1 //===- MinGW.cpp ----------------------------------------------------------===// 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 "MinGW.h" 10 #include "SymbolTable.h" 11 #include "lld/Common/ErrorHandler.h" 12 #include "llvm/Object/COFF.h" 13 #include "llvm/Support/Path.h" 14 #include "llvm/Support/raw_ostream.h" 15 16 using namespace llvm; 17 using namespace llvm::COFF; 18 using namespace lld; 19 using namespace lld::coff; 20 21 AutoExporter::AutoExporter() { 22 excludeLibs = { 23 "libgcc", 24 "libgcc_s", 25 "libstdc++", 26 "libmingw32", 27 "libmingwex", 28 "libg2c", 29 "libsupc++", 30 "libobjc", 31 "libgcj", 32 "libclang_rt.builtins", 33 "libclang_rt.builtins-aarch64", 34 "libclang_rt.builtins-arm", 35 "libclang_rt.builtins-i386", 36 "libclang_rt.builtins-x86_64", 37 "libclang_rt.profile", 38 "libclang_rt.profile-aarch64", 39 "libclang_rt.profile-arm", 40 "libclang_rt.profile-i386", 41 "libclang_rt.profile-x86_64", 42 "libc++", 43 "libc++abi", 44 "libunwind", 45 "libmsvcrt", 46 "libucrtbase", 47 }; 48 49 excludeObjects = { 50 "crt0.o", "crt1.o", "crt1u.o", "crt2.o", "crt2u.o", "dllcrt1.o", 51 "dllcrt2.o", "gcrt0.o", "gcrt1.o", "gcrt2.o", "crtbegin.o", "crtend.o", 52 }; 53 54 excludeSymbolPrefixes = { 55 // Import symbols 56 "__imp_", 57 "__IMPORT_DESCRIPTOR_", 58 // Extra import symbols from GNU import libraries 59 "__nm_", 60 // C++ symbols 61 "__rtti_", 62 "__builtin_", 63 // Artificial symbols such as .refptr 64 ".", 65 // profile generate symbols 66 "__profc_", 67 "__profd_", 68 "__profvp_", 69 }; 70 71 excludeSymbolSuffixes = { 72 "_iname", 73 "_NULL_THUNK_DATA", 74 }; 75 76 if (config->machine == I386) { 77 excludeSymbols = { 78 "__NULL_IMPORT_DESCRIPTOR", 79 "__pei386_runtime_relocator", 80 "_do_pseudo_reloc", 81 "_impure_ptr", 82 "__impure_ptr", 83 "__fmode", 84 "_environ", 85 "___dso_handle", 86 // These are the MinGW names that differ from the standard 87 // ones (lacking an extra underscore). 88 "_DllMain@12", 89 "_DllEntryPoint@12", 90 "_DllMainCRTStartup@12", 91 }; 92 excludeSymbolPrefixes.insert("__head_"); 93 } else { 94 excludeSymbols = { 95 "__NULL_IMPORT_DESCRIPTOR", 96 "_pei386_runtime_relocator", 97 "do_pseudo_reloc", 98 "impure_ptr", 99 "_impure_ptr", 100 "_fmode", 101 "environ", 102 "__dso_handle", 103 // These are the MinGW names that differ from the standard 104 // ones (lacking an extra underscore). 105 "DllMain", 106 "DllEntryPoint", 107 "DllMainCRTStartup", 108 }; 109 excludeSymbolPrefixes.insert("_head_"); 110 } 111 } 112 113 void AutoExporter::addWholeArchive(StringRef path) { 114 StringRef libName = sys::path::filename(path); 115 // Drop the file extension, to match the processing below. 116 libName = libName.substr(0, libName.rfind('.')); 117 excludeLibs.erase(libName); 118 } 119 120 bool AutoExporter::shouldExport(Defined *sym) const { 121 if (!sym || !sym->isLive() || !sym->getChunk()) 122 return false; 123 124 // Only allow the symbol kinds that make sense to export; in particular, 125 // disallow import symbols. 126 if (!isa<DefinedRegular>(sym) && !isa<DefinedCommon>(sym)) 127 return false; 128 if (excludeSymbols.count(sym->getName())) 129 return false; 130 131 for (StringRef prefix : excludeSymbolPrefixes.keys()) 132 if (sym->getName().startswith(prefix)) 133 return false; 134 for (StringRef suffix : excludeSymbolSuffixes.keys()) 135 if (sym->getName().endswith(suffix)) 136 return false; 137 138 // If a corresponding __imp_ symbol exists and is defined, don't export it. 139 if (symtab->find(("__imp_" + sym->getName()).str())) 140 return false; 141 142 // Check that file is non-null before dereferencing it, symbols not 143 // originating in regular object files probably shouldn't be exported. 144 if (!sym->getFile()) 145 return false; 146 147 StringRef libName = sys::path::filename(sym->getFile()->parentName); 148 149 // Drop the file extension. 150 libName = libName.substr(0, libName.rfind('.')); 151 if (!libName.empty()) 152 return !excludeLibs.count(libName); 153 154 StringRef fileName = sys::path::filename(sym->getFile()->getName()); 155 return !excludeObjects.count(fileName); 156 } 157 158 void lld::coff::writeDefFile(StringRef name) { 159 std::error_code ec; 160 raw_fd_ostream os(name, ec, sys::fs::OF_None); 161 if (ec) 162 fatal("cannot open " + name + ": " + ec.message()); 163 164 os << "EXPORTS\n"; 165 for (Export &e : config->exports) { 166 os << " " << e.exportName << " " 167 << "@" << e.ordinal; 168 if (auto *def = dyn_cast_or_null<Defined>(e.sym)) { 169 if (def && def->getChunk() && 170 !(def->getChunk()->getOutputCharacteristics() & IMAGE_SCN_MEM_EXECUTE)) 171 os << " DATA"; 172 } 173 os << "\n"; 174 } 175 } 176