glsl: add support for unsized arrays in shader storage blocks

They only can be defined in the last position of the shader
storage blocks.

When an unsized array is used in different shaders, it might be
converted in different sized arrays, avoid get a linker error
in that case.

v2:
- Rework error condition and error messages (Timothy Arceri)

v3:
- Move OpenGL ES check to its own patch.

Signed-off-by: Samuel Iglesias Gonsalvez <[email protected]>
Reviewed-by: Jordan Justen <[email protected]>
Reviewed-by: Kristian Høgsberg <[email protected]>

5 files changed, 150 insertions, 49 deletions

diff --git a/src/glsl/ast_array_index.cpp b/src/glsl/ast_array_index.cpp
index ae399f03a9b..dfb31073f82 100644
--- a/src/glsl/ast_array_index.cpp
+++ b/src/glsl/ast_array_index.cpp
@@ -226,7 +226,8 @@ _mesa_ast_array_index_to_hir(void *mem_ctx,
              * by the linker.
              */
          }
-         else {
+         else if (array->variable_referenced()->data.mode !=
+                  ir_var_shader_storage) {
             _mesa_glsl_error(&loc, state, "unsized array index must be constant");
          }
       } else if (array->type->fields.array->is_interface()
diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index b67ae704bb0..92038a62d81 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -5880,6 +5880,19 @@ private:
    bool found;
 };
 
+static bool
+is_unsized_array_last_element(ir_variable *v)
+{
+   const glsl_type *interface_type = v->get_interface_type();
+   int length = interface_type->length;
+
+   assert(v->type->is_unsized_array());
+
+   /* Check if it is the last element of the interface */
+   if (strcmp(interface_type->fields.structure[length-1].name, v->name) == 0)
+      return true;
+   return false;
+}
 
 ir_rvalue *
 ast_interface_block::hir(exec_list *instructions,
@@ -6253,18 +6266,29 @@ ast_interface_block::hir(exec_list *instructions,
          handle_tess_ctrl_shader_output_decl(state, loc, var);
 
       for (unsigned i = 0; i < num_variables; i++) {
-         /* From GLSL ES 3.10 spec, section 4.1.9 "Arrays":
-          *
-          * "If an array is declared as the last member of a shader storage
-          * block and the size is not specified at compile-time, it is
-          * sized at run-time. In all other cases, arrays are sized only
-          * at compile-time."
-          */
-         if (state->es_shader && fields[i].type->is_unsized_array()) {
-             _mesa_glsl_error(&loc, state, "unsized array `%s' definition: "
-                              "only last member of a shader storage block "
-                              "can be defined as unsized array",
-                              fields[i].name);
+         if (fields[i].type->is_unsized_array()) {
+            if (var_mode == ir_var_shader_storage) {
+               if (i != (num_variables - 1)) {
+                  _mesa_glsl_error(&loc, state, "unsized array `%s' definition: "
+                                   "only last member of a shader storage block "
+                                   "can be defined as unsized array",
+                                   fields[i].name);
+               }
+            } else {
+               /* From GLSL ES 3.10 spec, section 4.1.9 "Arrays":
+               *
+               * "If an array is declared as the last member of a shader storage
+               * block and the size is not specified at compile-time, it is
+               * sized at run-time. In all other cases, arrays are sized only
+               * at compile-time."
+               */
+               if (state->es_shader) {
+                  _mesa_glsl_error(&loc, state, "unsized array `%s' definition: "
+                                 "only last member of a shader storage block "
+                                 "can be defined as unsized array",
+                                 fields[i].name);
+               }
+            }
          }
       }
 
@@ -6359,6 +6383,32 @@ ast_interface_block::hir(exec_list *instructions,
          var->data.explicit_binding = this->layout.flags.q.explicit_binding;
          var->data.binding = this->layout.binding;
 
+         if (var->type->is_unsized_array()) {
+            if (var->is_in_shader_storage_block()) {
+               if (!is_unsized_array_last_element(var)) {
+                  _mesa_glsl_error(&loc, state, "unsized array `%s' definition: "
+                                   "only last member of a shader storage block "
+                                   "can be defined as unsized array",
+                                   var->name);
+               }
+               var->data.from_ssbo_unsized_array = true;
+            } else {
+               /* From GLSL ES 3.10 spec, section 4.1.9 "Arrays":
+               *
+               * "If an array is declared as the last member of a shader storage
+               * block and the size is not specified at compile-time, it is
+               * sized at run-time. In all other cases, arrays are sized only
+               * at compile-time."
+               */
+               if (state->es_shader) {
+                  _mesa_glsl_error(&loc, state, "unsized array `%s' definition: "
+                                 "only last member of a shader storage block "
+                                 "can be defined as unsized array",
+                                 var->name);
+               }
+            }
+         }
+
          state->symbols->add_variable(var);
          instructions->push_tail(var);
       }
diff --git a/src/glsl/ir.cpp b/src/glsl/ir.cpp
index fb58c3b4ef6..b9df9761920 100644
--- a/src/glsl/ir.cpp
+++ b/src/glsl/ir.cpp
@@ -1658,6 +1658,7 @@ ir_variable::ir_variable(const struct glsl_type *type, const char *name,
    this->data.image_coherent = false;
    this->data.image_volatile = false;
    this->data.image_restrict = false;
+   this->data.from_ssbo_unsized_array = false;
 
    if (type != NULL) {
       if (type->base_type == GLSL_TYPE_SAMPLER)
diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index cf1954b1257..48b6795cc09 100644
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -453,6 +453,15 @@ public:
    }
 
    /**
+    * Determine whether or not a variable is part of a shader storage block.
+    */
+   inline bool is_in_shader_storage_block() const
+   {
+      return this->data.mode == ir_var_shader_storage &&
+             this->interface_type != NULL;
+   }
+
+   /**
     * Determine whether or not a variable is the declaration of an interface
     * block
     *
@@ -778,6 +787,11 @@ public:
       unsigned image_restrict:1;
 
       /**
+       * ARB_shader_storage_buffer_object
+       */
+      unsigned from_ssbo_unsized_array:1; /**< unsized array buffer variable. */
+
+      /**
        * Emit a warning if this variable is accessed.
        */
    private:
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index 53e276cc589..47d8b5ad1bf 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -877,30 +877,40 @@ validate_intrastage_arrays(struct gl_shader_program *prog,
     * In addition, set the type of the linked variable to the
     * explicitly sized array.
     */
-   if (var->type->is_array() && existing->type->is_array() &&
-       (var->type->fields.array == existing->type->fields.array) &&
-       ((var->type->length == 0)|| (existing->type->length == 0))) {
-      if (var->type->length != 0) {
-         if (var->type->length <= existing->data.max_array_access) {
-            linker_error(prog, "%s `%s' declared as type "
-                         "`%s' but outermost dimension has an index"
-                         " of `%i'\n",
-                         mode_string(var),
-                         var->name, var->type->name,
-                         existing->data.max_array_access);
-         }
-         existing->type = var->type;
-         return true;
-      } else if (existing->type->length != 0) {
-         if(existing->type->length <= var->data.max_array_access) {
-            linker_error(prog, "%s `%s' declared as type "
-                         "`%s' but outermost dimension has an index"
-                         " of `%i'\n",
-                         mode_string(var),
-                         var->name, existing->type->name,
-                         var->data.max_array_access);
+   if (var->type->is_array() && existing->type->is_array()) {
+      if ((var->type->fields.array == existing->type->fields.array) &&
+          ((var->type->length == 0)|| (existing->type->length == 0))) {
+         if (var->type->length != 0) {
+            if (var->type->length <= existing->data.max_array_access) {
+               linker_error(prog, "%s `%s' declared as type "
+                           "`%s' but outermost dimension has an index"
+                           " of `%i'\n",
+                           mode_string(var),
+                           var->name, var->type->name,
+                           existing->data.max_array_access);
+            }
+            existing->type = var->type;
+            return true;
+         } else if (existing->type->length != 0) {
+            if(existing->type->length <= var->data.max_array_access &&
+               !existing->data.from_ssbo_unsized_array) {
+               linker_error(prog, "%s `%s' declared as type "
+                           "`%s' but outermost dimension has an index"
+                           " of `%i'\n",
+                           mode_string(var),
+                           var->name, existing->type->name,
+                           var->data.max_array_access);
+            }
+            return true;
          }
-         return true;
+      } else {
+         /* The arrays of structs could have different glsl_type pointers but
+          * they are actually the same type. Use record_compare() to check that.
+          */
+         if (existing->type->fields.array->is_record() &&
+             var->type->fields.array->is_record() &&
+             existing->type->fields.array->record_compare(var->type->fields.array))
+            return true;
       }
    }
    return false;
@@ -959,12 +969,24 @@ cross_validate_globals(struct gl_shader_program *prog,
                       && existing->type->record_compare(var->type)) {
                      existing->type = var->type;
                   } else {
-                     linker_error(prog, "%s `%s' declared as type "
-                                  "`%s' and type `%s'\n",
-                                  mode_string(var),
-                                  var->name, var->type->name,
-                                  existing->type->name);
-                     return;
+                     /* If it is an unsized array in a Shader Storage Block,
+                      * two different shaders can access to different elements.
+                      * Because of that, they might be converted to different
+                      * sized arrays, then check that they are compatible but
+                      * ignore the array size.
+                      */
+                     if (!(var->data.mode == ir_var_shader_storage &&
+                           var->data.from_ssbo_unsized_array &&
+                           existing->data.mode == ir_var_shader_storage &&
+                           existing->data.from_ssbo_unsized_array &&
+                           var->type->gl_type == existing->type->gl_type)) {
+                        linker_error(prog, "%s `%s' declared as type "
+                                    "`%s' and type `%s'\n",
+                                    mode_string(var),
+                                    var->name, var->type->name,
+                                    existing->type->name);
+                        return;
+                     }
                   }
 	       }
 	    }
@@ -1364,12 +1386,14 @@ public:
 
    virtual ir_visitor_status visit(ir_variable *var)
    {
-      fixup_type(&var->type, var->data.max_array_access);
+      fixup_type(&var->type, var->data.max_array_access,
+                 var->data.from_ssbo_unsized_array);
       if (var->type->is_interface()) {
          if (interface_contains_unsized_arrays(var->type)) {
             const glsl_type *new_type =
                resize_interface_members(var->type,
-                                        var->get_max_ifc_array_access());
+                                        var->get_max_ifc_array_access(),
+                                        var->is_in_shader_storage_block());
             var->type = new_type;
             var->change_interface_type(new_type);
          }
@@ -1378,7 +1402,8 @@ public:
          if (interface_contains_unsized_arrays(var->type->fields.array)) {
             const glsl_type *new_type =
                resize_interface_members(var->type->fields.array,
-                                        var->get_max_ifc_array_access());
+                                        var->get_max_ifc_array_access(),
+                                        var->is_in_shader_storage_block());
             var->change_interface_type(new_type);
             var->type = update_interface_members_array(var->type, new_type);
          }
@@ -1419,9 +1444,10 @@ private:
     * If the type pointed to by \c type represents an unsized array, replace
     * it with a sized array whose size is determined by max_array_access.
     */
-   static void fixup_type(const glsl_type **type, unsigned max_array_access)
+   static void fixup_type(const glsl_type **type, unsigned max_array_access,
+                          bool from_ssbo_unsized_array)
    {
-      if ((*type)->is_unsized_array()) {
+      if (!from_ssbo_unsized_array && (*type)->is_unsized_array()) {
          *type = glsl_type::get_array_instance((*type)->fields.array,
                                                max_array_access + 1);
          assert(*type != NULL);
@@ -1464,14 +1490,23 @@ private:
     */
    static const glsl_type *
    resize_interface_members(const glsl_type *type,
-                            const unsigned *max_ifc_array_access)
+                            const unsigned *max_ifc_array_access,
+                            bool is_ssbo)
    {
       unsigned num_fields = type->length;
       glsl_struct_field *fields = new glsl_struct_field[num_fields];
       memcpy(fields, type->fields.structure,
              num_fields * sizeof(*fields));
       for (unsigned i = 0; i < num_fields; i++) {
-         fixup_type(&fields[i].type, max_ifc_array_access[i]);
+         /* If SSBO last member is unsized array, we don't replace it by a sized
+          * array.
+          */
+         if (is_ssbo && i == (num_fields - 1))
+            fixup_type(&fields[i].type, max_ifc_array_access[i],
+                       true);
+         else
+            fixup_type(&fields[i].type, max_ifc_array_access[i],
+                       false);
       }
       glsl_interface_packing packing =
          (glsl_interface_packing) type->interface_packing;