Merge lldb r188801 to contrib/llvm/tools/lldb/

1 files changed, 1379 insertions, 0 deletions

diff --git a/contrib/llvm/tools/lldb/source/Expression/IRInterpreter.cpp b/contrib/llvm/tools/lldb/source/Expression/IRInterpreter.cpp
new file mode 100644
index 0000000..dcbf584
--- /dev/null
+++ b/contrib/llvm/tools/lldb/source/Expression/IRInterpreter.cpp
@@ -0,0 +1,1379 @@
+//===-- IRInterpreter.cpp ---------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Core/DataExtractor.h"
+#include "lldb/Core/Error.h"
+#include "lldb/Core/Log.h"
+#include "lldb/Core/Scalar.h"
+#include "lldb/Core/StreamString.h"
+#include "lldb/Expression/IRMemoryMap.h"
+#include "lldb/Expression/IRInterpreter.h"
+
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <map>
+
+using namespace llvm;
+
+static std::string 
+PrintValue(const Value *value, bool truncate = false)
+{
+    std::string s;
+    raw_string_ostream rso(s);
+    value->print(rso);
+    rso.flush();
+    if (truncate)
+        s.resize(s.length() - 1);
+    
+    size_t offset;
+    while ((offset = s.find('\n')) != s.npos)
+        s.erase(offset, 1);
+    while (s[0] == ' ' || s[0] == '\t')
+        s.erase(0, 1);
+        
+    return s;
+}
+
+static std::string
+PrintType(const Type *type, bool truncate = false)
+{
+    std::string s;
+    raw_string_ostream rso(s);
+    type->print(rso);
+    rso.flush();
+    if (truncate)
+        s.resize(s.length() - 1);
+    return s;
+}
+
+class InterpreterStackFrame
+{
+public:
+    typedef std::map <const Value*, lldb::addr_t> ValueMap;
+    
+    ValueMap                                m_values;
+    DataLayout                             &m_target_data;
+    lldb_private::IRMemoryMap              &m_memory_map;
+    const BasicBlock                       *m_bb;
+    BasicBlock::const_iterator              m_ii;
+    BasicBlock::const_iterator              m_ie;
+    
+    lldb::addr_t                            m_frame_process_address;
+    size_t                                  m_frame_size;
+    lldb::addr_t                            m_stack_pointer;
+    
+    lldb::ByteOrder                         m_byte_order;
+    size_t                                  m_addr_byte_size;
+    
+    InterpreterStackFrame (DataLayout &target_data,
+                           lldb_private::IRMemoryMap &memory_map,
+                           lldb::addr_t stack_frame_bottom,
+                           lldb::addr_t stack_frame_top) :
+        m_target_data (target_data),
+        m_memory_map (memory_map)
+    {
+        m_byte_order = (target_data.isLittleEndian() ? lldb::eByteOrderLittle : lldb::eByteOrderBig);
+        m_addr_byte_size = (target_data.getPointerSize(0));
+                        
+        m_frame_process_address = stack_frame_bottom;
+        m_frame_size = stack_frame_top - stack_frame_bottom;
+        m_stack_pointer = stack_frame_top;
+    }
+    
+    ~InterpreterStackFrame ()
+    {
+    }
+    
+    void Jump (const BasicBlock *bb)
+    {
+        m_bb = bb;
+        m_ii = m_bb->begin();
+        m_ie = m_bb->end();
+    }
+    
+    std::string SummarizeValue (const Value *value)
+    {
+        lldb_private::StreamString ss;
+
+        ss.Printf("%s", PrintValue(value).c_str());
+        
+        ValueMap::iterator i = m_values.find(value);
+
+        if (i != m_values.end())
+        {
+            lldb::addr_t addr = i->second;
+            
+            ss.Printf(" 0x%llx", (unsigned long long)addr);
+        }
+        
+        return ss.GetString();
+    }
+    
+    bool AssignToMatchType (lldb_private::Scalar &scalar, uint64_t u64value, Type *type)
+    {
+        size_t type_size = m_target_data.getTypeStoreSize(type);
+
+        switch (type_size)
+        {
+        case 1:
+            scalar = (uint8_t)u64value;
+            break;
+        case 2:
+            scalar = (uint16_t)u64value;
+            break;
+        case 4:
+            scalar = (uint32_t)u64value;
+            break;
+        case 8:
+            scalar = (uint64_t)u64value;
+            break;
+        default:
+            return false;
+        }
+        
+        return true;
+    }
+    
+    bool EvaluateValue (lldb_private::Scalar &scalar, const Value *value, Module &module)
+    {
+        const Constant *constant = dyn_cast<Constant>(value);
+        
+        if (constant)
+        {
+            APInt value_apint;
+            
+            if (!ResolveConstantValue(value_apint, constant))
+                return false;
+            
+            return AssignToMatchType(scalar, value_apint.getLimitedValue(), value->getType());
+        }
+        else
+        {
+            lldb::addr_t process_address = ResolveValue(value, module);
+            size_t value_size = m_target_data.getTypeStoreSize(value->getType());
+        
+            lldb_private::DataExtractor value_extractor;
+            lldb_private::Error extract_error;
+            
+            m_memory_map.GetMemoryData(value_extractor, process_address, value_size, extract_error);
+            
+            if (!extract_error.Success())
+                return false;
+            
+            lldb::offset_t offset = 0;
+            if (value_size == 1 || value_size == 2 || value_size == 4 || value_size == 8)
+            {
+                uint64_t u64value = value_extractor.GetMaxU64(&offset, value_size);
+                return AssignToMatchType(scalar, u64value, value->getType());
+            }
+        }
+        
+        return false;
+    }
+    
+    bool AssignValue (const Value *value, lldb_private::Scalar &scalar, Module &module)
+    {
+        lldb::addr_t process_address = ResolveValue (value, module);
+        
+        if (process_address == LLDB_INVALID_ADDRESS)
+            return false;
+    
+        lldb_private::Scalar cast_scalar;
+        
+        if (!AssignToMatchType(cast_scalar, scalar.GetRawBits64(0), value->getType()))
+            return false;
+                
+        size_t value_byte_size = m_target_data.getTypeStoreSize(value->getType());
+        
+        lldb_private::DataBufferHeap buf(value_byte_size, 0);
+        
+        lldb_private::Error get_data_error;
+        
+        if (!cast_scalar.GetAsMemoryData(buf.GetBytes(), buf.GetByteSize(), m_byte_order, get_data_error))
+            return false;
+        
+        lldb_private::Error write_error;
+        
+        m_memory_map.WriteMemory(process_address, buf.GetBytes(), buf.GetByteSize(), write_error);
+        
+        return write_error.Success();
+    }
+    
+    bool ResolveConstantValue (APInt &value, const Constant *constant)
+    {
+        switch (constant->getValueID())
+        {
+        default:
+            break;
+        case Value::ConstantIntVal:
+            if (const ConstantInt *constant_int = dyn_cast<ConstantInt>(constant))
+            {
+                value = constant_int->getValue();
+                return true;
+            }
+            break;
+        case Value::ConstantFPVal:
+            if (const ConstantFP *constant_fp = dyn_cast<ConstantFP>(constant))
+            {
+                value = constant_fp->getValueAPF().bitcastToAPInt();
+                return true;
+            }
+            break;
+        case Value::ConstantExprVal:
+            if (const ConstantExpr *constant_expr = dyn_cast<ConstantExpr>(constant))
+            {
+                switch (constant_expr->getOpcode())
+                {
+                    default:
+                        return false;
+                    case Instruction::IntToPtr:
+                    case Instruction::PtrToInt:
+                    case Instruction::BitCast:
+                        return ResolveConstantValue(value, constant_expr->getOperand(0));
+                    case Instruction::GetElementPtr:
+                    {
+                        ConstantExpr::const_op_iterator op_cursor = constant_expr->op_begin();
+                        ConstantExpr::const_op_iterator op_end = constant_expr->op_end();
+                        
+                        Constant *base = dyn_cast<Constant>(*op_cursor);
+                        
+                        if (!base)
+                            return false;
+                        
+                        if (!ResolveConstantValue(value, base))
+                            return false;
+                        
+                        op_cursor++;
+                        
+                        if (op_cursor == op_end)
+                            return true; // no offset to apply!
+                        
+                        SmallVector <Value *, 8> indices (op_cursor, op_end);
+                        
+                        uint64_t offset = m_target_data.getIndexedOffset(base->getType(), indices);
+                        
+                        const bool is_signed = true;
+                        value += APInt(value.getBitWidth(), offset, is_signed);
+                        
+                        return true;
+                    }
+                }
+            }
+            break;
+        case Value::ConstantPointerNullVal:
+            if (isa<ConstantPointerNull>(constant))
+            {
+                value = APInt(m_target_data.getPointerSizeInBits(), 0);
+                return true;
+            }
+            break;
+        }
+        return false;
+    }
+    
+    bool MakeArgument(const Argument *value, uint64_t address)
+    {
+        lldb::addr_t data_address = Malloc(value->getType());
+        
+        if (data_address == LLDB_INVALID_ADDRESS)
+            return false;
+        
+        lldb_private::Error write_error;
+        
+        m_memory_map.WritePointerToMemory(data_address, address, write_error);
+        
+        if (!write_error.Success())
+        {
+            lldb_private::Error free_error;
+            m_memory_map.Free(data_address, free_error);
+            return false;
+        }
+        
+        m_values[value] = data_address;
+        
+        lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
+
+        if (log)
+        {
+            log->Printf("Made an allocation for argument %s", PrintValue(value).c_str());
+            log->Printf("  Data region    : %llx", (unsigned long long)address);
+            log->Printf("  Ref region     : %llx", (unsigned long long)data_address);
+        }
+        
+        return true;
+    }
+    
+    bool ResolveConstant (lldb::addr_t process_address, const Constant *constant)
+    {
+        APInt resolved_value;
+        
+        if (!ResolveConstantValue(resolved_value, constant))
+            return false;
+        
+        const uint64_t *raw_data = resolved_value.getRawData();
+            
+        size_t constant_size = m_target_data.getTypeStoreSize(constant->getType());
+        
+        lldb_private::Error write_error;
+        
+        m_memory_map.WriteMemory(process_address, (uint8_t*)raw_data, constant_size, write_error);
+        
+        return write_error.Success();
+    }
+    
+    lldb::addr_t Malloc (size_t size, uint8_t byte_alignment)
+    {
+        lldb::addr_t ret = m_stack_pointer;
+        
+        ret -= size;
+        ret -= (ret % byte_alignment);
+        
+        if (ret < m_frame_process_address)
+            return LLDB_INVALID_ADDRESS;
+        
+        m_stack_pointer = ret;
+        return ret;
+    }
+        
+    lldb::addr_t MallocPointer ()
+    {
+        return Malloc(m_target_data.getPointerSize(), m_target_data.getPointerPrefAlignment());
+    }
+    
+    lldb::addr_t Malloc (llvm::Type *type)
+    {
+        lldb_private::Error alloc_error;
+        
+        return Malloc(m_target_data.getTypeAllocSize(type), m_target_data.getPrefTypeAlignment(type));
+    }
+    
+    std::string PrintData (lldb::addr_t addr, llvm::Type *type)
+    {
+        size_t length = m_target_data.getTypeStoreSize(type);
+        
+        lldb_private::DataBufferHeap buf(length, 0);
+        
+        lldb_private::Error read_error;
+        
+        m_memory_map.ReadMemory(buf.GetBytes(), addr, length, read_error);
+        
+        if (!read_error.Success())
+            return std::string("<couldn't read data>");
+        
+        lldb_private::StreamString ss;
+        
+        for (size_t i = 0; i < length; i++)
+        {
+            if ((!(i & 0xf)) && i)
+                ss.Printf("%02hhx - ", buf.GetBytes()[i]);
+            else
+                ss.Printf("%02hhx ", buf.GetBytes()[i]);
+        }
+        
+        return ss.GetString();
+    }
+    
+    lldb::addr_t ResolveValue (const Value *value, Module &module)
+    {
+        ValueMap::iterator i = m_values.find(value);
+        
+        if (i != m_values.end())
+            return i->second;
+        
+        // Fall back and allocate space [allocation type Alloca]
+        
+        lldb::addr_t data_address = Malloc(value->getType());
+        
+        if (const Constant *constant = dyn_cast<Constant>(value))
+        {
+            if (!ResolveConstant (data_address, constant))
+            {
+                lldb_private::Error free_error;
+                m_memory_map.Free(data_address, free_error);
+                return LLDB_INVALID_ADDRESS;
+            }
+        }
+        
+        m_values[value] = data_address;
+        return data_address;
+    }
+};
+
+static const char *unsupported_opcode_error         = "Interpreter doesn't handle one of the expression's opcodes";
+static const char *unsupported_operand_error        = "Interpreter doesn't handle one of the expression's operands";
+//static const char *interpreter_initialization_error = "Interpreter couldn't be initialized";
+static const char *interpreter_internal_error       = "Interpreter encountered an internal error";
+static const char *bad_value_error                  = "Interpreter couldn't resolve a value during execution";
+static const char *memory_allocation_error          = "Interpreter couldn't allocate memory";
+static const char *memory_write_error               = "Interpreter couldn't write to memory";
+static const char *memory_read_error                = "Interpreter couldn't read from memory";
+static const char *infinite_loop_error              = "Interpreter ran for too many cycles";
+//static const char *bad_result_error                 = "Result of expression is in bad memory";
+
+bool
+IRInterpreter::CanInterpret (llvm::Module &module,
+                             llvm::Function &function,
+                             lldb_private::Error &error)
+{
+    lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
+    
+    bool saw_function_with_body = false;
+    
+    for (Module::iterator fi = module.begin(), fe = module.end();
+         fi != fe;
+         ++fi)
+    {
+        if (fi->begin() != fi->end())
+        {
+            if (saw_function_with_body)
+                return false;
+            saw_function_with_body = true;
+        }
+    }
+    
+    for (Function::iterator bbi = function.begin(), bbe = function.end();
+         bbi != bbe;
+         ++bbi)
+    {
+        for (BasicBlock::iterator ii = bbi->begin(), ie = bbi->end();
+             ii != ie;
+             ++ii)
+        {
+            switch (ii->getOpcode())
+            {
+            default:
+                {
+                    if (log)
+                        log->Printf("Unsupported instruction: %s", PrintValue(ii).c_str());
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(unsupported_opcode_error);
+                    return false;
+                }
+            case Instruction::Add:
+            case Instruction::Alloca:
+            case Instruction::BitCast:
+            case Instruction::Br:
+            case Instruction::GetElementPtr:
+                break;
+            case Instruction::ICmp:
+                {
+                    ICmpInst *icmp_inst = dyn_cast<ICmpInst>(ii);
+                    
+                    if (!icmp_inst)
+                    {
+                        error.SetErrorToGenericError();
+                        error.SetErrorString(interpreter_internal_error);
+                        return false;
+                    }
+                    
+                    switch (icmp_inst->getPredicate())
+                    {
+                    default:
+                    {
+                        if (log)
+                            log->Printf("Unsupported ICmp predicate: %s", PrintValue(ii).c_str());
+                        
+                        error.SetErrorToGenericError();
+                        error.SetErrorString(unsupported_opcode_error);
+                        return false;
+                    }
+                    case CmpInst::ICMP_EQ:
+                    case CmpInst::ICMP_NE:
+                    case CmpInst::ICMP_UGT:
+                    case CmpInst::ICMP_UGE:
+                    case CmpInst::ICMP_ULT:
+                    case CmpInst::ICMP_ULE:
+                    case CmpInst::ICMP_SGT:
+                    case CmpInst::ICMP_SGE:
+                    case CmpInst::ICMP_SLT:
+                    case CmpInst::ICMP_SLE:
+                        break;
+                    }
+                }
+                break;
+            case Instruction::And:
+            case Instruction::AShr:
+            case Instruction::IntToPtr:
+            case Instruction::PtrToInt:
+            case Instruction::Load:
+            case Instruction::LShr:
+            case Instruction::Mul:
+            case Instruction::Or:
+            case Instruction::Ret:
+            case Instruction::SDiv:
+            case Instruction::SExt:
+            case Instruction::Shl:
+            case Instruction::SRem:
+            case Instruction::Store:
+            case Instruction::Sub:
+            case Instruction::UDiv:
+            case Instruction::URem:
+            case Instruction::Xor:
+            case Instruction::ZExt:
+                break;
+            }
+            
+            for (int oi = 0, oe = ii->getNumOperands();
+                 oi != oe;
+                 ++oi)
+            {
+                Value *operand = ii->getOperand(oi);
+                Type *operand_type = operand->getType();
+                
+                switch (operand_type->getTypeID())
+                {
+                default:
+                    break;
+                case Type::VectorTyID:
+                    {
+                        if (log)
+                            log->Printf("Unsupported operand type: %s", PrintType(operand_type).c_str());
+                        error.SetErrorString(unsupported_operand_error);
+                        return false;
+                    }
+                }
+            }
+        }
+        
+    }
+    
+    return true;}
+
+bool
+IRInterpreter::Interpret (llvm::Module &module,
+                          llvm::Function &function,
+                          llvm::ArrayRef<lldb::addr_t> args,
+                          lldb_private::IRMemoryMap &memory_map,
+                          lldb_private::Error &error,
+                          lldb::addr_t stack_frame_bottom,
+                          lldb::addr_t stack_frame_top)
+{
+    lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
+    
+    if (log)
+    {
+        std::string s;
+        raw_string_ostream oss(s);
+        
+        module.print(oss, NULL);
+        
+        oss.flush();
+        
+        log->Printf("Module as passed in to IRInterpreter::Interpret: \n\"%s\"", s.c_str());
+    }
+    
+    DataLayout data_layout(&module);
+    
+    InterpreterStackFrame frame(data_layout, memory_map, stack_frame_bottom, stack_frame_top);
+    
+    if (frame.m_frame_process_address == LLDB_INVALID_ADDRESS)
+    {
+        error.SetErrorString("Couldn't allocate stack frame");
+    }
+    
+    int arg_index = 0;
+    
+    for (llvm::Function::arg_iterator ai = function.arg_begin(), ae = function.arg_end();
+         ai != ae;
+         ++ai, ++arg_index)
+    {
+        if (args.size() < arg_index)
+        {
+            error.SetErrorString ("Not enough arguments passed in to function");
+            return false;
+        }
+        
+        lldb::addr_t ptr = args[arg_index];
+
+        frame.MakeArgument(ai, ptr);
+    }
+    
+    uint32_t num_insts = 0;
+    
+    frame.Jump(function.begin());
+    
+    while (frame.m_ii != frame.m_ie && (++num_insts < 4096))
+    {
+        const Instruction *inst = frame.m_ii;
+        
+        if (log)
+            log->Printf("Interpreting %s", PrintValue(inst).c_str());
+        
+        switch (inst->getOpcode())
+        {
+            default:
+                break;
+            case Instruction::Add:
+            case Instruction::Sub:
+            case Instruction::Mul:
+            case Instruction::SDiv:
+            case Instruction::UDiv:
+            case Instruction::SRem:
+            case Instruction::URem:
+            case Instruction::Shl:
+            case Instruction::LShr:
+            case Instruction::AShr:
+            case Instruction::And:
+            case Instruction::Or:
+            case Instruction::Xor:
+            {
+                const BinaryOperator *bin_op = dyn_cast<BinaryOperator>(inst);
+                
+                if (!bin_op)
+                {
+                    if (log)
+                        log->Printf("getOpcode() returns %s, but instruction is not a BinaryOperator", inst->getOpcodeName());
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(interpreter_internal_error);
+                    return false;
+                }
+                
+                Value *lhs = inst->getOperand(0);
+                Value *rhs = inst->getOperand(1);
+                
+                lldb_private::Scalar L;
+                lldb_private::Scalar R;
+                
+                if (!frame.EvaluateValue(L, lhs, module))
+                {
+                    if (log)
+                        log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(bad_value_error);
+                    return false;
+                }
+                
+                if (!frame.EvaluateValue(R, rhs, module))
+                {
+                    if (log)
+                        log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(bad_value_error);
+                    return false;
+                }
+                
+                lldb_private::Scalar result;
+                
+                switch (inst->getOpcode())
+                {
+                    default:
+                        break;
+                    case Instruction::Add:
+                        result = L + R;
+                        break;
+                    case Instruction::Mul:
+                        result = L * R;
+                        break;
+                    case Instruction::Sub:
+                        result = L - R;
+                        break;
+                    case Instruction::SDiv:
+                        L.MakeSigned();
+                        R.MakeSigned();
+                        result = L / R;
+                        break;
+                    case Instruction::UDiv:
+                        result = L.GetRawBits64(0) / R.GetRawBits64(1);
+                        break;
+                    case Instruction::SRem:
+                        L.MakeSigned();
+                        R.MakeSigned();
+                        result = L % R;
+                        break;
+                    case Instruction::URem:
+                        result = L.GetRawBits64(0) % R.GetRawBits64(1);
+                        break;
+                    case Instruction::Shl:
+                        result = L << R;
+                        break;
+                    case Instruction::AShr:
+                        result = L >> R;
+                        break;
+                    case Instruction::LShr:
+                        result = L;
+                        result.ShiftRightLogical(R);
+                        break;
+                    case Instruction::And:
+                        result = L & R;
+                        break;
+                    case Instruction::Or:
+                        result = L | R;
+                        break;
+                    case Instruction::Xor:
+                        result = L ^ R;
+                        break;
+                }
+                
+                frame.AssignValue(inst, result, module);
+                
+                if (log)
+                {
+                    log->Printf("Interpreted a %s", inst->getOpcodeName());
+                    log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
+                    log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
+                    log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
+                }
+            }
+                break;
+            case Instruction::Alloca:
+            {
+                const AllocaInst *alloca_inst = dyn_cast<AllocaInst>(inst);
+                
+                if (!alloca_inst)
+                {
+                    if (log)
+                        log->Printf("getOpcode() returns Alloca, but instruction is not an AllocaInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(interpreter_internal_error);
+                    return false;
+                }
+                
+                if (alloca_inst->isArrayAllocation())
+                {
+                    if (log)
+                        log->Printf("AllocaInsts are not handled if isArrayAllocation() is true");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(unsupported_opcode_error);
+                    return false;
+                }
+                
+                // The semantics of Alloca are:
+                //   Create a region R of virtual memory of type T, backed by a data buffer
+                //   Create a region P of virtual memory of type T*, backed by a data buffer
+                //   Write the virtual address of R into P
+                
+                Type *T = alloca_inst->getAllocatedType();
+                Type *Tptr = alloca_inst->getType();
+                
+                lldb::addr_t R = frame.Malloc(T);
+                
+                if (R == LLDB_INVALID_ADDRESS)
+                {
+                    if (log)
+                        log->Printf("Couldn't allocate memory for an AllocaInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(memory_allocation_error);
+                    return false;
+                }
+                
+                lldb::addr_t P = frame.Malloc(Tptr);
+                
+                if (P == LLDB_INVALID_ADDRESS)
+                {
+                    if (log)
+                        log->Printf("Couldn't allocate the result pointer for an AllocaInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(memory_allocation_error);
+                    return false;
+                }
+                
+                lldb_private::Error write_error;
+                
+                memory_map.WritePointerToMemory(P, R, write_error);
+                
+                if (!write_error.Success())
+                {
+                    if (log)
+                        log->Printf("Couldn't write the result pointer for an AllocaInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(memory_write_error);
+                    lldb_private::Error free_error;
+                    memory_map.Free(P, free_error);
+                    memory_map.Free(R, free_error);
+                    return false;
+                }
+                
+                frame.m_values[alloca_inst] = P;
+                
+                if (log)
+                {
+                    log->Printf("Interpreted an AllocaInst");
+                    log->Printf("  R : 0x%" PRIx64, R);
+                    log->Printf("  P : 0x%" PRIx64, P);
+                }
+            }
+                break;
+            case Instruction::BitCast:
+            case Instruction::ZExt:
+            {
+                const CastInst *cast_inst = dyn_cast<CastInst>(inst);
+                
+                if (!cast_inst)
+                {
+                    if (log)
+                        log->Printf("getOpcode() returns %s, but instruction is not a BitCastInst", cast_inst->getOpcodeName());
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(interpreter_internal_error);
+                    return false;
+                }
+                
+                Value *source = cast_inst->getOperand(0);
+                
+                lldb_private::Scalar S;
+                
+                if (!frame.EvaluateValue(S, source, module))
+                {
+                    if (log)
+                        log->Printf("Couldn't evaluate %s", PrintValue(source).c_str());
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(bad_value_error);
+                    return false;
+                }
+                
+                frame.AssignValue(inst, S, module);
+            }
+                break;
+            case Instruction::SExt:
+            {
+                const CastInst *cast_inst = dyn_cast<CastInst>(inst);
+                
+                if (!cast_inst)
+                {
+                    if (log)
+                        log->Printf("getOpcode() returns %s, but instruction is not a BitCastInst", cast_inst->getOpcodeName());
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(interpreter_internal_error);
+                    return false;
+                }
+                
+                Value *source = cast_inst->getOperand(0);
+                
+                lldb_private::Scalar S;
+                
+                if (!frame.EvaluateValue(S, source, module))
+                {
+                    if (log)
+                        log->Printf("Couldn't evaluate %s", PrintValue(source).c_str());
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(bad_value_error);
+                    return false;
+                }
+                
+                S.MakeSigned();
+                
+                lldb_private::Scalar S_signextend(S.SLongLong());
+                
+                frame.AssignValue(inst, S_signextend, module);
+            }
+                break;
+            case Instruction::Br:
+            {
+                const BranchInst *br_inst = dyn_cast<BranchInst>(inst);
+                
+                if (!br_inst)
+                {
+                    if (log)
+                        log->Printf("getOpcode() returns Br, but instruction is not a BranchInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(interpreter_internal_error);
+                    return false;
+                }
+                
+                if (br_inst->isConditional())
+                {
+                    Value *condition = br_inst->getCondition();
+                    
+                    lldb_private::Scalar C;
+                    
+                    if (!frame.EvaluateValue(C, condition, module))
+                    {
+                        if (log)
+                            log->Printf("Couldn't evaluate %s", PrintValue(condition).c_str());
+                        error.SetErrorToGenericError();
+                        error.SetErrorString(bad_value_error);
+                        return false;
+                    }
+                    
+                    if (C.GetRawBits64(0))
+                        frame.Jump(br_inst->getSuccessor(0));
+                    else
+                        frame.Jump(br_inst->getSuccessor(1));
+                    
+                    if (log)
+                    {
+                        log->Printf("Interpreted a BrInst with a condition");
+                        log->Printf("  cond : %s", frame.SummarizeValue(condition).c_str());
+                    }
+                }
+                else
+                {
+                    frame.Jump(br_inst->getSuccessor(0));
+                    
+                    if (log)
+                    {
+                        log->Printf("Interpreted a BrInst with no condition");
+                    }
+                }
+            }
+                continue;
+            case Instruction::GetElementPtr:
+            {
+                const GetElementPtrInst *gep_inst = dyn_cast<GetElementPtrInst>(inst);
+                
+                if (!gep_inst)
+                {
+                    if (log)
+                        log->Printf("getOpcode() returns GetElementPtr, but instruction is not a GetElementPtrInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(interpreter_internal_error);
+                    return false;
+                }
+                
+                const Value *pointer_operand = gep_inst->getPointerOperand();
+                Type *pointer_type = pointer_operand->getType();
+                
+                lldb_private::Scalar P;
+                
+                if (!frame.EvaluateValue(P, pointer_operand, module))
+                {
+                    if (log)
+                        log->Printf("Couldn't evaluate %s", PrintValue(pointer_operand).c_str());
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(bad_value_error);
+                    return false;
+                }
+                
+                typedef SmallVector <Value *, 8> IndexVector;
+                typedef IndexVector::iterator IndexIterator;
+                
+                SmallVector <Value *, 8> indices (gep_inst->idx_begin(),
+                                                  gep_inst->idx_end());
+                
+                SmallVector <Value *, 8> const_indices;
+                
+                for (IndexIterator ii = indices.begin(), ie = indices.end();
+                     ii != ie;
+                     ++ii)
+                {
+                    ConstantInt *constant_index = dyn_cast<ConstantInt>(*ii);
+                    
+                    if (!constant_index)
+                    {
+                        lldb_private::Scalar I;
+                        
+                        if (!frame.EvaluateValue(I, *ii, module))
+                        {
+                            if (log)
+                                log->Printf("Couldn't evaluate %s", PrintValue(*ii).c_str());
+                            error.SetErrorToGenericError();
+                            error.SetErrorString(bad_value_error);
+                            return false;
+                        }
+                        
+                        if (log)
+                            log->Printf("Evaluated constant index %s as %llu", PrintValue(*ii).c_str(), I.ULongLong(LLDB_INVALID_ADDRESS));
+                        
+                        constant_index = cast<ConstantInt>(ConstantInt::get((*ii)->getType(), I.ULongLong(LLDB_INVALID_ADDRESS)));
+                    }
+                    
+                    const_indices.push_back(constant_index);
+                }
+                
+                uint64_t offset = data_layout.getIndexedOffset(pointer_type, const_indices);
+                
+                lldb_private::Scalar Poffset = P + offset;
+                
+                frame.AssignValue(inst, Poffset, module);
+                
+                if (log)
+                {
+                    log->Printf("Interpreted a GetElementPtrInst");
+                    log->Printf("  P       : %s", frame.SummarizeValue(pointer_operand).c_str());
+                    log->Printf("  Poffset : %s", frame.SummarizeValue(inst).c_str());
+                }
+            }
+                break;
+            case Instruction::ICmp:
+            {
+                const ICmpInst *icmp_inst = dyn_cast<ICmpInst>(inst);
+                
+                if (!icmp_inst)
+                {
+                    if (log)
+                        log->Printf("getOpcode() returns ICmp, but instruction is not an ICmpInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(interpreter_internal_error);
+                    return false;
+                }
+                
+                CmpInst::Predicate predicate = icmp_inst->getPredicate();
+                
+                Value *lhs = inst->getOperand(0);
+                Value *rhs = inst->getOperand(1);
+                
+                lldb_private::Scalar L;
+                lldb_private::Scalar R;
+                
+                if (!frame.EvaluateValue(L, lhs, module))
+                {
+                    if (log)
+                        log->Printf("Couldn't evaluate %s", PrintValue(lhs).c_str());
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(bad_value_error);
+                    return false;
+                }
+                
+                if (!frame.EvaluateValue(R, rhs, module))
+                {
+                    if (log)
+                        log->Printf("Couldn't evaluate %s", PrintValue(rhs).c_str());
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(bad_value_error);
+                    return false;
+                }
+                
+                lldb_private::Scalar result;
+                
+                switch (predicate)
+                {
+                    default:
+                        return false;
+                    case CmpInst::ICMP_EQ:
+                        result = (L == R);
+                        break;
+                    case CmpInst::ICMP_NE:
+                        result = (L != R);
+                        break;
+                    case CmpInst::ICMP_UGT:
+                        result = (L.GetRawBits64(0) > R.GetRawBits64(0));
+                        break;
+                    case CmpInst::ICMP_UGE:
+                        result = (L.GetRawBits64(0) >= R.GetRawBits64(0));
+                        break;
+                    case CmpInst::ICMP_ULT:
+                        result = (L.GetRawBits64(0) < R.GetRawBits64(0));
+                        break;
+                    case CmpInst::ICMP_ULE:
+                        result = (L.GetRawBits64(0) <= R.GetRawBits64(0));
+                        break;
+                    case CmpInst::ICMP_SGT:
+                        L.MakeSigned();
+                        R.MakeSigned();
+                        result = (L > R);
+                        break;
+                    case CmpInst::ICMP_SGE:
+                        L.MakeSigned();
+                        R.MakeSigned();
+                        result = (L >= R);
+                        break;
+                    case CmpInst::ICMP_SLT:
+                        L.MakeSigned();
+                        R.MakeSigned();
+                        result = (L < R);
+                        break;
+                    case CmpInst::ICMP_SLE:
+                        L.MakeSigned();
+                        R.MakeSigned();
+                        result = (L <= R);
+                        break;
+                }
+                
+                frame.AssignValue(inst, result, module);
+                
+                if (log)
+                {
+                    log->Printf("Interpreted an ICmpInst");
+                    log->Printf("  L : %s", frame.SummarizeValue(lhs).c_str());
+                    log->Printf("  R : %s", frame.SummarizeValue(rhs).c_str());
+                    log->Printf("  = : %s", frame.SummarizeValue(inst).c_str());
+                }
+            }
+                break;
+            case Instruction::IntToPtr:
+            {
+                const IntToPtrInst *int_to_ptr_inst = dyn_cast<IntToPtrInst>(inst);
+                
+                if (!int_to_ptr_inst)
+                {
+                    if (log)
+                        log->Printf("getOpcode() returns IntToPtr, but instruction is not an IntToPtrInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(interpreter_internal_error);
+                    return false;
+                }
+                
+                Value *src_operand = int_to_ptr_inst->getOperand(0);
+                
+                lldb_private::Scalar I;
+                
+                if (!frame.EvaluateValue(I, src_operand, module))
+                {
+                    if (log)
+                        log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(bad_value_error);
+                    return false;
+                }
+                
+                frame.AssignValue(inst, I, module);
+                
+                if (log)
+                {
+                    log->Printf("Interpreted an IntToPtr");
+                    log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
+                    log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
+                }
+            }
+                break;
+            case Instruction::PtrToInt:
+            {
+                const PtrToIntInst *ptr_to_int_inst = dyn_cast<PtrToIntInst>(inst);
+                
+                if (!ptr_to_int_inst)
+                {
+                    if (log)
+                        log->Printf("getOpcode() returns PtrToInt, but instruction is not an PtrToIntInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(interpreter_internal_error);
+                    return false;
+                }
+                
+                Value *src_operand = ptr_to_int_inst->getOperand(0);
+                
+                lldb_private::Scalar I;
+                
+                if (!frame.EvaluateValue(I, src_operand, module))
+                {
+                    if (log)
+                        log->Printf("Couldn't evaluate %s", PrintValue(src_operand).c_str());
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(bad_value_error);
+                    return false;
+                }
+                
+                frame.AssignValue(inst, I, module);
+                
+                if (log)
+                {
+                    log->Printf("Interpreted a PtrToInt");
+                    log->Printf("  Src : %s", frame.SummarizeValue(src_operand).c_str());
+                    log->Printf("  =   : %s", frame.SummarizeValue(inst).c_str());
+                }
+            }
+                break;
+            case Instruction::Load:
+            {
+                const LoadInst *load_inst = dyn_cast<LoadInst>(inst);
+                
+                if (!load_inst)
+                {
+                    if (log)
+                        log->Printf("getOpcode() returns Load, but instruction is not a LoadInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(interpreter_internal_error);
+                    return false;
+                }
+                
+                // The semantics of Load are:
+                //   Create a region D that will contain the loaded data
+                //   Resolve the region P containing a pointer
+                //   Dereference P to get the region R that the data should be loaded from
+                //   Transfer a unit of type type(D) from R to D
+                
+                const Value *pointer_operand = load_inst->getPointerOperand();
+                
+                Type *pointer_ty = pointer_operand->getType();
+                PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
+                if (!pointer_ptr_ty)
+                {
+                    if (log)
+                        log->Printf("getPointerOperand()->getType() is not a PointerType");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(interpreter_internal_error);
+                    return false;
+                }
+                Type *target_ty = pointer_ptr_ty->getElementType();
+                
+                lldb::addr_t D = frame.ResolveValue(load_inst, module);
+                lldb::addr_t P = frame.ResolveValue(pointer_operand, module);
+                
+                if (D == LLDB_INVALID_ADDRESS)
+                {
+                    if (log)
+                        log->Printf("LoadInst's value doesn't resolve to anything");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(bad_value_error);
+                    return false;
+                }
+                
+                if (P == LLDB_INVALID_ADDRESS)
+                {
+                    if (log)
+                        log->Printf("LoadInst's pointer doesn't resolve to anything");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(bad_value_error);
+                    return false;
+                }
+                
+                lldb::addr_t R;
+                lldb_private::Error read_error;
+                memory_map.ReadPointerFromMemory(&R, P, read_error);
+                
+                if (!read_error.Success())
+                {
+                    if (log)
+                        log->Printf("Couldn't read the address to be loaded for a LoadInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(memory_read_error);
+                    return false;
+                }
+                
+                size_t target_size = data_layout.getTypeStoreSize(target_ty);
+                lldb_private::DataBufferHeap buffer(target_size, 0);
+                
+                read_error.Clear();
+                memory_map.ReadMemory(buffer.GetBytes(), R, buffer.GetByteSize(), read_error);
+                if (!read_error.Success())
+                {
+                    if (log)
+                        log->Printf("Couldn't read from a region on behalf of a LoadInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(memory_read_error);
+                    return false;
+                }
+                
+                lldb_private::Error write_error;
+                memory_map.WriteMemory(D, buffer.GetBytes(), buffer.GetByteSize(), write_error);
+                if (!write_error.Success())
+                {
+                    if (log)
+                        log->Printf("Couldn't write to a region on behalf of a LoadInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(memory_read_error);
+                    return false;
+                }
+                
+                if (log)
+                {
+                    log->Printf("Interpreted a LoadInst");
+                    log->Printf("  P : 0x%" PRIx64, P);
+                    log->Printf("  R : 0x%" PRIx64, R);
+                    log->Printf("  D : 0x%" PRIx64, D);
+                }
+            }
+                break;
+            case Instruction::Ret:
+            {
+                return true;
+            }
+            case Instruction::Store:
+            {
+                const StoreInst *store_inst = dyn_cast<StoreInst>(inst);
+                
+                if (!store_inst)
+                {
+                    if (log)
+                        log->Printf("getOpcode() returns Store, but instruction is not a StoreInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(interpreter_internal_error);
+                    return false;
+                }
+                
+                // The semantics of Store are:
+                //   Resolve the region D containing the data to be stored
+                //   Resolve the region P containing a pointer
+                //   Dereference P to get the region R that the data should be stored in
+                //   Transfer a unit of type type(D) from D to R
+                
+                const Value *value_operand = store_inst->getValueOperand();
+                const Value *pointer_operand = store_inst->getPointerOperand();
+                
+                Type *pointer_ty = pointer_operand->getType();
+                PointerType *pointer_ptr_ty = dyn_cast<PointerType>(pointer_ty);
+                if (!pointer_ptr_ty)
+                    return false;
+                Type *target_ty = pointer_ptr_ty->getElementType();
+                
+                lldb::addr_t D = frame.ResolveValue(value_operand, module);
+                lldb::addr_t P = frame.ResolveValue(pointer_operand, module);
+                
+                if (D == LLDB_INVALID_ADDRESS)
+                {
+                    if (log)
+                        log->Printf("StoreInst's value doesn't resolve to anything");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(bad_value_error);
+                    return false;
+                }
+                
+                if (P == LLDB_INVALID_ADDRESS)
+                {
+                    if (log)
+                        log->Printf("StoreInst's pointer doesn't resolve to anything");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(bad_value_error);
+                    return false;
+                }
+                
+                lldb::addr_t R;
+                lldb_private::Error read_error;
+                memory_map.ReadPointerFromMemory(&R, P, read_error);
+                
+                if (!read_error.Success())
+                {
+                    if (log)
+                        log->Printf("Couldn't read the address to be loaded for a LoadInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(memory_read_error);
+                    return false;
+                }
+                
+                size_t target_size = data_layout.getTypeStoreSize(target_ty);
+                lldb_private::DataBufferHeap buffer(target_size, 0);
+                
+                read_error.Clear();
+                memory_map.ReadMemory(buffer.GetBytes(), D, buffer.GetByteSize(), read_error);
+                if (!read_error.Success())
+                {
+                    if (log)
+                        log->Printf("Couldn't read from a region on behalf of a StoreInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(memory_read_error);
+                    return false;
+                }
+                
+                lldb_private::Error write_error;
+                memory_map.WriteMemory(R, buffer.GetBytes(), buffer.GetByteSize(), write_error);
+                if (!write_error.Success())
+                {
+                    if (log)
+                        log->Printf("Couldn't write to a region on behalf of a StoreInst");
+                    error.SetErrorToGenericError();
+                    error.SetErrorString(memory_write_error);
+                    return false;
+                }
+                
+                if (log)
+                {
+                    log->Printf("Interpreted a StoreInst");
+                    log->Printf("  D : 0x%" PRIx64, D);
+                    log->Printf("  P : 0x%" PRIx64, P);
+                    log->Printf("  R : 0x%" PRIx64, R);
+                }
+            }
+                break;
+        }
+        
+        ++frame.m_ii;
+    }
+    
+    if (num_insts >= 4096)
+    {
+        error.SetErrorToGenericError();
+        error.SetErrorString(infinite_loop_error);
+        return false;
+    }
+    
+    return false;
+}