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//===-- BPFTargetMachine.cpp - Define TargetMachine for BPF ---------------===//
//
// 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 BPF target spec.
//
//===----------------------------------------------------------------------===//
#include "BPFTargetMachine.h"
#include "BPF.h"
#include "MCTargetDesc/BPFMCAsmInfo.h"
#include "TargetInfo/BPFTargetInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Target/TargetOptions.h"
using namespace llvm;
static cl::
opt<bool> DisableMIPeephole("disable-bpf-peephole", cl::Hidden,
cl::desc("Disable machine peepholes for BPF"));
extern "C" void LLVMInitializeBPFTarget() {
// Register the target.
RegisterTargetMachine<BPFTargetMachine> X(getTheBPFleTarget());
RegisterTargetMachine<BPFTargetMachine> Y(getTheBPFbeTarget());
RegisterTargetMachine<BPFTargetMachine> Z(getTheBPFTarget());
PassRegistry &PR = *PassRegistry::getPassRegistry();
initializeBPFAbstractMemberAccessPass(PR);
initializeBPFMIPeepholePass(PR);
initializeBPFMIPeepholeTruncElimPass(PR);
}
// DataLayout: little or big endian
static std::string computeDataLayout(const Triple &TT) {
if (TT.getArch() == Triple::bpfeb)
return "E-m:e-p:64:64-i64:64-n32:64-S128";
else
return "e-m:e-p:64:64-i64:64-n32:64-S128";
}
static Reloc::Model getEffectiveRelocModel(Optional<Reloc::Model> RM) {
if (!RM.hasValue())
return Reloc::PIC_;
return *RM;
}
BPFTargetMachine::BPFTargetMachine(const Target &T, const Triple &TT,
StringRef CPU, StringRef FS,
const TargetOptions &Options,
Optional<Reloc::Model> RM,
Optional<CodeModel::Model> CM,
CodeGenOpt::Level OL, bool JIT)
: LLVMTargetMachine(T, computeDataLayout(TT), TT, CPU, FS, Options,
getEffectiveRelocModel(RM),
getEffectiveCodeModel(CM, CodeModel::Small), OL),
TLOF(std::make_unique<TargetLoweringObjectFileELF>()),
Subtarget(TT, CPU, FS, *this) {
initAsmInfo();
BPFMCAsmInfo *MAI =
static_cast<BPFMCAsmInfo *>(const_cast<MCAsmInfo *>(AsmInfo.get()));
MAI->setDwarfUsesRelocationsAcrossSections(!Subtarget.getUseDwarfRIS());
}
namespace {
// BPF Code Generator Pass Configuration Options.
class BPFPassConfig : public TargetPassConfig {
public:
BPFPassConfig(BPFTargetMachine &TM, PassManagerBase &PM)
: TargetPassConfig(TM, PM) {}
BPFTargetMachine &getBPFTargetMachine() const {
return getTM<BPFTargetMachine>();
}
void addIRPasses() override;
bool addInstSelector() override;
void addMachineSSAOptimization() override;
void addPreEmitPass() override;
};
}
TargetPassConfig *BPFTargetMachine::createPassConfig(PassManagerBase &PM) {
return new BPFPassConfig(*this, PM);
}
void BPFPassConfig::addIRPasses() {
addPass(createBPFAbstractMemberAccess(&getBPFTargetMachine()));
TargetPassConfig::addIRPasses();
}
// Install an instruction selector pass using
// the ISelDag to gen BPF code.
bool BPFPassConfig::addInstSelector() {
addPass(createBPFISelDag(getBPFTargetMachine()));
return false;
}
void BPFPassConfig::addMachineSSAOptimization() {
addPass(createBPFMISimplifyPatchablePass());
// The default implementation must be called first as we want eBPF
// Peephole ran at last.
TargetPassConfig::addMachineSSAOptimization();
const BPFSubtarget *Subtarget = getBPFTargetMachine().getSubtargetImpl();
if (!DisableMIPeephole) {
if (Subtarget->getHasAlu32())
addPass(createBPFMIPeepholePass());
addPass(createBPFMIPeepholeTruncElimPass());
}
}
void BPFPassConfig::addPreEmitPass() {
addPass(createBPFMIPreEmitCheckingPass());
if (getOptLevel() != CodeGenOpt::None)
if (!DisableMIPeephole)
addPass(createBPFMIPreEmitPeepholePass());
}
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