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/Constants.h"
19 #include "llvm/Function.h"
20 #include "llvm/Instructions.h"
21 #include "llvm/Module.h"
22 #include "llvm/Support/raw_ostream.h"
23 #include "llvm/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     m_error_stream(error_stream)
33 {
34 
35 }
36 
37 IRInterpreter::~IRInterpreter()
38 {
39 
40 }
41 
42 static std::string
43 PrintValue(const Value *value, bool truncate = false)
44 {
45     std::string s;
46     raw_string_ostream rso(s);
47     value->print(rso);
48     rso.flush();
49     if (truncate)
50         s.resize(s.length() - 1);
51 
52     size_t offset;
53     while ((offset = s.find('\n')) != s.npos)
54         s.erase(offset, 1);
55     while (s[0] == ' ' || s[0] == '\t')
56         s.erase(0, 1);
57 
58     return s;
59 }
60 
61 static std::string
62 PrintType(const Type *type, bool truncate = false)
63 {
64     std::string s;
65     raw_string_ostream rso(s);
66     type->print(rso);
67     rso.flush();
68     if (truncate)
69         s.resize(s.length() - 1);
70     return s;
71 }
72 
73 typedef STD_SHARED_PTR(lldb_private::DataEncoder) DataEncoderSP;
74 typedef STD_SHARED_PTR(lldb_private::DataExtractor) DataExtractorSP;
75 
76 class Memory
77 {
78 public:
79     typedef uint32_t                    index_t;
80 
81     struct Allocation
82     {
83         // m_virtual_address is always the address of the variable in the virtual memory
84         // space provided by Memory.
85         //
86         // m_origin is always non-NULL and describes the source of the data (possibly
87         // m_data if this allocation is the authoritative source).
88         //
89         // Possible value configurations:
90         //
91         // Allocation type  getValueType()          getContextType()            m_origin->GetScalar()       m_data
92         // =========================================================================================================================
93         // FileAddress      eValueTypeFileAddress   eContextTypeInvalid         A location in a binary      NULL
94         //                                                                      image
95         //
96         // LoadAddress      eValueTypeLoadAddress   eContextTypeInvalid         A location in the target's  NULL
97         //                                                                      virtual memory
98         //
99         // Alloca           eValueTypeHostAddress   eContextTypeInvalid         == m_data->GetBytes()       Deleted at end of
100         //                                                                                                  execution
101         //
102         // PersistentVar    eValueTypeHostAddress   eContextTypeClangType       A persistent variable's     NULL
103         //                                                                      location in LLDB's memory
104         //
105         // Register         [ignored]               eContextTypeRegister        [ignored]                   Flushed to the register
106         //                                                                                                  at the end of execution
107 
108         lldb::addr_t        m_virtual_address;
109         size_t              m_extent;
110         lldb_private::Value m_origin;
111         lldb::DataBufferSP  m_data;
112 
113         Allocation (lldb::addr_t virtual_address,
114                     size_t extent,
115                     lldb::DataBufferSP data) :
116             m_virtual_address(virtual_address),
117             m_extent(extent),
118             m_data(data)
119         {
120         }
121 
122         Allocation (const Allocation &allocation) :
123             m_virtual_address(allocation.m_virtual_address),
124             m_extent(allocation.m_extent),
125             m_origin(allocation.m_origin),
126             m_data(allocation.m_data)
127         {
128         }
129     };
130 
131     typedef STD_SHARED_PTR(Allocation)  AllocationSP;
132 
133     struct Region
134     {
135         AllocationSP m_allocation;
136         uint64_t m_base;
137         uint64_t m_extent;
138 
139         Region () :
140             m_allocation(),
141             m_base(0),
142             m_extent(0)
143         {
144         }
145 
146         Region (AllocationSP allocation, uint64_t base, uint64_t extent) :
147             m_allocation(allocation),
148             m_base(base),
149             m_extent(extent)
150         {
151         }
152 
153         Region (const Region &region) :
154             m_allocation(region.m_allocation),
155             m_base(region.m_base),
156             m_extent(region.m_extent)
157         {
158         }
159 
160         bool IsValid ()
161         {
162             return (bool) m_allocation;
163         }
164 
165         bool IsInvalid ()
166         {
167             return !m_allocation;
168         }
169     };
170 
171     typedef std::vector <AllocationSP>          MemoryMap;
172 
173 private:
174     lldb::addr_t        m_addr_base;
175     lldb::addr_t        m_addr_max;
176     MemoryMap           m_memory;
177     lldb::ByteOrder     m_byte_order;
178     lldb::addr_t        m_addr_byte_size;
179     DataLayout         &m_target_data;
180 
181     lldb_private::ClangExpressionDeclMap   &m_decl_map;
182 
183     MemoryMap::iterator LookupInternal (lldb::addr_t addr)
184     {
185         for (MemoryMap::iterator i = m_memory.begin(), e = m_memory.end();
186              i != e;
187              ++i)
188         {
189             if ((*i)->m_virtual_address <= addr &&
190                 (*i)->m_virtual_address + (*i)->m_extent > addr)
191                 return i;
192         }
193 
194         return m_memory.end();
195     }
196 
197 public:
198     Memory (DataLayout &target_data,
199             lldb_private::ClangExpressionDeclMap &decl_map,
200             lldb::addr_t alloc_start,
201             lldb::addr_t alloc_max) :
202         m_addr_base(alloc_start),
203         m_addr_max(alloc_max),
204         m_target_data(target_data),
205         m_decl_map(decl_map)
206     {
207         m_byte_order = (target_data.isLittleEndian() ? lldb::eByteOrderLittle : lldb::eByteOrderBig);
208         m_addr_byte_size = (target_data.getPointerSize(0));
209     }
210 
211     Region Malloc (size_t size, size_t align)
212     {
213         lldb::DataBufferSP data(new lldb_private::DataBufferHeap(size, 0));
214 
215         if (data)
216         {
217             index_t index = m_memory.size();
218 
219             const size_t mask = (align - 1);
220 
221             m_addr_base += mask;
222             m_addr_base &= ~mask;
223 
224             if (m_addr_base + size < m_addr_base ||
225                 m_addr_base + size > m_addr_max)
226                 return Region();
227 
228             uint64_t base = m_addr_base;
229 
230             m_memory.push_back(AllocationSP(new Allocation(base, size, data)));
231 
232             m_addr_base += size;
233 
234             AllocationSP alloc = m_memory[index];
235 
236             alloc->m_origin.GetScalar() = (unsigned long long)data->GetBytes();
237             alloc->m_origin.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
238             alloc->m_origin.SetValueType(lldb_private::Value::eValueTypeHostAddress);
239 
240             return Region(alloc, base, size);
241         }
242 
243         return Region();
244     }
245 
246     Region Malloc (Type *type)
247     {
248         return Malloc (m_target_data.getTypeAllocSize(type),
249                        m_target_data.getPrefTypeAlignment(type));
250     }
251 
252     Region Place (Type *type, lldb::addr_t base, lldb_private::Value &value)
253     {
254         index_t index = m_memory.size();
255         size_t size = m_target_data.getTypeAllocSize(type);
256 
257         m_memory.push_back(AllocationSP(new Allocation(base, size, lldb::DataBufferSP())));
258 
259         AllocationSP alloc = m_memory[index];
260 
261         alloc->m_origin = value;
262 
263         return Region(alloc, base, size);
264     }
265 
266     void Free (lldb::addr_t addr)
267     {
268         MemoryMap::iterator i = LookupInternal (addr);
269 
270         if (i != m_memory.end())
271             m_memory.erase(i);
272     }
273 
274     Region Lookup (lldb::addr_t addr, Type *type)
275     {
276         MemoryMap::iterator i = LookupInternal(addr);
277 
278         if (i == m_memory.end() || !type->isSized())
279             return Region();
280 
281         size_t size = m_target_data.getTypeStoreSize(type);
282 
283         return Region(*i, addr, size);
284     }
285 
286     DataEncoderSP GetEncoder (Region region)
287     {
288         if (region.m_allocation->m_origin.GetValueType() != lldb_private::Value::eValueTypeHostAddress)
289             return DataEncoderSP();
290 
291         lldb::DataBufferSP buffer = region.m_allocation->m_data;
292 
293         if (!buffer)
294             return DataEncoderSP();
295 
296         size_t base_offset = (size_t)(region.m_base - region.m_allocation->m_virtual_address);
297 
298         return DataEncoderSP(new lldb_private::DataEncoder(buffer->GetBytes() + base_offset, region.m_extent, m_byte_order, m_addr_byte_size));
299     }
300 
301     DataExtractorSP GetExtractor (Region region)
302     {
303         if (region.m_allocation->m_origin.GetValueType() != lldb_private::Value::eValueTypeHostAddress)
304             return DataExtractorSP();
305 
306         lldb::DataBufferSP buffer = region.m_allocation->m_data;
307         size_t base_offset = (size_t)(region.m_base - region.m_allocation->m_virtual_address);
308 
309         if (buffer)
310             return DataExtractorSP(new lldb_private::DataExtractor(buffer->GetBytes() + base_offset, region.m_extent, m_byte_order, m_addr_byte_size));
311         else
312             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));
313     }
314 
315     lldb_private::Value GetAccessTarget(lldb::addr_t addr)
316     {
317         MemoryMap::iterator i = LookupInternal(addr);
318 
319         if (i == m_memory.end())
320             return lldb_private::Value();
321 
322         lldb_private::Value target = (*i)->m_origin;
323 
324         if (target.GetContextType() == lldb_private::Value::eContextTypeRegisterInfo)
325         {
326             target.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
327             target.SetValueType(lldb_private::Value::eValueTypeHostAddress);
328             target.GetScalar() = (unsigned long long)(*i)->m_data->GetBytes();
329         }
330 
331         target.GetScalar() += (addr - (*i)->m_virtual_address);
332 
333         return target;
334     }
335 
336     bool Write (lldb::addr_t addr, const uint8_t *data, size_t length)
337     {
338         lldb_private::Value target = GetAccessTarget(addr);
339 
340         return m_decl_map.WriteTarget(target, data, length);
341     }
342 
343     bool Read (uint8_t *data, lldb::addr_t addr, size_t length)
344     {
345         lldb_private::Value source = GetAccessTarget(addr);
346 
347         return m_decl_map.ReadTarget(data, source, length);
348     }
349 
350     bool WriteToRawPtr (lldb::addr_t addr, const uint8_t *data, size_t length)
351     {
352         lldb_private::Value target = m_decl_map.WrapBareAddress(addr);
353 
354         return m_decl_map.WriteTarget(target, data, length);
355     }
356 
357     bool ReadFromRawPtr (uint8_t *data, lldb::addr_t addr, size_t length)
358     {
359         lldb_private::Value source = m_decl_map.WrapBareAddress(addr);
360 
361         return m_decl_map.ReadTarget(data, source, length);
362     }
363 
364     std::string PrintData (lldb::addr_t addr, size_t length)
365     {
366         lldb_private::Value target = GetAccessTarget(addr);
367 
368         lldb_private::DataBufferHeap buf(length, 0);
369 
370         if (!m_decl_map.ReadTarget(buf.GetBytes(), target, length))
371             return std::string("<couldn't read data>");
372 
373         lldb_private::StreamString ss;
374 
375         for (size_t i = 0; i < length; i++)
376         {
377             if ((!(i & 0xf)) && i)
378                 ss.Printf("%02hhx - ", buf.GetBytes()[i]);
379             else
380                 ss.Printf("%02hhx ", buf.GetBytes()[i]);
381         }
382 
383         return ss.GetString();
384     }
385 
386     std::string SummarizeRegion (Region &region)
387     {
388         lldb_private::StreamString ss;
389 
390         lldb_private::Value base = GetAccessTarget(region.m_base);
391 
392         ss.Printf("%llx [%s - %s %llx]",
393                   region.m_base,
394                   lldb_private::Value::GetValueTypeAsCString(base.GetValueType()),
395                   lldb_private::Value::GetContextTypeAsCString(base.GetContextType()),
396                   base.GetScalar().ULongLong());
397 
398         ss.Printf(" %s", PrintData(region.m_base, region.m_extent).c_str());
399 
400         return ss.GetString();
401     }
402 };
403 
404 class InterpreterStackFrame
405 {
406 public:
407     typedef std::map <const Value*, Memory::Region> ValueMap;
408 
409     ValueMap                                m_values;
410     Memory                                 &m_memory;
411     DataLayout                             &m_target_data;
412     lldb_private::ClangExpressionDeclMap   &m_decl_map;
413     const BasicBlock                       *m_bb;
414     BasicBlock::const_iterator              m_ii;
415     BasicBlock::const_iterator              m_ie;
416 
417     lldb::ByteOrder                         m_byte_order;
418     size_t                                  m_addr_byte_size;
419 
420     InterpreterStackFrame (DataLayout &target_data,
421                            Memory &memory,
422                            lldb_private::ClangExpressionDeclMap &decl_map) :
423         m_memory (memory),
424         m_target_data (target_data),
425         m_decl_map (decl_map)
426     {
427         m_byte_order = (target_data.isLittleEndian() ? lldb::eByteOrderLittle : lldb::eByteOrderBig);
428         m_addr_byte_size = (target_data.getPointerSize(0));
429     }
430 
431     void Jump (const BasicBlock *bb)
432     {
433         m_bb = bb;
434         m_ii = m_bb->begin();
435         m_ie = m_bb->end();
436     }
437 
438     bool Cache (Memory::AllocationSP allocation, Type *type)
439     {
440         if (allocation->m_origin.GetContextType() != lldb_private::Value::eContextTypeRegisterInfo)
441             return false;
442 
443         return m_decl_map.ReadTarget(allocation->m_data->GetBytes(), allocation->m_origin, allocation->m_data->GetByteSize());
444     }
445 
446     std::string SummarizeValue (const Value *value)
447     {
448         lldb_private::StreamString ss;
449 
450         ss.Printf("%s", PrintValue(value).c_str());
451 
452         ValueMap::iterator i = m_values.find(value);
453 
454         if (i != m_values.end())
455         {
456             Memory::Region region = i->second;
457 
458             ss.Printf(" %s", m_memory.SummarizeRegion(region).c_str());
459         }
460 
461         return ss.GetString();
462     }
463 
464     bool AssignToMatchType (lldb_private::Scalar &scalar, uint64_t u64value, Type *type)
465     {
466         size_t type_size = m_target_data.getTypeStoreSize(type);
467 
468         switch (type_size)
469         {
470         case 1:
471             scalar = (uint8_t)u64value;
472             break;
473         case 2:
474             scalar = (uint16_t)u64value;
475             break;
476         case 4:
477             scalar = (uint32_t)u64value;
478             break;
479         case 8:
480             scalar = (uint64_t)u64value;
481             break;
482         default:
483             return false;
484         }
485 
486         return true;
487     }
488 
489     bool EvaluateValue (lldb_private::Scalar &scalar, const Value *value, Module &module)
490     {
491         const Constant *constant = dyn_cast<Constant>(value);
492 
493         if (constant)
494         {
495             if (const ConstantInt *constant_int = dyn_cast<ConstantInt>(constant))
496             {
497                 return AssignToMatchType(scalar, constant_int->getLimitedValue(), value->getType());
498             }
499         }
500         else
501         {
502             Memory::Region region = ResolveValue(value, module);
503             DataExtractorSP value_extractor = m_memory.GetExtractor(region);
504 
505             if (!value_extractor)
506                 return false;
507 
508             size_t value_size = m_target_data.getTypeStoreSize(value->getType());
509 
510             uint32_t offset = 0;
511             uint64_t u64value = value_extractor->GetMaxU64(&offset, value_size);
512 
513             return AssignToMatchType(scalar, u64value, value->getType());
514         }
515 
516         return false;
517     }
518 
519     bool AssignValue (const Value *value, lldb_private::Scalar &scalar, Module &module)
520     {
521         Memory::Region region = ResolveValue (value, module);
522 
523         lldb_private::Scalar cast_scalar;
524 
525         if (!AssignToMatchType(cast_scalar, scalar.GetRawBits64(0), value->getType()))
526             return false;
527 
528         lldb_private::DataBufferHeap buf(cast_scalar.GetByteSize(), 0);
529 
530         lldb_private::Error err;
531 
532         if (!cast_scalar.GetAsMemoryData(buf.GetBytes(), buf.GetByteSize(), m_byte_order, err))
533             return false;
534 
535         DataEncoderSP region_encoder = m_memory.GetEncoder(region);
536 
537         memcpy(region_encoder->GetDataStart(), buf.GetBytes(), buf.GetByteSize());
538 
539         return true;
540     }
541 
542     bool ResolveConstantValue (APInt &value, const Constant *constant)
543     {
544         if (const ConstantInt *constant_int = dyn_cast<ConstantInt>(constant))
545         {
546             value = constant_int->getValue();
547             return true;
548         }
549         else if (const ConstantFP *constant_fp = dyn_cast<ConstantFP>(constant))
550         {
551             value = constant_fp->getValueAPF().bitcastToAPInt();
552             return true;
553         }
554         else if (const ConstantExpr *constant_expr = dyn_cast<ConstantExpr>(constant))
555         {
556             switch (constant_expr->getOpcode())
557             {
558                 default:
559                     return false;
560                 case Instruction::IntToPtr:
561                 case Instruction::BitCast:
562                     return ResolveConstantValue(value, constant_expr->getOperand(0));
563                 case Instruction::GetElementPtr:
564                 {
565                     ConstantExpr::const_op_iterator op_cursor = constant_expr->op_begin();
566                     ConstantExpr::const_op_iterator op_end = constant_expr->op_end();
567 
568                     Constant *base = dyn_cast<Constant>(*op_cursor);
569 
570                     if (!base)
571                         return false;
572 
573                     if (!ResolveConstantValue(value, base))
574                         return false;
575 
576                     op_cursor++;
577 
578                     if (op_cursor == op_end)
579                         return true; // no offset to apply!
580 
581                     SmallVector <Value *, 8> indices (op_cursor, op_end);
582 
583                     uint64_t offset = m_target_data.getIndexedOffset(base->getType(), indices);
584 
585                     const bool is_signed = true;
586                     value += APInt(value.getBitWidth(), offset, is_signed);
587 
588                     return true;
589                 }
590             }
591         }
592 
593         return false;
594     }
595 
596     bool ResolveConstant (Memory::Region &region, const Constant *constant)
597     {
598         APInt resolved_value;
599 
600         if (!ResolveConstantValue(resolved_value, constant))
601             return false;
602 
603         const uint64_t *raw_data = resolved_value.getRawData();
604 
605         size_t constant_size = m_target_data.getTypeStoreSize(constant->getType());
606         return m_memory.Write(region.m_base, (const uint8_t*)raw_data, constant_size);
607     }
608 
609     Memory::Region ResolveValue (const Value *value, Module &module)
610     {
611         ValueMap::iterator i = m_values.find(value);
612 
613         if (i != m_values.end())
614             return i->second;
615 
616         const GlobalValue *global_value = dyn_cast<GlobalValue>(value);
617 
618         // If the variable is indirected through the argument
619         // array then we need to build an extra level of indirection
620         // for it.  This is the default; only magic arguments like
621         // "this", "self", and "_cmd" are direct.
622         bool indirect_variable = true;
623 
624         // Attempt to resolve the value using the program's data.
625         // If it is, the values to be created are:
626         //
627         // data_region - a region of memory in which the variable's data resides.
628         // ref_region - a region of memory in which its address (i.e., &var) resides.
629         //   In the JIT case, this region would be a member of the struct passed in.
630         // pointer_region - a region of memory in which the address of the pointer
631         //   resides.  This is an IR-level variable.
632         do
633         {
634             lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
635 
636             lldb_private::Value resolved_value;
637             lldb_private::ClangExpressionVariable::FlagType flags = 0;
638 
639             if (global_value)
640             {
641                 clang::NamedDecl *decl = IRForTarget::DeclForGlobal(global_value, &module);
642 
643                 if (!decl)
644                     break;
645 
646                 if (isa<clang::FunctionDecl>(decl))
647                 {
648                     if (log)
649                         log->Printf("The interpreter does not handle function pointers at the moment");
650 
651                     return Memory::Region();
652                 }
653 
654                 resolved_value = m_decl_map.LookupDecl(decl, flags);
655             }
656             else
657             {
658                 // Special-case "this", "self", and "_cmd"
659 
660                 std::string name_str = value->getName().str();
661 
662                 if (name_str == "this" ||
663                     name_str == "self" ||
664                     name_str == "_cmd")
665                     resolved_value = m_decl_map.GetSpecialValue(lldb_private::ConstString(name_str.c_str()));
666 
667                 indirect_variable = false;
668             }
669 
670             if (resolved_value.GetScalar().GetType() != lldb_private::Scalar::e_void)
671             {
672                 if (resolved_value.GetContextType() == lldb_private::Value::eContextTypeRegisterInfo)
673                 {
674                     bool bare_register = (flags & lldb_private::ClangExpressionVariable::EVBareRegister);
675 
676                     if (bare_register)
677                         indirect_variable = false;
678 
679                     lldb_private::RegisterInfo *reg_info = resolved_value.GetRegisterInfo();
680                     Memory::Region data_region = (reg_info->encoding == lldb::eEncodingVector) ?
681                         m_memory.Malloc(reg_info->byte_size, m_target_data.getPrefTypeAlignment(value->getType())) :
682                         m_memory.Malloc(value->getType());
683 
684                     data_region.m_allocation->m_origin = 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 (!Cache(data_region.m_allocation, value->getType()))
692                         return Memory::Region();
693 
694                     if (ref_region.IsInvalid())
695                         return Memory::Region();
696 
697                     if (pointer_region.IsInvalid() && indirect_variable)
698                         return Memory::Region();
699 
700                     DataEncoderSP ref_encoder = m_memory.GetEncoder(ref_region);
701 
702                     if (ref_encoder->PutAddress(0, data_region.m_base) == UINT32_MAX)
703                         return Memory::Region();
704 
705                     if (log)
706                     {
707                         log->Printf("Made an allocation for register variable %s", PrintValue(value).c_str());
708                         log->Printf("  Data contents  : %s", m_memory.PrintData(data_region.m_base, data_region.m_extent).c_str());
709                         log->Printf("  Data region    : %llx", (unsigned long long)data_region.m_base);
710                         log->Printf("  Ref region     : %llx", (unsigned long long)ref_region.m_base);
711                         if (indirect_variable)
712                             log->Printf("  Pointer region : %llx", (unsigned long long)pointer_region.m_base);
713                     }
714 
715                     if (indirect_variable)
716                     {
717                         DataEncoderSP pointer_encoder = m_memory.GetEncoder(pointer_region);
718 
719                         if (pointer_encoder->PutAddress(0, ref_region.m_base) == UINT32_MAX)
720                             return Memory::Region();
721 
722                         m_values[value] = pointer_region;
723                         return pointer_region;
724                     }
725                     else
726                     {
727                         m_values[value] = ref_region;
728                         return ref_region;
729                     }
730                 }
731                 else
732                 {
733                     Memory::Region data_region = m_memory.Place(value->getType(), resolved_value.GetScalar().ULongLong(), resolved_value);
734                     Memory::Region ref_region = m_memory.Malloc(value->getType());
735                     Memory::Region pointer_region;
736 
737                     if (indirect_variable)
738                         pointer_region = m_memory.Malloc(value->getType());
739 
740                     if (ref_region.IsInvalid())
741                         return Memory::Region();
742 
743                     if (pointer_region.IsInvalid() && indirect_variable)
744                         return Memory::Region();
745 
746                     DataEncoderSP ref_encoder = m_memory.GetEncoder(ref_region);
747 
748                     if (ref_encoder->PutAddress(0, data_region.m_base) == UINT32_MAX)
749                         return Memory::Region();
750 
751                     if (indirect_variable)
752                     {
753                         DataEncoderSP pointer_encoder = m_memory.GetEncoder(pointer_region);
754 
755                         if (pointer_encoder->PutAddress(0, ref_region.m_base) == UINT32_MAX)
756                             return Memory::Region();
757 
758                         m_values[value] = pointer_region;
759                     }
760 
761                     if (log)
762                     {
763                         log->Printf("Made an allocation for %s", PrintValue(value).c_str());
764                         log->Printf("  Data contents  : %s", m_memory.PrintData(data_region.m_base, data_region.m_extent).c_str());
765                         log->Printf("  Data region    : %llx", (unsigned long long)data_region.m_base);
766                         log->Printf("  Ref region     : %llx", (unsigned long long)ref_region.m_base);
767                         if (indirect_variable)
768                             log->Printf("  Pointer region : %llx", (unsigned long long)pointer_region.m_base);
769                     }
770 
771                     if (indirect_variable)
772                         return pointer_region;
773                     else
774                         return ref_region;
775                 }
776             }
777         }
778         while(0);
779 
780         // Fall back and allocate space [allocation type Alloca]
781 
782         Type *type = value->getType();
783 
784         lldb::ValueSP backing_value(new lldb_private::Value);
785 
786         Memory::Region data_region = m_memory.Malloc(type);
787         data_region.m_allocation->m_origin.GetScalar() = (unsigned long long)data_region.m_allocation->m_data->GetBytes();
788         data_region.m_allocation->m_origin.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
789         data_region.m_allocation->m_origin.SetValueType(lldb_private::Value::eValueTypeHostAddress);
790 
791         const Constant *constant = dyn_cast<Constant>(value);
792 
793         do
794         {
795             if (!constant)
796                 break;
797 
798             if (!ResolveConstant (data_region, constant))
799                 return Memory::Region();
800         }
801         while(0);
802 
803         m_values[value] = data_region;
804         return data_region;
805     }
806 
807     bool ConstructResult (lldb::ClangExpressionVariableSP &result,
808                           const GlobalValue *result_value,
809                           const lldb_private::ConstString &result_name,
810                           lldb_private::TypeFromParser result_type,
811                           Module &module)
812     {
813         // The result_value resolves to P, a pointer to a region R containing the result data.
814         // If the result variable is a reference, the region R contains a pointer to the result R_final in the original process.
815 
816         if (!result_value)
817             return true; // There was no slot for a result – the expression doesn't return one.
818 
819         ValueMap::iterator i = m_values.find(result_value);
820 
821         if (i == m_values.end())
822             return false; // There was a slot for the result, but we didn't write into it.
823 
824         Memory::Region P = i->second;
825         DataExtractorSP P_extractor = m_memory.GetExtractor(P);
826 
827         if (!P_extractor)
828             return false;
829 
830         Type *pointer_ty = result_value->getType();
831         PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
832         if (!pointer_ptr_ty)
833             return false;
834         Type *R_ty = pointer_ptr_ty->getElementType();
835 
836         uint32_t offset = 0;
837         lldb::addr_t pointer = P_extractor->GetAddress(&offset);
838 
839         Memory::Region R = m_memory.Lookup(pointer, R_ty);
840 
841         if (R.m_allocation->m_origin.GetValueType() != lldb_private::Value::eValueTypeHostAddress ||
842             !R.m_allocation->m_data)
843             return false;
844 
845         lldb_private::Value base;
846 
847         bool transient = false;
848         bool maybe_make_load = false;
849 
850         if (m_decl_map.ResultIsReference(result_name))
851         {
852             PointerType *R_ptr_ty = dyn_cast<PointerType>(R_ty);
853             if (!R_ptr_ty)
854                 return false;
855             Type *R_final_ty = R_ptr_ty->getElementType();
856 
857             DataExtractorSP R_extractor = m_memory.GetExtractor(R);
858 
859             if (!R_extractor)
860                 return false;
861 
862             offset = 0;
863             lldb::addr_t R_pointer = R_extractor->GetAddress(&offset);
864 
865             Memory::Region R_final = m_memory.Lookup(R_pointer, R_final_ty);
866 
867             if (R_final.m_allocation)
868             {
869                 if (R_final.m_allocation->m_data)
870                     transient = true; // this is a stack allocation
871 
872                 base = R_final.m_allocation->m_origin;
873                 base.GetScalar() += (R_final.m_base - R_final.m_allocation->m_virtual_address);
874             }
875             else
876             {
877                 // We got a bare pointer.  We are going to treat it as a load address
878                 // or a file address, letting decl_map make the choice based on whether
879                 // or not a process exists.
880 
881                 base.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
882                 base.SetValueType(lldb_private::Value::eValueTypeFileAddress);
883                 base.GetScalar() = (unsigned long long)R_pointer;
884                 maybe_make_load = true;
885             }
886         }
887         else
888         {
889             base.SetContext(lldb_private::Value::eContextTypeInvalid, NULL);
890             base.SetValueType(lldb_private::Value::eValueTypeHostAddress);
891             base.GetScalar() = (unsigned long long)R.m_allocation->m_data->GetBytes() + (R.m_base - R.m_allocation->m_virtual_address);
892         }
893 
894         return m_decl_map.CompleteResultVariable (result, base, result_name, result_type, transient, maybe_make_load);
895     }
896 };
897 
898 bool
899 IRInterpreter::maybeRunOnFunction (lldb::ClangExpressionVariableSP &result,
900                                    const lldb_private::ConstString &result_name,
901                                    lldb_private::TypeFromParser result_type,
902                                    Function &llvm_function,
903                                    Module &llvm_module,
904                                    lldb_private::Error &err)
905 {
906     if (supportsFunction (llvm_function, err))
907         return runOnFunction(result,
908                              result_name,
909                              result_type,
910                              llvm_function,
911                              llvm_module,
912                              err);
913     else
914         return false;
915 }
916 
917 static const char *unsupported_opcode_error         = "Interpreter doesn't handle one of the expression's opcodes";
918 static const char *interpreter_initialization_error = "Interpreter couldn't be initialized";
919 static const char *interpreter_internal_error       = "Interpreter encountered an internal error";
920 static const char *bad_value_error                  = "Interpreter couldn't resolve a value during execution";
921 static const char *memory_allocation_error          = "Interpreter couldn't allocate memory";
922 static const char *memory_write_error               = "Interpreter couldn't write to memory";
923 static const char *memory_read_error                = "Interpreter couldn't read from memory";
924 static const char *infinite_loop_error              = "Interpreter ran for too many cycles";
925 static const char *bad_result_error                 = "Result of expression is in bad memory";
926 
927 bool
928 IRInterpreter::supportsFunction (Function &llvm_function,
929                                  lldb_private::Error &err)
930 {
931     lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
932 
933     for (Function::iterator bbi = llvm_function.begin(), bbe = llvm_function.end();
934          bbi != bbe;
935          ++bbi)
936     {
937         for (BasicBlock::iterator ii = bbi->begin(), ie = bbi->end();
938              ii != ie;
939              ++ii)
940         {
941             switch (ii->getOpcode())
942             {
943             default:
944                 {
945                     if (log)
946                         log->Printf("Unsupported instruction: %s", PrintValue(ii).c_str());
947                     err.SetErrorToGenericError();
948                     err.SetErrorString(unsupported_opcode_error);
949                     return false;
950                 }
951             case Instruction::Add:
952             case Instruction::Alloca:
953             case Instruction::BitCast:
954             case Instruction::Br:
955             case Instruction::GetElementPtr:
956                 break;
957             case Instruction::ICmp:
958                 {
959                     ICmpInst *icmp_inst = dyn_cast<ICmpInst>(ii);
960 
961                     if (!icmp_inst)
962                     {
963                         err.SetErrorToGenericError();
964                         err.SetErrorString(interpreter_internal_error);
965                         return false;
966                     }
967 
968                     switch (icmp_inst->getPredicate())
969                     {
970                     default:
971                         {
972                             if (log)
973                                 log->Printf("Unsupported ICmp predicate: %s", PrintValue(ii).c_str());
974 
975                             err.SetErrorToGenericError();
976                             err.SetErrorString(unsupported_opcode_error);
977                             return false;
978                         }
979                     case CmpInst::ICMP_EQ:
980                     case CmpInst::ICMP_NE:
981                     case CmpInst::ICMP_UGT:
982                     case CmpInst::ICMP_UGE:
983                     case CmpInst::ICMP_ULT:
984                     case CmpInst::ICMP_ULE:
985                     case CmpInst::ICMP_SGT:
986                     case CmpInst::ICMP_SGE:
987                     case CmpInst::ICMP_SLT:
988                     case CmpInst::ICMP_SLE:
989                         break;
990                     }
991                 }
992                 break;
993             case Instruction::IntToPtr:
994             case Instruction::Load:
995             case Instruction::Mul:
996             case Instruction::Ret:
997             case Instruction::SDiv:
998             case Instruction::Store:
999             case Instruction::Sub:
1000             case Instruction::UDiv:
1001             case Instruction::ZExt:
1002                 break;
1003             }
1004         }
1005     }
1006 
1007     return true;
1008 }
1009 
1010 bool
1011 IRInterpreter::runOnFunction (lldb::ClangExpressionVariableSP &result,
1012                               const lldb_private::ConstString &result_name,
1013                               lldb_private::TypeFromParser result_type,
1014                               Function &llvm_function,
1015                               Module &llvm_module,
1016                               lldb_private::Error &err)
1017 {
1018     lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
1019 
1020     lldb_private::ClangExpressionDeclMap::TargetInfo target_info = m_decl_map.GetTargetInfo();
1021 
1022     if (!target_info.IsValid())
1023     {
1024         err.SetErrorToGenericError();
1025         err.SetErrorString(interpreter_initialization_error);
1026         return false;
1027     }
1028 
1029     lldb::addr_t alloc_min;
1030     lldb::addr_t alloc_max;
1031 
1032     switch (target_info.address_byte_size)
1033     {
1034     default:
1035         err.SetErrorToGenericError();
1036         err.SetErrorString(interpreter_initialization_error);
1037         return false;
1038     case 4:
1039         alloc_min = 0x00001000llu;
1040         alloc_max = 0x0000ffffllu;
1041         break;
1042     case 8:
1043         alloc_min = 0x0000000000001000llu;
1044         alloc_max = 0x000000000000ffffllu;
1045         break;
1046     }
1047 
1048     DataLayout target_data(&llvm_module);
1049     if (target_data.getPointerSize(0) != target_info.address_byte_size)
1050     {
1051         err.SetErrorToGenericError();
1052         err.SetErrorString(interpreter_initialization_error);
1053         return false;
1054     }
1055     if (target_data.isLittleEndian() != (target_info.byte_order == lldb::eByteOrderLittle))
1056     {
1057         err.SetErrorToGenericError();
1058         err.SetErrorString(interpreter_initialization_error);
1059         return false;
1060     }
1061 
1062     Memory memory(target_data, m_decl_map, alloc_min, alloc_max);
1063     InterpreterStackFrame frame(target_data, memory, m_decl_map);
1064 
1065     uint32_t num_insts = 0;
1066 
1067     frame.Jump(llvm_function.begin());
1068 
1069     while (frame.m_ii != frame.m_ie && (++num_insts < 4096))
1070     {
1071         const Instruction *inst = frame.m_ii;
1072 
1073         if (log)
1074             log->Printf("Interpreting %s", PrintValue(inst).c_str());
1075 
1076         switch (inst->getOpcode())
1077         {
1078         default:
1079             break;
1080         case Instruction::Add:
1081         case Instruction::Sub:
1082         case Instruction::Mul:
1083         case Instruction::SDiv:
1084         case Instruction::UDiv:
1085             {
1086                 const BinaryOperator *bin_op = dyn_cast<BinaryOperator>(inst);
1087 
1088                 if (!bin_op)
1089                 {
1090                     if (log)
1091                         log->Printf("getOpcode() returns %s, but instruction is not a BinaryOperator", inst->getOpcodeName());
1092                     err.SetErrorToGenericError();
1093                     err.SetErrorString(interpreter_internal_error);
1094                     return false;
1095                 }
1096 
1097                 Value *lhs = inst->getOperand(0);
1098                 Value *rhs = inst->getOperand(1);
1099 
1100                 lldb_private::Scalar L;
1101                 lldb_private::Scalar R;
1102 
1103                 if (!frame.EvaluateValue(L, lhs, llvm_module))
1104                 {
1105                     if (log)
1106                         log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
1107                     err.SetErrorToGenericError();
1108                     err.SetErrorString(bad_value_error);
1109                     return false;
1110                 }
1111 
1112                 if (!frame.EvaluateValue(R, rhs, llvm_module))
1113                 {
1114                     if (log)
1115                         log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
1116                     err.SetErrorToGenericError();
1117                     err.SetErrorString(bad_value_error);
1118                     return false;
1119                 }
1120 
1121                 lldb_private::Scalar result;
1122 
1123                 switch (inst->getOpcode())
1124                 {
1125                 default:
1126                     break;
1127                 case Instruction::Add:
1128                     result = L + R;
1129                     break;
1130                 case Instruction::Mul:
1131                     result = L * R;
1132                     break;
1133                 case Instruction::Sub:
1134                     result = L - R;
1135                     break;
1136                 case Instruction::SDiv:
1137                     result = L / R;
1138                     break;
1139                 case Instruction::UDiv:
1140                     result = L.GetRawBits64(0) / R.GetRawBits64(1);
1141                     break;
1142                 }
1143 
1144                 frame.AssignValue(inst, result, llvm_module);
1145 
1146                 if (log)
1147                 {
1148                     log->Printf("Interpreted a %s", inst->getOpcodeName());
1149                     log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
1150                     log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
1151                     log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
1152                 }
1153             }
1154             break;
1155         case Instruction::Alloca:
1156             {
1157                 const AllocaInst *alloca_inst = dyn_cast<AllocaInst>(inst);
1158 
1159                 if (!alloca_inst)
1160                 {
1161                     if (log)
1162                         log->Printf("getOpcode() returns Alloca, but instruction is not an AllocaInst");
1163                     err.SetErrorToGenericError();
1164                     err.SetErrorString(interpreter_internal_error);
1165                     return false;
1166                 }
1167 
1168                 if (alloca_inst->isArrayAllocation())
1169                 {
1170                     if (log)
1171                         log->Printf("AllocaInsts are not handled if isArrayAllocation() is true");
1172                     err.SetErrorToGenericError();
1173                     err.SetErrorString(unsupported_opcode_error);
1174                     return false;
1175                 }
1176 
1177                 // The semantics of Alloca are:
1178                 //   Create a region R of virtual memory of type T, backed by a data buffer
1179                 //   Create a region P of virtual memory of type T*, backed by a data buffer
1180                 //   Write the virtual address of R into P
1181 
1182                 Type *T = alloca_inst->getAllocatedType();
1183                 Type *Tptr = alloca_inst->getType();
1184 
1185                 Memory::Region R = memory.Malloc(T);
1186 
1187                 if (R.IsInvalid())
1188                 {
1189                     if (log)
1190                         log->Printf("Couldn't allocate memory for an AllocaInst");
1191                     err.SetErrorToGenericError();
1192                     err.SetErrorString(memory_allocation_error);
1193                     return false;
1194                 }
1195 
1196                 Memory::Region P = memory.Malloc(Tptr);
1197 
1198                 if (P.IsInvalid())
1199                 {
1200                     if (log)
1201                         log->Printf("Couldn't allocate the result pointer for an AllocaInst");
1202                     err.SetErrorToGenericError();
1203                     err.SetErrorString(memory_allocation_error);
1204                     return false;
1205                 }
1206 
1207                 DataEncoderSP P_encoder = memory.GetEncoder(P);
1208 
1209                 if (P_encoder->PutAddress(0, R.m_base) == UINT32_MAX)
1210                 {
1211                     if (log)
1212                         log->Printf("Couldn't write the result pointer for an AllocaInst");
1213                     err.SetErrorToGenericError();
1214                     err.SetErrorString(memory_write_error);
1215                     return false;
1216                 }
1217 
1218                 frame.m_values[alloca_inst] = P;
1219 
1220                 if (log)
1221                 {
1222                     log->Printf("Interpreted an AllocaInst");
1223                     log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1224                     log->Printf("  P : %s", frame.SummarizeValue(alloca_inst).c_str());
1225                 }
1226             }
1227             break;
1228         case Instruction::BitCast:
1229         case Instruction::ZExt:
1230             {
1231                 const CastInst *cast_inst = dyn_cast<CastInst>(inst);
1232 
1233                 if (!cast_inst)
1234                 {
1235                     if (log)
1236                         log->Printf("getOpcode() returns %s, but instruction is not a BitCastInst", cast_inst->getOpcodeName());
1237                     err.SetErrorToGenericError();
1238                     err.SetErrorString(interpreter_internal_error);
1239                     return false;
1240                 }
1241 
1242                 Value *source = cast_inst->getOperand(0);
1243 
1244                 lldb_private::Scalar S;
1245 
1246                 if (!frame.EvaluateValue(S, source, llvm_module))
1247                 {
1248                     if (log)
1249                         log->Printf("Couldn't evaluate %s", PrintValue(source).c_str());
1250                     err.SetErrorToGenericError();
1251                     err.SetErrorString(bad_value_error);
1252                     return false;
1253                 }
1254 
1255                 frame.AssignValue(inst, S, llvm_module);
1256             }
1257             break;
1258         case Instruction::Br:
1259             {
1260                 const BranchInst *br_inst = dyn_cast<BranchInst>(inst);
1261 
1262                 if (!br_inst)
1263                 {
1264                     if (log)
1265                         log->Printf("getOpcode() returns Br, but instruction is not a BranchInst");
1266                     err.SetErrorToGenericError();
1267                     err.SetErrorString(interpreter_internal_error);
1268                     return false;
1269                 }
1270 
1271                 if (br_inst->isConditional())
1272                 {
1273                     Value *condition = br_inst->getCondition();
1274 
1275                     lldb_private::Scalar C;
1276 
1277                     if (!frame.EvaluateValue(C, condition, llvm_module))
1278                     {
1279                         if (log)
1280                             log->Printf("Couldn't evaluate %s", PrintValue(condition).c_str());
1281                         err.SetErrorToGenericError();
1282                         err.SetErrorString(bad_value_error);
1283                         return false;
1284                     }
1285 
1286                     if (C.GetRawBits64(0))
1287                         frame.Jump(br_inst->getSuccessor(0));
1288                     else
1289                         frame.Jump(br_inst->getSuccessor(1));
1290 
1291                     if (log)
1292                     {
1293                         log->Printf("Interpreted a BrInst with a condition");
1294                         log->Printf("  cond : %s", frame.SummarizeValue(condition).c_str());
1295                     }
1296                 }
1297                 else
1298                 {
1299                     frame.Jump(br_inst->getSuccessor(0));
1300 
1301                     if (log)
1302                     {
1303                         log->Printf("Interpreted a BrInst with no condition");
1304                     }
1305                 }
1306             }
1307             continue;
1308         case Instruction::GetElementPtr:
1309             {
1310                 const GetElementPtrInst *gep_inst = dyn_cast<GetElementPtrInst>(inst);
1311 
1312                 if (!gep_inst)
1313                 {
1314                     if (log)
1315                         log->Printf("getOpcode() returns GetElementPtr, but instruction is not a GetElementPtrInst");
1316                     err.SetErrorToGenericError();
1317                     err.SetErrorString(interpreter_internal_error);
1318                     return false;
1319                 }
1320 
1321                 const Value *pointer_operand = gep_inst->getPointerOperand();
1322                 Type *pointer_type = pointer_operand->getType();
1323 
1324                 lldb_private::Scalar P;
1325 
1326                 if (!frame.EvaluateValue(P, pointer_operand, llvm_module))
1327                 {
1328                     if (log)
1329                         log->Printf("Couldn't evaluate %s", PrintValue(pointer_operand).c_str());
1330                     err.SetErrorToGenericError();
1331                     err.SetErrorString(bad_value_error);
1332                     return false;
1333                 }
1334 
1335                 typedef SmallVector <Value *, 8> IndexVector;
1336                 typedef IndexVector::iterator IndexIterator;
1337 
1338                 SmallVector <Value *, 8> indices (gep_inst->idx_begin(),
1339                                                   gep_inst->idx_end());
1340 
1341                 SmallVector <Value *, 8> const_indices;
1342 
1343                 for (IndexIterator ii = indices.begin(), ie = indices.end();
1344                      ii != ie;
1345                      ++ii)
1346                 {
1347                     ConstantInt *constant_index = dyn_cast<ConstantInt>(*ii);
1348 
1349                     if (!constant_index)
1350                     {
1351                         lldb_private::Scalar I;
1352 
1353                         if (!frame.EvaluateValue(I, *ii, llvm_module))
1354                         {
1355                             if (log)
1356                                 log->Printf("Couldn't evaluate %s", PrintValue(*ii).c_str());
1357                             err.SetErrorToGenericError();
1358                             err.SetErrorString(bad_value_error);
1359                             return false;
1360                         }
1361 
1362                         if (log)
1363                             log->Printf("Evaluated constant index %s as %llu", PrintValue(*ii).c_str(), I.ULongLong(LLDB_INVALID_ADDRESS));
1364 
1365                         constant_index = cast<ConstantInt>(ConstantInt::get((*ii)->getType(), I.ULongLong(LLDB_INVALID_ADDRESS)));
1366                     }
1367 
1368                     const_indices.push_back(constant_index);
1369                 }
1370 
1371                 uint64_t offset = target_data.getIndexedOffset(pointer_type, const_indices);
1372 
1373                 lldb_private::Scalar Poffset = P + offset;
1374 
1375                 frame.AssignValue(inst, Poffset, llvm_module);
1376 
1377                 if (log)
1378                 {
1379                     log->Printf("Interpreted a GetElementPtrInst");
1380                     log->Printf("  P       : %s", frame.SummarizeValue(pointer_operand).c_str());
1381                     log->Printf("  Poffset : %s", frame.SummarizeValue(inst).c_str());
1382                 }
1383             }
1384             break;
1385         case Instruction::ICmp:
1386             {
1387                 const ICmpInst *icmp_inst = dyn_cast<ICmpInst>(inst);
1388 
1389                 if (!icmp_inst)
1390                 {
1391                     if (log)
1392                         log->Printf("getOpcode() returns ICmp, but instruction is not an ICmpInst");
1393                     err.SetErrorToGenericError();
1394                     err.SetErrorString(interpreter_internal_error);
1395                     return false;
1396                 }
1397 
1398                 CmpInst::Predicate predicate = icmp_inst->getPredicate();
1399 
1400                 Value *lhs = inst->getOperand(0);
1401                 Value *rhs = inst->getOperand(1);
1402 
1403                 lldb_private::Scalar L;
1404                 lldb_private::Scalar R;
1405 
1406                 if (!frame.EvaluateValue(L, lhs, llvm_module))
1407                 {
1408                     if (log)
1409                         log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
1410                     err.SetErrorToGenericError();
1411                     err.SetErrorString(bad_value_error);
1412                     return false;
1413                 }
1414 
1415                 if (!frame.EvaluateValue(R, rhs, llvm_module))
1416                 {
1417                     if (log)
1418                         log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
1419                     err.SetErrorToGenericError();
1420                     err.SetErrorString(bad_value_error);
1421                     return false;
1422                 }
1423 
1424                 lldb_private::Scalar result;
1425 
1426                 switch (predicate)
1427                 {
1428                 default:
1429                     return false;
1430                 case CmpInst::ICMP_EQ:
1431                     result = (L == R);
1432                     break;
1433                 case CmpInst::ICMP_NE:
1434                     result = (L != R);
1435                     break;
1436                 case CmpInst::ICMP_UGT:
1437                     result = (L.GetRawBits64(0) > R.GetRawBits64(0));
1438                     break;
1439                 case CmpInst::ICMP_UGE:
1440                     result = (L.GetRawBits64(0) >= R.GetRawBits64(0));
1441                     break;
1442                 case CmpInst::ICMP_ULT:
1443                     result = (L.GetRawBits64(0) < R.GetRawBits64(0));
1444                     break;
1445                 case CmpInst::ICMP_ULE:
1446                     result = (L.GetRawBits64(0) <= R.GetRawBits64(0));
1447                     break;
1448                 case CmpInst::ICMP_SGT:
1449                     result = (L > R);
1450                     break;
1451                 case CmpInst::ICMP_SGE:
1452                     result = (L >= R);
1453                     break;
1454                 case CmpInst::ICMP_SLT:
1455                     result = (L < R);
1456                     break;
1457                 case CmpInst::ICMP_SLE:
1458                     result = (L <= R);
1459                     break;
1460                 }
1461 
1462                 frame.AssignValue(inst, result, llvm_module);
1463 
1464                 if (log)
1465                 {
1466                     log->Printf("Interpreted an ICmpInst");
1467                     log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
1468                     log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
1469                     log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
1470                 }
1471             }
1472             break;
1473         case Instruction::IntToPtr:
1474             {
1475                 const IntToPtrInst *int_to_ptr_inst = dyn_cast<IntToPtrInst>(inst);
1476 
1477                 if (!int_to_ptr_inst)
1478                 {
1479                     if (log)
1480                         log->Printf("getOpcode() returns IntToPtr, but instruction is not an IntToPtrInst");
1481                     err.SetErrorToGenericError();
1482                     err.SetErrorString(interpreter_internal_error);
1483                     return false;
1484                 }
1485 
1486                 Value *src_operand = int_to_ptr_inst->getOperand(0);
1487 
1488                 lldb_private::Scalar I;
1489 
1490                 if (!frame.EvaluateValue(I, src_operand, llvm_module))
1491                 {
1492                     if (log)
1493                         log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
1494                     err.SetErrorToGenericError();
1495                     err.SetErrorString(bad_value_error);
1496                     return false;
1497                 }
1498 
1499                 frame.AssignValue(inst, I, llvm_module);
1500 
1501                 if (log)
1502                 {
1503                     log->Printf("Interpreted an IntToPtr");
1504                     log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1505                     log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1506                 }
1507             }
1508             break;
1509         case Instruction::Load:
1510             {
1511                 const LoadInst *load_inst = dyn_cast<LoadInst>(inst);
1512 
1513                 if (!load_inst)
1514                 {
1515                     if (log)
1516                         log->Printf("getOpcode() returns Load, but instruction is not a LoadInst");
1517                     err.SetErrorToGenericError();
1518                     err.SetErrorString(interpreter_internal_error);
1519                     return false;
1520                 }
1521 
1522                 // The semantics of Load are:
1523                 //   Create a region D that will contain the loaded data
1524                 //   Resolve the region P containing a pointer
1525                 //   Dereference P to get the region R that the data should be loaded from
1526                 //   Transfer a unit of type type(D) from R to D
1527 
1528                 const Value *pointer_operand = load_inst->getPointerOperand();
1529 
1530                 Type *pointer_ty = pointer_operand->getType();
1531                 PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1532                 if (!pointer_ptr_ty)
1533                 {
1534                     if (log)
1535                         log->Printf("getPointerOperand()->getType() is not a PointerType");
1536                     err.SetErrorToGenericError();
1537                     err.SetErrorString(interpreter_internal_error);
1538                     return false;
1539                 }
1540                 Type *target_ty = pointer_ptr_ty->getElementType();
1541 
1542                 Memory::Region D = frame.ResolveValue(load_inst, llvm_module);
1543                 Memory::Region P = frame.ResolveValue(pointer_operand, llvm_module);
1544 
1545                 if (D.IsInvalid())
1546                 {
1547                     if (log)
1548                         log->Printf("LoadInst's value doesn't resolve to anything");
1549                     err.SetErrorToGenericError();
1550                     err.SetErrorString(bad_value_error);
1551                     return false;
1552                 }
1553 
1554                 if (P.IsInvalid())
1555                 {
1556                     if (log)
1557                         log->Printf("LoadInst's pointer doesn't resolve to anything");
1558                     err.SetErrorToGenericError();
1559                     err.SetErrorString(bad_value_error);
1560                     return false;
1561                 }
1562 
1563                 DataExtractorSP P_extractor(memory.GetExtractor(P));
1564                 DataEncoderSP D_encoder(memory.GetEncoder(D));
1565 
1566                 uint32_t offset = 0;
1567                 lldb::addr_t pointer = P_extractor->GetAddress(&offset);
1568 
1569                 Memory::Region R = memory.Lookup(pointer, target_ty);
1570 
1571                 if (R.IsValid())
1572                 {
1573                     if (!memory.Read(D_encoder->GetDataStart(), R.m_base, target_data.getTypeStoreSize(target_ty)))
1574                     {
1575                         if (log)
1576                             log->Printf("Couldn't read from a region on behalf of a LoadInst");
1577                         err.SetErrorToGenericError();
1578                         err.SetErrorString(memory_read_error);
1579                         return false;
1580                     }
1581                 }
1582                 else
1583                 {
1584                     if (!memory.ReadFromRawPtr(D_encoder->GetDataStart(), pointer, target_data.getTypeStoreSize(target_ty)))
1585                     {
1586                         if (log)
1587                             log->Printf("Couldn't read from a raw pointer on behalf of a LoadInst");
1588                         err.SetErrorToGenericError();
1589                         err.SetErrorString(memory_read_error);
1590                         return false;
1591                     }
1592                 }
1593 
1594                 if (log)
1595                 {
1596                     log->Printf("Interpreted a LoadInst");
1597                     log->Printf("  P : %s", frame.SummarizeValue(pointer_operand).c_str());
1598                     if (R.IsValid())
1599                         log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1600                     else
1601                         log->Printf("  R : raw pointer 0x%llx", (unsigned long long)pointer);
1602                     log->Printf("  D : %s", frame.SummarizeValue(load_inst).c_str());
1603                 }
1604             }
1605             break;
1606         case Instruction::Ret:
1607             {
1608                 if (result_name.IsEmpty())
1609                     return true;
1610 
1611                 GlobalValue *result_value = llvm_module.getNamedValue(result_name.GetCString());
1612 
1613                 if (!frame.ConstructResult(result, result_value, result_name, result_type, llvm_module))
1614                 {
1615                     if (log)
1616                         log->Printf("Couldn't construct the expression's result");
1617                     err.SetErrorToGenericError();
1618                     err.SetErrorString(bad_result_error);
1619                     return false;
1620                 }
1621 
1622                 return true;
1623             }
1624         case Instruction::Store:
1625             {
1626                 const StoreInst *store_inst = dyn_cast<StoreInst>(inst);
1627 
1628                 if (!store_inst)
1629                 {
1630                     if (log)
1631                         log->Printf("getOpcode() returns Store, but instruction is not a StoreInst");
1632                     err.SetErrorToGenericError();
1633                     err.SetErrorString(interpreter_internal_error);
1634                     return false;
1635                 }
1636 
1637                 // The semantics of Store are:
1638                 //   Resolve the region D containing the data to be stored
1639                 //   Resolve the region P containing a pointer
1640                 //   Dereference P to get the region R that the data should be stored in
1641                 //   Transfer a unit of type type(D) from D to R
1642 
1643                 const Value *value_operand = store_inst->getValueOperand();
1644                 const Value *pointer_operand = store_inst->getPointerOperand();
1645 
1646                 Type *pointer_ty = pointer_operand->getType();
1647                 PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1648                 if (!pointer_ptr_ty)
1649                     return false;
1650                 Type *target_ty = pointer_ptr_ty->getElementType();
1651 
1652                 Memory::Region D = frame.ResolveValue(value_operand, llvm_module);
1653                 Memory::Region P = frame.ResolveValue(pointer_operand, llvm_module);
1654 
1655                 if (D.IsInvalid())
1656                 {
1657                     if (log)
1658                         log->Printf("StoreInst's value doesn't resolve to anything");
1659                     err.SetErrorToGenericError();
1660                     err.SetErrorString(bad_value_error);
1661                     return false;
1662                 }
1663 
1664                 if (P.IsInvalid())
1665                 {
1666                     if (log)
1667                         log->Printf("StoreInst's pointer doesn't resolve to anything");
1668                     err.SetErrorToGenericError();
1669                     err.SetErrorString(bad_value_error);
1670                     return false;
1671                 }
1672 
1673                 DataExtractorSP P_extractor(memory.GetExtractor(P));
1674                 DataExtractorSP D_extractor(memory.GetExtractor(D));
1675 
1676                 if (!P_extractor || !D_extractor)
1677                     return false;
1678 
1679                 uint32_t offset = 0;
1680                 lldb::addr_t pointer = P_extractor->GetAddress(&offset);
1681 
1682                 Memory::Region R = memory.Lookup(pointer, target_ty);
1683 
1684                 if (R.IsValid())
1685                 {
1686                     if (!memory.Write(R.m_base, D_extractor->GetDataStart(), target_data.getTypeStoreSize(target_ty)))
1687                     {
1688                         if (log)
1689                             log->Printf("Couldn't write to a region on behalf of a LoadInst");
1690                         err.SetErrorToGenericError();
1691                         err.SetErrorString(memory_write_error);
1692                         return false;
1693                     }
1694                 }
1695                 else
1696                 {
1697                     if (!memory.WriteToRawPtr(pointer, D_extractor->GetDataStart(), target_data.getTypeStoreSize(target_ty)))
1698                     {
1699                         if (log)
1700                             log->Printf("Couldn't write to a raw pointer on behalf of a LoadInst");
1701                         err.SetErrorToGenericError();
1702                         err.SetErrorString(memory_write_error);
1703                         return false;
1704                     }
1705                 }
1706 
1707 
1708                 if (log)
1709                 {
1710                     log->Printf("Interpreted a StoreInst");
1711                     log->Printf("  D : %s", frame.SummarizeValue(value_operand).c_str());
1712                     log->Printf("  P : %s", frame.SummarizeValue(pointer_operand).c_str());
1713                     log->Printf("  R : %s", memory.SummarizeRegion(R).c_str());
1714                 }
1715             }
1716             break;
1717         }
1718 
1719         ++frame.m_ii;
1720     }
1721 
1722     if (num_insts >= 4096)
1723     {
1724         err.SetErrorToGenericError();
1725         err.SetErrorString(infinite_loop_error);
1726         return false;
1727     }
1728 
1729     return false;
1730 }
1731