src/developer/debug/zxdb/symbols/dwarf_location.h

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef SRC_DEVELOPER_DEBUG_ZXDB_SYMBOLS_DWARF_LOCATION_H_
#define SRC_DEVELOPER_DEBUG_ZXDB_SYMBOLS_DWARF_LOCATION_H_

#include "lib/fit/function.h"
#include "src/developer/debug/zxdb/symbols/arch.h"
#include "src/developer/debug/zxdb/symbols/variable_location.h"
#include "src/lib/containers/cpp/array_view.h"

namespace llvm {
class DWARFUnit;
class DWARFFormValue;
}  // namespace llvm

namespace zxdb {

// Decodes the variable location contained in the given form value. It's assumed the form value
// contains either a block, an ExprLoc, or an offset into the .debug_loc section.
//
// The source is the symbol that created this location entry, it will be passed to the
// VariableLocation.
//
// On error this will return an empty VariableLocation.
VariableLocation DecodeVariableLocation(llvm::DWARFUnit* unit, const llvm::DWARFFormValue& form,
                                        const UncachedLazySymbol& source);

// Low-level decode for a DWARF 4 variable location description. The data should start at the
// beginning of the location list to parse, and cover as much data as the location list could
// possibly cover (normally the end of the .debug_loc section).
//
// The source is the symbol that created this location entry, it will be passed to the
// VariableLocation.
//
// On error this will return an empty VariableLocation.
VariableLocation DecodeDwarf4LocationList(TargetPointer unit_base_addr,
                                          containers::array_view<uint8_t> data,
                                          const UncachedLazySymbol& source);

// Low-level decode for a DWARF 5 variable location description. The data should start at the
// beginning of the location list to parse, and cover as much data as the location list could
// possibly cover (normally the end of the .debug_loclist section).
//
// The index_to_addr function will convert an "addrx" index into the .debug_addr table to the
// corresponding module-relative address. It should return nullopt on failure.
//
// The source is the symbol that created this location entry, it will be passed to the
// VariableLocation.
//
// On error this will return an empty VariableLocation.
VariableLocation DecodeDwarf5LocationList(
    TargetPointer unit_base_addr, containers::array_view<uint8_t> data,
    fit::function<std::optional<TargetPointer>(uint64_t)>& index_to_addr,
    const UncachedLazySymbol& source);

}  // namespace zxdb

#endif  // SRC_DEVELOPER_DEBUG_ZXDB_SYMBOLS_DWARF_LOCATION_H_