Fallback fonts can have first crack at adding an unknown character + set Twemoji as the viewer's fallback for all emoji blocks

16 files changed, 333 insertions, 101 deletions

diff --git a/autobuild.xml b/autobuild.xml
index 8bd6491edd..131c7614c0 100644
--- a/autobuild.xml
+++ b/autobuild.xml
@@ -1519,6 +1519,96 @@
         <key>version</key>
         <string>2012.1-2</string>
       </map>
+      <key>icu4c</key>
+      <map>
+        <key>copyright</key>
+        <string>Copyright (c) 1995-2011 International Business Machines Corporation and others &lt;http://source.icu-project.org&gt;</string>
+        <key>description</key>
+        <string>ICU is a mature, widely used set of C/C++ and Java libraries providing Unicode and Globalization support for software applications. ICU is widely portable and gives applications the same results on all platforms and between C/C++ and Java software.</string>
+        <key>license</key>
+        <string>ICU, permissive non-copyleft free software license</string>
+        <key>license_file</key>
+        <string>LICENSES/icu.txt</string>
+        <key>name</key>
+        <string>icu4c</string>
+        <key>platforms</key>
+        <map>
+          <key>darwin</key>
+          <map>
+            <key>archive</key>
+            <map>
+              <key>hash</key>
+              <string>910edfc0b936389bc8804c42d1008aa8</string>
+              <key>url</key>
+              <string>http://automated-builds-secondlife-com.s3.amazonaws.com/hg/repo/icu4c_3p-update-icu4c/rev/295486/arch/Darwin/installer/icu4c-4.8.1-darwin-295486.tar.bz2</string>
+            </map>
+            <key>name</key>
+            <string>windows64</string>
+          </map>
+          <key>darwin64</key>
+          <map>
+            <key>archive</key>
+            <map>
+              <key>hash</key>
+              <string>2c34cb4e62d1f155d5dad798e69d03c8</string>
+              <key>url</key>
+              <string>http://automated-builds-secondlife-com.s3.amazonaws.com/ct2/466/1005/icu4c-4.8.1-darwin64-500388.tar.bz2</string>
+            </map>
+            <key>name</key>
+            <string>windows64</string>
+          </map>
+          <key>linux</key>
+          <map>
+            <key>archive</key>
+            <map>
+              <key>hash</key>
+              <string>0a4423cfd26409f33ae81fb9806a9972</string>
+              <key>url</key>
+              <string>http://automated-builds-secondlife-com.s3.amazonaws.com/hg/repo/p64_3p-icu4c/rev/314152/arch/Linux/installer/icu4c-4.8.1-linux-314152.tar.bz2</string>
+            </map>
+            <key>name</key>
+            <string>windows64</string>
+          </map>
+          <key>linux64</key>
+          <map>
+            <key>archive</key>
+            <map>
+              <key>hash</key>
+              <string>b327031733c36efe2eee4582aefb2d66</string>
+              <key>url</key>
+              <string>http://automated-builds-secondlife-com.s3.amazonaws.com/ct2/462/995/icu4c-4.8.1-linux64-500388.tar.bz2</string>
+            </map>
+            <key>name</key>
+            <string>windows64</string>
+          </map>
+          <key>windows</key>
+          <map>
+            <key>archive</key>
+            <map>
+              <key>hash</key>
+          <string>af354f6ab6d2cecf266c79031977e3e0</string>
+          <key>url</key>
+          <string>http://automated-builds-secondlife-com.s3.amazonaws.com/ct2/492/1078/icu4c-4.8.1-windows-500388.tar.bz2</string>
+            </map>
+            <key>name</key>
+            <string>windows64</string>
+          </map>
+          <key>windows64</key>
+          <map>
+            <key>archive</key>
+            <map>
+              <key>hash</key>
+              <string>e8b20cea748b90ea18bb63dfba06e059</string>
+              <key>url</key>
+              <string>http://automated-builds-secondlife-com.s3.amazonaws.com/ct2/491/1075/icu4c-4.8.1-windows64-500388.tar.bz2</string>
+            </map>
+            <key>name</key>
+            <string>windows64</string>
+          </map>
+        </map>
+        <key>version</key>
+        <string>4.8.1</string>
+      </map>
       <key>jpeglib</key>
       <map>
         <key>copyright</key>
diff --git a/indra/cmake/CMakeLists.txt b/indra/cmake/CMakeLists.txt
index 84e1c5d6fd..d64c38b1b3 100644
--- a/indra/cmake/CMakeLists.txt
+++ b/indra/cmake/CMakeLists.txt
@@ -32,6 +32,7 @@ set(cmake_SOURCE_FILES
     FindGLH.cmake
     FindGoogleBreakpad.cmake
     FindHUNSPELL.cmake
+    FindICU4C.cmake
     FindJsonCpp.cmake
     FindNDOF.cmake
     FindOpenJPEG.cmake
@@ -49,6 +50,7 @@ set(cmake_SOURCE_FILES
     GoogleMock.cmake
     Havok.cmake
     Hunspell.cmake
+    ICU4C.cmake
     JPEG.cmake
     JsonCpp.cmake
     LLAddBuildTest.cmake
diff --git a/indra/cmake/FindICU4C.cmake b/indra/cmake/FindICU4C.cmake
new file mode 100644
index 0000000000..327d761a88
--- /dev/null
+++ b/indra/cmake/FindICU4C.cmake
@@ -0,0 +1,33 @@
+# -*- cmake -*-
+
+# - Find ICU4C
+# This module defines
+#  ICU4C_INCLUDE_DIR, where to find headers
+#  ICU4C_LIBRARY, the library needed to use ICU4C.
+#  ICU4C_FOUND, If false, do not try to use ICU4C.
+
+find_path(ICU4C_INCLUDE_DIR uchar.h
+  PATH_SUFFIXES unicode
+  )
+
+set(ICU4C_NAMES ${ICU4C_NAMES} icuuc)
+find_library(ICU4C_LIBRARY
+  NAMES ${ICU4C_NAMES}
+  )
+
+if (ICU4C_LIBRARY AND ICU4C_INCLUDE_DIR)
+  set(ICU4C_FOUND "YES")
+else (ICU4C_LIBRARY AND ICU4C_INCLUDE_DIR)
+  set(ICU4C_FOUND "NO")
+endif (ICU4C_LIBRARY AND ICU4C_INCLUDE_DIR)
+
+if (ICU4C_FOUND)
+    message(STATUS "Found ICU4C: Library in '${ICU4C_LIBRARY}' and header in '${ICU4C_INCLUDE_DIR}' ")
+else (ICU4C_FOUND)
+    message(FATAL_ERROR " * * *\nCould not find ICU4C library! * * *")
+endif (ICU4C_FOUND)
+
+mark_as_advanced(
+  ICU4C_LIBRARY
+  ICU4C_INCLUDE_DIR
+  )
diff --git a/indra/cmake/ICU4C.cmake b/indra/cmake/ICU4C.cmake
new file mode 100644
index 0000000000..007a9b6937
--- /dev/null
+++ b/indra/cmake/ICU4C.cmake
@@ -0,0 +1,22 @@
+# -*- cmake -*-
+include(Prebuilt)
+
+set(ICU4C_FIND_QUIETLY ON)
+set(ICU4C_FIND_REQUIRED ON)
+
+if (USESYSTEMLIBS)
+  include(FindICU4C)
+else (USESYSTEMLIBS)
+  use_prebuilt_binary(icu4c)
+  if (WINDOWS)
+    set(ICU4C_LIBRARY icuuc)
+  #elseif(DARWIN)
+  #  set(ICU4C_LIBRARY ...)
+  #elseif(LINUX)
+  #  set(ICU4C_LIBRARY ...)
+  else()
+    message(FATAL_ERROR "Invalid platform")
+  endif()
+  set(ICU4C_INCLUDE_DIRS ${LIBS_PREBUILT_DIR}/include/unicode)
+  use_prebuilt_binary(dictionaries)
+endif (USESYSTEMLIBS)
diff --git a/indra/llcommon/CMakeLists.txt b/indra/llcommon/CMakeLists.txt
index af41b9e460..ba87d93fec 100644
--- a/indra/llcommon/CMakeLists.txt
+++ b/indra/llcommon/CMakeLists.txt
@@ -4,6 +4,7 @@
 project(llcommon)
 
 include(00-Common)
+include(ICU4C)
 include(LLCommon)
 include(Linking)
 include(Boost)
@@ -288,6 +289,7 @@ target_link_libraries(
     ${APRUTIL_LIBRARIES}
     ${APR_LIBRARIES}
     ${EXPAT_LIBRARIES}
+    ${ICU4C_LIBRARY}
     ${JSONCPP_LIBRARIES}
     ${ZLIB_LIBRARIES}
     ${WINDOWS_LIBRARIES}
diff --git a/indra/llcommon/llstring.cpp b/indra/llcommon/llstring.cpp
index 0174c411b4..b272728200 100644
--- a/indra/llcommon/llstring.cpp
+++ b/indra/llcommon/llstring.cpp
@@ -30,6 +30,7 @@
 #include "llerror.h"
 #include "llfasttimer.h"
 #include "llsd.h"
+#include <unicode/uchar.h>
 #include <vector>
 
 #if LL_WINDOWS
@@ -888,6 +889,31 @@ std::string LLStringOps::sDayFormat;
 std::string LLStringOps::sAM;
 std::string LLStringOps::sPM;
 
+// static
+bool LLStringOps::isEmoji(llwchar wch)
+{
+	switch (ublock_getCode(wch))
+	{
+		case UBLOCK_MISCELLANEOUS_SYMBOLS:
+		case UBLOCK_DINGBATS:
+		case UBLOCK_MISCELLANEOUS_SYMBOLS_AND_PICTOGRAPHS:
+		case UBLOCK_EMOTICONS:
+		case UBLOCK_TRANSPORT_AND_MAP_SYMBOLS:
+#if U_ICU_VERSION_MAJOR_NUM > 56
+		// Boost uses ICU so we can't update it independently
+		case UBLOCK_SUPPLEMENTAL_SYMBOLS_AND_PICTOGRAPHS:
+#endif // U_ICU_VERSION_MAJOR_NUM > 56
+			return true;
+		default:
+#if U_ICU_VERSION_MAJOR_NUM > 56
+			return false;
+#else
+			// See https://en.wikipedia.org/wiki/Supplemental_Symbols_and_Pictographs
+			return wch >= 0x1F900 && wch <= 0x1F9FF;
+#endif // U_ICU_VERSION_MAJOR_NUM > 56
+	}
+}
+
 
 S32	LLStringOps::collate(const llwchar* a, const llwchar* b)
 { 
diff --git a/indra/llcommon/llstring.h b/indra/llcommon/llstring.h
index b619a9e48c..d31d0cafc7 100644
--- a/indra/llcommon/llstring.h
+++ b/indra/llcommon/llstring.h
@@ -193,6 +193,8 @@ public:
 	static bool isAlnum(char a) { return isalnum((unsigned char)a) != 0; }
 	static bool isAlnum(llwchar a) { return iswalnum(a) != 0; }
 
+	static bool isEmoji(llwchar wch);
+
 	static S32	collate(const char* a, const char* b) { return strcoll(a, b); }
 	static S32	collate(const llwchar* a, const llwchar* b);
 
diff --git a/indra/llrender/llfontfreetype.cpp b/indra/llrender/llfontfreetype.cpp
index 7d66965e57..25740a5f87 100644
--- a/indra/llrender/llfontfreetype.cpp
+++ b/indra/llrender/llfontfreetype.cpp
@@ -175,7 +175,7 @@ void ft_close_cb(FT_Stream stream) {
 }
 #endif
 
-BOOL LLFontFreetype::loadFace(const std::string& filename, F32 point_size, F32 vert_dpi, F32 horz_dpi, bool use_color, bool is_fallback, S32 face_n)
+BOOL LLFontFreetype::loadFace(const std::string& filename, F32 point_size, F32 vert_dpi, F32 horz_dpi, bool is_fallback, S32 face_n)
 {
 	// Don't leak face objects.  This is also needed to deal with
 	// changed font file names.
@@ -345,14 +345,11 @@ void LLFontFreetype::clearFontStreams()
 }
 #endif
 
-void LLFontFreetype::setFallbackFonts(const font_vector_t &font)
+void LLFontFreetype::addFallbackFont(const LLPointer<LLFontFreetype>& fallback_font, const char_functor_t& functor)
 {
-	mFallbackFonts = font;
-}
-
-const LLFontFreetype::font_vector_t &LLFontFreetype::getFallbackFonts() const
-{
-	return mFallbackFonts;
+	// Insert functor fallbacks before generic fallbacks
+	mFallbackFonts.insert((functor) ? std::find_if(mFallbackFonts.begin(), mFallbackFonts.end(), [](const fallback_font_t& fe) { return !fe.second; }) : mFallbackFonts.end(),
+	                      std::make_pair(fallback_font, functor));
 }
 
 F32 LLFontFreetype::getLineHeight() const
@@ -453,18 +450,31 @@ LLFontGlyphInfo* LLFontFreetype::addGlyph(llwchar wch, EFontGlyphType glyph_type
 
 	FT_UInt glyph_index;
 
+	// Fallback fonts with a functor have precedence over everything else
+	fallback_font_vector_t::const_iterator it_fallback = mFallbackFonts.cbegin();
+	for (; it_fallback != mFallbackFonts.cend() && it_fallback->second; ++it_fallback)
+	{
+		if (it_fallback->second(wch))
+		{
+			glyph_index = FT_Get_Char_Index(it_fallback->first->mFTFace, wch);
+			if (glyph_index)
+			{
+				return addGlyphFromFont(it_fallback->first, wch, glyph_index, glyph_type);
+			}
+		}
+	}
+
 	// Initialize char to glyph map
 	glyph_index = FT_Get_Char_Index(mFTFace, wch);
 	if (glyph_index == 0)
 	{
 		//LL_INFOS() << "Trying to add glyph from fallback font!" << LL_ENDL;
-		font_vector_t::const_iterator iter;
-		for(iter = mFallbackFonts.begin(); iter != mFallbackFonts.end(); iter++)
+		for (; it_fallback != mFallbackFonts.cend(); ++it_fallback)
 		{
-			glyph_index = FT_Get_Char_Index((*iter)->mFTFace, wch);
+			glyph_index = FT_Get_Char_Index(it_fallback->first->mFTFace, wch);
 			if (glyph_index)
 			{
-				return addGlyphFromFont(*iter, wch, glyph_index, glyph_type);
+				return addGlyphFromFont(it_fallback->first, wch, glyph_index, glyph_type);
 			}
 		}
 	}
@@ -653,7 +663,7 @@ void LLFontFreetype::renderGlyph(EFontGlyphType bitmap_type, U32 glyph_index) co
 void LLFontFreetype::reset(F32 vert_dpi, F32 horz_dpi)
 {
 	resetBitmapCache(); 
-	loadFace(mName, mPointSize, vert_dpi ,horz_dpi, true, mIsFallback, 0);
+	loadFace(mName, mPointSize, vert_dpi ,horz_dpi, mIsFallback, 0);
 	if (!mIsFallback)
 	{
 		// This is the head of the list - need to rebuild ourself and all fallbacks.
@@ -663,11 +673,9 @@ void LLFontFreetype::reset(F32 vert_dpi, F32 horz_dpi)
 		}
 		else
 		{
-			for(font_vector_t::iterator it = mFallbackFonts.begin();
-				it != mFallbackFonts.end();
-				++it)
+			for (fallback_font_vector_t::iterator it = mFallbackFonts.begin(); it != mFallbackFonts.end(); ++it)
 			{
-				(*it)->reset(vert_dpi, horz_dpi);
+				it->first->reset(vert_dpi, horz_dpi);
 			}
 		}
 	}
diff --git a/indra/llrender/llfontfreetype.h b/indra/llrender/llfontfreetype.h
index 8c2d2bc491..8afc5e3ed5 100644
--- a/indra/llrender/llfontfreetype.h
+++ b/indra/llrender/llfontfreetype.h
@@ -86,7 +86,7 @@ public:
 
 	// is_fallback should be true for fallback fonts that aren't used
 	// to render directly (Unicode backup, primarily)
-	BOOL loadFace(const std::string& filename, F32 point_size, F32 vert_dpi, F32 horz_dpi, bool use_color, bool is_fallback, S32 face_n);
+	BOOL loadFace(const std::string& filename, F32 point_size, F32 vert_dpi, F32 horz_dpi, bool is_fallback, S32 face_n);
 
 	S32 getNumFaces(const std::string& filename);
 
@@ -95,10 +95,8 @@ public:
 	void clearFontStreams();
 #endif
 
-	typedef std::vector<LLPointer<LLFontFreetype> > font_vector_t;
-
-	void setFallbackFonts(const font_vector_t &font);
-	const font_vector_t &getFallbackFonts() const;
+	typedef std::function<bool(llwchar)> char_functor_t;
+	void addFallbackFont(const LLPointer<LLFontFreetype>& fallback_font, const char_functor_t& functor = nullptr);
 
 	// Global font metrics - in units of pixels
 	F32 getLineHeight() const;
@@ -178,7 +176,9 @@ private:
 #endif
 
 	BOOL mIsFallback;
-	font_vector_t mFallbackFonts; // A list of fallback fonts to look for glyphs in (for Unicode chars)
+	typedef std::pair<LLPointer<LLFontFreetype>, char_functor_t> fallback_font_t;
+	typedef std::vector<fallback_font_t> fallback_font_vector_t;
+	fallback_font_vector_t mFallbackFonts; // A list of fallback fonts to look for glyphs in (for Unicode chars)
 
 	// *NOTE: the same glyph can be present with multiple representations (but the pointer is always unique)
 	typedef boost::unordered_multimap<llwchar, LLFontGlyphInfo*> char_glyph_info_map_t;
diff --git a/indra/llrender/llfontgl.cpp b/indra/llrender/llfontgl.cpp
index 78017ecb3d..4770f79395 100644
--- a/indra/llrender/llfontgl.cpp
+++ b/indra/llrender/llfontgl.cpp
@@ -89,14 +89,14 @@ void LLFontGL::destroyGL()
 	mFontFreetype->destroyGL();
 }
 
-BOOL LLFontGL::loadFace(const std::string& filename, F32 point_size, const F32 vert_dpi, const F32 horz_dpi, bool use_color, bool is_fallback, S32 face_n)
+BOOL LLFontGL::loadFace(const std::string& filename, F32 point_size, const F32 vert_dpi, const F32 horz_dpi, bool is_fallback, S32 face_n)
 {
 	if(mFontFreetype == reinterpret_cast<LLFontFreetype*>(NULL))
 	{
 		mFontFreetype = new LLFontFreetype;
 	}
 
-	return mFontFreetype->loadFace(filename, point_size, vert_dpi, horz_dpi, use_color, is_fallback, face_n);
+	return mFontFreetype->loadFace(filename, point_size, vert_dpi, horz_dpi, is_fallback, face_n);
 }
 
 S32 LLFontGL::getNumFaces(const std::string& filename)
diff --git a/indra/llrender/llfontgl.h b/indra/llrender/llfontgl.h
index 68bf5db668..a60feb87cb 100644
--- a/indra/llrender/llfontgl.h
+++ b/indra/llrender/llfontgl.h
@@ -87,7 +87,7 @@ public:
 
 	void destroyGL();
 
-	BOOL loadFace(const std::string& filename, F32 point_size, const F32 vert_dpi, const F32 horz_dpi, bool use_color, bool is_fallback, S32 face_n);
+	BOOL loadFace(const std::string& filename, F32 point_size, const F32 vert_dpi, const F32 horz_dpi, bool is_fallback, S32 face_n);
 
 	S32 getNumFaces(const std::string& filename);
 
diff --git a/indra/llrender/llfontregistry.cpp b/indra/llrender/llfontregistry.cpp
index 426b10b016..ac2b695a3e 100644
--- a/indra/llrender/llfontregistry.cpp
+++ b/indra/llrender/llfontregistry.cpp
@@ -46,6 +46,10 @@ bool init_from_xml(LLFontRegistry* registry, LLXMLNodePtr node);
 
 const std::string MACOSX_FONT_PATH_LIBRARY = "/Library/Fonts/";
 
+LLFontDescriptor::char_functor_map_t LLFontDescriptor::mCharFunctors({
+	{ "is_emoji", LLStringOps::isEmoji }
+});
+
 LLFontDescriptor::LLFontDescriptor():
 	mStyle(0)
 {
@@ -54,22 +58,22 @@ LLFontDescriptor::LLFontDescriptor():
 LLFontDescriptor::LLFontDescriptor(const std::string& name,
 								   const std::string& size, 
 								   const U8 style,
-								   const string_vec_t& file_names):
+								   const font_file_info_vec_t& font_files):
 	mName(name),
 	mSize(size),
 	mStyle(style),
-	mFileNames(file_names)
+	mFontFiles(font_files)
 {
 }
 
 LLFontDescriptor::LLFontDescriptor(const std::string& name,
 	const std::string& size,
 	const U8 style,
-	const string_vec_t& file_names,
-	const string_vec_t& ft_collection_listections) :
-	LLFontDescriptor(name, size, style, file_names)
+	const font_file_info_vec_t& font_list,
+	const font_file_info_vec_t& font_collection_files) :
+	LLFontDescriptor(name, size, style, font_list)
 {
-	mFontCollectionsList = ft_collection_listections;
+	mFontCollectionFiles = font_collection_files;
 }
 
 LLFontDescriptor::LLFontDescriptor(const std::string& name,
@@ -81,7 +85,6 @@ LLFontDescriptor::LLFontDescriptor(const std::string& name,
 {
 }
 
-
 bool LLFontDescriptor::operator<(const LLFontDescriptor& b) const
 {
 	if (mName < b.mName)
@@ -174,7 +177,19 @@ LLFontDescriptor LLFontDescriptor::normalize() const
 	if (removeSubString(new_name,"Italic"))
 		new_style |= LLFontGL::ITALIC;
 
-	return LLFontDescriptor(new_name,new_size,new_style,getFileNames(),getFontCollectionsList());
+	return LLFontDescriptor(new_name,new_size,new_style, getFontFiles(), getFontCollectionFiles());
+}
+
+void LLFontDescriptor::addFontFile(const std::string& file_name, const std::string& char_functor)
+{
+	char_functor_map_t::const_iterator it = mCharFunctors.find(char_functor);
+	mFontFiles.push_back(LLFontFileInfo(file_name, (mCharFunctors.end() != it) ? it->second : nullptr));
+}
+
+void LLFontDescriptor::addFontCollectionFile(const std::string& file_name, const std::string& char_functor)
+{
+	char_functor_map_t::const_iterator it = mCharFunctors.find(char_functor);
+	mFontCollectionFiles.push_back(LLFontFileInfo(file_name, (mCharFunctors.end() != it) ? it->second : nullptr));
 }
 
 LLFontRegistry::LLFontRegistry(bool create_gl_textures)
@@ -272,17 +287,24 @@ bool font_desc_init_from_xml(LLXMLNodePtr node, LLFontDescriptor& desc)
 		if (child->hasName("file"))
 		{
 			std::string font_file_name = child->getTextContents();
-			desc.getFileNames().push_back(font_file_name);
-			
+			std::string char_functor;
+
+			if (child->hasAttribute("functor"))
+			{
+				child->getAttributeString("functor", char_functor);
+			}
+
 			if (child->hasAttribute("load_collection"))
 			{
 				BOOL col = FALSE;
 				child->getAttributeBOOL("load_collection", col);
 				if (col)
 				{
-					desc.getFontCollectionsList().push_back(font_file_name);
+					desc.addFontCollectionFile(font_file_name, char_functor);
 				}
 			}
+
+			desc.addFontFile(font_file_name, char_functor);
 		}
 		else if (child->hasName("os"))
 		{
@@ -325,19 +347,19 @@ bool init_from_xml(LLFontRegistry* registry, LLXMLNodePtr node)
 					// A little roundabout because the map key is const,
 					// so we have to fetch it, make a new map key, and
 					// replace the old entry.
-					string_vec_t match_file_names = match_desc->getFileNames();
-					match_file_names.insert(match_file_names.begin(),
-											desc.getFileNames().begin(),
-											desc.getFileNames().end());
+					font_file_info_vec_t font_files = match_desc->getFontFiles();
+					font_files.insert(font_files.begin(),
+									  desc.getFontFiles().begin(),
+									  desc.getFontFiles().end());
 
-					string_vec_t collections_list = match_desc->getFontCollectionsList();
-					collections_list.insert(collections_list.begin(),
-						desc.getFontCollectionsList().begin(),
-						desc.getFontCollectionsList().end());
+					font_file_info_vec_t font_collection_files = match_desc->getFontCollectionFiles();
+					font_collection_files.insert(font_collection_files.begin(),
+						desc.getFontCollectionFiles().begin(),
+						desc.getFontCollectionFiles().end());
 
 					LLFontDescriptor new_desc = *match_desc;
-					new_desc.getFileNames() = match_file_names;
-					new_desc.getFontCollectionsList() = collections_list;
+					new_desc.setFontFiles(font_files);
+					new_desc.setFontCollectionFiles(font_collection_files);
 					registry->mFontMap.erase(*match_desc);
 					registry->mFontMap[new_desc] = NULL;
 				}
@@ -422,80 +444,78 @@ LLFontGL *LLFontRegistry::createFont(const LLFontDescriptor& desc)
 
 	// Build list of font names to look for.
 	// Files specified for this font come first, followed by those from the default descriptor.
-	string_vec_t file_names = match_desc->getFileNames();
-	string_vec_t ft_collection_list = match_desc->getFontCollectionsList();
-	string_vec_t default_file_names;
+	font_file_info_vec_t font_files = match_desc->getFontFiles();
+	font_file_info_vec_t font_collection_files = match_desc->getFontCollectionFiles();
 	LLFontDescriptor default_desc("default",s_template_string,0);
 	const LLFontDescriptor *match_default_desc = getMatchingFontDesc(default_desc);
 	if (match_default_desc)
 	{
-		file_names.insert(file_names.end(),
-						  match_default_desc->getFileNames().begin(),
-						  match_default_desc->getFileNames().end());
-		ft_collection_list.insert(ft_collection_list.end(),
-			match_default_desc->getFontCollectionsList().begin(),
-			match_default_desc->getFontCollectionsList().end());
+		font_files.insert(font_files.end(),
+						  match_default_desc->getFontFiles().begin(),
+						  match_default_desc->getFontFiles().end());
+		font_collection_files.insert(font_collection_files.end(),
+			match_default_desc->getFontCollectionFiles().begin(),
+			match_default_desc->getFontCollectionFiles().end());
 	}
 
 	// Add ultimate fallback list - generated dynamically on linux,
 	// null elsewhere.
-	file_names.insert(file_names.end(),
-					  getUltimateFallbackList().begin(),
-					  getUltimateFallbackList().end());
+	std::transform(getUltimateFallbackList().begin(), getUltimateFallbackList().end(), std::back_inserter(font_files),
+	               [](const std::string& file_name) { return LLFontFileInfo(file_name); });
 
 	// Load fonts based on names.
-	if (file_names.empty())
+	if (font_files.empty())
 	{
 		LL_WARNS() << "createFont failed, no file names specified" << LL_ENDL;
 		return NULL;
 	}
 
-	LLFontFreetype::font_vector_t fontlist;
 	LLFontGL *result = NULL;
 
-	// Snarf all fonts we can into fontlist.  First will get pulled
-	// off the list and become the "head" font, set to non-fallback.
+	// The first font will get pulled will be the "head" font, set to non-fallback.
 	// Rest will consitute the fallback list.
 	BOOL is_first_found = TRUE;
 	
-	std::string local_path = LLFontGL::getFontPathLocal();
-	std::string sys_path = LLFontGL::getFontPathSystem();
-	
+	string_vec_t font_search_paths;
+	font_search_paths.push_back(LLFontGL::getFontPathLocal());
+	font_search_paths.push_back(LLFontGL::getFontPathSystem());
+#if LL_DARWIN
+	font_search_paths.push_back(MACOSX_FONT_PATH_LIBRARY);
+#endif
+
 	// The fontname string may contain multiple font file names separated by semicolons.
 	// Break it apart and try loading each one, in order.
-	for(string_vec_t::iterator file_name_it = file_names.begin();
-		file_name_it != file_names.end(); 
-		++file_name_it)
+	for(font_file_info_vec_t::iterator font_file_it = font_files.begin();
+		font_file_it != font_files.end();
+		++font_file_it)
 	{
 		LLFontGL *fontp = NULL;
-		string_vec_t font_paths;
-		font_paths.push_back(local_path + *file_name_it);
-		font_paths.push_back(sys_path + *file_name_it);
-#if LL_DARWIN
-		font_paths.push_back(MACOSX_FONT_PATH_LIBRARY + *file_name_it);
-#endif
-		
-		bool is_ft_collection = (std::find(ft_collection_list.begin(), ft_collection_list.end(), *file_name_it) != ft_collection_list.end());
+
+		bool is_ft_collection = (std::find_if(font_collection_files.begin(), font_collection_files.end(),
+		                                      [&font_file_it](const LLFontFileInfo& ffi) { return font_file_it->FileName == ffi.FileName; }) != font_collection_files.end());
+
 		// *HACK: Fallback fonts don't render, so we can use that to suppress
 		// creation of OpenGL textures for test apps. JC
 		BOOL is_fallback = !is_first_found || !mCreateGLTextures;
 		F32 extra_scale = (is_fallback)?fallback_scale:1.0;
 		F32 point_size_scale = extra_scale * point_size;
 		bool is_font_loaded = false;
-		for(string_vec_t::iterator font_paths_it = font_paths.begin();
-			font_paths_it != font_paths.end();
-			++font_paths_it)
+		for(string_vec_t::iterator font_search_path_it = font_search_paths.begin();
+			font_search_path_it != font_search_paths.end();
+			++font_search_path_it)
 		{
+			const std::string font_path = *font_search_path_it + font_file_it->FileName;
+
 			fontp = new LLFontGL;
-			S32 num_faces = is_ft_collection ? fontp->getNumFaces(*font_paths_it) : 1;
+			S32 num_faces = is_ft_collection ? fontp->getNumFaces(font_path) : 1;
 			for (S32 i = 0; i < num_faces; i++)
 			{
 				if (fontp == NULL)
 				{
 					fontp = new LLFontGL;
 				}
-				if (fontp->loadFace(*font_paths_it, point_size_scale,
-								 LLFontGL::sVertDPI, LLFontGL::sHorizDPI, true, is_fallback, i))
+				if (fontp->loadFace(font_path, point_size_scale,
+								 LLFontGL::sVertDPI, LLFontGL::sHorizDPI, is_fallback, i))
 				{
 					is_font_loaded = true;
 					if (is_first_found)
@@ -505,7 +525,8 @@ LLFontGL *LLFontRegistry::createFont(const LLFontDescriptor& desc)
 					}
 					else
 					{
-						fontlist.push_back(fontp->mFontFreetype);
+						result->mFontFreetype->addFallbackFont(fontp->mFontFreetype, font_file_it->CharFunctor);
+
 						delete fontp;
 						fontp = NULL;
 					}
@@ -520,17 +541,12 @@ LLFontGL *LLFontRegistry::createFont(const LLFontDescriptor& desc)
 		}
 		if(!is_font_loaded)
 		{
-			LL_INFOS_ONCE("LLFontRegistry") << "Couldn't load font " << *file_name_it <<  LL_ENDL;
+			LL_INFOS_ONCE("LLFontRegistry") << "Couldn't load font " << font_file_it->FileName <<  LL_ENDL;
 			delete fontp;
 			fontp = NULL;
 		}
 	}
 
-	if (result && !fontlist.empty())
-	{
-		result->mFontFreetype->setFallbackFonts(fontlist);
-	}
-
 	if (result)
 	{
 		result->mFontDescriptor = desc;
@@ -712,11 +728,11 @@ void LLFontRegistry::dump()
 				<< " size=[" << desc.getSize() << "]"
 				<< " fileNames="
 				<< LL_ENDL;
-		for (string_vec_t::const_iterator file_it=desc.getFileNames().begin();
-			 file_it != desc.getFileNames().end();
+		for (font_file_info_vec_t::const_iterator file_it=desc.getFontFiles().begin();
+			 file_it != desc.getFontFiles().end();
 			 ++file_it)
 		{
-			LL_INFOS() << "  file: " << *file_it <<LL_ENDL;
+			LL_INFOS() << "  file: " << file_it->FileName << LL_ENDL;
 		}
 	}
 }
diff --git a/indra/llrender/llfontregistry.h b/indra/llrender/llfontregistry.h
index b1259ef4e7..b0ef72c5de 100644
--- a/indra/llrender/llfontregistry.h
+++ b/indra/llrender/llfontregistry.h
@@ -34,13 +34,32 @@ class LLFontGL;
 
 typedef std::vector<std::string> string_vec_t;
 
+struct LLFontFileInfo
+{
+	LLFontFileInfo(const std::string& file_name, const std::function<bool(llwchar)>& char_functor = nullptr)
+		: FileName(file_name)
+		, CharFunctor(char_functor)
+	{
+	}
+
+	LLFontFileInfo(const LLFontFileInfo& ffi)
+		: FileName(ffi.FileName)
+		, CharFunctor(ffi.CharFunctor)
+	{
+	}
+
+	std::string FileName;
+	std::function<bool(llwchar)> CharFunctor;
+};
+typedef std::vector<LLFontFileInfo> font_file_info_vec_t;
+
 class LLFontDescriptor
 {
 public:
 	LLFontDescriptor();
 	LLFontDescriptor(const std::string& name, const std::string& size, const U8 style);
-	LLFontDescriptor(const std::string& name, const std::string& size, const U8 style, const string_vec_t& file_names);
-	LLFontDescriptor(const std::string& name, const std::string& size, const U8 style, const string_vec_t& file_names, const string_vec_t& font_collections);
+	LLFontDescriptor(const std::string& name, const std::string& size, const U8 style, const font_file_info_vec_t& font_list);
+	LLFontDescriptor(const std::string& name, const std::string& size, const U8 style, const font_file_info_vec_t& font_list, const font_file_info_vec_t& font_collection_list);
 	LLFontDescriptor normalize() const;
 
 	bool operator<(const LLFontDescriptor& b) const;
@@ -51,19 +70,26 @@ public:
 	void setName(const std::string& name) { mName = name; }
 	const std::string& getSize() const { return mSize; }
 	void setSize(const std::string& size) { mSize = size; }
-	const std::vector<std::string>& getFileNames() const { return mFileNames; }
-	std::vector<std::string>& getFileNames() { return mFileNames; }
-	const std::vector<std::string>& getFontCollectionsList() const { return mFontCollectionsList; }
-	std::vector<std::string>& getFontCollectionsList() { return mFontCollectionsList; }
+
+	void addFontFile(const std::string& file_name, const std::string& char_functor = LLStringUtil::null);
+	const font_file_info_vec_t & getFontFiles() const { return mFontFiles; }
+	void setFontFiles(const font_file_info_vec_t& font_files) { mFontFiles = font_files; }
+	void addFontCollectionFile(const std::string& file_name, const std::string& char_functor = LLStringUtil::null);
+	const font_file_info_vec_t& getFontCollectionFiles() const { return mFontCollectionFiles; }
+	void setFontCollectionFiles(const font_file_info_vec_t& font_collection_files) { mFontCollectionFiles = font_collection_files; }
+
 	const U8 getStyle() const { return mStyle; }
 	void setStyle(U8 style) { mStyle = style; }
 
 private:
 	std::string mName;
 	std::string mSize;
-	string_vec_t mFileNames;
-	string_vec_t mFontCollectionsList;
+	font_file_info_vec_t mFontFiles;
+	font_file_info_vec_t mFontCollectionFiles;
 	U8 mStyle;
+
+	typedef std::map<std::string, std::function<bool(llwchar)>> char_functor_map_t;
+	static char_functor_map_t mCharFunctors;
 };
 
 class LLFontRegistry
diff --git a/indra/newview/CMakeLists.txt b/indra/newview/CMakeLists.txt
index b83d3afadd..f03dcb4066 100644
--- a/indra/newview/CMakeLists.txt
+++ b/indra/newview/CMakeLists.txt
@@ -21,6 +21,7 @@ include(EXPAT)
 include(FMODEX)
 include(GLOD)
 include(Hunspell)
+include(ICU4C)
 include(JsonCpp)
 include(LLAppearance)
 include(LLAudio)
@@ -2003,6 +2004,7 @@ target_link_libraries(${VIEWER_BINARY_NAME}
     ${NDOF_LIBRARY}
     ${NVAPI_LIBRARY}
     ${HUNSPELL_LIBRARY}
+    ${ICU4C_LIBRARY}
     ${viewer_LIBRARIES}
     ${BOOST_PROGRAM_OPTIONS_LIBRARY}
     ${BOOST_REGEX_LIBRARY}
diff --git a/indra/newview/skins/default/xui/en/fonts.xml b/indra/newview/skins/default/xui/en/fonts.xml
index 2d5263b78f..6df666a700 100644
--- a/indra/newview/skins/default/xui/en/fonts.xml
+++ b/indra/newview/skins/default/xui/en/fonts.xml
@@ -3,6 +3,7 @@
 
   <font name="default" comment="default font files (global fallbacks)">
     <file>DejaVuSans.ttf</file>
+    <file functor="is_emoji">Twemoji.ttf</file>
     <os name="Windows">
       <file>meiryo.TTC</file>
       <file>MSGOTHIC.TTC</file>
diff --git a/indra/win_crash_logger/CMakeLists.txt b/indra/win_crash_logger/CMakeLists.txt
index 4fba26ab2f..d1de20a6a0 100644
--- a/indra/win_crash_logger/CMakeLists.txt
+++ b/indra/win_crash_logger/CMakeLists.txt
@@ -3,6 +3,7 @@
 project(win_crash_logger)
 
 include(00-Common)
+include(ICU4C)
 include(LLCommon)
 include(LLCoreHttp)
 include(LLCrashLogger)
@@ -74,6 +75,7 @@ add_executable(windows-crash-logger WIN32 ${win_crash_logger_SOURCE_FILES})
 
 target_link_libraries(windows-crash-logger
     ${BREAKPAD_EXCEPTION_HANDLER_LIBRARIES}
+    ${ICU4C_LIBRARY}
     ${LLCRASHLOGGER_LIBRARIES}
     ${LLWINDOW_LIBRARIES}
     ${LLVFS_LIBRARIES}