[Buildroot] [PATCH v4 03/15] package/uclibc: remove asm constraint

[Giulio Benetti]

From: Romain Naour <romain.naour at gmail.com>

uClibc-ng don't build with gcc 9.1 [1] due to a new check that
"catch illegal asm constraint usage" [2].

gcc 9.1 print this error:
"invalid hard register usage between earlyclobber operand and input operand"

The asm constraint is present in uClibc since it support sparc (back in 2002)[3].

Note: There is no such constraint is Glibc counterpart code [4].

[1] https://gitlab.com/kubu93/toolchains-builder/-/jobs/205435757
[2] https://github.com/gcc-mirror/gcc/commit/b782636f28f5c378897c238081d28d7a4a6ca578
[3] https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/commit/?id=3b6d086531102b6d09ce852feb1e370d5dca3ce9
[4] https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/sparc/sysdep.h;h=981b2a26b7a91093f821c97876e55bc4be2d9f8a;hb=HEAD

Signed-off-by: Romain Naour <romain.naour at gmail.com>
Cc: Waldemar Brodkorb <wbx at openadk.org>
Signed-off-by: Giulio Benetti <giulio.benetti at micronovasrl.com>
---
I did not fully analyze the asm code to understand why the constraint is present.
I lightly tested using qemu_sparc_ss10_defconfig.
Any help is welcome(Romain)
---
 ...arc-syscalls.h-remove-asm-constraint.patch | 46 +++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 package/uclibc/0003-RFC-sparc-syscalls.h-remove-asm-constraint.patch

diff --git a/package/uclibc/0003-RFC-sparc-syscalls.h-remove-asm-constraint.patch b/package/uclibc/0003-RFC-sparc-syscalls.h-remove-asm-constraint.patch
new file mode 100644
index 0000000000..050dc573b0
--- /dev/null
+++ b/package/uclibc/0003-RFC-sparc-syscalls.h-remove-asm-constraint.patch
@@ -0,0 +1,46 @@
+From 1854c332efa0ed5b9140d8df2a983625a1e2d9ef Mon Sep 17 00:00:00 2001
+From: Romain Naour <romain.naour at gmail.com>
+Date: Sun, 5 May 2019 10:56:30 +0200
+Subject: [PATCH] [RFC] sparc: syscalls.h: remove asm constraint
+
+uClibc-ng don't build with gcc 9.1 [1] due to a new check that
+"catch illegal asm constraint usage" [2].
+
+gcc 9.1 print this error:
+"invalid hard register usage between earlyclobber operand and input operand"
+
+The asm constraint is present in uClibc since it support sparc (back in 2002)[3].
+
+Note: There is no such constraint is Glibc counterpart code [4].
+
+[1] https://gitlab.com/kubu93/toolchains-builder/-/jobs/205435757
+[2] https://github.com/gcc-mirror/gcc/commit/b782636f28f5c378897c238081d28d7a4a6ca578
+[3] https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/commit/?id=3b6d086531102b6d09ce852feb1e370d5dca3ce9
+[4] https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/sparc/sysdep.h;h=981b2a26b7a91093f821c97876e55bc4be2d9f8a;hb=HEAD
+
+Signed-off-by: Romain Naour <romain.naour at gmail.com>
+Cc: Waldemar Brodkorb <wbx at openadk.org>
+---
+I did not fully analyze the asm code to understand why the constraint is present.
+I lightly tested using qemu_sparc_ss10_defconfig.
+Any help is welcome :)
+---
+ libc/sysdeps/linux/sparc/bits/syscalls.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/libc/sysdeps/linux/sparc/bits/syscalls.h b/libc/sysdeps/linux/sparc/bits/syscalls.h
+index 75af7a1573..e52ab98466 100644
+--- a/libc/sysdeps/linux/sparc/bits/syscalls.h
++++ b/libc/sysdeps/linux/sparc/bits/syscalls.h
+@@ -33,7 +33,7 @@
+             register long __g1 __asm__("g1") = sys_num;     \
+             LOAD_ARGS_##nr(args)                            \
+             __asm__ __volatile__( __SYSCALL_STRING          \
+-                : "=r" (__res), "=&r" (__o0)                \
++                : "=r" (__res), "=r" (__o0)                 \
+                 : "1" (__o0) ASM_ARGS_##nr, "r" (__g1)     \
+                 : __SYSCALL_CLOBBERS );                                   \
+         }                                                   \
+-- 
+2.14.5
+
-- 
2.17.1