1 //===- lib/MC/MCSectionELF.cpp - ELF Code Section Representation ----------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #include "llvm/MC/MCSectionELF.h" 11 #include "llvm/MC/MCAsmInfo.h" 12 #include "llvm/MC/MCContext.h" 13 #include "llvm/MC/MCSymbol.h" 14 #include "llvm/Support/ELF.h" 15 #include "llvm/Support/raw_ostream.h" 16 17 using namespace llvm; 18 19 MCSectionELF::~MCSectionELF() {} // anchor. 20 21 // ShouldOmitSectionDirective - Decides whether a '.section' directive 22 // should be printed before the section name 23 bool MCSectionELF::ShouldOmitSectionDirective(StringRef Name, 24 const MCAsmInfo &MAI) const { 25 26 // FIXME: Does .section .bss/.data/.text work everywhere?? 27 if (Name == ".text" || Name == ".data" || 28 (Name == ".bss" && !MAI.usesELFSectionDirectiveForBSS())) 29 return true; 30 31 return false; 32 } 33 34 void MCSectionELF::PrintSwitchToSection(const MCAsmInfo &MAI, 35 raw_ostream &OS) const { 36 37 if (ShouldOmitSectionDirective(SectionName, MAI)) { 38 OS << '\t' << getSectionName() << '\n'; 39 return; 40 } 41 42 StringRef name = getSectionName(); 43 if (name.find_first_not_of("0123456789_." 44 "abcdefghijklmnopqrstuvwxyz" 45 "ABCDEFGHIJKLMNOPQRSTUVWXYZ") == name.npos) { 46 OS << "\t.section\t" << name; 47 } else { 48 OS << "\t.section\t\""; 49 for (const char *b = name.begin(), *e = name.end(); b < e; ++b) { 50 if (*b == '"') // Unquoted " 51 OS << "\\\""; 52 else if (*b != '\\') // Neither " or backslash 53 OS << *b; 54 else if (b + 1 == e) // Trailing backslash 55 OS << "\\\\"; 56 else { 57 OS << b[0] << b[1]; // Quoted character 58 ++b; 59 } 60 } 61 OS << '"'; 62 } 63 64 // Handle the weird solaris syntax if desired. 65 if (MAI.usesSunStyleELFSectionSwitchSyntax() && 66 !(Flags & ELF::SHF_MERGE)) { 67 if (Flags & ELF::SHF_ALLOC) 68 OS << ",#alloc"; 69 if (Flags & ELF::SHF_EXECINSTR) 70 OS << ",#execinstr"; 71 if (Flags & ELF::SHF_WRITE) 72 OS << ",#write"; 73 if (Flags & ELF::SHF_TLS) 74 OS << ",#tls"; 75 OS << '\n'; 76 return; 77 } 78 79 OS << ",\""; 80 if (Flags & ELF::SHF_ALLOC) 81 OS << 'a'; 82 if (Flags & ELF::SHF_EXECINSTR) 83 OS << 'x'; 84 if (Flags & ELF::SHF_GROUP) 85 OS << 'G'; 86 if (Flags & ELF::SHF_WRITE) 87 OS << 'w'; 88 if (Flags & ELF::SHF_MERGE) 89 OS << 'M'; 90 if (Flags & ELF::SHF_STRINGS) 91 OS << 'S'; 92 if (Flags & ELF::SHF_TLS) 93 OS << 'T'; 94 95 // If there are target-specific flags, print them. 96 if (Flags & ELF::XCORE_SHF_CP_SECTION) 97 OS << 'c'; 98 if (Flags & ELF::XCORE_SHF_DP_SECTION) 99 OS << 'd'; 100 101 OS << '"'; 102 103 OS << ','; 104 105 // If comment string is '@', e.g. as on ARM - use '%' instead 106 if (MAI.getCommentString()[0] == '@') 107 OS << '%'; 108 else 109 OS << '@'; 110 111 if (Type == ELF::SHT_INIT_ARRAY) 112 OS << "init_array"; 113 else if (Type == ELF::SHT_FINI_ARRAY) 114 OS << "fini_array"; 115 else if (Type == ELF::SHT_PREINIT_ARRAY) 116 OS << "preinit_array"; 117 else if (Type == ELF::SHT_NOBITS) 118 OS << "nobits"; 119 else if (Type == ELF::SHT_NOTE) 120 OS << "note"; 121 else if (Type == ELF::SHT_PROGBITS) 122 OS << "progbits"; 123 124 if (EntrySize) { 125 assert(Flags & ELF::SHF_MERGE); 126 OS << "," << EntrySize; 127 } 128 129 if (Flags & ELF::SHF_GROUP) 130 OS << "," << Group->getName() << ",comdat"; 131 OS << '\n'; 132 } 133 134 bool MCSectionELF::UseCodeAlign() const { 135 return getFlags() & ELF::SHF_EXECINSTR; 136 } 137 138 bool MCSectionELF::isVirtualSection() const { 139 return getType() == ELF::SHT_NOBITS; 140 } 141 142 unsigned MCSectionELF::DetermineEntrySize(SectionKind Kind) { 143 if (Kind.isMergeable1ByteCString()) return 1; 144 if (Kind.isMergeable2ByteCString()) return 2; 145 if (Kind.isMergeable4ByteCString()) return 4; 146 if (Kind.isMergeableConst4()) return 4; 147 if (Kind.isMergeableConst8()) return 8; 148 if (Kind.isMergeableConst16()) return 16; 149 return 0; 150 } 151