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/ClangExpressionVariable.h"
15 #include "lldb/Expression/IRForTarget.h"
16 #include "lldb/Expression/IRInterpreter.h"
17 
18 #include "llvm/IR/Constants.h"
19 #include "llvm/IR/Function.h"
20 #include "llvm/IR/Instructions.h"
21 #include "llvm/IR/Module.h"
22 #include "llvm/Support/raw_ostream.h"
23 #include "llvm/IR/DataLayout.h"
24 
25 #include <map>
26 
27 using namespace llvm;
28 
29 IRInterpreter::IRInterpreter(lldb_private::ClangExpressionDeclMap &decl_map,
30                                            lldb_private::Stream *error_stream) :
31     m_decl_map(decl_map)
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 STD_SHARED_PTR(lldb_private::DataEncoder) DataEncoderSP;
73 typedef STD_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 STD_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 (bool) m_allocation;
162         }
163 
164         bool IsInvalid ()
165         {
166             return !m_allocation;
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     DataLayout         &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 (DataLayout &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(0));
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("%" PRIx64 " [%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     DataLayout                             &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 (DataLayout &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(0));
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             lldb::offset_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(region.m_extent, 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         if (buf.GetByteSize() > region_encoder->GetByteSize())
537             return false; // This should not happen
538 
539         memcpy(region_encoder->GetDataStart(), buf.GetBytes(), buf.GetByteSize());
540 
541         return true;
542     }
543 
544     bool ResolveConstantValue (APInt &value, const Constant *constant)
545     {
546         if (const ConstantInt *constant_int = dyn_cast<ConstantInt>(constant))
547         {
548             value = constant_int->getValue();
549             return true;
550         }
551         else if (const ConstantFP *constant_fp = dyn_cast<ConstantFP>(constant))
552         {
553             value = constant_fp->getValueAPF().bitcastToAPInt();
554             return true;
555         }
556         else if (const ConstantExpr *constant_expr = dyn_cast<ConstantExpr>(constant))
557         {
558             switch (constant_expr->getOpcode())
559             {
560                 default:
561                     return false;
562                 case Instruction::IntToPtr:
563                 case Instruction::PtrToInt:
564                 case Instruction::BitCast:
565                     return ResolveConstantValue(value, constant_expr->getOperand(0));
566                 case Instruction::GetElementPtr:
567                 {
568                     ConstantExpr::const_op_iterator op_cursor = constant_expr->op_begin();
569                     ConstantExpr::const_op_iterator op_end = constant_expr->op_end();
570 
571                     Constant *base = dyn_cast<Constant>(*op_cursor);
572 
573                     if (!base)
574                         return false;
575 
576                     if (!ResolveConstantValue(value, base))
577                         return false;
578 
579                     op_cursor++;
580 
581                     if (op_cursor == op_end)
582                         return true; // no offset to apply!
583 
584                     SmallVector <Value *, 8> indices (op_cursor, op_end);
585 
586                     uint64_t offset = m_target_data.getIndexedOffset(base->getType(), indices);
587 
588                     const bool is_signed = true;
589                     value += APInt(value.getBitWidth(), offset, is_signed);
590 
591                     return true;
592                 }
593             }
594         }
595 
596         return false;
597     }
598 
599     bool ResolveConstant (Memory::Region &region, const Constant *constant)
600     {
601         APInt resolved_value;
602 
603         if (!ResolveConstantValue(resolved_value, constant))
604             return false;
605 
606         const uint64_t *raw_data = resolved_value.getRawData();
607 
608         size_t constant_size = m_target_data.getTypeStoreSize(constant->getType());
609         return m_memory.Write(region.m_base, (const uint8_t*)raw_data, constant_size);
610     }
611 
612     Memory::Region ResolveValue (const Value *value, Module &module)
613     {
614         ValueMap::iterator i = m_values.find(value);
615 
616         if (i != m_values.end())
617             return i->second;
618 
619         const GlobalValue *global_value = dyn_cast<GlobalValue>(value);
620 
621         // If the variable is indirected through the argument
622         // array then we need to build an extra level of indirection
623         // for it.  This is the default; only magic arguments like
624         // "this", "self", and "_cmd" are direct.
625         bool variable_is_this = false;
626 
627         // Attempt to resolve the value using the program's data.
628         // If it is, the values to be created are:
629         //
630         // data_region - a region of memory in which the variable's data resides.
631         // ref_region - a region of memory in which its address (i.e., &var) resides.
632         //   In the JIT case, this region would be a member of the struct passed in.
633         // pointer_region - a region of memory in which the address of the pointer
634         //   resides.  This is an IR-level variable.
635         do
636         {
637             lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
638 
639             lldb_private::Value resolved_value;
640             lldb_private::ClangExpressionVariable::FlagType flags = 0;
641 
642             if (global_value)
643             {
644                 clang::NamedDecl *decl = IRForTarget::DeclForGlobal(global_value, &module);
645 
646                 if (!decl)
647                     break;
648 
649                 if (isa<clang::FunctionDecl>(decl))
650                 {
651                     if (log)
652                         log->Printf("The interpreter does not handle function pointers at the moment");
653 
654                     return Memory::Region();
655                 }
656 
657                 resolved_value = m_decl_map.LookupDecl(decl, flags);
658             }
659             else
660             {
661                 // Special-case "this", "self", and "_cmd"
662 
663                 std::string name_str = value->getName().str();
664 
665                 if (name_str == "this" ||
666                     name_str == "self" ||
667                     name_str == "_cmd")
668                 {
669                     resolved_value = m_decl_map.GetSpecialValue(lldb_private::ConstString(name_str.c_str()));
670                     variable_is_this = true;
671                 }
672             }
673 
674             if (resolved_value.GetScalar().GetType() != lldb_private::Scalar::e_void)
675             {
676                 if (resolved_value.GetContextType() == lldb_private::Value::eContextTypeRegisterInfo)
677                 {
678                     if (variable_is_this)
679                     {
680                         Memory::Region data_region = m_memory.Place(value->getType(), resolved_value.GetScalar().ULongLong(), resolved_value);
681 
682                         lldb_private::Value origin;
683 
684                         origin.SetValueType(lldb_private::Value::eValueTypeLoadAddress);
685                         origin.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
686                         origin.GetScalar() = resolved_value.GetScalar();
687 
688                         data_region.m_allocation->m_origin = origin;
689 
690                         Memory::Region ref_region = m_memory.Malloc(value->getType());
691 
692                         if (ref_region.IsInvalid())
693                             return Memory::Region();
694 
695                         DataEncoderSP ref_encoder = m_memory.GetEncoder(ref_region);
696 
697                         if (ref_encoder->PutAddress(0, data_region.m_base) == UINT32_MAX)
698                             return Memory::Region();
699 
700                         if (log)
701                         {
702                             log->Printf("Made an allocation for \"this\" register variable %s", PrintValue(value).c_str());
703                             log->Printf("  Data region    : %llx", (unsigned long long)data_region.m_base);
704                             log->Printf("  Ref region     : %llx", (unsigned long long)ref_region.m_base);
705                         }
706 
707                         m_values[value] = ref_region;
708                         return ref_region;
709                     }
710                     else if (flags & lldb_private::ClangExpressionVariable::EVBareRegister)
711                     {
712                         lldb_private::RegisterInfo *reg_info = resolved_value.GetRegisterInfo();
713                         Memory::Region data_region = (reg_info->encoding == lldb::eEncodingVector) ?
714                         m_memory.Malloc(reg_info->byte_size, m_target_data.getPrefTypeAlignment(value->getType())) :
715                         m_memory.Malloc(value->getType());
716 
717                         data_region.m_allocation->m_origin = resolved_value;
718                         Memory::Region ref_region = m_memory.Malloc(value->getType());
719 
720                         if (!Cache(data_region.m_allocation, value->getType()))
721                             return Memory::Region();
722 
723                         if (ref_region.IsInvalid())
724                             return Memory::Region();
725 
726                         DataEncoderSP ref_encoder = m_memory.GetEncoder(ref_region);
727 
728                         if (ref_encoder->PutAddress(0, data_region.m_base) == UINT32_MAX)
729                             return Memory::Region();
730 
731                         if (log)
732                         {
733                             log->Printf("Made an allocation for bare register variable %s", PrintValue(value).c_str());
734                             log->Printf("  Data contents  : %s", m_memory.PrintData(data_region.m_base, data_region.m_extent).c_str());
735                             log->Printf("  Data region    : %llx", (unsigned long long)data_region.m_base);
736                             log->Printf("  Ref region     : %llx", (unsigned long long)ref_region.m_base);
737                         }
738 
739                         m_values[value] = ref_region;
740                         return ref_region;
741                     }
742                     else
743                     {
744                         lldb_private::RegisterInfo *reg_info = resolved_value.GetRegisterInfo();
745                         Memory::Region data_region = (reg_info->encoding == lldb::eEncodingVector) ?
746                         m_memory.Malloc(reg_info->byte_size, m_target_data.getPrefTypeAlignment(value->getType())) :
747                         m_memory.Malloc(value->getType());
748 
749                         data_region.m_allocation->m_origin = resolved_value;
750                         Memory::Region ref_region = m_memory.Malloc(value->getType());
751                         Memory::Region pointer_region;
752 
753                         pointer_region = m_memory.Malloc(value->getType());
754 
755                         if (!Cache(data_region.m_allocation, value->getType()))
756                             return Memory::Region();
757 
758                         if (ref_region.IsInvalid())
759                             return Memory::Region();
760 
761                         if (pointer_region.IsInvalid())
762                             return Memory::Region();
763 
764                         DataEncoderSP ref_encoder = m_memory.GetEncoder(ref_region);
765 
766                         if (ref_encoder->PutAddress(0, data_region.m_base) == UINT32_MAX)
767                             return Memory::Region();
768 
769                         if (log)
770                         {
771                             log->Printf("Made an allocation for ordinary register variable %s", PrintValue(value).c_str());
772                             log->Printf("  Data contents  : %s", m_memory.PrintData(data_region.m_base, data_region.m_extent).c_str());
773                             log->Printf("  Data region    : %llx", (unsigned long long)data_region.m_base);
774                             log->Printf("  Ref region     : %llx", (unsigned long long)ref_region.m_base);
775                             log->Printf("  Pointer region : %llx", (unsigned long long)pointer_region.m_base);
776                         }
777 
778                         DataEncoderSP pointer_encoder = m_memory.GetEncoder(pointer_region);
779 
780                         if (pointer_encoder->PutAddress(0, ref_region.m_base) == UINT32_MAX)
781                             return Memory::Region();
782 
783                         m_values[value] = pointer_region;
784                         return pointer_region;
785                     }
786                 }
787                 else
788                 {
789                     Memory::Region data_region = m_memory.Place(value->getType(), resolved_value.GetScalar().ULongLong(), resolved_value);
790                     Memory::Region ref_region = m_memory.Malloc(value->getType());
791                     Memory::Region pointer_region;
792 
793                     if (!variable_is_this)
794                         pointer_region = m_memory.Malloc(value->getType());
795 
796                     if (ref_region.IsInvalid())
797                         return Memory::Region();
798 
799                     if (pointer_region.IsInvalid() && !variable_is_this)
800                         return Memory::Region();
801 
802                     DataEncoderSP ref_encoder = m_memory.GetEncoder(ref_region);
803 
804                     if (ref_encoder->PutAddress(0, data_region.m_base) == UINT32_MAX)
805                         return Memory::Region();
806 
807                     if (!variable_is_this)
808                     {
809                         DataEncoderSP pointer_encoder = m_memory.GetEncoder(pointer_region);
810 
811                         if (pointer_encoder->PutAddress(0, ref_region.m_base) == UINT32_MAX)
812                             return Memory::Region();
813 
814                         m_values[value] = pointer_region;
815                     }
816 
817                     if (log)
818                     {
819                         log->Printf("Made an allocation for %s", PrintValue(value).c_str());
820                         log->Printf("  Data contents  : %s", m_memory.PrintData(data_region.m_base, data_region.m_extent).c_str());
821                         log->Printf("  Data region    : %llx", (unsigned long long)data_region.m_base);
822                         log->Printf("  Ref region     : %llx", (unsigned long long)ref_region.m_base);
823                         if (!variable_is_this)
824                             log->Printf("  Pointer region : %llx", (unsigned long long)pointer_region.m_base);
825                     }
826 
827                     if (variable_is_this)
828                         return ref_region;
829                     else
830                         return pointer_region;
831                 }
832             }
833         }
834         while(0);
835 
836         // Fall back and allocate space [allocation type Alloca]
837 
838         Type *type = value->getType();
839 
840         Memory::Region data_region = m_memory.Malloc(type);
841         data_region.m_allocation->m_origin.GetScalar() = (unsigned long long)data_region.m_allocation->m_data->GetBytes();
842         data_region.m_allocation->m_origin.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
843         data_region.m_allocation->m_origin.SetValueType(lldb_private::Value::eValueTypeHostAddress);
844 
845         const Constant *constant = dyn_cast<Constant>(value);
846 
847         do
848         {
849             if (!constant)
850                 break;
851 
852             if (!ResolveConstant (data_region, constant))
853                 return Memory::Region();
854         }
855         while(0);
856 
857         m_values[value] = data_region;
858         return data_region;
859     }
860 
861     bool ConstructResult (lldb::ClangExpressionVariableSP &result,
862                           const GlobalValue *result_value,
863                           const lldb_private::ConstString &result_name,
864                           lldb_private::TypeFromParser result_type,
865                           Module &module)
866     {
867         // The result_value resolves to P, a pointer to a region R containing the result data.
868         // If the result variable is a reference, the region R contains a pointer to the result R_final in the original process.
869 
870         if (!result_value)
871             return true; // There was no slot for a result – the expression doesn't return one.
872 
873         ValueMap::iterator i = m_values.find(result_value);
874 
875         if (i == m_values.end())
876             return false; // There was a slot for the result, but we didn't write into it.
877 
878         Memory::Region P = i->second;
879         DataExtractorSP P_extractor = m_memory.GetExtractor(P);
880 
881         if (!P_extractor)
882             return false;
883 
884         Type *pointer_ty = result_value->getType();
885         PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
886         if (!pointer_ptr_ty)
887             return false;
888         Type *R_ty = pointer_ptr_ty->getElementType();
889 
890         lldb::offset_t offset = 0;
891         lldb::addr_t pointer = P_extractor->GetAddress(&offset);
892 
893         Memory::Region R = m_memory.Lookup(pointer, R_ty);
894 
895         if (R.m_allocation->m_origin.GetValueType() != lldb_private::Value::eValueTypeHostAddress ||
896             !R.m_allocation->m_data)
897             return false;
898 
899         lldb_private::Value base;
900 
901         bool transient = false;
902         bool maybe_make_load = false;
903 
904         if (m_decl_map.ResultIsReference(result_name))
905         {
906             PointerType *R_ptr_ty = dyn_cast<PointerType>(R_ty);
907             if (!R_ptr_ty)
908                 return false;
909             Type *R_final_ty = R_ptr_ty->getElementType();
910 
911             DataExtractorSP R_extractor = m_memory.GetExtractor(R);
912 
913             if (!R_extractor)
914                 return false;
915 
916             offset = 0;
917             lldb::addr_t R_pointer = R_extractor->GetAddress(&offset);
918 
919             Memory::Region R_final = m_memory.Lookup(R_pointer, R_final_ty);
920 
921             if (R_final.m_allocation)
922             {
923                 if (R_final.m_allocation->m_data)
924                     transient = true; // this is a stack allocation
925 
926                 base = R_final.m_allocation->m_origin;
927                 base.GetScalar() += (R_final.m_base - R_final.m_allocation->m_virtual_address);
928             }
929             else
930             {
931                 // We got a bare pointer.  We are going to treat it as a load address
932                 // or a file address, letting decl_map make the choice based on whether
933                 // or not a process exists.
934 
935                 base.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
936                 base.SetValueType(lldb_private::Value::eValueTypeFileAddress);
937                 base.GetScalar() = (unsigned long long)R_pointer;
938                 maybe_make_load = true;
939             }
940         }
941         else
942         {
943             base.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
944             base.SetValueType(lldb_private::Value::eValueTypeHostAddress);
945             base.GetScalar() = (unsigned long long)R.m_allocation->m_data->GetBytes() + (R.m_base - R.m_allocation->m_virtual_address);
946         }
947 
948         return m_decl_map.CompleteResultVariable (result, base, result_name, result_type, transient, maybe_make_load);
949     }
950 };
951 
952 bool
953 IRInterpreter::maybeRunOnFunction (lldb::ClangExpressionVariableSP &result,
954                                    const lldb_private::ConstString &result_name,
955                                    lldb_private::TypeFromParser result_type,
956                                    Function &llvm_function,
957                                    Module &llvm_module,
958                                    lldb_private::Error &err)
959 {
960     if (supportsFunction (llvm_function, err))
961         return runOnFunction(result,
962                              result_name,
963                              result_type,
964                              llvm_function,
965                              llvm_module,
966                              err);
967     else
968         return false;
969 }
970 
971 static const char *unsupported_opcode_error         = "Interpreter doesn't handle one of the expression's opcodes";
972 static const char *interpreter_initialization_error = "Interpreter couldn't be initialized";
973 static const char *interpreter_internal_error       = "Interpreter encountered an internal error";
974 static const char *bad_value_error                  = "Interpreter couldn't resolve a value during execution";
975 static const char *memory_allocation_error          = "Interpreter couldn't allocate memory";
976 static const char *memory_write_error               = "Interpreter couldn't write to memory";
977 static const char *memory_read_error                = "Interpreter couldn't read from memory";
978 static const char *infinite_loop_error              = "Interpreter ran for too many cycles";
979 static const char *bad_result_error                 = "Result of expression is in bad memory";
980 
981 bool
982 IRInterpreter::supportsFunction (Function &llvm_function,
983                                  lldb_private::Error &err)
984 {
985     lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
986 
987     for (Function::iterator bbi = llvm_function.begin(), bbe = llvm_function.end();
988          bbi != bbe;
989          ++bbi)
990     {
991         for (BasicBlock::iterator ii = bbi->begin(), ie = bbi->end();
992              ii != ie;
993              ++ii)
994         {
995             switch (ii->getOpcode())
996             {
997             default:
998                 {
999                     if (log)
1000                         log->Printf("Unsupported instruction: %s", PrintValue(ii).c_str());
1001                     err.SetErrorToGenericError();
1002                     err.SetErrorString(unsupported_opcode_error);
1003                     return false;
1004                 }
1005             case Instruction::Add:
1006             case Instruction::Alloca:
1007             case Instruction::BitCast:
1008             case Instruction::Br:
1009             case Instruction::GetElementPtr:
1010                 break;
1011             case Instruction::ICmp:
1012                 {
1013                     ICmpInst *icmp_inst = dyn_cast<ICmpInst>(ii);
1014 
1015                     if (!icmp_inst)
1016                     {
1017                         err.SetErrorToGenericError();
1018                         err.SetErrorString(interpreter_internal_error);
1019                         return false;
1020                     }
1021 
1022                     switch (icmp_inst->getPredicate())
1023                     {
1024                     default:
1025                         {
1026                             if (log)
1027                                 log->Printf("Unsupported ICmp predicate: %s", PrintValue(ii).c_str());
1028 
1029                             err.SetErrorToGenericError();
1030                             err.SetErrorString(unsupported_opcode_error);
1031                             return false;
1032                         }
1033                     case CmpInst::ICMP_EQ:
1034                     case CmpInst::ICMP_NE:
1035                     case CmpInst::ICMP_UGT:
1036                     case CmpInst::ICMP_UGE:
1037                     case CmpInst::ICMP_ULT:
1038                     case CmpInst::ICMP_ULE:
1039                     case CmpInst::ICMP_SGT:
1040                     case CmpInst::ICMP_SGE:
1041                     case CmpInst::ICMP_SLT:
1042                     case CmpInst::ICMP_SLE:
1043                         break;
1044                     }
1045                 }
1046                 break;
1047             case Instruction::And:
1048             case Instruction::AShr:
1049             case Instruction::IntToPtr:
1050             case Instruction::PtrToInt:
1051             case Instruction::Load:
1052             case Instruction::LShr:
1053             case Instruction::Mul:
1054             case Instruction::Or:
1055             case Instruction::Ret:
1056             case Instruction::SDiv:
1057             case Instruction::Shl:
1058             case Instruction::SRem:
1059             case Instruction::Store:
1060             case Instruction::Sub:
1061             case Instruction::UDiv:
1062             case Instruction::URem:
1063             case Instruction::Xor:
1064             case Instruction::ZExt:
1065                 break;
1066             }
1067         }
1068     }
1069 
1070     return true;
1071 }
1072 
1073 bool
1074 IRInterpreter::runOnFunction (lldb::ClangExpressionVariableSP &result,
1075                               const lldb_private::ConstString &result_name,
1076                               lldb_private::TypeFromParser result_type,
1077                               Function &llvm_function,
1078                               Module &llvm_module,
1079                               lldb_private::Error &err)
1080 {
1081     lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
1082 
1083     lldb_private::ClangExpressionDeclMap::TargetInfo target_info = m_decl_map.GetTargetInfo();
1084 
1085     if (!target_info.IsValid())
1086     {
1087         err.SetErrorToGenericError();
1088         err.SetErrorString(interpreter_initialization_error);
1089         return false;
1090     }
1091 
1092     lldb::addr_t alloc_min;
1093     lldb::addr_t alloc_max;
1094 
1095     switch (target_info.address_byte_size)
1096     {
1097     default:
1098         err.SetErrorToGenericError();
1099         err.SetErrorString(interpreter_initialization_error);
1100         return false;
1101     case 4:
1102         alloc_min = 0x00001000llu;
1103         alloc_max = 0x0000ffffllu;
1104         break;
1105     case 8:
1106         alloc_min = 0x0000000000001000llu;
1107         alloc_max = 0x000000000000ffffllu;
1108         break;
1109     }
1110 
1111     DataLayout target_data(&llvm_module);
1112     if (target_data.getPointerSize(0) != target_info.address_byte_size)
1113     {
1114         err.SetErrorToGenericError();
1115         err.SetErrorString(interpreter_initialization_error);
1116         return false;
1117     }
1118     if (target_data.isLittleEndian() != (target_info.byte_order == lldb::eByteOrderLittle))
1119     {
1120         err.SetErrorToGenericError();
1121         err.SetErrorString(interpreter_initialization_error);
1122         return false;
1123     }
1124 
1125     Memory memory(target_data, m_decl_map, alloc_min, alloc_max);
1126     InterpreterStackFrame frame(target_data, memory, m_decl_map);
1127 
1128     uint32_t num_insts = 0;
1129 
1130     frame.Jump(llvm_function.begin());
1131 
1132     while (frame.m_ii != frame.m_ie && (++num_insts < 4096))
1133     {
1134         const Instruction *inst = frame.m_ii;
1135 
1136         if (log)
1137             log->Printf("Interpreting %s", PrintValue(inst).c_str());
1138 
1139         switch (inst->getOpcode())
1140         {
1141         default:
1142             break;
1143         case Instruction::Add:
1144         case Instruction::Sub:
1145         case Instruction::Mul:
1146         case Instruction::SDiv:
1147         case Instruction::UDiv:
1148         case Instruction::SRem:
1149         case Instruction::URem:
1150         case Instruction::Shl:
1151         case Instruction::LShr:
1152         case Instruction::AShr:
1153         case Instruction::And:
1154         case Instruction::Or:
1155         case Instruction::Xor:
1156             {
1157                 const BinaryOperator *bin_op = dyn_cast<BinaryOperator>(inst);
1158 
1159                 if (!bin_op)
1160                 {
1161                     if (log)
1162                         log->Printf("getOpcode() returns %s, but instruction is not a BinaryOperator", inst->getOpcodeName());
1163                     err.SetErrorToGenericError();
1164                     err.SetErrorString(interpreter_internal_error);
1165                     return false;
1166                 }
1167 
1168                 Value *lhs = inst->getOperand(0);
1169                 Value *rhs = inst->getOperand(1);
1170 
1171                 lldb_private::Scalar L;
1172                 lldb_private::Scalar R;
1173 
1174                 if (!frame.EvaluateValue(L, lhs, llvm_module))
1175                 {
1176                     if (log)
1177                         log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
1178                     err.SetErrorToGenericError();
1179                     err.SetErrorString(bad_value_error);
1180                     return false;
1181                 }
1182 
1183                 if (!frame.EvaluateValue(R, rhs, llvm_module))
1184                 {
1185                     if (log)
1186                         log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
1187                     err.SetErrorToGenericError();
1188                     err.SetErrorString(bad_value_error);
1189                     return false;
1190                 }
1191 
1192                 lldb_private::Scalar result;
1193 
1194                 switch (inst->getOpcode())
1195                 {
1196                 default:
1197                     break;
1198                 case Instruction::Add:
1199                     result = L + R;
1200                     break;
1201                 case Instruction::Mul:
1202                     result = L * R;
1203                     break;
1204                 case Instruction::Sub:
1205                     result = L - R;
1206                     break;
1207                 case Instruction::SDiv:
1208                     result = L / R;
1209                     break;
1210                 case Instruction::UDiv:
1211                     result = L.GetRawBits64(0) / R.GetRawBits64(1);
1212                     break;
1213                 case Instruction::SRem:
1214                     result = L % R;
1215                     break;
1216                 case Instruction::URem:
1217                     result = L.GetRawBits64(0) % R.GetRawBits64(1);
1218                     break;
1219                 case Instruction::Shl:
1220                     result = L << R;
1221                     break;
1222                 case Instruction::AShr:
1223                     result = L >> R;
1224                     break;
1225                 case Instruction::LShr:
1226                     result = L;
1227                     result.ShiftRightLogical(R);
1228                     break;
1229                 case Instruction::And:
1230                     result = L & R;
1231                     break;
1232                 case Instruction::Or:
1233                     result = L | R;
1234                     break;
1235                 case Instruction::Xor:
1236                     result = L ^ R;
1237                     break;
1238                 }
1239 
1240                 frame.AssignValue(inst, result, llvm_module);
1241 
1242                 if (log)
1243                 {
1244                     log->Printf("Interpreted a %s", inst->getOpcodeName());
1245                     log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
1246                     log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
1247                     log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
1248                 }
1249             }
1250             break;
1251         case Instruction::Alloca:
1252             {
1253                 const AllocaInst *alloca_inst = dyn_cast<AllocaInst>(inst);
1254 
1255                 if (!alloca_inst)
1256                 {
1257                     if (log)
1258                         log->Printf("getOpcode() returns Alloca, but instruction is not an AllocaInst");
1259                     err.SetErrorToGenericError();
1260                     err.SetErrorString(interpreter_internal_error);
1261                     return false;
1262                 }
1263 
1264                 if (alloca_inst->isArrayAllocation())
1265                 {
1266                     if (log)
1267                         log->Printf("AllocaInsts are not handled if isArrayAllocation() is true");
1268                     err.SetErrorToGenericError();
1269                     err.SetErrorString(unsupported_opcode_error);
1270                     return false;
1271                 }
1272 
1273                 // The semantics of Alloca are:
1274                 //   Create a region R of virtual memory of type T, backed by a data buffer
1275                 //   Create a region P of virtual memory of type T*, backed by a data buffer
1276                 //   Write the virtual address of R into P
1277 
1278                 Type *T = alloca_inst->getAllocatedType();
1279                 Type *Tptr = alloca_inst->getType();
1280 
1281                 Memory::Region R = memory.Malloc(T);
1282 
1283                 if (R.IsInvalid())
1284                 {
1285                     if (log)
1286                         log->Printf("Couldn't allocate memory for an AllocaInst");
1287                     err.SetErrorToGenericError();
1288                     err.SetErrorString(memory_allocation_error);
1289                     return false;
1290                 }
1291 
1292                 Memory::Region P = memory.Malloc(Tptr);
1293 
1294                 if (P.IsInvalid())
1295                 {
1296                     if (log)
1297                         log->Printf("Couldn't allocate the result pointer for an AllocaInst");
1298                     err.SetErrorToGenericError();
1299                     err.SetErrorString(memory_allocation_error);
1300                     return false;
1301                 }
1302 
1303                 DataEncoderSP P_encoder = memory.GetEncoder(P);
1304 
1305                 if (P_encoder->PutAddress(0, R.m_base) == UINT32_MAX)
1306                 {
1307                     if (log)
1308                         log->Printf("Couldn't write the result pointer for an AllocaInst");
1309                     err.SetErrorToGenericError();
1310                     err.SetErrorString(memory_write_error);
1311                     return false;
1312                 }
1313 
1314                 frame.m_values[alloca_inst] = P;
1315 
1316                 if (log)
1317                 {
1318                     log->Printf("Interpreted an AllocaInst");
1319                     log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1320                     log->Printf("  P : %s", frame.SummarizeValue(alloca_inst).c_str());
1321                 }
1322             }
1323             break;
1324         case Instruction::BitCast:
1325         case Instruction::ZExt:
1326             {
1327                 const CastInst *cast_inst = dyn_cast<CastInst>(inst);
1328 
1329                 if (!cast_inst)
1330                 {
1331                     if (log)
1332                         log->Printf("getOpcode() returns %s, but instruction is not a BitCastInst", cast_inst->getOpcodeName());
1333                     err.SetErrorToGenericError();
1334                     err.SetErrorString(interpreter_internal_error);
1335                     return false;
1336                 }
1337 
1338                 Value *source = cast_inst->getOperand(0);
1339 
1340                 lldb_private::Scalar S;
1341 
1342                 if (!frame.EvaluateValue(S, source, llvm_module))
1343                 {
1344                     if (log)
1345                         log->Printf("Couldn't evaluate %s", PrintValue(source).c_str());
1346                     err.SetErrorToGenericError();
1347                     err.SetErrorString(bad_value_error);
1348                     return false;
1349                 }
1350 
1351                 frame.AssignValue(inst, S, llvm_module);
1352             }
1353             break;
1354         case Instruction::Br:
1355             {
1356                 const BranchInst *br_inst = dyn_cast<BranchInst>(inst);
1357 
1358                 if (!br_inst)
1359                 {
1360                     if (log)
1361                         log->Printf("getOpcode() returns Br, but instruction is not a BranchInst");
1362                     err.SetErrorToGenericError();
1363                     err.SetErrorString(interpreter_internal_error);
1364                     return false;
1365                 }
1366 
1367                 if (br_inst->isConditional())
1368                 {
1369                     Value *condition = br_inst->getCondition();
1370 
1371                     lldb_private::Scalar C;
1372 
1373                     if (!frame.EvaluateValue(C, condition, llvm_module))
1374                     {
1375                         if (log)
1376                             log->Printf("Couldn't evaluate %s", PrintValue(condition).c_str());
1377                         err.SetErrorToGenericError();
1378                         err.SetErrorString(bad_value_error);
1379                         return false;
1380                     }
1381 
1382                     if (C.GetRawBits64(0))
1383                         frame.Jump(br_inst->getSuccessor(0));
1384                     else
1385                         frame.Jump(br_inst->getSuccessor(1));
1386 
1387                     if (log)
1388                     {
1389                         log->Printf("Interpreted a BrInst with a condition");
1390                         log->Printf("  cond : %s", frame.SummarizeValue(condition).c_str());
1391                     }
1392                 }
1393                 else
1394                 {
1395                     frame.Jump(br_inst->getSuccessor(0));
1396 
1397                     if (log)
1398                     {
1399                         log->Printf("Interpreted a BrInst with no condition");
1400                     }
1401                 }
1402             }
1403             continue;
1404         case Instruction::GetElementPtr:
1405             {
1406                 const GetElementPtrInst *gep_inst = dyn_cast<GetElementPtrInst>(inst);
1407 
1408                 if (!gep_inst)
1409                 {
1410                     if (log)
1411                         log->Printf("getOpcode() returns GetElementPtr, but instruction is not a GetElementPtrInst");
1412                     err.SetErrorToGenericError();
1413                     err.SetErrorString(interpreter_internal_error);
1414                     return false;
1415                 }
1416 
1417                 const Value *pointer_operand = gep_inst->getPointerOperand();
1418                 Type *pointer_type = pointer_operand->getType();
1419 
1420                 lldb_private::Scalar P;
1421 
1422                 if (!frame.EvaluateValue(P, pointer_operand, llvm_module))
1423                 {
1424                     if (log)
1425                         log->Printf("Couldn't evaluate %s", PrintValue(pointer_operand).c_str());
1426                     err.SetErrorToGenericError();
1427                     err.SetErrorString(bad_value_error);
1428                     return false;
1429                 }
1430 
1431                 typedef SmallVector <Value *, 8> IndexVector;
1432                 typedef IndexVector::iterator IndexIterator;
1433 
1434                 SmallVector <Value *, 8> indices (gep_inst->idx_begin(),
1435                                                   gep_inst->idx_end());
1436 
1437                 SmallVector <Value *, 8> const_indices;
1438 
1439                 for (IndexIterator ii = indices.begin(), ie = indices.end();
1440                      ii != ie;
1441                      ++ii)
1442                 {
1443                     ConstantInt *constant_index = dyn_cast<ConstantInt>(*ii);
1444 
1445                     if (!constant_index)
1446                     {
1447                         lldb_private::Scalar I;
1448 
1449                         if (!frame.EvaluateValue(I, *ii, llvm_module))
1450                         {
1451                             if (log)
1452                                 log->Printf("Couldn't evaluate %s", PrintValue(*ii).c_str());
1453                             err.SetErrorToGenericError();
1454                             err.SetErrorString(bad_value_error);
1455                             return false;
1456                         }
1457 
1458                         if (log)
1459                             log->Printf("Evaluated constant index %s as %llu", PrintValue(*ii).c_str(), I.ULongLong(LLDB_INVALID_ADDRESS));
1460 
1461                         constant_index = cast<ConstantInt>(ConstantInt::get((*ii)->getType(), I.ULongLong(LLDB_INVALID_ADDRESS)));
1462                     }
1463 
1464                     const_indices.push_back(constant_index);
1465                 }
1466 
1467                 uint64_t offset = target_data.getIndexedOffset(pointer_type, const_indices);
1468 
1469                 lldb_private::Scalar Poffset = P + offset;
1470 
1471                 frame.AssignValue(inst, Poffset, llvm_module);
1472 
1473                 if (log)
1474                 {
1475                     log->Printf("Interpreted a GetElementPtrInst");
1476                     log->Printf("  P       : %s", frame.SummarizeValue(pointer_operand).c_str());
1477                     log->Printf("  Poffset : %s", frame.SummarizeValue(inst).c_str());
1478                 }
1479             }
1480             break;
1481         case Instruction::ICmp:
1482             {
1483                 const ICmpInst *icmp_inst = dyn_cast<ICmpInst>(inst);
1484 
1485                 if (!icmp_inst)
1486                 {
1487                     if (log)
1488                         log->Printf("getOpcode() returns ICmp, but instruction is not an ICmpInst");
1489                     err.SetErrorToGenericError();
1490                     err.SetErrorString(interpreter_internal_error);
1491                     return false;
1492                 }
1493 
1494                 CmpInst::Predicate predicate = icmp_inst->getPredicate();
1495 
1496                 Value *lhs = inst->getOperand(0);
1497                 Value *rhs = inst->getOperand(1);
1498 
1499                 lldb_private::Scalar L;
1500                 lldb_private::Scalar R;
1501 
1502                 if (!frame.EvaluateValue(L, lhs, llvm_module))
1503                 {
1504                     if (log)
1505                         log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
1506                     err.SetErrorToGenericError();
1507                     err.SetErrorString(bad_value_error);
1508                     return false;
1509                 }
1510 
1511                 if (!frame.EvaluateValue(R, rhs, llvm_module))
1512                 {
1513                     if (log)
1514                         log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
1515                     err.SetErrorToGenericError();
1516                     err.SetErrorString(bad_value_error);
1517                     return false;
1518                 }
1519 
1520                 lldb_private::Scalar result;
1521 
1522                 switch (predicate)
1523                 {
1524                 default:
1525                     return false;
1526                 case CmpInst::ICMP_EQ:
1527                     result = (L == R);
1528                     break;
1529                 case CmpInst::ICMP_NE:
1530                     result = (L != R);
1531                     break;
1532                 case CmpInst::ICMP_UGT:
1533                     result = (L.GetRawBits64(0) > R.GetRawBits64(0));
1534                     break;
1535                 case CmpInst::ICMP_UGE:
1536                     result = (L.GetRawBits64(0) >= R.GetRawBits64(0));
1537                     break;
1538                 case CmpInst::ICMP_ULT:
1539                     result = (L.GetRawBits64(0) < R.GetRawBits64(0));
1540                     break;
1541                 case CmpInst::ICMP_ULE:
1542                     result = (L.GetRawBits64(0) <= R.GetRawBits64(0));
1543                     break;
1544                 case CmpInst::ICMP_SGT:
1545                     result = (L > R);
1546                     break;
1547                 case CmpInst::ICMP_SGE:
1548                     result = (L >= R);
1549                     break;
1550                 case CmpInst::ICMP_SLT:
1551                     result = (L < R);
1552                     break;
1553                 case CmpInst::ICMP_SLE:
1554                     result = (L <= R);
1555                     break;
1556                 }
1557 
1558                 frame.AssignValue(inst, result, llvm_module);
1559 
1560                 if (log)
1561                 {
1562                     log->Printf("Interpreted an ICmpInst");
1563                     log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
1564                     log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
1565                     log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
1566                 }
1567             }
1568             break;
1569         case Instruction::IntToPtr:
1570             {
1571                 const IntToPtrInst *int_to_ptr_inst = dyn_cast<IntToPtrInst>(inst);
1572 
1573                 if (!int_to_ptr_inst)
1574                 {
1575                     if (log)
1576                         log->Printf("getOpcode() returns IntToPtr, but instruction is not an IntToPtrInst");
1577                     err.SetErrorToGenericError();
1578                     err.SetErrorString(interpreter_internal_error);
1579                     return false;
1580                 }
1581 
1582                 Value *src_operand = int_to_ptr_inst->getOperand(0);
1583 
1584                 lldb_private::Scalar I;
1585 
1586                 if (!frame.EvaluateValue(I, src_operand, llvm_module))
1587                 {
1588                     if (log)
1589                         log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
1590                     err.SetErrorToGenericError();
1591                     err.SetErrorString(bad_value_error);
1592                     return false;
1593                 }
1594 
1595                 frame.AssignValue(inst, I, llvm_module);
1596 
1597                 if (log)
1598                 {
1599                     log->Printf("Interpreted an IntToPtr");
1600                     log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1601                     log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1602                 }
1603             }
1604             break;
1605         case Instruction::PtrToInt:
1606             {
1607                 const PtrToIntInst *ptr_to_int_inst = dyn_cast<PtrToIntInst>(inst);
1608 
1609                 if (!ptr_to_int_inst)
1610                 {
1611                     if (log)
1612                         log->Printf("getOpcode() returns PtrToInt, but instruction is not an PtrToIntInst");
1613                     err.SetErrorToGenericError();
1614                     err.SetErrorString(interpreter_internal_error);
1615                     return false;
1616                 }
1617 
1618                 Value *src_operand = ptr_to_int_inst->getOperand(0);
1619 
1620                 lldb_private::Scalar I;
1621 
1622                 if (!frame.EvaluateValue(I, src_operand, llvm_module))
1623                 {
1624                     if (log)
1625                         log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
1626                     err.SetErrorToGenericError();
1627                     err.SetErrorString(bad_value_error);
1628                     return false;
1629                 }
1630 
1631                 frame.AssignValue(inst, I, llvm_module);
1632 
1633                 if (log)
1634                 {
1635                     log->Printf("Interpreted a PtrToInt");
1636                     log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1637                     log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1638                 }
1639             }
1640             break;
1641         case Instruction::Load:
1642             {
1643                 const LoadInst *load_inst = dyn_cast<LoadInst>(inst);
1644 
1645                 if (!load_inst)
1646                 {
1647                     if (log)
1648                         log->Printf("getOpcode() returns Load, but instruction is not a LoadInst");
1649                     err.SetErrorToGenericError();
1650                     err.SetErrorString(interpreter_internal_error);
1651                     return false;
1652                 }
1653 
1654                 // The semantics of Load are:
1655                 //   Create a region D that will contain the loaded data
1656                 //   Resolve the region P containing a pointer
1657                 //   Dereference P to get the region R that the data should be loaded from
1658                 //   Transfer a unit of type type(D) from R to D
1659 
1660                 const Value *pointer_operand = load_inst->getPointerOperand();
1661 
1662                 Type *pointer_ty = pointer_operand->getType();
1663                 PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1664                 if (!pointer_ptr_ty)
1665                 {
1666                     if (log)
1667                         log->Printf("getPointerOperand()->getType() is not a PointerType");
1668                     err.SetErrorToGenericError();
1669                     err.SetErrorString(interpreter_internal_error);
1670                     return false;
1671                 }
1672                 Type *target_ty = pointer_ptr_ty->getElementType();
1673 
1674                 Memory::Region D = frame.ResolveValue(load_inst, llvm_module);
1675                 Memory::Region P = frame.ResolveValue(pointer_operand, llvm_module);
1676 
1677                 if (D.IsInvalid())
1678                 {
1679                     if (log)
1680                         log->Printf("LoadInst's value doesn't resolve to anything");
1681                     err.SetErrorToGenericError();
1682                     err.SetErrorString(bad_value_error);
1683                     return false;
1684                 }
1685 
1686                 if (P.IsInvalid())
1687                 {
1688                     if (log)
1689                         log->Printf("LoadInst's pointer doesn't resolve to anything");
1690                     err.SetErrorToGenericError();
1691                     err.SetErrorString(bad_value_error);
1692                     return false;
1693                 }
1694 
1695                 DataExtractorSP P_extractor(memory.GetExtractor(P));
1696                 DataEncoderSP D_encoder(memory.GetEncoder(D));
1697 
1698                 lldb::offset_t offset = 0;
1699                 lldb::addr_t pointer = P_extractor->GetAddress(&offset);
1700 
1701                 Memory::Region R = memory.Lookup(pointer, target_ty);
1702 
1703                 if (R.IsValid())
1704                 {
1705                     if (!memory.Read(D_encoder->GetDataStart(), R.m_base, target_data.getTypeStoreSize(target_ty)))
1706                     {
1707                         if (log)
1708                             log->Printf("Couldn't read from a region on behalf of a LoadInst");
1709                         err.SetErrorToGenericError();
1710                         err.SetErrorString(memory_read_error);
1711                         return false;
1712                     }
1713                 }
1714                 else
1715                 {
1716                     if (!memory.ReadFromRawPtr(D_encoder->GetDataStart(), pointer, target_data.getTypeStoreSize(target_ty)))
1717                     {
1718                         if (log)
1719                             log->Printf("Couldn't read from a raw pointer on behalf of a LoadInst");
1720                         err.SetErrorToGenericError();
1721                         err.SetErrorString(memory_read_error);
1722                         return false;
1723                     }
1724                 }
1725 
1726                 if (log)
1727                 {
1728                     log->Printf("Interpreted a LoadInst");
1729                     log->Printf("  P : %s", frame.SummarizeValue(pointer_operand).c_str());
1730                     if (R.IsValid())
1731                         log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1732                     else
1733                         log->Printf("  R : raw pointer 0x%llx", (unsigned long long)pointer);
1734                     log->Printf("  D : %s", frame.SummarizeValue(load_inst).c_str());
1735                 }
1736             }
1737             break;
1738         case Instruction::Ret:
1739             {
1740                 if (result_name.IsEmpty())
1741                     return true;
1742 
1743                 GlobalValue *result_value = llvm_module.getNamedValue(result_name.GetCString());
1744 
1745                 if (!frame.ConstructResult(result, result_value, result_name, result_type, llvm_module))
1746                 {
1747                     if (log)
1748                         log->Printf("Couldn't construct the expression's result");
1749                     err.SetErrorToGenericError();
1750                     err.SetErrorString(bad_result_error);
1751                     return false;
1752                 }
1753 
1754                 return true;
1755             }
1756         case Instruction::Store:
1757             {
1758                 const StoreInst *store_inst = dyn_cast<StoreInst>(inst);
1759 
1760                 if (!store_inst)
1761                 {
1762                     if (log)
1763                         log->Printf("getOpcode() returns Store, but instruction is not a StoreInst");
1764                     err.SetErrorToGenericError();
1765                     err.SetErrorString(interpreter_internal_error);
1766                     return false;
1767                 }
1768 
1769                 // The semantics of Store are:
1770                 //   Resolve the region D containing the data to be stored
1771                 //   Resolve the region P containing a pointer
1772                 //   Dereference P to get the region R that the data should be stored in
1773                 //   Transfer a unit of type type(D) from D to R
1774 
1775                 const Value *value_operand = store_inst->getValueOperand();
1776                 const Value *pointer_operand = store_inst->getPointerOperand();
1777 
1778                 Type *pointer_ty = pointer_operand->getType();
1779                 PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1780                 if (!pointer_ptr_ty)
1781                     return false;
1782                 Type *target_ty = pointer_ptr_ty->getElementType();
1783 
1784                 Memory::Region D = frame.ResolveValue(value_operand, llvm_module);
1785                 Memory::Region P = frame.ResolveValue(pointer_operand, llvm_module);
1786 
1787                 if (D.IsInvalid())
1788                 {
1789                     if (log)
1790                         log->Printf("StoreInst's value doesn't resolve to anything");
1791                     err.SetErrorToGenericError();
1792                     err.SetErrorString(bad_value_error);
1793                     return false;
1794                 }
1795 
1796                 if (P.IsInvalid())
1797                 {
1798                     if (log)
1799                         log->Printf("StoreInst's pointer doesn't resolve to anything");
1800                     err.SetErrorToGenericError();
1801                     err.SetErrorString(bad_value_error);
1802                     return false;
1803                 }
1804 
1805                 DataExtractorSP P_extractor(memory.GetExtractor(P));
1806                 DataExtractorSP D_extractor(memory.GetExtractor(D));
1807 
1808                 if (!P_extractor || !D_extractor)
1809                     return false;
1810 
1811                 lldb::offset_t offset = 0;
1812                 lldb::addr_t pointer = P_extractor->GetAddress(&offset);
1813 
1814                 Memory::Region R = memory.Lookup(pointer, target_ty);
1815 
1816                 if (R.IsValid())
1817                 {
1818                     if (!memory.Write(R.m_base, D_extractor->GetDataStart(), target_data.getTypeStoreSize(target_ty)))
1819                     {
1820                         if (log)
1821                             log->Printf("Couldn't write to a region on behalf of a LoadInst");
1822                         err.SetErrorToGenericError();
1823                         err.SetErrorString(memory_write_error);
1824                         return false;
1825                     }
1826                 }
1827                 else
1828                 {
1829                     if (!memory.WriteToRawPtr(pointer, D_extractor->GetDataStart(), target_data.getTypeStoreSize(target_ty)))
1830                     {
1831                         if (log)
1832                             log->Printf("Couldn't write to a raw pointer on behalf of a LoadInst");
1833                         err.SetErrorToGenericError();
1834                         err.SetErrorString(memory_write_error);
1835                         return false;
1836                     }
1837                 }
1838 
1839 
1840                 if (log)
1841                 {
1842                     log->Printf("Interpreted a StoreInst");
1843                     log->Printf("  D : %s", frame.SummarizeValue(value_operand).c_str());
1844                     log->Printf("  P : %s", frame.SummarizeValue(pointer_operand).c_str());
1845                     log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1846                 }
1847             }
1848             break;
1849         }
1850 
1851         ++frame.m_ii;
1852     }
1853 
1854     if (num_insts >= 4096)
1855     {
1856         err.SetErrorToGenericError();
1857         err.SetErrorString(infinite_loop_error);
1858         return false;
1859     }
1860 
1861     return false;
1862 }
1863