C++ support in ARMCC (Keil) compiler/toolchain ?

Dave Nadler <drn@nadler.com> wrote:
> No, it is their own implementation, and is not based on GCC.
> They claim C++ is validated with Plum-Hall, but do not publish the
> test results.

> ARM publishes the same compiler with additional chips supported
> in a different package, but it is still based on the proprietary
> Keil compiler and not GCC.

The compiler bundled uVision is a slightly customised version of the
ARM Compiler which is also part of RVDS.

http://www.arm.com/products/tools/arm-compiler.php

After the acquisition of Keil by ARM the use of the original Keil C
compiler for ARM has been superseded by the use of the ARM Compiler
(formerly RVCT) which is a full optimising C and C++ compiler.

-p
-- 
Paul Gotch
--------------------------------------------------------------------

d_s_klein <d_s_klein@yahoo.com> wrote:
> Any idea what I should be doing with the .tgz file I downloaded from
> keil.com?  The one that they were required to publish because of the
> GPL code in their ARM compiler?

Which tgz file? Do you mean using uVision with CodeSourcery G++ Lite?

The ARM compiler distributed with the latest version of uVision is a
customised version of the ARM Compiler
(http://www.arm.com/products/tools/arm-compiler.php) and is not based
on GPL code.

-p
-- 
Paul Gotch
--------------------------------------------------------------------

Hi Dave,

Dave Nadler wrote:
> On Apr 1, 1:24 am, hamilton <hamil...@nothere.com> wrote:
>> On 3/31/2010 7:11 PM, D Yuniskis wrote:
>>
>>> hamilton wrote:
>>>> Are there any web sites available that compares the amount of overhead
>>>> C++ carries compared to just plain C ?
>>> In what context? I.e., if you "write C in C++" what
>>> overhead did you anticipate?
>>> I've often wanted to recode an existing project in C (or C++)
>>> to compare the overall size/speed/etc. with C++ (or C).
>>> But, even that wold be an unfair comparison as you (at least, *I*)
>>> approach designs in C (C++) differently than I do in C++ (C).
>> Yes, good point.
>>
>> Most new "embedded programmers" are from the desktop world.
>>
>> I would like to know, as you stated, what would be the overhead for the
>> same program using C++ constructs.
>>
>> By your comment, I doubt too many programmers know that there is a
>> difference.
>>
>> I'll look over the Keil web site and see if there is anything there.
> 
> Comparing C and C++ is a bit of apples and oranges.
> Properly written C++ can reduce source code size, reduce
> execution size and time, improve maintainability. Bad C++

I'd say "that depends".  I think a problem with much C++ is
people trying to "just apply" already written classes to
their problem-at-hand.  E.g., similar to trying to use
C "standard libraries" blindly.

IME, it is even more important to craft your classes *to*
the needs of your application (than it is to make the standard
C libraries "fit").

I've also seen some analysis that C++ hurts cache performance
(except for HUGE cache's) as it doesn't exploit locality of
reference as much as C code might (again, loosely referring
to "something" representative of C vs. "something else"
representative of C++)

> is vastly more horrid than bad C, which can be horrid.
> Use of C++ by the inexperienced is usually scary.

Agreed.

> And you'll be unpleasantly surprised if you say
> accidentally drag in the C++ library functions for
> stream IO into a small micro...

Yes, but that's true if you drag many C standard library
functions into that same small micro.

I think writing a standard library is a great exercise
for developers approaching a new processor.  It gives
you a quick feel of what various "typical" operations cost.
E.g., looking at the code produced by the compiler for many
of math.h can quickly assuage -- or reinforce -- fears about
using floating point math in a design.

> Hope that helps !
> Best Regards, Dave
> 
> PS: If anybody knows of a well-written doc discussing
> C++ for embedded in depth, we'd be much obliged !

I'll search for the cache analysis I mentioned above.
Sure would be nice to have google running on my
repository!  :-/