1 //===-- BPFAsmPrinter.cpp - BPF LLVM assembly writer ----------------------===//
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 // This file contains a printer that converts from our internal representation
11 // of machine-dependent LLVM code to the BPF assembly language.
12 //
13 //===----------------------------------------------------------------------===//
14
15 #include "BPF.h"
16 #include "BPFInstrInfo.h"
17 #include "BPFMCInstLower.h"
18 #include "BPFTargetMachine.h"
19 #include "BTFDebug.h"
20 #include "InstPrinter/BPFInstPrinter.h"
21 #include "llvm/CodeGen/AsmPrinter.h"
22 #include "llvm/CodeGen/MachineConstantPool.h"
23 #include "llvm/CodeGen/MachineFunctionPass.h"
24 #include "llvm/CodeGen/MachineInstr.h"
25 #include "llvm/CodeGen/MachineModuleInfo.h"
26 #include "llvm/MC/MCAsmInfo.h"
27 #include "llvm/MC/MCInst.h"
28 #include "llvm/MC/MCStreamer.h"
29 #include "llvm/MC/MCSymbol.h"
30 #include "llvm/Support/TargetRegistry.h"
31 #include "llvm/Support/raw_ostream.h"
32 using namespace llvm;
33
34 #define DEBUG_TYPE "asm-printer"
35
36 namespace {
37 class BPFAsmPrinter : public AsmPrinter {
38 public:
BPFAsmPrinter(TargetMachine & TM,std::unique_ptr<MCStreamer> Streamer)39 explicit BPFAsmPrinter(TargetMachine &TM,
40 std::unique_ptr<MCStreamer> Streamer)
41 : AsmPrinter(TM, std::move(Streamer)) {}
42
getPassName() const43 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 unsigned AsmVariant, const char *ExtraCode,
48 raw_ostream &O) override;
49 bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
50 unsigned AsmVariant, const char *ExtraCode,
51 raw_ostream &O) override;
52
53 void EmitInstruction(const MachineInstr *MI) override;
54 };
55 } // namespace
56
doInitialization(Module & M)57 bool BPFAsmPrinter::doInitialization(Module &M) {
58 AsmPrinter::doInitialization(M);
59
60 if (MAI->doesSupportDebugInformation()) {
61 Handlers.push_back(HandlerInfo(new BTFDebug(this), "emit",
62 "Debug Info Emission", "BTF",
63 "BTF Emission"));
64 }
65
66 return false;
67 }
68
printOperand(const MachineInstr * MI,int OpNum,raw_ostream & O)69 void BPFAsmPrinter::printOperand(const MachineInstr *MI, int OpNum,
70 raw_ostream &O) {
71 const MachineOperand &MO = MI->getOperand(OpNum);
72
73 switch (MO.getType()) {
74 case MachineOperand::MO_Register:
75 O << BPFInstPrinter::getRegisterName(MO.getReg());
76 break;
77
78 case MachineOperand::MO_Immediate:
79 O << MO.getImm();
80 break;
81
82 case MachineOperand::MO_MachineBasicBlock:
83 O << *MO.getMBB()->getSymbol();
84 break;
85
86 case MachineOperand::MO_GlobalAddress:
87 O << *getSymbol(MO.getGlobal());
88 break;
89
90 case MachineOperand::MO_BlockAddress: {
91 MCSymbol *BA = GetBlockAddressSymbol(MO.getBlockAddress());
92 O << BA->getName();
93 break;
94 }
95
96 case MachineOperand::MO_ExternalSymbol:
97 O << *GetExternalSymbolSymbol(MO.getSymbolName());
98 break;
99
100 case MachineOperand::MO_JumpTableIndex:
101 case MachineOperand::MO_ConstantPoolIndex:
102 default:
103 llvm_unreachable("<unknown operand type>");
104 }
105 }
106
PrintAsmOperand(const MachineInstr * MI,unsigned OpNo,unsigned,const char * ExtraCode,raw_ostream & O)107 bool BPFAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
108 unsigned /*AsmVariant*/,
109 const char *ExtraCode, raw_ostream &O) {
110 if (ExtraCode && ExtraCode[0])
111 return true; // BPF does not have special modifiers
112
113 printOperand(MI, OpNo, O);
114 return false;
115 }
116
PrintAsmMemoryOperand(const MachineInstr * MI,unsigned OpNum,unsigned AsmVariant,const char * ExtraCode,raw_ostream & O)117 bool BPFAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
118 unsigned OpNum, unsigned AsmVariant,
119 const char *ExtraCode,
120 raw_ostream &O) {
121 assert(OpNum + 1 < MI->getNumOperands() && "Insufficient operands");
122 const MachineOperand &BaseMO = MI->getOperand(OpNum);
123 const MachineOperand &OffsetMO = MI->getOperand(OpNum + 1);
124 assert(BaseMO.isReg() && "Unexpected base pointer for inline asm memory operand.");
125 assert(OffsetMO.isImm() && "Unexpected offset for inline asm memory operand.");
126 int Offset = OffsetMO.getImm();
127
128 if (ExtraCode)
129 return true; // Unknown modifier.
130
131 if (Offset < 0)
132 O << "(" << BPFInstPrinter::getRegisterName(BaseMO.getReg()) << " - " << -Offset << ")";
133 else
134 O << "(" << BPFInstPrinter::getRegisterName(BaseMO.getReg()) << " + " << Offset << ")";
135
136 return false;
137 }
138
EmitInstruction(const MachineInstr * MI)139 void BPFAsmPrinter::EmitInstruction(const MachineInstr *MI) {
140
141 BPFMCInstLower MCInstLowering(OutContext, *this);
142
143 MCInst TmpInst;
144 MCInstLowering.Lower(MI, TmpInst);
145 EmitToStreamer(*OutStreamer, TmpInst);
146 }
147
148 // Force static initialization.
LLVMInitializeBPFAsmPrinter()149 extern "C" void LLVMInitializeBPFAsmPrinter() {
150 RegisterAsmPrinter<BPFAsmPrinter> X(getTheBPFleTarget());
151 RegisterAsmPrinter<BPFAsmPrinter> Y(getTheBPFbeTarget());
152 RegisterAsmPrinter<BPFAsmPrinter> Z(getTheBPFTarget());
153 }
154