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 68 // FIXME: Clang's logic should be synced with the logic used to initialize 69 // this member and the two implementations should be merged. 70 // For reference: 71 // - Solaris always enables the integrated assembler by default 72 // - SparcELFMCAsmInfo and X86ELFMCAsmInfo are handling this case 73 // - Windows always enables the integrated assembler by default 74 // - MCAsmInfoCOFF is handling this case, should it be MCAsmInfoMicrosoft? 75 // - MachO targets always enables the integrated assembler by default 76 // - MCAsmInfoDarwin is handling this case 77 // - Generic_GCC toolchains enable the integrated assembler on a per 78 // architecture basis. 79 // - The target subclasses for AArch64, ARM, and X86 handle these cases 80 UseIntegratedAssembler = true; 81 ParseInlineAsmUsingAsmParser = false; 82 PreserveAsmComments = true; 83 } 84 85 MCAsmInfo::~MCAsmInfo() = default; 86 87 void MCAsmInfo::addInitialFrameState(const MCCFIInstruction &Inst) { 88 InitialFrameState.push_back(Inst); 89 } 90 91 bool MCAsmInfo::isSectionAtomizableBySymbols(const MCSection &Section) const { 92 return false; 93 } 94 95 const MCExpr * 96 MCAsmInfo::getExprForPersonalitySymbol(const MCSymbol *Sym, 97 unsigned Encoding, 98 MCStreamer &Streamer) const { 99 return getExprForFDESymbol(Sym, Encoding, Streamer); 100 } 101 102 const MCExpr * 103 MCAsmInfo::getExprForFDESymbol(const MCSymbol *Sym, 104 unsigned Encoding, 105 MCStreamer &Streamer) const { 106 if (!(Encoding & dwarf::DW_EH_PE_pcrel)) 107 return MCSymbolRefExpr::create(Sym, Streamer.getContext()); 108 109 MCContext &Context = Streamer.getContext(); 110 const MCExpr *Res = MCSymbolRefExpr::create(Sym, Context); 111 MCSymbol *PCSym = Context.createTempSymbol(); 112 Streamer.emitLabel(PCSym); 113 const MCExpr *PC = MCSymbolRefExpr::create(PCSym, Context); 114 return MCBinaryExpr::createSub(Res, PC, Context); 115 } 116 117 bool MCAsmInfo::isAcceptableChar(char C) const { 118 if (C == '@') 119 return doesAllowAtInName(); 120 121 return isAlnum(C) || C == '_' || C == '$' || C == '.'; 122 } 123 124 bool MCAsmInfo::isValidUnquotedName(StringRef Name) const { 125 if (Name.empty()) 126 return false; 127 128 // If any of the characters in the string is an unacceptable character, force 129 // quotes. 130 for (char C : Name) { 131 if (!isAcceptableChar(C)) 132 return false; 133 } 134 135 return true; 136 } 137 138 bool MCAsmInfo::shouldOmitSectionDirective(StringRef SectionName) const { 139 // FIXME: Does .section .bss/.data/.text work everywhere?? 140 return SectionName == ".text" || SectionName == ".data" || 141 (SectionName == ".bss" && !usesELFSectionDirectiveForBSS()); 142 } 143