missing build-id everywhere

[vtjnash]

The linker is supposed to set a build-id section, as many tools may expect that information to exist to function properly. Therefore, most distros provide this info by default in the compiler. Why is that section missing from all libraries produced here?

Tried:

$ readelf -n usr/lib/libLLVM-19jl.so 

Expected:

Displaying notes found in: .note.gnu.build-id
  Owner                Data size        Description
  GNU                  0x00000014       NT_GNU_BUILD_ID (unique build ID bitstring)
    Build ID: 45faaa1f2e6e832cf7ffa21199c8b51012ba8daa

Got:
nothing

(might be related to JuliaPackaging/BinaryBuilder.jl#1272)

[giordano]

I don't think we do much for this not to happen. Do we need to configure GCC with --enable-linker-build-id?

[giordano]

I don't see much with Clang either:

sandbox:${WORKSPACE} # echo 'int main() { return 0; }' | gcc -x c - -o gcc.out
sandbox:${WORKSPACE} # readelf -n gcc.out

Displaying notes found at file offset 0x0000021c with length 0x00000020:
  Owner                 Data size	Description
  GNU                  0x00000010	NT_GNU_ABI_TAG (ABI version tag)
    OS: Linux, ABI: 2.4.0
sandbox:${WORKSPACE} # echo 'int main() { return 0; }' | clang -x c - -o clang.out
sandbox:${WORKSPACE} # readelf -n clang.out

Displaying notes found at file offset 0x00000254 with length 0x00000020:
  Owner                 Data size	Description
  GNU                  0x00000010	NT_GNU_ABI_TAG (ABI version tag)
    OS: Linux, ABI: 2.4.0

[Zentrik]

As far as I can tell, to enable build id's by default in the compiler gcc should be configured with --enable-linker-build-id and clang DENABLE_LINKER_BUILD_ID per https://releases.llvm.org/3.9.0/tools/clang/docs/ReleaseNotes.html#major-new-features.
Or just pass -Wl,--build-id into the compiler flags.