Cleanup: Use const when retrieving custom data layers

Knowing when layers are retrieved for write access will be essential
when adding proper copy-on-write support. This commit makes that
clearer by adding `const` where the retrieved data is not modified.

Ref T95842

50 files changed, 188 insertions, 200 deletions

diff --git a/source/blender/blenkernel/BKE_deform.h b/source/blender/blenkernel/BKE_deform.h
index 1b225884b14..d32f754c6c0 100644
--- a/source/blender/blenkernel/BKE_deform.h
+++ b/source/blender/blenkernel/BKE_deform.h
@@ -228,35 +228,38 @@ void BKE_defvert_normalize_lock_map(struct MDeformVert *dvert,
 /* Utilities to 'extract' a given vgroup into a simple float array,
  * for verts, but also edges/polys/loops. */
 
-void BKE_defvert_extract_vgroup_to_vertweights(
-    struct MDeformVert *dvert, int defgroup, int num_verts, float *r_weights, bool invert_vgroup);
+void BKE_defvert_extract_vgroup_to_vertweights(const struct MDeformVert *dvert,
+                                               int defgroup,
+                                               int num_verts,
+                                               bool invert_vgroup,
+                                               float *r_weights);
 /**
  * The following three make basic interpolation,
  * using temp vert_weights array to avoid looking up same weight several times.
  */
-void BKE_defvert_extract_vgroup_to_edgeweights(struct MDeformVert *dvert,
+void BKE_defvert_extract_vgroup_to_edgeweights(const struct MDeformVert *dvert,
                                                int defgroup,
                                                int num_verts,
                                                struct MEdge *edges,
                                                int num_edges,
-                                               float *r_weights,
-                                               bool invert_vgroup);
-void BKE_defvert_extract_vgroup_to_loopweights(struct MDeformVert *dvert,
+                                               bool invert_vgroup,
+                                               float *r_weights);
+void BKE_defvert_extract_vgroup_to_loopweights(const struct MDeformVert *dvert,
                                                int defgroup,
                                                int num_verts,
                                                struct MLoop *loops,
                                                int num_loops,
-                                               float *r_weights,
-                                               bool invert_vgroup);
-void BKE_defvert_extract_vgroup_to_polyweights(struct MDeformVert *dvert,
+                                               bool invert_vgroup,
+                                               float *r_weights);
+void BKE_defvert_extract_vgroup_to_polyweights(const struct MDeformVert *dvert,
                                                int defgroup,
                                                int num_verts,
                                                struct MLoop *loops,
                                                int num_loops,
                                                struct MPoly *polys,
                                                int num_polys,
-                                               float *r_weights,
-                                               bool invert_vgroup);
+                                               bool invert_vgroup,
+                                               float *r_weights);
 
 void BKE_defvert_weight_to_rgb(float r_rgb[3], float weight);
 
diff --git a/source/blender/blenkernel/BKE_particle.h b/source/blender/blenkernel/BKE_particle.h
index 123fdbb8bac..5f8b2fafdd3 100644
--- a/source/blender/blenkernel/BKE_particle.h
+++ b/source/blender/blenkernel/BKE_particle.h
@@ -583,7 +583,7 @@ void psys_interpolate_face(struct Mesh *mesh,
                            const float (*vert_normals)[3],
                            struct MFace *mface,
                            struct MTFace *tface,
-                           float (*orcodata)[3],
+                           const float (*orcodata)[3],
                            float w[4],
                            float vec[3],
                            float nor[3],
diff --git a/source/blender/blenkernel/BKE_shrinkwrap.h b/source/blender/blenkernel/BKE_shrinkwrap.h
index 2144419728e..3e06bd84805 100644
--- a/source/blender/blenkernel/BKE_shrinkwrap.h
+++ b/source/blender/blenkernel/BKE_shrinkwrap.h
@@ -73,7 +73,7 @@ typedef struct ShrinkwrapTreeData {
   BVHTreeFromMesh treeData;
 
   const float (*pnors)[3];
-  float (*clnors)[3];
+  const float (*clnors)[3];
   ShrinkwrapBoundaryData *boundary;
 } ShrinkwrapTreeData;
 
diff --git a/source/blender/blenkernel/intern/cloth.c b/source/blender/blenkernel/intern/cloth.c
index c33c65be795..8f0c8e4c1c7 100644
--- a/source/blender/blenkernel/intern/cloth.c
+++ b/source/blender/blenkernel/intern/cloth.c
@@ -715,7 +715,7 @@ static bool cloth_from_object(
   int i = 0;
   MVert *mvert = NULL;
   ClothVertex *verts = NULL;
-  float(*shapekey_rest)[3] = NULL;
+  const float(*shapekey_rest)[3] = NULL;
   const float tnull[3] = {0, 0, 0};
 
   /* If we have a clothObject, free it. */
diff --git a/source/blender/blenkernel/intern/data_transfer.c b/source/blender/blenkernel/intern/data_transfer.c
index 6a3f6a47f5e..33e36e47812 100644
--- a/source/blender/blenkernel/intern/data_transfer.c
+++ b/source/blender/blenkernel/intern/data_transfer.c
@@ -477,7 +477,7 @@ static void data_transfer_layersmapping_add_item_cd(ListBase *r_map,
                                                     const int mix_mode,
                                                     const float mix_factor,
                                                     const float *mix_weights,
-                                                    void *data_src,
+                                                    const void *data_src,
                                                     void *data_dst,
                                                     cd_datatransfer_interp interp,
                                                     void *interp_data)
@@ -532,7 +532,8 @@ static bool data_transfer_layersmapping_cdlayers_multisrc_to_dst(ListBase *r_map
                                                                  cd_datatransfer_interp interp,
                                                                  void *interp_data)
 {
-  void *data_src, *data_dst = NULL;
+  const void *data_src;
+  void *data_dst = NULL;
   int idx_src = num_layers_src;
   int idx_dst, tot_dst = CustomData_number_of_layers(cd_dst, cddata_type);
   bool *data_dst_to_delete = NULL;
@@ -695,7 +696,8 @@ static bool data_transfer_layersmapping_cdlayers(ListBase *r_map,
                                                  void *interp_data)
 {
   int idx_src, idx_dst;
-  void *data_src, *data_dst = NULL;
+  const void *data_src;
+  void *data_dst = NULL;
 
   if (CustomData_layertype_is_singleton(cddata_type)) {
     if (!(data_src = CustomData_get_layer(cd_src, cddata_type))) {
@@ -1369,7 +1371,7 @@ bool BKE_object_data_transfer_ex(struct Depsgraph *depsgraph,
   /* Assumed always true if not using an evaluated mesh as destination. */
   bool dirty_nors_dst = true;
 
-  MDeformVert *mdef = NULL;
+  const MDeformVert *mdef = NULL;
   int vg_idx = -1;
   float *weights[DATAMAX] = {NULL};
 
@@ -1509,7 +1511,7 @@ bool BKE_object_data_transfer_ex(struct Depsgraph *depsgraph,
       if (mdef && vg_idx != -1 && !weights[VDATA]) {
         weights[VDATA] = MEM_mallocN(sizeof(*(weights[VDATA])) * (size_t)num_verts_dst, __func__);
         BKE_defvert_extract_vgroup_to_vertweights(
-            mdef, vg_idx, num_verts_dst, weights[VDATA], invert_vgroup);
+            mdef, vg_idx, num_verts_dst, invert_vgroup, weights[VDATA]);
       }
 
       if (data_transfer_layersmapping_generate(&lay_map,
@@ -1588,7 +1590,7 @@ bool BKE_object_data_transfer_ex(struct Depsgraph *depsgraph,
       if (mdef && vg_idx != -1 && !weights[EDATA]) {
         weights[EDATA] = MEM_mallocN(sizeof(*weights[EDATA]) * (size_t)num_edges_dst, __func__);
         BKE_defvert_extract_vgroup_to_edgeweights(
-            mdef, vg_idx, num_verts_dst, edges_dst, num_edges_dst, weights[EDATA], invert_vgroup);
+            mdef, vg_idx, num_verts_dst, edges_dst, num_edges_dst, invert_vgroup, weights[EDATA]);
       }
 
       if (data_transfer_layersmapping_generate(&lay_map,
@@ -1683,7 +1685,7 @@ bool BKE_object_data_transfer_ex(struct Depsgraph *depsgraph,
       if (mdef && vg_idx != -1 && !weights[LDATA]) {
         weights[LDATA] = MEM_mallocN(sizeof(*weights[LDATA]) * (size_t)num_loops_dst, __func__);
         BKE_defvert_extract_vgroup_to_loopweights(
-            mdef, vg_idx, num_verts_dst, loops_dst, num_loops_dst, weights[LDATA], invert_vgroup);
+            mdef, vg_idx, num_verts_dst, loops_dst, num_loops_dst, invert_vgroup, weights[LDATA]);
       }
 
       if (data_transfer_layersmapping_generate(&lay_map,
@@ -1769,8 +1771,8 @@ bool BKE_object_data_transfer_ex(struct Depsgraph *depsgraph,
                                                   num_loops_dst,
                                                   polys_dst,
                                                   num_polys_dst,
-                                                  weights[PDATA],
-                                                  invert_vgroup);
+                                                  invert_vgroup,
+                                                  weights[PDATA]);
       }
 
       if (data_transfer_layersmapping_generate(&lay_map,
diff --git a/source/blender/blenkernel/intern/deform.c b/source/blender/blenkernel/intern/deform.c
index 1d276e9108c..c7ac82e4b68 100644
--- a/source/blender/blenkernel/intern/deform.c
+++ b/source/blender/blenkernel/intern/deform.c
@@ -147,9 +147,9 @@ void BKE_defvert_copy_index(MDeformVert *dvert_dst,
                             const MDeformVert *dvert_src,
                             const int defgroup_src)
 {
-  MDeformWeight *dw_src, *dw_dst;
+  MDeformWeight *dw_dst;
 
-  dw_src = BKE_defvert_find_index(dvert_src, defgroup_src);
+  const MDeformWeight *dw_src = BKE_defvert_find_index(dvert_src, defgroup_src);
 
   if (dw_src) {
     /* Source is valid, ensure destination is created. */
@@ -1008,11 +1008,11 @@ void BKE_defvert_array_free(MDeformVert *dvert, int totvert)
   MEM_freeN(dvert);
 }
 
-void BKE_defvert_extract_vgroup_to_vertweights(MDeformVert *dvert,
+void BKE_defvert_extract_vgroup_to_vertweights(const MDeformVert *dvert,
                                                const int defgroup,
                                                const int num_verts,
-                                               float *r_weights,
-                                               const bool invert_vgroup)
+                                               const bool invert_vgroup,
+                                               float *r_weights)
 {
   if (dvert && defgroup != -1) {
     int i = num_verts;
@@ -1027,20 +1027,20 @@ void BKE_defvert_extract_vgroup_to_vertweights(MDeformVert *dvert,
   }
 }
 
-void BKE_defvert_extract_vgroup_to_edgeweights(MDeformVert *dvert,
+void BKE_defvert_extract_vgroup_to_edgeweights(const MDeformVert *dvert,
                                                const int defgroup,
                                                const int num_verts,
                                                MEdge *edges,
                                                const int num_edges,
-                                               float *r_weights,
-                                               const bool invert_vgroup)
+                                               const bool invert_vgroup,
+                                               float *r_weights)
 {
   if (dvert && defgroup != -1) {
     int i = num_edges;
     float *tmp_weights = MEM_mallocN(sizeof(*tmp_weights) * (size_t)num_verts, __func__);
 
     BKE_defvert_extract_vgroup_to_vertweights(
-        dvert, defgroup, num_verts, tmp_weights, invert_vgroup);
+        dvert, defgroup, num_verts, invert_vgroup, tmp_weights);
 
     while (i--) {
       MEdge *me = &edges[i];
@@ -1055,20 +1055,20 @@ void BKE_defvert_extract_vgroup_to_edgeweights(MDeformVert *dvert,
   }
 }
 
-void BKE_defvert_extract_vgroup_to_loopweights(MDeformVert *dvert,
+void BKE_defvert_extract_vgroup_to_loopweights(const MDeformVert *dvert,
                                                const int defgroup,
                                                const int num_verts,
                                                MLoop *loops,
                                                const int num_loops,
-                                               float *r_weights,
-                                               const bool invert_vgroup)
+                                               const bool invert_vgroup,
+                                               float *r_weights)
 {
   if (dvert && defgroup != -1) {
     int i = num_loops;
     float *tmp_weights = MEM_mallocN(sizeof(*tmp_weights) * (size_t)num_verts, __func__);
 
     BKE_defvert_extract_vgroup_to_vertweights(
-        dvert, defgroup, num_verts, tmp_weights, invert_vgroup);
+        dvert, defgroup, num_verts, invert_vgroup, tmp_weights);
 
     while (i--) {
       MLoop *ml = &loops[i];
@@ -1083,22 +1083,22 @@ void BKE_defvert_extract_vgroup_to_loopweights(MDeformVert *dvert,
   }
 }
 
-void BKE_defvert_extract_vgroup_to_polyweights(MDeformVert *dvert,
+void BKE_defvert_extract_vgroup_to_polyweights(const MDeformVert *dvert,
                                                const int defgroup,
                                                const int num_verts,
                                                MLoop *loops,
                                                const int UNUSED(num_loops),
                                                MPoly *polys,
                                                const int num_polys,
-                                               float *r_weights,
-                                               const bool invert_vgroup)
+                                               const bool invert_vgroup,
+                                               float *r_weights)
 {
   if (dvert && defgroup != -1) {
     int i = num_polys;
     float *tmp_weights = MEM_mallocN(sizeof(*tmp_weights) * (size_t)num_verts, __func__);
 
     BKE_defvert_extract_vgroup_to_vertweights(
-        dvert, defgroup, num_verts, tmp_weights, invert_vgroup);
+        dvert, defgroup, num_verts, invert_vgroup, tmp_weights);
 
     while (i--) {
       MPoly *mp = &polys[i];
@@ -1193,7 +1193,7 @@ static bool data_transfer_layersmapping_vgroups_multisrc_to_dst(ListBase *r_map,
                                                                 const bool use_delete,
                                                                 Object *ob_src,
                                                                 Object *ob_dst,
-                                                                MDeformVert *data_src,
+                                                                const MDeformVert *data_src,
                                                                 MDeformVert *data_dst,
                                                                 CustomData *UNUSED(cd_src),
                                                                 CustomData *cd_dst,
@@ -1348,7 +1348,6 @@ bool data_transfer_layersmapping_vgroups(ListBase *r_map,
                                          const int tolayers)
 {
   int idx_src, idx_dst;
-  MDeformVert *data_src, *data_dst = NULL;
 
   const size_t elem_size = sizeof(*((MDeformVert *)NULL));
 
@@ -1370,9 +1369,9 @@ bool data_transfer_layersmapping_vgroups(ListBase *r_map,
     return true;
   }
 
-  data_src = CustomData_get_layer(cd_src, CD_MDEFORMVERT);
+  const MDeformVert *data_src = CustomData_get_layer(cd_src, CD_MDEFORMVERT);
 
-  data_dst = CustomData_get_layer(cd_dst, CD_MDEFORMVERT);
+  MDeformVert *data_dst = CustomData_get_layer(cd_dst, CD_MDEFORMVERT);
   if (data_dst && use_dupref_dst && r_map) {
     /* If dest is a derivedmesh, we do not want to overwrite cdlayers of org mesh! */
     data_dst = CustomData_duplicate_referenced_layer(cd_dst, CD_MDEFORMVERT, num_elem_dst);
diff --git a/source/blender/blenkernel/intern/fluid.c b/source/blender/blenkernel/intern/fluid.c
index 5de13fbdbed..6c9723dafd1 100644
--- a/source/blender/blenkernel/intern/fluid.c
+++ b/source/blender/blenkernel/intern/fluid.c
@@ -1824,7 +1824,7 @@ static void sample_mesh(FluidFlowSettings *ffs,
                         const float *vert_vel,
                         bool has_velocity,
                         int defgrp_index,
-                        MDeformVert *dvert,
+                        const MDeformVert *dvert,
                         float x,
                         float y,
                         float z)
@@ -2008,7 +2008,7 @@ typedef struct EmitFromDMData {
   const MLoop *mloop;
   const MLoopTri *mlooptri;
   const MLoopUV *mloopuv;
-  MDeformVert *dvert;
+  const MDeformVert *dvert;
   int defgrp_index;
 
   BVHTreeFromMesh *tree;
@@ -2079,7 +2079,7 @@ static void emit_from_mesh(
     const MLoopTri *mlooptri = NULL;
     const MLoop *mloop = NULL;
     const MLoopUV *mloopuv = NULL;
-    MDeformVert *dvert = NULL;
+    const MDeformVert *dvert = NULL;
     BVHTreeFromMesh tree_data = {NULL};
     int numverts, i;
 
diff --git a/source/blender/blenkernel/intern/mesh_remesh_voxel.cc b/source/blender/blenkernel/intern/mesh_remesh_voxel.cc
index 02c9f61957d..c960a7f35f1 100644
--- a/source/blender/blenkernel/intern/mesh_remesh_voxel.cc
+++ b/source/blender/blenkernel/intern/mesh_remesh_voxel.cc
@@ -290,7 +290,7 @@ void BKE_mesh_remesh_reproject_paint_mask(Mesh *target, Mesh *source)
         &target->vdata, CD_PAINT_MASK, CD_CALLOC, nullptr, target->totvert);
   }
 
-  float *source_mask;
+  const float *source_mask;
   if (CustomData_has_layer(&source->vdata, CD_PAINT_MASK)) {
     source_mask = (float *)CustomData_get_layer(&source->vdata, CD_PAINT_MASK);
   }
diff --git a/source/blender/blenkernel/intern/mesh_tangent.c b/source/blender/blenkernel/intern/mesh_tangent.c
index f2e46c3bd92..16d76a75f2c 100644
--- a/source/blender/blenkernel/intern/mesh_tangent.c
+++ b/source/blender/blenkernel/intern/mesh_tangent.c
@@ -155,7 +155,7 @@ void BKE_mesh_calc_loop_tangent_single(Mesh *mesh,
                                        float (*r_looptangents)[4],
                                        ReportList *reports)
 {
-  MLoopUV *loopuvs;
+  const MLoopUV *loopuvs;
   float(*loopnors)[3];
 
   /* Check we have valid texture coordinates first! */
@@ -205,10 +205,10 @@ typedef struct {
   const float (*precomputedFaceNormals)[3];
   const float (*precomputedLoopNormals)[3];
   const MLoopTri *looptri;
-  MLoopUV *mloopuv;   /* texture coordinates */
-  const MPoly *mpoly; /* indices */
-  const MLoop *mloop; /* indices */
-  const MVert *mvert; /* vertex coordinates */
+  const MLoopUV *mloopuv; /* texture coordinates */
+  const MPoly *mpoly;     /* indices */
+  const MLoop *mloop;     /* indices */
+  const MVert *mvert;     /* vertex coordinates */
   const float (*vert_normals)[3];
   const float (*orco)[3];
   float (*tangent)[4]; /* destination */
diff --git a/source/blender/blenkernel/intern/mesh_tessellate.c b/source/blender/blenkernel/intern/mesh_tessellate.c
index ea3cc043267..7cb656d2357 100644
--- a/source/blender/blenkernel/intern/mesh_tessellate.c
+++ b/source/blender/blenkernel/intern/mesh_tessellate.c
@@ -69,7 +69,7 @@ static void mesh_loops_to_tessdata(CustomData *fdata,
 
   for (i = 0; i < numUV; i++) {
     MTFace *texface = CustomData_get_layer_n(fdata, CD_MTFACE, i);
-    MLoopUV *mloopuv = CustomData_get_layer_n(ldata, CD_MLOOPUV, i);
+    const MLoopUV *mloopuv = CustomData_get_layer_n(ldata, CD_MLOOPUV, i);
 
     for (findex = 0, pidx = polyindices, lidx = loopindices; findex < num_faces;
          pidx++, lidx++, findex++, texface++) {
@@ -81,7 +81,7 @@ static void mesh_loops_to_tessdata(CustomData *fdata,
 
   for (i = 0; i < numCol; i++) {
     MCol(*mcol)[4] = CustomData_get_layer_n(fdata, CD_MCOL, i);
-    MLoopCol *mloopcol = CustomData_get_layer_n(ldata, CD_PROP_BYTE_COLOR, i);
+    const MLoopCol *mloopcol = CustomData_get_layer_n(ldata, CD_PROP_BYTE_COLOR, i);
 
     for (findex = 0, lidx = loopindices; findex < num_faces; lidx++, findex++, mcol++) {
       for (j = (mface ? mface[findex].v4 : (*lidx)[3]) ? 4 : 3; j--;) {
@@ -92,7 +92,7 @@ static void mesh_loops_to_tessdata(CustomData *fdata,
 
   if (hasPCol) {
     MCol(*mcol)[4] = CustomData_get_layer(fdata, CD_PREVIEW_MCOL);
-    MLoopCol *mloopcol = CustomData_get_layer(ldata, CD_PREVIEW_MLOOPCOL);
+    const MLoopCol *mloopcol = CustomData_get_layer(ldata, CD_PREVIEW_MLOOPCOL);
 
     for (findex = 0, lidx = loopindices; findex < num_faces; lidx++, findex++, mcol++) {
       for (j = (mface ? mface[findex].v4 : (*lidx)[3]) ? 4 : 3; j--;) {
@@ -103,7 +103,7 @@ static void mesh_loops_to_tessdata(CustomData *fdata,
 
   if (hasOrigSpace) {
     OrigSpaceFace *of = CustomData_get_layer(fdata, CD_ORIGSPACE);
-    OrigSpaceLoop *lof = CustomData_get_layer(ldata, CD_ORIGSPACE_MLOOP);
+    const OrigSpaceLoop *lof = CustomData_get_layer(ldata, CD_ORIGSPACE_MLOOP);
 
     for (findex = 0, lidx = loopindices; findex < num_faces; lidx++, findex++, of++) {
       for (j = (mface ? mface[findex].v4 : (*lidx)[3]) ? 4 : 3; j--;) {
@@ -114,7 +114,7 @@ static void mesh_loops_to_tessdata(CustomData *fdata,
 
   if (hasLoopNormal) {
     short(*fnors)[4][3] = CustomData_get_layer(fdata, CD_TESSLOOPNORMAL);
-    float(*lnors)[3] = CustomData_get_layer(ldata, CD_NORMAL);
+    const float(*lnors)[3] = CustomData_get_layer(ldata, CD_NORMAL);
 
     for (findex = 0, lidx = loopindices; findex < num_faces; lidx++, findex++, fnors++) {
       for (j = (mface ? mface[findex].v4 : (*lidx)[3]) ? 4 : 3; j--;) {
@@ -126,7 +126,7 @@ static void mesh_loops_to_tessdata(CustomData *fdata,
   if (hasLoopTangent) {
     /* Need to do for all UV maps at some point. */
     float(*ftangents)[4] = CustomData_get_layer(fdata, CD_TANGENT);
-    float(*ltangents)[4] = CustomData_get_layer(ldata, CD_TANGENT);
+    const float(*ltangents)[4] = CustomData_get_layer(ldata, CD_TANGENT);
 
     for (findex = 0, pidx = polyindices, lidx = loopindices; findex < num_faces;
          pidx++, lidx++, findex++) {
@@ -154,8 +154,8 @@ int BKE_mesh_tessface_calc_ex(CustomData *fdata,
 
   const int looptri_num = poly_to_tri_count(totpoly, totloop);
 
-  MPoly *mp, *mpoly;
-  MLoop *ml, *mloop;
+  const MPoly *mp, *mpoly;
+  const MLoop *ml, *mloop;
   MFace *mface, *mf;
   MemArena *arena = NULL;
   int *mface_to_poly_map;
diff --git a/source/blender/blenkernel/intern/multires.c b/source/blender/blenkernel/intern/multires.c
index b0e235662cb..4f4e794462b 100644
--- a/source/blender/blenkernel/intern/multires.c
+++ b/source/blender/blenkernel/intern/multires.c
@@ -1021,7 +1021,7 @@ void multires_modifier_update_mdisps(struct DerivedMesh *dm, Scene *scene)
   CCGDerivedMesh *ccgdm = (CCGDerivedMesh *)dm;
   Object *ob;
   Mesh *me;
-  MDisps *mdisps;
+  const MDisps *mdisps;
   MultiresModifierData *mmd;
 
   ob = ccgdm->multires.ob;
diff --git a/source/blender/blenkernel/intern/paint.c b/source/blender/blenkernel/intern/paint.c
index 0f523d87d9b..caada8da0de 100644
--- a/source/blender/blenkernel/intern/paint.c
+++ b/source/blender/blenkernel/intern/paint.c
@@ -2051,7 +2051,7 @@ void BKE_sculpt_face_sets_ensure_from_base_mesh_visibility(Mesh *mesh)
 
 void BKE_sculpt_sync_face_sets_visibility_to_base_mesh(Mesh *mesh)
 {
-  int *face_sets = CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS);
+  const int *face_sets = CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS);
   if (!face_sets) {
     return;
   }
@@ -2066,7 +2066,7 @@ void BKE_sculpt_sync_face_sets_visibility_to_base_mesh(Mesh *mesh)
 
 void BKE_sculpt_sync_face_sets_visibility_to_grids(Mesh *mesh, SubdivCCG *subdiv_ccg)
 {
-  int *face_sets = CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS);
+  const int *face_sets = CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS);
   if (!face_sets) {
     return;
   }
diff --git a/source/blender/blenkernel/intern/particle.c b/source/blender/blenkernel/intern/particle.c
index 72d9f72eb14..a594453bee9 100644
--- a/source/blender/blenkernel/intern/particle.c
+++ b/source/blender/blenkernel/intern/particle.c
@@ -1667,7 +1667,7 @@ void psys_interpolate_face(Mesh *mesh,
                            const float (*vert_normals)[3],
                            MFace *mface,
                            MTFace *tface,
-                           float (*orcodata)[3],
+                           const float (*orcodata)[3],
                            float w[4],
                            float vec[3],
                            float nor[3],
@@ -1680,7 +1680,7 @@ void psys_interpolate_face(Mesh *mesh,
   float *uv1, *uv2, *uv3, *uv4;
   float n1[3], n2[3], n3[3], n4[3];
   float tuv[4][2];
-  float *o1, *o2, *o3, *o4;
+  const float *o1, *o2, *o3, *o4;
 
   v1 = mvert[mface->v1].co;
   v2 = mvert[mface->v2].co;
@@ -1903,9 +1903,10 @@ int psys_particle_dm_face_lookup(Mesh *mesh_final,
                                  struct LinkNode **poly_nodes)
 {
   MFace *mtessface_final;
-  OrigSpaceFace *osface_final;
+  const OrigSpaceFace *osface_final;
   int pindex_orig;
-  float uv[2], (*faceuv)[2];
+  float uv[2];
+  const float(*faceuv)[2];
 
   const int *index_mf_to_mpoly_deformed = NULL;
   const int *index_mf_to_mpoly = NULL;
@@ -2048,11 +2049,7 @@ static int psys_map_index_on_dm(Mesh *mesh,
     }
     else { /* FROM_FACE/FROM_VOLUME */
            /* find a face on the derived mesh that uses this face */
-      MFace *mface;
-      OrigSpaceFace *osface;
-      int i;
-
-      i = index_dmcache;
+      int i = index_dmcache;
 
       if (i == DMCACHE_NOTFOUND || i >= mesh->totface) {
         return 0;
@@ -2062,8 +2059,8 @@ static int psys_map_index_on_dm(Mesh *mesh,
 
       /* modify the original weights to become
        * weights for the derived mesh face */
-      osface = CustomData_get_layer(&mesh->fdata, CD_ORIGSPACE);
-      mface = &mesh->mface[i];
+      OrigSpaceFace *osface = CustomData_get_layer(&mesh->fdata, CD_ORIGSPACE);
+      const MFace *mface = &mesh->mface[i];
 
       if (osface == NULL) {
         mapfw[0] = mapfw[1] = mapfw[2] = mapfw[3] = 0.0f;
@@ -2090,7 +2087,7 @@ void psys_particle_on_dm(Mesh *mesh_final,
                          float orco[3])
 {
   float tmpnor[3], mapfw[4];
-  float(*orcodata)[3];
+  const float(*orcodata)[3];
   int mapindex;
 
   if (!psys_map_index_on_dm(
@@ -3843,7 +3840,7 @@ static void psys_face_mat(Object *ob, Mesh *mesh, ParticleData *pa, float mat[4]
   float v[3][3];
   MFace *mface;
   OrigSpaceFace *osface;
-  float(*orcodata)[3];
+  const float(*orcodata)[3];
 
   int i = (ELEM(pa->num_dmcache, DMCACHE_ISCHILD, DMCACHE_NOTFOUND)) ? pa->num : pa->num_dmcache;
   if (i == -1 || i >= mesh->totface) {
@@ -4159,7 +4156,7 @@ static int get_particle_uv(Mesh *mesh,
                            bool from_vert)
 {
   MFace *mf;
-  MTFace *tf;
+  const MTFace *tf;
   int i;
 
   tf = CustomData_get_layer_named(&mesh->fdata, CD_MTFACE, name);
diff --git a/source/blender/blenkernel/intern/particle_distribute.c b/source/blender/blenkernel/intern/particle_distribute.c
index 244396af6e6..4be48efb2b5 100644
--- a/source/blender/blenkernel/intern/particle_distribute.c
+++ b/source/blender/blenkernel/intern/particle_distribute.c
@@ -808,7 +808,7 @@ static void exec_distribute_child(TaskPool *__restrict UNUSED(pool), void *taskd
 
 static int distribute_compare_orig_index(const void *p1, const void *p2, void *user_data)
 {
-  int *orig_index = (int *)user_data;
+  const int *orig_index = (const int *)user_data;
   int index1 = orig_index[*(const int *)p1];
   int index2 = orig_index[*(const int *)p2];
 
@@ -989,7 +989,7 @@ static int psys_thread_context_init_distribute(ParticleThreadContext *ctx,
 
     if (from == PART_FROM_VERT) {
       MVert *mv = mesh->mvert;
-      float(*orcodata)[3] = CustomData_get_layer(&mesh->vdata, CD_ORCO);
+      const float(*orcodata)[3] = CustomData_get_layer(&mesh->vdata, CD_ORCO);
       int totvert = mesh->totvert;
 
       tree = BLI_kdtree_3d_new(totvert);
@@ -1037,7 +1037,7 @@ static int psys_thread_context_init_distribute(ParticleThreadContext *ctx,
   if ((part->flag & PART_EDISTR || children) && from != PART_FROM_VERT) {
     MVert *v1, *v2, *v3, *v4;
     float totarea = 0.0f, co1[3], co2[3], co3[3], co4[3];
-    float(*orcodata)[3];
+    const float(*orcodata)[3];
 
     orcodata = CustomData_get_layer(&mesh->vdata, CD_ORCO);
 
@@ -1219,7 +1219,7 @@ static int psys_thread_context_init_distribute(ParticleThreadContext *ctx,
   /* For hair, sort by origindex (allows optimization's in rendering), */
   /* however with virtual parents the children need to be in random order. */
   if (part->type == PART_HAIR && !(part->childtype == PART_CHILD_FACES && part->parents != 0.0f)) {
-    int *orig_index = NULL;
+    const int *orig_index = NULL;
 
     if (from == PART_FROM_VERT) {
       if (mesh->totvert) {
@@ -1233,8 +1233,11 @@ static int psys_thread_context_init_distribute(ParticleThreadContext *ctx,
     }
 
     if (orig_index) {
-      BLI_qsort_r(
-          particle_element, totpart, sizeof(int), distribute_compare_orig_index, orig_index);
+      BLI_qsort_r(particle_element,
+                  totpart,
+                  sizeof(int),
+                  distribute_compare_orig_index,
+                  (void *)orig_index);
     }
   }
 
diff --git a/source/blender/blenkernel/intern/particle_system.c b/source/blender/blenkernel/intern/particle_system.c
index 7fdc60a265b..a7ab1536b1f 100644
--- a/source/blender/blenkernel/intern/particle_system.c
+++ b/source/blender/blenkernel/intern/particle_system.c
@@ -321,8 +321,9 @@ void psys_calc_dmcache(Object *ob, Mesh *mesh_final, Mesh *mesh_original, Partic
   if (!mesh_final->runtime.deformed_only) {
     /* Will use later to speed up subsurf/evaluated mesh. */
     LinkNode *node, *nodedmelem, **nodearray;
-    int totdmelem, totelem, i, *origindex, *origindex_poly = NULL;
-
+    int totdmelem, totelem, i;
+    const int *origindex;
+    const int *origindex_poly = NULL;
     if (psys->part->from == PART_FROM_VERT) {
       totdmelem = mesh_final->totvert;
 
diff --git a/source/blender/blenkernel/intern/pbvh_pixels.cc b/source/blender/blenkernel/intern/pbvh_pixels.cc
index 8b3fcffd9cd..40742ad36d5 100644
--- a/source/blender/blenkernel/intern/pbvh_pixels.cc
+++ b/source/blender/blenkernel/intern/pbvh_pixels.cc
@@ -108,7 +108,7 @@ struct EncodePixelsUserData {
   ImageUser *image_user;
   PBVH *pbvh;
   Vector<PBVHNode *> *nodes;
-  MLoopUV *ldata_uv;
+  const MLoopUV *ldata_uv;
 };
 
 static void do_encode_pixels(void *__restrict userdata,
@@ -283,7 +283,8 @@ static void update_pixels(PBVH *pbvh, Mesh *mesh, Image *image, ImageUser *image
     return;
   }
 
-  MLoopUV *ldata_uv = static_cast<MLoopUV *>(CustomData_get_layer(&mesh->ldata, CD_MLOOPUV));
+  const MLoopUV *ldata_uv = static_cast<const MLoopUV *>(
+      CustomData_get_layer(&mesh->ldata, CD_MLOOPUV));
   if (ldata_uv == nullptr) {
     return;
   }
diff --git a/source/blender/blenkernel/intern/subdiv_ccg_mask.c b/source/blender/blenkernel/intern/subdiv_ccg_mask.c
index 83f76f85a67..04a274d0215 100644
--- a/source/blender/blenkernel/intern/subdiv_ccg_mask.c
+++ b/source/blender/blenkernel/intern/subdiv_ccg_mask.c
@@ -155,8 +155,7 @@ static void mask_init_functions(SubdivCCGMaskEvaluator *mask_evaluator)
 bool BKE_subdiv_ccg_mask_init_from_paint(SubdivCCGMaskEvaluator *mask_evaluator,
                                          const struct Mesh *mesh)
 {
-  GridPaintMask *grid_paint_mask = CustomData_get_layer(&mesh->ldata, CD_GRID_PAINT_MASK);
-  if (grid_paint_mask == NULL) {
+  if (CustomData_get_layer(&mesh->ldata, CD_GRID_PAINT_MASK)) {
     return false;
   }
   /* Allocate all required memory. */
diff --git a/source/blender/blenkernel/intern/subsurf_ccg.c b/source/blender/blenkernel/intern/subsurf_ccg.c
index 5e7a0fc116b..04786f5dc5d 100644
--- a/source/blender/blenkernel/intern/subsurf_ccg.c
+++ b/source/blender/blenkernel/intern/subsurf_ccg.c
@@ -1670,7 +1670,6 @@ static void set_ccgdm_all_geometry(CCGDerivedMesh *ccgdm,
   int index;
   int i;
   int vertNum = 0, edgeNum = 0, faceNum = 0;
-  int *vertOrigIndex, *polyOrigIndex, *base_polyOrigIndex, *edgeOrigIndex;
   short *edgeFlags = ccgdm->edgeFlags;
   DMFlagMat *faceFlags = ccgdm->faceFlags;
   int *polyidx = NULL;
@@ -1687,7 +1686,6 @@ static void set_ccgdm_all_geometry(CCGDerivedMesh *ccgdm,
   int gridInternalEdges;
   WeightTable wtable = {NULL};
   MEdge *medge = NULL;
-  MPoly *mpoly = NULL;
   bool has_edge_cd;
 
   edgeSize = ccgSubSurf_getEdgeSize(ss);
@@ -1700,13 +1698,13 @@ static void set_ccgdm_all_geometry(CCGDerivedMesh *ccgdm,
 
   medge = dm->getEdgeArray(dm);
 
-  mpoly = CustomData_get_layer(&dm->polyData, CD_MPOLY);
-  base_polyOrigIndex = CustomData_get_layer(&dm->polyData, CD_ORIGINDEX);
+  const MPoly *mpoly = CustomData_get_layer(&dm->polyData, CD_MPOLY);
+  const int *base_polyOrigIndex = CustomData_get_layer(&dm->polyData, CD_ORIGINDEX);
 
-  vertOrigIndex = DM_get_vert_data_layer(&ccgdm->dm, CD_ORIGINDEX);
-  edgeOrigIndex = DM_get_edge_data_layer(&ccgdm->dm, CD_ORIGINDEX);
+  int *vertOrigIndex = DM_get_vert_data_layer(&ccgdm->dm, CD_ORIGINDEX);
+  int *edgeOrigIndex = DM_get_edge_data_layer(&ccgdm->dm, CD_ORIGINDEX);
 
-  polyOrigIndex = DM_get_poly_data_layer(&ccgdm->dm, CD_ORIGINDEX);
+  int *polyOrigIndex = DM_get_poly_data_layer(&ccgdm->dm, CD_ORIGINDEX);
 
   has_edge_cd = ((ccgdm->dm.edgeData.totlayer - (edgeOrigIndex ? 1 : 0)) != 0);
 
diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
index d992d426b9a..eeec55a7b06 100644
--- a/source/blender/blenloader/intern/versioning_280.c
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -4892,7 +4892,7 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
     /* Default Face Set Color. */
     for (Mesh *me = bmain->meshes.first; me != NULL; me = me->id.next) {
       if (me->totpoly > 0) {
-        int *face_sets = CustomData_get_layer(&me->pdata, CD_SCULPT_FACE_SETS);
+        const int *face_sets = CustomData_get_layer(&me->pdata, CD_SCULPT_FACE_SETS);
         if (face_sets) {
           me->face_sets_color_default = abs(face_sets[0]);
         }
diff --git a/source/blender/draw/intern/draw_cache_impl_subdivision.cc b/source/blender/draw/intern/draw_cache_impl_subdivision.cc
index 8eb0509d615..cfdf059ca37 100644
--- a/source/blender/draw/intern/draw_cache_impl_subdivision.cc
+++ b/source/blender/draw/intern/draw_cache_impl_subdivision.cc
@@ -745,8 +745,8 @@ struct DRWCacheBuildingContext {
   /* Origindex layers from the mesh to directly look up during traversal the origindex from the
    * base mesh for edit data so that we do not have to handle yet another GPU buffer and do this in
    * the shaders. */
-  int *v_origindex;
-  int *e_origindex;
+  const int *v_origindex;
+  const int *e_origindex;
 };
 
 static bool draw_subdiv_topology_info_cb(const SubdivForeachContext *foreach_context,
diff --git a/source/blender/draw/intern/mesh_extractors/extract_mesh.h b/source/blender/draw/intern/mesh_extractors/extract_mesh.h
index d55386dfd7d..b88cd9e77d2 100644
--- a/source/blender/draw/intern/mesh_extractors/extract_mesh.h
+++ b/source/blender/draw/intern/mesh_extractors/extract_mesh.h
@@ -67,7 +67,7 @@ typedef struct MeshRenderData {
   const float (*bm_poly_normals)[3];
   const float (*bm_poly_centers)[3];
 
-  int *v_origindex, *e_origindex, *p_origindex;
+  const int *v_origindex, *e_origindex, *p_origindex;
   int edge_crease_ofs;
   int vert_crease_ofs;
   int bweight_ofs;
diff --git a/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_edituv_stretch_angle.cc b/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_edituv_stretch_angle.cc
index 4ced14ab11a..14f61dcd739 100644
--- a/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_edituv_stretch_angle.cc
+++ b/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_edituv_stretch_angle.cc
@@ -26,7 +26,7 @@ struct UVStretchAngle {
 
 struct MeshExtract_StretchAngle_Data {
   UVStretchAngle *vbo_data;
-  MLoopUV *luv;
+  const MLoopUV *luv;
   float auv[2][2], last_auv[2];
   float av[2][3], last_av[3];
   int cd_ofs;
@@ -98,7 +98,7 @@ static void extract_edituv_stretch_angle_init(const MeshRenderData *mr,
   }
   else {
     BLI_assert(ELEM(mr->extract_type, MR_EXTRACT_MAPPED, MR_EXTRACT_MESH));
-    data->luv = (MLoopUV *)CustomData_get_layer(&mr->me->ldata, CD_MLOOPUV);
+    data->luv = (const MLoopUV *)CustomData_get_layer(&mr->me->ldata, CD_MLOOPUV);
   }
 }
 
diff --git a/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_fdots_uv.cc b/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_fdots_uv.cc
index 26f0b07f676..e7a3cb03903 100644
--- a/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_fdots_uv.cc
+++ b/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_fdots_uv.cc
@@ -17,7 +17,7 @@ namespace blender::draw {
 
 struct MeshExtract_FdotUV_Data {
   float (*vbo_data)[2];
-  MLoopUV *uv_data;
+  const MLoopUV *uv_data;
   int cd_ofs;
 };
 
@@ -49,7 +49,7 @@ static void extract_fdots_uv_init(const MeshRenderData *mr,
     data->cd_ofs = CustomData_get_offset(&mr->bm->ldata, CD_MLOOPUV);
   }
   else {
-    data->uv_data = (MLoopUV *)CustomData_get_layer(&mr->me->ldata, CD_MLOOPUV);
+    data->uv_data = (const MLoopUV *)CustomData_get_layer(&mr->me->ldata, CD_MLOOPUV);
   }
 }
 
diff --git a/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_orco.cc b/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_orco.cc
index ed1a0ccd178..b45a73a27c0 100644
--- a/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_orco.cc
+++ b/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_orco.cc
@@ -17,7 +17,7 @@ namespace blender::draw {
 
 struct MeshExtract_Orco_Data {
   float (*vbo_data)[4];
-  float (*orco)[3];
+  const float (*orco)[3];
 };
 
 static void extract_orco_init(const MeshRenderData *mr,
@@ -42,7 +42,7 @@ static void extract_orco_init(const MeshRenderData *mr,
 
   MeshExtract_Orco_Data *data = static_cast<MeshExtract_Orco_Data *>(tls_data);
   data->vbo_data = (float(*)[4])GPU_vertbuf_get_data(vbo);
-  data->orco = static_cast<float(*)[3]>(CustomData_get_layer(cd_vdata, CD_ORCO));
+  data->orco = static_cast<const float(*)[3]>(CustomData_get_layer(cd_vdata, CD_ORCO));
   /* Make sure `orco` layer was requested only if needed! */
   BLI_assert(data->orco);
 }
@@ -105,7 +105,7 @@ static void extract_orco_init_subdiv(const DRWSubdivCache *subdiv_cache,
   float(*coarse_vbo_data)[4] = static_cast<float(*)[4]>(GPU_vertbuf_get_data(coarse_vbo));
 
   CustomData *cd_vdata = &mr->me->vdata;
-  float(*orco)[3] = static_cast<float(*)[3]>(CustomData_get_layer(cd_vdata, CD_ORCO));
+  const float(*orco)[3] = static_cast<const float(*)[3]>(CustomData_get_layer(cd_vdata, CD_ORCO));
 
   if (mr->extract_type == MR_EXTRACT_MESH) {
     const MLoop *mloop = mr->mloop;
diff --git a/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_pos_nor.cc b/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_pos_nor.cc
index ea46d9c4caa..c8c91d45542 100644
--- a/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_pos_nor.cc
+++ b/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_pos_nor.cc
@@ -220,7 +220,7 @@ static void extract_pos_nor_init_subdiv(const DRWSubdivCache *subdiv_cache,
 
   if (subdiv_cache->use_custom_loop_normals) {
     Mesh *coarse_mesh = subdiv_cache->mesh;
-    float(*lnors)[3] = static_cast<float(*)[3]>(
+    const float(*lnors)[3] = static_cast<float(*)[3]>(
         CustomData_get_layer(&coarse_mesh->ldata, CD_NORMAL));
     BLI_assert(lnors != nullptr);
 
diff --git a/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_sculpt_data.cc b/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_sculpt_data.cc
index 96595df9276..5658ed85c8b 100644
--- a/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_sculpt_data.cc
+++ b/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_sculpt_data.cc
@@ -42,8 +42,8 @@ static void extract_sculpt_data_init(const MeshRenderData *mr,
   CustomData *cd_vdata = (mr->extract_type == MR_EXTRACT_BMESH) ? &mr->bm->vdata : &mr->me->vdata;
   CustomData *cd_pdata = (mr->extract_type == MR_EXTRACT_BMESH) ? &mr->bm->pdata : &mr->me->pdata;
 
-  float *cd_mask = (float *)CustomData_get_layer(cd_vdata, CD_PAINT_MASK);
-  int *cd_face_set = (int *)CustomData_get_layer(cd_pdata, CD_SCULPT_FACE_SETS);
+  const float *cd_mask = (const float *)CustomData_get_layer(cd_vdata, CD_PAINT_MASK);
+  const int *cd_face_set = (const int *)CustomData_get_layer(cd_pdata, CD_SCULPT_FACE_SETS);
 
   GPU_vertbuf_init_with_format(vbo, format);
   GPU_vertbuf_data_alloc(vbo, mr->loop_len);
@@ -54,7 +54,7 @@ static void extract_sculpt_data_init(const MeshRenderData *mr,
   };
 
   gpuSculptData *vbo_data = (gpuSculptData *)GPU_vertbuf_get_data(vbo);
-  MLoop *loops = (MLoop *)CustomData_get_layer(cd_ldata, CD_MLOOP);
+  const MLoop *loops = (const MLoop *)CustomData_get_layer(cd_ldata, CD_MLOOP);
 
   if (mr->extract_type == MR_EXTRACT_BMESH) {
     int cd_mask_ofs = CustomData_get_offset(cd_vdata, CD_PAINT_MASK);
@@ -126,7 +126,7 @@ static void extract_sculpt_data_init_subdiv(const DRWSubdivCache *subdiv_cache,
   /* First, interpolate mask if available. */
   GPUVertBuf *mask_vbo = nullptr;
   GPUVertBuf *subdiv_mask_vbo = nullptr;
-  float *cd_mask = (float *)CustomData_get_layer(cd_vdata, CD_PAINT_MASK);
+  const float *cd_mask = (const float *)CustomData_get_layer(cd_vdata, CD_PAINT_MASK);
 
   if (cd_mask) {
     GPUVertFormat mask_format = {0};
@@ -167,7 +167,7 @@ static void extract_sculpt_data_init_subdiv(const DRWSubdivCache *subdiv_cache,
   };
 
   gpuFaceSet *face_sets = (gpuFaceSet *)GPU_vertbuf_get_data(face_set_vbo);
-  int *cd_face_set = (int *)CustomData_get_layer(cd_pdata, CD_SCULPT_FACE_SETS);
+  const int *cd_face_set = (const int *)CustomData_get_layer(cd_pdata, CD_SCULPT_FACE_SETS);
 
   GPUVertFormat *format = get_sculpt_data_format();
   GPU_vertbuf_init_build_on_device(vbo, format, subdiv_cache->num_subdiv_loops);
diff --git a/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_tan.cc b/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_tan.cc
index 25f78d68914..91cd675d32f 100644
--- a/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_tan.cc
+++ b/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_tan.cc
@@ -291,7 +291,8 @@ static void extract_tan_init_subdiv(const DRWSubdivCache *subdiv_cache,
   for (int i = 0; i < tan_len; i++) {
     float(*tan_data)[4] = (float(*)[4])GPU_vertbuf_get_data(coarse_vbo);
     const char *name = tangent_names[i];
-    float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_named(&loop_data, CD_TANGENT, name);
+    const float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_named(
+        &loop_data, CD_TANGENT, name);
     for (int ml_index = 0; ml_index < mr->loop_len; ml_index++) {
       copy_v3_v3(*tan_data, layer_data[ml_index]);
       (*tan_data)[3] = (layer_data[ml_index][3] > 0.0f) ? 1.0f : -1.0f;
@@ -306,7 +307,7 @@ static void extract_tan_init_subdiv(const DRWSubdivCache *subdiv_cache,
   }
   if (use_orco_tan) {
     float(*tan_data)[4] = (float(*)[4])GPU_vertbuf_get_data(coarse_vbo);
-    float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_n(&loop_data, CD_TANGENT, 0);
+    const float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_n(&loop_data, CD_TANGENT, 0);
     for (int ml_index = 0; ml_index < mr->loop_len; ml_index++) {
       copy_v3_v3(*tan_data, layer_data[ml_index]);
       (*tan_data)[3] = (layer_data[ml_index][3] > 0.0f) ? 1.0f : -1.0f;
diff --git a/source/blender/editors/curves/intern/curves_ops.cc b/source/blender/editors/curves/intern/curves_ops.cc
index a2945e8b7e6..5588f7440a8 100644
--- a/source/blender/editors/curves/intern/curves_ops.cc
+++ b/source/blender/editors/curves/intern/curves_ops.cc
@@ -195,7 +195,7 @@ static void try_convert_single_object(Object &curves_ob,
 
   /* Prepare utility data structure to map hair roots to mfaces. */
   const Span<int> mface_to_poly_map{
-      static_cast<int *>(CustomData_get_layer(&surface_me.fdata, CD_ORIGINDEX)),
+      static_cast<const int *>(CustomData_get_layer(&surface_me.fdata, CD_ORIGINDEX)),
       surface_me.totface};
   Array<Vector<int>> poly_to_mface_map(surface_me.totpoly);
   for (const int mface_i : mface_to_poly_map.index_range()) {
diff --git a/source/blender/editors/mesh/mesh_data.c b/source/blender/editors/mesh/mesh_data.c
index d11f0b490c1..6b857fccec7 100644
--- a/source/blender/editors/mesh/mesh_data.c
+++ b/source/blender/editors/mesh/mesh_data.c
@@ -549,9 +549,9 @@ int ED_mesh_sculpt_color_add(
     }
 
     if (CustomData_has_layer(&me->vdata, CD_PROP_COLOR) && do_init) {
-      MPropCol *color_data = CustomData_get_layer(&me->vdata, CD_PROP_COLOR);
+      const MPropCol *color_data = CustomData_get_layer(&me->vdata, CD_PROP_COLOR);
       CustomData_add_layer_named(
-          &me->vdata, CD_PROP_COLOR, CD_DUPLICATE, color_data, me->totvert, name);
+          &me->vdata, CD_PROP_COLOR, CD_DUPLICATE, (MPropCol *)color_data, me->totvert, name);
     }
     else {
       CustomData_add_layer_named(&me->vdata, CD_PROP_COLOR, CD_DEFAULT, NULL, me->totvert, name);
diff --git a/source/blender/editors/mesh/meshtools.c b/source/blender/editors/mesh/meshtools.c
index 9575fde68f0..d4ed49de34a 100644
--- a/source/blender/editors/mesh/meshtools.c
+++ b/source/blender/editors/mesh/meshtools.c
@@ -1273,7 +1273,6 @@ bool ED_mesh_pick_face_vert(
     MLoop *me_eval_mloop;
     MVert *me_eval_mvert;
     uint me_eval_mpoly_len;
-    const int *index_mp_to_orig;
 
     me_eval_mpoly = me_eval->mpoly;
     me_eval_mloop = me_eval->mloop;
@@ -1281,7 +1280,7 @@ bool ED_mesh_pick_face_vert(
 
     me_eval_mpoly_len = me_eval->totpoly;
 
-    index_mp_to_orig = CustomData_get_layer(&me_eval->pdata, CD_ORIGINDEX);
+    const int *index_mp_to_orig = CustomData_get_layer(&me_eval->pdata, CD_ORIGINDEX);
 
     /* tag all verts using this face */
     if (index_mp_to_orig) {
@@ -1313,8 +1312,7 @@ bool ED_mesh_pick_face_vert(
 
     /* map 'dm -> me' r_index if possible */
     if (v_idx_best != ORIGINDEX_NONE) {
-      const int *index_mv_to_orig;
-      index_mv_to_orig = CustomData_get_layer(&me_eval->vdata, CD_ORIGINDEX);
+      const int *index_mv_to_orig = CustomData_get_layer(&me_eval->vdata, CD_ORIGINDEX);
       if (index_mv_to_orig) {
         v_idx_best = index_mv_to_orig[v_idx_best];
       }
diff --git a/source/blender/editors/object/object_bake_api.c b/source/blender/editors/object/object_bake_api.c
index a7379d7e492..114b2ce8102 100644
--- a/source/blender/editors/object/object_bake_api.c
+++ b/source/blender/editors/object/object_bake_api.c
@@ -446,9 +446,9 @@ static bool bake_object_check(ViewLayer *view_layer,
   }
 
   if (target == R_BAKE_TARGET_VERTEX_COLORS) {
-    MPropCol *mcol = CustomData_get_layer(&me->vdata, CD_PROP_COLOR);
+    const MPropCol *mcol = CustomData_get_layer(&me->vdata, CD_PROP_COLOR);
     const bool mcol_valid = (mcol != NULL);
-    MLoopCol *mloopcol = CustomData_get_layer(&me->ldata, CD_PROP_BYTE_COLOR);
+    const MLoopCol *mloopcol = CustomData_get_layer(&me->ldata, CD_PROP_BYTE_COLOR);
     if (mloopcol == NULL && !mcol_valid) {
       BKE_reportf(reports,
                   RPT_ERROR,
@@ -943,9 +943,9 @@ static bool bake_targets_init_vertex_colors(BakeTargets *targets, Object *ob, Re
   }
 
   Mesh *me = ob->data;
-  MPropCol *mcol = CustomData_get_layer(&me->vdata, CD_PROP_COLOR);
+  const MPropCol *mcol = CustomData_get_layer(&me->vdata, CD_PROP_COLOR);
   const bool mcol_valid = (mcol != NULL);
-  MLoopCol *mloopcol = CustomData_get_layer(&me->ldata, CD_PROP_BYTE_COLOR);
+  const MLoopCol *mloopcol = CustomData_get_layer(&me->ldata, CD_PROP_BYTE_COLOR);
   if (mloopcol == NULL && !mcol_valid) {
     BKE_report(reports, RPT_ERROR, "No vertex colors layer found to bake to");
     return false;
diff --git a/source/blender/editors/sculpt_paint/sculpt_face_set.c b/source/blender/editors/sculpt_paint/sculpt_face_set.c
index 7171c241534..67bf7b3286c 100644
--- a/source/blender/editors/sculpt_paint/sculpt_face_set.c
+++ b/source/blender/editors/sculpt_paint/sculpt_face_set.c
@@ -60,7 +60,7 @@
 
 int ED_sculpt_face_sets_find_next_available_id(struct Mesh *mesh)
 {
-  int *face_sets = CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS);
+  const int *face_sets = CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS);
   if (!face_sets) {
     return SCULPT_FACE_SET_NONE;
   }
diff --git a/source/blender/editors/sculpt_paint/sculpt_ops.c b/source/blender/editors/sculpt_paint/sculpt_ops.c
index 5aa1dbef74c..9c4ae446125 100644
--- a/source/blender/editors/sculpt_paint/sculpt_ops.c
+++ b/source/blender/editors/sculpt_paint/sculpt_ops.c
@@ -639,14 +639,14 @@ static int vertex_to_loop_colors_exec(bContext *C, wmOperator *UNUSED(op))
   }
   MPropCol *vertcols = CustomData_get_layer_n(&mesh->vdata, CD_PROP_COLOR, MPropCol_layer_n);
 
-  MLoop *loops = CustomData_get_layer(&mesh->ldata, CD_MLOOP);
-  MPoly *polys = CustomData_get_layer(&mesh->pdata, CD_MPOLY);
+  const MLoop *loops = CustomData_get_layer(&mesh->ldata, CD_MLOOP);
+  const MPoly *polys = CustomData_get_layer(&mesh->pdata, CD_MPOLY);
 
   for (int i = 0; i < mesh->totpoly; i++) {
-    MPoly *c_poly = &polys[i];
+    const MPoly *c_poly = &polys[i];
     for (int j = 0; j < c_poly->totloop; j++) {
       int loop_index = c_poly->loopstart + j;
-      MLoop *c_loop = &loops[c_poly->loopstart + j];
+      const MLoop *c_loop = &loops[c_poly->loopstart + j];
       float srgb_color[4];
       linearrgb_to_srgb_v4(srgb_color, vertcols[c_loop->v].color);
       loopcols[loop_index].r = (char)(srgb_color[0] * 255);
@@ -719,14 +719,14 @@ static int loop_to_vertex_colors_exec(bContext *C, wmOperator *UNUSED(op))
   }
   MPropCol *vertcols = CustomData_get_layer_n(&mesh->vdata, CD_PROP_COLOR, MPropCol_layer_n);
 
-  MLoop *loops = CustomData_get_layer(&mesh->ldata, CD_MLOOP);
-  MPoly *polys = CustomData_get_layer(&mesh->pdata, CD_MPOLY);
+  const MLoop *loops = CustomData_get_layer(&mesh->ldata, CD_MLOOP);
+  const MPoly *polys = CustomData_get_layer(&mesh->pdata, CD_MPOLY);
 
   for (int i = 0; i < mesh->totpoly; i++) {
-    MPoly *c_poly = &polys[i];
+    const MPoly *c_poly = &polys[i];
     for (int j = 0; j < c_poly->totloop; j++) {
       int loop_index = c_poly->loopstart + j;
-      MLoop *c_loop = &loops[c_poly->loopstart + j];
+      const MLoop *c_loop = &loops[c_poly->loopstart + j];
       vertcols[c_loop->v].color[0] = (loopcols[loop_index].r / 255.0f);
       vertcols[c_loop->v].color[1] = (loopcols[loop_index].g / 255.0f);
       vertcols[c_loop->v].color[2] = (loopcols[loop_index].b / 255.0f);
diff --git a/source/blender/editors/sculpt_paint/sculpt_undo.c b/source/blender/editors/sculpt_paint/sculpt_undo.c
index 5867dc558de..1fee20444e7 100644
--- a/source/blender/editors/sculpt_paint/sculpt_undo.c
+++ b/source/blender/editors/sculpt_paint/sculpt_undo.c
@@ -1265,7 +1265,7 @@ static SculptUndoNode *sculpt_undo_face_sets_push(Object *ob, SculptUndoType typ
 
   unode->face_sets = MEM_callocN(me->totpoly * sizeof(int), "sculpt face sets");
 
-  int *face_sets = CustomData_get_layer(&me->pdata, CD_SCULPT_FACE_SETS);
+  const int *face_sets = CustomData_get_layer(&me->pdata, CD_SCULPT_FACE_SETS);
   for (int i = 0; i < me->totpoly; i++) {
     unode->face_sets[i] = face_sets[i];
   }
diff --git a/source/blender/editors/space_spreadsheet/spreadsheet_data_source_geometry.cc b/source/blender/editors/space_spreadsheet/spreadsheet_data_source_geometry.cc
index 66eced27b32..7f696efabf7 100644
--- a/source/blender/editors/space_spreadsheet/spreadsheet_data_source_geometry.cc
+++ b/source/blender/editors/space_spreadsheet/spreadsheet_data_source_geometry.cc
@@ -256,7 +256,7 @@ IndexMask GeometryDataSource::apply_selection_filter(Vector<int64_t> &indices) c
   BMesh *bm = mesh_orig->edit_mesh->bm;
   BM_mesh_elem_table_ensure(bm, BM_VERT);
 
-  int *orig_indices = (int *)CustomData_get_layer(&mesh_eval->vdata, CD_ORIGINDEX);
+  const int *orig_indices = (int *)CustomData_get_layer(&mesh_eval->vdata, CD_ORIGINDEX);
   if (orig_indices != nullptr) {
     /* Use CD_ORIGINDEX layer if it exists. */
     VArray<bool> selection = mesh_component->attribute_try_adapt_domain<bool>(
diff --git a/source/blender/freestyle/intern/blender_interface/BlenderFileLoader.cpp b/source/blender/freestyle/intern/blender_interface/BlenderFileLoader.cpp
index 9304e6aa3fb..e76e74b89e4 100644
--- a/source/blender/freestyle/intern/blender_interface/BlenderFileLoader.cpp
+++ b/source/blender/freestyle/intern/blender_interface/BlenderFileLoader.cpp
@@ -370,7 +370,7 @@ int BlenderFileLoader::testDegenerateTriangle(float v1[3], float v2[3], float v3
   return 0;
 }
 
-static bool testEdgeMark(Mesh *me, FreestyleEdge *fed, const MLoopTri *lt, int i)
+static bool testEdgeMark(Mesh *me, const FreestyleEdge *fed, const MLoopTri *lt, int i)
 {
   MLoop *mloop = &me->mloop[lt->tri[i]];
   MLoop *mloop_next = &me->mloop[lt->tri[(i + 1) % 3]];
@@ -395,7 +395,7 @@ void BlenderFileLoader::insertShapeNode(Object *ob, Mesh *me, int id)
 
   // Compute loop normals
   BKE_mesh_calc_normals_split(me);
-  float(*lnors)[3] = nullptr;
+  const float(*lnors)[3] = nullptr;
 
   if (CustomData_has_layer(&me->ldata, CD_NORMAL)) {
     lnors = (float(*)[3])CustomData_get_layer(&me->ldata, CD_NORMAL);
@@ -405,8 +405,8 @@ void BlenderFileLoader::insertShapeNode(Object *ob, Mesh *me, int id)
   MVert *mvert = me->mvert;
   MLoop *mloop = me->mloop;
   MPoly *mpoly = me->mpoly;
-  FreestyleEdge *fed = (FreestyleEdge *)CustomData_get_layer(&me->edata, CD_FREESTYLE_EDGE);
-  FreestyleFace *ffa = (FreestyleFace *)CustomData_get_layer(&me->pdata, CD_FREESTYLE_FACE);
+  const FreestyleEdge *fed = (FreestyleEdge *)CustomData_get_layer(&me->edata, CD_FREESTYLE_EDGE);
+  const FreestyleFace *ffa = (FreestyleFace *)CustomData_get_layer(&me->pdata, CD_FREESTYLE_FACE);
 
   // Compute view matrix
   Object *ob_camera_eval = DEG_get_evaluated_object(_depsgraph, RE_GetCamera(_re));
diff --git a/source/blender/io/collada/GeometryExporter.cpp b/source/blender/io/collada/GeometryExporter.cpp
index 3952a4ae334..9886b4de6e0 100644
--- a/source/blender/io/collada/GeometryExporter.cpp
+++ b/source/blender/io/collada/GeometryExporter.cpp
@@ -619,7 +619,7 @@ void GeometryExporter::create_normals(std::vector<Normal> &normals,
   MVert *verts = me->mvert;
   const float(*vert_normals)[3] = BKE_mesh_vertex_normals_ensure(me);
   MLoop *mloops = me->mloop;
-  float(*lnors)[3] = nullptr;
+  const float(*lnors)[3] = nullptr;
   bool use_custom_normals = false;
 
   BKE_mesh_calc_normals_split(me);
diff --git a/source/blender/makesrna/intern/rna_mesh.c b/source/blender/makesrna/intern/rna_mesh.c
index 38d473f04dd..7a6f78d0300 100644
--- a/source/blender/makesrna/intern/rna_mesh.c
+++ b/source/blender/makesrna/intern/rna_mesh.c
@@ -560,7 +560,7 @@ static void rna_MeshVertex_undeformed_co_get(PointerRNA *ptr, float values[3])
 {
   Mesh *me = rna_mesh(ptr);
   MVert *mvert = (MVert *)ptr->data;
-  float(*orco)[3] = CustomData_get_layer(&me->vdata, CD_ORCO);
+  const float(*orco)[3] = CustomData_get_layer(&me->vdata, CD_ORCO);
 
   if (orco) {
     /* orco is normalized to 0..1, we do inverse to match mvert->co */
diff --git a/source/blender/modifiers/intern/MOD_displace.c b/source/blender/modifiers/intern/MOD_displace.c
index 7ad7d6eef3d..149cf0c0cbb 100644
--- a/source/blender/modifiers/intern/MOD_displace.c
+++ b/source/blender/modifiers/intern/MOD_displace.c
@@ -310,13 +310,11 @@ static void displaceModifier_do(DisplaceModifierData *dmd,
     CustomData *ldata = &mesh->ldata;
 
     if (CustomData_has_layer(ldata, CD_CUSTOMLOOPNORMAL)) {
-      float(*clnors)[3] = NULL;
-
       if (!CustomData_has_layer(ldata, CD_NORMAL)) {
         BKE_mesh_calc_normals_split(mesh);
       }
 
-      clnors = CustomData_get_layer(ldata, CD_NORMAL);
+      float(*clnors)[3] = CustomData_get_layer(ldata, CD_NORMAL);
       vert_clnors = MEM_malloc_arrayN(verts_num, sizeof(*vert_clnors), __func__);
       BKE_mesh_normals_loop_to_vertex(
           verts_num, mesh->mloop, mesh->totloop, (const float(*)[3])clnors, vert_clnors);
diff --git a/source/blender/modifiers/intern/MOD_explode.c b/source/blender/modifiers/intern/MOD_explode.c
index 9e2bb79138e..a1fcc77511d 100644
--- a/source/blender/modifiers/intern/MOD_explode.c
+++ b/source/blender/modifiers/intern/MOD_explode.c
@@ -124,7 +124,7 @@ static void createFacepa(ExplodeModifierData *emd, ParticleSystemModifierData *p
 
   /* set protected verts */
   if (emd->vgroup) {
-    MDeformVert *dvert = CustomData_get_layer(&mesh->vdata, CD_MDEFORMVERT);
+    const MDeformVert *dvert = CustomData_get_layer(&mesh->vdata, CD_MDEFORMVERT);
     if (dvert) {
       const int defgrp_index = emd->vgroup - 1;
       for (i = 0; i < totvert; i++, dvert++) {
diff --git a/source/blender/modifiers/intern/MOD_mask.cc b/source/blender/modifiers/intern/MOD_mask.cc
index 900dee98268..0813901fc49 100644
--- a/source/blender/modifiers/intern/MOD_mask.cc
+++ b/source/blender/modifiers/intern/MOD_mask.cc
@@ -91,7 +91,7 @@ static void updateDepsgraph(ModifierData *md, const ModifierUpdateDepsgraphConte
 }
 
 /* A vertex will be in the mask if a selected bone influences it more than a certain threshold. */
-static void compute_vertex_mask__armature_mode(MDeformVert *dvert,
+static void compute_vertex_mask__armature_mode(const MDeformVert *dvert,
                                                Mesh *mesh,
                                                Object *armature_ob,
                                                float threshold,
@@ -125,7 +125,7 @@ static void compute_vertex_mask__armature_mode(MDeformVert *dvert,
 }
 
 /* A vertex will be in the mask if the vertex group influences it more than a certain threshold. */
-static void compute_vertex_mask__vertex_group_mode(MDeformVert *dvert,
+static void compute_vertex_mask__vertex_group_mode(const MDeformVert *dvert,
                                                    int defgrp_index,
                                                    float threshold,
                                                    MutableSpan<bool> r_vertex_mask)
@@ -347,7 +347,7 @@ static void copy_masked_vertices_to_new_mesh(const Mesh &src_mesh,
 }
 
 static float get_interp_factor_from_vgroup(
-    MDeformVert *dvert, int defgrp_index, float threshold, uint v1, uint v2)
+    const MDeformVert *dvert, int defgrp_index, float threshold, uint v1, uint v2)
 {
   /* NOTE: this calculation is done twice for every vertex,
    * instead of storing it the first time and then reusing it. */
@@ -360,7 +360,7 @@ static void add_interp_verts_copy_edges_to_new_mesh(const Mesh &src_mesh,
                                                     Mesh &dst_mesh,
                                                     Span<bool> vertex_mask,
                                                     Span<int> vertex_map,
-                                                    MDeformVert *dvert,
+                                                    const MDeformVert *dvert,
                                                     int defgrp_index,
                                                     float threshold,
                                                     uint edges_masked_num,
@@ -478,7 +478,7 @@ static void add_interpolated_polys_to_new_mesh(const Mesh &src_mesh,
                                                Span<bool> vertex_mask,
                                                Span<int> vertex_map,
                                                Span<int> edge_map,
-                                               MDeformVert *dvert,
+                                               const MDeformVert *dvert,
                                                int defgrp_index,
                                                float threshold,
                                                Span<int> masked_poly_indices,
@@ -619,7 +619,8 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *UNUSED(ctx)
                                  (mmd->flag & MOD_MASK_SMOOTH);
 
   /* Return empty or input mesh when there are no vertex groups. */
-  MDeformVert *dvert = (MDeformVert *)CustomData_get_layer(&mesh->vdata, CD_MDEFORMVERT);
+  const MDeformVert *dvert = (const MDeformVert *)CustomData_get_layer(&mesh->vdata,
+                                                                       CD_MDEFORMVERT);
   if (dvert == nullptr) {
     return invert_mask ? mesh : BKE_mesh_new_nomain_from_template(mesh, 0, 0, 0, 0, 0);
   }
diff --git a/source/blender/modifiers/intern/MOD_normal_edit.c b/source/blender/modifiers/intern/MOD_normal_edit.c
index fe05f48a868..c215ac601a1 100644
--- a/source/blender/modifiers/intern/MOD_normal_edit.c
+++ b/source/blender/modifiers/intern/MOD_normal_edit.c
@@ -136,7 +136,7 @@ static void mix_normals(const float mix_factor,
   if (dvert) {
     facs = MEM_malloc_arrayN((size_t)loops_num, sizeof(*facs), __func__);
     BKE_defvert_extract_vgroup_to_loopweights(
-        dvert, defgrp_index, verts_num, mloop, loops_num, facs, use_invert_vgroup);
+        dvert, defgrp_index, verts_num, mloop, loops_num, use_invert_vgroup, facs);
   }
 
   for (i = loops_num, no_new = nos_new, no_old = nos_old, wfac = facs; i--;
@@ -532,14 +532,13 @@ static Mesh *normalEditModifier_do(NormalEditModifierData *enmd,
   MDeformVert *dvert;
 
   float(*loopnors)[3] = NULL;
-  short(*clnors)[2] = NULL;
 
   CustomData *ldata = &result->ldata;
 
   const float(*vert_normals)[3] = BKE_mesh_vertex_normals_ensure(result);
   const float(*poly_normals)[3] = BKE_mesh_poly_normals_ensure(result);
 
-  clnors = CustomData_get_layer(ldata, CD_CUSTOMLOOPNORMAL);
+  short(*clnors)[2] = CustomData_get_layer(ldata, CD_CUSTOMLOOPNORMAL);
   if (use_current_clnors) {
     clnors = CustomData_duplicate_referenced_layer(ldata, CD_CUSTOMLOOPNORMAL, loops_num);
     loopnors = MEM_malloc_arrayN((size_t)loops_num, sizeof(*loopnors), __func__);
diff --git a/source/blender/modifiers/intern/MOD_screw.c b/source/blender/modifiers/intern/MOD_screw.c
index 55fca7e8ecb..4157acf8bac 100644
--- a/source/blender/modifiers/intern/MOD_screw.c
+++ b/source/blender/modifiers/intern/MOD_screw.c
@@ -182,7 +182,6 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
   ScrewModifierData *ltmd = (ScrewModifierData *)md;
   const bool use_render_params = (ctx->flag & MOD_APPLY_RENDER) != 0;
 
-  int *origindex;
   int mpoly_index = 0;
   uint step;
   uint i, j;
@@ -397,7 +396,7 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
     CustomData_add_layer(&result->pdata, CD_ORIGINDEX, CD_CALLOC, NULL, (int)maxPolys);
   }
 
-  origindex = CustomData_get_layer(&result->pdata, CD_ORIGINDEX);
+  int *origindex = CustomData_get_layer(&result->pdata, CD_ORIGINDEX);
 
   CustomData_copy_data(&mesh->vdata, &result->vdata, 0, 0, (int)totvert);
 
diff --git a/source/blender/modifiers/intern/MOD_skin.c b/source/blender/modifiers/intern/MOD_skin.c
index 7f96dcb82fb..5f238209015 100644
--- a/source/blender/modifiers/intern/MOD_skin.c
+++ b/source/blender/modifiers/intern/MOD_skin.c
@@ -881,34 +881,29 @@ static int calc_edge_subdivisions(const MVert *mvert,
 
 /* Take a Mesh and subdivide its edges to keep skin nodes
  * reasonably close. */
-static Mesh *subdivide_base(Mesh *orig)
+static Mesh *subdivide_base(const Mesh *orig)
 {
-  Mesh *result;
-  MVertSkin *orignode, *outnode;
-  MVert *origvert, *outvert;
-  MEdge *origedge, *outedge, *e;
-  MDeformVert *origdvert, *outdvert;
-  int orig_vert_num, orig_edge_num;
-  int subd_num, *degree, *edge_subd;
+  const MEdge *e;
+  int subd_num;
   int i, j, k, u, v;
   float radrat;
 
-  orignode = CustomData_get_layer(&orig->vdata, CD_MVERT_SKIN);
-  origvert = orig->mvert;
-  origedge = orig->medge;
-  origdvert = orig->dvert;
-  orig_vert_num = orig->totvert;
-  orig_edge_num = orig->totedge;
+  const MVertSkin *orignode = CustomData_get_layer(&orig->vdata, CD_MVERT_SKIN);
+  const MVert *origvert = orig->mvert;
+  const MEdge *origedge = orig->medge;
+  const MDeformVert *origdvert = orig->dvert;
+  int orig_vert_num = orig->totvert;
+  int orig_edge_num = orig->totedge;
 
   /* Get degree of all vertices */
-  degree = MEM_calloc_arrayN(orig_vert_num, sizeof(int), "degree");
+  int *degree = MEM_calloc_arrayN(orig_vert_num, sizeof(int), "degree");
   for (i = 0; i < orig_edge_num; i++) {
     degree[origedge[i].v1]++;
     degree[origedge[i].v2]++;
   }
 
   /* Per edge, store how many subdivisions are needed */
-  edge_subd = MEM_calloc_arrayN((uint)orig_edge_num, sizeof(int), "edge_subd");
+  int *edge_subd = MEM_calloc_arrayN((uint)orig_edge_num, sizeof(int), "edge_subd");
   for (i = 0, subd_num = 0; i < orig_edge_num; i++) {
     edge_subd[i] += calc_edge_subdivisions(origvert, orignode, &origedge[i], degree);
     BLI_assert(edge_subd[i] >= 0);
@@ -918,13 +913,13 @@ static Mesh *subdivide_base(Mesh *orig)
   MEM_freeN(degree);
 
   /* Allocate output mesh */
-  result = BKE_mesh_new_nomain_from_template(
+  Mesh *result = BKE_mesh_new_nomain_from_template(
       orig, orig_vert_num + subd_num, orig_edge_num + subd_num, 0, 0, 0);
 
-  outvert = result->mvert;
-  outedge = result->medge;
-  outnode = CustomData_get_layer(&result->vdata, CD_MVERT_SKIN);
-  outdvert = result->dvert;
+  MVert *outvert = result->mvert;
+  MEdge *outedge = result->medge;
+  MVertSkin *outnode = CustomData_get_layer(&result->vdata, CD_MVERT_SKIN);
+  MDeformVert *outdvert = result->dvert;
 
   /* Copy original vertex data */
   CustomData_copy_data(&orig->vdata, &result->vdata, 0, 0, orig_vert_num);
diff --git a/source/blender/modifiers/intern/MOD_util.c b/source/blender/modifiers/intern/MOD_util.c
index a58e8e23147..575182a846b 100644
--- a/source/blender/modifiers/intern/MOD_util.c
+++ b/source/blender/modifiers/intern/MOD_util.c
@@ -100,10 +100,9 @@ void MOD_get_texture_coords(MappingInfoModifierData *dmd,
       BLI_bitmap *done = BLI_BITMAP_NEW(verts_num, __func__);
       const int polys_num = mesh->totpoly;
       char uvname[MAX_CUSTOMDATA_LAYER_NAME];
-      MLoopUV *mloop_uv;
 
       CustomData_validate_layer_name(&mesh->ldata, CD_MLOOPUV, dmd->uvlayer_name, uvname);
-      mloop_uv = CustomData_get_layer_named(&mesh->ldata, CD_MLOOPUV, uvname);
+      const MLoopUV *mloop_uv = CustomData_get_layer_named(&mesh->ldata, CD_MLOOPUV, uvname);
 
       /* verts are given the UV from the first face that uses them */
       for (i = 0, mp = mpoly; i < polys_num; i++, mp++) {
diff --git a/source/blender/modifiers/intern/MOD_weighted_normal.c b/source/blender/modifiers/intern/MOD_weighted_normal.c
index c79dbdb0b1a..4c06a77e719 100644
--- a/source/blender/modifiers/intern/MOD_weighted_normal.c
+++ b/source/blender/modifiers/intern/MOD_weighted_normal.c
@@ -82,7 +82,7 @@ typedef struct WeightedNormalData {
 
   MPoly *mpoly;
   const float (*polynors)[3];
-  int *poly_strength;
+  const int *poly_strength;
 
   MDeformVert *dvert;
   const int defgrp_index;
@@ -195,7 +195,7 @@ static void apply_weights_vertex_normal(WeightedNormalModifierData *wnmd,
 
   MPoly *mpoly = wn_data->mpoly;
   const float(*polynors)[3] = wn_data->polynors;
-  int *poly_strength = wn_data->poly_strength;
+  const int *poly_strength = wn_data->poly_strength;
 
   MDeformVert *dvert = wn_data->dvert;
 
@@ -603,15 +603,13 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
   }
 
   const float split_angle = mesh->smoothresh;
-  short(*clnors)[2];
-  CustomData *ldata = &result->ldata;
-  clnors = CustomData_get_layer(ldata, CD_CUSTOMLOOPNORMAL);
+  short(*clnors)[2] = CustomData_get_layer(&result->ldata, CD_CUSTOMLOOPNORMAL);
 
   /* Keep info whether we had clnors,
    * it helps when generating clnor spaces and default normals. */
   const bool has_clnors = clnors != NULL;
   if (!clnors) {
-    clnors = CustomData_add_layer(ldata, CD_CUSTOMLOOPNORMAL, CD_CALLOC, NULL, loops_num);
+    clnors = CustomData_add_layer(&result->ldata, CD_CUSTOMLOOPNORMAL, CD_CALLOC, NULL, loops_num);
   }
 
   MDeformVert *dvert;
diff --git a/source/blender/modifiers/intern/MOD_weightvg_util.c b/source/blender/modifiers/intern/MOD_weightvg_util.c
index b251825cd95..acff66e74e4 100644
--- a/source/blender/modifiers/intern/MOD_weightvg_util.c
+++ b/source/blender/modifiers/intern/MOD_weightvg_util.c
@@ -206,8 +206,6 @@ void weightvg_do_mask(const ModifierEvalContext *ctx,
     MEM_freeN(tex_co);
   }
   else if ((ref_didx = BKE_id_defgroup_name_index(&mesh->id, defgrp_name)) != -1) {
-    MDeformVert *dvert = NULL;
-
     /* Check whether we want to set vgroup weights from a constant weight factor or a vertex
      * group.
      */
@@ -215,7 +213,7 @@ void weightvg_do_mask(const ModifierEvalContext *ctx,
 
     /* Proceed only if vgroup is valid, else use constant factor. */
     /* Get actual dverts (ie vertex group data). */
-    dvert = CustomData_get_layer(&mesh->vdata, CD_MDEFORMVERT);
+    const MDeformVert *dvert = CustomData_get_layer(&mesh->vdata, CD_MDEFORMVERT);
     /* Proceed only if vgroup is valid, else assume factor = O. */
     if (dvert == NULL) {
       return;
diff --git a/source/blender/render/intern/bake.c b/source/blender/render/intern/bake.c
index bf876163013..9ffe2879779 100644
--- a/source/blender/render/intern/bake.c
+++ b/source/blender/render/intern/bake.c
@@ -96,7 +96,7 @@ typedef struct TriTessFace {
   const MVert *mverts[3];
   const float *vert_normals[3];
   const TSpace *tspace[3];
-  float *loop_normal[3];
+  const float *loop_normal[3];
   float normal[3]; /* for flat faces */
   bool is_smooth;
 } TriTessFace;
@@ -451,9 +451,6 @@ static bool cast_ray_highpoly(BVHTreeFromMesh *treeData,
 static TriTessFace *mesh_calc_tri_tessface(Mesh *me, bool tangent, Mesh *me_eval)
 {
   int i;
-  MVert *mvert;
-  TSpace *tspace = NULL;
-  float(*loop_normals)[3] = NULL;
 
   const int tottri = poly_to_tri_count(me->totpoly, me->totloop);
   MLoopTri *looptri;
@@ -463,7 +460,7 @@ static TriTessFace *mesh_calc_tri_tessface(Mesh *me, bool tangent, Mesh *me_eval
   unsigned int mpoly_prev = UINT_MAX;
   float no[3];
 
-  mvert = CustomData_get_layer(&me->vdata, CD_MVERT);
+  const MVert *mvert = CustomData_get_layer(&me->vdata, CD_MVERT);
   looptri = MEM_mallocN(sizeof(*looptri) * tottri, __func__);
   triangles = MEM_callocN(sizeof(TriTessFace) * tottri, __func__);
 
@@ -480,6 +477,8 @@ static TriTessFace *mesh_calc_tri_tessface(Mesh *me, bool tangent, Mesh *me_eval
     BKE_mesh_recalc_looptri(me->mloop, me->mpoly, me->mvert, me->totloop, me->totpoly, looptri);
   }
 
+  const TSpace *tspace = NULL;
+  const float(*loop_normals)[3] = NULL;
   if (tangent) {
     BKE_mesh_ensure_normals_for_display(me_eval);
     BKE_mesh_calc_normals_split(me_eval);
diff --git a/source/blender/render/intern/texture_margin.cc b/source/blender/render/intern/texture_margin.cc
index 2d68148a86a..60585789416 100644
--- a/source/blender/render/intern/texture_margin.cc
+++ b/source/blender/render/intern/texture_margin.cc
@@ -492,11 +492,11 @@ static void generate_margin(ImBuf *ibuf,
 
   MPoly *mpoly;
   MLoop *mloop;
-  MLoopUV const *mloopuv;
+  const MLoopUV *mloopuv;
   int totpoly, totloop, totedge;
 
   int tottri;
-  MLoopTri const *looptri;
+  const MLoopTri *looptri;
   MLoopTri *looptri_mem = nullptr;
 
   if (me) {
diff --git a/source/blender/render/intern/texture_pointdensity.c b/source/blender/render/intern/texture_pointdensity.c
index 8ba3bac7cad..b9721f49ce7 100644
--- a/source/blender/render/intern/texture_pointdensity.c
+++ b/source/blender/render/intern/texture_pointdensity.c
@@ -323,13 +323,12 @@ static void pointdensity_cache_vertex_weight(PointDensity *pd,
                                              float *data_color)
 {
   const int totvert = mesh->totvert;
-  const MDeformVert *mdef, *dv;
   int mdef_index;
   int i;
 
   BLI_assert(data_color);
 
-  mdef = CustomData_get_layer(&mesh->vdata, CD_MDEFORMVERT);
+  const MDeformVert *mdef = CustomData_get_layer(&mesh->vdata, CD_MDEFORMVERT);
   if (!mdef) {
     return;
   }
@@ -341,6 +340,7 @@ static void pointdensity_cache_vertex_weight(PointDensity *pd,
     return;
   }
 
+  const MDeformVert *dv;
   for (i = 0, dv = mdef; i < totvert; i++, dv++, data_color += 3) {
     MDeformWeight *dw;
     int j;