clangd assumes compiler target is 'x86_64-pc-windows-msvc' for .cpp files

[jostlowe]

Hi!

I have set up a project for the STM32H523RET6 using the following setup:

CubeMX: 6.15.0

STM32 vscode extension: 3.5.1

The project is configured to use starm-clang and starm-clang++ and the STARM_PICOLIBC toolchain

I have created a .cpp file () that i added to my build and updated my CMakeLists.txt with the following:

# Setup compiler settings
set(CMAKE_CXX_STANDARD 23)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_EXTENSIONS ON)

...

enable_language(C CXX ASM)

...

# Add sources to executable
target_sources(${CMAKE_PROJECT_NAME} PRIVATE
    Core/Src/myclass.cpp
    # Add user sources here
)

When building the project, it compiles fine, but clangd reports the following problem:

nsupported option '-mcpu=' for target 'x86_64-pc-windows-msvc'clang(drv_unsupported_opt_for_target)
Unsupported option '-mfpu=' for target 'x86_64-pc-windows-msvc'clang(drv_unsupported_opt_for_target)
Unsupported option '-mfloat-abi=' for target 'x86_64-pc-windows-msvc'clang(drv_unsupported_opt_for_target)

Is this a known issue?

For reference (or anyone having a similar issue) i managed to temporarily fix the issue by explicitly setting the target for clangd by changing the .clangd file from

CompileFlags:
  Add:
    - '-ferror-limit=0'
    - '-Wno-implicit-int'
  CompilationDatabase: build/Debug
Diagnostics:
  Suppress:
    - unused-includes
    - unknown_typename
    - unknown_typename_suggest
    - typename_requires_specqual

to

CompileFlags:
  Add:
    - '-ferror-limit=0'
    - '-Wno-implicit-int'
    - '-target'
    - 'thumbv8m.main-st-none-eabihf'
    - '-mfpu=fpv4-sp-d16'
    - '-fno-exceptions'
    - '-fno-rtti'
  CompilationDatabase: build/Debug
Diagnostics:
  Suppress:
    - unused-includes
    - unknown_typename
    - unknown_typename_suggest
    - typename_requires_specqual

[FluxPower42]

Hi @vincent_grenet 

thanks for the update.
I can confirm that the --query-driver entry starm-clang++.exe is no longer removed.

Unfortunately, however, I am (still) experiencing the following issue:
The clangd is NOT using the correct paths for the system includes.

I use here the NUCLEO-H753ZI board with STARM_NEWLIB setting. The following paths should be the right:

• C files:
  c:\Users\[user]\AppData\Local\stm32cube\bundles\st-arm-clang\19.1.6+st.9\lib\clang-runtimes\newlib\arm-none-eabi\armv7m_hard_fpv5_d16\include
  
  
• C++ files:
  c:\Users\[user]\AppData\Local\stm32cube\bundles\st-arm-clang\19.1.6+st.9\lib\clang-runtimes\newlib\arm-none-eabi\armv7m_hard_fpv5_d16\include\c++\v1

But if I hover the mouse over the plain C #include “pwd.h”, I see this path:
C:\Users\[user]\AppData\Local\stm32cube\bundles\st-arm-clang\19.1.6+st.9\lib\clang-runtimes\arm-none-eabi\armv4t_exn_rtti\include\pwd.h

Similarly, the path is incorrect when I hovering over the C++ #include <vector>:
C:\Users\[user]\AppData\Local\stm32cube\bundles\st-arm-clang\19.1.6+st.9\lib\clang-runtimes\arm-none-eabi\armv4t_exn_rtti\include\c++\v1\vector

To be absolutely sure that this is NOT the correct path, I can open these headers by clicking the blue Follow link and insert an #error “Test” at the beginning of the file. After this I perform a >CMake: Clean Rebuild , but the build is still error-free. This means: this file is not used for the build but clangd is using this. If I insert now the same #error line into the vector header file in the correct path, the build aborts as expected.

To test this easily, the attached ZIP file contains a very simple project with an application.cpp file.

The following changes/additions have been made:

./nucleo-h753zi-simple.ioc (via STM32CubeMx)
- NUCLEO-H753ZI board file error corrected: LD2 pin changed from PB7 to PE1 (ST: please correct the NUCLEO-H753ZI board file).
- Toolchain/IDE = CMake
- Default compiler/linker = Starm-Clang

./Application
- application.cpp added
- application.hpp added

./Core/Src/main.c
- #include “application.hpp” added to line 24.
- Call appMain(); added to line 95.

./cmake/starm-clang.cmake
- Line 28 set to: set(STARM_TOOLCHAIN_CONFIG “STARM_NEWLIB”)

./CMakeLists.txt
- File application.cpp added to target_sources.
- Directory Application added to target_include_directories.

To use this, you have to generate the files with the STM32CubeMX and open the folder with VSCode (with installed STM32Cube for VSCode extension).


Additional:
It is not clear to me why clangd does not use the correct path.
If I add --log=verbose and "stm32cube-ide-clangd.trace”: “clangd_trace.json” to settings.json,  it is possible to check what information clangd gets.
If I search for "vector" string I get lines with the correct path (in a "message" node):

but also with the wrong path:

@vincent_grenet 
Can you explain me this behaivior and how can I fix this?