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 "AMDGPUCtorDtorLowering.h"
14 #include "AMDGPU.h"
15 #include "llvm/IR/Constants.h"
16 #include "llvm/IR/Function.h"
17 #include "llvm/IR/GlobalVariable.h"
18 #include "llvm/IR/IRBuilder.h"
19 #include "llvm/IR/Module.h"
20 #include "llvm/IR/Value.h"
21 #include "llvm/Pass.h"
22 #include "llvm/Transforms/Utils/ModuleUtils.h"
23
24 using namespace llvm;
25
26 #define DEBUG_TYPE "amdgpu-lower-ctor-dtor"
27
28 namespace {
29
createInitOrFiniKernelFunction(Module & M,bool IsCtor)30 static Function *createInitOrFiniKernelFunction(Module &M, bool IsCtor) {
31 StringRef InitOrFiniKernelName = "amdgcn.device.init";
32 if (!IsCtor)
33 InitOrFiniKernelName = "amdgcn.device.fini";
34
35 Function *InitOrFiniKernel = Function::createWithDefaultAttr(
36 FunctionType::get(Type::getVoidTy(M.getContext()), false),
37 GlobalValue::ExternalLinkage, 0, InitOrFiniKernelName, &M);
38 BasicBlock *InitOrFiniKernelBB =
39 BasicBlock::Create(M.getContext(), "", InitOrFiniKernel);
40 ReturnInst::Create(M.getContext(), InitOrFiniKernelBB);
41
42 InitOrFiniKernel->setCallingConv(CallingConv::AMDGPU_KERNEL);
43 if (IsCtor)
44 InitOrFiniKernel->addFnAttr("device-init");
45 else
46 InitOrFiniKernel->addFnAttr("device-fini");
47 return InitOrFiniKernel;
48 }
49
createInitOrFiniKernel(Module & M,StringRef GlobalName,bool IsCtor)50 static bool createInitOrFiniKernel(Module &M, StringRef GlobalName,
51 bool IsCtor) {
52 GlobalVariable *GV = M.getGlobalVariable(GlobalName);
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
59 Function *InitOrFiniKernel = createInitOrFiniKernelFunction(M, IsCtor);
60 IRBuilder<> IRB(InitOrFiniKernel->getEntryBlock().getTerminator());
61
62 FunctionType *ConstructorTy = InitOrFiniKernel->getFunctionType();
63
64 for (Value *V : GA->operands()) {
65 auto *CS = cast<ConstantStruct>(V);
66 IRB.CreateCall(ConstructorTy, CS->getOperand(1));
67 }
68
69 appendToUsed(M, {InitOrFiniKernel});
70
71 GV->eraseFromParent();
72 return true;
73 }
74
lowerCtorsAndDtors(Module & M)75 static bool lowerCtorsAndDtors(Module &M) {
76 bool Modified = false;
77 Modified |= createInitOrFiniKernel(M, "llvm.global_ctors", /*IsCtor =*/true);
78 Modified |= createInitOrFiniKernel(M, "llvm.global_dtors", /*IsCtor =*/false);
79 return Modified;
80 }
81
82 class AMDGPUCtorDtorLoweringLegacy final : public ModulePass {
83 public:
84 static char ID;
AMDGPUCtorDtorLoweringLegacy()85 AMDGPUCtorDtorLoweringLegacy() : ModulePass(ID) {}
runOnModule(Module & M)86 bool runOnModule(Module &M) override {
87 return lowerCtorsAndDtors(M);
88 }
89 };
90
91 } // End anonymous namespace
92
run(Module & M,ModuleAnalysisManager & AM)93 PreservedAnalyses AMDGPUCtorDtorLoweringPass::run(Module &M,
94 ModuleAnalysisManager &AM) {
95 lowerCtorsAndDtors(M);
96 return PreservedAnalyses::all();
97 }
98
99 char AMDGPUCtorDtorLoweringLegacy::ID = 0;
100 char &llvm::AMDGPUCtorDtorLoweringLegacyPassID =
101 AMDGPUCtorDtorLoweringLegacy::ID;
102 INITIALIZE_PASS(AMDGPUCtorDtorLoweringLegacy, DEBUG_TYPE,
103 "Lower ctors and dtors for AMDGPU", false, false)
104
createAMDGPUCtorDtorLoweringLegacyPass()105 ModulePass *llvm::createAMDGPUCtorDtorLoweringLegacyPass() {
106 return new AMDGPUCtorDtorLoweringLegacy();
107 }
108