Track if a non-preprocessor token has been seen and validate #extension with it.

src/compiler/preprocessor/DiagnosticsBase.cpp

@@ -123,6 +123,8 @@ std::string Diagnostics::message(ID id)
         return "unexpected token after conditional expression";
       case PP_UNRECOGNIZED_PRAGMA:
         return "unrecognized pragma";
+      case PP_NON_PP_TOKEN_BEFORE_EXTENSION:
+        return "extension directive must occur before any non-preprocessor tokens";
       // Warnings end.
       default:
         assert(false);

src/compiler/preprocessor/DiagnosticsBase.h

@@ -70,6 +70,7 @@ class Diagnostics
         PP_WARNING_BEGIN,
         PP_EOF_IN_DIRECTIVE,
         PP_UNRECOGNIZED_PRAGMA,
+        PP_NON_PP_TOKEN_BEFORE_EXTENSION,
         PP_WARNING_END
     };
 

src/compiler/preprocessor/DirectiveParser.cpp

@@ -211,6 +211,7 @@ DirectiveParser::DirectiveParser(Tokenizer *tokenizer,
                                  Diagnostics *diagnostics,
                                  DirectiveHandler *directiveHandler)
     : mPastFirstStatement(false),
+      mSeenNonPreprocessorToken(false),
       mTokenizer(tokenizer),
       mMacroSet(macroSet),
       mDiagnostics(diagnostics),
@@ -229,6 +230,10 @@ void DirectiveParser::lex(Token *token)
             parseDirective(token);
             mPastFirstStatement = true;
         }
+        else if (!isEOD(token))
+        {
+            mSeenNonPreprocessorToken = true;
+        }
 
         if (token->type == Token::LAST)
         {
@@ -715,6 +720,11 @@ void DirectiveParser::parseExtension(Token *token)
                              token->location, token->text);
         valid = false;
     }
+    if (valid && mSeenNonPreprocessorToken)
+    {
+        mDiagnostics->report(Diagnostics::PP_NON_PP_TOKEN_BEFORE_EXTENSION,
+                             token->location, token->text);
+    }
     if (valid)
         mDirectiveHandler->handleExtension(token->location, name, behavior);
 }

src/compiler/preprocessor/DirectiveParser.h

@@ -70,6 +70,8 @@ class DirectiveParser : public Lexer
         }
     };
     bool mPastFirstStatement;
+    bool mSeenNonPreprocessorToken; // Tracks if a non-preprocessor token has been seen yet.  Some macros, such as
+                                    // #extension must be declared before all shader code.
     std::vector<ConditionalBlock> mConditionalStack;
     Tokenizer *mTokenizer;
     MacroSet *mMacroSet;