Mesa (master): st/glsl_to_tgsi: mark "gaps" in input/output arrays as used

[Nicolai Hähnle]

Module: Mesa
Branch: master
Commit: 2299a9940c5ac5fb42b0726afa9a67fc23ba3a48
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=2299a9940c5ac5fb42b0726afa9a67fc23ba3a48

Author: Nicolai Hähnle <nicolai.haehnle at amd.com>
Date:   Fri Oct  7 21:30:05 2016 +0200

st/glsl_to_tgsi: mark "gaps" in input/output arrays as used

In some cases, a shader may have an input/output array but not use some
entries in the middle. This happens with eON games, for example.

We emit declarations that cover the entire array range even if there are
some unused gaps. This patch now reflects that in the InputsRead etc.
fields to ensure the various input/outputMapping arrays are actually
correct, which will be important when we re-jiggle the way declarations
are emitted.

v2: fix a typo (Edward O'Callaghan)

Reviewed-by: Edward O'Callaghan <funfunctor at folklore1984.net>
Reviewed-by: Dave Airlie <airlied at redhat.com>

---

 src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 32 ++++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
index dc20fe4..0d39fe8 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -2458,9 +2458,9 @@ glsl_to_tgsi_visitor::visit(ir_dereference_variable *ir)
 
 static void
 shrink_array_declarations(struct array_decl *arrays, unsigned count,
-                          GLbitfield64 usage_mask,
+                          GLbitfield64* usage_mask,
                           GLbitfield64 double_usage_mask,
-                          GLbitfield patch_usage_mask)
+                          GLbitfield* patch_usage_mask)
 {
    unsigned i;
    int j;
@@ -2474,12 +2474,12 @@ shrink_array_declarations(struct array_decl *arrays, unsigned count,
       /* Shrink the beginning. */
       for (j = 0; j < (int)decl->array_size; j++) {
          if (decl->mesa_index >= VARYING_SLOT_PATCH0) {
-            if (patch_usage_mask &
+            if (*patch_usage_mask &
                 BITFIELD64_BIT(decl->mesa_index - VARYING_SLOT_PATCH0 + j))
                break;
          }
          else {
-            if (usage_mask & BITFIELD64_BIT(decl->mesa_index+j))
+            if (*usage_mask & BITFIELD64_BIT(decl->mesa_index+j))
                break;
             if (double_usage_mask & BITFIELD64_BIT(decl->mesa_index+j-1))
                break;
@@ -2493,12 +2493,12 @@ shrink_array_declarations(struct array_decl *arrays, unsigned count,
       /* Shrink the end. */
       for (j = decl->array_size-1; j >= 0; j--) {
          if (decl->mesa_index >= VARYING_SLOT_PATCH0) {
-            if (patch_usage_mask &
+            if (*patch_usage_mask &
                 BITFIELD64_BIT(decl->mesa_index - VARYING_SLOT_PATCH0 + j))
                break;
          }
          else {
-            if (usage_mask & BITFIELD64_BIT(decl->mesa_index+j))
+            if (*usage_mask & BITFIELD64_BIT(decl->mesa_index+j))
                break;
             if (double_usage_mask & BITFIELD64_BIT(decl->mesa_index+j-1))
                break;
@@ -2506,6 +2506,22 @@ shrink_array_declarations(struct array_decl *arrays, unsigned count,
 
          decl->array_size--;
       }
+
+      /* 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 = 1; j < (int)decl->array_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);
+      }
    }
 }
 
@@ -6633,9 +6649,9 @@ get_mesa_program_tgsi(struct gl_context *ctx,
 
    do_set_program_inouts(shader->ir, prog, shader->Stage);
    shrink_array_declarations(v->input_arrays, v->num_input_arrays,
-                             prog->InputsRead, prog->DoubleInputsRead, prog->PatchInputsRead);
+                             &prog->InputsRead, prog->DoubleInputsRead, &prog->PatchInputsRead);
    shrink_array_declarations(v->output_arrays, v->num_output_arrays,
-                             prog->OutputsWritten, 0ULL, prog->PatchOutputsWritten);
+                             &prog->OutputsWritten, 0ULL, &prog->PatchOutputsWritten);
    count_resources(v, prog);
 
    /* The GLSL IR won't be needed anymore. */