Files
clang-p2996/lldb/source/Plugins/SymbolFile/DWARF/DWARFContext.cpp
Zachary Turner 6e66512758 Introduce DWARFContext.
LLVM's DWARF parsing library has a class called DWARFContext which holds
all of the various DWARF data sections and lots of other information.
LLDB's on the other hand stores all of this directly in SymbolFileDWARF
/ SymbolFileDWARFDwo and passes this interface around through the
parsing library. Obviously this is incompatible with a world where the
low level interface does not depend on the high level interface, so we
need to move towards a model similar to LLVM's - i.e. all of the context
needed for low level parsing should be in a single class, and that class
gets passed around.

This patch is a small incremental step towards achieving this. The
interface and internals deviate from LLVM's for technical reasons, but
the high level idea is the same. The goal is, eventually, to remove all
occurrences of SymbolFileDWARF from the low level parsing code.

For now I've chosen a very simple section - the .debug_aranges section
to move into DWARFContext while leaving everything else unchanged. In
the short term this is a bit confusing because now the information you
need might come from either of 2 different locations. But it's a huge
refactor to do this all at once and runs a much higher risk of breaking
things. So I think it would be wise to do this in very small pieces.

TL;DR - No functional change

Differential Revision: https://reviews.llvm.org/D59562

llvm-svn: 356612
2019-03-20 20:49:25 +00:00

44 lines
1.4 KiB
C++

//===-- DWARFContext.cpp ----------------------------------------*- C++ -*-===//
//
// 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 "DWARFContext.h"
#include "lldb/Core/Section.h"
using namespace lldb;
using namespace lldb_private;
static const DWARFDataExtractor *
LoadOrGetSection(Module &module, SectionType section_type,
llvm::Optional<DWARFDataExtractor> &extractor) {
if (extractor.hasValue())
return extractor->GetByteSize() > 0 ? extractor.getPointer() : nullptr;
// Initialize to an empty extractor so that we always take the fast path going
// forward.
extractor.emplace();
const SectionList *section_list = module.GetSectionList();
if (!section_list)
return nullptr;
auto section_sp = section_list->FindSectionByType(section_type, true);
if (!section_sp)
return nullptr;
section_sp->GetSectionData(*extractor);
return extractor.getPointer();
}
DWARFContext::DWARFContext(Module &module) : m_module(module) {}
const DWARFDataExtractor *DWARFContext::getOrLoadArangesData() {
return LoadOrGetSection(m_module, eSectionTypeDWARFDebugAranges,
m_data_debug_aranges);
}