glsl: parser changes for GL_ARB_explicit_uniform_location

Patch adds a preprocessor define for the extension and stores explicit
location data for uniforms during AST->HIR conversion. It also sets
layout token to be available when having the extension in place.

v2: change parser check to require GLSL 330 or enabling
    GL_ARB_explicit_attrib_location (Ian)
v3: fix the check and comment in AST->HIR (Petri)

Signed-off-by: Tapani Pälli <[email protected]>

1 files changed, 35 insertions, 0 deletions

diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index 73825760ed8..12c691a2d72 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -2181,6 +2181,41 @@ validate_explicit_location(const struct ast_type_qualifier *qual,
 {
    bool fail = false;
 
+   /* Checks for GL_ARB_explicit_uniform_location. */
+   if (qual->flags.q.uniform) {
+      if (!state->check_explicit_uniform_location_allowed(loc, var))
+         return;
+
+      const struct gl_context *const ctx = state->ctx;
+      unsigned max_loc = qual->location + var->type->uniform_locations() - 1;
+
+      /* ARB_explicit_uniform_location specification states:
+       *
+       *     "The explicitly defined locations and the generated locations
+       *     must be in the range of 0 to MAX_UNIFORM_LOCATIONS minus one."
+       *
+       *     "Valid locations for default-block uniform variable locations
+       *     are in the range of 0 to the implementation-defined maximum
+       *     number of uniform locations."
+       */
+      if (qual->location < 0) {
+         _mesa_glsl_error(loc, state,
+                          "explicit location < 0 for uniform %s", var->name);
+         return;
+      }
+
+      if (max_loc >= ctx->Const.MaxUserAssignableUniformLocations) {
+         _mesa_glsl_error(loc, state, "location(s) consumed by uniform %s "
+                          ">= MAX_UNIFORM_LOCATIONS (%u)", var->name,
+                          ctx->Const.MaxUserAssignableUniformLocations);
+         return;
+      }
+
+      var->data.explicit_location = true;
+      var->data.location = qual->location;
+      return;
+   }
+
    /* Between GL_ARB_explicit_attrib_location an
     * GL_ARB_separate_shader_objects, the inputs and outputs of any shader
     * stage can be assigned explicit locations.  The checking here associates