Re: Builtins in `std'

[Gabriel Dos Reis <Gabriel dot Dos-Reis at cmla dot ens-cachan dot fr>]

Mark Mitchell <mark@codesourcery.com> writes:

|   OK.  But since we're violating the ODR here, is there a chance that
|   a user notices it? (I'm asking because I'm not sure)
| 
| I can't think of any way that they could.  But, it's hard to convince
| yourself 100% of these things.
| 
|   | In particular, I'm trying to fix a regression on code like:
|   | 
|   |   extern "C" double fabs (double) {}
|   | 
|   |   namespace std { 
|   |     double fabs (double) {}
|   |   } 
|   | 
|   | (A user is allowed to do this; they might have a different library
|   | implementation or something.)
| 
|   The above is not allowed.
| 
| Because the user is not allowed to put things in `std', or for some
| other reason?

Basically for the same reason: Because the user is not allowed to put
things in std::, nor declare a C-library name with a C-linkage.

But now that I understand you concerns, I completely agree that the
optimized versions should be named __builtin_xxx.  

[...]

| I'm trying to solve two problems at once: fix the bizarre error for
| the code above, and also simplify the compiler.  There's a lot of
| (partially wrong) logic in the compiler to deal with users redeclaring
| builtins; it would be simpler if we could just avoid that hapenning by
| not sticking builtins in `std'.

I understand.  I think your approach is Good :-)

-- Gaby