Mesa (master): glsl: Count shader inputs and outputs separately

[Ian Romanick]

Module: Mesa
Branch: master
Commit: 42305fb50256c12b8e7a516115e72ae7089ccd1b
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=42305fb50256c12b8e7a516115e72ae7089ccd1b

Author: Ian Romanick <ian.d.romanick at intel.com>
Date:   Tue Sep 10 12:00:34 2013 -0500

glsl: Count shader inputs and outputs separately

Starting with OpenGL 3.2 input limits and output limits for stages may
not match.  This means they need to be accounted separately.

No piglit regressions.

Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
Reviewed-by: Brian Paul <brianp at vmware.com>
Reviewed-by: Marek Olšák <marek.olsak at amd.com>
Reviewed-by: Paul Berry <stereotype441 at gmail.com>

---

 src/glsl/link_varyings.cpp |  101 ++++++++++++++++++++++++++++++++++---------
 src/glsl/link_varyings.h   |   11 ++++-
 src/glsl/linker.cpp        |    4 +-
 3 files changed, 91 insertions(+), 25 deletions(-)

diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
index 905621d..9d633e8 100644
--- a/src/glsl/link_varyings.cpp
+++ b/src/glsl/link_varyings.cpp
@@ -1220,39 +1220,98 @@ assign_varying_locations(struct gl_context *ctx,
 }
 
 bool
-check_against_varying_limit(struct gl_context *ctx,
-                            struct gl_shader_program *prog,
-                            gl_shader *consumer)
+check_against_output_limit(struct gl_context *ctx,
+                           struct gl_shader_program *prog,
+                           gl_shader *producer)
 {
-   unsigned varying_vectors = 0;
+   unsigned output_vectors = 0;
+
+   foreach_list(node, producer->ir) {
+      ir_variable *const var = ((ir_instruction *) node)->as_variable();
+
+      if (var && var->mode == ir_var_shader_out &&
+          is_varying_var(producer->Type, var)) {
+         output_vectors += var->type->count_attribute_slots();
+      }
+   }
+
+   unsigned max_output_components;
+   switch (producer->Type) {
+   case GL_VERTEX_SHADER:
+      max_output_components = ctx->Const.VertexProgram.MaxOutputComponents;
+      break;
+   case GL_GEOMETRY_SHADER:
+      max_output_components = ctx->Const.GeometryProgram.MaxOutputComponents;
+      break;
+   case GL_FRAGMENT_SHADER:
+   default:
+      assert(!"Should not get here.");
+      return false;
+   }
+
+   const unsigned output_components = output_vectors * 4;
+   if (output_components > max_output_components) {
+      if (ctx->API == API_OPENGLES2 || prog->IsES)
+         linker_error(prog, "shader uses too many output vectors "
+                      "(%u > %u)\n",
+                      output_vectors,
+                      max_output_components / 4);
+      else
+         linker_error(prog, "shader uses too many output components "
+                      "(%u > %u)\n",
+                      output_components,
+                      max_output_components);
+
+      return false;
+   }
+
+   return true;
+}
+
+bool
+check_against_input_limit(struct gl_context *ctx,
+                          struct gl_shader_program *prog,
+                          gl_shader *consumer)
+{
+   unsigned input_vectors = 0;
 
    foreach_list(node, consumer->ir) {
       ir_variable *const var = ((ir_instruction *) node)->as_variable();
 
       if (var && var->mode == ir_var_shader_in &&
           is_varying_var(consumer->Type, var)) {
-         /* The packing rules used for vertex shader inputs are also
-          * used for fragment shader inputs.
-          */
-         varying_vectors += var->type->count_attribute_slots();
+         input_vectors += var->type->count_attribute_slots();
       }
    }
 
-   if (ctx->API == API_OPENGLES2 || prog->IsES) {
-      if (varying_vectors > ctx->Const.MaxVarying) {
-         linker_error(prog, "shader uses too many varying vectors "
+   unsigned max_input_components;
+   switch (consumer->Type) {
+   case GL_GEOMETRY_SHADER:
+      max_input_components = ctx->Const.GeometryProgram.MaxInputComponents;
+      break;
+   case GL_FRAGMENT_SHADER:
+      max_input_components = ctx->Const.FragmentProgram.MaxInputComponents;
+      break;
+   case GL_VERTEX_SHADER:
+   default:
+      assert(!"Should not get here.");
+      return false;
+   }
+
+   const unsigned input_components = input_vectors * 4;
+   if (input_components > max_input_components) {
+      if (ctx->API == API_OPENGLES2 || prog->IsES)
+         linker_error(prog, "shader uses too many input vectors "
                       "(%u > %u)\n",
-                      varying_vectors, ctx->Const.MaxVarying);
-         return false;
-      }
-   } else {
-      const unsigned float_components = varying_vectors * 4;
-      if (float_components > ctx->Const.MaxVarying * 4) {
-         linker_error(prog, "shader uses too many varying components "
+                      input_vectors,
+                      max_input_components / 4);
+      else
+         linker_error(prog, "shader uses too many input components "
                       "(%u > %u)\n",
-                      float_components, ctx->Const.MaxVarying * 4);
-         return false;
-      }
+                      input_components,
+                      max_input_components);
+
+      return false;
    }
 
    return true;
diff --git a/src/glsl/link_varyings.h b/src/glsl/link_varyings.h
index 6264ef0..6fa2681 100644
--- a/src/glsl/link_varyings.h
+++ b/src/glsl/link_varyings.h
@@ -237,8 +237,13 @@ assign_varying_locations(struct gl_context *ctx,
                          unsigned gs_input_vertices);
 
 bool
-check_against_varying_limit(struct gl_context *ctx,
-                            struct gl_shader_program *prog,
-                            gl_shader *consumer);
+check_against_output_limit(struct gl_context *ctx,
+                           struct gl_shader_program *prog,
+                           gl_shader *producer);
+
+bool
+check_against_input_limit(struct gl_context *ctx,
+                          struct gl_shader_program *prog,
+                          gl_shader *consumer);
 
 #endif /* GLSL_LINK_VARYINGS_H */
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index c54b704..61904dc 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -2203,7 +2203,9 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
          ;
 
       /* This must be done after all dead varyings are eliminated. */
-      if (!check_against_varying_limit(ctx, prog, sh_next))
+      if (!check_against_output_limit(ctx, prog, sh_i))
+         goto done;
+      if (!check_against_input_limit(ctx, prog, sh_next))
          goto done;
 
       next = i;