Blenkernel: move DerivedMesh.c to c++

Required changes to make it compile with clang tidy:
* Use c++ includes like (e.g. climits instead limits.h).
* Insert type casts when casting from void* to something else.
* Replace NULL with nullptr.
* Insert casts from int to enum.
* Replace designed initializers (not supported in C++ yet).
* Use blender::Vector instead of BLI_array_staticdeclare (does not compile with C++).
* Replace typedef statements.

Ref T83357.

1 files changed, 2410 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/DerivedMesh.cc b/source/blender/blenkernel/intern/DerivedMesh.cc
new file mode 100644
index 00000000000..78d4ad6fe19
--- /dev/null
+++ b/source/blender/blenkernel/intern/DerivedMesh.cc
@@ -0,0 +1,2410 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2005 Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup bke
+ */
+
+#include <climits>
+#include <cstring>
+
+#include "MEM_guardedalloc.h"
+
+#include "DNA_cloth_types.h"
+#include "DNA_customdata_types.h"
+#include "DNA_key_types.h"
+#include "DNA_material_types.h"
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
+#include "DNA_object_types.h"
+#include "DNA_scene_types.h"
+
+#include "BLI_array.h"
+#include "BLI_bitmap.h"
+#include "BLI_blenlib.h"
+#include "BLI_float2.hh"
+#include "BLI_linklist.h"
+#include "BLI_math.h"
+#include "BLI_task.h"
+#include "BLI_utildefines.h"
+#include "BLI_vector.hh"
+
+#include "BKE_DerivedMesh.h"
+#include "BKE_bvhutils.h"
+#include "BKE_colorband.h"
+#include "BKE_deform.h"
+#include "BKE_editmesh.h"
+#include "BKE_key.h"
+#include "BKE_layer.h"
+#include "BKE_lib_id.h"
+#include "BKE_material.h"
+#include "BKE_mesh.h"
+#include "BKE_mesh_iterators.h"
+#include "BKE_mesh_mapping.h"
+#include "BKE_mesh_runtime.h"
+#include "BKE_mesh_tangent.h"
+#include "BKE_mesh_wrapper.h"
+#include "BKE_modifier.h"
+#include "BKE_multires.h"
+#include "BKE_object.h"
+#include "BKE_object_deform.h"
+#include "BKE_paint.h"
+
+#include "BLI_sys_types.h" /* for intptr_t support */
+
+#include "BKE_shrinkwrap.h"
+#include "DEG_depsgraph.h"
+#include "DEG_depsgraph_query.h"
+
+#include "CLG_log.h"
+
+#ifdef WITH_OPENSUBDIV
+#  include "DNA_userdef_types.h"
+#endif
+
+/* very slow! enable for testing only! */
+//#define USE_MODIFIER_VALIDATE
+
+#ifdef USE_MODIFIER_VALIDATE
+#  define ASSERT_IS_VALID_MESH(mesh) \
+    (BLI_assert((mesh == nullptr) || (BKE_mesh_is_valid(mesh) == true)))
+#else
+#  define ASSERT_IS_VALID_MESH(mesh)
+#endif
+
+static ThreadRWMutex loops_cache_lock = PTHREAD_RWLOCK_INITIALIZER;
+
+static void mesh_init_origspace(Mesh *mesh);
+static void editbmesh_calc_modifier_final_normals(Mesh *mesh_final,
+                                                  const CustomData_MeshMasks *final_datamask);
+
+/* -------------------------------------------------------------------- */
+
+static MVert *dm_getVertArray(DerivedMesh *dm)
+{
+  MVert *mvert = (MVert *)CustomData_get_layer(&dm->vertData, CD_MVERT);
+
+  if (!mvert) {
+    mvert = (MVert *)CustomData_add_layer(
+        &dm->vertData, CD_MVERT, CD_CALLOC, nullptr, dm->getNumVerts(dm));
+    CustomData_set_layer_flag(&dm->vertData, CD_MVERT, CD_FLAG_TEMPORARY);
+    dm->copyVertArray(dm, mvert);
+  }
+
+  return mvert;
+}
+
+static MEdge *dm_getEdgeArray(DerivedMesh *dm)
+{
+  MEdge *medge = (MEdge *)CustomData_get_layer(&dm->edgeData, CD_MEDGE);
+
+  if (!medge) {
+    medge = (MEdge *)CustomData_add_layer(
+        &dm->edgeData, CD_MEDGE, CD_CALLOC, nullptr, dm->getNumEdges(dm));
+    CustomData_set_layer_flag(&dm->edgeData, CD_MEDGE, CD_FLAG_TEMPORARY);
+    dm->copyEdgeArray(dm, medge);
+  }
+
+  return medge;
+}
+
+static MFace *dm_getTessFaceArray(DerivedMesh *dm)
+{
+  MFace *mface = (MFace *)CustomData_get_layer(&dm->faceData, CD_MFACE);
+
+  if (!mface) {
+    int numTessFaces = dm->getNumTessFaces(dm);
+
+    if (!numTessFaces) {
+      /* Do not add layer if there's no elements in it, this leads to issues later when
+       * this layer is needed with non-zero size, but currently CD stuff does not check
+       * for requested layer size on creation and just returns layer which was previously
+       * added (sergey) */
+      return nullptr;
+    }
+
+    mface = (MFace *)CustomData_add_layer(
+        &dm->faceData, CD_MFACE, CD_CALLOC, nullptr, numTessFaces);
+    CustomData_set_layer_flag(&dm->faceData, CD_MFACE, CD_FLAG_TEMPORARY);
+    dm->copyTessFaceArray(dm, mface);
+  }
+
+  return mface;
+}
+
+static MLoop *dm_getLoopArray(DerivedMesh *dm)
+{
+  MLoop *mloop = (MLoop *)CustomData_get_layer(&dm->loopData, CD_MLOOP);
+
+  if (!mloop) {
+    mloop = (MLoop *)CustomData_add_layer(
+        &dm->loopData, CD_MLOOP, CD_CALLOC, nullptr, dm->getNumLoops(dm));
+    CustomData_set_layer_flag(&dm->loopData, CD_MLOOP, CD_FLAG_TEMPORARY);
+    dm->copyLoopArray(dm, mloop);
+  }
+
+  return mloop;
+}
+
+static MPoly *dm_getPolyArray(DerivedMesh *dm)
+{
+  MPoly *mpoly = (MPoly *)CustomData_get_layer(&dm->polyData, CD_MPOLY);
+
+  if (!mpoly) {
+    mpoly = (MPoly *)CustomData_add_layer(
+        &dm->polyData, CD_MPOLY, CD_CALLOC, nullptr, dm->getNumPolys(dm));
+    CustomData_set_layer_flag(&dm->polyData, CD_MPOLY, CD_FLAG_TEMPORARY);
+    dm->copyPolyArray(dm, mpoly);
+  }
+
+  return mpoly;
+}
+
+static MVert *dm_dupVertArray(DerivedMesh *dm)
+{
+  MVert *tmp = (MVert *)MEM_malloc_arrayN(
+      dm->getNumVerts(dm), sizeof(*tmp), "dm_dupVertArray tmp");
+
+  if (tmp) {
+    dm->copyVertArray(dm, tmp);
+  }
+
+  return tmp;
+}
+
+static MEdge *dm_dupEdgeArray(DerivedMesh *dm)
+{
+  MEdge *tmp = (MEdge *)MEM_malloc_arrayN(
+      dm->getNumEdges(dm), sizeof(*tmp), "dm_dupEdgeArray tmp");
+
+  if (tmp) {
+    dm->copyEdgeArray(dm, tmp);
+  }
+
+  return tmp;
+}
+
+static MFace *dm_dupFaceArray(DerivedMesh *dm)
+{
+  MFace *tmp = (MFace *)MEM_malloc_arrayN(
+      dm->getNumTessFaces(dm), sizeof(*tmp), "dm_dupFaceArray tmp");
+
+  if (tmp) {
+    dm->copyTessFaceArray(dm, tmp);
+  }
+
+  return tmp;
+}
+
+static MLoop *dm_dupLoopArray(DerivedMesh *dm)
+{
+  MLoop *tmp = (MLoop *)MEM_malloc_arrayN(
+      dm->getNumLoops(dm), sizeof(*tmp), "dm_dupLoopArray tmp");
+
+  if (tmp) {
+    dm->copyLoopArray(dm, tmp);
+  }
+
+  return tmp;
+}
+
+static MPoly *dm_dupPolyArray(DerivedMesh *dm)
+{
+  MPoly *tmp = (MPoly *)MEM_malloc_arrayN(
+      dm->getNumPolys(dm), sizeof(*tmp), "dm_dupPolyArray tmp");
+
+  if (tmp) {
+    dm->copyPolyArray(dm, tmp);
+  }
+
+  return tmp;
+}
+
+static int dm_getNumLoopTri(DerivedMesh *dm)
+{
+  const int numlooptris = poly_to_tri_count(dm->getNumPolys(dm), dm->getNumLoops(dm));
+  BLI_assert(ELEM(dm->looptris.num, 0, numlooptris));
+  return numlooptris;
+}
+
+static const MLoopTri *dm_getLoopTriArray(DerivedMesh *dm)
+{
+  MLoopTri *looptri;
+
+  BLI_rw_mutex_lock(&loops_cache_lock, THREAD_LOCK_READ);
+  looptri = dm->looptris.array;
+  BLI_rw_mutex_unlock(&loops_cache_lock);
+
+  if (looptri != nullptr) {
+    BLI_assert(dm->getNumLoopTri(dm) == dm->looptris.num);
+  }
+  else {
+    BLI_rw_mutex_lock(&loops_cache_lock, THREAD_LOCK_WRITE);
+    /* We need to ensure array is still nullptr inside mutex-protected code,
+     * some other thread might have already recomputed those looptris. */
+    if (dm->looptris.array == nullptr) {
+      dm->recalcLoopTri(dm);
+    }
+    looptri = dm->looptris.array;
+    BLI_rw_mutex_unlock(&loops_cache_lock);
+  }
+  return looptri;
+}
+
+static CustomData *dm_getVertCData(DerivedMesh *dm)
+{
+  return &dm->vertData;
+}
+
+static CustomData *dm_getEdgeCData(DerivedMesh *dm)
+{
+  return &dm->edgeData;
+}
+
+static CustomData *dm_getTessFaceCData(DerivedMesh *dm)
+{
+  return &dm->faceData;
+}
+
+static CustomData *dm_getLoopCData(DerivedMesh *dm)
+{
+  return &dm->loopData;
+}
+
+static CustomData *dm_getPolyCData(DerivedMesh *dm)
+{
+  return &dm->polyData;
+}
+
+/**
+ * Utility function to initialize a DerivedMesh's function pointers to
+ * the default implementation (for those functions which have a default)
+ */
+void DM_init_funcs(DerivedMesh *dm)
+{
+  /* default function implementations */
+  dm->getVertArray = dm_getVertArray;
+  dm->getEdgeArray = dm_getEdgeArray;
+  dm->getTessFaceArray = dm_getTessFaceArray;
+  dm->getLoopArray = dm_getLoopArray;
+  dm->getPolyArray = dm_getPolyArray;
+  dm->dupVertArray = dm_dupVertArray;
+  dm->dupEdgeArray = dm_dupEdgeArray;
+  dm->dupTessFaceArray = dm_dupFaceArray;
+  dm->dupLoopArray = dm_dupLoopArray;
+  dm->dupPolyArray = dm_dupPolyArray;
+
+  dm->getLoopTriArray = dm_getLoopTriArray;
+
+  /* subtypes handle getting actual data */
+  dm->getNumLoopTri = dm_getNumLoopTri;
+
+  dm->getVertDataLayout = dm_getVertCData;
+  dm->getEdgeDataLayout = dm_getEdgeCData;
+  dm->getTessFaceDataLayout = dm_getTessFaceCData;
+  dm->getLoopDataLayout = dm_getLoopCData;
+  dm->getPolyDataLayout = dm_getPolyCData;
+
+  dm->getVertData = DM_get_vert_data;
+  dm->getEdgeData = DM_get_edge_data;
+  dm->getTessFaceData = DM_get_tessface_data;
+  dm->getPolyData = DM_get_poly_data;
+  dm->getVertDataArray = DM_get_vert_data_layer;
+  dm->getEdgeDataArray = DM_get_edge_data_layer;
+  dm->getTessFaceDataArray = DM_get_tessface_data_layer;
+  dm->getPolyDataArray = DM_get_poly_data_layer;
+  dm->getLoopDataArray = DM_get_loop_data_layer;
+}
+
+/**
+ * Utility function to initialize a DerivedMesh for the desired number
+ * of vertices, edges and faces (doesn't allocate memory for them, just
+ * sets up the custom data layers)
+ */
+void DM_init(DerivedMesh *dm,
+             DerivedMeshType type,
+             int numVerts,
+             int numEdges,
+             int numTessFaces,
+             int numLoops,
+             int numPolys)
+{
+  dm->type = type;
+  dm->numVertData = numVerts;
+  dm->numEdgeData = numEdges;
+  dm->numTessFaceData = numTessFaces;
+  dm->numLoopData = numLoops;
+  dm->numPolyData = numPolys;
+
+  DM_init_funcs(dm);
+
+  dm->needsFree = 1;
+  dm->dirty = (DMDirtyFlag)0;
+
+  /* don't use CustomData_reset(...); because we dont want to touch customdata */
+  copy_vn_i(dm->vertData.typemap, CD_NUMTYPES, -1);
+  copy_vn_i(dm->edgeData.typemap, CD_NUMTYPES, -1);
+  copy_vn_i(dm->faceData.typemap, CD_NUMTYPES, -1);
+  copy_vn_i(dm->loopData.typemap, CD_NUMTYPES, -1);
+  copy_vn_i(dm->polyData.typemap, CD_NUMTYPES, -1);
+}
+
+/**
+ * Utility function to initialize a DerivedMesh for the desired number
+ * of vertices, edges and faces, with a layer setup copied from source
+ */
+void DM_from_template_ex(DerivedMesh *dm,
+                         DerivedMesh *source,
+                         DerivedMeshType type,
+                         int numVerts,
+                         int numEdges,
+                         int numTessFaces,
+                         int numLoops,
+                         int numPolys,
+                         const CustomData_MeshMasks *mask)
+{
+  CustomData_copy(&source->vertData, &dm->vertData, mask->vmask, CD_CALLOC, numVerts);
+  CustomData_copy(&source->edgeData, &dm->edgeData, mask->emask, CD_CALLOC, numEdges);
+  CustomData_copy(&source->faceData, &dm->faceData, mask->fmask, CD_CALLOC, numTessFaces);
+  CustomData_copy(&source->loopData, &dm->loopData, mask->lmask, CD_CALLOC, numLoops);
+  CustomData_copy(&source->polyData, &dm->polyData, mask->pmask, CD_CALLOC, numPolys);
+
+  dm->cd_flag = source->cd_flag;
+
+  dm->type = type;
+  dm->numVertData = numVerts;
+  dm->numEdgeData = numEdges;
+  dm->numTessFaceData = numTessFaces;
+  dm->numLoopData = numLoops;
+  dm->numPolyData = numPolys;
+
+  DM_init_funcs(dm);
+
+  dm->needsFree = 1;
+  dm->dirty = (DMDirtyFlag)0;
+}
+void DM_from_template(DerivedMesh *dm,
+                      DerivedMesh *source,
+                      DerivedMeshType type,
+                      int numVerts,
+                      int numEdges,
+                      int numTessFaces,
+                      int numLoops,
+                      int numPolys)
+{
+  DM_from_template_ex(dm,
+                      source,
+                      type,
+                      numVerts,
+                      numEdges,
+                      numTessFaces,
+                      numLoops,
+                      numPolys,
+                      &CD_MASK_DERIVEDMESH);
+}
+
+bool DM_release(DerivedMesh *dm)
+{
+  if (dm->needsFree) {
+    CustomData_free(&dm->vertData, dm->numVertData);
+    CustomData_free(&dm->edgeData, dm->numEdgeData);
+    CustomData_free(&dm->faceData, dm->numTessFaceData);
+    CustomData_free(&dm->loopData, dm->numLoopData);
+    CustomData_free(&dm->polyData, dm->numPolyData);
+
+    MEM_SAFE_FREE(dm->looptris.array);
+    dm->looptris.num = 0;
+    dm->looptris.num_alloc = 0;
+
+    return true;
+  }
+
+  CustomData_free_temporary(&dm->vertData, dm->numVertData);
+  CustomData_free_temporary(&dm->edgeData, dm->numEdgeData);
+  CustomData_free_temporary(&dm->faceData, dm->numTessFaceData);
+  CustomData_free_temporary(&dm->loopData, dm->numLoopData);
+  CustomData_free_temporary(&dm->polyData, dm->numPolyData);
+
+  return false;
+}
+
+void DM_DupPolys(DerivedMesh *source, DerivedMesh *target)
+{
+  CustomData_free(&target->loopData, source->numLoopData);
+  CustomData_free(&target->polyData, source->numPolyData);
+
+  CustomData_copy(&source->loopData,
+                  &target->loopData,
+                  CD_MASK_DERIVEDMESH.lmask,
+                  CD_DUPLICATE,
+                  source->numLoopData);
+  CustomData_copy(&source->polyData,
+                  &target->polyData,
+                  CD_MASK_DERIVEDMESH.pmask,
+                  CD_DUPLICATE,
+                  source->numPolyData);
+
+  target->numLoopData = source->numLoopData;
+  target->numPolyData = source->numPolyData;
+
+  if (!CustomData_has_layer(&target->polyData, CD_MPOLY)) {
+    MPoly *mpoly;
+    MLoop *mloop;
+
+    mloop = source->dupLoopArray(source);
+    mpoly = source->dupPolyArray(source);
+    CustomData_add_layer(&target->loopData, CD_MLOOP, CD_ASSIGN, mloop, source->numLoopData);
+    CustomData_add_layer(&target->polyData, CD_MPOLY, CD_ASSIGN, mpoly, source->numPolyData);
+  }
+}
+
+void DM_ensure_normals(DerivedMesh *dm)
+{
+  if (dm->dirty & DM_DIRTY_NORMALS) {
+    dm->calcNormals(dm);
+  }
+  BLI_assert((dm->dirty & DM_DIRTY_NORMALS) == 0);
+}
+
+/**
+ * Ensure the array is large enough
+ *
+ * \note This function must always be thread-protected by caller.
+ * It should only be used by internal code.
+ */
+void DM_ensure_looptri_data(DerivedMesh *dm)
+{
+  const unsigned int totpoly = dm->numPolyData;
+  const unsigned int totloop = dm->numLoopData;
+  const int looptris_num = poly_to_tri_count(totpoly, totloop);
+
+  BLI_assert(dm->looptris.array_wip == nullptr);
+
+  SWAP(MLoopTri *, dm->looptris.array, dm->looptris.array_wip);
+
+  if ((looptris_num > dm->looptris.num_alloc) || (looptris_num < dm->looptris.num_alloc * 2) ||
+      (totpoly == 0)) {
+    MEM_SAFE_FREE(dm->looptris.array_wip);
+    dm->looptris.num_alloc = 0;
+    dm->looptris.num = 0;
+  }
+
+  if (totpoly) {
+    if (dm->looptris.array_wip == nullptr) {
+      dm->looptris.array_wip = (MLoopTri *)MEM_malloc_arrayN(
+          looptris_num, sizeof(*dm->looptris.array_wip), __func__);
+      dm->looptris.num_alloc = looptris_num;
+    }
+
+    dm->looptris.num = looptris_num;
+  }
+}
+
+/** Utility function to convert an (evaluated) Mesh to a shape key block. */
+/* Just a shallow wrapper around BKE_keyblock_convert_from_mesh,
+ * that ensures both evaluated mesh and original one has same number of vertices. */
+void BKE_mesh_runtime_eval_to_meshkey(Mesh *me_deformed, Mesh *me, KeyBlock *kb)
+{
+  const int totvert = me_deformed->totvert;
+
+  if (totvert == 0 || me->totvert == 0 || me->totvert != totvert) {
+    return;
+  }
+
+  BKE_keyblock_convert_from_mesh(me_deformed, me->key, kb);
+}
+
+/**
+ * set the CD_FLAG_NOCOPY flag in custom data layers where the mask is
+ * zero for the layer type, so only layer types specified by the mask
+ * will be copied
+ */
+void DM_set_only_copy(DerivedMesh *dm, const CustomData_MeshMasks *mask)
+{
+  CustomData_set_only_copy(&dm->vertData, mask->vmask);
+  CustomData_set_only_copy(&dm->edgeData, mask->emask);
+  CustomData_set_only_copy(&dm->faceData, mask->fmask);
+  /* this wasn't in 2.63 and is disabled for 2.64 because it gives problems with
+   * weight paint mode when there are modifiers applied, needs further investigation,
+   * see replies to r50969, Campbell */
+#if 0
+  CustomData_set_only_copy(&dm->loopData, mask->lmask);
+  CustomData_set_only_copy(&dm->polyData, mask->pmask);
+#endif
+}
+
+static void mesh_set_only_copy(Mesh *mesh, const CustomData_MeshMasks *mask)
+{
+  CustomData_set_only_copy(&mesh->vdata, mask->vmask);
+  CustomData_set_only_copy(&mesh->edata, mask->emask);
+  CustomData_set_only_copy(&mesh->fdata, mask->fmask);
+  /* this wasn't in 2.63 and is disabled for 2.64 because it gives problems with
+   * weight paint mode when there are modifiers applied, needs further investigation,
+   * see replies to r50969, Campbell */
+#if 0
+  CustomData_set_only_copy(&mesh->ldata, mask->lmask);
+  CustomData_set_only_copy(&mesh->pdata, mask->pmask);
+#endif
+}
+
+void DM_add_vert_layer(DerivedMesh *dm, int type, eCDAllocType alloctype, void *layer)
+{
+  CustomData_add_layer(&dm->vertData, type, alloctype, layer, dm->numVertData);
+}
+
+void DM_add_edge_layer(DerivedMesh *dm, int type, eCDAllocType alloctype, void *layer)
+{
+  CustomData_add_layer(&dm->edgeData, type, alloctype, layer, dm->numEdgeData);
+}
+
+void DM_add_tessface_layer(DerivedMesh *dm, int type, eCDAllocType alloctype, void *layer)
+{
+  CustomData_add_layer(&dm->faceData, type, alloctype, layer, dm->numTessFaceData);
+}
+
+void DM_add_loop_layer(DerivedMesh *dm, int type, eCDAllocType alloctype, void *layer)
+{
+  CustomData_add_layer(&dm->loopData, type, alloctype, layer, dm->numLoopData);
+}
+
+void DM_add_poly_layer(DerivedMesh *dm, int type, eCDAllocType alloctype, void *layer)
+{
+  CustomData_add_layer(&dm->polyData, type, alloctype, layer, dm->numPolyData);
+}
+
+void *DM_get_vert_data(DerivedMesh *dm, int index, int type)
+{
+  BLI_assert(index >= 0 && index < dm->getNumVerts(dm));
+  return CustomData_get(&dm->vertData, index, type);
+}
+
+void *DM_get_edge_data(DerivedMesh *dm, int index, int type)
+{
+  BLI_assert(index >= 0 && index < dm->getNumEdges(dm));
+  return CustomData_get(&dm->edgeData, index, type);
+}
+
+void *DM_get_tessface_data(DerivedMesh *dm, int index, int type)
+{
+  BLI_assert(index >= 0 && index < dm->getNumTessFaces(dm));
+  return CustomData_get(&dm->faceData, index, type);
+}
+
+void *DM_get_poly_data(DerivedMesh *dm, int index, int type)
+{
+  BLI_assert(index >= 0 && index < dm->getNumPolys(dm));
+  return CustomData_get(&dm->polyData, index, type);
+}
+
+void *DM_get_vert_data_layer(DerivedMesh *dm, int type)
+{
+  if (type == CD_MVERT) {
+    return dm->getVertArray(dm);
+  }
+
+  return CustomData_get_layer(&dm->vertData, type);
+}
+
+void *DM_get_edge_data_layer(DerivedMesh *dm, int type)
+{
+  if (type == CD_MEDGE) {
+    return dm->getEdgeArray(dm);
+  }
+
+  return CustomData_get_layer(&dm->edgeData, type);
+}
+
+void *DM_get_tessface_data_layer(DerivedMesh *dm, int type)
+{
+  if (type == CD_MFACE) {
+    return dm->getTessFaceArray(dm);
+  }
+
+  return CustomData_get_layer(&dm->faceData, type);
+}
+
+void *DM_get_poly_data_layer(DerivedMesh *dm, int type)
+{
+  return CustomData_get_layer(&dm->polyData, type);
+}
+
+void *DM_get_loop_data_layer(DerivedMesh *dm, int type)
+{
+  return CustomData_get_layer(&dm->loopData, type);
+}
+
+void DM_copy_vert_data(
+    DerivedMesh *source, DerivedMesh *dest, int source_index, int dest_index, int count)
+{
+  CustomData_copy_data(&source->vertData, &dest->vertData, source_index, dest_index, count);
+}
+
+/**
+ * interpolates vertex data from the vertices indexed by src_indices in the
+ * source mesh using the given weights and stores the result in the vertex
+ * indexed by dest_index in the dest mesh
+ */
+void DM_interp_vert_data(DerivedMesh *source,
+                         DerivedMesh *dest,
+                         int *src_indices,
+                         float *weights,
+                         int count,
+                         int dest_index)
+{
+  CustomData_interp(
+      &source->vertData, &dest->vertData, src_indices, weights, nullptr, count, dest_index);
+}
+
+static float (*get_editbmesh_orco_verts(BMEditMesh *em))[3]
+{
+  BMIter iter;
+  BMVert *eve;
+  float(*orco)[3];
+  int i;
+
+  /* these may not really be the orco's, but it's only for preview.
+   * could be solver better once, but isn't simple */
+
+  orco = (float(*)[3])MEM_malloc_arrayN(em->bm->totvert, sizeof(float[3]), "BMEditMesh Orco");
+
+  BM_ITER_MESH_INDEX (eve, &iter, em->bm, BM_VERTS_OF_MESH, i) {
+    copy_v3_v3(orco[i], eve->co);
+  }
+
+  return orco;
+}
+
+/* orco custom data layer */
+static float (*get_orco_coords(Object *ob, BMEditMesh *em, int layer, int *free))[3]
+{
+  *free = 0;
+
+  if (layer == CD_ORCO) {
+    /* get original coordinates */
+    *free = 1;
+
+    if (em) {
+      return get_editbmesh_orco_verts(em);
+    }
+    return BKE_mesh_orco_verts_get(ob);
+  }
+  if (layer == CD_CLOTH_ORCO) {
+    /* apply shape key for cloth, this should really be solved
+     * by a more flexible customdata system, but not simple */
+    if (!em) {
+      ClothModifierData *clmd = (ClothModifierData *)BKE_modifiers_findby_type(
+          ob, eModifierType_Cloth);
+      KeyBlock *kb = BKE_keyblock_from_key(BKE_key_from_object(ob),
+                                           clmd->sim_parms->shapekey_rest);
+
+      if (kb && kb->data) {
+        return (float(*)[3])kb->data;
+      }
+    }
+
+    return nullptr;
+  }
+
+  return nullptr;
+}
+
+static Mesh *create_orco_mesh(Object *ob, Mesh *me, BMEditMesh *em, int layer)
+{
+  Mesh *mesh;
+  float(*orco)[3];
+  int free;
+
+  if (em) {
+    mesh = BKE_mesh_from_bmesh_for_eval_nomain(em->bm, nullptr, me);
+  }
+  else {
+    mesh = BKE_mesh_copy_for_eval(me, true);
+  }
+
+  orco = get_orco_coords(ob, em, layer, &free);
+
+  if (orco) {
+    BKE_mesh_vert_coords_apply(mesh, orco);
+    if (free) {
+      MEM_freeN(orco);
+    }
+  }
+
+  return mesh;
+}
+
+static void add_orco_mesh(Object *ob, BMEditMesh *em, Mesh *mesh, Mesh *mesh_orco, int layer)
+{
+  float(*orco)[3], (*layerorco)[3];
+  int totvert, free;
+
+  totvert = mesh->totvert;
+
+  if (mesh_orco) {
+    free = 1;
+
+    if (mesh_orco->totvert == totvert) {
+      orco = BKE_mesh_vert_coords_alloc(mesh_orco, nullptr);
+    }
+    else {
+      orco = BKE_mesh_vert_coords_alloc(mesh, nullptr);
+    }
+  }
+  else {
+    /* TODO(sybren): totvert should potentially change here, as ob->data
+     * or em may have a different number of vertices than dm. */
+    orco = get_orco_coords(ob, em, layer, &free);
+  }
+
+  if (orco) {
+    if (layer == CD_ORCO) {
+      BKE_mesh_orco_verts_transform((Mesh *)ob->data, orco, totvert, 0);
+    }
+
+    if (!(layerorco = (float(*)[3])CustomData_get_layer(&mesh->vdata, layer))) {
+      CustomData_add_layer(&mesh->vdata, layer, CD_CALLOC, nullptr, mesh->totvert);
+      BKE_mesh_update_customdata_pointers(mesh, false);
+
+      layerorco = (float(*)[3])CustomData_get_layer(&mesh->vdata, layer);
+    }
+
+    memcpy(layerorco, orco, sizeof(float[3]) * totvert);
+    if (free) {
+      MEM_freeN(orco);
+    }
+  }
+}
+
+static void mesh_calc_modifier_final_normals(const Mesh *mesh_input,
+                                             const CustomData_MeshMasks *final_datamask,
+                                             const bool sculpt_dyntopo,
+                                             Mesh *mesh_final)
+{
+  /* Compute normals. */
+  const bool do_loop_normals = ((mesh_input->flag & ME_AUTOSMOOTH) != 0 ||
+                                (final_datamask->lmask & CD_MASK_NORMAL) != 0);
+  /* Some modifiers may need this info from their target (other) object,
+   * simpler to generate it here as well.
+   * Note that they will always be generated when no loop normals are computed,
+   * since they are needed by drawing code. */
+  const bool do_poly_normals = ((final_datamask->pmask & CD_MASK_NORMAL) != 0);
+
+  /* In case we also need poly normals, add the layer and compute them here
+   * (BKE_mesh_calc_normals_split() assumes that if that data exists, it is always valid). */
+  if (do_poly_normals) {
+    if (!CustomData_has_layer(&mesh_final->pdata, CD_NORMAL)) {
+      float(*polynors)[3] = (float(*)[3])CustomData_add_layer(
+          &mesh_final->pdata, CD_NORMAL, CD_CALLOC, nullptr, mesh_final->totpoly);
+      BKE_mesh_calc_normals_poly(mesh_final->mvert,
+                                 nullptr,
+                                 mesh_final->totvert,
+                                 mesh_final->mloop,
+                                 mesh_final->mpoly,
+                                 mesh_final->totloop,
+                                 mesh_final->totpoly,
+                                 polynors,
+                                 false);
+    }
+  }
+
+  if (do_loop_normals) {
+    /* Compute loop normals (note: will compute poly and vert normals as well, if needed!) */
+    BKE_mesh_calc_normals_split(mesh_final);
+    BKE_mesh_tessface_clear(mesh_final);
+  }
+
+  if (sculpt_dyntopo == false) {
+    /* watch this! after 2.75a we move to from tessface to looptri (by default) */
+    if (final_datamask->fmask & CD_MASK_MFACE) {
+      BKE_mesh_tessface_ensure(mesh_final);
+    }
+
+    /* without this, drawing ngon tri's faces will show ugly tessellated face
+     * normals and will also have to calculate normals on the fly, try avoid
+     * this where possible since calculating polygon normals isn't fast,
+     * note that this isn't a problem for subsurf (only quads) or editmode
+     * which deals with drawing differently.
+     *
+     * Only calc vertex normals if they are flagged as dirty.
+     * If using loop normals, poly nors have already been computed.
+     */
+    if (!do_loop_normals) {
+      BKE_mesh_ensure_normals_for_display(mesh_final);
+    }
+  }
+
+  /* Some modifiers, like data-transfer, may generate those data as temp layer,
+   * we do not want to keep them, as they are used by display code when available
+   * (i.e. even if autosmooth is disabled). */
+  if (!do_loop_normals && CustomData_has_layer(&mesh_final->ldata, CD_NORMAL)) {
+    CustomData_free_layers(&mesh_final->ldata, CD_NORMAL, mesh_final->totloop);
+  }
+}
+
+/* Does final touches to the final evaluated mesh, making sure it is perfectly usable.
+ *
+ * This is needed because certain information is not passed along intermediate meshes allocated
+ * during stack evaluation.
+ */
+static void mesh_calc_finalize(const Mesh *mesh_input, Mesh *mesh_eval)
+{
+  /* Make sure the name is the same. This is because mesh allocation from template does not
+   * take care of naming. */
+  BLI_strncpy(mesh_eval->id.name, mesh_input->id.name, sizeof(mesh_eval->id.name));
+  /* Make evaluated mesh to share same edit mesh pointer as original and copied meshes. */
+  mesh_eval->edit_mesh = mesh_input->edit_mesh;
+}
+
+void BKE_mesh_wrapper_deferred_finalize(Mesh *me_eval,
+                                        const CustomData_MeshMasks *cd_mask_finalize)
+{
+  if (me_eval->runtime.wrapper_type_finalize & (1 << ME_WRAPPER_TYPE_BMESH)) {
+    editbmesh_calc_modifier_final_normals(me_eval, cd_mask_finalize);
+    me_eval->runtime.wrapper_type_finalize &= ~(1 << ME_WRAPPER_TYPE_BMESH);
+  }
+  BLI_assert(me_eval->runtime.wrapper_type_finalize == 0);
+}
+
+static void mesh_calc_modifiers(struct Depsgraph *depsgraph,
+                                Scene *scene,
+                                Object *ob,
+                                int useDeform,
+                                const bool need_mapping,
+                                const CustomData_MeshMasks *dataMask,
+                                const int index,
+                                const bool use_cache,
+                                const bool allow_shared_mesh,
+                                /* return args */
+                                Mesh **r_deform,
+                                Mesh **r_final)
+{
+  /* Input and final mesh. Final mesh is only created the moment the first
+   * constructive modifier is executed, or a deform modifier needs normals
+   * or certain data layers. */
+  Mesh *mesh_input = (Mesh *)ob->data;
+  Mesh *mesh_final = nullptr;
+  Mesh *mesh_deform = nullptr;
+  BLI_assert((mesh_input->id.tag & LIB_TAG_COPIED_ON_WRITE_EVAL_RESULT) == 0);
+
+  /* Deformed vertex locations array. Deform only modifier need this type of
+   * float array rather than MVert*. Tracked along with mesh_final as an
+   * optimization to avoid copying coordinates back and forth if there are
+   * multiple sequential deform only modifiers. */
+  float(*deformed_verts)[3] = nullptr;
+  int num_deformed_verts = mesh_input->totvert;
+  bool isPrevDeform = false;
+
+  /* Mesh with constructive modifiers but no deformation applied. Tracked
+   * along with final mesh if undeformed / orco coordinates are requested
+   * for texturing. */
+  Mesh *mesh_orco = nullptr;
+  Mesh *mesh_orco_cloth = nullptr;
+
+  /* Modifier evaluation modes. */
+  const bool use_render = (DEG_get_mode(depsgraph) == DAG_EVAL_RENDER);
+  const int required_mode = use_render ? eModifierMode_Render : eModifierMode_Realtime;
+
+  /* Sculpt can skip certain modifiers. */
+  const bool has_multires = BKE_sculpt_multires_active(scene, ob) != nullptr;
+  bool multires_applied = false;
+  const bool sculpt_mode = ob->mode & OB_MODE_SCULPT && ob->sculpt && !use_render;
+  const bool sculpt_dyntopo = (sculpt_mode && ob->sculpt->bm) && !use_render;
+
+  /* Modifier evaluation contexts for different types of modifiers. */
+  ModifierApplyFlag apply_render = use_render ? MOD_APPLY_RENDER : (ModifierApplyFlag)0;
+  ModifierApplyFlag apply_cache = use_cache ? MOD_APPLY_USECACHE : (ModifierApplyFlag)0;
+  const ModifierEvalContext mectx = {
+      depsgraph, ob, (ModifierApplyFlag)(apply_render | apply_cache)};
+  const ModifierEvalContext mectx_orco = {
+      depsgraph, ob, (ModifierApplyFlag)(apply_render | MOD_APPLY_ORCO)};
+
+  /* Get effective list of modifiers to execute. Some effects like shape keys
+   * are added as virtual modifiers before the user created modifiers. */
+  VirtualModifierData virtualModifierData;
+  ModifierData *firstmd = BKE_modifiers_get_virtual_modifierlist(ob, &virtualModifierData);
+  ModifierData *md = firstmd;
+
+  /* Preview colors by modifiers such as dynamic paint, to show the results
+   * even if the resulting data is not used in a material. Only in object mode.
+   * TODO: this is broken, not drawn by the drawn manager. */
+  const bool do_mod_mcol = (ob->mode == OB_MODE_OBJECT);
+  ModifierData *previewmd = nullptr;
+  CustomData_MeshMasks previewmask = {0};
+  if (do_mod_mcol) {
+    /* Find the last active modifier generating a preview, or nullptr if none. */
+    /* XXX Currently, DPaint modifier just ignores this.
+     *     Needs a stupid hack...
+     *     The whole "modifier preview" thing has to be (re?)designed, anyway! */
+    previewmd = BKE_modifier_get_last_preview(scene, md, required_mode);
+  }
+
+  /* Compute accumulated datamasks needed by each modifier. It helps to do
+   * this fine grained so that for example vertex groups are preserved up to
+   * an armature modifier, but not through a following subsurf modifier where
+   * subdividing them is expensive. */
+  CustomData_MeshMasks final_datamask = *dataMask;
+  CDMaskLink *datamasks = BKE_modifier_calc_data_masks(
+      scene, ob, md, &final_datamask, required_mode, previewmd, &previewmask);
+  CDMaskLink *md_datamask = datamasks;
+  /* XXX Always copying POLYINDEX, else tessellated data are no more valid! */
+  CustomData_MeshMasks append_mask = CD_MASK_BAREMESH_ORIGINDEX;
+
+  /* Clear errors before evaluation. */
+  BKE_modifiers_clear_errors(ob);
+
+  /* Apply all leading deform modifiers. */
+  if (useDeform) {
+    for (; md; md = md->next, md_datamask = md_datamask->next) {
+      const ModifierTypeInfo *mti = BKE_modifier_get_info((ModifierType)md->type);
+
+      if (!BKE_modifier_is_enabled(scene, md, required_mode)) {
+        continue;
+      }
+
+      if (useDeform < 0 && mti->dependsOnTime && mti->dependsOnTime(md)) {
+        continue;
+      }
+
+      if (mti->type == eModifierTypeType_OnlyDeform && !sculpt_dyntopo) {
+        if (!deformed_verts) {
+          deformed_verts = BKE_mesh_vert_coords_alloc(mesh_input, &num_deformed_verts);
+        }
+        else if (isPrevDeform && mti->dependsOnNormals && mti->dependsOnNormals(md)) {
+          if (mesh_final == nullptr) {
+            mesh_final = BKE_mesh_copy_for_eval(mesh_input, true);
+            ASSERT_IS_VALID_MESH(mesh_final);
+          }
+          BKE_mesh_vert_coords_apply(mesh_final, deformed_verts);
+        }
+
+        BKE_modifier_deform_verts(md, &mectx, mesh_final, deformed_verts, num_deformed_verts);
+
+        isPrevDeform = true;
+      }
+      else {
+        break;
+      }
+
+      /* grab modifiers until index i */
+      if ((index != -1) && (BLI_findindex(&ob->modifiers, md) >= index)) {
+        md = nullptr;
+        break;
+      }
+    }
+
+    /* Result of all leading deforming modifiers is cached for
+     * places that wish to use the original mesh but with deformed
+     * coordinates (like vertex paint). */
+    if (r_deform) {
+      mesh_deform = BKE_mesh_copy_for_eval(mesh_input, true);
+
+      if (deformed_verts) {
+        BKE_mesh_vert_coords_apply(mesh_deform, deformed_verts);
+      }
+    }
+  }
+
+  /* Apply all remaining constructive and deforming modifiers. */
+  bool have_non_onlydeform_modifiers_appled = false;
+  for (; md; md = md->next, md_datamask = md_datamask->next) {
+    const ModifierTypeInfo *mti = BKE_modifier_get_info((ModifierType)md->type);
+
+    if (!BKE_modifier_is_enabled(scene, md, required_mode)) {
+      continue;
+    }
+
+    if (mti->type == eModifierTypeType_OnlyDeform && !useDeform) {
+      continue;
+    }
+
+    if ((mti->flags & eModifierTypeFlag_RequiresOriginalData) &&
+        have_non_onlydeform_modifiers_appled) {
+      BKE_modifier_set_error(ob, md, "Modifier requires original data, bad stack position");
+      continue;
+    }
+
+    if (sculpt_mode && (!has_multires || multires_applied || sculpt_dyntopo)) {
+      bool unsupported = false;
+
+      if (md->type == eModifierType_Multires && ((MultiresModifierData *)md)->sculptlvl == 0) {
+        /* If multires is on level 0 skip it silently without warning message. */
+        if (!sculpt_dyntopo) {
+          continue;
+        }
+      }
+
+      if (sculpt_dyntopo) {
+        unsupported = true;
+      }
+
+      if (scene->toolsettings->sculpt->flags & SCULPT_ONLY_DEFORM) {
+        unsupported |= (mti->type != eModifierTypeType_OnlyDeform);
+      }
+
+      unsupported |= multires_applied;
+
+      if (unsupported) {
+        if (sculpt_dyntopo) {
+          BKE_modifier_set_error(ob, md, "Not supported in dyntopo");
+        }
+        else {
+          BKE_modifier_set_error(ob, md, "Not supported in sculpt mode");
+        }
+        continue;
+      }
+    }
+
+    if (need_mapping && !BKE_modifier_supports_mapping(md)) {
+      continue;
+    }
+
+    if (useDeform < 0 && mti->dependsOnTime && mti->dependsOnTime(md)) {
+      continue;
+    }
+
+    /* Add orco mesh as layer if needed by this modifier. */
+    if (mesh_final && mesh_orco && mti->requiredDataMask) {
+      CustomData_MeshMasks mask = {0};
+      mti->requiredDataMask(ob, md, &mask);
+      if (mask.vmask & CD_MASK_ORCO) {
+        add_orco_mesh(ob, nullptr, mesh_final, mesh_orco, CD_ORCO);
+      }
+    }
+
+    /* How to apply modifier depends on (a) what we already have as
+     * a result of previous modifiers (could be a Mesh or just
+     * deformed vertices) and (b) what type the modifier is. */
+    if (mti->type == eModifierTypeType_OnlyDeform) {
+      /* No existing verts to deform, need to build them. */
+      if (!deformed_verts) {
+        if (mesh_final) {
+          /* Deforming a mesh, read the vertex locations
+           * out of the mesh and deform them. Once done with this
+           * run of deformers verts will be written back. */
+          deformed_verts = BKE_mesh_vert_coords_alloc(mesh_final, &num_deformed_verts);
+        }
+        else {
+          deformed_verts = BKE_mesh_vert_coords_alloc(mesh_input, &num_deformed_verts);
+        }
+      }
+      /* if this is not the last modifier in the stack then recalculate the normals
+       * to avoid giving bogus normals to the next modifier see: T23673. */
+      else if (isPrevDeform && mti->dependsOnNormals && mti->dependsOnNormals(md)) {
+        if (mesh_final == nullptr) {
+          mesh_final = BKE_mesh_copy_for_eval(mesh_input, true);
+          ASSERT_IS_VALID_MESH(mesh_final);
+        }
+        BKE_mesh_vert_coords_apply(mesh_final, deformed_verts);
+      }
+      BKE_modifier_deform_verts(md, &mectx, mesh_final, deformed_verts, num_deformed_verts);
+    }
+    else {
+      bool check_for_needs_mapping = false;
+      /* apply vertex coordinates or build a Mesh as necessary */
+      if (mesh_final != nullptr) {
+        if (have_non_onlydeform_modifiers_appled == false) {
+          /* If we only deformed, we won't have initialized #CD_ORIGINDEX.
+           * as this is the only part of the function that initializes mapping. */
+          check_for_needs_mapping = true;
+        }
+      }
+      else {
+        mesh_final = BKE_mesh_copy_for_eval(mesh_input, true);
+        ASSERT_IS_VALID_MESH(mesh_final);
+        check_for_needs_mapping = true;
+      }
+
+      if (deformed_verts) {
+        BKE_mesh_vert_coords_apply(mesh_final, deformed_verts);
+      }
+
+      have_non_onlydeform_modifiers_appled = true;
+
+      /* determine which data layers are needed by following modifiers */
+      CustomData_MeshMasks nextmask = md_datamask->next ? md_datamask->next->mask : final_datamask;
+
+      if (check_for_needs_mapping) {
+        /* Initialize original indices the first time we evaluate a
+         * constructive modifier. Modifiers will then do mapping mostly
+         * automatic by copying them through CustomData_copy_data along
+         * with other data.
+         *
+         * These are created when either requested by evaluation, or if
+         * following modifiers requested them. */
+        if (need_mapping ||
+            ((nextmask.vmask | nextmask.emask | nextmask.pmask) & CD_MASK_ORIGINDEX)) {
+          /* calc */
+          CustomData_add_layer(
+              &mesh_final->vdata, CD_ORIGINDEX, CD_CALLOC, nullptr, mesh_final->totvert);
+          CustomData_add_layer(
+              &mesh_final->edata, CD_ORIGINDEX, CD_CALLOC, nullptr, mesh_final->totedge);
+          CustomData_add_layer(
+              &mesh_final->pdata, CD_ORIGINDEX, CD_CALLOC, nullptr, mesh_final->totpoly);
+
+          /* Not worth parallelizing this,
+           * gives less than 0.1% overall speedup in best of best cases... */
+          range_vn_i((int *)CustomData_get_layer(&mesh_final->vdata, CD_ORIGINDEX),
+                     mesh_final->totvert,
+                     0);
+          range_vn_i((int *)CustomData_get_layer(&mesh_final->edata, CD_ORIGINDEX),
+                     mesh_final->totedge,
+                     0);
+          range_vn_i((int *)CustomData_get_layer(&mesh_final->pdata, CD_ORIGINDEX),
+                     mesh_final->totpoly,
+                     0);
+        }
+      }
+
+      /* set the Mesh to only copy needed data */
+      CustomData_MeshMasks mask = md_datamask->mask;
+      /* needMapping check here fixes bug T28112, otherwise it's
+       * possible that it won't be copied */
+      CustomData_MeshMasks_update(&mask, &append_mask);
+      if (need_mapping) {
+        mask.vmask |= CD_MASK_ORIGINDEX;
+        mask.emask |= CD_MASK_ORIGINDEX;
+        mask.pmask |= CD_MASK_ORIGINDEX;
+      }
+      mesh_set_only_copy(mesh_final, &mask);
+
+      /* add cloth rest shape key if needed */
+      if (mask.vmask & CD_MASK_CLOTH_ORCO) {
+        add_orco_mesh(ob, nullptr, mesh_final, mesh_orco, CD_CLOTH_ORCO);
+      }
+
+      /* add an origspace layer if needed */
+      if ((md_datamask->mask.lmask) & CD_MASK_ORIGSPACE_MLOOP) {
+        if (!CustomData_has_layer(&mesh_final->ldata, CD_ORIGSPACE_MLOOP)) {
+          CustomData_add_layer(
+              &mesh_final->ldata, CD_ORIGSPACE_MLOOP, CD_CALLOC, nullptr, mesh_final->totloop);
+          mesh_init_origspace(mesh_final);
+        }
+      }
+
+      Mesh *mesh_next = BKE_modifier_modify_mesh(md, &mectx, mesh_final);
+      ASSERT_IS_VALID_MESH(mesh_next);
+
+      if (mesh_next) {
+        /* if the modifier returned a new mesh, release the old one */
+        if (mesh_final != mesh_next) {
+          BLI_assert(mesh_final != mesh_input);
+          BKE_id_free(nullptr, mesh_final);
+        }
+        mesh_final = mesh_next;
+
+        if (deformed_verts) {
+          MEM_freeN(deformed_verts);
+          deformed_verts = nullptr;
+        }
+      }
+
+      /* create an orco mesh in parallel */
+      if (nextmask.vmask & CD_MASK_ORCO) {
+        if (!mesh_orco) {
+          mesh_orco = create_orco_mesh(ob, mesh_input, nullptr, CD_ORCO);
+        }
+
+        nextmask.vmask &= ~CD_MASK_ORCO;
+        CustomData_MeshMasks temp_cddata_masks = {0};
+        temp_cddata_masks.vmask = CD_MASK_ORIGINDEX;
+        temp_cddata_masks.emask = CD_MASK_ORIGINDEX;
+        temp_cddata_masks.fmask = CD_MASK_ORIGINDEX;
+        temp_cddata_masks.pmask = CD_MASK_ORIGINDEX;
+
+        if (mti->requiredDataMask != nullptr) {
+          mti->requiredDataMask(ob, md, &temp_cddata_masks);
+        }
+        CustomData_MeshMasks_update(&temp_cddata_masks, &nextmask);
+        mesh_set_only_copy(mesh_orco, &temp_cddata_masks);
+
+        mesh_next = BKE_modifier_modify_mesh(md, &mectx_orco, mesh_orco);
+        ASSERT_IS_VALID_MESH(mesh_next);
+
+        if (mesh_next) {
+          /* if the modifier returned a new mesh, release the old one */
+          if (mesh_orco != mesh_next) {
+            BLI_assert(mesh_orco != mesh_input);
+            BKE_id_free(nullptr, mesh_orco);
+          }
+
+          mesh_orco = mesh_next;
+        }
+      }
+
+      /* create cloth orco mesh in parallel */
+      if (nextmask.vmask & CD_MASK_CLOTH_ORCO) {
+        if (!mesh_orco_cloth) {
+          mesh_orco_cloth = create_orco_mesh(ob, mesh_input, nullptr, CD_CLOTH_ORCO);
+        }
+
+        nextmask.vmask &= ~CD_MASK_CLOTH_ORCO;
+        nextmask.vmask |= CD_MASK_ORIGINDEX;
+        nextmask.emask |= CD_MASK_ORIGINDEX;
+        nextmask.pmask |= CD_MASK_ORIGINDEX;
+        mesh_set_only_copy(mesh_orco_cloth, &nextmask);
+
+        mesh_next = BKE_modifier_modify_mesh(md, &mectx_orco, mesh_orco_cloth);
+        ASSERT_IS_VALID_MESH(mesh_next);
+
+        if (mesh_next) {
+          /* if the modifier returned a new mesh, release the old one */
+          if (mesh_orco_cloth != mesh_next) {
+            BLI_assert(mesh_orco != mesh_input);
+            BKE_id_free(nullptr, mesh_orco_cloth);
+          }
+
+          mesh_orco_cloth = mesh_next;
+        }
+      }
+
+      /* in case of dynamic paint, make sure preview mask remains for following modifiers */
+      /* XXX Temp and hackish solution! */
+      if (md->type == eModifierType_DynamicPaint) {
+        append_mask.lmask |= CD_MASK_PREVIEW_MLOOPCOL;
+      }
+
+      mesh_final->runtime.deformed_only = false;
+    }
+
+    isPrevDeform = (mti->type == eModifierTypeType_OnlyDeform);
+
+    /* grab modifiers until index i */
+    if ((index != -1) && (BLI_findindex(&ob->modifiers, md) >= index)) {
+      break;
+    }
+
+    if (sculpt_mode && md->type == eModifierType_Multires) {
+      multires_applied = true;
+    }
+  }
+
+  BLI_linklist_free((LinkNode *)datamasks, nullptr);
+
+  for (md = firstmd; md; md = md->next) {
+    BKE_modifier_free_temporary_data(md);
+  }
+
+  /* Yay, we are done. If we have a Mesh and deformed vertices,
+   * we need to apply these back onto the Mesh. If we have no
+   * Mesh then we need to build one. */
+  if (mesh_final == nullptr) {
+    /* Note: this check on cdmask is a bit dodgy, it handles the issue at stake here (see T68211),
+     * but other cases might require similar handling?
+     * Could be a good idea to define a proper CustomData_MeshMask for that then. */
+    if (deformed_verts == nullptr && allow_shared_mesh &&
+        (final_datamask.lmask & CD_MASK_NORMAL) == 0 &&
+        (final_datamask.pmask & CD_MASK_NORMAL) == 0) {
+      mesh_final = mesh_input;
+    }
+    else {
+      mesh_final = BKE_mesh_copy_for_eval(mesh_input, true);
+    }
+  }
+  if (deformed_verts) {
+    BKE_mesh_vert_coords_apply(mesh_final, deformed_verts);
+    MEM_freeN(deformed_verts);
+    deformed_verts = nullptr;
+  }
+
+  /* Denotes whether the object which the modifier stack came from owns the mesh or whether the
+   * mesh is shared across multiple objects since there are no effective modifiers. */
+  const bool is_own_mesh = (mesh_final != mesh_input);
+
+  /* Add orco coordinates to final and deformed mesh if requested. */
+  if (final_datamask.vmask & CD_MASK_ORCO) {
+    /* No need in ORCO layer if the mesh was not deformed or modified: undeformed mesh in this case
+     * matches input mesh. */
+    if (is_own_mesh) {
+      add_orco_mesh(ob, nullptr, mesh_final, mesh_orco, CD_ORCO);
+    }
+
+    if (mesh_deform) {
+      add_orco_mesh(ob, nullptr, mesh_deform, nullptr, CD_ORCO);
+    }
+  }
+
+  if (mesh_orco) {
+    BKE_id_free(nullptr, mesh_orco);
+  }
+  if (mesh_orco_cloth) {
+    BKE_id_free(nullptr, mesh_orco_cloth);
+  }
+
+  /* Compute normals. */
+  if (is_own_mesh) {
+    mesh_calc_modifier_final_normals(mesh_input, &final_datamask, sculpt_dyntopo, mesh_final);
+  }
+  else {
+    Mesh_Runtime *runtime = &mesh_input->runtime;
+    if (runtime->mesh_eval == nullptr) {
+      BLI_assert(runtime->eval_mutex != nullptr);
+      BLI_mutex_lock((ThreadMutex *)runtime->eval_mutex);
+      if (runtime->mesh_eval == nullptr) {
+        mesh_final = BKE_mesh_copy_for_eval(mesh_input, true);
+        mesh_calc_modifier_final_normals(mesh_input, &final_datamask, sculpt_dyntopo, mesh_final);
+        mesh_calc_finalize(mesh_input, mesh_final);
+        runtime->mesh_eval = mesh_final;
+      }
+      BLI_mutex_unlock((ThreadMutex *)runtime->eval_mutex);
+    }
+    mesh_final = runtime->mesh_eval;
+  }
+
+  if (is_own_mesh) {
+    mesh_calc_finalize(mesh_input, mesh_final);
+  }
+
+  /* Return final mesh */
+  *r_final = mesh_final;
+  if (r_deform) {
+    *r_deform = mesh_deform;
+  }
+}
+
+float (*editbmesh_vert_coords_alloc(BMEditMesh *em, int *r_vert_len))[3]
+{
+  BMIter iter;
+  BMVert *eve;
+  float(*cos)[3];
+  int i;
+
+  *r_vert_len = em->bm->totvert;
+
+  cos = (float(*)[3])MEM_malloc_arrayN(em->bm->totvert, sizeof(float[3]), "vertexcos");
+
+  BM_ITER_MESH_INDEX (eve, &iter, em->bm, BM_VERTS_OF_MESH, i) {
+    copy_v3_v3(cos[i], eve->co);
+  }
+
+  return cos;
+}
+
+bool editbmesh_modifier_is_enabled(Scene *scene,
+                                   const Object *ob,
+                                   ModifierData *md,
+                                   bool has_prev_mesh)
+{
+  const ModifierTypeInfo *mti = BKE_modifier_get_info((ModifierType)md->type);
+  const int required_mode = eModifierMode_Realtime | eModifierMode_Editmode;
+
+  if (!BKE_modifier_is_enabled(scene, md, required_mode)) {
+    return false;
+  }
+
+  if ((mti->flags & eModifierTypeFlag_RequiresOriginalData) && has_prev_mesh) {
+    BKE_modifier_set_error(ob, md, "Modifier requires original data, bad stack position");
+    return false;
+  }
+
+  return true;
+}
+
+static void editbmesh_calc_modifier_final_normals(Mesh *mesh_final,
+                                                  const CustomData_MeshMasks *final_datamask)
+{
+  if (mesh_final->runtime.wrapper_type != ME_WRAPPER_TYPE_MDATA) {
+    /* Generated at draw time. */
+    mesh_final->runtime.wrapper_type_finalize = (1 << mesh_final->runtime.wrapper_type);
+    return;
+  }
+
+  const bool do_loop_normals = ((mesh_final->flag & ME_AUTOSMOOTH) != 0 ||
+                                (final_datamask->lmask & CD_MASK_NORMAL) != 0);
+  /* Some modifiers may need this info from their target (other) object,
+   * simpler to generate it here as well. */
+  const bool do_poly_normals = ((final_datamask->pmask & CD_MASK_NORMAL) != 0);
+
+  /* In case we also need poly normals, add the layer and compute them here
+   * (BKE_mesh_calc_normals_split() assumes that if that data exists, it is always valid). */
+  if (do_poly_normals) {
+    if (!CustomData_has_layer(&mesh_final->pdata, CD_NORMAL)) {
+      float(*polynors)[3] = (float(*)[3])CustomData_add_layer(
+          &mesh_final->pdata, CD_NORMAL, CD_CALLOC, nullptr, mesh_final->totpoly);
+      BKE_mesh_calc_normals_poly(mesh_final->mvert,
+                                 nullptr,
+                                 mesh_final->totvert,
+                                 mesh_final->mloop,
+                                 mesh_final->mpoly,
+                                 mesh_final->totloop,
+                                 mesh_final->totpoly,
+                                 polynors,
+                                 false);
+    }
+  }
+
+  if (do_loop_normals) {
+    /* Compute loop normals */
+    BKE_mesh_calc_normals_split(mesh_final);
+    BKE_mesh_tessface_clear(mesh_final);
+  }
+
+  /* BMESH_ONLY, ensure tessface's used for drawing,
+   * but don't recalculate if the last modifier in the stack gives us tessfaces
+   * check if the derived meshes are DM_TYPE_EDITBMESH before calling, this isn't essential
+   * but quiets annoying error messages since tessfaces wont be created. */
+  if (final_datamask->fmask & CD_MASK_MFACE) {
+    if (mesh_final->edit_mesh == nullptr) {
+      BKE_mesh_tessface_ensure(mesh_final);
+    }
+  }
+
+  /* same as mesh_calc_modifiers (if using loop normals, poly nors have already been computed). */
+  if (!do_loop_normals) {
+    BKE_mesh_ensure_normals_for_display(mesh_final);
+
+    /* Some modifiers, like data-transfer, may generate those data, we do not want to keep them,
+     * as they are used by display code when available (i.e. even if autosmooth is disabled). */
+    if (CustomData_has_layer(&mesh_final->ldata, CD_NORMAL)) {
+      CustomData_free_layers(&mesh_final->ldata, CD_NORMAL, mesh_final->totloop);
+    }
+  }
+}
+
+static void editbmesh_calc_modifiers(struct Depsgraph *depsgraph,
+                                     Scene *scene,
+                                     Object *ob,
+                                     BMEditMesh *em_input,
+                                     const CustomData_MeshMasks *dataMask,
+                                     /* return args */
+                                     Mesh **r_cage,
+                                     Mesh **r_final)
+{
+  /* Input and final mesh. Final mesh is only created the moment the first
+   * constructive modifier is executed, or a deform modifier needs normals
+   * or certain data layers. */
+  Mesh *mesh_input = (Mesh *)ob->data;
+  Mesh *mesh_final = nullptr;
+  Mesh *mesh_cage = nullptr;
+
+  /* Deformed vertex locations array. Deform only modifier need this type of
+   * float array rather than MVert*. Tracked along with mesh_final as an
+   * optimization to avoid copying coordinates back and forth if there are
+   * multiple sequential deform only modifiers. */
+  float(*deformed_verts)[3] = nullptr;
+  int num_deformed_verts = 0;
+  bool isPrevDeform = false;
+
+  /* Mesh with constructive modifiers but no deformation applied. Tracked
+   * along with final mesh if undeformed / orco coordinates are requested
+   * for texturing. */
+  Mesh *mesh_orco = nullptr;
+
+  /* Modifier evaluation modes. */
+  const int required_mode = eModifierMode_Realtime | eModifierMode_Editmode;
+
+  const bool use_render = (DEG_get_mode(depsgraph) == DAG_EVAL_RENDER);
+  /* Modifier evaluation contexts for different types of modifiers. */
+  ModifierApplyFlag apply_render = use_render ? MOD_APPLY_RENDER : (ModifierApplyFlag)0;
+  const ModifierEvalContext mectx = {
+      depsgraph, ob, (ModifierApplyFlag)(MOD_APPLY_USECACHE | apply_render)};
+  const ModifierEvalContext mectx_orco = {depsgraph, ob, MOD_APPLY_ORCO};
+
+  /* Get effective list of modifiers to execute. Some effects like shape keys
+   * are added as virtual modifiers before the user created modifiers. */
+  VirtualModifierData virtualModifierData;
+  ModifierData *md = BKE_modifiers_get_virtual_modifierlist(ob, &virtualModifierData);
+
+  /* Compute accumulated datamasks needed by each modifier. It helps to do
+   * this fine grained so that for example vertex groups are preserved up to
+   * an armature modifier, but not through a following subsurf modifier where
+   * subdividing them is expensive. */
+  CustomData_MeshMasks final_datamask = *dataMask;
+  CDMaskLink *datamasks = BKE_modifier_calc_data_masks(
+      scene, ob, md, &final_datamask, required_mode, nullptr, nullptr);
+  CDMaskLink *md_datamask = datamasks;
+  CustomData_MeshMasks append_mask = CD_MASK_BAREMESH;
+
+  /* Evaluate modifiers up to certain index to get the mesh cage. */
+  int cageIndex = BKE_modifiers_get_cage_index(scene, ob, nullptr, true);
+  if (r_cage && cageIndex == -1) {
+    mesh_cage = BKE_mesh_wrapper_from_editmesh_with_coords(
+        em_input, &final_datamask, nullptr, mesh_input);
+  }
+
+  /* Clear errors before evaluation. */
+  BKE_modifiers_clear_errors(ob);
+
+  for (int i = 0; md; i++, md = md->next, md_datamask = md_datamask->next) {
+    const ModifierTypeInfo *mti = BKE_modifier_get_info((ModifierType)md->type);
+
+    if (!editbmesh_modifier_is_enabled(scene, ob, md, mesh_final != nullptr)) {
+      continue;
+    }
+
+    /* Add an orco mesh as layer if needed by this modifier. */
+    if (mesh_final && mesh_orco && mti->requiredDataMask) {
+      CustomData_MeshMasks mask = {0};
+      mti->requiredDataMask(ob, md, &mask);
+      if (mask.vmask & CD_MASK_ORCO) {
+        add_orco_mesh(ob, em_input, mesh_final, mesh_orco, CD_ORCO);
+      }
+    }
+
+    /* How to apply modifier depends on (a) what we already have as
+     * a result of previous modifiers (could be a mesh or just
+     * deformed vertices) and (b) what type the modifier is. */
+    if (mti->type == eModifierTypeType_OnlyDeform) {
+      /* No existing verts to deform, need to build them. */
+      if (!deformed_verts) {
+        if (mesh_final) {
+          /* Deforming a derived mesh, read the vertex locations
+           * out of the mesh and deform them. Once done with this
+           * run of deformers verts will be written back. */
+          deformed_verts = BKE_mesh_vert_coords_alloc(mesh_final, &num_deformed_verts);
+        }
+        else {
+          deformed_verts = editbmesh_vert_coords_alloc(em_input, &num_deformed_verts);
+        }
+      }
+      else if (isPrevDeform && mti->dependsOnNormals && mti->dependsOnNormals(md)) {
+        if (mesh_final == nullptr) {
+          mesh_final = BKE_mesh_from_bmesh_for_eval_nomain(em_input->bm, nullptr, mesh_input);
+          ASSERT_IS_VALID_MESH(mesh_final);
+        }
+        BLI_assert(deformed_verts != nullptr);
+        BKE_mesh_vert_coords_apply(mesh_final, deformed_verts);
+      }
+
+      if (mti->deformVertsEM) {
+        BKE_modifier_deform_vertsEM(
+            md, &mectx, em_input, mesh_final, deformed_verts, num_deformed_verts);
+      }
+      else {
+        BKE_modifier_deform_verts(md, &mectx, mesh_final, deformed_verts, num_deformed_verts);
+      }
+    }
+    else {
+      /* apply vertex coordinates or build a DerivedMesh as necessary */
+      if (mesh_final) {
+        if (deformed_verts) {
+          Mesh *mesh_tmp = BKE_mesh_copy_for_eval(mesh_final, false);
+          if (mesh_final != mesh_cage) {
+            BKE_id_free(nullptr, mesh_final);
+          }
+          mesh_final = mesh_tmp;
+          BKE_mesh_vert_coords_apply(mesh_final, deformed_verts);
+        }
+        else if (mesh_final == mesh_cage) {
+          /* 'me' may be changed by this modifier, so we need to copy it. */
+          mesh_final = BKE_mesh_copy_for_eval(mesh_final, false);
+        }
+      }
+      else {
+        mesh_final = BKE_mesh_wrapper_from_editmesh_with_coords(
+            em_input, nullptr, deformed_verts, mesh_input);
+        deformed_verts = nullptr;
+      }
+
+      /* create an orco derivedmesh in parallel */
+      CustomData_MeshMasks mask = md_datamask->mask;
+      if (mask.vmask & CD_MASK_ORCO) {
+        if (!mesh_orco) {
+          mesh_orco = create_orco_mesh(ob, mesh_input, em_input, CD_ORCO);
+        }
+
+        mask.vmask &= ~CD_MASK_ORCO;
+        mask.vmask |= CD_MASK_ORIGINDEX;
+        mask.emask |= CD_MASK_ORIGINDEX;
+        mask.pmask |= CD_MASK_ORIGINDEX;
+        mesh_set_only_copy(mesh_orco, &mask);
+
+        Mesh *mesh_next = BKE_modifier_modify_mesh(md, &mectx_orco, mesh_orco);
+        ASSERT_IS_VALID_MESH(mesh_next);
+
+        if (mesh_next) {
+          /* if the modifier returned a new dm, release the old one */
+          if (mesh_orco && mesh_orco != mesh_next) {
+            BKE_id_free(nullptr, mesh_orco);
+          }
+          mesh_orco = mesh_next;
+        }
+      }
+
+      /* set the DerivedMesh to only copy needed data */
+      CustomData_MeshMasks_update(&mask, &append_mask);
+      /* XXX WHAT? ovewrites mask ??? */
+      /* CD_MASK_ORCO may have been cleared above */
+      mask = md_datamask->mask;
+      mask.vmask |= CD_MASK_ORIGINDEX;
+      mask.emask |= CD_MASK_ORIGINDEX;
+      mask.pmask |= CD_MASK_ORIGINDEX;
+
+      mesh_set_only_copy(mesh_final, &mask);
+
+      if (mask.lmask & CD_MASK_ORIGSPACE_MLOOP) {
+        if (!CustomData_has_layer(&mesh_final->ldata, CD_ORIGSPACE_MLOOP)) {
+          CustomData_add_layer(
+              &mesh_final->ldata, CD_ORIGSPACE_MLOOP, CD_CALLOC, nullptr, mesh_final->totloop);
+          mesh_init_origspace(mesh_final);
+        }
+      }
+
+      Mesh *mesh_next = BKE_modifier_modify_mesh(md, &mectx, mesh_final);
+      ASSERT_IS_VALID_MESH(mesh_next);
+
+      if (mesh_next) {
+        if (mesh_final && mesh_final != mesh_next) {
+          BKE_id_free(nullptr, mesh_final);
+        }
+        mesh_final = mesh_next;
+
+        if (deformed_verts) {
+          MEM_freeN(deformed_verts);
+          deformed_verts = nullptr;
+        }
+      }
+      mesh_final->runtime.deformed_only = false;
+    }
+
+    if (r_cage && i == cageIndex) {
+      if (mesh_final && deformed_verts) {
+        mesh_cage = BKE_mesh_copy_for_eval(mesh_final, false);
+        BKE_mesh_vert_coords_apply(mesh_cage, deformed_verts);
+      }
+      else if (mesh_final) {
+        mesh_cage = mesh_final;
+      }
+      else {
+        Mesh *me_orig = mesh_input;
+        if (me_orig->id.tag & LIB_TAG_COPIED_ON_WRITE) {
+          if (!BKE_mesh_runtime_ensure_edit_data(me_orig)) {
+            BKE_mesh_runtime_reset_edit_data(me_orig);
+          }
+          me_orig->runtime.edit_data->vertexCos = (float(*)[3])MEM_dupallocN(deformed_verts);
+        }
+        mesh_cage = BKE_mesh_wrapper_from_editmesh_with_coords(
+            em_input,
+            &final_datamask,
+            deformed_verts ? (float(*)[3])MEM_dupallocN(deformed_verts) : nullptr,
+            mesh_input);
+      }
+    }
+
+    isPrevDeform = (mti->type == eModifierTypeType_OnlyDeform);
+  }
+
+  BLI_linklist_free((LinkNode *)datamasks, nullptr);
+
+  /* Yay, we are done. If we have a DerivedMesh and deformed vertices need
+   * to apply these back onto the DerivedMesh. If we have no DerivedMesh
+   * then we need to build one. */
+  if (mesh_final) {
+    if (deformed_verts) {
+      Mesh *mesh_tmp = BKE_mesh_copy_for_eval(mesh_final, false);
+      if (mesh_final != mesh_cage) {
+        BKE_id_free(nullptr, mesh_final);
+      }
+      mesh_final = mesh_tmp;
+      BKE_mesh_vert_coords_apply(mesh_final, deformed_verts);
+    }
+  }
+  else if (!deformed_verts && mesh_cage) {
+    /* cage should already have up to date normals */
+    mesh_final = mesh_cage;
+  }
+  else {
+    /* this is just a copy of the editmesh, no need to calc normals */
+    mesh_final = BKE_mesh_wrapper_from_editmesh_with_coords(
+        em_input, &final_datamask, deformed_verts, mesh_input);
+    deformed_verts = nullptr;
+  }
+
+  if (deformed_verts) {
+    MEM_freeN(deformed_verts);
+  }
+
+  /* Add orco coordinates to final and deformed mesh if requested. */
+  if (final_datamask.vmask & CD_MASK_ORCO) {
+    /* FIXME(Campbell): avoid the need to convert to mesh data just to add an orco layer. */
+    BKE_mesh_wrapper_ensure_mdata(mesh_final);
+
+    add_orco_mesh(ob, em_input, mesh_final, mesh_orco, CD_ORCO);
+  }
+
+  if (mesh_orco) {
+    BKE_id_free(nullptr, mesh_orco);
+  }
+
+  /* Ensure normals calculation below is correct. */
+  BLI_assert((mesh_input->flag & ME_AUTOSMOOTH) == (mesh_final->flag & ME_AUTOSMOOTH));
+  BLI_assert(mesh_input->smoothresh == mesh_final->smoothresh);
+  BLI_assert(mesh_input->smoothresh == mesh_cage->smoothresh);
+
+  /* Compute normals. */
+  editbmesh_calc_modifier_final_normals(mesh_final, &final_datamask);
+  if (mesh_cage && (mesh_cage != mesh_final)) {
+    editbmesh_calc_modifier_final_normals(mesh_cage, &final_datamask);
+  }
+
+  /* Return final mesh. */
+  *r_final = mesh_final;
+  if (r_cage) {
+    *r_cage = mesh_cage;
+  }
+}
+
+static void mesh_build_extra_data(struct Depsgraph *depsgraph, Object *ob, Mesh *mesh_eval)
+{
+  uint32_t eval_flags = DEG_get_eval_flags_for_id(depsgraph, &ob->id);
+
+  if (eval_flags & DAG_EVAL_NEED_SHRINKWRAP_BOUNDARY) {
+    BKE_shrinkwrap_compute_boundary_data(mesh_eval);
+  }
+}
+
+static void mesh_runtime_check_normals_valid(const Mesh *mesh)
+{
+  UNUSED_VARS_NDEBUG(mesh);
+  BLI_assert(!(mesh->runtime.cd_dirty_vert & CD_MASK_NORMAL));
+  BLI_assert(!(mesh->runtime.cd_dirty_loop & CD_MASK_NORMAL));
+  BLI_assert(!(mesh->runtime.cd_dirty_poly & CD_MASK_NORMAL));
+}
+
+static void mesh_build_data(struct Depsgraph *depsgraph,
+                            Scene *scene,
+                            Object *ob,
+                            const CustomData_MeshMasks *dataMask,
+                            const bool need_mapping)
+{
+  BLI_assert(ob->type == OB_MESH);
+
+  /* Evaluated meshes aren't supposed to be created on original instances. If you do,
+   * they aren't cleaned up properly on mode switch, causing crashes, e.g T58150. */
+  BLI_assert(ob->id.tag & LIB_TAG_COPIED_ON_WRITE);
+
+  BKE_object_free_derived_caches(ob);
+  if (DEG_is_active(depsgraph)) {
+    BKE_sculpt_update_object_before_eval(ob);
+  }
+
+#if 0 /* XXX This is already taken care of in mesh_calc_modifiers()... */
+  if (need_mapping) {
+    /* Also add the flag so that it is recorded in lastDataMask. */
+    dataMask->vmask |= CD_MASK_ORIGINDEX;
+    dataMask->emask |= CD_MASK_ORIGINDEX;
+    dataMask->pmask |= CD_MASK_ORIGINDEX;
+  }
+#endif
+
+  Mesh *mesh_eval = nullptr, *mesh_deform_eval = nullptr;
+  mesh_calc_modifiers(depsgraph,
+                      scene,
+                      ob,
+                      1,
+                      need_mapping,
+                      dataMask,
+                      -1,
+                      true,
+                      true,
+                      &mesh_deform_eval,
+                      &mesh_eval);
+
+  /* The modifier stack evaluation is storing result in mesh->runtime.mesh_eval, but this result
+   * is not guaranteed to be owned by object.
+   *
+   * Check ownership now, since later on we can not go to a mesh owned by someone else via
+   * object's runtime: this could cause access freed data on depsgraph destruction (mesh who owns
+   * the final result might be freed prior to object). */
+  Mesh *mesh = (Mesh *)ob->data;
+  const bool is_mesh_eval_owned = (mesh_eval != mesh->runtime.mesh_eval);
+  BKE_object_eval_assign_data(ob, &mesh_eval->id, is_mesh_eval_owned);
+
+  ob->runtime.mesh_deform_eval = mesh_deform_eval;
+  ob->runtime.last_data_mask = *dataMask;
+  ob->runtime.last_need_mapping = need_mapping;
+
+  BKE_object_boundbox_calc_from_mesh(ob, mesh_eval);
+
+  /* Make sure that drivers can target shapekey properties.
+   * Note that this causes a potential inconsistency, as the shapekey may have a
+   * different topology than the evaluated mesh. */
+  BLI_assert(mesh->key == nullptr || DEG_is_evaluated_id(&mesh->key->id));
+  mesh_eval->key = mesh->key;
+
+  if ((ob->mode & OB_MODE_ALL_SCULPT) && ob->sculpt) {
+    if (DEG_is_active(depsgraph)) {
+      BKE_sculpt_update_object_after_eval(depsgraph, ob);
+    }
+  }
+
+  mesh_runtime_check_normals_valid(mesh_eval);
+  mesh_build_extra_data(depsgraph, ob, mesh_eval);
+}
+
+static void editbmesh_build_data(struct Depsgraph *depsgraph,
+                                 Scene *scene,
+                                 Object *obedit,
+                                 BMEditMesh *em,
+                                 CustomData_MeshMasks *dataMask)
+{
+  BLI_assert(obedit->id.tag & LIB_TAG_COPIED_ON_WRITE);
+
+  BKE_object_free_derived_caches(obedit);
+  if (DEG_is_active(depsgraph)) {
+    BKE_sculpt_update_object_before_eval(obedit);
+  }
+
+  BKE_editmesh_free_derivedmesh(em);
+
+  Mesh *me_cage;
+  Mesh *me_final;
+
+  editbmesh_calc_modifiers(depsgraph, scene, obedit, em, dataMask, &me_cage, &me_final);
+
+  em->mesh_eval_final = me_final;
+  em->mesh_eval_cage = me_cage;
+
+  BKE_object_boundbox_calc_from_mesh(obedit, em->mesh_eval_final);
+
+  em->lastDataMask = *dataMask;
+
+  mesh_runtime_check_normals_valid(em->mesh_eval_final);
+}
+
+static void object_get_datamask(const Depsgraph *depsgraph,
+                                Object *ob,
+                                CustomData_MeshMasks *r_mask,
+                                bool *r_need_mapping)
+{
+  ViewLayer *view_layer = DEG_get_evaluated_view_layer(depsgraph);
+
+  DEG_get_customdata_mask_for_object(depsgraph, ob, r_mask);
+
+  if (r_need_mapping) {
+    *r_need_mapping = false;
+  }
+
+  /* Must never access original objects when dependency graph is not active: it might be already
+   * freed. */
+  if (!DEG_is_active(depsgraph)) {
+    return;
+  }
+
+  Object *actob = view_layer->basact ? DEG_get_original_object(view_layer->basact->object) :
+                                       nullptr;
+  if (DEG_get_original_object(ob) == actob) {
+    bool editing = BKE_paint_select_face_test(actob);
+
+    /* weight paint and face select need original indices because of selection buffer drawing */
+    if (r_need_mapping) {
+      *r_need_mapping = (editing || (ob->mode & (OB_MODE_WEIGHT_PAINT | OB_MODE_VERTEX_PAINT)));
+    }
+
+    /* check if we need tfaces & mcols due to face select or texture paint */
+    if ((ob->mode & OB_MODE_TEXTURE_PAINT) || editing) {
+      r_mask->lmask |= CD_MASK_MLOOPUV | CD_MASK_MLOOPCOL;
+      r_mask->fmask |= CD_MASK_MTFACE;
+    }
+
+    /* check if we need mcols due to vertex paint or weightpaint */
+    if (ob->mode & OB_MODE_VERTEX_PAINT) {
+      r_mask->lmask |= CD_MASK_MLOOPCOL;
+    }
+
+    if (ob->mode & OB_MODE_WEIGHT_PAINT) {
+      r_mask->vmask |= CD_MASK_MDEFORMVERT;
+    }
+
+    if (ob->mode & OB_MODE_EDIT) {
+      r_mask->vmask |= CD_MASK_MVERT_SKIN;
+    }
+  }
+}
+
+void makeDerivedMesh(struct Depsgraph *depsgraph,
+                     Scene *scene,
+                     Object *ob,
+                     BMEditMesh *em,
+                     const CustomData_MeshMasks *dataMask)
+{
+  bool need_mapping;
+  CustomData_MeshMasks cddata_masks = *dataMask;
+  object_get_datamask(depsgraph, ob, &cddata_masks, &need_mapping);
+
+  if (em) {
+    editbmesh_build_data(depsgraph, scene, ob, em, &cddata_masks);
+  }
+  else {
+    mesh_build_data(depsgraph, scene, ob, &cddata_masks, need_mapping);
+  }
+}
+
+/***/
+
+Mesh *mesh_get_eval_final(struct Depsgraph *depsgraph,
+                          Scene *scene,
+                          Object *ob,
+                          const CustomData_MeshMasks *dataMask)
+{
+  /* This function isn't thread-safe and can't be used during evaluation. */
+  BLI_assert(DEG_is_evaluating(depsgraph) == false);
+
+  /* Evaluated meshes aren't supposed to be created on original instances. If you do,
+   * they aren't cleaned up properly on mode switch, causing crashes, e.g T58150. */
+  BLI_assert(ob->id.tag & LIB_TAG_COPIED_ON_WRITE);
+
+  /* if there's no evaluated mesh or the last data mask used doesn't include
+   * the data we need, rebuild the derived mesh
+   */
+  bool need_mapping;
+  CustomData_MeshMasks cddata_masks = *dataMask;
+  object_get_datamask(depsgraph, ob, &cddata_masks, &need_mapping);
+
+  Mesh *mesh_eval = BKE_object_get_evaluated_mesh(ob);
+  if ((mesh_eval == nullptr) ||
+      !CustomData_MeshMasks_are_matching(&(ob->runtime.last_data_mask), &cddata_masks) ||
+      (need_mapping && !ob->runtime.last_need_mapping)) {
+    CustomData_MeshMasks_update(&cddata_masks, &ob->runtime.last_data_mask);
+    mesh_build_data(
+        depsgraph, scene, ob, &cddata_masks, need_mapping || ob->runtime.last_need_mapping);
+    mesh_eval = BKE_object_get_evaluated_mesh(ob);
+  }
+
+  if (mesh_eval != nullptr) {
+    BLI_assert(!(mesh_eval->runtime.cd_dirty_vert & CD_MASK_NORMAL));
+  }
+  return mesh_eval;
+}
+
+Mesh *mesh_get_eval_deform(struct Depsgraph *depsgraph,
+                           Scene *scene,
+                           Object *ob,
+                           const CustomData_MeshMasks *dataMask)
+{
+  /* This function isn't thread-safe and can't be used during evaluation. */
+  BLI_assert(DEG_is_evaluating(depsgraph) == false);
+
+  /* Evaluated meshes aren't supposed to be created on original instances. If you do,
+   * they aren't cleaned up properly on mode switch, causing crashes, e.g T58150. */
+  BLI_assert(ob->id.tag & LIB_TAG_COPIED_ON_WRITE);
+
+  /* if there's no derived mesh or the last data mask used doesn't include
+   * the data we need, rebuild the derived mesh
+   */
+  bool need_mapping;
+
+  CustomData_MeshMasks cddata_masks = *dataMask;
+  object_get_datamask(depsgraph, ob, &cddata_masks, &need_mapping);
+
+  if (!ob->runtime.mesh_deform_eval ||
+      !CustomData_MeshMasks_are_matching(&(ob->runtime.last_data_mask), &cddata_masks) ||
+      (need_mapping && !ob->runtime.last_need_mapping)) {
+    CustomData_MeshMasks_update(&cddata_masks, &ob->runtime.last_data_mask);
+    mesh_build_data(
+        depsgraph, scene, ob, &cddata_masks, need_mapping || ob->runtime.last_need_mapping);
+  }
+
+  return ob->runtime.mesh_deform_eval;
+}
+
+Mesh *mesh_create_eval_final(Depsgraph *depsgraph,
+                             Scene *scene,
+                             Object *ob,
+                             const CustomData_MeshMasks *dataMask)
+{
+  Mesh *final;
+
+  mesh_calc_modifiers(depsgraph, scene, ob, 1, false, dataMask, -1, false, false, nullptr, &final);
+
+  return final;
+}
+
+Mesh *mesh_create_eval_final_index_render(Depsgraph *depsgraph,
+                                          Scene *scene,
+                                          Object *ob,
+                                          const CustomData_MeshMasks *dataMask,
+                                          int index)
+{
+  Mesh *final;
+
+  mesh_calc_modifiers(
+      depsgraph, scene, ob, 1, false, dataMask, index, false, false, nullptr, &final);
+
+  return final;
+}
+
+Mesh *mesh_create_eval_no_deform(Depsgraph *depsgraph,
+                                 Scene *scene,
+                                 Object *ob,
+                                 const CustomData_MeshMasks *dataMask)
+{
+  Mesh *final;
+
+  mesh_calc_modifiers(depsgraph, scene, ob, 0, false, dataMask, -1, false, false, nullptr, &final);
+
+  return final;
+}
+
+Mesh *mesh_create_eval_no_deform_render(Depsgraph *depsgraph,
+                                        Scene *scene,
+                                        Object *ob,
+                                        const CustomData_MeshMasks *dataMask)
+{
+  Mesh *final;
+
+  mesh_calc_modifiers(depsgraph, scene, ob, 0, false, dataMask, -1, false, false, nullptr, &final);
+
+  return final;
+}
+
+/***/
+
+Mesh *editbmesh_get_eval_cage_and_final(Depsgraph *depsgraph,
+                                        Scene *scene,
+                                        Object *obedit,
+                                        BMEditMesh *em,
+                                        const CustomData_MeshMasks *dataMask,
+                                        /* return args */
+                                        Mesh **r_final)
+{
+  CustomData_MeshMasks cddata_masks = *dataMask;
+
+  /* if there's no derived mesh or the last data mask used doesn't include
+   * the data we need, rebuild the derived mesh
+   */
+  object_get_datamask(depsgraph, obedit, &cddata_masks, nullptr);
+
+  if (!em->mesh_eval_cage ||
+      !CustomData_MeshMasks_are_matching(&(em->lastDataMask), &cddata_masks)) {
+    editbmesh_build_data(depsgraph, scene, obedit, em, &cddata_masks);
+  }
+
+  *r_final = em->mesh_eval_final;
+  if (em->mesh_eval_final) {
+    BLI_assert(!(em->mesh_eval_final->runtime.cd_dirty_vert & DM_DIRTY_NORMALS));
+  }
+  return em->mesh_eval_cage;
+}
+
+Mesh *editbmesh_get_eval_cage(struct Depsgraph *depsgraph,
+                              Scene *scene,
+                              Object *obedit,
+                              BMEditMesh *em,
+                              const CustomData_MeshMasks *dataMask)
+{
+  CustomData_MeshMasks cddata_masks = *dataMask;
+
+  /* if there's no derived mesh or the last data mask used doesn't include
+   * the data we need, rebuild the derived mesh
+   */
+  object_get_datamask(depsgraph, obedit, &cddata_masks, nullptr);
+
+  if (!em->mesh_eval_cage ||
+      !CustomData_MeshMasks_are_matching(&(em->lastDataMask), &cddata_masks)) {
+    editbmesh_build_data(depsgraph, scene, obedit, em, &cddata_masks);
+  }
+
+  return em->mesh_eval_cage;
+}
+
+Mesh *editbmesh_get_eval_cage_from_orig(struct Depsgraph *depsgraph,
+                                        Scene *scene,
+                                        Object *obedit,
+                                        const CustomData_MeshMasks *dataMask)
+{
+  BLI_assert((obedit->id.tag & LIB_TAG_COPIED_ON_WRITE) == 0);
+  Scene *scene_eval = (Scene *)DEG_get_evaluated_id(depsgraph, &scene->id);
+  Object *obedit_eval = (Object *)DEG_get_evaluated_id(depsgraph, &obedit->id);
+  BMEditMesh *em_eval = BKE_editmesh_from_object(obedit_eval);
+  return editbmesh_get_eval_cage(depsgraph, scene_eval, obedit_eval, em_eval, dataMask);
+}
+
+/***/
+
+/* same as above but for vert coords */
+struct MappedUserData {
+  float (*vertexcos)[3];
+  BLI_bitmap *vertex_visit;
+};
+
+static void make_vertexcos__mapFunc(void *userData,
+                                    int index,
+                                    const float co[3],
+                                    const float UNUSED(no_f[3]),
+                                    const short UNUSED(no_s[3]))
+{
+  MappedUserData *mappedData = (MappedUserData *)userData;
+
+  if (BLI_BITMAP_TEST(mappedData->vertex_visit, index) == 0) {
+    /* we need coord from prototype vertex, not from copies,
+     * assume they stored in the beginning of vertex array stored in DM
+     * (mirror modifier for eg does this) */
+    copy_v3_v3(mappedData->vertexcos[index], co);
+    BLI_BITMAP_ENABLE(mappedData->vertex_visit, index);
+  }
+}
+
+void mesh_get_mapped_verts_coords(Mesh *me_eval, float (*r_cos)[3], const int totcos)
+{
+  if (me_eval->runtime.deformed_only == false) {
+    MappedUserData userData;
+    memset(r_cos, 0, sizeof(*r_cos) * totcos);
+    userData.vertexcos = r_cos;
+    userData.vertex_visit = BLI_BITMAP_NEW(totcos, "vertexcos flags");
+    BKE_mesh_foreach_mapped_vert(me_eval, make_vertexcos__mapFunc, &userData, MESH_FOREACH_NOP);
+    MEM_freeN(userData.vertex_visit);
+  }
+  else {
+    MVert *mv = me_eval->mvert;
+    for (int i = 0; i < totcos; i++, mv++) {
+      copy_v3_v3(r_cos[i], mv->co);
+    }
+  }
+}
+
+void DM_calc_loop_tangents(DerivedMesh *dm,
+                           bool calc_active_tangent,
+                           const char (*tangent_names)[MAX_NAME],
+                           int tangent_names_len)
+{
+  BKE_mesh_calc_loop_tangent_ex(
+      dm->getVertArray(dm),
+      dm->getPolyArray(dm),
+      dm->getNumPolys(dm),
+      dm->getLoopArray(dm),
+      dm->getLoopTriArray(dm),
+      dm->getNumLoopTri(dm),
+      &dm->loopData,
+      calc_active_tangent,
+      tangent_names,
+      tangent_names_len,
+      (float(*)[3])CustomData_get_layer(&dm->polyData, CD_NORMAL),
+      (float(*)[3])dm->getLoopDataArray(dm, CD_NORMAL),
+      (float(*)[3])dm->getVertDataArray(dm, CD_ORCO), /* may be nullptr */
+      /* result */
+      &dm->loopData,
+      dm->getNumLoops(dm),
+      &dm->tangent_mask);
+}
+
+static void mesh_init_origspace(Mesh *mesh)
+{
+  const float default_osf[4][2] = {{0, 0}, {1, 0}, {1, 1}, {0, 1}};
+
+  OrigSpaceLoop *lof_array = (OrigSpaceLoop *)CustomData_get_layer(&mesh->ldata,
+                                                                   CD_ORIGSPACE_MLOOP);
+  const int numpoly = mesh->totpoly;
+  // const int numloop = mesh->totloop;
+  MVert *mv = mesh->mvert;
+  MLoop *ml = mesh->mloop;
+  MPoly *mp = mesh->mpoly;
+  int i, j, k;
+
+  blender::Vector<blender::float2, 64> vcos_2d;
+
+  for (i = 0; i < numpoly; i++, mp++) {
+    OrigSpaceLoop *lof = lof_array + mp->loopstart;
+
+    if (ELEM(mp->totloop, 3, 4)) {
+      for (j = 0; j < mp->totloop; j++, lof++) {
+        copy_v2_v2(lof->uv, default_osf[j]);
+      }
+    }
+    else {
+      MLoop *l = &ml[mp->loopstart];
+      float p_nor[3], co[3];
+      float mat[3][3];
+
+      float min[2] = {FLT_MAX, FLT_MAX}, max[2] = {-FLT_MAX, -FLT_MAX};
+      float translate[2], scale[2];
+
+      BKE_mesh_calc_poly_normal(mp, l, mv, p_nor);
+      axis_dominant_v3_to_m3(mat, p_nor);
+
+      vcos_2d.resize(mp->totloop);
+      for (j = 0; j < mp->totloop; j++, l++) {
+        mul_v3_m3v3(co, mat, mv[l->v].co);
+        copy_v2_v2(vcos_2d[j], co);
+
+        for (k = 0; k < 2; k++) {
+          if (co[k] > max[k]) {
+            max[k] = co[k];
+          }
+          else if (co[k] < min[k]) {
+            min[k] = co[k];
+          }
+        }
+      }
+
+      /* Brings min to (0, 0). */
+      negate_v2_v2(translate, min);
+
+      /* Scale will bring max to (1, 1). */
+      sub_v2_v2v2(scale, max, min);
+      if (scale[0] == 0.0f) {
+        scale[0] = 1e-9f;
+      }
+      if (scale[1] == 0.0f) {
+        scale[1] = 1e-9f;
+      }
+      invert_v2(scale);
+
+      /* Finally, transform all vcos_2d into ((0, 0), (1, 1))
+       * square and assign them as origspace. */
+      for (j = 0; j < mp->totloop; j++, lof++) {
+        add_v2_v2v2(lof->uv, vcos_2d[j], translate);
+        mul_v2_v2(lof->uv, scale);
+      }
+    }
+  }
+
+  BKE_mesh_tessface_clear(mesh);
+}
+
+/* derivedmesh info printing function,
+ * to help track down differences DM output */
+
+#ifndef NDEBUG
+#  include "BLI_dynstr.h"
+
+static void dm_debug_info_layers(DynStr *dynstr,
+                                 DerivedMesh *dm,
+                                 CustomData *cd,
+                                 void *(*getElemDataArray)(DerivedMesh *, int))
+{
+  int type;
+
+  for (type = 0; type < CD_NUMTYPES; type++) {
+    if (CustomData_has_layer(cd, type)) {
+      /* note: doesn't account for multiple layers */
+      const char *name = CustomData_layertype_name(type);
+      const int size = CustomData_sizeof(type);
+      const void *pt = getElemDataArray(dm, type);
+      const int pt_size = pt ? (int)(MEM_allocN_len(pt) / size) : 0;
+      const char *structname;
+      int structnum;
+      CustomData_file_write_info(type, &structname, &structnum);
+      BLI_dynstr_appendf(
+          dynstr,
+          "        dict(name='%s', struct='%s', type=%d, ptr='%p', elem=%d, length=%d),\n",
+          name,
+          structname,
+          type,
+          (const void *)pt,
+          size,
+          pt_size);
+    }
+  }
+}
+
+char *DM_debug_info(DerivedMesh *dm)
+{
+  DynStr *dynstr = BLI_dynstr_new();
+  char *ret;
+  const char *tstr;
+
+  BLI_dynstr_append(dynstr, "{\n");
+  BLI_dynstr_appendf(dynstr, "    'ptr': '%p',\n", (void *)dm);
+  switch (dm->type) {
+    case DM_TYPE_CDDM:
+      tstr = "DM_TYPE_CDDM";
+      break;
+    case DM_TYPE_CCGDM:
+      tstr = "DM_TYPE_CCGDM";
+      break;
+    default:
+      tstr = "UNKNOWN";
+      break;
+  }
+  BLI_dynstr_appendf(dynstr, "    'type': '%s',\n", tstr);
+  BLI_dynstr_appendf(dynstr, "    'numVertData': %d,\n", dm->numVertData);
+  BLI_dynstr_appendf(dynstr, "    'numEdgeData': %d,\n", dm->numEdgeData);
+  BLI_dynstr_appendf(dynstr, "    'numTessFaceData': %d,\n", dm->numTessFaceData);
+  BLI_dynstr_appendf(dynstr, "    'numPolyData': %d,\n", dm->numPolyData);
+  BLI_dynstr_appendf(dynstr, "    'deformedOnly': %d,\n", dm->deformedOnly);
+
+  BLI_dynstr_append(dynstr, "    'vertexLayers': (\n");
+  dm_debug_info_layers(dynstr, dm, &dm->vertData, dm->getVertDataArray);
+  BLI_dynstr_append(dynstr, "    ),\n");
+
+  BLI_dynstr_append(dynstr, "    'edgeLayers': (\n");
+  dm_debug_info_layers(dynstr, dm, &dm->edgeData, dm->getEdgeDataArray);
+  BLI_dynstr_append(dynstr, "    ),\n");
+
+  BLI_dynstr_append(dynstr, "    'loopLayers': (\n");
+  dm_debug_info_layers(dynstr, dm, &dm->loopData, dm->getLoopDataArray);
+  BLI_dynstr_append(dynstr, "    ),\n");
+
+  BLI_dynstr_append(dynstr, "    'polyLayers': (\n");
+  dm_debug_info_layers(dynstr, dm, &dm->polyData, dm->getPolyDataArray);
+  BLI_dynstr_append(dynstr, "    ),\n");
+
+  BLI_dynstr_append(dynstr, "    'tessFaceLayers': (\n");
+  dm_debug_info_layers(dynstr, dm, &dm->faceData, dm->getTessFaceDataArray);
+  BLI_dynstr_append(dynstr, "    ),\n");
+
+  BLI_dynstr_append(dynstr, "}\n");
+
+  ret = BLI_dynstr_get_cstring(dynstr);
+  BLI_dynstr_free(dynstr);
+  return ret;
+}
+
+void DM_debug_print(DerivedMesh *dm)
+{
+  char *str = DM_debug_info(dm);
+  puts(str);
+  fflush(stdout);
+  MEM_freeN(str);
+}
+
+bool DM_is_valid(DerivedMesh *dm)
+{
+  const bool do_verbose = true;
+  const bool do_fixes = false;
+
+  bool is_valid = true;
+  bool changed = true;
+
+  is_valid &= BKE_mesh_validate_all_customdata(
+      dm->getVertDataLayout(dm),
+      dm->getNumVerts(dm),
+      dm->getEdgeDataLayout(dm),
+      dm->getNumEdges(dm),
+      dm->getLoopDataLayout(dm),
+      dm->getNumLoops(dm),
+      dm->getPolyDataLayout(dm),
+      dm->getNumPolys(dm),
+      false, /* setting mask here isn't useful, gives false positives */
+      do_verbose,
+      do_fixes,
+      &changed);
+
+  is_valid &= BKE_mesh_validate_arrays(nullptr,
+                                       dm->getVertArray(dm),
+                                       dm->getNumVerts(dm),
+                                       dm->getEdgeArray(dm),
+                                       dm->getNumEdges(dm),
+                                       dm->getTessFaceArray(dm),
+                                       dm->getNumTessFaces(dm),
+                                       dm->getLoopArray(dm),
+                                       dm->getNumLoops(dm),
+                                       dm->getPolyArray(dm),
+                                       dm->getNumPolys(dm),
+                                       (MDeformVert *)dm->getVertDataArray(dm, CD_MDEFORMVERT),
+                                       do_verbose,
+                                       do_fixes,
+                                       &changed);
+
+  BLI_assert(changed == false);
+
+  return is_valid;
+}
+
+#endif /* NDEBUG */