xref: /llvm-project/lldb/source/Plugins/ABI/PowerPC/ABISysV_ppc64.cpp (revision b852fb1ec5fa15f0b913cc4988cbd09239b19904)
1 //===-- ABISysV_ppc64.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_ppc64.h"
10 
11 #include "llvm/ADT/STLExtras.h"
12 #include "llvm/TargetParser/Triple.h"
13 
14 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
15 #include "Utility/PPC64LE_DWARF_Registers.h"
16 #include "Utility/PPC64_DWARF_Registers.h"
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/StackFrame.h"
24 #include "lldb/Target/Target.h"
25 #include "lldb/Target/Thread.h"
26 #include "lldb/Utility/ConstString.h"
27 #include "lldb/Utility/DataExtractor.h"
28 #include "lldb/Utility/LLDBLog.h"
29 #include "lldb/Utility/Log.h"
30 #include "lldb/Utility/RegisterValue.h"
31 #include "lldb/Utility/Status.h"
32 #include "lldb/ValueObject/ValueObjectConstResult.h"
33 #include "lldb/ValueObject/ValueObjectMemory.h"
34 #include "lldb/ValueObject/ValueObjectRegister.h"
35 
36 #include "clang/AST/ASTContext.h"
37 #include "clang/AST/Attr.h"
38 #include "clang/AST/Decl.h"
39 
40 #define DECLARE_REGISTER_INFOS_PPC64_STRUCT
41 #include "Plugins/Process/Utility/RegisterInfos_ppc64.h"
42 #undef DECLARE_REGISTER_INFOS_PPC64_STRUCT
43 
44 #define DECLARE_REGISTER_INFOS_PPC64LE_STRUCT
45 #include "Plugins/Process/Utility/RegisterInfos_ppc64le.h"
46 #undef DECLARE_REGISTER_INFOS_PPC64LE_STRUCT
47 #include <optional>
48 
49 using namespace lldb;
50 using namespace lldb_private;
51 
52 LLDB_PLUGIN_DEFINE(ABISysV_ppc64)
53 
54 const lldb_private::RegisterInfo *
55 ABISysV_ppc64::GetRegisterInfoArray(uint32_t &count) {
56   if (GetByteOrder() == lldb::eByteOrderLittle) {
57     count = std::size(g_register_infos_ppc64le);
58     return g_register_infos_ppc64le;
59   } else {
60     count = std::size(g_register_infos_ppc64);
61     return g_register_infos_ppc64;
62   }
63 }
64 
65 size_t ABISysV_ppc64::GetRedZoneSize() const { return 224; }
66 
67 lldb::ByteOrder ABISysV_ppc64::GetByteOrder() const {
68   return GetProcessSP()->GetByteOrder();
69 }
70 
71 // Static Functions
72 
73 ABISP
74 ABISysV_ppc64::CreateInstance(lldb::ProcessSP process_sp,
75                               const ArchSpec &arch) {
76   if (arch.GetTriple().isPPC64())
77     return ABISP(
78         new ABISysV_ppc64(std::move(process_sp), MakeMCRegisterInfo(arch)));
79   return ABISP();
80 }
81 
82 bool ABISysV_ppc64::PrepareTrivialCall(Thread &thread, addr_t sp,
83                                        addr_t func_addr, addr_t return_addr,
84                                        llvm::ArrayRef<addr_t> args) const {
85   Log *log = GetLog(LLDBLog::Expressions);
86 
87   if (log) {
88     StreamString s;
89     s.Printf("ABISysV_ppc64::PrepareTrivialCall (tid = 0x%" PRIx64
90              ", sp = 0x%" PRIx64 ", func_addr = 0x%" PRIx64
91              ", return_addr = 0x%" PRIx64,
92              thread.GetID(), (uint64_t)sp, (uint64_t)func_addr,
93              (uint64_t)return_addr);
94 
95     for (size_t i = 0; i < args.size(); ++i)
96       s.Printf(", arg%" PRIu64 " = 0x%" PRIx64, static_cast<uint64_t>(i + 1),
97                args[i]);
98     s.PutCString(")");
99     log->PutString(s.GetString());
100   }
101 
102   RegisterContext *reg_ctx = thread.GetRegisterContext().get();
103   if (!reg_ctx)
104     return false;
105 
106   const RegisterInfo *reg_info = nullptr;
107 
108   if (args.size() > 8) // TODO handle more than 8 arguments
109     return false;
110 
111   for (size_t i = 0; i < args.size(); ++i) {
112     reg_info = reg_ctx->GetRegisterInfo(eRegisterKindGeneric,
113                                         LLDB_REGNUM_GENERIC_ARG1 + i);
114     LLDB_LOGF(log, "About to write arg%" PRIu64 " (0x%" PRIx64 ") into %s",
115               static_cast<uint64_t>(i + 1), args[i], reg_info->name);
116     if (!reg_ctx->WriteRegisterFromUnsigned(reg_info, args[i]))
117       return false;
118   }
119 
120   // First, align the SP
121 
122   LLDB_LOGF(log, "16-byte aligning SP: 0x%" PRIx64 " to 0x%" PRIx64,
123             (uint64_t)sp, (uint64_t)(sp & ~0xfull));
124 
125   sp &= ~(0xfull); // 16-byte alignment
126 
127   sp -= 544; // allocate frame to save TOC, RA and SP.
128 
129   Status error;
130   uint64_t reg_value;
131   const RegisterInfo *pc_reg_info =
132       reg_ctx->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
133   const RegisterInfo *sp_reg_info =
134       reg_ctx->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_SP);
135   ProcessSP process_sp(thread.GetProcess());
136   const RegisterInfo *lr_reg_info =
137       reg_ctx->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_RA);
138   const RegisterInfo *r2_reg_info = reg_ctx->GetRegisterInfoAtIndex(2);
139   const RegisterInfo *r12_reg_info = reg_ctx->GetRegisterInfoAtIndex(12);
140 
141   // Save return address onto the stack.
142   LLDB_LOGF(log,
143             "Pushing the return address onto the stack: 0x%" PRIx64
144             "(+16): 0x%" PRIx64,
145             (uint64_t)sp, (uint64_t)return_addr);
146   if (!process_sp->WritePointerToMemory(sp + 16, return_addr, error))
147     return false;
148 
149   // Write the return address to link register.
150   LLDB_LOGF(log, "Writing LR: 0x%" PRIx64, (uint64_t)return_addr);
151   if (!reg_ctx->WriteRegisterFromUnsigned(lr_reg_info, return_addr))
152     return false;
153 
154   // Write target address to %r12 register.
155   LLDB_LOGF(log, "Writing R12: 0x%" PRIx64, (uint64_t)func_addr);
156   if (!reg_ctx->WriteRegisterFromUnsigned(r12_reg_info, func_addr))
157     return false;
158 
159   // Read TOC pointer value.
160   reg_value = reg_ctx->ReadRegisterAsUnsigned(r2_reg_info, 0);
161 
162   // Write TOC pointer onto the stack.
163   uint64_t stack_offset;
164   if (GetByteOrder() == lldb::eByteOrderLittle)
165     stack_offset = 24;
166   else
167     stack_offset = 40;
168 
169   LLDB_LOGF(log, "Writing R2 (TOC) at SP(0x%" PRIx64 ")+%d: 0x%" PRIx64,
170             (uint64_t)(sp + stack_offset), (int)stack_offset,
171             (uint64_t)reg_value);
172   if (!process_sp->WritePointerToMemory(sp + stack_offset, reg_value, error))
173     return false;
174 
175   // Read the current SP value.
176   reg_value = reg_ctx->ReadRegisterAsUnsigned(sp_reg_info, 0);
177 
178   // Save current SP onto the stack.
179   LLDB_LOGF(log, "Writing SP at SP(0x%" PRIx64 ")+0: 0x%" PRIx64, (uint64_t)sp,
180             (uint64_t)reg_value);
181   if (!process_sp->WritePointerToMemory(sp, reg_value, error))
182     return false;
183 
184   // %r1 is set to the actual stack value.
185   LLDB_LOGF(log, "Writing SP: 0x%" PRIx64, (uint64_t)sp);
186 
187   if (!reg_ctx->WriteRegisterFromUnsigned(sp_reg_info, sp))
188     return false;
189 
190   // %pc is set to the address of the called function.
191 
192   LLDB_LOGF(log, "Writing IP: 0x%" PRIx64, (uint64_t)func_addr);
193 
194   if (!reg_ctx->WriteRegisterFromUnsigned(pc_reg_info, func_addr))
195     return false;
196 
197   return true;
198 }
199 
200 static bool ReadIntegerArgument(Scalar &scalar, unsigned int bit_width,
201                                 bool is_signed, Thread &thread,
202                                 uint32_t *argument_register_ids,
203                                 unsigned int &current_argument_register,
204                                 addr_t &current_stack_argument) {
205   if (bit_width > 64)
206     return false; // Scalar can't hold large integer arguments
207 
208   if (current_argument_register < 6) {
209     scalar = thread.GetRegisterContext()->ReadRegisterAsUnsigned(
210         argument_register_ids[current_argument_register], 0);
211     current_argument_register++;
212     if (is_signed)
213       scalar.SignExtend(bit_width);
214   } else {
215     uint32_t byte_size = (bit_width + (8 - 1)) / 8;
216     Status error;
217     if (thread.GetProcess()->ReadScalarIntegerFromMemory(
218             current_stack_argument, byte_size, is_signed, scalar, error)) {
219       current_stack_argument += byte_size;
220       return true;
221     }
222     return false;
223   }
224   return true;
225 }
226 
227 bool ABISysV_ppc64::GetArgumentValues(Thread &thread, ValueList &values) const {
228   unsigned int num_values = values.GetSize();
229   unsigned int value_index;
230 
231   // Extract the register context so we can read arguments from registers
232 
233   RegisterContext *reg_ctx = thread.GetRegisterContext().get();
234 
235   if (!reg_ctx)
236     return false;
237 
238   // Get the pointer to the first stack argument so we have a place to start
239   // when reading data
240 
241   addr_t sp = reg_ctx->GetSP(0);
242 
243   if (!sp)
244     return false;
245 
246   uint64_t stack_offset;
247   if (GetByteOrder() == lldb::eByteOrderLittle)
248     stack_offset = 32;
249   else
250     stack_offset = 48;
251 
252   // jump over return address.
253   addr_t current_stack_argument = sp + stack_offset;
254   uint32_t argument_register_ids[8];
255 
256   for (size_t i = 0; i < 8; ++i) {
257     argument_register_ids[i] =
258         reg_ctx
259             ->GetRegisterInfo(eRegisterKindGeneric,
260                               LLDB_REGNUM_GENERIC_ARG1 + i)
261             ->kinds[eRegisterKindLLDB];
262   }
263 
264   unsigned int current_argument_register = 0;
265 
266   for (value_index = 0; value_index < num_values; ++value_index) {
267     Value *value = values.GetValueAtIndex(value_index);
268 
269     if (!value)
270       return false;
271 
272     // We currently only support extracting values with Clang QualTypes. Do we
273     // care about others?
274     CompilerType compiler_type = value->GetCompilerType();
275     std::optional<uint64_t> bit_size = compiler_type.GetBitSize(&thread);
276     if (!bit_size)
277       return false;
278     bool is_signed;
279 
280     if (compiler_type.IsIntegerOrEnumerationType(is_signed)) {
281       ReadIntegerArgument(value->GetScalar(), *bit_size, is_signed, thread,
282                           argument_register_ids, current_argument_register,
283                           current_stack_argument);
284     } else if (compiler_type.IsPointerType()) {
285       ReadIntegerArgument(value->GetScalar(), *bit_size, false, thread,
286                           argument_register_ids, current_argument_register,
287                           current_stack_argument);
288     }
289   }
290 
291   return true;
292 }
293 
294 Status ABISysV_ppc64::SetReturnValueObject(lldb::StackFrameSP &frame_sp,
295                                            lldb::ValueObjectSP &new_value_sp) {
296   Status error;
297   if (!new_value_sp) {
298     error = Status::FromErrorString("Empty value object for return value.");
299     return error;
300   }
301 
302   CompilerType compiler_type = new_value_sp->GetCompilerType();
303   if (!compiler_type) {
304     error = Status::FromErrorString("Null clang type for return value.");
305     return error;
306   }
307 
308   Thread *thread = frame_sp->GetThread().get();
309 
310   bool is_signed;
311   uint32_t count;
312   bool is_complex;
313 
314   RegisterContext *reg_ctx = thread->GetRegisterContext().get();
315 
316   bool set_it_simple = false;
317   if (compiler_type.IsIntegerOrEnumerationType(is_signed) ||
318       compiler_type.IsPointerType()) {
319     const RegisterInfo *reg_info = reg_ctx->GetRegisterInfoByName("r3", 0);
320 
321     DataExtractor data;
322     Status data_error;
323     size_t num_bytes = new_value_sp->GetData(data, data_error);
324     if (data_error.Fail()) {
325       error = Status::FromErrorStringWithFormat(
326           "Couldn't convert return value to raw data: %s",
327           data_error.AsCString());
328       return error;
329     }
330     lldb::offset_t offset = 0;
331     if (num_bytes <= 8) {
332       uint64_t raw_value = data.GetMaxU64(&offset, num_bytes);
333 
334       if (reg_ctx->WriteRegisterFromUnsigned(reg_info, raw_value))
335         set_it_simple = true;
336     } else {
337       error = Status::FromErrorString(
338           "We don't support returning longer than 64 bit "
339           "integer values at present.");
340     }
341   } else if (compiler_type.IsFloatingPointType(count, is_complex)) {
342     if (is_complex)
343       error = Status::FromErrorString(
344           "We don't support returning complex values at present");
345     else {
346       std::optional<uint64_t> bit_width =
347           compiler_type.GetBitSize(frame_sp.get());
348       if (!bit_width) {
349         error = Status::FromErrorString("can't get size of type");
350         return error;
351       }
352       if (*bit_width <= 64) {
353         DataExtractor data;
354         Status data_error;
355         size_t num_bytes = new_value_sp->GetData(data, data_error);
356         if (data_error.Fail()) {
357           error = Status::FromErrorStringWithFormat(
358               "Couldn't convert return value to raw data: %s",
359               data_error.AsCString());
360           return error;
361         }
362 
363         unsigned char buffer[16];
364         ByteOrder byte_order = data.GetByteOrder();
365 
366         data.CopyByteOrderedData(0, num_bytes, buffer, 16, byte_order);
367         set_it_simple = true;
368       } else {
369         // FIXME - don't know how to do 80 bit long doubles yet.
370         error = Status::FromErrorString(
371             "We don't support returning float values > 64 bits at present");
372       }
373     }
374   }
375 
376   if (!set_it_simple) {
377     // Okay we've got a structure or something that doesn't fit in a simple
378     // register. We should figure out where it really goes, but we don't
379     // support this yet.
380     error = Status::FromErrorString(
381         "We only support setting simple integer and float "
382         "return types at present.");
383   }
384 
385   return error;
386 }
387 
388 //
389 // ReturnValueExtractor
390 //
391 
392 namespace {
393 
394 #define LOG_PREFIX "ReturnValueExtractor: "
395 
396 class ReturnValueExtractor {
397   // This class represents a register, from which data may be extracted.
398   //
399   // It may be constructed by directly specifying its index (where 0 is the
400   // first register used to return values) or by specifying the offset of a
401   // given struct field, in which case the appropriated register index will be
402   // calculated.
403   class Register {
404   public:
405     enum Type {
406       GPR, // General Purpose Register
407       FPR  // Floating Point Register
408     };
409 
410     // main constructor
411     //
412     // offs - field offset in struct
413     Register(Type ty, uint32_t index, uint32_t offs, RegisterContext *reg_ctx,
414              ByteOrder byte_order)
415         : m_index(index), m_offs(offs % sizeof(uint64_t)),
416           m_avail(sizeof(uint64_t) - m_offs), m_type(ty), m_reg_ctx(reg_ctx),
417           m_byte_order(byte_order) {}
418 
419     // explicit index, no offset
420     Register(Type ty, uint32_t index, RegisterContext *reg_ctx,
421              ByteOrder byte_order)
422         : Register(ty, index, 0, reg_ctx, byte_order) {}
423 
424     // GPR, calculate index from offs
425     Register(uint32_t offs, RegisterContext *reg_ctx, ByteOrder byte_order)
426         : Register(GPR, offs / sizeof(uint64_t), offs, reg_ctx, byte_order) {}
427 
428     uint32_t Index() const { return m_index; }
429 
430     // register offset where data is located
431     uint32_t Offs() const { return m_offs; }
432 
433     // available bytes in this register
434     uint32_t Avail() const { return m_avail; }
435 
436     bool IsValid() const {
437       if (m_index > 7) {
438         LLDB_LOG(m_log, LOG_PREFIX
439                  "No more than 8 registers should be used to return values");
440         return false;
441       }
442       return true;
443     }
444 
445     std::string GetName() const {
446       if (m_type == GPR)
447         return ("r" + llvm::Twine(m_index + 3)).str();
448       else
449         return ("f" + llvm::Twine(m_index + 1)).str();
450     }
451 
452     // get raw register data
453     bool GetRawData(uint64_t &raw_data) {
454       const RegisterInfo *reg_info =
455           m_reg_ctx->GetRegisterInfoByName(GetName());
456       if (!reg_info) {
457         LLDB_LOG(m_log, LOG_PREFIX "Failed to get RegisterInfo");
458         return false;
459       }
460 
461       RegisterValue reg_val;
462       if (!m_reg_ctx->ReadRegister(reg_info, reg_val)) {
463         LLDB_LOG(m_log, LOG_PREFIX "ReadRegister() failed");
464         return false;
465       }
466 
467       Status error;
468       uint32_t rc = reg_val.GetAsMemoryData(
469           *reg_info, &raw_data, sizeof(raw_data), m_byte_order, error);
470       if (rc != sizeof(raw_data)) {
471         LLDB_LOG(m_log, LOG_PREFIX "GetAsMemoryData() failed");
472         return false;
473       }
474 
475       return true;
476     }
477 
478   private:
479     uint32_t m_index;
480     uint32_t m_offs;
481     uint32_t m_avail;
482     Type m_type;
483     RegisterContext *m_reg_ctx;
484     ByteOrder m_byte_order;
485     Log *m_log = GetLog(LLDBLog::Expressions);
486   };
487 
488   Register GetGPR(uint32_t index) const {
489     return Register(Register::GPR, index, m_reg_ctx, m_byte_order);
490   }
491 
492   Register GetFPR(uint32_t index) const {
493     return Register(Register::FPR, index, m_reg_ctx, m_byte_order);
494   }
495 
496   Register GetGPRByOffs(uint32_t offs) const {
497     return Register(offs, m_reg_ctx, m_byte_order);
498   }
499 
500 public:
501   // factory
502   static llvm::Expected<ReturnValueExtractor> Create(Thread &thread,
503                                                      CompilerType &type) {
504     RegisterContext *reg_ctx = thread.GetRegisterContext().get();
505     if (!reg_ctx)
506       return llvm::createStringError(LOG_PREFIX
507                                      "Failed to get RegisterContext");
508 
509     ProcessSP process_sp = thread.GetProcess();
510     if (!process_sp)
511       return llvm::createStringError(LOG_PREFIX "GetProcess() failed");
512 
513     return ReturnValueExtractor(thread, type, reg_ctx, process_sp);
514   }
515 
516   // main method: get value of the type specified at construction time
517   ValueObjectSP GetValue() {
518     const uint32_t type_flags = m_type.GetTypeInfo();
519 
520     // call the appropriate type handler
521     ValueSP value_sp;
522     ValueObjectSP valobj_sp;
523     if (type_flags & eTypeIsScalar) {
524       if (type_flags & eTypeIsInteger) {
525         value_sp = GetIntegerValue(0);
526       } else if (type_flags & eTypeIsFloat) {
527         if (type_flags & eTypeIsComplex) {
528           LLDB_LOG(m_log, LOG_PREFIX "Complex numbers are not supported yet");
529           return ValueObjectSP();
530         } else {
531           value_sp = GetFloatValue(m_type, 0);
532         }
533       }
534     } else if (type_flags & eTypeIsPointer) {
535       value_sp = GetPointerValue(0);
536     }
537 
538     if (value_sp) {
539       valobj_sp = ValueObjectConstResult::Create(
540           m_thread.GetStackFrameAtIndex(0).get(), *value_sp, ConstString(""));
541     } else if (type_flags & eTypeIsVector) {
542       valobj_sp = GetVectorValueObject();
543     } else if (type_flags & eTypeIsStructUnion || type_flags & eTypeIsClass) {
544       valobj_sp = GetStructValueObject();
545     }
546 
547     return valobj_sp;
548   }
549 
550 private:
551   // data
552   Thread &m_thread;
553   CompilerType &m_type;
554   uint64_t m_byte_size;
555   std::unique_ptr<DataBufferHeap> m_data_up;
556   int32_t m_src_offs = 0;
557   int32_t m_dst_offs = 0;
558   bool m_packed = false;
559   Log *m_log = GetLog(LLDBLog::Expressions);
560   RegisterContext *m_reg_ctx;
561   ProcessSP m_process_sp;
562   ByteOrder m_byte_order;
563   uint32_t m_addr_size;
564 
565   // methods
566 
567   // constructor
568   ReturnValueExtractor(Thread &thread, CompilerType &type,
569                        RegisterContext *reg_ctx, ProcessSP process_sp)
570       : m_thread(thread), m_type(type),
571         m_byte_size(m_type.GetByteSize(&thread).value_or(0)),
572         m_data_up(new DataBufferHeap(m_byte_size, 0)), m_reg_ctx(reg_ctx),
573         m_process_sp(process_sp), m_byte_order(process_sp->GetByteOrder()),
574         m_addr_size(
575             process_sp->GetTarget().GetArchitecture().GetAddressByteSize()) {}
576 
577   // build a new scalar value
578   ValueSP NewScalarValue(CompilerType &type) {
579     ValueSP value_sp(new Value);
580     value_sp->SetCompilerType(type);
581     value_sp->SetValueType(Value::ValueType::Scalar);
582     return value_sp;
583   }
584 
585   // get an integer value in the specified register
586   ValueSP GetIntegerValue(uint32_t reg_index) {
587     uint64_t raw_value;
588     auto reg = GetGPR(reg_index);
589     if (!reg.GetRawData(raw_value))
590       return ValueSP();
591 
592     // build value from data
593     ValueSP value_sp(NewScalarValue(m_type));
594 
595     uint32_t type_flags = m_type.GetTypeInfo();
596     bool is_signed = (type_flags & eTypeIsSigned) != 0;
597 
598     switch (m_byte_size) {
599     case sizeof(uint64_t):
600       if (is_signed)
601         value_sp->GetScalar() = (int64_t)(raw_value);
602       else
603         value_sp->GetScalar() = (uint64_t)(raw_value);
604       break;
605 
606     case sizeof(uint32_t):
607       if (is_signed)
608         value_sp->GetScalar() = (int32_t)(raw_value & UINT32_MAX);
609       else
610         value_sp->GetScalar() = (uint32_t)(raw_value & UINT32_MAX);
611       break;
612 
613     case sizeof(uint16_t):
614       if (is_signed)
615         value_sp->GetScalar() = (int16_t)(raw_value & UINT16_MAX);
616       else
617         value_sp->GetScalar() = (uint16_t)(raw_value & UINT16_MAX);
618       break;
619 
620     case sizeof(uint8_t):
621       if (is_signed)
622         value_sp->GetScalar() = (int8_t)(raw_value & UINT8_MAX);
623       else
624         value_sp->GetScalar() = (uint8_t)(raw_value & UINT8_MAX);
625       break;
626 
627     default:
628       llvm_unreachable("Invalid integer size");
629     }
630 
631     return value_sp;
632   }
633 
634   // get a floating point value on the specified register
635   ValueSP GetFloatValue(CompilerType &type, uint32_t reg_index) {
636     uint64_t raw_data;
637     auto reg = GetFPR(reg_index);
638     if (!reg.GetRawData(raw_data))
639       return {};
640 
641     // build value from data
642     ValueSP value_sp(NewScalarValue(type));
643 
644     DataExtractor de(&raw_data, sizeof(raw_data), m_byte_order, m_addr_size);
645 
646     lldb::offset_t offset = 0;
647     std::optional<uint64_t> byte_size = type.GetByteSize(m_process_sp.get());
648     if (!byte_size)
649       return {};
650     switch (*byte_size) {
651     case sizeof(float):
652       value_sp->GetScalar() = (float)de.GetDouble(&offset);
653       break;
654 
655     case sizeof(double):
656       value_sp->GetScalar() = de.GetDouble(&offset);
657       break;
658 
659     default:
660       llvm_unreachable("Invalid floating point size");
661     }
662 
663     return value_sp;
664   }
665 
666   // get pointer value from register
667   ValueSP GetPointerValue(uint32_t reg_index) {
668     uint64_t raw_data;
669     auto reg = GetGPR(reg_index);
670     if (!reg.GetRawData(raw_data))
671       return ValueSP();
672 
673     // build value from raw data
674     ValueSP value_sp(NewScalarValue(m_type));
675     value_sp->GetScalar() = raw_data;
676     return value_sp;
677   }
678 
679   // build the ValueObject from our data buffer
680   ValueObjectSP BuildValueObject() {
681     DataExtractor de(DataBufferSP(m_data_up.release()), m_byte_order,
682                      m_addr_size);
683     return ValueObjectConstResult::Create(&m_thread, m_type, ConstString(""),
684                                           de);
685   }
686 
687   // get a vector return value
688   ValueObjectSP GetVectorValueObject() {
689     const uint32_t MAX_VRS = 2;
690 
691     // get first V register used to return values
692     const RegisterInfo *vr[MAX_VRS];
693     vr[0] = m_reg_ctx->GetRegisterInfoByName("vr2");
694     if (!vr[0]) {
695       LLDB_LOG(m_log, LOG_PREFIX "Failed to get vr2 RegisterInfo");
696       return ValueObjectSP();
697     }
698 
699     const uint32_t vr_size = vr[0]->byte_size;
700     size_t vrs = 1;
701     if (m_byte_size > 2 * vr_size) {
702       LLDB_LOG(
703           m_log, LOG_PREFIX
704           "Returning vectors that don't fit in 2 VR regs is not supported");
705       return ValueObjectSP();
706     }
707 
708     // load vr3, if needed
709     if (m_byte_size > vr_size) {
710       vrs++;
711       vr[1] = m_reg_ctx->GetRegisterInfoByName("vr3");
712       if (!vr[1]) {
713         LLDB_LOG(m_log, LOG_PREFIX "Failed to get vr3 RegisterInfo");
714         return ValueObjectSP();
715       }
716     }
717 
718     // Get the whole contents of vector registers and let the logic here
719     // arrange the data properly.
720 
721     RegisterValue vr_val[MAX_VRS];
722     Status error;
723     std::unique_ptr<DataBufferHeap> vr_data(
724         new DataBufferHeap(vrs * vr_size, 0));
725 
726     for (uint32_t i = 0; i < vrs; i++) {
727       if (!m_reg_ctx->ReadRegister(vr[i], vr_val[i])) {
728         LLDB_LOG(m_log, LOG_PREFIX "Failed to read vector register contents");
729         return ValueObjectSP();
730       }
731       if (!vr_val[i].GetAsMemoryData(*vr[i], vr_data->GetBytes() + i * vr_size,
732                                      vr_size, m_byte_order, error)) {
733         LLDB_LOG(m_log, LOG_PREFIX "Failed to extract vector register bytes");
734         return ValueObjectSP();
735       }
736     }
737 
738     // The compiler generated code seems to always put the vector elements at
739     // the end of the vector register, in case they don't occupy all of it.
740     // This offset variable handles this.
741     uint32_t offs = 0;
742     if (m_byte_size < vr_size)
743       offs = vr_size - m_byte_size;
744 
745     // copy extracted data to our buffer
746     memcpy(m_data_up->GetBytes(), vr_data->GetBytes() + offs, m_byte_size);
747     return BuildValueObject();
748   }
749 
750   // get a struct return value
751   ValueObjectSP GetStructValueObject() {
752     // case 1: get from stack
753     if (m_byte_size > 2 * sizeof(uint64_t)) {
754       uint64_t addr;
755       auto reg = GetGPR(0);
756       if (!reg.GetRawData(addr))
757         return {};
758 
759       Status error;
760       size_t rc = m_process_sp->ReadMemory(addr, m_data_up->GetBytes(),
761                                            m_byte_size, error);
762       if (rc != m_byte_size) {
763         LLDB_LOG(m_log, LOG_PREFIX "Failed to read memory pointed by r3");
764         return ValueObjectSP();
765       }
766       return BuildValueObject();
767     }
768 
769     // get number of children
770     const bool omit_empty_base_classes = true;
771     auto n_or_err = m_type.GetNumChildren(omit_empty_base_classes, nullptr);
772     if (!n_or_err) {
773       LLDB_LOG_ERROR(m_log, n_or_err.takeError(), LOG_PREFIX "{0}");
774       return {};
775     }
776     uint32_t n = *n_or_err;
777     if (!n) {
778       LLDB_LOG(m_log, LOG_PREFIX "No children found in struct");
779       return {};
780     }
781 
782     // case 2: homogeneous double or float aggregate
783     CompilerType elem_type;
784     if (m_type.IsHomogeneousAggregate(&elem_type)) {
785       uint32_t type_flags = elem_type.GetTypeInfo();
786       std::optional<uint64_t> elem_size =
787           elem_type.GetByteSize(m_process_sp.get());
788       if (!elem_size)
789         return {};
790       if (type_flags & eTypeIsComplex || !(type_flags & eTypeIsFloat)) {
791         LLDB_LOG(m_log,
792                  LOG_PREFIX "Unexpected type found in homogeneous aggregate");
793         return {};
794       }
795 
796       for (uint32_t i = 0; i < n; i++) {
797         ValueSP val_sp = GetFloatValue(elem_type, i);
798         if (!val_sp)
799           return {};
800 
801         // copy to buffer
802         Status error;
803         size_t rc = val_sp->GetScalar().GetAsMemoryData(
804             m_data_up->GetBytes() + m_dst_offs, *elem_size, m_byte_order,
805             error);
806         if (rc != *elem_size) {
807           LLDB_LOG(m_log, LOG_PREFIX "Failed to get float data");
808           return {};
809         }
810         m_dst_offs += *elem_size;
811       }
812       return BuildValueObject();
813     }
814 
815     // case 3: get from GPRs
816 
817     // first, check if this is a packed struct or not
818     auto ast = m_type.GetTypeSystem().dyn_cast_or_null<TypeSystemClang>();
819     if (ast) {
820       clang::RecordDecl *record_decl = TypeSystemClang::GetAsRecordDecl(m_type);
821 
822       if (record_decl) {
823         auto attrs = record_decl->attrs();
824         for (const auto &attr : attrs) {
825           if (attr->getKind() == clang::attr::Packed) {
826             m_packed = true;
827             break;
828           }
829         }
830       }
831     }
832 
833     LLDB_LOG(m_log, LOG_PREFIX "{0} struct",
834              m_packed ? "packed" : "not packed");
835 
836     for (uint32_t i = 0; i < n; i++) {
837       std::string name;
838       uint32_t size;
839       (void)GetChildType(i, name, size);
840       // NOTE: the offset returned by GetChildCompilerTypeAtIndex()
841       //       can't be used because it never considers alignment bytes
842       //       between struct fields.
843       LLDB_LOG(m_log, LOG_PREFIX "field={0}, size={1}", name, size);
844       if (!ExtractField(size))
845         return ValueObjectSP();
846     }
847 
848     return BuildValueObject();
849   }
850 
851   // extract 'size' bytes at 'offs' from GPRs
852   bool ExtractFromRegs(int32_t offs, uint32_t size, void *buf) {
853     while (size) {
854       auto reg = GetGPRByOffs(offs);
855       if (!reg.IsValid())
856         return false;
857 
858       uint32_t n = std::min(reg.Avail(), size);
859       uint64_t raw_data;
860 
861       if (!reg.GetRawData(raw_data))
862         return false;
863 
864       memcpy(buf, (char *)&raw_data + reg.Offs(), n);
865       offs += n;
866       size -= n;
867       buf = (char *)buf + n;
868     }
869     return true;
870   }
871 
872   // extract one field from GPRs and put it in our buffer
873   bool ExtractField(uint32_t size) {
874     auto reg = GetGPRByOffs(m_src_offs);
875     if (!reg.IsValid())
876       return false;
877 
878     // handle padding
879     if (!m_packed) {
880       uint32_t n = m_src_offs % size;
881 
882       // not 'size' bytes aligned
883       if (n) {
884         LLDB_LOG(m_log,
885                  LOG_PREFIX "Extracting {0} alignment bytes at offset {1}", n,
886                  m_src_offs);
887         // get alignment bytes
888         if (!ExtractFromRegs(m_src_offs, n, m_data_up->GetBytes() + m_dst_offs))
889           return false;
890         m_src_offs += n;
891         m_dst_offs += n;
892       }
893     }
894 
895     // get field
896     LLDB_LOG(m_log, LOG_PREFIX "Extracting {0} field bytes at offset {1}", size,
897              m_src_offs);
898     if (!ExtractFromRegs(m_src_offs, size, m_data_up->GetBytes() + m_dst_offs))
899       return false;
900     m_src_offs += size;
901     m_dst_offs += size;
902     return true;
903   }
904 
905   // get child
906   llvm::Expected<CompilerType> GetChildType(uint32_t i, std::string &name,
907                                             uint32_t &size) {
908     // GetChild constant inputs
909     const bool transparent_pointers = false;
910     const bool omit_empty_base_classes = true;
911     const bool ignore_array_bounds = false;
912     // GetChild output params
913     int32_t child_offs;
914     uint32_t child_bitfield_bit_size;
915     uint32_t child_bitfield_bit_offset;
916     bool child_is_base_class;
917     bool child_is_deref_of_parent;
918     ValueObject *valobj = nullptr;
919     uint64_t language_flags;
920     ExecutionContext exe_ctx;
921     m_thread.CalculateExecutionContext(exe_ctx);
922 
923     return m_type.GetChildCompilerTypeAtIndex(
924         &exe_ctx, i, transparent_pointers, omit_empty_base_classes,
925         ignore_array_bounds, name, size, child_offs, child_bitfield_bit_size,
926         child_bitfield_bit_offset, child_is_base_class,
927         child_is_deref_of_parent, valobj, language_flags);
928   }
929 };
930 
931 #undef LOG_PREFIX
932 
933 } // anonymous namespace
934 
935 ValueObjectSP
936 ABISysV_ppc64::GetReturnValueObjectSimple(Thread &thread,
937                                           CompilerType &type) const {
938   if (!type)
939     return ValueObjectSP();
940 
941   auto exp_extractor = ReturnValueExtractor::Create(thread, type);
942   if (!exp_extractor) {
943     Log *log = GetLog(LLDBLog::Expressions);
944     LLDB_LOG_ERROR(log, exp_extractor.takeError(),
945                    "Extracting return value failed: {0}");
946     return ValueObjectSP();
947   }
948 
949   return exp_extractor.get().GetValue();
950 }
951 
952 ValueObjectSP ABISysV_ppc64::GetReturnValueObjectImpl(
953     Thread &thread, CompilerType &return_compiler_type) const {
954   return GetReturnValueObjectSimple(thread, return_compiler_type);
955 }
956 
957 bool ABISysV_ppc64::CreateFunctionEntryUnwindPlan(UnwindPlan &unwind_plan) {
958   unwind_plan.Clear();
959   unwind_plan.SetRegisterKind(eRegisterKindDWARF);
960 
961   uint32_t lr_reg_num;
962   uint32_t sp_reg_num;
963   uint32_t pc_reg_num;
964 
965   if (GetByteOrder() == lldb::eByteOrderLittle) {
966     lr_reg_num = ppc64le_dwarf::dwarf_lr_ppc64le;
967     sp_reg_num = ppc64le_dwarf::dwarf_r1_ppc64le;
968     pc_reg_num = ppc64le_dwarf::dwarf_pc_ppc64le;
969   } else {
970     lr_reg_num = ppc64_dwarf::dwarf_lr_ppc64;
971     sp_reg_num = ppc64_dwarf::dwarf_r1_ppc64;
972     pc_reg_num = ppc64_dwarf::dwarf_pc_ppc64;
973   }
974 
975   UnwindPlan::RowSP row(new UnwindPlan::Row);
976 
977   // Our Call Frame Address is the stack pointer value
978   row->GetCFAValue().SetIsRegisterPlusOffset(sp_reg_num, 0);
979 
980   // The previous PC is in the LR
981   row->SetRegisterLocationToRegister(pc_reg_num, lr_reg_num, true);
982   unwind_plan.AppendRow(row);
983 
984   // All other registers are the same.
985 
986   unwind_plan.SetSourceName("ppc64 at-func-entry default");
987   unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);
988 
989   return true;
990 }
991 
992 bool ABISysV_ppc64::CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) {
993   unwind_plan.Clear();
994   unwind_plan.SetRegisterKind(eRegisterKindDWARF);
995 
996   uint32_t sp_reg_num;
997   uint32_t pc_reg_num;
998   uint32_t cr_reg_num;
999 
1000   if (GetByteOrder() == lldb::eByteOrderLittle) {
1001     sp_reg_num = ppc64le_dwarf::dwarf_r1_ppc64le;
1002     pc_reg_num = ppc64le_dwarf::dwarf_lr_ppc64le;
1003     cr_reg_num = ppc64le_dwarf::dwarf_cr_ppc64le;
1004   } else {
1005     sp_reg_num = ppc64_dwarf::dwarf_r1_ppc64;
1006     pc_reg_num = ppc64_dwarf::dwarf_lr_ppc64;
1007     cr_reg_num = ppc64_dwarf::dwarf_cr_ppc64;
1008   }
1009 
1010   UnwindPlan::RowSP row(new UnwindPlan::Row);
1011   const int32_t ptr_size = 8;
1012   row->SetUnspecifiedRegistersAreUndefined(true);
1013   row->GetCFAValue().SetIsRegisterDereferenced(sp_reg_num);
1014 
1015   row->SetRegisterLocationToAtCFAPlusOffset(pc_reg_num, ptr_size * 2, true);
1016   row->SetRegisterLocationToIsCFAPlusOffset(sp_reg_num, 0, true);
1017   row->SetRegisterLocationToAtCFAPlusOffset(cr_reg_num, ptr_size, true);
1018 
1019   unwind_plan.AppendRow(row);
1020   unwind_plan.SetSourceName("ppc64 default unwind plan");
1021   unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);
1022   unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
1023   unwind_plan.SetUnwindPlanForSignalTrap(eLazyBoolNo);
1024   unwind_plan.SetReturnAddressRegister(pc_reg_num);
1025   return true;
1026 }
1027 
1028 bool ABISysV_ppc64::RegisterIsVolatile(const RegisterInfo *reg_info) {
1029   return !RegisterIsCalleeSaved(reg_info);
1030 }
1031 
1032 // See "Register Usage" in the
1033 // "System V Application Binary Interface"
1034 // "64-bit PowerPC ELF Application Binary Interface Supplement" current version
1035 // is 2 released 2015 at
1036 // https://members.openpowerfoundation.org/document/dl/576
1037 bool ABISysV_ppc64::RegisterIsCalleeSaved(const RegisterInfo *reg_info) {
1038   if (reg_info) {
1039     // Preserved registers are :
1040     //    r1,r2,r13-r31
1041     //    cr2-cr4 (partially preserved)
1042     //    f14-f31 (not yet)
1043     //    v20-v31 (not yet)
1044     //    vrsave (not yet)
1045 
1046     const char *name = reg_info->name;
1047     if (name[0] == 'r') {
1048       if ((name[1] == '1' || name[1] == '2') && name[2] == '\0')
1049         return true;
1050       if (name[1] == '1' && name[2] > '2')
1051         return true;
1052       if ((name[1] == '2' || name[1] == '3') && name[2] != '\0')
1053         return true;
1054     }
1055 
1056     if (name[0] == 'f' && name[1] >= '0' && name[2] <= '9') {
1057       if (name[2] == '\0')
1058         return false;
1059       if (name[1] == '1' && name[2] >= '4')
1060         return true;
1061       if ((name[1] == '2' || name[1] == '3') && name[2] != '\0')
1062         return true;
1063     }
1064 
1065     if (name[0] == 's' && name[1] == 'p' && name[2] == '\0') // sp
1066       return true;
1067     if (name[0] == 'f' && name[1] == 'p' && name[2] == '\0') // fp
1068       return false;
1069     if (name[0] == 'p' && name[1] == 'c' && name[2] == '\0') // pc
1070       return true;
1071   }
1072   return false;
1073 }
1074 
1075 void ABISysV_ppc64::Initialize() {
1076   PluginManager::RegisterPlugin(
1077       GetPluginNameStatic(), "System V ABI for ppc64 targets", CreateInstance);
1078 }
1079 
1080 void ABISysV_ppc64::Terminate() {
1081   PluginManager::UnregisterPlugin(CreateInstance);
1082 }
1083