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llvm-mirror/lib/Target/BPF/BPFSubtarget.cpp
Yonghong Song d771b3fb3e [BPF] turn on -mattr=+alu32 for cpu version v3 and later
-mattr=+alu32 has shown good performance vs. without this attribute.
Based on discussion at
  https://lore.kernel.org/bpf/1ec37838-966f-ec0b-5223-ca9b6eb0860d@fb.com/T/#t
cpu version v3 should support -mattr=+alu32.
This patch enabled alu32 if cpu version is v3, either specified by user
or probed by the llvm.

Differential Revision: https://reviews.llvm.org/D69957
2019-11-07 22:08:46 -08:00

65 lines
1.8 KiB
C++

//===-- BPFSubtarget.cpp - BPF Subtarget Information ----------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements the BPF specific subclass of TargetSubtargetInfo.
//
//===----------------------------------------------------------------------===//
#include "BPFSubtarget.h"
#include "BPF.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/TargetRegistry.h"
using namespace llvm;
#define DEBUG_TYPE "bpf-subtarget"
#define GET_SUBTARGETINFO_TARGET_DESC
#define GET_SUBTARGETINFO_CTOR
#include "BPFGenSubtargetInfo.inc"
void BPFSubtarget::anchor() {}
BPFSubtarget &BPFSubtarget::initializeSubtargetDependencies(StringRef CPU,
StringRef FS) {
initializeEnvironment();
initSubtargetFeatures(CPU, FS);
ParseSubtargetFeatures(CPU, FS);
return *this;
}
void BPFSubtarget::initializeEnvironment() {
HasJmpExt = false;
HasJmp32 = false;
HasAlu32 = false;
UseDwarfRIS = false;
}
void BPFSubtarget::initSubtargetFeatures(StringRef CPU, StringRef FS) {
if (CPU == "probe")
CPU = sys::detail::getHostCPUNameForBPF();
if (CPU == "generic" || CPU == "v1")
return;
if (CPU == "v2") {
HasJmpExt = true;
return;
}
if (CPU == "v3") {
HasJmpExt = true;
HasJmp32 = true;
HasAlu32 = true;
return;
}
}
BPFSubtarget::BPFSubtarget(const Triple &TT, const std::string &CPU,
const std::string &FS, const TargetMachine &TM)
: BPFGenSubtargetInfo(TT, CPU, FS), InstrInfo(),
FrameLowering(initializeSubtargetDependencies(CPU, FS)),
TLInfo(TM, *this) {}