in lldb/source/Expression/DWARFExpression.cpp [944:2664]
bool DWARFExpression::Evaluate(
ExecutionContext *exe_ctx, RegisterContext *reg_ctx,
lldb::ModuleSP module_sp, const DataExtractor &opcodes,
const DWARFUnit *dwarf_cu, const lldb::RegisterKind reg_kind,
const Value *initial_value_ptr, const Value *object_address_ptr,
Value &result, Status *error_ptr) {
if (opcodes.GetByteSize() == 0) {
if (error_ptr)
error_ptr->SetErrorString(
"no location, value may have been optimized out");
return false;
}
std::vector<Value> stack;
Process *process = nullptr;
StackFrame *frame = nullptr;
if (exe_ctx) {
process = exe_ctx->GetProcessPtr();
frame = exe_ctx->GetFramePtr();
}
if (reg_ctx == nullptr && frame)
reg_ctx = frame->GetRegisterContext().get();
if (initial_value_ptr)
stack.push_back(*initial_value_ptr);
lldb::offset_t offset = 0;
Value tmp;
uint32_t reg_num;
/// Insertion point for evaluating multi-piece expression.
uint64_t op_piece_offset = 0;
Value pieces; // Used for DW_OP_piece
Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
// A generic type is "an integral type that has the size of an address and an
// unspecified signedness". For now, just use the signedness of the operand.
// TODO: Implement a real typed stack, and store the genericness of the value
// there.
auto to_generic = [&](auto v) {
bool is_signed = std::is_signed<decltype(v)>::value;
return Scalar(llvm::APSInt(
llvm::APInt(8 * opcodes.GetAddressByteSize(), v, is_signed),
!is_signed));
};
// The default kind is a memory location. This is updated by any
// operation that changes this, such as DW_OP_stack_value, and reset
// by composition operations like DW_OP_piece.
LocationDescriptionKind dwarf4_location_description_kind = Memory;
while (opcodes.ValidOffset(offset)) {
const lldb::offset_t op_offset = offset;
const uint8_t op = opcodes.GetU8(&offset);
if (log && log->GetVerbose()) {
size_t count = stack.size();
LLDB_LOGF(log, "Stack before operation has %" PRIu64 " values:",
(uint64_t)count);
for (size_t i = 0; i < count; ++i) {
StreamString new_value;
new_value.Printf("[%" PRIu64 "]", (uint64_t)i);
stack[i].Dump(&new_value);
LLDB_LOGF(log, " %s", new_value.GetData());
}
LLDB_LOGF(log, "0x%8.8" PRIx64 ": %s", op_offset,
DW_OP_value_to_name(op));
}
switch (op) {
// The DW_OP_addr operation has a single operand that encodes a machine
// address and whose size is the size of an address on the target machine.
case DW_OP_addr:
stack.push_back(Scalar(opcodes.GetAddress(&offset)));
stack.back().SetValueType(Value::ValueType::FileAddress);
// Convert the file address to a load address, so subsequent
// DWARF operators can operate on it.
if (frame)
stack.back().ConvertToLoadAddress(module_sp.get(),
frame->CalculateTarget().get());
break;
// The DW_OP_addr_sect_offset4 is used for any location expressions in
// shared libraries that have a location like:
// DW_OP_addr(0x1000)
// If this address resides in a shared library, then this virtual address
// won't make sense when it is evaluated in the context of a running
// process where shared libraries have been slid. To account for this, this
// new address type where we can store the section pointer and a 4 byte
// offset.
// case DW_OP_addr_sect_offset4:
// {
// result_type = eResultTypeFileAddress;
// lldb::Section *sect = (lldb::Section
// *)opcodes.GetMaxU64(&offset, sizeof(void *));
// lldb::addr_t sect_offset = opcodes.GetU32(&offset);
//
// Address so_addr (sect, sect_offset);
// lldb::addr_t load_addr = so_addr.GetLoadAddress();
// if (load_addr != LLDB_INVALID_ADDRESS)
// {
// // We successfully resolve a file address to a load
// // address.
// stack.push_back(load_addr);
// break;
// }
// else
// {
// // We were able
// if (error_ptr)
// error_ptr->SetErrorStringWithFormat ("Section %s in
// %s is not currently loaded.\n",
// sect->GetName().AsCString(),
// sect->GetModule()->GetFileSpec().GetFilename().AsCString());
// return false;
// }
// }
// break;
// OPCODE: DW_OP_deref
// OPERANDS: none
// DESCRIPTION: Pops the top stack entry and treats it as an address.
// The value retrieved from that address is pushed. The size of the data
// retrieved from the dereferenced address is the size of an address on the
// target machine.
case DW_OP_deref: {
if (stack.empty()) {
if (error_ptr)
error_ptr->SetErrorString("Expression stack empty for DW_OP_deref.");
return false;
}
Value::ValueType value_type = stack.back().GetValueType();
switch (value_type) {
case Value::ValueType::HostAddress: {
void *src = (void *)stack.back().GetScalar().ULongLong();
intptr_t ptr;
::memcpy(&ptr, src, sizeof(void *));
stack.back().GetScalar() = ptr;
stack.back().ClearContext();
} break;
case Value::ValueType::FileAddress: {
auto file_addr = stack.back().GetScalar().ULongLong(
LLDB_INVALID_ADDRESS);
if (!module_sp) {
if (error_ptr)
error_ptr->SetErrorString(
"need module to resolve file address for DW_OP_deref");
return false;
}
Address so_addr;
if (!module_sp->ResolveFileAddress(file_addr, so_addr)) {
if (error_ptr)
error_ptr->SetErrorString(
"failed to resolve file address in module");
return false;
}
addr_t load_Addr = so_addr.GetLoadAddress(exe_ctx->GetTargetPtr());
if (load_Addr == LLDB_INVALID_ADDRESS) {
if (error_ptr)
error_ptr->SetErrorString("failed to resolve load address");
return false;
}
stack.back().GetScalar() = load_Addr;
// Fall through to load address promotion code below.
} LLVM_FALLTHROUGH;
case Value::ValueType::Scalar:
// Promote Scalar to LoadAddress and fall through.
stack.back().SetValueType(Value::ValueType::LoadAddress);
LLVM_FALLTHROUGH;
case Value::ValueType::LoadAddress:
if (exe_ctx) {
if (process) {
lldb::addr_t pointer_addr =
stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
Status error;
lldb::addr_t pointer_value =
process->ReadPointerFromMemory(pointer_addr, error);
if (pointer_value != LLDB_INVALID_ADDRESS) {
if (ABISP abi_sp = process->GetABI())
pointer_value = abi_sp->FixCodeAddress(pointer_value);
stack.back().GetScalar() = pointer_value;
stack.back().ClearContext();
} else {
if (error_ptr)
error_ptr->SetErrorStringWithFormat(
"Failed to dereference pointer from 0x%" PRIx64
" for DW_OP_deref: %s\n",
pointer_addr, error.AsCString());
return false;
}
} else {
if (error_ptr)
error_ptr->SetErrorString("NULL process for DW_OP_deref.\n");
return false;
}
} else {
if (error_ptr)
error_ptr->SetErrorString(
"NULL execution context for DW_OP_deref.\n");
return false;
}
break;
case Value::ValueType::Invalid:
if (error_ptr)
error_ptr->SetErrorString("Invalid value type for DW_OP_deref.\n");
return false;
}
} break;
// OPCODE: DW_OP_deref_size
// OPERANDS: 1
// 1 - uint8_t that specifies the size of the data to dereference.
// DESCRIPTION: Behaves like the DW_OP_deref operation: it pops the top
// stack entry and treats it as an address. The value retrieved from that
// address is pushed. In the DW_OP_deref_size operation, however, the size
// in bytes of the data retrieved from the dereferenced address is
// specified by the single operand. This operand is a 1-byte unsigned
// integral constant whose value may not be larger than the size of an
// address on the target machine. The data retrieved is zero extended to
// the size of an address on the target machine before being pushed on the
// expression stack.
case DW_OP_deref_size: {
if (stack.empty()) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack empty for DW_OP_deref_size.");
return false;
}
uint8_t size = opcodes.GetU8(&offset);
Value::ValueType value_type = stack.back().GetValueType();
switch (value_type) {
case Value::ValueType::HostAddress: {
void *src = (void *)stack.back().GetScalar().ULongLong();
intptr_t ptr;
::memcpy(&ptr, src, sizeof(void *));
// I can't decide whether the size operand should apply to the bytes in
// their
// lldb-host endianness or the target endianness.. I doubt this'll ever
// come up but I'll opt for assuming big endian regardless.
switch (size) {
case 1:
ptr = ptr & 0xff;
break;
case 2:
ptr = ptr & 0xffff;
break;
case 3:
ptr = ptr & 0xffffff;
break;
case 4:
ptr = ptr & 0xffffffff;
break;
// the casts are added to work around the case where intptr_t is a 32
// bit quantity;
// presumably we won't hit the 5..7 cases if (void*) is 32-bits in this
// program.
case 5:
ptr = (intptr_t)ptr & 0xffffffffffULL;
break;
case 6:
ptr = (intptr_t)ptr & 0xffffffffffffULL;
break;
case 7:
ptr = (intptr_t)ptr & 0xffffffffffffffULL;
break;
default:
break;
}
stack.back().GetScalar() = ptr;
stack.back().ClearContext();
} break;
case Value::ValueType::Scalar:
case Value::ValueType::LoadAddress:
if (exe_ctx) {
if (process) {
lldb::addr_t pointer_addr =
stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
uint8_t addr_bytes[sizeof(lldb::addr_t)];
Status error;
if (process->ReadMemory(pointer_addr, &addr_bytes, size, error) ==
size) {
DataExtractor addr_data(addr_bytes, sizeof(addr_bytes),
process->GetByteOrder(), size);
lldb::offset_t addr_data_offset = 0;
switch (size) {
case 1:
stack.back().GetScalar() = addr_data.GetU8(&addr_data_offset);
break;
case 2:
stack.back().GetScalar() = addr_data.GetU16(&addr_data_offset);
break;
case 4:
stack.back().GetScalar() = addr_data.GetU32(&addr_data_offset);
break;
case 8:
stack.back().GetScalar() = addr_data.GetU64(&addr_data_offset);
break;
default:
stack.back().GetScalar() =
addr_data.GetAddress(&addr_data_offset);
}
stack.back().ClearContext();
} else {
if (error_ptr)
error_ptr->SetErrorStringWithFormat(
"Failed to dereference pointer from 0x%" PRIx64
" for DW_OP_deref: %s\n",
pointer_addr, error.AsCString());
return false;
}
} else {
if (error_ptr)
error_ptr->SetErrorString("NULL process for DW_OP_deref_size.\n");
return false;
}
} else {
if (error_ptr)
error_ptr->SetErrorString(
"NULL execution context for DW_OP_deref_size.\n");
return false;
}
break;
case Value::ValueType::FileAddress:
case Value::ValueType::Invalid:
if (error_ptr)
error_ptr->SetErrorString("Invalid value for DW_OP_deref_size.\n");
return false;
}
} break;
// OPCODE: DW_OP_xderef_size
// OPERANDS: 1
// 1 - uint8_t that specifies the size of the data to dereference.
// DESCRIPTION: Behaves like the DW_OP_xderef operation: the entry at
// the top of the stack is treated as an address. The second stack entry is
// treated as an "address space identifier" for those architectures that
// support multiple address spaces. The top two stack elements are popped,
// a data item is retrieved through an implementation-defined address
// calculation and pushed as the new stack top. In the DW_OP_xderef_size
// operation, however, the size in bytes of the data retrieved from the
// dereferenced address is specified by the single operand. This operand is
// a 1-byte unsigned integral constant whose value may not be larger than
// the size of an address on the target machine. The data retrieved is zero
// extended to the size of an address on the target machine before being
// pushed on the expression stack.
case DW_OP_xderef_size:
if (error_ptr)
error_ptr->SetErrorString("Unimplemented opcode: DW_OP_xderef_size.");
return false;
// OPCODE: DW_OP_xderef
// OPERANDS: none
// DESCRIPTION: Provides an extended dereference mechanism. The entry at
// the top of the stack is treated as an address. The second stack entry is
// treated as an "address space identifier" for those architectures that
// support multiple address spaces. The top two stack elements are popped,
// a data item is retrieved through an implementation-defined address
// calculation and pushed as the new stack top. The size of the data
// retrieved from the dereferenced address is the size of an address on the
// target machine.
case DW_OP_xderef:
if (error_ptr)
error_ptr->SetErrorString("Unimplemented opcode: DW_OP_xderef.");
return false;
// All DW_OP_constXXX opcodes have a single operand as noted below:
//
// Opcode Operand 1
// DW_OP_const1u 1-byte unsigned integer constant
// DW_OP_const1s 1-byte signed integer constant
// DW_OP_const2u 2-byte unsigned integer constant
// DW_OP_const2s 2-byte signed integer constant
// DW_OP_const4u 4-byte unsigned integer constant
// DW_OP_const4s 4-byte signed integer constant
// DW_OP_const8u 8-byte unsigned integer constant
// DW_OP_const8s 8-byte signed integer constant
// DW_OP_constu unsigned LEB128 integer constant
// DW_OP_consts signed LEB128 integer constant
case DW_OP_const1u:
stack.push_back(to_generic(opcodes.GetU8(&offset)));
break;
case DW_OP_const1s:
stack.push_back(to_generic((int8_t)opcodes.GetU8(&offset)));
break;
case DW_OP_const2u:
stack.push_back(to_generic(opcodes.GetU16(&offset)));
break;
case DW_OP_const2s:
stack.push_back(to_generic((int16_t)opcodes.GetU16(&offset)));
break;
case DW_OP_const4u:
stack.push_back(to_generic(opcodes.GetU32(&offset)));
break;
case DW_OP_const4s:
stack.push_back(to_generic((int32_t)opcodes.GetU32(&offset)));
break;
case DW_OP_const8u:
stack.push_back(to_generic(opcodes.GetU64(&offset)));
break;
case DW_OP_const8s:
stack.push_back(to_generic((int64_t)opcodes.GetU64(&offset)));
break;
// These should also use to_generic, but we can't do that due to a
// producer-side bug in llvm. See llvm.org/pr48087.
case DW_OP_constu:
stack.push_back(Scalar(opcodes.GetULEB128(&offset)));
break;
case DW_OP_consts:
stack.push_back(Scalar(opcodes.GetSLEB128(&offset)));
break;
// OPCODE: DW_OP_dup
// OPERANDS: none
// DESCRIPTION: duplicates the value at the top of the stack
case DW_OP_dup:
if (stack.empty()) {
if (error_ptr)
error_ptr->SetErrorString("Expression stack empty for DW_OP_dup.");
return false;
} else
stack.push_back(stack.back());
break;
// OPCODE: DW_OP_drop
// OPERANDS: none
// DESCRIPTION: pops the value at the top of the stack
case DW_OP_drop:
if (stack.empty()) {
if (error_ptr)
error_ptr->SetErrorString("Expression stack empty for DW_OP_drop.");
return false;
} else
stack.pop_back();
break;
// OPCODE: DW_OP_over
// OPERANDS: none
// DESCRIPTION: Duplicates the entry currently second in the stack at
// the top of the stack.
case DW_OP_over:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_over.");
return false;
} else
stack.push_back(stack[stack.size() - 2]);
break;
// OPCODE: DW_OP_pick
// OPERANDS: uint8_t index into the current stack
// DESCRIPTION: The stack entry with the specified index (0 through 255,
// inclusive) is pushed on the stack
case DW_OP_pick: {
uint8_t pick_idx = opcodes.GetU8(&offset);
if (pick_idx < stack.size())
stack.push_back(stack[stack.size() - 1 - pick_idx]);
else {
if (error_ptr)
error_ptr->SetErrorStringWithFormat(
"Index %u out of range for DW_OP_pick.\n", pick_idx);
return false;
}
} break;
// OPCODE: DW_OP_swap
// OPERANDS: none
// DESCRIPTION: swaps the top two stack entries. The entry at the top
// of the stack becomes the second stack entry, and the second entry
// becomes the top of the stack
case DW_OP_swap:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_swap.");
return false;
} else {
tmp = stack.back();
stack.back() = stack[stack.size() - 2];
stack[stack.size() - 2] = tmp;
}
break;
// OPCODE: DW_OP_rot
// OPERANDS: none
// DESCRIPTION: Rotates the first three stack entries. The entry at
// the top of the stack becomes the third stack entry, the second entry
// becomes the top of the stack, and the third entry becomes the second
// entry.
case DW_OP_rot:
if (stack.size() < 3) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 3 items for DW_OP_rot.");
return false;
} else {
size_t last_idx = stack.size() - 1;
Value old_top = stack[last_idx];
stack[last_idx] = stack[last_idx - 1];
stack[last_idx - 1] = stack[last_idx - 2];
stack[last_idx - 2] = old_top;
}
break;
// OPCODE: DW_OP_abs
// OPERANDS: none
// DESCRIPTION: pops the top stack entry, interprets it as a signed
// value and pushes its absolute value. If the absolute value can not be
// represented, the result is undefined.
case DW_OP_abs:
if (stack.empty()) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 1 item for DW_OP_abs.");
return false;
} else if (!stack.back().ResolveValue(exe_ctx).AbsoluteValue()) {
if (error_ptr)
error_ptr->SetErrorString(
"Failed to take the absolute value of the first stack item.");
return false;
}
break;
// OPCODE: DW_OP_and
// OPERANDS: none
// DESCRIPTION: pops the top two stack values, performs a bitwise and
// operation on the two, and pushes the result.
case DW_OP_and:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_and.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().ResolveValue(exe_ctx) =
stack.back().ResolveValue(exe_ctx) & tmp.ResolveValue(exe_ctx);
}
break;
// OPCODE: DW_OP_div
// OPERANDS: none
// DESCRIPTION: pops the top two stack values, divides the former second
// entry by the former top of the stack using signed division, and pushes
// the result.
case DW_OP_div:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_div.");
return false;
} else {
tmp = stack.back();
if (tmp.ResolveValue(exe_ctx).IsZero()) {
if (error_ptr)
error_ptr->SetErrorString("Divide by zero.");
return false;
} else {
stack.pop_back();
stack.back() =
stack.back().ResolveValue(exe_ctx) / tmp.ResolveValue(exe_ctx);
if (!stack.back().ResolveValue(exe_ctx).IsValid()) {
if (error_ptr)
error_ptr->SetErrorString("Divide failed.");
return false;
}
}
}
break;
// OPCODE: DW_OP_minus
// OPERANDS: none
// DESCRIPTION: pops the top two stack values, subtracts the former top
// of the stack from the former second entry, and pushes the result.
case DW_OP_minus:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_minus.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().ResolveValue(exe_ctx) =
stack.back().ResolveValue(exe_ctx) - tmp.ResolveValue(exe_ctx);
}
break;
// OPCODE: DW_OP_mod
// OPERANDS: none
// DESCRIPTION: pops the top two stack values and pushes the result of
// the calculation: former second stack entry modulo the former top of the
// stack.
case DW_OP_mod:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_mod.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().ResolveValue(exe_ctx) =
stack.back().ResolveValue(exe_ctx) % tmp.ResolveValue(exe_ctx);
}
break;
// OPCODE: DW_OP_mul
// OPERANDS: none
// DESCRIPTION: pops the top two stack entries, multiplies them
// together, and pushes the result.
case DW_OP_mul:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_mul.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().ResolveValue(exe_ctx) =
stack.back().ResolveValue(exe_ctx) * tmp.ResolveValue(exe_ctx);
}
break;
// OPCODE: DW_OP_neg
// OPERANDS: none
// DESCRIPTION: pops the top stack entry, and pushes its negation.
case DW_OP_neg:
if (stack.empty()) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 1 item for DW_OP_neg.");
return false;
} else {
if (!stack.back().ResolveValue(exe_ctx).UnaryNegate()) {
if (error_ptr)
error_ptr->SetErrorString("Unary negate failed.");
return false;
}
}
break;
// OPCODE: DW_OP_not
// OPERANDS: none
// DESCRIPTION: pops the top stack entry, and pushes its bitwise
// complement
case DW_OP_not:
if (stack.empty()) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 1 item for DW_OP_not.");
return false;
} else {
if (!stack.back().ResolveValue(exe_ctx).OnesComplement()) {
if (error_ptr)
error_ptr->SetErrorString("Logical NOT failed.");
return false;
}
}
break;
// OPCODE: DW_OP_or
// OPERANDS: none
// DESCRIPTION: pops the top two stack entries, performs a bitwise or
// operation on the two, and pushes the result.
case DW_OP_or:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_or.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().ResolveValue(exe_ctx) =
stack.back().ResolveValue(exe_ctx) | tmp.ResolveValue(exe_ctx);
}
break;
// OPCODE: DW_OP_plus
// OPERANDS: none
// DESCRIPTION: pops the top two stack entries, adds them together, and
// pushes the result.
case DW_OP_plus:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_plus.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().GetScalar() += tmp.GetScalar();
}
break;
// OPCODE: DW_OP_plus_uconst
// OPERANDS: none
// DESCRIPTION: pops the top stack entry, adds it to the unsigned LEB128
// constant operand and pushes the result.
case DW_OP_plus_uconst:
if (stack.empty()) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 1 item for DW_OP_plus_uconst.");
return false;
} else {
const uint64_t uconst_value = opcodes.GetULEB128(&offset);
// Implicit conversion from a UINT to a Scalar...
stack.back().GetScalar() += uconst_value;
if (!stack.back().GetScalar().IsValid()) {
if (error_ptr)
error_ptr->SetErrorString("DW_OP_plus_uconst failed.");
return false;
}
}
break;
// OPCODE: DW_OP_shl
// OPERANDS: none
// DESCRIPTION: pops the top two stack entries, shifts the former
// second entry left by the number of bits specified by the former top of
// the stack, and pushes the result.
case DW_OP_shl:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_shl.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().ResolveValue(exe_ctx) <<= tmp.ResolveValue(exe_ctx);
}
break;
// OPCODE: DW_OP_shr
// OPERANDS: none
// DESCRIPTION: pops the top two stack entries, shifts the former second
// entry right logically (filling with zero bits) by the number of bits
// specified by the former top of the stack, and pushes the result.
case DW_OP_shr:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_shr.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
if (!stack.back().ResolveValue(exe_ctx).ShiftRightLogical(
tmp.ResolveValue(exe_ctx))) {
if (error_ptr)
error_ptr->SetErrorString("DW_OP_shr failed.");
return false;
}
}
break;
// OPCODE: DW_OP_shra
// OPERANDS: none
// DESCRIPTION: pops the top two stack entries, shifts the former second
// entry right arithmetically (divide the magnitude by 2, keep the same
// sign for the result) by the number of bits specified by the former top
// of the stack, and pushes the result.
case DW_OP_shra:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_shra.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().ResolveValue(exe_ctx) >>= tmp.ResolveValue(exe_ctx);
}
break;
// OPCODE: DW_OP_xor
// OPERANDS: none
// DESCRIPTION: pops the top two stack entries, performs the bitwise
// exclusive-or operation on the two, and pushes the result.
case DW_OP_xor:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_xor.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().ResolveValue(exe_ctx) =
stack.back().ResolveValue(exe_ctx) ^ tmp.ResolveValue(exe_ctx);
}
break;
// OPCODE: DW_OP_skip
// OPERANDS: int16_t
// DESCRIPTION: An unconditional branch. Its single operand is a 2-byte
// signed integer constant. The 2-byte constant is the number of bytes of
// the DWARF expression to skip forward or backward from the current
// operation, beginning after the 2-byte constant.
case DW_OP_skip: {
int16_t skip_offset = (int16_t)opcodes.GetU16(&offset);
lldb::offset_t new_offset = offset + skip_offset;
if (opcodes.ValidOffset(new_offset))
offset = new_offset;
else {
if (error_ptr)
error_ptr->SetErrorString("Invalid opcode offset in DW_OP_skip.");
return false;
}
} break;
// OPCODE: DW_OP_bra
// OPERANDS: int16_t
// DESCRIPTION: A conditional branch. Its single operand is a 2-byte
// signed integer constant. This operation pops the top of stack. If the
// value popped is not the constant 0, the 2-byte constant operand is the
// number of bytes of the DWARF expression to skip forward or backward from
// the current operation, beginning after the 2-byte constant.
case DW_OP_bra:
if (stack.empty()) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 1 item for DW_OP_bra.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
int16_t bra_offset = (int16_t)opcodes.GetU16(&offset);
Scalar zero(0);
if (tmp.ResolveValue(exe_ctx) != zero) {
lldb::offset_t new_offset = offset + bra_offset;
if (opcodes.ValidOffset(new_offset))
offset = new_offset;
else {
if (error_ptr)
error_ptr->SetErrorString("Invalid opcode offset in DW_OP_bra.");
return false;
}
}
}
break;
// OPCODE: DW_OP_eq
// OPERANDS: none
// DESCRIPTION: pops the top two stack values, compares using the
// equals (==) operator.
// STACK RESULT: push the constant value 1 onto the stack if the result
// of the operation is true or the constant value 0 if the result of the
// operation is false.
case DW_OP_eq:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_eq.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().ResolveValue(exe_ctx) =
stack.back().ResolveValue(exe_ctx) == tmp.ResolveValue(exe_ctx);
}
break;
// OPCODE: DW_OP_ge
// OPERANDS: none
// DESCRIPTION: pops the top two stack values, compares using the
// greater than or equal to (>=) operator.
// STACK RESULT: push the constant value 1 onto the stack if the result
// of the operation is true or the constant value 0 if the result of the
// operation is false.
case DW_OP_ge:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_ge.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().ResolveValue(exe_ctx) =
stack.back().ResolveValue(exe_ctx) >= tmp.ResolveValue(exe_ctx);
}
break;
// OPCODE: DW_OP_gt
// OPERANDS: none
// DESCRIPTION: pops the top two stack values, compares using the
// greater than (>) operator.
// STACK RESULT: push the constant value 1 onto the stack if the result
// of the operation is true or the constant value 0 if the result of the
// operation is false.
case DW_OP_gt:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_gt.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().ResolveValue(exe_ctx) =
stack.back().ResolveValue(exe_ctx) > tmp.ResolveValue(exe_ctx);
}
break;
// OPCODE: DW_OP_le
// OPERANDS: none
// DESCRIPTION: pops the top two stack values, compares using the
// less than or equal to (<=) operator.
// STACK RESULT: push the constant value 1 onto the stack if the result
// of the operation is true or the constant value 0 if the result of the
// operation is false.
case DW_OP_le:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_le.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().ResolveValue(exe_ctx) =
stack.back().ResolveValue(exe_ctx) <= tmp.ResolveValue(exe_ctx);
}
break;
// OPCODE: DW_OP_lt
// OPERANDS: none
// DESCRIPTION: pops the top two stack values, compares using the
// less than (<) operator.
// STACK RESULT: push the constant value 1 onto the stack if the result
// of the operation is true or the constant value 0 if the result of the
// operation is false.
case DW_OP_lt:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_lt.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().ResolveValue(exe_ctx) =
stack.back().ResolveValue(exe_ctx) < tmp.ResolveValue(exe_ctx);
}
break;
// OPCODE: DW_OP_ne
// OPERANDS: none
// DESCRIPTION: pops the top two stack values, compares using the
// not equal (!=) operator.
// STACK RESULT: push the constant value 1 onto the stack if the result
// of the operation is true or the constant value 0 if the result of the
// operation is false.
case DW_OP_ne:
if (stack.size() < 2) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 2 items for DW_OP_ne.");
return false;
} else {
tmp = stack.back();
stack.pop_back();
stack.back().ResolveValue(exe_ctx) =
stack.back().ResolveValue(exe_ctx) != tmp.ResolveValue(exe_ctx);
}
break;
// OPCODE: DW_OP_litn
// OPERANDS: none
// DESCRIPTION: encode the unsigned literal values from 0 through 31.
// STACK RESULT: push the unsigned literal constant value onto the top
// of the stack.
case DW_OP_lit0:
case DW_OP_lit1:
case DW_OP_lit2:
case DW_OP_lit3:
case DW_OP_lit4:
case DW_OP_lit5:
case DW_OP_lit6:
case DW_OP_lit7:
case DW_OP_lit8:
case DW_OP_lit9:
case DW_OP_lit10:
case DW_OP_lit11:
case DW_OP_lit12:
case DW_OP_lit13:
case DW_OP_lit14:
case DW_OP_lit15:
case DW_OP_lit16:
case DW_OP_lit17:
case DW_OP_lit18:
case DW_OP_lit19:
case DW_OP_lit20:
case DW_OP_lit21:
case DW_OP_lit22:
case DW_OP_lit23:
case DW_OP_lit24:
case DW_OP_lit25:
case DW_OP_lit26:
case DW_OP_lit27:
case DW_OP_lit28:
case DW_OP_lit29:
case DW_OP_lit30:
case DW_OP_lit31:
stack.push_back(to_generic(op - DW_OP_lit0));
break;
// OPCODE: DW_OP_regN
// OPERANDS: none
// DESCRIPTION: Push the value in register n on the top of the stack.
case DW_OP_reg0:
case DW_OP_reg1:
case DW_OP_reg2:
case DW_OP_reg3:
case DW_OP_reg4:
case DW_OP_reg5:
case DW_OP_reg6:
case DW_OP_reg7:
case DW_OP_reg8:
case DW_OP_reg9:
case DW_OP_reg10:
case DW_OP_reg11:
case DW_OP_reg12:
case DW_OP_reg13:
case DW_OP_reg14:
case DW_OP_reg15:
case DW_OP_reg16:
case DW_OP_reg17:
case DW_OP_reg18:
case DW_OP_reg19:
case DW_OP_reg20:
case DW_OP_reg21:
case DW_OP_reg22:
case DW_OP_reg23:
case DW_OP_reg24:
case DW_OP_reg25:
case DW_OP_reg26:
case DW_OP_reg27:
case DW_OP_reg28:
case DW_OP_reg29:
case DW_OP_reg30:
case DW_OP_reg31: {
dwarf4_location_description_kind = Register;
reg_num = op - DW_OP_reg0;
if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, tmp))
stack.push_back(tmp);
else
return false;
} break;
// OPCODE: DW_OP_regx
// OPERANDS:
// ULEB128 literal operand that encodes the register.
// DESCRIPTION: Push the value in register on the top of the stack.
case DW_OP_regx: {
dwarf4_location_description_kind = Register;
reg_num = opcodes.GetULEB128(&offset);
if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, tmp))
stack.push_back(tmp);
else
return false;
} break;
// OPCODE: DW_OP_bregN
// OPERANDS:
// SLEB128 offset from register N
// DESCRIPTION: Value is in memory at the address specified by register
// N plus an offset.
case DW_OP_breg0:
case DW_OP_breg1:
case DW_OP_breg2:
case DW_OP_breg3:
case DW_OP_breg4:
case DW_OP_breg5:
case DW_OP_breg6:
case DW_OP_breg7:
case DW_OP_breg8:
case DW_OP_breg9:
case DW_OP_breg10:
case DW_OP_breg11:
case DW_OP_breg12:
case DW_OP_breg13:
case DW_OP_breg14:
case DW_OP_breg15:
case DW_OP_breg16:
case DW_OP_breg17:
case DW_OP_breg18:
case DW_OP_breg19:
case DW_OP_breg20:
case DW_OP_breg21:
case DW_OP_breg22:
case DW_OP_breg23:
case DW_OP_breg24:
case DW_OP_breg25:
case DW_OP_breg26:
case DW_OP_breg27:
case DW_OP_breg28:
case DW_OP_breg29:
case DW_OP_breg30:
case DW_OP_breg31: {
reg_num = op - DW_OP_breg0;
if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr,
tmp)) {
int64_t breg_offset = opcodes.GetSLEB128(&offset);
tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset;
tmp.ClearContext();
stack.push_back(tmp);
stack.back().SetValueType(Value::ValueType::LoadAddress);
} else
return false;
} break;
// OPCODE: DW_OP_bregx
// OPERANDS: 2
// ULEB128 literal operand that encodes the register.
// SLEB128 offset from register N
// DESCRIPTION: Value is in memory at the address specified by register
// N plus an offset.
case DW_OP_bregx: {
reg_num = opcodes.GetULEB128(&offset);
if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr,
tmp)) {
int64_t breg_offset = opcodes.GetSLEB128(&offset);
tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset;
tmp.ClearContext();
stack.push_back(tmp);
stack.back().SetValueType(Value::ValueType::LoadAddress);
} else
return false;
} break;
case DW_OP_fbreg:
if (exe_ctx) {
if (frame) {
Scalar value;
if (frame->GetFrameBaseValue(value, error_ptr)) {
int64_t fbreg_offset = opcodes.GetSLEB128(&offset);
value += fbreg_offset;
stack.push_back(value);
stack.back().SetValueType(Value::ValueType::LoadAddress);
} else
return false;
} else {
if (error_ptr)
error_ptr->SetErrorString(
"Invalid stack frame in context for DW_OP_fbreg opcode.");
return false;
}
} else {
if (error_ptr)
error_ptr->SetErrorString(
"NULL execution context for DW_OP_fbreg.\n");
return false;
}
break;
// OPCODE: DW_OP_nop
// OPERANDS: none
// DESCRIPTION: A place holder. It has no effect on the location stack
// or any of its values.
case DW_OP_nop:
break;
// OPCODE: DW_OP_piece
// OPERANDS: 1
// ULEB128: byte size of the piece
// DESCRIPTION: The operand describes the size in bytes of the piece of
// the object referenced by the DWARF expression whose result is at the top
// of the stack. If the piece is located in a register, but does not occupy
// the entire register, the placement of the piece within that register is
// defined by the ABI.
//
// Many compilers store a single variable in sets of registers, or store a
// variable partially in memory and partially in registers. DW_OP_piece
// provides a way of describing how large a part of a variable a particular
// DWARF expression refers to.
case DW_OP_piece: {
LocationDescriptionKind piece_locdesc = dwarf4_location_description_kind;
// Reset for the next piece.
dwarf4_location_description_kind = Memory;
const uint64_t piece_byte_size = opcodes.GetULEB128(&offset);
if (piece_byte_size > 0) {
Value curr_piece;
if (stack.empty()) {
UpdateValueTypeFromLocationDescription(
log, dwarf_cu, LocationDescriptionKind::Empty);
// In a multi-piece expression, this means that the current piece is
// not available. Fill with zeros for now by resizing the data and
// appending it
curr_piece.ResizeData(piece_byte_size);
// Note that "0" is not a correct value for the unknown bits.
// It would be better to also return a mask of valid bits together
// with the expression result, so the debugger can print missing
// members as "<optimized out>" or something.
::memset(curr_piece.GetBuffer().GetBytes(), 0, piece_byte_size);
pieces.AppendDataToHostBuffer(curr_piece);
} else {
Status error;
// Extract the current piece into "curr_piece"
Value curr_piece_source_value(stack.back());
stack.pop_back();
UpdateValueTypeFromLocationDescription(log, dwarf_cu, piece_locdesc,
&curr_piece_source_value);
const Value::ValueType curr_piece_source_value_type =
curr_piece_source_value.GetValueType();
switch (curr_piece_source_value_type) {
case Value::ValueType::Invalid:
return false;
case Value::ValueType::LoadAddress:
if (process) {
if (curr_piece.ResizeData(piece_byte_size) == piece_byte_size) {
lldb::addr_t load_addr =
curr_piece_source_value.GetScalar().ULongLong(
LLDB_INVALID_ADDRESS);
if (process->ReadMemory(
load_addr, curr_piece.GetBuffer().GetBytes(),
piece_byte_size, error) != piece_byte_size) {
if (error_ptr)
error_ptr->SetErrorStringWithFormat(
"failed to read memory DW_OP_piece(%" PRIu64
") from 0x%" PRIx64,
piece_byte_size, load_addr);
return false;
}
} else {
if (error_ptr)
error_ptr->SetErrorStringWithFormat(
"failed to resize the piece memory buffer for "
"DW_OP_piece(%" PRIu64 ")",
piece_byte_size);
return false;
}
}
break;
case Value::ValueType::FileAddress:
case Value::ValueType::HostAddress:
if (error_ptr) {
lldb::addr_t addr = curr_piece_source_value.GetScalar().ULongLong(
LLDB_INVALID_ADDRESS);
error_ptr->SetErrorStringWithFormat(
"failed to read memory DW_OP_piece(%" PRIu64
") from %s address 0x%" PRIx64,
piece_byte_size, curr_piece_source_value.GetValueType() ==
Value::ValueType::FileAddress
? "file"
: "host",
addr);
}
return false;
case Value::ValueType::Scalar: {
uint32_t bit_size = piece_byte_size * 8;
uint32_t bit_offset = 0;
Scalar &scalar = curr_piece_source_value.GetScalar();
if (!scalar.ExtractBitfield(
bit_size, bit_offset)) {
if (error_ptr)
error_ptr->SetErrorStringWithFormat(
"unable to extract %" PRIu64 " bytes from a %" PRIu64
" byte scalar value.",
piece_byte_size,
(uint64_t)curr_piece_source_value.GetScalar()
.GetByteSize());
return false;
}
// Create curr_piece with bit_size. By default Scalar
// grows to the nearest host integer type.
llvm::APInt fail_value(1, 0, false);
llvm::APInt ap_int = scalar.UInt128(fail_value);
assert(ap_int.getBitWidth() >= bit_size);
llvm::ArrayRef<uint64_t> buf{ap_int.getRawData(),
ap_int.getNumWords()};
curr_piece.GetScalar() = Scalar(llvm::APInt(bit_size, buf));
} break;
}
// Check if this is the first piece?
if (op_piece_offset == 0) {
// This is the first piece, we should push it back onto the stack
// so subsequent pieces will be able to access this piece and add
// to it.
if (pieces.AppendDataToHostBuffer(curr_piece) == 0) {
if (error_ptr)
error_ptr->SetErrorString("failed to append piece data");
return false;
}
} else {
// If this is the second or later piece there should be a value on
// the stack.
if (pieces.GetBuffer().GetByteSize() != op_piece_offset) {
if (error_ptr)
error_ptr->SetErrorStringWithFormat(
"DW_OP_piece for offset %" PRIu64
" but top of stack is of size %" PRIu64,
op_piece_offset, pieces.GetBuffer().GetByteSize());
return false;
}
if (pieces.AppendDataToHostBuffer(curr_piece) == 0) {
if (error_ptr)
error_ptr->SetErrorString("failed to append piece data");
return false;
}
}
}
op_piece_offset += piece_byte_size;
}
} break;
case DW_OP_bit_piece: // 0x9d ULEB128 bit size, ULEB128 bit offset (DWARF3);
if (stack.size() < 1) {
UpdateValueTypeFromLocationDescription(log, dwarf_cu,
LocationDescriptionKind::Empty);
// Reset for the next piece.
dwarf4_location_description_kind = Memory;
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 1 item for DW_OP_bit_piece.");
return false;
} else {
UpdateValueTypeFromLocationDescription(
log, dwarf_cu, dwarf4_location_description_kind, &stack.back());
// Reset for the next piece.
dwarf4_location_description_kind = Memory;
const uint64_t piece_bit_size = opcodes.GetULEB128(&offset);
const uint64_t piece_bit_offset = opcodes.GetULEB128(&offset);
switch (stack.back().GetValueType()) {
case Value::ValueType::Invalid:
return false;
case Value::ValueType::Scalar: {
if (!stack.back().GetScalar().ExtractBitfield(piece_bit_size,
piece_bit_offset)) {
if (error_ptr)
error_ptr->SetErrorStringWithFormat(
"unable to extract %" PRIu64 " bit value with %" PRIu64
" bit offset from a %" PRIu64 " bit scalar value.",
piece_bit_size, piece_bit_offset,
(uint64_t)(stack.back().GetScalar().GetByteSize() * 8));
return false;
}
} break;
case Value::ValueType::FileAddress:
case Value::ValueType::LoadAddress:
case Value::ValueType::HostAddress:
if (error_ptr) {
error_ptr->SetErrorStringWithFormat(
"unable to extract DW_OP_bit_piece(bit_size = %" PRIu64
", bit_offset = %" PRIu64 ") from an address value.",
piece_bit_size, piece_bit_offset);
}
return false;
}
}
break;
// OPCODE: DW_OP_implicit_value
// OPERANDS: 2
// ULEB128 size of the value block in bytes
// uint8_t* block bytes encoding value in target's memory
// representation
// DESCRIPTION: Value is immediately stored in block in the debug info with
// the memory representation of the target.
case DW_OP_implicit_value: {
dwarf4_location_description_kind = Implicit;
const uint32_t len = opcodes.GetULEB128(&offset);
const void *data = opcodes.GetData(&offset, len);
if (!data) {
LLDB_LOG(log, "Evaluate_DW_OP_implicit_value: could not be read data");
LLDB_ERRORF(error_ptr, "Could not evaluate %s.",
DW_OP_value_to_name(op));
return false;
}
Value result(data, len);
stack.push_back(result);
break;
}
case DW_OP_implicit_pointer: {
dwarf4_location_description_kind = Implicit;
LLDB_ERRORF(error_ptr, "Could not evaluate %s.", DW_OP_value_to_name(op));
return false;
}
// OPCODE: DW_OP_push_object_address
// OPERANDS: none
// DESCRIPTION: Pushes the address of the object currently being
// evaluated as part of evaluation of a user presented expression. This
// object may correspond to an independent variable described by its own
// DIE or it may be a component of an array, structure, or class whose
// address has been dynamically determined by an earlier step during user
// expression evaluation.
case DW_OP_push_object_address:
if (object_address_ptr)
stack.push_back(*object_address_ptr);
else {
if (error_ptr)
error_ptr->SetErrorString("DW_OP_push_object_address used without "
"specifying an object address");
return false;
}
break;
// OPCODE: DW_OP_call2
// OPERANDS:
// uint16_t compile unit relative offset of a DIE
// DESCRIPTION: Performs subroutine calls during evaluation
// of a DWARF expression. The operand is the 2-byte unsigned offset of a
// debugging information entry in the current compilation unit.
//
// Operand interpretation is exactly like that for DW_FORM_ref2.
//
// This operation transfers control of DWARF expression evaluation to the
// DW_AT_location attribute of the referenced DIE. If there is no such
// attribute, then there is no effect. Execution of the DWARF expression of
// a DW_AT_location attribute may add to and/or remove from values on the
// stack. Execution returns to the point following the call when the end of
// the attribute is reached. Values on the stack at the time of the call
// may be used as parameters by the called expression and values left on
// the stack by the called expression may be used as return values by prior
// agreement between the calling and called expressions.
case DW_OP_call2:
if (error_ptr)
error_ptr->SetErrorString("Unimplemented opcode DW_OP_call2.");
return false;
// OPCODE: DW_OP_call4
// OPERANDS: 1
// uint32_t compile unit relative offset of a DIE
// DESCRIPTION: Performs a subroutine call during evaluation of a DWARF
// expression. For DW_OP_call4, the operand is a 4-byte unsigned offset of
// a debugging information entry in the current compilation unit.
//
// Operand interpretation DW_OP_call4 is exactly like that for
// DW_FORM_ref4.
//
// This operation transfers control of DWARF expression evaluation to the
// DW_AT_location attribute of the referenced DIE. If there is no such
// attribute, then there is no effect. Execution of the DWARF expression of
// a DW_AT_location attribute may add to and/or remove from values on the
// stack. Execution returns to the point following the call when the end of
// the attribute is reached. Values on the stack at the time of the call
// may be used as parameters by the called expression and values left on
// the stack by the called expression may be used as return values by prior
// agreement between the calling and called expressions.
case DW_OP_call4:
if (error_ptr)
error_ptr->SetErrorString("Unimplemented opcode DW_OP_call4.");
return false;
// OPCODE: DW_OP_stack_value
// OPERANDS: None
// DESCRIPTION: Specifies that the object does not exist in memory but
// rather is a constant value. The value from the top of the stack is the
// value to be used. This is the actual object value and not the location.
case DW_OP_stack_value:
dwarf4_location_description_kind = Implicit;
if (stack.empty()) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 1 item for DW_OP_stack_value.");
return false;
}
stack.back().SetValueType(Value::ValueType::Scalar);
break;
// OPCODE: DW_OP_convert
// OPERANDS: 1
// A ULEB128 that is either a DIE offset of a
// DW_TAG_base_type or 0 for the generic (pointer-sized) type.
//
// DESCRIPTION: Pop the top stack element, convert it to a
// different type, and push the result.
case DW_OP_convert: {
if (stack.size() < 1) {
if (error_ptr)
error_ptr->SetErrorString(
"Expression stack needs at least 1 item for DW_OP_convert.");
return false;
}
const uint64_t die_offset = opcodes.GetULEB128(&offset);
uint64_t bit_size;
bool sign;
if (die_offset == 0) {
// The generic type has the size of an address on the target
// machine and an unspecified signedness. Scalar has no
// "unspecified signedness", so we use unsigned types.
if (!module_sp) {
if (error_ptr)
error_ptr->SetErrorString("No module");
return false;
}
sign = false;
bit_size = module_sp->GetArchitecture().GetAddressByteSize() * 8;
if (!bit_size) {
if (error_ptr)
error_ptr->SetErrorString("unspecified architecture");
return false;
}
} else {
// Retrieve the type DIE that the value is being converted to.
// FIXME: the constness has annoying ripple effects.
DWARFDIE die = const_cast<DWARFUnit *>(dwarf_cu)->GetDIE(die_offset);
if (!die) {
if (error_ptr)
error_ptr->SetErrorString("Cannot resolve DW_OP_convert type DIE");
return false;
}
uint64_t encoding =
die.GetAttributeValueAsUnsigned(DW_AT_encoding, DW_ATE_hi_user);
bit_size = die.GetAttributeValueAsUnsigned(DW_AT_byte_size, 0) * 8;
if (!bit_size)
bit_size = die.GetAttributeValueAsUnsigned(DW_AT_bit_size, 0);
if (!bit_size) {
if (error_ptr)
error_ptr->SetErrorString("Unsupported type size in DW_OP_convert");
return false;
}
switch (encoding) {
case DW_ATE_signed:
case DW_ATE_signed_char:
sign = true;
break;
case DW_ATE_unsigned:
case DW_ATE_unsigned_char:
sign = false;
break;
default:
if (error_ptr)
error_ptr->SetErrorString("Unsupported encoding in DW_OP_convert");
return false;
}
}
Scalar &top = stack.back().ResolveValue(exe_ctx);
top.TruncOrExtendTo(bit_size, sign);
break;
}
// OPCODE: DW_OP_call_frame_cfa
// OPERANDS: None
// DESCRIPTION: Specifies a DWARF expression that pushes the value of
// the canonical frame address consistent with the call frame information
// located in .debug_frame (or in the FDEs of the eh_frame section).
case DW_OP_call_frame_cfa:
if (frame) {
// Note that we don't have to parse FDEs because this DWARF expression
// is commonly evaluated with a valid stack frame.
StackID id = frame->GetStackID();
addr_t cfa = id.GetCallFrameAddress();
if (cfa != LLDB_INVALID_ADDRESS) {
stack.push_back(Scalar(cfa));
stack.back().SetValueType(Value::ValueType::LoadAddress);
} else if (error_ptr)
error_ptr->SetErrorString("Stack frame does not include a canonical "
"frame address for DW_OP_call_frame_cfa "
"opcode.");
} else {
if (error_ptr)
error_ptr->SetErrorString("Invalid stack frame in context for "
"DW_OP_call_frame_cfa opcode.");
return false;
}
break;
// OPCODE: DW_OP_form_tls_address (or the old pre-DWARFv3 vendor extension
// opcode, DW_OP_GNU_push_tls_address)
// OPERANDS: none
// DESCRIPTION: Pops a TLS offset from the stack, converts it to
// an address in the current thread's thread-local storage block, and
// pushes it on the stack.
case DW_OP_form_tls_address:
case DW_OP_GNU_push_tls_address: {
if (stack.size() < 1) {
if (error_ptr) {
if (op == DW_OP_form_tls_address)
error_ptr->SetErrorString(
"DW_OP_form_tls_address needs an argument.");
else
error_ptr->SetErrorString(
"DW_OP_GNU_push_tls_address needs an argument.");
}
return false;
}
if (!exe_ctx || !module_sp) {
if (error_ptr)
error_ptr->SetErrorString("No context to evaluate TLS within.");
return false;
}
Thread *thread = exe_ctx->GetThreadPtr();
if (!thread) {
if (error_ptr)
error_ptr->SetErrorString("No thread to evaluate TLS within.");
return false;
}
// Lookup the TLS block address for this thread and module.
const addr_t tls_file_addr =
stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
const addr_t tls_load_addr =
thread->GetThreadLocalData(module_sp, tls_file_addr);
if (tls_load_addr == LLDB_INVALID_ADDRESS) {
if (error_ptr)
error_ptr->SetErrorString(
"No TLS data currently exists for this thread.");
return false;
}
stack.back().GetScalar() = tls_load_addr;
stack.back().SetValueType(Value::ValueType::LoadAddress);
} break;
// OPCODE: DW_OP_addrx (DW_OP_GNU_addr_index is the legacy name.)
// OPERANDS: 1
// ULEB128: index to the .debug_addr section
// DESCRIPTION: Pushes an address to the stack from the .debug_addr
// section with the base address specified by the DW_AT_addr_base attribute
// and the 0 based index is the ULEB128 encoded index.
case DW_OP_addrx:
case DW_OP_GNU_addr_index: {
if (!dwarf_cu) {
if (error_ptr)
error_ptr->SetErrorString("DW_OP_GNU_addr_index found without a "
"compile unit being specified");
return false;
}
uint64_t index = opcodes.GetULEB128(&offset);
lldb::addr_t value = ReadAddressFromDebugAddrSection(dwarf_cu, index);
stack.push_back(Scalar(value));
stack.back().SetValueType(Value::ValueType::FileAddress);
} break;
// OPCODE: DW_OP_GNU_const_index
// OPERANDS: 1
// ULEB128: index to the .debug_addr section
// DESCRIPTION: Pushes an constant with the size of a machine address to
// the stack from the .debug_addr section with the base address specified
// by the DW_AT_addr_base attribute and the 0 based index is the ULEB128
// encoded index.
case DW_OP_GNU_const_index: {
if (!dwarf_cu) {
if (error_ptr)
error_ptr->SetErrorString("DW_OP_GNU_const_index found without a "
"compile unit being specified");
return false;
}
uint64_t index = opcodes.GetULEB128(&offset);
lldb::addr_t value = ReadAddressFromDebugAddrSection(dwarf_cu, index);
stack.push_back(Scalar(value));
} break;
case DW_OP_GNU_entry_value:
case DW_OP_entry_value: {
if (!Evaluate_DW_OP_entry_value(stack, exe_ctx, reg_ctx, opcodes, offset,
error_ptr, log)) {
LLDB_ERRORF(error_ptr, "Could not evaluate %s.",
DW_OP_value_to_name(op));
return false;
}
break;
}
default:
if (error_ptr)
error_ptr->SetErrorStringWithFormatv(
"Unhandled opcode {0} in DWARFExpression", LocationAtom(op));
return false;
}
}
if (stack.empty()) {
// Nothing on the stack, check if we created a piece value from DW_OP_piece
// or DW_OP_bit_piece opcodes
if (pieces.GetBuffer().GetByteSize()) {
result = pieces;
return true;
}
if (error_ptr)
error_ptr->SetErrorString("Stack empty after evaluation.");
return false;
}
UpdateValueTypeFromLocationDescription(
log, dwarf_cu, dwarf4_location_description_kind, &stack.back());
if (log && log->GetVerbose()) {
size_t count = stack.size();
LLDB_LOGF(log,
"Stack after operation has %" PRIu64 " values:", (uint64_t)count);
for (size_t i = 0; i < count; ++i) {
StreamString new_value;
new_value.Printf("[%" PRIu64 "]", (uint64_t)i);
stack[i].Dump(&new_value);
LLDB_LOGF(log, " %s", new_value.GetData());
}
}
result = stack.back();
return true; // Return true on success
}