Prevent absolute paths being embedded in binaries

[ptheywood]

Debug info and the use of __FILE__ embed absolute paths into binary files, which is probably bad if we end up distributing any pre-compiled files.

GCC/clang support -fdebug-prefix-map=OLD=NEW as a way of changing paths in debug info.

More recent GCC / Clang also support modifying the behaviour of __FILE__ via -fmacro-prefix-map=OLD=NEW. -ffile-prefix-map=OLD=NEW can be used to set both these options.

source

I am unsure if NVCC / MSVC will have comparible options (I've not yet looked). This might include use of -lineinfo/-G in NVCC.
Worth checking to see if Cmake has a feature for these.

Cmake may also need some changins making, as it embeds some paths into the binary by default.

• Some comments on the nvidia developer forums suggest NVCC does not support this (or atleast didn't?)
• MSVC doesn't appear to support a similar option (source)
  • Although there is an undocumented experimental flag which might be relevant (in the future?) experimental:deterministic

For GCC Clang versions which support it, rough cmake would be:

target_compile_options(target PUBLIC "-ffile-prefix-map=${CMAKE_SOURCE_DIR}=.")

[ptheywood]

This is probably relevant prior to any binary releases? #514

[ptheywood]

Rob suggested that we could just prune the __FILE__ value from the exception printing so that it starts with include/flamepgu?, Not as nice as preventing the strings from being embedded, but should work on compilers which do not support the use of __FILE__ and relative paths.

Will also need to consider exceptions trhwon from src/flamegpu too

[ptheywood]

Using -ffile-prefix-map where appropriate on gcc /clang does appear to work, and works for hots compilation of NVCC (but probably not for device code?)

# in game of life main.cu::main()
printf("FILE LINE %s:%d\n", __FILE__, __LINE__);
# before 
FILE LINE /home/ptheywood/code/flamegpu/FLAMEGPU2/examples/game_of_life/src/main.cu:35
# after 
FILE LINE ./examples/game_of_life/src/main.cu:35

Although i'm not super keen on it starting with the . but I'm not sure what the alt would be.