glsl: Move link_get_main_function_signature to a common location

Also rename to _mesa_get_main_function_signature.

We will call it near the end of compilation to insert some code into
main for initializing some compute shader global variables.

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Eduardo Lima Mitev <elima@igalia.com>

src/glsl/builtin_functions.cpp

@@ -5121,4 +5121,32 @@ _mesa_glsl_get_builtin_function_shader()
    return builtins.shader;
 }
 
+
+/**
+ * Get the function signature for main from a shader
+ */
+ir_function_signature *
+_mesa_get_main_function_signature(gl_shader *sh)
+{
+   ir_function *const f = sh->symbols->get_function("main");
+   if (f != NULL) {
+      exec_list void_parameters;
+
+      /* Look for the 'void main()' signature and ensure that it's defined.
+       * This keeps the linker from accidentally pick a shader that just
+       * contains a prototype for main.
+       *
+       * We don't have to check for multiple definitions of main (in multiple
+       * shaders) because that would have already been caught above.
+       */
+      ir_function_signature *sig =
+         f->matching_signature(NULL, &void_parameters, false);
+      if ((sig != NULL) && sig->is_defined) {
+         return sig;
+      }
+   }
+
+   return NULL;
+}
+
 /** @} */

src/glsl/ir.h

@@ -2529,6 +2529,9 @@ _mesa_glsl_find_builtin_function_by_name(const char *name);
 extern gl_shader *
 _mesa_glsl_get_builtin_function_shader(void);
 
+extern ir_function_signature *
+_mesa_get_main_function_signature(gl_shader *sh);
+
 extern void
 _mesa_glsl_release_functions(void);
 

src/glsl/linker.cpp

@@ -1341,33 +1341,6 @@ move_non_declarations(exec_list *instructions, exec_node *last,
    return last;
 }
 
-/**
- * Get the function signature for main from a shader
- */
-ir_function_signature *
-link_get_main_function_signature(gl_shader *sh)
-{
-   ir_function *const f = sh->symbols->get_function("main");
-   if (f != NULL) {
-      exec_list void_parameters;
-
-      /* Look for the 'void main()' signature and ensure that it's defined.
-       * This keeps the linker from accidentally pick a shader that just
-       * contains a prototype for main.
-       *
-       * We don't have to check for multiple definitions of main (in multiple
-       * shaders) because that would have already been caught above.
-       */
-      ir_function_signature *sig =
-         f->matching_signature(NULL, &void_parameters, false);
-      if ((sig != NULL) && sig->is_defined) {
-	 return sig;
-      }
-   }
-
-   return NULL;
-}
-
 
 /**
  * This class is only used in link_intrastage_shaders() below but declaring
@@ -2040,7 +2013,7 @@ link_intrastage_shaders(void *mem_ctx,
     */
    gl_shader *main = NULL;
    for (unsigned i = 0; i < num_shaders; i++) {
-      if (link_get_main_function_signature(shader_list[i]) != NULL) {
+      if (_mesa_get_main_function_signature(shader_list[i]) != NULL) {
 	 main = shader_list[i];
 	 break;
       }
@@ -2072,7 +2045,7 @@ link_intrastage_shaders(void *mem_ctx,
     * copy of the original shader that contained the main function).
     */
    ir_function_signature *const main_sig =
-      link_get_main_function_signature(linked);
+      _mesa_get_main_function_signature(linked);
 
    /* Move any instructions other than variable declarations or function
     * declarations into main.

src/glsl/linker.h

@@ -26,9 +26,6 @@
 #ifndef GLSL_LINKER_H
 #define GLSL_LINKER_H
 
-ir_function_signature *
-link_get_main_function_signature(gl_shader *sh);
-
 extern bool
 link_function_calls(gl_shader_program *prog, gl_shader *main,
 		    gl_shader **shader_list, unsigned num_shaders);

src/glsl/lower_vertex_id.cpp

@@ -130,7 +130,7 @@ lower_vertex_id(gl_shader *shader)
       return false;
 
    ir_function_signature *const main_sig =
-      link_get_main_function_signature(shader);
+      _mesa_get_main_function_signature(shader);
    if (main_sig == NULL) {
       assert(main_sig != NULL);
       return false;