1032528 - With clang-cl, the linker major version does not match the compiler suite version

Status: RESOLVED FIXED

(Firefox Build System :: General, defect)

Description

[(Away)]

I started with |cmake -G "Visual Studio 12" ..\llvm|. I confirmed that LLVM.sln is "Format Version 12.00". Then I built that with VC12 (VS2013). But it looks like my clang-cl still thinks that it's version 11. When configure sees it mixed with the VC12 linker, it complains:

0:14.54 configure: error: The linker major version, 12.00.30501.0,  does not match the compiler suite version, 11.

Comment 1

[Stephen Crane]

Clang is defaults to identifing as VC11. You can change that with -fmsc-version=vc12, but I have not tested this, so there may be other problems.

Comment 2

[(Away)]

 0:14.35 error(clang): invalid value 'vc12' in '-fmsc-version=vc12'

The help says:
  -fmsc-version=<value> Microsoft compiler version number to report in _MSC_VER (0 = don't define it (default))

The _MSC_VER for VC12 is 1800 so I tried that instead. Still the same error as comment 0. (Though is that even the right thing to do? Do we want _MSC_VER at all in these builds?)

Comment 3

[(no longer active)]

(In reply to David Major [:dmajor] from comment #2)
>  0:14.35 error(clang): invalid value 'vc12' in '-fmsc-version=vc12'
> 
> The help says:
>   -fmsc-version=<value> Microsoft compiler version number to report in
> _MSC_VER (0 = don't define it (default))
> 
> The _MSC_VER for VC12 is 1800 so I tried that instead. Still the same error
> as comment 0.

Hmm, try adding -fmsc-version=1800 to CFLAGS and CXXFLAGS exports in your mozconfig?

> (Though is that even the right thing to do? Do we want
> _MSC_VER at all in these builds?)

Yes, we do!  clang-cl tries to be a drop-in replacement for cl.exe.

Comment 4

[(Away)]

> Hmm, try adding -fmsc-version=1800 to CFLAGS and CXXFLAGS exports in your
> mozconfig?

Er, that's what I tried in comment 2, unless I'm misunderstanding your request.

Comment 5

[(no longer active)]

(In reply to David Major [:dmajor] from comment #4)
> > Hmm, try adding -fmsc-version=1800 to CFLAGS and CXXFLAGS exports in your
> > mozconfig?
> 
> Er, that's what I tried in comment 2, unless I'm misunderstanding your
> request.

Weird...  What do you get if you run these commands?

echo _MSC_VER test.c
clang-cl -E -fmsc-version=1800 test.c

I get 1800, but I suspect you will see 1700?

Do you know which LLVM commit your clang-cl has been built from?

Comment 6

[(no longer active)]

Also, can you please paste your mozconfig here again?  I can't find the link you gave me the other day...

Comment 7

[(Away)]

> I get 1800, but I suspect you will see 1700?

$ clang-cl -E -fmsc-version=1800 test.c
#line 1 "test.c"
#line 1 "<built-in>"
#line 1 "<built-in>"
#line 151 "<built-in>"
#line 1 "<command line>"
#line 1 "<built-in>"
#line 1 "test.c"
1800

> Do you know which LLVM commit your clang-cl has been built from?

I don't have the exact commit. It was tip from roughly June 26.

> Also, can you please paste your mozconfig here again?

mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/objclang
export CC=clang-cl
export CXX=clang-cl
export CFLAGS="-fallback -fmsc-version=1800"
export CXXFLAGS="-fallback -fmsc-version=1800"
export MOZ_CFLAGS_NSS="-fallback -fmsc-version=1800"
export MOZILLA_OFFICIAL=1
ac_add_options --enable-crashreporter
ac_add_options --enable-release

Comment 8

[(Away)]

I got it working if I change CC/CXX to:

export CC="clang-cl -fmsc-version=1800"
export CXX="clang-cl -fmsc-version=1800"

(Or at least it gets past that part of configure.)

I think it's because of: http://dxr.mozilla.org/mozilla-central/source/build/autoconf/toolchain.m4#29

Comment 9

[(no longer active)]

(In reply to David Major [:dmajor] from comment #8)
> I got it working if I change CC/CXX to:
> 
> export CC="clang-cl -fmsc-version=1800"
> export CXX="clang-cl -fmsc-version=1800"
> 
> (Or at least it gets past that part of configure.)

Wow!!

> I think it's because of:
> http://dxr.mozilla.org/mozilla-central/source/build/autoconf/toolchain.m4#29

Oh yes, you're absolutely right!  I wrote that code.  :(

Comment 10

[(no longer active)]

Attachment: Use CFLAGS when determining the compiler version in case it can be affected by what is there; r=glandium

This for example allows us to use -fmsc-version in CFLAGS/CXXFLAGS
with clang-cl.

Comment 11

[(no longer active)]

Comment on attachment 8450746 [details] [diff] [review]
Use CFLAGS when determining the compiler version in case it can be affected by what is there; r=glandium

David, do you mind testing this please?

Comment 12

[(Away)]

Comment on attachment 8450746 [details] [diff] [review]
Use CFLAGS when determining the compiler version in case it can be affected by what is there; r=glandium

Review of attachment 8450746 [details] [diff] [review]:
-----------------------------------------------------------------

s/CXXFLAGC/CXXFLAGS/

With that change, and my mozconfig reverted to comment 7, it works.

Comment 13

[Mike Hommey [:glandium]]

Comment on attachment 8450746 [details] [diff] [review]
Use CFLAGS when determining the compiler version in case it can be affected by what is there; r=glandium

Review of attachment 8450746 [details] [diff] [review]:
-----------------------------------------------------------------

::: build/autoconf/toolchain.m4
@@ +30,3 @@
>  EOF
>  read dummy cxxcompiler CXX_VERSION <<EOF
> +$($CXX -E $CXXFLAGC conftest.c 2>/dev/null | grep COMPILER)

CXXFLAGS

Comment 14

[(no longer active)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/523ef80786ad

Comment 15

[(no longer active)]

Wow, this broke b2g builds!!

https://tbpl.mozilla.org/php/getParsedLog.php?id=43144548&tree=Mozilla-Inbound#error0
https://hg.mozilla.org/integration/mozilla-inbound/rev/abd9d0c21e7e

Comment 16

[(no longer active)]

Ah, of course we want CPPFLAGS too.

https://hg.mozilla.org/integration/mozilla-inbound/rev/d6ae573ff152

Comment 17

[Tim Taubert [:ttaubert] (inactive)]

https://hg.mozilla.org/mozilla-central/rev/d6ae573ff152