Your message dated Sun, 31 Mar 2013 12:32:44 +0000
with message-id <e1umhre-0004yc...@franck.debian.org>
and subject line Bug#704111: fixed in clang 1:3.0-6.2
has caused the Debian Bug report #704111,
regarding clang fails to correctly implement hard float ABI during default
compiles due to rediculously low default CPU setting.
to be marked as done.
This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.
(NB: If you are a system administrator and have no idea what this
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immediately.)
--
704111: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=704111
Debian Bug Tracking System
Contact ow...@bugs.debian.org with problems
--- Begin Message ---
Package: clang
Version: 1:3.0-6.1
Severity: grave
x-debbugs-cc: debian-...@lists.debian.org; cfe-...@cs.uiuc.edu
(note for non-debian people reading this, the version of clang in debian
wheezy is a 3.0 based version which already has patches to make it
invoke the linker with appropriate arguments. The llvm version also
appears to be 3.0 again somewhat patched by debian)
I recently discovered that the version of clang in debian wheezy and
raspbian wheezy does not work correctly on either debian armhf or
raspbian. It seems the problem is that clang can't work out what CPU
type it should be using and defaults to something very low (specifically
arm7tdmi). With this CPU selected clang silently fails to properly use
the hard float ABI and as such any armhf code it generates is broken and
won't call floating point routines correctly. It also causes an
assertion failure in the bfd linker (but links successfully with the
gold linker). Setting the CPU type to something sensible makes it
implement the hard float ABI correctly and also stops the assertion
failure in the bfd linker.
I have managed to figure out how to patch clang to change the default
CPU for armhf (patch attatched). However i'm not sure what it is best to
set it to for debian armhf*. In particular this block of code from just
below where my patch is applied seems to map all armv7 variants to a CPU
type of "coretex-a8".
return llvm::StringSwitch<const char
*>(MArch)
.Cases("armv2",
"armv2a","arm2")
.Case("armv3",
"arm6")
.Case("armv3m",
"arm7m")
.Cases("armv4", "armv4t",
"arm7tdmi")
.Cases("armv5", "armv5t",
"arm10tdmi")
.Cases("armv5e", "armv5te",
"arm1026ejs")
.Case("armv5tej",
"arm926ej-s")
.Cases("armv6", "armv6k",
"arm1136jf-s")
.Case("armv6j",
"arm1136j-s")
.Cases("armv6z", "armv6zk",
"arm1176jzf-s")
.Case("armv6t2",
"arm1156t2-s")
.Cases("armv7", "armv7a", "armv7-a",
"cortex-a8")
.Cases("armv7r", "armv7-r",
"cortex-r4")
.Cases("armv7m", "armv7-m",
"cortex-m3")
.Case("ep9312",
"ep9312")
.Case("iwmmxt",
"iwmmxt")
.Case("xscale",
"xscale")
.Cases("armv6m", "armv6-m",
"cortex-m0")
// If all else failed, return the most base CPU LLVM
supports.
.Default("arm7tdmi");
Now it is my understanding that "traditional cortex a8" includes CPU
features not required by debian armhf. Specifically neon and the extra
vfp registers. The questions I have are
1: What does the "coretex-a8" CPU setting imply for clang/llvm? in
particular does it imply neon and the extra vfp registers?
2: If noone can provide an answer to the above question then taking into
the account how late we are in the freeze should we play it safe and
specify a lower (armv6) CPU version to make sure that neon and the extra
vfp registers don't get accidently used. I personally think that the
answer is yes but I'm open to arguments.
If I get no response to this within about a weak I intend to attach a
nmu diff containing a version of the patch that sets the default set to
armv6. Then file a pre-approval request with the release team. Finally
if the release team approves and noone objects I intend to upload the NMU.
Description: Fix CPU type default for armhf
Without this patch clang defaults to a CPU type of "arm7tdmi" which
does not work correctly with -mfloat-abi=hard leading to broken
code.
Author: Peter Michael Green <plugw...@debian.org>
---
The information above should follow the Patch Tagging Guidelines, please
checkout http://dep.debian.net/deps/dep3/ to learn about the format. Here
are templates for supplementary fields that you might want to add:
Origin: <vendor|upstream|other>, <url of original patch>
Bug: <url in upstream bugtracker>
Bug-Debian: http://bugs.debian.org/<bugnumber>
Bug-Ubuntu: https://launchpad.net/bugs/<bugnumber>
Forwarded: <no|not-needed|url proving that it has been forwarded>
Reviewed-By: <name and email of someone who approved the patch>
Last-Update: <YYYY-MM-DD>
Index: clang-3.0/tools/clang/lib/Driver/Tools.cpp
===================================================================
--- clang-3.0.orig/tools/clang/lib/Driver/Tools.cpp 2013-03-27 19:50:18.000000000 +0000
+++ clang-3.0/tools/clang/lib/Driver/Tools.cpp 2013-03-27 19:53:28.000000000 +0000
@@ -442,6 +442,9 @@
if (Arg *A = Args.getLastArg(options::OPT_march_EQ)) {
// Otherwise, if we have -march= choose the base CPU for that arch.
MArch = A->getValue(Args);
+ } else if (Triple.getEnvironment() == llvm::Triple::GNUEABIHF) {
+ // Use armv7-a for armhf
+ MArch = "armv7-a";
} else {
// Otherwise, use the Arch from the triple.
MArch = Triple.getArchName();
--- End Message ---
--- Begin Message ---
Source: clang
Source-Version: 1:3.0-6.2
We believe that the bug you reported is fixed in the latest version of
clang, which is due to be installed in the Debian FTP archive.
A summary of the changes between this version and the previous one is
attached.
Thank you for reporting the bug, which will now be closed. If you
have further comments please address them to 704...@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.
Debian distribution maintenance software
pp.
Peter Michael Green <plugw...@debian.org> (supplier of updated clang package)
(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmas...@debian.org)
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
Format: 1.8
Date: Thu, 28 Mar 2013 09:02:01 +0000
Source: clang
Binary: clang libclang1 libclang-dev libclang-common-dev
Architecture: source amd64
Version: 1:3.0-6.2
Distribution: unstable
Urgency: low
Maintainer: LLVM Packaging Team <pkg-llvm-t...@lists.alioth.debian.org>
Changed-By: Peter Michael Green <plugw...@debian.org>
Description:
clang - Low-Level Virtual Machine (LLVM), C language family frontend
libclang-common-dev - clang library - Common development package
libclang-dev - clang library - Development package
libclang1 - clang library
Closes: 704111
Changes:
clang (1:3.0-6.2) unstable; urgency=low
.
* Non-maintainer upload with maintainer's approval.
* 29-set-default-cpu-for-armhf.diff increase default cpu for armhf builds.
Previous absurdly low default did not work correctly with
-mfloat-abi=hard leading to broken code. (Closes: #704111)
+ Use armv6 as new default because in clang 3.0 armv7 implies features that
we don't require in debian armhf (extra fpu registers and neon)
* 30-powerpc-no-altivec.patch disable altivec by default on powerpc because
debian powerpc does not require altivec (patch cherry picked from ubuntu)
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0bea968021509dfef0b81d3e5fda9b8f 23095 devel optional
clang_3.0-6.2.debian.tar.gz
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26ef8728a9c9622a5e65b34221f10483 3268184 devel optional
libclang1_3.0-6.2_amd64.deb
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libclang-dev_3.0-6.2_amd64.deb
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