From d466780c7cedb41edcf13f28ad900556c6aaa5b2 Mon Sep 17 00:00:00 2001
From: David 'Digit' Turner <digit@google.com>
Date: Fri, 11 Jun 2010 13:18:41 -0700
Subject: Add missing SMP barriers to libstdc++

Change-Id: I20a8dcd2e3316ac60237e800c682cacc8e59e187
---
 libstdc++/Android.mk                    | 15 +++++++++++++++
 libstdc++/src/one_time_construction.cpp | 19 ++++++++++++-------
 2 files changed, 27 insertions(+), 7 deletions(-)

(limited to 'libstdc++')

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_SRC_FILES:= \
 
 LOCAL_MODULE:= libstdc++
 
+LOCAL_CFLAGS := $(libstdc++_cflags)
+
 LOCAL_SYSTEM_SHARED_LIBRARIES := libc
 
 include $(BUILD_SHARED_LIBRARY)
@@ -21,6 +34,8 @@ LOCAL_SRC_FILES:= \
 	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 @@ extern "C" int __cxa_guard_acquire(int volatile * gv)
     // 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 @@ extern "C" void __cxa_guard_release(int volatile * gv)
 {
     // 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_release(int volatile * gv)
 
 extern "C" void __cxa_guard_abort(int volatile * gv)
 {
+    ANDROID_MEMBAR_FULL();
     *gv = 0;
     __futex_wake(gv, 0x7fffffff);
 }
-- 
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