[Xen-devel] [PATCH v2] asm-offsets: encode magic asm-offset runes as strings.

[Tim Deegan <tim@xxxxxxx>]

Newer versions of clang attempt to parse inline assembler even when
not asked to assemble it.  Wrap our not-for-assembly runes as strings
of the form ``.ascii "==>MAGIC RUNES<=="'' so clang doesn't choke on
them.

While we're at it, assemble more of the final output line in the C
file, to make the sed expression shorter.

Reported-by: Julien Grall <julien.grall@xxxxxxxxxx>
Suggested-by: Jan Beulich <JBeulich@xxxxxxxx>
Signed-off-by: Tim Deegan <tim@xxxxxxx>
---
v2: make up the '#define' in the C source rather then in sed.
Not quite as neat as I'd hoped: need to match an extra space
to stop the second sed expression eating the # in #define.

diff --git a/xen/Makefile b/xen/Makefile
index 79fa8f2..afbc962 100644
--- a/xen/Makefile
+++ b/xen/Makefile
@@ -150,7 +150,7 @@ include/asm-$(TARGET_ARCH)/asm-offsets.h: 
arch/$(TARGET_ARCH)/asm-offsets.s
          echo "#ifndef __ASM_OFFSETS_H__"; \
          echo "#define __ASM_OFFSETS_H__"; \
          echo ""; \
-         sed -ne "/^->/{s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 
/* \3 */:; s:->::; p;}"; \
+         sed -rne "/==>/{s:.*==>(.*)<==.*:\1:; s: [\$$#]: :; p;}"; \
          echo ""; \
          echo "#endif") <$< >$@
 
diff --git a/xen/arch/arm/arm32/asm-offsets.c b/xen/arch/arm/arm32/asm-offsets.c
index ac628c0..cd1dff7 100644
--- a/xen/arch/arm/arm32/asm-offsets.c
+++ b/xen/arch/arm/arm32/asm-offsets.c
@@ -13,11 +13,12 @@
 #include <asm/current.h>
 #include <asm/procinfo.h>
 
-#define DEFINE(_sym, _val) \
-    __asm__ __volatile__ ( "\n->" #_sym " %0 " #_val : : "i" (_val) )
-#define BLANK() \
-    __asm__ __volatile__ ( "\n->" : : )
-#define OFFSET(_sym, _str, _mem) \
+#define DEFINE(_sym, _val)                                                 \
+    asm volatile ("\n.ascii\"==>#define " #_sym " %0 /* " #_val " */<==\"" \
+                  : : "i" (_val) )
+#define BLANK()                                                            \
+    asm volatile ( "\n.ascii\"==><==\"" : : )
+#define OFFSET(_sym, _str, _mem)                                           \
     DEFINE(_sym, offsetof(_str, _mem));
 
 void __dummy__(void)
diff --git a/xen/arch/arm/arm64/asm-offsets.c b/xen/arch/arm/arm64/asm-offsets.c
index d7572fa..a3ce816 100644
--- a/xen/arch/arm/arm64/asm-offsets.c
+++ b/xen/arch/arm/arm64/asm-offsets.c
@@ -12,11 +12,12 @@
 #include <public/xen.h>
 #include <asm/current.h>
 
-#define DEFINE(_sym, _val) \
-    __asm__ __volatile__ ( "\n->" #_sym " %0 " #_val : : "i" (_val) )
-#define BLANK() \
-    __asm__ __volatile__ ( "\n->" : : )
-#define OFFSET(_sym, _str, _mem) \
+#define DEFINE(_sym, _val)                                                 \
+    asm volatile ("\n.ascii\"==>#define " #_sym " %0 /* " #_val " */<==\"" \
+                  : : "i" (_val) )
+#define BLANK()                                                            \
+    asm volatile ( "\n.ascii\"==><==\"" : : )
+#define OFFSET(_sym, _str, _mem)                                           \
     DEFINE(_sym, offsetof(_str, _mem));
 
 void __dummy__(void)
diff --git a/xen/arch/x86/x86_64/asm-offsets.c 
b/xen/arch/x86/x86_64/asm-offsets.c
index b0098b3..9acb648 100644
--- a/xen/arch/x86/x86_64/asm-offsets.c
+++ b/xen/arch/x86/x86_64/asm-offsets.c
@@ -14,11 +14,12 @@
 #include <asm/hardirq.h>
 #include <xen/multiboot.h>
 
-#define DEFINE(_sym, _val) \
-    __asm__ __volatile__ ( "\n->" #_sym " %0 " #_val : : "i" (_val) )
-#define BLANK() \
-    __asm__ __volatile__ ( "\n->" : : )
-#define OFFSET(_sym, _str, _mem) \
+#define DEFINE(_sym, _val)                                                 \
+    asm volatile ("\n.ascii\"==>#define " #_sym " %0 /* " #_val " */<==\"" \
+                  : : "i" (_val) )
+#define BLANK()                                                            \
+    asm volatile ( "\n.ascii\"==><==\"" : : )
+#define OFFSET(_sym, _str, _mem)                                           \
     DEFINE(_sym, offsetof(_str, _mem));
 
 void __dummy__(void)

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