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//===-- DWARFExpression.h ---------------------------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef LLDB_EXPRESSION_DWARFEXPRESSION_H
#define LLDB_EXPRESSION_DWARFEXPRESSION_H
#include "lldb/Core/Address.h"
#include "lldb/Core/Disassembler.h"
#include "lldb/Utility/DataExtractor.h"
#include "lldb/Utility/Scalar.h"
#include "lldb/Utility/Status.h"
#include "lldb/lldb-private.h"
#include "llvm/DebugInfo/DWARF/DWARFLocationExpression.h"
#include <functional>
namespace lldb_private {
namespace plugin {
namespace dwarf {
class DWARFUnit;
} // namespace dwarf
} // namespace plugin
/// \class DWARFExpression DWARFExpression.h
/// "lldb/Expression/DWARFExpression.h" Encapsulates a DWARF location
/// expression and interprets it.
///
/// DWARF location expressions are used in two ways by LLDB. The first
/// use is to find entities specified in the debug information, since their
/// locations are specified in precisely this language. The second is to
/// interpret expressions without having to run the target in cases where the
/// overhead from copying JIT-compiled code into the target is too high or
/// where the target cannot be run. This class encapsulates a single DWARF
/// location expression or a location list and interprets it.
class DWARFExpression {
public:
DWARFExpression();
/// Constructor
///
/// \param[in] data
/// A data extractor configured to read the DWARF location expression's
/// bytecode.
DWARFExpression(const DataExtractor &data);
/// Destructor
~DWARFExpression();
/// Return true if the location expression contains data
bool IsValid() const;
/// Return the address specified by the first
/// DW_OP_{addr, addrx, GNU_addr_index} in the operation stream.
///
/// \param[in] dwarf_cu
/// The dwarf unit this expression belongs to. Only required to resolve
/// DW_OP{addrx, GNU_addr_index}.
///
/// \param[out] error
/// If the location stream contains unknown DW_OP opcodes or the
/// data is missing, \a error will be set to \b true.
///
/// \return
/// The address specified by the operation, if the operation exists, or
/// LLDB_INVALID_ADDRESS otherwise.
lldb::addr_t GetLocation_DW_OP_addr(const plugin::dwarf::DWARFUnit *dwarf_cu,
bool &error) const;
bool Update_DW_OP_addr(const plugin::dwarf::DWARFUnit *dwarf_cu,
lldb::addr_t file_addr);
void UpdateValue(uint64_t const_value, lldb::offset_t const_value_byte_size,
uint8_t addr_byte_size);
bool
ContainsThreadLocalStorage(const plugin::dwarf::DWARFUnit *dwarf_cu) const;
bool LinkThreadLocalStorage(
const plugin::dwarf::DWARFUnit *dwarf_cu,
std::function<lldb::addr_t(lldb::addr_t file_addr)> const
&link_address_callback);
/// Return the call-frame-info style register kind
lldb::RegisterKind GetRegisterKind() const;
/// Set the call-frame-info style register kind
///
/// \param[in] reg_kind
/// The register kind.
void SetRegisterKind(lldb::RegisterKind reg_kind);
/// Evaluate a DWARF location expression in a particular context
///
/// \param[in] exe_ctx
/// The execution context in which to evaluate the location
/// expression. The location expression may access the target's
/// memory, especially if it comes from the expression parser.
///
/// \param[in] opcode_ctx
/// The module which defined the expression.
///
/// \param[in] opcodes
/// This is a static method so the opcodes need to be provided
/// explicitly.
///
/// \param[in] reg_ctx
/// An optional parameter which provides a RegisterContext for use
/// when evaluating the expression (i.e. for fetching register values).
/// Normally this will come from the ExecutionContext's StackFrame but
/// in the case where an expression needs to be evaluated while building
/// the stack frame list, this short-cut is available.
///
/// \param[in] reg_set
/// The call-frame-info style register kind.
///
/// \param[in] initial_value_ptr
/// A value to put on top of the interpreter stack before evaluating
/// the expression, if the expression is parametrized. Can be NULL.
///
/// \param[in] result
/// A value into which the result of evaluating the expression is
/// to be placed.
///
/// \param[in] error_ptr
/// If non-NULL, used to report errors in expression evaluation.
///
/// \return
/// True on success; false otherwise. If error_ptr is non-NULL,
/// details of the failure are provided through it.
static bool Evaluate(ExecutionContext *exe_ctx, RegisterContext *reg_ctx,
lldb::ModuleSP module_sp, const DataExtractor &opcodes,
const plugin::dwarf::DWARFUnit *dwarf_cu,
const lldb::RegisterKind reg_set,
const Value *initial_value_ptr,
const Value *object_address_ptr, Value &result,
Status *error_ptr);
static bool ParseDWARFLocationList(const plugin::dwarf::DWARFUnit *dwarf_cu,
const DataExtractor &data,
DWARFExpressionList *loc_list);
bool GetExpressionData(DataExtractor &data) const {
data = m_data;
return data.GetByteSize() > 0;
}
void DumpLocation(Stream *s, lldb::DescriptionLevel level, ABI *abi) const;
bool MatchesOperand(StackFrame &frame, const Instruction::Operand &op) const;
private:
/// A data extractor capable of reading opcode bytes
DataExtractor m_data;
/// One of the defines that starts with LLDB_REGKIND_
lldb::RegisterKind m_reg_kind = lldb::eRegisterKindDWARF;
};
} // namespace lldb_private
#endif // LLDB_EXPRESSION_DWARFEXPRESSION_H