Remove dependency of System.Globalization.Native.so on specific ICU version (#7773)

Remove dependency of System.Globalization.Native.so on specific ICU version

15 files changed, 499 insertions, 33 deletions

diff --git a/src/corefx/System.Globalization.Native/CMakeLists.txt b/src/corefx/System.Globalization.Native/CMakeLists.txt
index 3d9e392132..5892856dfe 100644
--- a/src/corefx/System.Globalization.Native/CMakeLists.txt
+++ b/src/corefx/System.Globalization.Native/CMakeLists.txt
@@ -14,7 +14,7 @@ if(UTYPES_H STREQUAL UTYPES_H-NOTFOUND)
     return()
 endif()
 
-if(NOT CLR_CMAKE_PLATFORM_DARWIN)
+if (FEATURE_FIXED_ICU_VERSION AND NOT CLR_CMAKE_PLATFORM_DARWIN)
     find_library(ICUUC icuuc)
     if(ICUUC STREQUAL ICUUC-NOTFOUND)
         message(FATAL_ERROR "Cannot find libicuuc, try installing libicu-dev (or the appropriate package for your platform)")
@@ -26,12 +26,16 @@ if(NOT CLR_CMAKE_PLATFORM_DARWIN)
         message(FATAL_ERROR "Cannot find libicui18n, try installing libicu-dev (or the appropriate package for your platform)")
         return()
     endif()
-else()
+endif()
+
+if(CLR_CMAKE_PLATFORM_DARWIN)
     find_library(ICUCORE icucore)
     if(ICUI18N STREQUAL ICUCORE-NOTFOUND)
         message(FATAL_ERROR "Cannot find libicucore, skipping build for System.Globalization.Native. .NET globalization is not expected to function.")
         return()
     endif()
+    # On Darwin, we always use the OS provided ICU
+    SET(FEATURE_FIXED_ICU_VERSION 1)
 endif()
 
 include(configure.cmake)
@@ -50,6 +54,12 @@ set(NATIVEGLOBALIZATION_SOURCES
     timeZoneInfo.cpp
 )
 
+if (NOT FEATURE_FIXED_ICU_VERSION)
+    list(APPEND NATIVEGLOBALIZATION_SOURCES
+        icushim.cpp
+    )
+endif()
+
 include_directories(${UTYPES_H})
 
 _add_library(System.Globalization.Native
@@ -60,11 +70,21 @@ _add_library(System.Globalization.Native
 # Disable the "lib" prefix.
 set_target_properties(System.Globalization.Native PROPERTIES PREFIX "")
 
+if (FEATURE_FIXED_ICU_VERSION)
+    add_definitions(-DFEATURE_FIXED_ICU_VERSION)
+endif()
+
 if(NOT CLR_CMAKE_PLATFORM_DARWIN)
-    target_link_libraries(System.Globalization.Native
-        ${ICUUC}
-        ${ICUI18N}
-    )
+    if (FEATURE_FIXED_ICU_VERSION)
+        target_link_libraries(System.Globalization.Native
+            ${ICUUC}
+            ${ICUI18N}
+        )
+    elseif(NOT CMAKE_SYSTEM_NAME STREQUAL FreeBSD AND NOT CMAKE_SYSTEM_NAME STREQUAL NetBSD)
+        target_link_libraries(System.Globalization.Native
+            dl
+        )
+    endif()
 else()
     target_link_libraries(System.Globalization.Native
         ${ICUCORE}
@@ -74,4 +94,4 @@ else()
 endif()
 
 # add the install targets
-install_clr(System.Globalization.Native)
\ No newline at end of file
+install_clr(System.Globalization.Native)
diff --git a/src/corefx/System.Globalization.Native/calendarData.cpp b/src/corefx/System.Globalization.Native/calendarData.cpp
index f91cc0cb57..49436078d8 100644
--- a/src/corefx/System.Globalization.Native/calendarData.cpp
+++ b/src/corefx/System.Globalization.Native/calendarData.cpp
@@ -6,7 +6,7 @@
 #include <string.h>
 #include <vector>
 
-#include "config.h"
+#include "icushim.h"
 #include "locale.hpp"
 #include "holders.h"
 #include "errors.h"
diff --git a/src/corefx/System.Globalization.Native/casing.cpp b/src/corefx/System.Globalization.Native/casing.cpp
index 58b47fc810..918b8fe6ed 100644
--- a/src/corefx/System.Globalization.Native/casing.cpp
+++ b/src/corefx/System.Globalization.Native/casing.cpp
@@ -5,8 +5,7 @@
 
 #include <assert.h>
 #include <stdint.h>
-#include <unicode/uchar.h>
-#include <unicode/utf16.h>
+#include "icushim.h"
 
 /*
 Function:
diff --git a/src/corefx/System.Globalization.Native/collation.cpp b/src/corefx/System.Globalization.Native/collation.cpp
index 42a9674632..4a6fafdbd6 100644
--- a/src/corefx/System.Globalization.Native/collation.cpp
+++ b/src/corefx/System.Globalization.Native/collation.cpp
@@ -8,12 +8,8 @@
 #include <stdint.h>
 #include <vector>
 #include <map>
-#include <unicode/uchar.h>
-#include <unicode/ucol.h>
-#include <unicode/usearch.h>
-#include <unicode/utf16.h>
 
-#include "config.h"
+#include "icushim.h"
 
 const int32_t CompareOptionsIgnoreCase = 0x1;
 const int32_t CompareOptionsIgnoreNonSpace = 0x2;
diff --git a/src/corefx/System.Globalization.Native/errors.h b/src/corefx/System.Globalization.Native/errors.h
index 2bfbdb2ba1..031ea7b120 100644
--- a/src/corefx/System.Globalization.Native/errors.h
+++ b/src/corefx/System.Globalization.Native/errors.h
@@ -4,8 +4,6 @@
 
 #pragma once
 
-#include <unicode/utypes.h>
-
 /*
 * These values should be kept in sync with
 * Interop.GlobalizationInterop.ResultCode
diff --git a/src/corefx/System.Globalization.Native/holders.h b/src/corefx/System.Globalization.Native/holders.h
index 529451f77c..83e253d297 100644
--- a/src/corefx/System.Globalization.Native/holders.h
+++ b/src/corefx/System.Globalization.Native/holders.h
@@ -2,14 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#include <unicode/ucal.h>
-#include <unicode/uenum.h>
-#include <unicode/udatpg.h>
-#include <unicode/udat.h>
-#include <unicode/unum.h>
-#include <unicode/uldnames.h>
-#include <unicode/ures.h>
-
 // IcuHolder is a template that can manage the lifetime of a raw pointer to ensure that it is cleaned up at the correct
 // time.  The general usage pattern is to aquire some ICU resource via an _open call, then construct a holder using the
 // pointer and UErrorCode to manage the lifetime.  When the holder goes out of scope, the coresponding close method is
diff --git a/src/corefx/System.Globalization.Native/icushim.cpp b/src/corefx/System.Globalization.Native/icushim.cpp
new file mode 100644
index 0000000000..63f111b8b1
--- /dev/null
+++ b/src/corefx/System.Globalization.Native/icushim.cpp
@@ -0,0 +1,226 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+//
+
+#include <dlfcn.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+#include "icushim.h"
+
+// Define pointers to all the used ICU functions
+#define PER_FUNCTION_BLOCK(fn, lib) decltype(fn)* fn##_ptr;
+FOR_ALL_ICU_FUNCTIONS
+#undef PER_FUNCTION_BLOCK
+
+static void* libicuuc = nullptr;
+static void* libicui18n = nullptr;
+
+// Version ranges to search for each of the three version components
+// The rationale for major version range is that we support versions higher or
+// equal to the version we are built against and less or equal to that version
+// plus 20 to give us enough headspace. The ICU seems to version about twice
+// a year.
+static const int MinICUVersion = U_ICU_VERSION_MAJOR_NUM;
+static const int MaxICUVersion = MinICUVersion + 20;
+static const int MinMinorICUVersion = 1;
+static const int MaxMinorICUVersion = 5;
+static const int MinSubICUVersion = 1;
+static const int MaxSubICUVersion = 5;
+
+// .x.x.x, considering the max number of decimal digits for each component
+static const int MaxICUVersionStringLength = 33;
+
+// Get filename of an ICU library with the requested version in the name
+// There are three possible cases of the version components values:
+// 1. Only majorVer is not equal to -1 => result is baseFileName.majorver
+// 2. Only majorVer and minorVer are not equal to -1 => result is baseFileName.majorver.minorVer
+// 3. All components are not equal to -1 => result is baseFileName.majorver.minorVer.subver
+void GetVersionedLibFileName(const char* baseFileName, int majorVer, int minorVer, int subVer, char* result)
+{
+    assert(majorVer != -1);
+
+    int nameLen = sprintf(result, "%s.%d", baseFileName, majorVer);
+
+    if (minorVer != -1)
+    {
+        nameLen += sprintf(result + nameLen, ".%d", minorVer);
+        if (subVer != -1)
+        {
+            sprintf(result + nameLen, ".%d", subVer);
+        }    
+    }
+}
+
+// Try to open the necessary ICU libraries
+bool OpenICULibraries(int majorVer, int minorVer, int subVer)
+{
+    char libicuucName[64];
+    char libicui18nName[64];
+
+    static_assert(sizeof("libicuuc.so") + MaxICUVersionStringLength <= sizeof(libicuucName), "The libicuucName is too small");
+    GetVersionedLibFileName("libicuuc.so", majorVer, minorVer, subVer, libicuucName);
+
+    static_assert(sizeof("libicui18n.so") + MaxICUVersionStringLength <= sizeof(libicui18nName), "The libicui18nName is too small");
+    GetVersionedLibFileName("libicui18n.so", majorVer, minorVer, subVer, libicui18nName);
+
+    libicuuc = dlopen(libicuucName, RTLD_LAZY);
+    if (libicuuc != nullptr)
+    {
+        libicui18n = dlopen(libicui18nName, RTLD_LAZY);
+        if (libicui18n == nullptr)
+        {
+            dlclose(libicuuc);
+            libicuuc = nullptr;
+        }
+    }
+
+    return libicuuc != nullptr;
+}
+
+// Select libraries using the version override specified by the CLR_ICU_VERSION_OVERRIDE
+// environment variable.
+// The format of the string in this variable is majorVer[.minorVer[.subVer]] (the brackets
+// indicate optional parts).
+bool FindLibUsingOverride(int* majorVer, int* minorVer, int* subVer)
+{
+    char* versionOverride = getenv("CLR_ICU_VERSION_OVERRIDE");
+    if (versionOverride != nullptr)
+    {
+        int first = -1;
+        int second = -1;
+        int third = -1;
+
+        int matches = sscanf(versionOverride, "%d.%d.%d", &first, &second, &third);
+        if (matches > 0)
+        {
+            if (OpenICULibraries(first, second, third))
+            {
+                *majorVer = first;
+                *minorVer = second;
+                *subVer = third;
+                return true;
+            }
+        }
+    }
+
+    return false;
+}
+
+// Select the highest supported version of ICU present on the local machine
+// Search for library files with names including the major and minor version.
+bool FindLibWithMajorMinorVersion(int* majorVer, int* minorVer)
+{
+    for (int i = MaxICUVersion; i >= MinICUVersion; i--)
+    {
+        for (int j = MaxMinorICUVersion; j >= MinMinorICUVersion; j--)
+        {
+            if (OpenICULibraries(i, j, -1))
+            {
+                *majorVer = i;
+                *minorVer = j;
+                return true;
+            }
+        }
+    }
+
+    return false;
+}
+
+// Select the highest supported version of ICU present on the local machine
+// Search for library files with names including the major, minor and sub version.
+bool FindLibWithMajorMinorSubVersion(int* majorVer, int* minorVer, int* subVer)
+{
+    for (int i = MaxICUVersion; i >= MinICUVersion; i--)
+    {
+        for (int j = MaxMinorICUVersion; j >= MinMinorICUVersion; j--)
+        {
+            for (int k = MaxSubICUVersion; k >= MinSubICUVersion; k--)
+            {
+                if (OpenICULibraries(i, j, k))
+                {
+                    *majorVer = i;
+                    *minorVer = j;
+                    *subVer = k;
+                    return true;
+                }
+            }
+        }
+    }
+
+    return false;
+}
+
+// This function is ran at the end of dlopen for the current shared library
+__attribute__((constructor))
+void InitializeICUShim()
+{
+    int majorVer = -1;
+    int minorVer = -1;
+    int subVer = -1;
+
+    if (!FindLibUsingOverride(&majorVer, &minorVer, &subVer) &&
+        !FindLibWithMajorMinorVersion(&majorVer, &minorVer) &&
+        !FindLibWithMajorMinorSubVersion(&majorVer, &minorVer, &subVer))
+    {
+        // No usable ICU version found
+        fprintf(stderr, "No usable version of the ICU libraries was found\n");
+        abort();
+    }
+
+    char symbolName[128];
+    char symbolVersion[MaxICUVersionStringLength + 1] = "";
+
+    // Find out the format of the version string added to each symbol
+    // First try just the unversioned symbol
+    if (dlsym(libicuuc, "u_strlen") == nullptr)
+    {
+        // Now try just the _majorVer added
+        sprintf(symbolVersion, "_%d", majorVer);
+        sprintf(symbolName, "u_strlen%s", symbolVersion);
+        if (dlsym(libicuuc, symbolName) == nullptr)
+        {
+            // Now try the _majorVer_minorVer added
+            sprintf(symbolVersion, "_%d_%d", majorVer, minorVer);
+            sprintf(symbolName, "u_strlen%s", symbolVersion);
+            if (dlsym(libicuuc, symbolName) == nullptr)
+            {
+                // Finally, try the _majorVer_minorVer_subVer added
+                sprintf(symbolVersion, "_%d_%d_%d", majorVer, minorVer, subVer);
+                sprintf(symbolName, "u_strlen%s", symbolVersion);
+                if (dlsym(libicuuc, symbolName) == nullptr)
+                {
+                    fprintf(stderr, "ICU libraries use unknown symbol versioning\n");
+                    abort();
+                }
+            }
+        }
+    }
+
+    // Get pointers to all the ICU functions that are needed
+#define PER_FUNCTION_BLOCK(fn, lib) \
+    static_assert((sizeof(#fn) + MaxICUVersionStringLength + 1) <= sizeof(symbolName), "The symbolName is too small for symbol " #fn); \
+    sprintf(symbolName, #fn "%s", symbolVersion); \
+    fn##_ptr = (decltype(fn)*)dlsym(lib, symbolName); \
+    if (fn##_ptr == NULL) { fprintf(stderr, "Cannot get symbol %s from " #lib "\n", symbolName); abort(); }
+
+    FOR_ALL_ICU_FUNCTIONS
+#undef PER_FUNCTION_BLOCK
+}
+
+__attribute__((destructor))
+void ShutdownICUShim()
+{
+    if (libicuuc != nullptr)
+    {
+        dlclose(libicuuc);
+    }
+
+    if (libicui18n != nullptr)
+    {
+        dlclose(libicui18n);
+    }
+}
diff --git a/src/corefx/System.Globalization.Native/icushim.h b/src/corefx/System.Globalization.Native/icushim.h
new file mode 100644
index 0000000000..c9214c355f
--- /dev/null
+++ b/src/corefx/System.Globalization.Native/icushim.h
@@ -0,0 +1,237 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+//
+
+// Enable calling ICU functions through shims to enable support for 
+// multiple versions of ICU if the FEATURE_FIXED_ICU_VERSION is
+// not defined.
+
+#ifndef __ICUSHIM_H__
+#define __ICUSHIM_H__
+
+#include "config.h"
+
+#ifndef FEATURE_FIXED_ICU_VERSION
+#define U_DISABLE_RENAMING 1
+#endif
+
+// All ICU headers need to be included here so that all function prototypes are
+// available before the function pointers are declared below.
+#include <unicode/locid.h>
+#include <unicode/ucurr.h>
+#include <unicode/ucal.h>
+#include <unicode/uchar.h>
+#include <unicode/ucol.h>
+#include <unicode/udat.h>
+#include <unicode/udatpg.h>
+#include <unicode/uenum.h>
+#include <unicode/uidna.h>
+#include <unicode/uldnames.h>
+#include <unicode/ulocdata.h>
+#include <unicode/unorm2.h>
+#include <unicode/unum.h>
+#include <unicode/ures.h>
+#include <unicode/usearch.h>
+#include <unicode/utf16.h>
+#include <unicode/utypes.h>
+
+#ifndef FEATURE_FIXED_ICU_VERSION
+
+// List of all functions from the ICU libraries that are used in the System.Globalization.Native.so
+#define FOR_ALL_UNCONDITIONAL_ICU_FUNCTIONS \
+    PER_FUNCTION_BLOCK(u_charsToUChars, libicuuc) \
+    PER_FUNCTION_BLOCK(u_strlen, libicuuc) \
+    PER_FUNCTION_BLOCK(u_strncpy, libicuuc) \
+    PER_FUNCTION_BLOCK(u_tolower, libicuuc) \
+    PER_FUNCTION_BLOCK(u_toupper, libicuuc) \
+    PER_FUNCTION_BLOCK(ucal_add, libicui18n) \
+    PER_FUNCTION_BLOCK(ucal_close, libicui18n) \
+    PER_FUNCTION_BLOCK(ucal_get, libicui18n) \
+    PER_FUNCTION_BLOCK(ucal_getAttribute, libicui18n) \
+    PER_FUNCTION_BLOCK(ucal_getKeywordValuesForLocale, libicui18n) \
+    PER_FUNCTION_BLOCK(ucal_getLimit, libicui18n) \
+    PER_FUNCTION_BLOCK(ucal_getTimeZoneDisplayName, libicui18n) \
+    PER_FUNCTION_BLOCK(ucal_open, libicui18n) \
+    PER_FUNCTION_BLOCK(ucal_set, libicui18n) \
+    PER_FUNCTION_BLOCK(ucol_close, libicui18n) \
+    PER_FUNCTION_BLOCK(ucol_closeElements, libicui18n) \
+    PER_FUNCTION_BLOCK(ucol_getRules, libicui18n) \
+    PER_FUNCTION_BLOCK(ucol_getSortKey, libicui18n) \
+    PER_FUNCTION_BLOCK(ucol_getStrength, libicui18n) \
+    PER_FUNCTION_BLOCK(ucol_next, libicui18n) \
+    PER_FUNCTION_BLOCK(ucol_open, libicui18n) \
+    PER_FUNCTION_BLOCK(ucol_openElements, libicui18n) \
+    PER_FUNCTION_BLOCK(ucol_openRules, libicui18n) \
+    PER_FUNCTION_BLOCK(ucol_safeClone, libicui18n) \
+    PER_FUNCTION_BLOCK(ucol_setAttribute, libicui18n) \
+    PER_FUNCTION_BLOCK(ucol_strcoll, libicui18n) \
+    PER_FUNCTION_BLOCK(ucurr_forLocale, libicui18n) \
+    PER_FUNCTION_BLOCK(ucurr_getName, libicui18n) \
+    PER_FUNCTION_BLOCK(udat_close, libicui18n) \
+    PER_FUNCTION_BLOCK(udat_countSymbols, libicui18n) \
+    PER_FUNCTION_BLOCK(udat_getSymbols, libicui18n) \
+    PER_FUNCTION_BLOCK(udat_open, libicui18n) \
+    PER_FUNCTION_BLOCK(udat_setCalendar, libicui18n) \
+    PER_FUNCTION_BLOCK(udat_toPattern, libicui18n) \
+    PER_FUNCTION_BLOCK(udatpg_close, libicui18n) \
+    PER_FUNCTION_BLOCK(udatpg_getBestPattern, libicui18n) \
+    PER_FUNCTION_BLOCK(udatpg_open, libicui18n) \
+    PER_FUNCTION_BLOCK(uenum_close, libicuuc) \
+    PER_FUNCTION_BLOCK(uenum_count, libicuuc) \
+    PER_FUNCTION_BLOCK(uenum_next, libicuuc) \
+    PER_FUNCTION_BLOCK(uidna_close, libicuuc) \
+    PER_FUNCTION_BLOCK(uidna_nameToASCII, libicuuc) \
+    PER_FUNCTION_BLOCK(uidna_nameToUnicode, libicuuc) \
+    PER_FUNCTION_BLOCK(uidna_openUTS46, libicuuc) \
+    PER_FUNCTION_BLOCK(uldn_close, libicui18n) \
+    PER_FUNCTION_BLOCK(uldn_keyValueDisplayName, libicui18n) \
+    PER_FUNCTION_BLOCK(uldn_open, libicui18n) \
+    PER_FUNCTION_BLOCK(uloc_canonicalize, libicuuc) \
+    PER_FUNCTION_BLOCK(uloc_getBaseName, libicuuc) \
+    PER_FUNCTION_BLOCK(uloc_getCharacterOrientation, libicuuc) \
+    PER_FUNCTION_BLOCK(uloc_getCountry, libicuuc) \
+    PER_FUNCTION_BLOCK(uloc_getDefault, libicuuc) \
+    PER_FUNCTION_BLOCK(uloc_getDisplayCountry, libicuuc) \
+    PER_FUNCTION_BLOCK(uloc_getDisplayLanguage, libicuuc) \
+    PER_FUNCTION_BLOCK(uloc_getDisplayName, libicuuc) \
+    PER_FUNCTION_BLOCK(uloc_getISO3Country, libicuuc) \
+    PER_FUNCTION_BLOCK(uloc_getKeywordValue, libicuuc) \
+    PER_FUNCTION_BLOCK(uloc_getLanguage, libicuuc) \
+    PER_FUNCTION_BLOCK(uloc_getLCID, libicuuc) \
+    PER_FUNCTION_BLOCK(uloc_getName, libicuuc) \
+    PER_FUNCTION_BLOCK(uloc_getParent, libicuuc) \
+    PER_FUNCTION_BLOCK(uloc_setKeywordValue, libicuuc) \
+    PER_FUNCTION_BLOCK(ulocdata_getMeasurementSystem, libicui18n) \
+    PER_FUNCTION_BLOCK(unorm2_getNFCInstance, libicuuc) \
+    PER_FUNCTION_BLOCK(unorm2_getNFDInstance, libicuuc) \
+    PER_FUNCTION_BLOCK(unorm2_getNFKCInstance, libicuuc) \
+    PER_FUNCTION_BLOCK(unorm2_getNFKDInstance, libicuuc) \
+    PER_FUNCTION_BLOCK(unorm2_isNormalized, libicuuc) \
+    PER_FUNCTION_BLOCK(unorm2_normalize, libicuuc) \
+    PER_FUNCTION_BLOCK(unum_close, libicui18n) \
+    PER_FUNCTION_BLOCK(unum_getAttribute, libicui18n) \
+    PER_FUNCTION_BLOCK(unum_getSymbol, libicui18n) \
+    PER_FUNCTION_BLOCK(unum_open, libicui18n) \
+    PER_FUNCTION_BLOCK(unum_toPattern, libicui18n) \
+    PER_FUNCTION_BLOCK(ures_close, libicuuc) \
+    PER_FUNCTION_BLOCK(ures_getByKey, libicuuc) \
+    PER_FUNCTION_BLOCK(ures_getSize, libicuuc) \
+    PER_FUNCTION_BLOCK(ures_getStringByIndex, libicuuc) \
+    PER_FUNCTION_BLOCK(ures_open, libicuuc) \
+    PER_FUNCTION_BLOCK(usearch_close, libicui18n) \
+    PER_FUNCTION_BLOCK(usearch_first, libicui18n) \
+    PER_FUNCTION_BLOCK(usearch_getMatchedLength, libicui18n) \
+    PER_FUNCTION_BLOCK(usearch_last, libicui18n) \
+    PER_FUNCTION_BLOCK(usearch_openFromCollator, libicui18n)
+
+#if HAVE_SET_MAX_VARIABLE
+#define FOR_ALL_ICU_FUNCTIONS \
+    FOR_ALL_UNCONDITIONAL_ICU_FUNCTIONS \
+    PER_FUNCTION_BLOCK(ucol_setMaxVariable, libicui18n)
+#else
+#define FOR_ALL_ICU_FUNCTIONS \
+    FOR_ALL_UNCONDITIONAL_ICU_FUNCTIONS \
+    PER_FUNCTION_BLOCK(ucol_setVariableTop, libicui18n)
+#endif
+
+// Declare pointers to all the used ICU functions
+#define PER_FUNCTION_BLOCK(fn, lib) extern decltype(fn)* fn##_ptr;
+FOR_ALL_ICU_FUNCTIONS
+#undef PER_FUNCTION_BLOCK
+
+// Redefine all calls to ICU functions as calls through pointers that are set
+// to the functions of the selected version of ICU in the initialization.
+#define u_charsToUChars(...) u_charsToUChars_ptr(__VA_ARGS__)
+#define u_strlen(...) u_strlen_ptr(__VA_ARGS__)
+#define u_strncpy(...) u_strncpy_ptr(__VA_ARGS__)
+#define u_tolower(...) u_tolower_ptr(__VA_ARGS__)
+#define u_toupper(...) u_toupper_ptr(__VA_ARGS__)
+#define ucal_add(...) ucal_add_ptr(__VA_ARGS__)
+#define ucal_close(...) ucal_close_ptr(__VA_ARGS__)
+#define ucal_get(...) ucal_get_ptr(__VA_ARGS__)
+#define ucal_getAttribute(...) ucal_getAttribute_ptr(__VA_ARGS__)
+#define ucal_getKeywordValuesForLocale(...) ucal_getKeywordValuesForLocale_ptr(__VA_ARGS__)
+#define ucal_getLimit(...) ucal_getLimit_ptr(__VA_ARGS__)
+#define ucal_getTimeZoneDisplayName(...) ucal_getTimeZoneDisplayName_ptr(__VA_ARGS__)
+#define ucal_open(...) ucal_open_ptr(__VA_ARGS__)
+#define ucal_set(...) ucal_set_ptr(__VA_ARGS__)
+#define ucol_close(...) ucol_close_ptr(__VA_ARGS__)
+#define ucol_closeElements(...) ucol_closeElements_ptr(__VA_ARGS__)
+#define ucol_getRules(...) ucol_getRules_ptr(__VA_ARGS__)
+#define ucol_getSortKey(...) ucol_getSortKey_ptr(__VA_ARGS__)
+#define ucol_getStrength(...) ucol_getStrength_ptr(__VA_ARGS__)
+#define ucol_next(...) ucol_next_ptr(__VA_ARGS__)
+#define ucol_open(...) ucol_open_ptr(__VA_ARGS__)
+#define ucol_openElements(...) ucol_openElements_ptr(__VA_ARGS__)
+#define ucol_openRules(...) ucol_openRules_ptr(__VA_ARGS__)
+#define ucol_safeClone(...) ucol_safeClone_ptr(__VA_ARGS__)
+#define ucol_setAttribute(...) ucol_setAttribute_ptr(__VA_ARGS__)
+#if HAVE_SET_MAX_VARIABLE
+#define ucol_setMaxVariable(...) ucol_setMaxVariable_ptr(__VA_ARGS__)
+#else
+#define ucol_setVariableTop(...) ucol_setVariableTop_ptr(__VA_ARGS__)
+#endif
+#define ucol_strcoll(...) ucol_strcoll_ptr(__VA_ARGS__)
+#define ucurr_forLocale(...) ucurr_forLocale_ptr(__VA_ARGS__)
+#define ucurr_getName(...) ucurr_getName_ptr(__VA_ARGS__)
+#define udat_close(...) udat_close_ptr(__VA_ARGS__)
+#define udat_countSymbols(...) udat_countSymbols_ptr(__VA_ARGS__)
+#define udat_getSymbols(...) udat_getSymbols_ptr(__VA_ARGS__)
+#define udat_open(...) udat_open_ptr(__VA_ARGS__)
+#define udat_setCalendar(...) udat_setCalendar_ptr(__VA_ARGS__)
+#define udat_toPattern(...) udat_toPattern_ptr(__VA_ARGS__)
+#define udatpg_close(...) udatpg_close_ptr(__VA_ARGS__)
+#define udatpg_getBestPattern(...) udatpg_getBestPattern_ptr(__VA_ARGS__)
+#define udatpg_open(...) udatpg_open_ptr(__VA_ARGS__)
+#define uenum_close(...) uenum_close_ptr(__VA_ARGS__)
+#define uenum_count(...) uenum_count_ptr(__VA_ARGS__)
+#define uenum_next(...) uenum_next_ptr(__VA_ARGS__)
+#define uidna_close(...) uidna_close_ptr(__VA_ARGS__)
+#define uidna_nameToASCII(...) uidna_nameToASCII_ptr(__VA_ARGS__)
+#define uidna_nameToUnicode(...) uidna_nameToUnicode_ptr(__VA_ARGS__)
+#define uidna_openUTS46(...) uidna_openUTS46_ptr(__VA_ARGS__)
+#define uldn_close(...) uldn_close_ptr(__VA_ARGS__)
+#define uldn_keyValueDisplayName(...) uldn_keyValueDisplayName_ptr(__VA_ARGS__)
+#define uldn_open(...) uldn_open_ptr(__VA_ARGS__)
+#define uloc_canonicalize(...) uloc_canonicalize_ptr(__VA_ARGS__)
+#define uloc_getBaseName(...) uloc_getBaseName_ptr(__VA_ARGS__)
+#define uloc_getCharacterOrientation(...) uloc_getCharacterOrientation_ptr(__VA_ARGS__)
+#define uloc_getCountry(...) uloc_getCountry_ptr(__VA_ARGS__)
+#define uloc_getDefault(...) uloc_getDefault_ptr(__VA_ARGS__)
+#define uloc_getDisplayCountry(...) uloc_getDisplayCountry_ptr(__VA_ARGS__)
+#define uloc_getDisplayLanguage(...) uloc_getDisplayLanguage_ptr(__VA_ARGS__)
+#define uloc_getDisplayName(...) uloc_getDisplayName_ptr(__VA_ARGS__)
+#define uloc_getISO3Country(...) uloc_getISO3Country_ptr(__VA_ARGS__)
+#define uloc_getKeywordValue(...) uloc_getKeywordValue_ptr(__VA_ARGS__)
+#define uloc_getLanguage(...) uloc_getLanguage_ptr(__VA_ARGS__)
+#define uloc_getLCID(...) uloc_getLCID_ptr(__VA_ARGS__)
+#define uloc_getName(...) uloc_getName_ptr(__VA_ARGS__)
+#define uloc_getParent(...) uloc_getParent_ptr(__VA_ARGS__)
+#define uloc_setKeywordValue(...) uloc_setKeywordValue_ptr(__VA_ARGS__)
+#define ulocdata_getMeasurementSystem(...) ulocdata_getMeasurementSystem_ptr(__VA_ARGS__)
+#define unorm2_getNFCInstance(...) unorm2_getNFCInstance_ptr(__VA_ARGS__)
+#define unorm2_getNFDInstance(...) unorm2_getNFDInstance_ptr(__VA_ARGS__)
+#define unorm2_getNFKCInstance(...) unorm2_getNFKCInstance_ptr(__VA_ARGS__)
+#define unorm2_getNFKDInstance(...) unorm2_getNFKDInstance_ptr(__VA_ARGS__)
+#define unorm2_isNormalized(...) unorm2_isNormalized_ptr(__VA_ARGS__)
+#define unorm2_normalize(...) unorm2_normalize_ptr(__VA_ARGS__)
+#define unum_close(...) unum_close_ptr(__VA_ARGS__)
+#define unum_getAttribute(...) unum_getAttribute_ptr(__VA_ARGS__)
+#define unum_getSymbol(...) unum_getSymbol_ptr(__VA_ARGS__)
+#define unum_open(...) unum_open_ptr(__VA_ARGS__)
+#define unum_toPattern(...) unum_toPattern_ptr(__VA_ARGS__)
+#define ures_close(...) ures_close_ptr(__VA_ARGS__)
+#define ures_getByKey(...) ures_getByKey_ptr(__VA_ARGS__)
+#define ures_getSize(...) ures_getSize_ptr(__VA_ARGS__)
+#define ures_getStringByIndex(...) ures_getStringByIndex_ptr(__VA_ARGS__)
+#define ures_open(...) ures_open_ptr(__VA_ARGS__)
+#define usearch_close(...) usearch_close_ptr(__VA_ARGS__)
+#define usearch_first(...) usearch_first_ptr(__VA_ARGS__)
+#define usearch_getMatchedLength(...) usearch_getMatchedLength_ptr(__VA_ARGS__)
+#define usearch_last(...) usearch_last_ptr(__VA_ARGS__)
+#define usearch_openFromCollator(...) usearch_openFromCollator_ptr(__VA_ARGS__)
+
+#endif // !FEATURE_ICU_VERSION_RESILIENT
+
+#endif // __ICUSHIM_H__
diff --git a/src/corefx/System.Globalization.Native/idna.cpp b/src/corefx/System.Globalization.Native/idna.cpp
index 4820d2c3f2..23942b3a68 100644
--- a/src/corefx/System.Globalization.Native/idna.cpp
+++ b/src/corefx/System.Globalization.Native/idna.cpp
@@ -4,7 +4,7 @@
 //
 
 #include <stdint.h>
-#include <unicode/uidna.h>
+#include "icushim.h"
 
 const uint32_t AllowUnassigned = 0x1;
 const uint32_t UseStd3AsciiRules = 0x2;
diff --git a/src/corefx/System.Globalization.Native/locale.cpp b/src/corefx/System.Globalization.Native/locale.cpp
index 1cb564a45a..0a85ae1873 100644
--- a/src/corefx/System.Globalization.Native/locale.cpp
+++ b/src/corefx/System.Globalization.Native/locale.cpp
@@ -9,6 +9,7 @@
 #include <stdlib.h>
 #include <locale.h>
 
+#include "icushim.h"
 #include "locale.hpp"
 
 int32_t UErrorCodeToBool(UErrorCode status)
diff --git a/src/corefx/System.Globalization.Native/locale.hpp b/src/corefx/System.Globalization.Native/locale.hpp
index ac28fb1e02..79328f3b19 100644
--- a/src/corefx/System.Globalization.Native/locale.hpp
+++ b/src/corefx/System.Globalization.Native/locale.hpp
@@ -2,9 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#include "unicode/locid.h"
-#include "unicode/ucurr.h"
-
 /*
 Function:
 UErrorCodeToBool
diff --git a/src/corefx/System.Globalization.Native/localeNumberData.cpp b/src/corefx/System.Globalization.Native/localeNumberData.cpp
index 595cb130b2..a3586b568f 100644
--- a/src/corefx/System.Globalization.Native/localeNumberData.cpp
+++ b/src/corefx/System.Globalization.Native/localeNumberData.cpp
@@ -7,8 +7,7 @@
 #include <string.h>
 #include <vector>
 
-#include <unicode/ulocdata.h>
-
+#include "icushim.h"
 #include "locale.hpp"
 #include "holders.h"
 
diff --git a/src/corefx/System.Globalization.Native/localeStringData.cpp b/src/corefx/System.Globalization.Native/localeStringData.cpp
index a8dcc519ad..54ef8f02f1 100644
--- a/src/corefx/System.Globalization.Native/localeStringData.cpp
+++ b/src/corefx/System.Globalization.Native/localeStringData.cpp
@@ -7,6 +7,7 @@
 #include <string.h>
 #include <vector>
 
+#include "icushim.h"
 #include "locale.hpp"
 #include "holders.h"
 
diff --git a/src/corefx/System.Globalization.Native/normalization.cpp b/src/corefx/System.Globalization.Native/normalization.cpp
index f96f5ee315..014894a5ed 100644
--- a/src/corefx/System.Globalization.Native/normalization.cpp
+++ b/src/corefx/System.Globalization.Native/normalization.cpp
@@ -4,7 +4,7 @@
 //
 
 #include <stdint.h>
-#include <unicode/unorm2.h>
+#include "icushim.h"
 
 /*
  * These values should be kept in sync with System.Text.NormalizationForm
diff --git a/src/corefx/System.Globalization.Native/timeZoneInfo.cpp b/src/corefx/System.Globalization.Native/timeZoneInfo.cpp
index d0e01e5ce6..0dd28b4b70 100644
--- a/src/corefx/System.Globalization.Native/timeZoneInfo.cpp
+++ b/src/corefx/System.Globalization.Native/timeZoneInfo.cpp
@@ -5,8 +5,8 @@
 
 #include <stdint.h>
 #include <unistd.h>
-#include <unicode/ucal.h>
 
+#include "icushim.h"
 #include "locale.hpp"
 #include "holders.h"
 #include "errors.h"