libxl, buildmakevars2file: Do not relink libxl each time

Make Config.mk's definition of buildmakevars2file and
tools/libxl/Makefile's rule for _libxl_paths.h generate their files to
temporary files and only rename them into place if the intended file
has changed.  This gets rid of unnecessarily compilation and link
steps.

Add *.tmp to .hgignore.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Keir Fraser <keir.fraser@citrix.com>

diff --git a/.hgignore b/.hgignore
index 965992d787f5943587710cae659233b0b806d695..e9c08742e7e233f93b987a77dbf121dd5beb868c 100644 (file)
--- a/.hgignore
+++ b/.hgignore
@@ -11,6 +11,7 @@
 .*\.tar\.bz2$
 .*\.tar\.gz$
 .*~$
+.*\.tmp$
 .*\.flc$
 .*\.orig$
 .*\.rej$

diff --git a/Config.mk b/Config.mk
index f80732a618102a2cb0f702db3a198de8a6579360..33a26352499120bb8749f60b1bf30cdfb68f4718 100644 (file)
--- a/Config.mk
+++ b/Config.mk
@@ -120,16 +120,17 @@ buildmakevars2file = $(eval $(call buildmakevars2file-closure,$(1)))
 define buildmakevars2file-closure
     .PHONY: genpath
     genpath:
-       rm -f $(1);                                                    \
-       echo "SBINDIR=\"$(SBINDIR)\"" >> $(1);                         \
-       echo "BINDIR=\"$(BINDIR)\"" >> $(1);                           \
-       echo "LIBEXEC=\"$(LIBEXEC)\"" >> $(1);                         \
-       echo "LIBDIR=\"$(LIBDIR)\"" >> $(1);                           \
-       echo "SHAREDIR=\"$(SHAREDIR)\"" >> $(1);                       \
-       echo "PRIVATE_BINDIR=\"$(PRIVATE_BINDIR)\"" >> $(1);           \
-       echo "XENFIRMWAREDIR=\"$(XENFIRMWAREDIR)\"" >> $(1);           \
-       echo "XEN_CONFIG_DIR=\"$(XEN_CONFIG_DIR)\"" >> $(1);           \
-       echo "XEN_SCRIPT_DIR=\"$(XEN_SCRIPT_DIR)\"" >> $(1)
+       rm -f $(1).tmp;                                                    \
+       echo "SBINDIR=\"$(SBINDIR)\"" >> $(1).tmp;                         \
+       echo "BINDIR=\"$(BINDIR)\"" >> $(1).tmp;                           \
+       echo "LIBEXEC=\"$(LIBEXEC)\"" >> $(1).tmp;                         \
+       echo "LIBDIR=\"$(LIBDIR)\"" >> $(1).tmp;                           \
+       echo "SHAREDIR=\"$(SHAREDIR)\"" >> $(1).tmp;                       \
+       echo "PRIVATE_BINDIR=\"$(PRIVATE_BINDIR)\"" >> $(1).tmp;           \
+       echo "XENFIRMWAREDIR=\"$(XENFIRMWAREDIR)\"" >> $(1).tmp;           \
+       echo "XEN_CONFIG_DIR=\"$(XEN_CONFIG_DIR)\"" >> $(1).tmp;           \
+       echo "XEN_SCRIPT_DIR=\"$(XEN_SCRIPT_DIR)\"" >> $(1).tmp;           \
+       if ! cmp $(1).tmp $(1); then mv -f $(1).tmp $(1); fi
 endef
 
 ifeq ($(debug),y)

diff --git a/tools/libxl/Makefile b/tools/libxl/Makefile
index 9f74d4b28432590aedaa8ada461f503458679982..d0be502e1d19f3e9671f395f206f54552c2b15e6 100644 (file)
--- a/tools/libxl/Makefile
+++ b/tools/libxl/Makefile
@@ -52,12 +52,12 @@ $(LIBXLU_OBJS): $(AUTOINCS)
        @rm -f $*.[ch]
        $(FLEX) --header-file=$*.h --outfile=$*.c $<
 
-genpath-target = $(call buildmakevars2file,_libxl_paths.h)
+genpath-target = $(call buildmakevars2file,_libxl_paths.h.tmp)
 $(eval $(genpath-target))
 
 _libxl_paths.h: genpath
-       sed -e "s/\([^=]*\)=\(.*\)/#define \1 \2/g" $@ >_$@
-       mv _$@ $@
+       sed -e "s/\([^=]*\)=\(.*\)/#define \1 \2/g" $@.tmp >$@.2.tmp
+       if ! cmp $@.2.tmp $@; then mv -f $@.2.tmp $@; fi
 
 libxl_paths.c: _libxl_paths.h