lib/ExecutionEngine/Interpreter/ExternalFunctions.cpp

   1 //===-- ExternalFunctions.cpp - Implement External Functions --------------===//
   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 //  This file contains both code to deal with invoking "external" functions, but
  11 //  also contains code that implements "exported" external functions.
  12 //
  13 //  There are currently two mechanisms for handling external functions in the
  14 //  Interpreter.  The first is to implement lle_* wrapper functions that are
  15 //  specific to well-known library functions which manually translate the
  16 //  arguments from GenericValues and make the call.  If such a wrapper does
  17 //  not exist, and libffi is available, then the Interpreter will attempt to
  18 //  invoke the function using libffi, after finding its address.
  19 //
  20 //===----------------------------------------------------------------------===//
  21
  22 #include "Interpreter.h"
  23 #include "llvm/DerivedTypes.h"
  24 #include "llvm/Module.h"
  25 #include "llvm/Config/config.h"     // Detect libffi
  26 #include "llvm/Support/Streams.h"
  27 #include "llvm/System/DynamicLibrary.h"
  28 #include "llvm/Target/TargetData.h"
  29 #include "llvm/Support/ManagedStatic.h"
  30 #include <csignal>
  31 #include <cstdio>
  32 #include <map>
  33 #include <cmath>
  34 #include <cstring>
  35
  36 #ifdef HAVE_FFI_CALL
  37 #ifdef HAVE_FFI_H
  38 #include <ffi.h>
  39 #define USE_LIBFFI
  40 #elif HAVE_FFI_FFI_H
  41 #include <ffi/ffi.h>
  42 #define USE_LIBFFI
  43 #endif
  44 #endif
  45
  46 using namespace llvm;
  47
  48 typedef GenericValue (*ExFunc)(const FunctionType *,
  49                                const std::vector<GenericValue> &);
  50 static ManagedStatic<std::map<const Function *, ExFunc> > ExportedFunctions;
  51 static std::map<std::string, ExFunc> FuncNames;
  52
  53 #ifdef USE_LIBFFI
  54 typedef void (*RawFunc)(void);
  55 static ManagedStatic<std::map<const Function *, RawFunc> > RawFunctions;
  56 #endif
  57
  58 static Interpreter *TheInterpreter;
  59
  60 static char getTypeID(const Type *Ty) {
  61   switch (Ty->getTypeID()) {
  62   case Type::VoidTyID:    return 'V';
  63   case Type::IntegerTyID:
  64     switch (cast<IntegerType>(Ty)->getBitWidth()) {
  65       case 1:  return 'o';
  66       case 8:  return 'B';
  67       case 16: return 'S';
  68       case 32: return 'I';
  69       case 64: return 'L';
  70       default: return 'N';
  71     }
  72   case Type::FloatTyID:   return 'F';
  73   case Type::DoubleTyID:  return 'D';
  74   case Type::PointerTyID: return 'P';
  75   case Type::FunctionTyID:return 'M';
  76   case Type::StructTyID:  return 'T';
  77   case Type::ArrayTyID:   return 'A';
  78   case Type::OpaqueTyID:  return 'O';
  79   default: return 'U';
  80   }
  81 }
  82
  83 // Try to find address of external function given a Function object.
  84 // Please note, that interpreter doesn't know how to assemble a
  85 // real call in general case (this is JIT job), that's why it assumes,
  86 // that all external functions has the same (and pretty "general") signature.
  87 // The typical example of such functions are "lle_X_" ones.
  88 static ExFunc lookupFunction(const Function *F) {
  89   // Function not found, look it up... start by figuring out what the
  90   // composite function name should be.
  91   std::string ExtName = "lle_";
  92   const FunctionType *FT = F->getFunctionType();
  93   for (unsigned i = 0, e = FT->getNumContainedTypes(); i != e; ++i)
  94     ExtName += getTypeID(FT->getContainedType(i));
  95   ExtName += "_" + F->getName();
  96
  97   ExFunc FnPtr = FuncNames[ExtName];
  98   if (FnPtr == 0)
  99     FnPtr = FuncNames["lle_X_"+F->getName()];
 100   if (FnPtr == 0)  // Try calling a generic function... if it exists...
 101     FnPtr = (ExFunc)(intptr_t)sys::DynamicLibrary::SearchForAddressOfSymbol(
 102             ("lle_X_"+F->getName()).c_str());
 103   if (FnPtr != 0)
 104     ExportedFunctions->insert(std::make_pair(F, FnPtr));  // Cache for later
 105   return FnPtr;
 106 }
 107
 108 #ifdef USE_LIBFFI
 109 static ffi_type *ffiTypeFor(const Type *Ty) {
 110   switch (Ty->getTypeID()) {
 111     case Type::VoidTyID: return &ffi_type_void;
 112     case Type::IntegerTyID:
 113       switch (cast<IntegerType>(Ty)->getBitWidth()) {
 114         case 8:  return &ffi_type_sint8;
 115         case 16: return &ffi_type_sint16;
 116         case 32: return &ffi_type_sint32;
 117         case 64: return &ffi_type_sint64;
 118       }
 119     case Type::FloatTyID:   return &ffi_type_float;
 120     case Type::DoubleTyID:  return &ffi_type_double;
 121     case Type::PointerTyID: return &ffi_type_pointer;
 122     default: break;
 123   }
 124   // TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
 125   cerr << "Type could not be mapped for use with libffi.\n";
 126   abort();
 127   return NULL;
 128 }
 129
 130 static void *ffiValueFor(const Type *Ty, const GenericValue &AV,
 131                          void *ArgDataPtr) {
 132   switch (Ty->getTypeID()) {
 133     case Type::IntegerTyID:
 134       switch (cast<IntegerType>(Ty)->getBitWidth()) {
 135         case 8: {
 136           int8_t *I8Ptr = (int8_t *) ArgDataPtr;
 137           *I8Ptr = (int8_t) AV.IntVal.getZExtValue();
 138           return ArgDataPtr;
 139         }
 140         case 16: {
 141           int16_t *I16Ptr = (int16_t *) ArgDataPtr;
 142           *I16Ptr = (int16_t) AV.IntVal.getZExtValue();
 143           return ArgDataPtr;
 144         }
 145         case 32: {
 146           int32_t *I32Ptr = (int32_t *) ArgDataPtr;
 147           *I32Ptr = (int32_t) AV.IntVal.getZExtValue();
 148           return ArgDataPtr;
 149         }
 150         case 64: {
 151           int64_t *I64Ptr = (int64_t *) ArgDataPtr;
 152           *I64Ptr = (int64_t) AV.IntVal.getZExtValue();
 153           return ArgDataPtr;
 154         }
 155       }
 156     case Type::FloatTyID: {
 157       float *FloatPtr = (float *) ArgDataPtr;
 158       *FloatPtr = AV.DoubleVal;
 159       return ArgDataPtr;
 160     }
 161     case Type::DoubleTyID: {
 162       double *DoublePtr = (double *) ArgDataPtr;
 163       *DoublePtr = AV.DoubleVal;
 164       return ArgDataPtr;
 165     }
 166     case Type::PointerTyID: {
 167       void **PtrPtr = (void **) ArgDataPtr;
 168       *PtrPtr = GVTOP(AV);
 169       return ArgDataPtr;
 170     }
 171     default: break;
 172   }
 173   // TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
 174   cerr << "Type value could not be mapped for use with libffi.\n";
 175   abort();
 176   return NULL;
 177 }
 178
 179 static bool ffiInvoke(RawFunc Fn, Function *F,
 180                       const std::vector<GenericValue> &ArgVals,
 181                       const TargetData *TD, GenericValue &Result) {
 182   ffi_cif cif;
 183   const FunctionType *FTy = F->getFunctionType();
 184   const unsigned NumArgs = F->arg_size();
 185
 186   // TODO: We don't have type information about the remaining arguments, because
 187   // this information is never passed into ExecutionEngine::runFunction().
 188   if (ArgVals.size() > NumArgs && F->isVarArg()) {
 189     cerr << "Calling external var arg function '" << F->getName()
 190          << "' is not supported by the Interpreter.\n";
 191     abort();
 192   }
 193
 194   unsigned ArgBytes = 0;
 195
 196   std::vector<ffi_type*> args(NumArgs);
 197   for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
 198        A != E; ++A) {
 199     const unsigned ArgNo = A->getArgNo();
 200     const Type *ArgTy = FTy->getParamType(ArgNo);
 201     args[ArgNo] = ffiTypeFor(ArgTy);
 202     ArgBytes += TD->getTypeStoreSize(ArgTy);
 203   }
 204
 205   uint8_t *ArgData = (uint8_t*) alloca(ArgBytes);
 206   uint8_t *ArgDataPtr = ArgData;
 207   std::vector<void*> values(NumArgs);
 208   for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
 209        A != E; ++A) {
 210     const unsigned ArgNo = A->getArgNo();
 211     const Type *ArgTy = FTy->getParamType(ArgNo);
 212     values[ArgNo] = ffiValueFor(ArgTy, ArgVals[ArgNo], ArgDataPtr);
 213     ArgDataPtr += TD->getTypeStoreSize(ArgTy);
 214   }
 215
 216   const Type *RetTy = FTy->getReturnType();
 217   ffi_type *rtype = ffiTypeFor(RetTy);
 218
 219   if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, NumArgs, rtype, &args[0]) == FFI_OK) {
 220     void *ret = NULL;
 221     if (RetTy->getTypeID() != Type::VoidTyID)
 222       ret = alloca(TD->getTypeStoreSize(RetTy));
 223     ffi_call(&cif, Fn, ret, &values[0]);
 224     switch (RetTy->getTypeID()) {
 225       case Type::IntegerTyID:
 226         switch (cast<IntegerType>(RetTy)->getBitWidth()) {
 227           case 8:  Result.IntVal = APInt(8 , *(int8_t *) ret); break;
 228           case 16: Result.IntVal = APInt(16, *(int16_t*) ret); break;
 229           case 32: Result.IntVal = APInt(32, *(int32_t*) ret); break;
 230           case 64: Result.IntVal = APInt(64, *(int64_t*) ret); break;
 231         }
 232         break;
 233       case Type::FloatTyID:   Result.FloatVal   = *(float *) ret; break;
 234       case Type::DoubleTyID:  Result.DoubleVal  = *(double*) ret; break;
 235       case Type::PointerTyID: Result.PointerVal = *(void **) ret; break;
 236       default: break;
 237     }
 238     return true;
 239   }
 240
 241   return false;
 242 }
 243 #endif // USE_LIBFFI
 244
 245 GenericValue Interpreter::callExternalFunction(Function *F,
 246                                      const std::vector<GenericValue> &ArgVals) {
 247   TheInterpreter = this;
 248
 249   // Do a lookup to see if the function is in our cache... this should just be a
 250   // deferred annotation!
 251   std::map<const Function *, ExFunc>::iterator FI = ExportedFunctions->find(F);
 252   if (ExFunc Fn = (FI == ExportedFunctions->end()) ? lookupFunction(F)
 253                                                    : FI->second)
 254     return Fn(F->getFunctionType(), ArgVals);
 255
 256 #ifdef USE_LIBFFI
 257   std::map<const Function *, RawFunc>::iterator RF = RawFunctions->find(F);
 258   RawFunc RawFn;
 259   if (RF == RawFunctions->end()) {
 260     RawFn = (RawFunc)(intptr_t)
 261       sys::DynamicLibrary::SearchForAddressOfSymbol(F->getName());
 262     if (RawFn != 0)
 263       RawFunctions->insert(std::make_pair(F, RawFn));  // Cache for later
 264   } else {
 265     RawFn = RF->second;
 266   }
 267
 268   GenericValue Result;
 269   if (RawFn != 0 && ffiInvoke(RawFn, F, ArgVals, getTargetData(), Result))
 270     return Result;
 271 #endif // USE_LIBFFI
 272
 273   cerr << "Tried to execute an unknown external function: "
 274        << F->getType()->getDescription() << " " << F->getName() << "\n";
 275   if (F->getName() != "__main")
 276     abort();
 277   return GenericValue();
 278 }
 279
 280
 281 //===----------------------------------------------------------------------===//
 282 //  Functions "exported" to the running application...
 283 //
 284 extern "C" {  // Don't add C++ manglings to llvm mangling :)
 285
 286 // void atexit(Function*)
 287 GenericValue lle_X_atexit(const FunctionType *FT,
 288                           const std::vector<GenericValue> &Args) {
 289   assert(Args.size() == 1);
 290   TheInterpreter->addAtExitHandler((Function*)GVTOP(Args[0]));
 291   GenericValue GV;
 292   GV.IntVal = 0;
 293   return GV;
 294 }
 295
 296 // void exit(int)
 297 GenericValue lle_X_exit(const FunctionType *FT,
 298                         const std::vector<GenericValue> &Args) {
 299   TheInterpreter->exitCalled(Args[0]);
 300   return GenericValue();
 301 }
 302
 303 // void abort(void)
 304 GenericValue lle_X_abort(const FunctionType *FT,
 305                          const std::vector<GenericValue> &Args) {
 306   raise (SIGABRT);
 307   return GenericValue();
 308 }
 309
 310 // int sprintf(char *, const char *, ...) - a very rough implementation to make
 311 // output useful.
 312 GenericValue lle_X_sprintf(const FunctionType *FT,
 313                            const std::vector<GenericValue> &Args) {
 314   char *OutputBuffer = (char *)GVTOP(Args[0]);
 315   const char *FmtStr = (const char *)GVTOP(Args[1]);
 316   unsigned ArgNo = 2;
 317
 318   // printf should return # chars printed.  This is completely incorrect, but
 319   // close enough for now.
 320   GenericValue GV;
 321   GV.IntVal = APInt(32, strlen(FmtStr));
 322   while (1) {
 323     switch (*FmtStr) {
 324     case 0: return GV;             // Null terminator...
 325     default:                       // Normal nonspecial character
 326       sprintf(OutputBuffer++, "%c", *FmtStr++);
 327       break;
 328     case '\\': {                   // Handle escape codes
 329       sprintf(OutputBuffer, "%c%c", *FmtStr, *(FmtStr+1));
 330       FmtStr += 2; OutputBuffer += 2;
 331       break;
 332     }
 333     case '%': {                    // Handle format specifiers
 334       char FmtBuf[100] = "", Buffer[1000] = "";
 335       char *FB = FmtBuf;
 336       *FB++ = *FmtStr++;
 337       char Last = *FB++ = *FmtStr++;
 338       unsigned HowLong = 0;
 339       while (Last != 'c' && Last != 'd' && Last != 'i' && Last != 'u' &&
 340              Last != 'o' && Last != 'x' && Last != 'X' && Last != 'e' &&
 341              Last != 'E' && Last != 'g' && Last != 'G' && Last != 'f' &&
 342              Last != 'p' && Last != 's' && Last != '%') {
 343         if (Last == 'l' || Last == 'L') HowLong++;  // Keep track of l's
 344         Last = *FB++ = *FmtStr++;
 345       }
 346       *FB = 0;
 347
 348       switch (Last) {
 349       case '%':
 350         strcpy(Buffer, "%"); break;
 351       case 'c':
 352         sprintf(Buffer, FmtBuf, uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
 353         break;
 354       case 'd': case 'i':
 355       case 'u': case 'o':
 356       case 'x': case 'X':
 357         if (HowLong >= 1) {
 358           if (HowLong == 1 &&
 359               TheInterpreter->getTargetData()->getPointerSizeInBits() == 64 &&
 360               sizeof(long) < sizeof(int64_t)) {
 361             // Make sure we use %lld with a 64 bit argument because we might be
 362             // compiling LLI on a 32 bit compiler.
 363             unsigned Size = strlen(FmtBuf);
 364             FmtBuf[Size] = FmtBuf[Size-1];
 365             FmtBuf[Size+1] = 0;
 366             FmtBuf[Size-1] = 'l';
 367           }
 368           sprintf(Buffer, FmtBuf, Args[ArgNo++].IntVal.getZExtValue());
 369         } else
 370           sprintf(Buffer, FmtBuf,uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
 371         break;
 372       case 'e': case 'E': case 'g': case 'G': case 'f':
 373         sprintf(Buffer, FmtBuf, Args[ArgNo++].DoubleVal); break;
 374       case 'p':
 375         sprintf(Buffer, FmtBuf, (void*)GVTOP(Args[ArgNo++])); break;
 376       case 's':
 377         sprintf(Buffer, FmtBuf, (char*)GVTOP(Args[ArgNo++])); break;
 378       default:  cerr << "<unknown printf code '" << *FmtStr << "'!>";
 379         ArgNo++; break;
 380       }
 381       strcpy(OutputBuffer, Buffer);
 382       OutputBuffer += strlen(Buffer);
 383       }
 384       break;
 385     }
 386   }
 387   return GV;
 388 }
 389
 390 // int printf(const char *, ...) - a very rough implementation to make output
 391 // useful.
 392 GenericValue lle_X_printf(const FunctionType *FT,
 393                           const std::vector<GenericValue> &Args) {
 394   char Buffer[10000];
 395   std::vector<GenericValue> NewArgs;
 396   NewArgs.push_back(PTOGV((void*)&Buffer[0]));
 397   NewArgs.insert(NewArgs.end(), Args.begin(), Args.end());
 398   GenericValue GV = lle_X_sprintf(FT, NewArgs);
 399   cout << Buffer;
 400   return GV;
 401 }
 402
 403 static void ByteswapSCANFResults(const char *Fmt, void *Arg0, void *Arg1,
 404                                  void *Arg2, void *Arg3, void *Arg4, void *Arg5,
 405                                  void *Arg6, void *Arg7, void *Arg8) {
 406   void *Args[] = { Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8, 0 };
 407
 408   // Loop over the format string, munging read values as appropriate (performs
 409   // byteswaps as necessary).
 410   unsigned ArgNo = 0;
 411   while (*Fmt) {
 412     if (*Fmt++ == '%') {
 413       // Read any flag characters that may be present...
 414       bool Suppress = false;
 415       bool Half = false;
 416       bool Long = false;
 417       bool LongLong = false;  // long long or long double
 418
 419       while (1) {
 420         switch (*Fmt++) {
 421         case '*': Suppress = true; break;
 422         case 'a': /*Allocate = true;*/ break;  // We don't need to track this
 423         case 'h': Half = true; break;
 424         case 'l': Long = true; break;
 425         case 'q':
 426         case 'L': LongLong = true; break;
 427         default:
 428           if (Fmt[-1] > '9' || Fmt[-1] < '0')   // Ignore field width specs
 429             goto Out;
 430         }
 431       }
 432     Out:
 433
 434       // Read the conversion character
 435       if (!Suppress && Fmt[-1] != '%') { // Nothing to do?
 436         unsigned Size = 0;
 437         const Type *Ty = 0;
 438
 439         switch (Fmt[-1]) {
 440         case 'i': case 'o': case 'u': case 'x': case 'X': case 'n': case 'p':
 441         case 'd':
 442           if (Long || LongLong) {
 443             Size = 8; Ty = Type::Int64Ty;
 444           } else if (Half) {
 445             Size = 4; Ty = Type::Int16Ty;
 446           } else {
 447             Size = 4; Ty = Type::Int32Ty;
 448           }
 449           break;
 450
 451         case 'e': case 'g': case 'E':
 452         case 'f':
 453           if (Long || LongLong) {
 454             Size = 8; Ty = Type::DoubleTy;
 455           } else {
 456             Size = 4; Ty = Type::FloatTy;
 457           }
 458           break;
 459
 460         case 's': case 'c': case '[':  // No byteswap needed
 461           Size = 1;
 462           Ty = Type::Int8Ty;
 463           break;
 464
 465         default: break;
 466         }
 467
 468         if (Size) {
 469           GenericValue GV;
 470           void *Arg = Args[ArgNo++];
 471           memcpy(&GV, Arg, Size);
 472           TheInterpreter->StoreValueToMemory(GV, (GenericValue*)Arg, Ty);
 473         }
 474       }
 475     }
 476   }
 477 }
 478
 479 // int sscanf(const char *format, ...);
 480 GenericValue lle_X_sscanf(const FunctionType *FT,
 481                           const std::vector<GenericValue> &args) {
 482   assert(args.size() < 10 && "Only handle up to 10 args to sscanf right now!");
 483
 484   char *Args[10];
 485   for (unsigned i = 0; i < args.size(); ++i)
 486     Args[i] = (char*)GVTOP(args[i]);
 487
 488   GenericValue GV;
 489   GV.IntVal = APInt(32, sscanf(Args[0], Args[1], Args[2], Args[3], Args[4],
 490                         Args[5], Args[6], Args[7], Args[8], Args[9]));
 491   ByteswapSCANFResults(Args[1], Args[2], Args[3], Args[4],
 492                        Args[5], Args[6], Args[7], Args[8], Args[9], 0);
 493   return GV;
 494 }
 495
 496 // int scanf(const char *format, ...);
 497 GenericValue lle_X_scanf(const FunctionType *FT,
 498                          const std::vector<GenericValue> &args) {
 499   assert(args.size() < 10 && "Only handle up to 10 args to scanf right now!");
 500
 501   char *Args[10];
 502   for (unsigned i = 0; i < args.size(); ++i)
 503     Args[i] = (char*)GVTOP(args[i]);
 504
 505   GenericValue GV;
 506   GV.IntVal = APInt(32, scanf( Args[0], Args[1], Args[2], Args[3], Args[4],
 507                         Args[5], Args[6], Args[7], Args[8], Args[9]));
 508   ByteswapSCANFResults(Args[0], Args[1], Args[2], Args[3], Args[4],
 509                        Args[5], Args[6], Args[7], Args[8], Args[9]);
 510   return GV;
 511 }
 512
 513 // int fprintf(FILE *, const char *, ...) - a very rough implementation to make
 514 // output useful.
 515 GenericValue lle_X_fprintf(const FunctionType *FT,
 516                            const std::vector<GenericValue> &Args) {
 517   assert(Args.size() >= 2);
 518   char Buffer[10000];
 519   std::vector<GenericValue> NewArgs;
 520   NewArgs.push_back(PTOGV(Buffer));
 521   NewArgs.insert(NewArgs.end(), Args.begin()+1, Args.end());
 522   GenericValue GV = lle_X_sprintf(FT, NewArgs);
 523
 524   fputs(Buffer, (FILE *) GVTOP(Args[0]));
 525   return GV;
 526 }
 527
 528 } // End extern "C"
 529
 530
 531 void Interpreter::initializeExternalFunctions() {
 532   FuncNames["lle_X_atexit"]       = lle_X_atexit;
 533   FuncNames["lle_X_exit"]         = lle_X_exit;
 534   FuncNames["lle_X_abort"]        = lle_X_abort;
 535
 536   FuncNames["lle_X_printf"]       = lle_X_printf;
 537   FuncNames["lle_X_sprintf"]      = lle_X_sprintf;
 538   FuncNames["lle_X_sscanf"]       = lle_X_sscanf;
 539   FuncNames["lle_X_scanf"]        = lle_X_scanf;
 540   FuncNames["lle_X_fprintf"]      = lle_X_fprintf;
 541 }
 542