llvm/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, uint64_t Address,
  28                                StringRef Annot, const MCSubtargetInfo &STI,
  29                                raw_ostream &O) {
  30   printInstruction(MI, Address, O);
  31   printAnnotation(O, Annot);
  32 }
  33
  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
  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
  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
  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
  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 }