contrib/llvm/tools/lld/COFF/MinGW.cpp

   1 //===- MinGW.cpp ----------------------------------------------------------===//
   2 //
   3 //                             The LLVM Linker
   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 "MinGW.h"
  11 #include "SymbolTable.h"
  12 #include "lld/Common/ErrorHandler.h"
  13 #include "llvm/Object/COFF.h"
  14 #include "llvm/Support/Path.h"
  15 #include "llvm/Support/raw_ostream.h"
  16
  17 using namespace lld;
  18 using namespace lld::coff;
  19 using namespace llvm;
  20 using namespace llvm::COFF;
  21
  22 AutoExporter::AutoExporter() {
  23   if (Config->Machine == I386) {
  24     ExcludeSymbols = {
  25         "__NULL_IMPORT_DESCRIPTOR",
  26         "__pei386_runtime_relocator",
  27         "_do_pseudo_reloc",
  28         "_impure_ptr",
  29         "__impure_ptr",
  30         "__fmode",
  31         "_environ",
  32         "___dso_handle",
  33         // These are the MinGW names that differ from the standard
  34         // ones (lacking an extra underscore).
  35         "_DllMain@12",
  36         "_DllEntryPoint@12",
  37         "_DllMainCRTStartup@12",
  38     };
  39   } else {
  40     ExcludeSymbols = {
  41         "_NULL_IMPORT_DESCRIPTOR",
  42         "_pei386_runtime_relocator",
  43         "do_pseudo_reloc",
  44         "impure_ptr",
  45         "_impure_ptr",
  46         "_fmode",
  47         "environ",
  48         "__dso_handle",
  49         // These are the MinGW names that differ from the standard
  50         // ones (lacking an extra underscore).
  51         "DllMain",
  52         "DllEntryPoint",
  53         "DllMainCRTStartup",
  54     };
  55   }
  56
  57   ExcludeLibs = {
  58       "libgcc",
  59       "libgcc_s",
  60       "libstdc++",
  61       "libmingw32",
  62       "libmingwex",
  63       "libg2c",
  64       "libsupc++",
  65       "libobjc",
  66       "libgcj",
  67       "libclang_rt.builtins-aarch64",
  68       "libclang_rt.builtins-arm",
  69       "libclang_rt.builtins-i386",
  70       "libclang_rt.builtins-x86_64",
  71       "libc++",
  72       "libc++abi",
  73       "libunwind",
  74       "libmsvcrt",
  75       "libucrtbase",
  76   };
  77   ExcludeObjects = {
  78       "crt0.o",
  79       "crt1.o",
  80       "crt1u.o",
  81       "crt2.o",
  82       "crt2u.o",
  83       "dllcrt1.o",
  84       "dllcrt2.o",
  85       "gcrt0.o",
  86       "gcrt1.o",
  87       "gcrt2.o",
  88       "crtbegin.o",
  89       "crtend.o",
  90   };
  91 }
  92
  93 bool AutoExporter::shouldExport(Defined *Sym) const {
  94   if (!Sym || !Sym->isLive() || !Sym->getChunk())
  95     return false;
  96
  97   // Only allow the symbol kinds that make sense to export; in particular,
  98   // disallow import symbols.
  99   if (!isa<DefinedRegular>(Sym) && !isa<DefinedCommon>(Sym))
 100     return false;
 101   if (ExcludeSymbols.count(Sym->getName()))
 102     return false;
 103
 104   // Don't export anything that looks like an import symbol (which also can be
 105   // a manually defined data symbol with such a name).
 106   if (Sym->getName().startswith("__imp_"))
 107     return false;
 108
 109   // If a corresponding __imp_ symbol exists and is defined, don't export it.
 110   if (Symtab->find(("__imp_" + Sym->getName()).str()))
 111     return false;
 112
 113   // Check that file is non-null before dereferencing it, symbols not
 114   // originating in regular object files probably shouldn't be exported.
 115   if (!Sym->getFile())
 116     return false;
 117
 118   StringRef LibName = sys::path::filename(Sym->getFile()->ParentName);
 119
 120   // Drop the file extension.
 121   LibName = LibName.substr(0, LibName.rfind('.'));
 122   if (!LibName.empty())
 123     return !ExcludeLibs.count(LibName);
 124
 125   StringRef FileName = sys::path::filename(Sym->getFile()->getName());
 126   return !ExcludeObjects.count(FileName);
 127 }
 128
 129 void coff::writeDefFile(StringRef Name) {
 130   std::error_code EC;
 131   raw_fd_ostream OS(Name, EC, sys::fs::F_None);
 132   if (EC)
 133     fatal("cannot open " + Name + ": " + EC.message());
 134
 135   OS << "EXPORTS\n";
 136   for (Export &E : Config->Exports) {
 137     OS << "    " << E.ExportName << " "
 138        << "@" << E.Ordinal;
 139     if (auto *Def = dyn_cast_or_null<Defined>(E.Sym)) {
 140       if (Def && Def->getChunk() &&
 141           !(Def->getChunk()->getOutputCharacteristics() & IMAGE_SCN_MEM_EXECUTE))
 142         OS << " DATA";
 143     }
 144     OS << "\n";
 145   }
 146 }