Basic infrastructure for redeclaring built-in variables (like gl_FragCoord) so…

Test/baseResults/specExamples.frag.out

@@ -8,17 +8,10 @@ ERROR: 0:71: 'Material' : only uniform interface blocks are supported
 ERROR: 0:79: 'Light' : only uniform interface blocks are supported 
 ERROR: 0:83: 'ColoredTexture' : only uniform interface blocks are supported 
 ERROR: 0:87: 'Color' : redefinition 
-ERROR: 0:89: 'gl_' : reserved built-in name 
 ERROR: 0:92: 'origin_upper_left' : unrecognized layout identifier 
-ERROR: 0:92: 'gl_' : reserved built-in name 
-ERROR: 0:92: 'gl_FragCoord' : redefinition 
 ERROR: 0:93: 'pixel_center_integer' : unrecognized layout identifier 
-ERROR: 0:93: 'gl_' : reserved built-in name 
-ERROR: 0:93: 'gl_FragCoord' : redefinition 
 ERROR: 0:94: 'origin_upper_left' : unrecognized layout identifier 
 ERROR: 0:94: 'pixel_center_integer' : unrecognized layout identifier 
-ERROR: 0:94: 'gl_' : reserved built-in name 
-ERROR: 0:94: 'gl_FragCoord' : redefinition 
 ERROR: 0:96: 'early_fragment_tests' : unrecognized layout identifier 
 ERROR: 0:99: 'local_size_x' : there is no such layout identifier taking an assigned value 
 ERROR: 0:99: 'local_size_y' : there is no such layout identifier taking an assigned value 
@@ -26,24 +19,11 @@ ERROR: 0:100: 'local_size_x' : there is no such layout identifier taking an assi
 ERROR: 0:102: 'color' : redefinition 
 ERROR: 0:103: 'index' : there is no such layout identifier taking an assigned value 
 ERROR: 0:106: 'depth_greater' : unrecognized layout identifier 
-ERROR: 0:106: 'gl_' : reserved built-in name 
-ERROR: 0:109: 'gl_' : reserved built-in name 
-ERROR: 0:109: 'gl_FragDepth' : redefinition 
 ERROR: 0:112: 'depth_any' : unrecognized layout identifier 
-ERROR: 0:112: 'gl_' : reserved built-in name 
-ERROR: 0:112: 'gl_FragDepth' : redefinition 
 ERROR: 0:115: 'depth_greater' : unrecognized layout identifier 
-ERROR: 0:115: 'gl_' : reserved built-in name 
-ERROR: 0:115: 'gl_FragDepth' : redefinition 
 ERROR: 0:118: 'depth_less' : unrecognized layout identifier 
-ERROR: 0:118: 'gl_' : reserved built-in name 
-ERROR: 0:118: 'gl_FragDepth' : redefinition 
 ERROR: 0:121: 'depth_unchanged' : unrecognized layout identifier 
-ERROR: 0:121: 'gl_' : reserved built-in name 
-ERROR: 0:121: 'gl_FragDepth' : redefinition 
 ERROR: 0:123: 'gl_' : reserved built-in name 
-ERROR: 0:124: 'gl_' : reserved built-in name 
-ERROR: 0:124: 'gl_Color' : redefinition 
 ERROR: 0:150: 'constructor' : constructing from a non-dereferenced array 
 ERROR: 0:152: '=' :  cannot convert from 'const 2-element array of 4-component vector of float' to '3-element array of 4-component vector of float'
 ERROR: 0:172: 'x' : undeclared identifier 
@@ -74,7 +54,7 @@ ERROR: 0:226: 'in' : only allowed at global scope
 ERROR: 0:227: 'in' : only allowed at global scope 
 ERROR: 0:228: 'in' : only allowed at global scope 
 ERROR: 0:232: 'out' : only allowed at global scope 
-ERROR: 76 compilation errors.  No code generated.
+ERROR: 56 compilation errors.  No code generated.
 
 ERROR: node is still EOpNull!
 0:5  Sequence
@@ -222,8 +202,8 @@ ERROR: node is still EOpNull!
 0:?     'temperature' (noperspective in float)
 0:?     'myColor' (flat in 3-component vector of float)
 0:?     'myTexCoord' (centroid noperspective in 2-component vector of float)
-0:?     'gl_FragCoord' (smooth in 4-component vector of float)
+0:?     'gl_FragCoord' (gl_FragCoord 4-component vector of float)
 0:?     'factor' (layout(location=3 ) out 4-component vector of float)
-0:?     'gl_FragDepth' (out float)
+0:?     'gl_FragDepth' (gl_FragDepth float)
 0:?     'gl_Color' (smooth in 4-component vector of float)
 

Test/baseResults/specExamples.vert.out

@@ -36,8 +36,6 @@ ERROR: 0:96: 'binding' : not supported
 ERROR: 0:97: 'binding' : not supported 
 ERROR: 0:106: '' : vertex input cannot be further qualified 
 ERROR: 0:106: 'gl_' : reserved built-in name 
-ERROR: 0:107: 'gl_' : reserved built-in name 
-ERROR: 0:107: 'gl_FrontColor' : redefinition 
 ERROR: 0:119: 'a' : redefinition 
 ERROR: 0:127: 'Block2' : nameless block contains a member that already has a name at global scope 
 ERROR: 0:132: 'shared' : not supported in this stage: vertex
@@ -56,7 +54,7 @@ ERROR: 0:191: '=' :  cannot convert from 'const 4-component vector of float' to
 ERROR: 0:192: 'constructor' : constructing from a non-dereferenced array 
 ERROR: 0:193: 'constructor' : constructing from a non-dereferenced array 
 ERROR: 0:194: 'constructor' : constructing from a non-dereferenced array 
-ERROR: 58 compilation errors.  No code generated.
+ERROR: 56 compilation errors.  No code generated.
 
 ERROR: node is still EOpNull!
 0:134  Function Definition: funcA(I21; (4-component vector of float)

glslang/MachineIndependent/ParseHelper.cpp

@@ -1180,13 +1180,13 @@ void TParseContext::globalCheck(TSourceLoc loc, bool global, const char* token)
 }
 
 //
-// For now, keep it simple:  if it starts "gl_", it's reserved, independent
-// of scope.  Except, if the symbol table is at the built-in push-level,
+// If it starts "gl_" or has double underscore, it's a reserved name.
+// Except, if the symbol table is at a built-in level,
 // which is when we are parsing built-ins.
 //
 bool TParseContext::reservedErrorCheck(TSourceLoc loc, const TString& identifier)
 {
-    if (!symbolTable.atBuiltInLevel()) {
+    if (! symbolTable.atBuiltInLevel()) {
         if (identifier.substr(0, 3) == TString("gl_")) {
             error(loc, "reserved built-in name", "gl_", "");
 
@@ -1805,23 +1805,81 @@ void TParseContext::nonInitConstCheck(TSourceLoc loc, TString& identifier, TPubl
 // Do semantic checking for a variable declaration that has no initializer,
 // and update the symbol table.
 //
-void TParseContext::nonInitCheck(TSourceLoc loc, TString& identifier, TPublicType& type)
+void TParseContext::nonInitCheck(TSourceLoc loc, TString& identifier, TPublicType& publicType)
 {
-    reservedErrorCheck(loc, identifier);
+    TType type(publicType);
+    bool newDeclaration;
+    TVariable* variable = redeclare(loc, identifier, type, newDeclaration);
+    if (! variable) {
+        reservedErrorCheck(loc, identifier);
+        variable = new TVariable(&identifier, type);
+        if (! symbolTable.insert(*variable))
+            error(loc, "redefinition", variable->getName().c_str(), "");
+        else
+            newDeclaration = true;
+    }
 
-    TVariable* variable = new TVariable(&identifier, TType(type));
-
-    if (! symbolTable.insert(*variable))
-        error(loc, "redefinition", variable->getName().c_str(), "");
-    else {
-        voidErrorCheck(loc, identifier, type);
+    if (newDeclaration) {
+        voidErrorCheck(loc, identifier, publicType);
 
         // see if it's a linker-level object to track
-        if (type.qualifier.isUniform() || type.qualifier.isPipeInput() || type.qualifier.isPipeOutput())
-            intermediate.addSymbolLinkageNode(linkage, *variable);
+        if (type.getQualifier().isUniform() || type.getQualifier().isPipeInput() || type.getQualifier().isPipeOutput())
+                intermediate.addSymbolLinkageNode(linkage, *variable);
     }
 }
 
+//
+// See if the identifier is a built-in symbol that can be redeclared,
+// and if so, copy of the symbol table's read-only built-in to the current
+// globol level, so it can be modified.
+//
+TVariable* TParseContext::redeclare(TSourceLoc loc, const TString& identifier, const TType& type, bool& newDeclaration)
+{
+    newDeclaration = false;
+
+    if (profile == EEsProfile || identifier.substr(0, 3) != TString("gl_") || symbolTable.atBuiltInLevel())
+        return 0;
+
+    // Potentially redeclaring a built-in variable...
+    
+    if (identifier == "gl_FragDepth"           && version >= 420 ||
+        identifier == "gl_PerVertex"           && version >= 410 ||
+        identifier == "gl_PerFragment"         && version >= 410 ||
+        identifier == "gl_FragCoord"           && version >= 150 ||
+        identifier == "gl_ClipDistance"        && version >= 130 ||
+        identifier == "gl_FrontColor"          && version >= 130 ||
+        identifier == "gl_BackColor"           && version >= 130 ||
+        identifier == "gl_FrontSecondaryColor" && version >= 130 ||
+        identifier == "gl_BackSecondaryColor"  && version >= 130 ||
+        identifier == "gl_SecondaryColor"      && version >= 130 ||
+        identifier == "gl_Color"               && version >= 130 && language == EShLangFragment ||
+        identifier == "gl_TexCoord") {
+
+        // Find the existing symbol, if any.
+        bool builtIn;
+        TSymbol* symbol = symbolTable.find(identifier, &builtIn);
+
+        // If the symbol was not found, this must be a version/profile/stage 
+        // that doesn't have it.
+        if (! symbol)
+            return 0;
+
+        TVariable* variable = symbol->getAsVariable();
+
+        // If it wasn't at a built-in level, then it's already been redeclared
+        if (! builtIn)
+            return variable;
+
+        // Otherwise, time to copy the symbol up to make a writable version
+        newDeclaration = true;
+        variable = symbolTable.copyUp(variable);
+        return variable;
+    }
+    
+    error(loc, "cannot redeclare this built-in variable", identifier.c_str(), "");
+    return 0;
+}
+
 void TParseContext::paramCheck(TSourceLoc loc, TStorageQualifier qualifier, TType* type)
 {
     switch (qualifier) {

glslang/MachineIndependent/ParseHelper.h

@@ -121,6 +121,7 @@ public:
     bool containsSampler(const TType& type);
     void nonInitConstCheck(TSourceLoc, TString& identifier, TPublicType& type);
     void nonInitCheck(TSourceLoc, TString& identifier, TPublicType& type);
+    TVariable* redeclare(TSourceLoc, const TString&, const TType&, bool& newDeclaration);
     void paramCheck(TSourceLoc, TStorageQualifier qualifier, TType* type);
     void nestedBlockCheck(TSourceLoc);
     void nestedStructCheck(TSourceLoc);
@@ -212,6 +213,7 @@ protected:
     TQualifier globalUniformDefaults;
     TQualifier globalInputDefaults;
     TQualifier globalOutputDefaults;
+    // TODO: desktop functionality: track use of gl_FragDepth before redeclaration
 };
 
 } // end namespace glslang