[Bug 1904259] Re: include/qemu/atomic.h:495:5: error: misaligned atomic operation may incur significant performance penalty (Clang 11; Ubuntu 16 i686)

[Launchpad Bug Tracker]

[Expired for Ubuntu because there has been no activity for 60 days.]

** Changed in: ubuntu
       Status: Incomplete => Expired

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https://bugs.launchpad.net/bugs/1904259

Title:
  include/qemu/atomic.h:495:5: error: misaligned atomic operation may
  incur significant performance penalty (Clang 11; Ubuntu 16 i686)

Status in QEMU:
  Expired
Status in Ubuntu:
  Expired

Bug description:
  Hello.
  I haven't found any "official" executables, for emulating RISC-V (32bit; 
64bit) so I had to compile those myself.

  I found that auto-generated build scripts, for Ninja, contained some
  warnings interpreted as errors:

  
  oceanfish81@gollvm:~/Desktop/qemu/build$ ninja -j 1
  [2/1977] Compiling C object libqemuutil.a.p/util_qsp.c.o
  FAILED: libqemuutil.a.p/util_qsp.c.o 
  clang-11 -Ilibqemuutil.a.p -I. -I.. -Iqapi -Itrace -Iui -Iui/shader 
-I/usr/include/glib-2.0 -I/usr/lib/i386-linux-gnu/glib-2.0/include 
-I/usr/include/gio-unix-2.0/ -Xclang -fcolor-diagnostics -pipe -Wall 
-Winvalid-pch -Werror -std=gnu99 -O2 -g -m32 -D_GNU_SOURCE 
-D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes 
-Wredundant-decls -Wundef -Wwrite-strings -Wmissing-prototypes 
-fno-strict-aliasing -fno-common -fwrapv -Wold-style-definition -Wtype-limits 
-Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body 
-Wnested-externs -Wendif-labels -Wexpansion-to-defined 
-Wno-initializer-overrides -Wno-missing-include-dirs -Wno-shift-negative-value 
-Wno-string-plus-int -Wno-typedef-redefinition 
-Wno-tautological-type-limit-compare -Wno-psabi -fstack-protector-strong 
-isystem /home/oceanfish81/Desktop/qemu/linux-headers -isystem linux-headers 
-iquote /home/oceanfish81/Desktop/qemu/tcg/i386 -iquote . -iquote 
/home/oceanfish81/Desktop/qemu -iquote /home/oceanfish81/Desktop/qemu/accel/tcg 
-iquote /home/oceanfish81/Desktop/qemu/include -iquote 
/home/oceanfish81/Desktop/qemu/disas/libvixl -pthread -Wno-unused-function 
-fPIC -MD -MQ libqemuutil.a.p/util_qsp.c.o -MF libqemuutil.a.p/util_qsp.c.o.d 
-o libqemuutil.a.p/util_qsp.c.o -c ../util/qsp.c
  In file included from ../util/qsp.c:62:
  In file included from /home/oceanfish81/Desktop/qemu/include/qemu/thread.h:4:
  In file included from 
/home/oceanfish81/Desktop/qemu/include/qemu/processor.h:10:
  /home/oceanfish81/Desktop/qemu/include/qemu/atomic.h:495:5: error: misaligned 
atomic operation may incur significant performance penalty 
[-Werror,-Watomic-alignment]
      qatomic_set__nocheck(ptr, val);
      ^
  /home/oceanfish81/Desktop/qemu/include/qemu/atomic.h:138:5: note: expanded 
from macro 'qatomic_set__nocheck'
      __atomic_store_n(ptr, i, __ATOMIC_RELAXED)
      ^
  /home/oceanfish81/Desktop/qemu/include/qemu/atomic.h:485:12: error: 
misaligned atomic operation may incur significant performance penalty 
[-Werror,-Watomic-alignment]
      return qatomic_read__nocheck(ptr);
             ^
  /home/oceanfish81/Desktop/qemu/include/qemu/atomic.h:129:5: note: expanded 
from macro 'qatomic_read__nocheck'
      __atomic_load_n(ptr, __ATOMIC_RELAXED)
      ^
  2 errors generated.
  ninja: build stopped: subcommand failed.

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