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