1//===-- ABISysV_arm64.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 "ABISysV_arm64.h"
10
11#include <optional>
12#include <vector>
13
14#include "llvm/ADT/STLExtras.h"
15#include "llvm/TargetParser/Triple.h"
16
17#include "lldb/Core/Module.h"
18#include "lldb/Core/PluginManager.h"
19#include "lldb/Core/Value.h"
20#include "lldb/Symbol/UnwindPlan.h"
21#include "lldb/Target/Process.h"
22#include "lldb/Target/RegisterContext.h"
23#include "lldb/Target/Target.h"
24#include "lldb/Target/Thread.h"
25#include "lldb/Utility/ConstString.h"
26#include "lldb/Utility/LLDBLog.h"
27#include "lldb/Utility/Log.h"
28#include "lldb/Utility/RegisterValue.h"
29#include "lldb/Utility/Scalar.h"
30#include "lldb/Utility/Status.h"
31#include "lldb/ValueObject/ValueObjectConstResult.h"
32
33using namespace lldb;
34using namespace lldb_private;
35
36bool ABISysV_arm64::GetPointerReturnRegister(const char *&name) {
37 name = "x0";
38 return true;
39}
40
41size_t ABISysV_arm64::GetRedZoneSize() const { return 128; }
42
43// Static Functions
44
45ABISP
46ABISysV_arm64::CreateInstance(lldb::ProcessSP process_sp, const ArchSpec &arch) {
47 const llvm::Triple::ArchType arch_type = arch.GetTriple().getArch();
48 const llvm::Triple::VendorType vendor_type = arch.GetTriple().getVendor();
49
50 if (vendor_type != llvm::Triple::Apple) {
51 if (arch_type == llvm::Triple::aarch64 ||
52 arch_type == llvm::Triple::aarch64_32) {
53 return ABISP(
54 new ABISysV_arm64(std::move(process_sp), MakeMCRegisterInfo(arch)));
55 }
56 }
57
58 return ABISP();
59}
60
61static Status PushToLinuxGuardedControlStack(addr_t return_addr,
62 RegisterContext *reg_ctx,
63 Thread &thread) {
64 Status err;
65
66 // If the Guarded Control Stack extension is present we may need to put the
67 // return address onto that stack.
68 const RegisterInfo *gcs_features_enabled_info =
69 reg_ctx->GetRegisterInfoByName(reg_name: "gcs_features_enabled");
70 if (!gcs_features_enabled_info)
71 return err;
72
73 uint64_t gcs_features_enabled = reg_ctx->ReadRegisterAsUnsigned(
74 reg_info: gcs_features_enabled_info, LLDB_INVALID_ADDRESS);
75 if (gcs_features_enabled == LLDB_INVALID_ADDRESS)
76 return Status("Could not read GCS features enabled register.");
77
78 // Only attempt this if GCS is enabled. If it's not enabled then gcspr_el0
79 // may point to unmapped memory.
80 if ((gcs_features_enabled & 1) == 0)
81 return err;
82
83 const RegisterInfo *gcspr_el0_info =
84 reg_ctx->GetRegisterInfoByName(reg_name: "gcspr_el0");
85 if (!gcspr_el0_info)
86 return Status("Could not get register info for gcspr_el0.");
87
88 uint64_t gcspr_el0 =
89 reg_ctx->ReadRegisterAsUnsigned(reg_info: gcspr_el0_info, LLDB_INVALID_ADDRESS);
90 if (gcspr_el0 == LLDB_INVALID_ADDRESS)
91 return Status("Could not read gcspr_el0.");
92
93 // A link register entry on the GCS is 8 bytes.
94 gcspr_el0 -= 8;
95 if (!reg_ctx->WriteRegisterFromUnsigned(reg_info: gcspr_el0_info, uval: gcspr_el0))
96 return Status(
97 "Attempted to decrement gcspr_el0, but could not write to it.");
98
99 Status error;
100 size_t wrote = thread.GetProcess()->WriteMemory(vm_addr: gcspr_el0, buf: &return_addr,
101 size: sizeof(return_addr), error);
102 if ((wrote != sizeof(return_addr) || error.Fail())) {
103 // gcspr_el0 will be restored by the ThreadPlan's DoTakedown.
104 return Status("Failed to write new Guarded Control Stack entry.");
105 }
106
107 Log *log = GetLog(mask: LLDBLog::Expressions);
108 LLDB_LOGF(log,
109 "Pushed return address 0x%" PRIx64 " to Guarded Control Stack. "
110 "gcspr_el0 was 0%" PRIx64 ", is now 0x%" PRIx64 ".",
111 return_addr, gcspr_el0 - 8, gcspr_el0);
112
113 // gcspr_el0 will be restored to the original value by lldb-server after
114 // the call has finished, which serves as the "pop".
115
116 return err;
117}
118
119bool ABISysV_arm64::PrepareTrivialCall(Thread &thread, addr_t sp,
120 addr_t func_addr, addr_t return_addr,
121 llvm::ArrayRef<addr_t> args) const {
122 RegisterContext *reg_ctx = thread.GetRegisterContext().get();
123 if (!reg_ctx)
124 return false;
125
126 Log *log = GetLog(mask: LLDBLog::Expressions);
127
128 if (log) {
129 StreamString s;
130 s.Printf(format: "ABISysV_arm64::PrepareTrivialCall (tid = 0x%" PRIx64
131 ", sp = 0x%" PRIx64 ", func_addr = 0x%" PRIx64
132 ", return_addr = 0x%" PRIx64,
133 thread.GetID(), (uint64_t)sp, (uint64_t)func_addr,
134 (uint64_t)return_addr);
135
136 for (size_t i = 0; i < args.size(); ++i)
137 s.Printf(format: ", arg%d = 0x%" PRIx64, static_cast<int>(i + 1), args[i]);
138 s.PutCString(cstr: ")");
139 log->PutString(str: s.GetString());
140 }
141
142 // x0 - x7 contain first 8 simple args
143 if (args.size() > 8)
144 return false;
145
146 if (GetProcessSP()->GetTarget().GetArchitecture().GetTriple().isOSLinux()) {
147 Status err = PushToLinuxGuardedControlStack(return_addr, reg_ctx, thread);
148 // If we could not manage the GCS, the expression will certainly fail,
149 // and if we just carried on, that failure would be a lot more cryptic.
150 if (err.Fail()) {
151 LLDB_LOGF(log, "Failed to setup Guarded Call Stack: %s", err.AsCString());
152 return false;
153 }
154 }
155
156 for (size_t i = 0; i < args.size(); ++i) {
157 const RegisterInfo *reg_info = reg_ctx->GetRegisterInfo(
158 reg_kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG1 + i);
159 LLDB_LOGF(log, "About to write arg%d (0x%" PRIx64 ") into %s",
160 static_cast<int>(i + 1), args[i], reg_info->name);
161 if (!reg_ctx->WriteRegisterFromUnsigned(reg_info, uval: args[i]))
162 return false;
163 }
164
165 // Set "lr" to the return address
166 if (!reg_ctx->WriteRegisterFromUnsigned(
167 reg_info: reg_ctx->GetRegisterInfo(reg_kind: eRegisterKindGeneric,
168 LLDB_REGNUM_GENERIC_RA),
169 uval: return_addr))
170 return false;
171
172 // Set "sp" to the requested value
173 if (!reg_ctx->WriteRegisterFromUnsigned(
174 reg_info: reg_ctx->GetRegisterInfo(reg_kind: eRegisterKindGeneric,
175 LLDB_REGNUM_GENERIC_SP),
176 uval: sp))
177 return false;
178
179 // Set "pc" to the address requested
180 if (!reg_ctx->WriteRegisterFromUnsigned(
181 reg_info: reg_ctx->GetRegisterInfo(reg_kind: eRegisterKindGeneric,
182 LLDB_REGNUM_GENERIC_PC),
183 uval: func_addr))
184 return false;
185
186 return true;
187}
188
189// TODO: We dont support fp/SIMD arguments in v0-v7
190bool ABISysV_arm64::GetArgumentValues(Thread &thread, ValueList &values) const {
191 uint32_t num_values = values.GetSize();
192
193 ExecutionContext exe_ctx(thread.shared_from_this());
194
195 // Extract the register context so we can read arguments from registers
196
197 RegisterContext *reg_ctx = thread.GetRegisterContext().get();
198
199 if (!reg_ctx)
200 return false;
201
202 addr_t sp = 0;
203
204 for (uint32_t value_idx = 0; value_idx < num_values; ++value_idx) {
205 // We currently only support extracting values with Clang QualTypes. Do we
206 // care about others?
207 Value *value = values.GetValueAtIndex(idx: value_idx);
208
209 if (!value)
210 return false;
211
212 CompilerType value_type = value->GetCompilerType();
213 if (value_type) {
214 bool is_signed = false;
215 size_t bit_width = 0;
216 std::optional<uint64_t> bit_size =
217 llvm::expectedToOptional(E: value_type.GetBitSize(exe_scope: &thread));
218 if (!bit_size)
219 return false;
220 if (value_type.IsIntegerOrEnumerationType(is_signed)) {
221 bit_width = *bit_size;
222 } else if (value_type.IsPointerOrReferenceType()) {
223 bit_width = *bit_size;
224 } else {
225 // We only handle integer, pointer and reference types currently...
226 return false;
227 }
228
229 if (bit_width <= (exe_ctx.GetProcessRef().GetAddressByteSize() * 8)) {
230 if (value_idx < 8) {
231 // Arguments 1-8 are in x0-x7...
232 const RegisterInfo *reg_info = nullptr;
233 reg_info = reg_ctx->GetRegisterInfo(
234 reg_kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG1 + value_idx);
235
236 if (reg_info) {
237 RegisterValue reg_value;
238
239 if (reg_ctx->ReadRegister(reg_info, reg_value)) {
240 if (is_signed)
241 reg_value.SignExtend(sign_bitpos: bit_width);
242 if (!reg_value.GetScalarValue(scalar&: value->GetScalar()))
243 return false;
244 continue;
245 }
246 }
247 return false;
248 } else {
249 // TODO: Verify for stack layout for SysV
250 if (sp == 0) {
251 // Read the stack pointer if we already haven't read it
252 sp = reg_ctx->GetSP(fail_value: 0);
253 if (sp == 0)
254 return false;
255 }
256
257 // Arguments 5 on up are on the stack
258 const uint32_t arg_byte_size = (bit_width + (8 - 1)) / 8;
259 Status error;
260 if (!exe_ctx.GetProcessRef().ReadScalarIntegerFromMemory(
261 addr: sp, byte_size: arg_byte_size, is_signed, scalar&: value->GetScalar(), error))
262 return false;
263
264 sp += arg_byte_size;
265 // Align up to the next 8 byte boundary if needed
266 if (sp % 8) {
267 sp >>= 3;
268 sp += 1;
269 sp <<= 3;
270 }
271 }
272 }
273 }
274 }
275 return true;
276}
277
278Status ABISysV_arm64::SetReturnValueObject(lldb::StackFrameSP &frame_sp,
279 lldb::ValueObjectSP &new_value_sp) {
280 Status error;
281 if (!new_value_sp) {
282 error = Status::FromErrorString(str: "Empty value object for return value.");
283 return error;
284 }
285
286 CompilerType return_value_type = new_value_sp->GetCompilerType();
287 if (!return_value_type) {
288 error = Status::FromErrorString(str: "Null clang type for return value.");
289 return error;
290 }
291
292 Thread *thread = frame_sp->GetThread().get();
293
294 RegisterContext *reg_ctx = thread->GetRegisterContext().get();
295
296 if (reg_ctx) {
297 DataExtractor data;
298 Status data_error;
299 const uint64_t byte_size = new_value_sp->GetData(data, error&: data_error);
300 if (data_error.Fail()) {
301 error = Status::FromErrorStringWithFormat(
302 format: "Couldn't convert return value to raw data: %s",
303 data_error.AsCString());
304 return error;
305 }
306
307 const uint32_t type_flags = return_value_type.GetTypeInfo(pointee_or_element_compiler_type: nullptr);
308 if (type_flags & eTypeIsScalar || type_flags & eTypeIsPointer) {
309 if (type_flags & eTypeIsInteger || type_flags & eTypeIsPointer) {
310 // Extract the register context so we can read arguments from registers
311 lldb::offset_t offset = 0;
312 if (byte_size <= 16) {
313 const RegisterInfo *x0_info = reg_ctx->GetRegisterInfo(
314 reg_kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG1);
315 if (byte_size <= 8) {
316 uint64_t raw_value = data.GetMaxU64(offset_ptr: &offset, byte_size);
317
318 if (!reg_ctx->WriteRegisterFromUnsigned(reg_info: x0_info, uval: raw_value))
319 error = Status::FromErrorString(str: "failed to write register x0");
320 } else {
321 uint64_t raw_value = data.GetMaxU64(offset_ptr: &offset, byte_size: 8);
322
323 if (reg_ctx->WriteRegisterFromUnsigned(reg_info: x0_info, uval: raw_value)) {
324 const RegisterInfo *x1_info = reg_ctx->GetRegisterInfo(
325 reg_kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG2);
326 raw_value = data.GetMaxU64(offset_ptr: &offset, byte_size: byte_size - offset);
327
328 if (!reg_ctx->WriteRegisterFromUnsigned(reg_info: x1_info, uval: raw_value))
329 error = Status::FromErrorString(str: "failed to write register x1");
330 }
331 }
332 } else {
333 error = Status::FromErrorString(
334 str: "We don't support returning longer than 128 bit "
335 "integer values at present.");
336 }
337 } else if (type_flags & eTypeIsFloat) {
338 if (type_flags & eTypeIsComplex) {
339 // Don't handle complex yet.
340 error = Status::FromErrorString(
341 str: "returning complex float values are not supported");
342 } else {
343 const RegisterInfo *v0_info = reg_ctx->GetRegisterInfoByName(reg_name: "v0", start_idx: 0);
344
345 if (v0_info) {
346 if (byte_size <= 16) {
347 RegisterValue reg_value;
348 error = reg_value.SetValueFromData(reg_info: *v0_info, data, offset: 0, partial_data_ok: true);
349 if (error.Success())
350 if (!reg_ctx->WriteRegister(reg_info: v0_info, reg_value))
351 error =
352 Status::FromErrorString(str: "failed to write register v0");
353 } else {
354 error = Status::FromErrorString(
355 str: "returning float values longer than 128 "
356 "bits are not supported");
357 }
358 } else
359 error = Status::FromErrorString(
360 str: "v0 register is not available on this target");
361 }
362 }
363 } else if (type_flags & eTypeIsVector) {
364 if (byte_size > 0) {
365 const RegisterInfo *v0_info = reg_ctx->GetRegisterInfoByName(reg_name: "v0", start_idx: 0);
366
367 if (v0_info) {
368 if (byte_size <= v0_info->byte_size) {
369 RegisterValue reg_value;
370 error = reg_value.SetValueFromData(reg_info: *v0_info, data, offset: 0, partial_data_ok: true);
371 if (error.Success()) {
372 if (!reg_ctx->WriteRegister(reg_info: v0_info, reg_value))
373 error = Status::FromErrorString(str: "failed to write register v0");
374 }
375 }
376 }
377 }
378 }
379 } else {
380 error = Status::FromErrorString(str: "no registers are available");
381 }
382
383 return error;
384}
385
386// AAPCS64 (Procedure Call Standard for the ARM 64-bit Architecture) says
387// registers x19 through x28 and sp are callee preserved. v8-v15 are non-
388// volatile (and specifically only the lower 8 bytes of these regs), the rest
389// of the fp/SIMD registers are volatile.
390
391// We treat x29 as callee preserved also, else the unwinder won't try to
392// retrieve fp saves.
393
394bool ABISysV_arm64::RegisterIsVolatile(const RegisterInfo *reg_info) {
395 if (reg_info) {
396 const char *name = reg_info->name;
397
398 // Sometimes we'll be called with the "alternate" name for these registers;
399 // recognize them as non-volatile.
400
401 if (name[0] == 'p' && name[1] == 'c') // pc
402 return false;
403 if (name[0] == 'f' && name[1] == 'p') // fp
404 return false;
405 if (name[0] == 's' && name[1] == 'p') // sp
406 return false;
407 if (name[0] == 'l' && name[1] == 'r') // lr
408 return false;
409
410 if (name[0] == 'x' || name[0] == 'r') {
411 // Volatile registers: x0-x18
412 // Although documentation says only x19-28 + sp are callee saved We ll
413 // also have to treat x30 as non-volatile. Each dwarf frame has its own
414 // value of lr. Return false for the non-volatile gpr regs, true for
415 // everything else
416 switch (name[1]) {
417 case '1':
418 switch (name[2]) {
419 case '9':
420 return false; // x19 is non-volatile
421 default:
422 return true;
423 }
424 break;
425 case '2':
426 switch (name[2]) {
427 case '0':
428 case '1':
429 case '2':
430 case '3':
431 case '4':
432 case '5':
433 case '6':
434 case '7':
435 case '8':
436 return false; // x20 - 28 are non-volatile
437 case '9':
438 return false; // x29 aka fp treat as non-volatile
439 default:
440 return true;
441 }
442 case '3': // x30 (lr) and x31 (sp) treat as non-volatile
443 if (name[2] == '0' || name[2] == '1')
444 return false;
445 break;
446 default:
447 return true; // all volatile cases not handled above fall here.
448 }
449 } else if (name[0] == 'v' || name[0] == 's' || name[0] == 'd') {
450 // Volatile registers: v0-7, v16-v31
451 // Return false for non-volatile fp/SIMD regs, true for everything else
452 switch (name[1]) {
453 case '8':
454 case '9':
455 return false; // v8-v9 are non-volatile
456 case '1':
457 switch (name[2]) {
458 case '0':
459 case '1':
460 case '2':
461 case '3':
462 case '4':
463 case '5':
464 return false; // v10-v15 are non-volatile
465 default:
466 return true;
467 }
468 default:
469 return true;
470 }
471 }
472 }
473 return true;
474}
475
476static bool LoadValueFromConsecutiveGPRRegisters(
477 ExecutionContext &exe_ctx, RegisterContext *reg_ctx,
478 const CompilerType &value_type,
479 bool is_return_value, // false => parameter, true => return value
480 uint32_t &NGRN, // NGRN (see ABI documentation)
481 uint32_t &NSRN, // NSRN (see ABI documentation)
482 DataExtractor &data) {
483 std::optional<uint64_t> byte_size = llvm::expectedToOptional(
484 E: value_type.GetByteSize(exe_scope: exe_ctx.GetBestExecutionContextScope()));
485
486 if (byte_size || *byte_size == 0)
487 return false;
488
489 std::unique_ptr<DataBufferHeap> heap_data_up(
490 new DataBufferHeap(*byte_size, 0));
491 const ByteOrder byte_order = exe_ctx.GetProcessRef().GetByteOrder();
492 Status error;
493
494 CompilerType base_type;
495 const uint32_t homogeneous_count =
496 value_type.IsHomogeneousAggregate(base_type_ptr: &base_type);
497 if (homogeneous_count > 0 && homogeneous_count <= 8) {
498 // Make sure we have enough registers
499 if (NSRN < 8 && (8 - NSRN) >= homogeneous_count) {
500 if (!base_type)
501 return false;
502 std::optional<uint64_t> base_byte_size = llvm::expectedToOptional(
503 E: base_type.GetByteSize(exe_scope: exe_ctx.GetBestExecutionContextScope()));
504 if (!base_byte_size)
505 return false;
506 uint32_t data_offset = 0;
507
508 for (uint32_t i = 0; i < homogeneous_count; ++i) {
509 char v_name[8];
510 ::snprintf(s: v_name, maxlen: sizeof(v_name), format: "v%u", NSRN);
511 const RegisterInfo *reg_info =
512 reg_ctx->GetRegisterInfoByName(reg_name: v_name, start_idx: 0);
513 if (reg_info == nullptr)
514 return false;
515
516 if (*base_byte_size > reg_info->byte_size)
517 return false;
518
519 RegisterValue reg_value;
520
521 if (!reg_ctx->ReadRegister(reg_info, reg_value))
522 return false;
523
524 // Make sure we have enough room in "heap_data_up"
525 if ((data_offset + *base_byte_size) <= heap_data_up->GetByteSize()) {
526 const size_t bytes_copied = reg_value.GetAsMemoryData(
527 reg_info: *reg_info, dst: heap_data_up->GetBytes() + data_offset,
528 dst_len: *base_byte_size, dst_byte_order: byte_order, error);
529 if (bytes_copied != *base_byte_size)
530 return false;
531 data_offset += bytes_copied;
532 ++NSRN;
533 } else
534 return false;
535 }
536 data.SetByteOrder(byte_order);
537 data.SetAddressByteSize(exe_ctx.GetProcessRef().GetAddressByteSize());
538 data.SetData(data_sp: DataBufferSP(heap_data_up.release()));
539 return true;
540 }
541 }
542
543 const size_t max_reg_byte_size = 16;
544 if (*byte_size <= max_reg_byte_size) {
545 size_t bytes_left = *byte_size;
546 uint32_t data_offset = 0;
547 while (data_offset < *byte_size) {
548 if (NGRN >= 8)
549 return false;
550
551 const RegisterInfo *reg_info = reg_ctx->GetRegisterInfo(
552 reg_kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG1 + NGRN);
553 if (reg_info == nullptr)
554 return false;
555
556 RegisterValue reg_value;
557
558 if (!reg_ctx->ReadRegister(reg_info, reg_value))
559 return false;
560
561 const size_t curr_byte_size = std::min<size_t>(a: 8, b: bytes_left);
562 const size_t bytes_copied = reg_value.GetAsMemoryData(
563 reg_info: *reg_info, dst: heap_data_up->GetBytes() + data_offset, dst_len: curr_byte_size,
564 dst_byte_order: byte_order, error);
565 if (bytes_copied == 0)
566 return false;
567 if (bytes_copied >= bytes_left)
568 break;
569 data_offset += bytes_copied;
570 bytes_left -= bytes_copied;
571 ++NGRN;
572 }
573 } else {
574 const RegisterInfo *reg_info = nullptr;
575 if (is_return_value) {
576 // The SysV arm64 ABI doesn't require you to write the return location
577 // back to x8 before returning from the function the way the x86_64 ABI
578 // does. It looks like all the users of this ABI currently choose not to
579 // do that, and so we can't reconstruct stack based returns on exit
580 // from the function.
581 return false;
582 } else {
583 // We are assuming we are stopped at the first instruction in a function
584 // and that the ABI is being respected so all parameters appear where
585 // they should be (functions with no external linkage can legally violate
586 // the ABI).
587 if (NGRN >= 8)
588 return false;
589
590 reg_info = reg_ctx->GetRegisterInfo(reg_kind: eRegisterKindGeneric,
591 LLDB_REGNUM_GENERIC_ARG1 + NGRN);
592 if (reg_info == nullptr)
593 return false;
594 ++NGRN;
595 }
596
597 const lldb::addr_t value_addr =
598 reg_ctx->ReadRegisterAsUnsigned(reg_info, LLDB_INVALID_ADDRESS);
599
600 if (value_addr == LLDB_INVALID_ADDRESS)
601 return false;
602
603 if (exe_ctx.GetProcessRef().ReadMemory(
604 vm_addr: value_addr, buf: heap_data_up->GetBytes(), size: heap_data_up->GetByteSize(),
605 error) != heap_data_up->GetByteSize()) {
606 return false;
607 }
608 }
609
610 data.SetByteOrder(byte_order);
611 data.SetAddressByteSize(exe_ctx.GetProcessRef().GetAddressByteSize());
612 data.SetData(data_sp: DataBufferSP(heap_data_up.release()));
613 return true;
614}
615
616ValueObjectSP ABISysV_arm64::GetReturnValueObjectImpl(
617 Thread &thread, CompilerType &return_compiler_type) const {
618 ValueObjectSP return_valobj_sp;
619 Value value;
620
621 ExecutionContext exe_ctx(thread.shared_from_this());
622 if (exe_ctx.GetTargetPtr() == nullptr || exe_ctx.GetProcessPtr() == nullptr)
623 return return_valobj_sp;
624
625 // value.SetContext (Value::eContextTypeClangType, return_compiler_type);
626 value.SetCompilerType(return_compiler_type);
627
628 RegisterContext *reg_ctx = thread.GetRegisterContext().get();
629 if (!reg_ctx)
630 return return_valobj_sp;
631
632 std::optional<uint64_t> byte_size =
633 llvm::expectedToOptional(E: return_compiler_type.GetByteSize(exe_scope: &thread));
634 if (!byte_size)
635 return return_valobj_sp;
636
637 const uint32_t type_flags = return_compiler_type.GetTypeInfo(pointee_or_element_compiler_type: nullptr);
638 if (type_flags & eTypeIsScalar || type_flags & eTypeIsPointer) {
639 value.SetValueType(Value::ValueType::Scalar);
640
641 bool success = false;
642 if (type_flags & eTypeIsInteger || type_flags & eTypeIsPointer) {
643 // Extract the register context so we can read arguments from registers
644 if (*byte_size <= 8) {
645 const RegisterInfo *x0_reg_info = nullptr;
646 x0_reg_info = reg_ctx->GetRegisterInfo(reg_kind: eRegisterKindGeneric,
647 LLDB_REGNUM_GENERIC_ARG1);
648 if (x0_reg_info) {
649 uint64_t raw_value =
650 thread.GetRegisterContext()->ReadRegisterAsUnsigned(reg_info: x0_reg_info,
651 fail_value: 0);
652 const bool is_signed = (type_flags & eTypeIsSigned) != 0;
653 switch (*byte_size) {
654 default:
655 break;
656 case 16: // uint128_t
657 // In register x0 and x1
658 {
659 const RegisterInfo *x1_reg_info = nullptr;
660 x1_reg_info = reg_ctx->GetRegisterInfo(reg_kind: eRegisterKindGeneric,
661 LLDB_REGNUM_GENERIC_ARG2);
662
663 if (x1_reg_info) {
664 if (*byte_size <=
665 x0_reg_info->byte_size + x1_reg_info->byte_size) {
666 std::unique_ptr<DataBufferHeap> heap_data_up(
667 new DataBufferHeap(*byte_size, 0));
668 const ByteOrder byte_order =
669 exe_ctx.GetProcessRef().GetByteOrder();
670 RegisterValue x0_reg_value;
671 RegisterValue x1_reg_value;
672 if (reg_ctx->ReadRegister(reg_info: x0_reg_info, reg_value&: x0_reg_value) &&
673 reg_ctx->ReadRegister(reg_info: x1_reg_info, reg_value&: x1_reg_value)) {
674 Status error;
675 if (x0_reg_value.GetAsMemoryData(
676 reg_info: *x0_reg_info, dst: heap_data_up->GetBytes() + 0, dst_len: 8,
677 dst_byte_order: byte_order, error) &&
678 x1_reg_value.GetAsMemoryData(
679 reg_info: *x1_reg_info, dst: heap_data_up->GetBytes() + 8, dst_len: 8,
680 dst_byte_order: byte_order, error)) {
681 DataExtractor data(
682 DataBufferSP(heap_data_up.release()), byte_order,
683 exe_ctx.GetProcessRef().GetAddressByteSize());
684
685 return_valobj_sp = ValueObjectConstResult::Create(
686 exe_scope: &thread, compiler_type: return_compiler_type, name: ConstString(""), data);
687 return return_valobj_sp;
688 }
689 }
690 }
691 }
692 }
693 break;
694 case sizeof(uint64_t):
695 if (is_signed)
696 value.GetScalar() = (int64_t)(raw_value);
697 else
698 value.GetScalar() = (uint64_t)(raw_value);
699 success = true;
700 break;
701
702 case sizeof(uint32_t):
703 if (is_signed)
704 value.GetScalar() = (int32_t)(raw_value & UINT32_MAX);
705 else
706 value.GetScalar() = (uint32_t)(raw_value & UINT32_MAX);
707 success = true;
708 break;
709
710 case sizeof(uint16_t):
711 if (is_signed)
712 value.GetScalar() = (int16_t)(raw_value & UINT16_MAX);
713 else
714 value.GetScalar() = (uint16_t)(raw_value & UINT16_MAX);
715 success = true;
716 break;
717
718 case sizeof(uint8_t):
719 if (is_signed)
720 value.GetScalar() = (int8_t)(raw_value & UINT8_MAX);
721 else
722 value.GetScalar() = (uint8_t)(raw_value & UINT8_MAX);
723 success = true;
724 break;
725 }
726 }
727 }
728 } else if (type_flags & eTypeIsFloat) {
729 if (type_flags & eTypeIsComplex) {
730 // Don't handle complex yet.
731 } else {
732 if (*byte_size <= sizeof(long double)) {
733 const RegisterInfo *v0_reg_info =
734 reg_ctx->GetRegisterInfoByName(reg_name: "v0", start_idx: 0);
735 RegisterValue v0_value;
736 if (reg_ctx->ReadRegister(reg_info: v0_reg_info, reg_value&: v0_value)) {
737 DataExtractor data;
738 if (v0_value.GetData(data)) {
739 lldb::offset_t offset = 0;
740 if (*byte_size == sizeof(float)) {
741 value.GetScalar() = data.GetFloat(offset_ptr: &offset);
742 success = true;
743 } else if (*byte_size == sizeof(double)) {
744 value.GetScalar() = data.GetDouble(offset_ptr: &offset);
745 success = true;
746 } else if (*byte_size == sizeof(long double)) {
747 value.GetScalar() = data.GetLongDouble(offset_ptr: &offset);
748 success = true;
749 }
750 }
751 }
752 }
753 }
754 }
755
756 if (success)
757 return_valobj_sp = ValueObjectConstResult::Create(
758 exe_scope: thread.GetStackFrameAtIndex(idx: 0).get(), value, name: ConstString(""));
759 } else if (type_flags & eTypeIsVector && *byte_size <= 16) {
760 if (*byte_size > 0) {
761 const RegisterInfo *v0_info = reg_ctx->GetRegisterInfoByName(reg_name: "v0", start_idx: 0);
762
763 if (v0_info) {
764 std::unique_ptr<DataBufferHeap> heap_data_up(
765 new DataBufferHeap(*byte_size, 0));
766 const ByteOrder byte_order = exe_ctx.GetProcessRef().GetByteOrder();
767 RegisterValue reg_value;
768 if (reg_ctx->ReadRegister(reg_info: v0_info, reg_value)) {
769 Status error;
770 if (reg_value.GetAsMemoryData(reg_info: *v0_info, dst: heap_data_up->GetBytes(),
771 dst_len: heap_data_up->GetByteSize(), dst_byte_order: byte_order,
772 error)) {
773 DataExtractor data(DataBufferSP(heap_data_up.release()), byte_order,
774 exe_ctx.GetProcessRef().GetAddressByteSize());
775 return_valobj_sp = ValueObjectConstResult::Create(
776 exe_scope: &thread, compiler_type: return_compiler_type, name: ConstString(""), data);
777 }
778 }
779 }
780 }
781 } else if (type_flags & eTypeIsStructUnion || type_flags & eTypeIsClass ||
782 (type_flags & eTypeIsVector && *byte_size > 16)) {
783 DataExtractor data;
784
785 uint32_t NGRN = 0; // Search ABI docs for NGRN
786 uint32_t NSRN = 0; // Search ABI docs for NSRN
787 const bool is_return_value = true;
788 if (LoadValueFromConsecutiveGPRRegisters(
789 exe_ctx, reg_ctx, value_type: return_compiler_type, is_return_value, NGRN, NSRN,
790 data)) {
791 return_valobj_sp = ValueObjectConstResult::Create(
792 exe_scope: &thread, compiler_type: return_compiler_type, name: ConstString(""), data);
793 }
794 }
795 return return_valobj_sp;
796}
797
798lldb::addr_t ABISysV_arm64::FixAddress(addr_t pc, addr_t mask) {
799 if (mask == LLDB_INVALID_ADDRESS_MASK)
800 return pc;
801 lldb::addr_t pac_sign_extension = 0x0080000000000000ULL;
802 return (pc & pac_sign_extension) ? pc | mask : pc & (~mask);
803}
804
805// Reads code or data address mask for the current Linux process.
806static lldb::addr_t ReadLinuxProcessAddressMask(lldb::ProcessSP process_sp,
807 llvm::StringRef reg_name) {
808 // LLDB_INVALID_ADDRESS_MASK means there isn't a mask or it has not been read
809 // yet. We do not return the top byte mask unless thread_sp is valid. This
810 // prevents calls to this function before the thread is setup locking in the
811 // value to just the top byte mask, in cases where pointer authentication
812 // might also be active.
813 uint64_t address_mask = LLDB_INVALID_ADDRESS_MASK;
814 lldb::ThreadSP thread_sp = process_sp->GetThreadList().GetSelectedThread();
815 if (thread_sp) {
816 // Linux configures user-space virtual addresses with top byte ignored.
817 // We set default value of mask such that top byte is masked out.
818 address_mask = ~((1ULL << 56) - 1);
819 // If Pointer Authentication feature is enabled then Linux exposes
820 // PAC data and code mask register. Try reading relevant register
821 // below and merge it with default address mask calculated above.
822 lldb::RegisterContextSP reg_ctx_sp = thread_sp->GetRegisterContext();
823 if (reg_ctx_sp) {
824 const RegisterInfo *reg_info =
825 reg_ctx_sp->GetRegisterInfoByName(reg_name, start_idx: 0);
826 if (reg_info) {
827 lldb::addr_t mask_reg_val = reg_ctx_sp->ReadRegisterAsUnsigned(
828 reg: reg_info->kinds[eRegisterKindLLDB], LLDB_INVALID_ADDRESS);
829 if (mask_reg_val != LLDB_INVALID_ADDRESS)
830 address_mask |= mask_reg_val;
831 }
832 }
833 }
834 return address_mask;
835}
836
837lldb::addr_t ABISysV_arm64::FixCodeAddress(lldb::addr_t pc) {
838 if (lldb::ProcessSP process_sp = GetProcessSP()) {
839 if (process_sp->GetTarget().GetArchitecture().GetTriple().isOSLinux() &&
840 process_sp->GetCodeAddressMask() == LLDB_INVALID_ADDRESS_MASK)
841 process_sp->SetCodeAddressMask(
842 ReadLinuxProcessAddressMask(process_sp, reg_name: "code_mask"));
843
844 // b55 is the highest bit outside TBI (if it's enabled), use
845 // it to determine if the high bits are set to 0 or 1.
846 const addr_t pac_sign_extension = 0x0080000000000000ULL;
847 addr_t mask = process_sp->GetCodeAddressMask();
848 // Test if the high memory mask has been overriden separately
849 if (pc & pac_sign_extension &&
850 process_sp->GetHighmemCodeAddressMask() != LLDB_INVALID_ADDRESS_MASK)
851 mask = process_sp->GetHighmemCodeAddressMask();
852
853 return FixAddress(pc, mask);
854 }
855 return pc;
856}
857
858lldb::addr_t ABISysV_arm64::FixDataAddress(lldb::addr_t pc) {
859 if (lldb::ProcessSP process_sp = GetProcessSP()) {
860 if (process_sp->GetTarget().GetArchitecture().GetTriple().isOSLinux() &&
861 process_sp->GetDataAddressMask() == LLDB_INVALID_ADDRESS_MASK)
862 process_sp->SetDataAddressMask(
863 ReadLinuxProcessAddressMask(process_sp, reg_name: "data_mask"));
864
865 // b55 is the highest bit outside TBI (if it's enabled), use
866 // it to determine if the high bits are set to 0 or 1.
867 const addr_t pac_sign_extension = 0x0080000000000000ULL;
868 addr_t mask = process_sp->GetDataAddressMask();
869 // Test if the high memory mask has been overriden separately
870 if (pc & pac_sign_extension &&
871 process_sp->GetHighmemDataAddressMask() != LLDB_INVALID_ADDRESS_MASK)
872 mask = process_sp->GetHighmemDataAddressMask();
873
874 return FixAddress(pc, mask);
875 }
876 return pc;
877}
878
879void ABISysV_arm64::Initialize() {
880 PluginManager::RegisterPlugin(name: GetPluginNameStatic(),
881 description: "SysV ABI for AArch64 targets", create_callback: CreateInstance);
882}
883
884void ABISysV_arm64::Terminate() {
885 PluginManager::UnregisterPlugin(create_callback: CreateInstance);
886}
887

source code of lldb/source/Plugins/ABI/AArch64/ABISysV_arm64.cpp