3a6c85abcb
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
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| .. | ||
| boot0 | ||
| boot0sio | ||
| boot2 | ||
| btx | ||
| cdboot | ||
| common | ||
| gptboot | ||
| gptzfsboot | ||
| isoboot | ||
| libfirewire | ||
| libi386 | ||
| loader | ||
| loader_4th | ||
| loader_lua | ||
| loader_simp | ||
| mbr | ||
| pmbr | ||
| pxeldr | ||
| zfsboot | ||
| boot.ldscript | ||
| Makefile | ||
| Makefile.inc | ||