glsl: Prohibit illegal mixing of redeclarations inside/outside gl_PerVertex.

From section 7.1 (Built-In Language Variables) of the GLSL 4.10
spec:

    Also, if a built-in interface block is redeclared, no member of
    the built-in declaration can be redeclared outside the block
    redeclaration.

We have been regarding this text as a clarification to the behaviour
established for gl_PerVertex by GLSL 1.50, so we apply it regardless
of GLSL version.

This patch enforces the rule by adding an enum to ir_variable to track
how the variable was declared: implicitly, normally, or in an
interface block.

Fixes piglit tests:
- gs-redeclares-pervertex-out-after-global-redeclaration.geom
- vs-redeclares-pervertex-out-after-global-redeclaration.vert
- gs-redeclares-pervertex-out-after-other-global-redeclaration.geom
- vs-redeclares-pervertex-out-after-other-global-redeclaration.vert
- gs-redeclares-pervertex-out-before-global-redeclaration
- vs-redeclares-pervertex-out-before-global-redeclaration

Cc: "10.0" <mesa-stable@lists.freedesktop.org>

v2: Don't set "how_declared" redundantly in builtin_variables.cpp.
Properly clone "how_declared".

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
(cherry picked from commit 2bbcf19acad530d339ffe8e007fe2f6a244e1580)

1 files changed, 20 insertions, 0 deletions

diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index 76b256c731a..01280478c95 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -3355,6 +3355,15 @@ ast_declarator_list::hir(exec_list *instructions,
       ir_variable *earlier =
          get_variable_being_redeclared(var, decl->get_location(), state,
                                        false /* allow_all_redeclarations */);
+      if (earlier != NULL) {
+         if (strncmp(var->name, "gl_", 3) == 0 &&
+             earlier->how_declared == ir_var_declared_in_block) {
+            _mesa_glsl_error(&loc, state,
+                             "`%s' has already been redeclared using "
+                             "gl_PerVertex", var->name);
+         }
+         earlier->how_declared = ir_var_declared_normally;
+      }
 
       if (decl->initializer != NULL) {
 	 result = process_initializer((earlier == NULL) ? var : earlier,
@@ -5048,6 +5057,7 @@ ast_interface_block::hir(exec_list *instructions,
             _mesa_glsl_error(&loc, state, "`%s' redeclared",
                              this->instance_name);
          }
+         earlier->how_declared = ir_var_declared_normally;
          earlier->type = var->type;
          earlier->reinit_interface_type(block_type);
          delete var;
@@ -5078,7 +5088,11 @@ ast_interface_block::hir(exec_list *instructions,
                _mesa_glsl_error(&loc, state,
                                 "redeclaration of gl_PerVertex can only "
                                 "include built-in variables");
+            } else if (earlier->how_declared == ir_var_declared_normally) {
+               _mesa_glsl_error(&loc, state,
+                                "`%s' has already been redeclared", var->name);
             } else {
+               earlier->how_declared = ir_var_declared_in_block;
                earlier->reinit_interface_type(block_type);
             }
             continue;
@@ -5125,6 +5139,12 @@ ast_interface_block::hir(exec_list *instructions,
             if (var != NULL &&
                 var->get_interface_type() == earlier_per_vertex &&
                 var->mode == var_mode) {
+               if (var->how_declared == ir_var_declared_normally) {
+                  _mesa_glsl_error(&loc, state,
+                                   "redeclaration of gl_PerVertex cannot "
+                                   "follow a redeclaration of `%s'",
+                                   var->name);
+               }
                state->symbols->disable_variable(var->name);
                var->remove();
             }