It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ExecutionEngine/Interpreter/ExternalFunctions.cpp b/lib/ExecutionEngine/Interpreter/ExternalFunctions.cpp
new file mode 100644
index 0000000..14dcdf9
--- /dev/null
+++ b/lib/ExecutionEngine/Interpreter/ExternalFunctions.cpp
@@ -0,0 +1,757 @@
+//===-- ExternalFunctions.cpp - Implement External Functions --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file contains both code to deal with invoking "external" functions, but
+//  also contains code that implements "exported" external functions.
+//
+//  External functions in the interpreter are implemented by
+//  using the system's dynamic loader to look up the address of the function
+//  we want to invoke.  If a function is found, then one of the
+//  many lle_* wrapper functions in this file will translate its arguments from
+//  GenericValues to the types the function is actually expecting, before the
+//  function is called.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Interpreter.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Module.h"
+#include "llvm/Support/Streams.h"
+#include "llvm/System/DynamicLibrary.h"
+#include "llvm/Target/TargetData.h"
+#include <csignal>
+#include <map>
+#include <cmath>
+using std::vector;
+
+using namespace llvm;
+
+typedef GenericValue (*ExFunc)(FunctionType *, const vector<GenericValue> &);
+static std::map<const Function *, ExFunc> Functions;
+static std::map<std::string, ExFunc> FuncNames;
+
+static Interpreter *TheInterpreter;
+
+static char getTypeID(const Type *Ty) {
+  switch (Ty->getTypeID()) {
+  case Type::VoidTyID:    return 'V';
+  case Type::IntegerTyID:
+    switch (cast<IntegerType>(Ty)->getBitWidth()) {
+      case 1:  return 'o';
+      case 8:  return 'B';
+      case 16: return 'S';
+      case 32: return 'I';
+      case 64: return 'L';
+      default: return 'N';
+    }
+  case Type::FloatTyID:   return 'F';
+  case Type::DoubleTyID:  return 'D';
+  case Type::PointerTyID: return 'P';
+  case Type::FunctionTyID:return 'M';
+  case Type::StructTyID:  return 'T';
+  case Type::ArrayTyID:   return 'A';
+  case Type::OpaqueTyID:  return 'O';
+  default: return 'U';
+  }
+}
+
+static ExFunc lookupFunction(const Function *F) {
+  // Function not found, look it up... start by figuring out what the
+  // composite function name should be.
+  std::string ExtName = "lle_";
+  const FunctionType *FT = F->getFunctionType();
+  for (unsigned i = 0, e = FT->getNumContainedTypes(); i != e; ++i)
+    ExtName += getTypeID(FT->getContainedType(i));
+  ExtName += "_" + F->getName();
+
+  ExFunc FnPtr = FuncNames[ExtName];
+  if (FnPtr == 0)
+    FnPtr = FuncNames["lle_X_"+F->getName()];
+  if (FnPtr == 0)  // Try calling a generic function... if it exists...
+    FnPtr = (ExFunc)(intptr_t)sys::DynamicLibrary::SearchForAddressOfSymbol(
+            ("lle_X_"+F->getName()).c_str());
+  if (FnPtr == 0)
+    FnPtr = (ExFunc)(intptr_t)
+      sys::DynamicLibrary::SearchForAddressOfSymbol(F->getName());
+  if (FnPtr != 0)
+    Functions.insert(std::make_pair(F, FnPtr));  // Cache for later
+  return FnPtr;
+}
+
+GenericValue Interpreter::callExternalFunction(Function *F,
+                                     const std::vector<GenericValue> &ArgVals) {
+  TheInterpreter = this;
+
+  // Do a lookup to see if the function is in our cache... this should just be a
+  // deferred annotation!
+  std::map<const Function *, ExFunc>::iterator FI = Functions.find(F);
+  ExFunc Fn = (FI == Functions.end()) ? lookupFunction(F) : FI->second;
+  if (Fn == 0) {
+    cerr << "Tried to execute an unknown external function: "
+         << F->getType()->getDescription() << " " << F->getName() << "\n";
+    if (F->getName() == "__main")
+      return GenericValue();
+    abort();
+  }
+
+  // TODO: FIXME when types are not const!
+  GenericValue Result = Fn(const_cast<FunctionType*>(F->getFunctionType()),
+                           ArgVals);
+  return Result;
+}
+
+
+//===----------------------------------------------------------------------===//
+//  Functions "exported" to the running application...
+//
+extern "C" {  // Don't add C++ manglings to llvm mangling :)
+
+// void putchar(ubyte)
+GenericValue lle_X_putchar(FunctionType *FT, const vector<GenericValue> &Args){
+  cout << ((char)Args[0].IntVal.getZExtValue()) << std::flush;
+  return Args[0];
+}
+
+// void _IO_putc(int c, FILE* fp)
+GenericValue lle_X__IO_putc(FunctionType *FT, const vector<GenericValue> &Args){
+#ifdef __linux__
+  _IO_putc((char)Args[0].IntVal.getZExtValue(), (FILE*) Args[1].PointerVal);
+#else
+  assert(0 && "Can't call _IO_putc on this platform");
+#endif
+  return Args[0];
+}
+
+// void atexit(Function*)
+GenericValue lle_X_atexit(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  TheInterpreter->addAtExitHandler((Function*)GVTOP(Args[0]));
+  GenericValue GV;
+  GV.IntVal = 0;
+  return GV;
+}
+
+// void exit(int)
+GenericValue lle_X_exit(FunctionType *FT, const vector<GenericValue> &Args) {
+  TheInterpreter->exitCalled(Args[0]);
+  return GenericValue();
+}
+
+// void abort(void)
+GenericValue lle_X_abort(FunctionType *FT, const vector<GenericValue> &Args) {
+  raise (SIGABRT);
+  return GenericValue();
+}
+
+// void *malloc(uint)
+GenericValue lle_X_malloc(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1 && "Malloc expects one argument!");
+  assert(isa<PointerType>(FT->getReturnType()) && "malloc must return pointer");
+  return PTOGV(malloc(Args[0].IntVal.getZExtValue()));
+}
+
+// void *calloc(uint, uint)
+GenericValue lle_X_calloc(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 2 && "calloc expects two arguments!");
+  assert(isa<PointerType>(FT->getReturnType()) && "calloc must return pointer");
+  return PTOGV(calloc(Args[0].IntVal.getZExtValue(), 
+                      Args[1].IntVal.getZExtValue()));
+}
+
+// void *calloc(uint, uint)
+GenericValue lle_X_realloc(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 2 && "calloc expects two arguments!");
+  assert(isa<PointerType>(FT->getReturnType()) &&"realloc must return pointer");
+  return PTOGV(realloc(GVTOP(Args[0]), Args[1].IntVal.getZExtValue()));
+}
+
+// void free(void *)
+GenericValue lle_X_free(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  free(GVTOP(Args[0]));
+  return GenericValue();
+}
+
+// int atoi(char *)
+GenericValue lle_X_atoi(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  GenericValue GV;
+  GV.IntVal = APInt(32, atoi((char*)GVTOP(Args[0])));
+  return GV;
+}
+
+// double pow(double, double)
+GenericValue lle_X_pow(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 2);
+  GenericValue GV;
+  GV.DoubleVal = pow(Args[0].DoubleVal, Args[1].DoubleVal);
+  return GV;
+}
+
+// double exp(double)
+GenericValue lle_X_exp(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  GenericValue GV;
+  GV.DoubleVal = exp(Args[0].DoubleVal);
+  return GV;
+}
+
+// double sqrt(double)
+GenericValue lle_X_sqrt(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  GenericValue GV;
+  GV.DoubleVal = sqrt(Args[0].DoubleVal);
+  return GV;
+}
+
+// double log(double)
+GenericValue lle_X_log(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  GenericValue GV;
+  GV.DoubleVal = log(Args[0].DoubleVal);
+  return GV;
+}
+
+// double floor(double)
+GenericValue lle_X_floor(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  GenericValue GV;
+  GV.DoubleVal = floor(Args[0].DoubleVal);
+  return GV;
+}
+
+#ifdef HAVE_RAND48
+
+// double drand48()
+GenericValue lle_X_drand48(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 0);
+  GenericValue GV;
+  GV.DoubleVal = drand48();
+  return GV;
+}
+
+// long lrand48()
+GenericValue lle_X_lrand48(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 0);
+  GenericValue GV;
+  GV.Int32Val = lrand48();
+  return GV;
+}
+
+// void srand48(long)
+GenericValue lle_X_srand48(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  srand48(Args[0].Int32Val);
+  return GenericValue();
+}
+
+#endif
+
+// int rand()
+GenericValue lle_X_rand(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 0);
+  GenericValue GV;
+  GV.IntVal = APInt(32, rand());
+  return GV;
+}
+
+// void srand(uint)
+GenericValue lle_X_srand(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  srand(Args[0].IntVal.getZExtValue());
+  return GenericValue();
+}
+
+// int puts(const char*)
+GenericValue lle_X_puts(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  GenericValue GV;
+  GV.IntVal = APInt(32, puts((char*)GVTOP(Args[0])));
+  return GV;
+}
+
+// int sprintf(sbyte *, sbyte *, ...) - a very rough implementation to make
+// output useful.
+GenericValue lle_X_sprintf(FunctionType *FT, const vector<GenericValue> &Args) {
+  char *OutputBuffer = (char *)GVTOP(Args[0]);
+  const char *FmtStr = (const char *)GVTOP(Args[1]);
+  unsigned ArgNo = 2;
+
+  // printf should return # chars printed.  This is completely incorrect, but
+  // close enough for now.
+  GenericValue GV; 
+  GV.IntVal = APInt(32, strlen(FmtStr));
+  while (1) {
+    switch (*FmtStr) {
+    case 0: return GV;             // Null terminator...
+    default:                       // Normal nonspecial character
+      sprintf(OutputBuffer++, "%c", *FmtStr++);
+      break;
+    case '\\': {                   // Handle escape codes
+      sprintf(OutputBuffer, "%c%c", *FmtStr, *(FmtStr+1));
+      FmtStr += 2; OutputBuffer += 2;
+      break;
+    }
+    case '%': {                    // Handle format specifiers
+      char FmtBuf[100] = "", Buffer[1000] = "";
+      char *FB = FmtBuf;
+      *FB++ = *FmtStr++;
+      char Last = *FB++ = *FmtStr++;
+      unsigned HowLong = 0;
+      while (Last != 'c' && Last != 'd' && Last != 'i' && Last != 'u' &&
+             Last != 'o' && Last != 'x' && Last != 'X' && Last != 'e' &&
+             Last != 'E' && Last != 'g' && Last != 'G' && Last != 'f' &&
+             Last != 'p' && Last != 's' && Last != '%') {
+        if (Last == 'l' || Last == 'L') HowLong++;  // Keep track of l's
+        Last = *FB++ = *FmtStr++;
+      }
+      *FB = 0;
+
+      switch (Last) {
+      case '%':
+        sprintf(Buffer, FmtBuf); break;
+      case 'c':
+        sprintf(Buffer, FmtBuf, uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
+        break;
+      case 'd': case 'i':
+      case 'u': case 'o':
+      case 'x': case 'X':
+        if (HowLong >= 1) {
+          if (HowLong == 1 &&
+              TheInterpreter->getTargetData()->getPointerSizeInBits() == 64 &&
+              sizeof(long) < sizeof(int64_t)) {
+            // Make sure we use %lld with a 64 bit argument because we might be
+            // compiling LLI on a 32 bit compiler.
+            unsigned Size = strlen(FmtBuf);
+            FmtBuf[Size] = FmtBuf[Size-1];
+            FmtBuf[Size+1] = 0;
+            FmtBuf[Size-1] = 'l';
+          }
+          sprintf(Buffer, FmtBuf, Args[ArgNo++].IntVal.getZExtValue());
+        } else
+          sprintf(Buffer, FmtBuf,uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
+        break;
+      case 'e': case 'E': case 'g': case 'G': case 'f':
+        sprintf(Buffer, FmtBuf, Args[ArgNo++].DoubleVal); break;
+      case 'p':
+        sprintf(Buffer, FmtBuf, (void*)GVTOP(Args[ArgNo++])); break;
+      case 's':
+        sprintf(Buffer, FmtBuf, (char*)GVTOP(Args[ArgNo++])); break;
+      default:  cerr << "<unknown printf code '" << *FmtStr << "'!>";
+        ArgNo++; break;
+      }
+      strcpy(OutputBuffer, Buffer);
+      OutputBuffer += strlen(Buffer);
+      }
+      break;
+    }
+  }
+  return GV;
+}
+
+// int printf(sbyte *, ...) - a very rough implementation to make output useful.
+GenericValue lle_X_printf(FunctionType *FT, const vector<GenericValue> &Args) {
+  char Buffer[10000];
+  vector<GenericValue> NewArgs;
+  NewArgs.push_back(PTOGV((void*)&Buffer[0]));
+  NewArgs.insert(NewArgs.end(), Args.begin(), Args.end());
+  GenericValue GV = lle_X_sprintf(FT, NewArgs);
+  cout << Buffer;
+  return GV;
+}
+
+static void ByteswapSCANFResults(const char *Fmt, void *Arg0, void *Arg1,
+                                 void *Arg2, void *Arg3, void *Arg4, void *Arg5,
+                                 void *Arg6, void *Arg7, void *Arg8) {
+  void *Args[] = { Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8, 0 };
+
+  // Loop over the format string, munging read values as appropriate (performs
+  // byteswaps as necessary).
+  unsigned ArgNo = 0;
+  while (*Fmt) {
+    if (*Fmt++ == '%') {
+      // Read any flag characters that may be present...
+      bool Suppress = false;
+      bool Half = false;
+      bool Long = false;
+      bool LongLong = false;  // long long or long double
+
+      while (1) {
+        switch (*Fmt++) {
+        case '*': Suppress = true; break;
+        case 'a': /*Allocate = true;*/ break;  // We don't need to track this
+        case 'h': Half = true; break;
+        case 'l': Long = true; break;
+        case 'q':
+        case 'L': LongLong = true; break;
+        default:
+          if (Fmt[-1] > '9' || Fmt[-1] < '0')   // Ignore field width specs
+            goto Out;
+        }
+      }
+    Out:
+
+      // Read the conversion character
+      if (!Suppress && Fmt[-1] != '%') { // Nothing to do?
+        unsigned Size = 0;
+        const Type *Ty = 0;
+
+        switch (Fmt[-1]) {
+        case 'i': case 'o': case 'u': case 'x': case 'X': case 'n': case 'p':
+        case 'd':
+          if (Long || LongLong) {
+            Size = 8; Ty = Type::Int64Ty;
+          } else if (Half) {
+            Size = 4; Ty = Type::Int16Ty;
+          } else {
+            Size = 4; Ty = Type::Int32Ty;
+          }
+          break;
+
+        case 'e': case 'g': case 'E':
+        case 'f':
+          if (Long || LongLong) {
+            Size = 8; Ty = Type::DoubleTy;
+          } else {
+            Size = 4; Ty = Type::FloatTy;
+          }
+          break;
+
+        case 's': case 'c': case '[':  // No byteswap needed
+          Size = 1;
+          Ty = Type::Int8Ty;
+          break;
+
+        default: break;
+        }
+
+        if (Size) {
+          GenericValue GV;
+          void *Arg = Args[ArgNo++];
+          memcpy(&GV, Arg, Size);
+          TheInterpreter->StoreValueToMemory(GV, (GenericValue*)Arg, Ty);
+        }
+      }
+    }
+  }
+}
+
+// int sscanf(const char *format, ...);
+GenericValue lle_X_sscanf(FunctionType *FT, const vector<GenericValue> &args) {
+  assert(args.size() < 10 && "Only handle up to 10 args to sscanf right now!");
+
+  char *Args[10];
+  for (unsigned i = 0; i < args.size(); ++i)
+    Args[i] = (char*)GVTOP(args[i]);
+
+  GenericValue GV;
+  GV.IntVal = APInt(32, sscanf(Args[0], Args[1], Args[2], Args[3], Args[4],
+                        Args[5], Args[6], Args[7], Args[8], Args[9]));
+  ByteswapSCANFResults(Args[1], Args[2], Args[3], Args[4],
+                       Args[5], Args[6], Args[7], Args[8], Args[9], 0);
+  return GV;
+}
+
+// int scanf(const char *format, ...);
+GenericValue lle_X_scanf(FunctionType *FT, const vector<GenericValue> &args) {
+  assert(args.size() < 10 && "Only handle up to 10 args to scanf right now!");
+
+  char *Args[10];
+  for (unsigned i = 0; i < args.size(); ++i)
+    Args[i] = (char*)GVTOP(args[i]);
+
+  GenericValue GV;
+  GV.IntVal = APInt(32, scanf( Args[0], Args[1], Args[2], Args[3], Args[4],
+                        Args[5], Args[6], Args[7], Args[8], Args[9]));
+  ByteswapSCANFResults(Args[0], Args[1], Args[2], Args[3], Args[4],
+                       Args[5], Args[6], Args[7], Args[8], Args[9]);
+  return GV;
+}
+
+
+// int clock(void) - Profiling implementation
+GenericValue lle_i_clock(FunctionType *FT, const vector<GenericValue> &Args) {
+  extern unsigned int clock(void);
+  GenericValue GV; 
+  GV.IntVal = APInt(32, clock());
+  return GV;
+}
+
+
+//===----------------------------------------------------------------------===//
+// String Functions...
+//===----------------------------------------------------------------------===//
+
+// int strcmp(const char *S1, const char *S2);
+GenericValue lle_X_strcmp(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 2);
+  GenericValue Ret;
+  Ret.IntVal = APInt(32, strcmp((char*)GVTOP(Args[0]), (char*)GVTOP(Args[1])));
+  return Ret;
+}
+
+// char *strcat(char *Dest, const char *src);
+GenericValue lle_X_strcat(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 2);
+  assert(isa<PointerType>(FT->getReturnType()) &&"strcat must return pointer");
+  return PTOGV(strcat((char*)GVTOP(Args[0]), (char*)GVTOP(Args[1])));
+}
+
+// char *strcpy(char *Dest, const char *src);
+GenericValue lle_X_strcpy(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 2);
+  assert(isa<PointerType>(FT->getReturnType()) &&"strcpy must return pointer");
+  return PTOGV(strcpy((char*)GVTOP(Args[0]), (char*)GVTOP(Args[1])));
+}
+
+static GenericValue size_t_to_GV (size_t n) {
+  GenericValue Ret;
+  if (sizeof (size_t) == sizeof (uint64_t)) {
+    Ret.IntVal = APInt(64, n);
+  } else {
+    assert (sizeof (size_t) == sizeof (unsigned int));
+    Ret.IntVal = APInt(32, n);
+  }
+  return Ret;
+}
+
+static size_t GV_to_size_t (GenericValue GV) {
+  size_t count;
+  if (sizeof (size_t) == sizeof (uint64_t)) {
+    count = (size_t)GV.IntVal.getZExtValue();
+  } else {
+    assert (sizeof (size_t) == sizeof (unsigned int));
+    count = (size_t)GV.IntVal.getZExtValue();
+  }
+  return count;
+}
+
+// size_t strlen(const char *src);
+GenericValue lle_X_strlen(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  size_t strlenResult = strlen ((char *) GVTOP (Args[0]));
+  return size_t_to_GV (strlenResult);
+}
+
+// char *strdup(const char *src);
+GenericValue lle_X_strdup(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  assert(isa<PointerType>(FT->getReturnType()) && "strdup must return pointer");
+  return PTOGV(strdup((char*)GVTOP(Args[0])));
+}
+
+// char *__strdup(const char *src);
+GenericValue lle_X___strdup(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  assert(isa<PointerType>(FT->getReturnType()) &&"_strdup must return pointer");
+  return PTOGV(strdup((char*)GVTOP(Args[0])));
+}
+
+// void *memset(void *S, int C, size_t N)
+GenericValue lle_X_memset(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 3);
+  size_t count = GV_to_size_t (Args[2]);
+  assert(isa<PointerType>(FT->getReturnType()) && "memset must return pointer");
+  return PTOGV(memset(GVTOP(Args[0]), uint32_t(Args[1].IntVal.getZExtValue()), 
+                      count));
+}
+
+// void *memcpy(void *Dest, void *src, size_t Size);
+GenericValue lle_X_memcpy(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 3);
+  assert(isa<PointerType>(FT->getReturnType()) && "memcpy must return pointer");
+  size_t count = GV_to_size_t (Args[2]);
+  return PTOGV(memcpy((char*)GVTOP(Args[0]), (char*)GVTOP(Args[1]), count));
+}
+
+//===----------------------------------------------------------------------===//
+// IO Functions...
+//===----------------------------------------------------------------------===//
+
+// getFILE - Turn a pointer in the host address space into a legit pointer in
+// the interpreter address space.  This is an identity transformation.
+#define getFILE(ptr) ((FILE*)ptr)
+
+// FILE *fopen(const char *filename, const char *mode);
+GenericValue lle_X_fopen(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 2);
+  assert(isa<PointerType>(FT->getReturnType()) && "fopen must return pointer");
+  return PTOGV(fopen((const char *)GVTOP(Args[0]),
+                     (const char *)GVTOP(Args[1])));
+}
+
+// int fclose(FILE *F);
+GenericValue lle_X_fclose(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  GenericValue GV;
+  GV.IntVal = APInt(32, fclose(getFILE(GVTOP(Args[0]))));
+  return GV;
+}
+
+// int feof(FILE *stream);
+GenericValue lle_X_feof(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  GenericValue GV;
+
+  GV.IntVal = APInt(32, feof(getFILE(GVTOP(Args[0]))));
+  return GV;
+}
+
+// size_t fread(void *ptr, size_t size, size_t nitems, FILE *stream);
+GenericValue lle_X_fread(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 4);
+  size_t result;
+
+  result = fread((void*)GVTOP(Args[0]), GV_to_size_t (Args[1]),
+                 GV_to_size_t (Args[2]), getFILE(GVTOP(Args[3])));
+  return size_t_to_GV (result);
+}
+
+// size_t fwrite(const void *ptr, size_t size, size_t nitems, FILE *stream);
+GenericValue lle_X_fwrite(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 4);
+  size_t result;
+
+  result = fwrite((void*)GVTOP(Args[0]), GV_to_size_t (Args[1]),
+                  GV_to_size_t (Args[2]), getFILE(GVTOP(Args[3])));
+  return size_t_to_GV (result);
+}
+
+// char *fgets(char *s, int n, FILE *stream);
+GenericValue lle_X_fgets(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 3);
+  return GVTOP(fgets((char*)GVTOP(Args[0]), Args[1].IntVal.getZExtValue(),
+                     getFILE(GVTOP(Args[2]))));
+}
+
+// FILE *freopen(const char *path, const char *mode, FILE *stream);
+GenericValue lle_X_freopen(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 3);
+  assert(isa<PointerType>(FT->getReturnType()) &&"freopen must return pointer");
+  return PTOGV(freopen((char*)GVTOP(Args[0]), (char*)GVTOP(Args[1]),
+                       getFILE(GVTOP(Args[2]))));
+}
+
+// int fflush(FILE *stream);
+GenericValue lle_X_fflush(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  GenericValue GV;
+  GV.IntVal = APInt(32, fflush(getFILE(GVTOP(Args[0]))));
+  return GV;
+}
+
+// int getc(FILE *stream);
+GenericValue lle_X_getc(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  GenericValue GV;
+  GV.IntVal = APInt(32, getc(getFILE(GVTOP(Args[0]))));
+  return GV;
+}
+
+// int _IO_getc(FILE *stream);
+GenericValue lle_X__IO_getc(FunctionType *F, const vector<GenericValue> &Args) {
+  return lle_X_getc(F, Args);
+}
+
+// int fputc(int C, FILE *stream);
+GenericValue lle_X_fputc(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 2);
+  GenericValue GV;
+  GV.IntVal = APInt(32, fputc(Args[0].IntVal.getZExtValue(), 
+                              getFILE(GVTOP(Args[1]))));
+  return GV;
+}
+
+// int ungetc(int C, FILE *stream);
+GenericValue lle_X_ungetc(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 2);
+  GenericValue GV;
+  GV.IntVal = APInt(32, ungetc(Args[0].IntVal.getZExtValue(), 
+                               getFILE(GVTOP(Args[1]))));
+  return GV;
+}
+
+// int ferror (FILE *stream);
+GenericValue lle_X_ferror(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  GenericValue GV;
+  GV.IntVal = APInt(32, ferror (getFILE(GVTOP(Args[0]))));
+  return GV;
+}
+
+// int fprintf(FILE *,sbyte *, ...) - a very rough implementation to make output
+// useful.
+GenericValue lle_X_fprintf(FunctionType *FT, const vector<GenericValue> &Args) {
+  assert(Args.size() >= 2);
+  char Buffer[10000];
+  vector<GenericValue> NewArgs;
+  NewArgs.push_back(PTOGV(Buffer));
+  NewArgs.insert(NewArgs.end(), Args.begin()+1, Args.end());
+  GenericValue GV = lle_X_sprintf(FT, NewArgs);
+
+  fputs(Buffer, getFILE(GVTOP(Args[0])));
+  return GV;
+}
+
+} // End extern "C"
+
+
+void Interpreter::initializeExternalFunctions() {
+  FuncNames["lle_X_putchar"]      = lle_X_putchar;
+  FuncNames["lle_X__IO_putc"]     = lle_X__IO_putc;
+  FuncNames["lle_X_exit"]         = lle_X_exit;
+  FuncNames["lle_X_abort"]        = lle_X_abort;
+  FuncNames["lle_X_malloc"]       = lle_X_malloc;
+  FuncNames["lle_X_calloc"]       = lle_X_calloc;
+  FuncNames["lle_X_realloc"]      = lle_X_realloc;
+  FuncNames["lle_X_free"]         = lle_X_free;
+  FuncNames["lle_X_atoi"]         = lle_X_atoi;
+  FuncNames["lle_X_pow"]          = lle_X_pow;
+  FuncNames["lle_X_exp"]          = lle_X_exp;
+  FuncNames["lle_X_log"]          = lle_X_log;
+  FuncNames["lle_X_floor"]        = lle_X_floor;
+  FuncNames["lle_X_srand"]        = lle_X_srand;
+  FuncNames["lle_X_rand"]         = lle_X_rand;
+#ifdef HAVE_RAND48
+  FuncNames["lle_X_drand48"]      = lle_X_drand48;
+  FuncNames["lle_X_srand48"]      = lle_X_srand48;
+  FuncNames["lle_X_lrand48"]      = lle_X_lrand48;
+#endif
+  FuncNames["lle_X_sqrt"]         = lle_X_sqrt;
+  FuncNames["lle_X_puts"]         = lle_X_puts;
+  FuncNames["lle_X_printf"]       = lle_X_printf;
+  FuncNames["lle_X_sprintf"]      = lle_X_sprintf;
+  FuncNames["lle_X_sscanf"]       = lle_X_sscanf;
+  FuncNames["lle_X_scanf"]        = lle_X_scanf;
+  FuncNames["lle_i_clock"]        = lle_i_clock;
+
+  FuncNames["lle_X_strcmp"]       = lle_X_strcmp;
+  FuncNames["lle_X_strcat"]       = lle_X_strcat;
+  FuncNames["lle_X_strcpy"]       = lle_X_strcpy;
+  FuncNames["lle_X_strlen"]       = lle_X_strlen;
+  FuncNames["lle_X___strdup"]     = lle_X___strdup;
+  FuncNames["lle_X_memset"]       = lle_X_memset;
+  FuncNames["lle_X_memcpy"]       = lle_X_memcpy;
+
+  FuncNames["lle_X_fopen"]        = lle_X_fopen;
+  FuncNames["lle_X_fclose"]       = lle_X_fclose;
+  FuncNames["lle_X_feof"]         = lle_X_feof;
+  FuncNames["lle_X_fread"]        = lle_X_fread;
+  FuncNames["lle_X_fwrite"]       = lle_X_fwrite;
+  FuncNames["lle_X_fgets"]        = lle_X_fgets;
+  FuncNames["lle_X_fflush"]       = lle_X_fflush;
+  FuncNames["lle_X_fgetc"]        = lle_X_getc;
+  FuncNames["lle_X_getc"]         = lle_X_getc;
+  FuncNames["lle_X__IO_getc"]     = lle_X__IO_getc;
+  FuncNames["lle_X_fputc"]        = lle_X_fputc;
+  FuncNames["lle_X_ungetc"]       = lle_X_ungetc;
+  FuncNames["lle_X_fprintf"]      = lle_X_fprintf;
+  FuncNames["lle_X_freopen"]      = lle_X_freopen;
+}
+