1 //===- lib/MC/MCSectionELF.cpp - ELF Code Section Representation ----------===// 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 #include "llvm/MC/MCSectionELF.h" 10 #include "llvm/BinaryFormat/ELF.h" 11 #include "llvm/MC/MCAsmInfo.h" 12 #include "llvm/MC/MCExpr.h" 13 #include "llvm/Support/ErrorHandling.h" 14 #include "llvm/Support/raw_ostream.h" 15 #include "llvm/TargetParser/Triple.h" 16 #include <cassert> 17 18 using namespace llvm; 19 20 // Decides whether a '.section' directive 21 // should be printed before the section name. 22 bool MCSectionELF::shouldOmitSectionDirective(StringRef Name, 23 const MCAsmInfo &MAI) const { 24 if (isUnique()) 25 return false; 26 27 return MAI.shouldOmitSectionDirective(Name); 28 } 29 30 static void printName(raw_ostream &OS, StringRef Name) { 31 if (Name.find_first_not_of("0123456789_." 32 "abcdefghijklmnopqrstuvwxyz" 33 "ABCDEFGHIJKLMNOPQRSTUVWXYZ") == Name.npos) { 34 OS << Name; 35 return; 36 } 37 OS << '"'; 38 for (const char *B = Name.begin(), *E = Name.end(); B < E; ++B) { 39 if (*B == '"') // Unquoted " 40 OS << "\\\""; 41 else if (*B != '\\') // Neither " or backslash 42 OS << *B; 43 else if (B + 1 == E) // Trailing backslash 44 OS << "\\\\"; 45 else { 46 OS << B[0] << B[1]; // Quoted character 47 ++B; 48 } 49 } 50 OS << '"'; 51 } 52 53 void MCSectionELF::printSwitchToSection(const MCAsmInfo &MAI, const Triple &T, 54 raw_ostream &OS, 55 uint32_t Subsection) const { 56 if (shouldOmitSectionDirective(getName(), MAI)) { 57 OS << '\t' << getName(); 58 if (Subsection) 59 OS << '\t' << Subsection; 60 OS << '\n'; 61 return; 62 } 63 64 OS << "\t.section\t"; 65 printName(OS, getName()); 66 67 // Handle the weird solaris syntax if desired. 68 if (MAI.usesSunStyleELFSectionSwitchSyntax() && 69 !(Flags & ELF::SHF_MERGE)) { 70 if (Flags & ELF::SHF_ALLOC) 71 OS << ",#alloc"; 72 if (Flags & ELF::SHF_EXECINSTR) 73 OS << ",#execinstr"; 74 if (Flags & ELF::SHF_WRITE) 75 OS << ",#write"; 76 if (Flags & ELF::SHF_EXCLUDE) 77 OS << ",#exclude"; 78 if (Flags & ELF::SHF_TLS) 79 OS << ",#tls"; 80 OS << '\n'; 81 return; 82 } 83 84 OS << ",\""; 85 if (Flags & ELF::SHF_ALLOC) 86 OS << 'a'; 87 if (Flags & ELF::SHF_EXCLUDE) 88 OS << 'e'; 89 if (Flags & ELF::SHF_EXECINSTR) 90 OS << 'x'; 91 if (Flags & ELF::SHF_WRITE) 92 OS << 'w'; 93 if (Flags & ELF::SHF_MERGE) 94 OS << 'M'; 95 if (Flags & ELF::SHF_STRINGS) 96 OS << 'S'; 97 if (Flags & ELF::SHF_TLS) 98 OS << 'T'; 99 if (Flags & ELF::SHF_LINK_ORDER) 100 OS << 'o'; 101 if (Flags & ELF::SHF_GROUP) 102 OS << 'G'; 103 if (Flags & ELF::SHF_GNU_RETAIN) 104 OS << 'R'; 105 106 // If there are os-specific flags, print them. 107 if (T.isOSSolaris()) 108 if (Flags & ELF::SHF_SUNW_NODISCARD) 109 OS << 'R'; 110 111 // If there are target-specific flags, print them. 112 Triple::ArchType Arch = T.getArch(); 113 if (Arch == Triple::xcore) { 114 if (Flags & ELF::XCORE_SHF_CP_SECTION) 115 OS << 'c'; 116 if (Flags & ELF::XCORE_SHF_DP_SECTION) 117 OS << 'd'; 118 } else if (T.isARM() || T.isThumb()) { 119 if (Flags & ELF::SHF_ARM_PURECODE) 120 OS << 'y'; 121 } else if (Arch == Triple::hexagon) { 122 if (Flags & ELF::SHF_HEX_GPREL) 123 OS << 's'; 124 } else if (Arch == Triple::x86_64) { 125 if (Flags & ELF::SHF_X86_64_LARGE) 126 OS << 'l'; 127 } 128 129 OS << '"'; 130 131 OS << ','; 132 133 // If comment string is '@', e.g. as on ARM - use '%' instead 134 if (MAI.getCommentString()[0] == '@') 135 OS << '%'; 136 else 137 OS << '@'; 138 139 if (Type == ELF::SHT_INIT_ARRAY) 140 OS << "init_array"; 141 else if (Type == ELF::SHT_FINI_ARRAY) 142 OS << "fini_array"; 143 else if (Type == ELF::SHT_PREINIT_ARRAY) 144 OS << "preinit_array"; 145 else if (Type == ELF::SHT_NOBITS) 146 OS << "nobits"; 147 else if (Type == ELF::SHT_NOTE) 148 OS << "note"; 149 else if (Type == ELF::SHT_PROGBITS) 150 OS << "progbits"; 151 else if (Type == ELF::SHT_X86_64_UNWIND) 152 OS << "unwind"; 153 else if (Type == ELF::SHT_MIPS_DWARF) 154 // Print hex value of the flag while we do not have 155 // any standard symbolic representation of the flag. 156 OS << "0x7000001e"; 157 else if (Type == ELF::SHT_LLVM_ODRTAB) 158 OS << "llvm_odrtab"; 159 else if (Type == ELF::SHT_LLVM_LINKER_OPTIONS) 160 OS << "llvm_linker_options"; 161 else if (Type == ELF::SHT_LLVM_CALL_GRAPH_PROFILE) 162 OS << "llvm_call_graph_profile"; 163 else if (Type == ELF::SHT_LLVM_DEPENDENT_LIBRARIES) 164 OS << "llvm_dependent_libraries"; 165 else if (Type == ELF::SHT_LLVM_SYMPART) 166 OS << "llvm_sympart"; 167 else if (Type == ELF::SHT_LLVM_BB_ADDR_MAP) 168 OS << "llvm_bb_addr_map"; 169 else if (Type == ELF::SHT_LLVM_BB_ADDR_MAP_V0) 170 OS << "llvm_bb_addr_map_v0"; 171 else if (Type == ELF::SHT_LLVM_OFFLOADING) 172 OS << "llvm_offloading"; 173 else if (Type == ELF::SHT_LLVM_LTO) 174 OS << "llvm_lto"; 175 else 176 OS << "0x" << Twine::utohexstr(Type); 177 178 if (EntrySize) { 179 assert(Flags & ELF::SHF_MERGE); 180 OS << "," << EntrySize; 181 } 182 183 if (Flags & ELF::SHF_LINK_ORDER) { 184 OS << ","; 185 if (LinkedToSym) 186 printName(OS, LinkedToSym->getName()); 187 else 188 OS << '0'; 189 } 190 191 if (Flags & ELF::SHF_GROUP) { 192 OS << ","; 193 printName(OS, Group.getPointer()->getName()); 194 if (isComdat()) 195 OS << ",comdat"; 196 } 197 198 if (isUnique()) 199 OS << ",unique," << UniqueID; 200 201 OS << '\n'; 202 203 if (Subsection) { 204 OS << "\t.subsection\t" << Subsection; 205 OS << '\n'; 206 } 207 } 208 209 bool MCSectionELF::useCodeAlign() const { 210 return getFlags() & ELF::SHF_EXECINSTR; 211 } 212 213 StringRef MCSectionELF::getVirtualSectionKind() const { return "SHT_NOBITS"; } 214