[Mesa-dev] [PATCH 05/30] glsl/linker: Refactor in preparation for adding more shader stages.

[Paul Berry]

Rather than maintain separately named arrays and counts for vertex,
geometry, and fragment shaders, just maintain these as arrays indexed
by the gl_shader_type enum.
---
 src/glsl/linker.cpp | 114 ++++++++++++++++++----------------------------------
 1 file changed, 39 insertions(+), 75 deletions(-)

diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index e820f0f..f3fd66f 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -1994,19 +1994,14 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
 
    /* Separate the shaders into groups based on their type.
     */
-   struct gl_shader **vert_shader_list;
-   unsigned num_vert_shaders = 0;
-   struct gl_shader **frag_shader_list;
-   unsigned num_frag_shaders = 0;
-   struct gl_shader **geom_shader_list;
-   unsigned num_geom_shaders = 0;
-
-   vert_shader_list = (struct gl_shader **)
-      calloc(prog->NumShaders, sizeof(struct gl_shader *));
-   frag_shader_list = (struct gl_shader **)
-      calloc(prog->NumShaders, sizeof(struct gl_shader *));
-   geom_shader_list = (struct gl_shader **)
-      calloc(prog->NumShaders, sizeof(struct gl_shader *));
+   struct gl_shader **shader_list[MESA_SHADER_STAGES];
+   unsigned num_shaders[MESA_SHADER_STAGES];
+
+   for (int i = 0; i < MESA_SHADER_STAGES; i++) {
+      shader_list[i] = (struct gl_shader **)
+         calloc(prog->NumShaders, sizeof(struct gl_shader *));
+      num_shaders[i] = 0;
+   }
 
    unsigned min_version = UINT_MAX;
    unsigned max_version = 0;
@@ -2022,20 +2017,9 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
 	 goto done;
       }
 
-      switch (prog->Shaders[i]->Stage) {
-      case MESA_SHADER_VERTEX:
-	 vert_shader_list[num_vert_shaders] = prog->Shaders[i];
-	 num_vert_shaders++;
-	 break;
-      case MESA_SHADER_FRAGMENT:
-	 frag_shader_list[num_frag_shaders] = prog->Shaders[i];
-	 num_frag_shaders++;
-	 break;
-      case MESA_SHADER_GEOMETRY:
-	 geom_shader_list[num_geom_shaders] = prog->Shaders[i];
-	 num_geom_shaders++;
-	 break;
-      }
+      gl_shader_stage shader_type = prog->Shaders[i]->Stage;
+      shader_list[shader_type][num_shaders[shader_type]] = prog->Shaders[i];
+      num_shaders[shader_type]++;
    }
 
    /* In desktop GLSL, different shader versions may be linked together.  In
@@ -2052,7 +2036,8 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
 
    /* Geometry shaders have to be linked with vertex shaders.
     */
-   if (num_geom_shaders > 0 && num_vert_shaders == 0) {
+   if (num_shaders[MESA_SHADER_GEOMETRY] > 0 &&
+       num_shaders[MESA_SHADER_VERTEX] == 0) {
       linker_error(prog, "Geometry shader must be linked with "
 		   "vertex shader\n");
       goto done;
@@ -2067,55 +2052,37 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
 
    /* Link all shaders for a particular stage and validate the result.
     */
-   if (num_vert_shaders > 0) {
-      gl_shader *const sh =
-	 link_intrastage_shaders(mem_ctx, ctx, prog, vert_shader_list,
-				 num_vert_shaders);
-
-      if (!prog->LinkStatus)
-	 goto done;
-
-      validate_vertex_shader_executable(prog, sh);
-      if (!prog->LinkStatus)
-	 goto done;
-      prog->LastClipDistanceArraySize = prog->Vert.ClipDistanceArraySize;
+   for (int stage = 0; stage < MESA_SHADER_STAGES; stage++) {
+      if (num_shaders[stage] > 0) {
+         gl_shader *const sh =
+            link_intrastage_shaders(mem_ctx, ctx, prog, shader_list[stage],
+                                    num_shaders[stage]);
 
-      _mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_VERTEX],
-			     sh);
-   }
-
-   if (num_frag_shaders > 0) {
-      gl_shader *const sh =
-	 link_intrastage_shaders(mem_ctx, ctx, prog, frag_shader_list,
-				 num_frag_shaders);
-
-      if (!prog->LinkStatus)
-	 goto done;
+         if (!prog->LinkStatus)
+            goto done;
 
-      validate_fragment_shader_executable(prog, sh);
-      if (!prog->LinkStatus)
-	 goto done;
+         switch (stage) {
+         case MESA_SHADER_VERTEX:
+            validate_vertex_shader_executable(prog, sh);
+            break;
+         case MESA_SHADER_GEOMETRY:
+            validate_geometry_shader_executable(prog, sh);
+            break;
+         case MESA_SHADER_FRAGMENT:
+            validate_fragment_shader_executable(prog, sh);
+            break;
+         }
+         if (!prog->LinkStatus)
+            goto done;
 
-      _mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_FRAGMENT],
-			     sh);
+         _mesa_reference_shader(ctx, &prog->_LinkedShaders[stage], sh);
+      }
    }
 
-   if (num_geom_shaders > 0) {
-      gl_shader *const sh =
-	 link_intrastage_shaders(mem_ctx, ctx, prog, geom_shader_list,
-				 num_geom_shaders);
-
-      if (!prog->LinkStatus)
-	 goto done;
-
-      validate_geometry_shader_executable(prog, sh);
-      if (!prog->LinkStatus)
-	 goto done;
+   if (num_shaders[MESA_SHADER_GEOMETRY] > 0)
       prog->LastClipDistanceArraySize = prog->Geom.ClipDistanceArraySize;
-
-      _mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_GEOMETRY],
-			     sh);
-   }
+   else
+      prog->LastClipDistanceArraySize = prog->Vert.ClipDistanceArraySize;
 
    /* Here begins the inter-stage linking phase.  Some initial validation is
     * performed, then locations are assigned for uniforms, attributes, and
@@ -2373,11 +2340,8 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
    /* FINISHME: Assign fragment shader output locations. */
 
 done:
-   free(vert_shader_list);
-   free(frag_shader_list);
-   free(geom_shader_list);
-
    for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
+      free(shader_list[i]);
       if (prog->_LinkedShaders[i] == NULL)
 	 continue;
 
-- 
1.8.5.2