1 //===-- BPFTargetMachine.cpp - Define TargetMachine for BPF ---------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Implements the info about BPF target spec.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "BPFTargetMachine.h"
15 #include "BPF.h"
16 #include "MCTargetDesc/BPFMCAsmInfo.h"
17 #include "llvm/CodeGen/Passes.h"
18 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
19 #include "llvm/CodeGen/TargetPassConfig.h"
20 #include "llvm/IR/LegacyPassManager.h"
21 #include "llvm/Support/FormattedStream.h"
22 #include "llvm/Support/TargetRegistry.h"
23 #include "llvm/Target/TargetOptions.h"
24 using namespace llvm;
25
26 static cl::
27 opt<bool> DisableMIPeephole("disable-bpf-peephole", cl::Hidden,
28 cl::desc("Disable machine peepholes for BPF"));
29
LLVMInitializeBPFTarget()30 extern "C" void LLVMInitializeBPFTarget() {
31 // Register the target.
32 RegisterTargetMachine<BPFTargetMachine> X(getTheBPFleTarget());
33 RegisterTargetMachine<BPFTargetMachine> Y(getTheBPFbeTarget());
34 RegisterTargetMachine<BPFTargetMachine> Z(getTheBPFTarget());
35
36 PassRegistry &PR = *PassRegistry::getPassRegistry();
37 initializeBPFMIPeepholePass(PR);
38 }
39
40 // DataLayout: little or big endian
computeDataLayout(const Triple & TT)41 static std::string computeDataLayout(const Triple &TT) {
42 if (TT.getArch() == Triple::bpfeb)
43 return "E-m:e-p:64:64-i64:64-n32:64-S128";
44 else
45 return "e-m:e-p:64:64-i64:64-n32:64-S128";
46 }
47
getEffectiveRelocModel(Optional<Reloc::Model> RM)48 static Reloc::Model getEffectiveRelocModel(Optional<Reloc::Model> RM) {
49 if (!RM.hasValue())
50 return Reloc::PIC_;
51 return *RM;
52 }
53
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)54 BPFTargetMachine::BPFTargetMachine(const Target &T, const Triple &TT,
55 StringRef CPU, StringRef FS,
56 const TargetOptions &Options,
57 Optional<Reloc::Model> RM,
58 Optional<CodeModel::Model> CM,
59 CodeGenOpt::Level OL, bool JIT)
60 : LLVMTargetMachine(T, computeDataLayout(TT), TT, CPU, FS, Options,
61 getEffectiveRelocModel(RM),
62 getEffectiveCodeModel(CM, CodeModel::Small), OL),
63 TLOF(make_unique<TargetLoweringObjectFileELF>()),
64 Subtarget(TT, CPU, FS, *this) {
65 initAsmInfo();
66
67 BPFMCAsmInfo *MAI =
68 static_cast<BPFMCAsmInfo *>(const_cast<MCAsmInfo *>(AsmInfo.get()));
69 MAI->setDwarfUsesRelocationsAcrossSections(!Subtarget.getUseDwarfRIS());
70 }
71 namespace {
72 // BPF Code Generator Pass Configuration Options.
73 class BPFPassConfig : public TargetPassConfig {
74 public:
BPFPassConfig(BPFTargetMachine & TM,PassManagerBase & PM)75 BPFPassConfig(BPFTargetMachine &TM, PassManagerBase &PM)
76 : TargetPassConfig(TM, PM) {}
77
getBPFTargetMachine() const78 BPFTargetMachine &getBPFTargetMachine() const {
79 return getTM<BPFTargetMachine>();
80 }
81
82 bool addInstSelector() override;
83 void addMachineSSAOptimization() override;
84 void addPreEmitPass() override;
85 };
86 }
87
createPassConfig(PassManagerBase & PM)88 TargetPassConfig *BPFTargetMachine::createPassConfig(PassManagerBase &PM) {
89 return new BPFPassConfig(*this, PM);
90 }
91
92 // Install an instruction selector pass using
93 // the ISelDag to gen BPF code.
addInstSelector()94 bool BPFPassConfig::addInstSelector() {
95 addPass(createBPFISelDag(getBPFTargetMachine()));
96
97 return false;
98 }
99
addMachineSSAOptimization()100 void BPFPassConfig::addMachineSSAOptimization() {
101 // The default implementation must be called first as we want eBPF
102 // Peephole ran at last.
103 TargetPassConfig::addMachineSSAOptimization();
104
105 const BPFSubtarget *Subtarget = getBPFTargetMachine().getSubtargetImpl();
106 if (Subtarget->getHasAlu32() && !DisableMIPeephole)
107 addPass(createBPFMIPeepholePass());
108 }
109
addPreEmitPass()110 void BPFPassConfig::addPreEmitPass() {
111 const BPFSubtarget *Subtarget = getBPFTargetMachine().getSubtargetImpl();
112
113 addPass(createBPFMIPreEmitCheckingPass());
114 if (getOptLevel() != CodeGenOpt::None)
115 if (Subtarget->getHasAlu32() && !DisableMIPeephole)
116 addPass(createBPFMIPreEmitPeepholePass());
117 }
118