[glibc/azanella/clang] string: Use asm alias instead of symbol redirections for stpcpy and mempcpy
Adhemerval Zanella
azanella@sourceware.org
Tue Apr 2 15:52:56 GMT 2024
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=54c56fb6716cf641a6a3d05a0daf017233c255a1
commit 54c56fb6716cf641a6a3d05a0daf017233c255a1
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Tue Mar 15 08:41:43 2022 -0300
string: Use asm alias instead of symbol redirections for stpcpy and mempcpy
Commit 939da411433 added symbols redirections to handle ISO C
namespace, however some compiler does not support to redeclare the
function prototype. Moving these defintions to exported header
it not a good practice (it exposes a internal implementation and
it would require to add macros to define it only internally).
Instead this patch replaces the symbol redirections by direct asm
aliases, as done to handle libcall generation done by compiler on
some loop optimizations. The only issue is sparc binutils generates
an extra __mempcpy plt not called anywhere in the code, which indicates
a binutils issue (this is added in the localplt.data for now).
Checked on all affected ABIs.
Diff:
---
include/string.h | 4 ++--
sysdeps/unix/sysv/linux/sparc/sparc32/localplt.data | 3 +++
sysdeps/unix/sysv/linux/sparc/sparc64/localplt.data | 3 +++
3 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/include/string.h b/include/string.h
index 3b4c6007d7..082865caad 100644
--- a/include/string.h
+++ b/include/string.h
@@ -179,8 +179,8 @@ extern __typeof (strsep) strsep attribute_hidden;
&& !defined NO_MEMPCPY_STPCPY_REDIRECT
/* Redirect calls to __builtin_mempcpy and __builtin_stpcpy to call
__mempcpy and __stpcpy if not inlined. */
-extern __typeof (mempcpy) mempcpy __asm__ ("__mempcpy");
-extern __typeof (stpcpy) stpcpy __asm__ ("__stpcpy");
+__asm__ ("mempcpy = __mempcpy");
+__asm__ ("stpcpy = __stpcpy");
#endif
extern void *__memcpy_chk (void *__restrict __dest,
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/localplt.data b/sysdeps/unix/sysv/linux/sparc/sparc32/localplt.data
index b5fc6d9c3a..327276d9c2 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc32/localplt.data
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/localplt.data
@@ -17,4 +17,7 @@ libc.so: calloc
libc.so: free
libc.so: malloc
libc.so: realloc
+# Unreferenced PLT created by the symbols aliases used to redirect
+# the compiler generated mempcpy/stpcyp calls done by builtin usage.
+libc.so: __mempcpy
libm.so: matherr
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/localplt.data b/sysdeps/unix/sysv/linux/sparc/sparc64/localplt.data
index 15c0f8ccf7..e7ab61dcbe 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/localplt.data
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/localplt.data
@@ -17,4 +17,7 @@ libc.so: calloc
libc.so: free
libc.so: malloc
libc.so: realloc
+# Unreferenced PLT created by the symbols aliases used to redirect
+# the compiler generated mempcpy/stpcyp calls done by builtin usage.
+libc.so: __mempcpy
libm.so: matherr
More information about the Glibc-cvs
mailing list