"Unexpected error Error: not found: executable invoked as lld-link" on Windows

[tmssngr]

I've unpacked hylo-v-old-0.0.42-windows-x64.tar.zst into a directory, it has following directory structure:

|   BlocksRuntime.dll
|   dispatch.dll
|   Foundation.dll
|   FoundationEssentials.dll
|   FoundationInternationalization.dll
|   hc.exe
|   MSVCP140.dll
|   swiftCore.dll
|   swiftCRT.dll
|   swiftDispatch.dll
|   swiftWinSDK.dll
|   swift_Concurrency.dll
|   swift_RegexParser.dll
|   swift_StringProcessing.dll
|   VCRUNTIME140.dll
|   VCRUNTIME140_1.dll
|   _FoundationICU.dll
|
\---Hylo_StandardLibrary.resources
    +---Lib
    |       pthreadVCE3.lib
    |       readme.md
    |
    \---Sources
        |   Array.hylo
        |   BitArray.hylo
        |   BoundedArray.hylo
        |   DynamicBuffer.hylo
        |   Heap.hylo
        |   LibC.hylo
        |   Pointers+DynamicAllocation.hylo
        |   Print.hylo
        |
        +---Concurrency
        |       Future.hylo
        |       Spawn.hylo
        |
        +---Core
        |   |   Assert.hylo
        |   |   Bitcast.hylo
        |   |   Bool.hylo
        |   |   Collection.hylo
        |   |   CollectionOfOne.hylo
        |   |   Comparable.hylo
        |   |   Copyable.hylo
        |   |   CTypes.hylo
        |   |   Deinitializable.hylo
        |   |   Equatable.hylo
        |   |   ForeignConvertible.hylo
        |   |   Hashable.hylo
        |   |   Hasher.hylo
        |   |   Iterator.hylo
        |   |   Lifetime.hylo
        |   |   Linear.hylo
        |   |   MemoryAddress.hylo
        |   |   MemoryLayout.hylo
        |   |   Movable.hylo
        |   |   MutableCollection.hylo
        |   |   Operators.hylo
        |   |   Optional.hylo
        |   |   Pointer.hylo
        |   |   PointerToBuffer.hylo
        |   |   PointerToMutable.hylo
        |   |   Range.hylo
        |   |   Regular.hylo
        |   |   Runtime.hylo
        |   |   Strideable.hylo
        |   |   String.hylo
        |   |   Void.hylo
        |   |
        |   +---Numbers
        |   |   |   AdditiveArithmetic.hylo
        |   |   |   ExpressibleByFloatLiteral.hylo
        |   |   |   ExpressibleByIntegerLiteral.hylo
        |   |   |   Numeric.hylo
        |   |   |   SignedNumeric.hylo
        |   |   |
        |   |   +---Floats
        |   |   |       Float32.hylo
        |   |   |       Float64.hylo
        |   |   |
        |   |   \---Integers
        |   |           BinaryInteger.hylo
        |   |           FixedWidthInteger.hylo
        |   |           Int.hylo
        |   |           Int32.hylo
        |   |           Int64.hylo
        |   |           Int8.hylo
        |   |           SignedInteger.hylo
        |   |           UInt.hylo
        |   |           UInt32.hylo
        |   |           UInt64.hylo
        |   |           UInt8.hylo
        |   |
        |   \---String
        |           UTF8Array.hylo
        |
        \---LowLevel
            \---Threading
                    OSThread.hylo
                    Pthread.hylo
                    Thread.hylo

When trying to compile my minimal Main.hylo:

public fun main() {
	print("hello")
}

I'm getting following error:

D:\src\hylo>hc --verbose hw/Main.hylo --emit binary -o hello
begin depolymorphization pass.
create LLVM target machine.
create LLVM program.
LLVM mandatory passes.
LLVM processing complete.
Unexpected error

Error: not found: executable invoked as lld-link

It can emit anything from raw-ast to intel-asm, only binary will fail. Is it because Hylo needs something else, e. g. Visual Studio (which I'd like to avoid)?

[daveshenal]

This isn't a Hylo bug, it's a missing dependency that just isn't bundled in the Windows release archive.

What's happening: --emit binary is the only --emit level that actually invokes a linker (everything earlier in the pipeline, like intel-asm, stops before linking). On Windows, Hylo's compiler shells out to lld-link to do that final link step, but the binary tarball you unpacked only contains hc.exe plus the Swift runtime DLLs, no lld-link.exe. That's confirmed by your own directory listing, and by Hylo's own LLVM build repo, which notes its LLVM package includes tools like lld for compiler development, separate from the end-user hc.exe release.

You don't need full Visual Studio, but you do need two things:

1. LLVM itself (for lld-link.exe) - install standalone LLVM for Windows and make sure it's on your PATH. Easiest options:

   winget install LLVM.LLVM
   

   or choco install llvm. This alone does not require Visual Studio.

2. The MSVC import libraries / Windows SDK - lld-link mimics link.exe's interface, but it still needs Microsoft's actual .lib files (kernel32.lib, libcmt.lib, the UCRT libs, etc.) to resolve symbols. Those only ship via Microsoft's "Build Tools for Visual Studio" - the small, IDE-free standalone installer with just the "Desktop development with C++" component checked. This is not the full Visual Studio IDE; you never need to open or use Visual Studio itself, but the Build Tools package is currently the only way to get those libraries on Windows.

Summary: Install LLVM (for lld-link) and the standalone VS Build Tools C++ workload (for the Windows SDK/import libs).... that's the lightest path that avoids the full Visual Studio IDE while still letting hc --emit binary find everything it needs to link.

[tmssngr]

I prefer unpacking over installing. I've unpacked clang+llvm-22.1.8-x86_64-pc-windows-msvc.tar.xz from LLVM bundle and added its bin subdirectory to the PATH. Now the hello world compiles.