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-rw-r--r--Common/DWARF.cpp103
1 files changed, 103 insertions, 0 deletions
diff --git a/Common/DWARF.cpp b/Common/DWARF.cpp
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+//===- 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.
+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 None;
+
+ // Take file name string from line table.
+ std::string fileName;
+ if (!it->second.lt->getFileNameByIndex(
+ it->second.file, {},
+ DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, fileName))
+ return None;
+
+ return std::make_pair(fileName, it->second.line);
+}
+
+// Returns source line information for a given offset
+// using DWARF debug info.
+Optional<DILineInfo> DWARFCache::getDILineInfo(uint64_t offset,
+ uint64_t sectionIndex) {
+ DILineInfo info;
+ for (const llvm::DWARFDebugLine::LineTable *lt : lineTables) {
+ if (lt->getFileLineInfoForAddress(
+ {offset, sectionIndex}, nullptr,
+ DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, info))
+ return info;
+ }
+ return None;
+}
+
+} // namespace lld