Fix syntax of arguments passed on to Clang

[SimplyDanny]

This option appears to be unsupported in clang (now). Builds fail with clang-cl.

FYI: @compnerd

Edit: The option doesn't need to be removed, but the syntax needs to be different. It works with a single argument instead of two separate ones.

[keith]

seems like in upstream clang it was removed in llvm/llvm-project@0628bea and never added back 🤔

[compnerd]

Pretty sure that this option is not unsupported by clang, but it is not part of llvm.org clang and requires the swift.org clang

[keith]

checking that now

[keith]

ok yea added back in apple only swiftlang/llvm-project@3948c4c

[compnerd]

One thing to consider: it is generally no longer needed on Windows if you have a relatively newer toolchain. Do we want to drop this now simply because we can assume that anyone using the bazel rules_swift will be on a new enough toolchain (i.e. Swift 6+)?

[SimplyDanny]

ok yea added back in apple only swiftlang/llvm-project@3948c4c

So does that mean I need to point Bazel to the Clang toolchain that comes bundled with Swift?

[compnerd]

So does that mean I need to point Bazel to the Clang toolchain that comes bundled with Swift?

Yes, the Swift clang toolchain is not a stock clang, it has extensions whihc are required for Swift to function. You should be pointing bazel to the bundled clang.

[SimplyDanny]

So does that mean I need to point Bazel to the Clang toolchain that comes bundled with Swift?

Yes, the Swift clang toolchain is not a stock clang, it has extensions whihc are required for Swift to function. You should be pointing bazel to the bundled clang.

Could rules_swift do that on its own by default?

[keith]

that is the intent behind the forced --repo_env=CC=clang thing, that might not be enough if you have multiple clangs installed though

[SimplyDanny]

Trying with

build:windows \
  --repo_env=BAZEL_LLVM=C:/Software/swift/Toolchains/6.2.1+Asserts/usr \
  --extra_toolchains=@local_config_cc//:cc-toolchain-x64_windows-clang-cl \
  --extra_execution_platforms=//:x64_windows-clang-cl

and

platform(
    name = "x64_windows-clang-cl",
    constraint_values = [
        "@platforms//cpu:x86_64",
        "@platforms//os:windows",
        "@bazel_tools//tools/cpp:clang-cl",
    ],
)

I get the error

ERROR: C:/users/****/_bazel_msd1lo/ituthjzq/external/rules_swift~/tools/worker/BUILD:34:11: Compiling tools/worker/compile_without_worker.cc [for tool] failed: (Exit -2147483645): clang-cl.exe failed: error executing CppCompile command (from target @@rules_swift~//tools/worker:compile_without_worker) C:\Software\swift\Toolchains\6.2.1+Asserts\usr\bin\clang-cl.exe ... (remaining 1 argument skipped)
Assertion failed: Index >= End && "Unexpected parser error.", file C:\Users\swift-ci\jenkins\workspace\swift-6.2-windows-toolchain\llvm-project\llvm\lib\Option\OptTable.cpp, line 559
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: C:\\Software\\swift\\Toolchains\\6.2.1+Asserts\\usr\\bin\\clang-cl.exe @bazel-out/x64_windows-opt-exec-ST-d610928244b0/bin/external/rules_swift~/tools/worker/_objs/compile_without_worker/compile_without_worker.obj.params
Exception Code: 0x80000003
 #0 0x00007ff7ce355795 (C:\Software\swift\Toolchains\6.2.1+Asserts\usr\bin\clang-cl.exe+0x1725795)
 #1 0x00007ff9f4f6e6d5 (C:\WINDOWS\System32\ucrtbase.dll+0x7e6d5)
 #2 0x00007ff9f4f6f6e1 (C:\WINDOWS\System32\ucrtbase.dll+0x7f6e1)
 #3 0x00007ff9f4f7108e (C:\WINDOWS\System32\ucrtbase.dll+0x8108e)
 #4 0x00007ff9f4f712d1 (C:\WINDOWS\System32\ucrtbase.dll+0x812d1)
 #5 0x00007ff7ce22195c (C:\Software\swift\Toolchains\6.2.1+Asserts\usr\bin\clang-cl.exe+0x15f195c)
 #6 0x00007ff7ce21fbf2 (C:\Software\swift\Toolchains\6.2.1+Asserts\usr\bin\clang-cl.exe+0x15efbf2)
 #7 0x00007ff7cedeaff8 (C:\Software\swift\Toolchains\6.2.1+Asserts\usr\bin\clang-cl.exe+0x21baff8)
 #8 0x00007ff7cccd1121 (C:\Software\swift\Toolchains\6.2.1+Asserts\usr\bin\clang-cl.exe+0xa1121)
 #9 0x00007ff7ccce53f6 (C:\Software\swift\Toolchains\6.2.1+Asserts\usr\bin\clang-cl.exe+0xb53f6)
#10 0x00007ff7d17cb514 (C:\Software\swift\Toolchains\6.2.1+Asserts\usr\bin\clang-cl.exe+0x4b9b514)
#11 0x00007ff9f627259d (C:\WINDOWS\System32\KERNEL32.DLL+0x1259d)
#12 0x00007ff9f750af78 (C:\WINDOWS\SYSTEM32\ntdll.dll+0x5af78)

[keith]

i believe this failure is compiler params files not being properly formatted. you can try with --features=-compiler_param_file --host_features=-compiler_param_file

[SimplyDanny]

i believe this failure is compiler params files not being properly formatted. you can try with --features=-compiler_param_file --host_features=-compiler_param_file

With --host_features=-compiler_param_file it compiles without the "fix" in this PR, but fails linking. --features=-archive_param_file makes that work, too, since --feature=windows_quoting_for_param_files (which actually sounds promising) doesn't seem to have any effect.

I'm trying to build https://github.com/apple/swift-argument-parser by the way.

[SimplyDanny]

FYI: I draftet a PR for LLVM with llvm/llvm-project#171214 to make the argument parsing process less sensitive to such subtleties.

@keith: Thanks for merging! Next would be archive_param_file which doesn't quote paths containing spaces properly. Any idea why windows_quoting_for_param_files wouldn't work?

I wonder if this needs fixing in LLVM as well, though.

[keith]

i think that's probably a bug somewhere on the bazel side. looks to me like https://github.com/bazelbuild/rules_cc/blob/a2994c414fafa1acdc2f461edda85d67841f88ec/cc/private/toolchain/windows_cc_toolchain_config.bzl needs to define the windows_quoting_for_param_files feature in order for it to ever be considered enabled:

https://github.com/bazelbuild/rules_cc/blob/a2994c414fafa1acdc2f461edda85d67841f88ec/cc/private/link/finalize_link_action.bzl#L340