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