llvm/llvm/lib/Transforms/Utils/SplitModule.cpp

//===- SplitModule.cpp - Split a module into partitions -------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file defines the function llvm::SplitModule, which splits a module
// into multiple linkable partitions. It can be used to implement parallel code
// generation for link-time optimization.
//
//===----------------------------------------------------------------------===//

#include "llvm/Transforms/Utils/SplitModule.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/EquivalenceClasses.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/IR/Comdat.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/GlobalObject.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/User.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MD5.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
#include <algorithm>
#include <cassert>
#include <iterator>
#include <memory>
#include <queue>
#include <utility>
#include <vector>

usingnamespacellvm;

#define DEBUG_TYPE …

namespace {

ClusterMapType;
ComdatMembersType;
ClusterIDMapType;

bool compareClusters(const std::pair<unsigned, unsigned> &A,
                     const std::pair<unsigned, unsigned> &B) { … }

BalancingQueueType;

} // end anonymous namespace

static void addNonConstUser(ClusterMapType &GVtoClusterMap,
                            const GlobalValue *GV, const User *U) { … }

// Adds all GlobalValue users of V to the same cluster as GV.
static void addAllGlobalValueUsers(ClusterMapType &GVtoClusterMap,
                                   const GlobalValue *GV, const Value *V) { … }

static const GlobalObject *getGVPartitioningRoot(const GlobalValue *GV) { … }

// Find partitions for module in the way that no locals need to be
// globalized.
// Try to balance pack those partitions into N files since this roughly equals
// thread balancing for the backend codegen step.
static void findPartitions(Module &M, ClusterIDMapType &ClusterIDMap,
                           unsigned N) { … }

static void externalize(GlobalValue *GV) { … }

// Returns whether GV should be in partition (0-based) I of N.
static bool isInPartition(const GlobalValue *GV, unsigned I, unsigned N) { … }

void llvm::SplitModule(
    Module &M, unsigned N,
    function_ref<void(std::unique_ptr<Module> MPart)> ModuleCallback,
    bool PreserveLocals, bool RoundRobin) { … }