Merge remote-tracking branch 'upstream/master' into fix_odin_test

24 files changed, 640 insertions, 204 deletions

diff --git a/src/array.cpp b/src/array.cpp
index ac3727978..d08bd647f 100644
--- a/src/array.cpp
+++ b/src/array.cpp
@@ -89,7 +89,9 @@ template <typename T>
 void slice_init(Slice<T> *s, gbAllocator const &allocator, isize count) {
 	GB_ASSERT(count >= 0);
 	s->data = gb_alloc_array(allocator, T, count);
-	GB_ASSERT(s->data != nullptr);
+	if (count > 0) {
+		GB_ASSERT(s->data != nullptr);
+	}
 	s->count = count;
 }
 
diff --git a/src/bug_report.cpp b/src/bug_report.cpp
index 9a1cb2254..02a2b1ba2 100644
--- a/src/bug_report.cpp
+++ b/src/bug_report.cpp
@@ -17,6 +17,11 @@
 	#include <sys/sysctl.h>

 #endif

 

+#if defined(GB_SYSTEM_OPENBSD)

+	#include <sys/sysctl.h>

+	#include <sys/utsname.h>

+#endif

+

 /*

 	NOTE(Jeroen): This prints the Windows product edition only, to be called from `print_platform_details`.

 */

@@ -242,6 +247,14 @@ void report_ram_info() {
 		if (sysctl(sysctls, 2, &ram_amount, &val_size, NULL, 0) != -1) {

 			gb_printf("%lld MiB\n", ram_amount / gb_megabytes(1));

 		}

+	#elif defined(GB_SYSTEM_OPENBSD)

+		uint64_t ram_amount;

+		size_t   val_size = sizeof(ram_amount);

+

+		int sysctls[] = { CTL_HW, HW_PHYSMEM64 };

+		if (sysctl(sysctls, 2, &ram_amount, &val_size, NULL, 0) != -1) {

+			gb_printf("%lld MiB\n", ram_amount / gb_megabytes(1));

+		}

 	#else

 		gb_printf("Unknown.\n");

 	#endif

@@ -473,11 +486,11 @@ void print_bug_report_help() {
 

 	#elif defined(GB_SYSTEM_LINUX)

 		/*

-			Try to parse `/usr/lib/os-release` for `PRETTY_NAME="Ubuntu 20.04.3 LTS`

+			Try to parse `/etc/os-release` for `PRETTY_NAME="Ubuntu 20.04.3 LTS`

 		*/

 		gbAllocator a = heap_allocator();

 

-		gbFileContents release = gb_file_read_contents(a, 1, "/usr/lib/os-release");

+		gbFileContents release = gb_file_read_contents(a, 1, "/etc/os-release");

 		defer (gb_file_free_contents(&release));

 

 		b32 found = 0;

@@ -643,6 +656,14 @@ void print_bug_report_help() {
 		} else {

 			gb_printf("macOS: Unknown\n");

 		}			

+	#elif defined(GB_SYSTEM_OPENBSD)

+		struct utsname un;

+		

+		if (uname(&un) != -1) {

+			gb_printf("%s %s %s %s\n", un.sysname, un.release, un.version, un.machine);

+		} else {

+			gb_printf("OpenBSD: Unknown\n");    

+		}

 	#else

 		gb_printf("Unknown\n");

 

@@ -657,4 +678,4 @@ void print_bug_report_help() {
 		And RAM info.

 	*/

 	report_ram_info();

-}
\ No newline at end of file
+}

diff --git a/src/build_settings.cpp b/src/build_settings.cpp
index 610e4f847..9cb281656 100644
--- a/src/build_settings.cpp
+++ b/src/build_settings.cpp
@@ -1,4 +1,4 @@
-#if defined(GB_SYSTEM_FREEBSD)
+#if defined(GB_SYSTEM_FREEBSD) || defined(GB_SYSTEM_OPENBSD)
 #include <sys/types.h>
 #include <sys/sysctl.h>
 #endif
@@ -16,6 +16,7 @@ enum TargetOsKind {
 	TargetOs_linux,
 	TargetOs_essence,
 	TargetOs_freebsd,
+	TargetOs_openbsd,
 	
 	TargetOs_wasi,
 	TargetOs_js,
@@ -53,6 +54,7 @@ String target_os_names[TargetOs_COUNT] = {
 	str_lit("linux"),
 	str_lit("essence"),
 	str_lit("freebsd"),
+	str_lit("openbsd"),
 	
 	str_lit("wasi"),
 	str_lit("js"),
@@ -278,7 +280,7 @@ bool global_ignore_warnings(void) {
 }
 
 
-gb_global TargetMetrics target_windows_386 = {
+gb_global TargetMetrics target_windows_i386 = {
 	TargetOs_windows,
 	TargetArch_i386,
 	4,
@@ -294,7 +296,7 @@ gb_global TargetMetrics target_windows_amd64 = {
 	str_lit("e-m:w-i64:64-f80:128-n8:16:32:64-S128"),
 };
 
-gb_global TargetMetrics target_linux_386 = {
+gb_global TargetMetrics target_linux_i386 = {
 	TargetOs_linux,
 	TargetArch_i386,
 	4,
@@ -337,7 +339,7 @@ gb_global TargetMetrics target_darwin_arm64 = {
 	str_lit("e-m:o-i64:64-i128:128-n32:64-S128"), // TODO(bill): Is this correct?
 };
 
-gb_global TargetMetrics target_freebsd_386 = {
+gb_global TargetMetrics target_freebsd_i386 = {
 	TargetOs_freebsd,
 	TargetArch_i386,
 	4,
@@ -354,6 +356,15 @@ gb_global TargetMetrics target_freebsd_amd64 = {
 	str_lit("e-m:w-i64:64-f80:128-n8:16:32:64-S128"),
 };
 
+gb_global TargetMetrics target_openbsd_amd64 = {
+	TargetOs_openbsd,
+	TargetArch_amd64,
+	8,
+	16,
+	str_lit("x86_64-unknown-openbsd-elf"),
+	str_lit("e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"),
+};
+
 gb_global TargetMetrics target_essence_amd64 = {
 	TargetOs_essence,
 	TargetArch_amd64,
@@ -410,13 +421,14 @@ gb_global NamedTargetMetrics named_targets[] = {
 	{ str_lit("darwin_amd64"),        &target_darwin_amd64   },
 	{ str_lit("darwin_arm64"),        &target_darwin_arm64   },
 	{ str_lit("essence_amd64"),       &target_essence_amd64  },
-	{ str_lit("linux_386"),           &target_linux_386      },
+	{ str_lit("linux_i386"),          &target_linux_i386     },
 	{ str_lit("linux_amd64"),         &target_linux_amd64    },
 	{ str_lit("linux_arm64"),         &target_linux_arm64    },
-	{ str_lit("windows_386"),         &target_windows_386    },
+	{ str_lit("windows_i386"),        &target_windows_i386   },
 	{ str_lit("windows_amd64"),       &target_windows_amd64  },
-	{ str_lit("freebsd_386"),         &target_freebsd_386    },
+	{ str_lit("freebsd_i386"),        &target_freebsd_i386   },
 	{ str_lit("freebsd_amd64"),       &target_freebsd_amd64  },
+	{ str_lit("openbsd_amd64"),       &target_openbsd_amd64  },
 	{ str_lit("freestanding_wasm32"), &target_freestanding_wasm32 },
 	{ str_lit("wasi_wasm32"),         &target_wasi_wasm32 },
 	{ str_lit("js_wasm32"),           &target_js_wasm32 },
@@ -722,10 +734,38 @@ String internal_odin_root_dir(void) {
 		len = readlink("/proc/curproc/exe", &path_buf[0], path_buf.count);
 #elif defined(GB_SYSTEM_DRAGONFLYBSD)
 		len = readlink("/proc/curproc/file", &path_buf[0], path_buf.count);
-#else
+#elif defined(GB_SYSTEM_LINUX)
 		len = readlink("/proc/self/exe", &path_buf[0], path_buf.count);
+#elif defined(GB_SYSTEM_OPENBSD)
+		int error;
+		int mib[] = {
+			CTL_KERN,
+			KERN_PROC_ARGS,
+			getpid(),
+			KERN_PROC_ARGV,
+		};
+		// get argv size
+		error = sysctl(mib, 4, NULL, (size_t *) &len, NULL, 0);
+		if (error == -1) {
+			// sysctl error
+			return make_string(nullptr, 0);
+		}
+		// get argv
+		char **argv = (char **)gb_malloc(len);
+		error = sysctl(mib, 4, argv, (size_t *) &len, NULL, 0);
+		if (error == -1) {
+			// sysctl error
+			gb_mfree(argv);
+			return make_string(nullptr, 0);
+		}
+		// copy argv[0] to path_buf
+		len = gb_strlen(argv[0]);
+		if(len < path_buf.count) {
+			gb_memmove(&path_buf[0], argv[0], len);
+		}
+		gb_mfree(argv);
 #endif
-		if(len == 0) {
+		if(len == 0 || len == -1) {
 			return make_string(nullptr, 0);
 		}
 		if (len < path_buf.count) {
@@ -922,6 +962,8 @@ void init_build_context(TargetMetrics *cross_target) {
 			#endif
 		#elif defined(GB_SYSTEM_FREEBSD)
 			metrics = &target_freebsd_amd64;
+		#elif defined(GB_SYSTEM_OPENBSD)
+			metrics = &target_openbsd_amd64;
 		#elif defined(GB_CPU_ARM)
 			metrics = &target_linux_arm64;
 		#else
@@ -929,13 +971,13 @@ void init_build_context(TargetMetrics *cross_target) {
 		#endif
 	#else
 		#if defined(GB_SYSTEM_WINDOWS)
-			metrics = &target_windows_386;
+			metrics = &target_windows_i386;
 		#elif defined(GB_SYSTEM_OSX)
 			#error "Build Error: Unsupported architecture"
 		#elif defined(GB_SYSTEM_FREEBSD)
-			metrics = &target_freebsd_386;
+			metrics = &target_freebsd_i386;
 		#else
-			metrics = &target_linux_386;
+			metrics = &target_linux_i386;
 		#endif
 	#endif
 
@@ -980,6 +1022,9 @@ void init_build_context(TargetMetrics *cross_target) {
 		case TargetOs_freebsd:
 			bc->link_flags = str_lit("-arch x86-64 ");
 			break;
+		case TargetOs_openbsd:
+			bc->link_flags = str_lit("-arch x86-64 ");
+			break;
 		}
 	} else if (bc->metrics.arch == TargetArch_i386) {
 		switch (bc->metrics.os) {
diff --git a/src/check_builtin.cpp b/src/check_builtin.cpp
index c7ada8e03..365d3434f 100644
--- a/src/check_builtin.cpp
+++ b/src/check_builtin.cpp
@@ -223,36 +223,35 @@ void add_objc_proc_type(CheckerContext *c, Ast *call, Type *return_type, Slice<T
 	map_set(&c->info->objc_msgSend_types, call, data);
 	mutex_unlock(&c->info->objc_types_mutex);
 
-	add_package_dependency(c, "runtime", "objc_lookUpClass");
-	add_package_dependency(c, "runtime", "sel_registerName");
-	add_package_dependency(c, "runtime", "objc_allocateClassPair");
-
-	add_package_dependency(c, "runtime", "objc_msgSend");
-	add_package_dependency(c, "runtime", "objc_msgSend_fpret");
-	add_package_dependency(c, "runtime", "objc_msgSend_fp2ret");
-	add_package_dependency(c, "runtime", "objc_msgSend_stret");
+	try_to_add_package_dependency(c, "runtime", "objc_msgSend");
+	try_to_add_package_dependency(c, "runtime", "objc_msgSend_fpret");
+	try_to_add_package_dependency(c, "runtime", "objc_msgSend_fp2ret");
+	try_to_add_package_dependency(c, "runtime", "objc_msgSend_stret");
+}
+
+bool is_constant_string(CheckerContext *c, String const &builtin_name, Ast *expr, String *name_) {
+	Operand op = {};
+	check_expr(c, &op, expr);
+	if (op.mode == Addressing_Constant && op.value.kind == ExactValue_String) {
+		if (name_) *name_ = op.value.value_string;
+		return true;
+	}
+	gbString e = expr_to_string(op.expr);
+	gbString t = type_to_string(op.type);
+	error(op.expr, "'%.*s' expected a constant string value, got %s of type %s", LIT(builtin_name), e, t);
+	gb_string_free(t);
+	gb_string_free(e);
+	return false;
 }
 
 bool check_builtin_objc_procedure(CheckerContext *c, Operand *operand, Ast *call, i32 id, Type *type_hint) {
-	auto const is_constant_string = [](CheckerContext *c, String const &builtin_name, Ast *expr, String *name_) -> bool {
-		Operand op = {};
-		check_expr(c, &op, expr);
-		if (op.mode == Addressing_Constant && op.value.kind == ExactValue_String) {
-			if (name_) *name_ = op.value.value_string;
-			return true;
-		}
-		gbString e = expr_to_string(op.expr);
-		gbString t = type_to_string(op.type);
-		error(op.expr, "'%.*s' expected a constant string value, got %s of type %s", LIT(builtin_name), e, t);
-		gb_string_free(t);
-		gb_string_free(e);
-		return false;
-	};
 	String builtin_name = builtin_procs[id].name;
 
 	if (build_context.metrics.os != TargetOs_darwin) {
-		error(call, "'%.*s' only works on darwin", LIT(builtin_name));
-		return false;
+		// allow on doc generation (e.g. Metal stuff)
+		if (build_context.command_kind != Command_doc && build_context.command_kind != Command_check) {
+			error(call, "'%.*s' only works on darwin", LIT(builtin_name));
+		}
 	}
 
 
@@ -371,6 +370,10 @@ bool check_builtin_objc_procedure(CheckerContext *c, Operand *operand, Ast *call
 
 		}
 		operand->mode = Addressing_Value;
+
+		try_to_add_package_dependency(c, "runtime", "objc_lookUpClass");
+		try_to_add_package_dependency(c, "runtime", "sel_registerName");
+		try_to_add_package_dependency(c, "runtime", "objc_allocateClassPair");
 		return true;
 	} break;
 	}
@@ -949,7 +952,7 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 			mode = Addressing_Constant;
 			value = exact_value_i64(at->EnumeratedArray.count);
 			type = t_untyped_integer;
-		} else if (is_type_slice(op_type) && id == BuiltinProc_len) {
+		} else if ((is_type_slice(op_type) || is_type_relative_slice(op_type)) && id == BuiltinProc_len) {
 			mode = Addressing_Value;
 		} else if (is_type_dynamic_array(op_type)) {
 			mode = Addressing_Value;
@@ -1103,7 +1106,7 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 		
 		Selection sel = lookup_field(type, field_name, false);
 		if (sel.entity == nullptr) {
-			gbString type_str = type_to_string(type);
+			gbString type_str = type_to_string_shorthand(type);
 			error(ce->args[0],
 			      "'%s' has no field named '%.*s'", type_str, LIT(field_name));
 			gb_string_free(type_str);
@@ -1115,7 +1118,7 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 			return false;
 		}
 		if (sel.indirect) {
-			gbString type_str = type_to_string(type);
+			gbString type_str = type_to_string_shorthand(type);
 			error(ce->args[0],
 			      "Field '%.*s' is embedded via a pointer in '%s'", LIT(field_name), type_str);
 			gb_string_free(type_str);
@@ -1176,7 +1179,7 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 		
 		Selection sel = lookup_field(type, field_name, false);
 		if (sel.entity == nullptr) {
-			gbString type_str = type_to_string(type);
+			gbString type_str = type_to_string_shorthand(type);
 			error(ce->args[0],
 			      "'%s' has no field named '%.*s'", type_str, LIT(field_name));
 			gb_string_free(type_str);
@@ -1188,7 +1191,7 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 			return false;
 		}
 		if (sel.indirect) {
-			gbString type_str = type_to_string(type);
+			gbString type_str = type_to_string_shorthand(type);
 			error(ce->args[0],
 			      "Field '%.*s' is embedded via a pointer in '%s'", LIT(field_name), type_str);
 			gb_string_free(type_str);
@@ -3503,6 +3506,7 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 			case TargetOs_linux:
 			case TargetOs_essence:
 			case TargetOs_freebsd:
+			case TargetOs_openbsd:
 				switch (build_context.metrics.arch) {
 				case TargetArch_i386:
 				case TargetArch_amd64:
@@ -4086,6 +4090,18 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 			break;
 		}
 
+	case BuiltinProc_constant_utf16_cstring:
+		{
+			String value = {};
+			if (!is_constant_string(c, builtin_name, ce->args[0], &value)) {
+				return false;
+			}
+			operand->mode = Addressing_Value;
+			operand->type = alloc_type_multi_pointer(t_u16);
+			operand->value = {};
+			break;
+		}
+
 
 	}
 
diff --git a/src/check_decl.cpp b/src/check_decl.cpp
index 45d741532..3fdd944f9 100644
--- a/src/check_decl.cpp
+++ b/src/check_decl.cpp
@@ -174,6 +174,10 @@ void check_init_constant(CheckerContext *ctx, Entity *e, Operand *operand) {
 		return;
 	}
 
+	if (is_type_proc(e->type)) {
+		error(e->token, "Illegal declaration of a constant procedure value");
+	}
+
 	e->parent_proc_decl = ctx->curr_proc_decl;
 
 	e->Constant.value = operand->value;
diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index 7fb0e44f2..614da2368 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -132,6 +132,62 @@ void check_did_you_mean_print(DidYouMeanAnswers *d, char const *prefix = "") {
 	}
 }
 
+void populate_check_did_you_mean_objc_entity(StringSet *set, Entity *e, bool is_type) {
+	if (e->kind != Entity_TypeName) {
+		return;
+	}
+	if (e->TypeName.objc_metadata == nullptr) {
+		return;
+	}
+	TypeNameObjCMetadata *objc_metadata = e->TypeName.objc_metadata;
+	Type *t = base_type(e->type);
+	GB_ASSERT(t->kind == Type_Struct);
+
+	if (is_type) {
+		for_array(i, objc_metadata->type_entries) {
+			String name = objc_metadata->type_entries[i].name;
+			string_set_add(set, name);
+		}
+	} else {
+		for_array(i, objc_metadata->value_entries) {
+			String name = objc_metadata->value_entries[i].name;
+			string_set_add(set, name);
+		}
+	}
+
+	for_array(i, t->Struct.fields) {
+		Entity *f = t->Struct.fields[i];
+		if (f->flags & EntityFlag_Using && f->type != nullptr) {
+			if (f->type->kind == Type_Named && f->type->Named.type_name) {
+				populate_check_did_you_mean_objc_entity(set, f->type->Named.type_name, is_type);
+			}
+		}
+	}
+}
+
+
+void check_did_you_mean_objc_entity(String const &name, Entity *e, bool is_type, char const *prefix = "") {
+	ERROR_BLOCK();
+	GB_ASSERT(e->kind == Entity_TypeName);
+	GB_ASSERT(e->TypeName.objc_metadata != nullptr);
+	auto *objc_metadata = e->TypeName.objc_metadata;
+	mutex_lock(objc_metadata->mutex);
+	defer (mutex_unlock(objc_metadata->mutex));
+
+	StringSet set = {};
+	string_set_init(&set, heap_allocator());
+	defer (string_set_destroy(&set));
+	populate_check_did_you_mean_objc_entity(&set, e, is_type);
+
+
+	DidYouMeanAnswers d = did_you_mean_make(heap_allocator(), set.entries.count, name);
+	defer (did_you_mean_destroy(&d));
+	for_array(i, set.entries) {
+		did_you_mean_append(&d, set.entries[i].value);
+	}
+	check_did_you_mean_print(&d, prefix);
+}
+
 void check_did_you_mean_type(String const &name, Array<Entity *> const &fields, char const *prefix = "") {
 	ERROR_BLOCK();
 
@@ -144,6 +200,7 @@ void check_did_you_mean_type(String const &name, Array<Entity *> const &fields,
 	check_did_you_mean_print(&d, prefix);
 }
 
+
 void check_did_you_mean_type(String const &name, Slice<Entity *> const &fields, char const *prefix = "") {
 	ERROR_BLOCK();
 
@@ -4413,14 +4470,19 @@ Entity *check_selector(CheckerContext *c, Operand *operand, Ast *node, Type *typ
 
 	if (entity == nullptr) {
 		gbString op_str   = expr_to_string(op_expr);
-		gbString type_str = type_to_string(operand->type);
+		gbString type_str = type_to_string_shorthand(operand->type);
 		gbString sel_str  = expr_to_string(selector);
 		error(op_expr, "'%s' of type '%s' has no field '%s'", op_str, type_str, sel_str);
 
 		if (operand->type != nullptr && selector->kind == Ast_Ident) {
 			String const &name = selector->Ident.token.string;
 			Type *bt = base_type(operand->type);
-			if (bt->kind == Type_Struct) {
+			if (operand->type->kind == Type_Named &&
+			    operand->type->Named.type_name &&
+			    operand->type->Named.type_name->kind == Entity_TypeName &&
+			    operand->type->Named.type_name->TypeName.objc_metadata) {
+				check_did_you_mean_objc_entity(name, operand->type->Named.type_name, operand->mode == Addressing_Type);
+			} else if (bt->kind == Type_Struct) {
 				check_did_you_mean_type(name, bt->Struct.fields);
 			} else if (bt->kind == Type_Enum) {
 				check_did_you_mean_type(name, bt->Enum.fields);
@@ -4449,7 +4511,7 @@ Entity *check_selector(CheckerContext *c, Operand *operand, Ast *node, Type *typ
 		}
 
 		gbString op_str   = expr_to_string(op_expr);
-		gbString type_str = type_to_string(operand->type);
+		gbString type_str = type_to_string_shorthand(operand->type);
 		gbString sel_str  = expr_to_string(selector);
 		error(op_expr, "Cannot access non-constant field '%s' from '%s'", sel_str, op_str);
 		gb_string_free(sel_str);
@@ -4474,7 +4536,7 @@ Entity *check_selector(CheckerContext *c, Operand *operand, Ast *node, Type *typ
 		}
 
 		gbString op_str   = expr_to_string(op_expr);
-		gbString type_str = type_to_string(operand->type);
+		gbString type_str = type_to_string_shorthand(operand->type);
 		gbString sel_str  = expr_to_string(selector);
 		error(op_expr, "Cannot access non-constant field '%s' from '%s'", sel_str, op_str);
 		gb_string_free(sel_str);
@@ -4487,7 +4549,7 @@ Entity *check_selector(CheckerContext *c, Operand *operand, Ast *node, Type *typ
 
 	if (expr_entity != nullptr && is_type_polymorphic(expr_entity->type)) {
 		gbString op_str   = expr_to_string(op_expr);
-		gbString type_str = type_to_string(operand->type);
+		gbString type_str = type_to_string_shorthand(operand->type);
 		gbString sel_str  = expr_to_string(selector);
 		error(op_expr, "Cannot access field '%s' from non-specialized polymorphic type '%s'", sel_str, op_str);
 		gb_string_free(sel_str);
@@ -9774,6 +9836,9 @@ gbString write_expr_to_string(gbString str, Ast *node, bool shorthand) {
 		if (f->flags&FieldFlag_const) {
 			str = gb_string_appendc(str, "#const ");
 		}
+		if (f->flags&FieldFlag_subtype) {
+			str = gb_string_appendc(str, "#subtype ");
+		}
 
 		for_array(i, f->names) {
 			Ast *name = f->names[i];
diff --git a/src/check_type.cpp b/src/check_type.cpp
index 976bb7f42..64fb67723 100644
--- a/src/check_type.cpp
+++ b/src/check_type.cpp
@@ -144,6 +144,7 @@ void check_struct_fields(CheckerContext *ctx, Ast *node, Slice<Entity *> *fields
 		}
 
 		bool is_using = (p->flags&FieldFlag_using) != 0;
+		bool is_subtype = (p->flags&FieldFlag_subtype) != 0;
 
 		for_array(j, p->names) {
 			Ast *name = p->names[j];
@@ -158,6 +159,9 @@ void check_struct_fields(CheckerContext *ctx, Ast *node, Slice<Entity *> *fields
 			Entity *field = alloc_entity_field(ctx->scope, name_token, type, is_using, field_src_index);
 			add_entity(ctx, ctx->scope, name, field);
 			field->Variable.field_group_index = field_group_index;
+			if (is_subtype) {
+				field->flags |= EntityFlag_Subtype;
+			}
 
 			if (j == 0) {
 				field->Variable.docs = docs;
@@ -194,6 +198,20 @@ void check_struct_fields(CheckerContext *ctx, Ast *node, Slice<Entity *> *fields
 
 			populate_using_entity_scope(ctx, node, p, type);
 		}
+
+		if (is_subtype && p->names.count > 0) {
+			Type *first_type = fields_array[fields_array.count-1]->type;
+			Type *t = base_type(type_deref(first_type));
+
+			if (!does_field_type_allow_using(t) &&
+			    p->names.count >= 1 &&
+			    p->names[0]->kind == Ast_Ident) {
+				Token name_token = p->names[0]->Ident.token;
+				gbString type_str = type_to_string(first_type);
+				error(name_token, "'subtype' cannot be applied to the field '%.*s' of type '%s'", LIT(name_token.string), type_str);
+				gb_string_free(type_str);
+			}
+		}
 	}
 	
 	*fields = slice_from_array(fields_array);
diff --git a/src/checker.cpp b/src/checker.cpp
index 81e6f256e..5a7ece263 100644
--- a/src/checker.cpp
+++ b/src/checker.cpp
@@ -225,8 +225,8 @@ bool decl_info_has_init(DeclInfo *d) {
 Scope *create_scope(CheckerInfo *info, Scope *parent, isize init_elements_capacity=DEFAULT_SCOPE_CAPACITY) {
 	Scope *s = gb_alloc_item(permanent_allocator(), Scope);
 	s->parent = parent;
-	string_map_init(&s->elements, permanent_allocator(), init_elements_capacity);
-	ptr_set_init(&s->imported, permanent_allocator(), 0);
+	string_map_init(&s->elements, heap_allocator(), init_elements_capacity);
+	ptr_set_init(&s->imported, heap_allocator(), 0);
 	mutex_init(&s->mutex);
 
 	if (parent != nullptr && parent != builtin_pkg->scope) {
@@ -733,12 +733,25 @@ void add_package_dependency(CheckerContext *c, char const *package_name, char co
 	String n = make_string_c(name);
 	AstPackage *p = get_core_package(&c->checker->info, make_string_c(package_name));
 	Entity *e = scope_lookup(p->scope, n);
-	e->flags |= EntityFlag_Used;
 	GB_ASSERT_MSG(e != nullptr, "%s", name);
 	GB_ASSERT(c->decl != nullptr);
+	e->flags |= EntityFlag_Used;
+	add_dependency(c->info, c->decl, e);
+}
+
+void try_to_add_package_dependency(CheckerContext *c, char const *package_name, char const *name) {
+	String n = make_string_c(name);
+	AstPackage *p = get_core_package(&c->checker->info, make_string_c(package_name));
+	Entity *e = scope_lookup(p->scope, n);
+	if (e == nullptr) {
+		return;
+	}
+	GB_ASSERT(c->decl != nullptr);
+	e->flags |= EntityFlag_Used;
 	add_dependency(c->info, c->decl, e);
 }
 
+
 void add_declaration_dependency(CheckerContext *c, Entity *e) {
 	if (e == nullptr) {
 		return;
@@ -893,6 +906,7 @@ void init_universal(void) {
 			{"Linux",        TargetOs_linux},
 			{"Essence",      TargetOs_essence},
 			{"FreeBSD",      TargetOs_freebsd},
+			{"OpenBSD",      TargetOs_openbsd},
 			{"WASI",         TargetOs_wasi},
 			{"JS",           TargetOs_js},
 			{"Freestanding", TargetOs_freestanding},
diff --git a/src/checker_builtin_procs.hpp b/src/checker_builtin_procs.hpp
index 19fa94ee6..cba952ddf 100644
--- a/src/checker_builtin_procs.hpp
+++ b/src/checker_builtin_procs.hpp
@@ -258,6 +258,9 @@ BuiltinProc__type_end,
 	BuiltinProc_objc_register_selector,
 	BuiltinProc_objc_register_class,
 
+	BuiltinProc_constant_utf16_cstring,
+
+
 	BuiltinProc_COUNT,
 };
 gb_global BuiltinProc builtin_procs[BuiltinProc_COUNT] = {
@@ -517,4 +520,7 @@ gb_global BuiltinProc builtin_procs[BuiltinProc_COUNT] = {
 	{STR_LIT("objc_find_class"),        1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("objc_register_selector"), 1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("objc_register_class"),    1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+
+	{STR_LIT("constant_utf16_cstring"), 1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+
 };
diff --git a/src/common.cpp b/src/common.cpp
index ab2a46118..aaacda04b 100644
--- a/src/common.cpp
+++ b/src/common.cpp
@@ -848,7 +848,7 @@ ReadDirectoryError read_directory(String path, Array<FileInfo> *fi) {
 
 	return ReadDirectory_None;
 }
-#elif defined(GB_SYSTEM_LINUX) || defined(GB_SYSTEM_OSX) || defined(GB_SYSTEM_FREEBSD)
+#elif defined(GB_SYSTEM_LINUX) || defined(GB_SYSTEM_OSX) || defined(GB_SYSTEM_FREEBSD) || defined(GB_SYSTEM_OPENBSD)
 
 #include <dirent.h>
 
@@ -1021,7 +1021,7 @@ LoadedFileError load_file_32(char const *fullpath, LoadedFile *memory_mapped_fil
 	#endif
 	}
 	
-	gbFileContents fc = gb_file_read_contents(heap_allocator(), true, fullpath);
+	gbFileContents fc = gb_file_read_contents(permanent_allocator(), true, fullpath);
 
 	if (fc.size > I32_MAX) {
 		err = LoadedFile_FileTooLarge;
diff --git a/src/common_memory.cpp b/src/common_memory.cpp
index 096c35b5c..953462077 100644
--- a/src/common_memory.cpp
+++ b/src/common_memory.cpp
@@ -139,6 +139,7 @@ struct PlatformMemoryBlock {
 };
 
 
+gb_global std::atomic<isize> global_platform_memory_total_usage;
 gb_global PlatformMemoryBlock global_platform_memory_block_sentinel;
 
 PlatformMemoryBlock *platform_virtual_memory_alloc(isize total_size);
@@ -158,10 +159,17 @@ void platform_virtual_memory_protect(void *memory, isize size);
 
 	PlatformMemoryBlock *platform_virtual_memory_alloc(isize total_size) {
 		PlatformMemoryBlock *pmblock = (PlatformMemoryBlock *)VirtualAlloc(0, total_size, MEM_RESERVE|MEM_COMMIT, PAGE_READWRITE);
-		GB_ASSERT_MSG(pmblock != nullptr, "Out of Virtual Memory, oh no...");
+		if (pmblock == nullptr) {
+			gb_printf_err("Out of Virtual memory, oh no...\n");
+			gb_printf_err("Requested: %lld bytes\n", cast(long long)total_size);
+			gb_printf_err("Total Usage: %lld bytes\n", cast(long long)global_platform_memory_total_usage);
+			GB_ASSERT_MSG(pmblock != nullptr, "Out of Virtual Memory, oh no...");
+		}
+		global_platform_memory_total_usage += total_size;
 		return pmblock;
 	}
 	void platform_virtual_memory_free(PlatformMemoryBlock *block) {
+		global_platform_memory_total_usage -= block->total_size;
 		GB_ASSERT(VirtualFree(block, 0, MEM_RELEASE));
 	}
 	void platform_virtual_memory_protect(void *memory, isize size) {
@@ -180,11 +188,18 @@ void platform_virtual_memory_protect(void *memory, isize size);
 	
 	PlatformMemoryBlock *platform_virtual_memory_alloc(isize total_size) {
 		PlatformMemoryBlock *pmblock = (PlatformMemoryBlock *)mmap(nullptr, total_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
-		GB_ASSERT_MSG(pmblock != nullptr, "Out of Virtual Memory, oh no...");
+		if (pmblock == nullptr) {
+			gb_printf_err("Out of Virtual memory, oh no...\n");
+			gb_printf_err("Requested: %lld bytes\n", cast(long long)total_size);
+			gb_printf_err("Total Usage: %lld bytes\n", cast(long long)global_platform_memory_total_usage);
+			GB_ASSERT_MSG(pmblock != nullptr, "Out of Virtual Memory, oh no...");
+		}
+		global_platform_memory_total_usage += total_size;
 		return pmblock;
 	}
 	void platform_virtual_memory_free(PlatformMemoryBlock *block) {
 		isize size = block->total_size;
+		global_platform_memory_total_usage -= size;
 		munmap(block, size);
 	}
 	void platform_virtual_memory_protect(void *memory, isize size) {
diff --git a/src/entity.cpp b/src/entity.cpp
index df8ee3faa..f5720293f 100644
--- a/src/entity.cpp
+++ b/src/entity.cpp
@@ -74,6 +74,7 @@ enum EntityFlag : u64 {
 
 	EntityFlag_Test          = 1ull<<30,
 	EntityFlag_Init          = 1ull<<31,
+	EntityFlag_Subtype       = 1ull<<32,
 	
 	EntityFlag_CustomLinkName = 1ull<<40,
 	EntityFlag_CustomLinkage_Internal = 1ull<<41,
@@ -86,6 +87,10 @@ enum EntityFlag : u64 {
 	EntityFlag_Overridden    = 1ull<<63,
 };
 
+enum : u64 {
+	EntityFlags_IsSubtype = EntityFlag_Using|EntityFlag_Subtype,
+};
+
 enum EntityState : u32 {
 	EntityState_Unresolved = 0,
 	EntityState_InProgress = 1,
diff --git a/src/exact_value.cpp b/src/exact_value.cpp
index fd90278e5..f6df48951 100644
--- a/src/exact_value.cpp
+++ b/src/exact_value.cpp
@@ -50,9 +50,9 @@ struct ExactValue {
 	union {
 		bool           value_bool;
 		String         value_string;
-		BigInt         value_integer; // NOTE(bill): This must be an integer and not a pointer
+		BigInt         value_integer;
 		f64            value_float;
-		i64            value_pointer;
+		i64            value_pointer; // NOTE(bill): This must be an integer and not a pointer
 		Complex128    *value_complex;
 		Quaternion256 *value_quaternion;
 		Ast *          value_compound;
@@ -630,6 +630,9 @@ void match_exact_values(ExactValue *x, ExactValue *y) {
 	case ExactValue_Bool:
 	case ExactValue_String:
 	case ExactValue_Quaternion:
+	case ExactValue_Pointer:
+	case ExactValue_Procedure:
+	case ExactValue_Typeid:
 		return;
 
 	case ExactValue_Integer:
@@ -671,9 +674,6 @@ void match_exact_values(ExactValue *x, ExactValue *y) {
 			return;
 		}
 		break;
-
-	case ExactValue_Procedure:
-		return;
 	}
 
 	compiler_error("match_exact_values: How'd you get here? Invalid ExactValueKind %d", x->kind);
@@ -932,6 +932,17 @@ bool compare_exact_values(TokenKind op, ExactValue x, ExactValue y) {
 		break;
 	}
 
+	case ExactValue_Pointer: {
+		switch (op) {
+		case Token_CmpEq: return x.value_pointer == y.value_pointer;
+		case Token_NotEq: return x.value_pointer != y.value_pointer;
+		case Token_Lt:    return x.value_pointer <  y.value_pointer;
+		case Token_LtEq:  return x.value_pointer <= y.value_pointer;
+		case Token_Gt:    return x.value_pointer >  y.value_pointer;
+		case Token_GtEq:  return x.value_pointer >= y.value_pointer;
+		}
+	}
+
 	case ExactValue_Typeid:
 		switch (op) {
 		case Token_CmpEq: return are_types_identical(x.value_typeid, y.value_typeid);
diff --git a/src/gb/gb.h b/src/gb/gb.h
index d9bf09436..b72a893f7 100644
--- a/src/gb/gb.h
+++ b/src/gb/gb.h
@@ -79,6 +79,10 @@ extern "C" {
 		#ifndef GB_SYSTEM_FREEBSD
 		#define GB_SYSTEM_FREEBSD 1
 		#endif
+	#elif defined(__OpenBSD__)
+		#ifndef GB_SYSTEM_OPENBSD
+		#define GB_SYSTEM_OPENBSD 1
+		#endif
 	#else
 		#error This UNIX operating system is not supported
 	#endif
@@ -199,7 +203,7 @@ extern "C" {
 	#endif
 	#include <stdlib.h> // NOTE(bill): malloc on linux
 	#include <sys/mman.h>
-	#if !defined(GB_SYSTEM_OSX) && !defined(__FreeBSD__)
+	#if !defined(GB_SYSTEM_OSX) && !defined(__FreeBSD__) && !defined(__OpenBSD__)
 		#include <sys/sendfile.h>
 	#endif
 	#include <sys/stat.h>
@@ -235,6 +239,12 @@ extern "C" {
 	#define sendfile(out, in, offset, count) sendfile(out, in, offset, count, NULL, NULL, 0)
 #endif
 
+#if defined(GB_SYSTEM_OPENBSD)
+	#include <stdio.h>
+	#include <pthread_np.h>
+	#define lseek64 lseek
+#endif
+    
 #if defined(GB_SYSTEM_UNIX)
 	#include <semaphore.h>
 #endif
@@ -783,6 +793,13 @@ typedef struct gbAffinity {
 	isize thread_count;
 	isize threads_per_core;
 } gbAffinity;
+#elif defined(GB_SYSTEM_OPENBSD)
+typedef struct gbAffinity {
+	b32   is_accurate;
+	isize core_count;
+	isize thread_count;
+	isize threads_per_core;
+} gbAffinity;
 #else
 #error TODO(bill): Unknown system
 #endif
@@ -3682,6 +3699,30 @@ isize gb_affinity_thread_count_for_core(gbAffinity *a, isize core) {
 	GB_ASSERT(0 <= core && core < a->core_count);
 	return a->threads_per_core;
 }
+
+#elif defined(GB_SYSTEM_OPENBSD)
+#include <unistd.h>
+
+void gb_affinity_init(gbAffinity *a) {
+	a->core_count       = sysconf(_SC_NPROCESSORS_ONLN);
+	a->threads_per_core = 1;
+	a->is_accurate      = a->core_count > 0;
+	a->core_count       = a->is_accurate ? a->core_count : 1;
+	a->thread_count     = a->core_count;
+}
+
+void gb_affinity_destroy(gbAffinity *a) {
+	gb_unused(a);
+}
+
+b32 gb_affinity_set(gbAffinity *a, isize core, isize thread_index) {
+	return true;
+}
+
+isize gb_affinity_thread_count_for_core(gbAffinity *a, isize core) {
+	GB_ASSERT(0 <= core && core < a->core_count);
+	return a->threads_per_core;
+}
 #else
 #error TODO(bill): Unknown system
 #endif
@@ -6025,7 +6066,7 @@ gbFileTime gb_file_last_write_time(char const *filepath) {
 gb_inline b32 gb_file_copy(char const *existing_filename, char const *new_filename, b32 fail_if_exists) {
 #if defined(GB_SYSTEM_OSX)
 	return copyfile(existing_filename, new_filename, NULL, COPYFILE_DATA) == 0;
-#else
+#elif defined(GB_SYSTEM_LINUX) || defined(GB_SYSTEM_FREEBSD)
 	isize size;
 	int existing_fd = open(existing_filename, O_RDONLY, 0);
 	int new_fd      = open(new_filename, O_WRONLY|O_CREAT, 0666);
@@ -6042,6 +6083,49 @@ gb_inline b32 gb_file_copy(char const *existing_filename, char const *new_filena
 	close(existing_fd);
 
 	return size == stat_existing.st_size;
+#else
+	int new_flags = O_WRONLY | O_CREAT;
+	if (fail_if_exists) {
+		new_flags |= O_EXCL;
+	}
+	int existing_fd = open(existing_filename, O_RDONLY, 0);
+	int new_fd      = open(new_filename, new_flags, 0666);
+
+	struct stat stat_existing;
+	if (fstat(existing_fd, &stat_existing) == -1) {
+		return 0;
+	}
+
+	size_t bsize = stat_existing.st_blksize > BUFSIZ ? stat_existing.st_blksize : BUFSIZ;
+	char *buf = (char *)malloc(bsize);
+	if (buf == NULL) {
+		close(new_fd);
+		close(existing_fd);
+		return 0;
+	}
+
+	isize size = 0;
+	ssize_t nread, nwrite, offset;
+	while ((nread = read(existing_fd, buf, bsize)) != -1 && nread != 0) {
+		for (offset = 0; nread; nread -= nwrite, offset += nwrite) {
+			if ((nwrite = write(new_fd, buf + offset, nread)) == -1 || nwrite == 0) {
+				free(buf);
+				close(new_fd);
+				close(existing_fd);
+				return 0;
+			}
+			size += nwrite;
+		}
+	}
+	
+	free(buf);
+	close(new_fd);
+	close(existing_fd);
+
+	if (nread == -1) {
+		return 0;
+	}
+	return size == stat_existing.st_size;
 #endif
 }
 
@@ -6093,6 +6177,7 @@ gbFileContents gb_file_read_contents(gbAllocator a, b32 zero_terminate, char con
 }
 
 void gb_file_free_contents(gbFileContents *fc) {
+    if (fc == NULL || fc->size == 0) return;
 	GB_ASSERT_NOT_NULL(fc->data);
 	gb_free(fc->allocator, fc->data);
 	fc->data = NULL;
diff --git a/src/llvm_backend.cpp b/src/llvm_backend.cpp
index 07b8e97b2..3694f186a 100644
--- a/src/llvm_backend.cpp
+++ b/src/llvm_backend.cpp
@@ -1295,6 +1295,11 @@ void lb_generate_code(lbGenerator *gen) {
 		reloc_mode = LLVMRelocPIC;
 	}
 
+	if (build_context.metrics.os == TargetOs_openbsd) {
+		// Always use PIC for OpenBSD: it defaults to PIE
+		reloc_mode = LLVMRelocPIC;
+	}
+
 	for_array(i, gen->modules.entries) {
 		target_machines[i] = LLVMCreateTargetMachine(
 			target, target_triple, llvm_cpu,
diff --git a/src/llvm_backend_debug.cpp b/src/llvm_backend_debug.cpp
index ff1c5c7dc..b91f32bfc 100644
--- a/src/llvm_backend_debug.cpp
+++ b/src/llvm_backend_debug.cpp
@@ -962,7 +962,7 @@ void lb_add_debug_local_variable(lbProcedure *p, LLVMValueRef ptr, Type *type, T
 	LLVMMetadataRef llvm_debug_loc = lb_debug_location_from_token_pos(p, token.pos);
 	LLVMMetadataRef llvm_expr = LLVMDIBuilderCreateExpression(m->debug_builder, nullptr, 0);
 	lb_set_llvm_metadata(m, ptr, llvm_expr);
-	LLVMDIBuilderInsertDbgValueAtEnd(m->debug_builder, storage, var_info, llvm_expr, llvm_debug_loc, block);
+	LLVMDIBuilderInsertDeclareAtEnd(m->debug_builder, storage, var_info, llvm_expr, llvm_debug_loc, block);
 }
 
 
diff --git a/src/llvm_backend_expr.cpp b/src/llvm_backend_expr.cpp
index 844deb43c..026350440 100644
--- a/src/llvm_backend_expr.cpp
+++ b/src/llvm_backend_expr.cpp
@@ -2202,6 +2202,21 @@ lbValue lb_emit_comp(lbProcedure *p, TokenKind op_kind, lbValue left, lbValue ri
 		}
 	}
 
+	if (is_type_matrix(a) && (op_kind == Token_CmpEq || op_kind == Token_NotEq)) {
+		Type *tl = base_type(a);
+		lbValue lhs = lb_address_from_load_or_generate_local(p, left);
+		lbValue rhs = lb_address_from_load_or_generate_local(p, right);
+
+
+		// TODO(bill): Test to see if this is actually faster!!!!
+		auto args = array_make<lbValue>(permanent_allocator(), 3);
+		args[0] = lb_emit_conv(p, lhs, t_rawptr);
+		args[1] = lb_emit_conv(p, rhs, t_rawptr);
+		args[2] = lb_const_int(p->module, t_int, type_size_of(tl));
+		lbValue val = lb_emit_runtime_call(p, "memory_compare", args);
+		lbValue res = lb_emit_comp(p, op_kind, val, lb_const_nil(p->module, val.type));
+		return lb_emit_conv(p, res, t_bool);
+	}
 	if (is_type_array(a) || is_type_enumerated_array(a)) {
 		Type *tl = base_type(a);
 		lbValue lhs = lb_address_from_load_or_generate_local(p, left);
diff --git a/src/llvm_backend_proc.cpp b/src/llvm_backend_proc.cpp
index 261e2819c..eb6c89b85 100644
--- a/src/llvm_backend_proc.cpp
+++ b/src/llvm_backend_proc.cpp
@@ -57,6 +57,7 @@ void lb_mem_copy_non_overlapping(lbProcedure *p, lbValue dst, lbValue src, lbVal
 	LLVMBuildCall(p->builder, ip, args, gb_count_of(args), "");
 }
 
+
 lbProcedure *lb_create_procedure(lbModule *m, Entity *entity, bool ignore_body) {
 	GB_ASSERT(entity != nullptr);
 	GB_ASSERT(entity->kind == Entity_Procedure);
@@ -163,14 +164,6 @@ lbProcedure *lb_create_procedure(lbModule *m, Entity *entity, bool ignore_body)
 		break;
 	}
 
-
-
-	// lbCallingConventionKind cc_kind = lbCallingConvention_C;
-	// // TODO(bill): Clean up this logic
-	// if (build_context.metrics.os != TargetOs_js)  {
-	// 	cc_kind = lb_calling_convention_map[pt->Proc.calling_convention];
-	// }
-	// LLVMSetFunctionCallConv(p->value, cc_kind);
 	lbValue proc_value = {p->value, p->type};
 	lb_add_entity(m, entity,  proc_value);
 	lb_add_member(m, p->name, proc_value);
@@ -1049,7 +1042,7 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 			return lb_string_len(p, v);
 		} else if (is_type_array(t)) {
 			GB_PANIC("Array lengths are constant");
-		} else if (is_type_slice(t)) {
+		} else if (is_type_slice(t) || is_type_relative_slice(t)) {
 			return lb_slice_len(p, v);
 		} else if (is_type_dynamic_array(t)) {
 			return lb_dynamic_array_len(p, v);
@@ -1075,7 +1068,7 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 			GB_PANIC("Unreachable");
 		} else if (is_type_array(t)) {
 			GB_PANIC("Array lengths are constant");
-		} else if (is_type_slice(t)) {
+		} else if (is_type_slice(t) || is_type_relative_slice(t)) {
 			return lb_slice_len(p, v);
 		} else if (is_type_dynamic_array(t)) {
 			return lb_dynamic_array_cap(p, v);
@@ -2122,6 +2115,77 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 	case BuiltinProc_objc_find_class:        return lb_handle_objc_find_class(p, expr);
 	case BuiltinProc_objc_register_selector: return lb_handle_objc_register_selector(p, expr);
 	case BuiltinProc_objc_register_class:    return lb_handle_objc_register_class(p, expr);
+
+
+	case BuiltinProc_constant_utf16_cstring:
+		{
+			auto const encode_surrogate_pair = [](Rune r, u16 *r1, u16 *r2) {
+				if (r < 0x10000 || r > 0x10ffff) {
+					*r1 = 0xfffd;
+					*r2 = 0xfffd;
+				} else {
+					r -= 0x10000;
+					*r1 = 0xd800 + ((r>>10)&0x3ff);
+					*r2 = 0xdc00 + (r&0x3ff);
+				}
+			};
+
+			lbModule *m = p->module;
+
+			auto tav = type_and_value_of_expr(ce->args[0]);
+			GB_ASSERT(tav.value.kind == ExactValue_String);
+			String value = tav.value.value_string;
+
+			LLVMTypeRef llvm_u16 = lb_type(m, t_u16);
+
+			isize max_len = value.len*2 + 1;
+			LLVMValueRef *buffer = gb_alloc_array(temporary_allocator(), LLVMValueRef, max_len);
+			isize n = 0;
+			while (value.len > 0) {
+				Rune r = 0;
+				isize w = gb_utf8_decode(value.text, value.len, &r);
+				value.text += w;
+				value.len  -= w;
+				if ((0 <= r && r < 0xd800) || (0xe000 <= r && r < 0x10000)) {
+					buffer[n++] = LLVMConstInt(llvm_u16, cast(u16)r, false);
+				} else if (0x10000 <= r && r <= 0x10ffff) {
+					u16 r1, r2;
+					encode_surrogate_pair(r, &r1, &r2);
+					buffer[n++] = LLVMConstInt(llvm_u16, r1, false);
+					buffer[n++] = LLVMConstInt(llvm_u16, r2, false);
+				} else {
+					buffer[n++] = LLVMConstInt(llvm_u16, 0xfffd, false);
+				}
+			}
+
+			buffer[n++] = LLVMConstInt(llvm_u16, 0, false);
+
+			LLVMValueRef array = LLVMConstArray(llvm_u16, buffer, cast(unsigned int)n);
+
+			char *name = nullptr;
+			{
+				isize max_len = 7+8+1;
+				name = gb_alloc_array(permanent_allocator(), char, max_len);
+				u32 id = m->gen->global_array_index.fetch_add(1);
+				isize len = gb_snprintf(name, max_len, "csbs$%x", id);
+				len -= 1;
+			}
+			LLVMValueRef global_data = LLVMAddGlobal(m->mod, LLVMTypeOf(array), name);
+			LLVMSetInitializer(global_data, array);
+			LLVMSetLinkage(global_data, LLVMInternalLinkage);
+
+
+
+			LLVMValueRef indices[] = {
+				LLVMConstInt(lb_type(m, t_u32), 0, false),
+				LLVMConstInt(lb_type(m, t_u32), 0, false),
+			};
+			lbValue res = {};
+			res.type = tv.type;
+			res.value = LLVMBuildInBoundsGEP(p->builder, global_data, indices, gb_count_of(indices), "");
+			return res;
+
+		}
 	}
 
 	GB_PANIC("Unhandled built-in procedure %.*s", LIT(builtin_procs[id].name));
diff --git a/src/llvm_backend_utility.cpp b/src/llvm_backend_utility.cpp
index 98b7e07f0..431cfea9b 100644
--- a/src/llvm_backend_utility.cpp
+++ b/src/llvm_backend_utility.cpp
@@ -1373,7 +1373,7 @@ lbValue lb_slice_elem(lbProcedure *p, lbValue slice) {
 	return lb_emit_struct_ev(p, slice, 0);
 }
 lbValue lb_slice_len(lbProcedure *p, lbValue slice) {
-	GB_ASSERT(is_type_slice(slice.type));
+	GB_ASSERT(is_type_slice(slice.type) || is_type_relative_slice(slice.type));
 	return lb_emit_struct_ev(p, slice, 1);
 }
 lbValue lb_dynamic_array_elem(lbProcedure *p, lbValue da) {
diff --git a/src/main.cpp b/src/main.cpp
index 014fbf822..aab695de2 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -384,7 +384,7 @@ i32 linker_stage(lbGenerator *gen) {
 			// NOTE(zangent): Sometimes, you have to use -framework on MacOS.
 			//   This allows you to specify '-f' in a #foreign_system_library,
 			//   without having to implement any new syntax specifically for MacOS.
-			#if defined(GB_SYSTEM_OSX)
+			if (build_context.metrics.os == TargetOs_darwin) {
 				if (string_ends_with(lib, str_lit(".framework"))) {
 					// framework thingie
 					String lib_name = lib;
@@ -400,14 +400,14 @@ i32 linker_stage(lbGenerator *gen) {
 					// dynamic or static system lib, just link regularly searching system library paths
 					lib_str = gb_string_append_fmt(lib_str, " -l%.*s ", LIT(lib));
 				}
-			#else
+			} else {
 				// NOTE(vassvik): static libraries (.a files) in linux can be linked to directly using the full path,
 				//                since those are statically linked to at link time. shared libraries (.so) has to be
 				//                available at runtime wherever the executable is run, so we make require those to be
 				//                local to the executable (unless the system collection is used, in which case we search
 				//                the system library paths for the library file).
-				if (string_ends_with(lib, str_lit(".a"))) {
-					// static libs, absolute full path relative to the file in which the lib was imported from
+				if (string_ends_with(lib, str_lit(".a")) || string_ends_with(lib, str_lit(".o"))) {
+					// static libs and object files, absolute full path relative to the file in which the lib was imported from
 					lib_str = gb_string_append_fmt(lib_str, " -l:\"%.*s\" ", LIT(lib));
 				} else if (string_ends_with(lib, str_lit(".so"))) {
 					// dynamic lib, relative path to executable
@@ -418,7 +418,7 @@ i32 linker_stage(lbGenerator *gen) {
 					// dynamic or static system lib, just link regularly searching system library paths
 					lib_str = gb_string_append_fmt(lib_str, " -l%.*s ", LIT(lib));
 				}
-			#endif
+			}
 		}
 
 		gbString object_files = gb_string_make(heap_allocator(), "");
@@ -456,14 +456,15 @@ i32 linker_stage(lbGenerator *gen) {
 			// line arguments prepared previously are incompatible with ld.
 			//
 			// Shared libraries are .dylib on MacOS and .so on Linux.
-			#if defined(GB_SYSTEM_OSX)
+			if (build_context.metrics.os == TargetOs_darwin) {
 				output_ext = STR_LIT(".dylib");
-			#else
+			} else {
 				output_ext = STR_LIT(".so");
-			#endif
+			}
 			link_settings = gb_string_appendc(link_settings, "-Wl,-init,'_odin_entry_point' ");
 			link_settings = gb_string_appendc(link_settings, "-Wl,-fini,'_odin_exit_point' ");
-		} else {
+		} else if (build_context.metrics.os != TargetOs_openbsd) {
+			// OpenBSD defaults to PIE executable. do not pass -no-pie for it.
 			link_settings = gb_string_appendc(link_settings, "-no-pie ");
 		}
 		if (build_context.out_filepath.len > 0) {
@@ -474,34 +475,39 @@ i32 linker_stage(lbGenerator *gen) {
 			}
 		}
 
-		result = system_exec_command_line_app("ld-link",
-			"clang -Wno-unused-command-line-argument %s -o \"%.*s%.*s\" %s "
-			" %s "
-			" %.*s "
-			" %.*s "
-			" %s "
-			#if defined(GB_SYSTEM_OSX)
-				// This sets a requirement of Mountain Lion and up, but the compiler doesn't work without this limit.
-				// NOTE: If you change this (although this minimum is as low as you can go with Odin working)
-				//       make sure to also change the 'mtriple' param passed to 'opt'
-				#if defined(GB_CPU_ARM)
-				" -mmacosx-version-min=12.0.0 "
-				#else
-				" -mmacosx-version-min=10.8.0 "
-				#endif
-				// This points the linker to where the entry point is
-				" -e _main "
-			#endif
-			, object_files, LIT(output_base), LIT(output_ext),
-			#if defined(GB_SYSTEM_OSX)
-			  "-lSystem -lm -Wl,-syslibroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -L/usr/local/lib",
-			#else
-			  "-lc -lm",
-			#endif
-			lib_str,
-			LIT(build_context.link_flags),
-			LIT(build_context.extra_linker_flags),
-			link_settings);
+		gbString platform_lib_str = gb_string_make(heap_allocator(), "");
+		defer (gb_string_free(platform_lib_str));
+		if (build_context.metrics.os == TargetOs_darwin) {
+			platform_lib_str = gb_string_appendc(platform_lib_str, "-lSystem -lm -Wl,-syslibroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -L/usr/local/lib");
+		} else {
+			platform_lib_str = gb_string_appendc(platform_lib_str, "-lc -lm");
+		}
+
+		if (build_context.metrics.os == TargetOs_darwin) {
+			// This sets a requirement of Mountain Lion and up, but the compiler doesn't work without this limit.
+			// NOTE: If you change this (although this minimum is as low as you can go with Odin working)
+			//       make sure to also change the 'mtriple' param passed to 'opt'
+			if (build_context.metrics.arch == TargetArch_arm64) {
+				link_settings = gb_string_appendc(link_settings, " -mmacosx-version-min=12.0.0 ");
+			} else {
+				link_settings = gb_string_appendc(link_settings, " -mmacosx-version-min=10.8.0 ");
+			}
+			// This points the linker to where the entry point is
+			link_settings = gb_string_appendc(link_settings, " -e _main ");
+		}
+
+		gbString link_command_line = gb_string_make(heap_allocator(), "clang -Wno-unused-command-line-argument ");
+		defer (gb_string_free(link_command_line));
+
+		link_command_line = gb_string_appendc(link_command_line, object_files);
+		link_command_line = gb_string_append_fmt(link_command_line, " -o \"%.*s%.*s\" ", LIT(output_base), LIT(output_ext));
+		link_command_line = gb_string_append_fmt(link_command_line, " %s ", platform_lib_str);
+		link_command_line = gb_string_append_fmt(link_command_line, " %s ", lib_str);
+		link_command_line = gb_string_append_fmt(link_command_line, " %.*s ", LIT(build_context.link_flags));
+		link_command_line = gb_string_append_fmt(link_command_line, " %.*s ", LIT(build_context.extra_linker_flags));
+		link_command_line = gb_string_append_fmt(link_command_line, " %s ", link_settings);
+
+		result = system_exec_command_line_app("ld-link", link_command_line);
 
 		if (result) {
 			return result;
@@ -572,14 +578,16 @@ void usage(String argv0) {
 	print_usage_line(0, "Usage:");
 	print_usage_line(1, "%.*s command [arguments]", LIT(argv0));
 	print_usage_line(0, "Commands:");
-	print_usage_line(1, "build     compile .odin file, or directory of .odin files, as an executable.");
-	print_usage_line(1, "          one must contain the program's entry point, all must be in the same package.");
-	print_usage_line(1, "run       same as 'build', but also then runs the newly compiled executable.");
-	print_usage_line(1, "check     parse and type check .odin file");
-	print_usage_line(1, "query     parse, type check, and output a .json file containing information about the program");
-	print_usage_line(1, "doc       generate documentation .odin file, or directory of .odin files");
-	print_usage_line(1, "version   print version");
-	print_usage_line(1, "report    print information useful to reporting a bug");
+	print_usage_line(1, "build             compile .odin file, or directory of .odin files, as an executable.");
+	print_usage_line(1, "                  one must contain the program's entry point, all must be in the same package.");
+	print_usage_line(1, "run               same as 'build', but also then runs the newly compiled executable.");
+	print_usage_line(1, "check             parse, and type check an .odin file, or directory of .odin files");
+	print_usage_line(1, "query             parse, type check, and output a .json file containing information about the program");
+	print_usage_line(1, "strip-semicolon   parse, type check, and remove unneeded semicolons from the entire program");
+	print_usage_line(1, "test              build ands runs procedures with the attribute @(test) in the initial package");
+	print_usage_line(1, "doc               generate documentation .odin file, or directory of .odin files");
+	print_usage_line(1, "version           print version");
+	print_usage_line(1, "report            print information useful to reporting a bug");
 	print_usage_line(0, "");
 	print_usage_line(0, "For further details on a command, use -help after the command name");
 	print_usage_line(1, "e.g. odin build -help");
@@ -2577,7 +2585,7 @@ int main(int arg_count, char const **arg_ptr) {
 	// NOTE(bill): add 'shared' directory if it is not already set
 	if (!find_library_collection_path(str_lit("shared"), nullptr)) {
 		add_library_collection(str_lit("shared"),
-							   get_fullpath_relative(heap_allocator(), odin_root_dir(), str_lit("shared")));
+			get_fullpath_relative(heap_allocator(), odin_root_dir(), str_lit("shared")));
 	}
 
 
diff --git a/src/parser.cpp b/src/parser.cpp
index bd0e55b7f..94a585f35 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -57,6 +57,9 @@ isize ast_node_size(AstKind kind) {
 	return align_formula_isize(gb_size_of(AstCommonStuff) + ast_variant_sizes[kind], gb_align_of(void *));
 
 }
+
+gb_global std::atomic<isize> global_total_node_memory_allocated;
+
 // NOTE(bill): And this below is why is I/we need a new language! Discriminated unions are a pain in C/C++
 Ast *alloc_ast_node(AstFile *f, AstKind kind) {
 	gbAllocator a = ast_allocator(f);
@@ -66,6 +69,9 @@ Ast *alloc_ast_node(AstFile *f, AstKind kind) {
 	Ast *node = cast(Ast *)gb_alloc(a, size);
 	node->kind = kind;
 	node->file_id = f ? f->id : 0;
+
+	global_total_node_memory_allocated += size;
+
 	return node;
 }
 
@@ -1532,7 +1538,7 @@ void fix_advance_to_next_stmt(AstFile *f) {
 Token expect_closing(AstFile *f, TokenKind kind, String context) {
 	if (f->curr_token.kind != kind &&
 	    f->curr_token.kind == Token_Semicolon &&
-	    f->curr_token.string == "\n") {
+	    (f->curr_token.string == "\n" || f->curr_token.kind == Token_EOF)) {
 		Token tok = f->prev_token;
 		tok.pos.column += cast(i32)tok.string.len;
 		syntax_error(tok, "Missing ',' before newline in %.*s", LIT(context));
@@ -1554,6 +1560,7 @@ void assign_removal_flag_to_semicolon(AstFile *f) {
 			switch (curr_token->kind) {
 			case Token_CloseBrace:
 			case Token_CloseParen:
+			case Token_EOF:
 				ok = true;
 				break;
 			}
@@ -3009,64 +3016,62 @@ i32 token_precedence(AstFile *f, TokenKind t) {
 
 Ast *parse_binary_expr(AstFile *f, bool lhs, i32 prec_in) {
 	Ast *expr = parse_unary_expr(f, lhs);
-	for (i32 prec = token_precedence(f, f->curr_token.kind); prec >= prec_in; prec--) {
-		for (;;) {
-			Token op = f->curr_token;
-			i32 op_prec = token_precedence(f, op.kind);
-			if (op_prec != prec) {
-				// NOTE(bill): This will also catch operators that are not valid "binary" operators
-				break;
+	for (;;) {
+		Token op = f->curr_token;
+		i32 op_prec = token_precedence(f, op.kind);
+		if (op_prec < prec_in) {
+			// NOTE(bill): This will also catch operators that are not valid "binary" operators
+			break;
+		}
+		Token prev = f->prev_token;
+		switch (op.kind) {
+		case Token_if:
+		case Token_when:
+			if (prev.pos.line < op.pos.line) {
+				// NOTE(bill): Check to see if the `if` or `when` is on the same line of the `lhs` condition
+				goto loop_end;
 			}
-			Token prev = f->prev_token;
+			break;
+		}
+		expect_operator(f); // NOTE(bill): error checks too
+
+		if (op.kind == Token_Question) {
+			Ast *cond = expr;
+			// Token_Question
+			Ast *x = parse_expr(f, lhs);
+			Token token_c = expect_token(f, Token_Colon);
+			Ast *y = parse_expr(f, lhs);
+			expr = ast_ternary_if_expr(f, x, cond, y);
+		} else if (op.kind == Token_if || op.kind == Token_when) {
+			Ast *x = expr;
+			Ast *cond = parse_expr(f, lhs);
+			Token tok_else = expect_token(f, Token_else);
+			Ast *y = parse_expr(f, lhs);
+
 			switch (op.kind) {
 			case Token_if:
+				expr = ast_ternary_if_expr(f, x, cond, y);
+				break;
 			case Token_when:
-				if (prev.pos.line < op.pos.line) {
-					// NOTE(bill): Check to see if the `if` or `when` is on the same line of the `lhs` condition
-					goto loop_end;
-				}
+				expr = ast_ternary_when_expr(f, x, cond, y);
 				break;
 			}
-			expect_operator(f); // NOTE(bill): error checks too
-
-			if (op.kind == Token_Question) {
-				Ast *cond = expr;
-				// Token_Question
-				Ast *x = parse_expr(f, lhs);
-				Token token_c = expect_token(f, Token_Colon);
-				Ast *y = parse_expr(f, lhs);
-				expr = ast_ternary_if_expr(f, x, cond, y);
-			} else if (op.kind == Token_if || op.kind == Token_when) {
-				Ast *x = expr;
-				Ast *cond = parse_expr(f, lhs);
-				Token tok_else = expect_token(f, Token_else);
-				Ast *y = parse_expr(f, lhs);
-				
-				switch (op.kind) {
-				case Token_if:
-					expr = ast_ternary_if_expr(f, x, cond, y);
-					break;
-				case Token_when:
-					expr = ast_ternary_when_expr(f, x, cond, y);
-					break;
-				}
+		} else {
+			Ast *right = parse_binary_expr(f, false, op_prec+1);
+			if (right == nullptr) {
+				syntax_error(op, "Expected expression on the right-hand side of the binary operator '%.*s'", LIT(op.string));
+			}
+			if (op.kind == Token_or_else) {
+				// NOTE(bill): easier to handle its logic different with its own AST kind
+				expr = ast_or_else_expr(f, expr, op, right);
 			} else {
-				Ast *right = parse_binary_expr(f, false, prec+1);
-				if (right == nullptr) {
-					syntax_error(op, "Expected expression on the right-hand side of the binary operator '%.*s'", LIT(op.string));
-				}
-				if (op.kind == Token_or_else) {
-					// NOTE(bill): easier to handle its logic different with its own AST kind
-					expr = ast_or_else_expr(f, expr, op, right);	
-				} else {
-					expr = ast_binary_expr(f, op, expr, right);
-				}
+				expr = ast_binary_expr(f, op, expr, right);
 			}
-
-			lhs = false;
 		}
-		loop_end:;
+
+		lhs = false;
 	}
+	loop_end:;
 	return expr;
 }
 
@@ -3510,12 +3515,13 @@ enum FieldPrefixKind : i32 {
 	FieldPrefix_Unknown = -1,
 	FieldPrefix_Invalid = 0,
 
-	FieldPrefix_using,
+	FieldPrefix_using, // implies #subtype
 	FieldPrefix_const,
 	FieldPrefix_no_alias,
 	FieldPrefix_c_vararg,
 	FieldPrefix_auto_cast,
 	FieldPrefix_any_int,
+	FieldPrefix_subtype, // does not imply `using` semantics
 };
 
 struct ParseFieldPrefixMapping {
@@ -3532,6 +3538,7 @@ gb_global ParseFieldPrefixMapping parse_field_prefix_mappings[] = {
 	{str_lit("c_vararg"),   Token_Hash,      FieldPrefix_c_vararg,  FieldFlag_c_vararg},
 	{str_lit("const"),      Token_Hash,      FieldPrefix_const,     FieldFlag_const},
 	{str_lit("any_int"),    Token_Hash,      FieldPrefix_any_int,   FieldFlag_any_int},
+	{str_lit("subtype"),    Token_Hash,      FieldPrefix_subtype,   FieldFlag_subtype},
 };
 
 
@@ -4849,12 +4856,6 @@ ParseFileError init_ast_file(AstFile *f, String fullpath, TokenPos *err_pos) {
 	f->prev_token = f->tokens[f->prev_token_index];
 	f->curr_token = f->tokens[f->curr_token_index];
 
-	isize const page_size = 4*1024;
-	isize block_size = 2*f->tokens.count*gb_size_of(Ast);
-	block_size = ((block_size + page_size-1)/page_size) * page_size;
-	block_size = gb_clamp(block_size, page_size, DEFAULT_MINIMUM_BLOCK_SIZE);
-	f->arena.minimum_block_size = block_size;
-
 	array_init(&f->comments, heap_allocator(), 0, 0);
 	array_init(&f->imports,  heap_allocator(), 0, 0);
 
@@ -5719,6 +5720,22 @@ ParseFileError parse_packages(Parser *p, String init_filename) {
 			error_line("Expected either a directory or a .odin file, got '%.*s'\n", LIT(init_filename));
 			return ParseFile_WrongExtension;
 		}
+	} else if (init_fullpath.len != 0) {
+		String path = init_fullpath;
+		if (path[path.len-1] == '/') {
+			path.len -= 1;
+		}
+		if ((build_context.command_kind & Command__does_build) &&
+		    build_context.build_mode == BuildMode_Executable) {
+			String short_path = filename_from_path(path);
+			char *cpath = alloc_cstring(heap_allocator(), short_path);
+			defer (gb_free(heap_allocator(), cpath));
+
+			if (gb_file_exists(cpath)) {
+			    	error_line("Please specify the executable name with -out:<string> as a directory exists with the same name in the current working directory");
+			    	return ParseFile_DirectoryAlreadyExists;
+			}
+		}
 	}
 	
 
diff --git a/src/parser.hpp b/src/parser.hpp
index 9e93f4b26..c33d1520b 100644
--- a/src/parser.hpp
+++ b/src/parser.hpp
@@ -46,6 +46,7 @@ enum ParseFileError {
 	ParseFile_InvalidToken,
 	ParseFile_GeneralError,
 	ParseFile_FileTooLarge,
+	ParseFile_DirectoryAlreadyExists,
 
 	ParseFile_Count,
 };
@@ -97,8 +98,6 @@ struct AstFile {
 	AstPackage * pkg;
 	Scope *      scope;
 
-	Arena  arena;
-
 	Ast *        pkg_decl;
 	String       fullpath;
 	Tokenizer    tokenizer;
@@ -300,6 +299,7 @@ enum FieldFlag : u32 {
 	FieldFlag_auto_cast = 1<<4,
 	FieldFlag_const     = 1<<5,
 	FieldFlag_any_int   = 1<<6,
+	FieldFlag_subtype   = 1<<7,
 
 	// Internal use by the parser only
 	FieldFlag_Tags      = 1<<10,
@@ -307,7 +307,7 @@ enum FieldFlag : u32 {
 
 	// Parameter List Restrictions
 	FieldFlag_Signature = FieldFlag_ellipsis|FieldFlag_using|FieldFlag_no_alias|FieldFlag_c_vararg|FieldFlag_auto_cast|FieldFlag_const|FieldFlag_any_int,
-	FieldFlag_Struct    = FieldFlag_using|FieldFlag_Tags,
+	FieldFlag_Struct    = FieldFlag_using|FieldFlag_subtype|FieldFlag_Tags,
 };
 
 enum StmtAllowFlag {
@@ -800,10 +800,10 @@ gb_inline bool is_ast_when_stmt(Ast *node) {
 	return node->kind == Ast_WhenStmt;
 }
 
-gb_global gb_thread_local Arena global_ast_arena = {};
+gb_global gb_thread_local Arena global_thread_local_ast_arena = {};
 
 gbAllocator ast_allocator(AstFile *f) {
-	Arena *arena = f ? &f->arena : &global_ast_arena;
+	Arena *arena = &global_thread_local_ast_arena;
 	return arena_allocator(arena);
 }
 
diff --git a/src/threading.cpp b/src/threading.cpp
index 50d0dfed1..63e3415b2 100644
--- a/src/threading.cpp
+++ b/src/threading.cpp
@@ -486,7 +486,7 @@ void thread_set_name(Thread *t, char const *name) {
 #elif defined(GB_SYSTEM_OSX)
 	// TODO(bill): Test if this works
 	pthread_setname_np(name);
-#elif defined(GB_SYSTEM_FREEBSD)
+#elif defined(GB_SYSTEM_FREEBSD) || defined(GB_SYSTEM_OPENBSD)
 	pthread_set_name_np(t->posix_handle, name);
 #else
 	// TODO(bill): Test if this works
diff --git a/src/types.cpp b/src/types.cpp
index 78958146b..58ccdf5b9 100644
--- a/src/types.cpp
+++ b/src/types.cpp
@@ -703,7 +703,7 @@ struct TypePath;
 i64      type_size_of         (Type *t);
 i64      type_align_of        (Type *t);
 i64      type_offset_of       (Type *t, i32 index);
-gbString type_to_string       (Type *type);
+gbString type_to_string       (Type *type, bool shorthand=false);
 i64      type_size_of_internal(Type *t, TypePath *path);
 void     init_map_internal_types(Type *type);
 Type *   bit_set_to_int(Type *t);
@@ -2334,7 +2334,7 @@ String lookup_subtype_polymorphic_field(Type *dst, Type *src) {
 	GB_ASSERT(is_type_struct(src) || is_type_union(src));
 	for_array(i, src->Struct.fields) {
 		Entity *f = src->Struct.fields[i];
-		if (f->kind == Entity_Variable && f->flags & EntityFlag_Using) {
+		if (f->kind == Entity_Variable && f->flags & EntityFlags_IsSubtype) {
 			if (are_types_identical(dst, f->type)) {
 				return f->token.string;
 			}
@@ -2343,7 +2343,7 @@ String lookup_subtype_polymorphic_field(Type *dst, Type *src) {
 					return f->token.string;
 				}
 			}
-			if (is_type_struct(f->type)) {
+			if ((f->flags & EntityFlag_Using) != 0 && is_type_struct(f->type)) {
 				String name = lookup_subtype_polymorphic_field(dst, f->type);
 				if (name.len > 0) {
 					return name;
@@ -2489,9 +2489,9 @@ bool are_types_identical_internal(Type *x, Type *y, bool check_tuple_names) {
 					if (xf->token.string != yf->token.string) {
 						return false;
 					}
-					bool xf_is_using = (xf->flags&EntityFlag_Using) != 0;
-					bool yf_is_using = (yf->flags&EntityFlag_Using) != 0;
-					if (xf_is_using ^ yf_is_using) {
+					u64 xf_flags = (xf->flags&EntityFlags_IsSubtype);
+					u64 yf_flags = (yf->flags&EntityFlags_IsSubtype);
+					if (xf_flags != yf_flags) {
 						return false;
 					}
 				}
@@ -2623,6 +2623,17 @@ i64 union_tag_size(Type *u) {
 
 	// TODO(bill): Is this an okay approach?
 	i64 max_align = 1;
+
+	if (u->Union.variants.count < 1ull<<8) {
+		max_align = 1;
+	} else if (u->Union.variants.count < 1ull<<16) {
+		max_align = 2;
+	} else if (u->Union.variants.count < 1ull<<32) {
+		max_align = 4;
+	} else {
+		GB_PANIC("how many variants do you have?!");
+	}
+
 	for_array(i, u->Union.variants) {
 		Type *variant_type = u->Union.variants[i];
 		i64 align = type_align_of(variant_type);
@@ -3813,7 +3824,7 @@ isize check_is_assignable_to_using_subtype(Type *src, Type *dst, isize level = 0
 
 	for_array(i, src->Struct.fields) {
 		Entity *f = src->Struct.fields[i];
-		if (f->kind != Entity_Variable || (f->flags&EntityFlag_Using) == 0) {
+		if (f->kind != Entity_Variable || (f->flags&EntityFlags_IsSubtype) == 0) {
 			continue;
 		}
 
@@ -3925,7 +3936,7 @@ Type *alloc_type_proc_from_types(Type **param_types, unsigned param_count, Type
 
 
 
-gbString write_type_to_string(gbString str, Type *type) {
+gbString write_type_to_string(gbString str, Type *type, bool shorthand=false) {
 	if (type == nullptr) {
 		return gb_string_appendc(str, "<no type>");
 	}
@@ -4040,15 +4051,21 @@ gbString write_type_to_string(gbString str, Type *type) {
 		if (type->Struct.is_raw_union) str = gb_string_appendc(str, " #raw_union");
 		if (type->Struct.custom_align != 0) str = gb_string_append_fmt(str, " #align %d", cast(int)type->Struct.custom_align);
 		str = gb_string_appendc(str, " {");
-		for_array(i, type->Struct.fields) {
-			Entity *f = type->Struct.fields[i];
-			GB_ASSERT(f->kind == Entity_Variable);
-			if (i > 0) {
-				str = gb_string_appendc(str, ", ");
+
+
+		if (shorthand && type->Struct.fields.count > 16) {
+			str = gb_string_append_fmt(str, "%lld fields...", cast(long long)type->Struct.fields.count);
+		} else {
+			for_array(i, type->Struct.fields) {
+				Entity *f = type->Struct.fields[i];
+				GB_ASSERT(f->kind == Entity_Variable);
+				if (i > 0) {
+					str = gb_string_appendc(str, ", ");
+				}
+				str = gb_string_append_length(str, f->token.string.text, f->token.string.len);
+				str = gb_string_appendc(str, ": ");
+				str = write_type_to_string(str, f->type);
 			}
-			str = gb_string_append_length(str, f->token.string.text, f->token.string.len);
-			str = gb_string_appendc(str, ": ");
-			str = write_type_to_string(str, f->type);
 		}
 		str = gb_string_append_rune(str, '}');
 	} break;
@@ -4223,13 +4240,16 @@ gbString write_type_to_string(gbString str, Type *type) {
 }
 
 
-gbString type_to_string(Type *type, gbAllocator allocator) {
-	return write_type_to_string(gb_string_make(allocator, ""), type);
+gbString type_to_string(Type *type, gbAllocator allocator, bool shorthand=false) {
+	return write_type_to_string(gb_string_make(allocator, ""), type, shorthand);
 }
-gbString type_to_string(Type *type) {
-	return write_type_to_string(gb_string_make(heap_allocator(), ""), type);
+gbString type_to_string(Type *type, bool shorthand) {
+	return write_type_to_string(gb_string_make(heap_allocator(), ""), type, shorthand);
 }
 
+gbString type_to_string_shorthand(Type *type) {
+	return type_to_string(type, true);
+}