path: root/lib/ExecutionEngine/Interpreter/Execution.cpp

//===-- Execution.cpp - Implement code to simulate the program ------------===//
// 
//                     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 the actual instruction interpreter.
//
//===----------------------------------------------------------------------===//

#include "Interpreter.h"
#include "llvm/Instructions.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Constants.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "Support/Statistic.h"
#include <cmath>  // For fmod
using namespace llvm;

namespace {
  Statistic<> NumDynamicInsts("lli", "Number of dynamic instructions executed");
}

namespace llvm {
  Interpreter *TheEE = 0;
}

//===----------------------------------------------------------------------===//
//                     Value Manipulation code
//===----------------------------------------------------------------------===//

// Operations used by constant expr implementations...
static GenericValue executeCastOperation(Value *Src, const Type *DestTy,
                                         ExecutionContext &SF);
static GenericValue executeAddInst(GenericValue Src1, GenericValue Src2, 
				   const Type *Ty);

GenericValue Interpreter::getOperandValue(Value *V, ExecutionContext &SF) {
  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
    switch (CE->getOpcode()) {
    case Instruction::Cast:
      return executeCastOperation(CE->getOperand(0), CE->getType(), SF);
    case Instruction::GetElementPtr:
      return TheEE->executeGEPOperation(CE->getOperand(0), gep_type_begin(CE),
					gep_type_end(CE), SF);
    case Instruction::Add:
      return executeAddInst(getOperandValue(CE->getOperand(0), SF),
                            getOperandValue(CE->getOperand(1), SF),
                            CE->getType());
    default:
      std::cerr << "Unhandled ConstantExpr: " << CE << "\n";
      abort();
      return GenericValue();
    }
  } else if (Constant *CPV = dyn_cast<Constant>(V)) {
    return TheEE->getConstantValue(CPV);
  } else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
    return PTOGV(TheEE->getPointerToGlobal(GV));
  } else {
    return SF.Values[V];
  }
}

static void SetValue(Value *V, GenericValue Val, ExecutionContext &SF) {
  SF.Values[V] = Val;
}

//===----------------------------------------------------------------------===//
//                    Annotation Wrangling code
//===----------------------------------------------------------------------===//

void Interpreter::initializeExecutionEngine() {
  TheEE = this;
}

//===----------------------------------------------------------------------===//
//                    Binary Instruction Implementations
//===----------------------------------------------------------------------===//

#define IMPLEMENT_BINARY_OPERATOR(OP, TY) \
   case Type::TY##TyID: Dest.TY##Val = Src1.TY##Val OP Src2.TY##Val; break

static GenericValue executeAddInst(GenericValue Src1, GenericValue Src2, 
				   const Type *Ty) {
  GenericValue Dest;
  switch (Ty->getPrimitiveID()) {
    IMPLEMENT_BINARY_OPERATOR(+, UByte);
    IMPLEMENT_BINARY_OPERATOR(+, SByte);
    IMPLEMENT_BINARY_OPERATOR(+, UShort);
    IMPLEMENT_BINARY_OPERATOR(+, Short);
    IMPLEMENT_BINARY_OPERATOR(+, UInt);
    IMPLEMENT_BINARY_OPERATOR(+, Int);
    IMPLEMENT_BINARY_OPERATOR(+, ULong);
    IMPLEMENT_BINARY_OPERATOR(+, Long);
    IMPLEMENT_BINARY_OPERATOR(+, Float);
    IMPLEMENT_BINARY_OPERATOR(+, Double);
  default:
    std::cout << "Unhandled type for Add instruction: " << *Ty << "\n";
    abort();
  }
  return Dest;
}

static GenericValue executeSubInst(GenericValue Src1, GenericValue Src2, 
				   const Type *Ty) {
  GenericValue Dest;
  switch (Ty->getPrimitiveID()) {
    IMPLEMENT_BINARY_OPERATOR(-, UByte);
    IMPLEMENT_BINARY_OPERATOR(-, SByte);
    IMPLEMENT_BINARY_OPERATOR(-, UShort);
    IMPLEMENT_BINARY_OPERATOR(-, Short);
    IMPLEMENT_BINARY_OPERATOR(-, UInt);
    IMPLEMENT_BINARY_OPERATOR(-, Int);
    IMPLEMENT_BINARY_OPERATOR(-, ULong);
    IMPLEMENT_BINARY_OPERATOR(-, Long);
    IMPLEMENT_BINARY_OPERATOR(-, Float);
    IMPLEMENT_BINARY_OPERATOR(-, Double);
  default:
    std::cout << "Unhandled type for Sub instruction: " << *Ty << "\n";
    abort();
  }
  return Dest;
}

static GenericValue executeMulInst(GenericValue Src1, GenericValue Src2, 
				   const Type *Ty) {
  GenericValue Dest;
  switch (Ty->getPrimitiveID()) {
    IMPLEMENT_BINARY_OPERATOR(*, UByte);
    IMPLEMENT_BINARY_OPERATOR(*, SByte);
    IMPLEMENT_BINARY_OPERATOR(*, UShort);
    IMPLEMENT_BINARY_OPERATOR