[PATCH] Store paren locations in IfStmt, WhileStmt, SwitchStmt.

[Richard Smith]

On Wed, Oct 1, 2014 at 3:12 PM, Alexander Kornienko <alexfh at google.com>
wrote:

> >>! In D5528#5, @doug.gregor wrote:
> > In non-macro cases, one can extract the locations of the parentheses
> using the lexer. Personally, I don't think the benefits of being able to
> extract the locations of the parentheses efficiently or in the macro cases
> outweigh the disadvantages of bloating the AST further.
>
> For the context: this patch resulted from the discussion on D5395.
>
> I understand your concerns about bloating the AST. Some locations can be
> relatively easy found by re-lexing small parts of the input. One problem
> with this approach is that everyone who needs these locations spends time
> looking for a way to get them and then writing their own implementation. Is
> there a document or a comment describing the high-level approach to what is
> considered worthy storing in the AST?
>
> Also, it may be reasonable to add utility methods in the AST classes (or
> free-standing functions in clang/AST headers) for retrieving some less
> frequently used locations of syntactic constructs in non-macro cases (e.g.
> WhileStmt::findRParenLoc() which would find the first non-comment token
> after getCond()->getLocEnd()). What do you think?
>

At the least, we should provide a version of Lexer::findLocationAfterToken
that finds the location *of* the token, rather than skipping past it.


> And while you're here, one more question related to D5395:
> what is the reason why the statements ending with a semicolon do not
> include the semicolon in their source range (with exception of the
> NullStmt)? Is it feasible to extend the source range to include it? (and
> what would you expect to break in this case?)
>

Perhaps it's time to add an ExprStmt to represent an expression-statement,
along with the location of its semicolon.


> http://reviews.llvm.org/D5528
>
>
>
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