1 //===- CoroCleanup.cpp - Coroutine Cleanup Pass ---------------------------===//
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 // This pass lowers all remaining coroutine intrinsics.
10 //===----------------------------------------------------------------------===//
11
12 #include "CoroInternal.h"
13 #include "llvm/IR/IRBuilder.h"
14 #include "llvm/IR/InstIterator.h"
15 #include "llvm/IR/LegacyPassManager.h"
16 #include "llvm/Pass.h"
17 #include "llvm/Transforms/Scalar.h"
18
19 using namespace llvm;
20
21 #define DEBUG_TYPE "coro-cleanup"
22
23 namespace {
24 // Created on demand if CoroCleanup pass has work to do.
25 struct Lowerer : coro::LowererBase {
26 IRBuilder<> Builder;
Lowerer__anon5db007860111::Lowerer27 Lowerer(Module &M) : LowererBase(M), Builder(Context) {}
28 bool lowerRemainingCoroIntrinsics(Function &F);
29 };
30 }
31
simplifyCFG(Function & F)32 static void simplifyCFG(Function &F) {
33 llvm::legacy::FunctionPassManager FPM(F.getParent());
34 FPM.add(createCFGSimplificationPass());
35
36 FPM.doInitialization();
37 FPM.run(F);
38 FPM.doFinalization();
39 }
40
lowerSubFn(IRBuilder<> & Builder,CoroSubFnInst * SubFn)41 static void lowerSubFn(IRBuilder<> &Builder, CoroSubFnInst *SubFn) {
42 Builder.SetInsertPoint(SubFn);
43 Value *FrameRaw = SubFn->getFrame();
44 int Index = SubFn->getIndex();
45
46 auto *FrameTy = StructType::get(
47 SubFn->getContext(), {Builder.getInt8PtrTy(), Builder.getInt8PtrTy()});
48 PointerType *FramePtrTy = FrameTy->getPointerTo();
49
50 Builder.SetInsertPoint(SubFn);
51 auto *FramePtr = Builder.CreateBitCast(FrameRaw, FramePtrTy);
52 auto *Gep = Builder.CreateConstInBoundsGEP2_32(FrameTy, FramePtr, 0, Index);
53 auto *Load = Builder.CreateLoad(Gep);
54
55 SubFn->replaceAllUsesWith(Load);
56 }
57
lowerRemainingCoroIntrinsics(Function & F)58 bool Lowerer::lowerRemainingCoroIntrinsics(Function &F) {
59 bool Changed = false;
60
61 for (auto IB = inst_begin(F), E = inst_end(F); IB != E;) {
62 Instruction &I = *IB++;
63 if (auto *II = dyn_cast<IntrinsicInst>(&I)) {
64 switch (II->getIntrinsicID()) {
65 default:
66 continue;
67 case Intrinsic::coro_begin:
68 II->replaceAllUsesWith(II->getArgOperand(1));
69 break;
70 case Intrinsic::coro_free:
71 II->replaceAllUsesWith(II->getArgOperand(1));
72 break;
73 case Intrinsic::coro_alloc:
74 II->replaceAllUsesWith(ConstantInt::getTrue(Context));
75 break;
76 case Intrinsic::coro_id:
77 II->replaceAllUsesWith(ConstantTokenNone::get(Context));
78 break;
79 case Intrinsic::coro_subfn_addr:
80 lowerSubFn(Builder, cast<CoroSubFnInst>(II));
81 break;
82 }
83 II->eraseFromParent();
84 Changed = true;
85 }
86 }
87
88 if (Changed) {
89 // After replacement were made we can cleanup the function body a little.
90 simplifyCFG(F);
91 }
92 return Changed;
93 }
94
95 //===----------------------------------------------------------------------===//
96 // Top Level Driver
97 //===----------------------------------------------------------------------===//
98
99 namespace {
100
101 struct CoroCleanup : FunctionPass {
102 static char ID; // Pass identification, replacement for typeid
103
CoroCleanup__anon5db007860211::CoroCleanup104 CoroCleanup() : FunctionPass(ID) {
105 initializeCoroCleanupPass(*PassRegistry::getPassRegistry());
106 }
107
108 std::unique_ptr<Lowerer> L;
109
110 // This pass has work to do only if we find intrinsics we are going to lower
111 // in the module.
doInitialization__anon5db007860211::CoroCleanup112 bool doInitialization(Module &M) override {
113 if (coro::declaresIntrinsics(M, {"llvm.coro.alloc", "llvm.coro.begin",
114 "llvm.coro.subfn.addr", "llvm.coro.free",
115 "llvm.coro.id"}))
116 L = llvm::make_unique<Lowerer>(M);
117 return false;
118 }
119
runOnFunction__anon5db007860211::CoroCleanup120 bool runOnFunction(Function &F) override {
121 if (L)
122 return L->lowerRemainingCoroIntrinsics(F);
123 return false;
124 }
getAnalysisUsage__anon5db007860211::CoroCleanup125 void getAnalysisUsage(AnalysisUsage &AU) const override {
126 if (!L)
127 AU.setPreservesAll();
128 }
getPassName__anon5db007860211::CoroCleanup129 StringRef getPassName() const override { return "Coroutine Cleanup"; }
130 };
131 }
132
133 char CoroCleanup::ID = 0;
134 INITIALIZE_PASS(CoroCleanup, "coro-cleanup",
135 "Lower all coroutine related intrinsics", false, false)
136
createCoroCleanupPass()137 Pass *llvm::createCoroCleanupPass() { return new CoroCleanup(); }
138