1 //===- DXILOpLower.cpp - Lowering LLVM intrinsic to DIXLOp function -------===//
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 /// \file This file contains passes and utilities to lower llvm intrinsic call
10 /// to DXILOp function call.
11 //===----------------------------------------------------------------------===//
12 
13 #include "DXILConstants.h"
14 #include "DXILOpBuilder.h"
15 #include "DirectX.h"
16 #include "llvm/ADT/SmallVector.h"
17 #include "llvm/CodeGen/Passes.h"
18 #include "llvm/IR/IRBuilder.h"
19 #include "llvm/IR/Instruction.h"
20 #include "llvm/IR/Intrinsics.h"
21 #include "llvm/IR/IntrinsicsDirectX.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/IR/PassManager.h"
24 #include "llvm/Pass.h"
25 #include "llvm/Support/ErrorHandling.h"
26 
27 #define DEBUG_TYPE "dxil-op-lower"
28 
29 using namespace llvm;
30 using namespace llvm::DXIL;
31 
32 static void lowerIntrinsic(DXIL::OpCode DXILOp, Function &F, Module &M) {
33   IRBuilder<> B(M.getContext());
34   Value *DXILOpArg = B.getInt32(static_cast<unsigned>(DXILOp));
35   DXILOpBuilder DXILB(M, B);
36   Type *OverloadTy =
37       DXILB.getOverloadTy(DXILOp, F.getFunctionType(), /*NoOpCodeParam*/ true);
38   for (User *U : make_early_inc_range(F.users())) {
39     CallInst *CI = dyn_cast<CallInst>(U);
40     if (!CI)
41       continue;
42 
43     SmallVector<Value *> Args;
44     Args.emplace_back(DXILOpArg);
45     Args.append(CI->arg_begin(), CI->arg_end());
46     B.SetInsertPoint(CI);
47     CallInst *DXILCI = DXILB.createDXILOpCall(DXILOp, OverloadTy, CI->args());
48 
49     CI->replaceAllUsesWith(DXILCI);
50     CI->eraseFromParent();
51   }
52   if (F.user_empty())
53     F.eraseFromParent();
54 }
55 
56 static bool lowerIntrinsics(Module &M) {
57   bool Updated = false;
58 
59 #define DXIL_OP_INTRINSIC_MAP
60 #include "DXILOperation.inc"
61 #undef DXIL_OP_INTRINSIC_MAP
62 
63   for (Function &F : make_early_inc_range(M.functions())) {
64     if (!F.isDeclaration())
65       continue;
66     Intrinsic::ID ID = F.getIntrinsicID();
67     if (ID == Intrinsic::not_intrinsic)
68       continue;
69     auto LowerIt = LowerMap.find(ID);
70     if (LowerIt == LowerMap.end())
71       continue;
72     lowerIntrinsic(LowerIt->second, F, M);
73     Updated = true;
74   }
75   return Updated;
76 }
77 
78 namespace {
79 /// A pass that transforms external global definitions into declarations.
80 class DXILOpLowering : public PassInfoMixin<DXILOpLowering> {
81 public:
82   PreservedAnalyses run(Module &M, ModuleAnalysisManager &) {
83     if (lowerIntrinsics(M))
84       return PreservedAnalyses::none();
85     return PreservedAnalyses::all();
86   }
87 };
88 } // namespace
89 
90 namespace {
91 class DXILOpLoweringLegacy : public ModulePass {
92 public:
93   bool runOnModule(Module &M) override { return lowerIntrinsics(M); }
94   StringRef getPassName() const override { return "DXIL Op Lowering"; }
95   DXILOpLoweringLegacy() : ModulePass(ID) {}
96 
97   static char ID; // Pass identification.
98 };
99 char DXILOpLoweringLegacy::ID = 0;
100 
101 } // end anonymous namespace
102 
103 INITIALIZE_PASS_BEGIN(DXILOpLoweringLegacy, DEBUG_TYPE, "DXIL Op Lowering",
104                       false, false)
105 INITIALIZE_PASS_END(DXILOpLoweringLegacy, DEBUG_TYPE, "DXIL Op Lowering", false,
106                     false)
107 
108 ModulePass *llvm::createDXILOpLoweringLegacyPass() {
109   return new DXILOpLoweringLegacy();
110 }
111