1 //===-- BPFInstPrinter.cpp - Convert BPF MCInst to asm syntax -------------===//
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 class prints an BPF MCInst to a .s file.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "MCTargetDesc/BPFInstPrinter.h"
14 #include "llvm/MC/MCAsmInfo.h"
15 #include "llvm/MC/MCExpr.h"
16 #include "llvm/MC/MCInst.h"
17 #include "llvm/MC/MCRegister.h"
18 #include "llvm/MC/MCSymbol.h"
19 #include "llvm/Support/Casting.h"
20 #include "llvm/Support/ErrorHandling.h"
21 #include "llvm/Support/FormattedStream.h"
22 using namespace llvm;
23
24 #define DEBUG_TYPE "asm-printer"
25
26 // Include the auto-generated portion of the assembly writer.
27 #include "BPFGenAsmWriter.inc"
28
printInst(const MCInst * MI,uint64_t Address,StringRef Annot,const MCSubtargetInfo & STI,raw_ostream & O)29 void BPFInstPrinter::printInst(const MCInst *MI, uint64_t Address,
30 StringRef Annot, const MCSubtargetInfo &STI,
31 raw_ostream &O) {
32 printInstruction(MI, Address, O);
33 printAnnotation(O, Annot);
34 }
35
printExpr(const MCExpr * Expr,raw_ostream & O)36 static void printExpr(const MCExpr *Expr, raw_ostream &O) {
37 #ifndef NDEBUG
38 const MCSymbolRefExpr *SRE;
39
40 if (const MCBinaryExpr *BE = dyn_cast<MCBinaryExpr>(Expr))
41 SRE = dyn_cast<MCSymbolRefExpr>(BE->getLHS());
42 else
43 SRE = dyn_cast<MCSymbolRefExpr>(Expr);
44 assert(SRE && "Unexpected MCExpr type.");
45
46 MCSymbolRefExpr::VariantKind Kind = SRE->getKind();
47
48 assert(Kind == MCSymbolRefExpr::VK_None);
49 #endif
50 O << *Expr;
51 }
52
printOperand(const MCInst * MI,unsigned OpNo,raw_ostream & O,const char * Modifier)53 void BPFInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
54 raw_ostream &O, const char *Modifier) {
55 assert((Modifier == nullptr || Modifier[0] == 0) && "No modifiers supported");
56 const MCOperand &Op = MI->getOperand(OpNo);
57 if (Op.isReg()) {
58 O << getRegisterName(Op.getReg());
59 } else if (Op.isImm()) {
60 O << formatImm((int32_t)Op.getImm());
61 } else {
62 assert(Op.isExpr() && "Expected an expression");
63 printExpr(Op.getExpr(), O);
64 }
65 }
66
printMemOperand(const MCInst * MI,int OpNo,raw_ostream & O,const char * Modifier)67 void BPFInstPrinter::printMemOperand(const MCInst *MI, int OpNo, raw_ostream &O,
68 const char *Modifier) {
69 const MCOperand &RegOp = MI->getOperand(OpNo);
70 const MCOperand &OffsetOp = MI->getOperand(OpNo + 1);
71
72 // register
73 assert(RegOp.isReg() && "Register operand not a register");
74 O << getRegisterName(RegOp.getReg());
75
76 // offset
77 if (OffsetOp.isImm()) {
78 auto Imm = OffsetOp.getImm();
79 if (Imm >= 0)
80 O << " + " << formatImm(Imm);
81 else
82 O << " - " << formatImm(-Imm);
83 } else {
84 assert(0 && "Expected an immediate");
85 }
86 }
87
printImm64Operand(const MCInst * MI,unsigned OpNo,raw_ostream & O)88 void BPFInstPrinter::printImm64Operand(const MCInst *MI, unsigned OpNo,
89 raw_ostream &O) {
90 const MCOperand &Op = MI->getOperand(OpNo);
91 if (Op.isImm())
92 O << formatImm(Op.getImm());
93 else if (Op.isExpr())
94 printExpr(Op.getExpr(), O);
95 else
96 O << Op;
97 }
98
printBrTargetOperand(const MCInst * MI,unsigned OpNo,raw_ostream & O)99 void BPFInstPrinter::printBrTargetOperand(const MCInst *MI, unsigned OpNo,
100 raw_ostream &O) {
101 const MCOperand &Op = MI->getOperand(OpNo);
102 if (Op.isImm()) {
103 int16_t Imm = Op.getImm();
104 O << ((Imm >= 0) ? "+" : "") << formatImm(Imm);
105 } else if (Op.isExpr()) {
106 printExpr(Op.getExpr(), O);
107 } else {
108 O << Op;
109 }
110 }
111