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//===-- BPFAsmPrinter.cpp - BPF LLVM assembly writer ----------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains a printer that converts from our internal representation
// of machine-dependent LLVM code to the BPF assembly language.
//
//===----------------------------------------------------------------------===//
#include "BPF.h"
#include "BPFInstrInfo.h"
#include "BPFMCInstLower.h"
#include "BPFTargetMachine.h"
#include "BTFDebug.h"
#include "MCTargetDesc/BPFInstPrinter.h"
#include "TargetInfo/BPFTargetInfo.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
#define DEBUG_TYPE "asm-printer"
namespace {
class BPFAsmPrinter : public AsmPrinter {
public:
explicit BPFAsmPrinter(TargetMachine &TM,
std::unique_ptr<MCStreamer> Streamer)
: AsmPrinter(TM, std::move(Streamer)), BTF(nullptr) {}
StringRef getPassName() const override { return "BPF Assembly Printer"; }
bool doInitialization(Module &M) override;
void printOperand(const MachineInstr *MI, int OpNum, raw_ostream &O);
bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
const char *ExtraCode, raw_ostream &O) override;
bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
const char *ExtraCode, raw_ostream &O) override;
void emitInstruction(const MachineInstr *MI) override;
private:
BTFDebug *BTF;
};
} // namespace
bool BPFAsmPrinter::doInitialization(Module &M) {
AsmPrinter::doInitialization(M);
// Only emit BTF when debuginfo available.
if (MAI->doesSupportDebugInformation() && !M.debug_compile_units().empty()) {
BTF = new BTFDebug(this);
Handlers.push_back(HandlerInfo(std::unique_ptr<BTFDebug>(BTF), "emit",
"Debug Info Emission", "BTF",
"BTF Emission"));
}
return false;
}
void BPFAsmPrinter::printOperand(const MachineInstr *MI, int OpNum,
raw_ostream &O) {
const MachineOperand &MO = MI->getOperand(OpNum);
switch (MO.getType()) {
case MachineOperand::MO_Register:
O << BPFInstPrinter::getRegisterName(MO.getReg());
break;
case MachineOperand::MO_Immediate:
O << MO.getImm();
break;
case MachineOperand::MO_MachineBasicBlock:
O << *MO.getMBB()->getSymbol();
break;
case MachineOperand::MO_GlobalAddress:
O << *getSymbol(MO.getGlobal());
break;
case MachineOperand::MO_BlockAddress: {
MCSymbol *BA = GetBlockAddressSymbol(MO.getBlockAddress());
O << BA->getName();
break;
}
case MachineOperand::MO_ExternalSymbol:
O << *GetExternalSymbolSymbol(MO.getSymbolName());
break;
case MachineOperand::MO_JumpTableIndex:
case MachineOperand::MO_ConstantPoolIndex:
default:
llvm_unreachable("<unknown operand type>");
}
}
bool BPFAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
const char *ExtraCode, raw_ostream &O) {
if (ExtraCode && ExtraCode[0])
return AsmPrinter::PrintAsmOperand(MI, OpNo, ExtraCode, O);
printOperand(MI, OpNo, O);
return false;
}
bool BPFAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
unsigned OpNum, const char *ExtraCode,
raw_ostream &O) {
assert(OpNum + 1 < MI->getNumOperands() && "Insufficient operands");
const MachineOperand &BaseMO = MI->getOperand(OpNum);
const MachineOperand &OffsetMO = MI->getOperand(OpNum + 1);
assert(BaseMO.isReg() && "Unexpected base pointer for inline asm memory operand.");
assert(OffsetMO.isImm() && "Unexpected offset for inline asm memory operand.");
int Offset = OffsetMO.getImm();
if (ExtraCode)
return true; // Unknown modifier.
if (Offset < 0)
O << "(" << BPFInstPrinter::getRegisterName(BaseMO.getReg()) << " - " << -Offset << ")";
else
O << "(" << BPFInstPrinter::getRegisterName(BaseMO.getReg()) << " + " << Offset << ")";
return false;
}
void BPFAsmPrinter::emitInstruction(const MachineInstr *MI) {
MCInst TmpInst;
if (!BTF || !BTF->InstLower(MI, TmpInst)) {
BPFMCInstLower MCInstLowering(OutContext, *this);
MCInstLowering.Lower(MI, TmpInst);
}
EmitToStreamer(*OutStreamer, TmpInst);
}
// Force static initialization.
extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeBPFAsmPrinter() {
RegisterAsmPrinter<BPFAsmPrinter> X(getTheBPFleTarget());
RegisterAsmPrinter<BPFAsmPrinter> Y(getTheBPFbeTarget());
RegisterAsmPrinter<BPFAsmPrinter> Z(getTheBPFTarget());
}
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