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Bug 586846 - flag-o-matic.eclass: strip-flags should allow -mthumb
Summary: flag-o-matic.eclass: strip-flags should allow -mthumb
Status: RESOLVED FIXED
Alias: None
Product: Gentoo Linux
Classification: Unclassified
Component: Eclasses (show other bugs)
Hardware: ARM Linux
: Normal normal
Assignee: Gentoo Toolchain Maintainers
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2016-06-23 19:44 UTC by Michael Weiser
Modified: 2016-07-01 03:45 UTC (History)
0 users

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Package list:
Runtime testing required: ---

Attachments
allow -mthumb in strip-flags (flag-o-matic-mthumb.patch,567 bytes, patch)
2016-06-23 19:44 UTC, Michael Weiser 		Details | Diff
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Description Michael Weiser 2016-06-23 19:44:37 UTC 
Created attachment 438592 [details, diff]
allow -mthumb in strip-flags

From what I gather thumb2 is the standard and most efficient instruction set for current ARM CPUs. So I'd like to compile my whole armv7 system with thumb2 mode enabled. But strip-flags strips out -mthumb. This causes for example glibc not to be compiled with thumb2 enabled.

In my understanding -mthumb is an architecture tuning flag analogous to -mcpu and -mfpu. I have not found any reference to miscompilations or other negative impact caused by it.

Can we please allow -mthumb in strip-flags?
Comment 1 Michael Weiser 2016-06-24 12:56:55 UTC 
Conversely, it should allow -marm as well to disable thumb explicitly.
Comment 2 Ryan Hill (RETIRED) gentoo-dev 2016-07-01 03:45:10 UTC 
Added both.

commit 9f6a8c6ddf7abf1774b63e40a9785a94ba168fe7
Author: Ryan Hill <rhill@gentoo.org>
Date:   Thu Jun 30 21:42:09 2016 -0600

    flag-o-matic.eclass: Add -mthumb/-marm (bug #586846).