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/Expression/IRInterpreter.h"
11 #include "lldb/Core/ConstString.h"
12 #include "lldb/Core/DataExtractor.h"
13 #include "lldb/Core/Error.h"
14 #include "lldb/Core/Log.h"
15 #include "lldb/Core/Module.h"
16 #include "lldb/Core/ModuleSpec.h"
17 #include "lldb/Core/Scalar.h"
18 #include "lldb/Core/StreamString.h"
19 #include "lldb/Core/ValueObject.h"
20 #include "lldb/Expression/DiagnosticManager.h"
21 #include "lldb/Expression/IRExecutionUnit.h"
22 #include "lldb/Expression/IRMemoryMap.h"
23 #include "lldb/Host/Endian.h"
24 
25 #include "lldb/Target/ABI.h"
26 #include "lldb/Target/ExecutionContext.h"
27 #include "lldb/Target/Target.h"
28 #include "lldb/Target/Thread.h"
29 #include "lldb/Target/ThreadPlan.h"
30 #include "lldb/Target/ThreadPlanCallFunctionUsingABI.h"
31 
32 #include "llvm/IR/Constants.h"
33 #include "llvm/IR/DataLayout.h"
34 #include "llvm/IR/Function.h"
35 #include "llvm/IR/Instructions.h"
36 #include "llvm/IR/Intrinsics.h"
37 #include "llvm/IR/LLVMContext.h"
38 #include "llvm/IR/Module.h"
39 #include "llvm/IR/Operator.h"
40 #include "llvm/Support/raw_ostream.h"
41 
42 #include <map>
43 
44 using namespace llvm;
45 
46 static std::string
47 PrintValue(const Value *value, bool truncate = false)
48 {
49     std::string s;
50     raw_string_ostream rso(s);
51     value->print(rso);
52     rso.flush();
53     if (truncate)
54         s.resize(s.length() - 1);
55 
56     size_t offset;
57     while ((offset = s.find('\n')) != s.npos)
58         s.erase(offset, 1);
59     while (s[0] == ' ' || s[0] == '\t')
60         s.erase(0, 1);
61 
62     return s;
63 }
64 
65 static std::string
66 PrintType(const Type *type, bool truncate = false)
67 {
68     std::string s;
69     raw_string_ostream rso(s);
70     type->print(rso);
71     rso.flush();
72     if (truncate)
73         s.resize(s.length() - 1);
74     return s;
75 }
76 
77 static bool
78 CanIgnoreCall (const CallInst *call)
79 {
80     const llvm::Function *called_function = call->getCalledFunction();
81 
82     if (!called_function)
83         return false;
84 
85     if (called_function->isIntrinsic())
86     {
87         switch (called_function->getIntrinsicID())
88         {
89         default:
90             break;
91         case llvm::Intrinsic::dbg_declare:
92         case llvm::Intrinsic::dbg_value:
93             return true;
94         }
95     }
96 
97     return false;
98 }
99 
100 class InterpreterStackFrame
101 {
102 public:
103     typedef std::map <const Value*, lldb::addr_t> ValueMap;
104 
105     ValueMap                                m_values;
106     DataLayout                             &m_target_data;
107     lldb_private::IRExecutionUnit          &m_execution_unit;
108     const BasicBlock                       *m_bb;
109     BasicBlock::const_iterator              m_ii;
110     BasicBlock::const_iterator              m_ie;
111 
112     lldb::addr_t                            m_frame_process_address;
113     size_t                                  m_frame_size;
114     lldb::addr_t                            m_stack_pointer;
115 
116     lldb::ByteOrder                         m_byte_order;
117     size_t                                  m_addr_byte_size;
118 
119     InterpreterStackFrame (DataLayout &target_data,
120                            lldb_private::IRExecutionUnit &execution_unit,
121                            lldb::addr_t stack_frame_bottom,
122                            lldb::addr_t stack_frame_top) :
123         m_target_data (target_data),
124         m_execution_unit (execution_unit)
125     {
126         m_byte_order = (target_data.isLittleEndian() ? lldb::eByteOrderLittle : lldb::eByteOrderBig);
127         m_addr_byte_size = (target_data.getPointerSize(0));
128 
129         m_frame_process_address = stack_frame_bottom;
130         m_frame_size = stack_frame_top - stack_frame_bottom;
131         m_stack_pointer = stack_frame_top;
132     }
133 
134     ~InterpreterStackFrame ()
135     {
136     }
137 
138     void Jump (const BasicBlock *bb)
139     {
140         m_bb = bb;
141         m_ii = m_bb->begin();
142         m_ie = m_bb->end();
143     }
144 
145     std::string SummarizeValue (const Value *value)
146     {
147         lldb_private::StreamString ss;
148 
149         ss.Printf("%s", PrintValue(value).c_str());
150 
151         ValueMap::iterator i = m_values.find(value);
152 
153         if (i != m_values.end())
154         {
155             lldb::addr_t addr = i->second;
156 
157             ss.Printf(" 0x%llx", (unsigned long long)addr);
158         }
159 
160         return ss.GetString();
161     }
162 
163     bool AssignToMatchType (lldb_private::Scalar &scalar, uint64_t u64value, Type *type)
164     {
165         size_t type_size = m_target_data.getTypeStoreSize(type);
166 
167         switch (type_size)
168         {
169         case 1:
170             scalar = (uint8_t)u64value;
171             break;
172         case 2:
173             scalar = (uint16_t)u64value;
174             break;
175         case 4:
176             scalar = (uint32_t)u64value;
177             break;
178         case 8:
179             scalar = (uint64_t)u64value;
180             break;
181         default:
182             return false;
183         }
184 
185         return true;
186     }
187 
188     bool EvaluateValue (lldb_private::Scalar &scalar, const Value *value, Module &module)
189     {
190         const Constant *constant = dyn_cast<Constant>(value);
191 
192         if (constant)
193         {
194             APInt value_apint;
195 
196             if (!ResolveConstantValue(value_apint, constant))
197                 return false;
198 
199             return AssignToMatchType(scalar, value_apint.getLimitedValue(), value->getType());
200         }
201         else
202         {
203             lldb::addr_t process_address = ResolveValue(value, module);
204             size_t value_size = m_target_data.getTypeStoreSize(value->getType());
205 
206             lldb_private::DataExtractor value_extractor;
207             lldb_private::Error extract_error;
208 
209             m_execution_unit.GetMemoryData(value_extractor, process_address, value_size, extract_error);
210 
211             if (!extract_error.Success())
212                 return false;
213 
214             lldb::offset_t offset = 0;
215             if (value_size == 1 || value_size == 2 || value_size == 4 || value_size == 8)
216             {
217                 uint64_t u64value = value_extractor.GetMaxU64(&offset, value_size);
218                 return AssignToMatchType(scalar, u64value, value->getType());
219             }
220         }
221 
222         return false;
223     }
224 
225     bool AssignValue (const Value *value, lldb_private::Scalar &scalar, Module &module)
226     {
227         lldb::addr_t process_address = ResolveValue (value, module);
228 
229         if (process_address == LLDB_INVALID_ADDRESS)
230             return false;
231 
232         lldb_private::Scalar cast_scalar;
233 
234         if (!AssignToMatchType(cast_scalar, scalar.ULongLong(), value->getType()))
235             return false;
236 
237         size_t value_byte_size = m_target_data.getTypeStoreSize(value->getType());
238 
239         lldb_private::DataBufferHeap buf(value_byte_size, 0);
240 
241         lldb_private::Error get_data_error;
242 
243         if (!cast_scalar.GetAsMemoryData(buf.GetBytes(), buf.GetByteSize(), m_byte_order, get_data_error))
244             return false;
245 
246         lldb_private::Error write_error;
247 
248         m_execution_unit.WriteMemory(process_address, buf.GetBytes(), buf.GetByteSize(), write_error);
249 
250         return write_error.Success();
251     }
252 
253     bool ResolveConstantValue (APInt &value, const Constant *constant)
254     {
255         switch (constant->getValueID())
256         {
257         default:
258             break;
259         case Value::FunctionVal:
260             if (const Function *constant_func = dyn_cast<Function>(constant))
261             {
262                 lldb_private::ConstString name(constant_func->getName());
263                 lldb::addr_t addr = m_execution_unit.FindSymbol(name);
264                 if (addr == LLDB_INVALID_ADDRESS)
265                     return false;
266                 value = APInt(m_target_data.getPointerSizeInBits(), addr);
267                 return true;
268             }
269             break;
270         case Value::ConstantIntVal:
271             if (const ConstantInt *constant_int = dyn_cast<ConstantInt>(constant))
272             {
273                 value = constant_int->getValue();
274                 return true;
275             }
276             break;
277         case Value::ConstantFPVal:
278             if (const ConstantFP *constant_fp = dyn_cast<ConstantFP>(constant))
279             {
280                 value = constant_fp->getValueAPF().bitcastToAPInt();
281                 return true;
282             }
283             break;
284         case Value::ConstantExprVal:
285             if (const ConstantExpr *constant_expr = dyn_cast<ConstantExpr>(constant))
286             {
287                 switch (constant_expr->getOpcode())
288                 {
289                     default:
290                         return false;
291                     case Instruction::IntToPtr:
292                     case Instruction::PtrToInt:
293                     case Instruction::BitCast:
294                         return ResolveConstantValue(value, constant_expr->getOperand(0));
295                     case Instruction::GetElementPtr:
296                     {
297                         ConstantExpr::const_op_iterator op_cursor = constant_expr->op_begin();
298                         ConstantExpr::const_op_iterator op_end = constant_expr->op_end();
299 
300                         Constant *base = dyn_cast<Constant>(*op_cursor);
301 
302                         if (!base)
303                             return false;
304 
305                         if (!ResolveConstantValue(value, base))
306                             return false;
307 
308                         op_cursor++;
309 
310                         if (op_cursor == op_end)
311                             return true; // no offset to apply!
312 
313                         SmallVector <Value *, 8> indices (op_cursor, op_end);
314 
315                         Type *src_elem_ty = cast<GEPOperator>(constant_expr)->getSourceElementType();
316                         uint64_t offset = m_target_data.getIndexedOffsetInType(src_elem_ty, indices);
317 
318                         const bool is_signed = true;
319                         value += APInt(value.getBitWidth(), offset, is_signed);
320 
321                         return true;
322                     }
323                 }
324             }
325             break;
326         case Value::ConstantPointerNullVal:
327             if (isa<ConstantPointerNull>(constant))
328             {
329                 value = APInt(m_target_data.getPointerSizeInBits(), 0);
330                 return true;
331             }
332             break;
333         }
334         return false;
335     }
336 
337     bool MakeArgument(const Argument *value, uint64_t address)
338     {
339         lldb::addr_t data_address = Malloc(value->getType());
340 
341         if (data_address == LLDB_INVALID_ADDRESS)
342             return false;
343 
344         lldb_private::Error write_error;
345 
346         m_execution_unit.WritePointerToMemory(data_address, address, write_error);
347 
348         if (!write_error.Success())
349         {
350             lldb_private::Error free_error;
351             m_execution_unit.Free(data_address, free_error);
352             return false;
353         }
354 
355         m_values[value] = data_address;
356 
357         lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
358 
359         if (log)
360         {
361             log->Printf("Made an allocation for argument %s", PrintValue(value).c_str());
362             log->Printf("  Data region    : %llx", (unsigned long long)address);
363             log->Printf("  Ref region     : %llx", (unsigned long long)data_address);
364         }
365 
366         return true;
367     }
368 
369     bool ResolveConstant (lldb::addr_t process_address, const Constant *constant)
370     {
371         APInt resolved_value;
372 
373         if (!ResolveConstantValue(resolved_value, constant))
374             return false;
375 
376         size_t constant_size = m_target_data.getTypeStoreSize(constant->getType());
377         lldb_private::DataBufferHeap buf(constant_size, 0);
378 
379         lldb_private::Error get_data_error;
380 
381         lldb_private::Scalar resolved_scalar(resolved_value.zextOrTrunc(llvm::NextPowerOf2(constant_size) * 8));
382         if (!resolved_scalar.GetAsMemoryData(buf.GetBytes(), buf.GetByteSize(), m_byte_order, get_data_error))
383             return false;
384 
385         lldb_private::Error write_error;
386 
387         m_execution_unit.WriteMemory(process_address, buf.GetBytes(), buf.GetByteSize(), write_error);
388 
389         return write_error.Success();
390     }
391 
392     lldb::addr_t Malloc (size_t size, uint8_t byte_alignment)
393     {
394         lldb::addr_t ret = m_stack_pointer;
395 
396         ret -= size;
397         ret -= (ret % byte_alignment);
398 
399         if (ret < m_frame_process_address)
400             return LLDB_INVALID_ADDRESS;
401 
402         m_stack_pointer = ret;
403         return ret;
404     }
405 
406     lldb::addr_t MallocPointer ()
407     {
408         return Malloc(m_target_data.getPointerSize(), m_target_data.getPointerPrefAlignment());
409     }
410 
411     lldb::addr_t Malloc (llvm::Type *type)
412     {
413         lldb_private::Error alloc_error;
414 
415         return Malloc(m_target_data.getTypeAllocSize(type), m_target_data.getPrefTypeAlignment(type));
416     }
417 
418     std::string PrintData (lldb::addr_t addr, llvm::Type *type)
419     {
420         size_t length = m_target_data.getTypeStoreSize(type);
421 
422         lldb_private::DataBufferHeap buf(length, 0);
423 
424         lldb_private::Error read_error;
425 
426         m_execution_unit.ReadMemory(buf.GetBytes(), addr, length, read_error);
427 
428         if (!read_error.Success())
429             return std::string("<couldn't read data>");
430 
431         lldb_private::StreamString ss;
432 
433         for (size_t i = 0; i < length; i++)
434         {
435             if ((!(i & 0xf)) && i)
436                 ss.Printf("%02hhx - ", buf.GetBytes()[i]);
437             else
438                 ss.Printf("%02hhx ", buf.GetBytes()[i]);
439         }
440 
441         return ss.GetString();
442     }
443 
444     lldb::addr_t ResolveValue (const Value *value, Module &module)
445     {
446         ValueMap::iterator i = m_values.find(value);
447 
448         if (i != m_values.end())
449             return i->second;
450 
451         // Fall back and allocate space [allocation type Alloca]
452 
453         lldb::addr_t data_address = Malloc(value->getType());
454 
455         if (const Constant *constant = dyn_cast<Constant>(value))
456         {
457             if (!ResolveConstant (data_address, constant))
458             {
459                 lldb_private::Error free_error;
460                 m_execution_unit.Free(data_address, free_error);
461                 return LLDB_INVALID_ADDRESS;
462             }
463         }
464 
465         m_values[value] = data_address;
466         return data_address;
467     }
468 };
469 
470 static const char *unsupported_opcode_error         = "Interpreter doesn't handle one of the expression's opcodes";
471 static const char *unsupported_operand_error        = "Interpreter doesn't handle one of the expression's operands";
472 //static const char *interpreter_initialization_error = "Interpreter couldn't be initialized";
473 static const char *interpreter_internal_error       = "Interpreter encountered an internal error";
474 static const char *bad_value_error                  = "Interpreter couldn't resolve a value during execution";
475 static const char *memory_allocation_error          = "Interpreter couldn't allocate memory";
476 static const char *memory_write_error               = "Interpreter couldn't write to memory";
477 static const char *memory_read_error                = "Interpreter couldn't read from memory";
478 static const char *infinite_loop_error              = "Interpreter ran for too many cycles";
479 //static const char *bad_result_error                 = "Result of expression is in bad memory";
480 
481 static bool
482 CanResolveConstant (llvm::Constant *constant)
483 {
484     switch (constant->getValueID())
485     {
486     default:
487         return false;
488     case Value::ConstantIntVal:
489     case Value::ConstantFPVal:
490     case Value::FunctionVal:
491         return true;
492     case Value::ConstantExprVal:
493         if (const ConstantExpr *constant_expr = dyn_cast<ConstantExpr>(constant))
494         {
495             switch (constant_expr->getOpcode())
496             {
497                 default:
498                     return false;
499                 case Instruction::IntToPtr:
500                 case Instruction::PtrToInt:
501                 case Instruction::BitCast:
502                     return CanResolveConstant(constant_expr->getOperand(0));
503                 case Instruction::GetElementPtr:
504                 {
505                     ConstantExpr::const_op_iterator op_cursor = constant_expr->op_begin();
506                     Constant *base = dyn_cast<Constant>(*op_cursor);
507                     if (!base)
508                         return false;
509 
510                     return CanResolveConstant(base);
511                 }
512             }
513         } else {
514             return false;
515         }
516     case Value::ConstantPointerNullVal:
517         return true;
518     }
519 }
520 
521 bool
522 IRInterpreter::CanInterpret (llvm::Module &module,
523                              llvm::Function &function,
524                              lldb_private::Error &error,
525                              const bool support_function_calls)
526 {
527     lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
528 
529     bool saw_function_with_body = false;
530 
531     for (Module::iterator fi = module.begin(), fe = module.end();
532          fi != fe;
533          ++fi)
534     {
535         if (fi->begin() != fi->end())
536         {
537             if (saw_function_with_body)
538                 return false;
539             saw_function_with_body = true;
540         }
541     }
542 
543     for (Function::iterator bbi = function.begin(), bbe = function.end();
544          bbi != bbe;
545          ++bbi)
546     {
547         for (BasicBlock::iterator ii = bbi->begin(), ie = bbi->end();
548              ii != ie;
549              ++ii)
550         {
551             switch (ii->getOpcode())
552             {
553             default:
554                 {
555                     if (log)
556                         log->Printf("Unsupported instruction: %s", PrintValue(&*ii).c_str());
557                     error.SetErrorToGenericError();
558                     error.SetErrorString(unsupported_opcode_error);
559                     return false;
560                 }
561             case Instruction::Add:
562             case Instruction::Alloca:
563             case Instruction::BitCast:
564             case Instruction::Br:
565                 break;
566             case Instruction::Call:
567                 {
568                     CallInst *call_inst = dyn_cast<CallInst>(ii);
569 
570                     if (!call_inst)
571                     {
572                         error.SetErrorToGenericError();
573                         error.SetErrorString(interpreter_internal_error);
574                         return false;
575                     }
576 
577                     if (!CanIgnoreCall(call_inst) && !support_function_calls)
578                     {
579                         if (log)
580                             log->Printf("Unsupported instruction: %s", PrintValue(&*ii).c_str());
581                         error.SetErrorToGenericError();
582                         error.SetErrorString(unsupported_opcode_error);
583                         return false;
584                     }
585                 }
586                 break;
587             case Instruction::GetElementPtr:
588                 break;
589             case Instruction::ICmp:
590                 {
591                     ICmpInst *icmp_inst = dyn_cast<ICmpInst>(ii);
592 
593                     if (!icmp_inst)
594                     {
595                         error.SetErrorToGenericError();
596                         error.SetErrorString(interpreter_internal_error);
597                         return false;
598                     }
599 
600                     switch (icmp_inst->getPredicate())
601                     {
602                     default:
603                     {
604                         if (log)
605                             log->Printf("Unsupported ICmp predicate: %s", PrintValue(&*ii).c_str());
606 
607                         error.SetErrorToGenericError();
608                         error.SetErrorString(unsupported_opcode_error);
609                         return false;
610                     }
611                     case CmpInst::ICMP_EQ:
612                     case CmpInst::ICMP_NE:
613                     case CmpInst::ICMP_UGT:
614                     case CmpInst::ICMP_UGE:
615                     case CmpInst::ICMP_ULT:
616                     case CmpInst::ICMP_ULE:
617                     case CmpInst::ICMP_SGT:
618                     case CmpInst::ICMP_SGE:
619                     case CmpInst::ICMP_SLT:
620                     case CmpInst::ICMP_SLE:
621                         break;
622                     }
623                 }
624                 break;
625             case Instruction::And:
626             case Instruction::AShr:
627             case Instruction::IntToPtr:
628             case Instruction::PtrToInt:
629             case Instruction::Load:
630             case Instruction::LShr:
631             case Instruction::Mul:
632             case Instruction::Or:
633             case Instruction::Ret:
634             case Instruction::SDiv:
635             case Instruction::SExt:
636             case Instruction::Shl:
637             case Instruction::SRem:
638             case Instruction::Store:
639             case Instruction::Sub:
640             case Instruction::Trunc:
641             case Instruction::UDiv:
642             case Instruction::URem:
643             case Instruction::Xor:
644             case Instruction::ZExt:
645                 break;
646             }
647 
648             for (int oi = 0, oe = ii->getNumOperands();
649                  oi != oe;
650                  ++oi)
651             {
652                 Value *operand = ii->getOperand(oi);
653                 Type *operand_type = operand->getType();
654 
655                 switch (operand_type->getTypeID())
656                 {
657                 default:
658                     break;
659                 case Type::VectorTyID:
660                     {
661                         if (log)
662                             log->Printf("Unsupported operand type: %s", PrintType(operand_type).c_str());
663                         error.SetErrorString(unsupported_operand_error);
664                         return false;
665                     }
666                 }
667 
668                 if (Constant *constant = llvm::dyn_cast<Constant>(operand))
669                 {
670                     if (!CanResolveConstant(constant))
671                     {
672                         if (log)
673                             log->Printf("Unsupported constant: %s", PrintValue(constant).c_str());
674                         error.SetErrorString(unsupported_operand_error);
675                         return false;
676                     }
677                 }
678             }
679         }
680 
681     }
682 
683     return true;}
684 
685 bool
686 IRInterpreter::Interpret (llvm::Module &module,
687                           llvm::Function &function,
688                           llvm::ArrayRef<lldb::addr_t> args,
689                           lldb_private::IRExecutionUnit &execution_unit,
690                           lldb_private::Error &error,
691                           lldb::addr_t stack_frame_bottom,
692                           lldb::addr_t stack_frame_top,
693                           lldb_private::ExecutionContext &exe_ctx)
694 {
695     lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
696 
697     if (log)
698     {
699         std::string s;
700         raw_string_ostream oss(s);
701 
702         module.print(oss, NULL);
703 
704         oss.flush();
705 
706         log->Printf("Module as passed in to IRInterpreter::Interpret: \n\"%s\"", s.c_str());
707     }
708 
709     DataLayout data_layout(&module);
710 
711     InterpreterStackFrame frame(data_layout, execution_unit, stack_frame_bottom, stack_frame_top);
712 
713     if (frame.m_frame_process_address == LLDB_INVALID_ADDRESS)
714     {
715         error.SetErrorString("Couldn't allocate stack frame");
716     }
717 
718     int arg_index = 0;
719 
720     for (llvm::Function::arg_iterator ai = function.arg_begin(), ae = function.arg_end();
721          ai != ae;
722          ++ai, ++arg_index)
723     {
724         if (args.size() <= static_cast<size_t>(arg_index))
725         {
726             error.SetErrorString ("Not enough arguments passed in to function");
727             return false;
728         }
729 
730         lldb::addr_t ptr = args[arg_index];
731 
732         frame.MakeArgument(&*ai, ptr);
733     }
734 
735     uint32_t num_insts = 0;
736 
737     frame.Jump(&function.front());
738 
739     while (frame.m_ii != frame.m_ie && (++num_insts < 4096))
740     {
741         const Instruction *inst = &*frame.m_ii;
742 
743         if (log)
744             log->Printf("Interpreting %s", PrintValue(inst).c_str());
745 
746         switch (inst->getOpcode())
747         {
748             default:
749                 break;
750 
751             case Instruction::Add:
752             case Instruction::Sub:
753             case Instruction::Mul:
754             case Instruction::SDiv:
755             case Instruction::UDiv:
756             case Instruction::SRem:
757             case Instruction::URem:
758             case Instruction::Shl:
759             case Instruction::LShr:
760             case Instruction::AShr:
761             case Instruction::And:
762             case Instruction::Or:
763             case Instruction::Xor:
764             {
765                 const BinaryOperator *bin_op = dyn_cast<BinaryOperator>(inst);
766 
767                 if (!bin_op)
768                 {
769                     if (log)
770                         log->Printf("getOpcode() returns %s, but instruction is not a BinaryOperator", inst->getOpcodeName());
771                     error.SetErrorToGenericError();
772                     error.SetErrorString(interpreter_internal_error);
773                     return false;
774                 }
775 
776                 Value *lhs = inst->getOperand(0);
777                 Value *rhs = inst->getOperand(1);
778 
779                 lldb_private::Scalar L;
780                 lldb_private::Scalar R;
781 
782                 if (!frame.EvaluateValue(L, lhs, module))
783                 {
784                     if (log)
785                         log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
786                     error.SetErrorToGenericError();
787                     error.SetErrorString(bad_value_error);
788                     return false;
789                 }
790 
791                 if (!frame.EvaluateValue(R, rhs, module))
792                 {
793                     if (log)
794                         log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
795                     error.SetErrorToGenericError();
796                     error.SetErrorString(bad_value_error);
797                     return false;
798                 }
799 
800                 lldb_private::Scalar result;
801 
802                 switch (inst->getOpcode())
803                 {
804                     default:
805                         break;
806                     case Instruction::Add:
807                         result = L + R;
808                         break;
809                     case Instruction::Mul:
810                         result = L * R;
811                         break;
812                     case Instruction::Sub:
813                         result = L - R;
814                         break;
815                     case Instruction::SDiv:
816                         L.MakeSigned();
817                         R.MakeSigned();
818                         result = L / R;
819                         break;
820                     case Instruction::UDiv:
821                         L.MakeUnsigned();
822                         R.MakeUnsigned();
823                         result = L / R;
824                         break;
825                     case Instruction::SRem:
826                         L.MakeSigned();
827                         R.MakeSigned();
828                         result = L % R;
829                         break;
830                     case Instruction::URem:
831                         L.MakeUnsigned();
832                         R.MakeUnsigned();
833                         result = L % R;
834                         break;
835                     case Instruction::Shl:
836                         result = L << R;
837                         break;
838                     case Instruction::AShr:
839                         result = L >> R;
840                         break;
841                     case Instruction::LShr:
842                         result = L;
843                         result.ShiftRightLogical(R);
844                         break;
845                     case Instruction::And:
846                         result = L & R;
847                         break;
848                     case Instruction::Or:
849                         result = L | R;
850                         break;
851                     case Instruction::Xor:
852                         result = L ^ R;
853                         break;
854                 }
855 
856                 frame.AssignValue(inst, result, module);
857 
858                 if (log)
859                 {
860                     log->Printf("Interpreted a %s", inst->getOpcodeName());
861                     log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
862                     log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
863                     log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
864                 }
865             }
866                 break;
867             case Instruction::Alloca:
868             {
869                 const AllocaInst *alloca_inst = dyn_cast<AllocaInst>(inst);
870 
871                 if (!alloca_inst)
872                 {
873                     if (log)
874                         log->Printf("getOpcode() returns Alloca, but instruction is not an AllocaInst");
875                     error.SetErrorToGenericError();
876                     error.SetErrorString(interpreter_internal_error);
877                     return false;
878                 }
879 
880                 if (alloca_inst->isArrayAllocation())
881                 {
882                     if (log)
883                         log->Printf("AllocaInsts are not handled if isArrayAllocation() is true");
884                     error.SetErrorToGenericError();
885                     error.SetErrorString(unsupported_opcode_error);
886                     return false;
887                 }
888 
889                 // The semantics of Alloca are:
890                 //   Create a region R of virtual memory of type T, backed by a data buffer
891                 //   Create a region P of virtual memory of type T*, backed by a data buffer
892                 //   Write the virtual address of R into P
893 
894                 Type *T = alloca_inst->getAllocatedType();
895                 Type *Tptr = alloca_inst->getType();
896 
897                 lldb::addr_t R = frame.Malloc(T);
898 
899                 if (R == LLDB_INVALID_ADDRESS)
900                 {
901                     if (log)
902                         log->Printf("Couldn't allocate memory for an AllocaInst");
903                     error.SetErrorToGenericError();
904                     error.SetErrorString(memory_allocation_error);
905                     return false;
906                 }
907 
908                 lldb::addr_t P = frame.Malloc(Tptr);
909 
910                 if (P == LLDB_INVALID_ADDRESS)
911                 {
912                     if (log)
913                         log->Printf("Couldn't allocate the result pointer for an AllocaInst");
914                     error.SetErrorToGenericError();
915                     error.SetErrorString(memory_allocation_error);
916                     return false;
917                 }
918 
919                 lldb_private::Error write_error;
920 
921                 execution_unit.WritePointerToMemory(P, R, write_error);
922 
923                 if (!write_error.Success())
924                 {
925                     if (log)
926                         log->Printf("Couldn't write the result pointer for an AllocaInst");
927                     error.SetErrorToGenericError();
928                     error.SetErrorString(memory_write_error);
929                     lldb_private::Error free_error;
930                     execution_unit.Free(P, free_error);
931                     execution_unit.Free(R, free_error);
932                     return false;
933                 }
934 
935                 frame.m_values[alloca_inst] = P;
936 
937                 if (log)
938                 {
939                     log->Printf("Interpreted an AllocaInst");
940                     log->Printf("  R : 0x%" PRIx64, R);
941                     log->Printf("  P : 0x%" PRIx64, P);
942                 }
943             }
944                 break;
945             case Instruction::BitCast:
946             case Instruction::ZExt:
947             {
948                 const CastInst *cast_inst = dyn_cast<CastInst>(inst);
949 
950                 if (!cast_inst)
951                 {
952                     if (log)
953                         log->Printf("getOpcode() returns %s, but instruction is not a BitCastInst", cast_inst->getOpcodeName());
954                     error.SetErrorToGenericError();
955                     error.SetErrorString(interpreter_internal_error);
956                     return false;
957                 }
958 
959                 Value *source = cast_inst->getOperand(0);
960 
961                 lldb_private::Scalar S;
962 
963                 if (!frame.EvaluateValue(S, source, module))
964                 {
965                     if (log)
966                         log->Printf("Couldn't evaluate %s", PrintValue(source).c_str());
967                     error.SetErrorToGenericError();
968                     error.SetErrorString(bad_value_error);
969                     return false;
970                 }
971 
972                 frame.AssignValue(inst, S, module);
973             }
974                 break;
975             case Instruction::SExt:
976             {
977                 const CastInst *cast_inst = dyn_cast<CastInst>(inst);
978 
979                 if (!cast_inst)
980                 {
981                     if (log)
982                         log->Printf("getOpcode() returns %s, but instruction is not a BitCastInst", cast_inst->getOpcodeName());
983                     error.SetErrorToGenericError();
984                     error.SetErrorString(interpreter_internal_error);
985                     return false;
986                 }
987 
988                 Value *source = cast_inst->getOperand(0);
989 
990                 lldb_private::Scalar S;
991 
992                 if (!frame.EvaluateValue(S, source, module))
993                 {
994                     if (log)
995                         log->Printf("Couldn't evaluate %s", PrintValue(source).c_str());
996                     error.SetErrorToGenericError();
997                     error.SetErrorString(bad_value_error);
998                     return false;
999                 }
1000 
1001                 S.MakeSigned();
1002 
1003                 lldb_private::Scalar S_signextend(S.SLongLong());
1004 
1005                 frame.AssignValue(inst, S_signextend, module);
1006             }
1007                 break;
1008             case Instruction::Br:
1009             {
1010                 const BranchInst *br_inst = dyn_cast<BranchInst>(inst);
1011 
1012                 if (!br_inst)
1013                 {
1014                     if (log)
1015                         log->Printf("getOpcode() returns Br, but instruction is not a BranchInst");
1016                     error.SetErrorToGenericError();
1017                     error.SetErrorString(interpreter_internal_error);
1018                     return false;
1019                 }
1020 
1021                 if (br_inst->isConditional())
1022                 {
1023                     Value *condition = br_inst->getCondition();
1024 
1025                     lldb_private::Scalar C;
1026 
1027                     if (!frame.EvaluateValue(C, condition, module))
1028                     {
1029                         if (log)
1030                             log->Printf("Couldn't evaluate %s", PrintValue(condition).c_str());
1031                         error.SetErrorToGenericError();
1032                         error.SetErrorString(bad_value_error);
1033                         return false;
1034                     }
1035 
1036                     if (!C.IsZero())
1037                         frame.Jump(br_inst->getSuccessor(0));
1038                     else
1039                         frame.Jump(br_inst->getSuccessor(1));
1040 
1041                     if (log)
1042                     {
1043                         log->Printf("Interpreted a BrInst with a condition");
1044                         log->Printf("  cond : %s", frame.SummarizeValue(condition).c_str());
1045                     }
1046                 }
1047                 else
1048                 {
1049                     frame.Jump(br_inst->getSuccessor(0));
1050 
1051                     if (log)
1052                     {
1053                         log->Printf("Interpreted a BrInst with no condition");
1054                     }
1055                 }
1056             }
1057                 continue;
1058             case Instruction::GetElementPtr:
1059             {
1060                 const GetElementPtrInst *gep_inst = dyn_cast<GetElementPtrInst>(inst);
1061 
1062                 if (!gep_inst)
1063                 {
1064                     if (log)
1065                         log->Printf("getOpcode() returns GetElementPtr, but instruction is not a GetElementPtrInst");
1066                     error.SetErrorToGenericError();
1067                     error.SetErrorString(interpreter_internal_error);
1068                     return false;
1069                 }
1070 
1071                 const Value *pointer_operand = gep_inst->getPointerOperand();
1072                 Type *src_elem_ty = gep_inst->getSourceElementType();
1073 
1074                 lldb_private::Scalar P;
1075 
1076                 if (!frame.EvaluateValue(P, pointer_operand, module))
1077                 {
1078                     if (log)
1079                         log->Printf("Couldn't evaluate %s", PrintValue(pointer_operand).c_str());
1080                     error.SetErrorToGenericError();
1081                     error.SetErrorString(bad_value_error);
1082                     return false;
1083                 }
1084 
1085                 typedef SmallVector <Value *, 8> IndexVector;
1086                 typedef IndexVector::iterator IndexIterator;
1087 
1088                 SmallVector <Value *, 8> indices (gep_inst->idx_begin(),
1089                                                   gep_inst->idx_end());
1090 
1091                 SmallVector <Value *, 8> const_indices;
1092 
1093                 for (IndexIterator ii = indices.begin(), ie = indices.end();
1094                      ii != ie;
1095                      ++ii)
1096                 {
1097                     ConstantInt *constant_index = dyn_cast<ConstantInt>(*ii);
1098 
1099                     if (!constant_index)
1100                     {
1101                         lldb_private::Scalar I;
1102 
1103                         if (!frame.EvaluateValue(I, *ii, module))
1104                         {
1105                             if (log)
1106                                 log->Printf("Couldn't evaluate %s", PrintValue(*ii).c_str());
1107                             error.SetErrorToGenericError();
1108                             error.SetErrorString(bad_value_error);
1109                             return false;
1110                         }
1111 
1112                         if (log)
1113                             log->Printf("Evaluated constant index %s as %llu", PrintValue(*ii).c_str(), I.ULongLong(LLDB_INVALID_ADDRESS));
1114 
1115                         constant_index = cast<ConstantInt>(ConstantInt::get((*ii)->getType(), I.ULongLong(LLDB_INVALID_ADDRESS)));
1116                     }
1117 
1118                     const_indices.push_back(constant_index);
1119                 }
1120 
1121                 uint64_t offset = data_layout.getIndexedOffsetInType(src_elem_ty, const_indices);
1122 
1123                 lldb_private::Scalar Poffset = P + offset;
1124 
1125                 frame.AssignValue(inst, Poffset, module);
1126 
1127                 if (log)
1128                 {
1129                     log->Printf("Interpreted a GetElementPtrInst");
1130                     log->Printf("  P       : %s", frame.SummarizeValue(pointer_operand).c_str());
1131                     log->Printf("  Poffset : %s", frame.SummarizeValue(inst).c_str());
1132                 }
1133             }
1134                 break;
1135             case Instruction::ICmp:
1136             {
1137                 const ICmpInst *icmp_inst = dyn_cast<ICmpInst>(inst);
1138 
1139                 if (!icmp_inst)
1140                 {
1141                     if (log)
1142                         log->Printf("getOpcode() returns ICmp, but instruction is not an ICmpInst");
1143                     error.SetErrorToGenericError();
1144                     error.SetErrorString(interpreter_internal_error);
1145                     return false;
1146                 }
1147 
1148                 CmpInst::Predicate predicate = icmp_inst->getPredicate();
1149 
1150                 Value *lhs = inst->getOperand(0);
1151                 Value *rhs = inst->getOperand(1);
1152 
1153                 lldb_private::Scalar L;
1154                 lldb_private::Scalar R;
1155 
1156                 if (!frame.EvaluateValue(L, lhs, module))
1157                 {
1158                     if (log)
1159                         log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
1160                     error.SetErrorToGenericError();
1161                     error.SetErrorString(bad_value_error);
1162                     return false;
1163                 }
1164 
1165                 if (!frame.EvaluateValue(R, rhs, module))
1166                 {
1167                     if (log)
1168                         log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
1169                     error.SetErrorToGenericError();
1170                     error.SetErrorString(bad_value_error);
1171                     return false;
1172                 }
1173 
1174                 lldb_private::Scalar result;
1175 
1176                 switch (predicate)
1177                 {
1178                     default:
1179                         return false;
1180                     case CmpInst::ICMP_EQ:
1181                         result = (L == R);
1182                         break;
1183                     case CmpInst::ICMP_NE:
1184                         result = (L != R);
1185                         break;
1186                     case CmpInst::ICMP_UGT:
1187                         L.MakeUnsigned();
1188                         R.MakeUnsigned();
1189                         result = (L > R);
1190                         break;
1191                     case CmpInst::ICMP_UGE:
1192                         L.MakeUnsigned();
1193                         R.MakeUnsigned();
1194                         result = (L >= R);
1195                         break;
1196                     case CmpInst::ICMP_ULT:
1197                         L.MakeUnsigned();
1198                         R.MakeUnsigned();
1199                         result = (L < R);
1200                         break;
1201                     case CmpInst::ICMP_ULE:
1202                         L.MakeUnsigned();
1203                         R.MakeUnsigned();
1204                         result = (L <= R);
1205                         break;
1206                     case CmpInst::ICMP_SGT:
1207                         L.MakeSigned();
1208                         R.MakeSigned();
1209                         result = (L > R);
1210                         break;
1211                     case CmpInst::ICMP_SGE:
1212                         L.MakeSigned();
1213                         R.MakeSigned();
1214                         result = (L >= R);
1215                         break;
1216                     case CmpInst::ICMP_SLT:
1217                         L.MakeSigned();
1218                         R.MakeSigned();
1219                         result = (L < R);
1220                         break;
1221                     case CmpInst::ICMP_SLE:
1222                         L.MakeSigned();
1223                         R.MakeSigned();
1224                         result = (L <= R);
1225                         break;
1226                 }
1227 
1228                 frame.AssignValue(inst, result, module);
1229 
1230                 if (log)
1231                 {
1232                     log->Printf("Interpreted an ICmpInst");
1233                     log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
1234                     log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
1235                     log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
1236                 }
1237             }
1238                 break;
1239             case Instruction::IntToPtr:
1240             {
1241                 const IntToPtrInst *int_to_ptr_inst = dyn_cast<IntToPtrInst>(inst);
1242 
1243                 if (!int_to_ptr_inst)
1244                 {
1245                     if (log)
1246                         log->Printf("getOpcode() returns IntToPtr, but instruction is not an IntToPtrInst");
1247                     error.SetErrorToGenericError();
1248                     error.SetErrorString(interpreter_internal_error);
1249                     return false;
1250                 }
1251 
1252                 Value *src_operand = int_to_ptr_inst->getOperand(0);
1253 
1254                 lldb_private::Scalar I;
1255 
1256                 if (!frame.EvaluateValue(I, src_operand, module))
1257                 {
1258                     if (log)
1259                         log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
1260                     error.SetErrorToGenericError();
1261                     error.SetErrorString(bad_value_error);
1262                     return false;
1263                 }
1264 
1265                 frame.AssignValue(inst, I, module);
1266 
1267                 if (log)
1268                 {
1269                     log->Printf("Interpreted an IntToPtr");
1270                     log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1271                     log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1272                 }
1273             }
1274                 break;
1275             case Instruction::PtrToInt:
1276             {
1277                 const PtrToIntInst *ptr_to_int_inst = dyn_cast<PtrToIntInst>(inst);
1278 
1279                 if (!ptr_to_int_inst)
1280                 {
1281                     if (log)
1282                         log->Printf("getOpcode() returns PtrToInt, but instruction is not an PtrToIntInst");
1283                     error.SetErrorToGenericError();
1284                     error.SetErrorString(interpreter_internal_error);
1285                     return false;
1286                 }
1287 
1288                 Value *src_operand = ptr_to_int_inst->getOperand(0);
1289 
1290                 lldb_private::Scalar I;
1291 
1292                 if (!frame.EvaluateValue(I, src_operand, module))
1293                 {
1294                     if (log)
1295                         log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
1296                     error.SetErrorToGenericError();
1297                     error.SetErrorString(bad_value_error);
1298                     return false;
1299                 }
1300 
1301                 frame.AssignValue(inst, I, module);
1302 
1303                 if (log)
1304                 {
1305                     log->Printf("Interpreted a PtrToInt");
1306                     log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1307                     log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1308                 }
1309             }
1310                 break;
1311             case Instruction::Trunc:
1312             {
1313                 const TruncInst *trunc_inst = dyn_cast<TruncInst>(inst);
1314 
1315                 if (!trunc_inst)
1316                 {
1317                     if (log)
1318                         log->Printf("getOpcode() returns Trunc, but instruction is not a TruncInst");
1319                     error.SetErrorToGenericError();
1320                     error.SetErrorString(interpreter_internal_error);
1321                     return false;
1322                 }
1323 
1324                 Value *src_operand = trunc_inst->getOperand(0);
1325 
1326                 lldb_private::Scalar I;
1327 
1328                 if (!frame.EvaluateValue(I, src_operand, module))
1329                 {
1330                     if (log)
1331                         log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
1332                     error.SetErrorToGenericError();
1333                     error.SetErrorString(bad_value_error);
1334                     return false;
1335                 }
1336 
1337                 frame.AssignValue(inst, I, module);
1338 
1339                 if (log)
1340                 {
1341                     log->Printf("Interpreted a Trunc");
1342                     log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1343                     log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1344                 }
1345             }
1346                 break;
1347             case Instruction::Load:
1348             {
1349                 const LoadInst *load_inst = dyn_cast<LoadInst>(inst);
1350 
1351                 if (!load_inst)
1352                 {
1353                     if (log)
1354                         log->Printf("getOpcode() returns Load, but instruction is not a LoadInst");
1355                     error.SetErrorToGenericError();
1356                     error.SetErrorString(interpreter_internal_error);
1357                     return false;
1358                 }
1359 
1360                 // The semantics of Load are:
1361                 //   Create a region D that will contain the loaded data
1362                 //   Resolve the region P containing a pointer
1363                 //   Dereference P to get the region R that the data should be loaded from
1364                 //   Transfer a unit of type type(D) from R to D
1365 
1366                 const Value *pointer_operand = load_inst->getPointerOperand();
1367 
1368                 Type *pointer_ty = pointer_operand->getType();
1369                 PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1370                 if (!pointer_ptr_ty)
1371                 {
1372                     if (log)
1373                         log->Printf("getPointerOperand()->getType() is not a PointerType");
1374                     error.SetErrorToGenericError();
1375                     error.SetErrorString(interpreter_internal_error);
1376                     return false;
1377                 }
1378                 Type *target_ty = pointer_ptr_ty->getElementType();
1379 
1380                 lldb::addr_t D = frame.ResolveValue(load_inst, module);
1381                 lldb::addr_t P = frame.ResolveValue(pointer_operand, module);
1382 
1383                 if (D == LLDB_INVALID_ADDRESS)
1384                 {
1385                     if (log)
1386                         log->Printf("LoadInst's value doesn't resolve to anything");
1387                     error.SetErrorToGenericError();
1388                     error.SetErrorString(bad_value_error);
1389                     return false;
1390                 }
1391 
1392                 if (P == LLDB_INVALID_ADDRESS)
1393                 {
1394                     if (log)
1395                         log->Printf("LoadInst's pointer doesn't resolve to anything");
1396                     error.SetErrorToGenericError();
1397                     error.SetErrorString(bad_value_error);
1398                     return false;
1399                 }
1400 
1401                 lldb::addr_t R;
1402                 lldb_private::Error read_error;
1403                 execution_unit.ReadPointerFromMemory(&R, P, read_error);
1404 
1405                 if (!read_error.Success())
1406                 {
1407                     if (log)
1408                         log->Printf("Couldn't read the address to be loaded for a LoadInst");
1409                     error.SetErrorToGenericError();
1410                     error.SetErrorString(memory_read_error);
1411                     return false;
1412                 }
1413 
1414                 size_t target_size = data_layout.getTypeStoreSize(target_ty);
1415                 lldb_private::DataBufferHeap buffer(target_size, 0);
1416 
1417                 read_error.Clear();
1418                 execution_unit.ReadMemory(buffer.GetBytes(), R, buffer.GetByteSize(), read_error);
1419                 if (!read_error.Success())
1420                 {
1421                     if (log)
1422                         log->Printf("Couldn't read from a region on behalf of a LoadInst");
1423                     error.SetErrorToGenericError();
1424                     error.SetErrorString(memory_read_error);
1425                     return false;
1426                 }
1427 
1428                 lldb_private::Error write_error;
1429                 execution_unit.WriteMemory(D, buffer.GetBytes(), buffer.GetByteSize(), write_error);
1430                 if (!write_error.Success())
1431                 {
1432                     if (log)
1433                         log->Printf("Couldn't write to a region on behalf of a LoadInst");
1434                     error.SetErrorToGenericError();
1435                     error.SetErrorString(memory_read_error);
1436                     return false;
1437                 }
1438 
1439                 if (log)
1440                 {
1441                     log->Printf("Interpreted a LoadInst");
1442                     log->Printf("  P : 0x%" PRIx64, P);
1443                     log->Printf("  R : 0x%" PRIx64, R);
1444                     log->Printf("  D : 0x%" PRIx64, D);
1445                 }
1446             }
1447                 break;
1448             case Instruction::Ret:
1449             {
1450                 return true;
1451             }
1452             case Instruction::Store:
1453             {
1454                 const StoreInst *store_inst = dyn_cast<StoreInst>(inst);
1455 
1456                 if (!store_inst)
1457                 {
1458                     if (log)
1459                         log->Printf("getOpcode() returns Store, but instruction is not a StoreInst");
1460                     error.SetErrorToGenericError();
1461                     error.SetErrorString(interpreter_internal_error);
1462                     return false;
1463                 }
1464 
1465                 // The semantics of Store are:
1466                 //   Resolve the region D containing the data to be stored
1467                 //   Resolve the region P containing a pointer
1468                 //   Dereference P to get the region R that the data should be stored in
1469                 //   Transfer a unit of type type(D) from D to R
1470 
1471                 const Value *value_operand = store_inst->getValueOperand();
1472                 const Value *pointer_operand = store_inst->getPointerOperand();
1473 
1474                 Type *pointer_ty = pointer_operand->getType();
1475                 PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1476                 if (!pointer_ptr_ty)
1477                     return false;
1478                 Type *target_ty = pointer_ptr_ty->getElementType();
1479 
1480                 lldb::addr_t D = frame.ResolveValue(value_operand, module);
1481                 lldb::addr_t P = frame.ResolveValue(pointer_operand, module);
1482 
1483                 if (D == LLDB_INVALID_ADDRESS)
1484                 {
1485                     if (log)
1486                         log->Printf("StoreInst's value doesn't resolve to anything");
1487                     error.SetErrorToGenericError();
1488                     error.SetErrorString(bad_value_error);
1489                     return false;
1490                 }
1491 
1492                 if (P == LLDB_INVALID_ADDRESS)
1493                 {
1494                     if (log)
1495                         log->Printf("StoreInst's pointer doesn't resolve to anything");
1496                     error.SetErrorToGenericError();
1497                     error.SetErrorString(bad_value_error);
1498                     return false;
1499                 }
1500 
1501                 lldb::addr_t R;
1502                 lldb_private::Error read_error;
1503                 execution_unit.ReadPointerFromMemory(&R, P, read_error);
1504 
1505                 if (!read_error.Success())
1506                 {
1507                     if (log)
1508                         log->Printf("Couldn't read the address to be loaded for a LoadInst");
1509                     error.SetErrorToGenericError();
1510                     error.SetErrorString(memory_read_error);
1511                     return false;
1512                 }
1513 
1514                 size_t target_size = data_layout.getTypeStoreSize(target_ty);
1515                 lldb_private::DataBufferHeap buffer(target_size, 0);
1516 
1517                 read_error.Clear();
1518                 execution_unit.ReadMemory(buffer.GetBytes(), D, buffer.GetByteSize(), read_error);
1519                 if (!read_error.Success())
1520                 {
1521                     if (log)
1522                         log->Printf("Couldn't read from a region on behalf of a StoreInst");
1523                     error.SetErrorToGenericError();
1524                     error.SetErrorString(memory_read_error);
1525                     return false;
1526                 }
1527 
1528                 lldb_private::Error write_error;
1529                 execution_unit.WriteMemory(R, buffer.GetBytes(), buffer.GetByteSize(), write_error);
1530                 if (!write_error.Success())
1531                 {
1532                     if (log)
1533                         log->Printf("Couldn't write to a region on behalf of a StoreInst");
1534                     error.SetErrorToGenericError();
1535                     error.SetErrorString(memory_write_error);
1536                     return false;
1537                 }
1538 
1539                 if (log)
1540                 {
1541                     log->Printf("Interpreted a StoreInst");
1542                     log->Printf("  D : 0x%" PRIx64, D);
1543                     log->Printf("  P : 0x%" PRIx64, P);
1544                     log->Printf("  R : 0x%" PRIx64, R);
1545                 }
1546             }
1547                 break;
1548             case Instruction::Call:
1549             {
1550                 const CallInst *call_inst = dyn_cast<CallInst>(inst);
1551 
1552                 if (!call_inst)
1553                 {
1554                     if (log)
1555                        log->Printf("getOpcode() returns %s, but instruction is not a CallInst", inst->getOpcodeName());
1556                     error.SetErrorToGenericError();
1557                     error.SetErrorString(interpreter_internal_error);
1558                     return false;
1559                 }
1560 
1561                 if (CanIgnoreCall(call_inst))
1562                     break;
1563 
1564                 // Get the return type
1565                 llvm::Type *returnType = call_inst->getType();
1566                 if (returnType == nullptr)
1567                 {
1568                     error.SetErrorToGenericError();
1569                     error.SetErrorString("unable to access return type");
1570                     return false;
1571                 }
1572 
1573                 // Work with void, integer and pointer return types
1574                 if (!returnType->isVoidTy() &&
1575                     !returnType->isIntegerTy() &&
1576                     !returnType->isPointerTy())
1577                 {
1578                     error.SetErrorToGenericError();
1579                     error.SetErrorString("return type is not supported");
1580                     return false;
1581                 }
1582 
1583                 // Check we can actually get a thread
1584                 if (exe_ctx.GetThreadPtr() == nullptr)
1585                 {
1586                     error.SetErrorToGenericError();
1587                     error.SetErrorStringWithFormat("unable to acquire thread");
1588                     return false;
1589                 }
1590 
1591                 // Make sure we have a valid process
1592                 if (!exe_ctx.GetProcessPtr())
1593                 {
1594                     error.SetErrorToGenericError();
1595                     error.SetErrorStringWithFormat("unable to get the process");
1596                     return false;
1597                 }
1598 
1599                 // Find the address of the callee function
1600                 lldb_private::Scalar I;
1601                 const llvm::Value *val = call_inst->getCalledValue();
1602 
1603                 if (!frame.EvaluateValue(I, val, module))
1604                 {
1605                     error.SetErrorToGenericError();
1606                     error.SetErrorString("unable to get address of function");
1607                     return false;
1608                 }
1609                 lldb_private::Address funcAddr(I.ULongLong(LLDB_INVALID_ADDRESS));
1610 
1611                 lldb_private::DiagnosticManager diagnostics;
1612                 lldb_private::EvaluateExpressionOptions options;
1613 
1614                 // We generally receive a function pointer which we must dereference
1615                 llvm::Type* prototype = val->getType();
1616                 if (!prototype->isPointerTy())
1617                 {
1618                     error.SetErrorToGenericError();
1619                     error.SetErrorString("call need function pointer");
1620                     return false;
1621                 }
1622 
1623                 // Dereference the function pointer
1624                 prototype = prototype->getPointerElementType();
1625                 if (!(prototype->isFunctionTy() || prototype->isFunctionVarArg()))
1626                 {
1627                     error.SetErrorToGenericError();
1628                     error.SetErrorString("call need function pointer");
1629                     return false;
1630                 }
1631 
1632                 // Find number of arguments
1633                 const int numArgs = call_inst->getNumArgOperands();
1634 
1635                 // We work with a fixed array of 16 arguments which is our upper limit
1636                 static lldb_private::ABI::CallArgument rawArgs[16];
1637                 if (numArgs >= 16)
1638                 {
1639                     error.SetErrorToGenericError();
1640                     error.SetErrorStringWithFormat("function takes too many arguments");
1641                     return false;
1642                 }
1643 
1644                 // Push all function arguments to the argument list that will
1645                 // be passed to the call function thread plan
1646                 for (int i = 0; i < numArgs; i++)
1647                 {
1648                     // Get details of this argument
1649                     llvm::Value *arg_op = call_inst->getArgOperand(i);
1650                     llvm::Type  *arg_ty = arg_op->getType();
1651 
1652                     // Ensure that this argument is an supported type
1653                     if (!arg_ty->isIntegerTy() && !arg_ty->isPointerTy())
1654                     {
1655                          error.SetErrorToGenericError();
1656                          error.SetErrorStringWithFormat("argument %d must be integer type", i);
1657                          return false;
1658                     }
1659 
1660                     // Extract the arguments value
1661                     lldb_private::Scalar tmp_op = 0;
1662                     if (!frame.EvaluateValue(tmp_op, arg_op, module))
1663                     {
1664                          error.SetErrorToGenericError();
1665                          error.SetErrorStringWithFormat("unable to evaluate argument %d", i);
1666                          return false;
1667                     }
1668 
1669                     // Check if this is a string literal or constant string pointer
1670                     if (arg_ty->isPointerTy())
1671                     {
1672                         // Pointer to just one type
1673                         assert(arg_ty->getNumContainedTypes() == 1);
1674 
1675                         lldb::addr_t addr = tmp_op.ULongLong();
1676                         size_t dataSize = 0;
1677 
1678                         if (execution_unit.GetAllocSize(addr, dataSize))
1679                         {
1680                             // Create the required buffer
1681                             rawArgs[i].size = dataSize;
1682                             rawArgs[i].data_ap.reset(new uint8_t[dataSize + 1]);
1683 
1684                             // Read string from host memory
1685                             execution_unit.ReadMemory(rawArgs[i].data_ap.get(), addr, dataSize, error);
1686                             if (error.Fail())
1687                             {
1688                                 assert(!"we have failed to read the string from memory");
1689                                 return false;
1690                             }
1691                             // Add null terminator
1692                             rawArgs[i].data_ap[dataSize] = '\0';
1693                             rawArgs[i].type = lldb_private::ABI::CallArgument::HostPointer;
1694                         }
1695                         else
1696                         {
1697                             assert(!"unable to locate host data for transfer to device");
1698                             return false;
1699                         }
1700                     }
1701                     else /* if ( arg_ty->isPointerTy() ) */
1702                     {
1703                         rawArgs[i].type = lldb_private::ABI::CallArgument::TargetValue;
1704                         // Get argument size in bytes
1705                         rawArgs[i].size = arg_ty->getIntegerBitWidth() / 8;
1706                         // Push value into argument list for thread plan
1707                         rawArgs[i].value = tmp_op.ULongLong();
1708                     }
1709 
1710                 }
1711 
1712                 // Pack the arguments into an llvm::array
1713                 llvm::ArrayRef<lldb_private::ABI::CallArgument> args(rawArgs, numArgs);
1714 
1715                 // Setup a thread plan to call the target function
1716                 lldb::ThreadPlanSP call_plan_sp(new lldb_private::ThreadPlanCallFunctionUsingABI(
1717                     exe_ctx.GetThreadRef(), funcAddr, *prototype, *returnType, args, options));
1718 
1719                 // Check if the plan is valid
1720                 lldb_private::StreamString ss;
1721                 if (!call_plan_sp || !call_plan_sp->ValidatePlan(&ss))
1722                 {
1723                     error.SetErrorToGenericError();
1724                     error.SetErrorStringWithFormat("unable to make ThreadPlanCallFunctionUsingABI for 0x%llx",
1725                                                    I.ULongLong());
1726                     return false;
1727                 }
1728 
1729                 exe_ctx.GetProcessPtr()->SetRunningUserExpression(true);
1730 
1731                 // Execute the actual function call thread plan
1732                 lldb::ExpressionResults res =
1733                     exe_ctx.GetProcessRef().RunThreadPlan(exe_ctx, call_plan_sp, options, diagnostics);
1734 
1735                 // Check that the thread plan completed successfully
1736                 if (res != lldb::ExpressionResults::eExpressionCompleted)
1737                 {
1738                     error.SetErrorToGenericError();
1739                     error.SetErrorStringWithFormat("ThreadPlanCallFunctionUsingABI failed");
1740                     return false;
1741                 }
1742 
1743                 exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
1744 
1745                 // Void return type
1746                 if (returnType->isVoidTy())
1747                 {
1748                     // Cant assign to void types, so we leave the frame untouched
1749                 }
1750                 else
1751                     // Integer or pointer return type
1752                     if (returnType->isIntegerTy() || returnType->isPointerTy())
1753                     {
1754                         // Get the encapsulated return value
1755                         lldb::ValueObjectSP retVal = call_plan_sp.get()->GetReturnValueObject();
1756 
1757                         lldb_private::Scalar returnVal = -1;
1758                         lldb_private::ValueObject *vobj = retVal.get();
1759 
1760                         // Check if the return value is valid
1761                         if (vobj == nullptr || retVal.empty())
1762                         {
1763                             error.SetErrorToGenericError();
1764                             error.SetErrorStringWithFormat("unable to get the return value");
1765                             return false;
1766                         }
1767 
1768                         // Extract the return value as a integer
1769                         lldb_private::Value & value = vobj->GetValue();
1770                         returnVal = value.GetScalar();
1771 
1772                         // Push the return value as the result
1773                         frame.AssignValue(inst, returnVal, module);
1774                     }
1775             }
1776                 break;
1777         }
1778 
1779         ++frame.m_ii;
1780     }
1781 
1782     if (num_insts >= 4096)
1783     {
1784         error.SetErrorToGenericError();
1785         error.SetErrorString(infinite_loop_error);
1786         return false;
1787     }
1788 
1789     return false;
1790 }
1791