[glibc] Add declare_object_symbol_alias for assembly codes (BZ #28128)

[Adhemerval Zanella <azanella@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=111254f3e1e1a7ae5c2eda7cebc98f93a61d417c

commit 111254f3e1e1a7ae5c2eda7cebc98f93a61d417c
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Wed Apr 6 10:06:37 2022 -0300

    Add declare_object_symbol_alias for assembly codes (BZ #28128)
    
    There are 2 problems in:
    
     #define declare_symbol_alias(symbol, original, type, size) \
      declare_symbol_alias_1 (symbol, original, type, size)
     #ifdef __ASSEMBLER__
     # define declare_symbol_alias_1(symbol, original, type, size) \
       strong_alias (original, symbol); \
       .type C_SYMBOL_NAME (symbol), %##type; \
       .size C_SYMBOL_NAME (symbol), size
    
    1. .type and .size are substituted by arguments.
    2. %##type is expanded to "% type" due to the GCC bug:
    
    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101613
    
    But assembler doesn't support "% type".
    
    Workaround BZ #28128 by
    
    1. Don't define declare_symbol_alias for assembly codes.
    2. Define declare_object_symbol_alias for assembly codes.
    
    Reviewed-by: Fangrui Song <maskray@google.com>

Diff:
---
 include/libc-symbols.h | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/include/libc-symbols.h b/include/libc-symbols.h
index 662bd118b1..4bb3d8c7ba 100644
--- a/include/libc-symbols.h
+++ b/include/libc-symbols.h
@@ -324,14 +324,16 @@ for linking")
    This is only necessary when defining something in assembly, or playing
    funny alias games where the size should be other than what the compiler
    thinks it is.  */
-#define declare_symbol_alias(symbol, original, type, size) \
-  declare_symbol_alias_1 (symbol, original, type, size)
 #ifdef __ASSEMBLER__
-# define declare_symbol_alias_1(symbol, original, type, size) \
-   strong_alias (original, symbol); \
-   .type C_SYMBOL_NAME (symbol), %##type; \
-   .size C_SYMBOL_NAME (symbol), size
+# define declare_object_symbol_alias(symbol, original, size) \
+  declare_object_symbol_alias_1 (symbol, original, size)
+# define declare_object_symbol_alias_1(symbol, original, s_size) \
+   strong_alias (original, symbol) ASM_LINE_SEP \
+   .type C_SYMBOL_NAME (symbol), %object ASM_LINE_SEP \
+   .size C_SYMBOL_NAME (symbol), s_size ASM_LINE_SEP
 #else /* Not __ASSEMBLER__.  */
+# define declare_symbol_alias(symbol, original, type, size) \
+  declare_symbol_alias_1 (symbol, original, type, size)
 # define declare_symbol_alias_1(symbol, original, type, size) \
    asm (".globl " __SYMBOL_PREFIX #symbol \
 	"\n\t" declare_symbol_alias_1_alias (symbol, original) \