kbuild: add test-{ge,gt,le,lt} macros

GNU Make 4.4 introduced $(intcmp ...), which is useful to compare two
integers without forking a new process.

Add test-{ge,gt,le,lt} macros, which work more efficiently with GNU
Make >= 4.4. For older Make versions, they fall back to the 'test'
shell command.

The first two parameters to $(intcmp ...) must not be empty. To avoid
the syntax error, I appended '0' to them. Fortunately, '00' is treated
as '0'. This is needed because CONFIG options may expand to an empty
string when the kernel configuration is not included.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com> # RISC-V
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

1 files changed, 16 insertions, 0 deletions

diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index cbe28744637b..3be7c2d75667 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -12,6 +12,22 @@ space_escape := _-_SPACE_-_
 pound := \#
 
 ###
+# Comparison macros.
+# Usage: $(call test-lt, $(CONFIG_LLD_VERSION), 150000)
+#
+# Use $(intcmp ...) if supported. (Make >= 4.4)
+# Otherwise, fall back to the 'test' shell command.
+ifeq ($(intcmp 1,0,,,y),y)
+test-ge = $(intcmp $(strip $1)0, $(strip $2)0,,y,y)
+test-gt = $(intcmp $(strip $1)0, $(strip $2)0,,,y)
+else
+test-ge = $(shell test $(strip $1)0 -ge $(strip $2)0 && echo y)
+test-gt = $(shell test $(strip $1)0 -gt $(strip $2)0 && echo y)
+endif
+test-le = $(call test-ge, $2, $1)
+test-lt = $(call test-gt, $2, $1)
+
+###
 # Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
 dot-target = $(dir $@).$(notdir $@)