1 //===-- IRMemoryMap.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/DataBufferHeap.h"
11 #include "lldb/Core/DataExtractor.h"
12 #include "lldb/Core/Error.h"
13 #include "lldb/Core/Log.h"
14 #include "lldb/Core/Scalar.h"
15 #include "lldb/Expression/IRMemoryMap.h"
16 #include "lldb/Target/Process.h"
17 #include "lldb/Target/Target.h"
18 
19 using namespace lldb_private;
20 
21 IRMemoryMap::IRMemoryMap (lldb::TargetSP target_sp) :
22     m_target_wp(target_sp)
23 {
24     if (target_sp)
25         m_process_wp = target_sp->GetProcessSP();
26 }
27 
28 IRMemoryMap::~IRMemoryMap ()
29 {
30     lldb::ProcessSP process_sp = m_process_wp.lock();
31 
32     if (process_sp)
33     {
34         AllocationMap::iterator iter;
35 
36         Error err;
37 
38         while ((iter = m_allocations.begin()) != m_allocations.end())
39         {
40             err.Clear();
41             if (iter->second.m_leak)
42                 m_allocations.erase(iter);
43             else
44                 Free(iter->first, err);
45         }
46     }
47 }
48 
49 lldb::addr_t
50 IRMemoryMap::FindSpace (size_t size)
51 {
52     lldb::TargetSP target_sp = m_target_wp.lock();
53     lldb::ProcessSP process_sp = m_process_wp.lock();
54 
55     lldb::addr_t ret = LLDB_INVALID_ADDRESS;
56     if (size == 0)
57         return ret;
58 
59     if (process_sp && process_sp->CanJIT() && process_sp->IsAlive())
60     {
61         Error alloc_error;
62 
63         ret = process_sp->AllocateMemory(size, lldb::ePermissionsReadable | lldb::ePermissionsWritable, alloc_error);
64 
65         if (!alloc_error.Success())
66             return LLDB_INVALID_ADDRESS;
67         else
68             return ret;
69     }
70 
71     ret = 0;
72     if (!m_allocations.empty())
73     {
74         auto back = m_allocations.rbegin();
75         lldb::addr_t addr = back->first;
76         size_t alloc_size = back->second.m_size;
77         ret = llvm::RoundUpToAlignment(addr+alloc_size, 4096);
78     }
79 
80     return ret;
81 }
82 
83 IRMemoryMap::AllocationMap::iterator
84 IRMemoryMap::FindAllocation (lldb::addr_t addr, size_t size)
85 {
86     if (addr == LLDB_INVALID_ADDRESS)
87         return m_allocations.end();
88 
89     AllocationMap::iterator iter = m_allocations.lower_bound (addr);
90 
91     if (iter == m_allocations.end() ||
92         iter->first > addr)
93     {
94         if (iter == m_allocations.begin())
95             return m_allocations.end();
96         iter--;
97     }
98 
99     if (iter->first <= addr && iter->first + iter->second.m_size >= addr + size)
100         return iter;
101 
102     return m_allocations.end();
103 }
104 
105 bool
106 IRMemoryMap::IntersectsAllocation (lldb::addr_t addr, size_t size) const
107 {
108     if (addr == LLDB_INVALID_ADDRESS)
109         return false;
110 
111     AllocationMap::const_iterator iter = m_allocations.lower_bound (addr);
112 
113     // Since we only know that the returned interval begins at a location greater than or
114     // equal to where the given interval begins, it's possible that the given interval
115     // intersects either the returned interval or the previous interval.  Thus, we need to
116     // check both. Note that we only need to check these two intervals.  Since all intervals
117     // are disjoint it is not possible that an adjacent interval does not intersect, but a
118     // non-adjacent interval does intersect.
119     if (iter != m_allocations.end()) {
120         if (AllocationsIntersect(addr, size, iter->second.m_process_start, iter->second.m_size))
121             return true;
122     }
123 
124     if (iter != m_allocations.begin()) {
125         --iter;
126         if (AllocationsIntersect(addr, size, iter->second.m_process_start, iter->second.m_size))
127             return true;
128     }
129 
130     return false;
131 }
132 
133 bool
134 IRMemoryMap::AllocationsIntersect(lldb::addr_t addr1, size_t size1, lldb::addr_t addr2, size_t size2) {
135   // Given two half open intervals [A, B) and [X, Y), the only 6 permutations that satisfy
136   // A<B and X<Y are the following:
137   // A B X Y
138   // A X B Y  (intersects)
139   // A X Y B  (intersects)
140   // X A B Y  (intersects)
141   // X A Y B  (intersects)
142   // X Y A B
143   // The first is B <= X, and the last is Y <= A.
144   // So the condition is !(B <= X || Y <= A)), or (X < B && A < Y)
145   return (addr2 < (addr1 + size1)) && (addr1 < (addr2 + size2));
146 }
147 
148 lldb::ByteOrder
149 IRMemoryMap::GetByteOrder()
150 {
151     lldb::ProcessSP process_sp = m_process_wp.lock();
152 
153     if (process_sp)
154         return process_sp->GetByteOrder();
155 
156     lldb::TargetSP target_sp = m_target_wp.lock();
157 
158     if (target_sp)
159         return target_sp->GetArchitecture().GetByteOrder();
160 
161     return lldb::eByteOrderInvalid;
162 }
163 
164 uint32_t
165 IRMemoryMap::GetAddressByteSize()
166 {
167     lldb::ProcessSP process_sp = m_process_wp.lock();
168 
169     if (process_sp)
170         return process_sp->GetAddressByteSize();
171 
172     lldb::TargetSP target_sp = m_target_wp.lock();
173 
174     if (target_sp)
175         return target_sp->GetArchitecture().GetAddressByteSize();
176 
177     return UINT32_MAX;
178 }
179 
180 ExecutionContextScope *
181 IRMemoryMap::GetBestExecutionContextScope() const
182 {
183     lldb::ProcessSP process_sp = m_process_wp.lock();
184 
185     if (process_sp)
186         return process_sp.get();
187 
188     lldb::TargetSP target_sp = m_target_wp.lock();
189 
190     if (target_sp)
191         return target_sp.get();
192 
193     return NULL;
194 }
195 
196 IRMemoryMap::Allocation::Allocation (lldb::addr_t process_alloc,
197                                      lldb::addr_t process_start,
198                                      size_t size,
199                                      uint32_t permissions,
200                                      uint8_t alignment,
201                                      AllocationPolicy policy) :
202     m_process_alloc (process_alloc),
203     m_process_start (process_start),
204     m_size (size),
205     m_permissions (permissions),
206     m_alignment (alignment),
207     m_policy (policy),
208     m_leak (false)
209 {
210     switch (policy)
211     {
212         default:
213             assert (0 && "We cannot reach this!");
214         case eAllocationPolicyHostOnly:
215             m_data.SetByteSize(size);
216             memset(m_data.GetBytes(), 0, size);
217             break;
218         case eAllocationPolicyProcessOnly:
219             break;
220         case eAllocationPolicyMirror:
221             m_data.SetByteSize(size);
222             memset(m_data.GetBytes(), 0, size);
223             break;
224     }
225 }
226 
227 lldb::addr_t
228 IRMemoryMap::Malloc (size_t size, uint8_t alignment, uint32_t permissions, AllocationPolicy policy, Error &error)
229 {
230     lldb_private::Log *log (lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
231     error.Clear();
232 
233     lldb::ProcessSP process_sp;
234     lldb::addr_t    allocation_address  = LLDB_INVALID_ADDRESS;
235     lldb::addr_t    aligned_address     = LLDB_INVALID_ADDRESS;
236 
237     size_t          alignment_mask = alignment - 1;
238     size_t          allocation_size;
239 
240     if (size == 0)
241         allocation_size = alignment;
242     else
243         allocation_size = (size & alignment_mask) ? ((size + alignment) & (~alignment_mask)) : size;
244 
245     switch (policy)
246     {
247     default:
248         error.SetErrorToGenericError();
249         error.SetErrorString("Couldn't malloc: invalid allocation policy");
250         return LLDB_INVALID_ADDRESS;
251     case eAllocationPolicyHostOnly:
252         allocation_address = FindSpace(allocation_size);
253         if (allocation_address == LLDB_INVALID_ADDRESS)
254         {
255             error.SetErrorToGenericError();
256             error.SetErrorString("Couldn't malloc: address space is full");
257             return LLDB_INVALID_ADDRESS;
258         }
259         break;
260     case eAllocationPolicyMirror:
261         process_sp = m_process_wp.lock();
262         if (log)
263             log->Printf ("IRMemoryMap::%s process_sp=0x%" PRIx64 ", process_sp->CanJIT()=%s, process_sp->IsAlive()=%s", __FUNCTION__, (lldb::addr_t) process_sp.get (), process_sp && process_sp->CanJIT () ? "true" : "false", process_sp && process_sp->IsAlive () ? "true" : "false");
264         if (process_sp && process_sp->CanJIT() && process_sp->IsAlive())
265         {
266             allocation_address = process_sp->AllocateMemory(allocation_size, permissions, error);
267             if (!error.Success())
268                 return LLDB_INVALID_ADDRESS;
269         }
270         else
271         {
272             if (log)
273                 log->Printf ("IRMemoryMap::%s switching to eAllocationPolicyHostOnly due to failed condition (see previous expr log message)", __FUNCTION__);
274             policy = eAllocationPolicyHostOnly;
275             allocation_address = FindSpace(allocation_size);
276             if (allocation_address == LLDB_INVALID_ADDRESS)
277             {
278                 error.SetErrorToGenericError();
279                 error.SetErrorString("Couldn't malloc: address space is full");
280                 return LLDB_INVALID_ADDRESS;
281             }
282         }
283         break;
284     case eAllocationPolicyProcessOnly:
285         process_sp = m_process_wp.lock();
286         if (process_sp)
287         {
288             if (process_sp->CanJIT() && process_sp->IsAlive())
289             {
290                 allocation_address = process_sp->AllocateMemory(allocation_size, permissions, error);
291                 if (!error.Success())
292                     return LLDB_INVALID_ADDRESS;
293             }
294             else
295             {
296                 error.SetErrorToGenericError();
297                 error.SetErrorString("Couldn't malloc: process doesn't support allocating memory");
298                 return LLDB_INVALID_ADDRESS;
299             }
300         }
301         else
302         {
303             error.SetErrorToGenericError();
304             error.SetErrorString("Couldn't malloc: process doesn't exist, and this memory must be in the process");
305             return LLDB_INVALID_ADDRESS;
306         }
307         break;
308     }
309 
310 
311     lldb::addr_t mask = alignment - 1;
312     aligned_address = (allocation_address + mask) & (~mask);
313 
314     m_allocations[aligned_address] = Allocation(allocation_address,
315                                                 aligned_address,
316                                                 allocation_size,
317                                                 permissions,
318                                                 alignment,
319                                                 policy);
320 
321     if (log)
322     {
323         const char * policy_string;
324 
325         switch (policy)
326         {
327         default:
328             policy_string = "<invalid policy>";
329             break;
330         case eAllocationPolicyHostOnly:
331             policy_string = "eAllocationPolicyHostOnly";
332             break;
333         case eAllocationPolicyProcessOnly:
334             policy_string = "eAllocationPolicyProcessOnly";
335             break;
336         case eAllocationPolicyMirror:
337             policy_string = "eAllocationPolicyMirror";
338             break;
339         }
340 
341         log->Printf("IRMemoryMap::Malloc (%" PRIu64 ", 0x%" PRIx64 ", 0x%" PRIx64 ", %s) -> 0x%" PRIx64,
342                     (uint64_t)allocation_size,
343                     (uint64_t)alignment,
344                     (uint64_t)permissions,
345                     policy_string,
346                     aligned_address);
347     }
348 
349     return aligned_address;
350 }
351 
352 void
353 IRMemoryMap::Leak (lldb::addr_t process_address, Error &error)
354 {
355     error.Clear();
356 
357     AllocationMap::iterator iter = m_allocations.find(process_address);
358 
359     if (iter == m_allocations.end())
360     {
361         error.SetErrorToGenericError();
362         error.SetErrorString("Couldn't leak: allocation doesn't exist");
363         return;
364     }
365 
366     Allocation &allocation = iter->second;
367 
368     allocation.m_leak = true;
369 }
370 
371 void
372 IRMemoryMap::Free (lldb::addr_t process_address, Error &error)
373 {
374     error.Clear();
375 
376     AllocationMap::iterator iter = m_allocations.find(process_address);
377 
378     if (iter == m_allocations.end())
379     {
380         error.SetErrorToGenericError();
381         error.SetErrorString("Couldn't free: allocation doesn't exist");
382         return;
383     }
384 
385     Allocation &allocation = iter->second;
386 
387     switch (allocation.m_policy)
388     {
389     default:
390     case eAllocationPolicyHostOnly:
391         {
392             lldb::ProcessSP process_sp = m_process_wp.lock();
393             if (process_sp)
394             {
395                 if (process_sp->CanJIT() && process_sp->IsAlive())
396                     process_sp->DeallocateMemory(allocation.m_process_alloc); // FindSpace allocated this for real
397             }
398 
399             break;
400         }
401     case eAllocationPolicyMirror:
402     case eAllocationPolicyProcessOnly:
403         {
404             lldb::ProcessSP process_sp = m_process_wp.lock();
405             if (process_sp)
406                 process_sp->DeallocateMemory(allocation.m_process_alloc);
407         }
408     }
409 
410     if (lldb_private::Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS))
411     {
412         log->Printf("IRMemoryMap::Free (0x%" PRIx64 ") freed [0x%" PRIx64 "..0x%" PRIx64 ")",
413                     (uint64_t)process_address,
414                     iter->second.m_process_start,
415                     iter->second.m_process_start + iter->second.m_size);
416     }
417 
418     m_allocations.erase(iter);
419 }
420 
421 bool
422 IRMemoryMap::GetAllocSize(lldb::addr_t address, size_t &size)
423 {
424     AllocationMap::iterator iter = FindAllocation(address, size);
425     if (iter == m_allocations.end())
426         return false;
427 
428     Allocation &al = iter->second;
429 
430     if (address > (al.m_process_start + al.m_size))
431     {
432         size = 0;
433         return false;
434     }
435 
436     if (address > al.m_process_start)
437     {
438         int dif = address - al.m_process_start;
439         size = al.m_size - dif;
440         return true;
441     }
442 
443     size = al.m_size;
444     return true;
445 }
446 
447 void
448 IRMemoryMap::WriteMemory (lldb::addr_t process_address, const uint8_t *bytes, size_t size, Error &error)
449 {
450     error.Clear();
451 
452     AllocationMap::iterator iter = FindAllocation(process_address, size);
453 
454     if (iter == m_allocations.end())
455     {
456         lldb::ProcessSP process_sp = m_process_wp.lock();
457 
458         if (process_sp)
459         {
460             process_sp->WriteMemory(process_address, bytes, size, error);
461             return;
462         }
463 
464         error.SetErrorToGenericError();
465         error.SetErrorString("Couldn't write: no allocation contains the target range and the process doesn't exist");
466         return;
467     }
468 
469     Allocation &allocation = iter->second;
470 
471     uint64_t offset = process_address - allocation.m_process_start;
472 
473     lldb::ProcessSP process_sp;
474 
475     switch (allocation.m_policy)
476     {
477     default:
478         error.SetErrorToGenericError();
479         error.SetErrorString("Couldn't write: invalid allocation policy");
480         return;
481     case eAllocationPolicyHostOnly:
482         if (!allocation.m_data.GetByteSize())
483         {
484             error.SetErrorToGenericError();
485             error.SetErrorString("Couldn't write: data buffer is empty");
486             return;
487         }
488         ::memcpy (allocation.m_data.GetBytes() + offset, bytes, size);
489         break;
490     case eAllocationPolicyMirror:
491         if (!allocation.m_data.GetByteSize())
492         {
493             error.SetErrorToGenericError();
494             error.SetErrorString("Couldn't write: data buffer is empty");
495             return;
496         }
497         ::memcpy (allocation.m_data.GetBytes() + offset, bytes, size);
498         process_sp = m_process_wp.lock();
499         if (process_sp)
500         {
501             process_sp->WriteMemory(process_address, bytes, size, error);
502             if (!error.Success())
503                 return;
504         }
505         break;
506     case eAllocationPolicyProcessOnly:
507         process_sp = m_process_wp.lock();
508         if (process_sp)
509         {
510             process_sp->WriteMemory(process_address, bytes, size, error);
511             if (!error.Success())
512                 return;
513         }
514         break;
515     }
516 
517     if (lldb_private::Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS))
518     {
519         log->Printf("IRMemoryMap::WriteMemory (0x%" PRIx64 ", 0x%" PRIx64 ", 0x%" PRId64 ") went to [0x%" PRIx64 "..0x%" PRIx64 ")",
520                     (uint64_t)process_address,
521                     (uint64_t)bytes,
522                     (uint64_t)size,
523                     (uint64_t)allocation.m_process_start,
524                     (uint64_t)allocation.m_process_start + (uint64_t)allocation.m_size);
525     }
526 }
527 
528 void
529 IRMemoryMap::WriteScalarToMemory (lldb::addr_t process_address, Scalar &scalar, size_t size, Error &error)
530 {
531     error.Clear();
532 
533     if (size == UINT32_MAX)
534         size = scalar.GetByteSize();
535 
536     if (size > 0)
537     {
538         uint8_t buf[32];
539         const size_t mem_size = scalar.GetAsMemoryData (buf, size, GetByteOrder(), error);
540         if (mem_size > 0)
541         {
542             return WriteMemory(process_address, buf, mem_size, error);
543         }
544         else
545         {
546             error.SetErrorToGenericError();
547             error.SetErrorString ("Couldn't write scalar: failed to get scalar as memory data");
548         }
549     }
550     else
551     {
552         error.SetErrorToGenericError();
553         error.SetErrorString ("Couldn't write scalar: its size was zero");
554     }
555     return;
556 }
557 
558 void
559 IRMemoryMap::WritePointerToMemory (lldb::addr_t process_address, lldb::addr_t address, Error &error)
560 {
561     error.Clear();
562 
563     Scalar scalar(address);
564 
565     WriteScalarToMemory(process_address, scalar, GetAddressByteSize(), error);
566 }
567 
568 void
569 IRMemoryMap::ReadMemory (uint8_t *bytes, lldb::addr_t process_address, size_t size, Error &error)
570 {
571     error.Clear();
572 
573     AllocationMap::iterator iter = FindAllocation(process_address, size);
574 
575     if (iter == m_allocations.end())
576     {
577         lldb::ProcessSP process_sp = m_process_wp.lock();
578 
579         if (process_sp)
580         {
581             process_sp->ReadMemory(process_address, bytes, size, error);
582             return;
583         }
584 
585         lldb::TargetSP target_sp = m_target_wp.lock();
586 
587         if (target_sp)
588         {
589             Address absolute_address(process_address);
590             target_sp->ReadMemory(absolute_address, false, bytes, size, error);
591             return;
592         }
593 
594         error.SetErrorToGenericError();
595         error.SetErrorString("Couldn't read: no allocation contains the target range, and neither the process nor the target exist");
596         return;
597     }
598 
599     Allocation &allocation = iter->second;
600 
601     uint64_t offset = process_address - allocation.m_process_start;
602 
603     if (offset > allocation.m_size)
604     {
605         error.SetErrorToGenericError();
606         error.SetErrorString("Couldn't read: data is not in the allocation");
607         return;
608     }
609 
610     lldb::ProcessSP process_sp;
611 
612     switch (allocation.m_policy)
613     {
614     default:
615         error.SetErrorToGenericError();
616         error.SetErrorString("Couldn't read: invalid allocation policy");
617         return;
618     case eAllocationPolicyHostOnly:
619         if (!allocation.m_data.GetByteSize())
620         {
621             error.SetErrorToGenericError();
622             error.SetErrorString("Couldn't read: data buffer is empty");
623             return;
624         }
625         if (allocation.m_data.GetByteSize() < offset + size)
626         {
627             error.SetErrorToGenericError();
628             error.SetErrorString("Couldn't read: not enough underlying data");
629             return;
630         }
631 
632         ::memcpy (bytes, allocation.m_data.GetBytes() + offset, size);
633         break;
634     case eAllocationPolicyMirror:
635         process_sp = m_process_wp.lock();
636         if (process_sp)
637         {
638             process_sp->ReadMemory(process_address, bytes, size, error);
639             if (!error.Success())
640                 return;
641         }
642         else
643         {
644             if (!allocation.m_data.GetByteSize())
645             {
646                 error.SetErrorToGenericError();
647                 error.SetErrorString("Couldn't read: data buffer is empty");
648                 return;
649             }
650             ::memcpy (bytes, allocation.m_data.GetBytes() + offset, size);
651         }
652         break;
653     case eAllocationPolicyProcessOnly:
654         process_sp = m_process_wp.lock();
655         if (process_sp)
656         {
657             process_sp->ReadMemory(process_address, bytes, size, error);
658             if (!error.Success())
659                 return;
660         }
661         break;
662     }
663 
664     if (lldb_private::Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS))
665     {
666         log->Printf("IRMemoryMap::ReadMemory (0x%" PRIx64 ", 0x%" PRIx64 ", 0x%" PRId64 ") came from [0x%" PRIx64 "..0x%" PRIx64 ")",
667                     (uint64_t)process_address,
668                     (uint64_t)bytes,
669                     (uint64_t)size,
670                     (uint64_t)allocation.m_process_start,
671                     (uint64_t)allocation.m_process_start + (uint64_t)allocation.m_size);
672     }
673 }
674 
675 void
676 IRMemoryMap::ReadScalarFromMemory (Scalar &scalar, lldb::addr_t process_address, size_t size, Error &error)
677 {
678     error.Clear();
679 
680     if (size > 0)
681     {
682         DataBufferHeap buf(size, 0);
683         ReadMemory(buf.GetBytes(), process_address, size, error);
684 
685         if (!error.Success())
686             return;
687 
688         DataExtractor extractor(buf.GetBytes(), buf.GetByteSize(), GetByteOrder(), GetAddressByteSize());
689 
690         lldb::offset_t offset = 0;
691 
692         switch (size)
693         {
694         default:
695             error.SetErrorToGenericError();
696             error.SetErrorStringWithFormat("Couldn't read scalar: unsupported size %" PRIu64, (uint64_t)size);
697             return;
698         case 1: scalar = extractor.GetU8(&offset);  break;
699         case 2: scalar = extractor.GetU16(&offset); break;
700         case 4: scalar = extractor.GetU32(&offset); break;
701         case 8: scalar = extractor.GetU64(&offset); break;
702         }
703     }
704     else
705     {
706         error.SetErrorToGenericError();
707         error.SetErrorString ("Couldn't read scalar: its size was zero");
708     }
709     return;
710 }
711 
712 void
713 IRMemoryMap::ReadPointerFromMemory (lldb::addr_t *address, lldb::addr_t process_address, Error &error)
714 {
715     error.Clear();
716 
717     Scalar pointer_scalar;
718     ReadScalarFromMemory(pointer_scalar, process_address, GetAddressByteSize(), error);
719 
720     if (!error.Success())
721         return;
722 
723     *address = pointer_scalar.ULongLong();
724 
725     return;
726 }
727 
728 void
729 IRMemoryMap::GetMemoryData (DataExtractor &extractor, lldb::addr_t process_address, size_t size, Error &error)
730 {
731     error.Clear();
732 
733     if (size > 0)
734     {
735         AllocationMap::iterator iter = FindAllocation(process_address, size);
736 
737         if (iter == m_allocations.end())
738         {
739             error.SetErrorToGenericError();
740             error.SetErrorStringWithFormat("Couldn't find an allocation containing [0x%" PRIx64 "..0x%" PRIx64 ")", process_address, process_address + size);
741             return;
742         }
743 
744         Allocation &allocation = iter->second;
745 
746         switch (allocation.m_policy)
747         {
748         default:
749             error.SetErrorToGenericError();
750             error.SetErrorString("Couldn't get memory data: invalid allocation policy");
751             return;
752         case eAllocationPolicyProcessOnly:
753             error.SetErrorToGenericError();
754             error.SetErrorString("Couldn't get memory data: memory is only in the target");
755             return;
756         case eAllocationPolicyMirror:
757             {
758                 lldb::ProcessSP process_sp = m_process_wp.lock();
759 
760                 if (!allocation.m_data.GetByteSize())
761                 {
762                     error.SetErrorToGenericError();
763                     error.SetErrorString("Couldn't get memory data: data buffer is empty");
764                     return;
765                 }
766                 if (process_sp)
767                 {
768                     process_sp->ReadMemory(allocation.m_process_start, allocation.m_data.GetBytes(), allocation.m_data.GetByteSize(), error);
769                     if (!error.Success())
770                         return;
771                     uint64_t offset = process_address - allocation.m_process_start;
772                     extractor = DataExtractor(allocation.m_data.GetBytes() + offset, size, GetByteOrder(), GetAddressByteSize());
773                     return;
774                 }
775             }
776         case eAllocationPolicyHostOnly:
777             if (!allocation.m_data.GetByteSize())
778             {
779                 error.SetErrorToGenericError();
780                 error.SetErrorString("Couldn't get memory data: data buffer is empty");
781                 return;
782             }
783             uint64_t offset = process_address - allocation.m_process_start;
784             extractor = DataExtractor(allocation.m_data.GetBytes() + offset, size, GetByteOrder(), GetAddressByteSize());
785             return;
786         }
787     }
788     else
789     {
790         error.SetErrorToGenericError();
791         error.SetErrorString ("Couldn't get memory data: its size was zero");
792         return;
793     }
794 }
795