llvm/llvm/lib/Transforms/IPO/ElimAvailExtern.cpp

//===- ElimAvailExtern.cpp - DCE unreachable internal functions -----------===//
//
// 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 transform is designed to eliminate available external global
// definitions from the program, turning them into declarations.
//
//===----------------------------------------------------------------------===//

#include "llvm/Transforms/IPO/ElimAvailExtern.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/CtxProfAnalysis.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Utils/GlobalStatus.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"

usingnamespacellvm;

#define DEBUG_TYPE …

cl::opt<bool> ConvertToLocal(
    "avail-extern-to-local", cl::Hidden,
    cl::desc("Convert available_externally into locals, renaming them "
             "to avoid link-time clashes."));

STATISTIC(NumRemovals, "Number of functions removed");
STATISTIC(NumConversions, "Number of functions converted");
STATISTIC(NumVariables, "Number of global variables removed");

void deleteFunction(Function &F) { … }

/// Create a copy of the thinlto import, mark it local, and redirect direct
/// calls to the copy. Only direct calls are replaced, so that e.g. indirect
/// call function pointer tests would use the global identity of the function.
///
/// Currently, Value Profiling ("VP") MD_prof data isn't updated to refer to the
/// clone's GUID (which will be different, because the name and linkage is
/// different), under the assumption that the last consumer of this data is
/// upstream the pipeline (e.g. ICP).
static void convertToLocalCopy(Module &M, Function &F) { … }

static bool eliminateAvailableExternally(Module &M, bool Convert) { … }

PreservedAnalyses
EliminateAvailableExternallyPass::run(Module &M, ModuleAnalysisManager &MAM) { … }