1 //===-- AMDGPUAlwaysInlinePass.cpp - Promote Allocas ----------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 /// \file
11 /// This pass marks all internal functions as always_inline and creates
12 /// duplicates of all other functions a marks the duplicates as always_inline.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "AMDGPU.h"
17 #include "llvm/IR/Module.h"
18 #include "llvm/Transforms/Utils/Cloning.h"
19 
20 using namespace llvm;
21 
22 namespace {
23 
24 class AMDGPUAlwaysInline : public ModulePass {
25   static char ID;
26 
27 public:
28   AMDGPUAlwaysInline() : ModulePass(ID) { }
29   bool runOnModule(Module &M) override;
30   StringRef getPassName() const override { return "AMDGPU Always Inline Pass"; }
31 };
32 
33 } // End anonymous namespace
34 
35 char AMDGPUAlwaysInline::ID = 0;
36 
37 bool AMDGPUAlwaysInline::runOnModule(Module &M) {
38   std::vector<GlobalAlias*> AliasesToRemove;
39   std::vector<Function *> FuncsToClone;
40 
41   for (GlobalAlias &A : M.aliases()) {
42     if (Function* F = dyn_cast<Function>(A.getAliasee())) {
43       A.replaceAllUsesWith(F);
44       AliasesToRemove.push_back(&A);
45     }
46   }
47 
48   for (GlobalAlias* A : AliasesToRemove) {
49     A->eraseFromParent();
50   }
51 
52   for (Function &F : M) {
53     if (!F.hasLocalLinkage() && !F.isDeclaration() && !F.use_empty() &&
54         !F.hasFnAttribute(Attribute::NoInline))
55       FuncsToClone.push_back(&F);
56   }
57 
58   for (Function *F : FuncsToClone) {
59     ValueToValueMapTy VMap;
60     Function *NewFunc = CloneFunction(F, VMap);
61     NewFunc->setLinkage(GlobalValue::InternalLinkage);
62     F->replaceAllUsesWith(NewFunc);
63   }
64 
65   for (Function &F : M) {
66     if (F.hasLocalLinkage() && !F.hasFnAttribute(Attribute::NoInline)) {
67       F.addFnAttr(Attribute::AlwaysInline);
68     }
69   }
70   return false;
71 }
72 
73 ModulePass *llvm::createAMDGPUAlwaysInlinePass() {
74   return new AMDGPUAlwaysInline();
75 }
76