diff mbox series

[XEN,v2,5/5] Config.mk: evaluate XEN_COMPILE_ARCH and XEN_OS on first use

Message ID 20230622153005.31604-6-anthony.perard@citrix.com (mailing list archive)
State Superseded
Headers show
Series build: reduce number of $(shell) execution on make 4.4 | expand

Commit Message

Anthony PERARD June 22, 2023, 3:30 p.m. UTC 
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.

So, to avoid having these command been run more than necessery, we
will use a construct to evaluate on first use.

Reported-by: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Tested-by: Jason Andryuk <jandryuk@gmail.com>
---
 Config.mk | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Jan Beulich June 23, 2023, 8:16 a.m. UTC | #1 
On 22.06.2023 17:30, Anthony PERARD wrote:
> --- a/Config.mk
> +++ b/Config.mk
> @@ -19,13 +19,13 @@ or       = $(if $(strip $(1)),$(1),$(if $(strip $(2)),$(2),$(if $(strip $(3)),$(
>  
>  -include $(XEN_ROOT)/.config
>  
> -XEN_COMPILE_ARCH    ?= $(shell uname -m | sed -e s/i.86/x86_32/ \
> +XEN_COMPILE_ARCH    ?= $(eval XEN_COMPILE_ARCH := $(shell uname -m | sed -e s/i.86/x86_32/ \
>                           -e s/i86pc/x86_32/ -e s/amd64/x86_64/ \
>                           -e s/armv7.*/arm32/ -e s/armv8.*/arm64/ \
> -                         -e s/aarch64/arm64/)
> +                         -e s/aarch64/arm64/))$(XEN_COMPILE_ARCH)

I'd like to suggest to wrap this differently, e.g.

XEN_COMPILE_ARCH    ?= $(eval XEN_COMPILE_ARCH := \
                         $(shell uname -m | \
                                 sed -e s/i.86/x86_32/ \
                                     -e s/i86pc/x86_32/ -e s/amd64/x86_64/ \
                                     -e s/armv7.*/arm32/ -e s/armv8.*/arm64/ \
                                     -e s/aarch64/arm64/) \
                         )$(XEN_COMPILE_ARCH)

>  XEN_TARGET_ARCH     ?= $(XEN_COMPILE_ARCH)
> -XEN_OS              ?= $(shell uname -s)
> +XEN_OS              ?= $(eval XEN_OS := $(shell uname -s))$(XEN_OS)

With these further uses of this same construct as in patch 4, is there
any chance of abstracting (part of, e.g. at least the rhs of the ?=)
the construct into a macro?

Jan
diff mbox series

Patch

diff --git a/Config.mk b/Config.mk
index c529b1ba19..5fbdbc4500 100644
--- a/Config.mk
+++ b/Config.mk
@@ -19,13 +19,13 @@  or       = $(if $(strip $(1)),$(1),$(if $(strip $(2)),$(2),$(if $(strip $(3)),$(
 
 -include $(XEN_ROOT)/.config
 
-XEN_COMPILE_ARCH    ?= $(shell uname -m | sed -e s/i.86/x86_32/ \
+XEN_COMPILE_ARCH    ?= $(eval XEN_COMPILE_ARCH := $(shell uname -m | sed -e s/i.86/x86_32/ \
                          -e s/i86pc/x86_32/ -e s/amd64/x86_64/ \
                          -e s/armv7.*/arm32/ -e s/armv8.*/arm64/ \
-                         -e s/aarch64/arm64/)
+                         -e s/aarch64/arm64/))$(XEN_COMPILE_ARCH)
 
 XEN_TARGET_ARCH     ?= $(XEN_COMPILE_ARCH)
-XEN_OS              ?= $(shell uname -s)
+XEN_OS              ?= $(eval XEN_OS := $(shell uname -s))$(XEN_OS)
 
 CONFIG_$(XEN_OS) := y