I was looking on the kernel-janitors site at the To Do list and found this task below, which I decided to try my hand at. (http://www.kerneljanitors.org/TODO)
> 1) The string form > > [const] char *foo = "blah"; > > creates two variables in the final assembly output, a static string, and > a char pointer to the static string. The alternate string form > > [const] char foo[] = "blah"; > > is better because it declares a single variable. > > For variables marked __initdata, the "*foo" form causes only the > pointer, not the string itself, to be dropped from the kernel image, > which is a bug. Using the "foo[]" form with regular 'ole local > variables also makes the assembly shorter. > However, I was advised by a list member that this work was of uncertain benefit: > Ricardo Nabinger Sanchez wrote: > > By May, 2005, I was working on this. Alexey told me that besides what gcc > should do, I had to confirm that the change made was actually better. > > In some cases, it was not. I've made a testcase, and the results were > pretty odd (I was expecting something else): > > http://lists.osdl.org/pipermail/kernel-janitors/2005-May/004146.html > > Different versions of gcc and cross-compilers should produce different > results. I really don't know yet what is the best case (ie, which is good > for (almost) all architectures/compilers). > > Anyone? Is anybody able to give me an authoritative answer about which for should be used? The second part of the task was descibed thus: > 2) "unsigned int" is preferred to "int", it generates better asm code on > all platforms except sh5. This replacement needs to be done manually, > because often 'int' is required due to negative values -Exxx commonly > passed as error values. Can anyone comment on the accuracy of this? Many thanks, Felix Oxley
