The weirdest part that as far as I can tell, those are legit bugs.

On my end, I get no warnings whatsoever. The whole build is clean.

On 20 October 2017 at 01:17, Ondřej Hlavatý <[email protected]> wrote:
> OK, this one is just too weird. It seems GCC turns off some heuristics.
> It might be a better option to find out how to turn it back on on lower
> optimization levels.
>
> See this (command taken from make output, optimization moved to the very
> end):
>
> $ cd uspace/drv/bus/pci/pciintel
> $ $CROSS_PREFIX/amd64-unknown-elf/bin/amd64-unknown-elf-gcc  
> -I../../../../lib/c/include -I../../../../lib/c/arch/amd64/include 
> -I../../../../../abi/include -imacros ../../../../../config.h -ffreestanding 
> -fno-builtin -nostdlib -nostdinc -fexec-charset=UTF-8 -finput-charset=UTF-8 
> -D__LE__ -Werror -fno-omit-frame-pointer -ffunction-sections -Wall -Wextra 
> -Wno-clobbered -Wno-unused-parameter -Wmissing-prototypes -std=gnu99 
> -Werror-implicit-function-declaration -Wwrite-strings -pipe 
> -mno-tls-direct-seg-refs -g -I../../../../lib/drv/include -c pci.c -o pci.o 
> -O0
>
> $ $CROSS_PREFIX/amd64-unknown-elf/bin/amd64-unknown-elf-gcc  
> -I../../../../lib/c/include -I../../../../lib/c/arch/amd64/include 
> -I../../../../../abi/include -imacros ../../../../../config.h -ffreestanding 
> -fno-builtin -nostdlib -nostdinc -fexec-charset=UTF-8 -finput-charset=UTF-8 
> -D__LE__ -Werror -fno-omit-frame-pointer -ffunction-sections -Wall -Wextra 
> -Wno-clobbered -Wno-unused-parameter -Wmissing-prototypes -std=gnu99 
> -Werror-implicit-function-declaration -Wwrite-strings -pipe 
> -mno-tls-direct-seg-refs -g -I../../../../lib/drv/include -c pci.c -o pci.o 
> -O1
>
> pci.c: In function 'pci_conf_write':
> pci.c:322:7: error: 'val' may be used uninitialized in this function 
> [-Werror=maybe-uninitialized]
>    val &= ~(0xffU << ((reg & 3) * 8));
>    ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> cc1: all warnings being treated as errors
> $ $CROSS_PREFIX/amd64-unknown-elf/bin/amd64-unknown-elf-gcc  
> -I../../../../lib/c/include -I../../../../lib/c/arch/amd64/include 
> -I../../../../../abi/include -imacros ../../../../../config.h -ffreestanding 
> -fno-builtin -nostdlib -nostdinc -fexec-charset=UTF-8 -finput-charset=UTF-8 
> -D__LE__ -Werror -fno-omit-frame-pointer -ffunction-sections -Wall -Wextra 
> -Wno-clobbered -Wno-unused-parameter -Wmissing-prototypes -std=gnu99 
> -Werror-implicit-function-declaration -Wwrite-strings -pipe 
> -mno-tls-direct-seg-refs -g -I../../../../lib/drv/include -c pci.c -o pci.o 
> -O2
>
> $ $CROSS_PREFIX/amd64-unknown-elf/bin/amd64-unknown-elf-gcc  
> -I../../../../lib/c/include -I../../../../lib/c/arch/amd64/include 
> -I../../../../../abi/include -imacros ../../../../../config.h -ffreestanding 
> -fno-builtin -nostdlib -nostdinc -fexec-charset=UTF-8 -finput-charset=UTF-8 
> -D__LE__ -Werror -fno-omit-frame-pointer -ffunction-sections -Wall -Wextra 
> -Wno-clobbered -Wno-unused-parameter -Wmissing-prototypes -std=gnu99 
> -Werror-implicit-function-declaration -Wwrite-strings -pipe 
> -mno-tls-direct-seg-refs -g -I../../../../lib/drv/include -c pci.c -o pci.o 
> -O3
>
> $ $CROSS_PREFIX/amd64-unknown-elf/bin/amd64-unknown-elf-gcc  
> -I../../../../lib/c/include -I../../../../lib/c/arch/amd64/include 
> -I../../../../../abi/include -imacros ../../../../../config.h -ffreestanding 
> -fno-builtin -nostdlib -nostdinc -fexec-charset=UTF-8 -finput-charset=UTF-8 
> -D__LE__ -Werror -fno-omit-frame-pointer -ffunction-sections -Wall -Wextra 
> -Wno-clobbered -Wno-unused-parameter -Wmissing-prototypes -std=gnu99 
> -Werror-implicit-function-declaration -Wwrite-strings -pipe 
> -mno-tls-direct-seg-refs -g -I../../../../lib/drv/include -c pci.c -o pci.o 
> -Ofast
>
> $ $CROSS_PREFIX/amd64-unknown-elf/bin/amd64-unknown-elf-gcc  
> -I../../../../lib/c/include -I../../../../lib/c/arch/amd64/include 
> -I../../../../../abi/include -imacros ../../../../../config.h -ffreestanding 
> -fno-builtin -nostdlib -nostdinc -fexec-charset=UTF-8 -finput-charset=UTF-8 
> -D__LE__ -Werror -fno-omit-frame-pointer -ffunction-sections -Wall -Wextra 
> -Wno-clobbered -Wno-unused-parameter -Wmissing-prototypes -std=gnu99 
> -Werror-implicit-function-declaration -Wwrite-strings -pipe 
> -mno-tls-direct-seg-refs -g -I../../../../lib/drv/include -c pci.c -o pci.o 
> -Og
>
> pci.c: In function 'pci_conf_write':
> pci.c:322:7: error: 'val' may be used uninitialized in this function 
> [-Werror=maybe-uninitialized]
>    val &= ~(0xffU << ((reg & 3) * 8));
>
> How does this behave on your end?
>
> OH
>
> On 20.10., Jiří Zárevúcky wrote:
>> Weird!
>>
>> Whatever the reason for suspicious silence here, this needs to be fixed.
>> It would be great if you could fix all the warnings you are getting.
>> I'll merge your directive as soon as you have it.
>>
>> Thanks!
>>
>>
>> On 20 October 2017 at 00:20, Ondřej Hlavatý <[email protected]> wrote:
>> > Hi,
>> >
>> > On 19.10., Jiří Zárevúcky wrote:
>> >> Could you elaborate on your setup?
>> >> In particular, do you use the proper cross-compiler, as built using
>> >> toolchain.sh?
>> >
>> > I just installed fresh toolchain, distclean, loaded amd64 defaults and
>> > it happened. Strangely, no warnings are reported with -O2.
>> >
>> >> Also, did you add any additional compiler flags?
>> >
>> > No.
>> >
>> >> Any other changes? Differences from default settings?
>> >
>> > My CROSS_PREFIX is set to dir in my home, not the system default. It
>> > still contains the old toolchain, if that could matter.
>> >
>> > I can't think of any other difference - I don't even use the mainline
>> > checkout while working on xhci.
>> >
>> > OH
>> >
>> >> On 19 October 2017 at 23:40, Ondřej Hlavatý <[email protected]> wrote:
>> >> > Well, it seems that the patch is sufficient only when compiling with
>> >> > -O3. There are a lot of other warnings with -Og. It is probably worth
>> >> > checking them all (possibly with -O0) and fixing/muting them at once.
>> >> >
>> >> > Shall I prepare that?
>> >> >
>> >> > OH
>> >> >
>> >> > On 19.10., Ondra Hlavatý wrote:
>> >> >> Hi all,
>> >> >>
>> >> >> When building current mainline with freshly downloaded toolchain, GCC
>> >> >> 7.1.0 complains about uninitialized variables. First of them is real
>> >> >> (extent.c), the second is not, but it's probably too hard for GCC to
>> >> >> infer.
>> >> >>
>> >> >> Hope you're enjoing the hangout.
>> >> >> Ondra Hlavatý
>> >> >
>> >> >> # Bazaar merge directive format 2 (Bazaar 0.90)
>> >> >> # revision_id: [email protected]
>> >> >> # target_branch: bzr://bzr.helenos.org/mainline/
>> >> >> # testament_sha1: 5343d00f1a73b4b8864f22d5e19dae0f155642cd
>> >> >> # timestamp: 2017-10-19 22:32:34 +0200
>> >> >> # base_revision_id: [email protected]\
>> >> >> #   ndrkufle1quqodg8
>> >> >> #
>> >> >> # Begin patch
>> >> >> === modified file 'uspace/lib/ext4/src/extent.c'
>> >> >> --- uspace/lib/ext4/src/extent.c      2017-05-11 22:07:09 +0000
>> >> >> +++ uspace/lib/ext4/src/extent.c      2017-10-19 20:30:01 +0000
>> >> >> @@ -374,7 +374,7 @@
>> >> >>  int ext4_extent_find_block(ext4_inode_ref_t *inode_ref, uint32_t 
>> >> >> iblock,
>> >> >>      uint32_t *fblock)
>> >> >>  {
>> >> >> -     int rc;
>> >> >> +     int rc = EOK;
>> >> >>       /* Compute bound defined by i-node size */
>> >> >>       uint64_t inode_size =
>> >> >>           ext4_inode_get_size(inode_ref->fs->superblock, 
>> >> >> inode_ref->inode);
>> >> >>
>> >> >> === modified file 'uspace/lib/trackmod/xm.c'
>> >> >> --- uspace/lib/trackmod/xm.c  2014-10-13 17:31:01 +0000
>> >> >> +++ uspace/lib/trackmod/xm.c  2017-10-19 20:30:01 +0000
>> >> >> @@ -288,7 +288,7 @@
>> >> >>       size_t samples;
>> >> >>       size_t instr_size;
>> >> >>       size_t smp_size;
>> >> >> -     size_t smp_hdr_size;
>> >> >> +     size_t smp_hdr_size = 0; /* GCC false alarm on uninitialized */
>> >> >>       ssize_t nread;
>> >> >>       uint8_t ltype;
>> >> >>       trackmod_sample_t *sample;
>> >> >>
>> >> >> # Begin bundle
>> >> >> IyBCYXphYXIgcmV2aXNpb24gYnVuZGxlIHY0CiMKQlpoOTFBWSZTWe8h8/IAAhpfrAAwUPf//17I
>> >> >> lAC////wACAAAgoAUASu73TT2tb13oim3qnhJQgp4m1T0mnqemTVPyp+o9Sfoo9qn6oMh6jQbRBl
>> >> >> GhGJpo0mkPU0A0AAAAABKEBRoyCbRMTT1GjQAAaNGgAaaoCbKNAAGjQaA0AGg0ABJJNGmpgTET0n
>> >> >> oENNI8pkaDQGgNGE5ypN3TW0+0R5HZU5WV9U0/YwFtIdsdkMEzXS50UmZKCSSkkO9B2beBJRTDBB
>> >> >> fETXzctT0PJvAt9bQk9U2VMYCzRs2vIqiyYKGc07734syjxSqw1mJBlQLfHZxNdkb7RszqhmPmzY
>> >> >> L+AbSq+tfe9BqrcUtO2E5Qwx5KxA6RX9ae6s2j4UjvnbmBv+Os3l0ewCIY0HDDAwyEwkwiQgTGkd
>> >> >> KppsRtJPGLIgqLCIPGf4Hd+wIEgyM41hteE6Rc3XdQUl7SltqQ4ZMpgvzIFuLoRaG/aXCyu7yFNq
>> >> >> EKwVI2HxRJwt7cSbcSIBfIUyLiwFZAzLDzWjgByvVSmxSDIDpMtldhLoyjaTq6dDxziYCQpNxcUA
>> >> >> UmyadFcQgM8Z7FprqSghIN+hLJSmhwAVsxF1ZCBRZcsz0BszFVp0V3idomXU0lZuwRhYSLg5lRbT
>> >> >> W7moCZEk9rTjBzCsXpFIt0BT6MD1DVZbXkFyiBWWCnyI54CE77CwZkiS11pEdNQSZ9rUQi5ixt7i
>> >> >> 64JiBZkBTqzC4Jg6TLDgFBZTAPaHSnVODxBYzGXDRyohYsvMQDPpKyV8nSMUH2OMlu5QxVezVOfk
>> >> >> esUalyPYFiraTEDjpdSVy1tQiCiFjKLLJQmGMRRoBdQOLBBJOzsPY1PqDbF8jGdJengFEu5nHMKP
>> >> >> qMpAM6leHOdcNhXTspYxNSYw+10EcO1dTVZMHrtxMY9/O9LSoU4INE9QQOOGNnFjaK3tget7SInN
>> >> >> hFFtpv6sEqdEmXGoi1DjkG8fSdheYa7pWaRVLPn2SIKw5mfxklL99FMvbWEwM8SlnW9XAX9pBdBP
>> >> >> CTGrcaJ5HvLTTl3vWgrAqphfE19OB3lZ2GM3Bh1haia+KDOdA/bncX4a37tDPd+kHOz3Qzsq5NMK
>> >> >> gYRJgaCNcF2Fd9p/ZALzoRjx8yPWbpRh0YHXcS9vdldGpiZcTeSFqvaSEpYsRWHtWOIErYBVHnLk
>> >> >> d50omtMjGwvR7xnjEm9wyrjQiRA7yh1mKrW0TzI8kPquqJX+f63Yw6UYIZBzRHMsvoPiQ8KfhJXo
>> >> >> nm4zwkKW2on1O9iYueSgChEjQpNc3OMLUwz8dK4w8C3g57O0DZ4LcruCthUY2ghjK4cZFH9pIacG
>> >> >> Q4CUEOVNfQ4ir74wNI0u3hBVDuZZf16C7erepZMURR2SnJFC63Kcz2gZfACtU6mGAWXai4Y9Tr0K
>> >> >> F2AcqItgRvWZXPJlttKHEhUeCwpFWVS1yoITAzidBNU/qjVQYOVJFGlA4PZQELCWmQgClk6RXJCP
>> >> >> zSKkCwKKItkBRz3m+QeRAzUxglsnxIgeF29VP4LNstLNyukyIpcZCySKtRjByqAgrj3nia6Dnjyb
>> >> >> MkajQmgcewDuAbNsVYiePp6YwfxdyRThQkO8h8/I
>> >> >
>> >> >> _______________________________________________
>> >> >> HelenOS-devel mailing list
>> >> >> [email protected]
>> >> >> http://lists.modry.cz/listinfo/helenos-devel
>> >> >
>> >> >
>> >> > _______________________________________________
>> >> > HelenOS-devel mailing list
>> >> > [email protected]
>> >> > http://lists.modry.cz/listinfo/helenos-devel
>> >>
>> >> _______________________________________________
>> >> HelenOS-devel mailing list
>> >> [email protected]
>> >> http://lists.modry.cz/listinfo/helenos-devel
>> >
>> > _______________________________________________
>> > HelenOS-devel mailing list
>> > [email protected]
>> > http://lists.modry.cz/listinfo/helenos-devel
>>
>> _______________________________________________
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>
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