Begin work to move entry point code to Odin itself rather than in C++ side

core/intrinsics/intrinsics.odin

@@ -197,3 +197,8 @@ type_field_index_of :: proc($T: typeid, $name: string) -> uintptr ---
 
 type_equal_proc  :: proc($T: typeid) -> (equal:  proc "contextless" (rawptr, rawptr) -> bool)                 where type_is_comparable(T) ---
 type_hasher_proc :: proc($T: typeid) -> (hasher: proc "contextless" (data: rawptr, seed: uintptr) -> uintptr) where type_is_comparable(T) ---
+
+
+// Internal compiler use only
+
+__entry_point :: proc() ---

src/check_builtin.cpp

@@ -219,6 +219,12 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 		GB_PANIC("Implement built-in procedure: %.*s", LIT(builtin_name));
 		break;
 
+	case BuiltinProc___entry_point:
+		operand->mode = Addressing_NoValue;
+		operand->type = nullptr;
+		mpmc_enqueue(&c->info->intrinsics_entry_point_usage, call);
+		break;
+
 	case BuiltinProc_DIRECTIVE: {
 		ast_node(bd, BasicDirective, ce->proc);
 		String name = bd->name.string;

src/check_decl.cpp

@@ -777,21 +777,23 @@ void check_proc_decl(CheckerContext *ctx, Entity *e, DeclInfo *d) {
 
 
 	if (e->pkg != nullptr && e->token.string == "main") {
-		if (pt->param_count != 0 ||
+		if (e->pkg->kind != Package_Runtime) {
-		    pt->result_count != 0) {
+			if (pt->param_count != 0 ||
-			gbString str = type_to_string(proc_type);
+			    pt->result_count != 0) {
-			error(e->token, "Procedure type of 'main' was expected to be 'proc()', got %s", str);
+				gbString str = type_to_string(proc_type);
-			gb_string_free(str);
+				error(e->token, "Procedure type of 'main' was expected to be 'proc()', got %s", str);
-		}
+				gb_string_free(str);
-		if (pt->calling_convention != default_calling_convention()) {
+			}
-			error(e->token, "Procedure 'main' cannot have a custom calling convention");
+			if (pt->calling_convention != default_calling_convention()) {
-		}
+				error(e->token, "Procedure 'main' cannot have a custom calling convention");
-		pt->calling_convention = default_calling_convention();
+			}
-		if (e->pkg->kind == Package_Init) {
+			pt->calling_convention = default_calling_convention();
-			if (ctx->info->entry_point != nullptr) {
+			if (e->pkg->kind == Package_Init) {
-				error(e->token, "Redeclaration of the entry pointer procedure 'main'");
+				if (ctx->info->entry_point != nullptr) {
-			} else {
+					error(e->token, "Redeclaration of the entry pointer procedure 'main'");
-				ctx->info->entry_point = e;
+				} else {
+					ctx->info->entry_point = e;
+				}
 			}
 		}
 	}
@@ -924,7 +926,9 @@ void check_proc_decl(CheckerContext *ctx, Entity *e, DeclInfo *d) {
 				      "\tother at %s",
 				      LIT(name), token_pos_to_string(pos));
 			} else if (name == "main") {
-				error(d->proc_lit, "The link name 'main' is reserved for internal use");
+				if (d->entity->pkg->kind != Package_Runtime) {
+					error(d->proc_lit, "The link name 'main' is reserved for internal use");
+				}
 			} else {
 				string_map_set(fp, key, e);
 			}

src/checker.cpp

@@ -823,6 +823,7 @@ void init_universal(void) {
 	add_global_bool_constant("ODIN_NO_CRT",                   bc->no_crt);
 	add_global_bool_constant("ODIN_USE_SEPARATE_MODULES",     bc->use_separate_modules);
 	add_global_bool_constant("ODIN_TEST",                     bc->command_kind == Command_test);
+	add_global_bool_constant("ODIN_NO_ENTRY_POINT",           bc->no_entry_point);
 
 
 // Builtin Procedures
@@ -941,6 +942,8 @@ void init_checker_info(CheckerInfo *i) {
 	mutex_init(&i->foreign_mutex);
 
 	semaphore_init(&i->collect_semaphore);
+
+	mpmc_init(&i->intrinsics_entry_point_usage, a, 1<<10); // just waste some memory here, even if it probably never used
 }
 
 void destroy_checker_info(CheckerInfo *i) {
@@ -3677,11 +3680,6 @@ void check_single_global_entity(Checker *c, Entity *e, DeclInfo *d) {
 			error(e->token, "'main' is reserved as the entry point procedure in the initial scope");
 			return;
 		}
-	} else if (pkg->kind == Package_Runtime) {
-		if (e->token.string == "main") {
-			error(e->token, "'main' is reserved as the entry point procedure in the initial scope");
-			return;
-		}
 	}
 
 	check_entity_decl(ctx, e, d, nullptr);
@@ -5437,5 +5435,15 @@ void check_parsed_files(Checker *c) {
 	TIME_SECTION("sort init procedures");
 	check_sort_init_procedures(c);
 
+	if (c->info.intrinsics_entry_point_usage.count > 0) {
+		TIME_SECTION("check intrinsics.__entry_point usage");
+		Ast *node = nullptr;
+		while (mpmc_dequeue(&c->info.intrinsics_entry_point_usage, &node)) {
+			if (c->info.entry_point == nullptr && node != nullptr) {
+				warning(node, "usage of intrinsics.__entry_point will be a no-op");
+			}
+		}
+	}
+
 	TIME_SECTION("type check finish");
 }

src/checker.hpp

@@ -338,6 +338,9 @@ struct CheckerInfo {
 	MPMCQueue<Entity *> required_global_variable_queue;
 	MPMCQueue<Entity *> required_foreign_imports_through_force_queue;
 
+	MPMCQueue<Ast *> intrinsics_entry_point_usage;
+
+
 };
 
 struct CheckerContext {

src/checker_builtin_procs.hpp

@@ -250,6 +250,8 @@ BuiltinProc__type_simple_boolean_end,
 
 BuiltinProc__type_end,
 
+	BuiltinProc___entry_point,
+
 	BuiltinProc_COUNT,
 };
 gb_global BuiltinProc builtin_procs[BuiltinProc_COUNT] = {
@@ -498,5 +500,8 @@ gb_global BuiltinProc builtin_procs[BuiltinProc_COUNT] = {
 	{STR_LIT("type_equal_proc"),  1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("type_hasher_proc"), 1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 
+
 	{STR_LIT(""), 0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
+
+	{STR_LIT("__entry_point"), 0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
 };

src/llvm_backend.cpp

@@ -873,7 +873,7 @@ lbProcedure *lb_create_main_procedure(lbModule *m, lbProcedure *startup_runtime)
 	} else {
 		if (m->info->entry_point != nullptr) {
 			lbValue entry_point = lb_find_procedure_value_from_entity(m, m->info->entry_point);
-			lb_emit_call(p, entry_point, {});
+			lb_emit_call(p, entry_point, {}, ProcInlining_no_inline);
 		}
 	}
 
@@ -1408,6 +1408,7 @@ void lb_generate_code(lbGenerator *gen) {
 	Entity *entry_point = info->entry_point;
 	bool has_dll_main = false;
 	bool has_win_main = false;
+	bool already_has_entry_point = false;
 
 	for_array(i, info->entities) {
 		Entity *e = info->entities[i];
@@ -1425,7 +1426,9 @@ void lb_generate_code(lbGenerator *gen) {
 			if (e->Procedure.is_export ||
 			    (e->Procedure.link_name.len > 0) ||
 			    ((e->scope->flags&ScopeFlag_File) && e->Procedure.link_name.len > 0)) {
-				if (!has_dll_main && name == "DllMain") {
+				if (name == "main" || name == "DllMain" || name == "WinMain" || name == "mainCRTStartup") {
+					already_has_entry_point = true;
+				} else if (!has_dll_main && name == "DllMain") {
 					has_dll_main = true;
 				} else if (!has_win_main && name == "WinMain") {
 					has_win_main = true;
@@ -1643,9 +1646,11 @@ void lb_generate_code(lbGenerator *gen) {
 	}
 
 
-	if (!(build_context.build_mode == BuildMode_DynamicLibrary && !has_dll_main)) {
+	if (!already_has_entry_point) {
-		TIME_SECTION("LLVM main");
+		if (!(build_context.build_mode == BuildMode_DynamicLibrary && !has_dll_main)) {
-		lb_create_main_procedure(default_module, startup_runtime);
+			TIME_SECTION("LLVM main");
+			lb_create_main_procedure(default_module, startup_runtime);
+		}
 	}
 
 	for_array(j, gen->modules.entries) {

src/llvm_backend_proc.cpp

@@ -1965,6 +1965,14 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 			return res;
 		}
 		
+	case BuiltinProc___entry_point:
+		if (p->module->info->entry_point) {
+			lbValue entry_point = lb_find_procedure_value_from_entity(p->module, p->module->info->entry_point);
+			GB_ASSERT(entry_point.value != nullptr);
+			lb_emit_call(p, entry_point, {});
+		}
+		return {};
+
 	case BuiltinProc_syscall:
 		{
 			unsigned arg_count = cast(unsigned)ce->args.count;