Skip to main content

Browse the archive

https://github.com/torvalds/linux
23 October 2021, 00:29:24 UTC
Revision 78a5255ffb6a1af189a83e493d916ba1c54d8c75 authored by Linus Torvalds on 09 May 2020, 20:57:10 UTC, committed by Linus Torvalds on 09 May 2020, 20:57:10 UTC 
Stop the ad-hoc games with -Wno-maybe-initialized
 
We have some rather random rules about when we accept the
"maybe-initialized" warnings, and when we don't.

For example, we consider it unreliable for gcc versions < 4.9, but also
if -O3 is enabled, or if optimizing for size.  And then various kernel
config options disabled it, because they know that they trigger that
warning by confusing gcc sufficiently (ie PROFILE_ALL_BRANCHES).

And now gcc-10 seems to be introducing a lot of those warnings too, so
it falls under the same heading as 4.9 did.

At the same time, we have a very straightforward way to _enable_ that
warning when wanted: use "W=2" to enable more warnings.

So stop playing these ad-hoc games, and just disable that warning by
default, with the known and straight-forward "if you want to work on the
extra compiler warnings, use W=123".

Would it be great to have code that is always so obvious that it never
confuses the compiler whether a variable is used initialized or not?
Yes, it would.  In a perfect world, the compilers would be smarter, and
our source code would be simpler.

That's currently not the world we live in, though.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 1d3962a
Raw File
Tip revision: 78a5255ffb6a1af189a83e493d916ba1c54d8c75 authored by Linus Torvalds on 09 May 2020, 20:57:10 UTC
Stop the ad-hoc games with -Wno-maybe-initialized
Tip revision: 78a5255
Kbuild 
# SPDX-License-Identifier: GPL-2.0
#
# Kbuild for top-level directory of the kernel

#####
# Generate bounds.h

bounds-file := include/generated/bounds.h

always-y := $(bounds-file)
targets := kernel/bounds.s

$(bounds-file): kernel/bounds.s FORCE
	$(call filechk,offsets,__LINUX_BOUNDS_H__)

#####
# Generate timeconst.h

timeconst-file := include/generated/timeconst.h

filechk_gentimeconst = echo $(CONFIG_HZ) | bc -q $<

$(timeconst-file): kernel/time/timeconst.bc FORCE
	$(call filechk,gentimeconst)

#####
# Generate asm-offsets.h

offsets-file := include/generated/asm-offsets.h

always-y += $(offsets-file)
targets += arch/$(SRCARCH)/kernel/asm-offsets.s

arch/$(SRCARCH)/kernel/asm-offsets.s: $(timeconst-file) $(bounds-file)

$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s FORCE
	$(call filechk,offsets,__ASM_OFFSETS_H__)

#####
# Check for missing system calls

always-y += missing-syscalls

quiet_cmd_syscalls = CALL    $<
      cmd_syscalls = $(CONFIG_SHELL) $< $(CC) $(c_flags) $(missing_syscalls_flags)

missing-syscalls: scripts/checksyscalls.sh $(offsets-file) FORCE
	$(call cmd,syscalls)

#####
# Check atomic headers are up-to-date

always-y += old-atomics

quiet_cmd_atomics = CALL    $<
      cmd_atomics = $(CONFIG_SHELL) $<

old-atomics: scripts/atomic/check-atomics.sh FORCE
	$(call cmd,atomics)
back to top