[Mesa-dev] [PATCH v2 64/82] i965/nir/fs: Implement SSBO atomics

[Iago Toral Quiroga]

---
 src/mesa/drivers/dri/i965/brw_fs.h       |  1 +
 src/mesa/drivers/dri/i965/brw_fs_nir.cpp | 82 ++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index a02912f..b87fef0 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -316,6 +316,7 @@ public:
    void nir_emit_instr(nir_instr *instr);
    void nir_emit_alu(nir_alu_instr *instr);
    void nir_emit_intrinsic(nir_intrinsic_instr *instr);
+   void nir_emit_ssbo_atomic(int op, nir_intrinsic_instr *instr);
    void nir_emit_texture(nir_tex_instr *instr);
    void nir_emit_jump(nir_jump_instr *instr);
    fs_reg get_nir_src(nir_src src);
diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
index 15c1500..36b670b 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
@@ -1719,6 +1719,37 @@ fs_visitor::nir_emit_intrinsic(nir_intrinsic_instr *instr)
       break;
    }
 
+   case nir_intrinsic_ssbo_atomic_add:
+      nir_emit_ssbo_atomic(BRW_AOP_ADD, instr);
+      break;
+   case nir_intrinsic_ssbo_atomic_min:
+      if (dest.type == BRW_REGISTER_TYPE_D)
+         nir_emit_ssbo_atomic(BRW_AOP_IMIN, instr);
+      else
+         nir_emit_ssbo_atomic(BRW_AOP_UMIN, instr);
+      break;
+   case nir_intrinsic_ssbo_atomic_max:
+      if (dest.type == BRW_REGISTER_TYPE_D)
+         nir_emit_ssbo_atomic(BRW_AOP_IMAX, instr);
+      else
+         nir_emit_ssbo_atomic(BRW_AOP_UMAX, instr);
+      break;
+   case nir_intrinsic_ssbo_atomic_and:
+      nir_emit_ssbo_atomic(BRW_AOP_AND, instr);
+      break;
+   case nir_intrinsic_ssbo_atomic_or:
+      nir_emit_ssbo_atomic(BRW_AOP_OR, instr);
+      break;
+   case nir_intrinsic_ssbo_atomic_xor:
+      nir_emit_ssbo_atomic(BRW_AOP_XOR, instr);
+      break;
+   case nir_intrinsic_ssbo_atomic_exchange:
+      nir_emit_ssbo_atomic(BRW_AOP_MOV, instr);
+      break;
+   case nir_intrinsic_ssbo_atomic_comp_swap:
+      nir_emit_ssbo_atomic(BRW_AOP_CMPWR, instr);
+      break;
+
    case nir_intrinsic_ssbo_unsized_array_length: {
       nir_const_value *const_uniform_block = nir_src_as_const_value(instr->src[0]);
       unsigned ubo_index = const_uniform_block ? const_uniform_block->u[0] : 0;
@@ -1776,6 +1807,57 @@ fs_visitor::nir_emit_intrinsic(nir_intrinsic_instr *instr)
 }
 
 void
+fs_visitor::nir_emit_ssbo_atomic(int op, nir_intrinsic_instr *instr)
+{
+   fs_reg dest;
+   if (nir_intrinsic_infos[instr->intrinsic].has_dest)
+      dest = get_nir_dest(instr->dest);
+
+   fs_reg surface;
+   nir_const_value *const_surface = nir_src_as_const_value(instr->src[0]);
+   if (const_surface) {
+      unsigned surf_index = stage_prog_data->binding_table.ubo_start +
+                            const_surface->u[0];
+      surface = fs_reg(surf_index);
+      brw_mark_surface_used(prog_data, surf_index);
+   } else {
+      surface = vgrf(glsl_type::uint_type);
+      emit(ADD(surface, get_nir_src(instr->src[0]),
+               fs_reg(stage_prog_data->binding_table.ubo_start)));
+
+      /* Assume this may touch any UBO. This is the same we do for other
+       * UBO/SSBO accesses with non-constant surface.
+       */
+      brw_mark_surface_used(prog_data,
+                            stage_prog_data->binding_table.ubo_start +
+                            shader_prog->NumUniformBlocks - 1);
+   }
+
+   fs_reg offset = get_nir_src(instr->src[1]);
+   fs_reg data1 = get_nir_src(instr->src[2]);
+   fs_reg data2;
+   if (op == BRW_AOP_CMPWR)
+      data2 = get_nir_src(instr->src[3]);
+
+   /* Emit the actual atomic operation operation */
+   const bool uses_kill = (stage == MESA_SHADER_FRAGMENT &&
+                           ((brw_wm_prog_data *)prog_data)->uses_kill);
+   fs_builder bld(devinfo, mem_ctx, alloc, instructions, dispatch_width,
+                  stage, uses_kill);
+   bld.set_annotation(current_annotation);
+   bld.set_base_ir(base_ir);
+
+   fs_reg atomic_result =
+      surface_access::emit_untyped_atomic(bld, surface, offset,
+                                          data1, data2,
+                                          1 /* dims */, 1 /* rsize */,
+                                          op,
+                                          BRW_PREDICATE_NONE);
+   dest.type = atomic_result.type;
+   emit(MOV(dest, atomic_result));
+}
+
+void
 fs_visitor::nir_emit_texture(nir_tex_instr *instr)
 {
    unsigned sampler = instr->sampler_index;
-- 
1.9.1