Cherry-pick a upstream patch for a data loading bug

patches/dataload.patch

Index: patches/dataload.patch
diff --git a/patches/dataload.patch b/patches/dataload.patch
new file mode 100644
index 0000000000000000000000000000000000000000..f246f157938ed37dd8381f3b7df346e52a977e55
--- /dev/null
+++ b/patches/dataload.patch
@@ -0,0 +1,152 @@
+diff --git a/source/common/udata.cpp b/source/common/udata.cpp
+index e6d8a35..80bea06 100644
+--- a/source/common/udata.cpp
++++ b/source/common/udata.cpp
+@@ -1,7 +1,7 @@
+ /*
+ ******************************************************************************
+ *
+-*   Copyright (C) 1999-2014, International Business Machines
++*   Copyright (C) 1999-2015, International Business Machines
+ *   Corporation and others.  All Rights Reserved.
+ *
+ ******************************************************************************
+@@ -29,6 +29,7 @@ might have to #include some other header
+ #include "charstr.h"
+ #include "cmemory.h"
+ #include "cstring.h"
++#include "mutex.h"
+ #include "putilimp.h"
+ #include "uassert.h"
+ #include "ucln_cmn.h"
+@@ -100,14 +101,15 @@ static UDataMemory *udata_findCachedData(const char *path);
+  * that they really need, reducing the size of binaries that take advantage
+  * of this.
+  */
+-static UDataMemory *gCommonICUDataArray[10] = { NULL };
++static UDataMemory *gCommonICUDataArray[10] = { NULL };   // Access protected by icu global mutex.
+ 
+-static UBool gHaveTriedToLoadCommonData = FALSE;  /* See extendICUData(). */
++static u_atomic_int32_t gHaveTriedToLoadCommonData = ATOMIC_INT32_T_INITIALIZER(0);  //  See extendICUData().
+ 
+ static UHashtable  *gCommonDataCache = NULL;  /* Global hash table of opened ICU data files.  */
+ static icu::UInitOnce gCommonDataCacheInitOnce = U_INITONCE_INITIALIZER;
+ 
+-static UDataFileAccess  gDataFileAccess = UDATA_DEFAULT_ACCESS;
++static UDataFileAccess  gDataFileAccess = UDATA_DEFAULT_ACCESS;  // Access not synchronized.
++                                                                 // Modifying is documented as thread-unsafe.
+ 
+ static UBool U_CALLCONV
+ udata_cleanup(void)
+@@ -124,7 +126,7 @@ udata_cleanup(void)
+         udata_close(gCommonICUDataArray[i]);
+         gCommonICUDataArray[i] = NULL;
+     }
+-    gHaveTriedToLoadCommonData = FALSE;
++    gHaveTriedToLoadCommonData = 0;
+ 
+     return TRUE;                   /* Everything was cleaned up */
+ }
+@@ -139,14 +141,16 @@ findCommonICUDataByName(const char *inBasename)
+     if (pData == NULL)
+         return FALSE;
+ 
+-    for (i = 0; i < UPRV_LENGTHOF(gCommonICUDataArray); ++i) {
+-        if ((gCommonICUDataArray[i] != NULL) && (gCommonICUDataArray[i]->pHeader == pData->pHeader)) {
+-            /* The data pointer is already in the array. */
+-            found = TRUE;
+-            break;
++    {
++        Mutex lock;
++        for (i = 0; i < UPRV_LENGTHOF(gCommonICUDataArray); ++i) {
++            if ((gCommonICUDataArray[i] != NULL) && (gCommonICUDataArray[i]->pHeader == pData->pHeader)) {
++                /* The data pointer is already in the array. */
++                found = TRUE;
++                break;
++            }
+         }
+     }
+-
+     return found;
+ }
+ 
+@@ -663,7 +667,11 @@ openCommonData(const char *path,          /*  Path from OpenChoice?          */
+         if(commonDataIndex >= UPRV_LENGTHOF(gCommonICUDataArray)) {
+             return NULL;
+         }
+-        if(gCommonICUDataArray[commonDataIndex] == NULL) {
++        {
++            Mutex lock;
++            if(gCommonICUDataArray[commonDataIndex] != NULL) {
++                return gCommonICUDataArray[commonDataIndex];
++            }
+             int32_t i;
+             for(i = 0; i < commonDataIndex; ++i) {
+                 if(gCommonICUDataArray[i]->pHeader == &U_ICUDATA_ENTRY_POINT.hdr) {
+@@ -671,23 +679,26 @@ openCommonData(const char *path,          /*  Path from OpenChoice?          */
+                     return NULL;
+                 }
+             }
++        }
+ 
+-            /* Add the linked-in data to the list. */
+-            /*
+-             * This is where we would check and call weakly linked partial-data-library
+-             * access functions.
+-             */
+-            /*
+-            if (uprv_getICUData_collation) {
+-                setCommonICUDataPointer(uprv_getICUData_collation(), FALSE, pErrorCode);
+-            }
+-            if (uprv_getICUData_conversion) {
+-                setCommonICUDataPointer(uprv_getICUData_conversion(), FALSE, pErrorCode);
+-            }
+-            */
+-            setCommonICUDataPointer(&U_ICUDATA_ENTRY_POINT.hdr, FALSE, pErrorCode);
++        /* Add the linked-in data to the list. */
++        /*
++         * This is where we would check and call weakly linked partial-data-library
++         * access functions.
++         */
++        /*
++        if (uprv_getICUData_collation) {
++            setCommonICUDataPointer(uprv_getICUData_collation(), FALSE, pErrorCode);
++        }
++        if (uprv_getICUData_conversion) {
++            setCommonICUDataPointer(uprv_getICUData_conversion(), FALSE, pErrorCode);
++        }
++        */
++        setCommonICUDataPointer(&U_ICUDATA_ENTRY_POINT.hdr, FALSE, pErrorCode);
++        {
++            Mutex lock;
++            return gCommonICUDataArray[commonDataIndex];
+         }
+-        return gCommonICUDataArray[commonDataIndex];
+     }
+ 
+ 
+@@ -795,7 +806,7 @@ static UBool extendICUData(UErrorCode *pErr)
+     static UMutex extendICUDataMutex = U_MUTEX_INITIALIZER;
+     umtx_lock(&extendICUDataMutex);
+ #endif
+-    if(!gHaveTriedToLoadCommonData) {
++    if(!umtx_loadAcquire(gHaveTriedToLoadCommonData)) {
+         /* See if we can explicitly open a .dat file for the ICUData. */
+         pData = openCommonData(
+                    U_ICUDATA_NAME,            /*  "icudt20l" , for example.          */
+@@ -820,7 +831,7 @@ static UBool extendICUData(UErrorCode *pErr)
+                        pErr);             /*  setCommonICUData honors errors; NOP if error set    */
+         }
+ 
+-        gHaveTriedToLoadCommonData = TRUE;
++        umtx_storeRelease(gHaveTriedToLoadCommonData, 1);
+     }
+ 
+     didUpdate = findCommonICUDataByName(U_ICUDATA_NAME);  /* Return 'true' when a racing writes out the extended                        */
+@@ -1398,5 +1409,6 @@ udata_getInfo(UDataMemory *pData, UDataInfo *pInfo) {
+ 
+ U_CAPI void U_EXPORT2 udata_setFileAccess(UDataFileAccess access, UErrorCode * /*status*/)
+ {
++    // Note: this function is documented as not thread safe.
+     gDataFileAccess = access;
+ }