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1bc276c3c4
JMP32 instructions has been added to eBPF ISA. They are 32-bit variants of existing BPF conditional jump instructions, but the comparison happens on low 32-bit sub-register only, therefore some unnecessary extensions could be saved. JMP32 instructions will only be available for -mcpu=v3. Host probe hook has been updated accordingly. JMP32 instructions will only be enabled in code-gen when -mattr=+alu32 enabled, meaning compiling the program using sub-register mode. For JMP32 encoding, it is a new instruction class, and is using the reserved eBPF class number 0x6. This patch has been tested by compiling and running kernel bpf selftests with JMP32 enabled. Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Jiong Wang <jiong.wang@netronome.com> llvm-svn: 353384
64 lines
1.8 KiB
C++
64 lines
1.8 KiB
C++
//===-- BPFSubtarget.cpp - BPF Subtarget Information ----------------------===//
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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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//
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// This file implements the BPF specific subclass of TargetSubtargetInfo.
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//
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//===----------------------------------------------------------------------===//
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#include "BPFSubtarget.h"
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#include "BPF.h"
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#include "llvm/Support/Host.h"
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#include "llvm/Support/TargetRegistry.h"
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using namespace llvm;
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#define DEBUG_TYPE "bpf-subtarget"
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#define GET_SUBTARGETINFO_TARGET_DESC
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#define GET_SUBTARGETINFO_CTOR
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#include "BPFGenSubtargetInfo.inc"
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void BPFSubtarget::anchor() {}
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BPFSubtarget &BPFSubtarget::initializeSubtargetDependencies(StringRef CPU,
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StringRef FS) {
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initializeEnvironment();
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initSubtargetFeatures(CPU, FS);
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ParseSubtargetFeatures(CPU, FS);
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return *this;
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}
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void BPFSubtarget::initializeEnvironment() {
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HasJmpExt = false;
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HasJmp32 = false;
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HasAlu32 = false;
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UseDwarfRIS = false;
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}
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void BPFSubtarget::initSubtargetFeatures(StringRef CPU, StringRef FS) {
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if (CPU == "probe")
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CPU = sys::detail::getHostCPUNameForBPF();
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if (CPU == "generic" || CPU == "v1")
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return;
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if (CPU == "v2") {
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HasJmpExt = true;
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return;
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}
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if (CPU == "v3") {
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HasJmpExt = true;
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HasJmp32 = true;
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return;
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}
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}
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BPFSubtarget::BPFSubtarget(const Triple &TT, const std::string &CPU,
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const std::string &FS, const TargetMachine &TM)
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: BPFGenSubtargetInfo(TT, CPU, FS), InstrInfo(),
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FrameLowering(initializeSubtargetDependencies(CPU, FS)),
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TLInfo(TM, *this) {}
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