[Mesa-dev] [PATCH v2 1/3] glsl_parser_extra: Add utility to copy symbols between symbol tables

[Neil Roberts]

From: Eduardo Lima Mitev <elima at igalia.com>

Some symbols gathered in the symbols table during parsing are needed
later for the compile and link stages, so they are moved along the
process. Currently, only functions and non-temporary variables are
copied between symbol tables. However, the built-in gl_PerVertex
interface blocks are also needed during the linking stage (the last
step), to match re-declared blocks of inter-stage shaders.

This patch adds a new utility function that will factorize current code
that copies functions and variables between two symbol tables, and in
addition will copy explicitly declared gl_PerVertex blocks too.

The function will be used in a subsequent patch.

v2 (Neil Roberts):
Allow the src symbol table to be NULL and explicitly copy the
gl_PerVertex symbols in case they are not referenced in the exec_list.

Signed-off-by: Eduardo Lima Mitev <elima at igalia.com>
Signed-off-by: Neil Roberts <nroberts at igalia.com>
---
 src/compiler/glsl/glsl_parser_extras.cpp | 43 ++++++++++++++++++++++++++++++++
 src/compiler/glsl/glsl_parser_extras.h   |  5 ++++
 2 files changed, 48 insertions(+)

diff --git a/src/compiler/glsl/glsl_parser_extras.cpp b/src/compiler/glsl/glsl_parser_extras.cpp
index 51d835b..ec4603d 100644
--- a/src/compiler/glsl/glsl_parser_extras.cpp
+++ b/src/compiler/glsl/glsl_parser_extras.cpp
@@ -1863,6 +1863,49 @@ set_shader_inout_layout(struct gl_shader *shader,
    shader->bound_image = state->bound_image_specified;
 }
 
+/* src can be NULL if only the symbols found in the exec_list should be
+ * copied
+ */
+void
+_mesa_glsl_copy_symbols_from_table(struct exec_list *shader_ir,
+                                   struct glsl_symbol_table *src,
+                                   struct glsl_symbol_table *dest)
+{
+   foreach_in_list (ir_instruction, ir, shader_ir) {
+      switch (ir->ir_type) {
+      case ir_type_function:
+         dest->add_function((ir_function *) ir);
+         break;
+      case ir_type_variable: {
+         ir_variable *const var = (ir_variable *) ir;
+
+         if (var->data.mode != ir_var_temporary)
+            dest->add_variable(var);
+         break;
+      }
+      default:
+         break;
+      }
+   }
+
+   if (src != NULL) {
+      /* Explicitly copy the gl_PerVertex interface definitions because these
+       * are needed to check they are the same during the interstage link.
+       * They can’t necessarily be found via the exec_list because the members
+       * might not be referenced. The GL spec still requires that they match
+       * in that case.
+       */
+      const glsl_type *iface =
+         src->get_interface("gl_PerVertex", ir_var_shader_in);
+      if (iface)
+         dest->add_interface(iface->name, iface, ir_var_shader_in);
+
+      iface = src->get_interface("gl_PerVertex", ir_var_shader_out);
+      if (iface)
+         dest->add_interface(iface->name, iface, ir_var_shader_out);
+   }
+}
+
 extern "C" {
 
 static void
diff --git a/src/compiler/glsl/glsl_parser_extras.h b/src/compiler/glsl/glsl_parser_extras.h
index fb35813..2e98bc7 100644
--- a/src/compiler/glsl/glsl_parser_extras.h
+++ b/src/compiler/glsl/glsl_parser_extras.h
@@ -948,6 +948,11 @@ extern int glcpp_preprocess(void *ctx, const char **shader, char **info_log,
 extern void _mesa_destroy_shader_compiler(void);
 extern void _mesa_destroy_shader_compiler_caches(void);
 
+extern void
+_mesa_glsl_copy_symbols_from_table(struct exec_list *shader_ir,
+                                   struct glsl_symbol_table *src,
+                                   struct glsl_symbol_table *dest);
+
 #ifdef __cplusplus
 }
 #endif
-- 
2.9.5