i965: make use of nir linking
[mesa.git] / src / mesa / drivers / dri / i965 / brw_link.cpp
index 871a2fc1a9a5d2ad1c7d672b7bbc1294381f3a7c..9ddf023018370aeed130062a60f8233f04a8b56e 100644 (file)
  */
 
 #include "brw_context.h"
-#include "brw_shader.h"
-#include "brw_fs.h"
-#include "brw_nir.h"
+#include "compiler/brw_nir.h"
 #include "brw_program.h"
 #include "compiler/glsl/ir.h"
 #include "compiler/glsl/ir_optimization.h"
 #include "compiler/glsl/program.h"
 #include "program/program.h"
+#include "main/mtypes.h"
 #include "main/shaderapi.h"
 #include "main/shaderobj.h"
 #include "main/uniforms.h"
@@ -50,10 +49,10 @@ brw_shader_precompile(struct gl_context *ctx,
    struct gl_linked_shader *fs = sh_prog->_LinkedShaders[MESA_SHADER_FRAGMENT];
    struct gl_linked_shader *cs = sh_prog->_LinkedShaders[MESA_SHADER_COMPUTE];
 
-   if (fs && !brw_fs_precompile(ctx, sh_prog, fs->Program))
+   if (fs && !brw_fs_precompile(ctx, fs->Program))
       return false;
 
-   if (gs && !brw_gs_precompile(ctx, sh_prog, gs->Program))
+   if (gs && !brw_gs_precompile(ctx, gs->Program))
       return false;
 
    if (tes && !brw_tes_precompile(ctx, sh_prog, tes->Program))
@@ -62,10 +61,10 @@ brw_shader_precompile(struct gl_context *ctx,
    if (tcs && !brw_tcs_precompile(ctx, sh_prog, tcs->Program))
       return false;
 
-   if (vs && !brw_vs_precompile(ctx, sh_prog, vs->Program))
+   if (vs && !brw_vs_precompile(ctx, vs->Program))
       return false;
 
-   if (cs && !brw_cs_precompile(ctx, sh_prog, cs->Program))
+   if (cs && !brw_cs_precompile(ctx, cs->Program))
       return false;
 
    return true;
@@ -75,10 +74,12 @@ static void
 brw_lower_packing_builtins(struct brw_context *brw,
                            exec_list *ir)
 {
+   const struct gen_device_info *devinfo = &brw->screen->devinfo;
+
    /* Gens < 7 don't have instructions to convert to or from half-precision,
     * and Gens < 6 don't expose that functionality.
     */
-   if (brw->gen != 6)
+   if (devinfo->gen != 6)
       return;
 
    lower_packing_builtins(ir, LOWER_PACK_HALF_2x16 | LOWER_UNPACK_HALF_2x16);
@@ -89,10 +90,8 @@ process_glsl_ir(struct brw_context *brw,
                 struct gl_shader_program *shader_prog,
                 struct gl_linked_shader *shader)
 {
+   const struct gen_device_info *devinfo = &brw->screen->devinfo;
    struct gl_context *ctx = &brw->ctx;
-   const struct brw_compiler *compiler = brw->screen->compiler;
-   const struct gl_shader_compiler_options *options =
-      &ctx->Const.ShaderCompilerOptions[shader->Stage];
 
    /* Temporary memory context for any new IR. */
    void *mem_ctx = ralloc_context(NULL);
@@ -112,7 +111,7 @@ process_glsl_ir(struct brw_context *brw,
                                      EXP_TO_EXP2 |
                                      LOG_TO_LOG2 |
                                      DFREXP_DLDEXP_TO_ARITH);
-   if (brw->gen < 7) {
+   if (devinfo->gen < 7) {
       instructions_to_lower |= BIT_COUNT_TO_MATH |
                                EXTRACT_TO_SHIFTS |
                                INSERT_TO_SHIFTS |
@@ -124,53 +123,16 @@ process_glsl_ir(struct brw_context *brw,
    /* Pre-gen6 HW can only nest if-statements 16 deep.  Beyond this,
     * if-statements need to be flattened.
     */
-   if (brw->gen < 6)
+   if (devinfo->gen < 6)
       lower_if_to_cond_assign(shader->Stage, shader->ir, 16);
 
    do_lower_texture_projection(shader->ir);
-   brw_lower_texture_gradients(brw, shader->ir);
    do_vec_index_to_cond_assign(shader->ir);
    lower_vector_insert(shader->ir, true);
    lower_offset_arrays(shader->ir);
    lower_noise(shader->ir);
    lower_quadop_vector(shader->ir, false);
 
-   do_copy_propagation(shader->ir);
-
-   bool lowered_variable_indexing =
-      lower_variable_index_to_cond_assign(shader->Stage, shader->ir,
-                                          options->EmitNoIndirectInput,
-                                          options->EmitNoIndirectOutput,
-                                          options->EmitNoIndirectTemp,
-                                          options->EmitNoIndirectUniform);
-
-   if (unlikely(brw->perf_debug && lowered_variable_indexing)) {
-      perf_debug("Unsupported form of variable indexing in %s; falling "
-                 "back to very inefficient code generation\n",
-                 _mesa_shader_stage_to_abbrev(shader->Stage));
-   }
-
-   bool progress;
-   do {
-      progress = false;
-
-      if (compiler->scalar_stage[shader->Stage]) {
-         if (shader->Stage == MESA_SHADER_VERTEX ||
-             shader->Stage == MESA_SHADER_FRAGMENT)
-            brw_do_channel_expressions(shader->ir);
-         brw_do_vector_splitting(shader->ir);
-      }
-
-      progress = do_lower_jumps(shader->ir, true, true,
-                                true, /* main return */
-                                false, /* continue */
-                                false /* loops */
-                                ) || progress;
-
-      progress = do_common_optimization(shader->ir, true, true,
-                                        options, ctx->Const.NativeIntegers) || progress;
-   } while (progress);
-
    validate_ir_tree(shader->ir);
 
    /* Now that we've finished altering the linked IR, reparent any live IR back
@@ -196,19 +158,6 @@ process_glsl_ir(struct brw_context *brw,
    }
 }
 
-extern "C" struct gl_linked_shader *
-brw_new_shader(gl_shader_stage stage)
-{
-   struct brw_shader *shader;
-
-   shader = rzalloc(NULL, struct brw_shader);
-   if (shader) {
-      shader->base.Stage = stage;
-   }
-
-   return &shader->base;
-}
-
 static void
 unify_interfaces(struct shader_info **infos)
 {
@@ -219,15 +168,54 @@ unify_interfaces(struct shader_info **infos)
          continue;
 
       if (prev_info) {
-         prev_info->outputs_written |= infos[i]->inputs_read;
+         prev_info->outputs_written |= infos[i]->inputs_read &
+            ~(VARYING_BIT_TESS_LEVEL_INNER | VARYING_BIT_TESS_LEVEL_OUTER);
+         infos[i]->inputs_read |= prev_info->outputs_written &
+            ~(VARYING_BIT_TESS_LEVEL_INNER | VARYING_BIT_TESS_LEVEL_OUTER);
+
          prev_info->patch_outputs_written |= infos[i]->patch_inputs_read;
-         infos[i]->inputs_read |= prev_info->outputs_written;
          infos[i]->patch_inputs_read |= prev_info->patch_outputs_written;
       }
       prev_info = infos[i];
    }
 }
 
+static void
+update_xfb_info(struct gl_transform_feedback_info *xfb_info,
+                struct shader_info *info)
+{
+   if (!xfb_info)
+      return;
+
+   for (unsigned i = 0; i < xfb_info->NumOutputs; i++) {
+      struct gl_transform_feedback_output *output = &xfb_info->Outputs[i];
+
+      /* The VUE header contains three scalar fields packed together:
+       * - gl_PointSize is stored in VARYING_SLOT_PSIZ.w
+       * - gl_Layer is stored in VARYING_SLOT_PSIZ.y
+       * - gl_ViewportIndex is stored in VARYING_SLOT_PSIZ.z
+       */
+      switch (output->OutputRegister) {
+      case VARYING_SLOT_LAYER:
+         assert(output->NumComponents == 1);
+         output->OutputRegister = VARYING_SLOT_PSIZ;
+         output->ComponentOffset = 1;
+         break;
+      case VARYING_SLOT_VIEWPORT:
+         assert(output->NumComponents == 1);
+         output->OutputRegister = VARYING_SLOT_PSIZ;
+         output->ComponentOffset = 2;
+         break;
+      case VARYING_SLOT_PSIZ:
+         assert(output->NumComponents == 1);
+         output->ComponentOffset = 3;
+         break;
+      }
+
+      info->outputs_written |= 1ull << output->OutputRegister;
+   }
+}
+
 extern "C" GLboolean
 brw_link_shader(struct gl_context *ctx, struct gl_shader_program *shProg)
 {
@@ -248,35 +236,9 @@ brw_link_shader(struct gl_context *ctx, struct gl_shader_program *shProg)
 
       _mesa_copy_linked_program_data(shProg, shader);
 
-      /* Make a pass over the IR to add state references for any built-in
-       * uniforms that are used.  This has to be done now (during linking).
-       * Code generation doesn't happen until the first time this shader is
-       * used for rendering.  Waiting until then to generate the parameters is
-       * too late.  At that point, the values for the built-in uniforms won't
-       * get sent to the shader.
-       */
-      foreach_in_list(ir_instruction, node, shader->ir) {
-         ir_variable *var = node->as_variable();
-
-         if ((var == NULL) || (var->data.mode != ir_var_uniform)
-             || (strncmp(var->name, "gl_", 3) != 0))
-            continue;
-
-         const ir_state_slot *const slots = var->get_state_slots();
-         assert(slots != NULL);
-
-         for (unsigned int i = 0; i < var->get_num_state_slots(); i++) {
-            _mesa_add_state_reference(prog->Parameters,
-                                      (gl_state_index *) slots[i].tokens);
-         }
-      }
-
-      prog->SamplersUsed = shader->active_samplers;
       prog->ShadowSamplers = shader->shadow_samplers;
       _mesa_update_shader_textures_used(shProg, prog);
 
-      brw_add_texrect_params(prog);
-
       bool debug_enabled =
          (INTEL_DEBUG & intel_debug_flag_for_shader_stage(shader->Stage));
 
@@ -289,7 +251,98 @@ brw_link_shader(struct gl_context *ctx, struct gl_shader_program *shProg)
 
       prog->nir = brw_create_nir(brw, shProg, prog, (gl_shader_stage) stage,
                                  compiler->scalar_stage[stage]);
-      infos[stage] = prog->nir->info;
+   }
+
+   /* Determine first and last stage. */
+   unsigned first = MESA_SHADER_STAGES;
+   unsigned last = 0;
+   for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
+      if (!shProg->_LinkedShaders[i])
+         continue;
+      if (first == MESA_SHADER_STAGES)
+         first = i;
+      last = i;
+   }
+
+   /* Linking the stages in the opposite order (from fragment to vertex)
+    * ensures that inter-shader outputs written to in an earlier stage
+    * are eliminated if they are (transitively) not used in a later
+    * stage.
+    */
+    if (first != last) {
+       int next = last;
+       for (int i = next - 1; i >= 0; i--) {
+          if (shProg->_LinkedShaders[i] == NULL)
+             continue;
+
+            nir_shader *producer = shProg->_LinkedShaders[i]->Program->nir;
+            nir_shader *consumer = shProg->_LinkedShaders[next]->Program->nir;
+
+            nir_remove_dead_variables(producer, nir_var_shader_out);
+            nir_remove_dead_variables(consumer, nir_var_shader_in);
+
+            if (nir_remove_unused_varyings(producer, consumer)) {
+               nir_lower_global_vars_to_local(producer);
+               nir_lower_global_vars_to_local(consumer);
+
+               nir_variable_mode indirect_mask = (nir_variable_mode) 0;
+               if (compiler->glsl_compiler_options[i].EmitNoIndirectTemp)
+                  indirect_mask = (nir_variable_mode) nir_var_local;
+
+               /* The backend might not be able to handle indirects on
+                * temporaries so we need to lower indirects on any of the
+                * varyings we have demoted here.
+                */
+               nir_lower_indirect_derefs(producer, indirect_mask);
+               nir_lower_indirect_derefs(consumer, indirect_mask);
+
+               const bool p_is_scalar = compiler->scalar_stage[producer->stage];
+               shProg->_LinkedShaders[i]->Program->nir =
+                 brw_nir_optimize(producer, compiler, p_is_scalar);
+
+               const bool c_is_scalar = compiler->scalar_stage[producer->stage];
+               shProg->_LinkedShaders[next]->Program->nir =
+                 brw_nir_optimize(consumer, compiler, c_is_scalar);
+            }
+
+            next = i;
+       }
+    }
+
+   for (stage = 0; stage < ARRAY_SIZE(shProg->_LinkedShaders); stage++) {
+      struct gl_linked_shader *shader = shProg->_LinkedShaders[stage];
+      if (!shader)
+         continue;
+
+      struct gl_program *prog = shader->Program;
+      nir_shader *nir = shader->Program->nir;
+      brw_shader_gather_info(nir, prog);
+
+      NIR_PASS_V(nir, nir_lower_samplers, shProg);
+      NIR_PASS_V(nir, nir_lower_atomics, shProg);
+
+      infos[stage] = &prog->nir->info;
+
+      update_xfb_info(prog->sh.LinkedTransformFeedback, infos[stage]);
+
+      /* Make a pass over the IR to add state references for any built-in
+       * uniforms that are used.  This has to be done now (during linking).
+       * Code generation doesn't happen until the first time this shader is
+       * used for rendering.  Waiting until then to generate the parameters is
+       * too late.  At that point, the values for the built-in uniforms won't
+       * get sent to the shader.
+       */
+      nir_foreach_variable(var, &prog->nir->uniforms) {
+         if (strncmp(var->name, "gl_", 3) == 0) {
+            const nir_state_slot *const slots = var->state_slots;
+            assert(var->state_slots != NULL);
+
+            for (unsigned int i = 0; i < var->num_state_slots; i++) {
+               _mesa_add_state_reference(prog->Parameters,
+                                         (gl_state_index *)slots[i].tokens);
+            }
+         }
+      }
    }
 
    /* The linker tries to dead code eliminate unused varying components,