kbuild: fix asm-offset generation to work with clang

commit cf0c3e68aa81f992b0301f62e341b710d385bf68 upstream.

KBuild abuses the asm statement to write to a file and
clang chokes about these invalid asm statements. Hack it
even more by fooling this is actual valid asm code.

[masahiro:
 Import Jeroen's work for U-Boot:
 http://patchwork.ozlabs.org/patch/375026/
 Tweak sed script a little to avoid garbage '#' for GCC case, like
 #define NR_PAGEFLAGS 23 /* __NR_PAGEFLAGS       # */ ]

Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/kbuild.h b/include/linux/kbuild.h
index 22a7219..4e80f3a 100644 (file)
--- a/include/linux/kbuild.h
+++ b/include/linux/kbuild.h
@@ -2,14 +2,14 @@
 #define __LINUX_KBUILD_H
 
 #define DEFINE(sym, val) \
-        asm volatile("\n->" #sym " %0 " #val : : "i" (val))
+       asm volatile("\n.ascii \"->" #sym " %0 " #val "\"" : : "i" (val))
 
-#define BLANK() asm volatile("\n->" : : )
+#define BLANK() asm volatile("\n.ascii \"->\"" : : )
 
 #define OFFSET(sym, str, mem) \
        DEFINE(sym, offsetof(struct str, mem))
 
 #define COMMENT(x) \
-       asm volatile("\n->#" x)
+       asm volatile("\n.ascii \"->#" x "\"")
 
 #endif

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index fd940cc..4e02d51 100644 (file)
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -413,10 +413,14 @@ cmd_xzmisc = (cat $(filter-out FORCE,$^) | \
 # ---------------------------------------------------------------------------
 
 # Default sed regexp - multiline due to syntax constraints
+#
+# Use [:space:] because LLVM's integrated assembler inserts <tab> around
+# the .ascii directive whereas GCC keeps the <space> as-is.
 define sed-offsets
-       "/^->/{s:->#\(.*\):/* \1 */:; \
+       's:^[[:space:]]*\.ascii[[:space:]]*"\(.*\)".*:\1:; \
+       /^->/{s:->#\(.*\):/* \1 */:; \
        s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
-       s:->::; p;}"
+       s:->::; p;}'
 endef
 
 # Use filechk to avoid rebuilds when a header changes, but the resulting file