chromium/third_party/glslang/src/glslang/MachineIndependent/limits.cpp

//
// Copyright (C) 2013 LunarG, Inc.
//
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//
// Do sub tree walks for
// 1) inductive loop bodies to see if the inductive variable is modified
// 2) array-index expressions to see if they are "constant-index-expression"
//
// These are per Appendix A of ES 2.0:
//
// "Within the body of the loop, the loop index is not statically assigned to nor is it used as the
// argument to a function out or inout parameter."
//
// "The following are constant-index-expressions:
//  - Constant expressions
//  - Loop indices as defined in section 4
//  - Expressions composed of both of the above"
//
// N.B.: assuming the last rule excludes function calls
//

#include "ParseHelper.h"

namespace glslang {

//
// The inductive loop-body traverser.
//
// Just look at things that might modify the loop index.
//

class TInductiveTraverser : public TIntermTraverser { … };

// check binary operations for those modifying the loop index
bool TInductiveTraverser::visitBinary(TVisit /* visit */, TIntermBinary* node)
{ … }

// check unary operations for those modifying the loop index
bool TInductiveTraverser::visitUnary(TVisit /* visit */, TIntermUnary* node)
{ … }

// check function calls for arguments modifying the loop index
bool TInductiveTraverser::visitAggregate(TVisit /* visit */, TIntermAggregate* node)
{ … }

//
// External function to call for loop check.
//
void TParseContext::inductiveLoopBodyCheck(TIntermNode* body, long long loopId, TSymbolTable& symbolTable)
{ … }

//
// The "constant-index-expression" tranverser.
//
// Just look at things that can form an index.
//

class TIndexTraverser : public TIntermTraverser { … };

// make sure symbols are inductive-loop indexes
void TIndexTraverser::visitSymbol(TIntermSymbol* symbol)
{ … }

// check for function calls, assuming they are bad; spec. doesn't really say
bool TIndexTraverser::visitAggregate(TVisit /* visit */, TIntermAggregate* node)
{ … }

//
// External function to call for loop check.
//
void TParseContext::constantIndexExpressionCheck(TIntermNode* index)
{ … }

} // end namespace glslang