[cfe-commits] [PATCH] Multiple pragmas at the start of a compound statement.

Lang Hames lhames at gmail.com
Thu Nov 1 10:53:49 PDT 2012


On Thu, Oct 25, 2012 at 1:39 PM, Lang Hames <lhames at gmail.com> wrote:

> Hi All,
> Tim Northover pointed out that there's a flaw in my recent FP_CONTRACT
> patch (r166383). That patch restricted FP_CONTRACT (or rather
> tok::annot_pragma_fp_contract) to appearing as the first token in a
> compound statement. The problem with my patch is that it prohibits things
> like:
> void foo() {
>   #pragma MS_STRUCT ON
>   // ...
> }
> Which isn't prohibited by the C99 spec, and I think seems reasonable.
> A simple solution to the problem is to loop at the start of a compound
> statement parsing tokens that can reasonably appear there (FP_CONTRACT,
> MS_STRUCT, maybe others?), then break out of that look when an unhandled
> token encountered. Attached is a patch that implements this approach,
> processing FP_CONTRACT and MS_STRUCT pragmas at the start of compound
> statements before falling through.
> Not being a language lawyer, is what else should be handled in this loop?
> Does this seem like a reasonable approach?
> - Lang.
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