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.GetRawBits64(0), 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         lldb_private::StreamString buffer (lldb_private::Stream::eBinary,
377                                            m_execution_unit.GetAddressByteSize(),
378                                            m_execution_unit.GetByteOrder());
379 
380         size_t constant_size = m_target_data.getTypeStoreSize(constant->getType());
381 
382         const uint64_t *raw_data = resolved_value.getRawData();
383 
384         buffer.PutRawBytes(raw_data, constant_size, lldb_private::endian::InlHostByteOrder());
385 
386         lldb_private::Error write_error;
387 
388         m_execution_unit.WriteMemory(process_address, (const uint8_t*)buffer.GetData(), constant_size, write_error);
389 
390         return write_error.Success();
391     }
392 
393     lldb::addr_t Malloc (size_t size, uint8_t byte_alignment)
394     {
395         lldb::addr_t ret = m_stack_pointer;
396 
397         ret -= size;
398         ret -= (ret % byte_alignment);
399 
400         if (ret < m_frame_process_address)
401             return LLDB_INVALID_ADDRESS;
402 
403         m_stack_pointer = ret;
404         return ret;
405     }
406 
407     lldb::addr_t MallocPointer ()
408     {
409         return Malloc(m_target_data.getPointerSize(), m_target_data.getPointerPrefAlignment());
410     }
411 
412     lldb::addr_t Malloc (llvm::Type *type)
413     {
414         lldb_private::Error alloc_error;
415 
416         return Malloc(m_target_data.getTypeAllocSize(type), m_target_data.getPrefTypeAlignment(type));
417     }
418 
419     std::string PrintData (lldb::addr_t addr, llvm::Type *type)
420     {
421         size_t length = m_target_data.getTypeStoreSize(type);
422 
423         lldb_private::DataBufferHeap buf(length, 0);
424 
425         lldb_private::Error read_error;
426 
427         m_execution_unit.ReadMemory(buf.GetBytes(), addr, length, read_error);
428 
429         if (!read_error.Success())
430             return std::string("<couldn't read data>");
431 
432         lldb_private::StreamString ss;
433 
434         for (size_t i = 0; i < length; i++)
435         {
436             if ((!(i & 0xf)) && i)
437                 ss.Printf("%02hhx - ", buf.GetBytes()[i]);
438             else
439                 ss.Printf("%02hhx ", buf.GetBytes()[i]);
440         }
441 
442         return ss.GetString();
443     }
444 
445     lldb::addr_t ResolveValue (const Value *value, Module &module)
446     {
447         ValueMap::iterator i = m_values.find(value);
448 
449         if (i != m_values.end())
450             return i->second;
451 
452         // Fall back and allocate space [allocation type Alloca]
453 
454         lldb::addr_t data_address = Malloc(value->getType());
455 
456         if (const Constant *constant = dyn_cast<Constant>(value))
457         {
458             if (!ResolveConstant (data_address, constant))
459             {
460                 lldb_private::Error free_error;
461                 m_execution_unit.Free(data_address, free_error);
462                 return LLDB_INVALID_ADDRESS;
463             }
464         }
465 
466         m_values[value] = data_address;
467         return data_address;
468     }
469 };
470 
471 static const char *unsupported_opcode_error         = "Interpreter doesn't handle one of the expression's opcodes";
472 static const char *unsupported_operand_error        = "Interpreter doesn't handle one of the expression's operands";
473 //static const char *interpreter_initialization_error = "Interpreter couldn't be initialized";
474 static const char *interpreter_internal_error       = "Interpreter encountered an internal error";
475 static const char *bad_value_error                  = "Interpreter couldn't resolve a value during execution";
476 static const char *memory_allocation_error          = "Interpreter couldn't allocate memory";
477 static const char *memory_write_error               = "Interpreter couldn't write to memory";
478 static const char *memory_read_error                = "Interpreter couldn't read from memory";
479 static const char *infinite_loop_error              = "Interpreter ran for too many cycles";
480 //static const char *bad_result_error                 = "Result of expression is in bad memory";
481 
482 static bool
483 CanResolveConstant (llvm::Constant *constant)
484 {
485     switch (constant->getValueID())
486     {
487     default:
488         return false;
489     case Value::ConstantIntVal:
490     case Value::ConstantFPVal:
491     case Value::FunctionVal:
492         return true;
493     case Value::ConstantExprVal:
494         if (const ConstantExpr *constant_expr = dyn_cast<ConstantExpr>(constant))
495         {
496             switch (constant_expr->getOpcode())
497             {
498                 default:
499                     return false;
500                 case Instruction::IntToPtr:
501                 case Instruction::PtrToInt:
502                 case Instruction::BitCast:
503                     return CanResolveConstant(constant_expr->getOperand(0));
504                 case Instruction::GetElementPtr:
505                 {
506                     ConstantExpr::const_op_iterator op_cursor = constant_expr->op_begin();
507                     Constant *base = dyn_cast<Constant>(*op_cursor);
508                     if (!base)
509                         return false;
510 
511                     return CanResolveConstant(base);
512                 }
513             }
514         } else {
515             return false;
516         }
517     case Value::ConstantPointerNullVal:
518         return true;
519     }
520 }
521 
522 bool
523 IRInterpreter::CanInterpret (llvm::Module &module,
524                              llvm::Function &function,
525                              lldb_private::Error &error,
526                              const bool support_function_calls)
527 {
528     lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
529 
530     bool saw_function_with_body = false;
531 
532     for (Module::iterator fi = module.begin(), fe = module.end();
533          fi != fe;
534          ++fi)
535     {
536         if (fi->begin() != fi->end())
537         {
538             if (saw_function_with_body)
539                 return false;
540             saw_function_with_body = true;
541         }
542     }
543 
544     for (Function::iterator bbi = function.begin(), bbe = function.end();
545          bbi != bbe;
546          ++bbi)
547     {
548         for (BasicBlock::iterator ii = bbi->begin(), ie = bbi->end();
549              ii != ie;
550              ++ii)
551         {
552             switch (ii->getOpcode())
553             {
554             default:
555                 {
556                     if (log)
557                         log->Printf("Unsupported instruction: %s", PrintValue(&*ii).c_str());
558                     error.SetErrorToGenericError();
559                     error.SetErrorString(unsupported_opcode_error);
560                     return false;
561                 }
562             case Instruction::Add:
563             case Instruction::Alloca:
564             case Instruction::BitCast:
565             case Instruction::Br:
566                 break;
567             case Instruction::Call:
568                 {
569                     CallInst *call_inst = dyn_cast<CallInst>(ii);
570 
571                     if (!call_inst)
572                     {
573                         error.SetErrorToGenericError();
574                         error.SetErrorString(interpreter_internal_error);
575                         return false;
576                     }
577 
578                     if (!CanIgnoreCall(call_inst) && !support_function_calls)
579                     {
580                         if (log)
581                             log->Printf("Unsupported instruction: %s", PrintValue(&*ii).c_str());
582                         error.SetErrorToGenericError();
583                         error.SetErrorString(unsupported_opcode_error);
584                         return false;
585                     }
586                 }
587                 break;
588             case Instruction::GetElementPtr:
589                 break;
590             case Instruction::ICmp:
591                 {
592                     ICmpInst *icmp_inst = dyn_cast<ICmpInst>(ii);
593 
594                     if (!icmp_inst)
595                     {
596                         error.SetErrorToGenericError();
597                         error.SetErrorString(interpreter_internal_error);
598                         return false;
599                     }
600 
601                     switch (icmp_inst->getPredicate())
602                     {
603                     default:
604                     {
605                         if (log)
606                             log->Printf("Unsupported ICmp predicate: %s", PrintValue(&*ii).c_str());
607 
608                         error.SetErrorToGenericError();
609                         error.SetErrorString(unsupported_opcode_error);
610                         return false;
611                     }
612                     case CmpInst::ICMP_EQ:
613                     case CmpInst::ICMP_NE:
614                     case CmpInst::ICMP_UGT:
615                     case CmpInst::ICMP_UGE:
616                     case CmpInst::ICMP_ULT:
617                     case CmpInst::ICMP_ULE:
618                     case CmpInst::ICMP_SGT:
619                     case CmpInst::ICMP_SGE:
620                     case CmpInst::ICMP_SLT:
621                     case CmpInst::ICMP_SLE:
622                         break;
623                     }
624                 }
625                 break;
626             case Instruction::And:
627             case Instruction::AShr:
628             case Instruction::IntToPtr:
629             case Instruction::PtrToInt:
630             case Instruction::Load:
631             case Instruction::LShr:
632             case Instruction::Mul:
633             case Instruction::Or:
634             case Instruction::Ret:
635             case Instruction::SDiv:
636             case Instruction::SExt:
637             case Instruction::Shl:
638             case Instruction::SRem:
639             case Instruction::Store:
640             case Instruction::Sub:
641             case Instruction::Trunc:
642             case Instruction::UDiv:
643             case Instruction::URem:
644             case Instruction::Xor:
645             case Instruction::ZExt:
646                 break;
647             }
648 
649             for (int oi = 0, oe = ii->getNumOperands();
650                  oi != oe;
651                  ++oi)
652             {
653                 Value *operand = ii->getOperand(oi);
654                 Type *operand_type = operand->getType();
655 
656                 switch (operand_type->getTypeID())
657                 {
658                 default:
659                     break;
660                 case Type::VectorTyID:
661                     {
662                         if (log)
663                             log->Printf("Unsupported operand type: %s", PrintType(operand_type).c_str());
664                         error.SetErrorString(unsupported_operand_error);
665                         return false;
666                     }
667                 }
668 
669                 if (Constant *constant = llvm::dyn_cast<Constant>(operand))
670                 {
671                     if (!CanResolveConstant(constant))
672                     {
673                         if (log)
674                             log->Printf("Unsupported constant: %s", PrintValue(constant).c_str());
675                         error.SetErrorString(unsupported_operand_error);
676                         return false;
677                     }
678                 }
679             }
680         }
681 
682     }
683 
684     return true;}
685 
686 bool
687 IRInterpreter::Interpret (llvm::Module &module,
688                           llvm::Function &function,
689                           llvm::ArrayRef<lldb::addr_t> args,
690                           lldb_private::IRExecutionUnit &execution_unit,
691                           lldb_private::Error &error,
692                           lldb::addr_t stack_frame_bottom,
693                           lldb::addr_t stack_frame_top,
694                           lldb_private::ExecutionContext &exe_ctx)
695 {
696     lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
697 
698     if (log)
699     {
700         std::string s;
701         raw_string_ostream oss(s);
702 
703         module.print(oss, NULL);
704 
705         oss.flush();
706 
707         log->Printf("Module as passed in to IRInterpreter::Interpret: \n\"%s\"", s.c_str());
708     }
709 
710     DataLayout data_layout(&module);
711 
712     InterpreterStackFrame frame(data_layout, execution_unit, stack_frame_bottom, stack_frame_top);
713 
714     if (frame.m_frame_process_address == LLDB_INVALID_ADDRESS)
715     {
716         error.SetErrorString("Couldn't allocate stack frame");
717     }
718 
719     int arg_index = 0;
720 
721     for (llvm::Function::arg_iterator ai = function.arg_begin(), ae = function.arg_end();
722          ai != ae;
723          ++ai, ++arg_index)
724     {
725         if (args.size() <= static_cast<size_t>(arg_index))
726         {
727             error.SetErrorString ("Not enough arguments passed in to function");
728             return false;
729         }
730 
731         lldb::addr_t ptr = args[arg_index];
732 
733         frame.MakeArgument(&*ai, ptr);
734     }
735 
736     uint32_t num_insts = 0;
737 
738     frame.Jump(&function.front());
739 
740     while (frame.m_ii != frame.m_ie && (++num_insts < 4096))
741     {
742         const Instruction *inst = &*frame.m_ii;
743 
744         if (log)
745             log->Printf("Interpreting %s", PrintValue(inst).c_str());
746 
747         switch (inst->getOpcode())
748         {
749             default:
750                 break;
751 
752             case Instruction::Add:
753             case Instruction::Sub:
754             case Instruction::Mul:
755             case Instruction::SDiv:
756             case Instruction::UDiv:
757             case Instruction::SRem:
758             case Instruction::URem:
759             case Instruction::Shl:
760             case Instruction::LShr:
761             case Instruction::AShr:
762             case Instruction::And:
763             case Instruction::Or:
764             case Instruction::Xor:
765             {
766                 const BinaryOperator *bin_op = dyn_cast<BinaryOperator>(inst);
767 
768                 if (!bin_op)
769                 {
770                     if (log)
771                         log->Printf("getOpcode() returns %s, but instruction is not a BinaryOperator", inst->getOpcodeName());
772                     error.SetErrorToGenericError();
773                     error.SetErrorString(interpreter_internal_error);
774                     return false;
775                 }
776 
777                 Value *lhs = inst->getOperand(0);
778                 Value *rhs = inst->getOperand(1);
779 
780                 lldb_private::Scalar L;
781                 lldb_private::Scalar R;
782 
783                 if (!frame.EvaluateValue(L, lhs, module))
784                 {
785                     if (log)
786                         log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
787                     error.SetErrorToGenericError();
788                     error.SetErrorString(bad_value_error);
789                     return false;
790                 }
791 
792                 if (!frame.EvaluateValue(R, rhs, module))
793                 {
794                     if (log)
795                         log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
796                     error.SetErrorToGenericError();
797                     error.SetErrorString(bad_value_error);
798                     return false;
799                 }
800 
801                 lldb_private::Scalar result;
802 
803                 switch (inst->getOpcode())
804                 {
805                     default:
806                         break;
807                     case Instruction::Add:
808                         result = L + R;
809                         break;
810                     case Instruction::Mul:
811                         result = L * R;
812                         break;
813                     case Instruction::Sub:
814                         result = L - R;
815                         break;
816                     case Instruction::SDiv:
817                         L.MakeSigned();
818                         R.MakeSigned();
819                         result = L / R;
820                         break;
821                     case Instruction::UDiv:
822                         result = L.GetRawBits64(0) / R.GetRawBits64(1);
823                         break;
824                     case Instruction::SRem:
825                         L.MakeSigned();
826                         R.MakeSigned();
827                         result = L % R;
828                         break;
829                     case Instruction::URem:
830                         result = L.GetRawBits64(0) % R.GetRawBits64(1);
831                         break;
832                     case Instruction::Shl:
833                         result = L << R;
834                         break;
835                     case Instruction::AShr:
836                         result = L >> R;
837                         break;
838                     case Instruction::LShr:
839                         result = L;
840                         result.ShiftRightLogical(R);
841                         break;
842                     case Instruction::And:
843                         result = L & R;
844                         break;
845                     case Instruction::Or:
846                         result = L | R;
847                         break;
848                     case Instruction::Xor:
849                         result = L ^ R;
850                         break;
851                 }
852 
853                 frame.AssignValue(inst, result, module);
854 
855                 if (log)
856                 {
857                     log->Printf("Interpreted a %s", inst->getOpcodeName());
858                     log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
859                     log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
860                     log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
861                 }
862             }
863                 break;
864             case Instruction::Alloca:
865             {
866                 const AllocaInst *alloca_inst = dyn_cast<AllocaInst>(inst);
867 
868                 if (!alloca_inst)
869                 {
870                     if (log)
871                         log->Printf("getOpcode() returns Alloca, but instruction is not an AllocaInst");
872                     error.SetErrorToGenericError();
873                     error.SetErrorString(interpreter_internal_error);
874                     return false;
875                 }
876 
877                 if (alloca_inst->isArrayAllocation())
878                 {
879                     if (log)
880                         log->Printf("AllocaInsts are not handled if isArrayAllocation() is true");
881                     error.SetErrorToGenericError();
882                     error.SetErrorString(unsupported_opcode_error);
883                     return false;
884                 }
885 
886                 // The semantics of Alloca are:
887                 //   Create a region R of virtual memory of type T, backed by a data buffer
888                 //   Create a region P of virtual memory of type T*, backed by a data buffer
889                 //   Write the virtual address of R into P
890 
891                 Type *T = alloca_inst->getAllocatedType();
892                 Type *Tptr = alloca_inst->getType();
893 
894                 lldb::addr_t R = frame.Malloc(T);
895 
896                 if (R == LLDB_INVALID_ADDRESS)
897                 {
898                     if (log)
899                         log->Printf("Couldn't allocate memory for an AllocaInst");
900                     error.SetErrorToGenericError();
901                     error.SetErrorString(memory_allocation_error);
902                     return false;
903                 }
904 
905                 lldb::addr_t P = frame.Malloc(Tptr);
906 
907                 if (P == LLDB_INVALID_ADDRESS)
908                 {
909                     if (log)
910                         log->Printf("Couldn't allocate the result pointer for an AllocaInst");
911                     error.SetErrorToGenericError();
912                     error.SetErrorString(memory_allocation_error);
913                     return false;
914                 }
915 
916                 lldb_private::Error write_error;
917 
918                 execution_unit.WritePointerToMemory(P, R, write_error);
919 
920                 if (!write_error.Success())
921                 {
922                     if (log)
923                         log->Printf("Couldn't write the result pointer for an AllocaInst");
924                     error.SetErrorToGenericError();
925                     error.SetErrorString(memory_write_error);
926                     lldb_private::Error free_error;
927                     execution_unit.Free(P, free_error);
928                     execution_unit.Free(R, free_error);
929                     return false;
930                 }
931 
932                 frame.m_values[alloca_inst] = P;
933 
934                 if (log)
935                 {
936                     log->Printf("Interpreted an AllocaInst");
937                     log->Printf("  R : 0x%" PRIx64, R);
938                     log->Printf("  P : 0x%" PRIx64, P);
939                 }
940             }
941                 break;
942             case Instruction::BitCast:
943             case Instruction::ZExt:
944             {
945                 const CastInst *cast_inst = dyn_cast<CastInst>(inst);
946 
947                 if (!cast_inst)
948                 {
949                     if (log)
950                         log->Printf("getOpcode() returns %s, but instruction is not a BitCastInst", cast_inst->getOpcodeName());
951                     error.SetErrorToGenericError();
952                     error.SetErrorString(interpreter_internal_error);
953                     return false;
954                 }
955 
956                 Value *source = cast_inst->getOperand(0);
957 
958                 lldb_private::Scalar S;
959 
960                 if (!frame.EvaluateValue(S, source, module))
961                 {
962                     if (log)
963                         log->Printf("Couldn't evaluate %s", PrintValue(source).c_str());
964                     error.SetErrorToGenericError();
965                     error.SetErrorString(bad_value_error);
966                     return false;
967                 }
968 
969                 frame.AssignValue(inst, S, module);
970             }
971                 break;
972             case Instruction::SExt:
973             {
974                 const CastInst *cast_inst = dyn_cast<CastInst>(inst);
975 
976                 if (!cast_inst)
977                 {
978                     if (log)
979                         log->Printf("getOpcode() returns %s, but instruction is not a BitCastInst", cast_inst->getOpcodeName());
980                     error.SetErrorToGenericError();
981                     error.SetErrorString(interpreter_internal_error);
982                     return false;
983                 }
984 
985                 Value *source = cast_inst->getOperand(0);
986 
987                 lldb_private::Scalar S;
988 
989                 if (!frame.EvaluateValue(S, source, module))
990                 {
991                     if (log)
992                         log->Printf("Couldn't evaluate %s", PrintValue(source).c_str());
993                     error.SetErrorToGenericError();
994                     error.SetErrorString(bad_value_error);
995                     return false;
996                 }
997 
998                 S.MakeSigned();
999 
1000                 lldb_private::Scalar S_signextend(S.SLongLong());
1001 
1002                 frame.AssignValue(inst, S_signextend, module);
1003             }
1004                 break;
1005             case Instruction::Br:
1006             {
1007                 const BranchInst *br_inst = dyn_cast<BranchInst>(inst);
1008 
1009                 if (!br_inst)
1010                 {
1011                     if (log)
1012                         log->Printf("getOpcode() returns Br, but instruction is not a BranchInst");
1013                     error.SetErrorToGenericError();
1014                     error.SetErrorString(interpreter_internal_error);
1015                     return false;
1016                 }
1017 
1018                 if (br_inst->isConditional())
1019                 {
1020                     Value *condition = br_inst->getCondition();
1021 
1022                     lldb_private::Scalar C;
1023 
1024                     if (!frame.EvaluateValue(C, condition, module))
1025                     {
1026                         if (log)
1027                             log->Printf("Couldn't evaluate %s", PrintValue(condition).c_str());
1028                         error.SetErrorToGenericError();
1029                         error.SetErrorString(bad_value_error);
1030                         return false;
1031                     }
1032 
1033                     if (C.GetRawBits64(0))
1034                         frame.Jump(br_inst->getSuccessor(0));
1035                     else
1036                         frame.Jump(br_inst->getSuccessor(1));
1037 
1038                     if (log)
1039                     {
1040                         log->Printf("Interpreted a BrInst with a condition");
1041                         log->Printf("  cond : %s", frame.SummarizeValue(condition).c_str());
1042                     }
1043                 }
1044                 else
1045                 {
1046                     frame.Jump(br_inst->getSuccessor(0));
1047 
1048                     if (log)
1049                     {
1050                         log->Printf("Interpreted a BrInst with no condition");
1051                     }
1052                 }
1053             }
1054                 continue;
1055             case Instruction::GetElementPtr:
1056             {
1057                 const GetElementPtrInst *gep_inst = dyn_cast<GetElementPtrInst>(inst);
1058 
1059                 if (!gep_inst)
1060                 {
1061                     if (log)
1062                         log->Printf("getOpcode() returns GetElementPtr, but instruction is not a GetElementPtrInst");
1063                     error.SetErrorToGenericError();
1064                     error.SetErrorString(interpreter_internal_error);
1065                     return false;
1066                 }
1067 
1068                 const Value *pointer_operand = gep_inst->getPointerOperand();
1069                 Type *src_elem_ty = gep_inst->getSourceElementType();
1070 
1071                 lldb_private::Scalar P;
1072 
1073                 if (!frame.EvaluateValue(P, pointer_operand, module))
1074                 {
1075                     if (log)
1076                         log->Printf("Couldn't evaluate %s", PrintValue(pointer_operand).c_str());
1077                     error.SetErrorToGenericError();
1078                     error.SetErrorString(bad_value_error);
1079                     return false;
1080                 }
1081 
1082                 typedef SmallVector <Value *, 8> IndexVector;
1083                 typedef IndexVector::iterator IndexIterator;
1084 
1085                 SmallVector <Value *, 8> indices (gep_inst->idx_begin(),
1086                                                   gep_inst->idx_end());
1087 
1088                 SmallVector <Value *, 8> const_indices;
1089 
1090                 for (IndexIterator ii = indices.begin(), ie = indices.end();
1091                      ii != ie;
1092                      ++ii)
1093                 {
1094                     ConstantInt *constant_index = dyn_cast<ConstantInt>(*ii);
1095 
1096                     if (!constant_index)
1097                     {
1098                         lldb_private::Scalar I;
1099 
1100                         if (!frame.EvaluateValue(I, *ii, module))
1101                         {
1102                             if (log)
1103                                 log->Printf("Couldn't evaluate %s", PrintValue(*ii).c_str());
1104                             error.SetErrorToGenericError();
1105                             error.SetErrorString(bad_value_error);
1106                             return false;
1107                         }
1108 
1109                         if (log)
1110                             log->Printf("Evaluated constant index %s as %llu", PrintValue(*ii).c_str(), I.ULongLong(LLDB_INVALID_ADDRESS));
1111 
1112                         constant_index = cast<ConstantInt>(ConstantInt::get((*ii)->getType(), I.ULongLong(LLDB_INVALID_ADDRESS)));
1113                     }
1114 
1115                     const_indices.push_back(constant_index);
1116                 }
1117 
1118                 uint64_t offset = data_layout.getIndexedOffsetInType(src_elem_ty, const_indices);
1119 
1120                 lldb_private::Scalar Poffset = P + offset;
1121 
1122                 frame.AssignValue(inst, Poffset, module);
1123 
1124                 if (log)
1125                 {
1126                     log->Printf("Interpreted a GetElementPtrInst");
1127                     log->Printf("  P       : %s", frame.SummarizeValue(pointer_operand).c_str());
1128                     log->Printf("  Poffset : %s", frame.SummarizeValue(inst).c_str());
1129                 }
1130             }
1131                 break;
1132             case Instruction::ICmp:
1133             {
1134                 const ICmpInst *icmp_inst = dyn_cast<ICmpInst>(inst);
1135 
1136                 if (!icmp_inst)
1137                 {
1138                     if (log)
1139                         log->Printf("getOpcode() returns ICmp, but instruction is not an ICmpInst");
1140                     error.SetErrorToGenericError();
1141                     error.SetErrorString(interpreter_internal_error);
1142                     return false;
1143                 }
1144 
1145                 CmpInst::Predicate predicate = icmp_inst->getPredicate();
1146 
1147                 Value *lhs = inst->getOperand(0);
1148                 Value *rhs = inst->getOperand(1);
1149 
1150                 lldb_private::Scalar L;
1151                 lldb_private::Scalar R;
1152 
1153                 if (!frame.EvaluateValue(L, lhs, module))
1154                 {
1155                     if (log)
1156                         log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
1157                     error.SetErrorToGenericError();
1158                     error.SetErrorString(bad_value_error);
1159                     return false;
1160                 }
1161 
1162                 if (!frame.EvaluateValue(R, rhs, module))
1163                 {
1164                     if (log)
1165                         log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
1166                     error.SetErrorToGenericError();
1167                     error.SetErrorString(bad_value_error);
1168                     return false;
1169                 }
1170 
1171                 lldb_private::Scalar result;
1172 
1173                 switch (predicate)
1174                 {
1175                     default:
1176                         return false;
1177                     case CmpInst::ICMP_EQ:
1178                         result = (L == R);
1179                         break;
1180                     case CmpInst::ICMP_NE:
1181                         result = (L != R);
1182                         break;
1183                     case CmpInst::ICMP_UGT:
1184                         result = (L.GetRawBits64(0) > R.GetRawBits64(0));
1185                         break;
1186                     case CmpInst::ICMP_UGE:
1187                         result = (L.GetRawBits64(0) >= R.GetRawBits64(0));
1188                         break;
1189                     case CmpInst::ICMP_ULT:
1190                         result = (L.GetRawBits64(0) < R.GetRawBits64(0));
1191                         break;
1192                     case CmpInst::ICMP_ULE:
1193                         result = (L.GetRawBits64(0) <= R.GetRawBits64(0));
1194                         break;
1195                     case CmpInst::ICMP_SGT:
1196                         L.MakeSigned();
1197                         R.MakeSigned();
1198                         result = (L > R);
1199                         break;
1200                     case CmpInst::ICMP_SGE:
1201                         L.MakeSigned();
1202                         R.MakeSigned();
1203                         result = (L >= R);
1204                         break;
1205                     case CmpInst::ICMP_SLT:
1206                         L.MakeSigned();
1207                         R.MakeSigned();
1208                         result = (L < R);
1209                         break;
1210                     case CmpInst::ICMP_SLE:
1211                         L.MakeSigned();
1212                         R.MakeSigned();
1213                         result = (L <= R);
1214                         break;
1215                 }
1216 
1217                 frame.AssignValue(inst, result, module);
1218 
1219                 if (log)
1220                 {
1221                     log->Printf("Interpreted an ICmpInst");
1222                     log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
1223                     log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
1224                     log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
1225                 }
1226             }
1227                 break;
1228             case Instruction::IntToPtr:
1229             {
1230                 const IntToPtrInst *int_to_ptr_inst = dyn_cast<IntToPtrInst>(inst);
1231 
1232                 if (!int_to_ptr_inst)
1233                 {
1234                     if (log)
1235                         log->Printf("getOpcode() returns IntToPtr, but instruction is not an IntToPtrInst");
1236                     error.SetErrorToGenericError();
1237                     error.SetErrorString(interpreter_internal_error);
1238                     return false;
1239                 }
1240 
1241                 Value *src_operand = int_to_ptr_inst->getOperand(0);
1242 
1243                 lldb_private::Scalar I;
1244 
1245                 if (!frame.EvaluateValue(I, src_operand, module))
1246                 {
1247                     if (log)
1248                         log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
1249                     error.SetErrorToGenericError();
1250                     error.SetErrorString(bad_value_error);
1251                     return false;
1252                 }
1253 
1254                 frame.AssignValue(inst, I, module);
1255 
1256                 if (log)
1257                 {
1258                     log->Printf("Interpreted an IntToPtr");
1259                     log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1260                     log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1261                 }
1262             }
1263                 break;
1264             case Instruction::PtrToInt:
1265             {
1266                 const PtrToIntInst *ptr_to_int_inst = dyn_cast<PtrToIntInst>(inst);
1267 
1268                 if (!ptr_to_int_inst)
1269                 {
1270                     if (log)
1271                         log->Printf("getOpcode() returns PtrToInt, but instruction is not an PtrToIntInst");
1272                     error.SetErrorToGenericError();
1273                     error.SetErrorString(interpreter_internal_error);
1274                     return false;
1275                 }
1276 
1277                 Value *src_operand = ptr_to_int_inst->getOperand(0);
1278 
1279                 lldb_private::Scalar I;
1280 
1281                 if (!frame.EvaluateValue(I, src_operand, module))
1282                 {
1283                     if (log)
1284                         log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
1285                     error.SetErrorToGenericError();
1286                     error.SetErrorString(bad_value_error);
1287                     return false;
1288                 }
1289 
1290                 frame.AssignValue(inst, I, module);
1291 
1292                 if (log)
1293                 {
1294                     log->Printf("Interpreted a PtrToInt");
1295                     log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1296                     log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1297                 }
1298             }
1299                 break;
1300             case Instruction::Trunc:
1301             {
1302                 const TruncInst *trunc_inst = dyn_cast<TruncInst>(inst);
1303 
1304                 if (!trunc_inst)
1305                 {
1306                     if (log)
1307                         log->Printf("getOpcode() returns Trunc, but instruction is not a TruncInst");
1308                     error.SetErrorToGenericError();
1309                     error.SetErrorString(interpreter_internal_error);
1310                     return false;
1311                 }
1312 
1313                 Value *src_operand = trunc_inst->getOperand(0);
1314 
1315                 lldb_private::Scalar I;
1316 
1317                 if (!frame.EvaluateValue(I, src_operand, module))
1318                 {
1319                     if (log)
1320                         log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
1321                     error.SetErrorToGenericError();
1322                     error.SetErrorString(bad_value_error);
1323                     return false;
1324                 }
1325 
1326                 frame.AssignValue(inst, I, module);
1327 
1328                 if (log)
1329                 {
1330                     log->Printf("Interpreted a Trunc");
1331                     log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1332                     log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1333                 }
1334             }
1335                 break;
1336             case Instruction::Load:
1337             {
1338                 const LoadInst *load_inst = dyn_cast<LoadInst>(inst);
1339 
1340                 if (!load_inst)
1341                 {
1342                     if (log)
1343                         log->Printf("getOpcode() returns Load, but instruction is not a LoadInst");
1344                     error.SetErrorToGenericError();
1345                     error.SetErrorString(interpreter_internal_error);
1346                     return false;
1347                 }
1348 
1349                 // The semantics of Load are:
1350                 //   Create a region D that will contain the loaded data
1351                 //   Resolve the region P containing a pointer
1352                 //   Dereference P to get the region R that the data should be loaded from
1353                 //   Transfer a unit of type type(D) from R to D
1354 
1355                 const Value *pointer_operand = load_inst->getPointerOperand();
1356 
1357                 Type *pointer_ty = pointer_operand->getType();
1358                 PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1359                 if (!pointer_ptr_ty)
1360                 {
1361                     if (log)
1362                         log->Printf("getPointerOperand()->getType() is not a PointerType");
1363                     error.SetErrorToGenericError();
1364                     error.SetErrorString(interpreter_internal_error);
1365                     return false;
1366                 }
1367                 Type *target_ty = pointer_ptr_ty->getElementType();
1368 
1369                 lldb::addr_t D = frame.ResolveValue(load_inst, module);
1370                 lldb::addr_t P = frame.ResolveValue(pointer_operand, module);
1371 
1372                 if (D == LLDB_INVALID_ADDRESS)
1373                 {
1374                     if (log)
1375                         log->Printf("LoadInst's value doesn't resolve to anything");
1376                     error.SetErrorToGenericError();
1377                     error.SetErrorString(bad_value_error);
1378                     return false;
1379                 }
1380 
1381                 if (P == LLDB_INVALID_ADDRESS)
1382                 {
1383                     if (log)
1384                         log->Printf("LoadInst's pointer doesn't resolve to anything");
1385                     error.SetErrorToGenericError();
1386                     error.SetErrorString(bad_value_error);
1387                     return false;
1388                 }
1389 
1390                 lldb::addr_t R;
1391                 lldb_private::Error read_error;
1392                 execution_unit.ReadPointerFromMemory(&R, P, read_error);
1393 
1394                 if (!read_error.Success())
1395                 {
1396                     if (log)
1397                         log->Printf("Couldn't read the address to be loaded for a LoadInst");
1398                     error.SetErrorToGenericError();
1399                     error.SetErrorString(memory_read_error);
1400                     return false;
1401                 }
1402 
1403                 size_t target_size = data_layout.getTypeStoreSize(target_ty);
1404                 lldb_private::DataBufferHeap buffer(target_size, 0);
1405 
1406                 read_error.Clear();
1407                 execution_unit.ReadMemory(buffer.GetBytes(), R, buffer.GetByteSize(), read_error);
1408                 if (!read_error.Success())
1409                 {
1410                     if (log)
1411                         log->Printf("Couldn't read from a region on behalf of a LoadInst");
1412                     error.SetErrorToGenericError();
1413                     error.SetErrorString(memory_read_error);
1414                     return false;
1415                 }
1416 
1417                 lldb_private::Error write_error;
1418                 execution_unit.WriteMemory(D, buffer.GetBytes(), buffer.GetByteSize(), write_error);
1419                 if (!write_error.Success())
1420                 {
1421                     if (log)
1422                         log->Printf("Couldn't write to a region on behalf of a LoadInst");
1423                     error.SetErrorToGenericError();
1424                     error.SetErrorString(memory_read_error);
1425                     return false;
1426                 }
1427 
1428                 if (log)
1429                 {
1430                     log->Printf("Interpreted a LoadInst");
1431                     log->Printf("  P : 0x%" PRIx64, P);
1432                     log->Printf("  R : 0x%" PRIx64, R);
1433                     log->Printf("  D : 0x%" PRIx64, D);
1434                 }
1435             }
1436                 break;
1437             case Instruction::Ret:
1438             {
1439                 return true;
1440             }
1441             case Instruction::Store:
1442             {
1443                 const StoreInst *store_inst = dyn_cast<StoreInst>(inst);
1444 
1445                 if (!store_inst)
1446                 {
1447                     if (log)
1448                         log->Printf("getOpcode() returns Store, but instruction is not a StoreInst");
1449                     error.SetErrorToGenericError();
1450                     error.SetErrorString(interpreter_internal_error);
1451                     return false;
1452                 }
1453 
1454                 // The semantics of Store are:
1455                 //   Resolve the region D containing the data to be stored
1456                 //   Resolve the region P containing a pointer
1457                 //   Dereference P to get the region R that the data should be stored in
1458                 //   Transfer a unit of type type(D) from D to R
1459 
1460                 const Value *value_operand = store_inst->getValueOperand();
1461                 const Value *pointer_operand = store_inst->getPointerOperand();
1462 
1463                 Type *pointer_ty = pointer_operand->getType();
1464                 PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1465                 if (!pointer_ptr_ty)
1466                     return false;
1467                 Type *target_ty = pointer_ptr_ty->getElementType();
1468 
1469                 lldb::addr_t D = frame.ResolveValue(value_operand, module);
1470                 lldb::addr_t P = frame.ResolveValue(pointer_operand, module);
1471 
1472                 if (D == LLDB_INVALID_ADDRESS)
1473                 {
1474                     if (log)
1475                         log->Printf("StoreInst's value doesn't resolve to anything");
1476                     error.SetErrorToGenericError();
1477                     error.SetErrorString(bad_value_error);
1478                     return false;
1479                 }
1480 
1481                 if (P == LLDB_INVALID_ADDRESS)
1482                 {
1483                     if (log)
1484                         log->Printf("StoreInst's pointer doesn't resolve to anything");
1485                     error.SetErrorToGenericError();
1486                     error.SetErrorString(bad_value_error);
1487                     return false;
1488                 }
1489 
1490                 lldb::addr_t R;
1491                 lldb_private::Error read_error;
1492                 execution_unit.ReadPointerFromMemory(&R, P, read_error);
1493 
1494                 if (!read_error.Success())
1495                 {
1496                     if (log)
1497                         log->Printf("Couldn't read the address to be loaded for a LoadInst");
1498                     error.SetErrorToGenericError();
1499                     error.SetErrorString(memory_read_error);
1500                     return false;
1501                 }
1502 
1503                 size_t target_size = data_layout.getTypeStoreSize(target_ty);
1504                 lldb_private::DataBufferHeap buffer(target_size, 0);
1505 
1506                 read_error.Clear();
1507                 execution_unit.ReadMemory(buffer.GetBytes(), D, buffer.GetByteSize(), read_error);
1508                 if (!read_error.Success())
1509                 {
1510                     if (log)
1511                         log->Printf("Couldn't read from a region on behalf of a StoreInst");
1512                     error.SetErrorToGenericError();
1513                     error.SetErrorString(memory_read_error);
1514                     return false;
1515                 }
1516 
1517                 lldb_private::Error write_error;
1518                 execution_unit.WriteMemory(R, buffer.GetBytes(), buffer.GetByteSize(), write_error);
1519                 if (!write_error.Success())
1520                 {
1521                     if (log)
1522                         log->Printf("Couldn't write to a region on behalf of a StoreInst");
1523                     error.SetErrorToGenericError();
1524                     error.SetErrorString(memory_write_error);
1525                     return false;
1526                 }
1527 
1528                 if (log)
1529                 {
1530                     log->Printf("Interpreted a StoreInst");
1531                     log->Printf("  D : 0x%" PRIx64, D);
1532                     log->Printf("  P : 0x%" PRIx64, P);
1533                     log->Printf("  R : 0x%" PRIx64, R);
1534                 }
1535             }
1536                 break;
1537             case Instruction::Call:
1538             {
1539                 const CallInst *call_inst = dyn_cast<CallInst>(inst);
1540 
1541                 if (!call_inst)
1542                 {
1543                     if (log)
1544                        log->Printf("getOpcode() returns %s, but instruction is not a CallInst", inst->getOpcodeName());
1545                     error.SetErrorToGenericError();
1546                     error.SetErrorString(interpreter_internal_error);
1547                     return false;
1548                 }
1549 
1550                 if (CanIgnoreCall(call_inst))
1551                     break;
1552 
1553                 // Get the return type
1554                 llvm::Type *returnType = call_inst->getType();
1555                 if (returnType == nullptr)
1556                 {
1557                     error.SetErrorToGenericError();
1558                     error.SetErrorString("unable to access return type");
1559                     return false;
1560                 }
1561 
1562                 // Work with void, integer and pointer return types
1563                 if (!returnType->isVoidTy() &&
1564                     !returnType->isIntegerTy() &&
1565                     !returnType->isPointerTy())
1566                 {
1567                     error.SetErrorToGenericError();
1568                     error.SetErrorString("return type is not supported");
1569                     return false;
1570                 }
1571 
1572                 // Check we can actually get a thread
1573                 if (exe_ctx.GetThreadPtr() == nullptr)
1574                 {
1575                     error.SetErrorToGenericError();
1576                     error.SetErrorStringWithFormat("unable to acquire thread");
1577                     return false;
1578                 }
1579 
1580                 // Make sure we have a valid process
1581                 if (!exe_ctx.GetProcessPtr())
1582                 {
1583                     error.SetErrorToGenericError();
1584                     error.SetErrorStringWithFormat("unable to get the process");
1585                     return false;
1586                 }
1587 
1588                 // Find the address of the callee function
1589                 lldb_private::Scalar I;
1590                 const llvm::Value *val = call_inst->getCalledValue();
1591 
1592                 if (!frame.EvaluateValue(I, val, module))
1593                 {
1594                     error.SetErrorToGenericError();
1595                     error.SetErrorString("unable to get address of function");
1596                     return false;
1597                 }
1598                 lldb_private::Address funcAddr(I.ULongLong(LLDB_INVALID_ADDRESS));
1599 
1600                 lldb_private::DiagnosticManager diagnostics;
1601                 lldb_private::EvaluateExpressionOptions options;
1602 
1603                 // We generally receive a function pointer which we must dereference
1604                 llvm::Type* prototype = val->getType();
1605                 if (!prototype->isPointerTy())
1606                 {
1607                     error.SetErrorToGenericError();
1608                     error.SetErrorString("call need function pointer");
1609                     return false;
1610                 }
1611 
1612                 // Dereference the function pointer
1613                 prototype = prototype->getPointerElementType();
1614                 if (!(prototype->isFunctionTy() || prototype->isFunctionVarArg()))
1615                 {
1616                     error.SetErrorToGenericError();
1617                     error.SetErrorString("call need function pointer");
1618                     return false;
1619                 }
1620 
1621                 // Find number of arguments
1622                 const int numArgs = call_inst->getNumArgOperands();
1623 
1624                 // We work with a fixed array of 16 arguments which is our upper limit
1625                 static lldb_private::ABI::CallArgument rawArgs[16];
1626                 if (numArgs >= 16)
1627                 {
1628                     error.SetErrorToGenericError();
1629                     error.SetErrorStringWithFormat("function takes too many arguments");
1630                     return false;
1631                 }
1632 
1633                 // Push all function arguments to the argument list that will
1634                 // be passed to the call function thread plan
1635                 for (int i = 0; i < numArgs; i++)
1636                 {
1637                     // Get details of this argument
1638                     llvm::Value *arg_op = call_inst->getArgOperand(i);
1639                     llvm::Type  *arg_ty = arg_op->getType();
1640 
1641                     // Ensure that this argument is an supported type
1642                     if (!arg_ty->isIntegerTy() && !arg_ty->isPointerTy())
1643                     {
1644                          error.SetErrorToGenericError();
1645                          error.SetErrorStringWithFormat("argument %d must be integer type", i);
1646                          return false;
1647                     }
1648 
1649                     // Extract the arguments value
1650                     lldb_private::Scalar tmp_op = 0;
1651                     if (!frame.EvaluateValue(tmp_op, arg_op, module))
1652                     {
1653                          error.SetErrorToGenericError();
1654                          error.SetErrorStringWithFormat("unable to evaluate argument %d", i);
1655                          return false;
1656                     }
1657 
1658                     // Check if this is a string literal or constant string pointer
1659                     if (arg_ty->isPointerTy())
1660                     {
1661                         // Pointer to just one type
1662                         assert(arg_ty->getNumContainedTypes() == 1);
1663 
1664                         lldb::addr_t addr = tmp_op.ULongLong();
1665                         size_t dataSize = 0;
1666 
1667                         if (execution_unit.GetAllocSize(addr, dataSize))
1668                         {
1669                             // Create the required buffer
1670                             rawArgs[i].size = dataSize;
1671                             rawArgs[i].data_ap.reset(new uint8_t[dataSize + 1]);
1672 
1673                             // Read string from host memory
1674                             execution_unit.ReadMemory(rawArgs[i].data_ap.get(), addr, dataSize, error);
1675                             if (error.Fail())
1676                             {
1677                                 assert(!"we have failed to read the string from memory");
1678                                 return false;
1679                             }
1680                             // Add null terminator
1681                             rawArgs[i].data_ap[dataSize] = '\0';
1682                             rawArgs[i].type = lldb_private::ABI::CallArgument::HostPointer;
1683                         }
1684                         else
1685                         {
1686                             assert(!"unable to locate host data for transfer to device");
1687                             return false;
1688                         }
1689                     }
1690                     else /* if ( arg_ty->isPointerTy() ) */
1691                     {
1692                         rawArgs[i].type = lldb_private::ABI::CallArgument::TargetValue;
1693                         // Get argument size in bytes
1694                         rawArgs[i].size = arg_ty->getIntegerBitWidth() / 8;
1695                         // Push value into argument list for thread plan
1696                         rawArgs[i].value = tmp_op.ULongLong();
1697                     }
1698 
1699                 }
1700 
1701                 // Pack the arguments into an llvm::array
1702                 llvm::ArrayRef<lldb_private::ABI::CallArgument> args(rawArgs, numArgs);
1703 
1704                 // Setup a thread plan to call the target function
1705                 lldb::ThreadPlanSP call_plan_sp(new lldb_private::ThreadPlanCallFunctionUsingABI(
1706                     exe_ctx.GetThreadRef(), funcAddr, *prototype, *returnType, args, options));
1707 
1708                 // Check if the plan is valid
1709                 lldb_private::StreamString ss;
1710                 if (!call_plan_sp || !call_plan_sp->ValidatePlan(&ss))
1711                 {
1712                     error.SetErrorToGenericError();
1713                     error.SetErrorStringWithFormat("unable to make ThreadPlanCallFunctionUsingABI for 0x%llx",
1714                                                    I.ULongLong());
1715                     return false;
1716                 }
1717 
1718                 exe_ctx.GetProcessPtr()->SetRunningUserExpression(true);
1719 
1720                 // Execute the actual function call thread plan
1721                 lldb::ExpressionResults res =
1722                     exe_ctx.GetProcessRef().RunThreadPlan(exe_ctx, call_plan_sp, options, diagnostics);
1723 
1724                 // Check that the thread plan completed successfully
1725                 if (res != lldb::ExpressionResults::eExpressionCompleted)
1726                 {
1727                     error.SetErrorToGenericError();
1728                     error.SetErrorStringWithFormat("ThreadPlanCallFunctionUsingABI failed");
1729                     return false;
1730                 }
1731 
1732                 exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
1733 
1734                 // Void return type
1735                 if (returnType->isVoidTy())
1736                 {
1737                     // Cant assign to void types, so we leave the frame untouched
1738                 }
1739                 else
1740                     // Integer or pointer return type
1741                     if (returnType->isIntegerTy() || returnType->isPointerTy())
1742                     {
1743                         // Get the encapsulated return value
1744                         lldb::ValueObjectSP retVal = call_plan_sp.get()->GetReturnValueObject();
1745 
1746                         lldb_private::Scalar returnVal = -1;
1747                         lldb_private::ValueObject *vobj = retVal.get();
1748 
1749                         // Check if the return value is valid
1750                         if (vobj == nullptr || retVal.empty())
1751                         {
1752                             error.SetErrorToGenericError();
1753                             error.SetErrorStringWithFormat("unable to get the return value");
1754                             return false;
1755                         }
1756 
1757                         // Extract the return value as a integer
1758                         lldb_private::Value & value = vobj->GetValue();
1759                         returnVal = value.GetScalar();
1760 
1761                         // Push the return value as the result
1762                         frame.AssignValue(inst, returnVal, module);
1763                     }
1764             }
1765                 break;
1766         }
1767 
1768         ++frame.m_ii;
1769     }
1770 
1771     if (num_insts >= 4096)
1772     {
1773         error.SetErrorToGenericError();
1774         error.SetErrorString(infinite_loop_error);
1775         return false;
1776     }
1777 
1778     return false;
1779 }
1780