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authorDenis Vlasenko <vda.linux@googlemail.com>2008-11-22 14:24:04 +0000
committerDenis Vlasenko <vda.linux@googlemail.com>2008-11-22 14:24:04 +0000
commit1e950c61e51838680f35317669376e40d69bc6c6 (patch)
tree22afbe787a9a5b9d6d0240404078653c41cc6ef4
parentc33ce133b9da9236fffd19d72d6b4d2ca63bfa2a (diff)
libc-symbols: improve comments and make macros a bit more readable.
no code changes
-rw-r--r--include/libc-symbols.h291
1 files changed, 157 insertions, 134 deletions
diff --git a/include/libc-symbols.h b/include/libc-symbols.h
index 3f29b9463..34be37c5d 100644
--- a/include/libc-symbols.h
+++ b/include/libc-symbols.h
@@ -200,34 +200,34 @@
# ifdef HAVE_ASM_SET_DIRECTIVE
# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define strong_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original) ASM_LINE_SEP \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP \
- .set C_SYMBOL_DOT_NAME (alias),C_SYMBOL_DOT_NAME (original)
-# define strong_data_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
+# define strong_alias(original, alias) \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ .set C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original) ASM_LINE_SEP \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \
+ .set C_SYMBOL_DOT_NAME(alias),C_SYMBOL_DOT_NAME(original)
+# define strong_data_alias(original, alias) \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ .set C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original)
# else
-# define strong_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
+# define strong_alias(original, alias) \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ .set C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original)
# define strong_data_alias(original, alias) strong_alias(original, alias)
# endif
# else
# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define strong_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
-# define strong_data_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
+# define strong_alias(original, alias) \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ C_SYMBOL_NAME(alias) = C_SYMBOL_NAME(original) ASM_LINE_SEP \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \
+ C_SYMBOL_DOT_NAME(alias) = C_SYMBOL_DOT_NAME(original)
+# define strong_data_alias(original, alias) \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ C_SYMBOL_NAME(alias) = C_SYMBOL_NAME(original)
# else
-# define strong_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
+# define strong_alias(original, alias) \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ C_SYMBOL_NAME(alias) = C_SYMBOL_NAME(original)
# define strong_data_alias(original, alias) strong_alias(original, alias)
# endif
# endif
@@ -235,45 +235,45 @@
# ifdef HAVE_WEAK_SYMBOLS
# ifdef HAVE_ASM_WEAKEXT_DIRECTIVE
# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define weak_alias(original, alias) \
- .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original) ASM_LINE_SEP \
- .weakext C_SYMBOL_DOT_NAME (alias), C_SYMBOL_DOT_NAME (original)
+# define weak_alias(original, alias) \
+ .weakext C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original) ASM_LINE_SEP \
+ .weakext C_SYMBOL_DOT_NAME(alias),C_SYMBOL_DOT_NAME(original)
# else
-# define weak_alias(original, alias) \
- .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original)
+# define weak_alias(original, alias) \
+ .weakext C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original)
# endif
-# define weak_extern(symbol) \
- .weakext C_SYMBOL_NAME (symbol)
+# define weak_extern(symbol) \
+ .weakext C_SYMBOL_NAME(symbol)
# else /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
# ifdef HAVE_ASM_SET_DIRECTIVE
# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define weak_alias(original, alias) \
- .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- .set C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original) ASM_LINE_SEP \
- .weak C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP \
- .set C_SYMBOL_DOT_NAME (alias), C_SYMBOL_DOT_NAME (original)
+# define weak_alias(original, alias) \
+ .weak C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ .set C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original) ASM_LINE_SEP \
+ .weak C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \
+ .set C_SYMBOL_DOT_NAME(alias),C_SYMBOL_DOT_NAME(original)
# else
-# define weak_alias(original, alias) \
- .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- .set C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original)
+# define weak_alias(original, alias) \
+ .weak C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ .set C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original)
# endif
# else /* ! HAVE_ASM_SET_DIRECTIVE */
# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define weak_alias(original, alias) \
- .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP \
- .weak C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
+# define weak_alias(original, alias) \
+ .weak C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ C_SYMBOL_NAME(alias) = C_SYMBOL_NAME(original) ASM_LINE_SEP \
+ .weak C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \
+ C_SYMBOL_DOT_NAME(alias) = C_SYMBOL_DOT_NAME(original)
# else
-# define weak_alias(original, alias) \
- .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
+# define weak_alias(original, alias) \
+ .weak C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ C_SYMBOL_NAME(alias) = C_SYMBOL_NAME(original)
# endif
# endif
-# define weak_extern(symbol) \
- .weak C_SYMBOL_NAME (symbol)
+# define weak_extern(symbol) \
+ .weak C_SYMBOL_NAME(symbol)
# endif /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
@@ -285,6 +285,7 @@
#endif /* __ASSEMBLER__ */
+
/* On some platforms we can make internal function calls (i.e., calls of
functions not exported) a bit faster by using a different calling
convention. */
@@ -292,10 +293,12 @@
# define internal_function /* empty */
#endif
+
/* We want the .gnu.warning.SYMBOL section to be unallocated. */
#define __make_section_unallocated(section_string) \
__asm__ (".section " section_string "\n\t.previous");
+
/* Tacking on "\n#APP\n\t#" to the section name makes gcc put it's bogus
section attributes on what looks like a comment to the assembler. */
#ifdef __sparc__ /* HAVE_SECTION_QUOTES */
@@ -304,6 +307,7 @@
# define __sec_comment "\n#APP\n\t#"
#endif
+
/* When a reference to SYMBOL is encountered, the linker will emit a
warning message MSG. */
#define link_warning(symbol, msg) \
@@ -317,8 +321,7 @@
#ifdef SHARED
# define INTUSE(name) name##_internal
# define INTDEF(name) strong_alias (name, name##_internal)
-# define INTVARDEF(name) \
- _INTVARDEF (name, name##_internal)
+# define INTVARDEF(name) _INTVARDEF (name, name##_internal)
# if defined HAVE_VISIBILITY_ATTRIBUTE
# define _INTVARDEF(name, aliasname) \
extern __typeof (name) aliasname __attribute__ ((alias (#name), \
@@ -337,65 +340,61 @@
# define INTVARDEF2(name, newname)
#endif
+
/* The following macros are used for PLT bypassing within libc.so
(and if needed other libraries similarly).
- First of all, you need to have the function prototyped somewhere,
- say in foo/foo.h:
-
- int foo (int __bar);
If calls to foo within libc.so should always go to foo defined in libc.so,
then in include/foo.h you add:
- libc_hidden_proto (foo)
+ int foo(int __bar);
+ libc_hidden_proto(foo)
line and after the foo function definition:
- int foo (int __bar)
- {
+ int foo(int __bar) {
return __bar;
}
- libc_hidden_def (foo)
+ libc_hidden_def(foo)
or
- int foo (int __bar)
- {
+ int foo(int __bar) {
return __bar;
}
- libc_hidden_weak (foo)
+ libc_hidden_weak(foo)
- Similarly for global data. If references to foo within libc.so should
- always go to foo defined in libc.so, then in include/foo.h you add:
+ Similarly for global data: if references to foo within libc.so
+ should always go to foo defined in libc.so, then in include/foo.h:
- libc_hidden_proto (foo)
+ extern int foo;
+ libc_hidden_proto(foo)
- line and after foo's definition:
+ and after foo's definition:
int foo = INITIAL_FOO_VALUE;
- libc_hidden_data_def (foo)
+ libc_hidden_data_def(foo)
or
int foo = INITIAL_FOO_VALUE;
- libc_hidden_data_weak (foo)
+ libc_hidden_data_weak(foo)
If foo is normally just an alias (strong or weak) to some other function,
you should use the normal strong_alias first, then add libc_hidden_def
or libc_hidden_weak:
- int baz (int __bar)
- {
+ int baz(int __bar) {
return __bar;
}
- strong_alias (baz, foo)
- libc_hidden_weak (foo)
+ strong_alias(baz, foo)
+ libc_hidden_weak(foo)
If the function should be internal to multiple objects, say ld.so and
libc.so, the best way is to use:
#if !defined NOT_IN_libc || defined IS_IN_rtld
- hidden_proto (foo)
+ hidden_proto(foo)
#endif
in include/foo.h and the normal macros at all function definitions
@@ -404,29 +403,47 @@
If versioned_symbol macro is used to define foo,
libc_hidden_ver macro should be used, as in:
- int __real_foo (int __bar)
- {
+ int __real_foo(int __bar) {
return __bar;
}
- versioned_symbol (libc, __real_foo, foo, GLIBC_2_1);
- libc_hidden_ver (__real_foo, foo) */
+ versioned_symbol(libc, __real_foo, foo, GLIBC_2_1);
+ libc_hidden_ver(__real_foo, foo)
+ */
/* uClibc specific (the above comment was copied from glibc):
- * a. when ppc64 will be supported, we need changes to support:
+ *
+ * when ppc64 will be supported, we need changes to support
* strong_data_alias (used by asm hidden_data_def)
- * b. libc_hidden_proto(foo) should be added after the header having foo's prototype
- * or after extern foo... to all source files that should use the internal version
- * of foo within libc, even to the file defining foo itself, libc_hidden_def does
- * not hide __GI_foo itself, although the name suggests it (hiding is done exclusively
- * by libc_hidden_proto). The reasoning to have it after the header w/ foo's prototype is
- * to get first the __REDIRECT from original header and then create the __GI_foo alias
- * c. no versioning support, hidden[_data]_ver are noop
- * d. hidden_def() in asm is _hidden_strong_alias (not strong_alias) */
-
-/* Arrange to hide uClibc internals */
-#if (defined __GNUC__ && \
- (defined __GNUC_MINOR__ && ( __GNUC__ >= 3 && __GNUC_MINOR__ >= 3 ) \
- || __GNUC__ >= 4)) || defined __ICC
+ *
+ * no versioning support, hidden[_data]_ver are noop
+ *
+ * hidden_def() in asm is _hidden_strong_alias (not strong_alias)
+ *
+ * libc_hidden_proto(foo) should be added after declaration
+ * in the header, or after extern foo... in all source files
+ * (this is discouraged).
+ * libc_hidden_def does not hide __GI_foo itself, although the name
+ * suggests it (hiding is done exclusively by libc_hidden_proto).
+
+FIXME! - ?
+ * The reasoning to have it after the header w/ foo's prototype is
+ * to get first the __REDIRECT from original header and then create
+ * the __GI_foo alias
+
+ * Hunt for references which still go through PLT (example for x86):
+ * build shared lib, then disassemble it and search for <xxx@plt>:
+ * $ objdump -drx libuClibc-*.so >disasm.txt
+ * $ grep -F '@plt>:' disasm.txt
+ *
+ * In uclibc, malloc/free and related functions should be called
+ * through PLT (making it possible to use alternative malloc),
+ * and possibly some __pthread_xxx functions can be called through PLT
+ * (why?). The rest should not use PLT.
+ */
+
+#if (defined __GNUC__ && defined __GNUC_MINOR__ \
+ && (( __GNUC__ >= 3 && __GNUC_MINOR__ >= 3) || __GNUC__ >= 4) \
+ ) || defined __ICC
# define attribute_hidden __attribute__ ((visibility ("hidden")))
# define __hidden_proto_hiddenattr(attrs...) __attribute__ ((visibility ("hidden"), ##attrs))
#else
@@ -435,67 +452,69 @@
#endif
#if /*!defined STATIC &&*/ !defined __BCC__
+
# ifndef __ASSEMBLER__
# define hidden_proto(name, attrs...) __hidden_proto (name, __GI_##name, ##attrs)
# define __hidden_proto(name, internal, attrs...) \
- extern __typeof (name) name __asm__ (__hidden_asmname (#internal)) \
- __hidden_proto_hiddenattr (attrs);
+ extern __typeof (name) name __asm__ (__hidden_asmname (#internal)) \
+ __hidden_proto_hiddenattr (attrs);
# define __hidden_asmname(name) __hidden_asmname1 (__USER_LABEL_PREFIX__, name)
# define __hidden_asmname1(prefix, name) __hidden_asmname2(prefix, name)
# define __hidden_asmname2(prefix, name) #prefix name
# define __hidden_ver1(local, internal, name) \
- extern __typeof (name) __EI_##name __asm__(__hidden_asmname (#internal)); \
- extern __typeof (name) __EI_##name __attribute__((alias (__hidden_asmname1 (,#local))))
+ extern __typeof (name) __EI_##name __asm__(__hidden_asmname (#internal)); \
+ extern __typeof (name) __EI_##name __attribute__((alias (__hidden_asmname1 (,#local))))
# define hidden_ver(local, name) __hidden_ver1(local, __GI_##name, name);
# define hidden_data_ver(local, name) hidden_ver(local, name)
# define hidden_def(name) __hidden_ver1(__GI_##name, name, name);
# define hidden_data_def(name) hidden_def(name)
-# define hidden_weak(name) \
+# define hidden_weak(name) \
__hidden_ver1(__GI_##name, name, name) __attribute__((weak));
# define hidden_data_weak(name) hidden_weak(name)
# else /* __ASSEMBLER__ */
-# ifdef HAVE_ASM_SET_DIRECTIVE
-# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define _hidden_strong_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- .hidden C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original) ASM_LINE_SEP \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP \
- .hidden C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP \
- .set C_SYMBOL_DOT_NAME (alias),C_SYMBOL_DOT_NAME (original)
-# else
-# define _hidden_strong_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- .hidden C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
-# endif
-# else
-# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define _hidden_strong_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- .hidden C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP \
- .hidden C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
-# else
-# define _hidden_strong_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- .hidden C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
+
+# ifdef HAVE_ASM_SET_DIRECTIVE
+# ifdef HAVE_ASM_GLOBAL_DOT_NAME
+# define _hidden_strong_alias(original, alias) \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ .hidden C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ .set C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original) ASM_LINE_SEP \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \
+ .hidden C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \
+ .set C_SYMBOL_DOT_NAME(alias),C_SYMBOL_DOT_NAME(original)
+# else
+# define _hidden_strong_alias(original, alias) \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ .hidden C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ .set C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original)
+# endif
+# else /* dont have .set directive */
+# ifdef HAVE_ASM_GLOBAL_DOT_NAME
+# define _hidden_strong_alias(original, alias) \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ .hidden C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ C_SYMBOL_NAME(alias) = C_SYMBOL_NAME(original) ASM_LINE_SEP \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \
+ .hidden C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \
+ C_SYMBOL_DOT_NAME(alias) = C_SYMBOL_DOT_NAME(original)
+# else
+# define _hidden_strong_alias(original, alias) \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ .hidden C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ C_SYMBOL_NAME(alias) = C_SYMBOL_NAME(original)
+# endif
# endif
-# endif
# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define _hidden_weak_alias(original, alias) \
- .hidden C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- .hidden C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP \
- weak_alias(original, alias)
+# define _hidden_weak_alias(original, alias) \
+ .hidden C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ .hidden C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \
+ weak_alias(original, alias)
# else
-# define _hidden_weak_alias(original, alias) \
- .hidden C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- weak_alias(original, alias)
+# define _hidden_weak_alias(original, alias) \
+ .hidden C_SYMBOL_NAME(alias) ASM_LINE_SEP \
+ weak_alias(original, alias)
# endif
/* For assembly, we need to do the opposite of what we do in C:
@@ -519,19 +538,23 @@
# define HIDDEN_JUMPTARGET(name) __GI_##name
# endif
# endif /* __ASSEMBLER__ */
-#else /* SHARED */
+
+#else /* not SHARED */
+
# ifndef __ASSEMBLER__
# define hidden_proto(name, attrs...)
# else
# define HIDDEN_JUMPTARGET(name) name
-# endif /* Not __ASSEMBLER__ */
+# endif /* not __ASSEMBLER__ */
# define hidden_weak(name)
# define hidden_def(name)
# define hidden_ver(local, name)
# define hidden_data_weak(name)
# define hidden_data_def(name)
# define hidden_data_ver(local, name)
-#endif /* SHARED */
+
+#endif /* SHARED / not SHARED */
+
/* uClibc does not support versioning yet. */
#define versioned_symbol(lib, local, symbol, version) /* weak_alias(local, symbol) */