[kbuild-all] Re: [PATCH v2] Makefile: Improve compressed debug info support detection

On Thu, Jun 11, 2020 at 3:03 PM Arvind Sankar <nivedita(a)alum.mit.edu&gt; wrote: > > Commit > 10e68b02c861 ("Makefile: support compressed debug info") > added support for compressed debug sections. > > Support is detected by checking > - does the compiler support -gz=zlib > - does the assembler support --compressed-debug-sections=zlib > - does the linker support --compressed-debug-sections=zlib > > However, the gcc driver's support for this option is somewhat > convoluted. The driver's builtin specs are set based on the version of > binutils that it was configured with. It reports an error if the > configure-time linker/assembler (i.e., not necessarily the actual > assembler that will be run) do not support the option, but only if the > assembler (or linker) is actually invoked when -gz=zlib is passed. > > The cc-option check in scripts/Kconfig.include does not invoke the > assembler, so the gcc driver reports success even if it does not support > the option being passed to the assembler. > > Because the as-option check passes the option directly to the assembler > via -Wa,--compressed-debug-sections=zlib, the gcc driver does not see > this option and will never report an error. Thanks for expanding on the failure. Reviewed-by: Nick Desaulniers <ndesaulniers(a)google.com&gt;