glsl: use an enum for AMD_conservative_depth layout qualifiers

The main idea behind this is to free some bits in the flags.q
struct because currently all 64-bits are used and we can't
add more layout qualifiers without reaching a static assert.

In order to do that (mainly for ARB_bindless_texture), use an
enumeration for the AMD_conservative_depth layout qualifiers
because it's forbidden to declare more than one depth qualifier
for gl_FragDepth.

Note that ast_type_qualifier::merge_qualifier() will prevent
using duplicate layout qualifiers by returning a compile-time
error.

No piglit regressions found (including compiler tests) with
RX480 on RadeonSI.

v2: use a switch case

Signed-off-by: Samuel Pitoiset <[email protected]>
Reviewed-by: Andres Gomez <[email protected]> (v1)

4 files changed, 40 insertions, 35 deletions

diff --git a/src/compiler/glsl/ast.h b/src/compiler/glsl/ast.h
index 3dff164232d..11a092e41c2 100644
--- a/src/compiler/glsl/ast.h
+++ b/src/compiler/glsl/ast.h
@@ -463,6 +463,14 @@ enum {
    ast_precision_low
 };
 
+enum {
+   ast_depth_none = 0, /**< Absence of depth qualifier. */
+   ast_depth_any,
+   ast_depth_greater,
+   ast_depth_less,
+   ast_depth_unchanged
+};
+
 struct ast_type_qualifier {
    DECLARE_RALLOC_CXX_OPERATORS(ast_type_qualifier);
 
@@ -528,10 +536,7 @@ struct ast_type_qualifier {
 
          /** \name Layout qualifiers for GL_AMD_conservative_depth */
          /** \{ */
-         unsigned depth_any:1;
-         unsigned depth_greater:1;
-         unsigned depth_less:1;
-         unsigned depth_unchanged:1;
+         unsigned depth_type:1;
          /** \} */
 
 	 /** \name Layout qualifiers for GL_ARB_uniform_buffer_object */
@@ -630,6 +635,9 @@ struct ast_type_qualifier {
    /** Precision of the type (highp/medium/lowp). */
    unsigned precision:2;
 
+   /** Type of layout qualifiers for GL_AMD_conservative_depth. */
+   unsigned depth_type:3;
+
    /**
     * Alignment specified via GL_ARB_enhanced_layouts "align" layout qualifier
     */
diff --git a/src/compiler/glsl/ast_to_hir.cpp b/src/compiler/glsl/ast_to_hir.cpp
index db48cf81134..8424b5bb3f2 100644
--- a/src/compiler/glsl/ast_to_hir.cpp
+++ b/src/compiler/glsl/ast_to_hir.cpp
@@ -3629,11 +3629,7 @@ apply_layout_qualifier_to_variable(const struct ast_type_qualifier *qual,
    /* Layout qualifiers for gl_FragDepth, which are enabled by extension
     * AMD_conservative_depth.
     */
-   int depth_layout_count = qual->flags.q.depth_any
-      + qual->flags.q.depth_greater
-      + qual->flags.q.depth_less
-      + qual->flags.q.depth_unchanged;
-   if (depth_layout_count > 0
+   if (qual->flags.q.depth_type
        && !state->is_version(420, 0)
        && !state->AMD_conservative_depth_enable
        && !state->ARB_conservative_depth_enable) {
@@ -3641,27 +3637,30 @@ apply_layout_qualifier_to_variable(const struct ast_type_qualifier *qual,
                         "extension GL_AMD_conservative_depth or "
                         "GL_ARB_conservative_depth must be enabled "
                         "to use depth layout qualifiers");
-   } else if (depth_layout_count > 0
+   } else if (qual->flags.q.depth_type
               && strcmp(var->name, "gl_FragDepth") != 0) {
        _mesa_glsl_error(loc, state,
                         "depth layout qualifiers can be applied only to "
                         "gl_FragDepth");
-   } else if (depth_layout_count > 1
-              && strcmp(var->name, "gl_FragDepth") == 0) {
-      _mesa_glsl_error(loc, state,
-                       "at most one depth layout qualifier can be applied to "
-                       "gl_FragDepth");
    }
-   if (qual->flags.q.depth_any)
+
+   switch (qual->depth_type) {
+   case ast_depth_any:
       var->data.depth_layout = ir_depth_layout_any;
-   else if (qual->flags.q.depth_greater)
+      break;
+   case ast_depth_greater:
       var->data.depth_layout = ir_depth_layout_greater;
-   else if (qual->flags.q.depth_less)
+      break;
+   case ast_depth_less:
       var->data.depth_layout = ir_depth_layout_less;
-   else if (qual->flags.q.depth_unchanged)
-       var->data.depth_layout = ir_depth_layout_unchanged;
-   else
-       var->data.depth_layout = ir_depth_layout_none;
+      break;
+   case ast_depth_unchanged:
+      var->data.depth_layout = ir_depth_layout_unchanged;
+      break;
+   default:
+      var->data.depth_layout = ir_depth_layout_none;
+      break;
+   }
 
    if (qual->flags.q.std140 ||
        qual->flags.q.std430 ||
diff --git a/src/compiler/glsl/ast_type.cpp b/src/compiler/glsl/ast_type.cpp
index e3f06a9900d..580d216b303 100644
--- a/src/compiler/glsl/ast_type.cpp
+++ b/src/compiler/glsl/ast_type.cpp
@@ -63,10 +63,7 @@ ast_type_qualifier::has_layout() const
 {
    return this->flags.q.origin_upper_left
           || this->flags.q.pixel_center_integer
-          || this->flags.q.depth_any
-          || this->flags.q.depth_greater
-          || this->flags.q.depth_less
-          || this->flags.q.depth_unchanged
+          || this->flags.q.depth_type
           || this->flags.q.std140
           || this->flags.q.std430
           || this->flags.q.shared
@@ -718,7 +715,7 @@ ast_type_qualifier::validate_flags(YYLTYPE *loc,
                     "%s '%s':"
                     "%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s"
                     "%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s"
-                    "%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
+                    "%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
                     message, name,
                     bad.flags.q.invariant ? " invariant" : "",
                     bad.flags.q.precise ? " precise" : "",
@@ -744,10 +741,7 @@ ast_type_qualifier::validate_flags(YYLTYPE *loc,
                     bad.flags.q.explicit_index ? " index" : "",
                     bad.flags.q.explicit_binding ? " binding" : "",
                     bad.flags.q.explicit_offset ? " offset" : "",
-                    bad.flags.q.depth_any ? " depth_any" : "",
-                    bad.flags.q.depth_greater ? " depth_greater" : "",
-                    bad.flags.q.depth_less ? " depth_less" : "",
-                    bad.flags.q.depth_unchanged ? " depth_unchanged" : "",
+                    bad.flags.q.depth_type ? " depth_type" : "",
                     bad.flags.q.std140 ? " std140" : "",
                     bad.flags.q.std430 ? " std430" : "",
                     bad.flags.q.shared ? " shared" : "",
diff --git a/src/compiler/glsl/glsl_parser.yy b/src/compiler/glsl/glsl_parser.yy
index 146c9628973..7777d703f8c 100644
--- a/src/compiler/glsl/glsl_parser.yy
+++ b/src/compiler/glsl/glsl_parser.yy
@@ -1227,14 +1227,18 @@ layout_qualifier_id:
            state->ARB_conservative_depth_enable ||
            state->is_version(420, 0))) {
          if (match_layout_qualifier($1, "depth_any", state) == 0) {
-            $$.flags.q.depth_any = 1;
+            $$.flags.q.depth_type = 1;
+            $$.depth_type = ast_depth_any;
          } else if (match_layout_qualifier($1, "depth_greater", state) == 0) {
-            $$.flags.q.depth_greater = 1;
+            $$.flags.q.depth_type = 1;
+            $$.depth_type = ast_depth_greater;
          } else if (match_layout_qualifier($1, "depth_less", state) == 0) {
-            $$.flags.q.depth_less = 1;
+            $$.flags.q.depth_type = 1;
+            $$.depth_type = ast_depth_less;
          } else if (match_layout_qualifier($1, "depth_unchanged",
                                            state) == 0) {
-            $$.flags.q.depth_unchanged = 1;
+            $$.flags.q.depth_type = 1;
+            $$.depth_type = ast_depth_unchanged;
          }
 
          if ($$.flags.i && state->AMD_conservative_depth_warn) {