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llvm-project/lldb/source/Expression/IRInterpreter.cpp

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//===-- IRInterpreter.cpp -------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "lldb/Expression/IRInterpreter.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Expression/DiagnosticManager.h"
#include "lldb/Expression/IRExecutionUnit.h"
#include "lldb/Expression/IRMemoryMap.h"
#include "lldb/Utility/ConstString.h"
#include "lldb/Utility/DataExtractor.h"
#include "lldb/Utility/Endian.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/Scalar.h"
#include "lldb/Utility/Status.h"
#include "lldb/Utility/StreamString.h"
#include "lldb/Target/ABI.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadPlan.h"
#include "lldb/Target/ThreadPlanCallFunctionUsingABI.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.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;
}
static bool CanIgnoreCall(const CallInst *call) {
const llvm::Function *called_function = call->getCalledFunction();
if (!called_function)
return false;
if (called_function->isIntrinsic()) {
switch (called_function->getIntrinsicID()) {
default:
break;
case llvm::Intrinsic::dbg_declare:
case llvm::Intrinsic::dbg_value:
return true;
}
}
return false;
}
class InterpreterStackFrame {
public:
typedef std::map<const Value *, lldb::addr_t> ValueMap;
ValueMap m_values;
DataLayout &m_target_data;
lldb_private::IRExecutionUnit &m_execution_unit;
const BasicBlock *m_bb;
const BasicBlock *m_prev_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::IRExecutionUnit &execution_unit,
lldb::addr_t stack_frame_bottom,
lldb::addr_t stack_frame_top)
: m_target_data(target_data), m_execution_unit(execution_unit),
m_bb(nullptr), m_prev_bb(nullptr) {
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_prev_bb = m_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 std::string(ss.GetString());
}
bool AssignToMatchType(lldb_private::Scalar &scalar, uint64_t u64value,
Type *type) {
size_t type_size = m_target_data.getTypeStoreSize(type);
if (type_size > 8)
return false;
if (type_size != 1)
type_size = PowerOf2Ceil(type_size);
scalar = llvm::APInt(type_size*8, u64value);
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::Status extract_error;
m_execution_unit.GetMemoryData(value_extractor, process_address,
value_size, extract_error);
if (!extract_error.Success())
return false;
lldb::offset_t offset = 0;
if (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.ULongLong(), 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::Status get_data_error;
if (!cast_scalar.GetAsMemoryData(buf.GetBytes(), buf.GetByteSize(),
m_byte_order, get_data_error))
return false;
lldb_private::Status write_error;
m_execution_unit.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::FunctionVal:
if (const Function *constant_func = dyn_cast<Function>(constant)) {
lldb_private::ConstString name(constant_func->getName());
bool missing_weak = false;
lldb::addr_t addr = m_execution_unit.FindSymbol(name, missing_weak);
if (addr == LLDB_INVALID_ADDRESS || missing_weak)
return false;
value = APInt(m_target_data.getPointerSizeInBits(), addr);
return true;
}
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);
Type *src_elem_ty =
cast<GEPOperator>(constant_expr)->getSourceElementType();
uint64_t offset =
m_target_data.getIndexedOffsetInType(src_elem_ty, 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::Status write_error;
m_execution_unit.WritePointerToMemory(data_address, address, write_error);
if (!write_error.Success()) {
lldb_private::Status free_error;
m_execution_unit.Free(data_address, free_error);
return false;
}
m_values[value] = data_address;
lldb_private::Log *log(
lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
if (log) {
LLDB_LOGF(log, "Made an allocation for argument %s",
PrintValue(value).c_str());
LLDB_LOGF(log, " Data region : %llx", (unsigned long long)address);
LLDB_LOGF(log, " 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;
size_t constant_size = m_target_data.getTypeStoreSize(constant->getType());
lldb_private::DataBufferHeap buf(constant_size, 0);
lldb_private::Status get_data_error;
lldb_private::Scalar resolved_scalar(
resolved_value.zextOrTrunc(llvm::NextPowerOf2(constant_size) * 8));
if (!resolved_scalar.GetAsMemoryData(buf.GetBytes(), buf.GetByteSize(),
m_byte_order, get_data_error))
return false;
lldb_private::Status write_error;
m_execution_unit.WriteMemory(process_address, buf.GetBytes(),
buf.GetByteSize(), 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 Malloc(llvm::Type *type) {
lldb_private::Status 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::Status read_error;
m_execution_unit.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 std::string(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::Status free_error;
m_execution_unit.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";
static const char *too_many_functions_error =
"Interpreter doesn't handle modules with multiple function bodies.";
static bool CanResolveConstant(llvm::Constant *constant) {
switch (constant->getValueID()) {
default:
return false;
case Value::ConstantIntVal:
case Value::ConstantFPVal:
case Value::FunctionVal:
return true;
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 CanResolveConstant(constant_expr->getOperand(0));
case Instruction::GetElementPtr: {
ConstantExpr::const_op_iterator op_cursor = constant_expr->op_begin();
Constant *base = dyn_cast<Constant>(*op_cursor);
if (!base)
return false;
return CanResolveConstant(base);
}
}
} else {
return false;
}
case Value::ConstantPointerNullVal:
return true;
}
}
bool IRInterpreter::CanInterpret(llvm::Module &module, llvm::Function &function,
lldb_private::Status &error,
const bool support_function_calls) {
lldb_private::Log *log(
lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
bool saw_function_with_body = false;
for (Function &f : module) {
if (f.begin() != f.end()) {
if (saw_function_with_body) {
LLDB_LOGF(log, "More than one function in the module has a body");
error.SetErrorToGenericError();
error.SetErrorString(too_many_functions_error);
return false;
}
saw_function_with_body = true;
}
}
for (BasicBlock &bb : function) {
for (Instruction &ii : bb) {
switch (ii.getOpcode()) {
default: {
LLDB_LOGF(log, "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::PHI:
break;
case Instruction::Call: {
CallInst *call_inst = dyn_cast<CallInst>(&ii);
if (!call_inst) {
error.SetErrorToGenericError();
error.SetErrorString(interpreter_internal_error);
return false;
}
if (!CanIgnoreCall(call_inst) && !support_function_calls) {
LLDB_LOGF(log, "Unsupported instruction: %s",
PrintValue(&ii).c_str());
error.SetErrorToGenericError();
error.SetErrorString(unsupported_opcode_error);
return false;
}
} break;
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: {
LLDB_LOGF(log, "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::Trunc:
case Instruction::UDiv:
case Instruction::URem:
case Instruction::Xor:
case Instruction::ZExt:
break;
}
for (unsigned 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: {
LLDB_LOGF(log, "Unsupported operand type: %s",
PrintType(operand_type).c_str());
error.SetErrorString(unsupported_operand_error);
return false;
}
}
// The IR interpreter currently doesn't know about
// 128-bit integers. As they're not that frequent,
// we can just fall back to the JIT rather than
// choking.
if (operand_type->getPrimitiveSizeInBits() > 64) {
LLDB_LOGF(log, "Unsupported operand type: %s",
PrintType(operand_type).c_str());
error.SetErrorString(unsupported_operand_error);
return false;
}
if (Constant *constant = llvm::dyn_cast<Constant>(operand)) {
if (!CanResolveConstant(constant)) {
LLDB_LOGF(log, "Unsupported constant: %s",
PrintValue(constant).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::IRExecutionUnit &execution_unit,
lldb_private::Status &error,
lldb::addr_t stack_frame_bottom,
lldb::addr_t stack_frame_top,
lldb_private::ExecutionContext &exe_ctx) {
lldb_private::Log *log(
lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
if (log) {
std::string s;
raw_string_ostream oss(s);
module.print(oss, nullptr);
oss.flush();
LLDB_LOGF(log, "Module as passed in to IRInterpreter::Interpret: \n\"%s\"",
s.c_str());
}
DataLayout data_layout(&module);
InterpreterStackFrame frame(data_layout, execution_unit, 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() <= static_cast<size_t>(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.front());
while (frame.m_ii != frame.m_ie && (++num_insts < 4096)) {
const Instruction *inst = &*frame.m_ii;
LLDB_LOGF(log, "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) {
LLDB_LOGF(
log,
"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)) {
LLDB_LOGF(log, "Couldn't evaluate %s", PrintValue(lhs).c_str());
error.SetErrorToGenericError();
error.SetErrorString(bad_value_error);
return false;
}
if (!frame.EvaluateValue(R, rhs, module)) {
LLDB_LOGF(log, "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:
L.MakeUnsigned();
R.MakeUnsigned();
result = L / R;
break;
case Instruction::SRem:
L.MakeSigned();
R.MakeSigned();
result = L % R;
break;
case Instruction::URem:
L.MakeUnsigned();
R.MakeUnsigned();
result = L % R;
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) {
LLDB_LOGF(log, "Interpreted a %s", inst->getOpcodeName());
LLDB_LOGF(log, " L : %s", frame.SummarizeValue(lhs).c_str());
LLDB_LOGF(log, " R : %s", frame.SummarizeValue(rhs).c_str());
LLDB_LOGF(log, " = : %s", frame.SummarizeValue(inst).c_str());
}
} break;
case Instruction::Alloca: {
const AllocaInst *alloca_inst = cast<AllocaInst>(inst);
if (alloca_inst->isArrayAllocation()) {
LLDB_LOGF(log,
"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) {
LLDB_LOGF(log, "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) {
LLDB_LOGF(log,
"Couldn't allocate the result pointer for an AllocaInst");
error.SetErrorToGenericError();
error.SetErrorString(memory_allocation_error);
return false;
}
lldb_private::Status write_error;
execution_unit.WritePointerToMemory(P, R, write_error);
if (!write_error.Success()) {
LLDB_LOGF(log, "Couldn't write the result pointer for an AllocaInst");
error.SetErrorToGenericError();
error.SetErrorString(memory_write_error);
lldb_private::Status free_error;
execution_unit.Free(P, free_error);
execution_unit.Free(R, free_error);
return false;
}
frame.m_values[alloca_inst] = P;
if (log) {
LLDB_LOGF(log, "Interpreted an AllocaInst");
LLDB_LOGF(log, " R : 0x%" PRIx64, R);
LLDB_LOGF(log, " P : 0x%" PRIx64, P);
}
} break;
case Instruction::BitCast:
case Instruction::ZExt: {
const CastInst *cast_inst = cast<CastInst>(inst);
Value *source = cast_inst->getOperand(0);
lldb_private::Scalar S;
if (!frame.EvaluateValue(S, source, module)) {
LLDB_LOGF(log, "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 = cast<CastInst>(inst);
Value *source = cast_inst->getOperand(0);
lldb_private::Scalar S;
if (!frame.EvaluateValue(S, source, module)) {
LLDB_LOGF(log, "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 = cast<BranchInst>(inst);
if (br_inst->isConditional()) {
Value *condition = br_inst->getCondition();
lldb_private::Scalar C;
if (!frame.EvaluateValue(C, condition, module)) {
LLDB_LOGF(log, "Couldn't evaluate %s", PrintValue(condition).c_str());
error.SetErrorToGenericError();
error.SetErrorString(bad_value_error);
return false;
}
if (!C.IsZero())
frame.Jump(br_inst->getSuccessor(0));
else
frame.Jump(br_inst->getSuccessor(1));
if (log) {
LLDB_LOGF(log, "Interpreted a BrInst with a condition");
LLDB_LOGF(log, " cond : %s",
frame.SummarizeValue(condition).c_str());
}
} else {
frame.Jump(br_inst->getSuccessor(0));
if (log) {
LLDB_LOGF(log, "Interpreted a BrInst with no condition");
}
}
}
continue;
case Instruction::PHI: {
const PHINode *phi_inst = cast<PHINode>(inst);
if (!frame.m_prev_bb) {
LLDB_LOGF(log,
"Encountered PHI node without having jumped from another "
"basic block");
error.SetErrorToGenericError();
error.SetErrorString(interpreter_internal_error);
return false;
}
Value *value = phi_inst->getIncomingValueForBlock(frame.m_prev_bb);
lldb_private::Scalar result;
if (!frame.EvaluateValue(result, value, module)) {
LLDB_LOGF(log, "Couldn't evaluate %s", PrintValue(value).c_str());
error.SetErrorToGenericError();
error.SetErrorString(bad_value_error);
return false;
}
frame.AssignValue(inst, result, module);
if (log) {
LLDB_LOGF(log, "Interpreted a %s", inst->getOpcodeName());
LLDB_LOGF(log, " Incoming value : %s",
frame.SummarizeValue(value).c_str());
}
} break;
case Instruction::GetElementPtr: {
const GetElementPtrInst *gep_inst = cast<GetElementPtrInst>(inst);
const Value *pointer_operand = gep_inst->getPointerOperand();
Type *src_elem_ty = gep_inst->getSourceElementType();
lldb_private::Scalar P;
if (!frame.EvaluateValue(P, pointer_operand, module)) {
LLDB_LOGF(log, "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)) {
LLDB_LOGF(log, "Couldn't evaluate %s", PrintValue(*ii).c_str());
error.SetErrorToGenericError();
error.SetErrorString(bad_value_error);
return false;
}
LLDB_LOGF(log, "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.getIndexedOffsetInType(src_elem_ty, const_indices);
lldb_private::Scalar Poffset = P + offset;
frame.AssignValue(inst, Poffset, module);
if (log) {
LLDB_LOGF(log, "Interpreted a GetElementPtrInst");
LLDB_LOGF(log, " P : %s",
frame.SummarizeValue(pointer_operand).c_str());
LLDB_LOGF(log, " Poffset : %s", frame.SummarizeValue(inst).c_str());
}
} break;
case Instruction::ICmp: {
const ICmpInst *icmp_inst = cast<ICmpInst>(inst);
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)) {
LLDB_LOGF(log, "Couldn't evaluate %s", PrintValue(lhs).c_str());
error.SetErrorToGenericError();
error.SetErrorString(bad_value_error);
return false;
}
if (!frame.EvaluateValue(R, rhs, module)) {
LLDB_LOGF(log, "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:
L.MakeUnsigned();
R.MakeUnsigned();
result = (L > R);
break;
case CmpInst::ICMP_UGE:
L.MakeUnsigned();
R.MakeUnsigned();
result = (L >= R);
break;
case CmpInst::ICMP_ULT:
L.MakeUnsigned();
R.MakeUnsigned();
result = (L < R);
break;
case CmpInst::ICMP_ULE:
L.MakeUnsigned();
R.MakeUnsigned();
result = (L <= R);
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) {
LLDB_LOGF(log, "Interpreted an ICmpInst");
LLDB_LOGF(log, " L : %s", frame.SummarizeValue(lhs).c_str());
LLDB_LOGF(log, " R : %s", frame.SummarizeValue(rhs).c_str());
LLDB_LOGF(log, " = : %s", frame.SummarizeValue(inst).c_str());
}
} break;
case Instruction::IntToPtr: {
const IntToPtrInst *int_to_ptr_inst = cast<IntToPtrInst>(inst);
Value *src_operand = int_to_ptr_inst->getOperand(0);
lldb_private::Scalar I;
if (!frame.EvaluateValue(I, src_operand, module)) {
LLDB_LOGF(log, "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) {
LLDB_LOGF(log, "Interpreted an IntToPtr");
LLDB_LOGF(log, " Src : %s", frame.SummarizeValue(src_operand).c_str());
LLDB_LOGF(log, " = : %s", frame.SummarizeValue(inst).c_str());
}
} break;
case Instruction::PtrToInt: {
const PtrToIntInst *ptr_to_int_inst = cast<PtrToIntInst>(inst);
Value *src_operand = ptr_to_int_inst->getOperand(0);
lldb_private::Scalar I;
if (!frame.EvaluateValue(I, src_operand, module)) {
LLDB_LOGF(log, "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) {
LLDB_LOGF(log, "Interpreted a PtrToInt");
LLDB_LOGF(log, " Src : %s", frame.SummarizeValue(src_operand).c_str());
LLDB_LOGF(log, " = : %s", frame.SummarizeValue(inst).c_str());
}
} break;
case Instruction::Trunc: {
const TruncInst *trunc_inst = cast<TruncInst>(inst);
Value *src_operand = trunc_inst->getOperand(0);
lldb_private::Scalar I;
if (!frame.EvaluateValue(I, src_operand, module)) {
LLDB_LOGF(log, "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) {
LLDB_LOGF(log, "Interpreted a Trunc");
LLDB_LOGF(log, " Src : %s", frame.SummarizeValue(src_operand).c_str());
LLDB_LOGF(log, " = : %s", frame.SummarizeValue(inst).c_str());
}
} break;
case Instruction::Load: {
const LoadInst *load_inst = cast<LoadInst>(inst);
// 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) {
LLDB_LOGF(log, "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) {
LLDB_LOGF(log, "LoadInst's value doesn't resolve to anything");
error.SetErrorToGenericError();
error.SetErrorString(bad_value_error);
return false;
}
if (P == LLDB_INVALID_ADDRESS) {
LLDB_LOGF(log, "LoadInst's pointer doesn't resolve to anything");
error.SetErrorToGenericError();
error.SetErrorString(bad_value_error);
return false;
}
lldb::addr_t R;
lldb_private::Status read_error;
execution_unit.ReadPointerFromMemory(&R, P, read_error);
if (!read_error.Success()) {
LLDB_LOGF(log, "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();
execution_unit.ReadMemory(buffer.GetBytes(), R, buffer.GetByteSize(),
read_error);
if (!read_error.Success()) {
LLDB_LOGF(log, "Couldn't read from a region on behalf of a LoadInst");
error.SetErrorToGenericError();
error.SetErrorString(memory_read_error);
return false;
}
lldb_private::Status write_error;
execution_unit.WriteMemory(D, buffer.GetBytes(), buffer.GetByteSize(),
write_error);
if (!write_error.Success()) {
LLDB_LOGF(log, "Couldn't write to a region on behalf of a LoadInst");
error.SetErrorToGenericError();
error.SetErrorString(memory_read_error);
return false;
}
if (log) {
LLDB_LOGF(log, "Interpreted a LoadInst");
LLDB_LOGF(log, " P : 0x%" PRIx64, P);
LLDB_LOGF(log, " R : 0x%" PRIx64, R);
LLDB_LOGF(log, " D : 0x%" PRIx64, D);
}
} break;
case Instruction::Ret: {
return true;
}
case Instruction::Store: {
const StoreInst *store_inst = cast<StoreInst>(inst);
// 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) {
LLDB_LOGF(log, "StoreInst's value doesn't resolve to anything");
error.SetErrorToGenericError();
error.SetErrorString(bad_value_error);
return false;
}
if (P == LLDB_INVALID_ADDRESS) {
LLDB_LOGF(log, "StoreInst's pointer doesn't resolve to anything");
error.SetErrorToGenericError();
error.SetErrorString(bad_value_error);
return false;
}
lldb::addr_t R;
lldb_private::Status read_error;
execution_unit.ReadPointerFromMemory(&R, P, read_error);
if (!read_error.Success()) {
LLDB_LOGF(log, "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();
execution_unit.ReadMemory(buffer.GetBytes(), D, buffer.GetByteSize(),
read_error);
if (!read_error.Success()) {
LLDB_LOGF(log, "Couldn't read from a region on behalf of a StoreInst");
error.SetErrorToGenericError();
error.SetErrorString(memory_read_error);
return false;
}
lldb_private::Status write_error;
execution_unit.WriteMemory(R, buffer.GetBytes(), buffer.GetByteSize(),
write_error);
if (!write_error.Success()) {
LLDB_LOGF(log, "Couldn't write to a region on behalf of a StoreInst");
error.SetErrorToGenericError();
error.SetErrorString(memory_write_error);
return false;
}
if (log) {
LLDB_LOGF(log, "Interpreted a StoreInst");
LLDB_LOGF(log, " D : 0x%" PRIx64, D);
LLDB_LOGF(log, " P : 0x%" PRIx64, P);
LLDB_LOGF(log, " R : 0x%" PRIx64, R);
}
} break;
case Instruction::Call: {
const CallInst *call_inst = cast<CallInst>(inst);
if (CanIgnoreCall(call_inst))
break;
// Get the return type
llvm::Type *returnType = call_inst->getType();
if (returnType == nullptr) {
error.SetErrorToGenericError();
error.SetErrorString("unable to access return type");
return false;
}
// Work with void, integer and pointer return types
if (!returnType->isVoidTy() && !returnType->isIntegerTy() &&
!returnType->isPointerTy()) {
error.SetErrorToGenericError();
error.SetErrorString("return type is not supported");
return false;
}
// Check we can actually get a thread
if (exe_ctx.GetThreadPtr() == nullptr) {
error.SetErrorToGenericError();
error.SetErrorStringWithFormat("unable to acquire thread");
return false;
}
// Make sure we have a valid process
if (!exe_ctx.GetProcessPtr()) {
error.SetErrorToGenericError();
error.SetErrorStringWithFormat("unable to get the process");
return false;
}
// Find the address of the callee function
lldb_private::Scalar I;
const llvm::Value *val = call_inst->getCalledValue();
if (!frame.EvaluateValue(I, val, module)) {
error.SetErrorToGenericError();
error.SetErrorString("unable to get address of function");
return false;
}
lldb_private::Address funcAddr(I.ULongLong(LLDB_INVALID_ADDRESS));
lldb_private::DiagnosticManager diagnostics;
lldb_private::EvaluateExpressionOptions options;
// We generally receive a function pointer which we must dereference
llvm::Type *prototype = val->getType();
if (!prototype->isPointerTy()) {
error.SetErrorToGenericError();
error.SetErrorString("call need function pointer");
return false;
}
// Dereference the function pointer
prototype = prototype->getPointerElementType();
if (!(prototype->isFunctionTy() || prototype->isFunctionVarArg())) {
error.SetErrorToGenericError();
error.SetErrorString("call need function pointer");
return false;
}
// Find number of arguments
const int numArgs = call_inst->getNumArgOperands();
// We work with a fixed array of 16 arguments which is our upper limit
static lldb_private::ABI::CallArgument rawArgs[16];
if (numArgs >= 16) {
error.SetErrorToGenericError();
error.SetErrorStringWithFormat("function takes too many arguments");
return false;
}
// Push all function arguments to the argument list that will be passed
// to the call function thread plan
for (int i = 0; i < numArgs; i++) {
// Get details of this argument
llvm::Value *arg_op = call_inst->getArgOperand(i);
llvm::Type *arg_ty = arg_op->getType();
// Ensure that this argument is an supported type
if (!arg_ty->isIntegerTy() && !arg_ty->isPointerTy()) {
error.SetErrorToGenericError();
error.SetErrorStringWithFormat("argument %d must be integer type", i);
return false;
}
// Extract the arguments value
lldb_private::Scalar tmp_op = 0;
if (!frame.EvaluateValue(tmp_op, arg_op, module)) {
error.SetErrorToGenericError();
error.SetErrorStringWithFormat("unable to evaluate argument %d", i);
return false;
}
// Check if this is a string literal or constant string pointer
if (arg_ty->isPointerTy()) {
lldb::addr_t addr = tmp_op.ULongLong();
size_t dataSize = 0;
bool Success = execution_unit.GetAllocSize(addr, dataSize);
(void)Success;
assert(Success &&
"unable to locate host data for transfer to device");
// Create the required buffer
rawArgs[i].size = dataSize;
rawArgs[i].data_up.reset(new uint8_t[dataSize + 1]);
// Read string from host memory
execution_unit.ReadMemory(rawArgs[i].data_up.get(), addr, dataSize,
error);
assert(!error.Fail() &&
"we have failed to read the string from memory");
// Add null terminator
rawArgs[i].data_up[dataSize] = '\0';
rawArgs[i].type = lldb_private::ABI::CallArgument::HostPointer;
} else /* if ( arg_ty->isPointerTy() ) */
{
rawArgs[i].type = lldb_private::ABI::CallArgument::TargetValue;
// Get argument size in bytes
rawArgs[i].size = arg_ty->getIntegerBitWidth() / 8;
// Push value into argument list for thread plan
rawArgs[i].value = tmp_op.ULongLong();
}
}
// Pack the arguments into an llvm::array
llvm::ArrayRef<lldb_private::ABI::CallArgument> args(rawArgs, numArgs);
// Setup a thread plan to call the target function
lldb::ThreadPlanSP call_plan_sp(
new lldb_private::ThreadPlanCallFunctionUsingABI(
exe_ctx.GetThreadRef(), funcAddr, *prototype, *returnType, args,
options));
// Check if the plan is valid
lldb_private::StreamString ss;
if (!call_plan_sp || !call_plan_sp->ValidatePlan(&ss)) {
error.SetErrorToGenericError();
error.SetErrorStringWithFormat(
"unable to make ThreadPlanCallFunctionUsingABI for 0x%llx",
I.ULongLong());
return false;
}
exe_ctx.GetProcessPtr()->SetRunningUserExpression(true);
// Execute the actual function call thread plan
lldb::ExpressionResults res = exe_ctx.GetProcessRef().RunThreadPlan(
exe_ctx, call_plan_sp, options, diagnostics);
// Check that the thread plan completed successfully
if (res != lldb::ExpressionResults::eExpressionCompleted) {
error.SetErrorToGenericError();
error.SetErrorStringWithFormat("ThreadPlanCallFunctionUsingABI failed");
return false;
}
exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
// Void return type
if (returnType->isVoidTy()) {
// Cant assign to void types, so we leave the frame untouched
} else
// Integer or pointer return type
if (returnType->isIntegerTy() || returnType->isPointerTy()) {
// Get the encapsulated return value
lldb::ValueObjectSP retVal = call_plan_sp.get()->GetReturnValueObject();
lldb_private::Scalar returnVal = -1;
lldb_private::ValueObject *vobj = retVal.get();
// Check if the return value is valid
if (vobj == nullptr || !retVal) {
error.SetErrorToGenericError();
error.SetErrorStringWithFormat("unable to get the return value");
return false;
}
// Extract the return value as a integer
lldb_private::Value &value = vobj->GetValue();
returnVal = value.GetScalar();
// Push the return value as the result
frame.AssignValue(inst, returnVal, module);
}
} break;
}
++frame.m_ii;
}
if (num_insts >= 4096) {
error.SetErrorToGenericError();
error.SetErrorString(infinite_loop_error);
return false;
}
return false;
}
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