[cfe-dev] SourceLocation TODO

[Chris Lattner]

On May 8, 2008, at 8:26 PM, caiwei wrote:

> Taking a look at the ObjC Rewriter for examples, I want to change  
> the operator * to << (source to source) .
>
> I create a new BinaryOperator and replace the Expr .
>
>
>    rhs = new IntegerLiteral( Res, BO->getRHS()->getType(), BO- 
> >getRHS()->getExprLoc() );
> // change * to <<
>    Replacement = new BinaryOperator(BO->getLHS(), rhs,
>                                     BO->Shl, BO->getType(), BO- 
> >getLHS()->getExprLoc());
> //replace the expression
>    assert( !Rewrite.ReplaceStmt(BO, Replacement) );
>
>
> but the output SourceLocation  has some problem in the result source  
> code, when there are two  * Operateor more.

I assume that you mean that you have problems rewriting things like  
"(x*2)*2".

This is because you're deleting the AST:

>    // change * to <<
>    Replacement = new BinaryOperator(BO->getLHS(), rhs,
>                                     BO->Shl, BO->getType(), BO- 
> >getLHS()->getExprLoc());

Here the old multiply node and the << both point to the LHS AST.

>
>   delete BO;

This deletes the "*" AST and the LHS/RHS.  To avoid having it delete  
the LHS, set the LHS of the multiply to null before you delete it.

-Chris