> This has a long and complicated history. I tried to explain some of that here: > > http://gcc.gnu.org/ml/gcc-bugs/2010-12/msg01493.html > > I wasn't part of the GCC community at the time, but I think that > .ctors was originally used instead of .init or .init_array precisely > because the order of execution of .init/.init_array was backwards from > the desired order of execution for constructors (leaving aside the > fact that it was backwards from the desired order of execution for > *any* kind of initializer). Now that GCC has finally moved from .init > to .init_array, they're simply trying to consolidate on the One True > Initializer Mechanism. In doing so, it would be desirable to correct > that mistake we made so long ago in the gABI, but that's where we ran > up against the concerns of the Chrome and Firefox developers who care > more about startup performance than about constructor ordering (but, > apparently, not enough to use linker options to reorder the code in > order to get both good performance *and* proper execution order).
Just a bit of context: I tried to build chrome in order to test a completely unrelated change (it is an awesome compiler test case) and got a protocol compiler crash, which is where all this started. I don't work with chrome or know why they are using gold 2.21. I do work on firefox and we are using centos 5's linker and gcc 4.5 :-( But I am still missing something, why is the performance so different? Code layout putting the constructors' body in the reverse order they are called? > -cary Cheers, Rafael
