Dawn+CLion on Windows

[Shannon Carey]

Hi,

I'm an experienced developer, but I don't know C++ or CMake very well. I recently tried following tutorials like https://developer.chrome.com/docs/web-platform/webgpu/build-app , but despite trying to follow the instructions precisely, had a heck of a time getting it working. As soon as I run my exe, I get console output like: "Process finished with exit code -1073741515 (0xC0000135)". I tried many things, but none of them helped.

It was only when I happened to run the exe from CLion in "debug" mode (not "Debug" release but like, with a debugger attached), that I got a meaningful error message, basically, "webgpu_dawn.dll was not found".

It seems that the instructions assume that the built exe will end up in the same directory as webgpu_dawn.dll. However, instead the built DLL was in "./dawn" relative to the exe, therefore it couldn't be found. After doing some searching, I added this to my CMakeLists.txt which fixes the issue by copying the DLL into the same directory as the exe. I don't know if this is the "best" solution, but it works well enough for me.

add_custom_command(TARGET myapp POST_BUILD
        COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_RUNTIME_DLLS:myapp> $<TARGET_FILE_DIR:myapp>
        COMMAND_EXPAND_LISTS
)

I don't know if my scenario is specific to Windows, CMake, or CLion. But it seems like the build config or the tutorial instructions may need some improvement to produce a reliable outcome. In any case, maybe this will help someone else.

I also tried following the instructions in https://dawn.googlesource.com/dawn/+/HEAD/docs/quickstart-cmake.md but those don't seem to work either. I get:

D:\projects\oss\dawn>cmake --install out/Release --prefix install/Release
-- Install configuration: "Release"
CMake Error at out/Release/src/dawn/native/cmake_install.cmake:51 (file):
  file INSTALL cannot find
  "D:/projects/oss/dawn/out/Release/Release/webgpu_dawn.dll": File exists.
Call Stack (most recent call first):
  out/Release/src/dawn/cmake_install.cmake:62 (include)
  out/Release/cmake_install.cmake:62 (include)

Also, during "cmake --build out/Release" I notice a lot of suspicious looking mentions of "Debug" even though it's supposed to be a Release build. For example:

  SPIRV-Tools-static.vcxproj -> D:\projects\oss\dawn\out\Release\third_party\spirv-tools\source\Debug\SPIRV-Tools.lib
  SPIRV-Tools-opt.vcxproj -> D:\projects\oss\dawn\out\Release\third_party\spirv-tools\source\opt\Debug\SPIRV-Tools-opt.
  lib

....

  webgpu_dawn.vcxproj -> D:\projects\oss\dawn\out\Release\Debug\webgpu_dawn.dll

-Shannon

[Corentin Wallez]

Hey Shannon,

+CC Francois to see if the sample app works with the DAWN_BUILD_MONOLITHIC_LIBRARY=SHARED.

On Wed, Sep 3, 2025 at 5:28 AM Shannon Carey <rehe...@gmail.com> wrote:

Hi,

I'm an experienced developer, but I don't know C++ or CMake very well. I recently tried following tutorials like https://developer.chrome.com/docs/web-platform/webgpu/build-app , but despite trying to follow the instructions precisely, had a heck of a time getting it working. As soon as I run my exe, I get console output like: "Process finished with exit code -1073741515 (0xC0000135)". I tried many things, but none of them helped.

It was only when I happened to run the exe from CLion in "debug" mode (not "Debug" release but like, with a debugger attached), that I got a meaningful error message, basically, "webgpu_dawn.dll was not found".

It seems that the instructions assume that the built exe will end up in the same directory as webgpu_dawn.dll. However, instead the built DLL was in "./dawn" relative to the exe, therefore it couldn't be found. After doing some searching, I added this to my CMakeLists.txt which fixes the issue by copying the DLL into the same directory as the exe. I don't know if this is the "best" solution, but it works well enough for me.

add_custom_command(TARGET myapp POST_BUILD
        COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_RUNTIME_DLLS:myapp> $<TARGET_FILE_DIR:myapp>
        COMMAND_EXPAND_LISTS
)

I don't know if my scenario is specific to Windows, CMake, or CLion. But it seems like the build config or the tutorial instructions may need some improvement to produce a reliable outcome. In any case, maybe this will help someone else.

I'm not sure why CMake / CLion wouldn't put the DLL in the same directory. Maybe it is a build vs. install thing? The windows error code really wasn't very helpful in telling what the actual problem was.

 

I also tried following the instructions in https://dawn.googlesource.com/dawn/+/HEAD/docs/quickstart-cmake.md but those don't seem to work either. I get:

D:\projects\oss\dawn>cmake --install out/Release --prefix install/Release
-- Install configuration: "Release"
CMake Error at out/Release/src/dawn/native/cmake_install.cmake:51 (file):
  file INSTALL cannot find
  "D:/projects/oss/dawn/out/Release/Release/webgpu_dawn.dll": File exists.
Call Stack (most recent call first):
  out/Release/src/dawn/cmake_install.cmake:62 (include)
  out/Release/cmake_install.cmake:62 (include)

That seems like it was because you had a leftover install from a previous build, 

 

Also, during "cmake --build out/Release" I notice a lot of suspicious looking mentions of "Debug" even though it's supposed to be a Release build. For example:

  SPIRV-Tools-static.vcxproj -> D:\projects\oss\dawn\out\Release\third_party\spirv-tools\source\Debug\SPIRV-Tools.lib
  SPIRV-Tools-opt.vcxproj -> D:\projects\oss\dawn\out\Release\third_party\spirv-tools\source\opt\Debug\SPIRV-Tools-opt.
  lib

....

  webgpu_dawn.vcxproj -> D:\projects\oss\dawn\out\Release\Debug\webgpu_dawn.dll

-Shannon

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Cheers,

Corentin 

[François Beaufort]

On Mon, Sep 8, 2025 at 5:15 PM Corentin Wallez <cwa...@google.com> wrote:

Hey Shannon,

+CC Francois to see if the sample app works with the DAWN_BUILD_MONOLITHIC_LIBRARY=SHARED.

I've tried it locally and it works fine with set(DAWN_BUILD_MONOLITHIC_LIBRARY SHARED).
Shall I update https://github.com/beaufortfrancois/webgpu-cross-platform-app/blob/main/CMakeLists.txt?

Note that the default value just switched from OFF to STATIC: https://dawn-review.googlesource.com/c/dawn/+/261115
 

[François Beaufort]

Did this help eventually?