[Mesa-dev] [PATCH 4/5] glsl: update parser to allow duplicate default layout qualifiers

[Timothy Arceri]

In order to only create a single node for each default declaration
we add a new boolean parameter to the in/out merge function to
only create one once we reach the rightmost layout qualifier.

>From the ARB_shading_language_420pack spec:

   "More than one layout qualifier may appear in a single
   declaration. If the same layout-qualifier-name occurs in
   multiple layout qualifiers for the same declaration, the
   last one overrides the former ones."

Cc: Matt Turner <mattst88 at gmail.com>
---
 src/glsl/ast.h          |  4 +--
 src/glsl/ast_type.cpp   | 18 ++++++++------
 src/glsl/glsl_parser.yy | 66 ++++++++++++++++++++++++++++++++++++++++++++-----
 3 files changed, 73 insertions(+), 15 deletions(-)

diff --git a/src/glsl/ast.h b/src/glsl/ast.h
index f8ab0b7..4651669 100644
--- a/src/glsl/ast.h
+++ b/src/glsl/ast.h
@@ -704,12 +704,12 @@ struct ast_type_qualifier {
    bool merge_out_qualifier(YYLTYPE *loc,
                            _mesa_glsl_parse_state *state,
                            const ast_type_qualifier &q,
-                           ast_node* &node);
+                           ast_node* &node, bool create_node);
 
    bool merge_in_qualifier(YYLTYPE *loc,
                            _mesa_glsl_parse_state *state,
                            const ast_type_qualifier &q,
-                           ast_node* &node);
+                           ast_node* &node, bool create_node);
 
    ast_subroutine_list *subroutine_list;
 };
diff --git a/src/glsl/ast_type.cpp b/src/glsl/ast_type.cpp
index e59d1b2..32cb0a0 100644
--- a/src/glsl/ast_type.cpp
+++ b/src/glsl/ast_type.cpp
@@ -291,7 +291,7 @@ bool
 ast_type_qualifier::merge_out_qualifier(YYLTYPE *loc,
                                         _mesa_glsl_parse_state *state,
                                         const ast_type_qualifier &q,
-                                        ast_node* &node)
+                                        ast_node* &node, bool create_node)
 {
    void *mem_ctx = state;
    const bool r = this->merge_qualifier(loc, state, q);
@@ -314,7 +314,9 @@ ast_type_qualifier::merge_out_qualifier(YYLTYPE *loc,
       /* Allow future assigments of global out's stream id value */
       this->flags.q.explicit_stream = 0;
    } else if (state->stage == MESA_SHADER_TESS_CTRL) {
-      node = new(mem_ctx) ast_tcs_output_layout(*loc);
+      if (create_node) {
+         node = new(mem_ctx) ast_tcs_output_layout(*loc);
+      }
    } else {
       _mesa_glsl_error(loc, state, "out layout qualifiers only valid in "
                        "tessellation control or geometry shaders");
@@ -327,7 +329,7 @@ bool
 ast_type_qualifier::merge_in_qualifier(YYLTYPE *loc,
                                        _mesa_glsl_parse_state *state,
                                        const ast_type_qualifier &q,
-                                       ast_node* &node)
+                                       ast_node* &node, bool create_node)
 {
    void *mem_ctx = state;
    bool create_gs_ast = false;
@@ -467,10 +469,12 @@ ast_type_qualifier::merge_in_qualifier(YYLTYPE *loc,
       this->point_mode = q.point_mode;
    }
 
-   if (create_gs_ast) {
-      node = new(mem_ctx) ast_gs_input_layout(*loc, q.prim_type);
-   } else if (create_cs_ast) {
-      node = new(mem_ctx) ast_cs_input_layout(*loc, q.local_size);
+   if (create_node) {
+      if (create_gs_ast) {
+         node = new(mem_ctx) ast_gs_input_layout(*loc, q.prim_type);
+      } else if (create_cs_ast) {
+         node = new(mem_ctx) ast_cs_input_layout(*loc, q.local_size);
+      }
    }
 
    return true;
diff --git a/src/glsl/glsl_parser.yy b/src/glsl/glsl_parser.yy
index 925cb82..6099aeb 100644
--- a/src/glsl/glsl_parser.yy
+++ b/src/glsl/glsl_parser.yy
@@ -2742,7 +2742,20 @@ member_declaration:
    ;
 
 layout_uniform_defaults:
-   layout_qualifier UNIFORM ';'
+   layout_qualifier layout_uniform_defaults
+   {
+      $$ = NULL;
+      if (!state->has_420pack_or_es31()) {
+         _mesa_glsl_error(&@1, state, "duplicate layout(...) qualifiers");
+         YYERROR;
+      } else {
+         if (!state->default_uniform_qualifier->
+                merge_qualifier(& @1, state, $1)) {
+            YYERROR;
+         }
+      }
+   }
+   | layout_qualifier UNIFORM ';'
    {
       if (!state->default_uniform_qualifier->merge_qualifier(& @1, state, $1)) {
          YYERROR;
@@ -2752,7 +2765,20 @@ layout_uniform_defaults:
    ;
 
 layout_buffer_defaults:
-   layout_qualifier BUFFER ';'
+   layout_qualifier layout_buffer_defaults
+   {
+      $$ = NULL;
+      if (!state->has_420pack_or_es31()) {
+         _mesa_glsl_error(&@1, state, "duplicate layout(...) qualifiers");
+         YYERROR;
+      } else {
+         if (!state->default_shader_storage_qualifier->
+                merge_qualifier(& @1, state, $1)) {
+            YYERROR;
+         }
+      }
+   }
+   | layout_qualifier BUFFER ';'
    {
       if (!state->default_shader_storage_qualifier->merge_qualifier(& @1, state, $1)) {
          YYERROR;
@@ -2773,20 +2799,48 @@ layout_buffer_defaults:
    ;
 
 layout_in_defaults:
-   layout_qualifier IN_TOK ';'
+   layout_qualifier layout_in_defaults
    {
       $$ = NULL;
-      if (!state->in_qualifier->merge_in_qualifier(& @1, state, $1, $$)) {
+      if (!state->has_420pack_or_es31()) {
+         _mesa_glsl_error(&@1, state, "duplicate layout(...) qualifiers");
+         YYERROR;
+      } else {
+         if (!state->in_qualifier->
+                merge_in_qualifier(& @1, state, $1, $$, false)) {
+            YYERROR;
+         }
+      }
+   }
+   | layout_qualifier IN_TOK ';'
+   {
+      $$ = NULL;
+      if (!state->in_qualifier->
+             merge_in_qualifier(& @1, state, $1, $$, true)) {
          YYERROR;
       }
    }
    ;
 
 layout_out_defaults:
-   layout_qualifier OUT_TOK ';'
+   layout_qualifier layout_out_defaults
+   {
+      $$ = NULL;
+      if (!state->has_420pack_or_es31()) {
+         _mesa_glsl_error(&@1, state, "duplicate layout(...) qualifiers");
+         YYERROR;
+      } else {
+         if (!state->out_qualifier->
+                merge_out_qualifier(& @1, state, $1, $$, false)) {
+            YYERROR;
+         }
+      }
+   }
+   | layout_qualifier OUT_TOK ';'
    {
       $$ = NULL;
-      if (!state->out_qualifier->merge_out_qualifier(& @1, state, $1, $$))
+      if (!state->out_qualifier->
+             merge_out_qualifier(& @1, state, $1, $$, true))
          YYERROR;
    }
    ;
-- 
2.4.3