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authorWaldemar Brodkorb <wbx@openadk.org>2016-12-07 07:56:44 +0100
committerWaldemar Brodkorb <wbx@openadk.org>2016-12-10 15:14:33 +0100
commit5ca03df6978345c297225212cc0ca33d476b0272 (patch)
tree873ea7e2b6d2202dd01bf27be9d5b3b5ab24c7a2 /libc
parent6579597083e608f5a66fe8a898d113c2588e2c8f (diff)
threads: optimize single threaded applications
Revert the removal of the weak pthread functions and guarantee a link order so that single threaded applications doesn't link in all the pthread functions they don't use. Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Tested-by: Waldemar Brodkorb <wbx@uclibc-ng.org>
Diffstat (limited to 'libc')
-rw-r--r--libc/misc/internals/Makefile.in4
-rw-r--r--libc/misc/internals/__uClibc_main.c37
2 files changed, 40 insertions, 1 deletions
diff --git a/libc/misc/internals/Makefile.in b/libc/misc/internals/Makefile.in
index ae094ee23..ce7f75af5 100644
--- a/libc/misc/internals/Makefile.in
+++ b/libc/misc/internals/Makefile.in
@@ -25,7 +25,9 @@ libc-shared-y += $(MISC_INTERNALS_OUT)/__uClibc_main.oS
else
libc-shared-y += $(MISC_INTERNALS_OUT)/__uClibc_main.os
endif
-libc-static-y += $(MISC_INTERNALS_OUT)/__uClibc_main.o
+# link order is important to not pull in pthread functions, when
+# a single threaded application is statically linked
+libc-static-y := $(MISC_INTERNALS_OUT)/__uClibc_main.o $(libc-static-y)
libc-static-$(UCLIBC_FORMAT_FLAT_SEP_DATA) += \
$(MISC_INTERNALS_OUT)/shared_flat_initfini.o \
$(MISC_INTERNALS_OUT)/shared_flat_add_library.o
diff --git a/libc/misc/internals/__uClibc_main.c b/libc/misc/internals/__uClibc_main.c
index 46e24d891..d80565e2c 100644
--- a/libc/misc/internals/__uClibc_main.c
+++ b/libc/misc/internals/__uClibc_main.c
@@ -68,6 +68,43 @@ uintptr_t __stack_chk_guard attribute_relro;
void internal_function _dl_aux_init (ElfW(auxv_t) *av);
+#ifdef __UCLIBC_HAS_THREADS__
+/*
+ * uClibc internal locking requires that we have weak aliases
+ * for dummy functions in case a single threaded application is linked.
+ * This needs to be in compilation unit that is pulled always
+ * in or linker will disregard these weaks.
+ */
+
+static int __pthread_return_0 (pthread_mutex_t *unused) { return 0; }
+weak_alias (__pthread_return_0, __pthread_mutex_lock)
+weak_alias (__pthread_return_0, __pthread_mutex_trylock)
+weak_alias (__pthread_return_0, __pthread_mutex_unlock)
+
+int weak_function
+__pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *attr)
+{
+ return 0;
+}
+
+void weak_function
+_pthread_cleanup_push_defer(struct _pthread_cleanup_buffer *__buffer,
+ void (*__routine) (void *), void *__arg)
+{
+ __buffer->__routine = __routine;
+ __buffer->__arg = __arg;
+}
+
+void weak_function
+_pthread_cleanup_pop_restore(struct _pthread_cleanup_buffer *__buffer,
+ int __execute)
+{
+ if (__execute)
+ __buffer->__routine(__buffer->__arg);
+}
+
+#endif /* __UCLIBC_HAS_THREADS__ */
+
#endif /* !SHARED */
/* Defeat compiler optimization which assumes function addresses are never NULL */