blob: f4ab283d54543196fed55b89e1aed364bda79ff4 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
|
graphic: 0.911
semantic: 0.907
user-level: 0.898
permissions: 0.881
vnc: 0.880
register: 0.879
peripherals: 0.877
assembly: 0.871
virtual: 0.870
kernel: 0.863
KVM: 0.859
files: 0.858
debug: 0.855
mistranslation: 0.855
TCG: 0.854
hypervisor: 0.850
risc-v: 0.847
ppc: 0.843
device: 0.840
performance: 0.839
VMM: 0.827
PID: 0.825
arm: 0.818
architecture: 0.817
socket: 0.781
x86: 0.755
network: 0.754
boot: 0.747
i386: 0.428
Parallel builds fail (make -j >=2) when using --extra-cflags "--save-temps"
specs:
Host kernel: Linux 4.19.16-1-lts
Host type: x86_64 GNU/Linux
Host distro: Archlinux
Guest: we never get that far
QEMU commit: 9f33051abce238ab43a23125e237aac8b0931b88
steps:
# fresh copy of the latest commit
> git clone https://git.qemu.org/git/qemu.git
# separate build dir
> mkdir build
> cd build
# sample configuration for riscv (this happens for other targets as well)
> ../qemu/configure --target-list=riscv64-softmmu --enable-debug --extra-cflags='-O0 -g3 -save-temps' --prefix=/install/riscv-qemu
# this will fail (see attached log file)
> make -j 2
It seems the --save-temps is what breaks things for me, the following works:
../qemu.git/configure --target-list=riscv64-softmmu --enable-debug --extra-cflags="-O0 -g3" && make -j9
rm -rf and start again with:
../qemu.git/configure --target-list=riscv64-softmmu --enable-debug --extra-cflags="-O0 -g3 --save-temps"
falls over with lines like:
block/trace.h: In function ‘_nocheck__trace_nbd_co_request_fail’:
block/trace.h:3141:73: error: ‘_TRACE_NBD_CO_REQUEST_FAIL_DSTATE’ undeclared (first use in this function); did you mean ‘TRACE_NBD_CO_REQUEST_FAIL_BACKEND_DSTATE’?
if (trace_event_get_state(TRACE_NBD_CO_REQUEST_FAIL) && qemu_loglevel_mask(LOG_TRACE)) {
^~~~~~~~~~~~~~~~~~~~
TRACE_NBD_CO_REQUEST_FAIL_BACKEND_DSTATE
which implies something getting in the way of making the trace files.
it seems like that "-save-temps" in "cflags" is the culprit. I removed it and it was possible to build with 8 instances:
# removed "-save-temps" from the "cflags"
> ./qemu/configure --target-list=riscv64-softmmu --enable-debug --extra-cflags='-O0 -g3' --prefix=/install/riscv-qemu
# build without any problem
> make -j 8
A workaround for this is to use "-save-temps=obj" which ensures the temps are dumped in the object directory. I suspect there is a clash somewhere between what save temps dumps and some of the files we generate for tracing.
putting the temporary files in object dir works as well: -save-temps=obj
# "-save-temps=obj" from the "cflags"
> ./qemu/configure --target-list=riscv64-softmmu --enable-debug --extra-cflags='-O0 -g3 -save-temps=obj' --prefix=/install/riscv-qemu
# build again without any problem
> make -j 8
Hi; I'm going to close this bug because there's no way that QEMU's build process can handle being passed -save-temps via --extra-cflags, because this will cause GCC to use the same output files for multiple different source files, and they will clash. (Even with a non-parallel build, one compile is going to win, and the temp files for the first compile of the pair will just be overwritten and lost.)
As you've discovered, the right way to do this is to use -save-temps=obj, which will correctly put the temporary files in different places for each generated object file, so they don't conflict with each other.
|
