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[SPIR-V] Add legalize-addrspace-cast pass
This commit adds a new pass in the backend which propagates the addrspace of the pointers down to the last use, making sure the addrspace remains consistent, and thus stripping any addrspacecast. This is required to lower LLVM-IR to logical SPIR-V, which does not support generic pointers. This is now required as HLSL emits several address spaces, and thus addrspacecasts in some cases: Example 1: resource access ```llvm %handle = tail call target("spirv.VulkanBuffer", ...) %rptr = @llvm.spv.resource.getpointer(%handle, ...); %cptr = addrspacecast ptr addrspace(11) %rptr to ptr %fptr = load i32, ptr %cptr ``` Example 2: object methods ```llvm define void @objectmethod(ptr %this) { } define void @foo(ptr addrspace(11) %object) { call void @objectmethod(ptr addrspacecast(addrspace(11) %object to ptr)); } ```
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‎llvm/lib/Target/SPIRV/CMakeLists.txt

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@@ -28,6 +28,7 @@ add_llvm_target(SPIRVCodeGen
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SPIRVInstructionSelector.cpp
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SPIRVStripConvergentIntrinsics.cpp
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SPIRVLegalizePointerCast.cpp
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SPIRVLegalizeAddrspaceCast.cpp
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SPIRVMergeRegionExitTargets.cpp
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SPIRVISelLowering.cpp
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SPIRVLegalizerInfo.cpp

‎llvm/lib/Target/SPIRV/SPIRV.h

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@@ -24,6 +24,7 @@ FunctionPass *createSPIRVStructurizerPass();
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FunctionPass *createSPIRVMergeRegionExitTargetsPass();
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FunctionPass *createSPIRVStripConvergenceIntrinsicsPass();
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FunctionPass *createSPIRVLegalizePointerCastPass(SPIRVTargetMachine *TM);
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FunctionPass *createSPIRVLegalizeAddrspaceCastPass(SPIRVTargetMachine *TM);
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FunctionPass *createSPIRVRegularizerPass();
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FunctionPass *createSPIRVPreLegalizerCombiner();
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FunctionPass *createSPIRVPreLegalizerPass();

‎llvm/lib/Target/SPIRV/SPIRVLegalizeAddrspaceCast.cpp

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//===-- SPIRVLegalizeAddrspaceCast.cpp ----------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "SPIRV.h"
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#include "SPIRVSubtarget.h"
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#include "SPIRVTargetMachine.h"
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#include "SPIRVUtils.h"
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#include "llvm/CodeGen/IntrinsicLowering.h"
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#include "llvm/IR/IRBuilder.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/IR/Intrinsics.h"
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#include "llvm/IR/IntrinsicsSPIRV.h"
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#include "llvm/Transforms/Utils/Cloning.h"
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#include "llvm/Transforms/Utils/LowerMemIntrinsics.h"
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using namespace llvm;
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namespace llvm {
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void initializeSPIRVLegalizeAddrspaceCastPass(PassRegistry &);
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}
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class SPIRVLegalizeAddrspaceCast : public FunctionPass {
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public:
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SPIRVLegalizeAddrspaceCast(SPIRVTargetMachine *TM)
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: FunctionPass(ID), TM(TM) {
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initializeSPIRVLegalizeAddrspaceCastPass(*PassRegistry::getPassRegistry());
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};
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void gatherAddrspaceCast(Function &F) {
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WorkList.clear();
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std::vector<User *> ToVisit;
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for (auto &BB : F)
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for (auto &I : BB)
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ToVisit.push_back(&I);
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std::unordered_set<User *> Visited;
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while (ToVisit.size() > 0) {
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User *I = ToVisit.back();
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ToVisit.pop_back();
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if (Visited.count(I) != 0)
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continue;
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Visited.insert(I);
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if (AddrSpaceCastInst *AI = dyn_cast<AddrSpaceCastInst>(I))
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WorkList.insert(AI);
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else if (auto *AO = dyn_cast<AddrSpaceCastOperator>(I))
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WorkList.insert(AO);
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for (auto &O : I->operands())
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if (User *U = dyn_cast<User>(&O))
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ToVisit.push_back(U);
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}
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}
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void propagateAddrspace(User *U) {
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if (!U->getType()->isPointerTy())
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return;
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if (AddrSpaceCastOperator *AO = dyn_cast<AddrSpaceCastOperator>(U)) {
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for (auto &Use : AO->uses())
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WorkList.insert(Use.getUser());
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AO->mutateType(AO->getPointerOperand()->getType());
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AO->replaceAllUsesWith(AO->getPointerOperand());
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DeadUsers.insert(AO);
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return;
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}
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if (AddrSpaceCastInst *AC = dyn_cast<AddrSpaceCastInst>(U)) {
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for (auto &Use : AC->uses())
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WorkList.insert(Use.getUser());
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AC->mutateType(AC->getPointerOperand()->getType());
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AC->replaceAllUsesWith(AC->getPointerOperand());
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return;
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}
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PointerType *NewType = nullptr;
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for (Use &U : U->operands()) {
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PointerType *PT = dyn_cast<PointerType>(U.get()->getType());
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if (!PT)
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continue;
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if (NewType == nullptr)
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NewType = PT;
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else {
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// We could imagine a function calls taking 2 pointers to distinct
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// address spaces which returns a pointer. But we want to run this
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// pass after inlining, so we'll assume this doesn't happen.
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assert(NewType->getAddressSpace() == PT->getAddressSpace());
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}
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}
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assert(NewType != nullptr);
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U->mutateType(NewType);
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}
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virtual bool runOnFunction(Function &F) override {
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const SPIRVSubtarget &ST = TM->getSubtarget<SPIRVSubtarget>(F);
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GR = ST.getSPIRVGlobalRegistry();
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DeadUsers.clear();
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gatherAddrspaceCast(F);
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while (WorkList.size() > 0) {
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User *U = *WorkList.begin();
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WorkList.erase(U);
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propagateAddrspace(U);
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}
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for (User *U : DeadUsers) {
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if (Instruction *I = dyn_cast<Instruction>(U))
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I->eraseFromParent();
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}
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return DeadUsers.size() != 0;
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}
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private:
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SPIRVTargetMachine *TM = nullptr;
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SPIRVGlobalRegistry *GR = nullptr;
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std::unordered_set<User *> WorkList;
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std::unordered_set<User *> DeadUsers;
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public:
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static char ID;
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};
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char SPIRVLegalizeAddrspaceCast::ID = 0;
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INITIALIZE_PASS(SPIRVLegalizeAddrspaceCast, "spirv-legalize-addrspacecast",
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"SPIRV legalize addrspacecast", false, false)
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FunctionPass *
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llvm::createSPIRVLegalizeAddrspaceCastPass(SPIRVTargetMachine *TM) {
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return new SPIRVLegalizeAddrspaceCast(TM);
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}

‎llvm/lib/Target/SPIRV/SPIRVTargetMachine.cpp

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@@ -190,6 +190,8 @@ void SPIRVPassConfig::addIRPasses() {
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TargetPassConfig::addIRPasses();
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if (TM.getSubtargetImpl()->isVulkanEnv()) {
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addPass(createSPIRVLegalizeAddrspaceCastPass(&getTM<SPIRVTargetMachine>()));
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// 1. Simplify loop for subsequent transformations. After this steps, loops
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// have the following properties:
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// - loops have a single entry edge (pre-header to loop header).

‎llvm/test/CodeGen/SPIRV/pointers/resource-addrspacecast-2.ll

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; RUN: llc -verify-machineinstrs -O3 -mtriple=spirv-unknown-vulkan1.3-compute %s -o - | FileCheck %s --match-full-lines
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; RUN: %if spirv-tools %{ llc -O3 -mtriple=spirv-unknown-vulkan1.3-compute %s -o - -filetype=obj | spirv-val %}
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; FIXME(134119): enable-this once Offset decoration are added.
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; XFAIL: spirv-tools
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%S2 = type { { [10 x { i32, i32 } ] }, i32 }
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; CHECK-DAG: %[[#uint:]] = OpTypeInt 32 0
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; CHECK-DAG: %[[#uint_0:]] = OpConstant %[[#uint]] 0
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; CHECK-DAG: %[[#uint_1:]] = OpConstant %[[#uint]] 1
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; CHECK-DAG: %[[#uint_3:]] = OpConstant %[[#uint]] 3
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; CHECK-DAG: %[[#uint_10:]] = OpConstant %[[#uint]] 10
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; CHECK-DAG: %[[#uint_11:]] = OpConstant %[[#uint]] 11
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; CHECK-DAG: %[[#ptr_StorageBuffer_uint:]] = OpTypePointer StorageBuffer %[[#uint]]
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; CHECK-DAG: %[[#t_s2_s_a_s:]] = OpTypeStruct %[[#uint]] %[[#uint]]
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; CHECK-DAG: %[[#t_s2_s_a:]] = OpTypeArray %[[#t_s2_s_a_s]] %[[#uint_10]]
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; CHECK-DAG: %[[#t_s2_s:]] = OpTypeStruct %[[#t_s2_s_a]]
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; CHECK-DAG: %[[#t_s2:]] = OpTypeStruct %[[#t_s2_s]] %[[#uint]]
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; CHECK-DAG: %[[#ptr_StorageBuffer_struct:]] = OpTypePointer StorageBuffer %[[#t_s2]]
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; CHECK-DAG: %[[#rarr:]] = OpTypeRuntimeArray %[[#t_s2]]
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; CHECK-DAG: %[[#rarr_struct:]] = OpTypeStruct %[[#rarr]]
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; CHECK-DAG: %[[#spirv_VulkanBuffer:]] = OpTypePointer StorageBuffer %[[#rarr_struct]]
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declare target("spirv.VulkanBuffer", [0 x %S2], 12, 1) @llvm.spv.resource.handlefrombinding.tspirv.VulkanBuffer_a0s_Ss_12_1t(i32, i32, i32, i32, i1)
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define void @main() "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" {
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entry:
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%handle = tail call target("spirv.VulkanBuffer", [0 x %S2], 12, 1) @llvm.spv.resource.handlefrombinding.tspirv.VulkanBuffer_a0s_Ss_12_1t(i32 0, i32 0, i32 1, i32 0, i1 false)
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; CHECK: %[[#resource:]] = OpVariable %[[#spirv_VulkanBuffer]] StorageBuffer
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%ptr = tail call noundef align 4 dereferenceable(4) ptr addrspace(11) @llvm.spv.resource.getpointer.p11.tspirv.VulkanBuffer_a0s_Ss_12_1t(target("spirv.VulkanBuffer", [0 x %S2], 12, 1) %handle, i32 0)
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; CHECK: %[[#a:]] = OpCopyObject %[[#spirv_VulkanBuffer]] %[[#resource]]
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; CHECK: %[[#b:]] = OpAccessChain %[[#ptr_StorageBuffer_struct]] %[[#a:]] %[[#uint_0]] %[[#uint_0]]
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%casted = addrspacecast ptr addrspace(11) %ptr to ptr
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; CHECK: %[[#ptr2:]] = OpInBoundsAccessChain %[[#ptr_StorageBuffer_uint]] %[[#b:]] %[[#uint_0]] %[[#uint_0]] %[[#uint_3]] %[[#uint_1]]
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%ptr2 = getelementptr inbounds %S2, ptr %casted, i64 0, i32 0, i32 0, i32 3, i32 1
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; CHECK: OpStore %[[#ptr2]] %[[#uint_10]] Aligned 4
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store i32 10, ptr %ptr2, align 4
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; Another store, but this time using LLVM's ability to load the first element
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; without an explicit GEP. The backend has to determine the ptr type and
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; generate the appropriate access chain.
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; CHECK: %[[#ptr3:]] = OpInBoundsAccessChain %[[#ptr_StorageBuffer_uint]] %[[#b:]] %[[#uint_0]] %[[#uint_0]] %[[#uint_0]] %[[#uint_0]]
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; CHECK: OpStore %[[#ptr3]] %[[#uint_11]] Aligned 4
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store i32 11, ptr %casted, align 4
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ret void
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}
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declare ptr addrspace(11) @llvm.spv.resource.getpointer.p11.tspirv.VulkanBuffer_a0s_S2s_12_1t(target("spirv.VulkanBuffer", [0 x %S2], 12, 1), i32)

‎llvm/test/CodeGen/SPIRV/pointers/resource-addrspacecast.ll

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; RUN: llc -verify-machineinstrs -O3 -mtriple=spirv-unknown-vulkan1.3-compute %s -o - | FileCheck %s
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; RUN: %if spirv-tools %{ llc -O3 -mtriple=spirv-unknown-vulkan1.3-compute %s -o - -filetype=obj | spirv-val %}
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; FIXME(134119): enable-this once Offset decoration are added.
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; XFAIL: spirv-tools
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%struct.S = type { i32 }
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; CHECK-DAG: %[[#uint:]] = OpTypeInt 32 0
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; CHECK-DAG: %[[#uint_0:]] = OpConstant %[[#uint]] 0
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; CHECK-DAG: %[[#uint_10:]] = OpConstant %[[#uint]] 10
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; CHECK-DAG: %[[#ptr_StorageBuffer_uint:]] = OpTypePointer StorageBuffer %[[#uint]]
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; CHECK-DAG: %[[#struct:]] = OpTypeStruct %[[#uint]]
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; CHECK-DAG: %[[#ptr_StorageBuffer_struct:]] = OpTypePointer StorageBuffer %[[#struct]]
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; CHECK-DAG: %[[#rarr:]] = OpTypeRuntimeArray %[[#struct]]
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; CHECK-DAG: %[[#rarr_struct:]] = OpTypeStruct %[[#rarr]]
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; CHECK-DAG: %[[#spirv_VulkanBuffer:]] = OpTypePointer StorageBuffer %[[#rarr_struct]]
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declare target("spirv.VulkanBuffer", [0 x %struct.S], 12, 1) @llvm.spv.resource.handlefrombinding.tspirv.VulkanBuffer_a0s_struct.Ss_12_1t(i32, i32, i32, i32, i1)
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define void @main() "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" {
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entry:
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%handle = tail call target("spirv.VulkanBuffer", [0 x %struct.S], 12, 1) @llvm.spv.resource.handlefrombinding.tspirv.VulkanBuffer_a0s_struct.Ss_12_1t(i32 0, i32 0, i32 1, i32 0, i1 false)
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; CHECK: %[[#resource:]] = OpVariable %[[#spirv_VulkanBuffer]] StorageBuffer
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%ptr = tail call noundef align 4 dereferenceable(4) ptr addrspace(11) @llvm.spv.resource.getpointer.p11.tspirv.VulkanBuffer_a0s_struct.Ss_12_1t(target("spirv.VulkanBuffer", [0 x %struct.S], 12, 1) %handle, i32 0)
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; CHECK: %[[#a:]] = OpCopyObject %[[#spirv_VulkanBuffer]] %[[#resource]]
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; CHECK: %[[#b:]] = OpAccessChain %[[#ptr_StorageBuffer_struct]] %[[#a:]] %[[#uint_0]] %[[#uint_0]]
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; CHECK: %[[#c:]] = OpInBoundsAccessChain %[[#ptr_StorageBuffer_uint]] %[[#b:]] %[[#uint_0]]
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%casted = addrspacecast ptr addrspace(11) %ptr to ptr
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; CHECK: OpStore %[[#c]] %[[#uint_10]] Aligned 4
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store i32 10, ptr %casted, align 4
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ret void
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}
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declare ptr addrspace(11) @llvm.spv.resource.getpointer.p11.tspirv.VulkanBuffer_a0s_struct.Ss_12_1t(target("spirv.VulkanBuffer", [0 x %struct.S], 12, 1), i32)

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