Bump revision to 4, for SPIR-V 1.5.
diff --git a/include/spirv/unified1/spirv.core.grammar.json b/include/spirv/unified1/spirv.core.grammar.json
index 6efa7aa..18901cd 100644
--- a/include/spirv/unified1/spirv.core.grammar.json
+++ b/include/spirv/unified1/spirv.core.grammar.json
@@ -27,7 +27,7 @@
   "magic_number" : "0x07230203",
   "major_version" : 1,
   "minor_version" : 5,
-  "revision" : 3,
+  "revision" : 4,
   "instruction_printing_class" : [
     {
       "tag"     : "@exclude"
diff --git a/include/spirv/unified1/spirv.cs b/include/spirv/unified1/spirv.cs
index 04d5c67..0419c0f 100644
--- a/include/spirv/unified1/spirv.cs
+++ b/include/spirv/unified1/spirv.cs
@@ -49,7 +49,7 @@
     {
         public const uint MagicNumber = 0x07230203;
         public const uint Version = 0x00010500;
-        public const uint Revision = 3;
+        public const uint Revision = 4;
         public const uint OpCodeMask = 0xffff;
         public const uint WordCountShift = 16;
 
diff --git a/include/spirv/unified1/spirv.h b/include/spirv/unified1/spirv.h
index 5c9d6cd..4e36b3a 100644
--- a/include/spirv/unified1/spirv.h
+++ b/include/spirv/unified1/spirv.h
@@ -54,11 +54,11 @@
 typedef unsigned int SpvId;
 
 #define SPV_VERSION 0x10500
-#define SPV_REVISION 3
+#define SPV_REVISION 4
 
 static const unsigned int SpvMagicNumber = 0x07230203;
 static const unsigned int SpvVersion = 0x00010500;
-static const unsigned int SpvRevision = 3;
+static const unsigned int SpvRevision = 4;
 static const unsigned int SpvOpCodeMask = 0xffff;
 static const unsigned int SpvWordCountShift = 16;
 
diff --git a/include/spirv/unified1/spirv.hpp b/include/spirv/unified1/spirv.hpp
index 26b35bb..988545c 100644
--- a/include/spirv/unified1/spirv.hpp
+++ b/include/spirv/unified1/spirv.hpp
@@ -50,11 +50,11 @@
 typedef unsigned int Id;
 
 #define SPV_VERSION 0x10500
-#define SPV_REVISION 3
+#define SPV_REVISION 4
 
 static const unsigned int MagicNumber = 0x07230203;
 static const unsigned int Version = 0x00010500;
-static const unsigned int Revision = 3;
+static const unsigned int Revision = 4;
 static const unsigned int OpCodeMask = 0xffff;
 static const unsigned int WordCountShift = 16;
 
diff --git a/include/spirv/unified1/spirv.hpp11 b/include/spirv/unified1/spirv.hpp11
index f4ca331..1e7d12e 100644
--- a/include/spirv/unified1/spirv.hpp11
+++ b/include/spirv/unified1/spirv.hpp11
@@ -50,11 +50,11 @@
 typedef unsigned int Id;
 
 #define SPV_VERSION 0x10500
-#define SPV_REVISION 3
+#define SPV_REVISION 4
 
 static const unsigned int MagicNumber = 0x07230203;
 static const unsigned int Version = 0x00010500;
-static const unsigned int Revision = 3;
+static const unsigned int Revision = 4;
 static const unsigned int OpCodeMask = 0xffff;
 static const unsigned int WordCountShift = 16;
 
diff --git a/include/spirv/unified1/spirv.json b/include/spirv/unified1/spirv.json
index c20cc58..8353274 100644
--- a/include/spirv/unified1/spirv.json
+++ b/include/spirv/unified1/spirv.json
@@ -55,7 +55,7 @@
             ],
             "MagicNumber": 119734787,
             "Version": 66816,
-            "Revision": 3,
+            "Revision": 4,
             "OpCodeMask": 65535,
             "WordCountShift": 16
         },
diff --git a/include/spirv/unified1/spirv.lua b/include/spirv/unified1/spirv.lua
index a639113..d97af41 100644
--- a/include/spirv/unified1/spirv.lua
+++ b/include/spirv/unified1/spirv.lua
@@ -45,7 +45,7 @@
 spv = {
     MagicNumber = 0x07230203,
     Version = 0x00010500,
-    Revision = 3,
+    Revision = 4,
     OpCodeMask = 0xffff,
     WordCountShift = 16,
 
diff --git a/include/spirv/unified1/spirv.py b/include/spirv/unified1/spirv.py
index 9a13ad1..869b7f3 100644
--- a/include/spirv/unified1/spirv.py
+++ b/include/spirv/unified1/spirv.py
@@ -45,7 +45,7 @@
 spv = {
     'MagicNumber' : 0x07230203,
     'Version' : 0x00010500,
-    'Revision' : 3,
+    'Revision' : 4,
     'OpCodeMask' : 0xffff,
     'WordCountShift' : 16,
 
diff --git a/include/spirv/unified1/spv.d b/include/spirv/unified1/spv.d
index 8eb3570..714e77f 100644
--- a/include/spirv/unified1/spv.d
+++ b/include/spirv/unified1/spv.d
@@ -52,7 +52,7 @@
 
 enum uint MagicNumber = 0x07230203;
 enum uint Version = 0x00010500;
-enum uint Revision = 3;
+enum uint Revision = 4;
 enum uint OpCodeMask = 0xffff;
 enum uint WordCountShift = 16;
 
diff --git a/tools/buildHeaders/header.cpp b/tools/buildHeaders/header.cpp
index aad94f7..926905e 100644
--- a/tools/buildHeaders/header.cpp
+++ b/tools/buildHeaders/header.cpp
@@ -70,8 +70,8 @@
 
         static const int         DocMagicNumber = 0x07230203;
         static const int         DocVersion     = 0x00010500;
-        static const int         DocRevision    = 3;
-        #define DocRevisionString                "3"
+        static const int         DocRevision    = 4;
+        #define DocRevisionString                "4"
         static const std::string DocCopyright;
         static const std::string DocComment1;
         static const std::string DocComment2;