build: Silence [-Wunused-command-line-argument] warnings #21788

pull hebasto wants to merge 1 commits into bitcoin:master from hebasto:210427-clash changing 1 files +1 −1
  1. hebasto commented at 6:42 PM on April 27, 2021: member

    Apple clang version 12.0.5 (clang-1205.0.22.9) that is a part of Xcode 12.5, and is based on LLVM clang 11.1.0, fires spammy warnings:

    clang: warning: argument unused during compilation: '-fstack-clash-protection' [-Wunused-command-line-argument]

    From the https://github.com/apple/llvm-project:

    $ git log --oneline | grep 'stack-clash-protection'
00065d5cbd02 Revert "-fstack-clash-protection: Return an actual error when used on unsupported OS"
4d59c8fdb955 -fstack-clash-protection: Return an actual error when used on unsupported OS
df3bfaa39071 [Driver] Change -fnostack-clash-protection to  -fno-stack-clash-protection
68e07da3e5d5 [clang][PowerPC] Enable -fstack-clash-protection option for ppc64
515bfc66eace [SystemZ] Implement -fstack-clash-protection
e67cbac81211 Support -fstack-clash-protection for x86
454621160066 Revert "Support -fstack-clash-protection for x86"
0fd51a4554f5 Support -fstack-clash-protection for x86
658495e6ecd4 Revert "Support -fstack-clash-protection for x86"
e229017732bc Support -fstack-clash-protection for x86
b03c3d8c6209 Revert "Support -fstack-clash-protection for x86"
4a1a0690ad68 Support -fstack-clash-protection for x86
f6d98429fcdb Revert "Support -fstack-clash-protection for x86"
39f50da2a357 Support -fstack-clash-protection for x86

    I suppose, that Apple clang-1205.0.22.9 ends with on of the "Revert..." commits.

    This PR prevents using of the -fstack-clash-protection flag if it causes warnings.

    System: macOS Big Sur 11.3 (20E232).

  2. hebasto added the label Build system on Apr 27, 2021
  3. hebasto added the label macOS on Apr 27, 2021
  4. MarcoFalke added the label Needs gitian build on Apr 27, 2021
  5. MarcoFalke added the label Needs Guix build on Apr 27, 2021
  6. jarolrod commented at 8:23 PM on April 27, 2021: member

    ACK b9fe3afce6fb7ace72961155fc4df900037335df

    tested on macOS 11.3

    Master

    make -j"$(($(sysctl -n hw.logicalcpu)+1))" 2>&1 > /dev/null | grep -o "fstack-clash-protection" | wc -l

615

    PR

    make -j"$(($(sysctl -n hw.logicalcpu)+1))" 2>&1 > /dev/null | grep -o "fstack-clash-protection" | wc -l

0

    Guix Hashes

    find guix-build-$(git rev-parse --short=12 HEAD)/output/ -type f -print0 | env LC_ALL=C sort -z | xargs -r0 sha256sum

96c151bcd1f1663264f5f630aff70b7c8cdf010ee00048858678a932db8e5ff2  guix-build-b9fe3afce6fb/output/aarch64-linux-gnu/bitcoin-b9fe3afce6fb-aarch64-linux-gnu-debug.tar.gz
4fa8458a775d8d89be675a4c6e02fefb1835b5ae4598012b85b8b43a722a136d  guix-build-b9fe3afce6fb/output/aarch64-linux-gnu/bitcoin-b9fe3afce6fb-aarch64-linux-gnu.tar.gz
aa1b9ce1d73e09e7afd54dde338eefa3b1ab19bcff730ad3e893444bf7660c1a  guix-build-b9fe3afce6fb/output/arm-linux-gnueabihf/bitcoin-b9fe3afce6fb-arm-linux-gnueabihf-debug.tar.gz
660e82039a41c72ce35b39ce0321e28fd863999dc979f303753b7ba71048fac4  guix-build-b9fe3afce6fb/output/arm-linux-gnueabihf/bitcoin-b9fe3afce6fb-arm-linux-gnueabihf.tar.gz
bbb21a4bc22273dc45019db09f6038f9a4006880e9af6318b60f03e02360a55b  guix-build-b9fe3afce6fb/output/dist-archive/bitcoin-b9fe3afce6fb.tar.gz
7424146d4f66cce624844c192b1619430e9722c6d8da32c27a819518213db323  guix-build-b9fe3afce6fb/output/powerpc64-linux-gnu/bitcoin-b9fe3afce6fb-powerpc64-linux-gnu-debug.tar.gz
d959de8ee2f5360473fb3b67e4b235bad9709c9b1167cae04cb7c5e43de60146  guix-build-b9fe3afce6fb/output/powerpc64-linux-gnu/bitcoin-b9fe3afce6fb-powerpc64-linux-gnu.tar.gz
211dc230e3bb50ce492389eab7015f5a305a1bc2bfaa2cecbb7bea294aa13273  guix-build-b9fe3afce6fb/output/powerpc64le-linux-gnu/bitcoin-b9fe3afce6fb-powerpc64le-linux-gnu-debug.tar.gz
3036df123d9aead52f34c8c595759a4ee32598a877ce4b1e3eeec109343c668d  guix-build-b9fe3afce6fb/output/powerpc64le-linux-gnu/bitcoin-b9fe3afce6fb-powerpc64le-linux-gnu.tar.gz
66f90ff528c59cb9a2f8d92d1e8f4a0800bd7f75567878f20f02d4a6192f6070  guix-build-b9fe3afce6fb/output/riscv64-linux-gnu/bitcoin-b9fe3afce6fb-riscv64-linux-gnu-debug.tar.gz
e361b6d7a1809b27d331cd1df02192f785de93b82b99b23421ca77c8a26d4682  guix-build-b9fe3afce6fb/output/riscv64-linux-gnu/bitcoin-b9fe3afce6fb-riscv64-linux-gnu.tar.gz
a2980ec97fc0a64403d8adb82c3cd5014e9b0d2e911e511df8dc1fe09b67cc86  guix-build-b9fe3afce6fb/output/x86_64-apple-darwin18/bitcoin-b9fe3afce6fb-osx-unsigned.dmg
3a56ad51c6824488684a2021b5d952aa1fc38a6d165add1f72d4b3643fc5947b  guix-build-b9fe3afce6fb/output/x86_64-apple-darwin18/bitcoin-b9fe3afce6fb-osx-unsigned.tar.gz
f1feb7fef798ef1c5a3304408df3a1590a62b843d996e7bc5659d45683d677b4  guix-build-b9fe3afce6fb/output/x86_64-apple-darwin18/bitcoin-b9fe3afce6fb-osx64.tar.gz
b0c2a26050869dc4b83fb05765856ab48b4a683026f51b1b3152d265d594bf0e  guix-build-b9fe3afce6fb/output/x86_64-linux-gnu/bitcoin-b9fe3afce6fb-x86_64-linux-gnu-debug.tar.gz
b0cd5c21673d8c97768de7dcd1de2e9bc7b6910ce6e034bccb8223d0430a5722  guix-build-b9fe3afce6fb/output/x86_64-linux-gnu/bitcoin-b9fe3afce6fb-x86_64-linux-gnu.tar.gz
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153dea4cc0bc59e939b7aeaae042450efd784b2225ab81872c1473ac84c70f51  guix-build-b9fe3afce6fb/output/x86_64-w64-mingw32/bitcoin-b9fe3afce6fb-win64-setup-unsigned.exe
598968164f4ba9759b6bcb64609b01c776efb72abb29badd0298a71255fdc167  guix-build-b9fe3afce6fb/output/x86_64-w64-mingw32/bitcoin-b9fe3afce6fb-win64.zip
  7. fanquake removed the label macOS on Apr 28, 2021
  8. fanquake commented at 4:12 AM on April 28, 2021: member

    This change is not macOS specific, so it shouldn't be labelled that way or made to seem that way in the commit message. You're changing how we test for support for a compile flag, which, in this case, is relevant for any OS other than Windows, across both Clang and GCC.

    Regardless of the above. What's the underlying cause of the new warnings? What changed that they've only started happening now?

  9. willcl-ark commented at 11:36 AM on April 28, 2021: member

    ACK b9fe3af

    $ MacOS 11.4 Beta (20F5046g)
$ xcode-select version 2384
$ g++ --version
Configured with: --prefix=/Library/Developer/CommandLineTools/usr --with-gxx-include-dir=/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/c++/4.2.1
Apple clang version 12.0.5 (clang-1205.0.22.9)
Target: x86_64-apple-darwin20.5.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

    I was in fact hitting compile errors before applying this patch on top of master. Now it both compiles and warnings are removed.

    Of note, and I don't want to derail this PR, but I also get about 8000 lines of -Wsuggest-override warnings from various boost packages with the new command line tools 🙄: compile.txt. I will investigate a little further and open a new issue for this though.

  10. hebasto commented at 2:16 PM on April 28, 2021: member

    @willcl-ark

    Thanks for testing!

    Of note, and I don't want to derail this PR, but I also get about 8000 lines of -Wsuggest-override warnings from various boost packages with the new command line tools roll_eyes: compile.txt. I will investigate a little further and open a new issue for this though.

    Probably, you'd want to pass --enable-suppress-external-warnings to your configure script`.

  11. willcl-ark commented at 2:22 PM on April 28, 2021: member

    Thanks @hebasto, that does indeed suppress those warnings.

  12. hebasto renamed this:
    build: Silent unused -fstack-clash-protection warnings on macOS 11.3
    build: Silent [-Wunused-command-line-argument] warnings with Apple clang 12.0.5
    on Apr 28, 2021
  13. hebasto commented at 11:19 PM on April 28, 2021: member

    @fanquake

    This change is not macOS specific, so it shouldn't be labelled that way or made to seem that way in the commit message. You're changing how we test for support for a compile flag, which, in this case, is relevant for any OS other than Windows, across both Clang and GCC.

    Thanks. Understand.

    Regardless of the above. What's the underlying cause of the new warnings? What changed that they've only started happening now?

    I've updated the PR description.

  14. DrahtBot removed the label Needs gitian build on Apr 29, 2021
  15. in configure.ac:897 in b9fe3afce6 outdated 
     893 | @@ -894,7 +894,7 @@ if test x$use_hardening != xno; then
 894 |        dnl See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90458 for more details.
 895 |        ;;
 896 |      *)
 897 | -      AX_CHECK_COMPILE_FLAG([-fstack-clash-protection],[HARDENED_CXXFLAGS="$HARDENED_CXXFLAGS -fstack-clash-protection"])
 898 | +      AX_CHECK_COMPILE_FLAG([-fstack-clash-protection], [HARDENED_CXXFLAGS="$HARDENED_CXXFLAGS -fstack-clash-protection"], [], [$CXXFLAG_WERROR])
    Sjors commented at 5:41 PM on May 5, 2021:

    This could use a comment.

    hebasto commented at 12:25 PM on May 7, 2021:

    I'll add it if any other changes will be requested by reviewers.

    jarolrod commented at 2:56 PM on May 24, 2021:

    Is a comment still required after the update to the commit message on e9f948c?

    hebasto commented at 3:07 PM on May 24, 2021:

    Most of the AX_CHECK_COMPILE_FLAG macros in the configure.ac use the same pattern.

    Could you elaborate which comment will be useful?

  16. Sjors commented at 6:08 PM on May 5, 2021: member

    I can confirm b9fe3af makes the (maddening) warnings go away on macOS 11.3.1

  17. practicalswift commented at 3:31 PM on May 7, 2021: contributor

    cr ACK b9fe3afce6fb7ace72961155fc4df900037335df: patch looks correct @hebasto What do you think about making this change conditional on macOS + Clang to make sure non-macOS platforms and non-Clang users are unaffected?

  18. fjahr commented at 9:36 AM on May 9, 2021: member

    Tested ACK b9fe3afce6fb7ace72961155fc4df900037335df (macOS 11.3.1, clang 12.0.0)

  19. hebasto commented at 6:36 PM on May 9, 2021: member

    @practicalswift

    @hebasto What do you think about making this change conditional on macOS + Clang to make sure non-macOS platforms and non-Clang users are unaffected?

    What if other host/build_os/compiler set will not have the -fstack-clash-protection flag available? Isn't the reason to use the AX_CHECK_COMPILE_FLAG macro to check the availability of a flag?

  20. practicalswift commented at 8:41 PM on May 9, 2021: contributor

    @hebasto What do you think about making this change conditional on macOS + Clang to make sure non-macOS platforms and non-Clang users are unaffected?

    What if other host/build_os/compiler set will not have the -fstack-clash-protection flag available? Isn't the reason to use the AX_CHECK_COMPILE_FLAG macro to check the availability of a flag?

    Sure, the AX_CHECK_COMPILE_FLAG must be there for all platforms :)

    My thinking was that you could keep the AX_CHECK_COMPILE_FLAG check as-is for platforms unaffected by the problem being addressed, and only change it for platforms where we have reason to believe this change might be needed.

    Perhaps doing so is deemed too hacky even for a configure script: IDK TBH :)

    The context being this feedback from fanquake (https://github.com/bitcoin/bitcoin/pull/21788#issuecomment-828129164): "This change is not macOS specific, so it shouldn't be labelled that way or made to seem that way in the commit message. You're changing how we test for support for a compile flag, which, in this case, is relevant for any OS other than Windows, across both Clang and GCC."

  21. jarolrod commented at 10:57 PM on May 9, 2021: member

    @fjahr

    (macOS 11.3.1, clang 12.0.0)

    Did these warnings come up on clang 12.0.0 for you? They shouldn't.

  22. fjahr commented at 9:32 PM on May 10, 2021: member

    @fjahr

    (macOS 11.3.1, clang 12.0.0)

    Did these warnings come up on clang 12.0.0 for you? They shouldn't.

    It appears they do. Why shouldn't they?

    $ clang -v
clang version 12.0.0

    Side-note: my error message is also not exactly the same hebasto's at the moment, it specifies clang-12: instead of just clang:

    clang-12: warning: argument unused during compilation: '-fstack-clash-protection' [-Wunused-command-line-argument]
  23. hebasto commented at 9:40 PM on May 10, 2021: member

    @fjahr

    Which way did you get your clang installation in?

  24. fjahr commented at 11:03 PM on May 10, 2021: member

    @fjahr

    Which way did you get your clang installation in?

    Homebrew

  25. DrahtBot removed the label Needs Guix build on May 13, 2021
  26. laanwj renamed this:
    build: Silent [-Wunused-command-line-argument] warnings with Apple clang 12.0.5
    build: Silence [-Wunused-command-line-argument] warnings with Apple clang 12.0.5
    on May 19, 2021
  27. hebasto commented at 9:25 PM on May 22, 2021: member

    @fanquake @practicalswift

    If you have a chance, let me know how this PR could be improved, please.

  28. fanquake commented at 4:33 AM on May 24, 2021: member

    If you have a chance, let me know how this PR could be improved, please.

    Can you change the commit message, and include an explanation of the change in the commit body. As I mentioned above, the change being made here isn't macOS specific, and the macOS version, 11.3 (currently included in the commit message), is irrelevant. The version of Apple Clang you use is governed by the version of Xcode that is installed, and I could install Xcode 12.5 on any version of macOS 11.0+. So this is not a problem specific to macOS 11.3+, or even to Apple Clang, as compiling using LLVM Clang on macOS produces the same warning output.

    Regardless of that, if i remember correctly I've seen the same warnings when compiling with Clang on *BSDs. Although it looks like support may soon be enabled there, see https://reviews.freebsd.org/D27366. Related discussion in https://reviews.llvm.org/D92100 as well.

    So ideally we have a commit message more like this:

    build: convert warnings into errors when testing for -fstack-clash-protection

When building with Clang, if `-fstack-clash-protection` is used with an unsupported target, it may result in hundreds of `-Wunused-command-line-argument` warnings at compile time. This is currently the case when building for at least Darwin using Apple or LLVM Clang.

Unsupported targets may also include *BSD, however that is changing; see further discussion in https://reviews.llvm.org/D92245 and https://reviews.freebsd.org/D27366. 

Note that this option is already skipped for Windows.
  29. build: Convert warnings into errors when testing for -fstack-clash-protection
    When building with Clang, if `-fstack-clash-protection` is used with an
unsupported target, it may result in hundreds of
`-Wunused-command-line-argument` warnings at compile time. This is
currently the case when building for at least Darwin using Apple or LLVM
Clang.

Unsupported targets may also include *BSD, however that is changing; see
further discussion in https://reviews.llvm.org/D92245 and
https://reviews.freebsd.org/D27366. 

Note that this option is already skipped for Windows.
    e9f948c727
  30. hebasto force-pushed on May 24, 2021
  31. hebasto commented at 5:58 AM on May 24, 2021: member

    @fanquake

    Thanks! Updated.

  32. hebasto renamed this:
    build: Silence [-Wunused-command-line-argument] warnings with Apple clang 12.0.5
    build: Silence [-Wunused-command-line-argument] warnings
    on May 24, 2021
  33. MarcoFalke deleted a comment on May 24, 2021
  34. MarcoFalke deleted a comment on May 24, 2021
  35. MarcoFalke added the label Needs Guix build on May 24, 2021
  36. jarolrod commented at 2:56 PM on May 24, 2021: member

    re-ACK e9f948c72790136656df6056fd9e3698f360e077

    Don't see anything to review between b9fe3af and e9f948c. The only difference is the commit message.

  37. Sjors commented at 3:41 PM on May 24, 2021: member

    tACK e9f948c72790136656df6056fd9e3698f360e077 on macOS 11.3.1

  38. fanquake merged this on May 25, 2021
  39. fanquake closed this on May 25, 2021
  40. hebasto deleted the branch on May 25, 2021
  41. sidhujag referenced this in commit 73b026a806 on May 25, 2021
  42. MarcoFalke removed the label Needs Guix build on May 31, 2021
  43. gwillen referenced this in commit ec1cd3288c on Jun 1, 2022
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  48. DrahtBot locked this on Aug 18, 2022
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