From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rasmus Villemoes Date: Fri, 28 Feb 2020 08:42:21 +0000 Subject: [PATCH] common/board_f.c: use #ifdefs a little more consistently In-Reply-To: References: <20200227081825.11039-1-rasmus.villemoes@prevas.dk> Message-ID: <76d3bc74-0406-cd11-8793-b2192ffdb7ee@prevas.dk> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 28/02/2020 00.40, Simon Glass wrote: > Hi Rasmus, > > On Thu, 27 Feb 2020 at 00:18, Rasmus Villemoes > wrote: >> >> Some init functions, e.g. print_resetinfo(), are conditionally defined >> depending on some config options, and are correspondingly >> conditionally included in the init_sequence_f[] array. >> >> Others are unconditionally defined and included in init_sequence_f[], >> but have their entire body, sans a mandatory "return 0", conditionally >> compiled. >> >> For the simple cases, switch to the former model, making it a bit more >> consistent. This also makes the U-Boot image very slightly smaller and >> avoids a few useless calls to no-op functions during board_init_f. > > Can you check if it definitely does change the size? It does, I did build to see how much. On ppc, it's 8 bytes per no-op function (one "put 0 in r3", one blr instruction), plus 4 bytes for the array entry, plus 4 bytes for a .fixup entry - in my case ending up with 7*16=112, because all but the #ifndef CONFIG_OF_EMBED applied. The reason I ask > is that it inlines those function calls in the normal case, at least > from my inspection. The compiler can't inline and thus eliminate these as they are not called directly, but their addresses are used to populate the init_sequence_f[] array and called through that. > Using if() is preferable to #if if there is no cost. Completely agree, and I also prefer to have the linker eliminate unused functions rather than cluttering the C code with #ifdefs. But that can't be used in this case. Anyway, this wasn't primarily to save 112 bytes or whatnot from the U-Boot image, just to use one style a little more consistently. Rasmus