1//===-- BPFAsmPrinter.cpp - BPF LLVM assembly writer ----------------------===//
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 a printer that converts from our internal representation
10// of machine-dependent LLVM code to the BPF assembly language.
11//
12//===----------------------------------------------------------------------===//
13
14#include "BPF.h"
15#include "BPFInstrInfo.h"
16#include "BPFMCInstLower.h"
17#include "BTFDebug.h"
18#include "MCTargetDesc/BPFInstPrinter.h"
19#include "TargetInfo/BPFTargetInfo.h"
20#include "llvm/CodeGen/AsmPrinter.h"
21#include "llvm/CodeGen/MachineConstantPool.h"
22#include "llvm/CodeGen/MachineInstr.h"
23#include "llvm/CodeGen/MachineModuleInfo.h"
24#include "llvm/IR/Module.h"
25#include "llvm/MC/MCAsmInfo.h"
26#include "llvm/MC/MCInst.h"
27#include "llvm/MC/MCStreamer.h"
28#include "llvm/MC/MCSymbol.h"
29#include "llvm/MC/TargetRegistry.h"
30#include "llvm/Support/Compiler.h"
31#include "llvm/Support/raw_ostream.h"
32using namespace llvm;
33
34#define DEBUG_TYPE "asm-printer"
35
36namespace {
37class BPFAsmPrinter : public AsmPrinter {
38public:
39 explicit BPFAsmPrinter(TargetMachine &TM,
40 std::unique_ptr<MCStreamer> Streamer)
41 : AsmPrinter(TM, std::move(Streamer), ID), BTF(nullptr) {}
42
43 StringRef getPassName() const override { return "BPF Assembly Printer"; }
44 bool doInitialization(Module &M) override;
45 void printOperand(const MachineInstr *MI, int OpNum, raw_ostream &O);
46 bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
47 const char *ExtraCode, raw_ostream &O) override;
48 bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
49 const char *ExtraCode, raw_ostream &O) override;
50
51 void emitInstruction(const MachineInstr *MI) override;
52
53 static char ID;
54
55private:
56 BTFDebug *BTF;
57};
58} // namespace
59
60bool BPFAsmPrinter::doInitialization(Module &M) {
61 AsmPrinter::doInitialization(M);
62
63 // Only emit BTF when debuginfo available.
64 if (MAI->doesSupportDebugInformation() && !M.debug_compile_units().empty()) {
65 BTF = new BTFDebug(this);
66 Handlers.push_back(Elt: std::unique_ptr<BTFDebug>(BTF));
67 }
68
69 return false;
70}
71
72void BPFAsmPrinter::printOperand(const MachineInstr *MI, int OpNum,
73 raw_ostream &O) {
74 const MachineOperand &MO = MI->getOperand(i: OpNum);
75
76 switch (MO.getType()) {
77 case MachineOperand::MO_Register:
78 O << BPFInstPrinter::getRegisterName(Reg: MO.getReg());
79 break;
80
81 case MachineOperand::MO_Immediate:
82 O << MO.getImm();
83 break;
84
85 case MachineOperand::MO_MachineBasicBlock:
86 O << *MO.getMBB()->getSymbol();
87 break;
88
89 case MachineOperand::MO_GlobalAddress:
90 O << *getSymbol(GV: MO.getGlobal());
91 break;
92
93 case MachineOperand::MO_BlockAddress: {
94 MCSymbol *BA = GetBlockAddressSymbol(BA: MO.getBlockAddress());
95 O << BA->getName();
96 break;
97 }
98
99 case MachineOperand::MO_ExternalSymbol:
100 O << *GetExternalSymbolSymbol(Sym: MO.getSymbolName());
101 break;
102
103 case MachineOperand::MO_JumpTableIndex:
104 case MachineOperand::MO_ConstantPoolIndex:
105 default:
106 llvm_unreachable("<unknown operand type>");
107 }
108}
109
110bool BPFAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
111 const char *ExtraCode, raw_ostream &O) {
112 if (ExtraCode && ExtraCode[0])
113 return AsmPrinter::PrintAsmOperand(MI, OpNo, ExtraCode, OS&: O);
114
115 printOperand(MI, OpNum: OpNo, O);
116 return false;
117}
118
119bool BPFAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
120 unsigned OpNum, const char *ExtraCode,
121 raw_ostream &O) {
122 assert(OpNum + 1 < MI->getNumOperands() && "Insufficient operands");
123 const MachineOperand &BaseMO = MI->getOperand(i: OpNum);
124 const MachineOperand &OffsetMO = MI->getOperand(i: OpNum + 1);
125 assert(BaseMO.isReg() && "Unexpected base pointer for inline asm memory operand.");
126 assert(OffsetMO.isImm() && "Unexpected offset for inline asm memory operand.");
127 int Offset = OffsetMO.getImm();
128
129 if (ExtraCode)
130 return true; // Unknown modifier.
131
132 if (Offset < 0)
133 O << "(" << BPFInstPrinter::getRegisterName(Reg: BaseMO.getReg()) << " - " << -Offset << ")";
134 else
135 O << "(" << BPFInstPrinter::getRegisterName(Reg: BaseMO.getReg()) << " + " << Offset << ")";
136
137 return false;
138}
139
140void BPFAsmPrinter::emitInstruction(const MachineInstr *MI) {
141 BPF_MC::verifyInstructionPredicates(Opcode: MI->getOpcode(),
142 Features: getSubtargetInfo().getFeatureBits());
143
144 MCInst TmpInst;
145
146 if (!BTF || !BTF->InstLower(MI, OutMI&: TmpInst)) {
147 BPFMCInstLower MCInstLowering(OutContext, *this);
148 MCInstLowering.Lower(MI, OutMI&: TmpInst);
149 }
150 EmitToStreamer(S&: *OutStreamer, Inst: TmpInst);
151}
152
153char BPFAsmPrinter::ID = 0;
154
155INITIALIZE_PASS(BPFAsmPrinter, "bpf-asm-printer", "BPF Assembly Printer", false,
156 false)
157
158// Force static initialization.
159extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void
160LLVMInitializeBPFAsmPrinter() {
161 RegisterAsmPrinter<BPFAsmPrinter> X(getTheBPFleTarget());
162 RegisterAsmPrinter<BPFAsmPrinter> Y(getTheBPFbeTarget());
163 RegisterAsmPrinter<BPFAsmPrinter> Z(getTheBPFTarget());
164}
165