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/ADT/Twine.h" 11 #include "llvm/BinaryFormat/ELF.h" 12 #include "llvm/MC/MCAsmInfo.h" 13 #include "llvm/MC/MCExpr.h" 14 #include "llvm/Support/ErrorHandling.h" 15 #include "llvm/Support/raw_ostream.h" 16 #include "llvm/TargetParser/Triple.h" 17 #include <cassert> 18 19 using namespace llvm; 20 21 // 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 if (isUnique()) 26 return false; 27 28 return MAI.shouldOmitSectionDirective(Name); 29 } 30 31 static void printName(raw_ostream &OS, StringRef Name) { 32 if (Name.find_first_not_of("0123456789_." 33 "abcdefghijklmnopqrstuvwxyz" 34 "ABCDEFGHIJKLMNOPQRSTUVWXYZ") == Name.npos) { 35 OS << Name; 36 return; 37 } 38 OS << '"'; 39 for (const char *B = Name.begin(), *E = Name.end(); B < E; ++B) { 40 if (*B == '"') // Unquoted " 41 OS << "\\\""; 42 else if (*B != '\\') // Neither " or backslash 43 OS << *B; 44 else if (B + 1 == E) // Trailing backslash 45 OS << "\\\\"; 46 else { 47 OS << B[0] << B[1]; // Quoted character 48 ++B; 49 } 50 } 51 OS << '"'; 52 } 53 54 void MCSectionELF::printSwitchToSection(const MCAsmInfo &MAI, const Triple &T, 55 raw_ostream &OS, 56 uint32_t Subsection) const { 57 if (shouldOmitSectionDirective(getName(), MAI)) { 58 OS << '\t' << getName(); 59 if (Subsection) 60 OS << '\t' << Subsection; 61 OS << '\n'; 62 return; 63 } 64 65 OS << "\t.section\t"; 66 printName(OS, getName()); 67 68 // Handle the weird solaris syntax if desired. 69 if (MAI.usesSunStyleELFSectionSwitchSyntax() && 70 !(Flags & ELF::SHF_MERGE)) { 71 if (Flags & ELF::SHF_ALLOC) 72 OS << ",#alloc"; 73 if (Flags & ELF::SHF_EXECINSTR) 74 OS << ",#execinstr"; 75 if (Flags & ELF::SHF_WRITE) 76 OS << ",#write"; 77 if (Flags & ELF::SHF_EXCLUDE) 78 OS << ",#exclude"; 79 if (Flags & ELF::SHF_TLS) 80 OS << ",#tls"; 81 OS << '\n'; 82 return; 83 } 84 85 OS << ",\""; 86 if (Flags & ELF::SHF_ALLOC) 87 OS << 'a'; 88 if (Flags & ELF::SHF_EXCLUDE) 89 OS << 'e'; 90 if (Flags & ELF::SHF_EXECINSTR) 91 OS << 'x'; 92 if (Flags & ELF::SHF_WRITE) 93 OS << 'w'; 94 if (Flags & ELF::SHF_MERGE) 95 OS << 'M'; 96 if (Flags & ELF::SHF_STRINGS) 97 OS << 'S'; 98 if (Flags & ELF::SHF_TLS) 99 OS << 'T'; 100 if (Flags & ELF::SHF_LINK_ORDER) 101 OS << 'o'; 102 if (Flags & ELF::SHF_GROUP) 103 OS << 'G'; 104 if (Flags & ELF::SHF_GNU_RETAIN) 105 OS << 'R'; 106 107 // If there are os-specific flags, print them. 108 if (T.isOSSolaris()) 109 if (Flags & ELF::SHF_SUNW_NODISCARD) 110 OS << 'R'; 111 112 // If there are target-specific flags, print them. 113 Triple::ArchType Arch = T.getArch(); 114 if (Arch == Triple::xcore) { 115 if (Flags & ELF::XCORE_SHF_CP_SECTION) 116 OS << 'c'; 117 if (Flags & ELF::XCORE_SHF_DP_SECTION) 118 OS << 'd'; 119 } else if (T.isARM() || T.isThumb()) { 120 if (Flags & ELF::SHF_ARM_PURECODE) 121 OS << 'y'; 122 } else if (T.isAArch64()) { 123 if (Flags & ELF::SHF_AARCH64_PURECODE) 124 OS << 'y'; 125 } else if (Arch == Triple::hexagon) { 126 if (Flags & ELF::SHF_HEX_GPREL) 127 OS << 's'; 128 } else if (Arch == Triple::x86_64) { 129 if (Flags & ELF::SHF_X86_64_LARGE) 130 OS << 'l'; 131 } 132 133 OS << '"'; 134 135 OS << ','; 136 137 // If comment string is '@', e.g. as on ARM - use '%' instead 138 if (MAI.getCommentString()[0] == '@') 139 OS << '%'; 140 else 141 OS << '@'; 142 143 if (Type == ELF::SHT_INIT_ARRAY) 144 OS << "init_array"; 145 else if (Type == ELF::SHT_FINI_ARRAY) 146 OS << "fini_array"; 147 else if (Type == ELF::SHT_PREINIT_ARRAY) 148 OS << "preinit_array"; 149 else if (Type == ELF::SHT_NOBITS) 150 OS << "nobits"; 151 else if (Type == ELF::SHT_NOTE) 152 OS << "note"; 153 else if (Type == ELF::SHT_PROGBITS) 154 OS << "progbits"; 155 else if (Type == ELF::SHT_X86_64_UNWIND) 156 OS << "unwind"; 157 else if (Type == ELF::SHT_MIPS_DWARF) 158 // Print hex value of the flag while we do not have 159 // any standard symbolic representation of the flag. 160 OS << "0x7000001e"; 161 else if (Type == ELF::SHT_LLVM_ODRTAB) 162 OS << "llvm_odrtab"; 163 else if (Type == ELF::SHT_LLVM_LINKER_OPTIONS) 164 OS << "llvm_linker_options"; 165 else if (Type == ELF::SHT_LLVM_CALL_GRAPH_PROFILE) 166 OS << "llvm_call_graph_profile"; 167 else if (Type == ELF::SHT_LLVM_DEPENDENT_LIBRARIES) 168 OS << "llvm_dependent_libraries"; 169 else if (Type == ELF::SHT_LLVM_SYMPART) 170 OS << "llvm_sympart"; 171 else if (Type == ELF::SHT_LLVM_BB_ADDR_MAP) 172 OS << "llvm_bb_addr_map"; 173 else if (Type == ELF::SHT_LLVM_OFFLOADING) 174 OS << "llvm_offloading"; 175 else if (Type == ELF::SHT_LLVM_LTO) 176 OS << "llvm_lto"; 177 else if (Type == ELF::SHT_LLVM_JT_SIZES) 178 OS << "llvm_jt_sizes"; 179 else 180 OS << "0x" << Twine::utohexstr(Type); 181 182 if (EntrySize) { 183 assert(Flags & ELF::SHF_MERGE); 184 OS << "," << EntrySize; 185 } 186 187 if (Flags & ELF::SHF_LINK_ORDER) { 188 OS << ","; 189 if (LinkedToSym) 190 printName(OS, LinkedToSym->getName()); 191 else 192 OS << '0'; 193 } 194 195 if (Flags & ELF::SHF_GROUP) { 196 OS << ","; 197 printName(OS, Group.getPointer()->getName()); 198 if (isComdat()) 199 OS << ",comdat"; 200 } 201 202 if (isUnique()) 203 OS << ",unique," << UniqueID; 204 205 OS << '\n'; 206 207 if (Subsection) { 208 OS << "\t.subsection\t" << Subsection; 209 OS << '\n'; 210 } 211 } 212 213 bool MCSectionELF::useCodeAlign() const { 214 return getFlags() & ELF::SHF_EXECINSTR; 215 } 216 217 StringRef MCSectionELF::getVirtualSectionKind() const { return "SHT_NOBITS"; } 218