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