1 //===-- IRInterpreter.cpp ---------------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "lldb/Core/DataEncoder.h"
11 #include "lldb/Core/Log.h"
12 #include "lldb/Core/ValueObjectConstResult.h"
13 #include "lldb/Expression/ClangExpressionDeclMap.h"
14 #include "lldb/Expression/IRForTarget.h"
15 #include "lldb/Expression/IRInterpreter.h"
16 
17 #include "llvm/Constants.h"
18 #include "llvm/Function.h"
19 #include "llvm/Instructions.h"
20 #include "llvm/Module.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include "llvm/Target/TargetData.h"
23 
24 #include <map>
25 
26 using namespace llvm;
27 
28 IRInterpreter::IRInterpreter(lldb_private::ClangExpressionDeclMap &decl_map,
29                                            lldb_private::Stream *error_stream) :
30     m_decl_map(decl_map),
31     m_error_stream(error_stream)
32 {
33 
34 }
35 
36 IRInterpreter::~IRInterpreter()
37 {
38 
39 }
40 
41 static std::string
42 PrintValue(const Value *value, bool truncate = false)
43 {
44     std::string s;
45     raw_string_ostream rso(s);
46     value->print(rso);
47     rso.flush();
48     if (truncate)
49         s.resize(s.length() - 1);
50 
51     size_t offset;
52     while ((offset = s.find('\n')) != s.npos)
53         s.erase(offset, 1);
54     while (s[0] == ' ' || s[0] == '\t')
55         s.erase(0, 1);
56 
57     return s;
58 }
59 
60 static std::string
61 PrintType(const Type *type, bool truncate = false)
62 {
63     std::string s;
64     raw_string_ostream rso(s);
65     type->print(rso);
66     rso.flush();
67     if (truncate)
68         s.resize(s.length() - 1);
69     return s;
70 }
71 
72 typedef SHARED_PTR(lldb_private::DataEncoder) DataEncoderSP;
73 typedef SHARED_PTR(lldb_private::DataExtractor) DataExtractorSP;
74 
75 class Memory
76 {
77 public:
78     typedef uint32_t                    index_t;
79 
80     struct Allocation
81     {
82         // m_virtual_address is always the address of the variable in the virtual memory
83         // space provided by Memory.
84         //
85         // m_origin is always non-NULL and describes the source of the data (possibly
86         // m_data if this allocation is the authoritative source).
87         //
88         // Possible value configurations:
89         //
90         // Allocation type  getValueType()          getContextType()            m_origin->GetScalar()       m_data
91         // =========================================================================================================================
92         // FileAddress      eValueTypeFileAddress   eContextTypeInvalid         A location in a binary      NULL
93         //                                                                      image
94         //
95         // LoadAddress      eValueTypeLoadAddress   eContextTypeInvalid         A location in the target's  NULL
96         //                                                                      virtual memory
97         //
98         // Alloca           eValueTypeHostAddress   eContextTypeInvalid         == m_data->GetBytes()       Deleted at end of
99         //                                                                                                  execution
100         //
101         // PersistentVar    eValueTypeHostAddress   eContextTypeClangType       A persistent variable's     NULL
102         //                                                                      location in LLDB's memory
103         //
104         // Register         [ignored]               eContextTypeRegister        [ignored]                   Flushed to the register
105         //                                                                                                  at the end of execution
106 
107         lldb::addr_t        m_virtual_address;
108         size_t              m_extent;
109         lldb_private::Value m_origin;
110         lldb::DataBufferSP  m_data;
111 
112         Allocation (lldb::addr_t virtual_address,
113                     size_t extent,
114                     lldb::DataBufferSP data) :
115             m_virtual_address(virtual_address),
116             m_extent(extent),
117             m_data(data)
118         {
119         }
120 
121         Allocation (const Allocation &allocation) :
122             m_virtual_address(allocation.m_virtual_address),
123             m_extent(allocation.m_extent),
124             m_origin(allocation.m_origin),
125             m_data(allocation.m_data)
126         {
127         }
128     };
129 
130     typedef SHARED_PTR(Allocation)  AllocationSP;
131 
132     struct Region
133     {
134         AllocationSP m_allocation;
135         uint64_t m_base;
136         uint64_t m_extent;
137 
138         Region () :
139             m_allocation(),
140             m_base(0),
141             m_extent(0)
142         {
143         }
144 
145         Region (AllocationSP allocation, uint64_t base, uint64_t extent) :
146             m_allocation(allocation),
147             m_base(base),
148             m_extent(extent)
149         {
150         }
151 
152         Region (const Region &region) :
153             m_allocation(region.m_allocation),
154             m_base(region.m_base),
155             m_extent(region.m_extent)
156         {
157         }
158 
159         bool IsValid ()
160         {
161             return m_allocation != NULL;
162         }
163 
164         bool IsInvalid ()
165         {
166             return m_allocation == NULL;
167         }
168     };
169 
170     typedef std::vector <AllocationSP>          MemoryMap;
171 
172 private:
173     lldb::addr_t        m_addr_base;
174     lldb::addr_t        m_addr_max;
175     MemoryMap           m_memory;
176     lldb::ByteOrder     m_byte_order;
177     lldb::addr_t        m_addr_byte_size;
178     TargetData         &m_target_data;
179 
180     lldb_private::ClangExpressionDeclMap   &m_decl_map;
181 
182     MemoryMap::iterator LookupInternal (lldb::addr_t addr)
183     {
184         for (MemoryMap::iterator i = m_memory.begin(), e = m_memory.end();
185              i != e;
186              ++i)
187         {
188             if ((*i)->m_virtual_address <= addr &&
189                 (*i)->m_virtual_address + (*i)->m_extent > addr)
190                 return i;
191         }
192 
193         return m_memory.end();
194     }
195 
196 public:
197     Memory (TargetData &target_data,
198             lldb_private::ClangExpressionDeclMap &decl_map,
199             lldb::addr_t alloc_start,
200             lldb::addr_t alloc_max) :
201         m_addr_base(alloc_start),
202         m_addr_max(alloc_max),
203         m_target_data(target_data),
204         m_decl_map(decl_map)
205     {
206         m_byte_order = (target_data.isLittleEndian() ? lldb::eByteOrderLittle : lldb::eByteOrderBig);
207         m_addr_byte_size = (target_data.getPointerSize());
208     }
209 
210     Region Malloc (size_t size, size_t align)
211     {
212         lldb::DataBufferSP data(new lldb_private::DataBufferHeap(size, 0));
213 
214         if (data)
215         {
216             index_t index = m_memory.size();
217 
218             const size_t mask = (align - 1);
219 
220             m_addr_base += mask;
221             m_addr_base &= ~mask;
222 
223             if (m_addr_base + size < m_addr_base ||
224                 m_addr_base + size > m_addr_max)
225                 return Region();
226 
227             uint64_t base = m_addr_base;
228 
229             m_memory.push_back(AllocationSP(new Allocation(base, size, data)));
230 
231             m_addr_base += size;
232 
233             AllocationSP alloc = m_memory[index];
234 
235             alloc->m_origin.GetScalar() = (unsigned long long)data->GetBytes();
236             alloc->m_origin.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
237             alloc->m_origin.SetValueType(lldb_private::Value::eValueTypeHostAddress);
238 
239             return Region(alloc, base, size);
240         }
241 
242         return Region();
243     }
244 
245     Region Malloc (Type *type)
246     {
247         return Malloc (m_target_data.getTypeAllocSize(type),
248                        m_target_data.getPrefTypeAlignment(type));
249     }
250 
251     Region Place (Type *type, lldb::addr_t base, lldb_private::Value &value)
252     {
253         index_t index = m_memory.size();
254         size_t size = m_target_data.getTypeAllocSize(type);
255 
256         m_memory.push_back(AllocationSP(new Allocation(base, size, lldb::DataBufferSP())));
257 
258         AllocationSP alloc = m_memory[index];
259 
260         alloc->m_origin = value;
261 
262         return Region(alloc, base, size);
263     }
264 
265     void Free (lldb::addr_t addr)
266     {
267         MemoryMap::iterator i = LookupInternal (addr);
268 
269         if (i != m_memory.end())
270             m_memory.erase(i);
271     }
272 
273     Region Lookup (lldb::addr_t addr, Type *type)
274     {
275         MemoryMap::iterator i = LookupInternal(addr);
276 
277         if (i == m_memory.end() || !type->isSized())
278             return Region();
279 
280         size_t size = m_target_data.getTypeStoreSize(type);
281 
282         return Region(*i, addr, size);
283     }
284 
285     DataEncoderSP GetEncoder (Region region)
286     {
287         if (region.m_allocation->m_origin.GetValueType() != lldb_private::Value::eValueTypeHostAddress)
288             return DataEncoderSP();
289 
290         lldb::DataBufferSP buffer = region.m_allocation->m_data;
291 
292         if (!buffer)
293             return DataEncoderSP();
294 
295         size_t base_offset = (size_t)(region.m_base - region.m_allocation->m_virtual_address);
296 
297         return DataEncoderSP(new lldb_private::DataEncoder(buffer->GetBytes() + base_offset, region.m_extent, m_byte_order, m_addr_byte_size));
298     }
299 
300     DataExtractorSP GetExtractor (Region region)
301     {
302         if (region.m_allocation->m_origin.GetValueType() != lldb_private::Value::eValueTypeHostAddress)
303             return DataExtractorSP();
304 
305         lldb::DataBufferSP buffer = region.m_allocation->m_data;
306         size_t base_offset = (size_t)(region.m_base - region.m_allocation->m_virtual_address);
307 
308         if (buffer)
309             return DataExtractorSP(new lldb_private::DataExtractor(buffer->GetBytes() + base_offset, region.m_extent, m_byte_order, m_addr_byte_size));
310         else
311             return DataExtractorSP(new lldb_private::DataExtractor((uint8_t*)region.m_allocation->m_origin.GetScalar().ULongLong() + base_offset, region.m_extent, m_byte_order, m_addr_byte_size));
312     }
313 
314     lldb_private::Value GetAccessTarget(lldb::addr_t addr)
315     {
316         MemoryMap::iterator i = LookupInternal(addr);
317 
318         if (i == m_memory.end())
319             return lldb_private::Value();
320 
321         lldb_private::Value target = (*i)->m_origin;
322 
323         if (target.GetContextType() == lldb_private::Value::eContextTypeRegisterInfo)
324         {
325             target.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
326             target.SetValueType(lldb_private::Value::eValueTypeHostAddress);
327             target.GetScalar() = (unsigned long long)(*i)->m_data->GetBytes();
328         }
329 
330         target.GetScalar() += (addr - (*i)->m_virtual_address);
331 
332         return target;
333     }
334 
335     bool Write (lldb::addr_t addr, const uint8_t *data, size_t length)
336     {
337         lldb_private::Value target = GetAccessTarget(addr);
338 
339         return m_decl_map.WriteTarget(target, data, length);
340     }
341 
342     bool Read (uint8_t *data, lldb::addr_t addr, size_t length)
343     {
344         lldb_private::Value source = GetAccessTarget(addr);
345 
346         return m_decl_map.ReadTarget(data, source, length);
347     }
348 
349     bool WriteToRawPtr (lldb::addr_t addr, const uint8_t *data, size_t length)
350     {
351         lldb_private::Value target = m_decl_map.WrapBareAddress(addr);
352 
353         return m_decl_map.WriteTarget(target, data, length);
354     }
355 
356     bool ReadFromRawPtr (uint8_t *data, lldb::addr_t addr, size_t length)
357     {
358         lldb_private::Value source = m_decl_map.WrapBareAddress(addr);
359 
360         return m_decl_map.ReadTarget(data, source, length);
361     }
362 
363     std::string PrintData (lldb::addr_t addr, size_t length)
364     {
365         lldb_private::Value target = GetAccessTarget(addr);
366 
367         lldb_private::DataBufferHeap buf(length, 0);
368 
369         if (!m_decl_map.ReadTarget(buf.GetBytes(), target, length))
370             return std::string("<couldn't read data>");
371 
372         lldb_private::StreamString ss;
373 
374         for (size_t i = 0; i < length; i++)
375         {
376             if ((!(i & 0xf)) && i)
377                 ss.Printf("%02hhx - ", buf.GetBytes()[i]);
378             else
379                 ss.Printf("%02hhx ", buf.GetBytes()[i]);
380         }
381 
382         return ss.GetString();
383     }
384 
385     std::string SummarizeRegion (Region &region)
386     {
387         lldb_private::StreamString ss;
388 
389         lldb_private::Value base = GetAccessTarget(region.m_base);
390 
391         ss.Printf("%llx [%s - %s %llx]",
392                   region.m_base,
393                   lldb_private::Value::GetValueTypeAsCString(base.GetValueType()),
394                   lldb_private::Value::GetContextTypeAsCString(base.GetContextType()),
395                   base.GetScalar().ULongLong());
396 
397         ss.Printf(" %s", PrintData(region.m_base, region.m_extent).c_str());
398 
399         return ss.GetString();
400     }
401 };
402 
403 class InterpreterStackFrame
404 {
405 public:
406     typedef std::map <const Value*, Memory::Region> ValueMap;
407 
408     ValueMap                                m_values;
409     Memory                                 &m_memory;
410     TargetData                             &m_target_data;
411     lldb_private::ClangExpressionDeclMap   &m_decl_map;
412     const BasicBlock                       *m_bb;
413     BasicBlock::const_iterator              m_ii;
414     BasicBlock::const_iterator              m_ie;
415 
416     lldb::ByteOrder                         m_byte_order;
417     size_t                                  m_addr_byte_size;
418 
419     InterpreterStackFrame (TargetData &target_data,
420                            Memory &memory,
421                            lldb_private::ClangExpressionDeclMap &decl_map) :
422         m_memory (memory),
423         m_target_data (target_data),
424         m_decl_map (decl_map)
425     {
426         m_byte_order = (target_data.isLittleEndian() ? lldb::eByteOrderLittle : lldb::eByteOrderBig);
427         m_addr_byte_size = (target_data.getPointerSize());
428     }
429 
430     void Jump (const BasicBlock *bb)
431     {
432         m_bb = bb;
433         m_ii = m_bb->begin();
434         m_ie = m_bb->end();
435     }
436 
437     bool Cache (Memory::AllocationSP allocation, Type *type)
438     {
439         if (allocation->m_origin.GetContextType() != lldb_private::Value::eContextTypeRegisterInfo)
440             return false;
441 
442         return m_decl_map.ReadTarget(allocation->m_data->GetBytes(), allocation->m_origin, allocation->m_data->GetByteSize());
443     }
444 
445     std::string SummarizeValue (const Value *value)
446     {
447         lldb_private::StreamString ss;
448 
449         ss.Printf("%s", PrintValue(value).c_str());
450 
451         ValueMap::iterator i = m_values.find(value);
452 
453         if (i != m_values.end())
454         {
455             Memory::Region region = i->second;
456 
457             ss.Printf(" %s", m_memory.SummarizeRegion(region).c_str());
458         }
459 
460         return ss.GetString();
461     }
462 
463     bool AssignToMatchType (lldb_private::Scalar &scalar, uint64_t u64value, Type *type)
464     {
465         size_t type_size = m_target_data.getTypeStoreSize(type);
466 
467         switch (type_size)
468         {
469         case 1:
470             scalar = (uint8_t)u64value;
471             break;
472         case 2:
473             scalar = (uint16_t)u64value;
474             break;
475         case 4:
476             scalar = (uint32_t)u64value;
477             break;
478         case 8:
479             scalar = (uint64_t)u64value;
480             break;
481         default:
482             return false;
483         }
484 
485         return true;
486     }
487 
488     bool EvaluateValue (lldb_private::Scalar &scalar, const Value *value, Module &module)
489     {
490         const Constant *constant = dyn_cast<Constant>(value);
491 
492         if (constant)
493         {
494             if (const ConstantInt *constant_int = dyn_cast<ConstantInt>(constant))
495             {
496                 return AssignToMatchType(scalar, constant_int->getLimitedValue(), value->getType());
497             }
498         }
499         else
500         {
501             Memory::Region region = ResolveValue(value, module);
502             DataExtractorSP value_extractor = m_memory.GetExtractor(region);
503 
504             if (!value_extractor)
505                 return false;
506 
507             size_t value_size = m_target_data.getTypeStoreSize(value->getType());
508 
509             uint32_t offset = 0;
510             uint64_t u64value = value_extractor->GetMaxU64(&offset, value_size);
511 
512             return AssignToMatchType(scalar, u64value, value->getType());
513         }
514 
515         return false;
516     }
517 
518     bool AssignValue (const Value *value, lldb_private::Scalar &scalar, Module &module)
519     {
520         Memory::Region region = ResolveValue (value, module);
521 
522         lldb_private::Scalar cast_scalar;
523 
524         if (!AssignToMatchType(cast_scalar, scalar.GetRawBits64(0), value->getType()))
525             return false;
526 
527         lldb_private::DataBufferHeap buf(cast_scalar.GetByteSize(), 0);
528 
529         lldb_private::Error err;
530 
531         if (!cast_scalar.GetAsMemoryData(buf.GetBytes(), buf.GetByteSize(), m_byte_order, err))
532             return false;
533 
534         DataEncoderSP region_encoder = m_memory.GetEncoder(region);
535 
536         memcpy(region_encoder->GetDataStart(), buf.GetBytes(), buf.GetByteSize());
537 
538         return true;
539     }
540 
541     bool ResolveConstantValue (APInt &value, const Constant *constant)
542     {
543         if (const ConstantInt *constant_int = dyn_cast<ConstantInt>(constant))
544         {
545             value = constant_int->getValue();
546             return true;
547         }
548         else if (const ConstantFP *constant_fp = dyn_cast<ConstantFP>(constant))
549         {
550             value = constant_fp->getValueAPF().bitcastToAPInt();
551             return true;
552         }
553         else if (const ConstantExpr *constant_expr = dyn_cast<ConstantExpr>(constant))
554         {
555             switch (constant_expr->getOpcode())
556             {
557                 default:
558                     return false;
559                 case Instruction::IntToPtr:
560                 case Instruction::BitCast:
561                     return ResolveConstantValue(value, constant_expr->getOperand(0));
562                 case Instruction::GetElementPtr:
563                 {
564                     ConstantExpr::const_op_iterator op_cursor = constant_expr->op_begin();
565                     ConstantExpr::const_op_iterator op_end = constant_expr->op_end();
566 
567                     Constant *base = dyn_cast<Constant>(*op_cursor);
568 
569                     if (!base)
570                         return false;
571 
572                     if (!ResolveConstantValue(value, base))
573                         return false;
574 
575                     op_cursor++;
576 
577                     if (op_cursor == op_end)
578                         return true; // no offset to apply!
579 
580                     SmallVector <Value *, 8> indices (op_cursor, op_end);
581 
582                     uint64_t offset = m_target_data.getIndexedOffset(base->getType(), indices);
583 
584                     const bool is_signed = true;
585                     value += APInt(value.getBitWidth(), offset, is_signed);
586 
587                     return true;
588                 }
589             }
590         }
591 
592         return false;
593     }
594 
595     bool ResolveConstant (Memory::Region &region, const Constant *constant)
596     {
597         APInt resolved_value;
598 
599         if (!ResolveConstantValue(resolved_value, constant))
600             return false;
601 
602         const uint64_t *raw_data = resolved_value.getRawData();
603 
604         size_t constant_size = m_target_data.getTypeStoreSize(constant->getType());
605         return m_memory.Write(region.m_base, (const uint8_t*)raw_data, constant_size);
606     }
607 
608     Memory::Region ResolveValue (const Value *value, Module &module)
609     {
610         ValueMap::iterator i = m_values.find(value);
611 
612         if (i != m_values.end())
613             return i->second;
614 
615         const GlobalValue *global_value = dyn_cast<GlobalValue>(value);
616 
617         // If the variable is indirected through the argument
618         // array then we need to build an extra level of indirection
619         // for it.  This is the default; only magic arguments like
620         // "this", "self", and "_cmd" are direct.
621         bool indirect_variable = true;
622 
623         // Attempt to resolve the value using the program's data.
624         // If it is, the values to be created are:
625         //
626         // data_region - a region of memory in which the variable's data resides.
627         // ref_region - a region of memory in which its address (i.e., &var) resides.
628         //   In the JIT case, this region would be a member of the struct passed in.
629         // pointer_region - a region of memory in which the address of the pointer
630         //   resides.  This is an IR-level variable.
631         do
632         {
633             lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
634 
635             lldb_private::Value resolved_value;
636 
637             if (global_value)
638             {
639                 clang::NamedDecl *decl = IRForTarget::DeclForGlobal(global_value, &module);
640 
641                 if (!decl)
642                     break;
643 
644                 if (isa<clang::FunctionDecl>(decl))
645                 {
646                     if (log)
647                         log->Printf("The interpreter does not handle function pointers at the moment");
648 
649                     return Memory::Region();
650                 }
651 
652                 resolved_value = m_decl_map.LookupDecl(decl);
653             }
654             else
655             {
656                 // Special-case "this", "self", and "_cmd"
657 
658                 std::string name_str = value->getName().str();
659 
660                 if (name_str == "this" ||
661                     name_str == "self" ||
662                     name_str == "_cmd")
663                     resolved_value = m_decl_map.GetSpecialValue(lldb_private::ConstString(name_str.c_str()));
664 
665                 indirect_variable = false;
666             }
667 
668             if (resolved_value.GetScalar().GetType() != lldb_private::Scalar::e_void)
669             {
670                 if (resolved_value.GetContextType() == lldb_private::Value::eContextTypeRegisterInfo)
671                 {
672                     Memory::Region data_region = m_memory.Malloc(value->getType());
673                     data_region.m_allocation->m_origin = resolved_value;
674                     Memory::Region ref_region = m_memory.Malloc(value->getType());
675                     Memory::Region pointer_region;
676 
677                     if (indirect_variable)
678                         pointer_region = m_memory.Malloc(value->getType());
679 
680                     if (!Cache(data_region.m_allocation, value->getType()))
681                         return Memory::Region();
682 
683                     if (ref_region.IsInvalid())
684                         return Memory::Region();
685 
686                     if (pointer_region.IsInvalid() && indirect_variable)
687                         return Memory::Region();
688 
689                     DataEncoderSP ref_encoder = m_memory.GetEncoder(ref_region);
690 
691                     if (ref_encoder->PutAddress(0, data_region.m_base) == UINT32_MAX)
692                         return Memory::Region();
693 
694                     if (log)
695                     {
696                         log->Printf("Made an allocation for register variable %s", PrintValue(value).c_str());
697                         log->Printf("  Data contents  : %s", m_memory.PrintData(data_region.m_base, data_region.m_extent).c_str());
698                         log->Printf("  Data region    : %llx", (unsigned long long)data_region.m_base);
699                         log->Printf("  Ref region     : %llx", (unsigned long long)ref_region.m_base);
700                         if (indirect_variable)
701                             log->Printf("  Pointer region : %llx", (unsigned long long)pointer_region.m_base);
702                     }
703 
704                     if (indirect_variable)
705                     {
706                         DataEncoderSP pointer_encoder = m_memory.GetEncoder(pointer_region);
707 
708                         if (pointer_encoder->PutAddress(0, ref_region.m_base) == UINT32_MAX)
709                             return Memory::Region();
710 
711                         m_values[value] = pointer_region;
712                         return pointer_region;
713                     }
714                     else
715                     {
716                         m_values[value] = ref_region;
717                         return ref_region;
718                     }
719                 }
720                 else
721                 {
722                     Memory::Region data_region = m_memory.Place(value->getType(), resolved_value.GetScalar().ULongLong(), resolved_value);
723                     Memory::Region ref_region = m_memory.Malloc(value->getType());
724                     Memory::Region pointer_region;
725 
726                     if (indirect_variable)
727                         pointer_region = m_memory.Malloc(value->getType());
728 
729                     if (ref_region.IsInvalid())
730                         return Memory::Region();
731 
732                     if (pointer_region.IsInvalid() && indirect_variable)
733                         return Memory::Region();
734 
735                     DataEncoderSP ref_encoder = m_memory.GetEncoder(ref_region);
736 
737                     if (ref_encoder->PutAddress(0, data_region.m_base) == UINT32_MAX)
738                         return Memory::Region();
739 
740                     if (indirect_variable)
741                     {
742                         DataEncoderSP pointer_encoder = m_memory.GetEncoder(pointer_region);
743 
744                         if (pointer_encoder->PutAddress(0, ref_region.m_base) == UINT32_MAX)
745                             return Memory::Region();
746 
747                         m_values[value] = pointer_region;
748                     }
749 
750                     if (log)
751                     {
752                         log->Printf("Made an allocation for %s", PrintValue(value).c_str());
753                         log->Printf("  Data contents  : %s", m_memory.PrintData(data_region.m_base, data_region.m_extent).c_str());
754                         log->Printf("  Data region    : %llx", (unsigned long long)data_region.m_base);
755                         log->Printf("  Ref region     : %llx", (unsigned long long)ref_region.m_base);
756                         if (indirect_variable)
757                             log->Printf("  Pointer region : %llx", (unsigned long long)pointer_region.m_base);
758                     }
759 
760                     if (indirect_variable)
761                         return pointer_region;
762                     else
763                         return ref_region;
764                 }
765             }
766         }
767         while(0);
768 
769         // Fall back and allocate space [allocation type Alloca]
770 
771         Type *type = value->getType();
772 
773         lldb::ValueSP backing_value(new lldb_private::Value);
774 
775         Memory::Region data_region = m_memory.Malloc(type);
776         data_region.m_allocation->m_origin.GetScalar() = (unsigned long long)data_region.m_allocation->m_data->GetBytes();
777         data_region.m_allocation->m_origin.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
778         data_region.m_allocation->m_origin.SetValueType(lldb_private::Value::eValueTypeHostAddress);
779 
780         const Constant *constant = dyn_cast<Constant>(value);
781 
782         do
783         {
784             if (!constant)
785                 break;
786 
787             if (!ResolveConstant (data_region, constant))
788                 return Memory::Region();
789         }
790         while(0);
791 
792         m_values[value] = data_region;
793         return data_region;
794     }
795 
796     bool ConstructResult (lldb::ClangExpressionVariableSP &result,
797                           const GlobalValue *result_value,
798                           const lldb_private::ConstString &result_name,
799                           lldb_private::TypeFromParser result_type,
800                           Module &module)
801     {
802         // The result_value resolves to P, a pointer to a region R containing the result data.
803         // If the result variable is a reference, the region R contains a pointer to the result R_final in the original process.
804 
805         if (!result_value)
806             return true; // There was no slot for a result – the expression doesn't return one.
807 
808         ValueMap::iterator i = m_values.find(result_value);
809 
810         if (i == m_values.end())
811             return false; // There was a slot for the result, but we didn't write into it.
812 
813         Memory::Region P = i->second;
814         DataExtractorSP P_extractor = m_memory.GetExtractor(P);
815 
816         if (!P_extractor)
817             return false;
818 
819         Type *pointer_ty = result_value->getType();
820         PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
821         if (!pointer_ptr_ty)
822             return false;
823         Type *R_ty = pointer_ptr_ty->getElementType();
824 
825         uint32_t offset = 0;
826         lldb::addr_t pointer = P_extractor->GetAddress(&offset);
827 
828         Memory::Region R = m_memory.Lookup(pointer, R_ty);
829 
830         if (R.m_allocation->m_origin.GetValueType() != lldb_private::Value::eValueTypeHostAddress ||
831             !R.m_allocation->m_data)
832             return false;
833 
834         lldb_private::Value base;
835 
836         bool transient = false;
837         bool maybe_make_load = false;
838 
839         if (m_decl_map.ResultIsReference(result_name))
840         {
841             PointerType *R_ptr_ty = dyn_cast<PointerType>(R_ty);
842             if (!R_ptr_ty)
843                 return false;
844             Type *R_final_ty = R_ptr_ty->getElementType();
845 
846             DataExtractorSP R_extractor = m_memory.GetExtractor(R);
847 
848             if (!R_extractor)
849                 return false;
850 
851             offset = 0;
852             lldb::addr_t R_pointer = R_extractor->GetAddress(&offset);
853 
854             Memory::Region R_final = m_memory.Lookup(R_pointer, R_final_ty);
855 
856             if (R_final.m_allocation)
857             {
858                 if (R_final.m_allocation->m_data)
859                     transient = true; // this is a stack allocation
860 
861                 base = R_final.m_allocation->m_origin;
862                 base.GetScalar() += (R_final.m_base - R_final.m_allocation->m_virtual_address);
863             }
864             else
865             {
866                 // We got a bare pointer.  We are going to treat it as a load address
867                 // or a file address, letting decl_map make the choice based on whether
868                 // or not a process exists.
869 
870                 base.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
871                 base.SetValueType(lldb_private::Value::eValueTypeFileAddress);
872                 base.GetScalar() = (unsigned long long)R_pointer;
873                 maybe_make_load = true;
874             }
875         }
876         else
877         {
878             base.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
879             base.SetValueType(lldb_private::Value::eValueTypeHostAddress);
880             base.GetScalar() = (unsigned long long)R.m_allocation->m_data->GetBytes() + (R.m_base - R.m_allocation->m_virtual_address);
881         }
882 
883         return m_decl_map.CompleteResultVariable (result, base, result_name, result_type, transient, maybe_make_load);
884     }
885 };
886 
887 bool
888 IRInterpreter::maybeRunOnFunction (lldb::ClangExpressionVariableSP &result,
889                                    const lldb_private::ConstString &result_name,
890                                    lldb_private::TypeFromParser result_type,
891                                    Function &llvm_function,
892                                    Module &llvm_module,
893                                    lldb_private::Error &err)
894 {
895     if (supportsFunction (llvm_function, err))
896         return runOnFunction(result,
897                              result_name,
898                              result_type,
899                              llvm_function,
900                              llvm_module,
901                              err);
902     else
903         return false;
904 }
905 
906 static const char *unsupported_opcode_error         = "Interpreter doesn't handle one of the expression's opcodes";
907 static const char *interpreter_initialization_error = "Interpreter couldn't be initialized";
908 static const char *interpreter_internal_error       = "Interpreter encountered an internal error";
909 static const char *bad_value_error                  = "Interpreter couldn't resolve a value during execution";
910 static const char *memory_allocation_error          = "Interpreter couldn't allocate memory";
911 static const char *memory_write_error               = "Interpreter couldn't write to memory";
912 static const char *memory_read_error                = "Interpreter couldn't read from memory";
913 static const char *infinite_loop_error              = "Interpreter ran for too many cycles";
914 static const char *bad_result_error                 = "Result of expression is in bad memory";
915 
916 bool
917 IRInterpreter::supportsFunction (Function &llvm_function,
918                                  lldb_private::Error &err)
919 {
920     lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
921 
922     for (Function::iterator bbi = llvm_function.begin(), bbe = llvm_function.end();
923          bbi != bbe;
924          ++bbi)
925     {
926         for (BasicBlock::iterator ii = bbi->begin(), ie = bbi->end();
927              ii != ie;
928              ++ii)
929         {
930             switch (ii->getOpcode())
931             {
932             default:
933                 {
934                     if (log)
935                         log->Printf("Unsupported instruction: %s", PrintValue(ii).c_str());
936                     err.SetErrorToGenericError();
937                     err.SetErrorString(unsupported_opcode_error);
938                     return false;
939                 }
940             case Instruction::Add:
941             case Instruction::Alloca:
942             case Instruction::BitCast:
943             case Instruction::Br:
944             case Instruction::GetElementPtr:
945                 break;
946             case Instruction::ICmp:
947                 {
948                     ICmpInst *icmp_inst = dyn_cast<ICmpInst>(ii);
949 
950                     if (!icmp_inst)
951                     {
952                         err.SetErrorToGenericError();
953                         err.SetErrorString(interpreter_internal_error);
954                         return false;
955                     }
956 
957                     switch (icmp_inst->getPredicate())
958                     {
959                     default:
960                         {
961                             if (log)
962                                 log->Printf("Unsupported ICmp predicate: %s", PrintValue(ii).c_str());
963 
964                             err.SetErrorToGenericError();
965                             err.SetErrorString(unsupported_opcode_error);
966                             return false;
967                         }
968                     case CmpInst::ICMP_EQ:
969                     case CmpInst::ICMP_NE:
970                     case CmpInst::ICMP_UGT:
971                     case CmpInst::ICMP_UGE:
972                     case CmpInst::ICMP_ULT:
973                     case CmpInst::ICMP_ULE:
974                     case CmpInst::ICMP_SGT:
975                     case CmpInst::ICMP_SGE:
976                     case CmpInst::ICMP_SLT:
977                     case CmpInst::ICMP_SLE:
978                         break;
979                     }
980                 }
981                 break;
982             case Instruction::IntToPtr:
983             case Instruction::Load:
984             case Instruction::Mul:
985             case Instruction::Ret:
986             case Instruction::SDiv:
987             case Instruction::Store:
988             case Instruction::Sub:
989             case Instruction::UDiv:
990                 break;
991             }
992         }
993     }
994 
995     return true;
996 }
997 
998 bool
999 IRInterpreter::runOnFunction (lldb::ClangExpressionVariableSP &result,
1000                               const lldb_private::ConstString &result_name,
1001                               lldb_private::TypeFromParser result_type,
1002                               Function &llvm_function,
1003                               Module &llvm_module,
1004                               lldb_private::Error &err)
1005 {
1006     lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
1007 
1008     lldb_private::ClangExpressionDeclMap::TargetInfo target_info = m_decl_map.GetTargetInfo();
1009 
1010     if (!target_info.IsValid())
1011     {
1012         err.SetErrorToGenericError();
1013         err.SetErrorString(interpreter_initialization_error);
1014         return false;
1015     }
1016 
1017     lldb::addr_t alloc_min;
1018     lldb::addr_t alloc_max;
1019 
1020     switch (target_info.address_byte_size)
1021     {
1022     default:
1023         err.SetErrorToGenericError();
1024         err.SetErrorString(interpreter_initialization_error);
1025         return false;
1026     case 4:
1027         alloc_min = 0x00001000llu;
1028         alloc_max = 0x0000ffffllu;
1029         break;
1030     case 8:
1031         alloc_min = 0x0000000000001000llu;
1032         alloc_max = 0x000000000000ffffllu;
1033         break;
1034     }
1035 
1036     TargetData target_data(&llvm_module);
1037     if (target_data.getPointerSize() != target_info.address_byte_size)
1038     {
1039         err.SetErrorToGenericError();
1040         err.SetErrorString(interpreter_initialization_error);
1041         return false;
1042     }
1043     if (target_data.isLittleEndian() != (target_info.byte_order == lldb::eByteOrderLittle))
1044     {
1045         err.SetErrorToGenericError();
1046         err.SetErrorString(interpreter_initialization_error);
1047         return false;
1048     }
1049 
1050     Memory memory(target_data, m_decl_map, alloc_min, alloc_max);
1051     InterpreterStackFrame frame(target_data, memory, m_decl_map);
1052 
1053     uint32_t num_insts = 0;
1054 
1055     frame.Jump(llvm_function.begin());
1056 
1057     while (frame.m_ii != frame.m_ie && (++num_insts < 4096))
1058     {
1059         const Instruction *inst = frame.m_ii;
1060 
1061         if (log)
1062             log->Printf("Interpreting %s", PrintValue(inst).c_str());
1063 
1064         switch (inst->getOpcode())
1065         {
1066         default:
1067             break;
1068         case Instruction::Add:
1069         case Instruction::Sub:
1070         case Instruction::Mul:
1071         case Instruction::SDiv:
1072         case Instruction::UDiv:
1073             {
1074                 const BinaryOperator *bin_op = dyn_cast<BinaryOperator>(inst);
1075 
1076                 if (!bin_op)
1077                 {
1078                     if (log)
1079                         log->Printf("getOpcode() returns %s, but instruction is not a BinaryOperator", inst->getOpcodeName());
1080                     err.SetErrorToGenericError();
1081                     err.SetErrorString(interpreter_internal_error);
1082                     return false;
1083                 }
1084 
1085                 Value *lhs = inst->getOperand(0);
1086                 Value *rhs = inst->getOperand(1);
1087 
1088                 lldb_private::Scalar L;
1089                 lldb_private::Scalar R;
1090 
1091                 if (!frame.EvaluateValue(L, lhs, llvm_module))
1092                 {
1093                     if (log)
1094                         log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
1095                     err.SetErrorToGenericError();
1096                     err.SetErrorString(bad_value_error);
1097                     return false;
1098                 }
1099 
1100                 if (!frame.EvaluateValue(R, rhs, llvm_module))
1101                 {
1102                     if (log)
1103                         log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
1104                     err.SetErrorToGenericError();
1105                     err.SetErrorString(bad_value_error);
1106                     return false;
1107                 }
1108 
1109                 lldb_private::Scalar result;
1110 
1111                 switch (inst->getOpcode())
1112                 {
1113                 default:
1114                     break;
1115                 case Instruction::Add:
1116                     result = L + R;
1117                     break;
1118                 case Instruction::Mul:
1119                     result = L * R;
1120                     break;
1121                 case Instruction::Sub:
1122                     result = L - R;
1123                     break;
1124                 case Instruction::SDiv:
1125                     result = L / R;
1126                     break;
1127                 case Instruction::UDiv:
1128                     result = L.GetRawBits64(0) / R.GetRawBits64(1);
1129                     break;
1130                 }
1131 
1132                 frame.AssignValue(inst, result, llvm_module);
1133 
1134                 if (log)
1135                 {
1136                     log->Printf("Interpreted a %s", inst->getOpcodeName());
1137                     log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
1138                     log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
1139                     log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
1140                 }
1141             }
1142             break;
1143         case Instruction::Alloca:
1144             {
1145                 const AllocaInst *alloca_inst = dyn_cast<AllocaInst>(inst);
1146 
1147                 if (!alloca_inst)
1148                 {
1149                     if (log)
1150                         log->Printf("getOpcode() returns Alloca, but instruction is not an AllocaInst");
1151                     err.SetErrorToGenericError();
1152                     err.SetErrorString(interpreter_internal_error);
1153                     return false;
1154                 }
1155 
1156                 if (alloca_inst->isArrayAllocation())
1157                 {
1158                     if (log)
1159                         log->Printf("AllocaInsts are not handled if isArrayAllocation() is true");
1160                     err.SetErrorToGenericError();
1161                     err.SetErrorString(unsupported_opcode_error);
1162                     return false;
1163                 }
1164 
1165                 // The semantics of Alloca are:
1166                 //   Create a region R of virtual memory of type T, backed by a data buffer
1167                 //   Create a region P of virtual memory of type T*, backed by a data buffer
1168                 //   Write the virtual address of R into P
1169 
1170                 Type *T = alloca_inst->getAllocatedType();
1171                 Type *Tptr = alloca_inst->getType();
1172 
1173                 Memory::Region R = memory.Malloc(T);
1174 
1175                 if (R.IsInvalid())
1176                 {
1177                     if (log)
1178                         log->Printf("Couldn't allocate memory for an AllocaInst");
1179                     err.SetErrorToGenericError();
1180                     err.SetErrorString(memory_allocation_error);
1181                     return false;
1182                 }
1183 
1184                 Memory::Region P = memory.Malloc(Tptr);
1185 
1186                 if (P.IsInvalid())
1187                 {
1188                     if (log)
1189                         log->Printf("Couldn't allocate the result pointer for an AllocaInst");
1190                     err.SetErrorToGenericError();
1191                     err.SetErrorString(memory_allocation_error);
1192                     return false;
1193                 }
1194 
1195                 DataEncoderSP P_encoder = memory.GetEncoder(P);
1196 
1197                 if (P_encoder->PutAddress(0, R.m_base) == UINT32_MAX)
1198                 {
1199                     if (log)
1200                         log->Printf("Couldn't write the result pointer for an AllocaInst");
1201                     err.SetErrorToGenericError();
1202                     err.SetErrorString(memory_write_error);
1203                     return false;
1204                 }
1205 
1206                 frame.m_values[alloca_inst] = P;
1207 
1208                 if (log)
1209                 {
1210                     log->Printf("Interpreted an AllocaInst");
1211                     log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1212                     log->Printf("  P : %s", frame.SummarizeValue(alloca_inst).c_str());
1213                 }
1214             }
1215             break;
1216         case Instruction::BitCast:
1217             {
1218                 const BitCastInst *bit_cast_inst = dyn_cast<BitCastInst>(inst);
1219 
1220                 if (!bit_cast_inst)
1221                 {
1222                     if (log)
1223                         log->Printf("getOpcode() returns BitCast, but instruction is not a BitCastInst");
1224                     err.SetErrorToGenericError();
1225                     err.SetErrorString(interpreter_internal_error);
1226                     return false;
1227                 }
1228 
1229                 Value *source = bit_cast_inst->getOperand(0);
1230 
1231                 lldb_private::Scalar S;
1232 
1233                 if (!frame.EvaluateValue(S, source, llvm_module))
1234                 {
1235                     if (log)
1236                         log->Printf("Couldn't evaluate %s", PrintValue(source).c_str());
1237                     err.SetErrorToGenericError();
1238                     err.SetErrorString(bad_value_error);
1239                     return false;
1240                 }
1241 
1242                 frame.AssignValue(inst, S, llvm_module);
1243             }
1244             break;
1245         case Instruction::Br:
1246             {
1247                 const BranchInst *br_inst = dyn_cast<BranchInst>(inst);
1248 
1249                 if (!br_inst)
1250                 {
1251                     if (log)
1252                         log->Printf("getOpcode() returns Br, but instruction is not a BranchInst");
1253                     err.SetErrorToGenericError();
1254                     err.SetErrorString(interpreter_internal_error);
1255                     return false;
1256                 }
1257 
1258                 if (br_inst->isConditional())
1259                 {
1260                     Value *condition = br_inst->getCondition();
1261 
1262                     lldb_private::Scalar C;
1263 
1264                     if (!frame.EvaluateValue(C, condition, llvm_module))
1265                     {
1266                         if (log)
1267                             log->Printf("Couldn't evaluate %s", PrintValue(condition).c_str());
1268                         err.SetErrorToGenericError();
1269                         err.SetErrorString(bad_value_error);
1270                         return false;
1271                     }
1272 
1273                     if (C.GetRawBits64(0))
1274                         frame.Jump(br_inst->getSuccessor(0));
1275                     else
1276                         frame.Jump(br_inst->getSuccessor(1));
1277 
1278                     if (log)
1279                     {
1280                         log->Printf("Interpreted a BrInst with a condition");
1281                         log->Printf("  cond : %s", frame.SummarizeValue(condition).c_str());
1282                     }
1283                 }
1284                 else
1285                 {
1286                     frame.Jump(br_inst->getSuccessor(0));
1287 
1288                     if (log)
1289                     {
1290                         log->Printf("Interpreted a BrInst with no condition");
1291                     }
1292                 }
1293             }
1294             continue;
1295         case Instruction::GetElementPtr:
1296             {
1297                 const GetElementPtrInst *gep_inst = dyn_cast<GetElementPtrInst>(inst);
1298 
1299                 if (!gep_inst)
1300                 {
1301                     if (log)
1302                         log->Printf("getOpcode() returns GetElementPtr, but instruction is not a GetElementPtrInst");
1303                     err.SetErrorToGenericError();
1304                     err.SetErrorString(interpreter_internal_error);
1305                     return false;
1306                 }
1307 
1308                 const Value *pointer_operand = gep_inst->getPointerOperand();
1309                 Type *pointer_type = pointer_operand->getType();
1310 
1311                 lldb_private::Scalar P;
1312 
1313                 if (!frame.EvaluateValue(P, pointer_operand, llvm_module))
1314                 {
1315                     if (log)
1316                         log->Printf("Couldn't evaluate %s", PrintValue(pointer_operand).c_str());
1317                     err.SetErrorToGenericError();
1318                     err.SetErrorString(bad_value_error);
1319                     return false;
1320                 }
1321 
1322                 SmallVector <Value *, 8> indices (gep_inst->idx_begin(),
1323                                                   gep_inst->idx_end());
1324 
1325                 uint64_t offset = target_data.getIndexedOffset(pointer_type, indices);
1326 
1327                 lldb_private::Scalar Poffset = P + offset;
1328 
1329                 frame.AssignValue(inst, Poffset, llvm_module);
1330 
1331                 if (log)
1332                 {
1333                     log->Printf("Interpreted a GetElementPtrInst");
1334                     log->Printf("  P       : %s", frame.SummarizeValue(pointer_operand).c_str());
1335                     log->Printf("  Poffset : %s", frame.SummarizeValue(inst).c_str());
1336                 }
1337             }
1338             break;
1339         case Instruction::ICmp:
1340             {
1341                 const ICmpInst *icmp_inst = dyn_cast<ICmpInst>(inst);
1342 
1343                 if (!icmp_inst)
1344                 {
1345                     if (log)
1346                         log->Printf("getOpcode() returns ICmp, but instruction is not an ICmpInst");
1347                     err.SetErrorToGenericError();
1348                     err.SetErrorString(interpreter_internal_error);
1349                     return false;
1350                 }
1351 
1352                 CmpInst::Predicate predicate = icmp_inst->getPredicate();
1353 
1354                 Value *lhs = inst->getOperand(0);
1355                 Value *rhs = inst->getOperand(1);
1356 
1357                 lldb_private::Scalar L;
1358                 lldb_private::Scalar R;
1359 
1360                 if (!frame.EvaluateValue(L, lhs, llvm_module))
1361                 {
1362                     if (log)
1363                         log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
1364                     err.SetErrorToGenericError();
1365                     err.SetErrorString(bad_value_error);
1366                     return false;
1367                 }
1368 
1369                 if (!frame.EvaluateValue(R, rhs, llvm_module))
1370                 {
1371                     if (log)
1372                         log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
1373                     err.SetErrorToGenericError();
1374                     err.SetErrorString(bad_value_error);
1375                     return false;
1376                 }
1377 
1378                 lldb_private::Scalar result;
1379 
1380                 switch (predicate)
1381                 {
1382                 default:
1383                     return false;
1384                 case CmpInst::ICMP_EQ:
1385                     result = (L == R);
1386                     break;
1387                 case CmpInst::ICMP_NE:
1388                     result = (L != R);
1389                     break;
1390                 case CmpInst::ICMP_UGT:
1391                     result = (L.GetRawBits64(0) > R.GetRawBits64(0));
1392                     break;
1393                 case CmpInst::ICMP_UGE:
1394                     result = (L.GetRawBits64(0) >= R.GetRawBits64(0));
1395                     break;
1396                 case CmpInst::ICMP_ULT:
1397                     result = (L.GetRawBits64(0) < R.GetRawBits64(0));
1398                     break;
1399                 case CmpInst::ICMP_ULE:
1400                     result = (L.GetRawBits64(0) <= R.GetRawBits64(0));
1401                     break;
1402                 case CmpInst::ICMP_SGT:
1403                     result = (L > R);
1404                     break;
1405                 case CmpInst::ICMP_SGE:
1406                     result = (L >= R);
1407                     break;
1408                 case CmpInst::ICMP_SLT:
1409                     result = (L < R);
1410                     break;
1411                 case CmpInst::ICMP_SLE:
1412                     result = (L <= R);
1413                     break;
1414                 }
1415 
1416                 frame.AssignValue(inst, result, llvm_module);
1417 
1418                 if (log)
1419                 {
1420                     log->Printf("Interpreted an ICmpInst");
1421                     log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
1422                     log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
1423                     log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
1424                 }
1425             }
1426             break;
1427         case Instruction::IntToPtr:
1428             {
1429                 const IntToPtrInst *int_to_ptr_inst = dyn_cast<IntToPtrInst>(inst);
1430 
1431                 if (!int_to_ptr_inst)
1432                 {
1433                     if (log)
1434                         log->Printf("getOpcode() returns IntToPtr, but instruction is not an IntToPtrInst");
1435                     err.SetErrorToGenericError();
1436                     err.SetErrorString(interpreter_internal_error);
1437                     return false;
1438                 }
1439 
1440                 Value *src_operand = int_to_ptr_inst->getOperand(0);
1441 
1442                 lldb_private::Scalar I;
1443 
1444                 if (!frame.EvaluateValue(I, src_operand, llvm_module))
1445                 {
1446                     if (log)
1447                         log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
1448                     err.SetErrorToGenericError();
1449                     err.SetErrorString(bad_value_error);
1450                     return false;
1451                 }
1452 
1453                 frame.AssignValue(inst, I, llvm_module);
1454 
1455                 if (log)
1456                 {
1457                     log->Printf("Interpreted an IntToPtr");
1458                     log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1459                     log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1460                 }
1461             }
1462             break;
1463         case Instruction::Load:
1464             {
1465                 const LoadInst *load_inst = dyn_cast<LoadInst>(inst);
1466 
1467                 if (!load_inst)
1468                 {
1469                     if (log)
1470                         log->Printf("getOpcode() returns Load, but instruction is not a LoadInst");
1471                     err.SetErrorToGenericError();
1472                     err.SetErrorString(interpreter_internal_error);
1473                     return false;
1474                 }
1475 
1476                 // The semantics of Load are:
1477                 //   Create a region D that will contain the loaded data
1478                 //   Resolve the region P containing a pointer
1479                 //   Dereference P to get the region R that the data should be loaded from
1480                 //   Transfer a unit of type type(D) from R to D
1481 
1482                 const Value *pointer_operand = load_inst->getPointerOperand();
1483 
1484                 Type *pointer_ty = pointer_operand->getType();
1485                 PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1486                 if (!pointer_ptr_ty)
1487                 {
1488                     if (log)
1489                         log->Printf("getPointerOperand()->getType() is not a PointerType");
1490                     err.SetErrorToGenericError();
1491                     err.SetErrorString(interpreter_internal_error);
1492                     return false;
1493                 }
1494                 Type *target_ty = pointer_ptr_ty->getElementType();
1495 
1496                 Memory::Region D = frame.ResolveValue(load_inst, llvm_module);
1497                 Memory::Region P = frame.ResolveValue(pointer_operand, llvm_module);
1498 
1499                 if (D.IsInvalid())
1500                 {
1501                     if (log)
1502                         log->Printf("LoadInst's value doesn't resolve to anything");
1503                     err.SetErrorToGenericError();
1504                     err.SetErrorString(bad_value_error);
1505                     return false;
1506                 }
1507 
1508                 if (P.IsInvalid())
1509                 {
1510                     if (log)
1511                         log->Printf("LoadInst's pointer doesn't resolve to anything");
1512                     err.SetErrorToGenericError();
1513                     err.SetErrorString(bad_value_error);
1514                     return false;
1515                 }
1516 
1517                 DataExtractorSP P_extractor(memory.GetExtractor(P));
1518                 DataEncoderSP D_encoder(memory.GetEncoder(D));
1519 
1520                 uint32_t offset = 0;
1521                 lldb::addr_t pointer = P_extractor->GetAddress(&offset);
1522 
1523                 Memory::Region R = memory.Lookup(pointer, target_ty);
1524 
1525                 if (R.IsValid())
1526                 {
1527                     if (!memory.Read(D_encoder->GetDataStart(), R.m_base, target_data.getTypeStoreSize(target_ty)))
1528                     {
1529                         if (log)
1530                             log->Printf("Couldn't read from a region on behalf of a LoadInst");
1531                         err.SetErrorToGenericError();
1532                         err.SetErrorString(memory_read_error);
1533                         return false;
1534                     }
1535                 }
1536                 else
1537                 {
1538                     if (!memory.ReadFromRawPtr(D_encoder->GetDataStart(), pointer, target_data.getTypeStoreSize(target_ty)))
1539                     {
1540                         if (log)
1541                             log->Printf("Couldn't read from a raw pointer on behalf of a LoadInst");
1542                         err.SetErrorToGenericError();
1543                         err.SetErrorString(memory_read_error);
1544                         return false;
1545                     }
1546                 }
1547 
1548                 if (log)
1549                 {
1550                     log->Printf("Interpreted a LoadInst");
1551                     log->Printf("  P : %s", frame.SummarizeValue(pointer_operand).c_str());
1552                     if (R.IsValid())
1553                         log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1554                     else
1555                         log->Printf("  R : raw pointer 0x%llx", (unsigned long long)pointer);
1556                     log->Printf("  D : %s", frame.SummarizeValue(load_inst).c_str());
1557                 }
1558             }
1559             break;
1560         case Instruction::Ret:
1561             {
1562                 if (result_name.IsEmpty())
1563                     return true;
1564 
1565                 GlobalValue *result_value = llvm_module.getNamedValue(result_name.GetCString());
1566 
1567                 if (!frame.ConstructResult(result, result_value, result_name, result_type, llvm_module))
1568                 {
1569                     if (log)
1570                         log->Printf("Couldn't construct the expression's result");
1571                     err.SetErrorToGenericError();
1572                     err.SetErrorString(bad_result_error);
1573                     return false;
1574                 }
1575 
1576                 return true;
1577             }
1578         case Instruction::Store:
1579             {
1580                 const StoreInst *store_inst = dyn_cast<StoreInst>(inst);
1581 
1582                 if (!store_inst)
1583                 {
1584                     if (log)
1585                         log->Printf("getOpcode() returns Store, but instruction is not a StoreInst");
1586                     err.SetErrorToGenericError();
1587                     err.SetErrorString(interpreter_internal_error);
1588                     return false;
1589                 }
1590 
1591                 // The semantics of Store are:
1592                 //   Resolve the region D containing the data to be stored
1593                 //   Resolve the region P containing a pointer
1594                 //   Dereference P to get the region R that the data should be stored in
1595                 //   Transfer a unit of type type(D) from D to R
1596 
1597                 const Value *value_operand = store_inst->getValueOperand();
1598                 const Value *pointer_operand = store_inst->getPointerOperand();
1599 
1600                 Type *pointer_ty = pointer_operand->getType();
1601                 PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1602                 if (!pointer_ptr_ty)
1603                     return false;
1604                 Type *target_ty = pointer_ptr_ty->getElementType();
1605 
1606                 Memory::Region D = frame.ResolveValue(value_operand, llvm_module);
1607                 Memory::Region P = frame.ResolveValue(pointer_operand, llvm_module);
1608 
1609                 if (D.IsInvalid())
1610                 {
1611                     if (log)
1612                         log->Printf("StoreInst's value doesn't resolve to anything");
1613                     err.SetErrorToGenericError();
1614                     err.SetErrorString(bad_value_error);
1615                     return false;
1616                 }
1617 
1618                 if (P.IsInvalid())
1619                 {
1620                     if (log)
1621                         log->Printf("StoreInst's pointer doesn't resolve to anything");
1622                     err.SetErrorToGenericError();
1623                     err.SetErrorString(bad_value_error);
1624                     return false;
1625                 }
1626 
1627                 DataExtractorSP P_extractor(memory.GetExtractor(P));
1628                 DataExtractorSP D_extractor(memory.GetExtractor(D));
1629 
1630                 if (!P_extractor || !D_extractor)
1631                     return false;
1632 
1633                 uint32_t offset = 0;
1634                 lldb::addr_t pointer = P_extractor->GetAddress(&offset);
1635 
1636                 Memory::Region R = memory.Lookup(pointer, target_ty);
1637 
1638                 if (R.IsValid())
1639                 {
1640                     if (!memory.Write(R.m_base, D_extractor->GetDataStart(), target_data.getTypeStoreSize(target_ty)))
1641                     {
1642                         if (log)
1643                             log->Printf("Couldn't write to a region on behalf of a LoadInst");
1644                         err.SetErrorToGenericError();
1645                         err.SetErrorString(memory_write_error);
1646                         return false;
1647                     }
1648                 }
1649                 else
1650                 {
1651                     if (!memory.WriteToRawPtr(pointer, D_extractor->GetDataStart(), target_data.getTypeStoreSize(target_ty)))
1652                     {
1653                         if (log)
1654                             log->Printf("Couldn't write to a raw pointer on behalf of a LoadInst");
1655                         err.SetErrorToGenericError();
1656                         err.SetErrorString(memory_write_error);
1657                         return false;
1658                     }
1659                 }
1660 
1661 
1662                 if (log)
1663                 {
1664                     log->Printf("Interpreted a StoreInst");
1665                     log->Printf("  D : %s", frame.SummarizeValue(value_operand).c_str());
1666                     log->Printf("  P : %s", frame.SummarizeValue(pointer_operand).c_str());
1667                     log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1668                 }
1669             }
1670             break;
1671         }
1672 
1673         ++frame.m_ii;
1674     }
1675 
1676     if (num_insts >= 4096)
1677     {
1678         err.SetErrorToGenericError();
1679         err.SetErrorString(infinite_loop_error);
1680         return false;
1681     }
1682 
1683     return false;
1684 }
1685