On Sun, Nov 11, 2012 at 8:26 AM, David Held <[email protected]> wrote: > While writing some unit tests for Dsymbol, I noticed that > Dsymbol::toPrettyChars() leaks almost everywhere. In the simple case where > a symbol has no parent, it just returns toChars(), which does not leak (at > least I don't think it does). However, whenever the symbol has a parent (or > many), the returned string is composed, which requires that it is allocated > dynamically (via mem.malloc()). Even though the caller owns the string, and > even though it is called dozens of times, it appears that none of the > callers are properly disposing of the result. Unfortunately, it is a bit > messy to do so, because you must free the string *only* if it has a parent, > which is a pretty bad implementation leak, IMO. Here is a place where > std::string would have worked nicely. ;) > > I suspect this has gone unnoticed because A) dmd probably has a relatively > small memory footprint to begin with or B) most invokations of > toPrettyChars() are during a call to error(), so the compiler is about to > quit anyway. What to do? Leave it alone? Try to fix it? Note that fixing > it without changing toPrettyChars() would require adding 2-3 lines of code > to almost every call. > > Dave > > > P.S. Incidentally, this bug is one that is not easily caught with > assertions (where would you place the assert that the string was freed?). > Fortunately, it is caught by unit testing; but it could also have been > caught by documenting that the caller owns the string. This is why you > really want all 3 approaches to code quality.
DMD as a whole is written for garbage collection. It just so happens that it doesn't use one at the moment, which means a lot of things will leak. Regards, Alex _______________________________________________ dmd-internals mailing list [email protected] http://lists.puremagic.com/mailman/listinfo/dmd-internals
