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//===- "DependencyTracker.h" ------------------------------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "DWARFLinkerCompileUnit.h"
#include "DWARFLinkerImpl.h"
#include "llvm/ADT/SmallVector.h"
namespace llvm {
class DWARFDebugInfoEntry;
class DWARFDie;
namespace dwarflinker_parallel {
/// This class discovers DIEs dependencies and marks "live" DIEs.
class DependencyTracker {
DependencyTracker(DWARFLinkerImpl::LinkContext &Context) : Context(Context) {}
/// Recursively walk the \p DIE tree and look for DIEs to keep. Store that
/// information in \p CU's DIEInfo.
/// This function is the entry point of the DIE selection algorithm. It is
/// expected to walk the DIE tree and(through the mediation of
/// Context.File.Addresses) ask for relocation adjustment value on each
/// DIE that might be a 'root DIE'.
/// Returns true if all dependencies are correctly discovered. Inter-CU
/// dependencies cannot be discovered if referenced CU is not analyzed yet.
/// If that is the case this method returns false.
bool resolveDependenciesAndMarkLiveness(CompileUnit &CU);
/// Recursively walk the \p DIE tree and check "keepness" information.
/// It is an error if parent node does not have "keep" flag, while
/// child have one. This function dump error at stderr in that case.
#ifndef NDEBUG
static void verifyKeepChain(CompileUnit &CU);
struct RootEntryTy {
RootEntryTy(CompileUnit &CU, const DWARFDebugInfoEntry *RootEntry)
: CU(CU), RootEntry(RootEntry) {}
// Compile unit keeping root entry.
CompileUnit &CU;
// Root entry.
const DWARFDebugInfoEntry *RootEntry;
using RootEntriesListTy = SmallVector<RootEntryTy>;
/// This function navigates DIEs tree starting from specified \p Entry.
/// It puts 'root DIE' into the worklist.
void collectRootsToKeep(CompileUnit &CU, const DWARFDebugInfoEntry *Entry);
/// Returns true if specified variable references live code section.
bool isLiveVariableEntry(CompileUnit &CU, const DWARFDebugInfoEntry *Entry);
/// Returns true if specified subprogram references live code section.
bool isLiveSubprogramEntry(CompileUnit &CU, const DWARFDebugInfoEntry *Entry);
/// Examine worklist and mark all 'root DIE's as kept.
bool markLiveRootsAsKept();
/// Mark whole DIE tree as kept recursively.
bool markDIEEntryAsKeptRec(const RootEntryTy &RootItem, CompileUnit &CU,
const DWARFDebugInfoEntry *Entry);
/// Check referenced DIEs and add them into the worklist if neccessary.
bool maybeAddReferencedRoots(const RootEntryTy &RootItem, CompileUnit &CU,
const DWARFDebugInfoEntry *Entry);
/// Add 'root DIE' into the worklist.
void addItemToWorklist(CompileUnit &CU, const DWARFDebugInfoEntry *Entry);
/// Set kind of placement(whether it goes into type table, plain dwarf or
/// both) for the specified die \p DieIdx.
void setDIEPlacementAndTypename(CompileUnit::DIEInfo &Info);
/// Flag indicating whether liveness information should be examined.
bool TrackLiveness = false;
/// List of CU, Entry pairs which are 'root DIE's.
RootEntriesListTy RootEntriesWorkList;
/// Link context for the analyzed CU.
DWARFLinkerImpl::LinkContext &Context;
} // end namespace dwarflinker_parallel
} // end namespace llvm