Trace: • how

The How

  • no depencencies other than the c++-20 compiler
  • the REG macro - automatic int a = registerFunction() wrapper.
  • std::filesystem for reading timestamps
  • execv, posix_spawn and friends for executing the compiler, linker and other tools
  • std::async for parallel compilation
  • std::thread::hardware_concurrency() for automatic -jn deduction
  • gcc -MMD for dependency tracking
  • configure target
    • cross-compilation and tool-chain control
  • trixy self-re-invoke (after re-compilation) when configuration files change.
    • tree of self-dependency weirdness:
      • main()
2    if configure arg call configure(args), exit
4    if reconfigure arg call reconfigure(args), exit
1,3  other rebuildCheck
1    build dirty project sources...

configure(args)
  collect (relevant) env vars in map: A
	collect (relevant) cli args in map: B
  call generateCache(A, B)
  then call rebuildCheck to force rebuild and then exit

reconfigure(args)
  read A and B from (current) config cache and call generateCache(A, B) to
	 generate a new one
  then call rebuildCheck to rebuild and then exit

rebuildCheck()
  check if rebuild is needed (if any ctor.cc files or configuration.cc changed):
	  rebuild
		if !"only configuration.cc changed" re-run, with "reconfigure" argument

generateCache(A, B)
  resolv tool-chain (compiler, linker, etc) and store in map: C
  run through externals and resolv them, store results in map: D
	generate config cache .cc file with A, B, C and D
Scenarios:

1. No ctor deps changed (normal run)
   rebuild dirty project sources.
 OK

2. a new configuration.cc has been generated (user called configure)
   regenerate cache
 * rebuild
 OK

3. one or more ctor.cc files changed (run with args)
 * rebuild
   relaunch with 'reconfigure' with args (goto 4)
 OK

4. run with reconfigure (with other args)
   "ignore" args but keep them for later
   regenerate cache
 * rebuild
   relauch with "other args" (goto 1)
 OK
  • independent target compilation (with dependency deduction)
  • clean target
  • bootstrapping (yes - libctor compiles itself)
  • check target, for unit test compilation and execution
  • compilation-database (json) for c-lion and others
  • currently working on:
    • external dependency flags with std::variant
      • manual dependency
      • automatic dependency deduction through searches
  • future work:
    • more external dependency variants:
      • pkg-config
      • conan
    • pre-/postbuild actions with conditions
    • globbing
    • custom target generation through external application (generators)
    • lambda functions as generators
    • custom compilation configuration control through configure target (like –with-X/–enable-Y in autotools)
    • install target with PREFIX and DESTDIR support
    • documentation :-)