1 //===-- GCRootLowering.cpp - Garbage collection infrastructure ------------===//
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
11 //===----------------------------------------------------------------------===//
35 /// frontend, but the old API made this non-obvious, so we do a potentially
41 /// LowerIntrinsics - This pass rewrites calls to the llvm.gcread or
50   StringRef getPassName() const override;
51   void getAnalysisUsage(AnalysisUsage &AU) const override;
53   bool doInitialization(Module &M) override;
54   bool runOnFunction(Function &F) override;
57 /// GCMachineCodeAnalysis - This is a target-independent pass over the machine
76   void getAnalysisUsage(AnalysisUsage &AU) const override;
78   bool runOnMachineFunction(MachineFunction &MF) override;
98 // -----------------------------------------------------------------------------
100 INITIALIZE_PASS_BEGIN(LowerIntrinsics, "gc-lowering", "GC Lowering", false,
103 INITIALIZE_PASS_END(LowerIntrinsics, "gc-lowering", "GC Lowering", false, false)  in INITIALIZE_PASS_DEPENDENCY()
124 /// doInitialization - If this module uses the GC intrinsics, find them now.
130       MI->getFunctionInfo(F); // Instantiate the GC strategy.  in doInitialization()
135 /// CouldBecomeSafePoint - Predicate to conservatively determine whether the
141   //   - call, invoke (AfterCall, BeforeCall)  in CouldBecomeSafePoint()
142   //   - phis (Loops)  in CouldBecomeSafePoint()
143   //   - invoke, ret, unwind (Exit)  in CouldBecomeSafePoint()
146   // libcalls upon lowering (e.g., div i64 on a 32-bit platform), so instead  in CouldBecomeSafePoint()
155     if (Function *F = CI->getCalledFunction())  in CouldBecomeSafePoint()
156       if (Intrinsic::ID IID = F->getIntrinsicID())  in CouldBecomeSafePoint()
174               dyn_cast<AllocaInst>(SI->getOperand(1)->stripPointerCasts()))  in InsertRootInitializers()
183           ConstantPointerNull::get(cast<PointerType>(Root->getAllocatedType())),  in InsertRootInitializers()
184           Root, std::next(Root->getIterator()));  in InsertRootInitializers()
191 /// runOnFunction - Replace gcread/gcwrite intrinsics with loads and stores.
214       Function *F = CI->getCalledFunction();  in DoLowering()
215       switch (F->getIntrinsicID()) {  in DoLowering()
219         Value *St = new StoreInst(CI->getArgOperand(0), CI->getArgOperand(2),  in DoLowering()
220                                   CI->getIterator());  in DoLowering()
221         CI->replaceAllUsesWith(St);  in DoLowering()
222         CI->eraseFromParent();  in DoLowering()
228         Value *Ld = new LoadInst(CI->getType(), CI->getArgOperand(1), "",  in DoLowering()
229                                  CI->getIterator());  in DoLowering()
230         Ld->takeName(CI);  in DoLowering()
231         CI->replaceAllUsesWith(Ld);  in DoLowering()
232         CI->eraseFromParent();  in DoLowering()
240             cast<AllocaInst>(CI->getArgOperand(0)->stripPointerCasts()));  in DoLowering()
252 // -----------------------------------------------------------------------------
257 INITIALIZE_PASS(GCMachineCodeAnalysis, "gc-analysis",
271   MCSymbol *Label = MBB.getParent()->getContext().createTempSymbol();  in InsertLabel()
272   BuildMI(MBB, MI, DL, TII->get(TargetOpcode::GC_LABEL)).addSym(Label);  in InsertLabel()
282   MCSymbol *Label = InsertLabel(*CI->getParent(), RAI, CI->getDebugLoc());  in VisitCallPoint()
283   FI->addSafePoint(Label, CI->getDebugLoc());  in VisitCallPoint()
304   for (GCFunctionInfo::roots_iterator RI = FI->roots_begin();  in FindStackOffsets()  local
305        RI != FI->roots_end();) {  in FindStackOffsets()
307     if (MF.getFrameInfo().isDeadObjectIndex(RI->Num)) {  in FindStackOffsets()
308       RI = FI->removeStackRoot(RI);  in FindStackOffsets()
312       auto FrameOffset = TFI->getFrameIndexReference(MF, RI->Num, FrameReg);  in FindStackOffsets()
315       RI->StackOffset = FrameOffset.getFixed();  in FindStackOffsets()
316       ++RI;  in FindStackOffsets()
334       MFI.hasVarSizedObjects() || RegInfo->hasStackRealignment(MF);  in runOnMachineFunction()
335   FI->setFrameSize(DynamicFrameSize ? UINT64_MAX : MFI.getStackSize());  in runOnMachineFunction()
338   if (FI->getStrategy().needsSafePoints())  in runOnMachineFunction()