Add missing SMP barriers to libstdc++
Change-Id: I20a8dcd2e3316ac60237e800c682cacc8e59e187
diff --git a/libstdc++/Android.mk b/libstdc++/Android.mk
index df97c9f..8bc181f 100644
--- a/libstdc++/Android.mk
+++ b/libstdc++/Android.mk
@@ -1,4 +1,15 @@
LOCAL_PATH:= $(call my-dir)
+
+# Common C++ flags to build this library.
+# Note that we need to access private Bionic headers
+# and define ANDROID_SMP accordingly.
+libstdc++_cflags := -Ibionic/libc/private
+ifeq ($(TARGET_CPU_SMP),true)
+ libstdc++_cflags += -DANDROID_SMP=1
+else
+ libstdc++_cflags += -DANDROID_SMP=0
+endif
+
include $(CLEAR_VARS)
LOCAL_SRC_FILES:= \
@@ -9,6 +20,8 @@
LOCAL_MODULE:= libstdc++
+LOCAL_CFLAGS := $(libstdc++_cflags)
+
LOCAL_SYSTEM_SHARED_LIBRARIES := libc
include $(BUILD_SHARED_LIBRARY)
@@ -21,6 +34,8 @@
src/pure_virtual.cpp \
src/typeinfo.cpp
+LOCAL_CFLAGS := $(libstdc++_cflags)
+
LOCAL_MODULE:= libstdc++
LOCAL_SYSTEM_SHARED_LIBRARIES := libc
diff --git a/libstdc++/src/one_time_construction.cpp b/libstdc++/src/one_time_construction.cpp
index 304afb8..2a44c79 100644
--- a/libstdc++/src/one_time_construction.cpp
+++ b/libstdc++/src/one_time_construction.cpp
@@ -10,10 +10,8 @@
#include <stddef.h>
#include <sys/atomics.h>
-
-extern "C" int __futex_wait(volatile void *ftx, int val, const struct timespec *timeout);
-extern "C" int __futex_wake(volatile void *ftx, int count);
-
+#include <bionic_futex.h>
+#include <bionic_atomic_inline.h>
extern "C" int __cxa_guard_acquire(int volatile * gv)
{
@@ -22,13 +20,17 @@
// 6 untouched, wait and return 0
// 1 untouched, return 0
retry:
- if (__atomic_cmpxchg(0, 0x2, gv) == 0)
+ if (__atomic_cmpxchg(0, 0x2, gv) == 0) {
+ ANDROID_MEMBAR_FULL();
return 1;
-
+ }
__atomic_cmpxchg(0x2, 0x6, gv); // Indicate there is a waiter
__futex_wait(gv, 0x6, NULL);
+
if(*gv != 1) // __cxa_guard_abort was called, let every thread try since there is no return code for this condition
goto retry;
+
+ ANDROID_MEMBAR_FULL();
return 0;
}
@@ -36,8 +38,10 @@
{
// 2 -> 1
// 6 -> 1, and wake
- if (__atomic_cmpxchg(0x2, 0x1, gv) == 0)
+ ANDROID_MEMBAR_FULL();
+ if (__atomic_cmpxchg(0x2, 0x1, gv) == 0) {
return;
+ }
*gv = 0x1;
__futex_wake(gv, 0x7fffffff);
@@ -45,6 +49,7 @@
extern "C" void __cxa_guard_abort(int volatile * gv)
{
+ ANDROID_MEMBAR_FULL();
*gv = 0;
__futex_wake(gv, 0x7fffffff);
}