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      1 //===-- MCAsmInfo.cpp - Asm Info -------------------------------------------==//
      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 file defines target asm properties related what form asm statements
     11 // should take.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "llvm/MC/MCAsmInfo.h"
     16 #include "llvm/MC/MCContext.h"
     17 #include "llvm/MC/MCExpr.h"
     18 #include "llvm/MC/MCStreamer.h"
     19 #include "llvm/Support/DataTypes.h"
     20 #include "llvm/Support/Dwarf.h"
     21 #include <cctype>
     22 #include <cstring>
     23 using namespace llvm;
     24 
     25 MCAsmInfo::MCAsmInfo() {
     26   PointerSize = 4;
     27   IsLittleEndian = true;
     28   StackGrowsUp = false;
     29   HasSubsectionsViaSymbols = false;
     30   HasMachoZeroFillDirective = false;
     31   HasMachoTBSSDirective = false;
     32   HasStaticCtorDtorReferenceInStaticMode = false;
     33   LinkerRequiresNonEmptyDwarfLines = false;
     34   MaxInstLength = 4;
     35   PCSymbol = "$";
     36   SeparatorString = ";";
     37   CommentColumn = 40;
     38   CommentString = "#";
     39   LabelSuffix = ":";
     40   GlobalPrefix = "";
     41   PrivateGlobalPrefix = ".";
     42   LinkerPrivateGlobalPrefix = "";
     43   InlineAsmStart = "APP";
     44   InlineAsmEnd = "NO_APP";
     45   Code16Directive = ".code16";
     46   Code32Directive = ".code32";
     47   Code64Directive = ".code64";
     48   AssemblerDialect = 0;
     49   AllowQuotesInName = false;
     50   AllowNameToStartWithDigit = false;
     51   AllowPeriodsInName = true;
     52   AllowUTF8 = true;
     53   UseDataRegionDirectives = false;
     54   ZeroDirective = "\t.zero\t";
     55   AsciiDirective = "\t.ascii\t";
     56   AscizDirective = "\t.asciz\t";
     57   Data8bitsDirective = "\t.byte\t";
     58   Data16bitsDirective = "\t.short\t";
     59   Data32bitsDirective = "\t.long\t";
     60   Data64bitsDirective = "\t.quad\t";
     61   SunStyleELFSectionSwitchSyntax = false;
     62   UsesELFSectionDirectiveForBSS = false;
     63   AlignDirective = "\t.align\t";
     64   AlignmentIsInBytes = true;
     65   TextAlignFillValue = 0;
     66   GPRel64Directive = 0;
     67   GPRel32Directive = 0;
     68   GlobalDirective = "\t.globl\t";
     69   HasSetDirective = true;
     70   HasAggressiveSymbolFolding = true;
     71   COMMDirectiveAlignmentIsInBytes = true;
     72   LCOMMDirectiveAlignmentType = LCOMM::NoAlignment;
     73   HasDotTypeDotSizeDirective = true;
     74   HasSingleParameterDotFile = true;
     75   HasNoDeadStrip = false;
     76   HasSymbolResolver = false;
     77   WeakRefDirective = 0;
     78   WeakDefDirective = 0;
     79   LinkOnceDirective = 0;
     80   HiddenVisibilityAttr = MCSA_Hidden;
     81   HiddenDeclarationVisibilityAttr = MCSA_Hidden;
     82   ProtectedVisibilityAttr = MCSA_Protected;
     83   HasLEB128 = false;
     84   SupportsDebugInformation = false;
     85   ExceptionsType = ExceptionHandling::None;
     86   DwarfUsesInlineInfoSection = false;
     87   DwarfSectionOffsetDirective = 0;
     88   DwarfUsesRelocationsAcrossSections = true;
     89   DwarfRegNumForCFI = false;
     90   HasMicrosoftFastStdCallMangling = false;
     91 }
     92 
     93 MCAsmInfo::~MCAsmInfo() {
     94 }
     95 
     96 
     97 unsigned MCAsmInfo::getULEB128Size(unsigned Value) {
     98   unsigned Size = 0;
     99   do {
    100     Value >>= 7;
    101     Size += sizeof(int8_t);
    102   } while (Value);
    103   return Size;
    104 }
    105 
    106 unsigned MCAsmInfo::getSLEB128Size(int Value) {
    107   unsigned Size = 0;
    108   int Sign = Value >> (8 * sizeof(Value) - 1);
    109   bool IsMore;
    110 
    111   do {
    112     unsigned Byte = Value & 0x7f;
    113     Value >>= 7;
    114     IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0;
    115     Size += sizeof(int8_t);
    116   } while (IsMore);
    117   return Size;
    118 }
    119 
    120 const MCExpr *
    121 MCAsmInfo::getExprForPersonalitySymbol(const MCSymbol *Sym,
    122                                        unsigned Encoding,
    123                                        MCStreamer &Streamer) const {
    124   return getExprForFDESymbol(Sym, Encoding, Streamer);
    125 }
    126 
    127 const MCExpr *
    128 MCAsmInfo::getExprForFDESymbol(const MCSymbol *Sym,
    129                                unsigned Encoding,
    130                                MCStreamer &Streamer) const {
    131   if (!(Encoding & dwarf::DW_EH_PE_pcrel))
    132     return MCSymbolRefExpr::Create(Sym, Streamer.getContext());
    133 
    134   MCContext &Context = Streamer.getContext();
    135   const MCExpr *Res = MCSymbolRefExpr::Create(Sym, Context);
    136   MCSymbol *PCSym = Context.CreateTempSymbol();
    137   Streamer.EmitLabel(PCSym);
    138   const MCExpr *PC = MCSymbolRefExpr::Create(PCSym, Context);
    139   return MCBinaryExpr::CreateSub(Res, PC, Context);
    140 }
    141