kc3-lang/angle/src/libANGLE/VaryingPacking.cpp

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• Author : Philip Lamoureux
  Date : 2020-05-29 11:23:44
  Hash : 9515707b
  Message : Move ShaderVariable utility function from utilities.cpp ShaderVars.cpp. Fixes an implied dependency cycle between translator and angle_common. This will also allow us to be more strict about declaring dependencies on GLSLANG headers. Tested by building and running angle_unit_tests on Linux. Bug: angleproject:4672 Change-Id: I331230d2cf179ccea140ee7a0d5a3c8768c58cb1 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2222682 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>

• src/libANGLE/VaryingPacking.cpp

• //
  // Copyright 2015 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.
  //
  // VaryingPacking:
  //   Class which describes a mapping from varyings to registers, according
  //   to the spec, or using custom packing algorithms. We also keep a register
  //   allocation list for the D3D renderer.
  //
  
  #include "libANGLE/VaryingPacking.h"
  
  #include "common/utilities.h"
  #include "libANGLE/Program.h"
  #include "libANGLE/Shader.h"
  
  namespace gl
  {
  
  namespace
  {
  
  // true if varying x has a higher priority in packing than y
  bool ComparePackedVarying(const PackedVarying &x, const PackedVarying &y)
  {
      // If the PackedVarying 'x' or 'y' to be compared is an array element, this clones an equivalent
      // non-array shader variable 'vx' or 'vy' for actual comparison instead.
      sh::ShaderVariable vx, vy;
      const sh::ShaderVariable *px, *py;
  
      px = &x.varying();
      py = &y.varying();
  
      if (x.isArrayElement())
      {
          vx = *px;
          vx.arraySizes.clear();
          px = &vx;
      }
  
      if (y.isArrayElement())
      {
          vy = *py;
          vy.arraySizes.clear();
          py = &vy;
      }
  
      return gl::CompareShaderVar(*px, *py);
  }
  
  }  // anonymous namespace
  
  // Implementation of VaryingInShaderRef
  VaryingInShaderRef::VaryingInShaderRef(ShaderType stageIn, const sh::ShaderVariable *varyingIn)
      : varying(varyingIn), stage(stageIn)
  {}
  
  VaryingInShaderRef::~VaryingInShaderRef() = default;
  
  VaryingInShaderRef::VaryingInShaderRef(VaryingInShaderRef &&other)
  {
      *this = std::move(other);
  }
  
  VaryingInShaderRef &VaryingInShaderRef::operator=(VaryingInShaderRef &&other)
  {
      std::swap(varying, other.varying);
      std::swap(stage, other.stage);
      std::swap(parentStructName, other.parentStructName);
      std::swap(parentStructMappedName, other.parentStructMappedName);
  
      return *this;
  }
  
  // Implementation of PackedVarying
  PackedVarying::PackedVarying(VaryingInShaderRef &&frontVaryingIn,
                               VaryingInShaderRef &&backVaryingIn,
                               sh::InterpolationType interpolationIn)
      : PackedVarying(std::move(frontVaryingIn), std::move(backVaryingIn), interpolationIn, 0)
  {}
  
  PackedVarying::PackedVarying(VaryingInShaderRef &&frontVaryingIn,
                               VaryingInShaderRef &&backVaryingIn,
                               sh::InterpolationType interpolationIn,
                               GLuint fieldIndexIn)
      : frontVarying(std::move(frontVaryingIn)),
        backVarying(std::move(backVaryingIn)),
        interpolation(interpolationIn),
        arrayIndex(GL_INVALID_INDEX),
        fieldIndex(fieldIndexIn)
  {}
  
  PackedVarying::~PackedVarying() = default;
  
  PackedVarying::PackedVarying(PackedVarying &&other)
      : frontVarying(other.frontVarying.stage, other.frontVarying.varying),
        backVarying(other.backVarying.stage, other.backVarying.varying)
  {
      *this = std::move(other);
  }
  
  PackedVarying &PackedVarying::operator=(PackedVarying &&other)
  {
      std::swap(frontVarying, other.frontVarying);
      std::swap(backVarying, other.backVarying);
      std::swap(interpolation, other.interpolation);
      std::swap(arrayIndex, other.arrayIndex);
      std::swap(fieldIndex, other.fieldIndex);
  
      return *this;
  }
  
  // Implementation of VaryingPacking
  VaryingPacking::VaryingPacking(GLuint maxVaryingVectors, PackMode packMode)
      : mRegisterMap(maxVaryingVectors), mPackMode(packMode)
  {}
  
  VaryingPacking::~VaryingPacking() = default;
  
  void VaryingPacking::reset()
  {
      clearRegisterMap();
      mRegisterList.clear();
      mPackedVaryings.clear();
  
      for (std::vector<std::string> inactiveVaryingMappedNames : mInactiveVaryingMappedNames)
      {
          inactiveVaryingMappedNames.clear();
      }
  }
  
  void VaryingPacking::clearRegisterMap()
  {
      std::fill(mRegisterMap.begin(), mRegisterMap.end(), Register());
  }
  
  // Packs varyings into generic varying registers, using the algorithm from
  // See [OpenGL ES Shading Language 1.00 rev. 17] appendix A section 7 page 111
  // Also [OpenGL ES Shading Language 3.00 rev. 4] Section 11 page 119
  // Returns false if unsuccessful.
  bool VaryingPacking::packVarying(const PackedVarying &packedVarying)
  {
      const sh::ShaderVariable &varying = packedVarying.varying();
  
      // "Non - square matrices of type matCxR consume the same space as a square matrix of type matN
      // where N is the greater of C and R."
      // Here we are a bit more conservative and allow packing non-square matrices more tightly.
      // Make sure we use transposed matrix types to count registers correctly.
      ASSERT(!varying.isStruct());
      GLenum transposedType       = gl::TransposeMatrixType(varying.type);
      unsigned int varyingRows    = gl::VariableRowCount(transposedType);
      unsigned int varyingColumns = gl::VariableColumnCount(transposedType);
  
      // Special pack mode for D3D9. Each varying takes a full register, no sharing.
      // TODO(jmadill): Implement more sophisticated component packing in D3D9.
      if (mPackMode == PackMode::ANGLE_NON_CONFORMANT_D3D9)
      {
          varyingColumns = 4;
      }
  
      // "Variables of type mat2 occupies 2 complete rows."
      // For non-WebGL contexts, we allow mat2 to occupy only two columns per row.
      else if (mPackMode == PackMode::WEBGL_STRICT && varying.type == GL_FLOAT_MAT2)
      {
          varyingColumns = 4;
      }
  
      // "Arrays of size N are assumed to take N times the size of the base type"
      // GLSL ES 3.10 section 4.3.6: Output variables cannot be arrays of arrays or arrays of
      // structures, so we may use getBasicTypeElementCount().
      const unsigned int elementCount = varying.getBasicTypeElementCount();
      varyingRows *= (packedVarying.isArrayElement() ? 1 : elementCount);
  
      unsigned int maxVaryingVectors = static_cast<unsigned int>(mRegisterMap.size());
  
      // Fail if we are packing a single over-large varying.
      if (varyingRows > maxVaryingVectors)
      {
          return false;
      }
  
      // "For 2, 3 and 4 component variables packing is started using the 1st column of the 1st row.
      // Variables are then allocated to successive rows, aligning them to the 1st column."
      if (varyingColumns >= 2 && varyingColumns <= 4)
      {
          for (unsigned int row = 0; row <= maxVaryingVectors - varyingRows; ++row)
          {
              if (isFree(row, 0, varyingRows, varyingColumns))
              {
                  insert(row, 0, packedVarying);
                  return true;
              }
          }
  
          // "For 2 component variables, when there are no spare rows, the strategy is switched to
          // using the highest numbered row and the lowest numbered column where the variable will
          // fit."
          if (varyingColumns == 2)
          {
              for (unsigned int r = maxVaryingVectors - varyingRows + 1; r-- >= 1;)
              {
                  if (isFree(r, 2, varyingRows, 2))
                  {
                      insert(r, 2, packedVarying);
                      return true;
                  }
              }
          }
  
          return false;
      }
  
      // "1 component variables have their own packing rule. They are packed in order of size, largest
      // first. Each variable is placed in the column that leaves the least amount of space in the
      // column and aligned to the lowest available rows within that column."
      ASSERT(varyingColumns == 1);
      unsigned int contiguousSpace[4]     = {0};
      unsigned int bestContiguousSpace[4] = {0};
      unsigned int totalSpace[4]          = {0};
  
      for (unsigned int row = 0; row < maxVaryingVectors; ++row)
      {
          for (unsigned int column = 0; column < 4; ++column)
          {
              if (mRegisterMap[row][column])
              {
                  contiguousSpace[column] = 0;
              }
              else
              {
                  contiguousSpace[column]++;
                  totalSpace[column]++;
  
                  if (contiguousSpace[column] > bestContiguousSpace[column])
                  {
                      bestContiguousSpace[column] = contiguousSpace[column];
                  }
              }
          }
      }
  
      unsigned int bestColumn = 0;
      for (unsigned int column = 1; column < 4; ++column)
      {
          if (bestContiguousSpace[column] >= varyingRows &&
              (bestContiguousSpace[bestColumn] < varyingRows ||
               totalSpace[column] < totalSpace[bestColumn]))
          {
              bestColumn = column;
          }
      }
  
      if (bestContiguousSpace[bestColumn] >= varyingRows)
      {
          for (unsigned int row = 0; row < maxVaryingVectors; row++)
          {
              if (isFree(row, bestColumn, varyingRows, 1))
              {
                  for (unsigned int arrayIndex = 0; arrayIndex < varyingRows; ++arrayIndex)
                  {
                      // If varyingRows > 1, it must be an array.
                      PackedVaryingRegister registerInfo;
                      registerInfo.packedVarying  = &packedVarying;
                      registerInfo.registerRow    = row + arrayIndex;
                      registerInfo.registerColumn = bestColumn;
                      registerInfo.varyingArrayIndex =
                          (packedVarying.isArrayElement() ? packedVarying.arrayIndex : arrayIndex);
                      registerInfo.varyingRowIndex = 0;
                      // Do not record register info for builtins.
                      // TODO(jmadill): Clean this up.
                      if (!varying.isBuiltIn())
                      {
                          mRegisterList.push_back(registerInfo);
                      }
                      mRegisterMap[row + arrayIndex][bestColumn] = true;
                  }
                  break;
              }
          }
          return true;
      }
  
      return false;
  }
  
  bool VaryingPacking::isFree(unsigned int registerRow,
                              unsigned int registerColumn,
                              unsigned int varyingRows,
                              unsigned int varyingColumns) const
  {
      for (unsigned int row = 0; row < varyingRows; ++row)
      {
          ASSERT(registerRow + row < mRegisterMap.size());
          for (unsigned int column = 0; column < varyingColumns; ++column)
          {
              ASSERT(registerColumn + column < 4);
              if (mRegisterMap[registerRow + row][registerColumn + column])
              {
                  return false;
              }
          }
      }
  
      return true;
  }
  
  void VaryingPacking::insert(unsigned int registerRow,
                              unsigned int registerColumn,
                              const PackedVarying &packedVarying)
  {
      unsigned int varyingRows    = 0;
      unsigned int varyingColumns = 0;
  
      const sh::ShaderVariable &varying = packedVarying.varying();
      ASSERT(!varying.isStruct());
      GLenum transposedType = gl::TransposeMatrixType(varying.type);
      varyingRows           = gl::VariableRowCount(transposedType);
      varyingColumns        = gl::VariableColumnCount(transposedType);
  
      PackedVaryingRegister registerInfo;
      registerInfo.packedVarying  = &packedVarying;
      registerInfo.registerColumn = registerColumn;
  
      // GLSL ES 3.10 section 4.3.6: Output variables cannot be arrays of arrays or arrays of
      // structures, so we may use getBasicTypeElementCount().
      const unsigned int arrayElementCount = varying.getBasicTypeElementCount();
      for (unsigned int arrayElement = 0; arrayElement < arrayElementCount; ++arrayElement)
      {
          if (packedVarying.isArrayElement() && arrayElement != packedVarying.arrayIndex)
          {
              continue;
          }
          for (unsigned int varyingRow = 0; varyingRow < varyingRows; ++varyingRow)
          {
              registerInfo.registerRow     = registerRow + (arrayElement * varyingRows) + varyingRow;
              registerInfo.varyingRowIndex = varyingRow;
              registerInfo.varyingArrayIndex = arrayElement;
              // Do not record register info for builtins.
              // TODO(jmadill): Clean this up.
              if (!varying.isBuiltIn())
              {
                  mRegisterList.push_back(registerInfo);
              }
  
              for (unsigned int columnIndex = 0; columnIndex < varyingColumns; ++columnIndex)
              {
                  mRegisterMap[registerInfo.registerRow][registerColumn + columnIndex] = true;
              }
          }
      }
  }
  
  void VaryingPacking::packUserVarying(const ProgramVaryingRef &ref,
                                       VaryingUniqueFullNames *uniqueFullNames)
  {
      const sh::ShaderVariable *input  = ref.frontShader;
      const sh::ShaderVariable *output = ref.backShader;
  
      // Will get the vertex shader interpolation by default.
      sh::InterpolationType interpolation = input ? input->interpolation : output->interpolation;
  
      VaryingInShaderRef frontVarying(ref.frontShaderStage, input);
      VaryingInShaderRef backVarying(ref.backShaderStage, output);
  
      mPackedVaryings.emplace_back(std::move(frontVarying), std::move(backVarying), interpolation);
      if (input)
      {
          (*uniqueFullNames)[ref.frontShaderStage].insert(
              mPackedVaryings.back().fullName(ref.frontShaderStage));
      }
      if (output)
      {
          (*uniqueFullNames)[ref.backShaderStage].insert(
              mPackedVaryings.back().fullName(ref.backShaderStage));
      }
  }
  
  void VaryingPacking::packUserVaryingField(const ProgramVaryingRef &ref,
                                            GLuint fieldIndex,
                                            VaryingUniqueFullNames *uniqueFullNames)
  {
      const sh::ShaderVariable *input  = ref.frontShader;
      const sh::ShaderVariable *output = ref.backShader;
  
      // Will get the vertex shader interpolation by default.
      sh::InterpolationType interpolation = input ? input->interpolation : output->interpolation;
  
      const sh::ShaderVariable *frontField = input ? &input->fields[fieldIndex] : nullptr;
      const sh::ShaderVariable *backField  = output ? &output->fields[fieldIndex] : nullptr;
  
      VaryingInShaderRef frontVarying(ref.frontShaderStage, frontField);
      VaryingInShaderRef backVarying(ref.backShaderStage, backField);
  
      if (input)
      {
          ASSERT(!frontField->isStruct() && !frontField->isArray());
          frontVarying.parentStructName       = input->name;
          frontVarying.parentStructMappedName = input->mappedName;
      }
      if (output)
      {
          ASSERT(!backField->isStruct() && !backField->isArray());
          backVarying.parentStructName       = output->name;
          backVarying.parentStructMappedName = output->mappedName;
      }
  
      mPackedVaryings.emplace_back(std::move(frontVarying), std::move(backVarying), interpolation,
                                   fieldIndex);
  
      if (input)
      {
          (*uniqueFullNames)[ref.frontShaderStage].insert(
              mPackedVaryings.back().fullName(ref.frontShaderStage));
      }
      if (output)
      {
          (*uniqueFullNames)[ref.backShaderStage].insert(
              mPackedVaryings.back().fullName(ref.backShaderStage));
      }
  }
  
  void VaryingPacking::packUserVaryingTF(const ProgramVaryingRef &ref, size_t subscript)
  {
      const sh::ShaderVariable *input = ref.frontShader;
  
      VaryingInShaderRef frontVarying(ref.frontShaderStage, input);
      VaryingInShaderRef backVarying(ref.backShaderStage, nullptr);
  
      mPackedVaryings.emplace_back(std::move(frontVarying), std::move(backVarying),
                                   input->interpolation);
      mPackedVaryings.back().arrayIndex = static_cast<GLuint>(subscript);
  }
  
  void VaryingPacking::packUserVaryingFieldTF(const ProgramVaryingRef &ref,
                                              const sh::ShaderVariable &field,
                                              GLuint fieldIndex)
  {
      const sh::ShaderVariable *input = ref.frontShader;
  
      VaryingInShaderRef frontVarying(ref.frontShaderStage, &field);
      VaryingInShaderRef backVarying(ref.backShaderStage, nullptr);
  
      frontVarying.parentStructName       = input->name;
      frontVarying.parentStructMappedName = input->mappedName;
  
      mPackedVaryings.emplace_back(std::move(frontVarying), std::move(backVarying),
                                   input->interpolation, fieldIndex);
  }
  
  bool VaryingPacking::collectAndPackUserVaryings(gl::InfoLog &infoLog,
                                                  const ProgramMergedVaryings &mergedVaryings,
                                                  const std::vector<std::string> &tfVaryings,
                                                  const bool isSeparableProgram)
  {
      VaryingUniqueFullNames uniqueFullNames;
      mPackedVaryings.clear();
      clearRegisterMap();
  
      for (const ProgramVaryingRef &ref : mergedVaryings)
      {
          const sh::ShaderVariable *input  = ref.frontShader;
          const sh::ShaderVariable *output = ref.backShader;
  
          // Only pack statically used varyings that have a matched input or output, plus special
          // builtins. Note that we pack all statically used user-defined varyings even if they are
          // not active. GLES specs are a bit vague on whether it's allowed to only pack active
          // varyings, though GLES 3.1 spec section 11.1.2.1 says that "device-dependent
          // optimizations" may be used to make vertex shader outputs fit.
          if ((input && output && output->staticUse) ||
              (input && input->isBuiltIn() && input->active) ||
              (output && output->isBuiltIn() && output->active) ||
              (isSeparableProgram && ((input && input->active) || (output && output->active))))
          {
              const sh::ShaderVariable *varying = output ? output : input;
  
              // Don't count gl_Position. Also don't count gl_PointSize for D3D9.
              if (varying->name != "gl_Position" &&
                  !(varying->name == "gl_PointSize" &&
                    mPackMode == PackMode::ANGLE_NON_CONFORMANT_D3D9))
              {
                  if (varying->isStruct())
                  {
                      ASSERT(!(varying->isArray() && varying == input));
  
                      for (GLuint fieldIndex = 0; fieldIndex < varying->fields.size(); ++fieldIndex)
                      {
                          packUserVaryingField(ref, fieldIndex, &uniqueFullNames);
                      }
                      if (input)
                      {
                          uniqueFullNames[ref.frontShaderStage].insert(input->name);
                      }
                      if (output)
                      {
                          uniqueFullNames[ref.backShaderStage].insert(output->name);
                      }
                  }
                  else
                  {
                      packUserVarying(ref, &uniqueFullNames);
                  }
                  continue;
              }
          }
  
          // If the varying is not used in the input, we know it is inactive, unless it's a separable
          // program, in which case the input shader may not exist in this program.
          if (!input && !isSeparableProgram)
          {
              mInactiveVaryingMappedNames[ref.backShaderStage].push_back(output->mappedName);
              continue;
          }
  
          // Keep Transform FB varyings in the merged list always.
          for (const std::string &tfVarying : tfVaryings)
          {
              std::vector<unsigned int> subscripts;
              std::string baseName = ParseResourceName(tfVarying, &subscripts);
              size_t subscript     = GL_INVALID_INDEX;
              if (!subscripts.empty())
              {
                  subscript = subscripts.back();
              }
              // Already packed for fragment shader.
              if (uniqueFullNames[ref.frontShaderStage].count(tfVarying) > 0 ||
                  uniqueFullNames[ref.frontShaderStage].count(baseName) > 0)
              {
                  continue;
              }
              if (input->isStruct())
              {
                  GLuint fieldIndex               = 0;
                  const sh::ShaderVariable *field = input->findField(tfVarying, &fieldIndex);
                  if (field != nullptr)
                  {
                      ASSERT(!field->isStruct() && !field->isArray());
  
                      packUserVaryingFieldTF(ref, *field, fieldIndex);
                      uniqueFullNames[ref.frontShaderStage].insert(tfVarying);
                  }
                  uniqueFullNames[ref.frontShaderStage].insert(input->name);
              }
              // Array as a whole and array element conflict has already been checked in
              // linkValidateTransformFeedback.
              else if (baseName == input->name)
              {
                  // only pack varyings that are not builtins.
                  if (tfVarying.compare(0, 3, "gl_") != 0)
                  {
                      packUserVaryingTF(ref, subscript);
                      uniqueFullNames[ref.frontShaderStage].insert(tfVarying);
                  }
                  // Continue to match next array element for 'input' if the current match is array
                  // element.
                  if (subscript == GL_INVALID_INDEX)
                  {
                      break;
                  }
              }
          }
  
          if (input && uniqueFullNames[ref.frontShaderStage].count(input->name) == 0)
          {
              mInactiveVaryingMappedNames[ref.frontShaderStage].push_back(input->mappedName);
          }
          if (output && uniqueFullNames[ref.backShaderStage].count(output->name) == 0)
          {
              mInactiveVaryingMappedNames[ref.backShaderStage].push_back(output->mappedName);
          }
      }
  
      std::sort(mPackedVaryings.begin(), mPackedVaryings.end(), ComparePackedVarying);
  
      return packUserVaryings(infoLog, mPackedVaryings);
  }
  
  // See comment on packVarying.
  bool VaryingPacking::packUserVaryings(gl::InfoLog &infoLog,
                                        const std::vector<PackedVarying> &packedVaryings)
  {
      // "Variables are packed into the registers one at a time so that they each occupy a contiguous
      // subrectangle. No splitting of variables is permitted."
      for (const PackedVarying &packedVarying : packedVaryings)
      {
          if (!packVarying(packedVarying))
          {
              ShaderType eitherStage = packedVarying.frontVarying.varying
                                           ? packedVarying.frontVarying.stage
                                           : packedVarying.backVarying.stage;
              infoLog << "Could not pack varying " << packedVarying.fullName(eitherStage);
  
              // TODO(jmadill): Implement more sophisticated component packing in D3D9.
              if (mPackMode == PackMode::ANGLE_NON_CONFORMANT_D3D9)
              {
                  infoLog << "Note: Additional non-conformant packing restrictions are enforced on "
                             "D3D9.";
              }
  
              return false;
          }
      }
  
      // Sort the packed register list
      std::sort(mRegisterList.begin(), mRegisterList.end());
  
      return true;
  }
  }  // namespace gl