mirror of
https://github.com/RPCS3/llvm.git
synced 2025-05-14 09:26:22 +00:00
6b547686c5
to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351636 91177308-0d34-0410-b5e6-96231b3b80d8
102 lines
3.1 KiB
C++
102 lines
3.1 KiB
C++
//===- 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/Statistic.h"
|
|
#include "llvm/IR/Constant.h"
|
|
#include "llvm/IR/Function.h"
|
|
#include "llvm/IR/GlobalValue.h"
|
|
#include "llvm/IR/GlobalVariable.h"
|
|
#include "llvm/IR/Module.h"
|
|
#include "llvm/Pass.h"
|
|
#include "llvm/Transforms/IPO.h"
|
|
#include "llvm/Transforms/Utils/GlobalStatus.h"
|
|
|
|
using namespace llvm;
|
|
|
|
#define DEBUG_TYPE "elim-avail-extern"
|
|
|
|
STATISTIC(NumFunctions, "Number of functions removed");
|
|
STATISTIC(NumVariables, "Number of global variables removed");
|
|
|
|
static bool eliminateAvailableExternally(Module &M) {
|
|
bool Changed = false;
|
|
|
|
// Drop initializers of available externally global variables.
|
|
for (GlobalVariable &GV : M.globals()) {
|
|
if (!GV.hasAvailableExternallyLinkage())
|
|
continue;
|
|
if (GV.hasInitializer()) {
|
|
Constant *Init = GV.getInitializer();
|
|
GV.setInitializer(nullptr);
|
|
if (isSafeToDestroyConstant(Init))
|
|
Init->destroyConstant();
|
|
}
|
|
GV.removeDeadConstantUsers();
|
|
GV.setLinkage(GlobalValue::ExternalLinkage);
|
|
NumVariables++;
|
|
Changed = true;
|
|
}
|
|
|
|
// Drop the bodies of available externally functions.
|
|
for (Function &F : M) {
|
|
if (!F.hasAvailableExternallyLinkage())
|
|
continue;
|
|
if (!F.isDeclaration())
|
|
// This will set the linkage to external
|
|
F.deleteBody();
|
|
F.removeDeadConstantUsers();
|
|
NumFunctions++;
|
|
Changed = true;
|
|
}
|
|
|
|
return Changed;
|
|
}
|
|
|
|
PreservedAnalyses
|
|
EliminateAvailableExternallyPass::run(Module &M, ModuleAnalysisManager &) {
|
|
if (!eliminateAvailableExternally(M))
|
|
return PreservedAnalyses::all();
|
|
return PreservedAnalyses::none();
|
|
}
|
|
|
|
namespace {
|
|
|
|
struct EliminateAvailableExternallyLegacyPass : public ModulePass {
|
|
static char ID; // Pass identification, replacement for typeid
|
|
|
|
EliminateAvailableExternallyLegacyPass() : ModulePass(ID) {
|
|
initializeEliminateAvailableExternallyLegacyPassPass(
|
|
*PassRegistry::getPassRegistry());
|
|
}
|
|
|
|
// run - Do the EliminateAvailableExternally pass on the specified module,
|
|
// optionally updating the specified callgraph to reflect the changes.
|
|
bool runOnModule(Module &M) override {
|
|
if (skipModule(M))
|
|
return false;
|
|
return eliminateAvailableExternally(M);
|
|
}
|
|
};
|
|
|
|
} // end anonymous namespace
|
|
|
|
char EliminateAvailableExternallyLegacyPass::ID = 0;
|
|
|
|
INITIALIZE_PASS(EliminateAvailableExternallyLegacyPass, "elim-avail-extern",
|
|
"Eliminate Available Externally Globals", false, false)
|
|
|
|
ModulePass *llvm::createEliminateAvailableExternallyPass() {
|
|
return new EliminateAvailableExternallyLegacyPass();
|
|
}
|