1 //===-- AMDGPUAnnotateKernelFeaturesPass.cpp ------------------------------===//
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 This pass adds target attributes to functions which use intrinsics
11 /// which will impact calling convention lowering.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "AMDGPU.h"
16 #include "llvm/IR/Instructions.h"
17 #include "llvm/IR/Module.h"
18 
19 #define DEBUG_TYPE "amdgpu-annotate-kernel-features"
20 
21 using namespace llvm;
22 
23 namespace {
24 
25 class AMDGPUAnnotateKernelFeatures : public ModulePass {
26 private:
27   void addAttrToCallers(Function *Intrin, StringRef AttrName);
28   bool addAttrsForIntrinsics(Module &M, ArrayRef<StringRef[2]>);
29 
30 public:
31   static char ID;
32 
AMDGPUAnnotateKernelFeatures()33   AMDGPUAnnotateKernelFeatures() : ModulePass(ID) { }
34   bool runOnModule(Module &M) override;
getPassName() const35   const char *getPassName() const override {
36     return "AMDGPU Annotate Kernel Features";
37   }
38 
getAnalysisUsage(AnalysisUsage & AU) const39   void getAnalysisUsage(AnalysisUsage &AU) const override {
40     AU.setPreservesAll();
41     ModulePass::getAnalysisUsage(AU);
42   }
43 };
44 
45 }
46 
47 char AMDGPUAnnotateKernelFeatures::ID = 0;
48 
49 char &llvm::AMDGPUAnnotateKernelFeaturesID = AMDGPUAnnotateKernelFeatures::ID;
50 
51 
52 INITIALIZE_PASS_BEGIN(AMDGPUAnnotateKernelFeatures, DEBUG_TYPE,
53                       "Add AMDGPU function attributes", false, false)
54 INITIALIZE_PASS_END(AMDGPUAnnotateKernelFeatures, DEBUG_TYPE,
55                     "Add AMDGPU function attributes", false, false)
56 
57 
addAttrToCallers(Function * Intrin,StringRef AttrName)58 void AMDGPUAnnotateKernelFeatures::addAttrToCallers(Function *Intrin,
59                                                     StringRef AttrName) {
60   SmallPtrSet<Function *, 4> SeenFuncs;
61 
62   for (User *U : Intrin->users()) {
63     // CallInst is the only valid user for an intrinsic.
64     CallInst *CI = cast<CallInst>(U);
65 
66     Function *CallingFunction = CI->getParent()->getParent();
67     if (SeenFuncs.insert(CallingFunction).second)
68       CallingFunction->addFnAttr(AttrName);
69   }
70 }
71 
addAttrsForIntrinsics(Module & M,ArrayRef<StringRef[2]> IntrinsicToAttr)72 bool AMDGPUAnnotateKernelFeatures::addAttrsForIntrinsics(
73   Module &M,
74   ArrayRef<StringRef[2]> IntrinsicToAttr) {
75   bool Changed = false;
76 
77   for (const StringRef *Arr  : IntrinsicToAttr) {
78     if (Function *Fn = M.getFunction(Arr[0])) {
79       addAttrToCallers(Fn, Arr[1]);
80       Changed = true;
81     }
82   }
83 
84   return Changed;
85 }
86 
runOnModule(Module & M)87 bool AMDGPUAnnotateKernelFeatures::runOnModule(Module &M) {
88   Triple TT(M.getTargetTriple());
89 
90   static const StringRef IntrinsicToAttr[][2] = {
91     // .x omitted
92     { "llvm.r600.read.tgid.y", "amdgpu-work-group-id-y" },
93     { "llvm.r600.read.tgid.z", "amdgpu-work-group-id-z" },
94 
95     // .x omitted
96     { "llvm.r600.read.tidig.y", "amdgpu-work-item-id-y" },
97     { "llvm.r600.read.tidig.z", "amdgpu-work-item-id-z" }
98 
99   };
100 
101   static const StringRef HSAIntrinsicToAttr[][2] = {
102     { "llvm.r600.read.local.size.x", "amdgpu-dispatch-ptr" },
103     { "llvm.r600.read.local.size.y", "amdgpu-dispatch-ptr" },
104     { "llvm.r600.read.local.size.z", "amdgpu-dispatch-ptr" },
105 
106     { "llvm.r600.read.global.size.x", "amdgpu-dispatch-ptr" },
107     { "llvm.r600.read.global.size.y", "amdgpu-dispatch-ptr" },
108     { "llvm.r600.read.global.size.z", "amdgpu-dispatch-ptr" },
109     { "llvm.amdgcn.dispatch.ptr",     "amdgpu-dispatch-ptr" }
110   };
111 
112   // TODO: Intrinsics that require queue ptr.
113 
114   // We do not need to note the x workitem or workgroup id because they are
115   // always initialized.
116 
117   bool Changed = addAttrsForIntrinsics(M, IntrinsicToAttr);
118   if (TT.getOS() == Triple::AMDHSA)
119     Changed |= addAttrsForIntrinsics(M, HSAIntrinsicToAttr);
120 
121   return Changed;
122 }
123 
createAMDGPUAnnotateKernelFeaturesPass()124 ModulePass *llvm::createAMDGPUAnnotateKernelFeaturesPass() {
125   return new AMDGPUAnnotateKernelFeatures();
126 }
127