Messages in this thread Patch in this message | | | Date | Mon, 6 Feb 2017 10:38:59 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH 3/4] tools lib feature: Do not redefine compiler configuration |
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Em Wed, Feb 01, 2017 at 10:38:03PM -0800, David Carrillo-Cisneros escreveu: > Feature detection redefines CC, CCX and PKG_CONFIG, making the > output of feature detection inconsistent with the actual features > available during compilation when the above variables are used. > > Fix it by using conditional assignment.
This one is tricky, the real meaning of that line got lost somewhere, its original intent, in commit 8b6eb56a9570 ("tools/perf/build: Add 'autodep' functionality, generate feature test dependencies automatically") was to just add that "-MD" to whatever definition CC had, be it the default one or a value set by the user in the make command line.
At some point someone added that CROSS_COMPILE there, which it should have gotten from the default CC definition
It was here: a8a5cd8b472c ("perf: tools: Fix cross building")
perf: tools: Fix cross building
Currently the feature-checks Makefile does not inherit $(CC), and calls cc rather than $(CROSS_COMPILE)gcc. Thus the feature checks invoke the native toolchain rather than the cross toolchain, and can identify features as available when they are not. This can break the build
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Mark, do you recall why can't we make tools/perf/Makefile.perf pass the definitions of CC, AR and PKG_CONFIG to tools/perf/config/Makefile (now tools/build/feature/Makefile) so that the original intent (adding -MD to whatever was in CC) can be kept?
Jiri?
- Arnaldo > Signed-off-by: David Carrillo-Cisneros <davidcc@google.com> > --- > tools/build/feature/Makefile | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile > index 3dd2c600d250..d39e76f3a063 100644 > --- a/tools/build/feature/Makefile > +++ b/tools/build/feature/Makefile > @@ -52,9 +52,9 @@ FILES= \ > > FILES := $(addprefix $(OUTPUT),$(FILES)) > > -CC := $(CROSS_COMPILE)gcc -MD > -CXX := $(CROSS_COMPILE)g++ -MD > -PKG_CONFIG := $(CROSS_COMPILE)pkg-config > +CC ?= $(CROSS_COMPILE)gcc -MD > +CXX ?= $(CROSS_COMPILE)g++ -MD > +PKG_CONFIG ?= $(CROSS_COMPILE)pkg-config > LLVM_CONFIG ?= llvm-config > > all: $(FILES) > -- > 2.11.0.483.g087da7b7c-goog
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