Mesa (master): glsl: Accept nonconstant array references in lower_ubo_reference

[Chris Forbes]

Module: Mesa
Branch: master
Commit: be237a61297936227b2f4afc2ac28f60c3c76bbf
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=be237a61297936227b2f4afc2ac28f60c3c76bbf

Author: Chris Forbes <chrisf at ijw.co.nz>
Date:   Fri May 16 22:07:24 2014 +1200

glsl: Accept nonconstant array references in lower_ubo_reference

Instead of falling back to just the block name (which we won't find),
look for the first element of the block array. We'll deal with the rest
in the backend by arranging for the blocks to be laid out contiguously.

V2: Squashed together patches 3, 5 of V1, plus a naming tweak.

Signed-off-by: Chris Forbes <chrisf at ijw.co.nz>
Reviewed-by: Ilia Mirkin <imirkin at alum.mit.edu>
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

---

 src/glsl/lower_ubo_reference.cpp |   43 ++++++++++++++++++++++++++++----------
 1 file changed, 32 insertions(+), 11 deletions(-)

diff --git a/src/glsl/lower_ubo_reference.cpp b/src/glsl/lower_ubo_reference.cpp
index 9729ea0..67b752d 100644
--- a/src/glsl/lower_ubo_reference.cpp
+++ b/src/glsl/lower_ubo_reference.cpp
@@ -69,9 +69,11 @@ public:
  * \c UniformBlocks array.
  */
 static const char *
-interface_field_name(void *mem_ctx, char *base_name, ir_dereference *d)
+interface_field_name(void *mem_ctx, char *base_name, ir_dereference *d,
+                     ir_rvalue **nonconst_block_index)
 {
-   ir_constant *previous_index = NULL;
+   ir_rvalue *previous_index = NULL;
+   *nonconst_block_index = NULL;
 
    while (d != NULL) {
       switch (d->ir_type) {
@@ -79,13 +81,21 @@ interface_field_name(void *mem_ctx, char *base_name, ir_dereference *d)
          ir_dereference_variable *v = (ir_dereference_variable *) d;
          if (previous_index
              && v->var->is_interface_instance()
-             && v->var->type->is_array())
-            return ralloc_asprintf(mem_ctx,
-                                   "%s[%d]",
-                                   base_name,
-                                   previous_index->get_uint_component(0));
-         else
+             && v->var->type->is_array()) {
+
+            ir_constant *const_index = previous_index->as_constant();
+            if (!const_index) {
+               *nonconst_block_index = previous_index;
+               return ralloc_asprintf(mem_ctx, "%s[0]", base_name);
+            } else {
+               return ralloc_asprintf(mem_ctx,
+                                      "%s[%d]",
+                                      base_name,
+                                      const_index->get_uint_component(0));
+            }
+         } else {
             return base_name;
+         }
 
          break;
       }
@@ -101,7 +111,8 @@ interface_field_name(void *mem_ctx, char *base_name, ir_dereference *d)
          ir_dereference_array *a = (ir_dereference_array *) d;
 
          d = a->array->as_dereference();
-         previous_index = a->array_index->as_constant();
+         previous_index = a->array_index;
+
          break;
       }
 
@@ -131,14 +142,24 @@ lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
 
    mem_ctx = ralloc_parent(*rvalue);
 
+   ir_rvalue *nonconst_block_index;
    const char *const field_name =
       interface_field_name(mem_ctx, (char *) var->get_interface_type()->name,
-                           deref);
+                           deref, &nonconst_block_index);
 
    this->uniform_block = NULL;
    for (unsigned i = 0; i < shader->NumUniformBlocks; i++) {
       if (strcmp(field_name, shader->UniformBlocks[i].Name) == 0) {
-         this->uniform_block = new(mem_ctx) ir_constant(i);
+
+         ir_constant *index = new(mem_ctx) ir_constant(i);
+
+         if (nonconst_block_index) {
+            if (nonconst_block_index->type != glsl_type::uint_type)
+               nonconst_block_index = i2u(nonconst_block_index);
+            this->uniform_block = add(nonconst_block_index, index);
+         } else {
+            this->uniform_block = index;
+         }
 
          struct gl_uniform_block *block = &shader->UniformBlocks[i];