michael@0: //
michael@0: // Copyright (c) 2002-2010 The ANGLE Project Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: //
michael@0: 
michael@0: #include "compiler/intermediate.h"
michael@0: 
michael@0: class TAliveTraverser : public TIntermTraverser {
michael@0: public:
michael@0:     TAliveTraverser(TQualifier q) : TIntermTraverser(true, false, false, true), found(false), qualifier(q)
michael@0:     {
michael@0:     }
michael@0: 
michael@0: 	bool wasFound() { return found; }
michael@0: 
michael@0: protected:
michael@0:     bool found;
michael@0:     TQualifier qualifier;
michael@0: 
michael@0:     void visitSymbol(TIntermSymbol*);
michael@0:     bool visitSelection(Visit, TIntermSelection*);
michael@0: };
michael@0: 
michael@0: //
michael@0: // Report whether or not a variable of the given qualifier type
michael@0: // is guaranteed written.  Not always possible to determine if
michael@0: // it is written conditionally.
michael@0: //
michael@0: // ?? It does not do this well yet, this is just a place holder
michael@0: // that simply determines if it was reference at all, anywhere.
michael@0: //
michael@0: bool QualifierWritten(TIntermNode* node, TQualifier qualifier)
michael@0: {
michael@0:     TAliveTraverser it(qualifier);
michael@0: 
michael@0:     if (node)
michael@0:         node->traverse(&it);
michael@0: 
michael@0:     return it.wasFound();
michael@0: }
michael@0: 
michael@0: void TAliveTraverser::visitSymbol(TIntermSymbol* node)
michael@0: {
michael@0:     //
michael@0:     // If it's what we're looking for, record it.
michael@0:     //
michael@0:     if (node->getQualifier() == qualifier)
michael@0:         found = true;
michael@0: }
michael@0: 
michael@0: bool TAliveTraverser::visitSelection(Visit preVisit, TIntermSelection* node)
michael@0: {
michael@0:     if (wasFound())
michael@0:         return false;
michael@0: 
michael@0:     return true;
michael@0: }