[Mesa-dev] [PATCH] gallium/ttn: mark location specially in nir for color0-writes-all

[Ilia Mirkin]

We need to distinguish a shader that has separate writes to each MRT
from one which is supposed to write the data from MRT 0 to all the MRTs.
In TGSI this is done with a property. NIR doesn't have that, so encode
it as a funny location and decode on the other end.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---

This fixes bin/fbo-drawbuffers-none gl_FragColor when I additionally
initialize the "default" colors to a register other than r0.x -- as is
this happens to work by luck.

Also fix up vc4 to ignore this for now.

 src/gallium/auxiliary/nir/tgsi_to_nir.c              | 7 ++++++-
 src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c | 4 ++++
 src/gallium/drivers/vc4/vc4_program.c                | 6 ++++++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/gallium/auxiliary/nir/tgsi_to_nir.c b/src/gallium/auxiliary/nir/tgsi_to_nir.c
index bf7eb2f..4130697 100644
--- a/src/gallium/auxiliary/nir/tgsi_to_nir.c
+++ b/src/gallium/auxiliary/nir/tgsi_to_nir.c
@@ -253,7 +253,12 @@ ttn_emit_declaration(struct ttn_compile *c)
             var->name = ralloc_asprintf(var, "out_%d", idx);
 
             var->data.location = decl->Semantic.Name;
-            var->data.index = decl->Semantic.Index;
+            if (decl->Semantic.Name == TGSI_SEMANTIC_COLOR &&
+                decl->Semantic.Index == 0 &&
+                c->scan->properties[TGSI_PROPERTY_FS_COLOR0_WRITES_ALL_CBUFS])
+               var->data.index = -1;
+            else
+               var->data.index = decl->Semantic.Index;
 
             if (is_array) {
                unsigned j;
diff --git a/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c b/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
index 3b36114..fa13c40 100644
--- a/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
+++ b/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
@@ -2110,6 +2110,10 @@ setup_output(struct ir3_compile *ctx, nir_variable *out)
 			so->writes_pos = true;
 			break;
 		case TGSI_SEMANTIC_COLOR:
+			if (semantic_index == -1) {
+				semantic_index = 0;
+				so->color0_mrt = 1;
+			}
 			break;
 		default:
 			compile_error(ctx, "unknown FS semantic name: %s\n",
diff --git a/src/gallium/drivers/vc4/vc4_program.c b/src/gallium/drivers/vc4/vc4_program.c
index 2061631..728ecc6 100644
--- a/src/gallium/drivers/vc4/vc4_program.c
+++ b/src/gallium/drivers/vc4/vc4_program.c
@@ -1783,6 +1783,12 @@ ntq_setup_outputs(struct vc4_compile *c)
 
                 assert(array_len == 1);
 
+                /* NIR hack to pass through
+                 * TGSI_PROPERTY_FS_COLOR0_WRITES_ALL_CBUFS */
+                if (semantic_name == TGSI_SEMANTIC_COLOR &&
+                    semantic_index == -1)
+                        semantic_index = 0;
+
                 for (int i = 0; i < 4; i++) {
                         add_output(c,
                                    loc + i,
-- 
2.3.6