Troubleshooting Last updated Feb 11, 2025

NB: OCaml -verbose flag means only “‘print calls to external commands”; it does not make OCaml itself more verbose. For that you can use the (mostly undocumented) -d flags like -dtypedtree.

bazel build tgt --output_groups=all
bazel build pkg/... --show_result=20
bazel aquery tgt
bazel build tgt --config=showpp
bazel query 'deps(tgt)'
bazel cquery 'src:Hello' --output starlark --starlark:expr='providers(target)'

etc.

Tools

@obazl//inspect

Third-party tools

CC libs

Linux

MacOS

Flags: pass with -ccopts, with or without -verbose.

 -Wa,<args> Pass the comma separated arguments in args to the assembler.
 -Xassembler <arg>        Pass arg to the assembler.


 -Wl,<args>        Pass the comma separated arguments in args to the linker.
 -Xlinker <arg>        Pass arg to the linker.

 -Wp,<args>        Pass the comma separated arguments in args to the preprocessor.
 -Xpreprocessor <arg>        Pass arg to the preprocessor.

 -Xanalyzer <arg>        Pass arg to the static analyzer.

cc verbosity: -v. This is for the cc driver, not the tools (compiler, linker, etc.)

Linker verbosity (man ld):

  • -t Logs each file (object, archive, or dylib) the linker loads. Useful for debugging problems with search paths where the wrong library is loaded.

  • -why_load Log why each object file in a static library is loaded. That is, what symbol was needed. Also called -whyload for compatibility.

  • -why_live symbol_name Logs a chain of references to symbol_name. Only applicable with -dead_strip . It can help debug why something that you think should be dead strip removed is not removed. See -exported_symbols_list for syntax and use of wildcards.

  • -print_statistics Logs information about the amount of memory and time the linker used.

  • -order_file_statistics Logs information about the processing of a -order_file.

  • -map map_file_path Writes a map file to the specified path which details all symbols and their addresses in the output image.

link version mismatch

E.g.

.../libzstd.a[23](zstdmt_compress.o)) was built for newer 'macOS' version (14.5) than being linked (14.0)

Fix: set -mmacosx-version-min