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//
// Copyright (C) 2016 LunarG, Inc.
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
//
// Neither the name of 3Dlabs Inc. Ltd. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
// ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
#pragma once
#include "../Include/Common.h"
#include "reflection.h"
#include "localintermediate.h"
#include "gl_types.h"
#include <list>
#include <unordered_set>
namespace glslang {
//
// The traverser: mostly pass through, except
// - processing function-call nodes to push live functions onto the stack of functions to process
// - processing selection nodes to trim semantically dead code
//
// This is in the glslang namespace directly so it can be a friend of TReflection.
// This can be derived from to implement reflection database traversers or
// binding mappers: anything that wants to traverse the live subset of the tree.
//
class TLiveTraverser : public TIntermTraverser {
public:
TLiveTraverser(const TIntermediate& i, bool traverseAll = false,
bool preVisit = true, bool inVisit = false, bool postVisit = false) :
TIntermTraverser(preVisit, inVisit, postVisit),
intermediate(i), traverseAll(traverseAll)
{ }
//
// Given a function name, find its subroot in the tree, and push it onto the stack of
// functions left to process.
//
void pushFunction(const TString& name)
{
TIntermSequence& globals = intermediate.getTreeRoot()->getAsAggregate()->getSequence();
for (unsigned int f = 0; f < globals.size(); ++f) {
TIntermAggregate* candidate = globals[f]->getAsAggregate();
if (candidate && candidate->getOp() == EOpFunction && candidate->getName() == name) {
destinations.push_back(candidate);
break;
}
}
}
void pushGlobalReference(const TString& name)
{
TIntermSequence& globals = intermediate.getTreeRoot()->getAsAggregate()->getSequence();
for (unsigned int f = 0; f < globals.size(); ++f) {
TIntermAggregate* candidate = globals[f]->getAsAggregate();
if (candidate && candidate->getOp() == EOpSequence &&
candidate->getSequence().size() == 1 &&
candidate->getSequence()[0]->getAsBinaryNode()) {
TIntermBinary* binary = candidate->getSequence()[0]->getAsBinaryNode();
TIntermSymbol* symbol = binary->getLeft()->getAsSymbolNode();
if (symbol && symbol->getQualifier().storage == EvqGlobal &&
symbol->getName() == name) {
destinations.push_back(candidate);
break;
}
}
}
}
typedef std::list<TIntermAggregate*> TDestinationStack;
TDestinationStack destinations;
protected:
// To catch which function calls are not dead, and hence which functions must be visited.
virtual bool visitAggregate(TVisit, TIntermAggregate* node)
{
if (!traverseAll)
if (node->getOp() == EOpFunctionCall)
addFunctionCall(node);
return true; // traverse this subtree
}
// To prune semantically dead paths.
virtual bool visitSelection(TVisit /* visit */, TIntermSelection* node)
{
if (traverseAll)
return true; // traverse all code
TIntermConstantUnion* constant = node->getCondition()->getAsConstantUnion();
if (constant) {
// cull the path that is dead
if (constant->getConstArray()[0].getBConst() == true && node->getTrueBlock())
node->getTrueBlock()->traverse(this);
if (constant->getConstArray()[0].getBConst() == false && node->getFalseBlock())
node->getFalseBlock()->traverse(this);
return false; // don't traverse any more, we did it all above
} else
return true; // traverse the whole subtree
}
// Track live functions as well as uniforms, so that we don't visit dead functions
// and only visit each function once.
void addFunctionCall(TIntermAggregate* call)
{
// just use the map to ensure we process each function at most once
if (liveFunctions.find(call->getName()) == liveFunctions.end()) {
liveFunctions.insert(call->getName());
pushFunction(call->getName());
}
}
void addGlobalReference(const TString& name)
{
// just use the map to ensure we process each global at most once
if (liveGlobals.find(name) == liveGlobals.end()) {
liveGlobals.insert(name);
pushGlobalReference(name);
}
}
const TIntermediate& intermediate;
typedef std::unordered_set<TString> TLiveFunctions;
TLiveFunctions liveFunctions;
typedef std::unordered_set<TString> TLiveGlobals;
TLiveGlobals liveGlobals;
bool traverseAll;
private:
// prevent copy & copy construct
TLiveTraverser(TLiveTraverser&);
TLiveTraverser& operator=(TLiveTraverser&);
};
} // namespace glslang