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  1. Swift
  2. SR-14796

The new swift-driver doesn't pass the '-sdk /' flag correctly to the ClangImporter -sysroot



    • Type: Bug
    • Status: Resolved
    • Priority: Medium
    • Resolution: Done
    • Component/s: Compiler
    • Labels:
    • Environment:

      Fedora Core 33 x86_64


      I came across this bug when trying to build the trunk standalone stdlib with the latest official trunk snapshot build for centos8 on Fedora x86_64. It fails because it passes in -sdk / -resource-dirĀ build/Ninja-Release/swift-linux-x86_64/lib/swift when building the stdlib, which then can't find basic libc headers like sys/types.h.

      I'm able to reproduce by trying to build this simple test file:

      import Foundation

      let fm = FileManager.default
      let path = NSTemporaryDirectory() + "testdir(NSUUID().uuidString)"
      print("creating temporary directory (path)")
      try fm.createDirectory(atPath: path, withIntermediateDirectories: false, attributes: nil)
      try? fm.removeItem(atPath: path)
      print("removed temporary directory (path)")

      If I add the -Xfrontend -dump-clang-diagnostics flag to check the ClangImporter flags, I get

      > ./swift-DEVELOPMENT-SNAPSHOT-2021-06-12-a-centos8/usr/bin/swiftc check.swift -Xfrontend -dump-clang-diagnostics
      'clang' '-fsyntax-only' '-fblocks' '-D_swift_=50500' '-fretain-comments-from-system-headers' '-isystem' '/home/butta/src/swift-DEVELOPMENT-SNAPSHOT-2021-06-12-a-centos8/usr/lib/swift' '-fPIC' '-fmodules' '-Xclang' '-fmodule-feature' '-Xclang' 'swift' '-Werror=non-modular-include-in-framework-module' '-x' 'c' '-std=gnu11' '-fmodule-map-file=/home/butta/src/swift-DEVELOPMENT-SNAPSHOT-2021-06-12-a-centos8/usr/lib/swift/linux/x86_64/glibc.modulemap' '-Xclang' '-nostdsysteminc' '-fmodules-validate-system-headers' '-Xclang' '-fmodule-format=obj' '-fapinotes-modules' '-fapinotes-swift-version=5' '-iapinotes-modules' '/home/butta/src/swift-DEVELOPMENT-SNAPSHOT-2021-06-12-a-centos8/usr/lib/swift/apinotes' '-target' 'x86_64-unknown-linux-gnu' '<swift-imported-modules>' '-resource-dir' '/home/butta/src/swift-DEVELOPMENT-SNAPSHOT-2021-06-12-a-centos8/usr/lib/swift/clang' '-fansi-escape-codes' '-working-directory' '/home/butta/src'

      and that builds fine. If I add the two flags above, it fails:

      > ./swift-DEVELOPMENT-SNAPSHOT-2021-06-12-a-centos8/usr/bin/swiftc check.swift -sdk / -resource-dir swift-DEVELOPMENT-SNAPSHOT-2021-06-12-a-centos8/usr/lib/swift -Xfrontend -dump-clang-diagnostics
      warning: Could not read SDKSettings.json for SDK at: /home/butta/src
      'clang' 'fsyntax-only' '-fblocks' '-D_swift_=50500' '-fretain-comments-from-system-headers' '-isystem' 'swift-DEVELOPMENT-SNAPSHOT-2021-06-12-a-centos8/usr/lib/swift' '-fPIC' '-fmodules' '-Xclang' '-fmodule-feature' '-Xclang' 'swift' '-Werror=non-modular-include-in-framework-module' '-x' 'c' '-std=gnu11' '-fmodule-map-file=swift-DEVELOPMENT-SNAPSHOT-2021-06-12-a-centos8/usr/lib/swift/linux/x86_64/glibc.modulemap' '-sysroot' '/home/butta/src' '-fmodules-validate-system-headers' '-Xclang' '-fmodule-format=obj' '-fapinotes-modules' '-fapinotes-swift-version=5' '-iapinotes-modules' 'swift-DEVELOPMENT-SNAPSHOT-2021-06-12-a-centos8/usr/lib/swift/apinotes' '-target' 'x86_64-unknown-linux-gnu' '<swift-imported-modules>' '-resource-dir' 'swift-DEVELOPMENT-SNAPSHOT-2021-06-12-a-centos8/usr/lib/swift/clang' '-fansi-escape-codes' '-working-directory' '/home/butta/src'
      While building module 'CoreFoundation':
      In file included from <module-includes>:1:
      /home/butta/src/swift-DEVELOPMENT-SNAPSHOT-2021-06-12-a-centos8/usr/lib/swift/CoreFoundation/CoreFoundation.h:25:10: fatal error: 'sys/types.h' file not found

      This same failing command works fine when run with the latest official build of the Swift 5.4.1 toolchain for centos8, but fails with the latest official Swift 5.5 snapshot build too. Comparing the working 5.4.1 command, I see that it is correctly passing -sysroot / to the ClangImporter whereas the trunk and 5.5 snapshot builds incorrectly pass the working directory, ie -sysroot /home/butta/src above.

      What gets even stranger is that I tried building the exact same tag from source on Fedora and I could not reproduce the problem, implying this is an issue with how the official builds are produced on the CI. Maybe something changed recently in the C++ toolchain used to build the Swift compiler on the CI or with how the build is prepared?

      I've put together a pull on the Github Actions CI to demonstrate the same behavior on Ubuntu 20.04, so this is not specific to my Fedora environment. Note how everything works fine with the official Swift 5.4.1 build, that they have pre-installed on the CI.

      Mishal Shah, maybe you know what's going on here.




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