[v2,1/4] Add declare_object_symbol_alias for assembly codes (BZ #28128)
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Commit Message
From: "H.J. Lu" <hjl.tools@gmail.com>
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.
---
include/libc-symbols.h | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
Comments
On 2022-05-12, Adhemerval Zanella wrote:
>From: "H.J. Lu" <hjl.tools@gmail.com>
>
>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.
Interesting. clang -E can expand
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101613
correctly.
Reviewed-by: Fangrui Song <maskray@google.com>
>---
> 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) \
>--
>2.34.1
>
@@ -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) \