This patch defines a few new macros that can be used to control the
visibility of symbols exported by the C library:
- ENTRY_PRIVATE() can be used in assembly sources to indicate
that an assembler function should have "hidden" visibility, i.e.
will never be exported by the C library's shared library.
This is the equivalent of using __LIBC_HIDDEN__ for a C function,
but ENTRY_PRIVATE() works like ENTRY(), and must be used with
END() to tag the end of the function.
- __LIBC_ABI_PUBLIC__ can be used to tag a C functions as being
part of the C library's public ABI. This is important for a
few functions that must be exposed by the NDK to maintain
binary compatibility.
Once a symbol has been tagged with this macro, it shall
*never* be removed from the library, even if it becomes
directly unused due to implementation changes
(e.g. __is_threaded).
- __LIBC_ABI_PRIVATE__ can be used for C functions that should
always be exported by the C library because they are used by
other libraries in the platform, but should not be exposed
by the NDK. It is possible to remove such symbols from the
implementation if all callers are also modified.
+ Add missing END() assembly macro for x86
Change-Id: Ia96236ea0dbec41d57bea634b39d246b30e5e234
__atomic_cmpxchg and other related atomic operations did not
provide memory barriers, which can be a problem for non-platform
code that links against them when it runs on multi-core devices.
This patch does two things to fix this:
- It modifies the existing implementation of the functions
that are exported by the C library to always provide
full memory barriers. We need to keep them exported by
the C library to prevent breaking existing application
machine code.
- It also modifies <sys/atomics.h> to only export
always-inlined versions of the functions, to ensure that
any application code compiled against the new header will
not rely on the platform version of the functions.
This ensure that said machine code will run properly on
all multi-core devices.
This is based on the GCC built-in sync primitives.
The end result should be only slightly slower than the
previous implementation.
Note that the platform code does not use these functions
at all. A previous patch completely removed their usage in
the pthread and libstdc++ code.
+ rename arch-arm/bionic/atomics_arm.S to futex_arm.S
+ rename arch-x86/bionic/atomics_x86.S to futex_x86.S
+ remove arch-x86/include/sys/atomics.h which already
provided inlined functions to the x86 platform.
Change-Id: I752a594475090cf37fa926bb38209c2175dda539
This patch changes the declaration of size_t on x86 targets
to test for the __ANDROID__ macro, instead of ANDROID
__ANDROID__ should be a builting toolchain macro, while ANDROID
is usually added manually during the build.
Testing against __ANDROID__ allows us to use the header when
using the NDK's standalone x86 toolchain.
This is related to http://code.google.com/p/android/issues/detail?id=19011
The bug was already fixed in the NDK platform headers, this simply updates
the C library one accordingly.
Change-Id: Ie038c4c8b37b7d24e2e4ae4d7a63371b69c9a51e
