Clang understands the GCCism in use here, but still complains that sp is
unintialised. In such cases, resort to the older version of this code, which
directly reads %rsp into the temporary variable.
Note that we still keep the GCCism in the default case, as it causes GCC to
create rather better assembly.
Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
---
CC: Jan Beulich <jbeul...@suse.com>
---
xen/include/asm-x86/current.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/xen/include/asm-x86/current.h b/xen/include/asm-x86/current.h
index f011d2d..15b99ff 100644
--- a/xen/include/asm-x86/current.h
+++ b/xen/include/asm-x86/current.h
@@ -47,7 +47,13 @@ struct cpu_info {
static inline struct cpu_info *get_cpu_info(void)
{
+#ifdef __clang__
+ /* Clang complains that sp in the else case is not initialised. */
+ unsigned long sp;
+ asm ( "mov %%rsp, %0" : "=r" (sp) );
+#else
register unsigned long sp asm("rsp");
+#endif
return (struct cpu_info *)((sp & ~(STACK_SIZE-1)) + STACK_SIZE) - 1;
}
--
2.1.4
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