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