Ldc ImportC preprocessor failure (wrong option syntax) on Windows

Tue Feb 4 10:54:12 UTC 2025

On Tuesday, 4 February 2025 at 10:15:23 UTC, Bastiaan Veelo wrote:
> On Tuesday, 4 February 2025 at 09:57:27 UTC, Richard (Rikki) 
> Andrew Cattermole wrote:
>> On 04/02/2025 10:50 PM, Bastiaan Veelo wrote:
>>> Hi,
>>> 
>>> On my personal machine everything works fine, but our CI 
>>> build machine suffers from this error:
>>> ```
>>> clang-cl.exe: warning: unknown argument ignored in clang-cl 
>>> '- target' (did you mean '--target='?) [-Wunknown-argument]
>>> clang-cl.exe: error: no such file or directory: 
>>> 'x86_64-pc-windows-msvc'
>>> ```
>>> 
>>> I have the impression that options are given as the Microsoft 
>>> preprocessor expects them, but that the clang preprocessor is 
>>> called instead. I think that on my personal machine the 
>>> Microsoft preprocessor is called, which is also what I would 
>>> expect, but I don't know of a way to verify that; the 
>>> workings of ImportC are rather opaque.
>>
>> ldc and dmd have differing behaviors.
>>
>> https://github.com/ldc-developers/ldc/blob/master/driver/cpreprocessor.cpp
>>
>> And yes it prefers clang-cl.
>>
>> Which means this is a bug.
>
> It could be a bug, but locally I use the same version (ldc 
> 1.39.0) and it works fine... Thanks for pointing to the driver 
> source, maybe I can work out what it is doing.

By adding `"dflags-ldc": [ "-v" ],` to `dub.json` I can see that 
indeed locally `cl.exe` is employed, and on the failing machine 
`clang-cl.exe`. Another difference is that the failing machine is 
using slightly newer Windows Kits, but that might be unrelated.

Locally:
```
binary    
C:\Users\bastiaan\AppData\Local\Programs\dlang\ldc2\bin\ldc2.exe
version   1.39.0 (DMD v2.109.1, LLVM 18.1.6)
config    
C:\Users\bastiaan\AppData\Local\Programs\dlang\ldc2\etc\ldc2.conf 
(x86_64-pc-windows-msvc)
predefs   Have_pias_hydrotables Have_pias_shared_use 
Have_pias_nlopt Have_pias_wibu Have_derelict_gl3 Have_gettext 
Have_pias_epcompat Have_pias_version Have_sarcexchange Have_sbin 
Have_derelict_util Have_mofile Have_dxml LDC all D_Version2 
assert D_PreConditions D_PostConditions D_Invariants D_ModuleInfo 
D_Exceptions D_TypeInfo X86_64 D_InlineAsm_X86_64 D_HardFloat 
LittleEndian D_LP64 D_PIC D_AVX D_AVX2 Windows Win64 
CRuntime_Microsoft CppRuntime_Microsoft LDC_LLVM_1801
[...]
Prepending to environment variables:
   INCLUDE += C:\Program Files (x86)\Microsoft Visual 
Studio\2019\Community\VC\Tools\MSVC\14.29.30133\include;C:\Program Files (x86)\Windows Kits\10\include\10.0.22000.0\ucrt;C:\Program Files (x86)\Windows Kits\10\include\10.0.22000.0\shared;C:\Program Files (x86)\Windows Kits\10\include\10.0.22000.0\um;C:\Program Files (x86)\Windows Kits\10\include\10.0.22000.0\winrt;C:\Program Files (x86)\Windows Kits\10\include\10.0.22000.0\cppwinrt
   PATH += C:\Program Files (x86)\Microsoft Visual 
Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\HostX64\x64
MSVC setup took 722 microseconds
C:\Program Files (x86)\Microsoft Visual 
Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\HostX64\x64\cl.exe /nologo /P /PD /Zc:preprocessor protection\wibu\source\wibucm32.c
/FIC:\Users\bastiaan\AppData\Local\Programs\dlang\ldc2\bin\..\import\importc.h /FiC:\Users\bastiaan\AppData\Local\Temp\itmp-ldc-9f6226\wibucm32.i
wibucm32.c
```

On the failing machine:
```
binary    
C:\Users\general\AppData\Local\Programs\dlang\ldc2\bin\ldc2.exe
version   1.39.0 (DMD v2.109.1, LLVM 18.1.6)
config    
C:\Users\general\AppData\Local\Programs\dlang\ldc2\etc\ldc2.conf 
(x86_64-pc-windows-msvc)
predefs   Have_pias_hydrotables Have_pias_shared_use 
Have_pias_nlopt Have_pias_wibu Have_derelict_gl3 Have_gettext 
Have_pias_epcompat Have_pias_version Have_sarcexchange Have_sbin 
Have_derelict_util Have_mofile Have_dxml LDC all D_Version2 
assert D_PreConditions D_PostConditions D_Invariants D_ModuleInfo 
D_Exceptions D_TypeInfo X86_64 D_InlineAsm_X86_64 D_HardFloat 
LittleEndian D_LP64 D_PIC D_AVX D_AVX2 Windows Win64 
CRuntime_Microsoft CppRuntime_Microsoft LDC_LLVM_1801
[...]
Prepending to environment variables:
   INCLUDE += C:\Program Files (x86)\Microsoft Visual 
Studio\2019\Community\VC\Tools\MSVC\14.29.30133\include;C:\Program Files (x86)\Windows Kits\10\include\10.0.22621.0\ucrt;C:\Program Files (x86)\Windows Kits\10\include\10.0.22621.0\shared;C:\Program Files (x86)\Windows Kits\10\include\10.0.22621.0\um;C:\Program Files (x86)\Windows Kits\10\include\10.0.22621.0\winrt;C:\Program Files (x86)\Windows Kits\10\include\10.0.22621.0\cppwinrt
   PATH += C:\Program Files (x86)\Microsoft Visual 
Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\HostX64\x64
MSVC setup took 1184 microseconds
C:\Program Files\LLVM\bin\clang-cl.exe /nologo /P -target 
x86_64-pc-windows-msvc -Xclang -target-feature -Xclang 
-16bit-mode -Xclang -target-feature -Xclang -32bit-mode -Xclang 
-target-feature -Xclang -3dnow -Xclang -target-feature -Xclang 
-3dnowa -Xclang -target-feature -Xclang +64bit -Xclang 
-target-feature -Xclang +64bit-mode -Xclang -target-feature 
-Xclang -adx -Xclang -target-feature -Xclang -aes -Xclang 
-target-feature -Xclang +allow-light-256-bit -Xclang 
-target-feature -Xclang -amx-bf16 -Xclang -target-feature -Xclang 
-amx-complex -Xclang -target-feature -Xclang -amx-fp16 -Xclang 
-target-feature -Xclang -amx-int8 -Xclang -target-feature -Xclang 
-amx-tile -Xclang -target-feature -Xclang +avx -Xclang 
-target-feature -Xclang -avx10.1-256 -Xclang -target-feature 
-Xclang -avx10.1-512 -Xclang -target-feature -Xclang +avx2 
-Xclang -target-feature -Xclang -avx512bf16 -Xclang 
-target-feature -Xclang -avx512bitalg -Xclang -target-feature 
-Xclang -avx512bw -Xclang -target-feature -Xclang -avx512cd 
-Xclang -target-feature -Xclang -avx512dq -Xclang -target-feature 
-Xclang -avx512er -Xclang -target-feature -Xclang -avx512f 
-Xclang -target-feature -Xclang -avx512fp16 -Xclang 
-target-feature -Xclang -avx512ifma -Xclang -target-feature 
-Xclang -avx512pf -Xclang -target-feature -Xclang -avx512vbmi 
-Xclang -target-feature -Xclang -avx512vbmi2 -Xclang 
-target-feature -Xclang -avx512vl -Xclang -target-feature -Xclang 
-avx512vnni -Xclang -target-feature -Xclang -avx512vp2intersect 
-Xclang -target-feature -Xclang -avx512vpopcntdq -Xclang 
-target-feature -Xclang -avxifma -Xclang -target-feature -Xclang 
-avxneconvert -Xclang -target-feature -Xclang -avxvnni -Xclang 
-target-feature -Xclang -avxvnniint16 -Xclang -target-feature 
-Xclang -avxvnniint8 -Xclang -target-feature -Xclang +bmi -Xclang 
-target-feature -Xclang +bmi2 -Xclang -target-feature -Xclang 
-branchfusion -Xclang -target-feature -Xclang -ccmp -Xclang 
-target-feature -Xclang -cf -Xclang -target-feature -Xclang 
-cldemote -Xclang -target-feature -Xclang -clflushopt -Xclang 
-target-feature -Xclang -clwb -Xclang -target-feature -Xclang 
-clzero -Xclang -target-feature -Xclang +cmov -Xclang 
-target-feature -Xclang -cmpccxadd -Xclang -target-feature 
-Xclang +crc32 -Xclang -target-feature -Xclang +cx16 -Xclang 
-target-feature -Xclang +cx8 -Xclang -target-feature -Xclang 
-egpr -Xclang -target-feature -Xclang -enqcmd -Xclang 
-target-feature -Xclang +ermsb -Xclang -target-feature -Xclang 
-evex512 -Xclang -target-feature -Xclang +f16c -Xclang 
-target-feature -Xclang -false-deps-getmant -Xclang 
-target-feature -Xclang +false-deps-lzcnt-tzcnt -Xclang 
-target-feature -Xclang -false-deps-mulc -Xclang -target-feature 
-Xclang -false-deps-mullq -Xclang -target-feature -Xclang 
-false-deps-perm -Xclang -target-feature -Xclang 
+false-deps-popcnt -Xclang -target-feature -Xclang 
-false-deps-range -Xclang -target-feature -Xclang -fast-11bytenop 
-Xclang -target-feature -Xclang +fast-15bytenop -Xclang 
-target-feature -Xclang -fast-7bytenop -Xclang -target-feature 
-Xclang -fast-bextr -Xclang -target-feature -Xclang -fast-gather 
-Xclang -target-feature -Xclang -fast-hops -Xclang 
-target-feature -Xclang -fast-lzcnt -Xclang -target-feature 
-Xclang -fast-movbe -Xclang -target-feature -Xclang 
+fast-scalar-fsqrt -Xclang -target-feature -Xclang 
-fast-scalar-shift-masks -Xclang -target-feature -Xclang 
+fast-shld-rotate -Xclang -target-feature -Xclang 
+fast-variable-crosslane-shuffle -Xclang -target-feature -Xclang 
+fast-variable-perlane-shuffle -Xclang -target-feature -Xclang 
-fast-vector-fsqrt -Xclang -target-feature -Xclang 
-fast-vector-shift-masks -Xclang -target-feature -Xclang 
-faster-shift-than-shuffle -Xclang -target-feature -Xclang +fma 
-Xclang -target-feature -Xclang -fma4 -Xclang -target-feature 
-Xclang +fsgsbase -Xclang -target-feature -Xclang -fsrm -Xclang 
-target-feature -Xclang +fxsr -Xclang -target-feature -Xclang 
-gfni -Xclang -target-feature -Xclang -harden-sls-ijmp -Xclang 
-target-feature -Xclang -harden-sls-ret -Xclang -target-feature 
-Xclang -hreset -Xclang -target-feature -Xclang -idivl-to-divb 
-Xclang -target-feature -Xclang +idivq-to-divl -Xclang 
-target-feature -Xclang +invpcid -Xclang -target-feature -Xclang 
-kl -Xclang -target-feature -Xclang -lea-sp -Xclang 
-target-feature -Xclang -lea-uses-ag -Xclang -target-feature 
-Xclang -lvi-cfi -Xclang -target-feature -Xclang 
-lvi-load-hardening -Xclang -target-feature -Xclang -lwp -Xclang 
-target-feature -Xclang +lzcnt -Xclang -target-feature -Xclang 
+macrofusion -Xclang -target-feature -Xclang +mmx -Xclang 
-target-feature -Xclang +movbe -Xclang -target-feature -Xclang 
-movdir64b -Xclang -target-feature -Xclang -movdiri -Xclang 
-target-feature -Xclang -mwaitx -Xclang -target-feature -Xclang 
-ndd -Xclang -target-feature -Xclang -no-bypass-delay -Xclang 
-target-feature -Xclang -no-bypass-delay-blend -Xclang 
-target-feature -Xclang +no-bypass-delay-mov -Xclang 
-target-feature -Xclang +no-bypass-delay-shuffle -Xclang 
-target-feature -Xclang +nopl -Xclang -target-feature -Xclang 
-pad-short-functions -Xclang -target-feature -Xclang +pclmul 
-Xclang -target-feature -Xclang -pconfig -Xclang -target-feature 
-Xclang -pku -Xclang -target-feature -Xclang +popcnt -Xclang 
-target-feature -Xclang -ppx -Xclang -target-feature -Xclang 
-prefer-128-bit -Xclang -target-feature -Xclang -prefer-256-bit 
-Xclang -target-feature -Xclang -prefer-mask-registers -Xclang 
-target-feature -Xclang -prefer-movmsk-over-vtest -Xclang 
-target-feature -Xclang -prefer-no-gather -Xclang -target-feature 
-Xclang -prefer-no-scatter -Xclang -target-feature -Xclang 
-prefetchi -Xclang -target-feature -Xclang -prefetchwt1 -Xclang 
-target-feature -Xclang -prfchw -Xclang -target-feature -Xclang 
-ptwrite -Xclang -target-feature -Xclang -push2pop2 -Xclang 
-target-feature -Xclang -raoint -Xclang -target-feature -Xclang 
-rdpid -Xclang -target-feature -Xclang -rdpru -Xclang 
-target-feature -Xclang +rdrnd -Xclang -target-feature -Xclang 
-rdseed -Xclang -target-feature -Xclang -retpoline -Xclang 
-target-feature -Xclang -retpoline-external-thunk -Xclang 
-target-feature -Xclang -retpoline-indirect-branches -Xclang 
-target-feature -Xclang -retpoline-indirect-calls -Xclang 
-target-feature -Xclang -rtm -Xclang -target-feature -Xclang 
+sahf -Xclang -target-feature -Xclang -sbb-dep-breaking -Xclang 
-target-feature -Xclang -serialize -Xclang -target-feature 
-Xclang -seses -Xclang -target-feature -Xclang -sgx -Xclang 
-target-feature -Xclang -sha -Xclang -target-feature -Xclang 
-sha512 -Xclang -target-feature -Xclang -shstk -Xclang 
-target-feature -Xclang +slow-3ops-lea -Xclang -target-feature 
-Xclang -slow-incdec -Xclang -target-feature -Xclang -slow-lea 
-Xclang -target-feature -Xclang -slow-pmaddwd -Xclang 
-target-feature -Xclang -slow-pmulld -Xclang -target-feature 
-Xclang -slow-shld -Xclang -target-feature -Xclang 
-slow-two-mem-ops -Xclang -target-feature -Xclang 
-slow-unaligned-mem-16 -Xclang -target-feature -Xclang 
-slow-unaligned-mem-32 -Xclang -target-feature -Xclang -sm3 
-Xclang -target-feature -Xclang -sm4 -Xclang -target-feature 
-Xclang -soft-float -Xclang -target-feature -Xclang +sse -Xclang 
-target-feature -Xclang -sse-unaligned-mem -Xclang 
-target-feature -Xclang +sse2 -Xclang -target-feature -Xclang 
+sse3 -Xclang -target-feature -Xclang +sse4.1 -Xclang 
-target-feature -Xclang +sse4.2 -Xclang -target-feature -Xclang 
-sse4a -Xclang -target-feature -Xclang +ssse3 -Xclang 
-target-feature -Xclang -tagged-globals -Xclang -target-feature 
-Xclang -tbm -Xclang -target-feature -Xclang -tsxldtrk -Xclang 
-target-feature -Xclang -tuning-fast-imm-vector-shift -Xclang 
-target-feature -Xclang -uintr -Xclang -target-feature -Xclang 
-use-glm-div-sqrt-costs -Xclang -target-feature -Xclang 
-use-slm-arith-costs -Xclang -target-feature -Xclang -usermsr 
-Xclang -target-feature -Xclang -vaes -Xclang -target-feature 
-Xclang -vpclmulqdq -Xclang -target-feature -Xclang +vzeroupper 
-Xclang -target-feature -Xclang -waitpkg -Xclang -target-feature 
-Xclang -wbnoinvd -Xclang -target-feature -Xclang -widekl -Xclang 
-target-feature -Xclang +x87 -Xclang -target-feature -Xclang -xop 
-Xclang -target-feature -Xclang +xsave -Xclang -target-feature 
-Xclang -xsavec -Xclang -target-feature -Xclang +xsaveopt -Xclang 
-target-feature -Xclang -xsaves -Xclang -dD 
-Wno-builtin-macro-redefined protection\wibu\source\wibucm32.c 
/FIC:\Users\general\AppData\Local\Programs\dlang\ldc2\bin\..\import\importc.h /FiC:\Users\general\AppData\Local\Temp\itmp-ldc-b2ae43\wibucm32.i
clang-cl.exe: warning: unknown argument ignored in clang-cl 
'-target' (did you mean '--target='?) [-Wunknown-argument]
clang-cl.exe: error: no such file or directory: 
'x86_64-pc-windows-msvc'
protection\wibu\source\sentinel.d(64,8): Error: C:\Program 
Files\LLVM\bin\clang-cl.exe failed with status: 1
protection\wibu\source\sentinel.d(64,8):        C preprocessor 
failed for file 'protection\wibu\source\wibucm32.c'
```

So while the invocation of clang-cl may be buggy, if I can make 
LDC on the CI machine to select Microsoft cl instead, I would be 
good.

-- Bastiaan.