With PicoLibC the SCA `CodeChecker`/`clang-tidy` fails for target `efr32bg22_brd4184a`.

[kmeinhar]

Describe the bug
With the step to set PicoLibC as default LibC the SCA CodeChecker fails for target efr32bg22_brd4184a.
clang-tidy fails with error error: unknown argument: '-fno-printf-return-value' [clang-diagnostic-error].
This flag is not supported by Clang and is removed when compiling with Clang: https://github.com/zephyrproject-rtos/zephyr/blob/main/cmake/compiler/clang/compiler_flags.cmake#L11

CodeChecker starts clang-tidy with options in ${CMAKE_BINARY_DIR}/compile_commands.json.
It includes the GCC specific flag -fno-printf-return-value.

To Reproduce

CodeChecker and clang-tidy succeed with:

• west build -b efr32bg22_brd4184a -d build_hello_world zephyr/samples/hello_world -p -- -DZEPHYR_SCA_VARIANT=codechecker -DCONFIG_MINIMAL_LIBC=y

CodeChecker and clang-tidy fail with:

• west build -b efr32bg22_brd4184a -d build_hello_world zephyr/samples/hello_world -p -- -DZEPHYR_SCA_VARIANT=codechecker -DCONFIG_PICOLIBC=y

Expected behavior
clang-tidy is called without flag -fno-printf-return-value.

Logs and console output

[ERROR 2023-09-05 11:10] -                                                                                                                                                         
clang-15: error: unknown argument: '-fno-printf-return-value'                                                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                                                                                                                      
[ERROR 2023-09-05 11:10] - Analyzing rb.c with clangsa  failed!                                                                                                                                                                                                                                                                                                       
[ERROR 2023-09-05 11:10] -                                                                                                                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                                                                                                                      
[ERROR 2023-09-05 11:10] -                                                                                                                                                                                                                                                                                                                                            
clang-15: error: unknown argument: '-fno-printf-return-value'                                                                                                                                                                                                                                                                                                         
                                                                                                                                                                                   
[ERROR 2023-09-05 11:10] - Analyzing main.c with clangsa  failed!                                                                                                                                                                                                                                                                                                     
[ERROR 2023-09-05 11:10] -                                                                                                                                                         
                                                                                                                                                                                   
[ERROR 2023-09-05 11:10] -                                                                                                                                                         
clang-15: error: unknown argument: '-fno-printf-return-value'                                                                                                                                                                                                                                                                                                         
                                                                                                                                                                                   
[ERROR 2023-09-05 11:10] - Analyzing printk.c with clangsa  failed!                                                                                                                                                                                                                                                                                                   
[ERROR 2023-09-05 11:10] -                                                                                                                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                                                                                                                      
[ERROR 2023-09-05 11:10] -                                                                                                                                                                                                                                                                                                                                            
clang-15: error: unknown argument: '-fno-printf-return-value'                                                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                                                                                                                      
[ERROR 2023-09-05 11:10] - Analyzing hex.c with clangsa  failed!                                                                                                                                                                                                                                                                                                      
[ERROR 2023-09-05 11:10] - Analyzing sem.c with clangsa  failed!                                                                                                                                                                                                                                                                                                      
[ERROR 2023-09-05 11:10] -                                                                                                                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                                                                                                                      
[ERROR 2023-09-05 11:10] -                                                                                                                                                                                                                                                                                                                                            
clang-15: error: unknown argument: '-fno-printf-return-value'                                                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                                                                                                                      
[ERROR 2023-09-05 11:10] -                                                                                                                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                                                                                                                      
[ERROR 2023-09-05 11:10] -                                                                                                                                                                                                                                                                                                                                            
clang-15: error: unknown argument: '-fno-printf-return-value'                                                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                                                                                                                      
[ERROR 2023-09-05 11:10] - Analyzing fdtable.c with clangsa  failed!                                                                                                                                                                                                                                                                                                  
[ERROR 2023-09-05 11:10] -                                                                                                                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                                                                                                                      
[ERROR 2023-09-05 11:10] -                                                                                                                                                                                                                                                                                                                                            
clang-15: error: unknown argument: '-fno-printf-return-value'                                                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                                                                                                                      
[ERROR 2023-09-05 11:10] - Analyzing dec.c with clangsa  failed!                                                                                                                                                                                                                                                                                                      
[ERROR 2023-09-05 11:10] - Analyzing heap.c with clangsa  failed!                                                                                                                                                                                                                                                                                                     
[ERROR 2023-09-05 11:10] -                                                                                                                                                                                                                                                                                                                                            
                                                                                                                                                                                   
[ERROR 2023-09-05 11:10] -                                                                                                                                                                                                                                                                                                                                            
                                                                                                                                                                                   
[ERROR 2023-09-05 11:10] -                                                                                                                                                                                                                                                                                                                                            
clang-15: error: unknown argument: '-fno-printf-return-value'                                                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                                                                                                                      
[ERROR 2023-09-05 11:10] -                                                                                                                                                         
clang-15: error: unknown argument: '-fno-printf-return-value'                                                                                                                                                                                                                                                                                                         

Additional context

Related to #54345

clang-tidy has the flag --extra-arg=<string>. But as far as I can tell this does not make it possible to remove compiler flags imported from compile_commands.json.

[keith-packard]

I'm not sure how this can be fixed -- these clang-based code analysis tools are not compatible with the gcc command line generated in this configuration. I hacked up a change to disable the -fno-printf-return-value flag which only uncovered a larger issue that the --specs=picolibc.specs option, which is responsible for setting the correct include path to locate the picolibc headers instead of the newlib headers, was not handled leading to numerous failures.

I didn't see anything in the Zephyr tree which appears to try and paper over the difference between the gcc toolchain and the clang analysis tools? Is this really the first instance where the incompatibilities in command lines has popped up?

[fabiobaltieri]

cc @pdgendt

[github-actions]

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[github-actions]

This issue has been marked as stale because it has been open (more than) 60 days with no activity. Remove the stale label or add a comment saying that you would like to have the label removed otherwise this issue will automatically be closed in 14 days. Note, that you can always re-open a closed issue at any time.

[matthiasbreier]

I suppose we experience the same or similar issue. I am trying to establish CodeChecker in our CI/CD pipeline (alas for another target) and encountered this and a similar problem (flag "-fno-freestanding" is also not recognized by clang). Unfortunately switching lo LLVM as toolchain does not work as the compilation fails for various reasons.

[pdgendt]

@matthiasbreier

Probably not a proper solution, but I use clangd as an LSP server with the following config:

# .config/clangd/config.yaml

CompileFlags:
  Add: -Wno-unknown-warning-option
  Remove: [-m*, -f*]