Author: emaste
Date: Thu Aug 15 14:54:18 2019
New Revision: 351073
URL: https://svnweb.freebsd.org/changeset/base/351073
Log:
stand: remove CLANG_NO_IAS from boot2
Many components under stand/ had CLANG_NO_IAS added when Clang's
Integrated Assembler (IAS) did not handle .codeNN directives. Clang
gained support quite some time ago, and we can now build stand/ with
IAS. In most cases IAS- and GNU as-assembled boot components were
identical, and CLANG_NO_IAS was already removed from other components.
Clang IAS produces different output for some components, including
boot2, so CLANG_NO_IAS was not previously removed for those.
In the case of boot2 the difference is that IAS produces a larger
encoding for one instruction (the testb at the beginning of read).
GNU as produces:
2e f6 06 b0 08 80
while IAS includes an address size override prefix (67) and produces:
2e 67 f6 05 b3 08 00 00 80
This results in three fewer NOPs elsewhere in boot2 but no functional
change, so switch to IAS for boot2.
(We can separately pursue improved 16-bit IAS support with the LLVM
developers.)
Sponsored by: The FreeBSD Foundation
Modified:
head/stand/i386/boot2/Makefile
Modified: head/stand/i386/boot2/Makefile
==============================================================================
--- head/stand/i386/boot2/Makefile Thu Aug 15 14:11:11 2019
(r351072)
+++ head/stand/i386/boot2/Makefile Thu Aug 15 14:54:18 2019
(r351073)
@@ -91,6 +91,3 @@ boot2.h: boot1.out
REL1=`printf "%d" ${REL1}` > ${.TARGET}
.include <bsd.prog.mk>
-
-# XXX: clang integrated-as doesn't grok .codeNN directives yet
-CFLAGS.boot1.S= ${CLANG_NO_IAS}
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