| //===- DWARF.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 "lld/Common/DWARF.h" |
| #include "lld/Common/ErrorHandler.h" |
| |
| using namespace llvm; |
| |
| namespace lld { |
| |
| DWARFCache::DWARFCache(std::unique_ptr<llvm::DWARFContext> d) |
| : dwarf(std::move(d)) { |
| for (std::unique_ptr<DWARFUnit> &cu : dwarf->compile_units()) { |
| auto report = [](Error err) { |
| handleAllErrors(std::move(err), |
| [](ErrorInfoBase &info) { warn(info.message()); }); |
| }; |
| Expected<const DWARFDebugLine::LineTable *> expectedLT = |
| dwarf->getLineTableForUnit(cu.get(), report); |
| const DWARFDebugLine::LineTable *lt = nullptr; |
| if (expectedLT) |
| lt = *expectedLT; |
| else |
| report(expectedLT.takeError()); |
| if (!lt) |
| continue; |
| lineTables.push_back(lt); |
| |
| // Loop over variable records and insert them to variableLoc. |
| for (const auto &entry : cu->dies()) { |
| DWARFDie die(cu.get(), &entry); |
| // Skip all tags that are not variables. |
| if (die.getTag() != dwarf::DW_TAG_variable) |
| continue; |
| |
| // Skip if a local variable because we don't need them for generating |
| // error messages. In general, only non-local symbols can fail to be |
| // linked. |
| if (!dwarf::toUnsigned(die.find(dwarf::DW_AT_external), 0)) |
| continue; |
| |
| // Get the source filename index for the variable. |
| unsigned file = dwarf::toUnsigned(die.find(dwarf::DW_AT_decl_file), 0); |
| if (!lt->hasFileAtIndex(file)) |
| continue; |
| |
| // Get the line number on which the variable is declared. |
| unsigned line = dwarf::toUnsigned(die.find(dwarf::DW_AT_decl_line), 0); |
| |
| // Here we want to take the variable name to add it into variableLoc. |
| // Variable can have regular and linkage name associated. At first, we try |
| // to get linkage name as it can be different, for example when we have |
| // two variables in different namespaces of the same object. Use common |
| // name otherwise, but handle the case when it also absent in case if the |
| // input object file lacks some debug info. |
| StringRef name = |
| dwarf::toString(die.find(dwarf::DW_AT_linkage_name), |
| dwarf::toString(die.find(dwarf::DW_AT_name), "")); |
| if (!name.empty()) |
| variableLoc.insert({name, {lt, file, line}}); |
| } |
| } |
| } |
| |
| // Returns the pair of file name and line number describing location of data |
| // object (variable, array, etc) definition. |
| std::optional<std::pair<std::string, unsigned>> |
| DWARFCache::getVariableLoc(StringRef name) { |
| // Return if we have no debug information about data object. |
| auto it = variableLoc.find(name); |
| if (it == variableLoc.end()) |
| return std::nullopt; |
| |
| // Take file name string from line table. |
| std::string fileName; |
| if (!it->second.lt->getFileNameByIndex( |
| it->second.file, {}, |
| DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, fileName)) |
| return std::nullopt; |
| |
| return std::make_pair(fileName, it->second.line); |
| } |
| |
| // Returns source line information for a given offset |
| // using DWARF debug info. |
| std::optional<DILineInfo> DWARFCache::getDILineInfo(uint64_t offset, |
| uint64_t sectionIndex) { |
| DILineInfo info; |
| for (const llvm::DWARFDebugLine::LineTable *lt : lineTables) { |
| if (lt->getFileLineInfoForAddress( |
| {offset, sectionIndex}, false, nullptr, |
| DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, info)) |
| return info; |
| } |
| return std::nullopt; |
| } |
| |
| } // namespace lld |