FROMLIST: spirv: Use offset_pointer_dereference to instead of get_vulkan_resource_index

There is no good reason why we should have the same logic repeated in
get_vulkan_resource_index and vtn_ssa_offset_pointer_dereference.  If
we're a bit more careful about how we do things, we can just use the one
function and get rid of the other entirely.  This also makes the push
constant special case a lot more clear.

Archived-At: https://lists.freedesktop.org/archives/mesa-dev/2017-October/173535.html
(am from https://patchwork.freedesktop.org/patch/183828/)

Needed for SPIR-V VariablePointers capability.

BUG=b:68708929
TEST=No regressions on Eve in `cts-tradefed run cts -m CtsDeqpTestCases`.

Change-Id: I338bf2214e916c779b86628c684e434ece81b4a5
Reviewed-on: https://chromium-review.googlesource.com/799677
Tested-by: Chad Versace <chadversary@chromium.org>
Reviewed-by: Kristian H. Kristensen <hoegsberg@chromium.org>
Commit-Queue: Kristian H. Kristensen <hoegsberg@chromium.org>

1 files changed, 21 insertions, 35 deletions

diff --git a/src/compiler/spirv/vtn_variables.c b/src/compiler/spirv/vtn_variables.c
index ed5002b3390..2c952cd478e 100644
--- a/src/compiler/spirv/vtn_variables.c
+++ b/src/compiler/spirv/vtn_variables.c
@@ -503,45 +503,27 @@ vtn_local_store(struct vtn_builder *b, struct vtn_ssa_value *src,
    }
 }
 
-static nir_ssa_def *
-get_vulkan_resource_index(struct vtn_builder *b, struct vtn_pointer *ptr,
-                          struct vtn_type **type, unsigned *chain_idx)
-{
-   /* Push constants have no explicit binding */
-   if (ptr->mode == vtn_variable_mode_push_constant) {
-      *chain_idx = 0;
-      *type = ptr->var->type;
-      return NULL;
-   }
-
-   if (glsl_type_is_array(ptr->var->type->type)) {
-      assert(ptr->chain->length > 0);
-      nir_ssa_def *desc_array_index =
-         vtn_access_link_as_ssa(b, ptr->chain->link[0], 1);
-      *chain_idx = 1;
-      *type = ptr->var->type->array_element;
-      return vtn_variable_resource_index(b, ptr->var, desc_array_index);
-   } else {
-      *chain_idx = 0;
-      *type = ptr->var->type;
-      return vtn_variable_resource_index(b, ptr->var, NULL);
-   }
-}
-
 nir_ssa_def *
 vtn_pointer_to_offset(struct vtn_builder *b, struct vtn_pointer *ptr,
                       nir_ssa_def **index_out, unsigned *end_idx_out)
 {
-   if (ptr->offset) {
-      assert(ptr->block_index);
+   if (vtn_pointer_uses_ssa_offset(b, ptr)) {
+      if (!ptr->offset) {
+         assert(ptr->mode == vtn_variable_mode_workgroup);
+         struct vtn_access_chain chain = {
+            .length = 0,
+         };
+         ptr = vtn_ssa_offset_pointer_dereference(b, ptr, &chain);
+      }
       *index_out = ptr->block_index;
       return ptr->offset;
    }
 
-   unsigned idx = 0;
-   struct vtn_type *type;
-   *index_out = get_vulkan_resource_index(b, ptr, &type, &idx);
+   assert(ptr->mode == vtn_variable_mode_push_constant);
+   *index_out = NULL;
 
+   unsigned idx = 0;
+   struct vtn_type *type = ptr->var->type;
    nir_ssa_def *offset = nir_imm_int(&b->nb, 0);
    for (; idx < ptr->chain->length; idx++) {
       enum glsl_base_type base_type = glsl_get_base_type(type->type);
@@ -1895,15 +1877,19 @@ vtn_handle_variables(struct vtn_builder *b, SpvOp opcode,
       const uint32_t offset = ptr->var->type->offsets[w[4]];
       const uint32_t stride = ptr->var->type->members[w[4]]->stride;
 
-      unsigned chain_idx;
-      struct vtn_type *type;
-      nir_ssa_def *index =
-         get_vulkan_resource_index(b, ptr, &type, &chain_idx);
+      if (!ptr->block_index) {
+         assert(ptr->mode == vtn_variable_mode_workgroup);
+         struct vtn_access_chain chain = {
+            .length = 0,
+         };
+         ptr = vtn_ssa_offset_pointer_dereference(b, ptr, &chain);
+         assert(ptr->block_index);
+      }
 
       nir_intrinsic_instr *instr =
          nir_intrinsic_instr_create(b->nb.shader,
                                     nir_intrinsic_get_buffer_size);
-      instr->src[0] = nir_src_for_ssa(index);
+      instr->src[0] = nir_src_for_ssa(ptr->block_index);
       nir_ssa_dest_init(&instr->instr, &instr->dest, 1, 32, NULL);
       nir_builder_instr_insert(&b->nb, &instr->instr);
       nir_ssa_def *buf_size = &instr->dest.ssa;