--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/ExecutionEngine/Interpreter/ExternalFunctions.cpp	Wed May 15 06:43:32 2013 +0900
@@ -0,0 +1,484 @@
+//===-- ExternalFunctions.cpp - Implement External Functions --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file 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.
+//
+//  There are currently two mechanisms for handling external functions in the
+//  Interpreter.  The first is to implement lle_* wrapper functions that are
+//  specific to well-known library functions which manually translate the
+//  arguments from GenericValues and make the call.  If such a wrapper does
+//  not exist, and libffi is available, then the Interpreter will attempt to
+//  invoke the function using libffi, after finding its address.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Interpreter.h"
+#include "llvm/Config/config.h"     // Detect libffi
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/DynamicLibrary.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/Mutex.h"
+#include <cmath>
+#include <csignal>
+#include <cstdio>
+#include <cstring>
+#include <map>
+
+#ifdef HAVE_FFI_CALL
+#ifdef HAVE_FFI_H
+#include <ffi.h>
+#define USE_LIBFFI
+#elif HAVE_FFI_FFI_H
+#include <ffi/ffi.h>
+#define USE_LIBFFI
+#endif
+#endif
+
+using namespace llvm;
+
+static ManagedStatic<sys::Mutex> FunctionsLock;
+
+typedef GenericValue (*ExFunc)(FunctionType *,
+                               const std::vector<GenericValue> &);
+static ManagedStatic<std::map<const Function *, ExFunc> > ExportedFunctions;
+static std::map<std::string, ExFunc> FuncNames;
+
+#ifdef USE_LIBFFI
+typedef void (*RawFunc)();
+static ManagedStatic<std::map<const Function *, RawFunc> > RawFunctions;
+#endif
+
+static Interpreter *TheInterpreter;
+
+static char getTypeID(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';
+  default: return 'U';
+  }
+}
+
+// Try to find address of external function given a Function object.
+// Please note, that interpreter doesn't know how to assemble a
+// real call in general case (this is JIT job), that's why it assumes,
+// that all external functions has the same (and pretty "general") signature.
+// The typical example of such functions are "lle_X_" ones.
+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_";
+  FunctionType *FT = F->getFunctionType();
+  for (unsigned i = 0, e = FT->getNumContainedTypes(); i != e; ++i)
+    ExtName += getTypeID(FT->getContainedType(i));
+  ExtName += "_" + F->getName().str();
+
+  sys::ScopedLock Writer(*FunctionsLock);
+  ExFunc FnPtr = FuncNames[ExtName];
+  if (FnPtr == 0)
+    FnPtr = FuncNames["lle_X_" + F->getName().str()];
+  if (FnPtr == 0)  // Try calling a generic function... if it exists...
+    FnPtr = (ExFunc)(intptr_t)
+      sys::DynamicLibrary::SearchForAddressOfSymbol("lle_X_" +
+                                                    F->getName().str());
+  if (FnPtr != 0)
+    ExportedFunctions->insert(std::make_pair(F, FnPtr));  // Cache for later
+  return FnPtr;
+}
+
+#ifdef USE_LIBFFI
+static ffi_type *ffiTypeFor(Type *Ty) {
+  switch (Ty->getTypeID()) {
+    case Type::VoidTyID: return &ffi_type_void;
+    case Type::IntegerTyID:
+      switch (cast<IntegerType>(Ty)->getBitWidth()) {
+        case 8:  return &ffi_type_sint8;
+        case 16: return &ffi_type_sint16;
+        case 32: return &ffi_type_sint32;
+        case 64: return &ffi_type_sint64;
+      }
+    case Type::FloatTyID:   return &ffi_type_float;
+    case Type::DoubleTyID:  return &ffi_type_double;
+    case Type::PointerTyID: return &ffi_type_pointer;
+    default: break;
+  }
+  // TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
+  report_fatal_error("Type could not be mapped for use with libffi.");
+  return NULL;
+}
+
+static void *ffiValueFor(Type *Ty, const GenericValue &AV,
+                         void *ArgDataPtr) {
+  switch (Ty->getTypeID()) {
+    case Type::IntegerTyID:
+      switch (cast<IntegerType>(Ty)->getBitWidth()) {
+        case 8: {
+          int8_t *I8Ptr = (int8_t *) ArgDataPtr;
+          *I8Ptr = (int8_t) AV.IntVal.getZExtValue();
+          return ArgDataPtr;
+        }
+        case 16: {
+          int16_t *I16Ptr = (int16_t *) ArgDataPtr;
+          *I16Ptr = (int16_t) AV.IntVal.getZExtValue();
+          return ArgDataPtr;
+        }
+        case 32: {
+          int32_t *I32Ptr = (int32_t *) ArgDataPtr;
+          *I32Ptr = (int32_t) AV.IntVal.getZExtValue();
+          return ArgDataPtr;
+        }
+        case 64: {
+          int64_t *I64Ptr = (int64_t *) ArgDataPtr;
+          *I64Ptr = (int64_t) AV.IntVal.getZExtValue();
+          return ArgDataPtr;
+        }
+      }
+    case Type::FloatTyID: {
+      float *FloatPtr = (float *) ArgDataPtr;
+      *FloatPtr = AV.FloatVal;
+      return ArgDataPtr;
+    }
+    case Type::DoubleTyID: {
+      double *DoublePtr = (double *) ArgDataPtr;
+      *DoublePtr = AV.DoubleVal;
+      return ArgDataPtr;
+    }
+    case Type::PointerTyID: {
+      void **PtrPtr = (void **) ArgDataPtr;
+      *PtrPtr = GVTOP(AV);
+      return ArgDataPtr;
+    }
+    default: break;
+  }
+  // TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
+  report_fatal_error("Type value could not be mapped for use with libffi.");
+  return NULL;
+}
+
+static bool ffiInvoke(RawFunc Fn, Function *F,
+                      const std::vector<GenericValue> &ArgVals,
+                      const DataLayout *TD, GenericValue &Result) {
+  ffi_cif cif;
+  FunctionType *FTy = F->getFunctionType();
+  const unsigned NumArgs = F->arg_size();
+
+  // TODO: We don't have type information about the remaining arguments, because
+  // this information is never passed into ExecutionEngine::runFunction().
+  if (ArgVals.size() > NumArgs && F->isVarArg()) {
+    report_fatal_error("Calling external var arg function '" + F->getName()
+                      + "' is not supported by the Interpreter.");
+  }
+
+  unsigned ArgBytes = 0;
+
+  std::vector<ffi_type*> args(NumArgs);
+  for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
+       A != E; ++A) {
+    const unsigned ArgNo = A->getArgNo();
+    Type *ArgTy = FTy->getParamType(ArgNo);
+    args[ArgNo] = ffiTypeFor(ArgTy);
+    ArgBytes += TD->getTypeStoreSize(ArgTy);
+  }
+
+  SmallVector<uint8_t, 128> ArgData;
+  ArgData.resize(ArgBytes);
+  uint8_t *ArgDataPtr = ArgData.data();
+  SmallVector<void*, 16> values(NumArgs);
+  for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
+       A != E; ++A) {
+    const unsigned ArgNo = A->getArgNo();
+    Type *ArgTy = FTy->getParamType(ArgNo);
+    values[ArgNo] = ffiValueFor(ArgTy, ArgVals[ArgNo], ArgDataPtr);
+    ArgDataPtr += TD->getTypeStoreSize(ArgTy);
+  }
+
+  Type *RetTy = FTy->getReturnType();
+  ffi_type *rtype = ffiTypeFor(RetTy);
+
+  if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, NumArgs, rtype, &args[0]) == FFI_OK) {
+    SmallVector<uint8_t, 128> ret;
+    if (RetTy->getTypeID() != Type::VoidTyID)
+      ret.resize(TD->getTypeStoreSize(RetTy));
+    ffi_call(&cif, Fn, ret.data(), values.data());
+    switch (RetTy->getTypeID()) {
+      case Type::IntegerTyID:
+        switch (cast<IntegerType>(RetTy)->getBitWidth()) {
+          case 8:  Result.IntVal = APInt(8 , *(int8_t *) ret.data()); break;
+          case 16: Result.IntVal = APInt(16, *(int16_t*) ret.data()); break;
+          case 32: Result.IntVal = APInt(32, *(int32_t*) ret.data()); break;
+          case 64: Result.IntVal = APInt(64, *(int64_t*) ret.data()); break;
+        }
+        break;
+      case Type::FloatTyID:   Result.FloatVal   = *(float *) ret.data(); break;
+      case Type::DoubleTyID:  Result.DoubleVal  = *(double*) ret.data(); break;
+      case Type::PointerTyID: Result.PointerVal = *(void **) ret.data(); break;
+      default: break;
+    }
+    return true;
+  }
+
+  return false;
+}
+#endif // USE_LIBFFI
+
+GenericValue Interpreter::callExternalFunction(Function *F,
+                                     const std::vector<GenericValue> &ArgVals) {
+  TheInterpreter = this;
+
+  FunctionsLock->acquire();
+
+  // 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 = ExportedFunctions->find(F);
+  if (ExFunc Fn = (FI == ExportedFunctions->end()) ? lookupFunction(F)
+                                                   : FI->second) {
+    FunctionsLock->release();
+    return Fn(F->getFunctionType(), ArgVals);
+  }
+
+#ifdef USE_LIBFFI
+  std::map<const Function *, RawFunc>::iterator RF = RawFunctions->find(F);
+  RawFunc RawFn;
+  if (RF == RawFunctions->end()) {
+    RawFn = (RawFunc)(intptr_t)
+      sys::DynamicLibrary::SearchForAddressOfSymbol(F->getName());
+    if (!RawFn)
+      RawFn = (RawFunc)(intptr_t)getPointerToGlobalIfAvailable(F);
+    if (RawFn != 0)
+      RawFunctions->insert(std::make_pair(F, RawFn));  // Cache for later
+  } else {
+    RawFn = RF->second;
+  }
+
+  FunctionsLock->release();
+
+  GenericValue Result;
+  if (RawFn != 0 && ffiInvoke(RawFn, F, ArgVals, getDataLayout(), Result))
+    return Result;
+#endif // USE_LIBFFI
+
+  if (F->getName() == "__main")
+    errs() << "Tried to execute an unknown external function: "
+      << *F->getType() << " __main\n";
+  else
+    report_fatal_error("Tried to execute an unknown external function: " +
+                       F->getName());
+#ifndef USE_LIBFFI
+  errs() << "Recompiling LLVM with --enable-libffi might help.\n";
+#endif
+  return GenericValue();
+}
+
+
+//===----------------------------------------------------------------------===//
+//  Functions "exported" to the running application...
+//
+
+// void atexit(Function*)
+static
+GenericValue lle_X_atexit(FunctionType *FT,
+                          const std::vector<GenericValue> &Args) {
+  assert(Args.size() == 1);
+  TheInterpreter->addAtExitHandler((Function*)GVTOP(Args[0]));
+  GenericValue GV;
+  GV.IntVal = 0;
+  return GV;
+}
+
+// void exit(int)
+static
+GenericValue lle_X_exit(FunctionType *FT,
+                        const std::vector<GenericValue> &Args) {
+  TheInterpreter->exitCalled(Args[0]);
+  return GenericValue();
+}
+
+// void abort(void)
+static
+GenericValue lle_X_abort(FunctionType *FT,
+                         const std::vector<GenericValue> &Args) {
+  //FIXME: should we report or raise here?
+  //report_fatal_error("Interpreted program raised SIGABRT");
+  raise (SIGABRT);
+  return GenericValue();
+}
+
+// int sprintf(char *, const char *, ...) - a very rough implementation to make
+// output useful.
+static
+GenericValue lle_X_sprintf(FunctionType *FT,
+                           const std::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 '%':
+        memcpy(Buffer, "%", 2); 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->getDataLayout()->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:
+        errs() << "<unknown printf code '" << *FmtStr << "'!>";
+        ArgNo++; break;
+      }
+      size_t Len = strlen(Buffer);
+      memcpy(OutputBuffer, Buffer, Len + 1);
+      OutputBuffer += Len;
+      }
+      break;
+    }
+  }
+}
+
+// int printf(const char *, ...) - a very rough implementation to make output
+// useful.
+static
+GenericValue lle_X_printf(FunctionType *FT,
+                          const std::vector<GenericValue> &Args) {
+  char Buffer[10000];
+  std::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);
+  outs() << Buffer;
+  return GV;
+}
+
+// int sscanf(const char *format, ...);
+static
+GenericValue lle_X_sscanf(FunctionType *FT,
+                          const std::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]));
+  return GV;
+}
+
+// int scanf(const char *format, ...);
+static
+GenericValue lle_X_scanf(FunctionType *FT,
+                         const std::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]));
+  return GV;
+}
+
+// int fprintf(FILE *, const char *, ...) - a very rough implementation to make
+// output useful.
+static
+GenericValue lle_X_fprintf(FunctionType *FT,
+                           const std::vector<GenericValue> &Args) {
+  assert(Args.size() >= 2);
+  char Buffer[10000];
+  std::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, (FILE *) GVTOP(Args[0]));
+  return GV;
+}
+
+void Interpreter::initializeExternalFunctions() {
+  sys::ScopedLock Writer(*FunctionsLock);
+  FuncNames["lle_X_atexit"]       = lle_X_atexit;
+  FuncNames["lle_X_exit"]         = lle_X_exit;
+  FuncNames["lle_X_abort"]        = lle_X_abort;
+
+  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_X_fprintf"]      = lle_X_fprintf;
+}