Add GL_EXT_frag_depth.

Test/100.frag

@@ -100,4 +100,14 @@ void foo236()
     dFdx(v[0]);
     dFdy(3.2);
     fwidth(f13);
+    gl_FragDepth = f13;    // ERROR
+    gl_FragDepthEXT = f13; // ERROR
 }
+
+#extension GL_EXT_frag_depth : enable
+
+void foo239()
+{
+    gl_FragDepth = f13;    // ERROR
+    gl_FragDepthEXT = f13;
+}
\ No newline at end of file

Test/baseResults/100.frag.out

@@ -45,7 +45,10 @@ ERROR: 0:80: 'sampler/image' : type requires declaration of default precision qu
 ERROR: 0:91: 'dFdx' : required extension not requested: GL_OES_standard_derivatives
 ERROR: 0:92: 'dFdy' : required extension not requested: GL_OES_standard_derivatives
 ERROR: 0:93: 'fwidth' : required extension not requested: GL_OES_standard_derivatives
-ERROR: 40 compilation errors.  No code generated.
+ERROR: 0:103: 'gl_FragDepth' : undeclared identifier 
+ERROR: 0:104: 'gl_FragDepthEXT' : required extension not requested: GL_EXT_frag_depth
+ERROR: 0:111: 'gl_FragDepth' : undeclared identifier 
+ERROR: 43 compilation errors.  No code generated.
 
 ERROR: node is still EOpNull!
 0:3  Sequence
@@ -166,6 +169,21 @@ ERROR: node is still EOpNull!
 0:101        0.000000
 0:102      fwidth (mediump float)
 0:102        'f13' (invariant mediump float)
+0:103      move second child to first child (mediump float)
+0:103        'gl_FragDepth' (mediump float)
+0:103        'f13' (invariant mediump float)
+0:104      move second child to first child (highp float)
+0:104        'gl_FragDepthEXT' (gl_FragDepth highp float)
+0:104        'f13' (invariant mediump float)
+0:109  Function Definition: foo239( (void)
+0:109    Function Parameters: 
+0:111    Sequence
+0:111      move second child to first child (mediump float)
+0:111        'gl_FragDepth' (mediump float)
+0:111        'f13' (invariant mediump float)
+0:112      move second child to first child (highp float)
+0:112        'gl_FragDepthEXT' (gl_FragDepth highp float)
+0:112        'f13' (invariant mediump float)
 0:?   Linker Objects
 0:?     'a' (3-element array of mediump int)
 0:?     'uint' (mediump int)

glslang/MachineIndependent/Initialize.cpp

@@ -1425,6 +1425,9 @@ void TBuiltIns::initialize(int version, EProfile profile)
                 "mediump vec2  gl_PointCoord;"   // needs qualifier fixed later
                 "highp   float gl_FragDepth;"    // needs qualifier fixed later
                 );
+        stageBuiltins[EShLangFragment].append(
+            "highp float gl_FragDepthEXT;"       // GL_EXT_frag_depth
+            );
     }
     stageBuiltins[EShLangFragment].append("\n");
 
@@ -2138,16 +2141,18 @@ void IdentifyBuiltIns(int version, EProfile profile, EShLanguage language, TSymb
         break;
 
     case EShLangFragment:
-        SpecialQualifier("gl_FrontFacing", EvqFace, symbolTable);
-        SpecialQualifier("gl_FragCoord",   EvqFragCoord, symbolTable);
-        SpecialQualifier("gl_PointCoord",  EvqPointCoord, symbolTable);
-        SpecialQualifier("gl_FragColor",   EvqFragColor, symbolTable);
-        SpecialQualifier("gl_FragDepth",   EvqFragDepth, symbolTable);
+        SpecialQualifier("gl_FrontFacing",  EvqFace, symbolTable);
+        SpecialQualifier("gl_FragCoord",    EvqFragCoord, symbolTable);
+        SpecialQualifier("gl_PointCoord",   EvqPointCoord, symbolTable);
+        SpecialQualifier("gl_FragColor",    EvqFragColor, symbolTable);
+        SpecialQualifier("gl_FragDepth",    EvqFragDepth, symbolTable);
+        SpecialQualifier("gl_FragDepthEXT", EvqFragDepth, symbolTable);
         if (version == 100) {
             symbolTable.setFunctionExtensions("dFdx",   1, &GL_OES_standard_derivatives);
             symbolTable.setFunctionExtensions("dFdy",   1, &GL_OES_standard_derivatives);
             symbolTable.setFunctionExtensions("fwidth", 1, &GL_OES_standard_derivatives);
         }
+        symbolTable.setVariableExtensions("gl_FragDepthEXT", 1, &GL_EXT_frag_depth);
         break;
 
     case EShLangCompute:

glslang/MachineIndependent/SymbolTable.h

@@ -574,6 +574,13 @@ public:
             table[level]->setFunctionExtensions(name, num, extensions);
     }
 
+    void setVariableExtensions(const char* name, int num, const char* const extensions[])
+    {
+        TSymbol* symbol = find(TString(name));
+        if (symbol)
+            symbol->setExtensions(num, extensions);
+    }
+
     int getMaxSymbolId() { return uniqueId; }
     void dump(TInfoSink &infoSink) const;
 	void copyTable(const TSymbolTable& copyOf);

glslang/MachineIndependent/Versions.cpp

@@ -151,6 +151,7 @@ void TParseContext::initializeExtensionBehavior()
 {
     extensionBehavior[GL_OES_texture_3D]               = EBhDisable;
     extensionBehavior[GL_OES_standard_derivatives]     = EBhDisable;
+    extensionBehavior[GL_EXT_frag_depth]               = EBhDisable;
 
     extensionBehavior[GL_ARB_texture_rectangle]        = EBhDisable;
     extensionBehavior[GL_3DL_array_objects]            = EBhDisable;
@@ -167,7 +168,8 @@ const char* TParseContext::getPreamble()
         return
             "#define GL_ES 1\n"
             "#define GL_OES_texture_3D 1\n"
-            "#define GL_OES_standard_derivatives 1\n";
+            "#define GL_OES_standard_derivatives 1\n"
+            "#define GL_EXT_frag_depth 1\n";
     } else {
         return
             "#define GL_FRAGMENT_PRECISION_HIGH 1\n"

glslang/MachineIndependent/Versions.h

@@ -74,6 +74,7 @@ typedef enum {
 //
 const char* const GL_OES_texture_3D               = "GL_OES_texture_3D";
 const char* const GL_OES_standard_derivatives     = "GL_OES_standard_derivatives";
+const char* const GL_EXT_frag_depth               = "GL_EXT_frag_depth";
 
 const char* const GL_ARB_texture_rectangle        = "GL_ARB_texture_rectangle";
 const char* const GL_3DL_array_objects            = "GL_3DL_array_objects";