Fix PR1040:

Don't rebuild llvm-config if none of the library dependencies changed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32455 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/tools/llvm-config/Makefile b/tools/llvm-config/Makefile
index 354723ab2bbc72af50da10a887b3ccc77b16c118..410808b1f269ed3ed99e94fc977ec2551b21b130 100644 (file)
--- a/tools/llvm-config/Makefile
+++ b/tools/llvm-config/Makefile
@@ -29,11 +29,16 @@ SUB_LDFLAGS =
 
 FinalLibDeps = $(PROJ_OBJ_DIR)/FinalLibDeps.txt
 LibDeps      = $(PROJ_OBJ_DIR)/LibDeps.txt
+LibDepsTemp  = $(PROJ_OBJ_DIR)/LibDeps.txt.tmp
 GenLibDeps   = $(PROJ_SRC_ROOT)/utils/GenLibDeps.pl
 
-$(LibDeps): $(GenLibDeps) $(LibDir) $(wildcard $(LibDir)/*.a $(LibDir)/*.o)
-       $(Echo) "Regenerating LibDeps.txt"
-       $(Verb) $(GenLibDeps) -flat $(LibDir) $(NM_PATH) > $(LibDeps)
+$(LibDepsTemp): $(GenLibDeps) $(LibDir) $(wildcard $(LibDir)/*.a $(LibDir)/*.o)
+       $(Echo) "Regenerating LibDeps.txt.tmp"
+       $(Verb) $(GenLibDeps) -flat $(LibDir) $(NM_PATH) > $(LibDepsTemp)
+
+$(LibDeps): $(LibDepsTemp)
+       $(Verb) $(CMP) -s $@ $< || ( $(CP) $< $@ && \
+         $(EchoCmd) Updated LibDeps.txt because dependencies changes )
 
 # Find all the cyclic dependencies between various LLVM libraries, so we
 # don't have to process them at runtime.