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/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 namespace {
  24 enum DefaultOnOff { Default, Enable, Disable };
  25 }
  26 static cl::opt<DefaultOnOff> DwarfExtendedLoc(
  27     "dwarf-extended-loc", cl::Hidden,
  28     cl::desc("Disable emission of the extended flags in .loc directives."),
  29     cl::values(clEnumVal(Default, "Default for platform"),
  30                clEnumVal(Enable, "Enabled"), clEnumVal(Disable, "Disabled")),
  31     cl::init(Default));
  32
  33 namespace llvm {
  34 cl::opt<cl::boolOrDefault> UseLEB128Directives(
  35     "use-leb128-directives", cl::Hidden,
  36     cl::desc(
  37         "Disable the usage of LEB128 directives, and generate .byte instead."),
  38     cl::init(cl::BOU_UNSET));
  39 }
  40
  41 MCAsmInfo::MCAsmInfo() {
  42   SeparatorString = ";";
  43   CommentString = "#";
  44   LabelSuffix = ":";
  45   PrivateGlobalPrefix = "L";
  46   PrivateLabelPrefix = PrivateGlobalPrefix;
  47   LinkerPrivateGlobalPrefix = "";
  48   InlineAsmStart = "APP";
  49   InlineAsmEnd = "NO_APP";
  50   Code16Directive = ".code16";
  51   Code32Directive = ".code32";
  52   Code64Directive = ".code64";
  53   ZeroDirective = "\t.zero\t";
  54   AsciiDirective = "\t.ascii\t";
  55   AscizDirective = "\t.asciz\t";
  56   Data8bitsDirective = "\t.byte\t";
  57   Data16bitsDirective = "\t.short\t";
  58   Data32bitsDirective = "\t.long\t";
  59   Data64bitsDirective = "\t.quad\t";
  60   GlobalDirective = "\t.globl\t";
  61   WeakDirective = "\t.weak\t";
  62   if (DwarfExtendedLoc != Default)
  63     SupportsExtendedDwarfLocDirective = DwarfExtendedLoc == Enable;
  64   if (UseLEB128Directives != cl::BOU_UNSET)
  65     HasLEB128Directives = UseLEB128Directives == cl::BOU_TRUE;
  66
  67   // FIXME: Clang's logic should be synced with the logic used to initialize
  68   //        this member and the two implementations should be merged.
  69   // For reference:
  70   // - Solaris always enables the integrated assembler by default
  71   //   - SparcELFMCAsmInfo and X86ELFMCAsmInfo are handling this case
  72   // - Windows always enables the integrated assembler by default
  73   //   - MCAsmInfoCOFF is handling this case, should it be MCAsmInfoMicrosoft?
  74   // - MachO targets always enables the integrated assembler by default
  75   //   - MCAsmInfoDarwin is handling this case
  76   // - Generic_GCC toolchains enable the integrated assembler on a per
  77   //   architecture basis.
  78   //   - The target subclasses for AArch64, ARM, and X86 handle these cases
  79   UseIntegratedAssembler = true;
  80   ParseInlineAsmUsingAsmParser = false;
  81   PreserveAsmComments = true;
  82 }
  83
  84 MCAsmInfo::~MCAsmInfo() = default;
  85
  86 void MCAsmInfo::addInitialFrameState(const MCCFIInstruction &Inst) {
  87   InitialFrameState.push_back(Inst);
  88 }
  89
  90 bool MCAsmInfo::isSectionAtomizableBySymbols(const MCSection &Section) const {
  91   return false;
  92 }
  93
  94 const MCExpr *
  95 MCAsmInfo::getExprForPersonalitySymbol(const MCSymbol *Sym,
  96                                        unsigned Encoding,
  97                                        MCStreamer &Streamer) const {
  98   return getExprForFDESymbol(Sym, Encoding, Streamer);
  99 }
 100
 101 const MCExpr *
 102 MCAsmInfo::getExprForFDESymbol(const MCSymbol *Sym,
 103                                unsigned Encoding,
 104                                MCStreamer &Streamer) const {
 105   if (!(Encoding & dwarf::DW_EH_PE_pcrel))
 106     return MCSymbolRefExpr::create(Sym, Streamer.getContext());
 107
 108   MCContext &Context = Streamer.getContext();
 109   const MCExpr *Res = MCSymbolRefExpr::create(Sym, Context);
 110   MCSymbol *PCSym = Context.createTempSymbol();
 111   Streamer.emitLabel(PCSym);
 112   const MCExpr *PC = MCSymbolRefExpr::create(PCSym, Context);
 113   return MCBinaryExpr::createSub(Res, PC, Context);
 114 }
 115
 116 bool MCAsmInfo::isAcceptableChar(char C) const {
 117   return isAlnum(C) || C == '_' || C == '$' || C == '.' || C == '@';
 118 }
 119
 120 bool MCAsmInfo::isValidUnquotedName(StringRef Name) const {
 121   if (Name.empty())
 122     return false;
 123
 124   // If any of the characters in the string is an unacceptable character, force
 125   // quotes.
 126   for (char C : Name) {
 127     if (!isAcceptableChar(C))
 128       return false;
 129   }
 130
 131   return true;
 132 }
 133
 134 bool MCAsmInfo::shouldOmitSectionDirective(StringRef SectionName) const {
 135   // FIXME: Does .section .bss/.data/.text work everywhere??
 136   return SectionName == ".text" || SectionName == ".data" ||
 137         (SectionName == ".bss" && !usesELFSectionDirectiveForBSS());
 138 }