[Mesa-dev] [PATCH 2/8] Move count_attribute_slots() out of the linker and into glsl_type.

[Paul Berry]

Our previous justification for leaving this function out of glsl_type
was that it implemented counting rules that were specific to GLSL
1.50.  However, these counting rules also describe the number of
varying slots that Mesa will assign to a varying in the absence of
varying packing.  That's useful to be able to compute from outside of
the linker code (a future patch will use it from
ir_set_program_inouts.cpp).  So go ahead and move it to glsl_type.
---
 src/glsl/glsl_types.cpp    | 28 ++++++++++++++++++++++++++++
 src/glsl/glsl_types.h      | 12 ++++++++++++
 src/glsl/link_varyings.cpp |  2 +-
 src/glsl/linker.cpp        | 37 +------------------------------------
 src/glsl/linker.h          |  3 ---
 5 files changed, 42 insertions(+), 40 deletions(-)

diff --git a/src/glsl/glsl_types.cpp b/src/glsl/glsl_types.cpp
index 8324b8a..0c639b3 100644
--- a/src/glsl/glsl_types.cpp
+++ b/src/glsl/glsl_types.cpp
@@ -828,3 +828,31 @@ glsl_type::std140_size(bool row_major) const
    assert(!"not reached");
    return -1;
 }
+
+
+unsigned
+glsl_type::count_attribute_slots() const
+{
+   /* From page 31 (page 37 of the PDF) of the GLSL 1.50 spec:
+    *
+    *     "A scalar input counts the same amount against this limit as a vec4,
+    *     so applications may want to consider packing groups of four
+    *     unrelated float inputs together into a vector to better utilize the
+    *     capabilities of the underlying hardware. A matrix input will use up
+    *     multiple locations.  The number of locations used will equal the
+    *     number of columns in the matrix."
+    *
+    * The spec does not explicitly say how arrays are counted.  However, it
+    * should be safe to assume the total number of slots consumed by an array
+    * is the number of entries in the array multiplied by the number of slots
+    * consumed by a single element of the array.
+    */
+
+   if (this->is_array())
+      return this->array_size() * this->element_type()->count_attribute_slots();
+
+   if (this->is_matrix())
+      return this->matrix_columns;
+
+   return 1;
+}
diff --git a/src/glsl/glsl_types.h b/src/glsl/glsl_types.h
index 8172309..647867a 100644
--- a/src/glsl/glsl_types.h
+++ b/src/glsl/glsl_types.h
@@ -253,6 +253,18 @@ struct glsl_type {
    unsigned component_slots() const;
 
    /**
+    * Calculate the number of attribute slots required to hold this type
+    *
+    * This implements the language rules of GLSL 1.50 for counting the number
+    * of slots used by a vertex attribute.  It also determines the number of
+    * varying slots the type will use up in the absence of varying packing
+    * (and thus, it can be used to measure the number of varying slots used by
+    * the varyings that are generated by lower_packed_varyings).
+    */
+   unsigned count_attribute_slots() const;
+
+
+   /**
     * Alignment in bytes of the start of this type in a std140 uniform
     * block.
     */
diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
index 2c7e451..e3c8142 100644
--- a/src/glsl/link_varyings.cpp
+++ b/src/glsl/link_varyings.cpp
@@ -1164,7 +1164,7 @@ check_against_varying_limit(struct gl_context *ctx,
          /* The packing rules used for vertex shader inputs are also
           * used for fragment shader inputs.
           */
-         varying_vectors += count_attribute_slots(var->type);
+         varying_vectors += var->type->count_attribute_slots();
       }
    }
 
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index 942f906..82075cb 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -298,41 +298,6 @@ link_invalidate_variable_locations(gl_shader *sh, int input_base,
 
 
 /**
- * Determine the number of attribute slots required for a particular type
- *
- * This code is here because it implements the language rules of a specific
- * GLSL version.  Since it's a property of the language and not a property of
- * types in general, it doesn't really belong in glsl_type.
- */
-unsigned
-count_attribute_slots(const glsl_type *t)
-{
-   /* From page 31 (page 37 of the PDF) of the GLSL 1.50 spec:
-    *
-    *     "A scalar input counts the same amount against this limit as a vec4,
-    *     so applications may want to consider packing groups of four
-    *     unrelated float inputs together into a vector to better utilize the
-    *     capabilities of the underlying hardware. A matrix input will use up
-    *     multiple locations.  The number of locations used will equal the
-    *     number of columns in the matrix."
-    *
-    * The spec does not explicitly say how arrays are counted.  However, it
-    * should be safe to assume the total number of slots consumed by an array
-    * is the number of entries in the array multiplied by the number of slots
-    * consumed by a single element of the array.
-    */
-
-   if (t->is_array())
-      return t->array_size() * count_attribute_slots(t->element_type());
-
-   if (t->is_matrix())
-      return t->matrix_columns;
-
-   return 1;
-}
-
-
-/**
  * Verify that a vertex shader executable meets all semantic requirements.
  *
  * Also sets prog->Vert.UsesClipDistance and prog->Vert.ClipDistanceArraySize
@@ -1334,7 +1299,7 @@ assign_attribute_or_color_locations(gl_shader_program *prog,
        * that it doesn't collide with other assigned locations.  Otherwise,
        * add it to the list of variables that need linker-assigned locations.
        */
-      const unsigned slots = count_attribute_slots(var->type);
+      const unsigned slots = var->type->count_attribute_slots();
       if (var->location != -1) {
 	 if (var->location >= generic_base && var->index < 1) {
 	    /* From page 61 of the OpenGL 4.0 spec:
diff --git a/src/glsl/linker.h b/src/glsl/linker.h
index 0ce747d..64a683d 100644
--- a/src/glsl/linker.h
+++ b/src/glsl/linker.h
@@ -155,7 +155,4 @@ linker_error(gl_shader_program *prog, const char *fmt, ...);
 void
 linker_warning(gl_shader_program *prog, const char *fmt, ...);
 
-unsigned
-count_attribute_slots(const glsl_type *t);
-
 #endif /* GLSL_LINKER_H */
-- 
1.8.3.4