Use clang's nullability instead of nonnull.
http://clang.llvm.org/docs/AttributeReference.html#nonnull
_Nonnull is similar to the nonnull attribute in that it will instruct
compilers to warn the user if it can prove that a null argument is
being passed. Unlike the nonnull attribute, this annotation indicated
that a value *should not* be null, not that it *cannot* be null, or
even that the behavior is undefined. The important distinction is that
the optimizer will perform surprising optimizations like the
following:
void foo(void*) __attribute__(nonnull, 1);
int bar(int* p) {
foo(p);
// The following null check will be elided because nonnull
// attribute means that, since we call foo with p, p can be
// assumed to not be null. Thus this will crash if we are called
// with a null pointer.
if (src != NULL) {
return *p;
}
return 0;
}
int main() {
return bar(NULL);
}
Note that by doing this we are no longer attaching any sort of
attribute for GCC (GCC doesn't support attaching nonnull directly to a
parameter, only to the function and naming the arguments
positionally). This means we won't be getting a warning for this case
from GCC any more. People that listen to warnings tend to use clang
anyway, and we're quickly moving toward that as the default, so this
seems to be an acceptable tradeoff.
Change-Id: Ie05fe7cec2f19a082c1defb303f82bcf9241b88d
diff --git a/libc/bionic/pthread_mutex.cpp b/libc/bionic/pthread_mutex.cpp
index 7d8e8a8..14e0ab0 100644
--- a/libc/bionic/pthread_mutex.cpp
+++ b/libc/bionic/pthread_mutex.cpp
@@ -502,6 +502,9 @@
int pthread_mutex_lock(pthread_mutex_t* mutex_interface) {
#if !defined(__LP64__)
+ // Some apps depend on being able to pass NULL as a mutex and get EINVAL
+ // back. Don't need to worry about it for LP64 since the ABI is brand new,
+ // but keep compatibility for LP32. http://b/19995172.
if (mutex_interface == NULL) {
return EINVAL;
}
@@ -523,6 +526,9 @@
int pthread_mutex_unlock(pthread_mutex_t* mutex_interface) {
#if !defined(__LP64__)
+ // Some apps depend on being able to pass NULL as a mutex and get EINVAL
+ // back. Don't need to worry about it for LP64 since the ABI is brand new,
+ // but keep compatibility for LP32. http://b/19995172.
if (mutex_interface == NULL) {
return EINVAL;
}