteRegister(reg_info, value); 229 } 230 return false; 231 } 232 233 bool RegisterContext::CopyFromRegisterContext(lldb::RegisterContextSP context) { 234 uint32_t num_register_sets = context->GetRegisterSetCount(); 235 // We don't know that two threads have the same register context, so require 236 // the threads to be the same. 237 if (context->GetThreadID() != GetThreadID()) 238 return false; 239 240 if (num_register_sets != GetRegisterSetCount()) 241 return false; 242 243 RegisterContextSP frame_zero_context = m_thread.GetRegisterContext(); 244 245 for (uint32_t set_idx = 0; set_idx < num_register_sets; ++set_idx) { 246 const RegisterSet *const reg_set = GetRegisterSet(set_idx); 247 248 const uint32_t num_registers = reg_set->num_registers; 249 for (uint32_t reg_idx = 0; reg_idx < num_registers; ++reg_idx) { 250 const uint32_t reg = reg_set->registers[reg_idx]; 251 const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg); 252 if (!reg_info || reg_info->value_regs) 253 continue; 254 RegisterValue reg_value; 255 256 // If we can reconstruct the register from the frame we are copying from, 257 // then do so, otherwise use the value from frame 0. 258 if (context->ReadRegister(reg_info, reg_value)) { 259 WriteRegister(reg_info, reg_value); 260 } else if (frame_zero_context->ReadRegister(reg_info, reg_value)) { 261 WriteRegister(reg_info, reg_value); 262 } 263 } 264 } 265 return true; 266 } 267 268 lldb::tid_t RegisterContext::GetThreadID() const { return m_thread.GetID(); } 269 270 uint32_t RegisterContext::NumSupportedHardwareBreakpoints() { return 0; } 271 272 uint32_t RegisterContext::SetHardwareBreakpoint(lldb::addr_t addr, 273 size_t size) { 274 return LLDB_INVALID_INDEX32; 275 } 276 277 bool RegisterContext::ClearHardwareBreakpoint(uint32_t hw_idx) { return false; } 278 279 uint32_t RegisterContext::NumSupportedHardwareWatchpoints() { return 0; } 280 281 uint32_t RegisterContext::SetHardwareWatchpoint(lldb::addr_t addr, size_t size, 282 bool read, bool write) { 283 return LLDB_INVALID_INDEX32; 284 } 285 286 bool RegisterContext::ClearHardwareWatchpoint(uint32_t hw_index) { 287 return false; 288 } 289 290 bool RegisterContext::HardwareSingleStep(bool enable) { return false; } 291 292 Status RegisterContext::ReadRegisterValueFromMemory( 293 const RegisterInfo *reg_info, lldb::addr_t src_addr, uint32_t src_len, 294 RegisterValue ®_value) { 295 Status error; 296 if (reg_info == nullptr) { 297 error.SetErrorString("invalid register info argument."); 298 return error; 299 } 300 301 // Moving from addr into a register 302 // 303 // Case 1: src_len == dst_len 304 // 305 // |AABBCCDD| Address contents 306 // |AABBCCDD| Register contents 307 // 308 // Case 2: src_len > dst_len 309 // 310 // Status! (The register should always be big enough to hold the data) 311 // 312 // Case 3: src_len < dst_len 313 // 314 // |AABB| Address contents 315 // |AABB0000| Register contents [on little-endian hardware] 316 // |0000AABB| Register contents [on big-endian hardware] 317 if (src_len > RegisterValue::kMaxRegisterByteSize) { 318 error.SetErrorString("register too small to receive memory data"); 319 return error; 320 } 321 322 const uint32_t dst_len = reg_info->byte_size; 323 324 if (src_len > dst_len) { 325 error.SetErrorStringWithFormat( 326 "%u bytes is too big to store in register %s (%u bytes)", src_len, 327 reg_info->name, dst_len); 328 return error; 329 } 330 331 ProcessSP process_sp(m_thread.GetProcess()); 332 if (process_sp) { 333 uint8_t src[RegisterValue::kMaxRegisterByteSize]; 334 335 // Read the memory 336 const uint32_t bytes_read = 337 process_sp->ReadMemory(src_addr, src, src_len, error); 338 339 // Make sure the memory read succeeded... 340 if (bytes_read != src_len) { 341 if (error.Success()) { 342 // This might happen if we read _some_ bytes but not all 343 error.SetErrorStringWithFormat("read %u of %u bytes", bytes_read, 344 src_len); 345 } 346 return error; 347 } 348 349 // We now have a memory buffer that contains the part or all of the 350 // register value. Set the register value using this memory data. 351 // TODO: we might need to add a parameter to this function in case the byte 352 // order of the memory data doesn't match the process. For now we are 353 // assuming they are the same. 354 reg_value.SetFromMemoryData(reg_info, src, src_len, 355 process_sp->GetByteOrder(), error); 356 } else 357 error.SetErrorString("invalid process"); 358 359 return error; 360 } 361 362 Status RegisterContext::WriteRegisterValueToMemory( 363 const RegisterInfo *reg_info, lldb::addr_t dst_addr, uint32_t dst_len, 364 const RegisterValue ®_value) { 365 uint8_t dst[RegisterValue::kMaxRegisterByteSize]; 366 367 Status error; 368 369 ProcessSP process_sp(m_thread.GetProcess()); 370 if (process_sp) { 371 372 // TODO: we might need to add a parameter to this function in case the byte 373 // order of the memory data doesn't match the process. For now we are 374 // assuming they are the same. 375 376 const uint32_t bytes_copied = reg_value.GetAsMemoryData( 377 reg_info, dst, dst_len, process_sp->GetByteOrder(), error); 378 379 if (error.Success()) { 380 if (bytes_copied == 0) { 381 error.SetErrorString("byte copy failed."); 382 } else { 383 const uint32_t bytes_written = 384 process_sp->WriteMemory(dst_addr, dst, bytes_copied, error); 385 if (bytes_written != bytes_copied) { 386 if (error.Success()) { 387 // This might happen if we read _some_ bytes but not all 388 error.SetErrorStringWithFormat("only wrote %u of %u bytes", 389 bytes_written, bytes_copied); 390 } 391 } 392 } 393 } 394 } else 395 error.SetErrorString("invalid process"); 396 397 return error; 398 } 399 400 bool RegisterContext::ReadAllRegisterValues( 401 lldb_private::RegisterCheckpoint ®_checkpoint) { 402 return ReadAllRegisterValues(reg_checkpoint.GetData()); 403 } 404 405 bool RegisterContext::WriteAllRegisterValues( 406 const lldb_private::RegisterCheckpoint ®_checkpoint) { 407 return WriteAllRegisterValues(reg_checkpoint.GetData()); 408 } 409 410 TargetSP RegisterContext::CalculateTarget() { 411 return m_thread.CalculateTarget(); 412 } 413 414 ProcessSP RegisterContext::CalculateProcess() { 415 return m_thread.CalculateProcess(); 416 } 417 418 ThreadSP RegisterContext::CalculateThread() { 419 return m_thread.shared_from_this(); 420 } 421 422 StackFrameSP RegisterContext::CalculateStackFrame() { 423 // Register contexts might belong to many frames if we have inlined functions 424 // inside a frame since all inlined functions share the same registers, so we 425 // can't definitively say which frame we come from... 426 return StackFrameSP(); 427 } 428 429 void RegisterContext::CalculateExecutionContext(ExecutionContext &exe_ctx) { 430 m_thread.CalculateExecutionContext(exe_ctx); 431 } 432 433 bool RegisterContext::ConvertBetweenRegisterKinds(lldb::RegisterKind source_rk, 434 uint32_t source_regnum, 435 lldb::RegisterKind target_rk, 436 uint32_t &target_regnum) { 437 const uint32_t num_registers = GetRegisterCount(); 438 for (uint32_t reg = 0; reg < num_registers; ++reg) { 439 const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg); 440 441 if (reg_info->kinds[source_rk] == source_regnum) { 442 target_regnum = reg_info->kinds[target_rk]; 443 return (target_regnum != LLDB_INVALID_REGNUM); 444 } 445 } 446 return false; 447 } 448