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      1 //===-- MipsMCExpr.cpp - Mips specific MC expression classes --------------===//
      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 #include "MipsMCExpr.h"
     11 #include "llvm/MC/MCAsmInfo.h"
     12 #include "llvm/MC/MCAssembler.h"
     13 #include "llvm/MC/MCContext.h"
     14 #include "llvm/MC/MCObjectStreamer.h"
     15 
     16 using namespace llvm;
     17 
     18 #define DEBUG_TYPE "mipsmcexpr"
     19 
     20 bool MipsMCExpr::isSupportedBinaryExpr(MCSymbolRefExpr::VariantKind VK,
     21                                        const MCBinaryExpr *BE) {
     22   switch (VK) {
     23   case MCSymbolRefExpr::VK_Mips_ABS_LO:
     24   case MCSymbolRefExpr::VK_Mips_ABS_HI:
     25   case MCSymbolRefExpr::VK_Mips_HIGHER:
     26   case MCSymbolRefExpr::VK_Mips_HIGHEST:
     27     break;
     28   default:
     29     return false;
     30   }
     31 
     32   // We support expressions of the form "(sym1 binop1 sym2) binop2 const",
     33   // where "binop2 const" is optional.
     34   if (isa<MCBinaryExpr>(BE->getLHS())) {
     35     if (!isa<MCConstantExpr>(BE->getRHS()))
     36       return false;
     37     BE = cast<MCBinaryExpr>(BE->getLHS());
     38   }
     39   return (isa<MCSymbolRefExpr>(BE->getLHS())
     40           && isa<MCSymbolRefExpr>(BE->getRHS()));
     41 }
     42 
     43 const MipsMCExpr*
     44 MipsMCExpr::create(MCSymbolRefExpr::VariantKind VK, const MCExpr *Expr,
     45                    MCContext &Ctx) {
     46   VariantKind Kind;
     47   switch (VK) {
     48   case MCSymbolRefExpr::VK_Mips_ABS_LO:
     49     Kind = VK_Mips_LO;
     50     break;
     51   case MCSymbolRefExpr::VK_Mips_ABS_HI:
     52     Kind = VK_Mips_HI;
     53     break;
     54   case MCSymbolRefExpr::VK_Mips_HIGHER:
     55     Kind = VK_Mips_HIGHER;
     56     break;
     57   case MCSymbolRefExpr::VK_Mips_HIGHEST:
     58     Kind = VK_Mips_HIGHEST;
     59     break;
     60   default:
     61     llvm_unreachable("Invalid kind!");
     62   }
     63 
     64   return new (Ctx) MipsMCExpr(Kind, Expr);
     65 }
     66 
     67 void MipsMCExpr::printImpl(raw_ostream &OS, const MCAsmInfo *MAI) const {
     68   switch (Kind) {
     69   default: llvm_unreachable("Invalid kind!");
     70   case VK_Mips_LO: OS << "%lo"; break;
     71   case VK_Mips_HI: OS << "%hi"; break;
     72   case VK_Mips_HIGHER: OS << "%higher"; break;
     73   case VK_Mips_HIGHEST: OS << "%highest"; break;
     74   }
     75 
     76   OS << '(';
     77   Expr->print(OS, MAI);
     78   OS << ')';
     79 }
     80 
     81 bool
     82 MipsMCExpr::evaluateAsRelocatableImpl(MCValue &Res,
     83                                       const MCAsmLayout *Layout,
     84                                       const MCFixup *Fixup) const {
     85   return getSubExpr()->evaluateAsRelocatable(Res, Layout, Fixup);
     86 }
     87 
     88 void MipsMCExpr::visitUsedExpr(MCStreamer &Streamer) const {
     89   Streamer.visitUsedExpr(*getSubExpr());
     90 }
     91