With GNU make 4.4, the number of execution of the command present in
these $(shell ) increased greatly. This is probably because as of make
4.4, exported variable are also added to the environment of $(shell )
construct.
Also, `make -d` shows a lot of these:
Makefile:15: not recursively expanding XEN_BUILD_DATE to export to shell
function
Makefile:16: not recursively expanding XEN_BUILD_TIME to export to shell
function
Makefile:17: not recursively expanding XEN_BUILD_HOST to export to shell
function
Makefile:14: not recursively expanding XEN_DOMAIN to export to shell
function
So to avoid having these command been run more than necessary, we
will replace ?= by an equivalent but with immediate expansion.
Reported-by: Jason Andryuk <jandr...@gmail.com>
Signed-off-by: Anthony PERARD <anthony.per...@citrix.com>
---
Notes:
v3:
- replace evaluation on first use construct by immediate expansion which
isn't likely to break and is clearer.
xen/Makefile | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/xen/Makefile b/xen/Makefile
index e8aa663781..c1738dbbde 100644
--- a/xen/Makefile
+++ b/xen/Makefile
@@ -11,10 +11,18 @@ export XEN_FULLVERSION =
$(XEN_VERSION).$(XEN_SUBVERSION)$(XEN_EXTRAVERSION)
-include xen-version
export XEN_WHOAMI ?= $(USER)
-export XEN_DOMAIN ?= $(shell ([ -x /bin/dnsdomainname ] &&
/bin/dnsdomainname) || ([ -x /bin/domainname ] && /bin/domainname || echo
[unknown]))
-export XEN_BUILD_DATE ?= $(shell LC_ALL=C date)
-export XEN_BUILD_TIME ?= $(shell LC_ALL=C date +%T)
-export XEN_BUILD_HOST ?= $(shell hostname)
+ifeq ($(origin XEN_DOMAIN), undefined)
+export XEN_DOMAIN := $(shell ([ -x /bin/dnsdomainname ] &&
/bin/dnsdomainname) || ([ -x /bin/domainname ] && /bin/domainname || echo
[unknown]))
+endif
+ifeq ($(origin XEN_BUILD_DATE), undefined)
+export XEN_BUILD_DATE := $(shell LC_ALL=C date)
+endif
+ifeq ($(origin XEN_BUILD_TIME), undefined)
+export XEN_BUILD_TIME := $(shell LC_ALL=C date +%T)
+endif
+ifeq ($(origin XEN_BUILD_HOST), undefined)
+export XEN_BUILD_HOST := $(shell hostname)
+endif
# Best effort attempt to find a python interpreter, defaulting to Python 3 if
# available. Fall back to just `python` if `which` is nowhere to be found.
--
Anthony PERARD
