On Tue, Feb 11, 2020 at 05:15:39PM -0700, Stephen Warren wrote: > On 2/11/20 3:06 PM, Tom Rini wrote: > > On Tue, Feb 11, 2020 at 03:02:12PM -0700, Stephen Warren wrote: > > > On 2/11/20 11:27 AM, Tom Rini wrote: > > > > On Tue, Feb 11, 2020 at 11:20:36AM -0700, Simon Glass wrote: > > > > > Hi Tom, > > > > > > > > > > On Sat, 8 Feb 2020 at 07:51, Simon Glass <[email protected]> wrote: > > > > > > > > > > > > Hi Stephen, > > > > > > > > > > > > On Thu, 6 Feb 2020 at 15:38, Simon Glass <[email protected]> wrote: > > > > > > > > > > > > > > Hi Stephen, > > > > > > > > > > > > > > On Thu, 6 Feb 2020 at 15:32, Stephen Warren > > > > > > > <[email protected]> wrote: > > > > > > > > > > > > > > > > On 2/6/20 2:55 PM, Simon Glass wrote: > > > > > > > > > Hi Tom, > > > > > > > > > > > > > > > > > > This cannot be pulled yet since we need to update gitlab's > > > > > > > > > docker > > > > > > > > > image to include SDL2. But gitlab seems to be having various > > > > > > > > > problems > > > > > > > > > this week and today i won't work at all: ... > > > > > > > > > > > > > > > > I see the following build error in u-boot-dm/master via Jenkins: > > > > > > > > > > > > > > > > > drivers/misc/p2sb_emul.c: In function > > > > > > > > > ‘sandbox_p2sb_emul_map_physmem’: > > > > > > > > > drivers/misc/p2sb_emul.c:237:6: warning: ‘child’ may be used > > > > > > > > > uninitialized in this function [-Wmaybe-uninitialized] > > > > > > > > > ret = axi_read(child, offset, priv->regs, AXI_SIZE_32); > > > > > > > > > ^ > > > > > > > > > CC common > > > > > > > > > > > > > > Hmmm that's odd. I don't see that, but there are so many > > > > > > > device-tree > > > > > > > and libfdt warnings at present I may have missed it. Will take a > > > > > > > look. > > > > > > > > > > > > That doesn't happen with my gcc 7.3 toolchain. I'll send a patch to > > > > > > set child to NULL at the start, but a look at the code shows that it > > > > > > is correct. > > > > > > > > > > > > Also this is in master and was not introduced by this series. > > > > > > > > > > A fix for this is going in via the x86 tree. > > > > > > > > > > Tom, is there anything else you need from me for this pull request? > > > > > > > > Testing it now, thanks. > > > > > > Now that this has been merged, the build break has come along with it. Is > > > there any chance of picking up the fix from the x86 tree quickly? > > > > I thought we agreed that it seemed like a compiler problem for throwing > > up a false-positive? But are you unable to move up to something a bit > > newer? Thanks! > > It might be possible to upgrade the compiler yet again. I'd rather not keep > changing compilers all the time, which entails extra disk space etc. It's > trivial to solve this issue (a patch has already been posted). I don't think > forcing everyone to change compilers just because some easily-fixable > warning appears is a good idea. > > The code structure in question legitimately warns; it's only by analysis of > additional possibly-inlined functions that happen to be in the same source > file that the compiler could tell if the warning is false. If those called > functions just happened to be implemented in a different source file, the > same warning would be 100% legitimately emitted and probably is even with > newer compilers, and the same fix would need to be applied. I'm not sure I'd > go so far as to call this a compiler bug.
So, we enforce using gcc-6.0 or newer (in reality 6.1, there is no 6.0 release). That's 4 years old this April. In CI, we use gcc 7.3 (which is 2 years old now) and have accepted that if you aren't using at least that version some platforms may not optimize-for-size sufficiently. The flip side of all of this is the problems we keep getting reported and fixes for using gcc-9.x which we can't easily globally switch to, unfortunately. For a one compiler to use everywhere I would suggest the 7.3 that buildman fetches from kernel.org and has for a long while. That said, since Bin is the one who was unhappy with the warning-fix to start with but has since taken a patch for it, I'm not going to overrule him. I expect a PR shortly. -- Tom
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