[PATCH v2 4/7] kbuild: fix asm-offset generation to work with clang

Thomas Huth
2020-10-01T07:23:00Z

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.

This is an adaption of the Linux kernel commit cf0c3e68aa81f992b0
which in turn is based on a patch for the U-Boot:
http://patchwork.ozlabs.org/patch/375026/

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
lib/kbuild.h | 6 +++---
scripts/asm-offsets.mak | 5 +++--
2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/lib/kbuild.h b/lib/kbuild.h
index ab99db6..79644e5 100644
--- a/lib/kbuild.h
+++ b/lib/kbuild.h
@@ -1,8 +1,8 @@
#ifndef _KBUILD_H_
#define _KBUILD_H_
#define DEFINE(sym, val) \
- asm volatile("\n->" #sym " %0 " #val : : "i" (val))
+ asm volatile("\n.ascii \"->" #sym " %0 " #val "\"" : : "i" (val))
#define OFFSET(sym, str, mem) DEFINE(sym, offsetof(struct str, mem))
-#define COMMENT(x) asm volatile("\n->#" x)
-#define BLANK() asm volatile("\n->" : : )
+#define COMMENT(x) asm volatile("\n.ascii \"->#" x "\"")
+#define BLANK() asm volatile("\n.ascii \"->\"" : : )
#endif
diff --git a/scripts/asm-offsets.mak b/scripts/asm-offsets.mak
index b35da09..7b64162 100644
--- a/scripts/asm-offsets.mak
+++ b/scripts/asm-offsets.mak
@@ -8,10 +8,11 @@
#

define sed-y
- "/^->/{s:->#\(.*\):/* \1 */:; \
+ 's:^[[:space:]]*\.ascii[[:space:]]*"\(.*\)".*:\1:; \
+ /^->/{s:->#\(.*\):/* \1 */:; \
s:^->\([^ ]*\) [\$$#]*\([-0-9]*\) \(.*\):#define \1 \2 /* \3 */:; \
s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
- s:->::; p;}"
+ s:->::; p;}'
endef

define make_asm_offsets
--
2.18.2