[PATCH v4 22/31] kconfig: add basic helper macros to scripts/Kconfig.include

[Masahiro Yamada]

Kconfig got text processing tools like we see in Make.  Add Kconfig
helper macros to scripts/Kconfig.include like we collect Makefile
macros in scripts/Kbuild.include.

Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Ulf Magnusson <ulfalizer@xxxxxxxxx>
---

Changes in v4:
  - source scripts/Kconfig.include
    from arch/x86/um/Kconfig since UML is special
  - Use { $(1); } for 'success' macro for better performance
  - Use -E instead of -c for 'cc-option' macro for better performance
  - Add 'if-success' macro

Changes in v3:
  - Move helpers to scripts/Kconfig.include

Changes in v2: None

 Kconfig                 |  2 ++
 MAINTAINERS             |  1 +
 arch/x86/um/Kconfig     |  2 ++
 scripts/Kconfig.include | 24 ++++++++++++++++++++++++
 4 files changed, 29 insertions(+)
 create mode 100644 scripts/Kconfig.include

diff --git a/Kconfig b/Kconfig
index 5b55d87..a90d9f9 100644
--- a/Kconfig
+++ b/Kconfig
@@ -7,4 +7,6 @@ mainmenu "Linux/$(ARCH) $(KERNELVERSION) Kernel Configuration"
 
 comment "Compiler: $(CC_VERSION_TEXT)"
 
+source "scripts/Kconfig.include"
+
 source "arch/$(SRCARCH)/Kconfig"
diff --git a/MAINTAINERS b/MAINTAINERS
index b7d7ae61..1667cee 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7634,6 +7634,7 @@ L:	linux-kbuild@xxxxxxxxxxxxxxx
 S:	Maintained
 F:	Documentation/kbuild/kconfig*
 F:	scripts/kconfig/
+F:	scripts/Kconfig.include
 
 KDUMP
 M:	Dave Young <dyoung@xxxxxxxxxx>
diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig
index a992f8e..9d529f2 100644
--- a/arch/x86/um/Kconfig
+++ b/arch/x86/um/Kconfig
@@ -3,6 +3,8 @@ mainmenu "User Mode Linux/$(SUBARCH) $(KERNELVERSION) Kernel Configuration"
 
 comment "Compiler: $(CC_VERSION_TEXT)"
 
+source "scripts/Kconfig.include"
+
 source "arch/um/Kconfig.common"
 
 menu "UML-specific options"
diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
new file mode 100644
index 0000000..b1502f4
--- /dev/null
+++ b/scripts/Kconfig.include
@@ -0,0 +1,24 @@
+# Kconfig helper macros
+
+# Convenient variables
+comma   := ,
+quote   := "
+squote  := '
+empty   :=
+space   := $(empty) $(empty)
+
+# $(if-success,<command>,<then-part>,<else-part>)
+# <then-part> if <command> exits with 0, <else-part> otherwise.
+if-success = $(shell, { $(1); } >/dev/null 2>&1 && echo "$(2)" || echo "$(3)")
+
+# $(success,<command>)
+# y if <command> exits with 0, n otherwise
+success = $(if-success, $(1),y,n)
+
+# $(cc-option,<flag>)
+# y if the compiler supports <flag>, n otherwise
+cc-option = $(success, $(CC) -Werror $(1) -E -x c /dev/null -o /dev/null)
+
+# $(ld-option,<flag>)
+# y if the linker supports <flag>, n otherwise
+ld-option = $(success, $(LD) -v $(1))
-- 
2.7.4