lib/Object/COFFModuleDefinition.cpp

   1 //===--- COFFModuleDefinition.cpp - Simple DEF parser ---------------------===//
   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 // Windows-specific.
  11 // A parser for the module-definition file (.def file).
  12 //
  13 // The format of module-definition files are described in this document:
  14 // https://msdn.microsoft.com/en-us/library/28d6s79h.aspx
  15 //
  16 //===----------------------------------------------------------------------===//
  17
  18 #include "llvm/Object/COFFModuleDefinition.h"
  19 #include "llvm/ADT/StringRef.h"
  20 #include "llvm/ADT/StringSwitch.h"
  21 #include "llvm/Object/COFF.h"
  22 #include "llvm/Object/COFFImportFile.h"
  23 #include "llvm/Object/Error.h"
  24 #include "llvm/Support/Error.h"
  25 #include "llvm/Support/Path.h"
  26 #include "llvm/Support/raw_ostream.h"
  27
  28 using namespace llvm::COFF;
  29 using namespace llvm;
  30
  31 namespace llvm {
  32 namespace object {
  33
  34 enum Kind {
  35   Unknown,
  36   Eof,
  37   Identifier,
  38   Comma,
  39   Equal,
  40   EqualEqual,
  41   KwBase,
  42   KwConstant,
  43   KwData,
  44   KwExports,
  45   KwHeapsize,
  46   KwLibrary,
  47   KwName,
  48   KwNoname,
  49   KwPrivate,
  50   KwStacksize,
  51   KwVersion,
  52 };
  53
  54 struct Token {
  55   explicit Token(Kind T = Unknown, StringRef S = "") : K(T), Value(S) {}
  56   Kind K;
  57   StringRef Value;
  58 };
  59
  60 static bool isDecorated(StringRef Sym, bool MingwDef) {
  61   // In def files, the symbols can either be listed decorated or undecorated.
  62   //
  63   // - For cdecl symbols, only the undecorated form is allowed.
  64   // - For fastcall and vectorcall symbols, both fully decorated or
  65   //   undecorated forms can be present.
  66   // - For stdcall symbols in non-MinGW environments, the decorated form is
  67   //   fully decorated with leading underscore and trailing stack argument
  68   //   size - like "_Func@0".
  69   // - In MinGW def files, a decorated stdcall symbol does not include the
  70   //   leading underscore though, like "Func@0".
  71
  72   // This function controls whether a leading underscore should be added to
  73   // the given symbol name or not. For MinGW, treat a stdcall symbol name such
  74   // as "Func@0" as undecorated, i.e. a leading underscore must be added.
  75   // For non-MinGW, look for '@' in the whole string and consider "_Func@0"
  76   // as decorated, i.e. don't add any more leading underscores.
  77   // We can't check for a leading underscore here, since function names
  78   // themselves can start with an underscore, while a second one still needs
  79   // to be added.
  80   return Sym.startswith("@") || Sym.contains("@@") || Sym.startswith("?") ||
  81          (!MingwDef && Sym.contains('@'));
  82 }
  83
  84 static Error createError(const Twine &Err) {
  85   return make_error<StringError>(StringRef(Err.str()),
  86                                  object_error::parse_failed);
  87 }
  88
  89 class Lexer {
  90 public:
  91   Lexer(StringRef S) : Buf(S) {}
  92
  93   Token lex() {
  94     Buf = Buf.trim();
  95     if (Buf.empty())
  96       return Token(Eof);
  97
  98     switch (Buf[0]) {
  99     case '\0':
 100       return Token(Eof);
 101     case ';': {
 102       size_t End = Buf.find('\n');
 103       Buf = (End == Buf.npos) ? "" : Buf.drop_front(End);
 104       return lex();
 105     }
 106     case '=':
 107       Buf = Buf.drop_front();
 108       if (Buf.startswith("=")) {
 109         Buf = Buf.drop_front();
 110         return Token(EqualEqual, "==");
 111       }
 112       return Token(Equal, "=");
 113     case ',':
 114       Buf = Buf.drop_front();
 115       return Token(Comma, ",");
 116     case '"': {
 117       StringRef S;
 118       std::tie(S, Buf) = Buf.substr(1).split('"');
 119       return Token(Identifier, S);
 120     }
 121     default: {
 122       size_t End = Buf.find_first_of("=,;\r\n \t\v");
 123       StringRef Word = Buf.substr(0, End);
 124       Kind K = llvm::StringSwitch<Kind>(Word)
 125                    .Case("BASE", KwBase)
 126                    .Case("CONSTANT", KwConstant)
 127                    .Case("DATA", KwData)
 128                    .Case("EXPORTS", KwExports)
 129                    .Case("HEAPSIZE", KwHeapsize)
 130                    .Case("LIBRARY", KwLibrary)
 131                    .Case("NAME", KwName)
 132                    .Case("NONAME", KwNoname)
 133                    .Case("PRIVATE", KwPrivate)
 134                    .Case("STACKSIZE", KwStacksize)
 135                    .Case("VERSION", KwVersion)
 136                    .Default(Identifier);
 137       Buf = (End == Buf.npos) ? "" : Buf.drop_front(End);
 138       return Token(K, Word);
 139     }
 140     }
 141   }
 142
 143 private:
 144   StringRef Buf;
 145 };
 146
 147 class Parser {
 148 public:
 149   explicit Parser(StringRef S, MachineTypes M, bool B)
 150       : Lex(S), Machine(M), MingwDef(B) {}
 151
 152   Expected<COFFModuleDefinition> parse() {
 153     do {
 154       if (Error Err = parseOne())
 155         return std::move(Err);
 156     } while (Tok.K != Eof);
 157     return Info;
 158   }
 159
 160 private:
 161   void read() {
 162     if (Stack.empty()) {
 163       Tok = Lex.lex();
 164       return;
 165     }
 166     Tok = Stack.back();
 167     Stack.pop_back();
 168   }
 169
 170   Error readAsInt(uint64_t *I) {
 171     read();
 172     if (Tok.K != Identifier || Tok.Value.getAsInteger(10, *I))
 173       return createError("integer expected");
 174     return Error::success();
 175   }
 176
 177   Error expect(Kind Expected, StringRef Msg) {
 178     read();
 179     if (Tok.K != Expected)
 180       return createError(Msg);
 181     return Error::success();
 182   }
 183
 184   void unget() { Stack.push_back(Tok); }
 185
 186   Error parseOne() {
 187     read();
 188     switch (Tok.K) {
 189     case Eof:
 190       return Error::success();
 191     case KwExports:
 192       for (;;) {
 193         read();
 194         if (Tok.K != Identifier) {
 195           unget();
 196           return Error::success();
 197         }
 198         if (Error Err = parseExport())
 199           return Err;
 200       }
 201     case KwHeapsize:
 202       return parseNumbers(&Info.HeapReserve, &Info.HeapCommit);
 203     case KwStacksize:
 204       return parseNumbers(&Info.StackReserve, &Info.StackCommit);
 205     case KwLibrary:
 206     case KwName: {
 207       bool IsDll = Tok.K == KwLibrary; // Check before parseName.
 208       std::string Name;
 209       if (Error Err = parseName(&Name, &Info.ImageBase))
 210         return Err;
 211
 212       Info.ImportName = Name;
 213
 214       // Set the output file, but don't override /out if it was already passed.
 215       if (Info.OutputFile.empty()) {
 216         Info.OutputFile = Name;
 217         // Append the appropriate file extension if not already present.
 218         if (!sys::path::has_extension(Name))
 219           Info.OutputFile += IsDll ? ".dll" : ".exe";
 220       }
 221
 222       return Error::success();
 223     }
 224     case KwVersion:
 225       return parseVersion(&Info.MajorImageVersion, &Info.MinorImageVersion);
 226     default:
 227       return createError("unknown directive: " + Tok.Value);
 228     }
 229   }
 230
 231   Error parseExport() {
 232     COFFShortExport E;
 233     E.Name = Tok.Value;
 234     read();
 235     if (Tok.K == Equal) {
 236       read();
 237       if (Tok.K != Identifier)
 238         return createError("identifier expected, but got " + Tok.Value);
 239       E.ExtName = E.Name;
 240       E.Name = Tok.Value;
 241     } else {
 242       unget();
 243     }
 244
 245     if (Machine == IMAGE_FILE_MACHINE_I386) {
 246       if (!isDecorated(E.Name, MingwDef))
 247         E.Name = (std::string("_").append(E.Name));
 248       if (!E.ExtName.empty() && !isDecorated(E.ExtName, MingwDef))
 249         E.ExtName = (std::string("_").append(E.ExtName));
 250     }
 251
 252     for (;;) {
 253       read();
 254       if (Tok.K == Identifier && Tok.Value[0] == '@') {
 255         if (Tok.Value == "@") {
 256           // "foo @ 10"
 257           read();
 258           Tok.Value.getAsInteger(10, E.Ordinal);
 259         } else if (Tok.Value.drop_front().getAsInteger(10, E.Ordinal)) {
 260           // "foo \n @bar" - Not an ordinal modifier at all, but the next
 261           // export (fastcall decorated) - complete the current one.
 262           unget();
 263           Info.Exports.push_back(E);
 264           return Error::success();
 265         }
 266         // "foo @10"
 267         read();
 268         if (Tok.K == KwNoname) {
 269           E.Noname = true;
 270         } else {
 271           unget();
 272         }
 273         continue;
 274       }
 275       if (Tok.K == KwData) {
 276         E.Data = true;
 277         continue;
 278       }
 279       if (Tok.K == KwConstant) {
 280         E.Constant = true;
 281         continue;
 282       }
 283       if (Tok.K == KwPrivate) {
 284         E.Private = true;
 285         continue;
 286       }
 287       if (Tok.K == EqualEqual) {
 288         read();
 289         E.AliasTarget = Tok.Value;
 290         if (Machine == IMAGE_FILE_MACHINE_I386 && !isDecorated(E.AliasTarget, MingwDef))
 291           E.AliasTarget = std::string("_").append(E.AliasTarget);
 292         continue;
 293       }
 294       unget();
 295       Info.Exports.push_back(E);
 296       return Error::success();
 297     }
 298   }
 299
 300   // HEAPSIZE/STACKSIZE reserve[,commit]
 301   Error parseNumbers(uint64_t *Reserve, uint64_t *Commit) {
 302     if (Error Err = readAsInt(Reserve))
 303       return Err;
 304     read();
 305     if (Tok.K != Comma) {
 306       unget();
 307       Commit = nullptr;
 308       return Error::success();
 309     }
 310     if (Error Err = readAsInt(Commit))
 311       return Err;
 312     return Error::success();
 313   }
 314
 315   // NAME outputPath [BASE=address]
 316   Error parseName(std::string *Out, uint64_t *Baseaddr) {
 317     read();
 318     if (Tok.K == Identifier) {
 319       *Out = Tok.Value;
 320     } else {
 321       *Out = "";
 322       unget();
 323       return Error::success();
 324     }
 325     read();
 326     if (Tok.K == KwBase) {
 327       if (Error Err = expect(Equal, "'=' expected"))
 328         return Err;
 329       if (Error Err = readAsInt(Baseaddr))
 330         return Err;
 331     } else {
 332       unget();
 333       *Baseaddr = 0;
 334     }
 335     return Error::success();
 336   }
 337
 338   // VERSION major[.minor]
 339   Error parseVersion(uint32_t *Major, uint32_t *Minor) {
 340     read();
 341     if (Tok.K != Identifier)
 342       return createError("identifier expected, but got " + Tok.Value);
 343     StringRef V1, V2;
 344     std::tie(V1, V2) = Tok.Value.split('.');
 345     if (V1.getAsInteger(10, *Major))
 346       return createError("integer expected, but got " + Tok.Value);
 347     if (V2.empty())
 348       *Minor = 0;
 349     else if (V2.getAsInteger(10, *Minor))
 350       return createError("integer expected, but got " + Tok.Value);
 351     return Error::success();
 352   }
 353
 354   Lexer Lex;
 355   Token Tok;
 356   std::vector<Token> Stack;
 357   MachineTypes Machine;
 358   COFFModuleDefinition Info;
 359   bool MingwDef;
 360 };
 361
 362 Expected<COFFModuleDefinition> parseCOFFModuleDefinition(MemoryBufferRef MB,
 363                                                          MachineTypes Machine,
 364                                                          bool MingwDef) {
 365   return Parser(MB.getBuffer(), Machine, MingwDef).parse();
 366 }
 367
 368 } // namespace object
 369 } // namespace llvm