On 08/09/2015 20:35, Markus Armbruster wrote: >> > Having not used Coccinelle yet, what happens if any of these functions >> > become desynchronized ? > Coccinelle transforms C to C. Problem: if you parse C the normal way > (first run preprocessor, then the parser proper), you have to unparse > and unpreprocess at the end to get a useful result. Unparsing is easy, > but unpreprocessing is hard. > > Instead, Coccinelle tries to parse *unpreprocessed* C. Works most of > the time, because most uses of function-like macros can be treated as if > they were function calls, and most uses of object-like macros can be > treated as if they were values. > > When it doesn't work, Coccinelle needs to resort to magic and / or skip > over some code it can't decipher. The latter is undesirable, because if > the skipped code contains something we'd like to transform, we won't. > > Part of the magic is treating "bad" macros specially. --macro-file > helps with that part: macros defined there are "bad". Sorry, I can't > really explain it, -EMAGIC. /usr/share/coccinelle/standard.h is used by > default. > > So what happens when the this file gets out of sync? Worst case is > Coccinelle misses a pattern it could find if it was in sync. > > Provided the macro file makes sense initially, a moderately bit-rotten > version is still almost certainly better than nothing.
Great answer. I'll only add that exactly the same issue happens with the Coverity model. Paolo
