LLVM  16.0.0git
BPFMCInstLower.cpp
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1 //=-- BPFMCInstLower.cpp - Convert BPF MachineInstr to an MCInst ------------=//
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 // This file contains code to lower BPF MachineInstrs to their corresponding
10 // MCInst records.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "BPFMCInstLower.h"
18 #include "llvm/MC/MCAsmInfo.h"
19 #include "llvm/MC/MCContext.h"
20 #include "llvm/MC/MCExpr.h"
21 #include "llvm/MC/MCInst.h"
24 using namespace llvm;
25 
26 MCSymbol *
28  return Printer.getSymbol(MO.getGlobal());
29 }
30 
31 MCSymbol *
33  return Printer.GetExternalSymbolSymbol(MO.getSymbolName());
34 }
35 
37  MCSymbol *Sym) const {
38 
39  const MCExpr *Expr = MCSymbolRefExpr::create(Sym, Ctx);
40 
41  if (!MO.isJTI() && MO.getOffset())
42  llvm_unreachable("unknown symbol op");
43 
44  return MCOperand::createExpr(Expr);
45 }
46 
47 void BPFMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
48  OutMI.setOpcode(MI->getOpcode());
49 
50  for (const MachineOperand &MO : MI->operands()) {
51  MCOperand MCOp;
52  switch (MO.getType()) {
53  default:
54  MI->print(errs());
55  llvm_unreachable("unknown operand type");
57  // Ignore all implicit register operands.
58  if (MO.isImplicit())
59  continue;
60  MCOp = MCOperand::createReg(MO.getReg());
61  break;
63  MCOp = MCOperand::createImm(MO.getImm());
64  break;
66  MCOp = MCOperand::createExpr(
67  MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), Ctx));
68  break;
70  continue;
73  break;
76  break;
77  }
78 
79  OutMI.addOperand(MCOp);
80  }
81 }
AsmPrinter.h
MI
IRTranslator LLVM IR MI
Definition: IRTranslator.cpp:108
MachineInstr.h
llvm::MachineOperand::MO_Immediate
@ MO_Immediate
Immediate operand.
Definition: MachineOperand.h:52
llvm
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
llvm::MCSymbol
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:41
llvm::MCOperand::createExpr
static MCOperand createExpr(const MCExpr *Val)
Definition: MCInst.h:162
llvm::MachineOperand::getGlobal
const GlobalValue * getGlobal() const
Definition: MachineOperand.h:572
llvm::MCOperand::createImm
static MCOperand createImm(int64_t Val)
Definition: MCInst.h:141
ErrorHandling.h
MachineBasicBlock.h
llvm::MachineOperand::isJTI
bool isJTI() const
isJTI - Tests if this is a MO_JumpTableIndex operand.
Definition: MachineOperand.h:336
BPFMCInstLower.h
llvm::errs
raw_fd_ostream & errs()
This returns a reference to a raw_ostream for standard error.
Definition: raw_ostream.cpp:891
llvm::MCInst
Instances of this class represent a single low-level machine instruction.
Definition: MCInst.h:184
llvm::MachineOperand::getOffset
int64_t getOffset() const
Return the offset from the symbol in this operand.
Definition: MachineOperand.h:609
llvm::MachineOperand::MO_Register
@ MO_Register
Register operand.
Definition: MachineOperand.h:51
llvm::MCInst::setOpcode
void setOpcode(unsigned Op)
Definition: MCInst.h:197
llvm::BPFMCInstLower::LowerSymbolOperand
MCOperand LowerSymbolOperand(const MachineOperand &MO, MCSymbol *Sym) const
Definition: BPFMCInstLower.cpp:36
llvm::MachineOperand::MO_GlobalAddress
@ MO_GlobalAddress
Address of a global value.
Definition: MachineOperand.h:61
MCContext.h
MCInst.h
llvm::MachineOperand
MachineOperand class - Representation of each machine instruction operand.
Definition: MachineOperand.h:48
llvm::BPFMCInstLower::GetGlobalAddressSymbol
MCSymbol * GetGlobalAddressSymbol(const MachineOperand &MO) const
Definition: BPFMCInstLower.cpp:27
llvm::MCInst::addOperand
void addOperand(const MCOperand Op)
Definition: MCInst.h:210
llvm::Pass::print
virtual void print(raw_ostream &OS, const Module *M) const
print - Print out the internal state of the pass.
Definition: Pass.cpp:130
llvm::BPFMCInstLower::GetExternalSymbolSymbol
MCSymbol * GetExternalSymbolSymbol(const MachineOperand &MO) const
Definition: BPFMCInstLower.cpp:32
llvm::MachineInstr
Representation of each machine instruction.
Definition: MachineInstr.h:66
llvm::AsmPrinter::getSymbol
MCSymbol * getSymbol(const GlobalValue *GV) const
Definition: AsmPrinter.cpp:656
llvm::AsmPrinter::GetExternalSymbolSymbol
MCSymbol * GetExternalSymbolSymbol(StringRef Sym) const
Return the MCSymbol for the specified ExternalSymbol.
Definition: AsmPrinter.cpp:3596
llvm::BPFMCInstLower::Lower
void Lower(const MachineInstr *MI, MCInst &OutMI) const
Definition: BPFMCInstLower.cpp:47
MCAsmInfo.h
llvm_unreachable
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
Definition: ErrorHandling.h:143
llvm::MCOperand::createReg
static MCOperand createReg(unsigned Reg)
Definition: MCInst.h:134
llvm::MachineOperand::MO_MachineBasicBlock
@ MO_MachineBasicBlock
MachineBasicBlock reference.
Definition: MachineOperand.h:55
llvm::MachineOperand::MO_ExternalSymbol
@ MO_ExternalSymbol
Name of external global symbol.
Definition: MachineOperand.h:60
llvm::MCSymbolRefExpr::create
static const MCSymbolRefExpr * create(const MCSymbol *Symbol, MCContext &Ctx)
Definition: MCExpr.h:386
llvm::MachineOperand::getSymbolName
const char * getSymbolName() const
Definition: MachineOperand.h:617
llvm::MCOperand
Instances of this class represent operands of the MCInst class.
Definition: MCInst.h:36
llvm::MachineOperand::MO_RegisterMask
@ MO_RegisterMask
Mask of preserved registers.
Definition: MachineOperand.h:63
raw_ostream.h
MCExpr.h
llvm::MCExpr
Base class for the full range of assembler expressions which are needed for parsing.
Definition: MCExpr.h:35