Re: [PATCH, ARM] Don't use __thumb2__ to select _REENT_SMALL

[Richard Earnshaw <rearnsha at arm dot com>]

On Tue, 2009-06-02 at 14:46 +0100, Paul Brook wrote:
> On Tuesday 02 June 2009, Richard Earnshaw wrote:
> > This cost me at least a couple of hours debugging at the weekend; I was
> > trying to work out why my file handles were all corrupted when compiling
> > code for Thumb-2.  It turns out that Newlib's config.h was changing the
> > ABI depending on the instruction set it was compiling for -- a big No
> > No, since code is supposed to interwork freely between the two ISAs!
> 
> I'm fairly sure I tested this, and concluded that it had no effect on the 
> external library ABI. In fact I think I fixed bugs related to this.
> i.e. this only matters if you're trying to compile part of the library as 
> Thumb-2 and part as ARM. Do we really care about that? Or did I miss 
> something?
> 
> Paul

Yes, this leaks out into user code -- at least it does for me.  Try
building the standard arm-eabi multilib tools and then running the gcc
testsuite with -mcpu=cortex-a8 and -mthumb.  Programs such as
gcc.c-torture/exectute/fprintf-1.c will then fail.

The definition of stdout is:
#define stdout  (_REENT->_stdout)

Which thus depends on the layout of _REENT.

R.
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