510 lines
17 KiB
C++
510 lines
17 KiB
C++
//===-- ExternalFunctions.cpp - Implement External Functions --------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains both code to deal with invoking "external" functions, but
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// also contains code that implements "exported" external functions.
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//
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// There are currently two mechanisms for handling external functions in the
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// Interpreter. The first is to implement lle_* wrapper functions that are
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// specific to well-known library functions which manually translate the
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// arguments from GenericValues and make the call. If such a wrapper does
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// not exist, and libffi is available, then the Interpreter will attempt to
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// invoke the function using libffi, after finding its address.
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//
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//===----------------------------------------------------------------------===//
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#include "Interpreter.h"
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#include "llvm/ADT/APInt.h"
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/Config/config.h" // Detect libffi
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#include "llvm/ExecutionEngine/GenericValue.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/DerivedTypes.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/Type.h"
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#include "llvm/Support/Casting.h"
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#include "llvm/Support/DynamicLibrary.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/ManagedStatic.h"
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#include "llvm/Support/Mutex.h"
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#include "llvm/Support/raw_ostream.h"
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#include <cassert>
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#include <cmath>
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#include <csignal>
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#include <cstdint>
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#include <cstdio>
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#include <cstring>
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#include <map>
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#include <mutex>
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#include <string>
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#include <utility>
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#include <vector>
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#ifdef HAVE_FFI_CALL
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#ifdef HAVE_FFI_H
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#include <ffi.h>
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#define USE_LIBFFI
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#elif HAVE_FFI_FFI_H
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#include <ffi/ffi.h>
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#define USE_LIBFFI
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#endif
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#endif
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using namespace llvm;
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static ManagedStatic<sys::Mutex> FunctionsLock;
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typedef GenericValue (*ExFunc)(FunctionType *, ArrayRef<GenericValue>);
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static ManagedStatic<std::map<const Function *, ExFunc> > ExportedFunctions;
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static ManagedStatic<std::map<std::string, ExFunc> > FuncNames;
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#ifdef USE_LIBFFI
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typedef void (*RawFunc)();
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static ManagedStatic<std::map<const Function *, RawFunc> > RawFunctions;
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#endif
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static Interpreter *TheInterpreter;
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static char getTypeID(Type *Ty) {
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switch (Ty->getTypeID()) {
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case Type::VoidTyID: return 'V';
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case Type::IntegerTyID:
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switch (cast<IntegerType>(Ty)->getBitWidth()) {
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case 1: return 'o';
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case 8: return 'B';
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case 16: return 'S';
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case 32: return 'I';
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case 64: return 'L';
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default: return 'N';
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}
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case Type::FloatTyID: return 'F';
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case Type::DoubleTyID: return 'D';
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case Type::PointerTyID: return 'P';
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case Type::FunctionTyID:return 'M';
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case Type::StructTyID: return 'T';
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case Type::ArrayTyID: return 'A';
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default: return 'U';
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}
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}
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// Try to find address of external function given a Function object.
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// Please note, that interpreter doesn't know how to assemble a
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// real call in general case (this is JIT job), that's why it assumes,
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// that all external functions has the same (and pretty "general") signature.
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// The typical example of such functions are "lle_X_" ones.
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static ExFunc lookupFunction(const Function *F) {
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// Function not found, look it up... start by figuring out what the
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// composite function name should be.
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std::string ExtName = "lle_";
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FunctionType *FT = F->getFunctionType();
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ExtName += getTypeID(FT->getReturnType());
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for (Type *T : FT->params())
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ExtName += getTypeID(T);
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ExtName += ("_" + F->getName()).str();
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sys::ScopedLock Writer(*FunctionsLock);
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ExFunc FnPtr = (*FuncNames)[ExtName];
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if (!FnPtr)
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FnPtr = (*FuncNames)[("lle_X_" + F->getName()).str()];
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if (!FnPtr) // Try calling a generic function... if it exists...
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FnPtr = (ExFunc)(intptr_t)sys::DynamicLibrary::SearchForAddressOfSymbol(
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("lle_X_" + F->getName()).str());
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if (FnPtr)
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ExportedFunctions->insert(std::make_pair(F, FnPtr)); // Cache for later
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return FnPtr;
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}
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#ifdef USE_LIBFFI
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static ffi_type *ffiTypeFor(Type *Ty) {
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switch (Ty->getTypeID()) {
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case Type::VoidTyID: return &ffi_type_void;
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case Type::IntegerTyID:
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switch (cast<IntegerType>(Ty)->getBitWidth()) {
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case 8: return &ffi_type_sint8;
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case 16: return &ffi_type_sint16;
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case 32: return &ffi_type_sint32;
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case 64: return &ffi_type_sint64;
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}
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case Type::FloatTyID: return &ffi_type_float;
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case Type::DoubleTyID: return &ffi_type_double;
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case Type::PointerTyID: return &ffi_type_pointer;
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default: break;
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}
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// TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
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report_fatal_error("Type could not be mapped for use with libffi.");
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return NULL;
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}
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static void *ffiValueFor(Type *Ty, const GenericValue &AV,
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void *ArgDataPtr) {
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switch (Ty->getTypeID()) {
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case Type::IntegerTyID:
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switch (cast<IntegerType>(Ty)->getBitWidth()) {
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case 8: {
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int8_t *I8Ptr = (int8_t *) ArgDataPtr;
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*I8Ptr = (int8_t) AV.IntVal.getZExtValue();
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return ArgDataPtr;
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}
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case 16: {
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int16_t *I16Ptr = (int16_t *) ArgDataPtr;
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*I16Ptr = (int16_t) AV.IntVal.getZExtValue();
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return ArgDataPtr;
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}
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case 32: {
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int32_t *I32Ptr = (int32_t *) ArgDataPtr;
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*I32Ptr = (int32_t) AV.IntVal.getZExtValue();
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return ArgDataPtr;
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}
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case 64: {
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int64_t *I64Ptr = (int64_t *) ArgDataPtr;
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*I64Ptr = (int64_t) AV.IntVal.getZExtValue();
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return ArgDataPtr;
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}
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}
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case Type::FloatTyID: {
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float *FloatPtr = (float *) ArgDataPtr;
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*FloatPtr = AV.FloatVal;
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return ArgDataPtr;
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}
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case Type::DoubleTyID: {
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double *DoublePtr = (double *) ArgDataPtr;
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*DoublePtr = AV.DoubleVal;
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return ArgDataPtr;
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}
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case Type::PointerTyID: {
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void **PtrPtr = (void **) ArgDataPtr;
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*PtrPtr = GVTOP(AV);
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return ArgDataPtr;
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}
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default: break;
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}
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// TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
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report_fatal_error("Type value could not be mapped for use with libffi.");
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return NULL;
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}
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static bool ffiInvoke(RawFunc Fn, Function *F, ArrayRef<GenericValue> ArgVals,
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const DataLayout &TD, GenericValue &Result) {
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ffi_cif cif;
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FunctionType *FTy = F->getFunctionType();
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const unsigned NumArgs = F->arg_size();
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// TODO: We don't have type information about the remaining arguments, because
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// this information is never passed into ExecutionEngine::runFunction().
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if (ArgVals.size() > NumArgs && F->isVarArg()) {
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report_fatal_error("Calling external var arg function '" + F->getName()
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+ "' is not supported by the Interpreter.");
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}
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unsigned ArgBytes = 0;
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std::vector<ffi_type*> args(NumArgs);
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for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
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A != E; ++A) {
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const unsigned ArgNo = A->getArgNo();
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Type *ArgTy = FTy->getParamType(ArgNo);
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args[ArgNo] = ffiTypeFor(ArgTy);
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ArgBytes += TD.getTypeStoreSize(ArgTy);
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}
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SmallVector<uint8_t, 128> ArgData;
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ArgData.resize(ArgBytes);
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uint8_t *ArgDataPtr = ArgData.data();
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SmallVector<void*, 16> values(NumArgs);
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for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
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A != E; ++A) {
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const unsigned ArgNo = A->getArgNo();
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Type *ArgTy = FTy->getParamType(ArgNo);
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values[ArgNo] = ffiValueFor(ArgTy, ArgVals[ArgNo], ArgDataPtr);
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ArgDataPtr += TD.getTypeStoreSize(ArgTy);
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}
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Type *RetTy = FTy->getReturnType();
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ffi_type *rtype = ffiTypeFor(RetTy);
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if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, NumArgs, rtype, args.data()) ==
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FFI_OK) {
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SmallVector<uint8_t, 128> ret;
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if (RetTy->getTypeID() != Type::VoidTyID)
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ret.resize(TD.getTypeStoreSize(RetTy));
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ffi_call(&cif, Fn, ret.data(), values.data());
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switch (RetTy->getTypeID()) {
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case Type::IntegerTyID:
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switch (cast<IntegerType>(RetTy)->getBitWidth()) {
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case 8: Result.IntVal = APInt(8 , *(int8_t *) ret.data()); break;
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case 16: Result.IntVal = APInt(16, *(int16_t*) ret.data()); break;
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case 32: Result.IntVal = APInt(32, *(int32_t*) ret.data()); break;
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case 64: Result.IntVal = APInt(64, *(int64_t*) ret.data()); break;
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}
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break;
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case Type::FloatTyID: Result.FloatVal = *(float *) ret.data(); break;
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case Type::DoubleTyID: Result.DoubleVal = *(double*) ret.data(); break;
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case Type::PointerTyID: Result.PointerVal = *(void **) ret.data(); break;
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default: break;
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}
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return true;
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}
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return false;
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}
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#endif // USE_LIBFFI
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GenericValue Interpreter::callExternalFunction(Function *F,
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ArrayRef<GenericValue> ArgVals) {
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TheInterpreter = this;
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std::unique_lock<sys::Mutex> Guard(*FunctionsLock);
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// Do a lookup to see if the function is in our cache... this should just be a
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// deferred annotation!
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std::map<const Function *, ExFunc>::iterator FI = ExportedFunctions->find(F);
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if (ExFunc Fn = (FI == ExportedFunctions->end()) ? lookupFunction(F)
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: FI->second) {
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Guard.unlock();
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return Fn(F->getFunctionType(), ArgVals);
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}
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#ifdef USE_LIBFFI
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std::map<const Function *, RawFunc>::iterator RF = RawFunctions->find(F);
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RawFunc RawFn;
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if (RF == RawFunctions->end()) {
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RawFn = (RawFunc)(intptr_t)
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sys::DynamicLibrary::SearchForAddressOfSymbol(std::string(F->getName()));
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if (!RawFn)
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RawFn = (RawFunc)(intptr_t)getPointerToGlobalIfAvailable(F);
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if (RawFn != 0)
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RawFunctions->insert(std::make_pair(F, RawFn)); // Cache for later
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} else {
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RawFn = RF->second;
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}
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Guard.unlock();
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GenericValue Result;
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if (RawFn != 0 && ffiInvoke(RawFn, F, ArgVals, getDataLayout(), Result))
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return Result;
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#endif // USE_LIBFFI
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if (F->getName() == "__main")
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errs() << "Tried to execute an unknown external function: "
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<< *F->getType() << " __main\n";
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else
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report_fatal_error("Tried to execute an unknown external function: " +
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F->getName());
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#ifndef USE_LIBFFI
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errs() << "Recompiling LLVM with --enable-libffi might help.\n";
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#endif
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return GenericValue();
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}
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//===----------------------------------------------------------------------===//
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// Functions "exported" to the running application...
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//
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// void atexit(Function*)
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static GenericValue lle_X_atexit(FunctionType *FT,
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ArrayRef<GenericValue> Args) {
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assert(Args.size() == 1);
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TheInterpreter->addAtExitHandler((Function*)GVTOP(Args[0]));
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GenericValue GV;
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GV.IntVal = 0;
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return GV;
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}
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// void exit(int)
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static GenericValue lle_X_exit(FunctionType *FT, ArrayRef<GenericValue> Args) {
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TheInterpreter->exitCalled(Args[0]);
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return GenericValue();
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}
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// void abort(void)
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static GenericValue lle_X_abort(FunctionType *FT, ArrayRef<GenericValue> Args) {
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//FIXME: should we report or raise here?
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//report_fatal_error("Interpreted program raised SIGABRT");
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raise (SIGABRT);
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return GenericValue();
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}
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// int sprintf(char *, const char *, ...) - a very rough implementation to make
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// output useful.
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static GenericValue lle_X_sprintf(FunctionType *FT,
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ArrayRef<GenericValue> Args) {
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char *OutputBuffer = (char *)GVTOP(Args[0]);
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const char *FmtStr = (const char *)GVTOP(Args[1]);
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unsigned ArgNo = 2;
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// printf should return # chars printed. This is completely incorrect, but
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// close enough for now.
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GenericValue GV;
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GV.IntVal = APInt(32, strlen(FmtStr));
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while (true) {
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switch (*FmtStr) {
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case 0: return GV; // Null terminator...
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default: // Normal nonspecial character
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sprintf(OutputBuffer++, "%c", *FmtStr++);
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break;
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case '\\': { // Handle escape codes
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sprintf(OutputBuffer, "%c%c", *FmtStr, *(FmtStr+1));
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FmtStr += 2; OutputBuffer += 2;
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break;
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}
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case '%': { // Handle format specifiers
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char FmtBuf[100] = "", Buffer[1000] = "";
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char *FB = FmtBuf;
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*FB++ = *FmtStr++;
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char Last = *FB++ = *FmtStr++;
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unsigned HowLong = 0;
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while (Last != 'c' && Last != 'd' && Last != 'i' && Last != 'u' &&
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Last != 'o' && Last != 'x' && Last != 'X' && Last != 'e' &&
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Last != 'E' && Last != 'g' && Last != 'G' && Last != 'f' &&
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Last != 'p' && Last != 's' && Last != '%') {
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if (Last == 'l' || Last == 'L') HowLong++; // Keep track of l's
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Last = *FB++ = *FmtStr++;
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}
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*FB = 0;
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switch (Last) {
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case '%':
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memcpy(Buffer, "%", 2); break;
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case 'c':
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sprintf(Buffer, FmtBuf, uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
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break;
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case 'd': case 'i':
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case 'u': case 'o':
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case 'x': case 'X':
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if (HowLong >= 1) {
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if (HowLong == 1 &&
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TheInterpreter->getDataLayout().getPointerSizeInBits() == 64 &&
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sizeof(long) < sizeof(int64_t)) {
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// Make sure we use %lld with a 64 bit argument because we might be
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// compiling LLI on a 32 bit compiler.
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unsigned Size = strlen(FmtBuf);
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FmtBuf[Size] = FmtBuf[Size-1];
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FmtBuf[Size+1] = 0;
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FmtBuf[Size-1] = 'l';
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}
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sprintf(Buffer, FmtBuf, Args[ArgNo++].IntVal.getZExtValue());
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} else
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sprintf(Buffer, FmtBuf,uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
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break;
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case 'e': case 'E': case 'g': case 'G': case 'f':
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sprintf(Buffer, FmtBuf, Args[ArgNo++].DoubleVal); break;
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case 'p':
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sprintf(Buffer, FmtBuf, (void*)GVTOP(Args[ArgNo++])); break;
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case 's':
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sprintf(Buffer, FmtBuf, (char*)GVTOP(Args[ArgNo++])); break;
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default:
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errs() << "<unknown printf code '" << *FmtStr << "'!>";
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ArgNo++; break;
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}
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size_t Len = strlen(Buffer);
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memcpy(OutputBuffer, Buffer, Len + 1);
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OutputBuffer += Len;
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}
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break;
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}
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}
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return GV;
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}
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// int printf(const char *, ...) - a very rough implementation to make output
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// useful.
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static GenericValue lle_X_printf(FunctionType *FT,
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ArrayRef<GenericValue> Args) {
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char Buffer[10000];
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std::vector<GenericValue> NewArgs;
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NewArgs.push_back(PTOGV((void*)&Buffer[0]));
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llvm::append_range(NewArgs, Args);
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GenericValue GV = lle_X_sprintf(FT, NewArgs);
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outs() << Buffer;
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return GV;
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}
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// int sscanf(const char *format, ...);
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static GenericValue lle_X_sscanf(FunctionType *FT,
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ArrayRef<GenericValue> args) {
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assert(args.size() < 10 && "Only handle up to 10 args to sscanf right now!");
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char *Args[10];
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for (unsigned i = 0; i < args.size(); ++i)
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Args[i] = (char*)GVTOP(args[i]);
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GenericValue GV;
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GV.IntVal = APInt(32, sscanf(Args[0], Args[1], Args[2], Args[3], Args[4],
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Args[5], Args[6], Args[7], Args[8], Args[9]));
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return GV;
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}
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// int scanf(const char *format, ...);
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static GenericValue lle_X_scanf(FunctionType *FT, ArrayRef<GenericValue> args) {
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assert(args.size() < 10 && "Only handle up to 10 args to scanf right now!");
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char *Args[10];
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for (unsigned i = 0; i < args.size(); ++i)
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Args[i] = (char*)GVTOP(args[i]);
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GenericValue GV;
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GV.IntVal = APInt(32, scanf( Args[0], Args[1], Args[2], Args[3], Args[4],
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Args[5], Args[6], Args[7], Args[8], Args[9]));
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return GV;
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}
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// int fprintf(FILE *, const char *, ...) - a very rough implementation to make
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// output useful.
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static GenericValue lle_X_fprintf(FunctionType *FT,
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ArrayRef<GenericValue> Args) {
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assert(Args.size() >= 2);
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char Buffer[10000];
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std::vector<GenericValue> NewArgs;
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NewArgs.push_back(PTOGV(Buffer));
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NewArgs.insert(NewArgs.end(), Args.begin()+1, Args.end());
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GenericValue GV = lle_X_sprintf(FT, NewArgs);
|
|
|
|
fputs(Buffer, (FILE *) GVTOP(Args[0]));
|
|
return GV;
|
|
}
|
|
|
|
static GenericValue lle_X_memset(FunctionType *FT,
|
|
ArrayRef<GenericValue> Args) {
|
|
int val = (int)Args[1].IntVal.getSExtValue();
|
|
size_t len = (size_t)Args[2].IntVal.getZExtValue();
|
|
memset((void *)GVTOP(Args[0]), val, len);
|
|
// llvm.memset.* returns void, lle_X_* returns GenericValue,
|
|
// so here we return GenericValue with IntVal set to zero
|
|
GenericValue GV;
|
|
GV.IntVal = 0;
|
|
return GV;
|
|
}
|
|
|
|
static GenericValue lle_X_memcpy(FunctionType *FT,
|
|
ArrayRef<GenericValue> Args) {
|
|
memcpy(GVTOP(Args[0]), GVTOP(Args[1]),
|
|
(size_t)(Args[2].IntVal.getLimitedValue()));
|
|
|
|
// llvm.memcpy* returns void, lle_X_* returns GenericValue,
|
|
// so here we return GenericValue with IntVal set to zero
|
|
GenericValue GV;
|
|
GV.IntVal = 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;
|
|
(*FuncNames)["lle_X_memset"] = lle_X_memset;
|
|
(*FuncNames)["lle_X_memcpy"] = lle_X_memcpy;
|
|
}
|