chromium/third_party/angle/src/compiler/translator/tree_ops/spirv/RewriteR32fImages.cpp

//
// Copyright 2021 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.
//
// RewriteR32fImages: Change images qualified with r32f to use r32ui instead.
//

#include "compiler/translator/tree_ops/spirv/RewriteR32fImages.h"

#include "compiler/translator/Compiler.h"
#include "compiler/translator/ImmutableStringBuilder.h"
#include "compiler/translator/StaticType.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
{
bool IsR32fImage(const TType &type)
{ … }

ImageMap;

TIntermTyped *RewriteBuiltinFunctionCall(TCompiler *compiler,
                                         TSymbolTable *symbolTable,
                                         TIntermAggregate *node,
                                         const ImageMap &imageMap);

// Given an expression, this traverser calculates a new expression where builtin function calls to
// r32f images are replaced with ones to the mapped r32ui image.  In particular, this is run on the
// right node of EOpIndexIndirect binary nodes, so that the expression in the index gets a chance to
// go through this transformation.
class RewriteExpressionTraverser final : public TIntermTraverser
{ … };

// Rewrite the index of an EOpIndexIndirect expression as well as any arguments to the builtin
// function call.
TIntermTyped *RewriteExpression(TCompiler *compiler,
                                TSymbolTable *symbolTable,
                                TIntermTyped *expression,
                                const ImageMap &imageMap)
{ … }

// Given a builtin function call such as the following:
//
//     imageLoad(expression, ...);
//
// expression is in the form of:
//
// - image uniform
// - image uniform array indexed with EOpIndexDirect or EOpIndexIndirect.  Note that
//   RewriteArrayOfArrayOfOpaqueUniforms has already ensured that the image array is
//   single-dimension.
//
// The latter case (with EOpIndexIndirect) is not valid GLSL (up to GL_EXT_gpu_shader5), but if it
// were, the index itself could have contained an image builtin function call, so is recursively
// processed (in case supported in future).  Additionally, the other builtin function arguments may
// need processing too.
//
// This function creates a similar expression where the image uniforms (of type r32f) are replaced
// with those of r32ui type.
//
TIntermTyped *RewriteBuiltinFunctionCall(TCompiler *compiler,
                                         TSymbolTable *symbolTable,
                                         TIntermAggregate *node,
                                         const ImageMap &imageMap)
{ … }

// Traverser that:
//
// 1. Converts the layout(r32f, ...) ... image* name; declarations to use the r32ui format
// 2. Converts |imageLoad| and |imageStore| functions to use |uintBitsToFloat| and |floatBitsToUint|
//    respectively.
// 3. Converts |imageAtomicExchange| to use |floatBitsToUint| and |uintBitsToFloat|.
class RewriteR32fImagesTraverser : public TIntermTraverser
{ … };

}  // anonymous namespace

bool RewriteR32fImages(TCompiler *compiler, TIntermBlock *root, TSymbolTable *symbolTable)
{ … }
}  // namespace sh