glsl: add support for explicit locations inside interface blocks

This change also adds explicit location support for structs and interfaces which
is currently missing in Mesa but is allowed with SSO and GLSL 1.50+.

Reviewed-by: Edward O'Callaghan <[email protected]>

4 files changed, 105 insertions, 9 deletions

diff --git a/src/glsl/ast.h b/src/glsl/ast.h
index adfc7938bff..f8ab0b71b7b 100644
--- a/src/glsl/ast.h
+++ b/src/glsl/ast.h
@@ -726,6 +726,7 @@ public:
 			  struct _mesa_glsl_parse_state *state);
 
    const char *name;
+   ast_type_qualifier *layout;
    /* List of ast_declarator_list * */
    exec_list declarations;
    bool is_declaration;
diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index 35a1e134dfa..1091c022703 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -6179,7 +6179,8 @@ ast_process_struct_or_iface_block_members(exec_list *instructions,
                                           bool allow_reserved_names,
                                           ir_variable_mode var_mode,
                                           ast_type_qualifier *layout,
-                                          unsigned block_stream)
+                                          unsigned block_stream,
+                                          unsigned expl_location)
 {
    unsigned decl_count = 0;
 
@@ -6200,6 +6201,9 @@ ast_process_struct_or_iface_block_members(exec_list *instructions,
    glsl_struct_field *const fields = ralloc_array(state, glsl_struct_field,
                                                   decl_count);
 
+   bool first_member = true;
+   bool first_member_has_explicit_location;
+
    unsigned i = 0;
    foreach_list_typed (ast_declarator_list, decl_list, link, declarations) {
       const char *type_name;
@@ -6264,6 +6268,27 @@ ast_process_struct_or_iface_block_members(exec_list *instructions,
                           "to struct or interface block members");
       }
 
+      if (is_interface) {
+         if (!first_member) {
+            if (!layout->flags.q.explicit_location &&
+                ((first_member_has_explicit_location &&
+                  !qual->flags.q.explicit_location) ||
+                 (!first_member_has_explicit_location &&
+                  qual->flags.q.explicit_location))) {
+               _mesa_glsl_error(&loc, state,
+                                "when block-level location layout qualifier "
+                                "is not supplied either all members must "
+                                "have a location layout qualifier or all "
+                                "members must not have a location layout "
+                                "qualifier");
+            }
+         } else {
+            first_member = false;
+            first_member_has_explicit_location =
+               qual->flags.q.explicit_location;
+         }
+      }
+
       if (qual->flags.q.std140 ||
           qual->flags.q.std430 ||
           qual->flags.q.packed ||
@@ -6338,7 +6363,6 @@ ast_process_struct_or_iface_block_members(exec_list *instructions,
          validate_array_dimensions(field_type, state, &loc);
          fields[i].type = field_type;
          fields[i].name = decl->identifier;
-         fields[i].location = -1;
          fields[i].interpolation =
             interpret_interpolation_qualifier(qual, var_mode, state, &loc);
          fields[i].centroid = qual->flags.q.centroid ? 1 : 0;
@@ -6346,6 +6370,22 @@ ast_process_struct_or_iface_block_members(exec_list *instructions,
          fields[i].patch = qual->flags.q.patch ? 1 : 0;
          fields[i].precision = qual->precision;
 
+         if (qual->flags.q.explicit_location) {
+            unsigned qual_location;
+            if (process_qualifier_constant(state, &loc, "location",
+                                           qual->location, &qual_location)) {
+               fields[i].location = VARYING_SLOT_VAR0 + qual_location;
+               expl_location = fields[i].location + 1;
+            }
+         } else {
+            if (layout && layout->flags.q.explicit_location) {
+               fields[i].location = expl_location;
+               expl_location = expl_location + 1;
+            } else {
+               fields[i].location = -1;
+            }
+         }
+
          /* Propogate row- / column-major information down the fields of the
           * structure or interface block.  Structures need this data because
           * the structure may contain a structure that contains ... a matrix
@@ -6444,6 +6484,16 @@ ast_struct_specifier::hir(exec_list *instructions,
 
    state->struct_specifier_depth++;
 
+   unsigned expl_location = -1;
+   if (layout && layout->flags.q.explicit_location) {
+      if (!process_qualifier_constant(state, &loc, "location",
+                                      layout->location, &expl_location)) {
+         return NULL;
+      } else {
+         expl_location = VARYING_SLOT_VAR0 + expl_location;
+      }
+   }
+
    glsl_struct_field *fields;
    unsigned decl_count =
       ast_process_struct_or_iface_block_members(instructions,
@@ -6454,8 +6504,9 @@ ast_struct_specifier::hir(exec_list *instructions,
                                                 GLSL_MATRIX_LAYOUT_INHERITED,
                                                 false /* allow_reserved_names */,
                                                 ir_var_auto,
-                                                NULL,
-                                                0 /* for interface only */);
+                                                layout,
+                                                0, /* for interface only */
+                                                expl_location);
 
    validate_identifier(this->name, loc, state);
 
@@ -6620,6 +6671,16 @@ ast_interface_block::hir(exec_list *instructions,
       return NULL;
    }
 
+   unsigned expl_location = -1;
+   if (layout.flags.q.explicit_location) {
+      if (!process_qualifier_constant(state, &loc, "location",
+                                      layout.location, &expl_location)) {
+         return NULL;
+      } else {
+         expl_location = VARYING_SLOT_VAR0 + expl_location;
+      }
+   }
+
    unsigned int num_variables =
       ast_process_struct_or_iface_block_members(&declared_variables,
                                                 state,
@@ -6630,7 +6691,8 @@ ast_interface_block::hir(exec_list *instructions,
                                                 redeclaring_per_vertex,
                                                 var_mode,
                                                 &this->layout,
-                                                qual_stream);
+                                                qual_stream,
+                                                expl_location);
 
    state->struct_specifier_depth--;
 
@@ -6969,6 +7031,10 @@ ast_interface_block::hir(exec_list *instructions,
          }
 
          var->data.stream = qual_stream;
+         if (layout.flags.q.explicit_location) {
+            var->data.location = expl_location;
+            var->data.explicit_location = true;
+         }
 
          state->symbols->add_variable(var);
          instructions->push_tail(var);
@@ -6989,6 +7055,9 @@ ast_interface_block::hir(exec_list *instructions,
          var->data.sample = fields[i].sample;
          var->data.patch = fields[i].patch;
          var->data.stream = qual_stream;
+         var->data.location = fields[i].location;
+         if (fields[i].location != -1)
+            var->data.explicit_location = true;
          var->init_interface_type(block_type);
 
          if (var_mode == ir_var_shader_in || var_mode == ir_var_uniform)
diff --git a/src/glsl/glsl_parser.yy b/src/glsl/glsl_parser.yy
index 7eb383ac60c..51796a65df9 100644
--- a/src/glsl/glsl_parser.yy
+++ b/src/glsl/glsl_parser.yy
@@ -1130,6 +1130,10 @@ fully_specified_type:
       $$->set_location_range(@1, @2);
       $$->qualifier = $1;
       $$->specifier = $2;
+      if ($$->specifier->structure != NULL &&
+          $$->specifier->structure->is_declaration) {
+            $$->specifier->structure->layout = &$$->qualifier;
+      }
    }
    ;
 
diff --git a/src/glsl/link_interface_blocks.cpp b/src/glsl/link_interface_blocks.cpp
index 61ba0785d63..64c30fea9a3 100644
--- a/src/glsl/link_interface_blocks.cpp
+++ b/src/glsl/link_interface_blocks.cpp
@@ -166,9 +166,19 @@ public:
     */
    ir_variable *lookup(ir_variable *var)
    {
-      const struct hash_entry *entry =
-         _mesa_hash_table_search(ht, var->get_interface_type()->name);
-      return entry ? (ir_variable *) entry->data : NULL;
+      if (var->data.explicit_location &&
+          var->data.location >= VARYING_SLOT_VAR0) {
+         char location_str[11];
+         snprintf(location_str, 11, "%d", var->data.location);
+
+         const struct hash_entry *entry =
+            _mesa_hash_table_search(ht, location_str);
+         return entry ? (ir_variable *) entry->data : NULL;
+      } else {
+         const struct hash_entry *entry =
+            _mesa_hash_table_search(ht, var->get_interface_type()->name);
+         return entry ? (ir_variable *) entry->data : NULL;
+      }
    }
 
    /**
@@ -176,7 +186,19 @@ public:
     */
    void store(ir_variable *var)
    {
-      _mesa_hash_table_insert(ht, var->get_interface_type()->name, var);
+      if (var->data.explicit_location &&
+          var->data.location >= VARYING_SLOT_VAR0) {
+         /* If explicit location is given then lookup the variable by location.
+          * We turn the location into a string and use this as the hash key
+          * rather than the name. Note: We allocate enough space for a 32-bit
+          * unsigned location value which is overkill but future proof.
+          */
+         char location_str[11];
+         snprintf(location_str, 11, "%d", var->data.location);
+         _mesa_hash_table_insert(ht, ralloc_strdup(mem_ctx, location_str), var);
+      } else {
+         _mesa_hash_table_insert(ht, var->get_interface_type()->name, var);
+      }
    }
 
 private: