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 = true; 68 PreserveAsmComments = true; 69 } 70 71 MCAsmInfo::~MCAsmInfo() = default; 72 73 void MCAsmInfo::addInitialFrameState(const MCCFIInstruction &Inst) { 74 InitialFrameState.push_back(Inst); 75 } 76 77 bool MCAsmInfo::isSectionAtomizableBySymbols(const MCSection &Section) const { 78 return false; 79 } 80 81 const MCExpr * 82 MCAsmInfo::getExprForPersonalitySymbol(const MCSymbol *Sym, 83 unsigned Encoding, 84 MCStreamer &Streamer) const { 85 return getExprForFDESymbol(Sym, Encoding, Streamer); 86 } 87 88 const MCExpr * 89 MCAsmInfo::getExprForFDESymbol(const MCSymbol *Sym, 90 unsigned Encoding, 91 MCStreamer &Streamer) const { 92 if (!(Encoding & dwarf::DW_EH_PE_pcrel)) 93 return MCSymbolRefExpr::create(Sym, Streamer.getContext()); 94 95 MCContext &Context = Streamer.getContext(); 96 const MCExpr *Res = MCSymbolRefExpr::create(Sym, Context); 97 MCSymbol *PCSym = Context.createTempSymbol(); 98 Streamer.emitLabel(PCSym); 99 const MCExpr *PC = MCSymbolRefExpr::create(PCSym, Context); 100 return MCBinaryExpr::createSub(Res, PC, Context); 101 } 102 103 bool MCAsmInfo::isAcceptableChar(char C) const { 104 return (C >= 'a' && C <= 'z') || (C >= 'A' && C <= 'Z') || 105 (C >= '0' && C <= '9') || C == '_' || C == '$' || C == '.' || C == '@'; 106 } 107 108 bool MCAsmInfo::isValidUnquotedName(StringRef Name) const { 109 if (Name.empty()) 110 return false; 111 112 // If any of the characters in the string is an unacceptable character, force 113 // quotes. 114 for (char C : Name) { 115 if (!isAcceptableChar(C)) 116 return false; 117 } 118 119 return true; 120 } 121 122 bool MCAsmInfo::shouldOmitSectionDirective(StringRef SectionName) const { 123 // FIXME: Does .section .bss/.data/.text work everywhere?? 124 return SectionName == ".text" || SectionName == ".data" || 125 (SectionName == ".bss" && !usesELFSectionDirectiveForBSS()); 126 } 127