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104 lines
3.7 KiB
C++
104 lines
3.7 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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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 None;
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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 None;
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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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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}, nullptr,
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DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, info))
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return info;
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}
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return None;
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}
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} // namespace lld
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