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-rw-r--r--sysdeps/generic/libc-symver.h56
1 files changed, 53 insertions, 3 deletions
diff --git a/sysdeps/generic/libc-symver.h b/sysdeps/generic/libc-symver.h
index 11c77ae1cd..69d147e2a8 100644
--- a/sysdeps/generic/libc-symver.h
+++ b/sysdeps/generic/libc-symver.h
@@ -22,17 +22,67 @@
 #ifndef _LIBC_SYMVER_H
 #define _LIBC_SYMVER_H 1
 
+#include <config.h>
+
 /* Use symbol_version_reference to specify the version a symbol
    reference should link to.  Use symbol_version or
    default_symbol_version for the definition of a versioned symbol.
    The difference is that the latter is a no-op in non-shared
-   builds.  */
+   builds.
+
+   _set_symbol_version is similar to symbol_version_reference, except
+   that this macro expects the name and symbol version as a single
+   string or token sequence, with an @ or @@ separator.  (A string is
+   used in C mode and a token sequence in assembler mode.)
+   _set_symbol_version only be used for definitions because it may
+   introduce an alias symbol that would not be globally unique for
+   mere references.  The _set_symbol_version macro is used to define
+   default_symbol_version and compat_symbol.  */
+
 #ifdef __ASSEMBLER__
 # define symbol_version_reference(real, name, version) \
      .symver real, name##@##version
-#else  /* !__ASSEMBLER__ */
+#else
 # define symbol_version_reference(real, name, version) \
   __asm__ (".symver " #real "," #name "@" #version)
-#endif
+#endif  /* !__ASSEMBLER__ */
+
+#if SYMVER_NEEDS_ALIAS
+/* If the assembler cannot support multiple versions for the same
+   symbol, introduce __SInnn_ aliases to which the symbol version is
+   attached.  */
+# define __symbol_version_unique_concat(x, y) __SI ## x ## _ ## y
+# define _symbol_version_unique_concat(x, y) \
+  __symbol_version_unique_concat (x, y)
+# define _symbol_version_unique_alias(name) \
+  _symbol_version_unique_concat (name, __COUNTER__)
+# ifdef __ASSEMBLER__
+#  define _set_symbol_version_2(real, alias, name_version) \
+  .globl alias ASM_LINE_SEP                                \
+  .equiv alias, real ASM_LINE_SEP                          \
+  .symver alias, name_version
+# else
+#  define _set_symbol_version_2(real, alias, name_version) \
+  __asm__ (".globl " #alias "\n\t"                         \
+           ".equiv " #alias ", " #real "\n\t"              \
+           ".symver " #alias "," name_version)
+# endif
+# define _set_symbol_version_1(real, alias, name_version) \
+  _set_symbol_version_2 (real, alias, name_version)
+/* REAL must be globally unique, so that the counter also produces
+   globally unique symbols.  */
+# define _set_symbol_version(real, name_version)                   \
+  _set_symbol_version_1 (real, _symbol_version_unique_alias (real), \
+                               name_version)
+# else  /* !SYMVER_NEEDS_ALIAS */
+# ifdef __ASSEMBLER__
+#  define _set_symbol_version(real, name_version) \
+  .symver real, name_version
+# else
+#  define _set_symbol_version(real, name_version) \
+  __asm__ (".symver " #real "," name_version)
+# endif
+#endif  /* !SYMVER_NEEDS_ALIAS */
+
 
 #endif /* _LIBC_SYMVER_H */