Re: [TF-M] [Request For Comments] apply "-fno-builtin" as default compiler flags - TF-M

22 Jan 2020


      Hi,
As mentioned, we have created the patch here to apply "-fno-builtin":
https://review.trustedfirmware.org/c/trusted-firmware-m/+/3217
Will keep it there for a while for validation purpose. Please help to test this patch if you are run on non-default platforms (those not listed in the platform folder).
Any comment can reply or put comments under the issue:
https://developer.trustedfirmware.org/T653
Thanks.
/Ken
From: TF-M tf-m-bounces@lists.trustedfirmware.org On Behalf Of Tamas Ban via TF-M
Sent: Thursday, January 9, 2020 4:42 PM
To: tf-m@lists.trustedfirmware.org
Subject: Re: [TF-M] [Request For Comments] apply "-fno-builtin" as default compiler flags
Hi Thomas,
Just for my understanding:
*   Does IAR provide a C std. lib as part of IAR toolchain package?
  *   How the std C lib linked to the image? Does user provide an explicit flag which std. C lib to linked to the image?
Tamas
From: TF-M <tf-m-bounces@lists.trustedfirmware.orgmailto:tf-m-bounces@lists.trustedfirmware.org> On Behalf Of Thomas Törnblom via TF-M
Sent: 08 January 2020 12:45
To: tf-m@lists.trustedfirmware.orgmailto:tf-m@lists.trustedfirmware.org
Subject: Re: [TF-M] [Request For Comments] apply "-fno-builtin" as default compiler flags
The IAR toolchain does not produce any special "builtin" calls and thus does not have any flag similar to "-fno-builtin".
/Thomas
Den 2020-01-08 kl. 03:53, skrev Ken Liu via TF-M:
Hi,
ï¿½
As TF-M needs runtime APIs so we are creating the Secure Partition runtime library, code is ready but we have not forwarded all necessary runtime APIs to the version TF-M implemented, this was caused by the toolchain optimization for built-in APIs, such as:
ï¿½
- Forward printf(%s) to puts if there is only one string parameter.
- ARMCLANG would forward memxxx API into an optimized variant.
ï¿½
With the '-fno-builtin' flags set in the toolchain, this optimization would be disabled so that user just implement the same name built-in to replace the toolchain version.
ï¿½
Please help to check these point before applying '-fno-builtin' and provide your feedback:
ï¿½
- Could toolchains out of ARMCLANG and GNUARM have a similar flag?
- Would it affect your project setting and how does it affect?
ï¿½
Please help to feedback. I will keep this thread open for ~1 week and let's get a conclusion after this.
ï¿½
Thanks!
ï¿½
/Ken
--
Thomas Tï¿½rnblom, Product Engineer
IAR Systems AB
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