Mesa (master): st/glsl_to_nir: split the st_glsl_to_nir() function in two

[Timothy Arceri]

Module: Mesa
Branch: master
Commit: d586f39cb0fb65624d9e0534f5eaafbf2a3ccc88
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=d586f39cb0fb65624d9e0534f5eaafbf2a3ccc88

Author: Timothy Arceri <tarceri at itsqueeze.com>
Date:   Tue Nov 14 09:15:54 2017 +1100

st/glsl_to_nir: split the st_glsl_to_nir() function in two

We want to be able to generate NIR then apply NIR optimisations.
Once the optimisations are done we can then apply the new post opt
function which assigns uniforms etc based on the optimised IR.

Reviewed-by: Nicolai Hähnle <nicolai.haehnle at amd.com>

---

 src/mesa/state_tracker/st_glsl_to_nir.cpp | 56 +++++++++++++++++++------------
 1 file changed, 34 insertions(+), 22 deletions(-)

diff --git a/src/mesa/state_tracker/st_glsl_to_nir.cpp b/src/mesa/state_tracker/st_glsl_to_nir.cpp
index bb0ba07012..b51e738b8c 100644
--- a/src/mesa/state_tracker/st_glsl_to_nir.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_nir.cpp
@@ -249,7 +249,7 @@ st_nir_assign_uniform_locations(struct gl_program *prog,
 
 extern "C" {
 
-/* First half of converting glsl_to_nir.. this leaves things in a pre-
+/* First third of converting glsl_to_nir.. this leaves things in a pre-
  * nir_lower_io state, so that shader variants can more easily insert/
  * replace variables, etc.
  */
@@ -261,7 +261,6 @@ st_glsl_to_nir(struct st_context *st, struct gl_program *prog,
    struct pipe_screen *pscreen = st->pipe->screen;
    enum pipe_shader_type ptarget = pipe_shader_type_from_mesa(stage);
    const nir_shader_compiler_options *options;
-   nir_shader *nir;
 
    assert(pscreen->get_compiler_options);   /* drivers using NIR must implement this */
 
@@ -272,7 +271,17 @@ st_glsl_to_nir(struct st_context *st, struct gl_program *prog,
    if (prog->nir)
       return prog->nir;
 
-   nir = glsl_to_nir(shader_program, stage, options);
+   return glsl_to_nir(shader_program, stage, options);
+}
+
+/* Second third of converting glsl_to_nir. This creates uniforms, gathers
+ * info on varyings, etc after NIR link time opts have been applied.
+ */
+static void
+st_glsl_to_nir_post_opts(struct st_context *st, struct gl_program *prog,
+                         struct gl_shader_program *shader_program)
+{
+   nir_shader *nir = prog->nir;
 
    /* 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).
@@ -313,7 +322,7 @@ st_glsl_to_nir(struct st_context *st, struct gl_program *prog,
    NIR_PASS_V(nir, nir_lower_var_copies);
 
    /* fragment shaders may need : */
-   if (stage == MESA_SHADER_FRAGMENT) {
+   if (prog->info.stage == MESA_SHADER_FRAGMENT) {
       static const gl_state_index wposTransformState[STATE_LENGTH] = {
          STATE_INTERNAL, STATE_FB_WPOS_Y_TRANSFORM
       };
@@ -350,15 +359,11 @@ st_glsl_to_nir(struct st_context *st, struct gl_program *prog,
    if (st->ctx->_Shader->Flags & GLSL_DUMP) {
       _mesa_log("\n");
       _mesa_log("NIR IR for linked %s program %d:\n",
-             _mesa_shader_stage_to_string(stage),
+             _mesa_shader_stage_to_string(prog->info.stage),
              shader_program->Name);
       nir_print_shader(nir, _mesa_get_log_file());
       _mesa_log("\n\n");
    }
-
-   prog->nir = nir;
-
-   return nir;
 }
 
 /* TODO any better helper somewhere to sort a list? */
@@ -387,7 +392,7 @@ sort_varyings(struct exec_list *var_list)
    exec_list_move_nodes_to(&new_list, var_list);
 }
 
-/* Second half of preparing nir from glsl, which happens after shader
+/* Last third of preparing nir from glsl, which happens after shader
  * variant lowering.
  */
 void
@@ -477,7 +482,7 @@ set_st_program(struct gl_program *prog,
    }
 }
 
-struct gl_program *
+static void
 st_nir_get_mesa_program(struct gl_context *ctx,
                         struct gl_shader_program *shader_program,
                         struct gl_linked_shader *shader)
@@ -510,29 +515,36 @@ st_nir_get_mesa_program(struct gl_context *ctx,
    nir_shader *nir = st_glsl_to_nir(st, prog, shader_program, shader->Stage);
 
    set_st_program(prog, shader_program, nir);
-
-   return prog;
+   prog->nir = nir;
 }
 
 bool
 st_link_nir(struct gl_context *ctx,
             struct gl_shader_program *shader_program)
 {
+   struct st_context *st = st_context(ctx);
+
    for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
       struct gl_linked_shader *shader = shader_program->_LinkedShaders[i];
       if (shader == NULL)
          continue;
 
-      struct gl_program *linked_prog =
-         st_nir_get_mesa_program(ctx, shader_program, shader);
+      st_nir_get_mesa_program(ctx, shader_program, shader);
+   }
 
-      if (linked_prog) {
-         if (!ctx->Driver.ProgramStringNotify(ctx,
-                                              _mesa_shader_stage_to_program(i),
-                                              linked_prog)) {
-            _mesa_reference_program(ctx, &shader->Program, NULL);
-            return false;
-         }
+   for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
+      struct gl_linked_shader *shader = shader_program->_LinkedShaders[i];
+      if (shader == NULL)
+         continue;
+
+      st_glsl_to_nir_post_opts(st, shader->Program, shader_program);
+
+      assert(shader->Program);
+      if (!ctx->Driver.ProgramStringNotify(ctx,
+                                           _mesa_shader_stage_to_program(i),
+                                           shader->Program)) {
+         _mesa_reference_program(ctx, &shader->Program, NULL);
+         return false;
       }
    }