1//===- DXILFinalizeLinkage.cpp - Finalize linkage of functions ------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "DXILFinalizeLinkage.h"
10#include "DirectX.h"
11#include "llvm/IR/Function.h"
12#include "llvm/IR/GlobalValue.h"
13#include "llvm/IR/Metadata.h"
14#include "llvm/IR/Module.h"
15
16#define DEBUG_TYPE "dxil-finalize-linkage"
17
18using namespace llvm;
19
20static bool finalizeLinkage(Module &M) {
21 bool MadeChange = false;
22
23 // Convert private globals and external globals with no usage to internal
24 // linkage.
25 for (GlobalVariable &GV : M.globals()) {
26 GV.removeDeadConstantUsers();
27 if (GV.hasPrivateLinkage() || (GV.hasExternalLinkage() && GV.use_empty())) {
28 GV.setLinkage(GlobalValue::InternalLinkage);
29 MadeChange = true;
30 }
31 }
32
33 SmallVector<Function *> Funcs;
34
35 // Collect non-entry and non-exported functions to set to internal linkage.
36 for (Function &EF : M.functions()) {
37 if (EF.isIntrinsic())
38 continue;
39 if (EF.hasExternalLinkage() && EF.hasDefaultVisibility())
40 continue;
41 if (EF.hasFnAttribute(Kind: "hlsl.shader"))
42 continue;
43 Funcs.push_back(Elt: &EF);
44 }
45
46 for (Function *F : Funcs) {
47 if (F->getLinkage() == GlobalValue::ExternalLinkage) {
48 F->setLinkage(GlobalValue::InternalLinkage);
49 MadeChange = true;
50 }
51 if (F->isDefTriviallyDead()) {
52 M.getFunctionList().erase(IT: F);
53 MadeChange = true;
54 }
55 }
56
57 return MadeChange;
58}
59
60PreservedAnalyses DXILFinalizeLinkage::run(Module &M,
61 ModuleAnalysisManager &AM) {
62 if (finalizeLinkage(M))
63 return PreservedAnalyses::none();
64 return PreservedAnalyses::all();
65}
66
67bool DXILFinalizeLinkageLegacy::runOnModule(Module &M) {
68 return finalizeLinkage(M);
69}
70
71char DXILFinalizeLinkageLegacy::ID = 0;
72
73INITIALIZE_PASS_BEGIN(DXILFinalizeLinkageLegacy, DEBUG_TYPE,
74 "DXIL Finalize Linkage", false, false)
75INITIALIZE_PASS_END(DXILFinalizeLinkageLegacy, DEBUG_TYPE,
76 "DXIL Finalize Linkage", false, false)
77
78ModulePass *llvm::createDXILFinalizeLinkageLegacyPass() {
79 return new DXILFinalizeLinkageLegacy();
80}
81