1 //===-- BPFTargetMachine.cpp - Define TargetMachine for BPF ---------------===//
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
7 //===----------------------------------------------------------------------===//
9 // Implements the info about BPF target spec.
11 //===----------------------------------------------------------------------===//
13 #include "BPFTargetMachine.h"
15 #include "BPFTargetTransformInfo.h"
16 #include "MCTargetDesc/BPFMCAsmInfo.h"
17 #include "TargetInfo/BPFTargetInfo.h"
18 #include "llvm/CodeGen/Passes.h"
19 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
20 #include "llvm/CodeGen/TargetPassConfig.h"
21 #include "llvm/IR/LegacyPassManager.h"
22 #include "llvm/IR/PassManager.h"
23 #include "llvm/MC/TargetRegistry.h"
24 #include "llvm/Passes/PassBuilder.h"
25 #include "llvm/Support/FormattedStream.h"
26 #include "llvm/Target/TargetOptions.h"
27 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
28 #include "llvm/Transforms/Scalar.h"
29 #include "llvm/Transforms/Scalar/SimplifyCFG.h"
30 #include "llvm/Transforms/Utils/SimplifyCFGOptions.h"
34 opt<bool> DisableMIPeephole("disable-bpf-peephole", cl::Hidden,
35 cl::desc("Disable machine peepholes for BPF"));
37 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeBPFTarget() {
38 // Register the target.
39 RegisterTargetMachine<BPFTargetMachine> X(getTheBPFleTarget());
40 RegisterTargetMachine<BPFTargetMachine> Y(getTheBPFbeTarget());
41 RegisterTargetMachine<BPFTargetMachine> Z(getTheBPFTarget());
43 PassRegistry &PR = *PassRegistry::getPassRegistry();
44 initializeBPFAbstractMemberAccessLegacyPassPass(PR);
45 initializeBPFPreserveDITypePass(PR);
46 initializeBPFIRPeepholePass(PR);
47 initializeBPFAdjustOptPass(PR);
48 initializeBPFCheckAndAdjustIRPass(PR);
49 initializeBPFMIPeepholePass(PR);
50 initializeBPFMIPeepholeTruncElimPass(PR);
53 // DataLayout: little or big endian
54 static std::string computeDataLayout(const Triple &TT) {
55 if (TT.getArch() == Triple::bpfeb)
56 return "E-m:e-p:64:64-i64:64-i128:128-n32:64-S128";
58 return "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128";
61 static Reloc::Model getEffectiveRelocModel(Optional<Reloc::Model> RM) {
62 return RM.value_or(Reloc::PIC_);
65 BPFTargetMachine::BPFTargetMachine(const Target &T, const Triple &TT,
66 StringRef CPU, StringRef FS,
67 const TargetOptions &Options,
68 Optional<Reloc::Model> RM,
69 Optional<CodeModel::Model> CM,
70 CodeGenOpt::Level OL, bool JIT)
71 : LLVMTargetMachine(T, computeDataLayout(TT), TT, CPU, FS, Options,
72 getEffectiveRelocModel(RM),
73 getEffectiveCodeModel(CM, CodeModel::Small), OL),
74 TLOF(std::make_unique<TargetLoweringObjectFileELF>()),
75 Subtarget(TT, std::string(CPU), std::string(FS), *this) {
79 static_cast<BPFMCAsmInfo *>(const_cast<MCAsmInfo *>(AsmInfo.get()));
80 MAI->setDwarfUsesRelocationsAcrossSections(!Subtarget.getUseDwarfRIS());
84 // BPF Code Generator Pass Configuration Options.
85 class BPFPassConfig : public TargetPassConfig {
87 BPFPassConfig(BPFTargetMachine &TM, PassManagerBase &PM)
88 : TargetPassConfig(TM, PM) {}
90 BPFTargetMachine &getBPFTargetMachine() const {
91 return getTM<BPFTargetMachine>();
94 void addIRPasses() override;
95 bool addInstSelector() override;
96 void addMachineSSAOptimization() override;
97 void addPreEmitPass() override;
101 TargetPassConfig *BPFTargetMachine::createPassConfig(PassManagerBase &PM) {
102 return new BPFPassConfig(*this, PM);
105 void BPFTargetMachine::adjustPassManager(PassManagerBuilder &Builder) {
106 Builder.addExtension(
107 PassManagerBuilder::EP_EarlyAsPossible,
108 [&](const PassManagerBuilder &, legacy::PassManagerBase &PM) {
109 PM.add(createBPFAbstractMemberAccess(this));
110 PM.add(createBPFPreserveDIType());
111 PM.add(createBPFIRPeephole());
114 Builder.addExtension(
115 PassManagerBuilder::EP_Peephole,
116 [&](const PassManagerBuilder &, legacy::PassManagerBase &PM) {
117 PM.add(createCFGSimplificationPass(
118 SimplifyCFGOptions().hoistCommonInsts(true)));
120 Builder.addExtension(
121 PassManagerBuilder::EP_ModuleOptimizerEarly,
122 [&](const PassManagerBuilder &, legacy::PassManagerBase &PM) {
123 PM.add(createBPFAdjustOpt());
127 void BPFTargetMachine::registerPassBuilderCallbacks(PassBuilder &PB) {
128 PB.registerPipelineStartEPCallback(
129 [=](ModulePassManager &MPM, OptimizationLevel) {
130 FunctionPassManager FPM;
131 FPM.addPass(BPFAbstractMemberAccessPass(this));
132 FPM.addPass(BPFPreserveDITypePass());
133 FPM.addPass(BPFIRPeepholePass());
134 MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
136 PB.registerPeepholeEPCallback([=](FunctionPassManager &FPM,
137 OptimizationLevel Level) {
138 FPM.addPass(SimplifyCFGPass(SimplifyCFGOptions().hoistCommonInsts(true)));
140 PB.registerPipelineEarlySimplificationEPCallback(
141 [=](ModulePassManager &MPM, OptimizationLevel) {
142 MPM.addPass(BPFAdjustOptPass());
146 void BPFPassConfig::addIRPasses() {
147 addPass(createBPFCheckAndAdjustIR());
148 TargetPassConfig::addIRPasses();
152 BPFTargetMachine::getTargetTransformInfo(const Function &F) const {
153 return TargetTransformInfo(BPFTTIImpl(this, F));
156 // Install an instruction selector pass using
157 // the ISelDag to gen BPF code.
158 bool BPFPassConfig::addInstSelector() {
159 addPass(createBPFISelDag(getBPFTargetMachine()));
164 void BPFPassConfig::addMachineSSAOptimization() {
165 addPass(createBPFMISimplifyPatchablePass());
167 // The default implementation must be called first as we want eBPF
168 // Peephole ran at last.
169 TargetPassConfig::addMachineSSAOptimization();
171 const BPFSubtarget *Subtarget = getBPFTargetMachine().getSubtargetImpl();
172 if (!DisableMIPeephole) {
173 if (Subtarget->getHasAlu32())
174 addPass(createBPFMIPeepholePass());
175 addPass(createBPFMIPeepholeTruncElimPass());
179 void BPFPassConfig::addPreEmitPass() {
180 addPass(createBPFMIPreEmitCheckingPass());
181 if (getOptLevel() != CodeGenOpt::None)
182 if (!DisableMIPeephole)
183 addPass(createBPFMIPreEmitPeepholePass());