glsl: Properly add functions during lazy built-in prototype importing.

The original lazy built-in importing patch did not add the newly created
function to the symbol table, nor actually emit it into the IR stream.

Adding it to the symbol table is non-trivial since importing occurs when
generating some ir_call in a nested scope.  A new add_global_function
method, backed by new symbol_table code in the previous patch, handles
this.

Fixes bug #32030.

src/glsl/ast_function.cpp

@@ -99,23 +99,29 @@ match_function_by_name(exec_list *instructions, const char *name,
 {
    void *ctx = state;
    ir_function *f = state->symbols->get_function(name);
-   ir_function_signature *sig = NULL;
+   ir_function_signature *sig;
+
+   sig = f ? f->matching_signature(actual_parameters) : NULL;
 
    /* FINISHME: This doesn't handle the case where shader X contains a
     * FINISHME: matching signature but shader X + N contains an _exact_
     * FINISHME: matching signature.
     */
-   if (f != NULL) {
-      sig = f->matching_signature(actual_parameters);
-   } else if (state->symbols->get_type(name) == NULL && (state->language_version == 110 || state->symbols->get_variable(name) == NULL)) {
+   if (sig == NULL && (f == NULL || state->es_shader || !f->has_user_signature()) && state->symbols->get_type(name) == NULL && (state->language_version == 110 || state->symbols->get_variable(name) == NULL)) {
       /* The current shader doesn't contain a matching function or signature.
        * Before giving up, look for the prototype in the built-in functions.
        */
       for (unsigned i = 0; i < state->num_builtins_to_link; i++) {
-	 f = state->builtins_to_link[i]->symbols->get_function(name);
-	 sig = f ? f->matching_signature(actual_parameters) : NULL;
+	 ir_function *builtin;
+	 builtin = state->builtins_to_link[i]->symbols->get_function(name);
+	 sig = builtin ? builtin->matching_signature(actual_parameters) : NULL;
 	 if (sig != NULL) {
-	    f = new(ctx) ir_function(name);
+	    if (f == NULL) {
+	       f = new(ctx) ir_function(name);
+	       state->symbols->add_global_function(f);
+	       emit_function(state, instructions, f);
+	    }
+
 	    f->add_signature(sig->clone_prototype(f, NULL));
 	    break;
 	 }

src/glsl/glsl_symbol_table.cpp

@@ -135,6 +135,13 @@ bool glsl_symbol_table::add_function(ir_function *f)
    return _mesa_symbol_table_add_symbol(table, -1, f->name, entry) == 0;
 }
 
+void glsl_symbol_table::add_global_function(ir_function *f)
+{
+   symbol_table_entry *entry = new(mem_ctx) symbol_table_entry(f);
+   int added = _mesa_symbol_table_add_global_symbol(table, -1, f->name, entry);
+   assert(added == 0);
+}
+
 ir_variable *glsl_symbol_table::get_variable(const char *name)
 {
    symbol_table_entry *entry = get_entry(name);

src/glsl/glsl_symbol_table.h

@@ -102,6 +102,11 @@ public:
    bool add_function(ir_function *f);
    /*@}*/
 
+   /**
+    * Add an function at global scope without checking for scoping conflicts.
+    */
+   void add_global_function(ir_function *f);
+
    /**
     * \name Methods to get symbols from the table
     */