1//===-- ABISysV_riscv.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_riscv.h"
10
11#include <array>
12#include <limits>
13#include <sstream>
14
15#include "llvm/ADT/STLExtras.h"
16#include "llvm/IR/DerivedTypes.h"
17
18#include "Utility/RISCV_DWARF_Registers.h"
19#include "lldb/Core/PluginManager.h"
20#include "lldb/Core/Value.h"
21#include "lldb/Target/RegisterContext.h"
22#include "lldb/Target/StackFrame.h"
23#include "lldb/Target/Thread.h"
24#include "lldb/Utility/LLDBLog.h"
25#include "lldb/Utility/RegisterValue.h"
26#include "lldb/ValueObject/ValueObjectConstResult.h"
27
28#define DEFINE_REG_NAME(reg_num) ConstString(#reg_num).GetCString()
29#define DEFINE_REG_NAME_STR(reg_name) ConstString(reg_name).GetCString()
30
31// The ABI is not a source of such information as size, offset, encoding, etc.
32// of a register. Just provides correct dwarf and eh_frame numbers.
33
34#define DEFINE_GENERIC_REGISTER_STUB(dwarf_num, str_name, generic_num) \
35 { \
36 DEFINE_REG_NAME(dwarf_num), DEFINE_REG_NAME_STR(str_name), 0, 0, \
37 eEncodingInvalid, eFormatDefault, \
38 {dwarf_num, dwarf_num, generic_num, LLDB_INVALID_REGNUM, dwarf_num}, \
39 nullptr, nullptr, nullptr, \
40 }
41
42#define DEFINE_REGISTER_STUB(dwarf_num, str_name) \
43 DEFINE_GENERIC_REGISTER_STUB(dwarf_num, str_name, LLDB_INVALID_REGNUM)
44
45using namespace lldb;
46using namespace lldb_private;
47
48LLDB_PLUGIN_DEFINE_ADV(ABISysV_riscv, ABIRISCV)
49
50namespace {
51namespace dwarf {
52enum regnums {
53 zero,
54 ra,
55 sp,
56 gp,
57 tp,
58 t0,
59 t1,
60 t2,
61 fp,
62 s0 = fp,
63 s1,
64 a0,
65 a1,
66 a2,
67 a3,
68 a4,
69 a5,
70 a6,
71 a7,
72 s2,
73 s3,
74 s4,
75 s5,
76 s6,
77 s7,
78 s8,
79 s9,
80 s10,
81 s11,
82 t3,
83 t4,
84 t5,
85 t6,
86 pc
87};
88
89static const std::array<RegisterInfo, 33> g_register_infos = {
90 ._M_elems: {DEFINE_REGISTER_STUB(zero, nullptr),
91 DEFINE_GENERIC_REGISTER_STUB(ra, nullptr, LLDB_REGNUM_GENERIC_RA),
92 DEFINE_GENERIC_REGISTER_STUB(sp, nullptr, LLDB_REGNUM_GENERIC_SP),
93 DEFINE_REGISTER_STUB(gp, nullptr),
94 DEFINE_REGISTER_STUB(tp, nullptr),
95 DEFINE_REGISTER_STUB(t0, nullptr),
96 DEFINE_REGISTER_STUB(t1, nullptr),
97 DEFINE_REGISTER_STUB(t2, nullptr),
98 DEFINE_GENERIC_REGISTER_STUB(fp, nullptr, LLDB_REGNUM_GENERIC_FP),
99 DEFINE_REGISTER_STUB(s1, nullptr),
100 DEFINE_GENERIC_REGISTER_STUB(a0, nullptr, LLDB_REGNUM_GENERIC_ARG1),
101 DEFINE_GENERIC_REGISTER_STUB(a1, nullptr, LLDB_REGNUM_GENERIC_ARG2),
102 DEFINE_GENERIC_REGISTER_STUB(a2, nullptr, LLDB_REGNUM_GENERIC_ARG3),
103 DEFINE_GENERIC_REGISTER_STUB(a3, nullptr, LLDB_REGNUM_GENERIC_ARG4),
104 DEFINE_GENERIC_REGISTER_STUB(a4, nullptr, LLDB_REGNUM_GENERIC_ARG5),
105 DEFINE_GENERIC_REGISTER_STUB(a5, nullptr, LLDB_REGNUM_GENERIC_ARG6),
106 DEFINE_GENERIC_REGISTER_STUB(a6, nullptr, LLDB_REGNUM_GENERIC_ARG7),
107 DEFINE_GENERIC_REGISTER_STUB(a7, nullptr, LLDB_REGNUM_GENERIC_ARG8),
108 DEFINE_REGISTER_STUB(s2, nullptr),
109 DEFINE_REGISTER_STUB(s3, nullptr),
110 DEFINE_REGISTER_STUB(s4, nullptr),
111 DEFINE_REGISTER_STUB(s5, nullptr),
112 DEFINE_REGISTER_STUB(s6, nullptr),
113 DEFINE_REGISTER_STUB(s7, nullptr),
114 DEFINE_REGISTER_STUB(s8, nullptr),
115 DEFINE_REGISTER_STUB(s9, nullptr),
116 DEFINE_REGISTER_STUB(s10, nullptr),
117 DEFINE_REGISTER_STUB(s11, nullptr),
118 DEFINE_REGISTER_STUB(t3, nullptr),
119 DEFINE_REGISTER_STUB(t4, nullptr),
120 DEFINE_REGISTER_STUB(t5, nullptr),
121 DEFINE_REGISTER_STUB(t6, nullptr),
122 DEFINE_GENERIC_REGISTER_STUB(pc, nullptr, LLDB_REGNUM_GENERIC_PC)}};
123} // namespace dwarf
124} // namespace
125
126// Number of argument registers (the base integer calling convention
127// provides 8 argument registers, a0-a7)
128static constexpr size_t g_regs_for_args_count = 8U;
129
130const RegisterInfo *ABISysV_riscv::GetRegisterInfoArray(uint32_t &count) {
131 count = dwarf::g_register_infos.size();
132 return dwarf::g_register_infos.data();
133}
134
135//------------------------------------------------------------------
136// Static Functions
137//------------------------------------------------------------------
138
139ABISP
140ABISysV_riscv::CreateInstance(ProcessSP process_sp, const ArchSpec &arch) {
141 llvm::Triple::ArchType machine = arch.GetTriple().getArch();
142
143 if (llvm::Triple::riscv32 != machine && llvm::Triple::riscv64 != machine)
144 return ABISP();
145
146 ABISysV_riscv *abi = new ABISysV_riscv(std::move(process_sp),
147 MakeMCRegisterInfo(arch));
148 if (abi)
149 abi->SetIsRV64((llvm::Triple::riscv64 == machine) ? true : false);
150 return ABISP(abi);
151}
152
153static inline size_t AugmentArgSize(bool is_rv64, size_t size_in_bytes) {
154 size_t word_size = is_rv64 ? 8 : 4;
155 return llvm::alignTo(Value: size_in_bytes, Align: word_size);
156}
157
158static size_t
159TotalArgsSizeInWords(bool is_rv64,
160 const llvm::ArrayRef<ABI::CallArgument> &args) {
161 size_t reg_size = is_rv64 ? 8 : 4;
162 size_t word_size = reg_size;
163 size_t total_size = 0;
164 for (const auto &arg : args)
165 total_size +=
166 (ABI::CallArgument::TargetValue == arg.type ? AugmentArgSize(is_rv64,
167 size_in_bytes: arg.size)
168 : reg_size) /
169 word_size;
170
171 return total_size;
172}
173
174static bool UpdateRegister(RegisterContext *reg_ctx,
175 const lldb::RegisterKind reg_kind,
176 const uint32_t reg_num, const addr_t value) {
177 Log *log = GetLog(mask: LLDBLog::Expressions);
178
179 const RegisterInfo *reg_info = reg_ctx->GetRegisterInfo(reg_kind, reg_num);
180
181 LLDB_LOG(log, "Writing {0}: 0x{1:x}", reg_info->name,
182 static_cast<uint64_t>(value));
183 if (!reg_ctx->WriteRegisterFromUnsigned(reg_info, uval: value)) {
184 LLDB_LOG(log, "Writing {0}: failed", reg_info->name);
185 return false;
186 }
187 return true;
188}
189
190static void LogInitInfo(Log &log, const Thread &thread, addr_t sp,
191 addr_t func_addr, addr_t return_addr,
192 const llvm::ArrayRef<addr_t> args) {
193 std::stringstream ss;
194 ss << "ABISysV_riscv::PrepareTrivialCall"
195 << " (tid = 0x" << std::hex << thread.GetID() << ", sp = 0x" << sp
196 << ", func_addr = 0x" << func_addr << ", return_addr = 0x" << return_addr;
197
198 for (auto [idx, arg] : enumerate(First: args))
199 ss << ", arg" << std::dec << idx << " = 0x" << std::hex << arg;
200 ss << ")";
201 log.PutString(str: ss.str());
202}
203
204bool ABISysV_riscv::PrepareTrivialCall(Thread &thread, addr_t sp,
205 addr_t func_addr, addr_t return_addr,
206 llvm::ArrayRef<addr_t> args) const {
207 Log *log = GetLog(mask: LLDBLog::Expressions);
208 if (log)
209 LogInitInfo(log&: *log, thread, sp, func_addr, return_addr, args);
210
211 const auto reg_ctx_sp = thread.GetRegisterContext();
212 if (!reg_ctx_sp) {
213 LLDB_LOG(log, "Failed to get RegisterContext");
214 return false;
215 }
216
217 if (args.size() > g_regs_for_args_count) {
218 LLDB_LOG(log, "Function has {0} arguments, but only {1} are allowed!",
219 args.size(), g_regs_for_args_count);
220 return false;
221 }
222
223 // Write arguments to registers
224 for (auto [idx, arg] : enumerate(First&: args)) {
225 const RegisterInfo *reg_info = reg_ctx_sp->GetRegisterInfo(
226 reg_kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG1 + idx);
227 LLDB_LOG(log, "About to write arg{0} (0x{1:x}) into {2}", idx, arg,
228 reg_info->name);
229
230 if (!reg_ctx_sp->WriteRegisterFromUnsigned(reg_info, uval: arg)) {
231 LLDB_LOG(log, "Failed to write arg{0} (0x{1:x}) into {2}", idx, arg,
232 reg_info->name);
233 return false;
234 }
235 }
236
237 if (!UpdateRegister(reg_ctx: reg_ctx_sp.get(), reg_kind: eRegisterKindGeneric,
238 LLDB_REGNUM_GENERIC_PC, value: func_addr))
239 return false;
240 if (!UpdateRegister(reg_ctx: reg_ctx_sp.get(), reg_kind: eRegisterKindGeneric,
241 LLDB_REGNUM_GENERIC_SP, value: sp))
242 return false;
243 if (!UpdateRegister(reg_ctx: reg_ctx_sp.get(), reg_kind: eRegisterKindGeneric,
244 LLDB_REGNUM_GENERIC_RA, value: return_addr))
245 return false;
246
247 LLDB_LOG(log, "ABISysV_riscv::{0}() success", __FUNCTION__);
248 return true;
249}
250
251bool ABISysV_riscv::PrepareTrivialCall(
252 Thread &thread, addr_t sp, addr_t pc, addr_t ra, llvm::Type &prototype,
253 llvm::ArrayRef<ABI::CallArgument> args) const {
254 auto reg_ctx = thread.GetRegisterContext();
255 if (!reg_ctx)
256 return false;
257
258 uint32_t pc_reg = reg_ctx->ConvertRegisterKindToRegisterNumber(
259 kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
260 if (pc_reg == LLDB_INVALID_REGNUM)
261 return false;
262
263 uint32_t ra_reg = reg_ctx->ConvertRegisterKindToRegisterNumber(
264 kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_RA);
265 if (ra_reg == LLDB_INVALID_REGNUM)
266 return false;
267
268 uint32_t sp_reg = reg_ctx->ConvertRegisterKindToRegisterNumber(
269 kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_SP);
270 if (sp_reg == LLDB_INVALID_REGNUM)
271 return false;
272
273 Status error;
274 ProcessSP process = thread.GetProcess();
275 if (!process)
276 return false;
277
278 size_t reg_size = m_is_rv64 ? 8 : 4;
279 size_t word_size = reg_size;
280 // Push host data onto target.
281 for (const auto &arg : args) {
282 // Skip over target values.
283 if (arg.type == ABI::CallArgument::TargetValue)
284 continue;
285
286 // Create space on the host stack for this data 4-byte aligned.
287 sp -= AugmentArgSize(is_rv64: m_is_rv64, size_in_bytes: arg.size);
288
289 if (process->WriteMemory(vm_addr: sp, buf: arg.data_up.get(), size: arg.size, error) <
290 arg.size ||
291 error.Fail())
292 return false;
293
294 // Update the argument with the target pointer.
295 *const_cast<addr_t *>(&arg.value) = sp;
296 }
297
298 // Make sure number of parameters matches prototype.
299 assert(prototype.getFunctionNumParams() == args.size());
300
301 const size_t num_args = args.size();
302 const size_t num_args_in_regs =
303 num_args > g_regs_for_args_count ? g_regs_for_args_count : num_args;
304
305 // Number of arguments passed on stack.
306 size_t args_size = TotalArgsSizeInWords(is_rv64: m_is_rv64, args);
307 auto on_stack = args_size <= g_regs_for_args_count
308 ? 0
309 : args_size - g_regs_for_args_count;
310 auto offset = on_stack * word_size;
311
312 uint8_t reg_value[8];
313 size_t reg_index = LLDB_REGNUM_GENERIC_ARG1;
314
315 for (size_t i = 0; i < args_size; ++i) {
316 auto value = reinterpret_cast<const uint8_t *>(&args[i].value);
317 auto size =
318 ABI::CallArgument::TargetValue == args[i].type ? args[i].size : reg_size;
319
320 // Pass arguments via registers.
321 if (i < num_args_in_regs) {
322 // copy value to register, padding if arg is smaller than register
323 auto end = size < reg_size ? size : reg_size;
324 memcpy(dest: reg_value, src: value, n: end);
325 if (reg_size > end)
326 memset(s: reg_value + end, c: 0, n: reg_size - end);
327
328 RegisterValue reg_val_obj(llvm::ArrayRef(reg_value, reg_size),
329 eByteOrderLittle);
330 if (!reg_ctx->WriteRegister(
331 reg_info: reg_ctx->GetRegisterInfo(reg_kind: eRegisterKindGeneric, reg_num: reg_index),
332 reg_value: reg_val_obj))
333 return false;
334
335 // NOTE: It's unsafe to iterate through LLDB_REGNUM_GENERICs
336 // But the "a" registers are sequential in the RISC-V register space
337 ++reg_index;
338 }
339
340 if (reg_index < g_regs_for_args_count || size == 0)
341 continue;
342
343 // Remaining arguments are passed on the stack.
344 if (process->WriteMemory(vm_addr: sp - offset, buf: value, size, error) < size ||
345 !error.Success())
346 return false;
347
348 offset -= AugmentArgSize(is_rv64: m_is_rv64, size_in_bytes: size);
349 }
350
351 // Set stack pointer immediately below arguments.
352 sp -= on_stack * word_size;
353
354 // Update registers with current function call state.
355 reg_ctx->WriteRegisterFromUnsigned(reg: pc_reg, uval: pc);
356 reg_ctx->WriteRegisterFromUnsigned(reg: ra_reg, uval: ra);
357 reg_ctx->WriteRegisterFromUnsigned(reg: sp_reg, uval: sp);
358
359 return true;
360}
361
362bool ABISysV_riscv::GetArgumentValues(Thread &thread, ValueList &values) const {
363 // TODO: Implement
364 return false;
365}
366
367Status ABISysV_riscv::SetReturnValueObject(StackFrameSP &frame_sp,
368 ValueObjectSP &new_value_sp) {
369 Status result;
370 if (!new_value_sp) {
371 result = Status::FromErrorString(str: "Empty value object for return value.");
372 return result;
373 }
374
375 CompilerType compiler_type = new_value_sp->GetCompilerType();
376 if (!compiler_type) {
377 result = Status::FromErrorString(str: "Null clang type for return value.");
378 return result;
379 }
380
381 auto &reg_ctx = *frame_sp->GetThread()->GetRegisterContext();
382
383 bool is_signed = false;
384 if (!compiler_type.IsIntegerOrEnumerationType(is_signed) &&
385 !compiler_type.IsPointerType()) {
386 result = Status::FromErrorString(
387 str: "We don't support returning other types at present");
388 return result;
389 }
390
391 DataExtractor data;
392 size_t num_bytes = new_value_sp->GetData(data, error&: result);
393
394 if (result.Fail()) {
395 result = Status::FromErrorStringWithFormat(
396 format: "Couldn't convert return value to raw data: %s", result.AsCString());
397 return result;
398 }
399
400 size_t reg_size = m_is_rv64 ? 8 : 4;
401 if (num_bytes <= 2 * reg_size) {
402 offset_t offset = 0;
403 uint64_t raw_value = data.GetMaxU64(offset_ptr: &offset, byte_size: num_bytes);
404
405 auto reg_info =
406 reg_ctx.GetRegisterInfo(reg_kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG1);
407 if (!reg_ctx.WriteRegisterFromUnsigned(reg_info, uval: raw_value)) {
408 result = Status::FromErrorStringWithFormat(
409 format: "Couldn't write value to register %s", reg_info->name);
410 return result;
411 }
412
413 if (num_bytes <= reg_size)
414 return result; // Successfully written.
415
416 // for riscv32, get the upper 32 bits from raw_value and write them
417 // for riscv64, get the next 64 bits from data and write them
418 if (4 == reg_size)
419 raw_value >>= 32;
420 else
421 raw_value = data.GetMaxU64(offset_ptr: &offset, byte_size: num_bytes - reg_size);
422 reg_info =
423 reg_ctx.GetRegisterInfo(reg_kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG2);
424 if (!reg_ctx.WriteRegisterFromUnsigned(reg_info, uval: raw_value)) {
425 result = Status::FromErrorStringWithFormat(
426 format: "Couldn't write value to register %s", reg_info->name);
427 }
428
429 return result;
430 }
431
432 result = Status::FromErrorString(
433 str: "We don't support returning large integer values at present.");
434 return result;
435}
436
437template <typename T>
438static void SetInteger(Scalar &scalar, uint64_t raw_value, bool is_signed) {
439 raw_value &= std::numeric_limits<T>::max();
440 if (is_signed)
441 scalar = static_cast<typename std::make_signed<T>::type>(raw_value);
442 else
443 scalar = static_cast<T>(raw_value);
444}
445
446static bool SetSizedInteger(Scalar &scalar, uint64_t raw_value,
447 uint8_t size_in_bytes, bool is_signed) {
448 switch (size_in_bytes) {
449 default:
450 return false;
451
452 case sizeof(uint64_t):
453 SetInteger<uint64_t>(scalar, raw_value, is_signed);
454 break;
455
456 case sizeof(uint32_t):
457 SetInteger<uint32_t>(scalar, raw_value, is_signed);
458 break;
459
460 case sizeof(uint16_t):
461 SetInteger<uint16_t>(scalar, raw_value, is_signed);
462 break;
463
464 case sizeof(uint8_t):
465 SetInteger<uint8_t>(scalar, raw_value, is_signed);
466 break;
467 }
468
469 return true;
470}
471
472static bool SetSizedFloat(Scalar &scalar, uint64_t raw_value,
473 uint8_t size_in_bytes) {
474 switch (size_in_bytes) {
475 default:
476 return false;
477
478 case sizeof(uint64_t):
479 scalar = *reinterpret_cast<double *>(&raw_value);
480 break;
481
482 case sizeof(uint32_t):
483 scalar = *reinterpret_cast<float *>(&raw_value);
484 break;
485 }
486
487 return true;
488}
489
490static ValueObjectSP GetValObjFromIntRegs(Thread &thread,
491 const RegisterContextSP &reg_ctx,
492 llvm::Triple::ArchType machine,
493 uint32_t type_flags,
494 uint32_t byte_size) {
495 Value value;
496 ValueObjectSP return_valobj_sp;
497 auto reg_info_a0 =
498 reg_ctx->GetRegisterInfo(reg_kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG1);
499 auto reg_info_a1 =
500 reg_ctx->GetRegisterInfo(reg_kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG2);
501 uint64_t raw_value;
502
503 switch (byte_size) {
504 case sizeof(uint32_t):
505 // Read a0 to get the arg
506 raw_value = reg_ctx->ReadRegisterAsUnsigned(reg_info: reg_info_a0, fail_value: 0) & UINT32_MAX;
507 break;
508 case sizeof(uint64_t):
509 // Read a0 to get the arg on riscv64, a0 and a1 on riscv32
510 if (llvm::Triple::riscv32 == machine) {
511 raw_value = reg_ctx->ReadRegisterAsUnsigned(reg_info: reg_info_a0, fail_value: 0) & UINT32_MAX;
512 raw_value |=
513 (reg_ctx->ReadRegisterAsUnsigned(reg_info: reg_info_a1, fail_value: 0) & UINT32_MAX) << 32U;
514 } else {
515 raw_value = reg_ctx->ReadRegisterAsUnsigned(reg_info: reg_info_a0, fail_value: 0);
516 }
517 break;
518 case 16: {
519 // Read a0 and a1 to get the arg on riscv64, not supported on riscv32
520 if (llvm::Triple::riscv32 == machine)
521 return return_valobj_sp;
522
523 // Create the ValueObjectSP here and return
524 std::unique_ptr<DataBufferHeap> heap_data_up(
525 new DataBufferHeap(byte_size, 0));
526 const ByteOrder byte_order = thread.GetProcess()->GetByteOrder();
527 RegisterValue reg_value_a0, reg_value_a1;
528 if (reg_ctx->ReadRegister(reg_info: reg_info_a0, reg_value&: reg_value_a0) &&
529 reg_ctx->ReadRegister(reg_info: reg_info_a1, reg_value&: reg_value_a1)) {
530 Status error;
531 if (reg_value_a0.GetAsMemoryData(reg_info: *reg_info_a0,
532 dst: heap_data_up->GetBytes() + 0, dst_len: 8,
533 dst_byte_order: byte_order, error) &&
534 reg_value_a1.GetAsMemoryData(reg_info: *reg_info_a1,
535 dst: heap_data_up->GetBytes() + 8, dst_len: 8,
536 dst_byte_order: byte_order, error)) {
537 value.SetBytes(bytes: heap_data_up.release(), len: byte_size);
538 return ValueObjectConstResult::Create(
539 exe_scope: thread.GetStackFrameAtIndex(idx: 0).get(), value, name: ConstString(""));
540 }
541 }
542 break;
543 }
544 default:
545 return return_valobj_sp;
546 }
547
548 if (type_flags & eTypeIsInteger) {
549 const bool is_signed = (type_flags & eTypeIsSigned) != 0;
550 if (!SetSizedInteger(scalar&: value.GetScalar(), raw_value, size_in_bytes: byte_size, is_signed))
551 return return_valobj_sp;
552 } else if (type_flags & eTypeIsFloat) {
553 if (!SetSizedFloat(scalar&: value.GetScalar(), raw_value, size_in_bytes: byte_size))
554 return return_valobj_sp;
555 } else
556 return return_valobj_sp;
557
558 value.SetValueType(Value::ValueType::Scalar);
559 return_valobj_sp = ValueObjectConstResult::Create(
560 exe_scope: thread.GetStackFrameAtIndex(idx: 0).get(), value, name: ConstString(""));
561 return return_valobj_sp;
562}
563
564static ValueObjectSP
565GetValObjFromFPRegs(Thread &thread, const RegisterContextSP &reg_ctx,
566 llvm::Triple::ArchType machine, uint32_t arch_fp_flags,
567 uint32_t type_flags, uint32_t byte_size) {
568 auto reg_info_fa0 = reg_ctx->GetRegisterInfoByName(reg_name: "fa0");
569 bool use_fp_regs = false;
570 ValueObjectSP return_valobj_sp;
571
572 switch (arch_fp_flags) {
573 // fp return value in integer registers a0 and possibly a1
574 case ArchSpec::eRISCV_float_abi_soft:
575 return_valobj_sp =
576 GetValObjFromIntRegs(thread, reg_ctx, machine, type_flags, byte_size);
577 return return_valobj_sp;
578 // fp return value in fp register fa0 (only float)
579 case ArchSpec::eRISCV_float_abi_single:
580 if (byte_size <= 4)
581 use_fp_regs = true;
582 break;
583 // fp return value in fp registers fa0 (float, double)
584 case ArchSpec::eRISCV_float_abi_double:
585 [[fallthrough]];
586 // fp return value in fp registers fa0 (float, double, quad)
587 // not implemented; act like they're doubles
588 case ArchSpec::eRISCV_float_abi_quad:
589 if (byte_size <= 8)
590 use_fp_regs = true;
591 break;
592 }
593
594 if (use_fp_regs) {
595 uint64_t raw_value;
596 Value value;
597 raw_value = reg_ctx->ReadRegisterAsUnsigned(reg_info: reg_info_fa0, fail_value: 0);
598 if (!SetSizedFloat(scalar&: value.GetScalar(), raw_value, size_in_bytes: byte_size))
599 return return_valobj_sp;
600 value.SetValueType(Value::ValueType::Scalar);
601 return ValueObjectConstResult::Create(exe_scope: thread.GetStackFrameAtIndex(idx: 0).get(),
602 value, name: ConstString(""));
603 }
604 // we should never reach this, but if we do, use the integer registers
605 return GetValObjFromIntRegs(thread, reg_ctx, machine, type_flags, byte_size);
606}
607
608ValueObjectSP
609ABISysV_riscv::GetReturnValueObjectSimple(Thread &thread,
610 CompilerType &compiler_type) const {
611 ValueObjectSP return_valobj_sp;
612
613 if (!compiler_type)
614 return return_valobj_sp;
615
616 auto reg_ctx = thread.GetRegisterContext();
617 if (!reg_ctx)
618 return return_valobj_sp;
619
620 Value value;
621 value.SetCompilerType(compiler_type);
622
623 const uint32_t type_flags = compiler_type.GetTypeInfo();
624 const size_t byte_size =
625 llvm::expectedToOptional(E: compiler_type.GetByteSize(exe_scope: &thread)).value_or(u: 0);
626 const ArchSpec arch = thread.GetProcess()->GetTarget().GetArchitecture();
627 const llvm::Triple::ArchType machine = arch.GetMachine();
628
629 // Integer return type.
630 if (type_flags & eTypeIsInteger) {
631 return_valobj_sp =
632 GetValObjFromIntRegs(thread, reg_ctx, machine, type_flags, byte_size);
633 return return_valobj_sp;
634 }
635 // Pointer return type.
636 else if (type_flags & eTypeIsPointer) {
637 auto reg_info_a0 = reg_ctx->GetRegisterInfo(reg_kind: eRegisterKindGeneric,
638 LLDB_REGNUM_GENERIC_ARG1);
639 value.GetScalar() = reg_ctx->ReadRegisterAsUnsigned(reg_info: reg_info_a0, fail_value: 0);
640 value.SetValueType(Value::ValueType::Scalar);
641 return ValueObjectConstResult::Create(exe_scope: thread.GetStackFrameAtIndex(idx: 0).get(),
642 value, name: ConstString(""));
643 }
644 // Floating point return type.
645 else if (type_flags & eTypeIsFloat) {
646 uint32_t float_count = 0;
647 bool is_complex = false;
648
649 if (compiler_type.IsFloatingPointType(count&: float_count, is_complex) &&
650 float_count == 1 && !is_complex) {
651 const uint32_t arch_fp_flags =
652 arch.GetFlags() & ArchSpec::eRISCV_float_abi_mask;
653 return_valobj_sp = GetValObjFromFPRegs(
654 thread, reg_ctx, machine, arch_fp_flags, type_flags, byte_size);
655 return return_valobj_sp;
656 }
657 }
658 // Unsupported return type.
659 return return_valobj_sp;
660}
661
662ValueObjectSP
663ABISysV_riscv::GetReturnValueObjectImpl(lldb_private::Thread &thread,
664 llvm::Type &type) const {
665 Value value;
666 ValueObjectSP return_valobj_sp;
667
668 auto reg_ctx = thread.GetRegisterContext();
669 if (!reg_ctx)
670 return return_valobj_sp;
671
672 uint32_t type_flags = 0;
673 if (type.isIntegerTy())
674 type_flags = eTypeIsInteger;
675 else if (type.isVoidTy())
676 type_flags = eTypeIsPointer;
677 else if (type.isFloatTy())
678 type_flags = eTypeIsFloat;
679
680 const uint32_t byte_size = type.getPrimitiveSizeInBits() / CHAR_BIT;
681 const ArchSpec arch = thread.GetProcess()->GetTarget().GetArchitecture();
682 const llvm::Triple::ArchType machine = arch.GetMachine();
683
684 // Integer return type.
685 if (type_flags & eTypeIsInteger) {
686 return_valobj_sp =
687 GetValObjFromIntRegs(thread, reg_ctx, machine, type_flags, byte_size);
688 return return_valobj_sp;
689 }
690 // Pointer return type.
691 else if (type_flags & eTypeIsPointer) {
692 auto reg_info_a0 = reg_ctx->GetRegisterInfo(reg_kind: eRegisterKindGeneric,
693 LLDB_REGNUM_GENERIC_ARG1);
694 value.GetScalar() = reg_ctx->ReadRegisterAsUnsigned(reg_info: reg_info_a0, fail_value: 0);
695 value.SetValueType(Value::ValueType::Scalar);
696 return ValueObjectConstResult::Create(exe_scope: thread.GetStackFrameAtIndex(idx: 0).get(),
697 value, name: ConstString(""));
698 }
699 // Floating point return type.
700 else if (type_flags & eTypeIsFloat) {
701 const uint32_t arch_fp_flags =
702 arch.GetFlags() & ArchSpec::eRISCV_float_abi_mask;
703 return_valobj_sp = GetValObjFromFPRegs(
704 thread, reg_ctx, machine, arch_fp_flags, type_flags, byte_size);
705 return return_valobj_sp;
706 }
707 // Unsupported return type.
708 return return_valobj_sp;
709}
710
711ValueObjectSP ABISysV_riscv::GetReturnValueObjectImpl(
712 Thread &thread, CompilerType &return_compiler_type) const {
713 ValueObjectSP return_valobj_sp;
714
715 if (!return_compiler_type)
716 return return_valobj_sp;
717
718 ExecutionContext exe_ctx(thread.shared_from_this());
719 return GetReturnValueObjectSimple(thread, compiler_type&: return_compiler_type);
720}
721
722UnwindPlanSP ABISysV_riscv::CreateFunctionEntryUnwindPlan() {
723 uint32_t pc_reg_num = riscv_dwarf::dwarf_gpr_pc;
724 uint32_t sp_reg_num = riscv_dwarf::dwarf_gpr_sp;
725 uint32_t ra_reg_num = riscv_dwarf::dwarf_gpr_ra;
726
727 UnwindPlan::Row row;
728
729 // Define CFA as the stack pointer
730 row.GetCFAValue().SetIsRegisterPlusOffset(reg_num: sp_reg_num, offset: 0);
731
732 // Previous frame's pc is in ra
733 row.SetRegisterLocationToRegister(reg_num: pc_reg_num, other_reg_num: ra_reg_num, can_replace: true);
734
735 auto plan_sp = std::make_shared<UnwindPlan>(args: eRegisterKindDWARF);
736 plan_sp->AppendRow(row: std::move(row));
737 plan_sp->SetSourceName("riscv function-entry unwind plan");
738 plan_sp->SetSourcedFromCompiler(eLazyBoolNo);
739 return plan_sp;
740}
741
742UnwindPlanSP ABISysV_riscv::CreateDefaultUnwindPlan() {
743 uint32_t pc_reg_num = LLDB_REGNUM_GENERIC_PC;
744 uint32_t fp_reg_num = LLDB_REGNUM_GENERIC_FP;
745
746 UnwindPlan::Row row;
747
748 // Define the CFA as the current frame pointer value.
749 row.GetCFAValue().SetIsRegisterPlusOffset(reg_num: fp_reg_num, offset: 0);
750
751 int reg_size = 4;
752 if (m_is_rv64)
753 reg_size = 8;
754
755 // Assume the ra reg (return pc) and caller's frame pointer
756 // have been spilled to stack already.
757 row.SetRegisterLocationToAtCFAPlusOffset(reg_num: fp_reg_num, offset: reg_size * -2, can_replace: true);
758 row.SetRegisterLocationToAtCFAPlusOffset(reg_num: pc_reg_num, offset: reg_size * -1, can_replace: true);
759
760 auto plan_sp = std::make_shared<UnwindPlan>(args: eRegisterKindGeneric);
761 plan_sp->AppendRow(row: std::move(row));
762 plan_sp->SetSourceName("riscv default unwind plan");
763 plan_sp->SetSourcedFromCompiler(eLazyBoolNo);
764 plan_sp->SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
765 return plan_sp;
766}
767
768bool ABISysV_riscv::RegisterIsVolatile(const RegisterInfo *reg_info) {
769 return !RegisterIsCalleeSaved(reg_info);
770}
771
772bool ABISysV_riscv::RegisterIsCalleeSaved(const RegisterInfo *reg_info) {
773 if (!reg_info)
774 return false;
775
776 const char *name = reg_info->name;
777 ArchSpec arch = GetProcessSP()->GetTarget().GetArchitecture();
778 uint32_t arch_flags = arch.GetFlags();
779 // floating point registers are only callee saved when using
780 // F, D or Q hardware floating point ABIs
781 bool is_hw_fp = (arch_flags & ArchSpec::eRISCV_float_abi_mask) != 0;
782
783 bool is_callee_saved =
784 llvm::StringSwitch<bool>(name)
785 // integer ABI names
786 .Cases(S0: "ra", S1: "sp", S2: "fp", Value: true)
787 .Cases(S0: "s0", S1: "s1", S2: "s2", S3: "s3", S4: "s4", S5: "s5", S6: "s6", S7: "s7", S8: "s8", S9: "s9",
788 Value: true)
789 .Cases(S0: "s10", S1: "s11", Value: true)
790 // integer hardware names
791 .Cases(S0: "x1", S1: "x2", S2: "x8", S3: "x9", S4: "x18", S5: "x19", S6: "x20", S7: "x21", S8: "x22",
792 Value: true)
793 .Cases(S0: "x23", S1: "x24", S2: "x25", S3: "x26", S4: "x27", Value: true)
794 // floating point ABI names
795 .Cases(S0: "fs0", S1: "fs1", S2: "fs2", S3: "fs3", S4: "fs4", S5: "fs5", S6: "fs6", S7: "fs7",
796 Value: is_hw_fp)
797 .Cases(S0: "fs8", S1: "fs9", S2: "fs10", S3: "fs11", Value: is_hw_fp)
798 // floating point hardware names
799 .Cases(S0: "f8", S1: "f9", S2: "f18", S3: "f19", S4: "f20", S5: "f21", S6: "f22", S7: "f23", Value: is_hw_fp)
800 .Cases(S0: "f24", S1: "f25", S2: "f26", S3: "f27", Value: is_hw_fp)
801 .Default(Value: false);
802
803 return is_callee_saved;
804}
805
806void ABISysV_riscv::Initialize() {
807 PluginManager::RegisterPlugin(
808 name: GetPluginNameStatic(), description: "System V ABI for RISCV targets", create_callback: CreateInstance);
809}
810
811void ABISysV_riscv::Terminate() {
812 PluginManager::UnregisterPlugin(create_callback: CreateInstance);
813}
814
815static uint32_t GetGenericNum(llvm::StringRef name) {
816 return llvm::StringSwitch<uint32_t>(name)
817 .Case(S: "pc", LLDB_REGNUM_GENERIC_PC)
818 .Cases(S0: "ra", S1: "x1", LLDB_REGNUM_GENERIC_RA)
819 .Cases(S0: "sp", S1: "x2", LLDB_REGNUM_GENERIC_SP)
820 .Cases(S0: "fp", S1: "s0", LLDB_REGNUM_GENERIC_FP)
821 .Case(S: "a0", LLDB_REGNUM_GENERIC_ARG1)
822 .Case(S: "a1", LLDB_REGNUM_GENERIC_ARG2)
823 .Case(S: "a2", LLDB_REGNUM_GENERIC_ARG3)
824 .Case(S: "a3", LLDB_REGNUM_GENERIC_ARG4)
825 .Case(S: "a4", LLDB_REGNUM_GENERIC_ARG5)
826 .Case(S: "a5", LLDB_REGNUM_GENERIC_ARG6)
827 .Case(S: "a6", LLDB_REGNUM_GENERIC_ARG7)
828 .Case(S: "a7", LLDB_REGNUM_GENERIC_ARG8)
829 .Default(LLDB_INVALID_REGNUM);
830}
831
832void ABISysV_riscv::AugmentRegisterInfo(
833 std::vector<lldb_private::DynamicRegisterInfo::Register> &regs) {
834 lldb_private::RegInfoBasedABI::AugmentRegisterInfo(regs);
835
836 for (auto it : llvm::enumerate(First&: regs)) {
837 // Set alt name for certain registers for convenience
838 if (it.value().name == "zero")
839 it.value().alt_name.SetCString("x0");
840 else if (it.value().name == "ra")
841 it.value().alt_name.SetCString("x1");
842 else if (it.value().name == "sp")
843 it.value().alt_name.SetCString("x2");
844 else if (it.value().name == "gp")
845 it.value().alt_name.SetCString("x3");
846 else if (it.value().name == "fp")
847 it.value().alt_name.SetCString("s0");
848 else if (it.value().name == "tp")
849 it.value().alt_name.SetCString("x4");
850 else if (it.value().name == "s0")
851 it.value().alt_name.SetCString("x8");
852 else if (it.value().name == "s1")
853 it.value().alt_name.SetCString("x9");
854 else if (it.value().name == "t0")
855 it.value().alt_name.SetCString("x5");
856 else if (it.value().name == "t1")
857 it.value().alt_name.SetCString("x6");
858 else if (it.value().name == "t2")
859 it.value().alt_name.SetCString("x7");
860 else if (it.value().name == "a0")
861 it.value().alt_name.SetCString("x10");
862 else if (it.value().name == "a1")
863 it.value().alt_name.SetCString("x11");
864 else if (it.value().name == "a2")
865 it.value().alt_name.SetCString("x12");
866 else if (it.value().name == "a3")
867 it.value().alt_name.SetCString("x13");
868 else if (it.value().name == "a4")
869 it.value().alt_name.SetCString("x14");
870 else if (it.value().name == "a5")
871 it.value().alt_name.SetCString("x15");
872 else if (it.value().name == "a6")
873 it.value().alt_name.SetCString("x16");
874 else if (it.value().name == "a7")
875 it.value().alt_name.SetCString("x17");
876 else if (it.value().name == "s2")
877 it.value().alt_name.SetCString("x18");
878 else if (it.value().name == "s3")
879 it.value().alt_name.SetCString("x19");
880 else if (it.value().name == "s4")
881 it.value().alt_name.SetCString("x20");
882 else if (it.value().name == "s5")
883 it.value().alt_name.SetCString("x21");
884 else if (it.value().name == "s6")
885 it.value().alt_name.SetCString("x22");
886 else if (it.value().name == "s7")
887 it.value().alt_name.SetCString("x23");
888 else if (it.value().name == "s8")
889 it.value().alt_name.SetCString("x24");
890 else if (it.value().name == "s9")
891 it.value().alt_name.SetCString("x25");
892 else if (it.value().name == "s10")
893 it.value().alt_name.SetCString("x26");
894 else if (it.value().name == "s11")
895 it.value().alt_name.SetCString("x27");
896 else if (it.value().name == "t3")
897 it.value().alt_name.SetCString("x28");
898 else if (it.value().name == "t4")
899 it.value().alt_name.SetCString("x29");
900 else if (it.value().name == "t5")
901 it.value().alt_name.SetCString("x30");
902 else if (it.value().name == "t6")
903 it.value().alt_name.SetCString("x31");
904
905 // Set generic regnum so lldb knows what the PC, etc is
906 it.value().regnum_generic = GetGenericNum(name: it.value().name.GetStringRef());
907 }
908}
909

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source code of lldb/source/Plugins/ABI/RISCV/ABISysV_riscv.cpp