Difference between revisions of "Build Environment Effort/Gbuild Bootstrapping"

Revision as of 13:35, 13 January 2011

How gbuild starts up from a makefile

When gbuild is started with a "make" command the initial makefile in the module or repository root will:

• check if there is an basic environment set
• set the variable GBUILDDIR to the directory where the gbuild system is found
• include gbuild.mk from that directory (see details below)
• include/read:
  • all the declarations of targets relative to the current directory (module makefile)
  • all the declarations of targets in all repos
• build all target needed for the goal

What gbuild.mk does when it is included in the makefile

• It sets a few global variables: SHELL, true, false, NEWLINE, WHITESPACE, COMMA
• It includes $(GBUILDDIR)/Output.mk for the output helper functions (announce, error ...)
• It includes $(GBUILDDIR)/BuildDirs.mk to setup the variables WORKDIR, OUTDIR, REPODIR
• It set up some global variables: gb_PRODUCT, gb_DEBUGLEVEL, gb_ENABLE_PCH, gb_FULLDEPS
• It includes $(GBUILDDIR)/Helper.mk for the global registries and misc. helper functions
• It includes $(GBUILDDIR)/TargetLocations.mk for the functions that return the filesystem paths for targets
• It sets up the global registries
• It reads all the Repository.mk files in the repository root (from gb_REPOS). This:
  • sets up the name for the repository (for example: SRCDIR)
  • sets up the group a library or executable belongs to
• It then reads the platform specific part from $(GBUILDDIR)/platform. This:
  • sets up the layer a library/executable belongs to by the group of the library
  • sets up the filename of the libraries and executables by the group of the library (on windows, this is the lib-file)
  • sets up the dll filename of the library (windows only)
  • sets up the rpaths for the layers (solaris and linux only - and macosx in its own special way)
• It then reads the RepositoryFixes.mk files in the repository root (from gb_REPOS). This is to keep compatibility with some unwarranted creativity in naming libraries. For example the default filenames created for the platform can be overwritten here.
• It then collects all the libraries that are known from the registries. Linking is only allowed against known libraries.
• It then sets up the global defines for C/C++ compilation
• It then reads $(GBUILDDIR)/Deliver.mk for the copy to OUTDIR commands and the collecting of filenames for the deliver.log
• It then reads all the specific classes with the build rules for the targets: ComponentTarget, AllLangResTarget, LinkTarget, ....
• It then reads any file ending with .mk in $(GBUILDDIR)/extensions