llvm/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/ADT/StringExtras.h"
  16 #include "llvm/BinaryFormat/Dwarf.h"
  17 #include "llvm/MC/MCContext.h"
  18 #include "llvm/MC/MCExpr.h"
  19 #include "llvm/MC/MCStreamer.h"
  20 #include "llvm/Support/CommandLine.h"
  21
  22 using namespace llvm;
  23
  24 namespace {
  25 enum DefaultOnOff { Default, Enable, Disable };
  26 }
  27 static cl::opt<DefaultOnOff> DwarfExtendedLoc(
  28     "dwarf-extended-loc", cl::Hidden,
  29     cl::desc("Disable emission of the extended flags in .loc directives."),
  30     cl::values(clEnumVal(Default, "Default for platform"),
  31                clEnumVal(Enable, "Enabled"), clEnumVal(Disable, "Disabled")),
  32     cl::init(Default));
  33
  34 namespace llvm {
  35 cl::opt<cl::boolOrDefault> UseLEB128Directives(
  36     "use-leb128-directives", cl::Hidden,
  37     cl::desc(
  38         "Disable the usage of LEB128 directives, and generate .byte instead."),
  39     cl::init(cl::BOU_UNSET));
  40 }
  41
  42 MCAsmInfo::MCAsmInfo() {
  43   SeparatorString = ";";
  44   CommentString = "#";
  45   LabelSuffix = ":";
  46   PrivateGlobalPrefix = "L";
  47   PrivateLabelPrefix = PrivateGlobalPrefix;
  48   LinkerPrivateGlobalPrefix = "";
  49   InlineAsmStart = "APP";
  50   InlineAsmEnd = "NO_APP";
  51   Code16Directive = ".code16";
  52   Code32Directive = ".code32";
  53   Code64Directive = ".code64";
  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   GlobalDirective = "\t.globl\t";
  62   WeakDirective = "\t.weak\t";
  63   if (DwarfExtendedLoc != Default)
  64     SupportsExtendedDwarfLocDirective = DwarfExtendedLoc == Enable;
  65   if (UseLEB128Directives != cl::BOU_UNSET)
  66     HasLEB128Directives = UseLEB128Directives == cl::BOU_TRUE;
  67   UseIntegratedAssembler = true;
  68   ParseInlineAsmUsingAsmParser = false;
  69   PreserveAsmComments = true;
  70 }
  71
  72 MCAsmInfo::~MCAsmInfo() = default;
  73
  74 void MCAsmInfo::addInitialFrameState(const MCCFIInstruction &Inst) {
  75   InitialFrameState.push_back(Inst);
  76 }
  77
  78 bool MCAsmInfo::isSectionAtomizableBySymbols(const MCSection &Section) const {
  79   return false;
  80 }
  81
  82 const MCExpr *
  83 MCAsmInfo::getExprForPersonalitySymbol(const MCSymbol *Sym,
  84                                        unsigned Encoding,
  85                                        MCStreamer &Streamer) const {
  86   return getExprForFDESymbol(Sym, Encoding, Streamer);
  87 }
  88
  89 const MCExpr *
  90 MCAsmInfo::getExprForFDESymbol(const MCSymbol *Sym,
  91                                unsigned Encoding,
  92                                MCStreamer &Streamer) const {
  93   if (!(Encoding & dwarf::DW_EH_PE_pcrel))
  94     return MCSymbolRefExpr::create(Sym, Streamer.getContext());
  95
  96   MCContext &Context = Streamer.getContext();
  97   const MCExpr *Res = MCSymbolRefExpr::create(Sym, Context);
  98   MCSymbol *PCSym = Context.createTempSymbol();
  99   Streamer.emitLabel(PCSym);
 100   const MCExpr *PC = MCSymbolRefExpr::create(PCSym, Context);
 101   return MCBinaryExpr::createSub(Res, PC, Context);
 102 }
 103
 104 bool MCAsmInfo::isAcceptableChar(char C) const {
 105   if (C == '@')
 106     return doesAllowAtInName();
 107
 108   return isAlnum(C) || C == '_' || C == '$' || C == '.';
 109 }
 110
 111 bool MCAsmInfo::isValidUnquotedName(StringRef Name) const {
 112   if (Name.empty())
 113     return false;
 114
 115   // If any of the characters in the string is an unacceptable character, force
 116   // quotes.
 117   for (char C : Name) {
 118     if (!isAcceptableChar(C))
 119       return false;
 120   }
 121
 122   return true;
 123 }
 124
 125 bool MCAsmInfo::shouldOmitSectionDirective(StringRef SectionName) const {
 126   // FIXME: Does .section .bss/.data/.text work everywhere??
 127   return SectionName == ".text" || SectionName == ".data" ||
 128         (SectionName == ".bss" && !usesELFSectionDirectiveForBSS());
 129 }