C++ ExprAST::Codegen方法代码示例

Value *BinaryExprAST::Codegen() {
  Value *L = LHS->Codegen();
  Value *R = RHS->Codegen();
  if (L == 0 || R == 0) return 0;
  
  switch (Op) {
  case '+': return Builder.CreateAdd(L, R, "addtmp");
  case '-': return Builder.CreateSub(L, R, "subtmp");
  case '*': return Builder.CreateMul(L, R, "multmp");
  case '<':
    L = Builder.CreateFCmpULT(L, R, "cmptmp");
    // Convert bool 0/1 to double 0.0 or 1.0
    return Builder.CreateUIToFP(L, Type::getDoubleTy(getGlobalContext()),
                                "booltmp");
  default: break;
  }
  
  // If it wasn't a builtin binary operator, it must be a user defined one. Emit
  // a call to it.
  Function *F = TheModule->getFunction(std::string("binary")+Op);
  assert(F && "binary operator not found!");
  
  Value *Ops[] = { L, R };
  return Builder.CreateCall(F, Ops, Ops+2, "binop");
}

Value *BinaryExprAST::Codegen() {
    // Special case '=' because we don't want to emit the LHS as an expression.
    if (Op == '=') {
        // Assignment requires the LHS to be an identifier.
        // This assume we're building without RTTI because LLVM builds that way by
        // default.  If you build LLVM with RTTI this can be changed to a
        // dynamic_cast for automatic error checking.
        VariableExprAST *LHSE = static_cast<VariableExprAST*>(LHS);
        if (!LHSE)
            return ErrorV("destination of '=' must be a variable");
        // Codegen the RHS.
        Value *Val = RHS->Codegen();
        if (Val == 0) return 0;

        // Look up the name.
        Value *Variable = NamedValues[LHSE->getName()];
        if (Variable == 0) return ErrorV("Unknown variable name");

        Builder.CreateStore(Val, Variable);
        return Val;
    }

    Value *L = LHS->Codegen();
    Value *R = RHS->Codegen();
    if (L == 0 || R == 0) return 0;

    switch (Op) {
    case '+':
        return Builder.CreateFAdd(L, R, "addtmp");
    case '-':
        return Builder.CreateFSub(L, R, "subtmp");
    case '*':
        return Builder.CreateFMul(L, R, "multmp");
    case '/':
        return Builder.CreateFDiv(L, R, "divtmp");
    case '<':
        L = Builder.CreateFCmpULT(L, R, "cmptmp");
        // Convert bool 0/1 to double 0.0 or 1.0
        return Builder.CreateUIToFP(L, Type::getDoubleTy(TheContext), "booltmp");
    default:
        break;
    }

    // If it wasn't a builtin binary operator, it must be a user defined one. Emit
    // a call to it.
    Function *F;
    F = TheHelper->getFunction(MakeLegalFunctionName(std::string("binary")+Op));
    assert(F && "binary operator not found!");

    Value *Ops[] = { L, R };
    return Builder.CreateCall(F, Ops, "binop");
}

Value *IfExprAST::Codegen() {
  Value *CondV = Cond->Codegen();
  if (CondV == 0) return 0;
  
  // Convert condition to a bool by comparing equal to 0.0.
  CondV = Builder.CreateFCmpONE(CondV, 
                              ConstantFP::get(getGlobalContext(), APFloat(0.0)),
                                "ifcond");
  
  Function *TheFunction = Builder.GetInsertBlock()->getParent();
  
  // Create blocks for the then and else cases.  Insert the 'then' block at the
  // end of the function.
  BasicBlock *ThenBB = BasicBlock::Create(getGlobalContext(), "then", TheFunction);
  BasicBlock *ElseBB = BasicBlock::Create(getGlobalContext(), "else");
  BasicBlock *MergeBB = BasicBlock::Create(getGlobalContext(), "ifcont");
  
  Builder.CreateCondBr(CondV, ThenBB, ElseBB);
  
  // Emit then value.
  Builder.SetInsertPoint(ThenBB);
  
  Value *ThenV = Then->Codegen();
  if (ThenV == 0) return 0;
  
  Builder.CreateBr(MergeBB);
  // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
  ThenBB = Builder.GetInsertBlock();
  
  // Emit else block.
  TheFunction->getBasicBlockList().push_back(ElseBB);
  Builder.SetInsertPoint(ElseBB);
  
  Value *ElseV = Else->Codegen();
  if (ElseV == 0) return 0;
  
  Builder.CreateBr(MergeBB);
  // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
  ElseBB = Builder.GetInsertBlock();
  
  // Emit merge block.
  TheFunction->getBasicBlockList().push_back(MergeBB);
  Builder.SetInsertPoint(MergeBB);
  PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()),
                                  "iftmp");
  
  PN->addIncoming(ThenV, ThenBB);
  PN->addIncoming(ElseV, ElseBB);
  return PN;
}

Function *FunctionAST::Codegen() {
  NamedValues.clear();
  
  Function *TheFunction = Proto->Codegen();
  if (TheFunction == 0)
    return 0;
  
  // Create a new basic block to start insertion into.
  BasicBlock *BB = BasicBlock::Create(getGlobalContext(), "entry", TheFunction);
  Builder.SetInsertPoint(BB);
  
  if (Value *RetVal = Body->Codegen()) {
    // Finish off the function.
    Builder.CreateRet(RetVal);

    // Validate the generated code, checking for consistency.
    verifyFunction(*TheFunction);

    // Optimize the function.
    TheFPM->run(*TheFunction);
    
    return TheFunction;
  }
  
  // Error reading body, remove function.
  TheFunction->eraseFromParent();
  return 0;
}

Value *VarExprAST::Codegen() {
  std::vector<AllocaInst *> OldBindings;

  Function *TheFunction = Builder.GetInsertBlock()->getParent();

  for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {
    const std::string &VarName = VarNames[i].first;
    ExprAST *Init = VarNames[i].second;
    Value *InitVal;
    if (Init) {
      InitVal = Init->Codegen();
      if (InitVal == 0) return 0;
    } else {
      InitVal = ConstantFP::get(getGlobalContext(), APFloat(0.0));
    }

    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
    Builder.CreateStore(InitVal, Alloca);

    OldBindings.push_back(NamedValues[VarName]);
    NamedValues[VarName] = Alloca;
  }

  KSDbgInfo.emitLocation(this);

  Value *BodyVal = Body->Codegen();
  if (!BodyVal) return 0;

  for (unsigned i = 0,  e = VarNames.size(); i != e; ++i)
    NamedValues[VarNames[i].first] = OldBindings[i];

  return BodyVal;
}

Function *FunctionAST::Codegen() {
  NamedValues.clear();

  Function *TheFunction = Proto->Codegen();
  if (TheFunction == 0)
    return 0;

  // If this is an operator, install it.
  if (Proto->isBinaryOp())
    BinopPrecedence[Proto->getOperatorName()] = Proto->getBinaryPrecedence();

  // Create a new basic block to start insertion into.
  BasicBlock *BB = BasicBlock::Create(TheContext, "entry", TheFunction);
  Builder.SetInsertPoint(BB);

  // Add all arguments to the symbol table and create their allocas.
  Proto->CreateArgumentAllocas(TheFunction);

  if (Value *RetVal = Body->Codegen()) {
    // Finish off the function.
    Builder.CreateRet(RetVal);

    // Validate the generated code, checking for consistency.
    verifyFunction(*TheFunction);

    return TheFunction;
  }

  // Error reading body, remove function.
  TheFunction->eraseFromParent();

  if (Proto->isBinaryOp())
    BinopPrecedence.erase(Proto->getOperatorName());
  return 0;
}

//varexpr ::= 'var' identifier ('=' expression)?(',' identifier ('=' expression)?)* 'in' expression
Value* VarExprAST::Codegen(){
	Function* theFunc = Builder.GetInsertBlock()->getParent();
	std::vector<AllocaInst*> old_bindings;
	for (unsigned i = 0; i != this->vars.size(); ++i) {
		old_bindings.push_back(namedValues[vars[i].first]);
		ExprAST* init = vars[i].second;
		Value* init_val;
		if (init){
			init_val = init->Codegen();
			if (init_val == nullptr){
				return nullptr;
			}

		}
		else{
			init_val = ConstantFP::get(getGlobalContext(), APFloat(1.0));
		}
		AllocaInst* cur_alloca = CreateEntryBlockAlloca(theFunc, vars[i].first, init_val->getType());
		Builder.CreateStore(init_val, cur_alloca);
		namedValues[vars[i].first] = cur_alloca;
	}

	Value* body_val = this->body->Codegen();

	if (body_val == nullptr){
		return nullptr;
	}

	for (size_t i = 0; i < vars.size(); i++){
		namedValues[vars[i].first] = old_bindings[i];
	}
	return body_val;
}

Value *BinaryExprAST::Codegen() {
  Value *L = LHS->Codegen();
  Value *R = RHS->Codegen();
  if (L == 0 || R == 0) return 0;
  
  switch (Op) {
  case '+': return Builder.CreateFAdd(L, R, "addtmp");
  case '-': return Builder.CreateFSub(L, R, "subtmp");
  case '*': return Builder.CreateFMul(L, R, "multmp");
  case '<':
    L = Builder.CreateFCmpULT(L, R, "cmptmp");
    // Convert bool 0/1 to double 0.0 or 1.0
    return Builder.CreateUIToFP(L, Type::getDoubleTy(getGlobalContext()),
                                "booltmp");
  default: return ErrorV("invalid binary operator");
  }
}

Value *VarExprAST::Codegen() {
  std::vector<AllocaInst *> OldBindings;
  
  Function *TheFunction = Builder.GetInsertBlock()->getParent();

  // Register all variables and emit their initializer.
  for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {
    const std::string &VarName = VarNames[i].first;
    ExprAST *Init = VarNames[i].second;
    
    // Emit the initializer before adding the variable to scope, this prevents
    // the initializer from referencing the variable itself, and permits stuff
    // like this:
    //  var a = 1 in
    //    var a = a in ...   # refers to outer 'a'.
    Value *InitVal;
    if (Init) {
      InitVal = Init->Codegen();
      if (InitVal == 0) return 0;
    } else { // If not specified, use 0.0.
      InitVal = ConstantFP::get(TheContext, APFloat(0.0));
    }
    
    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
    Builder.CreateStore(InitVal, Alloca);

    // Remember the old variable binding so that we can restore the binding when
    // we unrecurse.
    OldBindings.push_back(NamedValues[VarName]);
    
    // Remember this binding.
    NamedValues[VarName] = Alloca;
  }
  
  // Codegen the body, now that all vars are in scope.
  Value *BodyVal = Body->Codegen();
  if (BodyVal == 0) return 0;
  
  // Pop all our variables from scope.
  for (unsigned i = 0, e = VarNames.size(); i != e; ++i)
    NamedValues[VarNames[i].first] = OldBindings[i];

  // Return the body computation.
  return BodyVal;
}

Value *BinaryExprAST::Codegen() {
  // Special case '=' because we don't want to emit the LHS as an expression.
  if (Op == '=') {
    // Assignment requires the LHS to be an identifier.
    VariableExprAST *LHSE = dynamic_cast<VariableExprAST*>(LHS);
    if (!LHSE)
      return ErrorV("destination of '=' must be a variable");
    // Codegen the RHS.
    Value *Val = RHS->Codegen();
    if (Val == 0) return 0;

    // Look up the name.
    Value *Variable = NamedValues[LHSE->getName()];
    if (Variable == 0) return ErrorV("Unknown variable name");

    Builder.CreateStore(Val, Variable);
    return Val;
  }
  
  
  Value *L = LHS->Codegen();
  Value *R = RHS->Codegen();
  if (L == 0 || R == 0) return 0;
  
  switch (Op) {
  case '+': return Builder.CreateAdd(L, R, "addtmp");
  case '-': return Builder.CreateSub(L, R, "subtmp");
  case '*': return Builder.CreateMul(L, R, "multmp");
  case '<':
    L = Builder.CreateFCmpULT(L, R, "cmptmp");
    // Convert bool 0/1 to double 0.0 or 1.0
    return Builder.CreateUIToFP(L, Type::getDoubleTy(getGlobalContext()),
                                "booltmp");
  default: break;
  }
  
  // If it wasn't a builtin binary operator, it must be a user defined one. Emit
  // a call to it.
  Function *F = TheModule->getFunction(std::string("binary")+Op);
  assert(F && "binary operator not found!");
  
  Value *Ops[] = { L, R };
  return Builder.CreateCall(F, Ops, Ops+2, "binop");
}

Value *UnaryExprAST::Codegen() {
  Value *OperandV = Operand->Codegen();
  if (OperandV == 0) return 0;
  
  Function *F = TheModule->getFunction(std::string("unary")+Opcode);
  if (F == 0)
    return ErrorV("Unknown unary operator");
  
  return Builder.CreateCall(F, OperandV, "unop");
}

Value *UnaryExprAST::Codegen() {
  Value *OperandV = Operand->Codegen();
  if (OperandV == 0) return 0;
#ifdef USE_MCJIT
  Function *F = TheHelper->getFunction(MakeLegalFunctionName(std::string("unary")+Opcode));
#else
  Function *F = TheModule->getFunction(std::string("unary")+Opcode);
#endif
  if (F == 0)
    return ErrorV("Unknown unary operator");
  
  return Builder.CreateCall(F, OperandV, "unop");
}

Value *ForExprAST::Codegen() {
  // Output this as:
  //   ...
  //   start = startexpr
  //   goto loop
  // loop: 
  //   variable = phi [start, loopheader], [nextvariable, loopend]
  //   ...
  //   bodyexpr
  //   ...
  // loopend:
  //   step = stepexpr
  //   nextvariable = variable + step
  //   endcond = endexpr
  //   br endcond, loop, endloop
  // outloop:
  
  // Emit the start code first, without 'variable' in scope.
  Value *StartVal = Start->Codegen();
  if (StartVal == 0) return 0;
  
  // Make the new basic block for the loop header, inserting after current
  // block.
  Function *TheFunction = Builder.GetInsertBlock()->getParent();
  BasicBlock *PreheaderBB = Builder.GetInsertBlock();
  BasicBlock *LoopBB = BasicBlock::Create(getGlobalContext(), "loop", TheFunction);
  
  // Insert an explicit fall through from the current block to the LoopBB.
  Builder.CreateBr(LoopBB);

  // Start insertion in LoopBB.
  Builder.SetInsertPoint(LoopBB);
  
  // Start the PHI node with an entry for Start.
  PHINode *Variable = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), VarName.c_str());
  Variable->addIncoming(StartVal, PreheaderBB);
  
  // Within the loop, the variable is defined equal to the PHI node.  If it
  // shadows an existing variable, we have to restore it, so save it now.
  Value *OldVal = NamedValues[VarName];
  NamedValues[VarName] = Variable;
  
  // Emit the body of the loop.  This, like any other expr, can change the
  // current BB.  Note that we ignore the value computed by the body, but don't
  // allow an error.
  if (Body->Codegen() == 0)
    return 0;
  
  // Emit the step value.
  Value *StepVal;
  if (Step) {
    StepVal = Step->Codegen();
    if (StepVal == 0) return 0;
  } else {
    // If not specified, use 1.0.
    StepVal = ConstantFP::get(getGlobalContext(), APFloat(1.0));
  }
  
  Value *NextVar = Builder.CreateAdd(Variable, StepVal, "nextvar");

  // Compute the end condition.
  Value *EndCond = End->Codegen();
  if (EndCond == 0) return EndCond;
  
  // Convert condition to a bool by comparing equal to 0.0.
  EndCond = Builder.CreateFCmpONE(EndCond, 
                              ConstantFP::get(getGlobalContext(), APFloat(0.0)),
                                  "loopcond");
  
  // Create the "after loop" block and insert it.
  BasicBlock *LoopEndBB = Builder.GetInsertBlock();
  BasicBlock *AfterBB = BasicBlock::Create(getGlobalContext(), "afterloop", TheFunction);
  
  // Insert the conditional branch into the end of LoopEndBB.
  Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
  
  // Any new code will be inserted in AfterBB.
  Builder.SetInsertPoint(AfterBB);
  
  // Add a new entry to the PHI node for the backedge.
  Variable->addIncoming(NextVar, LoopEndBB);
  
  // Restore the unshadowed variable.
  if (OldVal)
    NamedValues[VarName] = OldVal;
  else
    NamedValues.erase(VarName);

  
  // for expr always returns 0.0.
  return Constant::getNullValue(Type::getDoubleTy(getGlobalContext()));
}

Value *ForExprAST::Codegen() {
  // Output this as:
  //   var = alloca double
  //   ...
  //   start = startexpr
  //   store start -> var
  //   goto loop
  // loop: 
  //   ...
  //   bodyexpr
  //   ...
  // loopend:
  //   step = stepexpr
  //   endcond = endexpr
  //
  //   curvar = load var
  //   nextvar = curvar + step
  //   store nextvar -> var
  //   br endcond, loop, endloop
  // outloop:
  
  Function *TheFunction = Builder.GetInsertBlock()->getParent();

  // Create an alloca for the variable in the entry block.
  AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
  
  // Emit the start code first, without 'variable' in scope.
  Value *StartVal = Start->Codegen();
  if (StartVal == 0) return 0;
  
  // Store the value into the alloca.
  Builder.CreateStore(StartVal, Alloca);
  
  // Make the new basic block for the loop header, inserting after current
  // block.
  BasicBlock *LoopBB = BasicBlock::Create(TheContext, "loop", TheFunction);

  // Insert an explicit fall through from the current block to the LoopBB.
  Builder.CreateBr(LoopBB);

  // Start insertion in LoopBB.
  Builder.SetInsertPoint(LoopBB);
  
  // Within the loop, the variable is defined equal to the PHI node.  If it
  // shadows an existing variable, we have to restore it, so save it now.
  AllocaInst *OldVal = NamedValues[VarName];
  NamedValues[VarName] = Alloca;
  
  // Emit the body of the loop.  This, like any other expr, can change the
  // current BB.  Note that we ignore the value computed by the body, but don't
  // allow an error.
  if (Body->Codegen() == 0)
    return 0;
  
  // Emit the step value.
  Value *StepVal;
  if (Step) {
    StepVal = Step->Codegen();
    if (StepVal == 0) return 0;
  } else {
    // If not specified, use 1.0.
    StepVal = ConstantFP::get(TheContext, APFloat(1.0));
  }
  
  // Compute the end condition.
  Value *EndCond = End->Codegen();
  if (EndCond == 0) return EndCond;
  
  // Reload, increment, and restore the alloca.  This handles the case where
  // the body of the loop mutates the variable.
  Value *CurVar = Builder.CreateLoad(Alloca, VarName.c_str());
  Value *NextVar = Builder.CreateFAdd(CurVar, StepVal, "nextvar");
  Builder.CreateStore(NextVar, Alloca);
  
  // Convert condition to a bool by comparing equal to 0.0.
  EndCond = Builder.CreateFCmpONE(
      EndCond, ConstantFP::get(TheContext, APFloat(0.0)), "loopcond");

  // Create the "after loop" block and insert it.
  BasicBlock *AfterBB =
      BasicBlock::Create(TheContext, "afterloop", TheFunction);

  // Insert the conditional branch into the end of LoopEndBB.
  Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
  
  // Any new code will be inserted in AfterBB.
  Builder.SetInsertPoint(AfterBB);
  
  // Restore the unshadowed variable.
  if (OldVal)
    NamedValues[VarName] = OldVal;
  else
    NamedValues.erase(VarName);

  
  // for expr always returns 0.0.
  return Constant::getNullValue(Type::getDoubleTy(TheContext));
}