linker: Detect the shader that contains "main" during intrastage linking
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index 3d8f24b..11deeed 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -462,6 +462,33 @@
/**
+ * Get the function signature for main from a shader
+ */
+static ir_function_signature *
+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(&void_parameters);
+ if ((sig != NULL) && sig->is_defined) {
+ return sig;
+ }
+ }
+
+ return NULL;
+}
+
+
+/**
* Combine a group of shaders for a single stage to generate a linked shader
*
* \note
@@ -527,17 +554,30 @@
* it to the shader. Repeat until there are no undefined references or
* until a reference cannot be resolved.
*/
+ gl_shader *main = NULL;
+ for (unsigned i = 0; i < num_shaders; i++) {
+ if (get_main_function_signature(shader_list[i]) != NULL) {
+ main = shader_list[i];
+ break;
+ }
+ }
+ if (main == NULL) {
+ linker_error_printf(prog, "%s shader lacks `main'\n",
+ (shader_list[0]->Type == GL_VERTEX_SHADER)
+ ? "vertex" : "fragment");
+ return NULL;
+ }
+
+ gl_shader *const linked = _mesa_new_shader(NULL, 0, main->Type);
+ linked->ir = new(linked) exec_list;
+ clone_ir_list(linked->ir, main->ir);
+
+ populate_symbol_table(linked);
/* Resolve initializers for global variables in the linked shader.
*/
- gl_shader *const linked = _mesa_new_shader(NULL, 0, shader_list[0]->Type);
- linked->ir = new(linked) exec_list;
- clone_ir_list(linked->ir, shader_list[0]->ir);
-
- populate_symbol_table(linked);
-
return linked;
}