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authorAlexey Brodkin <Alexey.Brodkin@synopsys.com>2015-07-14 12:05:20 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2015-07-15 11:57:28 -0300
commit3c71ba3f80bbd476bbfb2a008da9b676031cbd32 (patch)
tree62ee9c21670b825e50b7c8e6d92f0b2948977ec2 /tools
parenta7fde09a78a8ae40b81cfb5096c3cefef6c078c9 (diff)
downloadlwn-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>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/Makefile.perf19
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