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//===- SPIRVTargetMachine.cpp - Define TargetMachine for SPIR-V -*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Implements the info about SPIR-V target spec.
//
//===----------------------------------------------------------------------===//
#include "SPIRVTargetMachine.h"
#include "SPIRV.h"
#include "SPIRVCallLowering.h"
#include "SPIRVGlobalRegistry.h"
#include "SPIRVLegalizerInfo.h"
#include "SPIRVTargetObjectFile.h"
#include "SPIRVTargetTransformInfo.h"
#include "TargetInfo/SPIRVTargetInfo.h"
#include "llvm/CodeGen/GlobalISel/IRTranslator.h"
#include "llvm/CodeGen/GlobalISel/InstructionSelect.h"
#include "llvm/CodeGen/GlobalISel/Legalizer.h"
#include "llvm/CodeGen/GlobalISel/RegBankSelect.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/InitializePasses.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Pass.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Transforms/Utils.h"
#include <optional>
using namespace llvm;
extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeSPIRVTarget() {
// Register the target.
RegisterTargetMachine<SPIRVTargetMachine> X(getTheSPIRV32Target());
RegisterTargetMachine<SPIRVTargetMachine> Y(getTheSPIRV64Target());
RegisterTargetMachine<SPIRVTargetMachine> Z(getTheSPIRVLogicalTarget());
PassRegistry &PR = *PassRegistry::getPassRegistry();
initializeGlobalISel(PR);
initializeSPIRVModuleAnalysisPass(PR);
initializeSPIRVConvergenceRegionAnalysisWrapperPassPass(PR);
}
static std::string computeDataLayout(const Triple &TT) {
const auto Arch = TT.getArch();
// TODO: this probably needs to be revisited:
// Logical SPIR-V has no pointer size, so any fixed pointer size would be
// wrong. The choice to default to 32 or 64 is just motivated by another
// memory model used for graphics: PhysicalStorageBuffer64. But it shouldn't
// mean anything.
if (Arch == Triple::spirv32)
return "e-p:32:32-i64:64-v16:16-v24:32-v32:32-v48:64-"
"v96:128-v192:256-v256:256-v512:512-v1024:1024";
return "e-i64:64-v16:16-v24:32-v32:32-v48:64-"
"v96:128-v192:256-v256:256-v512:512-v1024:1024";
}
static Reloc::Model getEffectiveRelocModel(std::optional<Reloc::Model> RM) {
if (!RM)
return Reloc::PIC_;
return *RM;
}
// Pin SPIRVTargetObjectFile's vtables to this file.
SPIRVTargetObjectFile::~SPIRVTargetObjectFile() {}
SPIRVTargetMachine::SPIRVTargetMachine(const Target &T, const Triple &TT,
StringRef CPU, StringRef FS,
const TargetOptions &Options,
std::optional<Reloc::Model> RM,
std::optional<CodeModel::Model> CM,
CodeGenOptLevel OL, bool JIT)
: LLVMTargetMachine(T, computeDataLayout(TT), TT, CPU, FS, Options,
getEffectiveRelocModel(RM),
getEffectiveCodeModel(CM, CodeModel::Small), OL),
TLOF(std::make_unique<SPIRVTargetObjectFile>()),
Subtarget(TT, CPU.str(), FS.str(), *this) {
initAsmInfo();
setGlobalISel(true);
setFastISel(false);
setO0WantsFastISel(false);
setRequiresStructuredCFG(false);
}
namespace {
// SPIR-V Code Generator Pass Configuration Options.
class SPIRVPassConfig : public TargetPassConfig {
public:
SPIRVPassConfig(SPIRVTargetMachine &TM, PassManagerBase &PM)
: TargetPassConfig(TM, PM), TM(TM) {}
SPIRVTargetMachine &getSPIRVTargetMachine() const {
return getTM<SPIRVTargetMachine>();
}
void addIRPasses() override;
void addISelPrepare() override;
bool addIRTranslator() override;
void addPreLegalizeMachineIR() override;
bool addLegalizeMachineIR() override;
bool addRegBankSelect() override;
bool addGlobalInstructionSelect() override;
FunctionPass *createTargetRegisterAllocator(bool) override;
void addFastRegAlloc() override {}
void addOptimizedRegAlloc() override {}
void addPostRegAlloc() override;
private:
const SPIRVTargetMachine &TM;
};
} // namespace
// We do not use physical registers, and maintain virtual registers throughout
// the entire pipeline, so return nullptr to disable register allocation.
FunctionPass *SPIRVPassConfig::createTargetRegisterAllocator(bool) {
return nullptr;
}
// Disable passes that break from assuming no virtual registers exist.
void SPIRVPassConfig::addPostRegAlloc() {
// Do not work with vregs instead of physical regs.
disablePass(&MachineCopyPropagationID);
disablePass(&PostRAMachineSinkingID);
disablePass(&PostRASchedulerID);
disablePass(&FuncletLayoutID);
disablePass(&StackMapLivenessID);
disablePass(&PatchableFunctionID);
disablePass(&ShrinkWrapID);
disablePass(&LiveDebugValuesID);
disablePass(&MachineLateInstrsCleanupID);
// Do not work with OpPhi.
disablePass(&BranchFolderPassID);
disablePass(&MachineBlockPlacementID);
TargetPassConfig::addPostRegAlloc();
}
TargetTransformInfo
SPIRVTargetMachine::getTargetTransformInfo(const Function &F) const {
return TargetTransformInfo(SPIRVTTIImpl(this, F));
}
TargetPassConfig *SPIRVTargetMachine::createPassConfig(PassManagerBase &PM) {
return new SPIRVPassConfig(*this, PM);
}
void SPIRVPassConfig::addIRPasses() {
if (TM.getSubtargetImpl()->isVulkanEnv()) {
// Once legalized, we need to structurize the CFG to follow the spec.
// This is done through the following 8 steps.
// TODO(#75801): add the remaining steps.
// 1. Simplify loop for subsequent transformations. After this steps, loops
// have the following properties:
// - loops have a single entry edge (pre-header to loop header).
// - all loop exits are dominated by the loop pre-header.
// - loops have a single back-edge.
addPass(createLoopSimplifyPass());
}
TargetPassConfig::addIRPasses();
addPass(createSPIRVRegularizerPass());
addPass(createSPIRVPrepareFunctionsPass(TM));
addPass(createSPIRVStripConvergenceIntrinsicsPass());
}
void SPIRVPassConfig::addISelPrepare() {
addPass(createSPIRVEmitIntrinsicsPass(&getTM<SPIRVTargetMachine>()));
TargetPassConfig::addISelPrepare();
}
bool SPIRVPassConfig::addIRTranslator() {
addPass(new IRTranslator(getOptLevel()));
return false;
}
void SPIRVPassConfig::addPreLegalizeMachineIR() {
addPass(createSPIRVPreLegalizerPass());
}
// Use the default legalizer.
bool SPIRVPassConfig::addLegalizeMachineIR() {
addPass(new Legalizer());
addPass(createSPIRVPostLegalizerPass());
return false;
}
// Do not add the RegBankSelect pass, as we only ever need virtual registers.
bool SPIRVPassConfig::addRegBankSelect() {
disablePass(&RegBankSelect::ID);
return false;
}
namespace {
// A custom subclass of InstructionSelect, which is mostly the same except from
// not requiring RegBankSelect to occur previously.
class SPIRVInstructionSelect : public InstructionSelect {
// We don't use register banks, so unset the requirement for them
MachineFunctionProperties getRequiredProperties() const override {
return InstructionSelect::getRequiredProperties().reset(
MachineFunctionProperties::Property::RegBankSelected);
}
};
} // namespace
// Add the custom SPIRVInstructionSelect from above.
bool SPIRVPassConfig::addGlobalInstructionSelect() {
addPass(new SPIRVInstructionSelect());
return false;
}
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