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 } 139