SITypeRewriter.cpp revision 263508 
1//===-- SITypeRewriter.cpp - Remove unwanted types ------------------------===//
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 removes performs the following type substitution on all
12/// non-compute shaders:
13///
14/// v16i8 => i128
15///   - v16i8 is used for constant memory resource descriptors.  This type is
16///      legal for some compute APIs, and we don't want to declare it as legal
17///      in the backend, because we want the legalizer to expand all v16i8
18///      operations.
19/// v1* => *
20///   - Having v1* types complicates the legalizer and we can easily replace
21///   - them with the element type.
22//===----------------------------------------------------------------------===//
23
24#include "AMDGPU.h"
25
26#include "llvm/IR/IRBuilder.h"
27#include "llvm/InstVisitor.h"
28
29using namespace llvm;
30
31namespace {
32
33class SITypeRewriter : public FunctionPass,
34                       public InstVisitor<SITypeRewriter> {
35
36  static char ID;
37  Module *Mod;
38  Type *v16i8;
39  Type *i128;
40
41public:
42  SITypeRewriter() : FunctionPass(ID) { }
43  virtual bool doInitialization(Module &M);
44  virtual bool runOnFunction(Function &F);
45  virtual const char *getPassName() const {
46    return "SI Type Rewriter";
47  }
48  void visitLoadInst(LoadInst &I);
49  void visitCallInst(CallInst &I);
50  void visitBitCast(BitCastInst &I);
51};
52
53} // End anonymous namespace
54
55char SITypeRewriter::ID = 0;
56
57bool SITypeRewriter::doInitialization(Module &M) {
58  Mod = &M;
59  v16i8 = VectorType::get(Type::getInt8Ty(M.getContext()), 16);
60  i128 = Type::getIntNTy(M.getContext(), 128);
61  return false;
62}
63
64bool SITypeRewriter::runOnFunction(Function &F) {
65  AttributeSet Set = F.getAttributes();
66  Attribute A = Set.getAttribute(AttributeSet::FunctionIndex, "ShaderType");
67
68  unsigned ShaderType = ShaderType::COMPUTE;
69  if (A.isStringAttribute()) {
70    StringRef Str = A.getValueAsString();
71    Str.getAsInteger(0, ShaderType);
72  }
73  if (ShaderType != ShaderType::COMPUTE) {
74    visit(F);
75  }
76
77  visit(F);
78
79  return false;
80}
81
82void SITypeRewriter::visitLoadInst(LoadInst &I) {
83  Value *Ptr = I.getPointerOperand();
84  Type *PtrTy = Ptr->getType();
85  Type *ElemTy = PtrTy->getPointerElementType();
86  IRBuilder<> Builder(&I);
87  if (ElemTy == v16i8)  {
88    Value *BitCast = Builder.CreateBitCast(Ptr, Type::getIntNPtrTy(I.getContext(), 128, 2));
89    LoadInst *Load = Builder.CreateLoad(BitCast);
90    SmallVector <std::pair<unsigned, MDNode*>, 8> MD;
91    I.getAllMetadataOtherThanDebugLoc(MD);
92    for (unsigned i = 0, e = MD.size(); i != e; ++i) {
93      Load->setMetadata(MD[i].first, MD[i].second);
94    }
95    Value *BitCastLoad = Builder.CreateBitCast(Load, I.getType());
96    I.replaceAllUsesWith(BitCastLoad);
97    I.eraseFromParent();
98  }
99}
100
101void SITypeRewriter::visitCallInst(CallInst &I) {
102  IRBuilder<> Builder(&I);
103  SmallVector <Value*, 8> Args;
104  SmallVector <Type*, 8> Types;
105  bool NeedToReplace = false;
106  Function *F = I.getCalledFunction();
107  std::string Name = F->getName().str();
108  for (unsigned i = 0, e = I.getNumArgOperands(); i != e; ++i) {
109    Value *Arg = I.getArgOperand(i);
110    if (Arg->getType() == v16i8) {
111      Args.push_back(Builder.CreateBitCast(Arg, i128));
112      Types.push_back(i128);
113      NeedToReplace = true;
114      Name = Name + ".i128";
115    } else if (Arg->getType()->isVectorTy() &&
116               Arg->getType()->getVectorNumElements() == 1 &&
117               Arg->getType()->getVectorElementType() ==
118                                              Type::getInt32Ty(I.getContext())){
119      Type *ElementTy = Arg->getType()->getVectorElementType();
120      std::string TypeName = "i32";
121      InsertElementInst *Def = dyn_cast<InsertElementInst>(Arg);
122      assert(Def);
123      Args.push_back(Def->getOperand(1));
124      Types.push_back(ElementTy);
125      std::string VecTypeName = "v1" + TypeName;
126      Name = Name.replace(Name.find(VecTypeName), VecTypeName.length(), TypeName);
127      NeedToReplace = true;
128    } else {
129      Args.push_back(Arg);
130      Types.push_back(Arg->getType());
131    }
132  }
133
134  if (!NeedToReplace) {
135    return;
136  }
137  Function *NewF = Mod->getFunction(Name);
138  if (!NewF) {
139    NewF = Function::Create(FunctionType::get(F->getReturnType(), Types, false), GlobalValue::ExternalLinkage, Name, Mod);
140    NewF->setAttributes(F->getAttributes());
141  }
142  I.replaceAllUsesWith(Builder.CreateCall(NewF, Args));
143  I.eraseFromParent();
144}
145
146void SITypeRewriter::visitBitCast(BitCastInst &I) {
147  IRBuilder<> Builder(&I);
148  if (I.getDestTy() != i128) {
149    return;
150  }
151
152  if (BitCastInst *Op = dyn_cast<BitCastInst>(I.getOperand(0))) {
153    if (Op->getSrcTy() == i128) {
154      I.replaceAllUsesWith(Op->getOperand(0));
155      I.eraseFromParent();
156    }
157  }
158}
159
160FunctionPass *llvm::createSITypeRewriter() {
161  return new SITypeRewriter();
162}
163