[PATCH 10/20] Kbuild, lto: add ld-version and ld-ifversion macros

[Andi Kleen]

From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

To check the linker version. Used by the LTO makefile.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
 Documentation/kbuild/makefiles.txt | 10 ++++++++++
 scripts/Kbuild.include             |  9 +++++++++
 scripts/ld-version.sh              |  8 ++++++++
 3 files changed, 27 insertions(+)
 create mode 100755 scripts/ld-version.sh

diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index d567a7c..40d51f3 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -595,6 +595,16 @@ more details, with real examples.
 		#Makefile
 		LDFLAGS_vmlinux += $(call ld-option, -X)
 
+    ld-version
+	ld-version returns the full version number of $(LD), for three
+	number binutils versions, like the Linux binutils
+
+    ld-ifversion
+	Check the version number of the $(LD) linker in an if.
+
+	Example:
+		#Makefile.lto
+		ifeq ($(call ld-ifversion,-ge,22710001,y),y)
 
 === 4 Host Program support
 
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 547e15d..93a0da2 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -155,6 +155,15 @@ ld-option = $(call try-run,\
 # Important: no spaces around options
 ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2))
 
+# ld-version
+# Usage: $(call ld-version)
+# Note this is mainly for HJ Lu's 3 number binutil versions
+ld-version = $(shell $(LD) --version | $(srctree)/scripts/ld-version.sh)
+
+# ld-ifversion
+# Usage:  $(call ld-ifversion, -ge, 22252, y)
+ld-ifversion = $(shell [ $(call ld-version) $(1) $(2) ] && echo $(3))
+
 ######
 
 ###
diff --git a/scripts/ld-version.sh b/scripts/ld-version.sh
new file mode 100755
index 0000000..198580d
--- /dev/null
+++ b/scripts/ld-version.sh
@@ -0,0 +1,8 @@
+#!/usr/bin/awk -f
+# extract linker version number from stdin and turn into single number
+	{
+	gsub(".*)", "");
+	split($1,a, ".");
+	print a[1]*10000000 + a[2]*100000 + a[3]*10000 + a[4]*100 + a[5];
+	exit
+	}
-- 
1.8.5.2

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