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bug#36882: Qemu 4.2.0 build for x86_64-linux fails
From: |
Ludovic Courtès |
Subject: |
bug#36882: Qemu 4.2.0 build for x86_64-linux fails |
Date: |
Sun, 23 Feb 2020 12:32:21 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) |
Hi Mathieu,
Mathieu Othacehe <address@hidden> skribis:
> On master, when building qemu, this is the gcc include path (obtained
> with "gcc -v -x c -E /dev/null"):
>
> /gnu/store/adm2cx3ayabn1sp84nnjsk0672m800ip-flex-2.6.4/include
> /gnu/store/l86azr7r3p5631wj3kk329jl1y1mpjgy-bzip2-1.0.6/include
> ...
>
> /gnu/store/2plcy91lypnbbysb18ymnhaw3zwk8pg1-gcc-7.4.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.4.0/include
> [1]
>
> /gnu/store/2plcy91lypnbbysb18ymnhaw3zwk8pg1-gcc-7.4.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.4.0/include-fixed
> /gnu/store/ahqgl4h89xqj695lgqvsaf6zh2nhy4pj-glibc-2.29/include [2]
>
>
> We see that glibc comes last. So when building a program with "gcc
> -ffreestanding -m16", the first <stdint.h> header picked is the one from
> gcc (marked [1] above). This header contains:
>
> #ifndef _GCC_WRAP_STDINT_H
> #if __STDC_HOSTED__ <-- Set to 0 because of -ffreestanding option.
> # if defined __cplusplus && __cplusplus >= 201103L
> # undef __STDC_LIMIT_MACROS
> # define __STDC_LIMIT_MACROS
> # undef __STDC_CONSTANT_MACROS
> # define __STDC_CONSTANT_MACROS
> # endif
> # include_next <stdint.h>
> #else
> # include "stdint-gcc.h" <-- This one gets included.
> #endif
> #define _GCC_WRAP_STDINT_H
> #endif
>
>
> So the <stdint.h> from glibc (marked [2] above) is neved included. And
> that's good because this header would try to include <gnu/stubs-32.h>
> that our glibc does not provide.
[...]
> Now, what's happening on core-updates? Because of CPATH ->
> C_INCLUDE_PATH transition, we have a different behaviour. The same
> command as above states:
>
> ignoring duplicate directory
> "/gnu/store/jsjsczgr8xdnbdminl7lm2v56b7dq7lq-glibc-2.31/include"
> ...
> /gnu/store/kyypmcn2miyzllqqmcx28gvj89qnvhpi-flex-2.6.4/include
> ...
> /gnu/store/jsjsczgr8xdnbdminl7lm2v56b7dq7lq-glibc-2.31/include [1]
> ...
>
> /gnu/store/wl7zanqf0s9bfppggmv8qxqan71fjfw8-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/include
> [2]
>
> /gnu/store/wl7zanqf0s9bfppggmv8qxqan71fjfw8-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/include-fixed
>
> The glibc ignored seems to be the hardcoded one. The one from the
> C_INCLUDE_PATH is kept. So the <stdint.h> included is the one from glibc
> (marked [1] above), which triggers <gnu/stubs-32.h> inclusion and makes
> build fail.
Woow, thanks for the analysis.
It’s a bug on ‘core-updates’ that GCC’s headers come after libc’s. This
is what should be fixed IMO.
So is it expected that C_INCLUDE_PATH comes before the hard-coded GCC
include directory? How can we work around that?
Thanks!
Ludo’.
- bug#36882: Qemu 4.2.0 build for x86_64-linux fails, Mathieu Othacehe, 2020/02/21
- bug#36882: Qemu 4.2.0 build for x86_64-linux fails, Ludovic Courtès, 2020/02/21
- bug#36882: Qemu 4.2.0 build for x86_64-linux fails, Mathieu Othacehe, 2020/02/22
- bug#36882: Qemu 4.2.0 build for x86_64-linux fails,
Ludovic Courtès <=
- bug#36882: Qemu 4.2.0 build for x86_64-linux fails, Mathieu Othacehe, 2020/02/24
- bug#36882: Qemu 4.2.0 build for x86_64-linux fails, Ludovic Courtès, 2020/02/24
- bug#36882: Qemu 4.2.0 build for x86_64-linux fails, Mathieu Othacehe, 2020/02/25
- bug#36882: Qemu 4.2.0 build for x86_64-linux fails, Mathieu Othacehe, 2020/02/25
- bug#36882: Qemu 4.2.0 build for x86_64-linux fails, Ludovic Courtès, 2020/02/26
- bug#36882: Qemu 4.2.0 build for x86_64-linux fails, Marius Bakke, 2020/02/26