Messages in this thread Patch in this message | | | From | Alexey Brodkin <> | Subject | [PATCH] perf tools: Really allow to specify custom CC, AR or LD | Date | Tue, 14 Jul 2015 12:05:20 +0300 |
| |
Commit 5ef7bbb09f7b ("perf tools: Allow to specify custom linker command") was meant to enable usage non $(CROSS_COMPILE)ld linker during perf building. But implementation didn't take in account fact that LD is a pre-defined variable in GNU Make. I.e. it is always defined. Which means there's no point to check "LD ?= ..." because it will never succeed. And so LD will be either that explicitly passed to make like this: ------->8------- make LD=path_to_my_ld ... ------->8------- or default value, which is host's "ld".
Latter leads to failure of cross-linkage because instead of cross linker "$(CROSS_COMPILE)ld" host's "ld" is used.
Fortunately there's a way to do correct substitution of $(CROSS_COMPILE)ld with user defined LD on command-line.
As a reference was used implementation in "tools/lib/traceevent/Makefile".
Build tested for x86_64 and ARC.
Thanks Jiri for this hint.
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Aaro Koskinen <aaro.koskinen@nokia.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: linux-kernel@vger.kernel.org --- tools/perf/Makefile.perf | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-)
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf index 7a4b549..bba3463 100644 --- a/tools/perf/Makefile.perf +++ b/tools/perf/Makefile.perf @@ -109,9 +109,22 @@ $(OUTPUT)PERF-VERSION-FILE: ../../.git/HEAD $(Q)$(SHELL_PATH) util/PERF-VERSION-GEN $(OUTPUT) $(Q)touch $(OUTPUT)PERF-VERSION-FILE -CC = $(CROSS_COMPILE)gcc -LD ?= $(CROSS_COMPILE)ld -AR = $(CROSS_COMPILE)ar +# Makefiles suck: This macro sets a default value of $(2) for the +# variable named by $(1), unless the variable has been set by +# environment or command line. This is necessary for CC and AR +# because make sets default values, so the simpler ?= approach +# won't work as expected. +define allow-override + $(if $(or $(findstring environment,$(origin $(1))),\ + $(findstring command line,$(origin $(1)))),,\ + $(eval $(1) = $(2))) +endef + +# Allow setting CC and AR and LD, or setting CROSS_COMPILE as a prefix. +$(call allow-override,CC,$(CROSS_COMPILE)gcc) +$(call allow-override,AR,$(CROSS_COMPILE)ar) +$(call allow-override,LD,$(CROSS_COMPILE)ld) + PKG_CONFIG = $(CROSS_COMPILE)pkg-config RM = rm -f -- 2.4.3
| |