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