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/ErrorHandling.h"
  27 #include "llvm/System/DynamicLibrary.h"
  28 #include "llvm/Target/TargetData.h"
  29 #include "llvm/Support/ManagedStatic.h"
  30 #include "llvm/System/Mutex.h"
  31 #include <csignal>
  32 #include <cstdio>
  33 #include <map>
  34 #include <cmath>
  35 #include <cstring>
  36
  37 #ifdef HAVE_FFI_CALL
  38 #ifdef HAVE_FFI_H
  39 #include <ffi.h>
  40 #define USE_LIBFFI
  41 #elif HAVE_FFI_FFI_H
  42 #include <ffi/ffi.h>
  43 #define USE_LIBFFI
  44 #endif
  45 #endif
  46
  47 using namespace llvm;
  48
  49 static ManagedStatic<sys::Mutex> FunctionsLock;
  50
  51 typedef GenericValue (*ExFunc)(const FunctionType *,
  52                                const std::vector<GenericValue> &);
  53 static ManagedStatic<std::map<const Function *, ExFunc> > ExportedFunctions;
  54 static std::map<std::string, ExFunc> FuncNames;
  55
  56 #ifdef USE_LIBFFI
  57 typedef void (*RawFunc)();
  58 static ManagedStatic<std::map<const Function *, RawFunc> > RawFunctions;
  59 #endif
  60
  61 static Interpreter *TheInterpreter;
  62
  63 static char getTypeID(const Type *Ty) {
  64   switch (Ty->getTypeID()) {
  65   case Type::VoidTyID:    return 'V';
  66   case Type::IntegerTyID:
  67     switch (cast<IntegerType>(Ty)->getBitWidth()) {
  68       case 1:  return 'o';
  69       case 8:  return 'B';
  70       case 16: return 'S';
  71       case 32: return 'I';
  72       case 64: return 'L';
  73       default: return 'N';
  74     }
  75   case Type::FloatTyID:   return 'F';
  76   case Type::DoubleTyID:  return 'D';
  77   case Type::PointerTyID: return 'P';
  78   case Type::FunctionTyID:return 'M';
  79   case Type::StructTyID:  return 'T';
  80   case Type::ArrayTyID:   return 'A';
  81   case Type::OpaqueTyID:  return 'O';
  82   default: return 'U';
  83   }
  84 }
  85
  86 // Try to find address of external function given a Function object.
  87 // Please note, that interpreter doesn't know how to assemble a
  88 // real call in general case (this is JIT job), that's why it assumes,
  89 // that all external functions has the same (and pretty "general") signature.
  90 // The typical example of such functions are "lle_X_" ones.
  91 static ExFunc lookupFunction(const Function *F) {
  92   // Function not found, look it up... start by figuring out what the
  93   // composite function name should be.
  94   std::string ExtName = "lle_";
  95   const FunctionType *FT = F->getFunctionType();
  96   for (unsigned i = 0, e = FT->getNumContainedTypes(); i != e; ++i)
  97     ExtName += getTypeID(FT->getContainedType(i));
  98   ExtName + "_" + F->getNameStr();
  99
 100   sys::ScopedLock Writer(*FunctionsLock);
 101   ExFunc FnPtr = FuncNames[ExtName];
 102   if (FnPtr == 0)
 103     FnPtr = FuncNames["lle_X_" + F->getNameStr()];
 104   if (FnPtr == 0)  // Try calling a generic function... if it exists...
 105     FnPtr = (ExFunc)(intptr_t)
 106       sys::DynamicLibrary::SearchForAddressOfSymbol("lle_X_"+F->getNameStr());
 107   if (FnPtr != 0)
 108     ExportedFunctions->insert(std::make_pair(F, FnPtr));  // Cache for later
 109   return FnPtr;
 110 }
 111
 112 #ifdef USE_LIBFFI
 113 static ffi_type *ffiTypeFor(const Type *Ty) {
 114   switch (Ty->getTypeID()) {
 115     case Type::VoidTyID: return &ffi_type_void;
 116     case Type::IntegerTyID:
 117       switch (cast<IntegerType>(Ty)->getBitWidth()) {
 118         case 8:  return &ffi_type_sint8;
 119         case 16: return &ffi_type_sint16;
 120         case 32: return &ffi_type_sint32;
 121         case 64: return &ffi_type_sint64;
 122       }
 123     case Type::FloatTyID:   return &ffi_type_float;
 124     case Type::DoubleTyID:  return &ffi_type_double;
 125     case Type::PointerTyID: return &ffi_type_pointer;
 126     default: break;
 127   }
 128   // TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
 129   report_fatal_error("Type could not be mapped for use with libffi.");
 130   return NULL;
 131 }
 132
 133 static void *ffiValueFor(const Type *Ty, const GenericValue &AV,
 134                          void *ArgDataPtr) {
 135   switch (Ty->getTypeID()) {
 136     case Type::IntegerTyID:
 137       switch (cast<IntegerType>(Ty)->getBitWidth()) {
 138         case 8: {
 139           int8_t *I8Ptr = (int8_t *) ArgDataPtr;
 140           *I8Ptr = (int8_t) AV.IntVal.getZExtValue();
 141           return ArgDataPtr;
 142         }
 143         case 16: {
 144           int16_t *I16Ptr = (int16_t *) ArgDataPtr;
 145           *I16Ptr = (int16_t) AV.IntVal.getZExtValue();
 146           return ArgDataPtr;
 147         }
 148         case 32: {
 149           int32_t *I32Ptr = (int32_t *) ArgDataPtr;
 150           *I32Ptr = (int32_t) AV.IntVal.getZExtValue();
 151           return ArgDataPtr;
 152         }
 153         case 64: {
 154           int64_t *I64Ptr = (int64_t *) ArgDataPtr;
 155           *I64Ptr = (int64_t) AV.IntVal.getZExtValue();
 156           return ArgDataPtr;
 157         }
 158       }
 159     case Type::FloatTyID: {
 160       float *FloatPtr = (float *) ArgDataPtr;
 161       *FloatPtr = AV.FloatVal;
 162       return ArgDataPtr;
 163     }
 164     case Type::DoubleTyID: {
 165       double *DoublePtr = (double *) ArgDataPtr;
 166       *DoublePtr = AV.DoubleVal;
 167       return ArgDataPtr;
 168     }
 169     case Type::PointerTyID: {
 170       void **PtrPtr = (void **) ArgDataPtr;
 171       *PtrPtr = GVTOP(AV);
 172       return ArgDataPtr;
 173     }
 174     default: break;
 175   }
 176   // TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
 177   report_fatal_error("Type value could not be mapped for use with libffi.");
 178   return NULL;
 179 }
 180
 181 static bool ffiInvoke(RawFunc Fn, Function *F,
 182                       const std::vector<GenericValue> &ArgVals,
 183                       const TargetData *TD, GenericValue &Result) {
 184   ffi_cif cif;
 185   const FunctionType *FTy = F->getFunctionType();
 186   const unsigned NumArgs = F->arg_size();
 187
 188   // TODO: We don't have type information about the remaining arguments, because
 189   // this information is never passed into ExecutionEngine::runFunction().
 190   if (ArgVals.size() > NumArgs && F->isVarArg()) {
 191     report_fatal_error("Calling external var arg function '" + F->getName()
 192                       + "' is not supported by the Interpreter.");
 193   }
 194
 195   unsigned ArgBytes = 0;
 196
 197   std::vector<ffi_type*> args(NumArgs);
 198   for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
 199        A != E; ++A) {
 200     const unsigned ArgNo = A->getArgNo();
 201     const Type *ArgTy = FTy->getParamType(ArgNo);
 202     args[ArgNo] = ffiTypeFor(ArgTy);
 203     ArgBytes += TD->getTypeStoreSize(ArgTy);
 204   }
 205
 206   SmallVector<uint8_t, 128> ArgData;
 207   ArgData.resize(ArgBytes);
 208   uint8_t *ArgDataPtr = ArgData.data();
 209   SmallVector<void*, 16> values(NumArgs);
 210   for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
 211        A != E; ++A) {
 212     const unsigned ArgNo = A->getArgNo();
 213     const Type *ArgTy = FTy->getParamType(ArgNo);
 214     values[ArgNo] = ffiValueFor(ArgTy, ArgVals[ArgNo], ArgDataPtr);
 215     ArgDataPtr += TD->getTypeStoreSize(ArgTy);
 216   }
 217
 218   const Type *RetTy = FTy->getReturnType();
 219   ffi_type *rtype = ffiTypeFor(RetTy);
 220
 221   if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, NumArgs, rtype, &args[0]) == FFI_OK) {
 222     SmallVector<uint8_t, 128> ret;
 223     if (RetTy->getTypeID() != Type::VoidTyID)
 224       ret.resize(TD->getTypeStoreSize(RetTy));
 225     ffi_call(&cif, Fn, ret.data(), values.data());
 226     switch (RetTy->getTypeID()) {
 227       case Type::IntegerTyID:
 228         switch (cast<IntegerType>(RetTy)->getBitWidth()) {
 229           case 8:  Result.IntVal = APInt(8 , *(int8_t *) ret.data()); break;
 230           case 16: Result.IntVal = APInt(16, *(int16_t*) ret.data()); break;
 231           case 32: Result.IntVal = APInt(32, *(int32_t*) ret.data()); break;
 232           case 64: Result.IntVal = APInt(64, *(int64_t*) ret.data()); break;
 233         }
 234         break;
 235       case Type::FloatTyID:   Result.FloatVal   = *(float *) ret.data(); break;
 236       case Type::DoubleTyID:  Result.DoubleVal  = *(double*) ret.data(); break;
 237       case Type::PointerTyID: Result.PointerVal = *(void **) ret.data(); break;
 238       default: break;
 239     }
 240     return true;
 241   }
 242
 243   return false;
 244 }
 245 #endif // USE_LIBFFI
 246
 247 GenericValue Interpreter::callExternalFunction(Function *F,
 248                                      const std::vector<GenericValue> &ArgVals) {
 249   TheInterpreter = this;
 250
 251   FunctionsLock->acquire();
 252
 253   // Do a lookup to see if the function is in our cache... this should just be a
 254   // deferred annotation!
 255   std::map<const Function *, ExFunc>::iterator FI = ExportedFunctions->find(F);
 256   if (ExFunc Fn = (FI == ExportedFunctions->end()) ? lookupFunction(F)
 257                                                    : FI->second) {
 258     FunctionsLock->release();
 259     return Fn(F->getFunctionType(), ArgVals);
 260   }
 261
 262 #ifdef USE_LIBFFI
 263   std::map<const Function *, RawFunc>::iterator RF = RawFunctions->find(F);
 264   RawFunc RawFn;
 265   if (RF == RawFunctions->end()) {
 266     RawFn = (RawFunc)(intptr_t)
 267       sys::DynamicLibrary::SearchForAddressOfSymbol(F->getName());
 268     if (!RawFn)
 269       RawFn = (RawFunc)(intptr_t)getPointerToGlobalIfAvailable(F);
 270     if (RawFn != 0)
 271       RawFunctions->insert(std::make_pair(F, RawFn));  // Cache for later
 272   } else {
 273     RawFn = RF->second;
 274   }
 275
 276   FunctionsLock->release();
 277
 278   GenericValue Result;
 279   if (RawFn != 0 && ffiInvoke(RawFn, F, ArgVals, getTargetData(), Result))
 280     return Result;
 281 #endif // USE_LIBFFI
 282
 283   if (F->getName() == "__main")
 284     errs() << "Tried to execute an unknown external function: "
 285       << F->getType()->getDescription() << " __main\n";
 286   else
 287     report_fatal_error("Tried to execute an unknown external function: " +
 288                       F->getType()->getDescription() + " " +F->getName());
 289 #ifndef USE_LIBFFI
 290   errs() << "Recompiling LLVM with --enable-libffi might help.\n";
 291 #endif
 292   return GenericValue();
 293 }
 294
 295
 296 //===----------------------------------------------------------------------===//
 297 //  Functions "exported" to the running application...
 298 //
 299
 300 // Visual Studio warns about returning GenericValue in extern "C" linkage
 301 #ifdef _MSC_VER
 302     #pragma warning(disable : 4190)
 303 #endif
 304
 305 extern "C" {  // Don't add C++ manglings to llvm mangling :)
 306
 307 // void atexit(Function*)
 308 GenericValue lle_X_atexit(const FunctionType *FT,
 309                           const std::vector<GenericValue> &Args) {
 310   assert(Args.size() == 1);
 311   TheInterpreter->addAtExitHandler((Function*)GVTOP(Args[0]));
 312   GenericValue GV;
 313   GV.IntVal = 0;
 314   return GV;
 315 }
 316
 317 // void exit(int)
 318 GenericValue lle_X_exit(const FunctionType *FT,
 319                         const std::vector<GenericValue> &Args) {
 320   TheInterpreter->exitCalled(Args[0]);
 321   return GenericValue();
 322 }
 323
 324 // void abort(void)
 325 GenericValue lle_X_abort(const FunctionType *FT,
 326                          const std::vector<GenericValue> &Args) {
 327   //FIXME: should we report or raise here?
 328   //report_fatal_error("Interpreted program raised SIGABRT");
 329   raise (SIGABRT);
 330   return GenericValue();
 331 }
 332
 333 // int sprintf(char *, const char *, ...) - a very rough implementation to make
 334 // output useful.
 335 GenericValue lle_X_sprintf(const FunctionType *FT,
 336                            const std::vector<GenericValue> &Args) {
 337   char *OutputBuffer = (char *)GVTOP(Args[0]);
 338   const char *FmtStr = (const char *)GVTOP(Args[1]);
 339   unsigned ArgNo = 2;
 340
 341   // printf should return # chars printed.  This is completely incorrect, but
 342   // close enough for now.
 343   GenericValue GV;
 344   GV.IntVal = APInt(32, strlen(FmtStr));
 345   while (1) {
 346     switch (*FmtStr) {
 347     case 0: return GV;             // Null terminator...
 348     default:                       // Normal nonspecial character
 349       sprintf(OutputBuffer++, "%c", *FmtStr++);
 350       break;
 351     case '\\': {                   // Handle escape codes
 352       sprintf(OutputBuffer, "%c%c", *FmtStr, *(FmtStr+1));
 353       FmtStr += 2; OutputBuffer += 2;
 354       break;
 355     }
 356     case '%': {                    // Handle format specifiers
 357       char FmtBuf[100] = "", Buffer[1000] = "";
 358       char *FB = FmtBuf;
 359       *FB++ = *FmtStr++;
 360       char Last = *FB++ = *FmtStr++;
 361       unsigned HowLong = 0;
 362       while (Last != 'c' && Last != 'd' && Last != 'i' && Last != 'u' &&
 363              Last != 'o' && Last != 'x' && Last != 'X' && Last != 'e' &&
 364              Last != 'E' && Last != 'g' && Last != 'G' && Last != 'f' &&
 365              Last != 'p' && Last != 's' && Last != '%') {
 366         if (Last == 'l' || Last == 'L') HowLong++;  // Keep track of l's
 367         Last = *FB++ = *FmtStr++;
 368       }
 369       *FB = 0;
 370
 371       switch (Last) {
 372       case '%':
 373         memcpy(Buffer, "%", 2); break;
 374       case 'c':
 375         sprintf(Buffer, FmtBuf, uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
 376         break;
 377       case 'd': case 'i':
 378       case 'u': case 'o':
 379       case 'x': case 'X':
 380         if (HowLong >= 1) {
 381           if (HowLong == 1 &&
 382               TheInterpreter->getTargetData()->getPointerSizeInBits() == 64 &&
 383               sizeof(long) < sizeof(int64_t)) {
 384             // Make sure we use %lld with a 64 bit argument because we might be
 385             // compiling LLI on a 32 bit compiler.
 386             unsigned Size = strlen(FmtBuf);
 387             FmtBuf[Size] = FmtBuf[Size-1];
 388             FmtBuf[Size+1] = 0;
 389             FmtBuf[Size-1] = 'l';
 390           }
 391           sprintf(Buffer, FmtBuf, Args[ArgNo++].IntVal.getZExtValue());
 392         } else
 393           sprintf(Buffer, FmtBuf,uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
 394         break;
 395       case 'e': case 'E': case 'g': case 'G': case 'f':
 396         sprintf(Buffer, FmtBuf, Args[ArgNo++].DoubleVal); break;
 397       case 'p':
 398         sprintf(Buffer, FmtBuf, (void*)GVTOP(Args[ArgNo++])); break;
 399       case 's':
 400         sprintf(Buffer, FmtBuf, (char*)GVTOP(Args[ArgNo++])); break;
 401       default:
 402         errs() << "<unknown printf code '" << *FmtStr << "'!>";
 403         ArgNo++; break;
 404       }
 405       size_t Len = strlen(Buffer);
 406       memcpy(OutputBuffer, Buffer, Len + 1);
 407       OutputBuffer += Len;
 408       }
 409       break;
 410     }
 411   }
 412   return GV;
 413 }
 414
 415 // int printf(const char *, ...) - a very rough implementation to make output
 416 // useful.
 417 GenericValue lle_X_printf(const FunctionType *FT,
 418                           const std::vector<GenericValue> &Args) {
 419   char Buffer[10000];
 420   std::vector<GenericValue> NewArgs;
 421   NewArgs.push_back(PTOGV((void*)&Buffer[0]));
 422   NewArgs.insert(NewArgs.end(), Args.begin(), Args.end());
 423   GenericValue GV = lle_X_sprintf(FT, NewArgs);
 424   outs() << Buffer;
 425   return GV;
 426 }
 427
 428 // int sscanf(const char *format, ...);
 429 GenericValue lle_X_sscanf(const FunctionType *FT,
 430                           const std::vector<GenericValue> &args) {
 431   assert(args.size() < 10 && "Only handle up to 10 args to sscanf right now!");
 432
 433   char *Args[10];
 434   for (unsigned i = 0; i < args.size(); ++i)
 435     Args[i] = (char*)GVTOP(args[i]);
 436
 437   GenericValue GV;
 438   GV.IntVal = APInt(32, sscanf(Args[0], Args[1], Args[2], Args[3], Args[4],
 439                         Args[5], Args[6], Args[7], Args[8], Args[9]));
 440   return GV;
 441 }
 442
 443 // int scanf(const char *format, ...);
 444 GenericValue lle_X_scanf(const FunctionType *FT,
 445                          const std::vector<GenericValue> &args) {
 446   assert(args.size() < 10 && "Only handle up to 10 args to scanf right now!");
 447
 448   char *Args[10];
 449   for (unsigned i = 0; i < args.size(); ++i)
 450     Args[i] = (char*)GVTOP(args[i]);
 451
 452   GenericValue GV;
 453   GV.IntVal = APInt(32, scanf( Args[0], Args[1], Args[2], Args[3], Args[4],
 454                         Args[5], Args[6], Args[7], Args[8], Args[9]));
 455   return GV;
 456 }
 457
 458 // int fprintf(FILE *, const char *, ...) - a very rough implementation to make
 459 // output useful.
 460 GenericValue lle_X_fprintf(const FunctionType *FT,
 461                            const std::vector<GenericValue> &Args) {
 462   assert(Args.size() >= 2);
 463   char Buffer[10000];
 464   std::vector<GenericValue> NewArgs;
 465   NewArgs.push_back(PTOGV(Buffer));
 466   NewArgs.insert(NewArgs.end(), Args.begin()+1, Args.end());
 467   GenericValue GV = lle_X_sprintf(FT, NewArgs);
 468
 469   fputs(Buffer, (FILE *) GVTOP(Args[0]));
 470   return GV;
 471 }
 472
 473 } // End extern "C"
 474
 475 // Done with externals; turn the warning back on
 476 #ifdef _MSC_VER
 477     #pragma warning(default: 4190)
 478 #endif
 479
 480
 481 void Interpreter::initializeExternalFunctions() {
 482   sys::ScopedLock Writer(*FunctionsLock);
 483   FuncNames["lle_X_atexit"]       = lle_X_atexit;
 484   FuncNames["lle_X_exit"]         = lle_X_exit;
 485   FuncNames["lle_X_abort"]        = lle_X_abort;
 486
 487   FuncNames["lle_X_printf"]       = lle_X_printf;
 488   FuncNames["lle_X_sprintf"]      = lle_X_sprintf;
 489   FuncNames["lle_X_sscanf"]       = lle_X_sscanf;
 490   FuncNames["lle_X_scanf"]        = lle_X_scanf;
 491   FuncNames["lle_X_fprintf"]      = lle_X_fprintf;
 492 }