glsl_parser_extra: Add utility to copy symbols between symbol tables

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.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Eduardo Lima Mitev <elima@igalia.com>
Signed-off-by: Neil Roberts <nroberts@igalia.com>
(cherry picked from commit 4c62a270a99d443316e29020377465a90a6968c0)

2 files changed, 48 insertions, 0 deletions

diff --git a/src/compiler/glsl/glsl_parser_extras.cpp b/src/compiler/glsl/glsl_parser_extras.cpp
index 6753f649009..1d546304f8f 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 be6c8dce6b4..820d4423d58 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