lib/MC/MCAsmInfo.cpp

   1 //===- MCAsmInfo.cpp - Asm Info -------------------------------------------===//
   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 file defines target asm properties related what form asm statements
  10 // should take.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/MC/MCAsmInfo.h"
  15 #include "llvm/BinaryFormat/Dwarf.h"
  16 #include "llvm/MC/MCContext.h"
  17 #include "llvm/MC/MCExpr.h"
  18 #include "llvm/MC/MCStreamer.h"
  19 #include "llvm/Support/CommandLine.h"
  20
  21 using namespace llvm;
  22
  23 enum DefaultOnOff { Default, Enable, Disable };
  24 static cl::opt<DefaultOnOff> DwarfExtendedLoc(
  25     "dwarf-extended-loc", cl::Hidden,
  26     cl::desc("Disable emission of the extended flags in .loc directives."),
  27     cl::values(clEnumVal(Default, "Default for platform"),
  28                clEnumVal(Enable, "Enabled"), clEnumVal(Disable, "Disabled")),
  29     cl::init(Default));
  30
  31 MCAsmInfo::MCAsmInfo() {
  32   SeparatorString = ";";
  33   CommentString = "#";
  34   LabelSuffix = ":";
  35   PrivateGlobalPrefix = "L";
  36   PrivateLabelPrefix = PrivateGlobalPrefix;
  37   LinkerPrivateGlobalPrefix = "";
  38   InlineAsmStart = "APP";
  39   InlineAsmEnd = "NO_APP";
  40   Code16Directive = ".code16";
  41   Code32Directive = ".code32";
  42   Code64Directive = ".code64";
  43   ZeroDirective = "\t.zero\t";
  44   AsciiDirective = "\t.ascii\t";
  45   AscizDirective = "\t.asciz\t";
  46   Data8bitsDirective = "\t.byte\t";
  47   Data16bitsDirective = "\t.short\t";
  48   Data32bitsDirective = "\t.long\t";
  49   Data64bitsDirective = "\t.quad\t";
  50   GlobalDirective = "\t.globl\t";
  51   WeakDirective = "\t.weak\t";
  52   if (DwarfExtendedLoc != Default)
  53     SupportsExtendedDwarfLocDirective = DwarfExtendedLoc == Enable;
  54
  55   // FIXME: Clang's logic should be synced with the logic used to initialize
  56   //        this member and the two implementations should be merged.
  57   // For reference:
  58   // - Solaris always enables the integrated assembler by default
  59   //   - SparcELFMCAsmInfo and X86ELFMCAsmInfo are handling this case
  60   // - Windows always enables the integrated assembler by default
  61   //   - MCAsmInfoCOFF is handling this case, should it be MCAsmInfoMicrosoft?
  62   // - MachO targets always enables the integrated assembler by default
  63   //   - MCAsmInfoDarwin is handling this case
  64   // - Generic_GCC toolchains enable the integrated assembler on a per
  65   //   architecture basis.
  66   //   - The target subclasses for AArch64, ARM, and X86 handle these cases
  67   UseIntegratedAssembler = false;
  68   PreserveAsmComments = true;
  69 }
  70
  71 MCAsmInfo::~MCAsmInfo() = default;
  72
  73 bool MCAsmInfo::isSectionAtomizableBySymbols(const MCSection &Section) const {
  74   return false;
  75 }
  76
  77 const MCExpr *
  78 MCAsmInfo::getExprForPersonalitySymbol(const MCSymbol *Sym,
  79                                        unsigned Encoding,
  80                                        MCStreamer &Streamer) const {
  81   return getExprForFDESymbol(Sym, Encoding, Streamer);
  82 }
  83
  84 const MCExpr *
  85 MCAsmInfo::getExprForFDESymbol(const MCSymbol *Sym,
  86                                unsigned Encoding,
  87                                MCStreamer &Streamer) const {
  88   if (!(Encoding & dwarf::DW_EH_PE_pcrel))
  89     return MCSymbolRefExpr::create(Sym, Streamer.getContext());
  90
  91   MCContext &Context = Streamer.getContext();
  92   const MCExpr *Res = MCSymbolRefExpr::create(Sym, Context);
  93   MCSymbol *PCSym = Context.createTempSymbol();
  94   Streamer.EmitLabel(PCSym);
  95   const MCExpr *PC = MCSymbolRefExpr::create(PCSym, Context);
  96   return MCBinaryExpr::createSub(Res, PC, Context);
  97 }
  98
  99 static bool isAcceptableChar(char C) {
 100   return (C >= 'a' && C <= 'z') || (C >= 'A' && C <= 'Z') ||
 101          (C >= '0' && C <= '9') || C == '_' || C == '$' || C == '.' || C == '@';
 102 }
 103
 104 bool MCAsmInfo::isValidUnquotedName(StringRef Name) const {
 105   if (Name.empty())
 106     return false;
 107
 108   // If any of the characters in the string is an unacceptable character, force
 109   // quotes.
 110   for (char C : Name) {
 111     if (!isAcceptableChar(C))
 112       return false;
 113   }
 114
 115   return true;
 116 }
 117
 118 bool MCAsmInfo::shouldOmitSectionDirective(StringRef SectionName) const {
 119   // FIXME: Does .section .bss/.data/.text work everywhere??
 120   return SectionName == ".text" || SectionName == ".data" ||
 121         (SectionName == ".bss" && !usesELFSectionDirectiveForBSS());
 122 }