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[Qemu-devel] [PATCH 2/2] trace: avoid unnecessary recompilation if nothi
From: |
Blue Swirl |
Subject: |
[Qemu-devel] [PATCH 2/2] trace: avoid unnecessary recompilation if nothing changed |
Date: |
Sun, 26 Sep 2010 09:05:55 +0000 |
Add logic to detect changes in generated files. If the old
and new files are identical, don't touch the generated file.
This avoids a lot of churn since many files depend on trace.h.
Signed-off-by: Blue Swirl <address@hidden>
---
Makefile | 18 ++++++++++++++++--
1 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/Makefile b/Makefile
index ff39025..085e8ed 100644
--- a/Makefile
+++ b/Makefile
@@ -107,10 +107,24 @@ ui/vnc.o: QEMU_CFLAGS += $(VNC_TLS_CFLAGS)
bt-host.o: QEMU_CFLAGS += $(BLUEZ_CFLAGS)
trace.h: $(SRC_PATH)/trace-events config-host.mak
- $(call quiet-command,sh $(SRC_PATH)/tracetool --$(TRACE_BACKEND) -h
< $< > $@," GEN $@")
+ $(call quiet-command,sh $(SRC_PATH)/tracetool --$(TRACE_BACKEND) -h
< $< > address@hidden," GEN $@")
+ @if test -f $@; then \
+ if ! cmp -s $@ address@hidden; then \
+ mv address@hidden $@; \
+ fi; \
+ else \
+ mv address@hidden $@; \
+ fi
trace.c: $(SRC_PATH)/trace-events config-host.mak
- $(call quiet-command,sh $(SRC_PATH)/tracetool --$(TRACE_BACKEND) -c
< $< > $@," GEN $@")
+ $(call quiet-command,sh $(SRC_PATH)/tracetool --$(TRACE_BACKEND) -c
< $< > address@hidden," GEN $@")
+ @if test -f $@; then \
+ if ! cmp -s $@ address@hidden; then \
+ mv address@hidden $@; \
+ fi; \
+ else \
+ mv address@hidden $@; \
+ fi
trace.o: trace.c $(GENERATED_HEADERS)
--
1.6.2.4
- [Qemu-devel] [PATCH 2/2] trace: avoid unnecessary recompilation if nothing changed,
Blue Swirl <=