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      1 //===-- BPFInstPrinter.cpp - Convert BPF MCInst to asm syntax -------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This class prints an BPF MCInst to a .s file.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "BPF.h"
     15 #include "BPFInstPrinter.h"
     16 #include "llvm/MC/MCAsmInfo.h"
     17 #include "llvm/MC/MCExpr.h"
     18 #include "llvm/MC/MCInst.h"
     19 #include "llvm/MC/MCSymbol.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 
     29 void BPFInstPrinter::printInst(const MCInst *MI, raw_ostream &O,
     30                                StringRef Annot, const MCSubtargetInfo &STI) {
     31   printInstruction(MI, O);
     32   printAnnotation(O, Annot);
     33 }
     34 
     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 
     52 void BPFInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
     53                                   raw_ostream &O, const char *Modifier) {
     54   assert((Modifier == 0 || 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 << (int32_t)Op.getImm();
     60   } else {
     61     assert(Op.isExpr() && "Expected an expression");
     62     printExpr(Op.getExpr(), O);
     63   }
     64 }
     65 
     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   // offset
     71   if (OffsetOp.isImm())
     72     O << formatDec(OffsetOp.getImm());
     73   else
     74     assert(0 && "Expected an immediate");
     75 
     76   // register
     77   assert(RegOp.isReg() && "Register operand not a register");
     78   O << '(' << getRegisterName(RegOp.getReg()) << ')';
     79 }
     80 
     81 void BPFInstPrinter::printImm64Operand(const MCInst *MI, unsigned OpNo,
     82                                        raw_ostream &O) {
     83   const MCOperand &Op = MI->getOperand(OpNo);
     84   if (Op.isImm())
     85     O << (uint64_t)Op.getImm();
     86   else
     87     O << Op;
     88 }
     89