virgl: Enable passing arrays as input to fragment shaders

This is needed to properly handle interpolateAt* when the input to be
interpolated is passed as array in the original GLSL.

Currently, the the GLSL compiler would lower selecting the correct input so
that the interpolant parameter to interpolateAt* is a temporary, and this
can not be used to create a valid shader on the host side, because here the
parameter must a shader input.

By allowing the passing the created TGSI allows to create proper GLSL.
This is related to the virglrenderer bug
  https://gitlab.freedesktop.org/virgl/virglrenderer/issues/74

v2: Squash the two patches handling these flags into another

Signed-off-by: Gert Wollny <[email protected]>
Reviewed-by: Gurchetan Singh <[email protected]>

1 files changed, 57 insertions, 7 deletions

diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
index f8771125f45..37e78406c5c 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -2715,6 +2715,42 @@ shrink_array_declarations(struct inout_decl *decls, unsigned count,
    }
 }
 
+
+static void
+mark_array_io(struct inout_decl *decls, unsigned count,
+              GLbitfield64* usage_mask,
+              GLbitfield64 double_usage_mask,
+              GLbitfield* patch_usage_mask)
+{
+   unsigned i;
+   int j;
+
+   /* Fix array declarations by removing unused array elements at both ends
+    * of the arrays. For example, mat4[3] where only mat[1] is used.
+    */
+   for (i = 0; i < count; i++) {
+      struct inout_decl *decl = &decls[i];
+      if (!decl->array_id)
+         continue;
+
+      /* When not all entries of an array are accessed, we mark them as used
+       * here anyway, to ensure that the input/output mapping logic doesn't get
+       * confused.
+       *
+       * TODO This happens when an array isn't used via indirect access, which
+       * some game ports do (at least eON-based). There is an optimization
+       * opportunity here by replacing the array declaration with non-array
+       * declarations of those slots that are actually used.
+       */
+      for (j = 0; j < (int)decl->size; ++j) {
+         if (decl->mesa_index >= VARYING_SLOT_PATCH0)
+            *patch_usage_mask |= BITFIELD64_BIT(decl->mesa_index - VARYING_SLOT_PATCH0 + j);
+         else
+            *usage_mask |= BITFIELD64_BIT(decl->mesa_index + j);
+      }
+   }
+}
+
 void
 glsl_to_tgsi_visitor::visit(ir_dereference_array *ir)
 {
@@ -7157,14 +7193,28 @@ get_mesa_program_tgsi(struct gl_context *ctx,
    }
 
    do_set_program_inouts(shader->ir, prog, shader->Stage);
+
    _mesa_copy_linked_program_data(shader_program, shader);
-   shrink_array_declarations(v->inputs, v->num_inputs,
-                             &prog->info.inputs_read,
-                             prog->DualSlotInputs,
-                             &prog->info.patch_inputs_read);
-   shrink_array_declarations(v->outputs, v->num_outputs,
-                             &prog->info.outputs_written, 0ULL,
-                             &prog->info.patch_outputs_written);
+
+   if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_SKIP_SHRINK_IO_ARRAYS)) {
+      mark_array_io(v->inputs, v->num_inputs,
+                    &prog->info.inputs_read,
+                    prog->DualSlotInputs,
+                    &prog->info.patch_inputs_read);
+
+      mark_array_io(v->outputs, v->num_outputs,
+                    &prog->info.outputs_written, 0ULL,
+                    &prog->info.patch_outputs_written);
+   } else  {
+      shrink_array_declarations(v->inputs, v->num_inputs,
+                                &prog->info.inputs_read,
+                                prog->DualSlotInputs,
+                                &prog->info.patch_inputs_read);
+      shrink_array_declarations(v->outputs, v->num_outputs,
+                                &prog->info.outputs_written, 0ULL,
+                                &prog->info.patch_outputs_written);
+   }
+
    count_resources(v, prog);
 
    /* The GLSL IR won't be needed anymore. */