can't build wdm/kmdf/umdf clean template.

[mtb (mtb0x1)]

Hello,

After creating a sample project with cargo wdk new --... and cargo wdk build, I get a bunch of error like below.

error[E0080]: attempt to compute `1_usize - 352_usize`, which would overflow
   --> D:\wdriver\kmdf_driver\target\debug\build\wdk-sys-22a289287a10812e\out/types.rs:302:7
    |
302 |     ][::core::mem::size_of::<threadlocaleinfostruct>() - 352usize];
    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ evaluation of `types::bindings::_` failed here

error[E0080]: attempt to compute `1_usize - 12_usize`, which would overflow
    --> D:\wdriver\kmdf_driver\target\debug\build\wdk-sys-22a289287a10812e\out/types.rs:3093:7
     |
3093 |     ][::core::mem::size_of::<_SECURITY_QUALITY_OF_SERVICE>() - 12usize];
     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ evaluation of `types::bindings::_` failed here

error[E0080]: attempt to compute `1_usize - 64_usize`, which would overflow
     --> D:\wdriver\kmdf_driver\target\debug\build\wdk-sys-22a289287a10812e\out/types.rs:14215:23
      |
14215 |     ["Size of _KDPC"][::core::mem::size_of::<_KDPC>() - 64usize];
      |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ evaluation of `types::bindings::_` failed here

modifying the build.rs of wdk-sys with patch below, let me bypass the issue.
version :

wdk-sys = "0.5.1" 

diff --git a/crates/wdk-sys/build.rs b/crates/wdk-sys/build.rs
index 2a73084..93d577f 100644
--- a/crates/wdk-sys/build.rs
+++ b/crates/wdk-sys/build.rs
@@ -248,6 +248,7 @@ fn generate_types(out_path: &Path, config: &Config) -> Result<(), ConfigError> {
 
     let bindgen_builder = bindgen::Builder::wdk_default(config)?
         .with_codegen_config(CodegenConfig::TYPES)
+            .layout_tests(false)     
         .header_contents("types-input.h", &header_contents);
     trace!(bindgen_builder = ?bindgen_builder);

what would be the right fix in my case ? (toolchain/ setup issue) ? cause I believe if the layout tests are wrong then, the binary produced likely to fail later in runtime.

[Melvin Wang (wmmc88)]

Layout tests failing is definitely not good. It means the bindgen-generated bindings can cause issues with the offending types. We're not seeing this issue on our nightly CI runs, so this might be a toolchain version issue.

1. What version of the WDK are you using? (Currently supported and CI-tested versions are in our matrix)
2. How are you consuming the WDK (eWDK, installed WDK via installer/winget, nuget)?
3. What's the contents of your cargo.lock?

[mtb (mtb0x1)]

1. 10.0.26100
2. WDK installed in 2 steps using installer from official microsoft website.

• https://download.microsoft.com/download/8c20ba92-ce77-4348-a6e8-5c0e021763f6/KIT_BUNDLE_WINDOWSSDK_MEDIACREATION/winsdksetup.exe
• https://download.microsoft.com/download/41fb59c2-1723-45f9-a270-96b73ad58233/KIT_BUNDLE_WDK_MEDIACREATION/wdksetup.exe
• LLVM built locally using commit (362de2213e54d16449487cf87b4ee33a99e41e3d) : 22+ unstable.
• Rust :
  rustc 1.91.1 (ed61e7d7e 2025-11-07)
  binary: rustc
  commit-hash: ed61e7d7e242494fb7057f2657300d9e77bb4fcb
  commit-date: 2025-11-07
  host: x86_64-pc-windows-msvc
  release: 1.91.1
  LLVM version: 21.1.2
• Cmd : Developer Command Prompt for VS 2022 + config below :
  set LLVM_HOME=D:\llvm-project\build\Release
  set PATH=%LLVM_HOME%\bin;%PATH%
  set CC=clang
  set CXX=clang++
  set LIBCLANG_PATH=D:\llvm-project\build\Release\bin
  set WDK_VERSION=10.0.26100.0
  set WDK_PATH="C:\Program Files (x86)\Windows Kits\10"

3. Cargo.lock.txt

[Melvin Wang (wmmc88)]

We've been doing some testing and it looks like there's an issue somewhere in ToT llvm. We are unable to repro with latest released LLVM(21.1.2). See #593.

Krishna Kumar Thokala (@krishnakumar4a4) says he was able to repro with ToT LLVM. So it seems like there's something in LLVM that has broken layout parsing of certain types...

[mtb (mtb0x1)]

I will switch to llvm 21, and as for llvm 22 I will wait for release version.