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/Module.h"
12 #include "lldb/Core/ModuleSpec.h"
13 #include "lldb/Core/ValueObject.h"
14 #include "lldb/Expression/DiagnosticManager.h"
15 #include "lldb/Expression/IRExecutionUnit.h"
16 #include "lldb/Expression/IRMemoryMap.h"
17 #include "lldb/Utility/ConstString.h"
18 #include "lldb/Utility/DataExtractor.h"
19 #include "lldb/Utility/Endian.h"
20 #include "lldb/Utility/Log.h"
21 #include "lldb/Utility/Scalar.h"
22 #include "lldb/Utility/Status.h"
23 #include "lldb/Utility/StreamString.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 PrintValue(const Value *value, bool truncate = false) {
47   std::string s;
48   raw_string_ostream rso(s);
49   value->print(rso);
50   rso.flush();
51   if (truncate)
52     s.resize(s.length() - 1);
53 
54   size_t offset;
55   while ((offset = s.find('\n')) != s.npos)
56     s.erase(offset, 1);
57   while (s[0] == ' ' || s[0] == '\t')
58     s.erase(0, 1);
59 
60   return s;
61 }
62 
63 static std::string PrintType(const Type *type, bool truncate = false) {
64   std::string s;
65   raw_string_ostream rso(s);
66   type->print(rso);
67   rso.flush();
68   if (truncate)
69     s.resize(s.length() - 1);
70   return s;
71 }
72 
73 static bool CanIgnoreCall(const CallInst *call) {
74   const llvm::Function *called_function = call->getCalledFunction();
75 
76   if (!called_function)
77     return false;
78 
79   if (called_function->isIntrinsic()) {
80     switch (called_function->getIntrinsicID()) {
81     default:
82       break;
83     case llvm::Intrinsic::dbg_declare:
84     case llvm::Intrinsic::dbg_value:
85       return true;
86     }
87   }
88 
89   return false;
90 }
91 
92 class InterpreterStackFrame {
93 public:
94   typedef std::map<const Value *, lldb::addr_t> ValueMap;
95 
96   ValueMap m_values;
97   DataLayout &m_target_data;
98   lldb_private::IRExecutionUnit &m_execution_unit;
99   const BasicBlock *m_bb;
100   const BasicBlock *m_prev_bb;
101   BasicBlock::const_iterator m_ii;
102   BasicBlock::const_iterator m_ie;
103 
104   lldb::addr_t m_frame_process_address;
105   size_t m_frame_size;
106   lldb::addr_t m_stack_pointer;
107 
108   lldb::ByteOrder m_byte_order;
109   size_t m_addr_byte_size;
110 
111   InterpreterStackFrame(DataLayout &target_data,
112                         lldb_private::IRExecutionUnit &execution_unit,
113                         lldb::addr_t stack_frame_bottom,
114                         lldb::addr_t stack_frame_top)
115       : m_target_data(target_data), m_execution_unit(execution_unit),
116         m_bb(nullptr), m_prev_bb(nullptr) {
117     m_byte_order = (target_data.isLittleEndian() ? lldb::eByteOrderLittle
118                                                  : lldb::eByteOrderBig);
119     m_addr_byte_size = (target_data.getPointerSize(0));
120 
121     m_frame_process_address = stack_frame_bottom;
122     m_frame_size = stack_frame_top - stack_frame_bottom;
123     m_stack_pointer = stack_frame_top;
124   }
125 
126   ~InterpreterStackFrame() {}
127 
128   void Jump(const BasicBlock *bb) {
129     m_prev_bb = m_bb;
130     m_bb = bb;
131     m_ii = m_bb->begin();
132     m_ie = m_bb->end();
133   }
134 
135   std::string SummarizeValue(const Value *value) {
136     lldb_private::StreamString ss;
137 
138     ss.Printf("%s", PrintValue(value).c_str());
139 
140     ValueMap::iterator i = m_values.find(value);
141 
142     if (i != m_values.end()) {
143       lldb::addr_t addr = i->second;
144 
145       ss.Printf(" 0x%llx", (unsigned long long)addr);
146     }
147 
148     return ss.GetString();
149   }
150 
151   bool AssignToMatchType(lldb_private::Scalar &scalar, uint64_t u64value,
152                          Type *type) {
153     size_t type_size = m_target_data.getTypeStoreSize(type);
154 
155     if (type_size > 8)
156       return false;
157 
158     if (type_size != 1)
159       type_size = PowerOf2Ceil(type_size);
160 
161     scalar = llvm::APInt(type_size*8, u64value);
162     return true;
163   }
164 
165   bool EvaluateValue(lldb_private::Scalar &scalar, const Value *value,
166                      Module &module) {
167     const Constant *constant = dyn_cast<Constant>(value);
168 
169     if (constant) {
170       APInt value_apint;
171 
172       if (!ResolveConstantValue(value_apint, constant))
173         return false;
174 
175       return AssignToMatchType(scalar, value_apint.getLimitedValue(),
176                                value->getType());
177     } else {
178       lldb::addr_t process_address = ResolveValue(value, module);
179       size_t value_size = m_target_data.getTypeStoreSize(value->getType());
180 
181       lldb_private::DataExtractor value_extractor;
182       lldb_private::Status extract_error;
183 
184       m_execution_unit.GetMemoryData(value_extractor, process_address,
185                                      value_size, extract_error);
186 
187       if (!extract_error.Success())
188         return false;
189 
190       lldb::offset_t offset = 0;
191       if (value_size <= 8) {
192         uint64_t u64value = value_extractor.GetMaxU64(&offset, value_size);
193         return AssignToMatchType(scalar, u64value, value->getType());
194       }
195     }
196 
197     return false;
198   }
199 
200   bool AssignValue(const Value *value, lldb_private::Scalar &scalar,
201                    Module &module) {
202     lldb::addr_t process_address = ResolveValue(value, module);
203 
204     if (process_address == LLDB_INVALID_ADDRESS)
205       return false;
206 
207     lldb_private::Scalar cast_scalar;
208 
209     if (!AssignToMatchType(cast_scalar, scalar.ULongLong(), value->getType()))
210       return false;
211 
212     size_t value_byte_size = m_target_data.getTypeStoreSize(value->getType());
213 
214     lldb_private::DataBufferHeap buf(value_byte_size, 0);
215 
216     lldb_private::Status get_data_error;
217 
218     if (!cast_scalar.GetAsMemoryData(buf.GetBytes(), buf.GetByteSize(),
219                                      m_byte_order, get_data_error))
220       return false;
221 
222     lldb_private::Status write_error;
223 
224     m_execution_unit.WriteMemory(process_address, buf.GetBytes(),
225                                  buf.GetByteSize(), write_error);
226 
227     return write_error.Success();
228   }
229 
230   bool ResolveConstantValue(APInt &value, const Constant *constant) {
231     switch (constant->getValueID()) {
232     default:
233       break;
234     case Value::FunctionVal:
235       if (const Function *constant_func = dyn_cast<Function>(constant)) {
236         lldb_private::ConstString name(constant_func->getName());
237         lldb::addr_t addr = m_execution_unit.FindSymbol(name);
238         if (addr == LLDB_INVALID_ADDRESS)
239           return false;
240         value = APInt(m_target_data.getPointerSizeInBits(), addr);
241         return true;
242       }
243       break;
244     case Value::ConstantIntVal:
245       if (const ConstantInt *constant_int = dyn_cast<ConstantInt>(constant)) {
246         value = constant_int->getValue();
247         return true;
248       }
249       break;
250     case Value::ConstantFPVal:
251       if (const ConstantFP *constant_fp = dyn_cast<ConstantFP>(constant)) {
252         value = constant_fp->getValueAPF().bitcastToAPInt();
253         return true;
254       }
255       break;
256     case Value::ConstantExprVal:
257       if (const ConstantExpr *constant_expr =
258               dyn_cast<ConstantExpr>(constant)) {
259         switch (constant_expr->getOpcode()) {
260         default:
261           return false;
262         case Instruction::IntToPtr:
263         case Instruction::PtrToInt:
264         case Instruction::BitCast:
265           return ResolveConstantValue(value, constant_expr->getOperand(0));
266         case Instruction::GetElementPtr: {
267           ConstantExpr::const_op_iterator op_cursor = constant_expr->op_begin();
268           ConstantExpr::const_op_iterator op_end = constant_expr->op_end();
269 
270           Constant *base = dyn_cast<Constant>(*op_cursor);
271 
272           if (!base)
273             return false;
274 
275           if (!ResolveConstantValue(value, base))
276             return false;
277 
278           op_cursor++;
279 
280           if (op_cursor == op_end)
281             return true; // no offset to apply!
282 
283           SmallVector<Value *, 8> indices(op_cursor, op_end);
284 
285           Type *src_elem_ty =
286               cast<GEPOperator>(constant_expr)->getSourceElementType();
287           uint64_t offset =
288               m_target_data.getIndexedOffsetInType(src_elem_ty, indices);
289 
290           const bool is_signed = true;
291           value += APInt(value.getBitWidth(), offset, is_signed);
292 
293           return true;
294         }
295         }
296       }
297       break;
298     case Value::ConstantPointerNullVal:
299       if (isa<ConstantPointerNull>(constant)) {
300         value = APInt(m_target_data.getPointerSizeInBits(), 0);
301         return true;
302       }
303       break;
304     }
305     return false;
306   }
307 
308   bool MakeArgument(const Argument *value, uint64_t address) {
309     lldb::addr_t data_address = Malloc(value->getType());
310 
311     if (data_address == LLDB_INVALID_ADDRESS)
312       return false;
313 
314     lldb_private::Status write_error;
315 
316     m_execution_unit.WritePointerToMemory(data_address, address, write_error);
317 
318     if (!write_error.Success()) {
319       lldb_private::Status free_error;
320       m_execution_unit.Free(data_address, free_error);
321       return false;
322     }
323 
324     m_values[value] = data_address;
325 
326     lldb_private::Log *log(
327         lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
328 
329     if (log) {
330       log->Printf("Made an allocation for argument %s",
331                   PrintValue(value).c_str());
332       log->Printf("  Data region    : %llx", (unsigned long long)address);
333       log->Printf("  Ref region     : %llx", (unsigned long long)data_address);
334     }
335 
336     return true;
337   }
338 
339   bool ResolveConstant(lldb::addr_t process_address, const Constant *constant) {
340     APInt resolved_value;
341 
342     if (!ResolveConstantValue(resolved_value, constant))
343       return false;
344 
345     size_t constant_size = m_target_data.getTypeStoreSize(constant->getType());
346     lldb_private::DataBufferHeap buf(constant_size, 0);
347 
348     lldb_private::Status get_data_error;
349 
350     lldb_private::Scalar resolved_scalar(
351         resolved_value.zextOrTrunc(llvm::NextPowerOf2(constant_size) * 8));
352     if (!resolved_scalar.GetAsMemoryData(buf.GetBytes(), buf.GetByteSize(),
353                                          m_byte_order, get_data_error))
354       return false;
355 
356     lldb_private::Status write_error;
357 
358     m_execution_unit.WriteMemory(process_address, buf.GetBytes(),
359                                  buf.GetByteSize(), write_error);
360 
361     return write_error.Success();
362   }
363 
364   lldb::addr_t Malloc(size_t size, uint8_t byte_alignment) {
365     lldb::addr_t ret = m_stack_pointer;
366 
367     ret -= size;
368     ret -= (ret % byte_alignment);
369 
370     if (ret < m_frame_process_address)
371       return LLDB_INVALID_ADDRESS;
372 
373     m_stack_pointer = ret;
374     return ret;
375   }
376 
377   lldb::addr_t Malloc(llvm::Type *type) {
378     lldb_private::Status alloc_error;
379 
380     return Malloc(m_target_data.getTypeAllocSize(type),
381                   m_target_data.getPrefTypeAlignment(type));
382   }
383 
384   std::string PrintData(lldb::addr_t addr, llvm::Type *type) {
385     size_t length = m_target_data.getTypeStoreSize(type);
386 
387     lldb_private::DataBufferHeap buf(length, 0);
388 
389     lldb_private::Status read_error;
390 
391     m_execution_unit.ReadMemory(buf.GetBytes(), addr, length, read_error);
392 
393     if (!read_error.Success())
394       return std::string("<couldn't read data>");
395 
396     lldb_private::StreamString ss;
397 
398     for (size_t i = 0; i < length; i++) {
399       if ((!(i & 0xf)) && i)
400         ss.Printf("%02hhx - ", buf.GetBytes()[i]);
401       else
402         ss.Printf("%02hhx ", buf.GetBytes()[i]);
403     }
404 
405     return ss.GetString();
406   }
407 
408   lldb::addr_t ResolveValue(const Value *value, Module &module) {
409     ValueMap::iterator i = m_values.find(value);
410 
411     if (i != m_values.end())
412       return i->second;
413 
414     // Fall back and allocate space [allocation type Alloca]
415 
416     lldb::addr_t data_address = Malloc(value->getType());
417 
418     if (const Constant *constant = dyn_cast<Constant>(value)) {
419       if (!ResolveConstant(data_address, constant)) {
420         lldb_private::Status free_error;
421         m_execution_unit.Free(data_address, free_error);
422         return LLDB_INVALID_ADDRESS;
423       }
424     }
425 
426     m_values[value] = data_address;
427     return data_address;
428   }
429 };
430 
431 static const char *unsupported_opcode_error =
432     "Interpreter doesn't handle one of the expression's opcodes";
433 static const char *unsupported_operand_error =
434     "Interpreter doesn't handle one of the expression's operands";
435 // static const char *interpreter_initialization_error = "Interpreter couldn't
436 // be initialized";
437 static const char *interpreter_internal_error =
438     "Interpreter encountered an internal error";
439 static const char *bad_value_error =
440     "Interpreter couldn't resolve a value during execution";
441 static const char *memory_allocation_error =
442     "Interpreter couldn't allocate memory";
443 static const char *memory_write_error = "Interpreter couldn't write to memory";
444 static const char *memory_read_error = "Interpreter couldn't read from memory";
445 static const char *infinite_loop_error = "Interpreter ran for too many cycles";
446 // static const char *bad_result_error                 = "Result of expression
447 // is in bad memory";
448 static const char *too_many_functions_error =
449     "Interpreter doesn't handle modules with multiple function bodies.";
450 
451 static bool CanResolveConstant(llvm::Constant *constant) {
452   switch (constant->getValueID()) {
453   default:
454     return false;
455   case Value::ConstantIntVal:
456   case Value::ConstantFPVal:
457   case Value::FunctionVal:
458     return true;
459   case Value::ConstantExprVal:
460     if (const ConstantExpr *constant_expr = dyn_cast<ConstantExpr>(constant)) {
461       switch (constant_expr->getOpcode()) {
462       default:
463         return false;
464       case Instruction::IntToPtr:
465       case Instruction::PtrToInt:
466       case Instruction::BitCast:
467         return CanResolveConstant(constant_expr->getOperand(0));
468       case Instruction::GetElementPtr: {
469         ConstantExpr::const_op_iterator op_cursor = constant_expr->op_begin();
470         Constant *base = dyn_cast<Constant>(*op_cursor);
471         if (!base)
472           return false;
473 
474         return CanResolveConstant(base);
475       }
476       }
477     } else {
478       return false;
479     }
480   case Value::ConstantPointerNullVal:
481     return true;
482   }
483 }
484 
485 bool IRInterpreter::CanInterpret(llvm::Module &module, llvm::Function &function,
486                                  lldb_private::Status &error,
487                                  const bool support_function_calls) {
488   lldb_private::Log *log(
489       lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
490 
491   bool saw_function_with_body = false;
492 
493   for (Module::iterator fi = module.begin(), fe = module.end(); fi != fe;
494        ++fi) {
495     if (fi->begin() != fi->end()) {
496       if (saw_function_with_body) {
497         if (log)
498           log->Printf("More than one function in the module has a body");
499         error.SetErrorToGenericError();
500         error.SetErrorString(too_many_functions_error);
501         return false;
502       }
503       saw_function_with_body = true;
504     }
505   }
506 
507   for (Function::iterator bbi = function.begin(), bbe = function.end();
508        bbi != bbe; ++bbi) {
509     for (BasicBlock::iterator ii = bbi->begin(), ie = bbi->end(); ii != ie;
510          ++ii) {
511       switch (ii->getOpcode()) {
512       default: {
513         if (log)
514           log->Printf("Unsupported instruction: %s", PrintValue(&*ii).c_str());
515         error.SetErrorToGenericError();
516         error.SetErrorString(unsupported_opcode_error);
517         return false;
518       }
519       case Instruction::Add:
520       case Instruction::Alloca:
521       case Instruction::BitCast:
522       case Instruction::Br:
523       case Instruction::PHI:
524         break;
525       case Instruction::Call: {
526         CallInst *call_inst = dyn_cast<CallInst>(ii);
527 
528         if (!call_inst) {
529           error.SetErrorToGenericError();
530           error.SetErrorString(interpreter_internal_error);
531           return false;
532         }
533 
534         if (!CanIgnoreCall(call_inst) && !support_function_calls) {
535           if (log)
536             log->Printf("Unsupported instruction: %s",
537                         PrintValue(&*ii).c_str());
538           error.SetErrorToGenericError();
539           error.SetErrorString(unsupported_opcode_error);
540           return false;
541         }
542       } break;
543       case Instruction::GetElementPtr:
544         break;
545       case Instruction::ICmp: {
546         ICmpInst *icmp_inst = dyn_cast<ICmpInst>(ii);
547 
548         if (!icmp_inst) {
549           error.SetErrorToGenericError();
550           error.SetErrorString(interpreter_internal_error);
551           return false;
552         }
553 
554         switch (icmp_inst->getPredicate()) {
555         default: {
556           if (log)
557             log->Printf("Unsupported ICmp predicate: %s",
558                         PrintValue(&*ii).c_str());
559 
560           error.SetErrorToGenericError();
561           error.SetErrorString(unsupported_opcode_error);
562           return false;
563         }
564         case CmpInst::ICMP_EQ:
565         case CmpInst::ICMP_NE:
566         case CmpInst::ICMP_UGT:
567         case CmpInst::ICMP_UGE:
568         case CmpInst::ICMP_ULT:
569         case CmpInst::ICMP_ULE:
570         case CmpInst::ICMP_SGT:
571         case CmpInst::ICMP_SGE:
572         case CmpInst::ICMP_SLT:
573         case CmpInst::ICMP_SLE:
574           break;
575         }
576       } break;
577       case Instruction::And:
578       case Instruction::AShr:
579       case Instruction::IntToPtr:
580       case Instruction::PtrToInt:
581       case Instruction::Load:
582       case Instruction::LShr:
583       case Instruction::Mul:
584       case Instruction::Or:
585       case Instruction::Ret:
586       case Instruction::SDiv:
587       case Instruction::SExt:
588       case Instruction::Shl:
589       case Instruction::SRem:
590       case Instruction::Store:
591       case Instruction::Sub:
592       case Instruction::Trunc:
593       case Instruction::UDiv:
594       case Instruction::URem:
595       case Instruction::Xor:
596       case Instruction::ZExt:
597         break;
598       }
599 
600       for (int oi = 0, oe = ii->getNumOperands(); oi != oe; ++oi) {
601         Value *operand = ii->getOperand(oi);
602         Type *operand_type = operand->getType();
603 
604         switch (operand_type->getTypeID()) {
605         default:
606           break;
607         case Type::VectorTyID: {
608           if (log)
609             log->Printf("Unsupported operand type: %s",
610                         PrintType(operand_type).c_str());
611           error.SetErrorString(unsupported_operand_error);
612           return false;
613         }
614         }
615 
616         if (Constant *constant = llvm::dyn_cast<Constant>(operand)) {
617           if (!CanResolveConstant(constant)) {
618             if (log)
619               log->Printf("Unsupported constant: %s",
620                           PrintValue(constant).c_str());
621             error.SetErrorString(unsupported_operand_error);
622             return false;
623           }
624         }
625       }
626     }
627   }
628 
629   return true;
630 }
631 
632 bool IRInterpreter::Interpret(llvm::Module &module, llvm::Function &function,
633                               llvm::ArrayRef<lldb::addr_t> args,
634                               lldb_private::IRExecutionUnit &execution_unit,
635                               lldb_private::Status &error,
636                               lldb::addr_t stack_frame_bottom,
637                               lldb::addr_t stack_frame_top,
638                               lldb_private::ExecutionContext &exe_ctx) {
639   lldb_private::Log *log(
640       lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
641 
642   if (log) {
643     std::string s;
644     raw_string_ostream oss(s);
645 
646     module.print(oss, NULL);
647 
648     oss.flush();
649 
650     log->Printf("Module as passed in to IRInterpreter::Interpret: \n\"%s\"",
651                 s.c_str());
652   }
653 
654   DataLayout data_layout(&module);
655 
656   InterpreterStackFrame frame(data_layout, execution_unit, stack_frame_bottom,
657                               stack_frame_top);
658 
659   if (frame.m_frame_process_address == LLDB_INVALID_ADDRESS) {
660     error.SetErrorString("Couldn't allocate stack frame");
661   }
662 
663   int arg_index = 0;
664 
665   for (llvm::Function::arg_iterator ai = function.arg_begin(),
666                                     ae = function.arg_end();
667        ai != ae; ++ai, ++arg_index) {
668     if (args.size() <= static_cast<size_t>(arg_index)) {
669       error.SetErrorString("Not enough arguments passed in to function");
670       return false;
671     }
672 
673     lldb::addr_t ptr = args[arg_index];
674 
675     frame.MakeArgument(&*ai, ptr);
676   }
677 
678   uint32_t num_insts = 0;
679 
680   frame.Jump(&function.front());
681 
682   while (frame.m_ii != frame.m_ie && (++num_insts < 4096)) {
683     const Instruction *inst = &*frame.m_ii;
684 
685     if (log)
686       log->Printf("Interpreting %s", PrintValue(inst).c_str());
687 
688     switch (inst->getOpcode()) {
689     default:
690       break;
691 
692     case Instruction::Add:
693     case Instruction::Sub:
694     case Instruction::Mul:
695     case Instruction::SDiv:
696     case Instruction::UDiv:
697     case Instruction::SRem:
698     case Instruction::URem:
699     case Instruction::Shl:
700     case Instruction::LShr:
701     case Instruction::AShr:
702     case Instruction::And:
703     case Instruction::Or:
704     case Instruction::Xor: {
705       const BinaryOperator *bin_op = dyn_cast<BinaryOperator>(inst);
706 
707       if (!bin_op) {
708         if (log)
709           log->Printf(
710               "getOpcode() returns %s, but instruction is not a BinaryOperator",
711               inst->getOpcodeName());
712         error.SetErrorToGenericError();
713         error.SetErrorString(interpreter_internal_error);
714         return false;
715       }
716 
717       Value *lhs = inst->getOperand(0);
718       Value *rhs = inst->getOperand(1);
719 
720       lldb_private::Scalar L;
721       lldb_private::Scalar R;
722 
723       if (!frame.EvaluateValue(L, lhs, module)) {
724         if (log)
725           log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
726         error.SetErrorToGenericError();
727         error.SetErrorString(bad_value_error);
728         return false;
729       }
730 
731       if (!frame.EvaluateValue(R, rhs, module)) {
732         if (log)
733           log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
734         error.SetErrorToGenericError();
735         error.SetErrorString(bad_value_error);
736         return false;
737       }
738 
739       lldb_private::Scalar result;
740 
741       switch (inst->getOpcode()) {
742       default:
743         break;
744       case Instruction::Add:
745         result = L + R;
746         break;
747       case Instruction::Mul:
748         result = L * R;
749         break;
750       case Instruction::Sub:
751         result = L - R;
752         break;
753       case Instruction::SDiv:
754         L.MakeSigned();
755         R.MakeSigned();
756         result = L / R;
757         break;
758       case Instruction::UDiv:
759         L.MakeUnsigned();
760         R.MakeUnsigned();
761         result = L / R;
762         break;
763       case Instruction::SRem:
764         L.MakeSigned();
765         R.MakeSigned();
766         result = L % R;
767         break;
768       case Instruction::URem:
769         L.MakeUnsigned();
770         R.MakeUnsigned();
771         result = L % R;
772         break;
773       case Instruction::Shl:
774         result = L << R;
775         break;
776       case Instruction::AShr:
777         result = L >> R;
778         break;
779       case Instruction::LShr:
780         result = L;
781         result.ShiftRightLogical(R);
782         break;
783       case Instruction::And:
784         result = L & R;
785         break;
786       case Instruction::Or:
787         result = L | R;
788         break;
789       case Instruction::Xor:
790         result = L ^ R;
791         break;
792       }
793 
794       frame.AssignValue(inst, result, module);
795 
796       if (log) {
797         log->Printf("Interpreted a %s", inst->getOpcodeName());
798         log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
799         log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
800         log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
801       }
802     } break;
803     case Instruction::Alloca: {
804       const AllocaInst *alloca_inst = dyn_cast<AllocaInst>(inst);
805 
806       if (!alloca_inst) {
807         if (log)
808           log->Printf("getOpcode() returns Alloca, but instruction is not an "
809                       "AllocaInst");
810         error.SetErrorToGenericError();
811         error.SetErrorString(interpreter_internal_error);
812         return false;
813       }
814 
815       if (alloca_inst->isArrayAllocation()) {
816         if (log)
817           log->Printf(
818               "AllocaInsts are not handled if isArrayAllocation() is true");
819         error.SetErrorToGenericError();
820         error.SetErrorString(unsupported_opcode_error);
821         return false;
822       }
823 
824       // The semantics of Alloca are:
825       //   Create a region R of virtual memory of type T, backed by a data
826       //   buffer
827       //   Create a region P of virtual memory of type T*, backed by a data
828       //   buffer
829       //   Write the virtual address of R into P
830 
831       Type *T = alloca_inst->getAllocatedType();
832       Type *Tptr = alloca_inst->getType();
833 
834       lldb::addr_t R = frame.Malloc(T);
835 
836       if (R == LLDB_INVALID_ADDRESS) {
837         if (log)
838           log->Printf("Couldn't allocate memory for an AllocaInst");
839         error.SetErrorToGenericError();
840         error.SetErrorString(memory_allocation_error);
841         return false;
842       }
843 
844       lldb::addr_t P = frame.Malloc(Tptr);
845 
846       if (P == LLDB_INVALID_ADDRESS) {
847         if (log)
848           log->Printf("Couldn't allocate the result pointer for an AllocaInst");
849         error.SetErrorToGenericError();
850         error.SetErrorString(memory_allocation_error);
851         return false;
852       }
853 
854       lldb_private::Status write_error;
855 
856       execution_unit.WritePointerToMemory(P, R, write_error);
857 
858       if (!write_error.Success()) {
859         if (log)
860           log->Printf("Couldn't write the result pointer for an AllocaInst");
861         error.SetErrorToGenericError();
862         error.SetErrorString(memory_write_error);
863         lldb_private::Status free_error;
864         execution_unit.Free(P, free_error);
865         execution_unit.Free(R, free_error);
866         return false;
867       }
868 
869       frame.m_values[alloca_inst] = P;
870 
871       if (log) {
872         log->Printf("Interpreted an AllocaInst");
873         log->Printf("  R : 0x%" PRIx64, R);
874         log->Printf("  P : 0x%" PRIx64, P);
875       }
876     } break;
877     case Instruction::BitCast:
878     case Instruction::ZExt: {
879       const CastInst *cast_inst = dyn_cast<CastInst>(inst);
880 
881       if (!cast_inst) {
882         if (log)
883           log->Printf(
884               "getOpcode() returns %s, but instruction is not a BitCastInst",
885               cast_inst->getOpcodeName());
886         error.SetErrorToGenericError();
887         error.SetErrorString(interpreter_internal_error);
888         return false;
889       }
890 
891       Value *source = cast_inst->getOperand(0);
892 
893       lldb_private::Scalar S;
894 
895       if (!frame.EvaluateValue(S, source, module)) {
896         if (log)
897           log->Printf("Couldn't evaluate %s", PrintValue(source).c_str());
898         error.SetErrorToGenericError();
899         error.SetErrorString(bad_value_error);
900         return false;
901       }
902 
903       frame.AssignValue(inst, S, module);
904     } break;
905     case Instruction::SExt: {
906       const CastInst *cast_inst = dyn_cast<CastInst>(inst);
907 
908       if (!cast_inst) {
909         if (log)
910           log->Printf(
911               "getOpcode() returns %s, but instruction is not a BitCastInst",
912               cast_inst->getOpcodeName());
913         error.SetErrorToGenericError();
914         error.SetErrorString(interpreter_internal_error);
915         return false;
916       }
917 
918       Value *source = cast_inst->getOperand(0);
919 
920       lldb_private::Scalar S;
921 
922       if (!frame.EvaluateValue(S, source, module)) {
923         if (log)
924           log->Printf("Couldn't evaluate %s", PrintValue(source).c_str());
925         error.SetErrorToGenericError();
926         error.SetErrorString(bad_value_error);
927         return false;
928       }
929 
930       S.MakeSigned();
931 
932       lldb_private::Scalar S_signextend(S.SLongLong());
933 
934       frame.AssignValue(inst, S_signextend, module);
935     } break;
936     case Instruction::Br: {
937       const BranchInst *br_inst = dyn_cast<BranchInst>(inst);
938 
939       if (!br_inst) {
940         if (log)
941           log->Printf(
942               "getOpcode() returns Br, but instruction is not a BranchInst");
943         error.SetErrorToGenericError();
944         error.SetErrorString(interpreter_internal_error);
945         return false;
946       }
947 
948       if (br_inst->isConditional()) {
949         Value *condition = br_inst->getCondition();
950 
951         lldb_private::Scalar C;
952 
953         if (!frame.EvaluateValue(C, condition, module)) {
954           if (log)
955             log->Printf("Couldn't evaluate %s", PrintValue(condition).c_str());
956           error.SetErrorToGenericError();
957           error.SetErrorString(bad_value_error);
958           return false;
959         }
960 
961         if (!C.IsZero())
962           frame.Jump(br_inst->getSuccessor(0));
963         else
964           frame.Jump(br_inst->getSuccessor(1));
965 
966         if (log) {
967           log->Printf("Interpreted a BrInst with a condition");
968           log->Printf("  cond : %s", frame.SummarizeValue(condition).c_str());
969         }
970       } else {
971         frame.Jump(br_inst->getSuccessor(0));
972 
973         if (log) {
974           log->Printf("Interpreted a BrInst with no condition");
975         }
976       }
977     }
978       continue;
979     case Instruction::PHI: {
980       const PHINode *phi_inst = dyn_cast<PHINode>(inst);
981 
982       if (!phi_inst) {
983         if (log)
984           log->Printf(
985               "getOpcode() returns PHI, but instruction is not a PHINode");
986         error.SetErrorToGenericError();
987         error.SetErrorString(interpreter_internal_error);
988         return false;
989       }
990       if (!frame.m_prev_bb) {
991         if (log)
992           log->Printf("Encountered PHI node without having jumped from another "
993                       "basic block");
994         error.SetErrorToGenericError();
995         error.SetErrorString(interpreter_internal_error);
996         return false;
997       }
998 
999       Value *value = phi_inst->getIncomingValueForBlock(frame.m_prev_bb);
1000       lldb_private::Scalar result;
1001       if (!frame.EvaluateValue(result, value, module)) {
1002         if (log)
1003           log->Printf("Couldn't evaluate %s", PrintValue(value).c_str());
1004         error.SetErrorToGenericError();
1005         error.SetErrorString(bad_value_error);
1006         return false;
1007       }
1008       frame.AssignValue(inst, result, module);
1009 
1010       if (log) {
1011         log->Printf("Interpreted a %s", inst->getOpcodeName());
1012         log->Printf("  Incoming value : %s",
1013                     frame.SummarizeValue(value).c_str());
1014       }
1015     } break;
1016     case Instruction::GetElementPtr: {
1017       const GetElementPtrInst *gep_inst = dyn_cast<GetElementPtrInst>(inst);
1018 
1019       if (!gep_inst) {
1020         if (log)
1021           log->Printf("getOpcode() returns GetElementPtr, but instruction is "
1022                       "not a GetElementPtrInst");
1023         error.SetErrorToGenericError();
1024         error.SetErrorString(interpreter_internal_error);
1025         return false;
1026       }
1027 
1028       const Value *pointer_operand = gep_inst->getPointerOperand();
1029       Type *src_elem_ty = gep_inst->getSourceElementType();
1030 
1031       lldb_private::Scalar P;
1032 
1033       if (!frame.EvaluateValue(P, pointer_operand, module)) {
1034         if (log)
1035           log->Printf("Couldn't evaluate %s",
1036                       PrintValue(pointer_operand).c_str());
1037         error.SetErrorToGenericError();
1038         error.SetErrorString(bad_value_error);
1039         return false;
1040       }
1041 
1042       typedef SmallVector<Value *, 8> IndexVector;
1043       typedef IndexVector::iterator IndexIterator;
1044 
1045       SmallVector<Value *, 8> indices(gep_inst->idx_begin(),
1046                                       gep_inst->idx_end());
1047 
1048       SmallVector<Value *, 8> const_indices;
1049 
1050       for (IndexIterator ii = indices.begin(), ie = indices.end(); ii != ie;
1051            ++ii) {
1052         ConstantInt *constant_index = dyn_cast<ConstantInt>(*ii);
1053 
1054         if (!constant_index) {
1055           lldb_private::Scalar I;
1056 
1057           if (!frame.EvaluateValue(I, *ii, module)) {
1058             if (log)
1059               log->Printf("Couldn't evaluate %s", PrintValue(*ii).c_str());
1060             error.SetErrorToGenericError();
1061             error.SetErrorString(bad_value_error);
1062             return false;
1063           }
1064 
1065           if (log)
1066             log->Printf("Evaluated constant index %s as %llu",
1067                         PrintValue(*ii).c_str(),
1068                         I.ULongLong(LLDB_INVALID_ADDRESS));
1069 
1070           constant_index = cast<ConstantInt>(ConstantInt::get(
1071               (*ii)->getType(), I.ULongLong(LLDB_INVALID_ADDRESS)));
1072         }
1073 
1074         const_indices.push_back(constant_index);
1075       }
1076 
1077       uint64_t offset =
1078           data_layout.getIndexedOffsetInType(src_elem_ty, const_indices);
1079 
1080       lldb_private::Scalar Poffset = P + offset;
1081 
1082       frame.AssignValue(inst, Poffset, module);
1083 
1084       if (log) {
1085         log->Printf("Interpreted a GetElementPtrInst");
1086         log->Printf("  P       : %s",
1087                     frame.SummarizeValue(pointer_operand).c_str());
1088         log->Printf("  Poffset : %s", frame.SummarizeValue(inst).c_str());
1089       }
1090     } break;
1091     case Instruction::ICmp: {
1092       const ICmpInst *icmp_inst = dyn_cast<ICmpInst>(inst);
1093 
1094       if (!icmp_inst) {
1095         if (log)
1096           log->Printf(
1097               "getOpcode() returns ICmp, but instruction is not an ICmpInst");
1098         error.SetErrorToGenericError();
1099         error.SetErrorString(interpreter_internal_error);
1100         return false;
1101       }
1102 
1103       CmpInst::Predicate predicate = icmp_inst->getPredicate();
1104 
1105       Value *lhs = inst->getOperand(0);
1106       Value *rhs = inst->getOperand(1);
1107 
1108       lldb_private::Scalar L;
1109       lldb_private::Scalar R;
1110 
1111       if (!frame.EvaluateValue(L, lhs, module)) {
1112         if (log)
1113           log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
1114         error.SetErrorToGenericError();
1115         error.SetErrorString(bad_value_error);
1116         return false;
1117       }
1118 
1119       if (!frame.EvaluateValue(R, rhs, module)) {
1120         if (log)
1121           log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
1122         error.SetErrorToGenericError();
1123         error.SetErrorString(bad_value_error);
1124         return false;
1125       }
1126 
1127       lldb_private::Scalar result;
1128 
1129       switch (predicate) {
1130       default:
1131         return false;
1132       case CmpInst::ICMP_EQ:
1133         result = (L == R);
1134         break;
1135       case CmpInst::ICMP_NE:
1136         result = (L != R);
1137         break;
1138       case CmpInst::ICMP_UGT:
1139         L.MakeUnsigned();
1140         R.MakeUnsigned();
1141         result = (L > R);
1142         break;
1143       case CmpInst::ICMP_UGE:
1144         L.MakeUnsigned();
1145         R.MakeUnsigned();
1146         result = (L >= R);
1147         break;
1148       case CmpInst::ICMP_ULT:
1149         L.MakeUnsigned();
1150         R.MakeUnsigned();
1151         result = (L < R);
1152         break;
1153       case CmpInst::ICMP_ULE:
1154         L.MakeUnsigned();
1155         R.MakeUnsigned();
1156         result = (L <= R);
1157         break;
1158       case CmpInst::ICMP_SGT:
1159         L.MakeSigned();
1160         R.MakeSigned();
1161         result = (L > R);
1162         break;
1163       case CmpInst::ICMP_SGE:
1164         L.MakeSigned();
1165         R.MakeSigned();
1166         result = (L >= R);
1167         break;
1168       case CmpInst::ICMP_SLT:
1169         L.MakeSigned();
1170         R.MakeSigned();
1171         result = (L < R);
1172         break;
1173       case CmpInst::ICMP_SLE:
1174         L.MakeSigned();
1175         R.MakeSigned();
1176         result = (L <= R);
1177         break;
1178       }
1179 
1180       frame.AssignValue(inst, result, module);
1181 
1182       if (log) {
1183         log->Printf("Interpreted an ICmpInst");
1184         log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
1185         log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
1186         log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
1187       }
1188     } break;
1189     case Instruction::IntToPtr: {
1190       const IntToPtrInst *int_to_ptr_inst = dyn_cast<IntToPtrInst>(inst);
1191 
1192       if (!int_to_ptr_inst) {
1193         if (log)
1194           log->Printf("getOpcode() returns IntToPtr, but instruction is not an "
1195                       "IntToPtrInst");
1196         error.SetErrorToGenericError();
1197         error.SetErrorString(interpreter_internal_error);
1198         return false;
1199       }
1200 
1201       Value *src_operand = int_to_ptr_inst->getOperand(0);
1202 
1203       lldb_private::Scalar I;
1204 
1205       if (!frame.EvaluateValue(I, src_operand, module)) {
1206         if (log)
1207           log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
1208         error.SetErrorToGenericError();
1209         error.SetErrorString(bad_value_error);
1210         return false;
1211       }
1212 
1213       frame.AssignValue(inst, I, module);
1214 
1215       if (log) {
1216         log->Printf("Interpreted an IntToPtr");
1217         log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1218         log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1219       }
1220     } break;
1221     case Instruction::PtrToInt: {
1222       const PtrToIntInst *ptr_to_int_inst = dyn_cast<PtrToIntInst>(inst);
1223 
1224       if (!ptr_to_int_inst) {
1225         if (log)
1226           log->Printf("getOpcode() returns PtrToInt, but instruction is not an "
1227                       "PtrToIntInst");
1228         error.SetErrorToGenericError();
1229         error.SetErrorString(interpreter_internal_error);
1230         return false;
1231       }
1232 
1233       Value *src_operand = ptr_to_int_inst->getOperand(0);
1234 
1235       lldb_private::Scalar I;
1236 
1237       if (!frame.EvaluateValue(I, src_operand, module)) {
1238         if (log)
1239           log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
1240         error.SetErrorToGenericError();
1241         error.SetErrorString(bad_value_error);
1242         return false;
1243       }
1244 
1245       frame.AssignValue(inst, I, module);
1246 
1247       if (log) {
1248         log->Printf("Interpreted a PtrToInt");
1249         log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1250         log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1251       }
1252     } break;
1253     case Instruction::Trunc: {
1254       const TruncInst *trunc_inst = dyn_cast<TruncInst>(inst);
1255 
1256       if (!trunc_inst) {
1257         if (log)
1258           log->Printf(
1259               "getOpcode() returns Trunc, but instruction is not a TruncInst");
1260         error.SetErrorToGenericError();
1261         error.SetErrorString(interpreter_internal_error);
1262         return false;
1263       }
1264 
1265       Value *src_operand = trunc_inst->getOperand(0);
1266 
1267       lldb_private::Scalar I;
1268 
1269       if (!frame.EvaluateValue(I, src_operand, module)) {
1270         if (log)
1271           log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
1272         error.SetErrorToGenericError();
1273         error.SetErrorString(bad_value_error);
1274         return false;
1275       }
1276 
1277       frame.AssignValue(inst, I, module);
1278 
1279       if (log) {
1280         log->Printf("Interpreted a Trunc");
1281         log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
1282         log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
1283       }
1284     } break;
1285     case Instruction::Load: {
1286       const LoadInst *load_inst = dyn_cast<LoadInst>(inst);
1287 
1288       if (!load_inst) {
1289         if (log)
1290           log->Printf(
1291               "getOpcode() returns Load, but instruction is not a LoadInst");
1292         error.SetErrorToGenericError();
1293         error.SetErrorString(interpreter_internal_error);
1294         return false;
1295       }
1296 
1297       // The semantics of Load are:
1298       //   Create a region D that will contain the loaded data
1299       //   Resolve the region P containing a pointer
1300       //   Dereference P to get the region R that the data should be loaded from
1301       //   Transfer a unit of type type(D) from R to D
1302 
1303       const Value *pointer_operand = load_inst->getPointerOperand();
1304 
1305       Type *pointer_ty = pointer_operand->getType();
1306       PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1307       if (!pointer_ptr_ty) {
1308         if (log)
1309           log->Printf("getPointerOperand()->getType() is not a PointerType");
1310         error.SetErrorToGenericError();
1311         error.SetErrorString(interpreter_internal_error);
1312         return false;
1313       }
1314       Type *target_ty = pointer_ptr_ty->getElementType();
1315 
1316       lldb::addr_t D = frame.ResolveValue(load_inst, module);
1317       lldb::addr_t P = frame.ResolveValue(pointer_operand, module);
1318 
1319       if (D == LLDB_INVALID_ADDRESS) {
1320         if (log)
1321           log->Printf("LoadInst's value doesn't resolve to anything");
1322         error.SetErrorToGenericError();
1323         error.SetErrorString(bad_value_error);
1324         return false;
1325       }
1326 
1327       if (P == LLDB_INVALID_ADDRESS) {
1328         if (log)
1329           log->Printf("LoadInst's pointer doesn't resolve to anything");
1330         error.SetErrorToGenericError();
1331         error.SetErrorString(bad_value_error);
1332         return false;
1333       }
1334 
1335       lldb::addr_t R;
1336       lldb_private::Status read_error;
1337       execution_unit.ReadPointerFromMemory(&R, P, read_error);
1338 
1339       if (!read_error.Success()) {
1340         if (log)
1341           log->Printf("Couldn't read the address to be loaded for a LoadInst");
1342         error.SetErrorToGenericError();
1343         error.SetErrorString(memory_read_error);
1344         return false;
1345       }
1346 
1347       size_t target_size = data_layout.getTypeStoreSize(target_ty);
1348       lldb_private::DataBufferHeap buffer(target_size, 0);
1349 
1350       read_error.Clear();
1351       execution_unit.ReadMemory(buffer.GetBytes(), R, buffer.GetByteSize(),
1352                                 read_error);
1353       if (!read_error.Success()) {
1354         if (log)
1355           log->Printf("Couldn't read from a region on behalf of a LoadInst");
1356         error.SetErrorToGenericError();
1357         error.SetErrorString(memory_read_error);
1358         return false;
1359       }
1360 
1361       lldb_private::Status write_error;
1362       execution_unit.WriteMemory(D, buffer.GetBytes(), buffer.GetByteSize(),
1363                                  write_error);
1364       if (!write_error.Success()) {
1365         if (log)
1366           log->Printf("Couldn't write to a region on behalf of a LoadInst");
1367         error.SetErrorToGenericError();
1368         error.SetErrorString(memory_read_error);
1369         return false;
1370       }
1371 
1372       if (log) {
1373         log->Printf("Interpreted a LoadInst");
1374         log->Printf("  P : 0x%" PRIx64, P);
1375         log->Printf("  R : 0x%" PRIx64, R);
1376         log->Printf("  D : 0x%" PRIx64, D);
1377       }
1378     } break;
1379     case Instruction::Ret: {
1380       return true;
1381     }
1382     case Instruction::Store: {
1383       const StoreInst *store_inst = dyn_cast<StoreInst>(inst);
1384 
1385       if (!store_inst) {
1386         if (log)
1387           log->Printf(
1388               "getOpcode() returns Store, but instruction is not a StoreInst");
1389         error.SetErrorToGenericError();
1390         error.SetErrorString(interpreter_internal_error);
1391         return false;
1392       }
1393 
1394       // The semantics of Store are:
1395       //   Resolve the region D containing the data to be stored
1396       //   Resolve the region P containing a pointer
1397       //   Dereference P to get the region R that the data should be stored in
1398       //   Transfer a unit of type type(D) from D to R
1399 
1400       const Value *value_operand = store_inst->getValueOperand();
1401       const Value *pointer_operand = store_inst->getPointerOperand();
1402 
1403       Type *pointer_ty = pointer_operand->getType();
1404       PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
1405       if (!pointer_ptr_ty)
1406         return false;
1407       Type *target_ty = pointer_ptr_ty->getElementType();
1408 
1409       lldb::addr_t D = frame.ResolveValue(value_operand, module);
1410       lldb::addr_t P = frame.ResolveValue(pointer_operand, module);
1411 
1412       if (D == LLDB_INVALID_ADDRESS) {
1413         if (log)
1414           log->Printf("StoreInst's value doesn't resolve to anything");
1415         error.SetErrorToGenericError();
1416         error.SetErrorString(bad_value_error);
1417         return false;
1418       }
1419 
1420       if (P == LLDB_INVALID_ADDRESS) {
1421         if (log)
1422           log->Printf("StoreInst's pointer doesn't resolve to anything");
1423         error.SetErrorToGenericError();
1424         error.SetErrorString(bad_value_error);
1425         return false;
1426       }
1427 
1428       lldb::addr_t R;
1429       lldb_private::Status read_error;
1430       execution_unit.ReadPointerFromMemory(&R, P, read_error);
1431 
1432       if (!read_error.Success()) {
1433         if (log)
1434           log->Printf("Couldn't read the address to be loaded for a LoadInst");
1435         error.SetErrorToGenericError();
1436         error.SetErrorString(memory_read_error);
1437         return false;
1438       }
1439 
1440       size_t target_size = data_layout.getTypeStoreSize(target_ty);
1441       lldb_private::DataBufferHeap buffer(target_size, 0);
1442 
1443       read_error.Clear();
1444       execution_unit.ReadMemory(buffer.GetBytes(), D, buffer.GetByteSize(),
1445                                 read_error);
1446       if (!read_error.Success()) {
1447         if (log)
1448           log->Printf("Couldn't read from a region on behalf of a StoreInst");
1449         error.SetErrorToGenericError();
1450         error.SetErrorString(memory_read_error);
1451         return false;
1452       }
1453 
1454       lldb_private::Status write_error;
1455       execution_unit.WriteMemory(R, buffer.GetBytes(), buffer.GetByteSize(),
1456                                  write_error);
1457       if (!write_error.Success()) {
1458         if (log)
1459           log->Printf("Couldn't write to a region on behalf of a StoreInst");
1460         error.SetErrorToGenericError();
1461         error.SetErrorString(memory_write_error);
1462         return false;
1463       }
1464 
1465       if (log) {
1466         log->Printf("Interpreted a StoreInst");
1467         log->Printf("  D : 0x%" PRIx64, D);
1468         log->Printf("  P : 0x%" PRIx64, P);
1469         log->Printf("  R : 0x%" PRIx64, R);
1470       }
1471     } break;
1472     case Instruction::Call: {
1473       const CallInst *call_inst = dyn_cast<CallInst>(inst);
1474 
1475       if (!call_inst) {
1476         if (log)
1477           log->Printf(
1478               "getOpcode() returns %s, but instruction is not a CallInst",
1479               inst->getOpcodeName());
1480         error.SetErrorToGenericError();
1481         error.SetErrorString(interpreter_internal_error);
1482         return false;
1483       }
1484 
1485       if (CanIgnoreCall(call_inst))
1486         break;
1487 
1488       // Get the return type
1489       llvm::Type *returnType = call_inst->getType();
1490       if (returnType == nullptr) {
1491         error.SetErrorToGenericError();
1492         error.SetErrorString("unable to access return type");
1493         return false;
1494       }
1495 
1496       // Work with void, integer and pointer return types
1497       if (!returnType->isVoidTy() && !returnType->isIntegerTy() &&
1498           !returnType->isPointerTy()) {
1499         error.SetErrorToGenericError();
1500         error.SetErrorString("return type is not supported");
1501         return false;
1502       }
1503 
1504       // Check we can actually get a thread
1505       if (exe_ctx.GetThreadPtr() == nullptr) {
1506         error.SetErrorToGenericError();
1507         error.SetErrorStringWithFormat("unable to acquire thread");
1508         return false;
1509       }
1510 
1511       // Make sure we have a valid process
1512       if (!exe_ctx.GetProcessPtr()) {
1513         error.SetErrorToGenericError();
1514         error.SetErrorStringWithFormat("unable to get the process");
1515         return false;
1516       }
1517 
1518       // Find the address of the callee function
1519       lldb_private::Scalar I;
1520       const llvm::Value *val = call_inst->getCalledValue();
1521 
1522       if (!frame.EvaluateValue(I, val, module)) {
1523         error.SetErrorToGenericError();
1524         error.SetErrorString("unable to get address of function");
1525         return false;
1526       }
1527       lldb_private::Address funcAddr(I.ULongLong(LLDB_INVALID_ADDRESS));
1528 
1529       lldb_private::DiagnosticManager diagnostics;
1530       lldb_private::EvaluateExpressionOptions options;
1531 
1532       // We generally receive a function pointer which we must dereference
1533       llvm::Type *prototype = val->getType();
1534       if (!prototype->isPointerTy()) {
1535         error.SetErrorToGenericError();
1536         error.SetErrorString("call need function pointer");
1537         return false;
1538       }
1539 
1540       // Dereference the function pointer
1541       prototype = prototype->getPointerElementType();
1542       if (!(prototype->isFunctionTy() || prototype->isFunctionVarArg())) {
1543         error.SetErrorToGenericError();
1544         error.SetErrorString("call need function pointer");
1545         return false;
1546       }
1547 
1548       // Find number of arguments
1549       const int numArgs = call_inst->getNumArgOperands();
1550 
1551       // We work with a fixed array of 16 arguments which is our upper limit
1552       static lldb_private::ABI::CallArgument rawArgs[16];
1553       if (numArgs >= 16) {
1554         error.SetErrorToGenericError();
1555         error.SetErrorStringWithFormat("function takes too many arguments");
1556         return false;
1557       }
1558 
1559       // Push all function arguments to the argument list that will be passed
1560       // to the call function thread plan
1561       for (int i = 0; i < numArgs; i++) {
1562         // Get details of this argument
1563         llvm::Value *arg_op = call_inst->getArgOperand(i);
1564         llvm::Type *arg_ty = arg_op->getType();
1565 
1566         // Ensure that this argument is an supported type
1567         if (!arg_ty->isIntegerTy() && !arg_ty->isPointerTy()) {
1568           error.SetErrorToGenericError();
1569           error.SetErrorStringWithFormat("argument %d must be integer type", i);
1570           return false;
1571         }
1572 
1573         // Extract the arguments value
1574         lldb_private::Scalar tmp_op = 0;
1575         if (!frame.EvaluateValue(tmp_op, arg_op, module)) {
1576           error.SetErrorToGenericError();
1577           error.SetErrorStringWithFormat("unable to evaluate argument %d", i);
1578           return false;
1579         }
1580 
1581         // Check if this is a string literal or constant string pointer
1582         if (arg_ty->isPointerTy()) {
1583           // Pointer to just one type
1584           assert(arg_ty->getNumContainedTypes() == 1);
1585 
1586           lldb::addr_t addr = tmp_op.ULongLong();
1587           size_t dataSize = 0;
1588 
1589           bool Success = execution_unit.GetAllocSize(addr, dataSize);
1590           (void)Success;
1591           assert(Success &&
1592                  "unable to locate host data for transfer to device");
1593           // Create the required buffer
1594           rawArgs[i].size = dataSize;
1595           rawArgs[i].data_ap.reset(new uint8_t[dataSize + 1]);
1596 
1597           // Read string from host memory
1598           execution_unit.ReadMemory(rawArgs[i].data_ap.get(), addr, dataSize,
1599                                     error);
1600           assert(!error.Fail() &&
1601                  "we have failed to read the string from memory");
1602 
1603           // Add null terminator
1604           rawArgs[i].data_ap[dataSize] = '\0';
1605           rawArgs[i].type = lldb_private::ABI::CallArgument::HostPointer;
1606         } else /* if ( arg_ty->isPointerTy() ) */
1607         {
1608           rawArgs[i].type = lldb_private::ABI::CallArgument::TargetValue;
1609           // Get argument size in bytes
1610           rawArgs[i].size = arg_ty->getIntegerBitWidth() / 8;
1611           // Push value into argument list for thread plan
1612           rawArgs[i].value = tmp_op.ULongLong();
1613         }
1614       }
1615 
1616       // Pack the arguments into an llvm::array
1617       llvm::ArrayRef<lldb_private::ABI::CallArgument> args(rawArgs, numArgs);
1618 
1619       // Setup a thread plan to call the target function
1620       lldb::ThreadPlanSP call_plan_sp(
1621           new lldb_private::ThreadPlanCallFunctionUsingABI(
1622               exe_ctx.GetThreadRef(), funcAddr, *prototype, *returnType, args,
1623               options));
1624 
1625       // Check if the plan is valid
1626       lldb_private::StreamString ss;
1627       if (!call_plan_sp || !call_plan_sp->ValidatePlan(&ss)) {
1628         error.SetErrorToGenericError();
1629         error.SetErrorStringWithFormat(
1630             "unable to make ThreadPlanCallFunctionUsingABI for 0x%llx",
1631             I.ULongLong());
1632         return false;
1633       }
1634 
1635       exe_ctx.GetProcessPtr()->SetRunningUserExpression(true);
1636 
1637       // Execute the actual function call thread plan
1638       lldb::ExpressionResults res = exe_ctx.GetProcessRef().RunThreadPlan(
1639           exe_ctx, call_plan_sp, options, diagnostics);
1640 
1641       // Check that the thread plan completed successfully
1642       if (res != lldb::ExpressionResults::eExpressionCompleted) {
1643         error.SetErrorToGenericError();
1644         error.SetErrorStringWithFormat("ThreadPlanCallFunctionUsingABI failed");
1645         return false;
1646       }
1647 
1648       exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
1649 
1650       // Void return type
1651       if (returnType->isVoidTy()) {
1652         // Cant assign to void types, so we leave the frame untouched
1653       } else
1654           // Integer or pointer return type
1655           if (returnType->isIntegerTy() || returnType->isPointerTy()) {
1656         // Get the encapsulated return value
1657         lldb::ValueObjectSP retVal = call_plan_sp.get()->GetReturnValueObject();
1658 
1659         lldb_private::Scalar returnVal = -1;
1660         lldb_private::ValueObject *vobj = retVal.get();
1661 
1662         // Check if the return value is valid
1663         if (vobj == nullptr || retVal.empty()) {
1664           error.SetErrorToGenericError();
1665           error.SetErrorStringWithFormat("unable to get the return value");
1666           return false;
1667         }
1668 
1669         // Extract the return value as a integer
1670         lldb_private::Value &value = vobj->GetValue();
1671         returnVal = value.GetScalar();
1672 
1673         // Push the return value as the result
1674         frame.AssignValue(inst, returnVal, module);
1675       }
1676     } break;
1677     }
1678 
1679     ++frame.m_ii;
1680   }
1681 
1682   if (num_insts >= 4096) {
1683     error.SetErrorToGenericError();
1684     error.SetErrorString(infinite_loop_error);
1685     return false;
1686   }
1687 
1688   return false;
1689 }
1690