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 "llvm/CodeGen/Passes.h"
17 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
18 #include "llvm/CodeGen/TargetPassConfig.h"
19 #include "llvm/IR/LegacyPassManager.h"
20 #include "llvm/Support/FormattedStream.h"
21 #include "llvm/Support/TargetRegistry.h"
22 #include "llvm/Target/TargetOptions.h"
23 using namespace llvm;
24 
25 extern "C" void LLVMInitializeBPFTarget() {
26   // Register the target.
27   RegisterTargetMachine<BPFTargetMachine> X(getTheBPFleTarget());
28   RegisterTargetMachine<BPFTargetMachine> Y(getTheBPFbeTarget());
29   RegisterTargetMachine<BPFTargetMachine> Z(getTheBPFTarget());
30 }
31 
32 // DataLayout: little or big endian
33 static std::string computeDataLayout(const Triple &TT) {
34   if (TT.getArch() == Triple::bpfeb)
35     return "E-m:e-p:64:64-i64:64-n32:64-S128";
36   else
37     return "e-m:e-p:64:64-i64:64-n32:64-S128";
38 }
39 
40 static Reloc::Model getEffectiveRelocModel(Optional<Reloc::Model> RM) {
41   if (!RM.hasValue())
42     return Reloc::PIC_;
43   return *RM;
44 }
45 
46 static CodeModel::Model getEffectiveCodeModel(Optional<CodeModel::Model> CM) {
47   if (CM)
48     return *CM;
49   return CodeModel::Small;
50 }
51 
52 BPFTargetMachine::BPFTargetMachine(const Target &T, const Triple &TT,
53                                    StringRef CPU, StringRef FS,
54                                    const TargetOptions &Options,
55                                    Optional<Reloc::Model> RM,
56                                    Optional<CodeModel::Model> CM,
57                                    CodeGenOpt::Level OL, bool JIT)
58     : LLVMTargetMachine(T, computeDataLayout(TT), TT, CPU, FS, Options,
59                         getEffectiveRelocModel(RM), getEffectiveCodeModel(CM),
60                         OL),
61       TLOF(make_unique<TargetLoweringObjectFileELF>()),
62       Subtarget(TT, CPU, FS, *this) {
63   initAsmInfo();
64 }
65 namespace {
66 // BPF Code Generator Pass Configuration Options.
67 class BPFPassConfig : public TargetPassConfig {
68 public:
69   BPFPassConfig(BPFTargetMachine &TM, PassManagerBase &PM)
70       : TargetPassConfig(TM, PM) {}
71 
72   BPFTargetMachine &getBPFTargetMachine() const {
73     return getTM<BPFTargetMachine>();
74   }
75 
76   bool addInstSelector() override;
77 };
78 }
79 
80 TargetPassConfig *BPFTargetMachine::createPassConfig(PassManagerBase &PM) {
81   return new BPFPassConfig(*this, PM);
82 }
83 
84 // Install an instruction selector pass using
85 // the ISelDag to gen BPF code.
86 bool BPFPassConfig::addInstSelector() {
87   addPass(createBPFISelDag(getBPFTargetMachine()));
88 
89   return false;
90 }
91