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 lldb::SharedPtr <lldb_private::DataEncoder>::Type DataEncoderSP;
73 typedef lldb::SharedPtr <lldb_private::DataExtractor>::Type 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 lldb::SharedPtr <Allocation>::Type  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())
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 ResolveConstant (Memory::Region &region, const Constant *constant)
542     {
543         size_t constant_size = m_target_data.getTypeStoreSize(constant->getType());
544 
545         if (const ConstantInt *constant_int = dyn_cast<ConstantInt>(constant))
546         {
547             const uint64_t *raw_data = constant_int->getValue().getRawData();
548             return m_memory.Write(region.m_base, (const uint8_t*)raw_data, constant_size);
549         }
550         else if (const ConstantFP *constant_fp = dyn_cast<ConstantFP>(constant))
551         {
552             const uint64_t *raw_data = constant_fp->getValueAPF().bitcastToAPInt().getRawData();
553             return m_memory.Write(region.m_base, (const uint8_t*)raw_data, constant_size);
554         }
555         else if (const ConstantExpr *constant_expr = dyn_cast<ConstantExpr>(constant))
556         {
557             switch (constant_expr->getOpcode())
558             {
559             default:
560                 return false;
561             case Instruction::IntToPtr:
562             case Instruction::BitCast:
563                 return ResolveConstant(region, constant_expr->getOperand(0));
564             }
565         }
566 
567         return false;
568     }
569 
570     Memory::Region ResolveValue (const Value *value, Module &module)
571     {
572         ValueMap::iterator i = m_values.find(value);
573 
574         if (i != m_values.end())
575             return i->second;
576 
577         const GlobalValue *global_value = dyn_cast<GlobalValue>(value);
578 
579         // If the variable is indirected through the argument
580         // array then we need to build an extra level of indirection
581         // for it.  This is the default; only magic arguments like
582         // "this", "self", and "_cmd" are direct.
583         bool indirect_variable = true;
584 
585         // Attempt to resolve the value using the program's data.
586         // If it is, the values to be created are:
587         //
588         // data_region - a region of memory in which the variable's data resides.
589         // ref_region - a region of memory in which its address (i.e., &var) resides.
590         //   In the JIT case, this region would be a member of the struct passed in.
591         // pointer_region - a region of memory in which the address of the pointer
592         //   resides.  This is an IR-level variable.
593         do
594         {
595             lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
596 
597             lldb_private::Value resolved_value;
598 
599             if (global_value)
600             {
601                 clang::NamedDecl *decl = IRForTarget::DeclForGlobal(global_value, &module);
602 
603                 if (!decl)
604                     break;
605 
606                 if (isa<clang::FunctionDecl>(decl))
607                 {
608                     if (log)
609                         log->Printf("The interpreter does not handle function pointers at the moment");
610 
611                     return Memory::Region();
612                 }
613 
614                 resolved_value = m_decl_map.LookupDecl(decl);
615             }
616             else
617             {
618                 // Special-case "this", "self", and "_cmd"
619 
620                 std::string name_str = value->getName().str();
621 
622                 if (name_str == "this" ||
623                     name_str == "self" ||
624                     name_str == "_cmd")
625                     resolved_value = m_decl_map.GetSpecialValue(lldb_private::ConstString(name_str.c_str()));
626 
627                 indirect_variable = false;
628             }
629 
630             if (resolved_value.GetScalar().GetType() != lldb_private::Scalar::e_void)
631             {
632                 if (resolved_value.GetContextType() == lldb_private::Value::eContextTypeRegisterInfo)
633                 {
634                     Memory::Region data_region = m_memory.Malloc(value->getType());
635                     data_region.m_allocation->m_origin = resolved_value;
636                     Memory::Region ref_region = m_memory.Malloc(value->getType());
637                     Memory::Region pointer_region;
638 
639                     if (indirect_variable)
640                         pointer_region = m_memory.Malloc(value->getType());
641 
642                     if (!Cache(data_region.m_allocation, value->getType()))
643                         return Memory::Region();
644 
645                     if (ref_region.IsInvalid())
646                         return Memory::Region();
647 
648                     if (pointer_region.IsInvalid() && indirect_variable)
649                         return Memory::Region();
650 
651                     DataEncoderSP ref_encoder = m_memory.GetEncoder(ref_region);
652 
653                     if (ref_encoder->PutAddress(0, data_region.m_base) == UINT32_MAX)
654                         return Memory::Region();
655 
656                     if (indirect_variable)
657                     {
658                         DataEncoderSP pointer_encoder = m_memory.GetEncoder(pointer_region);
659 
660                         if (pointer_encoder->PutAddress(0, ref_region.m_base) == UINT32_MAX)
661                             return Memory::Region();
662 
663                         m_values[value] = pointer_region;
664                         return pointer_region;
665                     }
666                     else
667                     {
668                         m_values[value] = ref_region;
669                         return ref_region;
670                     }
671                 }
672                 else
673                 {
674                     Memory::Region data_region = m_memory.Place(value->getType(), resolved_value.GetScalar().ULongLong(), resolved_value);
675                     Memory::Region ref_region = m_memory.Malloc(value->getType());
676                     Memory::Region pointer_region;
677 
678                     if (indirect_variable)
679                         pointer_region = m_memory.Malloc(value->getType());
680 
681                     if (ref_region.IsInvalid())
682                         return Memory::Region();
683 
684                     if (pointer_region.IsInvalid() && indirect_variable)
685                         return Memory::Region();
686 
687                     DataEncoderSP ref_encoder = m_memory.GetEncoder(ref_region);
688 
689                     if (ref_encoder->PutAddress(0, data_region.m_base) == UINT32_MAX)
690                         return Memory::Region();
691 
692                     if (indirect_variable)
693                     {
694                         DataEncoderSP pointer_encoder = m_memory.GetEncoder(pointer_region);
695 
696                         if (pointer_encoder->PutAddress(0, ref_region.m_base) == UINT32_MAX)
697                             return Memory::Region();
698 
699                         m_values[value] = pointer_region;
700                     }
701 
702                     if (log)
703                     {
704                         log->Printf("Made an allocation for %s", PrintValue(value).c_str());
705                         log->Printf("  Data contents  : %s", m_memory.PrintData(data_region.m_base, data_region.m_extent).c_str());
706                         log->Printf("  Data region    : %llx", (unsigned long long)data_region.m_base);
707                         log->Printf("  Ref region     : %llx", (unsigned long long)ref_region.m_base);
708                         if (indirect_variable)
709                             log->Printf("  Pointer region : %llx", (unsigned long long)pointer_region.m_base);
710                     }
711 
712                     if (indirect_variable)
713                         return pointer_region;
714                     else
715                         return ref_region;
716                 }
717             }
718         }
719         while(0);
720 
721         // Fall back and allocate space [allocation type Alloca]
722 
723         Type *type = value->getType();
724 
725         lldb::ValueSP backing_value(new lldb_private::Value);
726 
727         Memory::Region data_region = m_memory.Malloc(type);
728         data_region.m_allocation->m_origin.GetScalar() = (unsigned long long)data_region.m_allocation->m_data->GetBytes();
729         data_region.m_allocation->m_origin.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
730         data_region.m_allocation->m_origin.SetValueType(lldb_private::Value::eValueTypeHostAddress);
731 
732         const Constant *constant = dyn_cast<Constant>(value);
733 
734         do
735         {
736             if (!constant)
737                 break;
738 
739             if (!ResolveConstant (data_region, constant))
740                 return Memory::Region();
741         }
742         while(0);
743 
744         m_values[value] = data_region;
745         return data_region;
746     }
747 
748     bool ConstructResult (lldb::ClangExpressionVariableSP &result,
749                           const GlobalValue *result_value,
750                           const lldb_private::ConstString &result_name,
751                           lldb_private::TypeFromParser result_type,
752                           Module &module)
753     {
754         // The result_value resolves to P, a pointer to a region R containing the result data.
755         // If the result variable is a reference, the region R contains a pointer to the result R_final in the original process.
756 
757         if (!result_value)
758             return true; // There was no slot for a result – the expression doesn't return one.
759 
760         ValueMap::iterator i = m_values.find(result_value);
761 
762         if (i == m_values.end())
763             return false; // There was a slot for the result, but we didn't write into it.
764 
765         Memory::Region P = i->second;
766         DataExtractorSP P_extractor = m_memory.GetExtractor(P);
767 
768         if (!P_extractor)
769             return false;
770 
771         Type *pointer_ty = result_value->getType();
772         PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
773         if (!pointer_ptr_ty)
774             return false;
775         Type *R_ty = pointer_ptr_ty->getElementType();
776 
777         uint32_t offset = 0;
778         lldb::addr_t pointer = P_extractor->GetAddress(&offset);
779 
780         Memory::Region R = m_memory.Lookup(pointer, R_ty);
781 
782         if (R.m_allocation->m_origin.GetValueType() != lldb_private::Value::eValueTypeHostAddress ||
783             !R.m_allocation->m_data)
784             return false;
785 
786         lldb_private::Value base;
787 
788         bool transient = false;
789         bool maybe_make_load = false;
790 
791         if (m_decl_map.ResultIsReference(result_name))
792         {
793             PointerType *R_ptr_ty = dyn_cast<PointerType>(R_ty);
794             if (!R_ptr_ty)
795                 return false;
796             Type *R_final_ty = R_ptr_ty->getElementType();
797 
798             DataExtractorSP R_extractor = m_memory.GetExtractor(R);
799 
800             if (!R_extractor)
801                 return false;
802 
803             offset = 0;
804             lldb::addr_t R_pointer = R_extractor->GetAddress(&offset);
805 
806             Memory::Region R_final = m_memory.Lookup(R_pointer, R_final_ty);
807 
808             if (R_final.m_allocation)
809             {
810                 if (R_final.m_allocation->m_data)
811                     transient = true; // this is a stack allocation
812 
813                 base = R_final.m_allocation->m_origin;
814                 base.GetScalar() += (R_final.m_base - R_final.m_allocation->m_virtual_address);
815             }
816             else
817             {
818                 // We got a bare pointer.  We are going to treat it as a load address
819                 // or a file address, letting decl_map make the choice based on whether
820                 // or not a process exists.
821 
822                 base.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
823                 base.SetValueType(lldb_private::Value::eValueTypeFileAddress);
824                 base.GetScalar() = (unsigned long long)R_pointer;
825                 maybe_make_load = true;
826             }
827         }
828         else
829         {
830             base.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
831             base.SetValueType(lldb_private::Value::eValueTypeHostAddress);
832             base.GetScalar() = (unsigned long long)R.m_allocation->m_data->GetBytes() + (R.m_base - R.m_allocation->m_virtual_address);
833         }
834 
835         return m_decl_map.CompleteResultVariable (result, base, result_name, result_type, transient, maybe_make_load);
836     }
837 };
838 
839 bool
840 IRInterpreter::maybeRunOnFunction (lldb::ClangExpressionVariableSP &result,
841                                    const lldb_private::ConstString &result_name,
842                                    lldb_private::TypeFromParser result_type,
843                                    Function &llvm_function,
844                                    Module &llvm_module)
845 {
846     if (supportsFunction (llvm_function))
847         return runOnFunction(result,
848                              result_name,
849                              result_type,
850                              llvm_function,
851                              llvm_module);
852     else
853         return false;
854 }
855 
856 bool
857 IRInterpreter::supportsFunction (Function &llvm_function)
858 {
859     lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
860 
861     for (Function::iterator bbi = llvm_function.begin(), bbe = llvm_function.end();
862          bbi != bbe;
863          ++bbi)
864     {
865         for (BasicBlock::iterator ii = bbi->begin(), ie = bbi->end();
866              ii != ie;
867              ++ii)
868         {
869             switch (ii->getOpcode())
870             {
871             default:
872                 {
873                     if (log)
874                         log->Printf("Unsupported instruction: %s", PrintValue(ii).c_str());
875                     return false;
876                 }
877             case Instruction::Add:
878             case Instruction::Alloca:
879             case Instruction::BitCast:
880             case Instruction::Br:
881             case Instruction::GetElementPtr:
882                 break;
883             case Instruction::ICmp:
884                 {
885                     ICmpInst *icmp_inst = dyn_cast<ICmpInst>(ii);
886 
887                     if (!icmp_inst)
888                         return false;
889 
890                     switch (icmp_inst->getPredicate())
891                     {
892                     default:
893                         {
894                             if (log)
895                                 log->Printf("Unsupported ICmp predicate: %s", PrintValue(ii).c_str());
896                             return false;
897                         }
898                     case CmpInst::ICMP_EQ:
899                     case CmpInst::ICMP_NE:
900                     case CmpInst::ICMP_UGT:
901                     case CmpInst::ICMP_UGE:
902                     case CmpInst::ICMP_ULT:
903                     case CmpInst::ICMP_ULE:
904                     case CmpInst::ICMP_SGT:
905                     case CmpInst::ICMP_SGE:
906                     case CmpInst::ICMP_SLT:
907                     case CmpInst::ICMP_SLE:
908                         break;
909                     }
910                 }
911                 break;
912             case Instruction::IntToPtr:
913             case Instruction::Load:
914             case Instruction::Mul:
915             case Instruction::Ret:
916             case Instruction::SDiv:
917             case Instruction::Store:
918             case Instruction::Sub:
919             case Instruction::UDiv:
920                 break;
921             }
922         }
923     }
924 
925     return true;
926 }
927 
928 bool
929 IRInterpreter::runOnFunction (lldb::ClangExpressionVariableSP &result,
930                               const lldb_private::ConstString &result_name,
931                               lldb_private::TypeFromParser result_type,
932                               Function &llvm_function,
933                               Module &llvm_module)
934 {
935     lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
936 
937     lldb_private::ClangExpressionDeclMap::TargetInfo target_info = m_decl_map.GetTargetInfo();
938 
939     if (!target_info.IsValid())
940         return false;
941 
942     lldb::addr_t alloc_min;
943     lldb::addr_t alloc_max;
944 
945     switch (target_info.address_byte_size)
946     {
947     default:
948         return false;
949     case 4:
950         alloc_min = 0x00001000llu;
951         alloc_max = 0x0000ffffllu;
952         break;
953     case 8:
954         alloc_min = 0x0000000000001000llu;
955         alloc_max = 0x000000000000ffffllu;
956         break;
957     }
958 
959     TargetData target_data(&llvm_module);
960     if (target_data.getPointerSize() != target_info.address_byte_size)
961         return false;
962     if (target_data.isLittleEndian() != (target_info.byte_order == lldb::eByteOrderLittle))
963         return false;
964 
965     Memory memory(target_data, m_decl_map, alloc_min, alloc_max);
966     InterpreterStackFrame frame(target_data, memory, m_decl_map);
967 
968     uint32_t num_insts = 0;
969 
970     frame.Jump(llvm_function.begin());
971 
972     while (frame.m_ii != frame.m_ie && (++num_insts < 4096))
973     {
974         const Instruction *inst = frame.m_ii;
975 
976         if (log)
977             log->Printf("Interpreting %s", PrintValue(inst).c_str());
978 
979         switch (inst->getOpcode())
980         {
981         default:
982             break;
983         case Instruction::Add:
984         case Instruction::Sub:
985         case Instruction::Mul:
986         case Instruction::SDiv:
987         case Instruction::UDiv:
988             {
989                 const BinaryOperator *bin_op = dyn_cast<BinaryOperator>(inst);
990 
991                 if (!bin_op)
992                 {
993                     if (log)
994                         log->Printf("getOpcode() returns %s, but instruction is not a BinaryOperator", inst->getOpcodeName());
995 
996                     return false;
997                 }
998 
999                 Value *lhs = inst->getOperand(0);
1000                 Value *rhs = inst->getOperand(1);
1001 
1002                 lldb_private::Scalar L;
1003                 lldb_private::Scalar R;
1004 
1005                 if (!frame.EvaluateValue(L, lhs, llvm_module))
1006                 {
1007                     if (log)
1008                         log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
1009 
1010                     return false;
1011                 }
1012 
1013                 if (!frame.EvaluateValue(R, rhs, llvm_module))
1014                 {
1015                     if (log)
1016                         log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
1017 
1018                     return false;
1019                 }
1020 
1021                 lldb_private::Scalar result;
1022 
1023                 switch (inst->getOpcode())
1024                 {
1025                 default:
1026                     break;
1027                 case Instruction::Add:
1028                     result = L + R;
1029                     break;
1030                 case Instruction::Mul:
1031                     result = L * R;
1032                     break;
1033                 case Instruction::Sub:
1034                     result = L - R;
1035                     break;
1036                 case Instruction::SDiv:
1037                     result = L / R;
1038                     break;
1039                 case Instruction::UDiv:
1040                     result = L.GetRawBits64(0) / R.GetRawBits64(1);
1041                     break;
1042                 }
1043 
1044                 frame.AssignValue(inst, result, llvm_module);
1045 
1046                 if (log)
1047                 {
1048                     log->Printf("Interpreted a %s", inst->getOpcodeName());
1049                     log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
1050                     log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
1051                     log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
1052                 }
1053             }
1054             break;
1055         case Instruction::Alloca:
1056             {
1057                 const AllocaInst *alloca_inst = dyn_cast<AllocaInst>(inst);
1058 
1059                 if (!alloca_inst)
1060                 {
1061                     if (log)
1062                         log->Printf("getOpcode() returns Alloca, but instruction is not an AllocaInst");
1063 
1064                     return false;
1065                 }
1066 
1067                 if (alloca_inst->isArrayAllocation())
1068                 {
1069                     if (log)
1070                         log->Printf("AllocaInsts are not handled if isArrayAllocation() is true");
1071 
1072                     return false;
1073                 }
1074 
1075                 // The semantics of Alloca are:
1076                 //   Create a region R of virtual memory of type T, backed by a data buffer
1077                 //   Create a region P of virtual memory of type T*, backed by a data buffer
1078                 //   Write the virtual address of R into P
1079 
1080                 Type *T = alloca_inst->getAllocatedType();
1081                 Type *Tptr = alloca_inst->getType();
1082 
1083                 Memory::Region R = memory.Malloc(T);
1084 
1085                 if (R.IsInvalid())
1086                 {
1087                     if (log)
1088                         log->Printf("Couldn't allocate memory for an AllocaInst");
1089 
1090                     return false;
1091                 }
1092 
1093                 Memory::Region P = memory.Malloc(Tptr);
1094 
1095                 if (P.IsInvalid())
1096                 {
1097                     if (log)
1098                         log->Printf("Couldn't allocate the result pointer for an AllocaInst");
1099 
1100                     return false;
1101                 }
1102 
1103                 DataEncoderSP P_encoder = memory.GetEncoder(P);
1104 
1105                 if (P_encoder->PutAddress(0, R.m_base) == UINT32_MAX)
1106                 {
1107                     if (log)
1108                         log->Printf("Couldn't write the reseult pointer for an AllocaInst");
1109 
1110                     return false;
1111                 }
1112 
1113                 frame.m_values[alloca_inst] = P;
1114 
1115                 if (log)
1116                 {
1117                     log->Printf("Interpreted an AllocaInst");
1118                     log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1119                     log->Printf("  P : %s", frame.SummarizeValue(alloca_inst).c_str());
1120                 }
1121             }
1122             break;
1123         case Instruction::BitCast:
1124             {
1125                 const BitCastInst *bit_cast_inst = dyn_cast<BitCastInst>(inst);
1126 
1127                 if (!bit_cast_inst)
1128                 {
1129                     if (log)
1130                         log->Printf("getOpcode() returns BitCast, but instruction is not a BitCastInst");
1131 
1132                     return false;
1133                 }
1134 
1135                 Value *source = bit_cast_inst->getOperand(0);
1136 
1137                 lldb_private::Scalar S;
1138 
1139                 if (!frame.EvaluateValue(S, source, llvm_module))
1140                 {
1141                     if (log)
1142                         log->Printf("Couldn't evaluate %s", PrintValue(source).c_str());
1143 
1144                     return false;
1145                 }
1146 
1147                 frame.AssignValue(inst, S, llvm_module);
1148             }
1149             break;
1150         case Instruction::Br:
1151             {
1152                 const BranchInst *br_inst = dyn_cast<BranchInst>(inst);
1153 
1154                 if (!br_inst)
1155                 {
1156                     if (log)
1157                         log->Printf("getOpcode() returns Br, but instruction is not a BranchInst");
1158 
1159                     return false;
1160                 }
1161 
1162                 if (br_inst->isConditional())
1163                 {
1164                     Value *condition = br_inst->getCondition();
1165 
1166                     lldb_private::Scalar C;
1167 
1168                     if (!frame.EvaluateValue(C, condition, llvm_module))
1169                     {
1170                         if (log)
1171                             log->Printf("Couldn't evaluate %s", PrintValue(condition).c_str());
1172 
1173                         return false;
1174                     }
1175 
1176                     if (C.GetRawBits64(0))
1177                         frame.Jump(br_inst->getSuccessor(0));
1178                     else
1179                         frame.Jump(br_inst->getSuccessor(1));
1180 
1181                     if (log)
1182                     {
1183                         log->Printf("Interpreted a BrInst with a condition");
1184                         log->Printf("  cond : %s", frame.SummarizeValue(condition).c_str());
1185                     }
1186                 }
1187                 else
1188                 {
1189                     frame.Jump(br_inst->getSuccessor(0));
1190 
1191                     if (log)
1192                     {
1193                         log->Printf("Interpreted a BrInst with no condition");
1194                     }
1195                 }
1196             }
1197             continue;
1198         case Instruction::GetElementPtr:
1199             {
1200                 const GetElementPtrInst *gep_inst = dyn_cast<GetElementPtrInst>(inst);
1201 
1202                 if (!gep_inst)
1203                 {
1204                     if (log)
1205                         log->Printf("getOpcode() returns GetElementPtr, but instruction is not a GetElementPtrInst");
1206 
1207                     return false;
1208                 }
1209 
1210                 const Value *pointer_operand = gep_inst->getPointerOperand();
1211                 Type *pointer_type = pointer_operand->getType();
1212 
1213                 lldb_private::Scalar P;
1214 
1215                 if (!frame.EvaluateValue(P, pointer_operand, llvm_module))
1216                     return false;
1217 
1218                 SmallVector <Value *, 8> indices (gep_inst->idx_begin(),
1219                                                   gep_inst->idx_end());
1220 
1221                 uint64_t offset = target_data.getIndexedOffset(pointer_type, indices);
1222 
1223                 lldb_private::Scalar Poffset = P + offset;
1224 
1225                 frame.AssignValue(inst, Poffset, llvm_module);
1226 
1227                 if (log)
1228                 {
1229                     log->Printf("Interpreted a GetElementPtrInst");
1230                     log->Printf("  P       : %s", frame.SummarizeValue(pointer_operand).c_str());
1231                     log->Printf("  Poffset : %s", frame.SummarizeValue(inst).c_str());
1232                 }
1233             }
1234             break;
1235         case Instruction::ICmp:
1236             {
1237                 const ICmpInst *icmp_inst = dyn_cast<ICmpInst>(inst);
1238 
1239                 if (!icmp_inst)
1240                 {
1241                     if (log)
1242                         log->Printf("getOpcode() returns ICmp, but instruction is not an ICmpInst");
1243 
1244                     return false;
1245                 }
1246 
1247                 CmpInst::Predicate predicate = icmp_inst->getPredicate();
1248 
1249                 Value *lhs = inst->getOperand(0);
1250                 Value *rhs = inst->getOperand(1);
1251 
1252                 lldb_private::Scalar L;
1253                 lldb_private::Scalar R;
1254 
1255                 if (!frame.EvaluateValue(L, lhs, llvm_module))
1256                 {
1257                     if (log)
1258                         log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
1259 
1260                     return false;
1261                 }
1262 
1263                 if (!frame.EvaluateValue(R, rhs, llvm_module))
1264                 {
1265                     if (log)
1266                         log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
1267 
1268                     return false;
1269                 }
1270 
1271                 lldb_private::Scalar result;
1272 
1273                 switch (predicate)
1274                 {
1275                 default:
1276                     return false;
1277                 case CmpInst::ICMP_EQ:
1278                     result = (L == R);
1279                     break;
1280                 case CmpInst::ICMP_NE:
1281                     result = (L != R);
1282                     break;
1283                 case CmpInst::ICMP_UGT:
1284                     result = (L.GetRawBits64(0) > R.GetRawBits64(0));
1285                     break;
1286                 case CmpInst::ICMP_UGE:
1287                     result = (L.GetRawBits64(0) >= R.GetRawBits64(0));
1288                     break;
1289                 case CmpInst::ICMP_ULT:
1290                     result = (L.GetRawBits64(0) < R.GetRawBits64(0));
1291                     break;
1292                 case CmpInst::ICMP_ULE:
1293                     result = (L.GetRawBits64(0) <= R.GetRawBits64(0));
1294                     break;
1295                 case CmpInst::ICMP_SGT:
1296                     result = (L > R);
1297                     break;
1298                 case CmpInst::ICMP_SGE:
1299                     result = (L >= R);
1300                     break;
1301                 case CmpInst::ICMP_SLT:
1302                     result = (L < R);
1303                     break;
1304                 case CmpInst::ICMP_SLE:
1305                     result = (L <= R);
1306                     break;
1307                 }
1308 
1309                 frame.AssignValue(inst, result, llvm_module);
1310 
1311                 if (log)
1312                 {
1313                     log->Printf("Interpreted an ICmpInst");
1314                     log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
1315                     log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
1316                     log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
1317                 }
1318             }
1319             break;
1320         case Instruction::IntToPtr:
1321             {
1322                 const IntToPtrInst *int_to_ptr_inst = dyn_cast<IntToPtrInst>(inst);
1323 
1324                 if (!int_to_ptr_inst)
1325                 {
1326                     if (log)
1327                         log->Printf("getOpcode() returns IntToPtr, but instruction is not an IntToPtrInst");
1328 
1329                     return false;
1330                 }
1331 
1332                 Value *src_operand = int_to_ptr_inst->getOperand(0);
1333 
1334                 lldb_private::Scalar I;
1335 
1336                 if (!frame.EvaluateValue(I, src_operand, llvm_module))
1337                     return false;
1338 
1339                 frame.AssignValue(inst, I, llvm_module);
1340 
1341                 if (log)
1342                 {
1343                     log->Printf("Interpreted an IntToPtr");
1344                     log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1345                     log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1346                 }
1347             }
1348             break;
1349         case Instruction::Load:
1350             {
1351                 const LoadInst *load_inst = dyn_cast<LoadInst>(inst);
1352 
1353                 if (!load_inst)
1354                 {
1355                     if (log)
1356                         log->Printf("getOpcode() returns Load, but instruction is not a LoadInst");
1357 
1358                     return false;
1359                 }
1360 
1361                 // The semantics of Load are:
1362                 //   Create a region D that will contain the loaded data
1363                 //   Resolve the region P containing a pointer
1364                 //   Dereference P to get the region R that the data should be loaded from
1365                 //   Transfer a unit of type type(D) from R to D
1366 
1367                 const Value *pointer_operand = load_inst->getPointerOperand();
1368 
1369                 Type *pointer_ty = pointer_operand->getType();
1370                 PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1371                 if (!pointer_ptr_ty)
1372                     return false;
1373                 Type *target_ty = pointer_ptr_ty->getElementType();
1374 
1375                 Memory::Region D = frame.ResolveValue(load_inst, llvm_module);
1376                 Memory::Region P = frame.ResolveValue(pointer_operand, llvm_module);
1377 
1378                 if (D.IsInvalid())
1379                 {
1380                     if (log)
1381                         log->Printf("LoadInst's value doesn't resolve to anything");
1382 
1383                     return false;
1384                 }
1385 
1386                 if (P.IsInvalid())
1387                 {
1388                     if (log)
1389                         log->Printf("LoadInst's pointer doesn't resolve to anything");
1390 
1391                     return false;
1392                 }
1393 
1394                 DataExtractorSP P_extractor(memory.GetExtractor(P));
1395                 DataEncoderSP D_encoder(memory.GetEncoder(D));
1396 
1397                 uint32_t offset = 0;
1398                 lldb::addr_t pointer = P_extractor->GetAddress(&offset);
1399 
1400                 Memory::Region R = memory.Lookup(pointer, target_ty);
1401 
1402                 if (R.IsValid())
1403                 {
1404                     if (!memory.Read(D_encoder->GetDataStart(), R.m_base, target_data.getTypeStoreSize(target_ty)))
1405                     {
1406                         if (log)
1407                             log->Printf("Couldn't read from a region on behalf of a LoadInst");
1408 
1409                         return false;
1410                     }
1411                 }
1412                 else
1413                 {
1414                     if (!memory.ReadFromRawPtr(D_encoder->GetDataStart(), pointer, target_data.getTypeStoreSize(target_ty)))
1415                     {
1416                         if (log)
1417                             log->Printf("Couldn't read from a raw pointer on behalf of a LoadInst");
1418 
1419                         return false;
1420                     }
1421                 }
1422 
1423                 if (log)
1424                 {
1425                     log->Printf("Interpreted a LoadInst");
1426                     log->Printf("  P : %s", frame.SummarizeValue(pointer_operand).c_str());
1427                     if (R.IsValid())
1428                         log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1429                     else
1430                         log->Printf("  R : raw pointer 0x%llx", (unsigned long long)pointer);
1431                     log->Printf("  D : %s", frame.SummarizeValue(load_inst).c_str());
1432                 }
1433             }
1434             break;
1435         case Instruction::Ret:
1436             {
1437                 if (result_name.IsEmpty())
1438                     return true;
1439 
1440                 GlobalValue *result_value = llvm_module.getNamedValue(result_name.GetCString());
1441                 return frame.ConstructResult(result, result_value, result_name, result_type, llvm_module);
1442             }
1443         case Instruction::Store:
1444             {
1445                 const StoreInst *store_inst = dyn_cast<StoreInst>(inst);
1446 
1447                 if (!store_inst)
1448                 {
1449                     if (log)
1450                         log->Printf("getOpcode() returns Store, but instruction is not a StoreInst");
1451 
1452                     return false;
1453                 }
1454 
1455                 // The semantics of Store are:
1456                 //   Resolve the region D containing the data to be stored
1457                 //   Resolve the region P containing a pointer
1458                 //   Dereference P to get the region R that the data should be stored in
1459                 //   Transfer a unit of type type(D) from D to R
1460 
1461                 const Value *value_operand = store_inst->getValueOperand();
1462                 const Value *pointer_operand = store_inst->getPointerOperand();
1463 
1464                 Type *pointer_ty = pointer_operand->getType();
1465                 PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1466                 if (!pointer_ptr_ty)
1467                     return false;
1468                 Type *target_ty = pointer_ptr_ty->getElementType();
1469 
1470                 Memory::Region D = frame.ResolveValue(value_operand, llvm_module);
1471                 Memory::Region P = frame.ResolveValue(pointer_operand, llvm_module);
1472 
1473                 if (D.IsInvalid())
1474                 {
1475                     if (log)
1476                         log->Printf("StoreInst's value doesn't resolve to anything");
1477 
1478                     return false;
1479                 }
1480 
1481                 if (P.IsInvalid())
1482                 {
1483                     if (log)
1484                         log->Printf("StoreInst's pointer doesn't resolve to anything");
1485 
1486                     return false;
1487                 }
1488 
1489                 DataExtractorSP P_extractor(memory.GetExtractor(P));
1490                 DataExtractorSP D_extractor(memory.GetExtractor(D));
1491 
1492                 if (!P_extractor || !D_extractor)
1493                     return false;
1494 
1495                 uint32_t offset = 0;
1496                 lldb::addr_t pointer = P_extractor->GetAddress(&offset);
1497 
1498                 Memory::Region R = memory.Lookup(pointer, target_ty);
1499 
1500                 if (R.IsValid())
1501                 {
1502                     if (!memory.Write(R.m_base, D_extractor->GetDataStart(), target_data.getTypeStoreSize(target_ty)))
1503                     {
1504                         if (log)
1505                             log->Printf("Couldn't write to a region on behalf of a LoadInst");
1506 
1507                         return false;
1508                     }
1509                 }
1510                 else
1511                 {
1512                     if (!memory.WriteToRawPtr(pointer, D_extractor->GetDataStart(), target_data.getTypeStoreSize(target_ty)))
1513                     {
1514                         if (log)
1515                             log->Printf("Couldn't write to a raw pointer on behalf of a LoadInst");
1516 
1517                         return false;
1518                     }
1519                 }
1520 
1521 
1522                 if (log)
1523                 {
1524                     log->Printf("Interpreted a StoreInst");
1525                     log->Printf("  D : %s", frame.SummarizeValue(value_operand).c_str());
1526                     log->Printf("  P : %s", frame.SummarizeValue(pointer_operand).c_str());
1527                     log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1528                 }
1529             }
1530             break;
1531         }
1532 
1533         ++frame.m_ii;
1534     }
1535 
1536     if (num_insts >= 4096)
1537         return false;
1538 
1539     return false;
1540 }
1541