1 //===-- AMDGPUCtorDtorLowering.cpp - Handle global ctors and dtors --------===//
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
10 /// This pass creates a unified init and fini kernel with the required metadata
11 //===----------------------------------------------------------------------===//
12
13 #include "AMDGPU.h"
14 #include "llvm/IR/Constants.h"
15 #include "llvm/IR/Function.h"
16 #include "llvm/IR/GlobalVariable.h"
17 #include "llvm/IR/IRBuilder.h"
18 #include "llvm/IR/Module.h"
19 #include "llvm/IR/Value.h"
20 #include "llvm/Pass.h"
21 #include "llvm/Transforms/Utils/ModuleUtils.h"
22
23 using namespace llvm;
24
25 #define DEBUG_TYPE "amdgpu-lower-ctor-dtor"
26
27 namespace {
28 class AMDGPUCtorDtorLowering final : public ModulePass {
29 bool runOnModule(Module &M) override;
30
31 public:
createInitOrFiniKernelFunction(Module & M,bool IsCtor)32 Function *createInitOrFiniKernelFunction(Module &M, bool IsCtor) {
33 StringRef InitOrFiniKernelName = "amdgcn.device.init";
34 if (!IsCtor)
35 InitOrFiniKernelName = "amdgcn.device.fini";
36
37 Function *InitOrFiniKernel = Function::createWithDefaultAttr(
38 FunctionType::get(Type::getVoidTy(M.getContext()), false),
39 GlobalValue::ExternalLinkage, 0, InitOrFiniKernelName, &M);
40 BasicBlock *InitOrFiniKernelBB =
41 BasicBlock::Create(M.getContext(), "", InitOrFiniKernel);
42 ReturnInst::Create(M.getContext(), InitOrFiniKernelBB);
43
44 InitOrFiniKernel->setCallingConv(CallingConv::AMDGPU_KERNEL);
45 if (IsCtor)
46 InitOrFiniKernel->addFnAttr("device-init");
47 else
48 InitOrFiniKernel->addFnAttr("device-fini");
49 return InitOrFiniKernel;
50 }
51
createInitOrFiniKernel(Module & M,GlobalVariable * GV,bool IsCtor)52 bool createInitOrFiniKernel(Module &M, GlobalVariable *GV, bool IsCtor) {
53 if (!GV || !GV->hasInitializer())
54 return false;
55 ConstantArray *GA = dyn_cast<ConstantArray>(GV->getInitializer());
56 if (!GA || GA->getNumOperands() == 0)
57 return false;
58 Function *InitOrFiniKernel = createInitOrFiniKernelFunction(M, IsCtor);
59 IRBuilder<> IRB(InitOrFiniKernel->getEntryBlock().getTerminator());
60 for (Value *V : GA->operands()) {
61 auto *CS = cast<ConstantStruct>(V);
62 if (Function *F = dyn_cast<Function>(CS->getOperand(1))) {
63 FunctionCallee Ctor =
64 M.getOrInsertFunction(F->getName(), IRB.getVoidTy());
65 IRB.CreateCall(Ctor);
66 }
67 }
68 appendToUsed(M, {InitOrFiniKernel});
69 return true;
70 }
71
72 static char ID;
AMDGPUCtorDtorLowering()73 AMDGPUCtorDtorLowering() : ModulePass(ID) {}
74 };
75 } // End anonymous namespace
76
77 char AMDGPUCtorDtorLowering::ID = 0;
78 char &llvm::AMDGPUCtorDtorLoweringID = AMDGPUCtorDtorLowering::ID;
79 INITIALIZE_PASS(AMDGPUCtorDtorLowering, DEBUG_TYPE,
80 "Lower ctors and dtors for AMDGPU", false, false)
81
createAMDGPUCtorDtorLoweringPass()82 ModulePass *llvm::createAMDGPUCtorDtorLoweringPass() {
83 return new AMDGPUCtorDtorLowering();
84 }
85
runOnModule(Module & M)86 bool AMDGPUCtorDtorLowering::runOnModule(Module &M) {
87 bool Modified = false;
88 Modified |=
89 createInitOrFiniKernel(M, M.getGlobalVariable("llvm.global_ctors"),
90 /*IsCtor =*/true);
91 Modified |=
92 createInitOrFiniKernel(M, M.getGlobalVariable("llvm.global_dtors"),
93 /*IsCtor =*/false);
94 return Modified;
95 }
96