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

[John McCall]

On Oct 25, 2012, at 1:39 PM, Lang Hames wrote:
> 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
>   #pragma STDC FP_CONTRACT 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? 

Other pragmas, maybe.  You could potentially check for all the pragma annotation tokens.

> Does this seem like a reasonable approach?

It seems fine.

John.

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