[test-suite] / [LNT] debugging the handling of -maltivec in SingleSource/UnitTests/Vector/Altivec/Makefile

[Will Schmidt]

Hi all, 
 I've been poking at the clang buildbots for powerpc64, specifically
trying to work out why the -maltivec flag does not get passed to the
compile steps in the Makefile within the LNT build environment.
Specifically this line:
  $(LCC) $(CPPFLAGS) $(CFLAGS) $(OPTFLAGS) $(TARGET_FLAGS) -c $< -o $@
in
 SingleSource/Makefile.singlesrc 

Per some debug, it appears that the setting of TARGET_FLAGS in 
SingleSource/UnitTests/Vector/Altivec/Makefile does *not* stick. i.e.
the Makefile currently contains: 

	FP_TOLERANCE := 0.002
	TARGET_FLAGS += -maltivec
	LCCFLAGS += -maltivec

and added debug to Makefile like so: 
+	CFLAGS += -maltivec
+	$(warning "TARGET_FLAGS is ${TARGET_FLAGS}")
+	$(warning "LCCFLAGS is ${LCCFLAGS}")
+	$(warning "FP_TOLERANCE is ${FP_TOLERANCE}")
+	$(warning "CFLAGS is ${CFLAGS}")

and to Makefile.singlesrc like so:
+	$(warning TARGET_FLAGS=${TARGET_FLAGS} LCCFLAGS=${LCCFLAGS} LDFLAGS=${LDFLAGS} CFLAGS=${CFLAGS} ) \


provides output like so:
	Makefile:16: "TARGET_FLAGS is "
	Makefile:17: "LCCFLAGS is -maltivec"
	Makefile:18: "FP_TOLERANCE is 0.002"
	Makefile:19: "CFLAGS is -maltivec"
and:
	../../../../SingleSource/Makefile.singlesrc:59: TARGET_FLAGS= LCCFLAGS=-maltivec LDFLAGS= CFLAGS=-maltivec

So TARGET_FLAGS is blank, and the intended value does not get to the
build rule.   LCCFLAGS does contain the flag, but is not actually used
as part of the build rule.

I do see what looks like special handling of TARGET_FLAGS in
lnt/tests/nt.py.  A few additional experiments in adding TARGET_FLAG and
TARGET_FLAGS2 variables confirms that TARGET_FLAGS is indeed specially
handled by the lnt.py code.  I don't fully grok the reasoning or intent
behind that behavior, but suspect it's not working quite as intended.

So two quick options are 
 - add "CFLAGS += -maltivec" line to S/U/V/A/Makefile
or
 - add $(LCCFLAGS) to the rules in SingleSource/Makefile.singlesrc .

Thoughts? 

Thanks, 
-Will




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