[Patch, avr] Add device name to cpp_builtins

[Senthil Kumar Selvaraj]

On Mon, Jul 28, 2014 at 08:09:28PM +0200, Georg-Johann Lay wrote:
> Senthil Kumar Selvaraj schrieb:
> >The below patch adds a new preprocessor define for the device name
> >(__AVR_DEVICE_NAME__) that was passed to the compiler.
> >
> >While the device name macro (say __AVR_ATmega128__) can be used to check
> >for a specific device, there is no way right now for code to get the
> >device name it is being compiled against (without checking
> >for every possible device).
> 
> Shouldn't this also be added to the documentation?
> There's a section "AVR Built-in Macros" in the manual.

Thanks for reminding me, Johann. Here's the patch - if ok, could someone
commit please?

Regards
Senthil

2014-07-30  Senthil Kumar Selvaraj  <senthil_kumar.selvaraj@atmel.com>

	* doc/invoke.texi (AVR Options): Add documentation about 
	__AVR_DEVICE_NAME__ built-in macro.

diff --git gcc/doc/invoke.texi gcc/doc/invoke.texi
index 7cebb9e..e201496 100644
--- gcc/doc/invoke.texi
+++ gcc/doc/invoke.texi
@@ -13114,6 +13114,14 @@ the device name as from the AVR user manual. The difference between
 If @var{device} is not a device but only a core architecture like
 @code{avr51}, this macro will not be defined.
 
+@item   __AVR_DEVICE_NAME__
+Setting @code{-mmcu=@var{device}} defines this built-in macro to
+the device's name. For example, with @code{-mmcu=atmega8} the macro
+will be defined to @code{atmega8}.
+
+If @var{device} is not a device but only a core architecture like
+@code{avr51}, this macro will not be defined.
+
 @item __AVR_XMEGA__
 The device / architecture belongs to the XMEGA family of devices.