diff --git a/core/os/os_darwin.odin b/core/os/os_darwin.odin
new file mode 100644
index 000000000..7b183b3aa
--- /dev/null
+++ b/core/os/os_darwin.odin
@@ -0,0 +1,295 @@
+package os
+
+foreign import dl   "system:dl"
+foreign import libc "system:c"
+
+import "core:runtime"
+import "core:strings"
+
+OS :: "darwin";
+
+Handle    :: distinct i32;
+File_Time :: distinct u64;
+Errno     :: distinct int;
+
+INVALID_HANDLE :: ~Handle(0);
+
+O_RDONLY   :: 0x00000;
+O_WRONLY   :: 0x00001;
+O_RDWR     :: 0x00002;
+O_CREATE   :: 0x00040;
+O_EXCL     :: 0x00080;
+O_NOCTTY   :: 0x00100;
+O_TRUNC    :: 0x00200;
+O_NONBLOCK :: 0x00800;
+O_APPEND   :: 0x00400;
+O_SYNC     :: 0x01000;
+O_ASYNC    :: 0x02000;
+O_CLOEXEC  :: 0x80000;
+
+
+SEEK_SET   :: 0;
+SEEK_CUR   :: 1;
+SEEK_END   :: 2;
+SEEK_DATA  :: 3;
+SEEK_HOLE  :: 4;
+SEEK_MAX   :: SEEK_HOLE;
+
+
+
+// NOTE(zangent): These are OS specific!
+// Do not mix these up!
+RTLD_LAZY     :: 0x1;
+RTLD_NOW      :: 0x2;
+RTLD_LOCAL    :: 0x4;
+RTLD_GLOBAL   :: 0x8;
+RTLD_NODELETE :: 0x80;
+RTLD_NOLOAD   :: 0x10;
+RTLD_FIRST    :: 0x100;
+
+
+// "Argv" arguments converted to Odin strings
+args := _alloc_command_line_arguments();
+
+_File_Time :: struct {
+	seconds: i64,
+	nanoseconds: i64,
+}
+
+Stat :: struct {
+	device_id:     i32, // ID of device containing file
+	mode:          u16, // Mode of the file
+	nlink:         u16, // Number of hard links
+	serial:        u64, // File serial number
+	uid:           u32, // User ID of the file's owner
+	gid:           u32, // Group ID of the file's group
+	rdev:          i32, // Device ID, if device
+
+	last_access:   File_Time, // Time of last access
+	modified:      File_Time, // Time of last modification
+	status_change: File_Time, // Time of last status change
+	created:       File_Time, // Time of creation
+
+	size:          i64,  // Size of the file, in bytes
+	blocks:        i64,  // Number of blocks allocated for the file
+	block_size:    i32,  // Optimal blocksize for I/O
+	flags:         u32,  // User-defined flags for the file
+	gen_num:       u32,  // File generation number ..?
+	_spare:        i32,  // RESERVED
+	_reserve1,
+	_reserve2:     i64,  // RESERVED
+};
+
+// File type
+S_IFMT   :: 0o170000; // Type of file mask
+S_IFIFO  :: 0o010000; // Named pipe (fifo)
+S_IFCHR  :: 0o020000; // Character special
+S_IFDIR  :: 0o040000; // Directory
+S_IFBLK  :: 0o060000; // Block special
+S_IFREG  :: 0o100000; // Regular
+S_IFLNK  :: 0o120000; // Symbolic link
+S_IFSOCK :: 0o140000; // Socket
+
+// File mode
+// Read, write, execute/search by owner
+S_IRWXU :: 0o0700; // RWX mask for owner
+S_IRUSR :: 0o0400; // R for owner
+S_IWUSR :: 0o0200; // W for owner
+S_IXUSR :: 0o0100; // X for owner
+
+// Read, write, execute/search by group
+S_IRWXG :: 0o0070; // RWX mask for group
+S_IRGRP :: 0o0040; // R for group
+S_IWGRP :: 0o0020; // W for group
+S_IXGRP :: 0o0010; // X for group
+
+// Read, write, execute/search by others
+S_IRWXO :: 0o0007; // RWX mask for other
+S_IROTH :: 0o0004; // R for other
+S_IWOTH :: 0o0002; // W for other
+S_IXOTH :: 0o0001; // X for other
+
+S_ISUID :: 0o4000; // Set user id on execution
+S_ISGID :: 0o2000; // Set group id on execution
+S_ISVTX :: 0o1000; // Directory restrcted delete
+
+S_ISLNK  :: inline proc(m: u32) -> bool do return (m & S_IFMT) == S_IFLNK;
+S_ISREG  :: inline proc(m: u32) -> bool do return (m & S_IFMT) == S_IFREG;
+S_ISDIR  :: inline proc(m: u32) -> bool do return (m & S_IFMT) == S_IFDIR;
+S_ISCHR  :: inline proc(m: u32) -> bool do return (m & S_IFMT) == S_IFCHR;
+S_ISBLK  :: inline proc(m: u32) -> bool do return (m & S_IFMT) == S_IFBLK;
+S_ISFIFO :: inline proc(m: u32) -> bool do return (m & S_IFMT) == S_IFIFO;
+S_ISSOCK :: inline proc(m: u32) -> bool do return (m & S_IFMT) == S_IFSOCK;
+
+R_OK :: 4; // Test for read permission
+W_OK :: 2; // Test for write permission
+X_OK :: 1; // Test for execute permission
+F_OK :: 0; // Test for file existance
+
+foreign libc {
+	@(link_name="open")    _unix_open    :: proc(path: cstring, flags: int, #c_vararg mode: ..any) -> Handle ---;
+	@(link_name="close")   _unix_close   :: proc(handle: Handle) ---;
+	@(link_name="read")    _unix_read    :: proc(handle: Handle, buffer: rawptr, count: int) -> int ---;
+	@(link_name="write")   _unix_write   :: proc(handle: Handle, buffer: rawptr, count: int) -> int ---;
+	@(link_name="lseek")   _unix_lseek   :: proc(fs: Handle, offset: int, whence: int) -> int ---;
+	@(link_name="gettid")  _unix_gettid  :: proc() -> u64 ---;
+	@(link_name="stat")    _unix_stat    :: proc(path: cstring, stat: ^Stat) -> int ---;
+	@(link_name="access")  _unix_access  :: proc(path: cstring, mask: int) -> int ---;
+
+	@(link_name="malloc")  _unix_malloc  :: proc(size: int) -> rawptr ---;
+	@(link_name="calloc")  _unix_calloc  :: proc(num, size: int) -> rawptr ---;
+	@(link_name="free")    _unix_free    :: proc(ptr: rawptr) ---;
+	@(link_name="realloc") _unix_realloc :: proc(ptr: rawptr, size: int) -> rawptr ---;
+	@(link_name="getenv")  _unix_getenv  :: proc(cstring) -> cstring ---;
+
+	@(link_name="exit")    _unix_exit    :: proc(status: int) ---;
+}
+
+foreign dl {
+	@(link_name="dlopen")  _unix_dlopen  :: proc(filename: cstring, flags: int) -> rawptr ---;
+	@(link_name="dlsym")   _unix_dlsym   :: proc(handle: rawptr, symbol: cstring) -> rawptr ---;
+	@(link_name="dlclose") _unix_dlclose :: proc(handle: rawptr) -> int ---;
+	@(link_name="dlerror") _unix_dlerror :: proc() -> cstring ---;
+}
+
+open :: proc(path: string, flags: int = O_RDONLY, mode: int = 0) -> (Handle, Errno) {
+	cstr := strings.clone_to_cstring(path);
+	handle := _unix_open(cstr, flags, mode);
+	delete(cstr);
+	if handle == -1 {
+		return INVALID_HANDLE, 1;
+	}
+	return handle, 0;
+}
+
+close :: proc(fd: Handle) {
+	_unix_close(fd);
+}
+
+write :: proc(fd: Handle, data: []u8) -> (int, Errno) {
+	assert(fd != -1);
+
+	bytes_written := _unix_write(fd, &data[0], len(data));
+	if(bytes_written == -1) {
+		return 0, 1;
+	}
+	return bytes_written, 0;
+}
+
+read :: proc(fd: Handle, data: []u8) -> (int, Errno) {
+	assert(fd != -1);
+
+	bytes_read := _unix_read(fd, &data[0], len(data));
+	if bytes_read == -1 {
+		return 0, 1;
+	}
+	return bytes_read, 0;
+}
+
+seek :: proc(fd: Handle, offset: i64, whence: int) -> (i64, Errno) {
+	assert(fd != -1);
+
+	final_offset := i64(_unix_lseek(fd, int(offset), whence));
+	if final_offset == -1 {
+		return 0, 1;
+	}
+	return final_offset, 0;
+}
+
+file_size :: proc(fd: Handle) -> (i64, Errno) {
+	prev, _   := seek(fd, 0, SEEK_CUR);
+	size, err := seek(fd, 0, SEEK_END);
+	seek(fd, prev, SEEK_SET);
+	return i64(size), err;
+}
+
+
+
+// NOTE(bill): Uses startup to initialize it
+stdin:  Handle = 0; // get_std_handle(win32.STD_INPUT_HANDLE);
+stdout: Handle = 1; // get_std_handle(win32.STD_OUTPUT_HANDLE);
+stderr: Handle = 2; // get_std_handle(win32.STD_ERROR_HANDLE);
+
+/* TODO(zangent): Implement these!
+last_write_time :: proc(fd: Handle) -> File_Time {}
+last_write_time_by_name :: proc(name: string) -> File_Time {}
+*/
+
+is_path_separator :: proc(r: rune) -> bool {
+	return r == '/';
+}
+
+stat :: inline proc(path: string) -> (Stat, bool) {
+	s: Stat;
+	cstr := strings.clone_to_cstring(path);
+	defer delete(cstr);
+	ret_int := _unix_stat(cstr, &s);
+	return s, ret_int==0;
+}
+
+access :: inline proc(path: string, mask: int) -> bool {
+	cstr := strings.clone_to_cstring(path);
+	defer delete(cstr);
+	return _unix_access(cstr, mask) == 0;
+}
+
+heap_alloc :: inline proc(size: int) -> rawptr {
+	assert(size > 0);
+	return _unix_calloc(1, size);
+}
+heap_resize :: inline proc(ptr: rawptr, new_size: int) -> rawptr {
+	return _unix_realloc(ptr, new_size);
+}
+heap_free :: inline proc(ptr: rawptr) {
+	_unix_free(ptr);
+}
+
+getenv :: proc(name: string) -> (string, bool) {
+	path_str := strings.clone_to_cstring(name);
+	defer delete(path_str);
+	cstr := _unix_getenv(path_str);
+	if cstr == nil {
+		return "", false;
+	}
+	return string(cstr), true;
+}
+
+exit :: inline proc(code: int) -> ! {
+	_unix_exit(code);
+}
+
+
+current_thread_id :: proc "contextless" () -> int {
+	// return int(_unix_gettid());
+	return 0;
+}
+
+dlopen :: inline proc(filename: string, flags: int) -> rawptr {
+	cstr := strings.clone_to_cstring(filename);
+	defer delete(cstr);
+	handle := _unix_dlopen(cstr, flags);
+	return handle;
+}
+dlsym :: inline proc(handle: rawptr, symbol: string) -> rawptr {
+	assert(handle != nil);
+	cstr := strings.clone_to_cstring(symbol);
+	defer delete(cstr);
+	proc_handle := _unix_dlsym(handle, cstr);
+	return proc_handle;
+}
+dlclose :: inline proc(handle: rawptr) -> bool {
+	assert(handle != nil);
+	return _unix_dlclose(handle) == 0;
+}
+dlerror :: proc() -> string {
+	return string(_unix_dlerror());
+}
+
+
+_alloc_command_line_arguments :: proc() -> []string {
+	res := make([]string, len(runtime.args__));
+	for arg, i in runtime.args__ {
+		res[i] = string(arg);
+	}
+	return res;
+}
diff --git a/core/time/time_osx.odin b/core/time/time_darwin.odin
similarity index 100%
rename from core/time/time_osx.odin
rename to core/time/time_darwin.odin
diff --git a/src/build_settings.cpp b/src/build_settings.cpp
index 956ffe1ed..b4abf41a7 100644
--- a/src/build_settings.cpp
+++ b/src/build_settings.cpp
@@ -2,7 +2,7 @@ enum TargetOsKind {
 	TargetOs_Invalid,
 
 	TargetOs_windows,
-	TargetOs_osx,
+	TargetOs_darwin,
 	TargetOs_linux,
 	TargetOs_essence,
 
@@ -30,7 +30,7 @@ enum TargetEndianKind {
 String target_os_names[TargetOs_COUNT] = {
 	str_lit(""),
 	str_lit("windows"),
-	str_lit("osx"),
+	str_lit("darwin"),
 	str_lit("linux"),
 	str_lit("essence"),
 };
@@ -166,8 +166,8 @@ gb_global TargetMetrics target_linux_amd64 = {
 	str_lit("x86_64-pc-linux-gnu"),
 };
 
-gb_global TargetMetrics target_osx_amd64 = {
-	TargetOs_osx,
+gb_global TargetMetrics target_darwin_amd64 = {
+	TargetOs_darwin,
 	TargetArch_amd64,
 	8,
 	16,
@@ -189,7 +189,7 @@ struct NamedTargetMetrics {
 
 gb_global NamedTargetMetrics named_targets[] = {
 	{ str_lit("essence_amd64"), &target_essence_amd64 },
-	{ str_lit("macos_amd64"),   &target_osx_amd64 },
+	{ str_lit("darwin_amd64"),   &target_darwin_amd64 },
 	{ str_lit("linux_386"),     &target_linux_386 },
 	{ str_lit("linux_amd64"),   &target_linux_amd64 },
 	{ str_lit("windows_386"),   &target_windows_386 },
@@ -566,7 +566,7 @@ void init_build_context(TargetMetrics *cross_target) {
 		#if defined(GB_SYSTEM_WINDOWS)
 			metrics = target_windows_amd64;
 		#elif defined(GB_SYSTEM_OSX)
-			metrics = target_osx_amd64;
+			metrics = target_darwin_amd64;
 		#else
 			metrics = target_linux_amd64;
 		#endif
@@ -618,7 +618,7 @@ void init_build_context(TargetMetrics *cross_target) {
 		case TargetOs_windows:
 			bc->link_flags = str_lit("/machine:x64 ");
 			break;
-		case TargetOs_osx:
+		case TargetOs_darwin:
 			break;
 		case TargetOs_linux:
 			bc->link_flags = str_lit("-arch x86-64 ");
@@ -631,7 +631,7 @@ void init_build_context(TargetMetrics *cross_target) {
 		case TargetOs_windows:
 			bc->link_flags = str_lit("/machine:x86 ");
 			break;
-		case TargetOs_osx:
+		case TargetOs_darwin:
 			gb_printf_err("Unsupported architecture\n");
 			gb_exit(1);
 			break;
diff --git a/src/check_type.cpp b/src/check_type.cpp
index 465c11731..9f5ed0ed3 100644
--- a/src/check_type.cpp
+++ b/src/check_type.cpp
@@ -1915,7 +1915,7 @@ Type *type_to_abi_compat_param_type(gbAllocator a, Type *original_type, ProcCall
 		}
 		}
 	} else if (build_context.ODIN_OS == "linux" ||
-	           build_context.ODIN_OS == "osx") {
+	           build_context.ODIN_OS == "darwin") {
 		Type *bt = core_type(original_type);
 		switch (bt->kind) {
 		// Okay to pass by value (usually)
diff --git a/src/ir_print.cpp b/src/ir_print.cpp
index 9414a2338..db9eb1bfb 100644
--- a/src/ir_print.cpp
+++ b/src/ir_print.cpp
@@ -1165,7 +1165,8 @@ void ir_print_calling_convention(irFileBuffer *f, irModule *m, ProcCallingConven
 	switch (cc) {
 	case ProcCC_Odin:        ir_write_str_lit(f, "");       break;
 	case ProcCC_Contextless: ir_write_str_lit(f, "");       break;
-	case ProcCC_CDecl:       ir_write_str_lit(f, "ccc ");   break;
+	// case ProcCC_CDecl:       ir_write_str_lit(f, "ccc ");   break;
+	case ProcCC_CDecl:       ir_write_str_lit(f, "");   break;
 	case ProcCC_StdCall:     ir_write_str_lit(f, "cc 64 "); break;
 	case ProcCC_FastCall:    ir_write_str_lit(f, "cc 65 "); break;
 	case ProcCC_None:        ir_write_str_lit(f, "");       break;
@@ -1175,8 +1176,8 @@ void ir_print_calling_convention(irFileBuffer *f, irModule *m, ProcCallingConven
 
 void ir_print_context_parameter_prefix(irFileBuffer *f, irModule *m) {
 	ir_print_type(f, m, t_context_ptr);
-	ir_write_str_lit(f, " noalias nonnull nocapture inreg ");
-	// ir_write_str_lit(f, " noalias nonnull nocapture ");
+	// ir_write_str_lit(f, " noalias nonnull nocapture inreg ");
+	ir_write_str_lit(f, " noalias nonnull nocapture ");
 }
 
 void ir_print_instr(irFileBuffer *f, irModule *m, irValue *value) {
@@ -1227,6 +1228,7 @@ void ir_print_instr(irFileBuffer *f, irModule *m, irValue *value) {
 		ir_write_str_lit(f, ", ");
 		ir_print_type(f, m, type);
 		ir_fprintf(f, "* %%%d, align 1", instr->ZeroInit.address->index);
+		// ir_fprintf(f, "* %%%d", instr->ZeroInit.address->index);
 		break;
 	}
 
@@ -2244,9 +2246,11 @@ void print_llvm_ir(irGen *ir) {
 	defer (ir_file_buffer_destroy(f));
 
 	i32 word_bits = cast(i32)(8*build_context.word_size);
-	if (build_context.ODIN_OS == "osx" || build_context.ODIN_OS == "macos") {
+	if (build_context.ODIN_OS == "darwin") {
 		GB_ASSERT(word_bits == 64);
-		ir_write_str_lit(f, "target triple = \"x86_64-apple-macosx10.8\"\n\n");
+		ir_write_str_lit(f, "target datalayout = \"e-m:o-i64:64-f80:128-n8:16:32:64-S128\"\n");
+		ir_write_str_lit(f, "target triple = \"x86_64-apple-macosx10.8\"\n");
+		ir_write_str_lit(f, "\n");
 	} else if (build_context.ODIN_OS == "windows") {
 		ir_fprintf(f, "target triple = \"x86%s-pc-windows-msvc\"\n\n", word_bits == 64 ? "_64" : "");
 		if (word_bits == 64 && build_context.metrics.arch == TargetArch_amd64) {