diff --git a/BUILD.bazel b/BUILD.bazel
index e8cf6a8..1115b7d 100644
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -49,6 +49,11 @@
     srcs = ["build_info.py"],
 )
 
+py_binary(
+    name = "gen_extension_headers",
+    srcs = ["gen_extension_headers.py"],
+)
+
 genrule(
     name = "gen_build_info_h",
     srcs = ["CHANGES.md", "build_info.h.tmpl"],
@@ -58,6 +63,14 @@
     tools = [":build_info"],
 )
 
+genrule(
+    name = "gen_extension_headers_h",
+    srcs = ["glslang/ExtensionHeaders", "gen_extension_headers.py"],
+    outs = ["glslang/glsl_intrinsic_header.h"],
+    cmd_bash = "$(location gen_extension_headers) -i  $(location glslang/ExtensionHeaders) -o $(location glslang/glsl_intrinsic_header.h)",
+    tools = [":gen_extension_headers"],
+)
+
 COMMON_COPTS = select({
     "@bazel_tools//src/conditions:windows": [""],
     "//conditions:default": [
@@ -206,6 +219,7 @@
     srcs = [
         "StandAlone/StandAlone.cpp",
         "StandAlone/Worklist.h",
+        ":glslang/glsl_intrinsic_header.h"
     ],
     copts = COMMON_COPTS,
     deps = [
diff --git a/BUILD.gn b/BUILD.gn
index a37e1d2..06d3c4b 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -69,6 +69,23 @@
   ]
 }
 
+action("glslang_extension_headers") {
+  script = "gen_extension_headers.py"
+
+  out_file = "${target_gen_dir}/include/glslang/glsl_intrinsic_header.h"
+
+  inputs = [
+    script
+  ]
+  outputs = [ out_file ]
+  args = [
+    "-i",
+    rebase_path("glslang/ExtensionHeaders", root_build_dir),
+    "-o",
+    rebase_path(out_file, root_build_dir),
+  ]
+}
+
 spirv_tools_dir = glslang_spirv_tools_dir
 if (!defined(glslang_angle)) {
   glslang_angle = false
@@ -302,6 +319,7 @@
     ":glslang_build_info",
     ":glslang_default_resource_limits_sources",
     ":glslang_sources",
+    ":glslang_extension_headers",
   ]
   public_configs = [ ":glslang_hlsl" ]
 
diff --git a/StandAlone/CMakeLists.txt b/StandAlone/CMakeLists.txt
index 91bec6c..4d5545c 100644
--- a/StandAlone/CMakeLists.txt
+++ b/StandAlone/CMakeLists.txt
@@ -31,6 +31,22 @@
 # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+find_host_package(PythonInterp 3 REQUIRED)
+
+set(GLSLANG_INTRINSIC_H          "${GLSLANG_GENERATED_INCLUDEDIR}/glslang/glsl_intrinsic_header.h")
+set(GLSLANG_INTRINSIC_PY         "${CMAKE_SOURCE_DIR}/gen_extension_headers.py")
+set(GLSLANG_INTRINSIC_HEADER_DIR "${CMAKE_SOURCE_DIR}/glslang/ExtensionHeaders")
+
+add_custom_command(
+    OUTPUT  ${GLSLANG_INTRINSIC_H}
+    COMMAND ${PYTHON_EXECUTABLE} "${GLSLANG_INTRINSIC_PY}"
+            "-i" ${GLSLANG_INTRINSIC_HEADER_DIR}
+            "-o" ${GLSLANG_INTRINSIC_H}
+    DEPENDS ${GLSLANG_INTRINSIC_PY}
+    COMMENT "Generating ${GLSLANG_INTRINSIC_H}")
+
+#add_custom_target(glslangValidator DEPENDS ${GLSLANG_INTRINSIC_H})
+
 add_library(glslang-default-resource-limits
             ${CMAKE_CURRENT_SOURCE_DIR}/ResourceLimits.cpp
             ${CMAKE_CURRENT_SOURCE_DIR}/resource_limits_c.cpp)
@@ -41,7 +57,7 @@
                            PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
                            PUBLIC $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}>)
 
-set(SOURCES StandAlone.cpp DirStackFileIncluder.h)
+set(SOURCES StandAlone.cpp DirStackFileIncluder.h  ${GLSLANG_INTRINSIC_H})
 
 add_executable(glslangValidator ${SOURCES})
 set_property(TARGET glslangValidator PROPERTY FOLDER tools)
@@ -108,4 +124,4 @@
                 ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
     endif()
     install(EXPORT glslang-default-resource-limitsTargets DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake)
-endif()
+endif()
\ No newline at end of file
diff --git a/StandAlone/StandAlone.cpp b/StandAlone/StandAlone.cpp
index e62f92f..23e510c 100644
--- a/StandAlone/StandAlone.cpp
+++ b/StandAlone/StandAlone.cpp
@@ -2,6 +2,7 @@
 // Copyright (C) 2002-2005  3Dlabs Inc. Ltd.
 // Copyright (C) 2013-2016 LunarG, Inc.
 // Copyright (C) 2016-2020 Google, Inc.
+// Modifications Copyright(C) 2021 Advanced Micro Devices, Inc.All rights reserved.
 //
 // All rights reserved.
 //
@@ -65,6 +66,8 @@
 // Build-time generated includes
 #include "glslang/build_info.h"
 
+#include "glslang/glsl_intrinsic_header.h"
+
 extern "C" {
     GLSLANG_EXPORT void ShOutputHtml();
 }
@@ -263,6 +266,7 @@
 
 // Track the user's #define and #undef from the command line.
 TPreamble UserPreamble;
+std::string PreambleString;
 
 //
 // Create the default name for saving a binary if -o is not provided.
@@ -1204,8 +1208,17 @@
                        "Use '-e <name>'.\n");
             shader->setSourceEntryPoint(sourceEntryPointName);
         }
+
+        std::string intrinsicString = getIntrinsic(compUnit.text, compUnit.count);
+
+        PreambleString = "";
         if (UserPreamble.isSet())
-            shader->setPreamble(UserPreamble.get());
+            PreambleString.append(UserPreamble.get());
+
+        if (!intrinsicString.empty())
+            PreambleString.append(intrinsicString);
+
+        shader->setPreamble(PreambleString.c_str());
         shader->addProcesses(Processes);
 
 #ifndef GLSLANG_WEB
diff --git a/gen_extension_headers.py b/gen_extension_headers.py
new file mode 100644
index 0000000..a787f9a
--- /dev/null
+++ b/gen_extension_headers.py
@@ -0,0 +1,98 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2020 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import glob
+import sys
+import os
+
+def generate_main(glsl_files, output_header_file):
+    # Write commit ID to output header file
+    with open(output_header_file, "w") as header_file:
+        # Copyright Notice
+        header_string =  '/***************************************************************************\n'
+        header_string += ' *\n'
+        header_string += ' * Copyright (c) 2015-2021 The Khronos Group Inc.\n'
+        header_string += ' * Copyright (c) 2015-2021 Valve Corporation\n'
+        header_string += ' * Copyright (c) 2015-2021 LunarG, Inc.\n'
+        header_string += ' * Copyright (c) 2015-2021 Google Inc.\n'
+        header_string += ' * Copyright (c) 2021 Advanced Micro Devices, Inc.All rights reserved.\n'
+        header_string += ' *\n'
+        header_string += ' ****************************************************************************/\n'
+        header_string += '#pragma once\n\n'
+        header_string += '#ifndef _INTRINSIC_EXTENSION_HEADER_H_\n'
+        header_string += '#define _INTRINSIC_EXTENSION_HEADER_H_\n\n'
+        header_file.write(header_string)
+
+        symbol_name_list = []
+
+        for i in glsl_files:
+            glsl_contents = open(i,"r").read()
+
+            filename = os.path.basename(i)
+            symbol_name = filename.split(".")[0]
+            symbol_name_list.append(symbol_name)
+            header_name = symbol_name + ".h"
+            header_str = 'std::string %s_GLSL = R"(\n%s\n)";\n' % (symbol_name, glsl_contents)
+            header_str += '\n'
+            header_file.write(header_str)
+
+        contents = ''
+        contents += '\n'
+        contents += 'std::string getIntrinsic(const char* const* shaders, int n) {\n'
+        contents += '\tstd::string shaderString = "";\n';
+
+        contents += '\tfor (int i = 0; i < n; i++) {\n'
+
+        for symbol_name in symbol_name_list:
+            contents += '\t\tif (strstr(shaders[i], "%s") != NULL) {\n'   % (symbol_name)
+            contents += '\t\t    shaderString.append(%s_GLSL);\n' % (symbol_name)
+            contents += '\t\t}\n'
+
+        contents += '\t}\n'
+        contents += '\treturn shaderString;\n';
+        contents += '}\n'
+
+        contents += '\n#endif\n'
+        header_file.write(contents)
+
+def main():
+    if len(sys.argv) < 2:
+        raise Exception("Invalid number of arguments")
+
+    i = 0
+    while i < len(sys.argv):
+        opt = sys.argv[i]
+        i = i + 1
+
+        if opt == "-i" or opt == "-o":
+            if i == len(sys.argv):
+                raise Exception("Expected path after {}".format(opt))
+            val = sys.argv[i]
+            i = i + 1
+            if (opt == "-i"):
+                input_dir = val
+            elif (opt == "-o"):
+                output_file = val
+            else:
+                raise Exception("Unknown flag {}".format(opt))
+
+    glsl_files = glob.glob(input_dir + '/*.glsl')
+
+    # Generate main header
+    generate_main(glsl_files, output_file)
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file
diff --git a/glslang/ExtensionHeaders/GL_EXT_shader_realtime_clock.glsl b/glslang/ExtensionHeaders/GL_EXT_shader_realtime_clock.glsl
new file mode 100644
index 0000000..f74df6f
--- /dev/null
+++ b/glslang/ExtensionHeaders/GL_EXT_shader_realtime_clock.glsl
@@ -0,0 +1,54 @@
+//
+// Copyright (C) 2002-2005  3Dlabs Inc. Ltd.
+// Copyright (C) 2013-2016 LunarG, Inc.
+// Copyright (C) 2016-2020 Google, Inc.
+// Modifications Copyright(C) 2021 Advanced Micro Devices, Inc.All rights reserved.
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+//
+//    Redistributions of source code must retain the above copyright
+//    notice, this list of conditions and the following disclaimer.
+//
+//    Redistributions in binary form must reproduce the above
+//    copyright notice, this list of conditions and the following
+//    disclaimer in the documentation and/or other materials provided
+//    with the distribution.
+//
+//    Neither the name of 3Dlabs Inc. Ltd. nor the names of its
+//    contributors may be used to endorse or promote products derived
+//    from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+// COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+// ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+//
+
+#extension GL_EXT_spirv_intrinsics : enable
+#extension GL_ARB_gpu_shader_int64 : enable
+
+uvec2 clockRealtime2x32EXT(void) {
+    spirv_instruction (extensions = ["SPV_KHR_shader_clock"], capabilities = [5055], id = 5056)
+    uvec2 clockRealtime2x32EXT_internal(uint scope);
+    
+    return clockRealtime2x32EXT_internal(1 /*Device scope*/);
+}
+
+uint64_t clockRealtimeEXT(void) {
+    spirv_instruction (extensions = ["SPV_KHR_shader_clock"], capabilities = [5055], id = 5056)
+    uint64_t clockRealtimeEXT_internal(uint scope);
+    
+    return clockRealtimeEXT_internal(1 /*Device scope*/);
+}
\ No newline at end of file
diff --git a/glslang/MachineIndependent/Initialize.cpp b/glslang/MachineIndependent/Initialize.cpp
index ee4e2ca..9f92529 100644
--- a/glslang/MachineIndependent/Initialize.cpp
+++ b/glslang/MachineIndependent/Initialize.cpp
@@ -3,7 +3,7 @@
 // Copyright (C) 2012-2016 LunarG, Inc.
 // Copyright (C) 2015-2020 Google, Inc.
 // Copyright (C) 2017 ARM Limited.
-// Modifications Copyright (C) 2020 Advanced Micro Devices, Inc. All rights reserved.
+// Modifications Copyright (C) 2020-2021 Advanced Micro Devices, Inc. All rights reserved.
 //
 // All rights reserved.
 //
@@ -4653,13 +4653,11 @@
             "\n");
     }
 
-    // GL_ARB_shader_clock & GL_EXT_shader_realtime_clock
+    // GL_ARB_shader_clock
     if (profile != EEsProfile && version >= 450) {
         commonBuiltins.append(
             "uvec2 clock2x32ARB();"
             "uint64_t clockARB();"
-            "uvec2 clockRealtime2x32EXT();"
-            "uint64_t clockRealtimeEXT();"
             "\n");
     }
 
@@ -8408,9 +8406,6 @@
         symbolTable.setFunctionExtensions("clockARB",     1, &E_GL_ARB_shader_clock);
         symbolTable.setFunctionExtensions("clock2x32ARB", 1, &E_GL_ARB_shader_clock);
 
-        symbolTable.setFunctionExtensions("clockRealtimeEXT",     1, &E_GL_EXT_shader_realtime_clock);
-        symbolTable.setFunctionExtensions("clockRealtime2x32EXT", 1, &E_GL_EXT_shader_realtime_clock);
-
         if (profile == EEsProfile && version < 320) {
             symbolTable.setVariableExtensions("gl_PrimitiveID",  Num_AEP_geometry_shader, AEP_geometry_shader);
             symbolTable.setVariableExtensions("gl_Layer",        Num_AEP_geometry_shader, AEP_geometry_shader);