| //===--------------------- NVPTXAliasAnalysis.cpp--------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| /// \file |
| /// This is the NVPTX address space based alias analysis pass. |
| //===----------------------------------------------------------------------===// |
| |
| #include "NVPTXAliasAnalysis.h" |
| #include "MCTargetDesc/NVPTXBaseInfo.h" |
| #include "NVPTX.h" |
| #include "llvm/Analysis/ValueTracking.h" |
| #include "llvm/IR/CallingConv.h" |
| #include "llvm/IR/Instructions.h" |
| |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "NVPTX-aa" |
| |
| AnalysisKey NVPTXAA::Key; |
| |
| char NVPTXAAWrapperPass::ID = 0; |
| char NVPTXExternalAAWrapper::ID = 0; |
| |
| INITIALIZE_PASS(NVPTXAAWrapperPass, "nvptx-aa", |
| "NVPTX Address space based Alias Analysis", false, true) |
| |
| INITIALIZE_PASS(NVPTXExternalAAWrapper, "nvptx-aa-wrapper", |
| "NVPTX Address space based Alias Analysis Wrapper", false, true) |
| |
| ImmutablePass *llvm::createNVPTXAAWrapperPass() { |
| return new NVPTXAAWrapperPass(); |
| } |
| |
| ImmutablePass *llvm::createNVPTXExternalAAWrapperPass() { |
| return new NVPTXExternalAAWrapper(); |
| } |
| |
| NVPTXAAWrapperPass::NVPTXAAWrapperPass() : ImmutablePass(ID) { |
| initializeNVPTXAAWrapperPassPass(*PassRegistry::getPassRegistry()); |
| } |
| |
| void NVPTXAAWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const { |
| AU.setPreservesAll(); |
| } |
| |
| static AliasResult::Kind getAliasResult(unsigned AS1, unsigned AS2) { |
| if ((AS1 == ADDRESS_SPACE_GENERIC) || (AS2 == ADDRESS_SPACE_GENERIC)) |
| return AliasResult::MayAlias; |
| |
| // PTX s6.4.1.1. Generic Addressing: |
| // A generic address maps to global memory unless it falls within |
| // the window for const, local, or shared memory. The Kernel |
| // Function Parameters (.param) window is contained within the |
| // .global window. |
| // |
| // Therefore a global pointer may alias with a param pointer on some |
| // GPUs via addrspacecast(param->generic->global) when cvta.param |
| // instruction is used (PTX 7.7+ and SM_70+). |
| // |
| // TODO: cvta.param is not yet supported. We need to change aliasing |
| // rules once it is added. |
| |
| return (AS1 == AS2 ? AliasResult::MayAlias : AliasResult::NoAlias); |
| } |
| |
| AliasResult NVPTXAAResult::alias(const MemoryLocation &Loc1, |
| const MemoryLocation &Loc2, AAQueryInfo &AAQI, |
| const Instruction *) { |
| unsigned AS1 = Loc1.Ptr->getType()->getPointerAddressSpace(); |
| unsigned AS2 = Loc2.Ptr->getType()->getPointerAddressSpace(); |
| |
| return getAliasResult(AS1, AS2); |
| } |
| |
| // TODO: .param address space may be writable in presence of cvta.param, but |
| // this instruction is currently not supported. NVPTXLowerArgs also does not |
| // allow any writes to .param pointers. |
| static bool isConstOrParam(unsigned AS) { |
| return AS == AddressSpace::ADDRESS_SPACE_CONST || |
| AS == AddressSpace::ADDRESS_SPACE_PARAM; |
| } |
| |
| ModRefInfo NVPTXAAResult::getModRefInfoMask(const MemoryLocation &Loc, |
| AAQueryInfo &AAQI, |
| bool IgnoreLocals) { |
| if (isConstOrParam(Loc.Ptr->getType()->getPointerAddressSpace())) |
| return ModRefInfo::NoModRef; |
| |
| const Value *Base = getUnderlyingObject(Loc.Ptr); |
| if (isConstOrParam(Base->getType()->getPointerAddressSpace())) |
| return ModRefInfo::NoModRef; |
| |
| return ModRefInfo::ModRef; |
| } |