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//
// Copyright 2020 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.
//
// ReplaceForShaderFramebufferFetch.h: Find any references to gl_LastFragData, and replace it with
// ANGLELastFragData.
//

#include "compiler/translator/tree_ops/vulkan/ReplaceForShaderFramebufferFetch.h"

#include "common/bitset_utils.h"
#include "compiler/translator/ImmutableStringBuilder.h"
#include "compiler/translator/SymbolTable.h"
#include "compiler/translator/tree_util/BuiltIn.h"
#include "compiler/translator/tree_util/IntermNode_util.h"
#include "compiler/translator/tree_util/IntermTraverse.h"
#include "compiler/translator/tree_util/RunAtTheBeginningOfShader.h"
#include "compiler/translator/tree_util/SpecializationConstant.h"
#include "compiler/translator/util.h"

namespace sh
{
namespace
{

using InputAttachmentIdxSet = angle::BitSet<32>;

constexpr unsigned int kInputAttachmentZero = 0;
constexpr unsigned int kArraySizeZero       = 0;

class InputAttachmentReferenceTraverser : public TIntermTraverser
{
  public:
    InputAttachmentReferenceTraverser(std::map<unsigned int, TIntermSymbol *> *declaredSymOut,
                                      unsigned int *maxInputAttachmentIndex,
                                      InputAttachmentIdxSet *constIndicesOut,
                                      bool *usedNonConstIndex)
        : TIntermTraverser(true, false, false),
          mDeclaredSym(declaredSymOut),
          mMaxInputAttachmentIndex(maxInputAttachmentIndex),
          mConstInputAttachmentIndices(constIndicesOut),
          mUsedNonConstIndex(usedNonConstIndex)
    {
        mDeclaredSym->clear();
        *mMaxInputAttachmentIndex = 0;
        mConstInputAttachmentIndices->reset();
        *mUsedNonConstIndex = false;
    }

    bool visitDeclaration(Visit visit, TIntermDeclaration *node) override;
    bool visitBinary(Visit visit, TIntermBinary *node) override;
    void visitSymbol(TIntermSymbol *node) override;

  private:
    void setInputAttachmentIndex(unsigned int index);

    std::map<unsigned int, TIntermSymbol *> *mDeclaredSym;
    unsigned int *mMaxInputAttachmentIndex;
    InputAttachmentIdxSet *mConstInputAttachmentIndices;
    bool *mUsedNonConstIndex;
};

class ReplaceVariableTraverser : public TIntermTraverser
{
  public:
    ReplaceVariableTraverser(
        const std::map<const TVariable *, const TIntermTyped *> &replacementMap)
        : TIntermTraverser(true, false, false), mReplacementMap(replacementMap)
    {}

    ReplaceVariableTraverser(const TVariable *toBeReplaced, const TIntermTyped *replacement)
        : TIntermTraverser(true, false, false), mReplacementMap({{toBeReplaced, replacement}})
    {}

    bool visitDeclaration(Visit visit, TIntermDeclaration *node) override;
    void visitSymbol(TIntermSymbol *node) override;

  private:
    const std::map<const TVariable *, const TIntermTyped *> mReplacementMap;
};

void InputAttachmentReferenceTraverser::setInputAttachmentIndex(unsigned int inputAttachmentIdx)
{
    ASSERT(inputAttachmentIdx < mConstInputAttachmentIndices->size());
    mConstInputAttachmentIndices->set(inputAttachmentIdx);
    *mMaxInputAttachmentIndex = std::max(*mMaxInputAttachmentIndex, inputAttachmentIdx);
}

bool InputAttachmentReferenceTraverser::visitDeclaration(Visit visit, TIntermDeclaration *node)
{
    const TIntermSequence &sequence = *node->getSequence();
    ASSERT(sequence.size() == 1);

    TIntermSymbol *symbol = sequence.front()->getAsSymbolNode();
    if (symbol == nullptr)
    {
        return true;
    }

    if (symbol->getType().getQualifier() == EvqFragmentInOut)
    {
        // The input attachment index is identical to the location qualifier.  If there's only one
        // output, GLSL is allowed to not specify the location qualifier, in which case it would
        // implicitly be at location 0.
        const unsigned int inputAttachmentIdx =
            std::max(0, symbol->getType().getLayoutQualifier().location);

        if (symbol->getType().isArray())
        {
            for (unsigned int index = 0; index < symbol->getType().getOutermostArraySize(); index++)
            {
                const unsigned int realInputAttachmentIdx = inputAttachmentIdx + index;
                setInputAttachmentIndex(realInputAttachmentIdx);
            }
        }
        else
        {
            setInputAttachmentIndex(inputAttachmentIdx);
        }

        mDeclaredSym->emplace(inputAttachmentIdx, symbol);
    }

    return true;
}

bool InputAttachmentReferenceTraverser::visitBinary(Visit visit, TIntermBinary *node)
{
    TOperator op = node->getOp();
    if (op != EOpIndexDirect && op != EOpIndexIndirect)
    {
        return true;
    }

    TIntermSymbol *left = node->getLeft()->getAsSymbolNode();
    if (!left)
    {
        return true;
    }
    else if (left->getName() != "gl_LastFragData")
    {
        return true;
    }

    const TConstantUnion *constIdx = node->getRight()->getConstantValue();
    if (!constIdx)
    {
        // If the shader code uses gl_LastFragData with a non-const index, the input attachment
        // variable should be created as the maximum number. So, the previous redeclared
        // variable will be reset.
        mDeclaredSym->clear();

        *mUsedNonConstIndex = true;
        mDeclaredSym->emplace(0, left);
        return true;
    }
    else
    {
        unsigned int idx = 0;
        switch (constIdx->getType())
        {
            case EbtInt:
                idx = constIdx->getIConst();
                break;
            case EbtUInt:
                idx = constIdx->getUConst();
                break;
            case EbtFloat:
                idx = static_cast<unsigned int>(constIdx->getFConst());
                break;
            case EbtBool:
                idx = constIdx->getBConst() ? 1 : 0;
                break;
            default:
                UNREACHABLE();
                break;
        }
        ASSERT(idx < mConstInputAttachmentIndices->size());
        mConstInputAttachmentIndices->set(idx);

        *mMaxInputAttachmentIndex = std::max(*mMaxInputAttachmentIndex, idx);
        mDeclaredSym->emplace(idx, left);
    }

    return true;
}

void InputAttachmentReferenceTraverser::visitSymbol(TIntermSymbol *symbol)
{
    if (symbol->getName() != "gl_LastFragColorARM")
    {
        return;
    }

    // Record usage of the gl_LastFragColorARM symbol in the AST so we know
    // how to replace it with ANGLELastFragData.
    const unsigned int inputAttachmentIdx =
        std::max(0, symbol->getType().getLayoutQualifier().location);
    setInputAttachmentIndex(inputAttachmentIdx);
    mDeclaredSym->emplace(inputAttachmentIdx, symbol);
}

bool ReplaceVariableTraverser::visitDeclaration(Visit visit, TIntermDeclaration *node)
{
    const TIntermSequence &sequence = *(node->getSequence());
    if (sequence.size() != 1)
    {
        return true;
    }

    TIntermTyped *nodeType = sequence.front()->getAsTyped();
    TIntermSymbol *symbol  = nodeType->getAsSymbolNode();
    if (symbol == nullptr)
    {
        return true;
    }

    const TVariable *variable = &symbol->variable();
    if (mReplacementMap.find(variable) != mReplacementMap.end())
    {
        TIntermSequence emptyReplacement;
        mMultiReplacements.emplace_back(getParentNode()->getAsBlock(), node,
                                        std::move(emptyReplacement));

        return true;
    }

    return true;
}

void ReplaceVariableTraverser::visitSymbol(TIntermSymbol *node)
{
    const TVariable *variable = &node->variable();
    if (mReplacementMap.find(variable) != mReplacementMap.end())
    {
        queueReplacement(mReplacementMap.at(variable)->deepCopy(), OriginalNode::IS_DROPPED);
    }
}

TBasicType GetBasicTypeForSubpassInput(TBasicType inputType)
{
    switch (inputType)
    {
        case EbtFloat:
            return EbtSubpassInput;
        case EbtInt:
            return EbtISubpassInput;
        case EbtUInt:
            return EbtUSubpassInput;
        default:
            UNREACHABLE();
            return EbtVoid;
    }
}

TBasicType GetBasicTypeForSubpassInput(const TIntermSymbol *originSymbol)
{
    if (originSymbol->getName().beginsWith("gl_LastFragData"))
    {
        return GetBasicTypeForSubpassInput(EbtFloat);
    }

    return GetBasicTypeForSubpassInput(originSymbol->getBasicType());
}

TIntermTyped *CreateSubpassLoadFuncCall(TSymbolTable *symbolTable,
                                        TBasicType inputType,
                                        TIntermSequence *arguments)
{
    return CreateBuiltInFunctionCallNode("subpassLoad", arguments, *symbolTable,
                                         kESSLInternalBackendBuiltIns);
}

class ReplaceSubpassInputUtils
{
  public:
    ReplaceSubpassInputUtils(TCompiler *compiler,
                             TSymbolTable *symbolTable,
                             TIntermBlock *root,
                             std::vector<ShaderVariable> *uniforms,
                             const bool usedNonConstIndex,
                             const InputAttachmentIdxSet &constIndices,
                             const std::map<unsigned int, TIntermSymbol *> &declaredVarVec)
        : mCompiler(compiler),
          mSymbolTable(symbolTable),
          mRoot(root),
          mUniforms(uniforms),
          mUsedNonConstIndex(usedNonConstIndex),
          mConstIndices(constIndices),
          mDeclaredVarVec(declaredVarVec)
    {
        mDeclareVariables.clear();
        mInputAttachmentArrayIdSeq = 0;
        mInputAttachmentVarList.clear();
        mDataLoadVarList.clear();
    }
    virtual ~ReplaceSubpassInputUtils() = default;

    virtual bool declareSubpassInputVariables() = 0;
    void declareVariablesForFetch(const unsigned int inputAttachmentIndex,
                                  const TVariable *dataLoadVar)
    {
        mDataLoadVarList[inputAttachmentIndex] = dataLoadVar;

        TIntermDeclaration *dataLoadVarDecl = new TIntermDeclaration;
        TIntermSymbol *dataLoadVarDeclarator =
            new TIntermSymbol(mDataLoadVarList[inputAttachmentIndex]);
        dataLoadVarDecl->appendDeclarator(dataLoadVarDeclarator);
        mDeclareVariables.push_back(dataLoadVarDecl);
    }

    virtual bool loadInputAttachmentData() = 0;

    void submitNewDeclaration()
    {
        for (unsigned int index = 0; index < mDeclareVariables.size(); index++)
        {
            mRoot->insertStatement(index, mDeclareVariables[index]);
        }

        mDeclareVariables.clear();
    }

  protected:
    bool declareSubpassInputVariableImpl(const TIntermSymbol *declaredVarSym,
                                         const unsigned int inputAttachmentIndex);
    void addInputAttachmentUniform(const unsigned int inputAttachmentIndex);

    TIntermNode *assignSubpassLoad(TIntermTyped *resultVar,
                                   TIntermTyped *inputAttachmentSymbol,
                                   const uint8_t targetVecSize);
    TIntermNode *loadInputAttachmentDataImpl(const size_t arraySize,
                                             const unsigned int inputAttachmentIndex,
                                             const TVariable *loadInputAttachmentDataVar);

    ImmutableString getInputAttachmentName(unsigned int index);

    TCompiler *mCompiler;
    TSymbolTable *mSymbolTable;
    TIntermBlock *mRoot;
    std::vector<ShaderVariable> *mUniforms;
    const bool mUsedNonConstIndex;
    const InputAttachmentIdxSet mConstIndices;
    const std::map<unsigned int, TIntermSymbol *> mDeclaredVarVec;

    TIntermSequence mDeclareVariables;
    unsigned int mInputAttachmentArrayIdSeq;
    std::map<unsigned int, TVariable *> mInputAttachmentVarList;
    std::map<unsigned int, const TVariable *> mDataLoadVarList;
};

ImmutableString ReplaceSubpassInputUtils::getInputAttachmentName(unsigned int index)
{
    std::stringstream nameStream = sh::InitializeStream<std::stringstream>();
    nameStream << sh::vk::kInputAttachmentName << index;
    return ImmutableString(nameStream.str());
}

bool ReplaceSubpassInputUtils::declareSubpassInputVariableImpl(
    const TIntermSymbol *declaredVarSym,
    const unsigned int inputAttachmentIndex)
{
    TBasicType subpassInputType = GetBasicTypeForSubpassInput(declaredVarSym);
    if (subpassInputType == EbtVoid)
    {
        return false;
    }

    TType *inputAttachmentType =
        new TType(subpassInputType, declaredVarSym->getPrecision(), EvqUniform, 1);
    TLayoutQualifier inputAttachmentQualifier     = inputAttachmentType->getLayoutQualifier();
    inputAttachmentQualifier.inputAttachmentIndex = inputAttachmentIndex;
    inputAttachmentType->setLayoutQualifier(inputAttachmentQualifier);

    mInputAttachmentVarList[inputAttachmentIndex] =
        new TVariable(mSymbolTable, getInputAttachmentName(inputAttachmentIndex),
                      inputAttachmentType, SymbolType::AngleInternal);
    TIntermSymbol *inputAttachmentDeclarator =
        new TIntermSymbol(mInputAttachmentVarList[inputAttachmentIndex]);

    TIntermDeclaration *inputAttachmentDecl = new TIntermDeclaration;
    inputAttachmentDecl->appendDeclarator(inputAttachmentDeclarator);

    mDeclareVariables.push_back(inputAttachmentDecl);

    return true;
}

void ReplaceSubpassInputUtils::addInputAttachmentUniform(const unsigned int inputAttachmentIndex)
{
    const TVariable *inputAttachmentVar = mInputAttachmentVarList[inputAttachmentIndex];

    ShaderVariable inputAttachmentUniform;
    inputAttachmentUniform.active    = true;
    inputAttachmentUniform.staticUse = true;
    inputAttachmentUniform.name.assign(inputAttachmentVar->name().data(),
                                       inputAttachmentVar->name().length());
    inputAttachmentUniform.mappedName.assign(inputAttachmentUniform.name);
    inputAttachmentUniform.isFragmentInOut = true;
    inputAttachmentUniform.location =
        inputAttachmentVar->getType().getLayoutQualifier().inputAttachmentIndex;
    mUniforms->push_back(inputAttachmentUniform);
}

TIntermNode *ReplaceSubpassInputUtils::assignSubpassLoad(TIntermTyped *resultVar,
                                                         TIntermTyped *inputAttachmentSymbol,
                                                         const uint8_t targetVecSize)
{
    // TODO: support interaction with multisampled framebuffers.  For example, the sample ID needs
    // to be provided to the built-in call here.  http://anglebug.com/6195

    TIntermSequence subpassArguments  = {inputAttachmentSymbol};
    TIntermTyped *subpassLoadFuncCall = CreateSubpassLoadFuncCall(
        mSymbolTable, inputAttachmentSymbol->getBasicType(), &subpassArguments);

    TIntermTyped *result = subpassLoadFuncCall;
    if (targetVecSize < 4)
    {
        TVector<int> fieldOffsets(targetVecSize);
        for (uint8_t i = 0; i < targetVecSize; i++)
        {
            fieldOffsets[i] = i;
        }

        result = new TIntermSwizzle(subpassLoadFuncCall, fieldOffsets);
    }

    return new TIntermBinary(EOpAssign, resultVar, result);
}

TIntermNode *ReplaceSubpassInputUtils::loadInputAttachmentDataImpl(
    const size_t arraySize,
    const unsigned int inputAttachmentIndex,
    const TVariable *loadInputAttachmentDataVar)
{
    TIntermNode *retExpression = nullptr;

    TIntermSymbol *loadInputAttachmentDataSymbol = new TIntermSymbol(loadInputAttachmentDataVar);

    TIntermTyped *left = nullptr;

    if (arraySize > 0)
    {
        TIntermBlock *blockNode = new TIntermBlock();

        for (uint32_t index = 0; index < arraySize; index++)
        {
            uint32_t attachmentIndex = inputAttachmentIndex + index;

            left = new TIntermBinary(EOpIndexDirect, loadInputAttachmentDataSymbol->deepCopy(),
                                     CreateIndexNode(index));

            blockNode->appendStatement(
                assignSubpassLoad(left, new TIntermSymbol(mInputAttachmentVarList[attachmentIndex]),
                                  left->getNominalSize()));
        }

        retExpression = blockNode;
    }
    else
    {
        if (loadInputAttachmentDataSymbol->isArray())
        {
            left = new TIntermBinary(EOpIndexDirect, loadInputAttachmentDataSymbol->deepCopy(),
                                     CreateIndexNode(inputAttachmentIndex));
        }
        else
        {
            left = loadInputAttachmentDataSymbol->deepCopy();
        }

        retExpression = assignSubpassLoad(
            left, new TIntermSymbol(mInputAttachmentVarList[inputAttachmentIndex]),
            left->getNominalSize());
    }

    return retExpression;
}

class ReplaceGlLastFragDataUtils : public ReplaceSubpassInputUtils
{
  public:
    ReplaceGlLastFragDataUtils(TCompiler *compiler,
                               TSymbolTable *symbolTable,
                               TIntermBlock *root,
                               std::vector<ShaderVariable> *uniforms,
                               const bool usedNonConstIndex,
                               const InputAttachmentIdxSet &constIndices,
                               const std::map<unsigned int, TIntermSymbol *> &declaredVarVec)
        : ReplaceSubpassInputUtils(compiler,
                                   symbolTable,
                                   root,
                                   uniforms,
                                   usedNonConstIndex,
                                   constIndices,
                                   declaredVarVec)
    {}

    bool declareSubpassInputVariables() override;
    bool loadInputAttachmentData() override;
};

bool ReplaceGlLastFragDataUtils::declareSubpassInputVariables()
{
    for (auto declaredVar : mDeclaredVarVec)
    {
        const unsigned int inputAttachmentIndex = declaredVar.first;
        if (mConstIndices.test(inputAttachmentIndex))
        {
            if (!declareSubpassInputVariableImpl(declaredVar.second, inputAttachmentIndex))
            {
                return false;
            }

            addInputAttachmentUniform(inputAttachmentIndex);
        }
    }

    return true;
}

bool ReplaceGlLastFragDataUtils::loadInputAttachmentData()
{
    TIntermNode *loadInputAttachmentBlock = new TIntermBlock();

    for (auto declaredVar : mDeclaredVarVec)
    {
        const unsigned int inputAttachmentIndex = declaredVar.first;
        if (mConstIndices.test(inputAttachmentIndex))
        {
            loadInputAttachmentBlock->getAsBlock()->appendStatement(loadInputAttachmentDataImpl(
                kArraySizeZero, inputAttachmentIndex, mDataLoadVarList[kArraySizeZero]));
        }
    }

    ASSERT(loadInputAttachmentBlock->getChildCount() > 0);
    if (!RunAtTheBeginningOfShader(mCompiler, mRoot, loadInputAttachmentBlock))
    {
        return false;
    }

    return true;
}

class ReplaceInOutUtils : public ReplaceSubpassInputUtils
{
  public:
    ReplaceInOutUtils(TCompiler *compiler,
                      TSymbolTable *symbolTable,
                      TIntermBlock *root,
                      std::vector<ShaderVariable> *uniforms,
                      const bool usedNonConstIndex,
                      const InputAttachmentIdxSet &constIndices,
                      const std::map<unsigned int, TIntermSymbol *> &declaredVarVec)
        : ReplaceSubpassInputUtils(compiler,
                                   symbolTable,
                                   root,
                                   uniforms,
                                   usedNonConstIndex,
                                   constIndices,
                                   declaredVarVec)
    {}

    bool declareSubpassInputVariables() override;
    bool loadInputAttachmentData() override;
};

bool ReplaceInOutUtils::declareSubpassInputVariables()
{
    for (auto declaredVar : mDeclaredVarVec)
    {
        const unsigned int inputAttachmentIndex = declaredVar.first;
        const unsigned int arraySize =
            (declaredVar.second->isArray() ? declaredVar.second->getOutermostArraySize() : 1);

        for (unsigned int arrayIndex = 0; arrayIndex < arraySize; arrayIndex++)
        {
            unsigned int attachmentIndex = inputAttachmentIndex + arrayIndex;

            if (!declareSubpassInputVariableImpl(declaredVar.second, attachmentIndex))
            {
                return false;
            }

            addInputAttachmentUniform(attachmentIndex);
        }
    }

    return true;
}

bool ReplaceInOutUtils::loadInputAttachmentData()
{
    TIntermBlock *loadInputAttachmentBlock = new TIntermBlock();

    for (auto declaredVar : mDeclaredVarVec)
    {
        const unsigned int inputAttachmentIndex = declaredVar.first;
        size_t arraySize =
            (declaredVar.second->isArray() ? declaredVar.second->getOutermostArraySize() : 0);
        loadInputAttachmentBlock->appendStatement(loadInputAttachmentDataImpl(
            arraySize, inputAttachmentIndex, mDataLoadVarList[inputAttachmentIndex]));
    }

    ASSERT(loadInputAttachmentBlock->getChildCount() > 0);
    if (!RunAtTheBeginningOfShader(mCompiler, mRoot, loadInputAttachmentBlock))
    {
        return false;
    }

    return true;
}

}  // anonymous namespace

[[nodiscard]] bool ReplaceLastFrag(TCompiler *compiler,
                                   TIntermBlock *root,
                                   TSymbolTable *symbolTable,
                                   std::vector<ShaderVariable> *uniforms,
                                   FramebufferFetchReplaceTarget target)
{
    // Common variables
    InputAttachmentIdxSet constIndices;
    std::map<unsigned int, TIntermSymbol *> glLastFragUsageMap;
    unsigned int maxInputAttachmentIndex = 0;
    bool usedNonConstIndex               = false;

    // Get informations for gl_LastFragData/gl_LastFragColorARM
    InputAttachmentReferenceTraverser informationTraverser(
        &glLastFragUsageMap, &maxInputAttachmentIndex, &constIndices, &usedNonConstIndex);
    root->traverse(&informationTraverser);
    if (constIndices.none() && !usedNonConstIndex)
    {
        // No references of gl_LastFragData/ColorARM
        return true;
    }

    ReplaceGlLastFragDataUtils replaceSubpassInputUtils(
        compiler, symbolTable, root, uniforms, usedNonConstIndex, constIndices, glLastFragUsageMap);
    if (!replaceSubpassInputUtils.declareSubpassInputVariables())
    {
        return false;
    }

    // Declare the variables which store the result of subpassLoad function
    const TVariable *glLastFragVar = nullptr;
    if (glLastFragUsageMap.size() > 0)
    {
        glLastFragVar = &glLastFragUsageMap.begin()->second->variable();
    }
    else
    {
        if (target == FramebufferFetchReplaceTarget::LastFragData)
        {
            glLastFragVar = static_cast<const TVariable *>(
                symbolTable->findBuiltIn(ImmutableString("gl_LastFragData"), 100));
        }
        else
        {
            glLastFragVar = static_cast<const TVariable *>(symbolTable->findBuiltIn(
                ImmutableString("gl_LastFragColorARM"), compiler->getShaderVersion()));
        }
    }

    if (!glLastFragVar)
    {
        return false;
    }

    ImmutableString loadVarName("ANGLELastFragData");
    TType *loadVarType = new TType(glLastFragVar->getType());
    loadVarType->setQualifier(EvqGlobal);

    TVariable *loadVar =
        new TVariable(symbolTable, loadVarName, loadVarType, SymbolType::AngleInternal);
    replaceSubpassInputUtils.declareVariablesForFetch(kInputAttachmentZero, loadVar);

    replaceSubpassInputUtils.submitNewDeclaration();

    // 3) Add the routine for reading InputAttachment data
    if (!replaceSubpassInputUtils.loadInputAttachmentData())
    {
        return false;
    }

    // 4) Replace gl_LastFragData/ColorARM with ANGLELastFragData
    ReplaceVariableTraverser replaceTraverser(glLastFragVar, new TIntermSymbol(loadVar));
    root->traverse(&replaceTraverser);
    if (!replaceTraverser.updateTree(compiler, root))
    {
        return false;
    }

    return true;
}

[[nodiscard]] bool ReplaceInOutVariables(TCompiler *compiler,
                                         TIntermBlock *root,
                                         TSymbolTable *symbolTable,
                                         std::vector<ShaderVariable> *uniforms)
{
    // Common variables
    InputAttachmentIdxSet constIndices;
    std::map<unsigned int, TIntermSymbol *> declaredInOutVarMap;
    unsigned int maxInputAttachmentIndex = 0;
    bool usedNonConstIndex               = false;

    // Get informations for inout variables
    InputAttachmentReferenceTraverser informationTraverser(
        &declaredInOutVarMap, &maxInputAttachmentIndex, &constIndices, &usedNonConstIndex);
    root->traverse(&informationTraverser);
    if (declaredInOutVarMap.size() == 0)
    {
        // No references of the variable decorated with a inout qualifier
        return true;
    }

    // Declare subpassInput uniform variables
    ReplaceInOutUtils replaceSubpassInputUtils(compiler, symbolTable, root, uniforms,
                                               usedNonConstIndex, constIndices,
                                               declaredInOutVarMap);
    if (!replaceSubpassInputUtils.declareSubpassInputVariables())
    {
        return false;
    }
    std::map<unsigned int, const TVariable *> toBeReplaced;
    std::map<unsigned int, const TVariable *> newOutVarArray;
    for (auto originInOutVarIter : declaredInOutVarMap)
    {
        const unsigned int inputAttachmentIndex = originInOutVarIter.first;
        const TIntermSymbol *originInOutVar     = originInOutVarIter.second;

        TType *newOutVarType = new TType(originInOutVar->getType());

        // We just want to use the original variable, but without an out qualifier instead of inout.
        ASSERT(originInOutVar->getName() != "gl_LastFragData");
        newOutVarType->setQualifier(EvqFragmentOut);

        TVariable *newOutVar = new TVariable(symbolTable, originInOutVar->getName(), newOutVarType,
                                             originInOutVar->variable().symbolType());
        newOutVarArray[inputAttachmentIndex] = newOutVar;
        replaceSubpassInputUtils.declareVariablesForFetch(inputAttachmentIndex,
                                                          newOutVarArray[inputAttachmentIndex]);

        toBeReplaced[inputAttachmentIndex] = &originInOutVar->variable();
    }

    replaceSubpassInputUtils.submitNewDeclaration();

    // 3) Add the routine for reading InputAttachment data
    if (!replaceSubpassInputUtils.loadInputAttachmentData())
    {
        return false;
    }

    std::map<const TVariable *, const TIntermTyped *> replacementMap;
    for (auto newOutVar = newOutVarArray.begin(); newOutVar != newOutVarArray.end(); newOutVar++)
    {
        const unsigned int index            = newOutVar->first;
        replacementMap[toBeReplaced[index]] = new TIntermSymbol(newOutVar->second);
    }

    // 4) Replace previous 'inout' variable with newly created 'inout' variable
    ReplaceVariableTraverser replaceTraverser(replacementMap);
    root->traverse(&replaceTraverser);
    return replaceTraverser.updateTree(compiler, root);
}

}  // namespace sh
kc3-lang/angle/src/compiler/translator/tree_ops/vulkan/ReplaceForShaderFramebufferFetch.cpp

Commit

src/compiler/translator/tree_ops/vulkan/ReplaceForShaderFramebufferFetch.cpp
