1//===-- BPFTargetMachine.cpp - Define TargetMachine for BPF ---------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Implements the info about BPF target spec.
10//
11//===----------------------------------------------------------------------===//
12
13#include "BPFTargetMachine.h"
14#include "BPF.h"
15#include "BPFTargetTransformInfo.h"
16#include "MCTargetDesc/BPFMCAsmInfo.h"
17#include "TargetInfo/BPFTargetInfo.h"
18#include "llvm/CodeGen/GlobalISel/IRTranslator.h"
19#include "llvm/CodeGen/GlobalISel/InstructionSelect.h"
20#include "llvm/CodeGen/GlobalISel/Legalizer.h"
21#include "llvm/CodeGen/GlobalISel/RegBankSelect.h"
22#include "llvm/CodeGen/Passes.h"
23#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
24#include "llvm/CodeGen/TargetPassConfig.h"
25#include "llvm/IR/PassManager.h"
26#include "llvm/InitializePasses.h"
27#include "llvm/MC/TargetRegistry.h"
28#include "llvm/Passes/PassBuilder.h"
29#include "llvm/Support/FormattedStream.h"
30#include "llvm/Target/TargetOptions.h"
31#include "llvm/Transforms/Scalar.h"
32#include "llvm/Transforms/Scalar/SimplifyCFG.h"
33#include "llvm/Transforms/Utils/SimplifyCFGOptions.h"
34#include <optional>
35using namespace llvm;
36
37static cl::
38opt<bool> DisableMIPeephole("disable-bpf-peephole", cl::Hidden,
39 cl::desc("Disable machine peepholes for BPF"));
40
41extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeBPFTarget() {
42 // Register the target.
43 RegisterTargetMachine<BPFTargetMachine> X(getTheBPFleTarget());
44 RegisterTargetMachine<BPFTargetMachine> Y(getTheBPFbeTarget());
45 RegisterTargetMachine<BPFTargetMachine> Z(getTheBPFTarget());
46
47 PassRegistry &PR = *PassRegistry::getPassRegistry();
48 initializeGlobalISel(PR);
49 initializeBPFCheckAndAdjustIRPass(PR);
50 initializeBPFMIPeepholePass(PR);
51 initializeBPFDAGToDAGISelPass(PR);
52}
53
54// DataLayout: little or big endian
55static std::string computeDataLayout(const Triple &TT) {
56 if (TT.getArch() == Triple::bpfeb)
57 return "E-m:e-p:64:64-i64:64-i128:128-n32:64-S128";
58 else
59 return "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128";
60}
61
62static Reloc::Model getEffectiveRelocModel(std::optional<Reloc::Model> RM) {
63 return RM.value_or(u: Reloc::PIC_);
64}
65
66BPFTargetMachine::BPFTargetMachine(const Target &T, const Triple &TT,
67 StringRef CPU, StringRef FS,
68 const TargetOptions &Options,
69 std::optional<Reloc::Model> RM,
70 std::optional<CodeModel::Model> CM,
71 CodeGenOptLevel OL, bool JIT)
72 : LLVMTargetMachine(T, computeDataLayout(TT), TT, CPU, FS, Options,
73 getEffectiveRelocModel(RM),
74 getEffectiveCodeModel(CM, Default: CodeModel::Small), OL),
75 TLOF(std::make_unique<TargetLoweringObjectFileELF>()),
76 Subtarget(TT, std::string(CPU), std::string(FS), *this) {
77 initAsmInfo();
78
79 BPFMCAsmInfo *MAI =
80 static_cast<BPFMCAsmInfo *>(const_cast<MCAsmInfo *>(AsmInfo.get()));
81 MAI->setDwarfUsesRelocationsAcrossSections(!Subtarget.getUseDwarfRIS());
82}
83
84namespace {
85// BPF Code Generator Pass Configuration Options.
86class BPFPassConfig : public TargetPassConfig {
87public:
88 BPFPassConfig(BPFTargetMachine &TM, PassManagerBase &PM)
89 : TargetPassConfig(TM, PM) {}
90
91 BPFTargetMachine &getBPFTargetMachine() const {
92 return getTM<BPFTargetMachine>();
93 }
94
95 void addIRPasses() override;
96 bool addInstSelector() override;
97 void addMachineSSAOptimization() override;
98 void addPreEmitPass() override;
99
100 bool addIRTranslator() override;
101 bool addLegalizeMachineIR() override;
102 bool addRegBankSelect() override;
103 bool addGlobalInstructionSelect() override;
104};
105}
106
107TargetPassConfig *BPFTargetMachine::createPassConfig(PassManagerBase &PM) {
108 return new BPFPassConfig(*this, PM);
109}
110
111static Expected<bool> parseBPFPreserveStaticOffsetOptions(StringRef Params) {
112 return PassBuilder::parseSinglePassOption(Params, OptionName: "allow-partial",
113 PassName: "BPFPreserveStaticOffsetPass");
114}
115
116void BPFTargetMachine::registerPassBuilderCallbacks(
117 PassBuilder &PB, bool PopulateClassToPassNames) {
118#define GET_PASS_REGISTRY "BPFPassRegistry.def"
119#include "llvm/Passes/TargetPassRegistry.inc"
120
121 PB.registerPipelineStartEPCallback(
122 C: [=](ModulePassManager &MPM, OptimizationLevel) {
123 FunctionPassManager FPM;
124 FPM.addPass(Pass: BPFPreserveStaticOffsetPass(true));
125 FPM.addPass(Pass: BPFAbstractMemberAccessPass(this));
126 FPM.addPass(Pass: BPFPreserveDITypePass());
127 FPM.addPass(Pass: BPFIRPeepholePass());
128 MPM.addPass(Pass: createModuleToFunctionPassAdaptor(Pass: std::move(FPM)));
129 });
130 PB.registerPeepholeEPCallback(C: [=](FunctionPassManager &FPM,
131 OptimizationLevel Level) {
132 FPM.addPass(Pass: SimplifyCFGPass(SimplifyCFGOptions().hoistCommonInsts(B: true)));
133 FPM.addPass(Pass: BPFASpaceCastSimplifyPass());
134 });
135 PB.registerScalarOptimizerLateEPCallback(
136 C: [=](FunctionPassManager &FPM, OptimizationLevel Level) {
137 // Run this after loop unrolling but before
138 // SimplifyCFGPass(... .sinkCommonInsts(true))
139 FPM.addPass(Pass: BPFPreserveStaticOffsetPass(false));
140 });
141 PB.registerPipelineEarlySimplificationEPCallback(
142 C: [=](ModulePassManager &MPM, OptimizationLevel) {
143 MPM.addPass(Pass: BPFAdjustOptPass());
144 });
145}
146
147void BPFPassConfig::addIRPasses() {
148 addPass(P: createAtomicExpandLegacyPass());
149 addPass(P: createBPFCheckAndAdjustIR());
150
151 TargetPassConfig::addIRPasses();
152}
153
154TargetTransformInfo
155BPFTargetMachine::getTargetTransformInfo(const Function &F) const {
156 return TargetTransformInfo(BPFTTIImpl(this, F));
157}
158
159// Install an instruction selector pass using
160// the ISelDag to gen BPF code.
161bool BPFPassConfig::addInstSelector() {
162 addPass(P: createBPFISelDag(TM&: getBPFTargetMachine()));
163
164 return false;
165}
166
167void BPFPassConfig::addMachineSSAOptimization() {
168 addPass(P: createBPFMISimplifyPatchablePass());
169
170 // The default implementation must be called first as we want eBPF
171 // Peephole ran at last.
172 TargetPassConfig::addMachineSSAOptimization();
173
174 const BPFSubtarget *Subtarget = getBPFTargetMachine().getSubtargetImpl();
175 if (!DisableMIPeephole) {
176 if (Subtarget->getHasAlu32())
177 addPass(P: createBPFMIPeepholePass());
178 }
179}
180
181void BPFPassConfig::addPreEmitPass() {
182 addPass(P: createBPFMIPreEmitCheckingPass());
183 if (getOptLevel() != CodeGenOptLevel::None)
184 if (!DisableMIPeephole)
185 addPass(P: createBPFMIPreEmitPeepholePass());
186}
187
188bool BPFPassConfig::addIRTranslator() {
189 addPass(P: new IRTranslator());
190 return false;
191}
192
193bool BPFPassConfig::addLegalizeMachineIR() {
194 addPass(P: new Legalizer());
195 return false;
196}
197
198bool BPFPassConfig::addRegBankSelect() {
199 addPass(P: new RegBankSelect());
200 return false;
201}
202
203bool BPFPassConfig::addGlobalInstructionSelect() {
204 addPass(P: new InstructionSelect(getOptLevel()));
205 return false;
206}
207

source code of llvm/lib/Target/BPF/BPFTargetMachine.cpp