llvm/llvm/lib/Transforms/IPO/Internalize.cpp

//===-- Internalize.cpp - Mark functions internal -------------------------===//
//
// 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 pass loops over all of the functions and variables in the input module.
// If the function or variable does not need to be preserved according to the
// client supplied callback, it is marked as internal.
//
// This transformation would not be legal in a regular compilation, but it gets
// extra information from the linker about what is safe.
//
// For example: Internalizing a function with external linkage. Only if we are
// told it is only used from within this module, it is safe to do it.
//
//===----------------------------------------------------------------------===//

#include "llvm/Transforms/IPO/Internalize.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/GlobPattern.h"
#include "llvm/Support/LineIterator.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TargetParser/Triple.h"
#include "llvm/Transforms/IPO.h"
usingnamespacellvm;

#define DEBUG_TYPE …

STATISTIC(NumAliases, "Number of aliases internalized");
STATISTIC(NumFunctions, "Number of functions internalized");
STATISTIC(NumGlobals, "Number of global vars internalized");

// APIFile - A file which contains a list of symbol glob patterns that should
// not be marked external.
static cl::opt<std::string>
    APIFile("internalize-public-api-file", cl::value_desc("filename"),
            cl::desc("A file containing list of symbol names to preserve"));

// APIList - A list of symbol glob patterns that should not be marked internal.
static cl::list<std::string>
    APIList("internalize-public-api-list", cl::value_desc("list"),
            cl::desc("A list of symbol names to preserve"), cl::CommaSeparated);

namespace {
// Helper to load an API list to preserve from file and expose it as a functor
// for internalization.
class PreserveAPIList { … };
} // end anonymous namespace

bool InternalizePass::shouldPreserveGV(const GlobalValue &GV) { … }

bool InternalizePass::maybeInternalize(
    GlobalValue &GV, DenseMap<const Comdat *, ComdatInfo> &ComdatMap) { … }

// If GV is part of a comdat and is externally visible, update the comdat size
// and keep track of its comdat so that we don't internalize any of its members.
void InternalizePass::checkComdat(
    GlobalValue &GV, DenseMap<const Comdat *, ComdatInfo> &ComdatMap) { … }

bool InternalizePass::internalizeModule(Module &M) { … }

InternalizePass::InternalizePass() : … { … }

PreservedAnalyses InternalizePass::run(Module &M, ModuleAnalysisManager &AM) { … }