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| author | Alexey Brodkin <Alexey.Brodkin@synopsys.com> | 2015-07-14 12:05:20 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2015-07-15 11:57:28 -0300 |
| commit | 3c71ba3f80bbd476bbfb2a008da9b676031cbd32 (patch) | |
| tree | 62ee9c21670b825e50b7c8e6d92f0b2948977ec2 | |
| parent | a7fde09a78a8ae40b81cfb5096c3cefef6c078c9 (diff) | |
| download | lwn-3c71ba3f80bbd476bbfb2a008da9b676031cbd32.tar.gz lwn-3c71ba3f80bbd476bbfb2a008da9b676031cbd32.zip | |
perf tools: Really allow to specify custom CC, AR or LD
Commit 5ef7bbb09f7b ("perf tools: Allow to specify custom linker
command") was meant to enable usage non $(CROSS_COMPILE)ld linker during
perf building.
But implementation didn't take into account the fact that LD is a
pre-defined variable in GNU Make. I.e. it is always defined.
Which means there's no point to check "LD ?= ..." because it will never
succeed.
And so LD will be either that explicitly passed to make like this:
------->8-------
make LD=path_to_my_ld ...
------->8-------
or default value, which is host's "ld".
Latter leads to failure of cross-linkage because instead of cross linker
"$(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>
Fixes: 5ef7bbb09f7b ("perf tools: Allow to specify custom linker command")
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: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: linux-arch@vger.kernel.org
Link: http://lkml.kernel.org/r/1436864720-26316-1-git-send-email-abrodkin@synopsys.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
| -rw-r--r-- | tools/perf/Makefile.perf | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf index 7a4b549214e3..bba34636b733 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 |