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