[cfe-dev] GotoStmt::getSourceRange, bug?

[Steve Naroff]

On Sep 6, 2007, at 9:42 AM, Ted Kremenek wrote:

> The question is that do we have enough extent information recorded in
> GotoStmt to accurately recreate the full source range for a goto
> statement?

Not currently. It looks like we need to add a "LabelLoc" to the AST  
(this is already passed into the actions, so it's trivial to do).  
Make sense?

Thanks for finding this,

snaroff


> I think there is a bug in the current implementation of getSourceRange
> for GotoStmt:
>
>
>    class GotoStmt : public Stmt {
>      LabelStmt *Label;
>      SourceLocation GotoLoc;
>    public:
>      ...
>      virtual SourceRange getSourceRange() const {
>        return SourceRange(GotoLoc, Label->getLocEnd());
>      }
>      ...
>    };
>
>
> I believe that getting the end SourceLocation using Label->getLocEnd()
> is incorrect.  While the target LabelStmt is referenced by GotoStmt,
> it isn't a substatement in the tree.  Consider the following snippet
> of code:
>
>    l1: goto l1;
>
> Here, the GotoStmt is a substatement of the LabelStmt for "l1".  The
> implementation of getSourceRange() in LabelStmt is as follows (notice
> the call to SubStmt->getLocEnd):
>
>
>    class LabelStmt : public Stmt {
>      IdentifierInfo *Label;
>      Stmt *SubStmt;
>      SourceLocation IdentLoc;
>    public:
>      ...
>      virtual SourceRange getSourceRange() const {
>        return SourceRange(IdentLoc, SubStmt->getLocEnd());
>      }
>     ....
>    };
>
>
> There is an unbounded recursion here.  While LabelStmt is correctly
> calling getLocEnd for its substatement, GotoStmt is incorrectly
> calling getLocEnd for the target LabelStmt.
>
> The question is that do we have enough extent information recorded in
> GotoStmt to accurately recreate the full source range for a goto
> statement?
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