Messages in this thread | | | From | Alexey Brodkin <> | Subject | Re: [PATCH] Revert "perf tools: Allow to specify custom linker command" | Date | Tue, 14 Jul 2015 14:00:05 +0000 |
| |
Hi Arnaldo,
On Tue, 2015-07-14 at 10:46 -0300, Arnaldo Carvalho de Melo wrote: > Em Mon, Jul 13, 2015 at 11:24:06PM +0300, Aaro Koskinen escreveu: > > Hi, > > > > On Mon, Jul 13, 2015 at 02:10:53PM +0300, Alexey Brodkin wrote: > > > This reverts commit 5ef7bbb09f7b > > > ("perf tools: Allow to specify custom linker command"). > > > > > > LD is a pre-defined variable in GNU Make. I.e. it is always defined. > > > Which means there's no point to check "LD ?= ..." because it will never > > > succeed. And so LD will be either that explicitly passed to make like > > > this: > > > ------->8------- > > > make LD=path_to_my_ld ... > > > ------->8------- > > > or default value, which is host's "ld". > > > > > > Latter leads to failure of cross-linkage because instead of cross linker > > > "$(CROSS_COMPILE)ld" host's "ld" is used. > > > > > > As for commit which is reverted here: > > > [1] Usually for selection of non-default flavour of CPU core/options > > > linker flags are used like "-mtune=xxx" or "-mMyCPUType" etc. > > > > > > [2] Still to implement ability to use "ld" that differs from > > > "$(CROSS_COMPILE)ld" one will need to add new makefile variable like > > > TARGET_LD and then check if $(TARGET_LD) is not specified on make > > > invocation then use "$(CROSS_COMPILE)ld". > > > > > > But for now to fix cross-building of perf this revert is enough. > > > > Hmm. You are probably right, my build system always exports LD with > > correct linker for cross builds so perhaps that's why I this "worked" > > for me when testing. Sorry. > > So, I think this is an "Acked-by: Aaro Koskinen <aaro.koskinen@iki.fi>" > for the revert, right? > > > I guess the correct fix would be [1], i.e. there should be some new > > variable to pass flags to ld command. > > > > Or maybe [2], could we use make "origin" function? If LD is "default", > > then use "$(CROSS_COMPILE)ld", otherwise use what the user passed? > > When you guys get to some conclusion, please submit a new patch, for now > I am taking the revert with the (implied) Acked-by Aaro, ok?
Please find my patch that both reverts initial Aaro's patch and implements proper handling of CC, AR and LD substitution here - https://lkml.org/lkml/2015/7/14/149
-Alexey
| |