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 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 (log)
657                     {
658                         log->Printf("Made an allocation for register variable %s", PrintValue(value).c_str());
659                         log->Printf("  Data contents  : %s", m_memory.PrintData(data_region.m_base, data_region.m_extent).c_str());
660                         log->Printf("  Data region    : %llx", (unsigned long long)data_region.m_base);
661                         log->Printf("  Ref region     : %llx", (unsigned long long)ref_region.m_base);
662                         if (indirect_variable)
663                             log->Printf("  Pointer region : %llx", (unsigned long long)pointer_region.m_base);
664                     }
665 
666                     if (indirect_variable)
667                     {
668                         DataEncoderSP pointer_encoder = m_memory.GetEncoder(pointer_region);
669 
670                         if (pointer_encoder->PutAddress(0, ref_region.m_base) == UINT32_MAX)
671                             return Memory::Region();
672 
673                         m_values[value] = pointer_region;
674                         return pointer_region;
675                     }
676                     else
677                     {
678                         m_values[value] = ref_region;
679                         return ref_region;
680                     }
681                 }
682                 else
683                 {
684                     Memory::Region data_region = m_memory.Place(value->getType(), resolved_value.GetScalar().ULongLong(), resolved_value);
685                     Memory::Region ref_region = m_memory.Malloc(value->getType());
686                     Memory::Region pointer_region;
687 
688                     if (indirect_variable)
689                         pointer_region = m_memory.Malloc(value->getType());
690 
691                     if (ref_region.IsInvalid())
692                         return Memory::Region();
693 
694                     if (pointer_region.IsInvalid() && indirect_variable)
695                         return Memory::Region();
696 
697                     DataEncoderSP ref_encoder = m_memory.GetEncoder(ref_region);
698 
699                     if (ref_encoder->PutAddress(0, data_region.m_base) == UINT32_MAX)
700                         return Memory::Region();
701 
702                     if (indirect_variable)
703                     {
704                         DataEncoderSP pointer_encoder = m_memory.GetEncoder(pointer_region);
705 
706                         if (pointer_encoder->PutAddress(0, ref_region.m_base) == UINT32_MAX)
707                             return Memory::Region();
708 
709                         m_values[value] = pointer_region;
710                     }
711 
712                     if (log)
713                     {
714                         log->Printf("Made an allocation for %s", PrintValue(value).c_str());
715                         log->Printf("  Data contents  : %s", m_memory.PrintData(data_region.m_base, data_region.m_extent).c_str());
716                         log->Printf("  Data region    : %llx", (unsigned long long)data_region.m_base);
717                         log->Printf("  Ref region     : %llx", (unsigned long long)ref_region.m_base);
718                         if (indirect_variable)
719                             log->Printf("  Pointer region : %llx", (unsigned long long)pointer_region.m_base);
720                     }
721 
722                     if (indirect_variable)
723                         return pointer_region;
724                     else
725                         return ref_region;
726                 }
727             }
728         }
729         while(0);
730 
731         // Fall back and allocate space [allocation type Alloca]
732 
733         Type *type = value->getType();
734 
735         lldb::ValueSP backing_value(new lldb_private::Value);
736 
737         Memory::Region data_region = m_memory.Malloc(type);
738         data_region.m_allocation->m_origin.GetScalar() = (unsigned long long)data_region.m_allocation->m_data->GetBytes();
739         data_region.m_allocation->m_origin.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
740         data_region.m_allocation->m_origin.SetValueType(lldb_private::Value::eValueTypeHostAddress);
741 
742         const Constant *constant = dyn_cast<Constant>(value);
743 
744         do
745         {
746             if (!constant)
747                 break;
748 
749             if (!ResolveConstant (data_region, constant))
750                 return Memory::Region();
751         }
752         while(0);
753 
754         m_values[value] = data_region;
755         return data_region;
756     }
757 
758     bool ConstructResult (lldb::ClangExpressionVariableSP &result,
759                           const GlobalValue *result_value,
760                           const lldb_private::ConstString &result_name,
761                           lldb_private::TypeFromParser result_type,
762                           Module &module)
763     {
764         // The result_value resolves to P, a pointer to a region R containing the result data.
765         // If the result variable is a reference, the region R contains a pointer to the result R_final in the original process.
766 
767         if (!result_value)
768             return true; // There was no slot for a result – the expression doesn't return one.
769 
770         ValueMap::iterator i = m_values.find(result_value);
771 
772         if (i == m_values.end())
773             return false; // There was a slot for the result, but we didn't write into it.
774 
775         Memory::Region P = i->second;
776         DataExtractorSP P_extractor = m_memory.GetExtractor(P);
777 
778         if (!P_extractor)
779             return false;
780 
781         Type *pointer_ty = result_value->getType();
782         PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
783         if (!pointer_ptr_ty)
784             return false;
785         Type *R_ty = pointer_ptr_ty->getElementType();
786 
787         uint32_t offset = 0;
788         lldb::addr_t pointer = P_extractor->GetAddress(&offset);
789 
790         Memory::Region R = m_memory.Lookup(pointer, R_ty);
791 
792         if (R.m_allocation->m_origin.GetValueType() != lldb_private::Value::eValueTypeHostAddress ||
793             !R.m_allocation->m_data)
794             return false;
795 
796         lldb_private::Value base;
797 
798         bool transient = false;
799         bool maybe_make_load = false;
800 
801         if (m_decl_map.ResultIsReference(result_name))
802         {
803             PointerType *R_ptr_ty = dyn_cast<PointerType>(R_ty);
804             if (!R_ptr_ty)
805                 return false;
806             Type *R_final_ty = R_ptr_ty->getElementType();
807 
808             DataExtractorSP R_extractor = m_memory.GetExtractor(R);
809 
810             if (!R_extractor)
811                 return false;
812 
813             offset = 0;
814             lldb::addr_t R_pointer = R_extractor->GetAddress(&offset);
815 
816             Memory::Region R_final = m_memory.Lookup(R_pointer, R_final_ty);
817 
818             if (R_final.m_allocation)
819             {
820                 if (R_final.m_allocation->m_data)
821                     transient = true; // this is a stack allocation
822 
823                 base = R_final.m_allocation->m_origin;
824                 base.GetScalar() += (R_final.m_base - R_final.m_allocation->m_virtual_address);
825             }
826             else
827             {
828                 // We got a bare pointer.  We are going to treat it as a load address
829                 // or a file address, letting decl_map make the choice based on whether
830                 // or not a process exists.
831 
832                 base.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
833                 base.SetValueType(lldb_private::Value::eValueTypeFileAddress);
834                 base.GetScalar() = (unsigned long long)R_pointer;
835                 maybe_make_load = true;
836             }
837         }
838         else
839         {
840             base.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
841             base.SetValueType(lldb_private::Value::eValueTypeHostAddress);
842             base.GetScalar() = (unsigned long long)R.m_allocation->m_data->GetBytes() + (R.m_base - R.m_allocation->m_virtual_address);
843         }
844 
845         return m_decl_map.CompleteResultVariable (result, base, result_name, result_type, transient, maybe_make_load);
846     }
847 };
848 
849 bool
850 IRInterpreter::maybeRunOnFunction (lldb::ClangExpressionVariableSP &result,
851                                    const lldb_private::ConstString &result_name,
852                                    lldb_private::TypeFromParser result_type,
853                                    Function &llvm_function,
854                                    Module &llvm_module,
855                                    lldb_private::Error &err)
856 {
857     if (supportsFunction (llvm_function, err))
858         return runOnFunction(result,
859                              result_name,
860                              result_type,
861                              llvm_function,
862                              llvm_module,
863                              err);
864     else
865         return false;
866 }
867 
868 static const char *unsupported_opcode_error         = "Interpreter doesn't handle one of the expression's opcodes";
869 static const char *interpreter_initialization_error = "Interpreter couldn't be initialized";
870 static const char *interpreter_internal_error       = "Interpreter encountered an internal error";
871 static const char *bad_value_error                  = "Interpreter couldn't resolve a value during execution";
872 static const char *memory_allocation_error          = "Interpreter couldn't allocate memory";
873 static const char *memory_write_error               = "Interpreter couldn't write to memory";
874 static const char *memory_read_error                = "Interpreter couldn't read from memory";
875 static const char *infinite_loop_error              = "Interpreter ran for too many cycles";
876 
877 bool
878 IRInterpreter::supportsFunction (Function &llvm_function,
879                                  lldb_private::Error &err)
880 {
881     lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
882 
883     for (Function::iterator bbi = llvm_function.begin(), bbe = llvm_function.end();
884          bbi != bbe;
885          ++bbi)
886     {
887         for (BasicBlock::iterator ii = bbi->begin(), ie = bbi->end();
888              ii != ie;
889              ++ii)
890         {
891             switch (ii->getOpcode())
892             {
893             default:
894                 {
895                     if (log)
896                         log->Printf("Unsupported instruction: %s", PrintValue(ii).c_str());
897                     err.SetErrorToGenericError();
898                     err.SetErrorString(unsupported_opcode_error);
899                     return false;
900                 }
901             case Instruction::Add:
902             case Instruction::Alloca:
903             case Instruction::BitCast:
904             case Instruction::Br:
905             case Instruction::GetElementPtr:
906                 break;
907             case Instruction::ICmp:
908                 {
909                     ICmpInst *icmp_inst = dyn_cast<ICmpInst>(ii);
910 
911                     if (!icmp_inst)
912                     {
913                         err.SetErrorToGenericError();
914                         err.SetErrorString(interpreter_internal_error);
915                         return false;
916                     }
917 
918                     switch (icmp_inst->getPredicate())
919                     {
920                     default:
921                         {
922                             if (log)
923                                 log->Printf("Unsupported ICmp predicate: %s", PrintValue(ii).c_str());
924 
925                             err.SetErrorToGenericError();
926                             err.SetErrorString(unsupported_opcode_error);
927                             return false;
928                         }
929                     case CmpInst::ICMP_EQ:
930                     case CmpInst::ICMP_NE:
931                     case CmpInst::ICMP_UGT:
932                     case CmpInst::ICMP_UGE:
933                     case CmpInst::ICMP_ULT:
934                     case CmpInst::ICMP_ULE:
935                     case CmpInst::ICMP_SGT:
936                     case CmpInst::ICMP_SGE:
937                     case CmpInst::ICMP_SLT:
938                     case CmpInst::ICMP_SLE:
939                         break;
940                     }
941                 }
942                 break;
943             case Instruction::IntToPtr:
944             case Instruction::Load:
945             case Instruction::Mul:
946             case Instruction::Ret:
947             case Instruction::SDiv:
948             case Instruction::Store:
949             case Instruction::Sub:
950             case Instruction::UDiv:
951                 break;
952             }
953         }
954     }
955 
956     return true;
957 }
958 
959 bool
960 IRInterpreter::runOnFunction (lldb::ClangExpressionVariableSP &result,
961                               const lldb_private::ConstString &result_name,
962                               lldb_private::TypeFromParser result_type,
963                               Function &llvm_function,
964                               Module &llvm_module,
965                               lldb_private::Error &err)
966 {
967     lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
968 
969     lldb_private::ClangExpressionDeclMap::TargetInfo target_info = m_decl_map.GetTargetInfo();
970 
971     if (!target_info.IsValid())
972     {
973         err.SetErrorToGenericError();
974         err.SetErrorString(interpreter_initialization_error);
975         return false;
976     }
977 
978     lldb::addr_t alloc_min;
979     lldb::addr_t alloc_max;
980 
981     switch (target_info.address_byte_size)
982     {
983     default:
984         err.SetErrorToGenericError();
985         err.SetErrorString(interpreter_initialization_error);
986         return false;
987     case 4:
988         alloc_min = 0x00001000llu;
989         alloc_max = 0x0000ffffllu;
990         break;
991     case 8:
992         alloc_min = 0x0000000000001000llu;
993         alloc_max = 0x000000000000ffffllu;
994         break;
995     }
996 
997     TargetData target_data(&llvm_module);
998     if (target_data.getPointerSize() != target_info.address_byte_size)
999     {
1000         err.SetErrorToGenericError();
1001         err.SetErrorString(interpreter_initialization_error);
1002         return false;
1003     }
1004     if (target_data.isLittleEndian() != (target_info.byte_order == lldb::eByteOrderLittle))
1005     {
1006         err.SetErrorToGenericError();
1007         err.SetErrorString(interpreter_initialization_error);
1008         return false;
1009     }
1010 
1011     Memory memory(target_data, m_decl_map, alloc_min, alloc_max);
1012     InterpreterStackFrame frame(target_data, memory, m_decl_map);
1013 
1014     uint32_t num_insts = 0;
1015 
1016     frame.Jump(llvm_function.begin());
1017 
1018     while (frame.m_ii != frame.m_ie && (++num_insts < 4096))
1019     {
1020         const Instruction *inst = frame.m_ii;
1021 
1022         if (log)
1023             log->Printf("Interpreting %s", PrintValue(inst).c_str());
1024 
1025         switch (inst->getOpcode())
1026         {
1027         default:
1028             break;
1029         case Instruction::Add:
1030         case Instruction::Sub:
1031         case Instruction::Mul:
1032         case Instruction::SDiv:
1033         case Instruction::UDiv:
1034             {
1035                 const BinaryOperator *bin_op = dyn_cast<BinaryOperator>(inst);
1036 
1037                 if (!bin_op)
1038                 {
1039                     if (log)
1040                         log->Printf("getOpcode() returns %s, but instruction is not a BinaryOperator", inst->getOpcodeName());
1041                     err.SetErrorToGenericError();
1042                     err.SetErrorString(interpreter_internal_error);
1043                     return false;
1044                 }
1045 
1046                 Value *lhs = inst->getOperand(0);
1047                 Value *rhs = inst->getOperand(1);
1048 
1049                 lldb_private::Scalar L;
1050                 lldb_private::Scalar R;
1051 
1052                 if (!frame.EvaluateValue(L, lhs, llvm_module))
1053                 {
1054                     if (log)
1055                         log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
1056                     err.SetErrorToGenericError();
1057                     err.SetErrorString(bad_value_error);
1058                     return false;
1059                 }
1060 
1061                 if (!frame.EvaluateValue(R, rhs, llvm_module))
1062                 {
1063                     if (log)
1064                         log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
1065                     err.SetErrorToGenericError();
1066                     err.SetErrorString(bad_value_error);
1067                     return false;
1068                 }
1069 
1070                 lldb_private::Scalar result;
1071 
1072                 switch (inst->getOpcode())
1073                 {
1074                 default:
1075                     break;
1076                 case Instruction::Add:
1077                     result = L + R;
1078                     break;
1079                 case Instruction::Mul:
1080                     result = L * R;
1081                     break;
1082                 case Instruction::Sub:
1083                     result = L - R;
1084                     break;
1085                 case Instruction::SDiv:
1086                     result = L / R;
1087                     break;
1088                 case Instruction::UDiv:
1089                     result = L.GetRawBits64(0) / R.GetRawBits64(1);
1090                     break;
1091                 }
1092 
1093                 frame.AssignValue(inst, result, llvm_module);
1094 
1095                 if (log)
1096                 {
1097                     log->Printf("Interpreted a %s", inst->getOpcodeName());
1098                     log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
1099                     log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
1100                     log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
1101                 }
1102             }
1103             break;
1104         case Instruction::Alloca:
1105             {
1106                 const AllocaInst *alloca_inst = dyn_cast<AllocaInst>(inst);
1107 
1108                 if (!alloca_inst)
1109                 {
1110                     if (log)
1111                         log->Printf("getOpcode() returns Alloca, but instruction is not an AllocaInst");
1112                     err.SetErrorToGenericError();
1113                     err.SetErrorString(interpreter_internal_error);
1114                     return false;
1115                 }
1116 
1117                 if (alloca_inst->isArrayAllocation())
1118                 {
1119                     if (log)
1120                         log->Printf("AllocaInsts are not handled if isArrayAllocation() is true");
1121                     err.SetErrorToGenericError();
1122                     err.SetErrorString(unsupported_opcode_error);
1123                     return false;
1124                 }
1125 
1126                 // The semantics of Alloca are:
1127                 //   Create a region R of virtual memory of type T, backed by a data buffer
1128                 //   Create a region P of virtual memory of type T*, backed by a data buffer
1129                 //   Write the virtual address of R into P
1130 
1131                 Type *T = alloca_inst->getAllocatedType();
1132                 Type *Tptr = alloca_inst->getType();
1133 
1134                 Memory::Region R = memory.Malloc(T);
1135 
1136                 if (R.IsInvalid())
1137                 {
1138                     if (log)
1139                         log->Printf("Couldn't allocate memory for an AllocaInst");
1140                     err.SetErrorToGenericError();
1141                     err.SetErrorString(memory_allocation_error);
1142                     return false;
1143                 }
1144 
1145                 Memory::Region P = memory.Malloc(Tptr);
1146 
1147                 if (P.IsInvalid())
1148                 {
1149                     if (log)
1150                         log->Printf("Couldn't allocate the result pointer for an AllocaInst");
1151                     err.SetErrorToGenericError();
1152                     err.SetErrorString(memory_allocation_error);
1153                     return false;
1154                 }
1155 
1156                 DataEncoderSP P_encoder = memory.GetEncoder(P);
1157 
1158                 if (P_encoder->PutAddress(0, R.m_base) == UINT32_MAX)
1159                 {
1160                     if (log)
1161                         log->Printf("Couldn't write the result pointer for an AllocaInst");
1162                     err.SetErrorToGenericError();
1163                     err.SetErrorString(memory_write_error);
1164                     return false;
1165                 }
1166 
1167                 frame.m_values[alloca_inst] = P;
1168 
1169                 if (log)
1170                 {
1171                     log->Printf("Interpreted an AllocaInst");
1172                     log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1173                     log->Printf("  P : %s", frame.SummarizeValue(alloca_inst).c_str());
1174                 }
1175             }
1176             break;
1177         case Instruction::BitCast:
1178             {
1179                 const BitCastInst *bit_cast_inst = dyn_cast<BitCastInst>(inst);
1180 
1181                 if (!bit_cast_inst)
1182                 {
1183                     if (log)
1184                         log->Printf("getOpcode() returns BitCast, but instruction is not a BitCastInst");
1185                     err.SetErrorToGenericError();
1186                     err.SetErrorString(interpreter_internal_error);
1187                     return false;
1188                 }
1189 
1190                 Value *source = bit_cast_inst->getOperand(0);
1191 
1192                 lldb_private::Scalar S;
1193 
1194                 if (!frame.EvaluateValue(S, source, llvm_module))
1195                 {
1196                     if (log)
1197                         log->Printf("Couldn't evaluate %s", PrintValue(source).c_str());
1198                     err.SetErrorToGenericError();
1199                     err.SetErrorString(bad_value_error);
1200                     return false;
1201                 }
1202 
1203                 frame.AssignValue(inst, S, llvm_module);
1204             }
1205             break;
1206         case Instruction::Br:
1207             {
1208                 const BranchInst *br_inst = dyn_cast<BranchInst>(inst);
1209 
1210                 if (!br_inst)
1211                 {
1212                     if (log)
1213                         log->Printf("getOpcode() returns Br, but instruction is not a BranchInst");
1214                     err.SetErrorToGenericError();
1215                     err.SetErrorString(interpreter_internal_error);
1216                     return false;
1217                 }
1218 
1219                 if (br_inst->isConditional())
1220                 {
1221                     Value *condition = br_inst->getCondition();
1222 
1223                     lldb_private::Scalar C;
1224 
1225                     if (!frame.EvaluateValue(C, condition, llvm_module))
1226                     {
1227                         if (log)
1228                             log->Printf("Couldn't evaluate %s", PrintValue(condition).c_str());
1229                         err.SetErrorToGenericError();
1230                         err.SetErrorString(bad_value_error);
1231                         return false;
1232                     }
1233 
1234                     if (C.GetRawBits64(0))
1235                         frame.Jump(br_inst->getSuccessor(0));
1236                     else
1237                         frame.Jump(br_inst->getSuccessor(1));
1238 
1239                     if (log)
1240                     {
1241                         log->Printf("Interpreted a BrInst with a condition");
1242                         log->Printf("  cond : %s", frame.SummarizeValue(condition).c_str());
1243                     }
1244                 }
1245                 else
1246                 {
1247                     frame.Jump(br_inst->getSuccessor(0));
1248 
1249                     if (log)
1250                     {
1251                         log->Printf("Interpreted a BrInst with no condition");
1252                     }
1253                 }
1254             }
1255             continue;
1256         case Instruction::GetElementPtr:
1257             {
1258                 const GetElementPtrInst *gep_inst = dyn_cast<GetElementPtrInst>(inst);
1259 
1260                 if (!gep_inst)
1261                 {
1262                     if (log)
1263                         log->Printf("getOpcode() returns GetElementPtr, but instruction is not a GetElementPtrInst");
1264                     err.SetErrorToGenericError();
1265                     err.SetErrorString(interpreter_internal_error);
1266                     return false;
1267                 }
1268 
1269                 const Value *pointer_operand = gep_inst->getPointerOperand();
1270                 Type *pointer_type = pointer_operand->getType();
1271 
1272                 lldb_private::Scalar P;
1273 
1274                 if (!frame.EvaluateValue(P, pointer_operand, llvm_module))
1275                 {
1276                     if (log)
1277                         log->Printf("Couldn't evaluate %s", PrintValue(pointer_operand).c_str());
1278                     err.SetErrorToGenericError();
1279                     err.SetErrorString(bad_value_error);
1280                     return false;
1281                 }
1282 
1283                 SmallVector <Value *, 8> indices (gep_inst->idx_begin(),
1284                                                   gep_inst->idx_end());
1285 
1286                 uint64_t offset = target_data.getIndexedOffset(pointer_type, indices);
1287 
1288                 lldb_private::Scalar Poffset = P + offset;
1289 
1290                 frame.AssignValue(inst, Poffset, llvm_module);
1291 
1292                 if (log)
1293                 {
1294                     log->Printf("Interpreted a GetElementPtrInst");
1295                     log->Printf("  P       : %s", frame.SummarizeValue(pointer_operand).c_str());
1296                     log->Printf("  Poffset : %s", frame.SummarizeValue(inst).c_str());
1297                 }
1298             }
1299             break;
1300         case Instruction::ICmp:
1301             {
1302                 const ICmpInst *icmp_inst = dyn_cast<ICmpInst>(inst);
1303 
1304                 if (!icmp_inst)
1305                 {
1306                     if (log)
1307                         log->Printf("getOpcode() returns ICmp, but instruction is not an ICmpInst");
1308                     err.SetErrorToGenericError();
1309                     err.SetErrorString(interpreter_internal_error);
1310                     return false;
1311                 }
1312 
1313                 CmpInst::Predicate predicate = icmp_inst->getPredicate();
1314 
1315                 Value *lhs = inst->getOperand(0);
1316                 Value *rhs = inst->getOperand(1);
1317 
1318                 lldb_private::Scalar L;
1319                 lldb_private::Scalar R;
1320 
1321                 if (!frame.EvaluateValue(L, lhs, llvm_module))
1322                 {
1323                     if (log)
1324                         log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
1325                     err.SetErrorToGenericError();
1326                     err.SetErrorString(bad_value_error);
1327                     return false;
1328                 }
1329 
1330                 if (!frame.EvaluateValue(R, rhs, llvm_module))
1331                 {
1332                     if (log)
1333                         log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
1334                     err.SetErrorToGenericError();
1335                     err.SetErrorString(bad_value_error);
1336                     return false;
1337                 }
1338 
1339                 lldb_private::Scalar result;
1340 
1341                 switch (predicate)
1342                 {
1343                 default:
1344                     return false;
1345                 case CmpInst::ICMP_EQ:
1346                     result = (L == R);
1347                     break;
1348                 case CmpInst::ICMP_NE:
1349                     result = (L != R);
1350                     break;
1351                 case CmpInst::ICMP_UGT:
1352                     result = (L.GetRawBits64(0) > R.GetRawBits64(0));
1353                     break;
1354                 case CmpInst::ICMP_UGE:
1355                     result = (L.GetRawBits64(0) >= R.GetRawBits64(0));
1356                     break;
1357                 case CmpInst::ICMP_ULT:
1358                     result = (L.GetRawBits64(0) < R.GetRawBits64(0));
1359                     break;
1360                 case CmpInst::ICMP_ULE:
1361                     result = (L.GetRawBits64(0) <= R.GetRawBits64(0));
1362                     break;
1363                 case CmpInst::ICMP_SGT:
1364                     result = (L > R);
1365                     break;
1366                 case CmpInst::ICMP_SGE:
1367                     result = (L >= R);
1368                     break;
1369                 case CmpInst::ICMP_SLT:
1370                     result = (L < R);
1371                     break;
1372                 case CmpInst::ICMP_SLE:
1373                     result = (L <= R);
1374                     break;
1375                 }
1376 
1377                 frame.AssignValue(inst, result, llvm_module);
1378 
1379                 if (log)
1380                 {
1381                     log->Printf("Interpreted an ICmpInst");
1382                     log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
1383                     log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
1384                     log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
1385                 }
1386             }
1387             break;
1388         case Instruction::IntToPtr:
1389             {
1390                 const IntToPtrInst *int_to_ptr_inst = dyn_cast<IntToPtrInst>(inst);
1391 
1392                 if (!int_to_ptr_inst)
1393                 {
1394                     if (log)
1395                         log->Printf("getOpcode() returns IntToPtr, but instruction is not an IntToPtrInst");
1396                     err.SetErrorToGenericError();
1397                     err.SetErrorString(interpreter_internal_error);
1398                     return false;
1399                 }
1400 
1401                 Value *src_operand = int_to_ptr_inst->getOperand(0);
1402 
1403                 lldb_private::Scalar I;
1404 
1405                 if (!frame.EvaluateValue(I, src_operand, llvm_module))
1406                 {
1407                     if (log)
1408                         log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
1409                     err.SetErrorToGenericError();
1410                     err.SetErrorString(bad_value_error);
1411                     return false;
1412                 }
1413 
1414                 frame.AssignValue(inst, I, llvm_module);
1415 
1416                 if (log)
1417                 {
1418                     log->Printf("Interpreted an IntToPtr");
1419                     log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1420                     log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1421                 }
1422             }
1423             break;
1424         case Instruction::Load:
1425             {
1426                 const LoadInst *load_inst = dyn_cast<LoadInst>(inst);
1427 
1428                 if (!load_inst)
1429                 {
1430                     if (log)
1431                         log->Printf("getOpcode() returns Load, but instruction is not a LoadInst");
1432                     err.SetErrorToGenericError();
1433                     err.SetErrorString(interpreter_internal_error);
1434                     return false;
1435                 }
1436 
1437                 // The semantics of Load are:
1438                 //   Create a region D that will contain the loaded data
1439                 //   Resolve the region P containing a pointer
1440                 //   Dereference P to get the region R that the data should be loaded from
1441                 //   Transfer a unit of type type(D) from R to D
1442 
1443                 const Value *pointer_operand = load_inst->getPointerOperand();
1444 
1445                 Type *pointer_ty = pointer_operand->getType();
1446                 PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1447                 if (!pointer_ptr_ty)
1448                 {
1449                     if (log)
1450                         log->Printf("getPointerOperand()->getType() is not a PointerType");
1451                     err.SetErrorToGenericError();
1452                     err.SetErrorString(interpreter_internal_error);
1453                     return false;
1454                 }
1455                 Type *target_ty = pointer_ptr_ty->getElementType();
1456 
1457                 Memory::Region D = frame.ResolveValue(load_inst, llvm_module);
1458                 Memory::Region P = frame.ResolveValue(pointer_operand, llvm_module);
1459 
1460                 if (D.IsInvalid())
1461                 {
1462                     if (log)
1463                         log->Printf("LoadInst's value doesn't resolve to anything");
1464                     err.SetErrorToGenericError();
1465                     err.SetErrorString(bad_value_error);
1466                     return false;
1467                 }
1468 
1469                 if (P.IsInvalid())
1470                 {
1471                     if (log)
1472                         log->Printf("LoadInst's pointer doesn't resolve to anything");
1473                     err.SetErrorToGenericError();
1474                     err.SetErrorString(bad_value_error);
1475                     return false;
1476                 }
1477 
1478                 DataExtractorSP P_extractor(memory.GetExtractor(P));
1479                 DataEncoderSP D_encoder(memory.GetEncoder(D));
1480 
1481                 uint32_t offset = 0;
1482                 lldb::addr_t pointer = P_extractor->GetAddress(&offset);
1483 
1484                 Memory::Region R = memory.Lookup(pointer, target_ty);
1485 
1486                 if (R.IsValid())
1487                 {
1488                     if (!memory.Read(D_encoder->GetDataStart(), R.m_base, target_data.getTypeStoreSize(target_ty)))
1489                     {
1490                         if (log)
1491                             log->Printf("Couldn't read from a region on behalf of a LoadInst");
1492                         err.SetErrorToGenericError();
1493                         err.SetErrorString(memory_read_error);
1494                         return false;
1495                     }
1496                 }
1497                 else
1498                 {
1499                     if (!memory.ReadFromRawPtr(D_encoder->GetDataStart(), pointer, target_data.getTypeStoreSize(target_ty)))
1500                     {
1501                         if (log)
1502                             log->Printf("Couldn't read from a raw pointer on behalf of a LoadInst");
1503                         err.SetErrorToGenericError();
1504                         err.SetErrorString(memory_read_error);
1505                         return false;
1506                     }
1507                 }
1508 
1509                 if (log)
1510                 {
1511                     log->Printf("Interpreted a LoadInst");
1512                     log->Printf("  P : %s", frame.SummarizeValue(pointer_operand).c_str());
1513                     if (R.IsValid())
1514                         log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1515                     else
1516                         log->Printf("  R : raw pointer 0x%llx", (unsigned long long)pointer);
1517                     log->Printf("  D : %s", frame.SummarizeValue(load_inst).c_str());
1518                 }
1519             }
1520             break;
1521         case Instruction::Ret:
1522             {
1523                 if (result_name.IsEmpty())
1524                     return true;
1525 
1526                 GlobalValue *result_value = llvm_module.getNamedValue(result_name.GetCString());
1527                 return frame.ConstructResult(result, result_value, result_name, result_type, llvm_module);
1528             }
1529         case Instruction::Store:
1530             {
1531                 const StoreInst *store_inst = dyn_cast<StoreInst>(inst);
1532 
1533                 if (!store_inst)
1534                 {
1535                     if (log)
1536                         log->Printf("getOpcode() returns Store, but instruction is not a StoreInst");
1537                     err.SetErrorToGenericError();
1538                     err.SetErrorString(interpreter_internal_error);
1539                     return false;
1540                 }
1541 
1542                 // The semantics of Store are:
1543                 //   Resolve the region D containing the data to be stored
1544                 //   Resolve the region P containing a pointer
1545                 //   Dereference P to get the region R that the data should be stored in
1546                 //   Transfer a unit of type type(D) from D to R
1547 
1548                 const Value *value_operand = store_inst->getValueOperand();
1549                 const Value *pointer_operand = store_inst->getPointerOperand();
1550 
1551                 Type *pointer_ty = pointer_operand->getType();
1552                 PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1553                 if (!pointer_ptr_ty)
1554                     return false;
1555                 Type *target_ty = pointer_ptr_ty->getElementType();
1556 
1557                 Memory::Region D = frame.ResolveValue(value_operand, llvm_module);
1558                 Memory::Region P = frame.ResolveValue(pointer_operand, llvm_module);
1559 
1560                 if (D.IsInvalid())
1561                 {
1562                     if (log)
1563                         log->Printf("StoreInst's value doesn't resolve to anything");
1564                     err.SetErrorToGenericError();
1565                     err.SetErrorString(bad_value_error);
1566                     return false;
1567                 }
1568 
1569                 if (P.IsInvalid())
1570                 {
1571                     if (log)
1572                         log->Printf("StoreInst's pointer doesn't resolve to anything");
1573                     err.SetErrorToGenericError();
1574                     err.SetErrorString(bad_value_error);
1575                     return false;
1576                 }
1577 
1578                 DataExtractorSP P_extractor(memory.GetExtractor(P));
1579                 DataExtractorSP D_extractor(memory.GetExtractor(D));
1580 
1581                 if (!P_extractor || !D_extractor)
1582                     return false;
1583 
1584                 uint32_t offset = 0;
1585                 lldb::addr_t pointer = P_extractor->GetAddress(&offset);
1586 
1587                 Memory::Region R = memory.Lookup(pointer, target_ty);
1588 
1589                 if (R.IsValid())
1590                 {
1591                     if (!memory.Write(R.m_base, D_extractor->GetDataStart(), target_data.getTypeStoreSize(target_ty)))
1592                     {
1593                         if (log)
1594                             log->Printf("Couldn't write to a region on behalf of a LoadInst");
1595                         err.SetErrorToGenericError();
1596                         err.SetErrorString(memory_write_error);
1597                         return false;
1598                     }
1599                 }
1600                 else
1601                 {
1602                     if (!memory.WriteToRawPtr(pointer, D_extractor->GetDataStart(), target_data.getTypeStoreSize(target_ty)))
1603                     {
1604                         if (log)
1605                             log->Printf("Couldn't write to a raw pointer on behalf of a LoadInst");
1606                         err.SetErrorToGenericError();
1607                         err.SetErrorString(memory_write_error);
1608                         return false;
1609                     }
1610                 }
1611 
1612 
1613                 if (log)
1614                 {
1615                     log->Printf("Interpreted a StoreInst");
1616                     log->Printf("  D : %s", frame.SummarizeValue(value_operand).c_str());
1617                     log->Printf("  P : %s", frame.SummarizeValue(pointer_operand).c_str());
1618                     log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1619                 }
1620             }
1621             break;
1622         }
1623 
1624         ++frame.m_ii;
1625     }
1626 
1627     if (num_insts >= 4096)
1628     {
1629         err.SetErrorToGenericError();
1630         err.SetErrorString(infinite_loop_error);
1631         return false;
1632     }
1633 
1634     return false;
1635 }
1636