VariablePacker.cpp

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Author : Stuart Morgan
Date : 2019-08-14 12:25:12
Hash : 9d737966
Message : Standardize copyright notices to project style For all "ANGLE Project" copyrights, standardize to the format specified by the style guide. Changes: - "Copyright (c)" and "Copyright(c)" changed to just "Copyright". - Removed the second half of date ranges ("Y1Y1-Y2Y2"->"Y1Y1"). - Fixed a small number of files that had no copyright date using the initial commit year from the version control history. - Fixed one instance of copyright being "The ANGLE Project" rather than "The ANGLE Project Authors" These changes are applied both to the copyright of source file, and where applicable to copyright statements that are generated by templates. BUG=angleproject:3811 Change-Id: I973dd65e4ef9deeba232d5be74c768256a0eb2e5 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1754397 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>
src/compiler/translator/VariablePacker.cpp
//
// Copyright 2002 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.
//
// Check whether variables fit within packing limits according to the packing rules from the GLSL ES
// 1.00.17 spec, Appendix A, section 7.

#include <algorithm>

#include "angle_gl.h"

#include "common/utilities.h"
#include "compiler/translator/VariablePacker.h"

namespace sh
{

namespace
{

// Expand the variable so that struct variables are split into their individual fields.
// Will not set the mappedName or staticUse fields on the expanded variables.
void ExpandVariable(const ShaderVariable &variable,
                    const std::string &name,
                    std::vector<ShaderVariable> *expanded);

void ExpandStructVariable(const ShaderVariable &variable,
                          const std::string &name,
                          std::vector<ShaderVariable> *expanded)
{
    ASSERT(variable.isStruct());

    const std::vector<ShaderVariable> &fields = variable.fields;

    for (size_t fieldIndex = 0; fieldIndex < fields.size(); fieldIndex++)
    {
        const ShaderVariable &field = fields[fieldIndex];
        ExpandVariable(field, name + "." + field.name, expanded);
    }
}

void ExpandStructArrayVariable(const ShaderVariable &variable,
                               unsigned int arrayNestingIndex,
                               const std::string &name,
                               std::vector<ShaderVariable> *expanded)
{
    // Nested arrays are processed starting from outermost (arrayNestingIndex 0u) and ending at the
    // innermost.
    const unsigned int currentArraySize = variable.getNestedArraySize(arrayNestingIndex);
    for (unsigned int arrayElement = 0u; arrayElement < currentArraySize; ++arrayElement)
    {
        const std::string elementName = name + ArrayString(arrayElement);
        if (arrayNestingIndex + 1u < variable.arraySizes.size())
        {
            ExpandStructArrayVariable(variable, arrayNestingIndex + 1u, elementName, expanded);
        }
        else
        {
            ExpandStructVariable(variable, elementName, expanded);
        }
    }
}

void ExpandVariable(const ShaderVariable &variable,
                    const std::string &name,
                    std::vector<ShaderVariable> *expanded)
{
    if (variable.isStruct())
    {
        if (variable.isArray())
        {
            ExpandStructArrayVariable(variable, 0u, name, expanded);
        }
        else
        {
            ExpandStructVariable(variable, name, expanded);
        }
    }
    else
    {
        ShaderVariable expandedVar = variable;
        expandedVar.name           = name;

        expanded->push_back(expandedVar);
    }
}

int GetVariablePackingRows(const ShaderVariable &variable)
{
    return GetTypePackingRows(variable.type) * variable.getArraySizeProduct();
}

class VariablePacker
{
  public:
    bool checkExpandedVariablesWithinPackingLimits(unsigned int maxVectors,
                                                   std::vector<sh::ShaderVariable> *variables);

  private:
    static const int kNumColumns      = 4;
    static const unsigned kColumnMask = (1 << kNumColumns) - 1;

    unsigned makeColumnFlags(int column, int numComponentsPerRow);
    void fillColumns(int topRow, int numRows, int column, int numComponentsPerRow);
    bool searchColumn(int column, int numRows, int *destRow, int *destSize);

    int topNonFullRow_;
    int bottomNonFullRow_;
    int maxRows_;
    std::vector<unsigned> rows_;
};

struct TVariableInfoComparer
{
    bool operator()(const sh::ShaderVariable &lhs, const sh::ShaderVariable &rhs) const
    {
        int lhsSortOrder = gl::VariableSortOrder(lhs.type);
        int rhsSortOrder = gl::VariableSortOrder(rhs.type);
        if (lhsSortOrder != rhsSortOrder)
        {
            return lhsSortOrder < rhsSortOrder;
        }
        // Sort by largest first.
        return lhs.getArraySizeProduct() > rhs.getArraySizeProduct();
    }
};

unsigned VariablePacker::makeColumnFlags(int column, int numComponentsPerRow)
{
    return ((kColumnMask << (kNumColumns - numComponentsPerRow)) & kColumnMask) >> column;
}

void VariablePacker::fillColumns(int topRow, int numRows, int column, int numComponentsPerRow)
{
    unsigned columnFlags = makeColumnFlags(column, numComponentsPerRow);
    for (int r = 0; r < numRows; ++r)
    {
        int row = topRow + r;
        ASSERT((rows_[row] & columnFlags) == 0);
        rows_[row] |= columnFlags;
    }
}

bool VariablePacker::searchColumn(int column, int numRows, int *destRow, int *destSize)
{
    ASSERT(destRow);

    for (; topNonFullRow_ < maxRows_ && rows_[topNonFullRow_] == kColumnMask; ++topNonFullRow_)
    {
    }

    for (; bottomNonFullRow_ >= 0 && rows_[bottomNonFullRow_] == kColumnMask; --bottomNonFullRow_)
    {
    }

    if (bottomNonFullRow_ - topNonFullRow_ + 1 < numRows)
    {
        return false;
    }

    unsigned columnFlags = makeColumnFlags(column, 1);
    int topGoodRow       = 0;
    int smallestGoodTop  = -1;
    int smallestGoodSize = maxRows_ + 1;
    int bottomRow        = bottomNonFullRow_ + 1;
    bool found           = false;
    for (int row = topNonFullRow_; row <= bottomRow; ++row)
    {
        bool rowEmpty = row < bottomRow ? ((rows_[row] & columnFlags) == 0) : false;
        if (rowEmpty)
        {
            if (!found)
            {
                topGoodRow = row;
                found      = true;
            }
        }
        else
        {
            if (found)
            {
                int size = row - topGoodRow;
                if (size >= numRows && size < smallestGoodSize)
                {
                    smallestGoodSize = size;
                    smallestGoodTop  = topGoodRow;
                }
            }
            found = false;
        }
    }
    if (smallestGoodTop < 0)
    {
        return false;
    }

    *destRow = smallestGoodTop;
    if (destSize)
    {
        *destSize = smallestGoodSize;
    }
    return true;
}

bool VariablePacker::checkExpandedVariablesWithinPackingLimits(
    unsigned int maxVectors,
    std::vector<sh::ShaderVariable> *variables)
{
    ASSERT(maxVectors > 0);
    maxRows_          = maxVectors;
    topNonFullRow_    = 0;
    bottomNonFullRow_ = maxRows_ - 1;

    // Check whether each variable fits in the available vectors.
    for (const sh::ShaderVariable &variable : *variables)
    {
        // Structs should have been expanded before reaching here.
        ASSERT(!variable.isStruct());
        if (variable.getArraySizeProduct() > maxVectors / GetTypePackingRows(variable.type))
        {
            return false;
        }
    }

    // As per GLSL 1.017 Appendix A, Section 7 variables are packed in specific
    // order by type, then by size of array, largest first.
    std::sort(variables->begin(), variables->end(), TVariableInfoComparer());
    rows_.clear();
    rows_.resize(maxVectors, 0);

    // Packs the 4 column variables.
    size_t ii = 0;
    for (; ii < variables->size(); ++ii)
    {
        const sh::ShaderVariable &variable = (*variables)[ii];
        if (GetTypePackingComponentsPerRow(variable.type) != 4)
        {
            break;
        }
        topNonFullRow_ += GetVariablePackingRows(variable);
    }

    if (topNonFullRow_ > maxRows_)
    {
        return false;
    }

    // Packs the 3 column variables.
    int num3ColumnRows = 0;
    for (; ii < variables->size(); ++ii)
    {
        const sh::ShaderVariable &variable = (*variables)[ii];
        if (GetTypePackingComponentsPerRow(variable.type) != 3)
        {
            break;
        }
        num3ColumnRows += GetVariablePackingRows(variable);
    }

    if (topNonFullRow_ + num3ColumnRows > maxRows_)
    {
        return false;
    }

    fillColumns(topNonFullRow_, num3ColumnRows, 0, 3);

    // Packs the 2 column variables.
    int top2ColumnRow            = topNonFullRow_ + num3ColumnRows;
    int twoColumnRowsAvailable   = maxRows_ - top2ColumnRow;
    int rowsAvailableInColumns01 = twoColumnRowsAvailable;
    int rowsAvailableInColumns23 = twoColumnRowsAvailable;
    for (; ii < variables->size(); ++ii)
    {
        const sh::ShaderVariable &variable = (*variables)[ii];
        if (GetTypePackingComponentsPerRow(variable.type) != 2)
        {
            break;
        }
        int numRows = GetVariablePackingRows(variable);
        if (numRows <= rowsAvailableInColumns01)
        {
            rowsAvailableInColumns01 -= numRows;
        }
        else if (numRows <= rowsAvailableInColumns23)
        {
            rowsAvailableInColumns23 -= numRows;
        }
        else
        {
            return false;
        }
    }

    int numRowsUsedInColumns01 = twoColumnRowsAvailable - rowsAvailableInColumns01;
    int numRowsUsedInColumns23 = twoColumnRowsAvailable - rowsAvailableInColumns23;
    fillColumns(top2ColumnRow, numRowsUsedInColumns01, 0, 2);
    fillColumns(maxRows_ - numRowsUsedInColumns23, numRowsUsedInColumns23, 2, 2);

    // Packs the 1 column variables.
    for (; ii < variables->size(); ++ii)
    {
        const sh::ShaderVariable &variable = (*variables)[ii];
        ASSERT(1 == GetTypePackingComponentsPerRow(variable.type));
        int numRows        = GetVariablePackingRows(variable);
        int smallestColumn = -1;
        int smallestSize   = maxRows_ + 1;
        int topRow         = -1;
        for (int column = 0; column < kNumColumns; ++column)
        {
            int row  = 0;
            int size = 0;
            if (searchColumn(column, numRows, &row, &size))
            {
                if (size < smallestSize)
                {
                    smallestSize   = size;
                    smallestColumn = column;
                    topRow         = row;
                }
            }
        }

        if (smallestColumn < 0)
        {
            return false;
        }

        fillColumns(topRow, numRows, smallestColumn, 1);
    }

    ASSERT(variables->size() == ii);

    return true;
}

}  // anonymous namespace

int GetTypePackingComponentsPerRow(sh::GLenum type)
{
    switch (type)
    {
        case GL_FLOAT_MAT4:
        case GL_FLOAT_MAT2:
        case GL_FLOAT_MAT2x4:
        case GL_FLOAT_MAT3x4:
        case GL_FLOAT_MAT4x2:
        case GL_FLOAT_MAT4x3:
        case GL_FLOAT_VEC4:
        case GL_INT_VEC4:
        case GL_BOOL_VEC4:
        case GL_UNSIGNED_INT_VEC4:
            return 4;
        case GL_FLOAT_MAT3:
        case GL_FLOAT_MAT2x3:
        case GL_FLOAT_MAT3x2:
        case GL_FLOAT_VEC3:
        case GL_INT_VEC3:
        case GL_BOOL_VEC3:
        case GL_UNSIGNED_INT_VEC3:
            return 3;
        case GL_FLOAT_VEC2:
        case GL_INT_VEC2:
        case GL_BOOL_VEC2:
        case GL_UNSIGNED_INT_VEC2:
            return 2;
        default:
            ASSERT(gl::VariableComponentCount(type) == 1);
            return 1;
    }
}

int GetTypePackingRows(sh::GLenum type)
{
    switch (type)
    {
        case GL_FLOAT_MAT4:
        case GL_FLOAT_MAT2x4:
        case GL_FLOAT_MAT3x4:
        case GL_FLOAT_MAT4x3:
        case GL_FLOAT_MAT4x2:
            return 4;
        case GL_FLOAT_MAT3:
        case GL_FLOAT_MAT2x3:
        case GL_FLOAT_MAT3x2:
            return 3;
        case GL_FLOAT_MAT2:
            return 2;
        default:
            ASSERT(gl::VariableRowCount(type) == 1);
            return 1;
    }
}

template <typename T>
bool CheckVariablesInPackingLimits(unsigned int maxVectors, const std::vector<T> &variables)
{
    VariablePacker packer;
    std::vector<sh::ShaderVariable> expandedVariables;
    for (const ShaderVariable &variable : variables)
    {
        ExpandVariable(variable, variable.name, &expandedVariables);
    }
    return packer.checkExpandedVariablesWithinPackingLimits(maxVectors, &expandedVariables);
}

template bool CheckVariablesInPackingLimits<ShaderVariable>(
    unsigned int maxVectors,
    const std::vector<ShaderVariable> &variables);
template bool CheckVariablesInPackingLimits<Uniform>(unsigned int maxVectors,
                                                     const std::vector<Uniform> &variables);

}  // namespace sh
kc3-lang/angle/src/compiler/translator/VariablePacker.cpp

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kc3-lang/angle /src/compiler/translator/VariablePacker.cpp
