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am d466780c: Add missing SMP barriers to libstdc++

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Merge commit 'd466780c7cedb41edcf13f28ad900556c6aaa5b2' into gingerbread-plus-aosp

* commit 'd466780c7cedb41edcf13f28ad900556c6aaa5b2':
  Add missing SMP barriers to libstdc++
This commit is contained in:
David 'Digit' Turner 2010-07-07 14:20:35 -07:00 committed by Android Git Automerger
commit 973a83f04d
2 changed files with 27 additions and 7 deletions
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15
libstdc++/Android.mk
View File

@ -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

19
libstdc++/src/one_time_construction.cpp
View File

@ -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);
}