glsl: fix recording of variables for XFB in TCS shaders

This is purely for conformance, since it's not actually possible to do
XFB on TCS output varyings. However we do have to make sure we record
the names correctly, and this removes an extra level of array-ness from
the names in question.

Fixes KHR-GL45.tessellation_shader.single.xfb_captures_data_from_correct_stage

v2: Add comment to the new program_resource_visitor::process function.
    (Ilia Mirkin)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108457
Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Cc: 19.0 <mesa-stable@lists.freedesktop.org>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>

src/compiler/glsl/link_uniforms.cpp

@@ -62,6 +62,15 @@ program_resource_visitor::process(const glsl_type *type, const char *name,
 
 void
 program_resource_visitor::process(ir_variable *var, bool use_std430_as_default)
+{
+   const glsl_type *t =
+      var->data.from_named_ifc_block ? var->get_interface_type() : var->type;
+   process(var, t, use_std430_as_default);
+}
+
+void
+program_resource_visitor::process(ir_variable *var, const glsl_type *var_type,
+                                  bool use_std430_as_default)
 {
    unsigned record_array_count = 1;
    const bool row_major =
@@ -72,8 +81,7 @@ program_resource_visitor::process(ir_variable *var, bool use_std430_as_default)
          get_internal_ifc_packing(use_std430_as_default) :
       var->type->get_internal_ifc_packing(use_std430_as_default);
 
-   const glsl_type *t =
-      var->data.from_named_ifc_block ? var->get_interface_type() : var->type;
+   const glsl_type *t = var_type;
    const glsl_type *t_without_array = t->without_array();
 
    /* false is always passed for the row_major parameter to the other

src/compiler/glsl/link_varyings.cpp

@@ -2124,9 +2124,11 @@ class tfeedback_candidate_generator : public program_resource_visitor
 {
 public:
    tfeedback_candidate_generator(void *mem_ctx,
-                                 hash_table *tfeedback_candidates)
+                                 hash_table *tfeedback_candidates,
+                                 gl_shader_stage stage)
       : mem_ctx(mem_ctx),
         tfeedback_candidates(tfeedback_candidates),
+        stage(stage),
         toplevel_var(NULL),
         varying_floats(0)
    {
@@ -2136,10 +2138,17 @@ public:
    {
       /* All named varying interface blocks should be flattened by now */
       assert(!var->is_interface_instance());
+      assert(var->data.mode == ir_var_shader_out);
 
       this->toplevel_var = var;
       this->varying_floats = 0;
-      program_resource_visitor::process(var, false);
+      const glsl_type *t =
+         var->data.from_named_ifc_block ? var->get_interface_type() : var->type;
+      if (!var->data.patch && stage == MESA_SHADER_TESS_CTRL) {
+         assert(t->is_array());
+         t = t->fields.array;
+      }
+      program_resource_visitor::process(var, t, false);
    }
 
 private:
@@ -2173,6 +2182,8 @@ private:
     */
    hash_table * const tfeedback_candidates;
 
+   gl_shader_stage stage;
+
    /**
     * Pointer to the toplevel variable that is being traversed.
     */
@@ -2503,7 +2514,7 @@ assign_varying_locations(struct gl_context *ctx,
                  producer->Stage == MESA_SHADER_GEOMETRY));
 
          if (num_tfeedback_decls > 0) {
-            tfeedback_candidate_generator g(mem_ctx, tfeedback_candidates);
+            tfeedback_candidate_generator g(mem_ctx, tfeedback_candidates, producer->Stage);
             /* From OpenGL 4.6 (Core Profile) spec, section 11.1.2.1
              * ("Vertex Shader Variables / Output Variables")
              *

src/compiler/glsl/linker.h

@@ -134,6 +134,26 @@ public:
     */
    void process(ir_variable *var, bool use_std430_as_default);
 
+   /**
+    * Begin processing a variable
+    *
+    * Classes that overload this function should call \c ::process from the
+    * base class to start the recursive processing of the variable.
+    *
+    * \param var  The variable that is to be processed
+    * \param var_type The glsl_type reference of the variable
+    *
+    * Calls \c ::visit_field for each leaf of the variable.
+    *
+    * \warning
+    * When processing a uniform block, this entry should only be used in cases
+    * where the row / column ordering of matrices in the block does not
+    * matter.  For example, enumerating the names of members of the block, but
+    * not for determining the offsets of members.
+    */
+   void process(ir_variable *var, const glsl_type *var_type,
+                bool use_std430_as_default);
+
    /**
     * Begin processing a variable of a structured type.
     *