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

//
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#include "../Include/Common.h"
#include "reflection.h"
#include "LiveTraverser.h"
#include "localintermediate.h"

#include "gl_types.h"

//
// Grow the reflection database through a friend traverser class of TReflection and a
// collection of functions to do a liveness traversal that note what uniforms are used
// in semantically non-dead code.
//
// Can be used multiple times, once per stage, to grow a program reflection.
//
// High-level algorithm for one stage:
//
// 1. Put the entry point on the list of live functions.
//
// 2. Traverse any live function, while skipping if-tests with a compile-time constant
//    condition of false, and while adding any encountered function calls to the live
//    function list.
//
//    Repeat until the live function list is empty.
//
// 3. Add any encountered uniform variables and blocks to the reflection database.
//
// Can be attempted with a failed link, but will return false if recursion had been detected, or
// there wasn't exactly one entry point.
//

namespace glslang {

//
// The traverser: mostly pass through, except
//  - 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
//
// This ignores semantically dead code by using TLiveTraverser.
//
// This is in the glslang namespace directly so it can be a friend of TReflection.
//

class TReflectionTraverser : public TIntermTraverser { … };

//
// Implement the traversal functions of interest.
//

// To catch dereferenced aggregates that must be reflected.
// This catches them at the highest level possible in the tree.
bool TReflectionTraverser::visitBinary(TVisit /* visit */, TIntermBinary* node)
{ … }

// To reflect non-dereferenced objects.
void TReflectionTraverser::visitSymbol(TIntermSymbol* base)
{ … }

//
// Implement TObjectReflection methods.
//

TObjectReflection::TObjectReflection(const std::string &pName, const TType &pType, int pOffset, int pGLDefineType,
                                     int pSize, int pIndex)
    : … { … }

int TObjectReflection::getBinding() const
{ … }

void TObjectReflection::dump() const
{ … }

//
// Implement TReflection methods.
//

// Track any required attribute reflection, such as compute shader numthreads.
//
void TReflection::buildAttributeReflection(EShLanguage stage, const TIntermediate& intermediate)
{ … }

// build counter block index associations for buffers
void TReflection::buildCounterIndices(const TIntermediate& intermediate)
{ … }

// build Shader Stages mask for all uniforms
void TReflection::buildUniformStageMask(const TIntermediate& intermediate)
{ … }

// Merge live symbols from 'intermediate' into the existing reflection database.
//
// Returns false if the input is too malformed to do this.
bool TReflection::addStage(EShLanguage stage, const TIntermediate& intermediate)
{ … }

void TReflection::dump()
{ … }

} // end namespace glslang