Hi!
When working with unit tests I frequently have the need to override a function or variable in a shared library. This works just as I want for global symbols, but if the symbol is local (declared static) I have to modify the source (remove the static using a STATIC preprocessor define) to make it work.
The setup is as follows: app/Makefile app/src.c app/checktests/Makefile app/checktests/tests.c
In the application Makefile I have a target to compile the application as a shared library. This target is invoked from the checktests Makefile and the lib is then linked with the tests. So I compile the application source under test from scratch and can control the flags. (To mess even less with the application under test I may change the setup in the future to include the application Makefile in a wrapper Makefile instead of adding a shared library target to it.)
All this makes it possible to override any global symbols in src.c by defining the symbol in the tests.c file. What I miss is the possibility to override local symbols in a similar manner, without touching the source. This problem could be fixed by adding some options to gcc to globalize symbols.
My proposal is the following new options: -fglobalize-symbol=SYMBOLNAME -fglobalize-symbols=FILENAME -fglobalize-all-symbols
The first option makes the symbol SYMBOLNAME global. The second option makes all symbols in FILENAME global. The third option makes all symbols global.
The globalization should apply to all symbols that are visible on the file scope level but not globally visible. E.g. both functions declared 'static' and variables declared 'static' (outside functions). The attribute '__attribute__ ((hidden))' may be overridden too, but for my purposes I don't have the need for this.
Waiting hopefully /HUGO.
