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 "BPF.h"
15 #include "BPFTargetMachine.h"
16 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
17 #include "llvm/IR/LegacyPassManager.h"
18 #include "llvm/CodeGen/Passes.h"
19 #include "llvm/Support/FormattedStream.h"
20 #include "llvm/Support/TargetRegistry.h"
21 #include "llvm/Target/TargetOptions.h"
22 using namespace llvm;
23 
24 extern "C" void LLVMInitializeBPFTarget() {
25   // Register the target.
26   RegisterTargetMachine<BPFTargetMachine> X(TheBPFTarget);
27 }
28 
29 // DataLayout --> Little-endian, 64-bit pointer/ABI/alignment
30 // The stack is always 8 byte aligned
31 // On function prologue, the stack is created by decrementing
32 // its pointer. Once decremented, all references are done with positive
33 // offset from the stack/frame pointer.
34 BPFTargetMachine::BPFTargetMachine(const Target &T, StringRef TT, StringRef CPU,
35                                    StringRef FS, const TargetOptions &Options,
36                                    Reloc::Model RM, CodeModel::Model CM,
37                                    CodeGenOpt::Level OL)
38     : LLVMTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL),
39       TLOF(make_unique<TargetLoweringObjectFileELF>()),
40       DL("e-m:e-p:64:64-i64:64-n32:64-S128"),
41       Subtarget(TT, CPU, FS, *this) {
42   initAsmInfo();
43 }
44 namespace {
45 // BPF Code Generator Pass Configuration Options.
46 class BPFPassConfig : public TargetPassConfig {
47 public:
48   BPFPassConfig(BPFTargetMachine *TM, PassManagerBase &PM)
49       : TargetPassConfig(TM, PM) {}
50 
51   BPFTargetMachine &getBPFTargetMachine() const {
52     return getTM<BPFTargetMachine>();
53   }
54 
55   bool addInstSelector() override;
56 };
57 }
58 
59 TargetPassConfig *BPFTargetMachine::createPassConfig(PassManagerBase &PM) {
60   return new BPFPassConfig(this, PM);
61 }
62 
63 // Install an instruction selector pass using
64 // the ISelDag to gen BPF code.
65 bool BPFPassConfig::addInstSelector() {
66   addPass(createBPFISelDag(getBPFTargetMachine()));
67 
68   return false;
69 }
70