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
23using namespace lldb;
24using namespace lldb_private;
25
26RegisterContext::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
30RegisterContext::~RegisterContext() = default;
31
32void 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
51const RegisterInfo *
52RegisterContext::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(s: reg_name);
61 if (generic_reg != LLDB_INVALID_REGNUM) {
62 const RegisterInfo *reg_info =
63 GetRegisterInfo(reg_kind: eRegisterKindGeneric, reg_num: 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(RHS: reg_info->name) ||
73 reg_name.equals_insensitive(RHS: reg_info->alt_name))
74 return reg_info;
75 }
76
77 return nullptr;
78}
79
80const 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: reg_num);
86}
87
88const 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
95uint64_t RegisterContext::GetPC(uint64_t fail_value) {
96 uint32_t reg = ConvertRegisterKindToRegisterNumber(kind: 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(load_addr: pc, addr_class: AddressClass::eCode);
106 }
107 }
108
109 return pc;
110}
111
112uint64_t RegisterContext::GetThreadPointer(uint64_t fail_value) {
113 uint32_t reg = ConvertRegisterKindToRegisterNumber(kind: eRegisterKindGeneric,
114 LLDB_REGNUM_GENERIC_TP);
115 return ReadRegisterAsUnsigned(reg, fail_value);
116}
117
118bool RegisterContext::SetPC(uint64_t pc) {
119 uint32_t reg = ConvertRegisterKindToRegisterNumber(kind: eRegisterKindGeneric,
120 LLDB_REGNUM_GENERIC_PC);
121 bool success = WriteRegisterFromUnsigned(reg, uval: pc);
122 if (success) {
123 StackFrameSP frame_sp(
124 m_thread.GetFrameWithConcreteFrameIndex(unwind_idx: m_concrete_frame_idx));
125 if (frame_sp)
126 frame_sp->ChangePC(pc);
127 else
128 m_thread.ClearStackFrames();
129 }
130 return success;
131}
132
133bool RegisterContext::GetPCForSymbolication(Address &address) {
134 addr_t pc = GetPC(LLDB_INVALID_ADDRESS);
135 if (pc == LLDB_INVALID_ADDRESS)
136 return false;
137 TargetSP target_sp = m_thread.CalculateTarget();
138 if (!target_sp.get())
139 return false;
140
141 if (!BehavesLikeZerothFrame() && pc != 0)
142 pc--;
143 address.SetLoadAddress(load_addr: pc, target: target_sp.get());
144 return true;
145}
146
147bool RegisterContext::SetPC(Address addr) {
148 TargetSP target_sp = m_thread.CalculateTarget();
149 Target *target = target_sp.get();
150
151 lldb::addr_t callAddr = addr.GetCallableLoadAddress(target);
152 if (callAddr == LLDB_INVALID_ADDRESS)
153 return false;
154
155 return SetPC(callAddr);
156}
157
158uint64_t RegisterContext::GetSP(uint64_t fail_value) {
159 uint32_t reg = ConvertRegisterKindToRegisterNumber(kind: eRegisterKindGeneric,
160 LLDB_REGNUM_GENERIC_SP);
161 return ReadRegisterAsUnsigned(reg, fail_value);
162}
163
164bool RegisterContext::SetSP(uint64_t sp) {
165 uint32_t reg = ConvertRegisterKindToRegisterNumber(kind: eRegisterKindGeneric,
166 LLDB_REGNUM_GENERIC_SP);
167 return WriteRegisterFromUnsigned(reg, uval: sp);
168}
169
170uint64_t RegisterContext::GetFP(uint64_t fail_value) {
171 uint32_t reg = ConvertRegisterKindToRegisterNumber(kind: eRegisterKindGeneric,
172 LLDB_REGNUM_GENERIC_FP);
173 return ReadRegisterAsUnsigned(reg, fail_value);
174}
175
176bool RegisterContext::SetFP(uint64_t fp) {
177 uint32_t reg = ConvertRegisterKindToRegisterNumber(kind: eRegisterKindGeneric,
178 LLDB_REGNUM_GENERIC_FP);
179 return WriteRegisterFromUnsigned(reg, uval: fp);
180}
181
182uint64_t RegisterContext::GetReturnAddress(uint64_t fail_value) {
183 uint32_t reg = ConvertRegisterKindToRegisterNumber(kind: eRegisterKindGeneric,
184 LLDB_REGNUM_GENERIC_RA);
185 return ReadRegisterAsUnsigned(reg, fail_value);
186}
187
188uint64_t RegisterContext::GetFlags(uint64_t fail_value) {
189 uint32_t reg = ConvertRegisterKindToRegisterNumber(kind: eRegisterKindGeneric,
190 LLDB_REGNUM_GENERIC_FLAGS);
191 return ReadRegisterAsUnsigned(reg, fail_value);
192}
193
194uint64_t RegisterContext::ReadRegisterAsUnsigned(uint32_t reg,
195 uint64_t fail_value) {
196 if (reg != LLDB_INVALID_REGNUM)
197 return ReadRegisterAsUnsigned(reg_info: GetRegisterInfoAtIndex(reg), fail_value);
198 return fail_value;
199}
200
201uint64_t RegisterContext::ReadRegisterAsUnsigned(const RegisterInfo *reg_info,
202 uint64_t fail_value) {
203 if (reg_info) {
204 RegisterValue value;
205 if (ReadRegister(reg_info, reg_value&: value))
206 return value.GetAsUInt64();
207 }
208 return fail_value;
209}
210
211bool RegisterContext::WriteRegisterFromUnsigned(uint32_t reg, uint64_t uval) {
212 if (reg == LLDB_INVALID_REGNUM)
213 return false;
214 return WriteRegisterFromUnsigned(reg_info: GetRegisterInfoAtIndex(reg), uval);
215}
216
217bool RegisterContext::WriteRegisterFromUnsigned(const RegisterInfo *reg_info,
218 uint64_t uval) {
219 if (reg_info) {
220 RegisterValue value;
221 if (value.SetUInt(uint: uval, byte_size: reg_info->byte_size))
222 return WriteRegister(reg_info, reg_value: value);
223 }
224 return false;
225}
226
227bool RegisterContext::CopyFromRegisterContext(lldb::RegisterContextSP context) {
228 uint32_t num_register_sets = context->GetRegisterSetCount();
229 // We don't know that two threads have the same register context, so require
230 // the threads to be the same.
231 if (context->GetThreadID() != GetThreadID())
232 return false;
233
234 if (num_register_sets != GetRegisterSetCount())
235 return false;
236
237 RegisterContextSP frame_zero_context = m_thread.GetRegisterContext();
238
239 for (uint32_t set_idx = 0; set_idx < num_register_sets; ++set_idx) {
240 const RegisterSet *const reg_set = GetRegisterSet(reg_set: set_idx);
241
242 const uint32_t num_registers = reg_set->num_registers;
243 for (uint32_t reg_idx = 0; reg_idx < num_registers; ++reg_idx) {
244 const uint32_t reg = reg_set->registers[reg_idx];
245 const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg);
246 if (!reg_info || reg_info->value_regs)
247 continue;
248 RegisterValue reg_value;
249
250 // If we can reconstruct the register from the frame we are copying from,
251 // then do so, otherwise use the value from frame 0.
252 if (context->ReadRegister(reg_info, reg_value)) {
253 WriteRegister(reg_info, reg_value);
254 } else if (frame_zero_context->ReadRegister(reg_info, reg_value)) {
255 WriteRegister(reg_info, reg_value);
256 }
257 }
258 }
259 return true;
260}
261
262lldb::tid_t RegisterContext::GetThreadID() const { return m_thread.GetID(); }
263
264uint32_t RegisterContext::NumSupportedHardwareBreakpoints() { return 0; }
265
266uint32_t RegisterContext::SetHardwareBreakpoint(lldb::addr_t addr,
267 size_t size) {
268 return LLDB_INVALID_INDEX32;
269}
270
271// Used when parsing DWARF and EH frame information and any other object file
272// sections that contain register numbers in them.
273uint32_t
274RegisterContext::ConvertRegisterKindToRegisterNumber(lldb::RegisterKind kind,
275 uint32_t num) {
276 const uint32_t num_regs = GetRegisterCount();
277
278 assert(kind < kNumRegisterKinds);
279 for (uint32_t reg_idx = 0; reg_idx < num_regs; ++reg_idx) {
280 const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg: reg_idx);
281
282 if (reg_info->kinds[kind] == num)
283 return reg_idx;
284 }
285
286 return LLDB_INVALID_REGNUM;
287}
288
289bool RegisterContext::ClearHardwareBreakpoint(uint32_t hw_idx) { return false; }
290
291uint32_t RegisterContext::NumSupportedHardwareWatchpoints() { return 0; }
292
293uint32_t RegisterContext::SetHardwareWatchpoint(lldb::addr_t addr, size_t size,
294 bool read, bool write) {
295 return LLDB_INVALID_INDEX32;
296}
297
298bool RegisterContext::ClearHardwareWatchpoint(uint32_t hw_index) {
299 return false;
300}
301
302bool RegisterContext::HardwareSingleStep(bool enable) { return false; }
303
304Status RegisterContext::ReadRegisterValueFromMemory(
305 const RegisterInfo *reg_info, lldb::addr_t src_addr, uint32_t src_len,
306 RegisterValue &reg_value) {
307 Status error;
308 if (reg_info == nullptr) {
309 error.SetErrorString("invalid register info argument.");
310 return error;
311 }
312
313 // Moving from addr into a register
314 //
315 // Case 1: src_len == dst_len
316 //
317 // |AABBCCDD| Address contents
318 // |AABBCCDD| Register contents
319 //
320 // Case 2: src_len > dst_len
321 //
322 // Status! (The register should always be big enough to hold the data)
323 //
324 // Case 3: src_len < dst_len
325 //
326 // |AABB| Address contents
327 // |AABB0000| Register contents [on little-endian hardware]
328 // |0000AABB| Register contents [on big-endian hardware]
329 const uint32_t dst_len = reg_info->byte_size;
330
331 if (src_len > dst_len) {
332 error.SetErrorStringWithFormat(
333 "%u bytes is too big to store in register %s (%u bytes)", src_len,
334 reg_info->name, dst_len);
335 return error;
336 }
337
338 ProcessSP process_sp(m_thread.GetProcess());
339 if (process_sp) {
340 RegisterValue::BytesContainer src(src_len);
341
342 // Read the memory
343 const uint32_t bytes_read =
344 process_sp->ReadMemory(vm_addr: src_addr, buf: src.data(), size: src_len, error);
345
346 // Make sure the memory read succeeded...
347 if (bytes_read != src_len) {
348 if (error.Success()) {
349 // This might happen if we read _some_ bytes but not all
350 error.SetErrorStringWithFormat("read %u of %u bytes", bytes_read,
351 src_len);
352 }
353 return error;
354 }
355
356 // We now have a memory buffer that contains the part or all of the
357 // register value. Set the register value using this memory data.
358 // TODO: we might need to add a parameter to this function in case the byte
359 // order of the memory data doesn't match the process. For now we are
360 // assuming they are the same.
361 reg_value.SetFromMemoryData(reg_info: *reg_info, src: src.data(), src_len,
362 src_byte_order: process_sp->GetByteOrder(), error);
363 } else
364 error.SetErrorString("invalid process");
365
366 return error;
367}
368
369Status RegisterContext::WriteRegisterValueToMemory(
370 const RegisterInfo *reg_info, lldb::addr_t dst_addr, uint32_t dst_len,
371 const RegisterValue &reg_value) {
372 Status error;
373 ProcessSP process_sp(m_thread.GetProcess());
374
375 if (!process_sp) {
376 error.SetErrorString("invalid process");
377 return error;
378 }
379
380 if (reg_info == nullptr) {
381 error.SetErrorString("Invalid register info argument.");
382 return error;
383 }
384
385 // TODO: we might need to add a parameter to this function in case the byte
386 // order of the memory data doesn't match the process. For now we are
387 // assuming they are the same.
388 RegisterValue::BytesContainer dst(dst_len);
389 const uint32_t bytes_copied = reg_value.GetAsMemoryData(
390 reg_info: *reg_info, dst: dst.data(), dst_len, dst_byte_order: process_sp->GetByteOrder(), error);
391
392 if (error.Success()) {
393 if (bytes_copied == 0) {
394 error.SetErrorString("byte copy failed.");
395 } else {
396 const uint32_t bytes_written =
397 process_sp->WriteMemory(vm_addr: dst_addr, buf: dst.data(), size: bytes_copied, error);
398 if (bytes_written != bytes_copied) {
399 if (error.Success()) {
400 // This might happen if we read _some_ bytes but not all
401 error.SetErrorStringWithFormat("only wrote %u of %u bytes",
402 bytes_written, bytes_copied);
403 }
404 }
405 }
406 }
407
408 return error;
409}
410
411lldb::ByteOrder RegisterContext::GetByteOrder() {
412 // Get the target process whose privileged thread was used for the register
413 // read.
414 lldb::ByteOrder byte_order = lldb::eByteOrderInvalid;
415 lldb_private::Process *process = CalculateProcess().get();
416
417 if (process)
418 byte_order = process->GetByteOrder();
419 return byte_order;
420}
421
422bool RegisterContext::ReadAllRegisterValues(
423 lldb_private::RegisterCheckpoint &reg_checkpoint) {
424 return ReadAllRegisterValues(data_sp&: reg_checkpoint.GetData());
425}
426
427bool RegisterContext::WriteAllRegisterValues(
428 const lldb_private::RegisterCheckpoint &reg_checkpoint) {
429 return WriteAllRegisterValues(data_sp: reg_checkpoint.GetData());
430}
431
432TargetSP RegisterContext::CalculateTarget() {
433 return m_thread.CalculateTarget();
434}
435
436ProcessSP RegisterContext::CalculateProcess() {
437 return m_thread.CalculateProcess();
438}
439
440ThreadSP RegisterContext::CalculateThread() {
441 return m_thread.shared_from_this();
442}
443
444StackFrameSP RegisterContext::CalculateStackFrame() {
445 // Register contexts might belong to many frames if we have inlined functions
446 // inside a frame since all inlined functions share the same registers, so we
447 // can't definitively say which frame we come from...
448 return StackFrameSP();
449}
450
451void RegisterContext::CalculateExecutionContext(ExecutionContext &exe_ctx) {
452 m_thread.CalculateExecutionContext(exe_ctx);
453}
454
455bool RegisterContext::ConvertBetweenRegisterKinds(lldb::RegisterKind source_rk,
456 uint32_t source_regnum,
457 lldb::RegisterKind target_rk,
458 uint32_t &target_regnum) {
459 const uint32_t num_registers = GetRegisterCount();
460 for (uint32_t reg = 0; reg < num_registers; ++reg) {
461 const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg);
462
463 if (reg_info->kinds[source_rk] == source_regnum) {
464 target_regnum = reg_info->kinds[target_rk];
465 return (target_regnum != LLDB_INVALID_REGNUM);
466 }
467 }
468 return false;
469}
470

source code of lldb/source/Target/RegisterContext.cpp