LLVM  12.0.0git
BPFTargetMachine.cpp
Go to the documentation of this file.
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"
17 #include "llvm/CodeGen/Passes.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 
31  // Register the target.
35 
41 }
42 
43 // DataLayout: little or big endian
44 static std::string computeDataLayout(const Triple &TT) {
45  if (TT.getArch() == Triple::bpfeb)
46  return "E-m:e-p:64:64-i64:64-i128:128-n32:64-S128";
47  else
48  return "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128";
49 }
50 
52  if (!RM.hasValue())
53  return Reloc::PIC_;
54  return *RM;
55 }
56 
58  StringRef CPU, StringRef FS,
59  const TargetOptions &Options,
62  CodeGenOpt::Level OL, bool JIT)
63  : LLVMTargetMachine(T, computeDataLayout(TT), TT, CPU, FS, Options,
65  getEffectiveCodeModel(CM, CodeModel::Small), OL),
66  TLOF(std::make_unique<TargetLoweringObjectFileELF>()),
67  Subtarget(TT, std::string(CPU), std::string(FS), *this) {
68  initAsmInfo();
69 
70  BPFMCAsmInfo *MAI =
71  static_cast<BPFMCAsmInfo *>(const_cast<MCAsmInfo *>(AsmInfo.get()));
73 }
74 
75 namespace {
76 // BPF Code Generator Pass Configuration Options.
77 class BPFPassConfig : public TargetPassConfig {
78 public:
79  BPFPassConfig(BPFTargetMachine &TM, PassManagerBase &PM)
80  : TargetPassConfig(TM, PM) {}
81 
82  BPFTargetMachine &getBPFTargetMachine() const {
83  return getTM<BPFTargetMachine>();
84  }
85 
86  void addIRPasses() override;
87  bool addInstSelector() override;
88  void addMachineSSAOptimization() override;
89  void addPreEmitPass() override;
90 };
91 }
92 
94  return new BPFPassConfig(*this, PM);
95 }
96 
97 void BPFPassConfig::addIRPasses() {
98 
99  addPass(createBPFAbstractMemberAccess(&getBPFTargetMachine()));
100  addPass(createBPFPreserveDIType());
101 
103 }
104 
105 // Install an instruction selector pass using
106 // the ISelDag to gen BPF code.
107 bool BPFPassConfig::addInstSelector() {
108  addPass(createBPFISelDag(getBPFTargetMachine()));
109 
110  return false;
111 }
112 
113 void BPFPassConfig::addMachineSSAOptimization() {
115 
116  // The default implementation must be called first as we want eBPF
117  // Peephole ran at last.
119 
120  const BPFSubtarget *Subtarget = getBPFTargetMachine().getSubtargetImpl();
121  if (!DisableMIPeephole) {
122  if (Subtarget->getHasAlu32())
123  addPass(createBPFMIPeepholePass());
125  }
126 }
127 
128 void BPFPassConfig::addPreEmitPass() {
130  if (getOptLevel() != CodeGenOpt::None)
131  if (!DisableMIPeephole)
133 }
static GCMetadataPrinterRegistry::Add< ErlangGCPrinter > X("erlang", "erlang-compatible garbage collector")
CodeModel::Model getEffectiveCodeModel(Optional< CodeModel::Model > CM, CodeModel::Model Default)
Helper method for getting the code model, returning Default if CM does not have a value...
static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
void initializeBPFMIPeepholePass(PassRegistry &)
This class represents lattice values for constants.
Definition: AllocatorList.h:23
LLVM_EXTERNAL_VISIBILITY void LLVMInitializeBPFTarget()
FunctionPass * createBPFMIPreEmitPeepholePass()
virtual void addIRPasses()
Add common target configurable passes that perform LLVM IR to IR transforms following machine indepen...
FunctionPass * createBPFMISimplifyPatchablePass()
void initializeBPFPreserveDITypePass(PassRegistry &)
FunctionPass * createBPFMIPreEmitCheckingPass()
virtual void addMachineSSAOptimization()
addMachineSSAOptimization - Add standard passes that optimize machine instructions in SSA form...
static GCMetadataPrinterRegistry::Add< OcamlGCMetadataPrinter > Y("ocaml", "ocaml 3.10-compatible collector")
Definition: BitVector.h:959
void setDwarfUsesRelocationsAcrossSections(bool enable)
Definition: BPFMCAsmInfo.h:48
Target-Independent Code Generator Pass Configuration Options.
TargetPassConfig * createPassConfig(PassManagerBase &PM) override
Create a pass configuration object to be used by addPassToEmitX methods for generating a pipeline of ...
void initializeBPFAbstractMemberAccessPass(PassRegistry &)
RegisterTargetMachine - Helper template for registering a target machine implementation, for use in the target machine initialization function.
ArchType getArch() const
getArch - Get the parsed architecture type of this triple.
Definition: Triple.h:300
static cl::opt< bool > DisableMIPeephole("disable-bpf-peephole", cl::Hidden, cl::desc("Disable machine peepholes for BPF"))
This class is intended to be used as a base class for asm properties and features specific to the tar...
Definition: MCAsmInfo.h:56
bool getUseDwarfRIS() const
Definition: BPFSubtarget.h:74
ModulePass * createBPFAbstractMemberAccess(BPFTargetMachine *TM)
CodeGenOpt::Level getOptLevel() const
Returns the optimization level: None, Less, Default, or Aggressive.
static Reloc::Model getEffectiveRelocModel(Optional< Reloc::Model > RM)
std::unique_ptr< const MCAsmInfo > AsmInfo
Contains target specific asm information.
Definition: TargetMachine.h:93
This class describes a target machine that is implemented with the LLVM target-independent code gener...
FunctionPass * createBPFMIPeepholePass()
Triple - Helper class for working with autoconf configuration names.
Definition: Triple.h:45
PassManagerBase - An abstract interface to allow code to add passes to a pass manager without having ...
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)
#define LLVM_EXTERNAL_VISIBILITY
Definition: Compiler.h:131
void initializeBPFMIPeepholeTruncElimPass(PassRegistry &)
Target - Wrapper for Target specific information.
bool hasValue() const
Definition: Optional.h:259
bool getHasAlu32() const
Definition: BPFSubtarget.h:73
static std::string computeDataLayout(const Triple &TT)
Target & getTheBPFleTarget()
FunctionPass * createBPFMIPeepholeTruncElimPass()
ModulePass * createBPFPreserveDIType()
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:57
PassRegistry - This class manages the registration and intitialization of the pass subsystem as appli...
Definition: PassRegistry.h:38
Target & getTheBPFbeTarget()
FunctionPass * createBPFISelDag(BPFTargetMachine &TM)
Target & getTheBPFTarget()