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Refactor TLiveTraverser from the former reflection traverser, for future use in binding mapping.

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This PR factors out the code that knows how to walk just the live parts of the AST.
The traverser in reflect.cpp is renamed to TReflectionTraverser, and inherits from
TLiveTraverser, which will also be used by a future binding offset PR.

The code is now smart about the entry point name (no longer hardcoded to "main").

There is an option to traverse all code (live+dead), because a consumer of the
class may wish to use it for both purposes without wanting a whole separate
class hierarchy.
This commit is contained in:
steve-lunarg 2016-09-19 15:35:12 -06:00
parent 6fccb3cd75
commit 55717302ef
4 changed files with 150 additions and 67 deletions
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78
glslang/MachineIndependent/reflection.cpp
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@ -1,5 +1,5 @@
//
//Copyright (C) 2013 LunarG, Inc.
//Copyright (C) 2013-2016 LunarG, Inc.
//
//All rights reserved.
//
@ -35,6 +35,7 @@
#include "../Include/Common.h"
#include "reflection.h"
#include "LiveTraverser.h"
#include "localintermediate.h"
#include "gl_types.h"
@ -62,37 +63,26 @@
// there wasn't exactly one entry point.
//
namespace glslang {
//
// The traverser: mostly pass through, except
// - processing function-call nodes to push live functions onto the stack of functions to process
// - processing binary nodes to see if they are dereferences of an aggregates to track
// - processing symbol nodes to see if they are non-aggregate objects to track
// - processing selection nodes to trim semantically dead code
//
// This ignores semantically dead code by using TLiveTraverser.
//
// This is in the glslang namespace directly so it can be a friend of TReflection.
//
class TLiveTraverser : public TIntermTraverser {
class TReflectionTraverser : public TLiveTraverser {
public:
TLiveTraverser(const TIntermediate& i, TReflection& r) : intermediate(i), reflection(r) { }
TReflectionTraverser(const TIntermediate& i, TReflection& r) :
TLiveTraverser(i), reflection(r) { }
virtual bool visitAggregate(TVisit, TIntermAggregate* node);
virtual bool visitBinary(TVisit, TIntermBinary* node);
virtual void visitSymbol(TIntermSymbol* base);
virtual bool visitSelection(TVisit, TIntermSelection* node);
// 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 (reflection.nameToIndex.find(call->getName()) == reflection.nameToIndex.end()) {
reflection.nameToIndex[call->getName()] = -1;
pushFunction(call->getName());
}
}
// Add a simple reference to a uniform variable to the uniform database, no dereference involved.
// However, no dereference doesn't mean simple... it could be a complex aggregate.
@ -358,21 +348,6 @@ public:
return blockIndex;
}
//
// 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) {
functions.push_back(candidate);
break;
}
}
}
// Are we at a level in a dereference chain at which individual active uniform queries are made?
bool isReflectionGranularity(const TType& type)
@ -639,33 +614,21 @@ public:
return type.isArray() ? type.getOuterArraySize() : 1;
}
typedef std::list<TIntermAggregate*> TFunctionStack;
TFunctionStack functions;
const TIntermediate& intermediate;
TReflection& reflection;
std::set<const TIntermNode*> processedDerefs;
protected:
TLiveTraverser(TLiveTraverser&);
TLiveTraverser& operator=(TLiveTraverser&);
TReflectionTraverser(TReflectionTraverser&);
TReflectionTraverser& operator=(TReflectionTraverser&);
};
//
// Implement the traversal functions of interest.
//
// To catch which function calls are not dead, and hence which functions must be visited.
bool TLiveTraverser::visitAggregate(TVisit /* visit */, TIntermAggregate* node)
{
if (node->getOp() == EOpFunctionCall)
addFunctionCall(node);
return true; // traverse this subtree
}
// To catch dereferenced aggregates that must be reflected.
// This catches them at the highest level possible in the tree.
bool TLiveTraverser::visitBinary(TVisit /* visit */, TIntermBinary* node)
bool TReflectionTraverser::visitBinary(TVisit /* visit */, TIntermBinary* node)
{
switch (node->getOp()) {
case EOpIndexDirect:
@ -683,7 +646,7 @@ bool TLiveTraverser::visitBinary(TVisit /* visit */, TIntermBinary* node)
}
// To reflect non-dereferenced objects.
void TLiveTraverser::visitSymbol(TIntermSymbol* base)
void TReflectionTraverser::visitSymbol(TIntermSymbol* base)
{
if (base->getQualifier().storage == EvqUniform)
addUniform(*base);
@ -692,21 +655,6 @@ void TLiveTraverser::visitSymbol(TIntermSymbol* base)
addAttribute(*base);
}
// To prune semantically dead paths.
bool TLiveTraverser::visitSelection(TVisit /* visit */, TIntermSelection* node)
{
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
}
//
// Implement TReflection methods.
@ -720,7 +668,7 @@ bool TReflection::addStage(EShLanguage, const TIntermediate& intermediate)
if (intermediate.getNumEntryPoints() != 1 || intermediate.isRecursive())
return false;
TLiveTraverser it(intermediate, *this);
TReflectionTraverser it(intermediate, *this);
// put the entry point on functions to process
it.pushFunction("main(");