Introduce IR_LINKAGE_NO_CODEGEN

This is used to implement C99 "inline"/GNU89 "extern inline" ie. an
entity which is externally defined but where we know an inlineable
definition anyway.

include/libfirm/typerep.h

@@ -154,7 +154,15 @@ typedef enum ir_linkage {
 	 * read/write behaviour to global variables or changing calling conventions
 	 * from cdecl to fastcall.
 	 */
-	IR_LINKAGE_HIDDEN_USER     = 1 << 4
+	IR_LINKAGE_HIDDEN_USER     = 1 << 4,
+	/**
+	 * Do not generate code even if the entity has a graph attached. The graph
+	 * is only used for inlining. Otherwise the entity is regarded as a
+	 * declaration of an externally defined entity.
+	 * This linkage flag can be used to implement C99 "inline" or GNU89
+	 * "extern inline".
+	 */
+	IR_LINKAGE_NO_CODEGEN      = 1 << 5,
 } ir_linkage;
 ENUM_BITSET(ir_linkage)
 
@@ -180,7 +188,8 @@ FIRM_API int entity_is_externally_visible(const ir_entity *entity);
 
 /**
  * Returns 1 if the entity has a definition (initializer) in the current
- * compilation unit
+ * compilation unit. Note that this function returns false if
+ * IR_LINKAGE_NO_CODEGEN is set even if a graph is present.
  */
 FIRM_API int entity_has_definition(const ir_entity *entity);
 

ir/be/begnuas.c

@@ -1587,14 +1587,10 @@ static void emit_global(be_gas_decl_env_t *env, const ir_entity *entity)
 	if (type == get_code_type())
 		return;
 
-	/* we already emitted all methods. Except for the trampolines which
-	 * the assembler/linker generates */
+	/* we already emitted all methods with graphs in other functions like
+	 * be_gas_emit_function_prolog(). All others don't need to be emitted.
+	 */
 	if (is_Method_type(type) && section != GAS_SECTION_PIC_TRAMPOLINES) {
-		/* functions with graph are already emitted with
-		 * be_gas_emit_function_prolog */
-		if (get_entity_irg(entity) == NULL) {
-			emit_visibility(entity);
-		}
 		return;
 	}
 

ir/be/bemain.c

@@ -520,7 +520,9 @@ static void be_main_loop(FILE *file_handle, const char *cup_name)
 {
 	static const char suffix[] = ".prof";
 
-	size_t        i, num_birgs;
+	size_t        i;
+	size_t        num_irgs;
+	size_t        num_birgs;
 	be_main_env_t env;
 	char          prof_filename[256];
 	be_irg_t      *birgs;
@@ -543,15 +545,19 @@ static void be_main_loop(FILE *file_handle, const char *cup_name)
 	arch_env = env.arch_env;
 
 	/* we might need 1 birg more for instrumentation constructor */
-	num_birgs = get_irp_n_irgs();
-	birgs     = ALLOCAN(be_irg_t, num_birgs + 1);
+	num_irgs = get_irp_n_irgs();
+	birgs    = ALLOCAN(be_irg_t, num_irgs + 1);
 
 	be_info_init();
 
 	/* First: initialize all birgs */
-	for (i = 0; i < num_birgs; ++i) {
+	num_birgs = 0;
+	for (i = 0; i < num_irgs; ++i) {
 		ir_graph  *irg    = get_irp_irg(i);
-		initialize_birg(&birgs[i], irg, &env);
+		ir_entity *entity = get_irg_entity(irg);
+		if (get_entity_linkage(entity) & IR_LINKAGE_NO_CODEGEN)
+			continue;
+		initialize_birg(&birgs[num_birgs++], irg, &env);
 	}
 	arch_env_handle_intrinsics(arch_env);
 

ir/opt/garbage_collect.c

@@ -123,7 +123,8 @@ static void visit_segment(ir_type *segment)
 	for (i = 0; i < n_entities; ++i) {
 		ir_entity *entity = get_compound_member(segment, i);
 		if (get_entity_visibility(entity) != ir_visibility_external
-				&& !(get_entity_linkage(entity) & IR_LINKAGE_HIDDEN_USER))
+				&& !(get_entity_linkage(entity) & IR_LINKAGE_HIDDEN_USER)
+				&& !(get_entity_linkage(entity) & IR_LINKAGE_NO_CODEGEN))
 			continue;
 
 		visit_entity(entity);

ir/tr/entity.c

@@ -1063,7 +1063,8 @@ int entity_is_externally_visible(const ir_entity *entity)
 int entity_has_definition(const ir_entity *entity)
 {
 	if (is_method_entity(entity)) {
-		return get_entity_irg(entity) != NULL;
+		return get_entity_irg(entity) != NULL
+		    && (get_entity_linkage(entity) & IR_LINKAGE_NO_CODEGEN) == 0;
 	} else {
 		return entity->initializer != NULL
 		    || entity_has_compound_ent_values(entity);