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