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