src/llvm/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/Config/config.h"     // Detect libffi
  24 #include "llvm/IR/DataLayout.h"
  25 #include "llvm/IR/DerivedTypes.h"
  26 #include "llvm/IR/Module.h"
  27 #include "llvm/Support/DynamicLibrary.h"
  28 #include "llvm/Support/ErrorHandling.h"
  29 #include "llvm/Support/ManagedStatic.h"
  30 #include "llvm/Support/Mutex.h"
  31 #include "llvm/Support/UniqueLock.h"
  32 #include <cmath>
  33 #include <csignal>
  34 #include <cstdio>
  35 #include <cstring>
  36 #include <map>
  37
  38 #ifdef HAVE_FFI_CALL
  39 #ifdef HAVE_FFI_H
  40 #include <ffi.h>
  41 #define USE_LIBFFI
  42 #elif HAVE_FFI_FFI_H
  43 #include <ffi/ffi.h>
  44 #define USE_LIBFFI
  45 #endif
  46 #endif
  47
  48 using namespace llvm;
  49
  50 static ManagedStatic<sys::Mutex> FunctionsLock;
  51
  52 typedef GenericValue (*ExFunc)(FunctionType *,
  53                                const std::vector<GenericValue> &);
  54 static ManagedStatic<std::map<const Function *, ExFunc> > ExportedFunctions;
  55 static ManagedStatic<std::map<std::string, ExFunc> > FuncNames;
  56
  57 #ifdef USE_LIBFFI
  58 typedef void (*RawFunc)();
  59 static ManagedStatic<std::map<const Function *, RawFunc> > RawFunctions;
  60 #endif
  61
  62 static Interpreter *TheInterpreter;
  63
  64 static char getTypeID(Type *Ty) {
  65   switch (Ty->getTypeID()) {
  66   case Type::VoidTyID:    return 'V';
  67   case Type::IntegerTyID:
  68     switch (cast<IntegerType>(Ty)->getBitWidth()) {
  69       case 1:  return 'o';
  70       case 8:  return 'B';
  71       case 16: return 'S';
  72       case 32: return 'I';
  73       case 64: return 'L';
  74       default: return 'N';
  75     }
  76   case Type::FloatTyID:   return 'F';
  77   case Type::DoubleTyID:  return 'D';
  78   case Type::PointerTyID: return 'P';
  79   case Type::FunctionTyID:return 'M';
  80   case Type::StructTyID:  return 'T';
  81   case Type::ArrayTyID:   return 'A';
  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   FunctionType *FT = F->getFunctionType();
  96   for (unsigned i = 0, e = FT->getNumContainedTypes(); i != e; ++i)
  97     ExtName += getTypeID(FT->getContainedType(i));
  98   ExtName += "_" + F->getName().str();
  99
 100   sys::ScopedLock Writer(*FunctionsLock);
 101   ExFunc FnPtr = (*FuncNames)[ExtName];
 102   if (!FnPtr)
 103     FnPtr = (*FuncNames)["lle_X_" + F->getName().str()];
 104   if (!FnPtr)  // Try calling a generic function... if it exists...
 105     FnPtr = (ExFunc)(intptr_t)
 106       sys::DynamicLibrary::SearchForAddressOfSymbol("lle_X_" +
 107                                                     F->getName().str());
 108   if (FnPtr)
 109     ExportedFunctions->insert(std::make_pair(F, FnPtr));  // Cache for later
 110   return FnPtr;
 111 }
 112
 113 #ifdef USE_LIBFFI
 114 static ffi_type *ffiTypeFor(Type *Ty) {
 115   switch (Ty->getTypeID()) {
 116     case Type::VoidTyID: return &ffi_type_void;
 117     case Type::IntegerTyID:
 118       switch (cast<IntegerType>(Ty)->getBitWidth()) {
 119         case 8:  return &ffi_type_sint8;
 120         case 16: return &ffi_type_sint16;
 121         case 32: return &ffi_type_sint32;
 122         case 64: return &ffi_type_sint64;
 123       }
 124     case Type::FloatTyID:   return &ffi_type_float;
 125     case Type::DoubleTyID:  return &ffi_type_double;
 126     case Type::PointerTyID: return &ffi_type_pointer;
 127     default: break;
 128   }
 129   // TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
 130   report_fatal_error("Type could not be mapped for use with libffi.");
 131   return NULL;
 132 }
 133
 134 static void *ffiValueFor(Type *Ty, const GenericValue &AV,
 135                          void *ArgDataPtr) {
 136   switch (Ty->getTypeID()) {
 137     case Type::IntegerTyID:
 138       switch (cast<IntegerType>(Ty)->getBitWidth()) {
 139         case 8: {
 140           int8_t *I8Ptr = (int8_t *) ArgDataPtr;
 141           *I8Ptr = (int8_t) AV.IntVal.getZExtValue();
 142           return ArgDataPtr;
 143         }
 144         case 16: {
 145           int16_t *I16Ptr = (int16_t *) ArgDataPtr;
 146           *I16Ptr = (int16_t) AV.IntVal.getZExtValue();
 147           return ArgDataPtr;
 148         }
 149         case 32: {
 150           int32_t *I32Ptr = (int32_t *) ArgDataPtr;
 151           *I32Ptr = (int32_t) AV.IntVal.getZExtValue();
 152           return ArgDataPtr;
 153         }
 154         case 64: {
 155           int64_t *I64Ptr = (int64_t *) ArgDataPtr;
 156           *I64Ptr = (int64_t) AV.IntVal.getZExtValue();
 157           return ArgDataPtr;
 158         }
 159       }
 160     case Type::FloatTyID: {
 161       float *FloatPtr = (float *) ArgDataPtr;
 162       *FloatPtr = AV.FloatVal;
 163       return ArgDataPtr;
 164     }
 165     case Type::DoubleTyID: {
 166       double *DoublePtr = (double *) ArgDataPtr;
 167       *DoublePtr = AV.DoubleVal;
 168       return ArgDataPtr;
 169     }
 170     case Type::PointerTyID: {
 171       void **PtrPtr = (void **) ArgDataPtr;
 172       *PtrPtr = GVTOP(AV);
 173       return ArgDataPtr;
 174     }
 175     default: break;
 176   }
 177   // TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
 178   report_fatal_error("Type value could not be mapped for use with libffi.");
 179   return NULL;
 180 }
 181
 182 static bool ffiInvoke(RawFunc Fn, Function *F,
 183                       const std::vector<GenericValue> &ArgVals,
 184                       const DataLayout *TD, GenericValue &Result) {
 185   ffi_cif cif;
 186   FunctionType *FTy = F->getFunctionType();
 187   const unsigned NumArgs = F->arg_size();
 188
 189   // TODO: We don't have type information about the remaining arguments, because
 190   // this information is never passed into ExecutionEngine::runFunction().
 191   if (ArgVals.size() > NumArgs && F->isVarArg()) {
 192     report_fatal_error("Calling external var arg function '" + F->getName()
 193                       + "' is not supported by the Interpreter.");
 194   }
 195
 196   unsigned ArgBytes = 0;
 197
 198   std::vector<ffi_type*> args(NumArgs);
 199   for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
 200        A != E; ++A) {
 201     const unsigned ArgNo = A->getArgNo();
 202     Type *ArgTy = FTy->getParamType(ArgNo);
 203     args[ArgNo] = ffiTypeFor(ArgTy);
 204     ArgBytes += TD->getTypeStoreSize(ArgTy);
 205   }
 206
 207   SmallVector<uint8_t, 128> ArgData;
 208   ArgData.resize(ArgBytes);
 209   uint8_t *ArgDataPtr = ArgData.data();
 210   SmallVector<void*, 16> values(NumArgs);
 211   for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
 212        A != E; ++A) {
 213     const unsigned ArgNo = A->getArgNo();
 214     Type *ArgTy = FTy->getParamType(ArgNo);
 215     values[ArgNo] = ffiValueFor(ArgTy, ArgVals[ArgNo], ArgDataPtr);
 216     ArgDataPtr += TD->getTypeStoreSize(ArgTy);
 217   }
 218
 219   Type *RetTy = FTy->getReturnType();
 220   ffi_type *rtype = ffiTypeFor(RetTy);
 221
 222   if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, NumArgs, rtype, &args[0]) == FFI_OK) {
 223     SmallVector<uint8_t, 128> ret;
 224     if (RetTy->getTypeID() != Type::VoidTyID)
 225       ret.resize(TD->getTypeStoreSize(RetTy));
 226     ffi_call(&cif, Fn, ret.data(), values.data());
 227     switch (RetTy->getTypeID()) {
 228       case Type::IntegerTyID:
 229         switch (cast<IntegerType>(RetTy)->getBitWidth()) {
 230           case 8:  Result.IntVal = APInt(8 , *(int8_t *) ret.data()); break;
 231           case 16: Result.IntVal = APInt(16, *(int16_t*) ret.data()); break;
 232           case 32: Result.IntVal = APInt(32, *(int32_t*) ret.data()); break;
 233           case 64: Result.IntVal = APInt(64, *(int64_t*) ret.data()); break;
 234         }
 235         break;
 236       case Type::FloatTyID:   Result.FloatVal   = *(float *) ret.data(); break;
 237       case Type::DoubleTyID:  Result.DoubleVal  = *(double*) ret.data(); break;
 238       case Type::PointerTyID: Result.PointerVal = *(void **) ret.data(); break;
 239       default: break;
 240     }
 241     return true;
 242   }
 243
 244   return false;
 245 }
 246 #endif // USE_LIBFFI
 247
 248 GenericValue Interpreter::callExternalFunction(Function *F,
 249                                      const std::vector<GenericValue> &ArgVals) {
 250   TheInterpreter = this;
 251
 252   unique_lock<sys::Mutex> Guard(*FunctionsLock);
 253
 254   // Do a lookup to see if the function is in our cache... this should just be a
 255   // deferred annotation!
 256   std::map<const Function *, ExFunc>::iterator FI = ExportedFunctions->find(F);
 257   if (ExFunc Fn = (FI == ExportedFunctions->end()) ? lookupFunction(F)
 258                                                    : FI->second) {
 259     Guard.unlock();
 260     return Fn(F->getFunctionType(), ArgVals);
 261   }
 262
 263 #ifdef USE_LIBFFI
 264   std::map<const Function *, RawFunc>::iterator RF = RawFunctions->find(F);
 265   RawFunc RawFn;
 266   if (RF == RawFunctions->end()) {
 267     RawFn = (RawFunc)(intptr_t)
 268       sys::DynamicLibrary::SearchForAddressOfSymbol(F->getName());
 269     if (!RawFn)
 270       RawFn = (RawFunc)(intptr_t)getPointerToGlobalIfAvailable(F);
 271     if (RawFn != 0)
 272       RawFunctions->insert(std::make_pair(F, RawFn));  // Cache for later
 273   } else {
 274     RawFn = RF->second;
 275   }
 276
 277   Guard.unlock();
 278
 279   GenericValue Result;
 280   if (RawFn != 0 && ffiInvoke(RawFn, F, ArgVals, getDataLayout(), Result))
 281     return Result;
 282 #endif // USE_LIBFFI
 283
 284   if (F->getName() == "__main")
 285     errs() << "Tried to execute an unknown external function: "
 286       << *F->getType() << " __main\n";
 287   else
 288     report_fatal_error("Tried to execute an unknown external function: " +
 289                        F->getName());
 290 #ifndef USE_LIBFFI
 291   errs() << "Recompiling LLVM with --enable-libffi might help.\n";
 292 #endif
 293   return GenericValue();
 294 }
 295
 296
 297 //===----------------------------------------------------------------------===//
 298 //  Functions "exported" to the running application...
 299 //
 300
 301 // void atexit(Function*)
 302 static
 303 GenericValue lle_X_atexit(FunctionType *FT,
 304                           const std::vector<GenericValue> &Args) {
 305   assert(Args.size() == 1);
 306   TheInterpreter->addAtExitHandler((Function*)GVTOP(Args[0]));
 307   GenericValue GV;
 308   GV.IntVal = 0;
 309   return GV;
 310 }
 311
 312 // void exit(int)
 313 static
 314 GenericValue lle_X_exit(FunctionType *FT,
 315                         const std::vector<GenericValue> &Args) {
 316   TheInterpreter->exitCalled(Args[0]);
 317   return GenericValue();
 318 }
 319
 320 // void abort(void)
 321 static
 322 GenericValue lle_X_abort(FunctionType *FT,
 323                          const std::vector<GenericValue> &Args) {
 324   //FIXME: should we report or raise here?
 325   //report_fatal_error("Interpreted program raised SIGABRT");
 326   raise (SIGABRT);
 327   return GenericValue();
 328 }
 329
 330 // int sprintf(char *, const char *, ...) - a very rough implementation to make
 331 // output useful.
 332 static
 333 GenericValue lle_X_sprintf(FunctionType *FT,
 334                            const std::vector<GenericValue> &Args) {
 335   char *OutputBuffer = (char *)GVTOP(Args[0]);
 336   const char *FmtStr = (const char *)GVTOP(Args[1]);
 337   unsigned ArgNo = 2;
 338
 339   // printf should return # chars printed.  This is completely incorrect, but
 340   // close enough for now.
 341   GenericValue GV;
 342   GV.IntVal = APInt(32, strlen(FmtStr));
 343   while (1) {
 344     switch (*FmtStr) {
 345     case 0: return GV;             // Null terminator...
 346     default:                       // Normal nonspecial character
 347       sprintf(OutputBuffer++, "%c", *FmtStr++);
 348       break;
 349     case '\\': {                   // Handle escape codes
 350       sprintf(OutputBuffer, "%c%c", *FmtStr, *(FmtStr+1));
 351       FmtStr += 2; OutputBuffer += 2;
 352       break;
 353     }
 354     case '%': {                    // Handle format specifiers
 355       char FmtBuf[100] = "", Buffer[1000] = "";
 356       char *FB = FmtBuf;
 357       *FB++ = *FmtStr++;
 358       char Last = *FB++ = *FmtStr++;
 359       unsigned HowLong = 0;
 360       while (Last != 'c' && Last != 'd' && Last != 'i' && Last != 'u' &&
 361              Last != 'o' && Last != 'x' && Last != 'X' && Last != 'e' &&
 362              Last != 'E' && Last != 'g' && Last != 'G' && Last != 'f' &&
 363              Last != 'p' && Last != 's' && Last != '%') {
 364         if (Last == 'l' || Last == 'L') HowLong++;  // Keep track of l's
 365         Last = *FB++ = *FmtStr++;
 366       }
 367       *FB = 0;
 368
 369       switch (Last) {
 370       case '%':
 371         memcpy(Buffer, "%", 2); break;
 372       case 'c':
 373         sprintf(Buffer, FmtBuf, uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
 374         break;
 375       case 'd': case 'i':
 376       case 'u': case 'o':
 377       case 'x': case 'X':
 378         if (HowLong >= 1) {
 379           if (HowLong == 1 &&
 380               TheInterpreter->getDataLayout()->getPointerSizeInBits() == 64 &&
 381               sizeof(long) < sizeof(int64_t)) {
 382             // Make sure we use %lld with a 64 bit argument because we might be
 383             // compiling LLI on a 32 bit compiler.
 384             unsigned Size = strlen(FmtBuf);
 385             FmtBuf[Size] = FmtBuf[Size-1];
 386             FmtBuf[Size+1] = 0;
 387             FmtBuf[Size-1] = 'l';
 388           }
 389           sprintf(Buffer, FmtBuf, Args[ArgNo++].IntVal.getZExtValue());
 390         } else
 391           sprintf(Buffer, FmtBuf,uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
 392         break;
 393       case 'e': case 'E': case 'g': case 'G': case 'f':
 394         sprintf(Buffer, FmtBuf, Args[ArgNo++].DoubleVal); break;
 395       case 'p':
 396         sprintf(Buffer, FmtBuf, (void*)GVTOP(Args[ArgNo++])); break;
 397       case 's':
 398         sprintf(Buffer, FmtBuf, (char*)GVTOP(Args[ArgNo++])); break;
 399       default:
 400         errs() << "<unknown printf code '" << *FmtStr << "'!>";
 401         ArgNo++; break;
 402       }
 403       size_t Len = strlen(Buffer);
 404       memcpy(OutputBuffer, Buffer, Len + 1);
 405       OutputBuffer += Len;
 406       }
 407       break;
 408     }
 409   }
 410   return GV;
 411 }
 412
 413 // int printf(const char *, ...) - a very rough implementation to make output
 414 // useful.
 415 static
 416 GenericValue lle_X_printf(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 static
 429 GenericValue lle_X_sscanf(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 static
 445 GenericValue lle_X_scanf(FunctionType *FT,
 446                          const std::vector<GenericValue> &args) {
 447   assert(args.size() < 10 && "Only handle up to 10 args to scanf right now!");
 448
 449   char *Args[10];
 450   for (unsigned i = 0; i < args.size(); ++i)
 451     Args[i] = (char*)GVTOP(args[i]);
 452
 453   GenericValue GV;
 454   GV.IntVal = APInt(32, scanf( Args[0], Args[1], Args[2], Args[3], Args[4],
 455                     Args[5], Args[6], Args[7], Args[8], Args[9]));
 456   return GV;
 457 }
 458
 459 // int fprintf(FILE *, const char *, ...) - a very rough implementation to make
 460 // output useful.
 461 static
 462 GenericValue lle_X_fprintf(FunctionType *FT,
 463                            const std::vector<GenericValue> &Args) {
 464   assert(Args.size() >= 2);
 465   char Buffer[10000];
 466   std::vector<GenericValue> NewArgs;
 467   NewArgs.push_back(PTOGV(Buffer));
 468   NewArgs.insert(NewArgs.end(), Args.begin()+1, Args.end());
 469   GenericValue GV = lle_X_sprintf(FT, NewArgs);
 470
 471   fputs(Buffer, (FILE *) GVTOP(Args[0]));
 472   return GV;
 473 }
 474
 475 static GenericValue lle_X_memset(FunctionType *FT,
 476                                  const std::vector<GenericValue> &Args) {
 477   int val = (int)Args[1].IntVal.getSExtValue();
 478   size_t len = (size_t)Args[2].IntVal.getZExtValue();
 479   memset((void *)GVTOP(Args[0]), val, len);
 480   // llvm.memset.* returns void, lle_X_* returns GenericValue,
 481   // so here we return GenericValue with IntVal set to zero
 482   GenericValue GV;
 483   GV.IntVal = 0;
 484   return GV;
 485 }
 486
 487 static GenericValue lle_X_memcpy(FunctionType *FT,
 488                                  const std::vector<GenericValue> &Args) {
 489   memcpy(GVTOP(Args[0]), GVTOP(Args[1]),
 490          (size_t)(Args[2].IntVal.getLimitedValue()));
 491
 492   // llvm.memcpy* returns void, lle_X_* returns GenericValue,
 493   // so here we return GenericValue with IntVal set to zero
 494   GenericValue GV;
 495   GV.IntVal = 0;
 496   return GV;
 497 }
 498
 499 void Interpreter::initializeExternalFunctions() {
 500   sys::ScopedLock Writer(*FunctionsLock);
 501   (*FuncNames)["lle_X_atexit"]       = lle_X_atexit;
 502   (*FuncNames)["lle_X_exit"]         = lle_X_exit;
 503   (*FuncNames)["lle_X_abort"]        = lle_X_abort;
 504
 505   (*FuncNames)["lle_X_printf"]       = lle_X_printf;
 506   (*FuncNames)["lle_X_sprintf"]      = lle_X_sprintf;
 507   (*FuncNames)["lle_X_sscanf"]       = lle_X_sscanf;
 508   (*FuncNames)["lle_X_scanf"]        = lle_X_scanf;
 509   (*FuncNames)["lle_X_fprintf"]      = lle_X_fprintf;
 510   (*FuncNames)["lle_X_memset"]       = lle_X_memset;
 511   (*FuncNames)["lle_X_memcpy"]       = lle_X_memcpy;
 512 }