RIOT/dist/tools/fixdep

Rationale

• Kconfig with the --sync-deps flag creates a directory tree in the $(BINDIR) folder
• This directory tree contains dummy header files for each Kconfig configuration symbol
• fixdep is a tool from the linux kernel [1] to rewrite dependency files (*.d) to include the corresponding dummy header files
• This way, make is able to draw correct dependencies between compilation units and configuration symbols
• => --sync-deps and fixdep enable incremental compilations, i.e., only those compilation units are rebuilt, which are affected by configuration changes.

[1] 83bdc7275e/scripts/basic/fixdep.c

Changes to the original script

The patch file fixdep_riot.patch contains a few necessary changes and enhancements to fixdep.c in order to make the generated *.d dependency files compatible with our build system.

• The input parameters of fixdep are changed to:

  ./fixdep <dependency_file> <target> <sync_deps_dir>
  

• The hardcoded include/config folder location in fixdep.c is changed to be configurable (passed from the command line)
• Our Kconfig integration does not use the _MODULE suffix for configurations. This is reflected in the parsing functionality of fixdep.c