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commit bdc543e338281da051b3dc06eae96c330a485ce6
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Thu Mar 16 09:15:57 2017 -0300
sparc: Fix .udiv plt on libc
With the removal of divdi3 object from sparcv9-linux-gnu build, its
definition came from libgcc and its functions internall calls .udiv.
Since glibc also exports these symbols for compatibility reasons, it
will end up creating PLT calls internally in libc.so.
To avoid it, this patch uses the linker option --wrap to replace all
the internal libc.so .udiv calls to the wrapper __wrap_.udiv. Along
with strong alias in the udiv implementations, it makes linker do
local calls.
Checked on sparcv9-linux-gnu.
* sysdeps/sparc/sparc32/Makefile (libc.so-gnulib): New rule.
* sysdeps/sparc/sparc32/sparcv8/udiv.S (.udiv): Make a strong_alias
to __wrap_.udiv.
* sysdeps/sparc/sparc32/sparcv9/udiv.S (.udiv): Likewise.
* sysdeps/sparc/sparc32/udiv.S (.udiv): Likewise.
---
sysdeps/sparc/sparc32/Makefile | 6 ++++++
sysdeps/sparc/sparc32/sparcv8/udiv.S | 1 +
sysdeps/sparc/sparc32/sparcv9/udiv.S | 1 +
sysdeps/sparc/sparc32/udiv.S | 1 +
4 files changed, 9 insertions(+)
--- a/sysdeps/sparc/sparc32/Makefile
+++ b/sysdeps/sparc/sparc32/Makefile
@@ -47,3 +47,9 @@
mv -f $@-tmp $@
sysdep-realclean := $(sysdep-realclean) $(divrem:%=sysdeps/sparc/sparc32/%.S)
+
+# libgcc __divdi3 and __moddi3 uses .udiv and since it is also exported by
+# libc.so linker will create PLTs for the symbol. To avoid it we strong alias
+# the exported libc one to __wrap_.udiv and use linker option --wrap to make any
+# call to .udiv to call the wrapper symbol.
+libc.so-gnulib += -Wl,--wrap=.udiv
--- a/sysdeps/sparc/sparc32/sparcv8/udiv.S
+++ b/sysdeps/sparc/sparc32/sparcv8/udiv.S
@@ -13,3 +13,4 @@
udiv %o0, %o1, %o0
END(.udiv)
+strong_alias (.udiv, __wrap_.udiv)
--- a/sysdeps/sparc/sparc32/sparcv9/udiv.S
+++ b/sysdeps/sparc/sparc32/sparcv9/udiv.S
@@ -15,3 +15,4 @@
udiv %o0, %o1, %o0
END(.udiv)
+strong_alias (.udiv, __wrap_.udiv)
--- a/sysdeps/sparc/sparc32/udiv.S
+++ b/sysdeps/sparc/sparc32/udiv.S
@@ -344,3 +344,4 @@
mov %o2, %o0
END(.udiv)
+strong_alias (.udiv, __wrap_.udiv)
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