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0886440ef0
LLVM Symbolizer attempt to symbolize addresses of optimized binaries reports missing line numbers for some cases. It maybe due to compiler which sometimes cannot map an instruction to line number due to optimizations. Symbolizer should handle those cases gracefully. Adding an option '--skip-line-zero' to symbolizer so as to report the nearest non-zero line number. --------- Co-authored-by: Amit Pandey <amit.pandey@amd.com>
104 lines
3.8 KiB
C++
104 lines
3.8 KiB
C++
//===- DWARF.cpp ----------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "lld/Common/DWARF.h"
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#include "lld/Common/ErrorHandler.h"
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using namespace llvm;
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namespace lld {
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DWARFCache::DWARFCache(std::unique_ptr<llvm::DWARFContext> d)
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: dwarf(std::move(d)) {
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for (std::unique_ptr<DWARFUnit> &cu : dwarf->compile_units()) {
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auto report = [](Error err) {
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handleAllErrors(std::move(err),
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[](ErrorInfoBase &info) { warn(info.message()); });
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};
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Expected<const DWARFDebugLine::LineTable *> expectedLT =
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dwarf->getLineTableForUnit(cu.get(), report);
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const DWARFDebugLine::LineTable *lt = nullptr;
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if (expectedLT)
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lt = *expectedLT;
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else
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report(expectedLT.takeError());
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if (!lt)
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continue;
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lineTables.push_back(lt);
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// Loop over variable records and insert them to variableLoc.
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for (const auto &entry : cu->dies()) {
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DWARFDie die(cu.get(), &entry);
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// Skip all tags that are not variables.
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if (die.getTag() != dwarf::DW_TAG_variable)
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continue;
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// Skip if a local variable because we don't need them for generating
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// error messages. In general, only non-local symbols can fail to be
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// linked.
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if (!dwarf::toUnsigned(die.find(dwarf::DW_AT_external), 0))
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continue;
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// Get the source filename index for the variable.
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unsigned file = dwarf::toUnsigned(die.find(dwarf::DW_AT_decl_file), 0);
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if (!lt->hasFileAtIndex(file))
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continue;
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// Get the line number on which the variable is declared.
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unsigned line = dwarf::toUnsigned(die.find(dwarf::DW_AT_decl_line), 0);
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// Here we want to take the variable name to add it into variableLoc.
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// Variable can have regular and linkage name associated. At first, we try
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// to get linkage name as it can be different, for example when we have
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// two variables in different namespaces of the same object. Use common
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// name otherwise, but handle the case when it also absent in case if the
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// input object file lacks some debug info.
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StringRef name =
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dwarf::toString(die.find(dwarf::DW_AT_linkage_name),
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dwarf::toString(die.find(dwarf::DW_AT_name), ""));
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if (!name.empty())
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variableLoc.insert({name, {lt, file, line}});
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}
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}
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}
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// Returns the pair of file name and line number describing location of data
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// object (variable, array, etc) definition.
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std::optional<std::pair<std::string, unsigned>>
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DWARFCache::getVariableLoc(StringRef name) {
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// Return if we have no debug information about data object.
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auto it = variableLoc.find(name);
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if (it == variableLoc.end())
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return std::nullopt;
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// Take file name string from line table.
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std::string fileName;
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if (!it->second.lt->getFileNameByIndex(
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it->second.file, {},
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DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, fileName))
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return std::nullopt;
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return std::make_pair(fileName, it->second.line);
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}
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// Returns source line information for a given offset
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// using DWARF debug info.
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std::optional<DILineInfo> DWARFCache::getDILineInfo(uint64_t offset,
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uint64_t sectionIndex) {
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DILineInfo info;
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for (const llvm::DWARFDebugLine::LineTable *lt : lineTables) {
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if (lt->getFileLineInfoForAddress(
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{offset, sectionIndex}, false, nullptr,
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DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, info))
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return info;
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}
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return std::nullopt;
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}
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} // namespace lld
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