lib/Target/BPF/MCTargetDesc/BPFInstPrinter.cpp

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