[Mesa-dev] [PATCH] st/nir: fix atomic lowering for gallium drivers

[Timothy Arceri]

i965 and gallium handle the atomic buffer index differently. It was
just by luck that the single piglit test for this was passing.

For gallium we use the atomic binding so that we match the handling
in st_bind_atomics().

On radeonsi this fixes the CTS test:
KHR-GL43.shader_storage_buffer_object.advanced-write-fragment

It also fixes tressfx hair rendering in Tomb Raider.
---
 src/compiler/nir/nir.h                    |  3 ++-
 src/compiler/nir/nir_lower_atomics.c      | 15 ++++++++++-----
 src/mesa/drivers/dri/i965/brw_link.cpp    |  2 +-
 src/mesa/state_tracker/st_glsl_to_nir.cpp |  2 +-
 4 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index e7a8afcad1..06f8a1076f 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -2716,7 +2716,8 @@ typedef struct nir_lower_bitmap_options {
 void nir_lower_bitmap(nir_shader *shader, const nir_lower_bitmap_options *options);
 
 bool nir_lower_atomics(nir_shader *shader,
-                       const struct gl_shader_program *shader_program);
+                       const struct gl_shader_program *shader_program,
+                       bool use_binding_as_idx);
 bool nir_lower_atomics_to_ssbo(nir_shader *shader, unsigned ssbo_offset);
 bool nir_lower_to_source_mods(nir_shader *shader);
 
diff --git a/src/compiler/nir/nir_lower_atomics.c b/src/compiler/nir/nir_lower_atomics.c
index bdab4b8737..6b046bc426 100644
--- a/src/compiler/nir/nir_lower_atomics.c
+++ b/src/compiler/nir/nir_lower_atomics.c
@@ -38,7 +38,7 @@
 static bool
 lower_instr(nir_intrinsic_instr *instr,
             const struct gl_shader_program *shader_program,
-            nir_shader *shader)
+            nir_shader *shader, bool use_binding_as_idx)
 {
    nir_intrinsic_op op;
    switch (instr->intrinsic) {
@@ -98,9 +98,12 @@ lower_instr(nir_intrinsic_instr *instr,
    void *mem_ctx = ralloc_parent(instr);
    unsigned uniform_loc = instr->variables[0]->var->data.location;
 
+   unsigned idx = use_binding_as_idx ?
+      instr->variables[0]->var->data.binding :
+      shader_program->data->UniformStorage[uniform_loc].opaque[shader->info.stage].index;
+
    nir_intrinsic_instr *new_instr = nir_intrinsic_instr_create(mem_ctx, op);
-   nir_intrinsic_set_base(new_instr,
-      shader_program->data->UniformStorage[uniform_loc].opaque[shader->info.stage].index);
+   nir_intrinsic_set_base(new_instr, idx);
 
    nir_load_const_instr *offset_const =
       nir_load_const_instr_create(mem_ctx, 1, 32);
@@ -174,7 +177,8 @@ lower_instr(nir_intrinsic_instr *instr,
 
 bool
 nir_lower_atomics(nir_shader *shader,
-                  const struct gl_shader_program *shader_program)
+                  const struct gl_shader_program *shader_program,
+                  bool use_binding_as_idx)
 {
    bool progress = false;
 
@@ -184,7 +188,8 @@ nir_lower_atomics(nir_shader *shader,
             nir_foreach_instr_safe(instr, block) {
                if (instr->type == nir_instr_type_intrinsic)
                   progress |= lower_instr(nir_instr_as_intrinsic(instr),
-                                          shader_program, shader);
+                                          shader_program, shader,
+                                          use_binding_as_idx);
             }
          }
 
diff --git a/src/mesa/drivers/dri/i965/brw_link.cpp b/src/mesa/drivers/dri/i965/brw_link.cpp
index b08b56a935..274a738cbb 100644
--- a/src/mesa/drivers/dri/i965/brw_link.cpp
+++ b/src/mesa/drivers/dri/i965/brw_link.cpp
@@ -299,7 +299,7 @@ brw_link_shader(struct gl_context *ctx, struct gl_shader_program *shProg)
       brw_shader_gather_info(prog->nir, prog);
 
       NIR_PASS_V(prog->nir, nir_lower_samplers, shProg);
-      NIR_PASS_V(prog->nir, nir_lower_atomics, shProg);
+      NIR_PASS_V(prog->nir, nir_lower_atomics, shProg, false);
       NIR_PASS_V(prog->nir, nir_lower_atomics_to_ssbo,
                  prog->nir->info.num_abos);
 
diff --git a/src/mesa/state_tracker/st_glsl_to_nir.cpp b/src/mesa/state_tracker/st_glsl_to_nir.cpp
index 6f3fa248f1..fb45cf2d5e 100644
--- a/src/mesa/state_tracker/st_glsl_to_nir.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_nir.cpp
@@ -428,7 +428,7 @@ st_glsl_to_nir_post_opts(struct st_context *st, struct gl_program *prog,
    st_set_prog_affected_state_flags(prog);
 
    NIR_PASS_V(nir, st_nir_lower_builtin);
-   NIR_PASS_V(nir, nir_lower_atomics, shader_program);
+   NIR_PASS_V(nir, nir_lower_atomics, shader_program, true);
 
    if (st->ctx->_Shader->Flags & GLSL_DUMP) {
       _mesa_log("\n");
-- 
2.14.3