chromium/third_party/angle/src/compiler/translator/tree_ops/RewriteAtomicCounters.cpp

//
// Copyright 2019 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// RewriteAtomicCounters: Emulate atomic counter buffers with storage buffers.
//

#include "compiler/translator/tree_ops/RewriteAtomicCounters.h"

#include "compiler/translator/Compiler.h"
#include "compiler/translator/ImmutableStringBuilder.h"
#include "compiler/translator/SymbolTable.h"
#include "compiler/translator/tree_util/IntermNode_util.h"
#include "compiler/translator/tree_util/IntermTraverse.h"
#include "compiler/translator/tree_util/ReplaceVariable.h"

namespace sh
{
namespace
{
constexpr ImmutableString kAtomicCountersVarName   = …;
constexpr ImmutableString kAtomicCountersBlockName = …;
constexpr ImmutableString kAtomicCounterFieldName  = …;

// DeclareAtomicCountersBuffer adds a storage buffer array that's used with atomic counters.
const TVariable *DeclareAtomicCountersBuffers(TIntermBlock *root, TSymbolTable *symbolTable)
{ … }

TIntermTyped *CreateUniformBufferOffset(const TIntermTyped *uniformBufferOffsets, int binding)
{ … }

TIntermBinary *CreateAtomicCounterRef(TIntermTyped *atomicCounterExpression,
                                      const TVariable *atomicCounters,
                                      const TIntermTyped *uniformBufferOffsets)
{ … }

// Traverser that:
//
// 1. Removes the |uniform atomic_uint| declarations and remembers the binding and offset.
// 2. Substitutes |atomicVar[n]| with |buffer[binding].counters[offset + n]|.
class RewriteAtomicCountersTraverser : public TIntermTraverser
{ … };

}  // anonymous namespace

bool RewriteAtomicCounters(TCompiler *compiler,
                           TIntermBlock *root,
                           TSymbolTable *symbolTable,
                           const TIntermTyped *acbBufferOffsets,
                           const TVariable **atomicCountersOut)
{ … }
}  // namespace sh