diff mbox

[v2,1/2] trace: fix make foo-timestamp rules

Message ID 1446198795-6081-2-git-send-email-stefanha@redhat.com
State New
Headers show

Commit Message

Stefan Hajnoczi Oct. 30, 2015, 9:53 a.m. UTC 
The Makefile uses intermediate timestamp files to avoid rebuilding if
tracetool output is unchanged.

Timestamps are implemented incorrectly.  This was fixed for rules.mak in
commit 4b25966ab976f3a7fd9008193b2defcc82f8f04d ("rules.mak: cleanup
config generation rules") but never fixed in trace/Makefile.objs.

The problem with the old timestamp implementation was that make doesn't
notice the updated file modification time until the next time it is run.
It was necessary to run make twice in a row to achieve a full rebuild.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 trace/Makefile.objs | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)
diff mbox

Patch

diff --git a/trace/Makefile.objs b/trace/Makefile.objs
index 32f7a32..73bec38 100644
--- a/trace/Makefile.objs
+++ b/trace/Makefile.objs
@@ -5,20 +5,20 @@ 
 
 ifeq ($(findstring ust,$(TRACE_BACKENDS)),ust)
 $(obj)/generated-ust-provider.h: $(obj)/generated-ust-provider.h-timestamp
+	@cmp $< $@ >/dev/null 2>&1 || cp $< $@
 $(obj)/generated-ust-provider.h-timestamp: $(SRC_PATH)/trace-events
 	$(call quiet-command,$(TRACETOOL) \
 		--format=ust-events-h \
 		--backends=$(TRACE_BACKENDS) \
 		< $< > $@,"  GEN   $(patsubst %-timestamp,%,$@)")
-	@cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst %-timestamp,%,$@)
 
 $(obj)/generated-ust.c: $(obj)/generated-ust.c-timestamp $(BUILD_DIR)/config-host.mak
+	@cmp $< $@ >/dev/null 2>&1 || cp $< $@
 $(obj)/generated-ust.c-timestamp: $(SRC_PATH)/trace-events
 	$(call quiet-command,$(TRACETOOL) \
 		--format=ust-events-c \
 		--backends=$(TRACE_BACKENDS) \
 		< $< > $@,"  GEN   $(patsubst %-timestamp,%,$@)")
-	@cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst %-timestamp,%,$@)
 
 $(obj)/generated-events.h: $(obj)/generated-ust-provider.h
 $(obj)/generated-events.c: $(obj)/generated-ust.c
@@ -28,20 +28,20 @@  endif
 # Auto-generated event descriptions
 
 $(obj)/generated-events.h: $(obj)/generated-events.h-timestamp
+	@cmp $< $@ >/dev/null 2>&1 || cp $< $@
 $(obj)/generated-events.h-timestamp: $(SRC_PATH)/trace-events
 	$(call quiet-command,$(TRACETOOL) \
 		--format=events-h \
 		--backends=$(TRACE_BACKENDS) \
 		< $< > $@,"  GEN   $(patsubst %-timestamp,%,$@)")
-	@cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst %-timestamp,%,$@)
 
 $(obj)/generated-events.c: $(obj)/generated-events.c-timestamp $(BUILD_DIR)/config-host.mak
+	@cmp $< $@ >/dev/null 2>&1 || cp $< $@
 $(obj)/generated-events.c-timestamp: $(SRC_PATH)/trace-events
 	$(call quiet-command,$(TRACETOOL) \
 		--format=events-c \
 		--backends=$(TRACE_BACKENDS) \
 		< $< > $@,"  GEN   $(patsubst %-timestamp,%,$@)")
-	@cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst %-timestamp,%,$@)
 
 util-obj-y += generated-events.o
 
@@ -81,12 +81,12 @@  $(obj)/generated-tracers.o: $(obj)/generated-tracers.c $(obj)/generated-tracers.
 # rule file. So we use '.dtrace' instead
 ifeq ($(findstring dtrace,$(TRACE_BACKENDS)),dtrace)
 $(obj)/generated-tracers-dtrace.dtrace: $(obj)/generated-tracers-dtrace.dtrace-timestamp
+	@cmp $< $@ >/dev/null 2>&1 || cp $< $@
 $(obj)/generated-tracers-dtrace.dtrace-timestamp: $(SRC_PATH)/trace-events $(BUILD_DIR)/config-host.mak
 	$(call quiet-command,$(TRACETOOL) \
 		--format=d \
 		--backends=$(TRACE_BACKENDS) \
 		< $< > $@,"  GEN   $(patsubst %-timestamp,%,$@)")
-	@cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst %-timestamp,%,$@)
 
 $(obj)/generated-tracers-dtrace.h: $(obj)/generated-tracers-dtrace.dtrace
 	$(call quiet-command,dtrace -o $@ -h -s $<, "  GEN   $@")
@@ -100,28 +100,28 @@  endif
 # Translation level
 
 $(obj)/generated-helpers-wrappers.h: $(obj)/generated-helpers-wrappers.h-timestamp
+	@cmp $< $@ >/dev/null 2>&1 || cp $< $@
 $(obj)/generated-helpers-wrappers.h-timestamp: $(SRC_PATH)/trace-events $(BUILD_DIR)/config-host.mak
 	$(call quiet-command,$(TRACETOOL) \
 		--format=tcg-helper-wrapper-h \
 		--backend=$(TRACE_BACKENDS) \
 		< $< > $@,"  GEN   $(patsubst %-timestamp,%,$@)")
-	@cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst %-timestamp,%,$@)
 
 $(obj)/generated-helpers.h: $(obj)/generated-helpers.h-timestamp
+	@cmp $< $@ >/dev/null 2>&1 || cp $< $@
 $(obj)/generated-helpers.h-timestamp: $(SRC_PATH)/trace-events $(BUILD_DIR)/config-host.mak
 	$(call quiet-command,$(TRACETOOL) \
 		--format=tcg-helper-h \
 		--backend=$(TRACE_BACKENDS) \
 		< $< > $@,"  GEN   $(patsubst %-timestamp,%,$@)")
-	@cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst %-timestamp,%,$@)
 
 $(obj)/generated-helpers.c: $(obj)/generated-helpers.c-timestamp
+	@cmp $< $@ >/dev/null 2>&1 || cp $< $@
 $(obj)/generated-helpers.c-timestamp: $(SRC_PATH)/trace-events $(BUILD_DIR)/config-host.mak
 	$(call quiet-command,$(TRACETOOL) \
 		--format=tcg-helper-c \
 		--backend=$(TRACE_BACKENDS) \
 		< $< > $@,"  GEN   $(patsubst %-timestamp,%,$@)")
-	@cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst %-timestamp,%,$@)
 
 $(obj)/generated-helpers.o: $(obj)/generated-helpers.c
 
@@ -129,12 +129,12 @@  target-obj-y += generated-helpers.o
 
 
 $(obj)/generated-tcg-tracers.h: $(obj)/generated-tcg-tracers.h-timestamp
+	@cmp $< $@ >/dev/null 2>&1 || cp $< $@
 $(obj)/generated-tcg-tracers.h-timestamp: $(SRC_PATH)/trace-events $(BUILD_DIR)/config-host.mak
 	$(call quiet-command,$(TRACETOOL) \
 		--format=tcg-h \
 		--backend=$(TRACE_BACKENDS) \
 		< $< > $@,"  GEN   $(patsubst %-timestamp,%,$@)")
-	@cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst %-timestamp,%,$@)
 
 
 ######################################################################