merge from upstream and convert to ^File types

24 files changed, 1480 insertions, 860 deletions

diff --git a/src/big_int.cpp b/src/big_int.cpp
index 20f940e8e..5509545ca 100644
--- a/src/big_int.cpp
+++ b/src/big_int.cpp
@@ -40,7 +40,7 @@ typedef mp_int BigInt;
 void big_int_from_u64(BigInt *dst, u64 x);
 void big_int_from_i64(BigInt *dst, i64 x);
 void big_int_init    (BigInt *dst, BigInt const *src);
-void big_int_from_string(BigInt *dst, String const &s);
+void big_int_from_string(BigInt *dst, String const &s, bool *success);
 
 void big_int_dealloc(BigInt *dst) {
 	mp_clear(dst);
@@ -84,7 +84,7 @@ void big_int_quo_eq(BigInt *dst, BigInt const *x);
 void big_int_rem_eq(BigInt *dst, BigInt const *x);
 
 bool big_int_is_neg(BigInt const *x);
-
+void big_int_neg(BigInt *dst, BigInt const *x);
 
 void big_int_add_eq(BigInt *dst, BigInt const *x) {
 	BigInt res = {};
@@ -169,7 +169,11 @@ BigInt big_int_make_i64(i64 x) {
 }
 
 
-void big_int_from_string(BigInt *dst, String const &s) {
+void big_int_from_string(BigInt *dst, String const &s, bool *success) {
+	*success = true;
+
+	bool is_negative = false;
+
 	u64 base = 10;
 	bool has_prefix = false;
 	if (s.len > 2 && s[0] == '0') {
@@ -197,11 +201,26 @@ void big_int_from_string(BigInt *dst, String const &s) {
 	isize i = 0;
 	for (; i < len; i++) {
 		Rune r = cast(Rune)text[i];
+
+		if (r == '-') {
+			if (is_negative) {
+				// NOTE(Jeroen): Can't have a doubly negative number.
+				*success = false;
+				return;
+			}
+			is_negative = true;
+			continue;
+		}
+
 		if (r == '_') {
 			continue;
 		}
 		u64 v = u64_digit_value(r);
 		if (v >= base) {
+			// NOTE(Jeroen): Can still be a valid integer if the next character is an `e` or `E`.
+			if (r != 'e' && r != 'E') {
+				*success = false;
+			}
 			break;
 		}
 		BigInt val = big_int_make_u64(v);
@@ -225,6 +244,7 @@ void big_int_from_string(BigInt *dst, String const &s) {
 			if (gb_char_is_digit(r)) {
 				v = u64_digit_value(r);
 			} else {
+				*success = false;
 				break;
 			}
 			exp *= 10;
@@ -234,6 +254,10 @@ void big_int_from_string(BigInt *dst, String const &s) {
 			big_int_mul_eq(dst, &b);
 		}
 	}
+
+	if (is_negative) {
+		big_int_neg(dst, dst);
+	}
 }
 
 
diff --git a/src/build_settings.cpp b/src/build_settings.cpp
index 2f3eb03a5..e596e54e5 100644
--- a/src/build_settings.cpp
+++ b/src/build_settings.cpp
@@ -3,7 +3,6 @@
 #include <sys/sysctl.h>
 #endif
 
-
 // #if defined(GB_SYSTEM_WINDOWS)
 // #define DEFAULT_TO_THREADED_CHECKER
 // #endif
@@ -31,6 +30,7 @@ enum TargetArchKind : u16 {
 
 	TargetArch_amd64,
 	TargetArch_i386,
+	TargetArch_arm32,
 	TargetArch_arm64,
 	TargetArch_wasm32,
 	TargetArch_wasm64,
@@ -76,6 +76,7 @@ String target_arch_names[TargetArch_COUNT] = {
 	str_lit(""),
 	str_lit("amd64"),
 	str_lit("i386"),
+	str_lit("arm32"),
 	str_lit("arm64"),
 	str_lit("wasm32"),
 	str_lit("wasm64"),
@@ -99,6 +100,7 @@ TargetEndianKind target_endians[TargetArch_COUNT] = {
 	TargetEndian_Little,
 	TargetEndian_Little,
 	TargetEndian_Little,
+	TargetEndian_Little,
 };
 
 #ifndef ODIN_VERSION_RAW
@@ -198,6 +200,22 @@ enum RelocMode : u8 {
 	RelocMode_DynamicNoPIC,
 };
 
+enum BuildPath : u8 {
+	BuildPath_Main_Package,     // Input  Path to the package directory (or file) we're building.
+	BuildPath_RC,               // Input  Path for .rc  file, can be set with `-resource:`.
+	BuildPath_RES,              // Output Path for .res file, generated from previous.
+	BuildPath_Win_SDK_Root,     // windows_sdk_root
+	BuildPath_Win_SDK_UM_Lib,   // windows_sdk_um_library_path
+	BuildPath_Win_SDK_UCRT_Lib, // windows_sdk_ucrt_library_path
+	BuildPath_VS_EXE,           // vs_exe_path
+	BuildPath_VS_LIB,           // vs_library_path
+
+	BuildPath_Output,           // Output Path for .exe, .dll, .so, etc. Can be overridden with `-out:`.
+	BuildPath_PDB,              // Output Path for .pdb file, can be overridden with `-pdb-name:`.
+
+	BuildPathCOUNT,
+};
+
 // This stores the information for the specify architecture of this build
 struct BuildContext {
 	// Constants
@@ -226,9 +244,13 @@ struct BuildContext {
 
 	bool show_help;
 
+	Array<Path> build_paths;   // Contains `Path` objects to output filename, pdb, resource and intermediate files.
+	                           // BuildPath enum contains the indices of paths we know *before* the work starts.
+
 	String out_filepath;
 	String resource_filepath;
 	String pdb_filepath;
+
 	bool   has_resource;
 	String link_flags;
 	String extra_linker_flags;
@@ -300,8 +322,6 @@ struct BuildContext {
 
 };
 
-
-
 gb_global BuildContext build_context = {0};
 
 bool global_warnings_as_errors(void) {
@@ -350,7 +370,16 @@ gb_global TargetMetrics target_linux_arm64 = {
 	8,
 	16,
 	str_lit("aarch64-linux-elf"),
-	str_lit("e-m:e-i8:8:32-i16:32-i64:64-i128:128-n32:64-S128"),
+	str_lit("e-m:o-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"),
+};
+
+gb_global TargetMetrics target_linux_arm32 = {
+	TargetOs_linux,
+	TargetArch_arm32,
+	4,
+	8,
+	str_lit("arm-linux-gnu"),
+	str_lit("e-m:o-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"),
 };
 
 gb_global TargetMetrics target_darwin_amd64 = {
@@ -466,6 +495,7 @@ gb_global NamedTargetMetrics named_targets[] = {
 	{ str_lit("linux_i386"),          &target_linux_i386     },
 	{ str_lit("linux_amd64"),         &target_linux_amd64    },
 	{ str_lit("linux_arm64"),         &target_linux_arm64    },
+	{ str_lit("linux_arm32"),         &target_linux_arm32    },
 	{ str_lit("windows_i386"),        &target_windows_i386   },
 	{ str_lit("windows_amd64"),       &target_windows_amd64  },
 	{ str_lit("freebsd_i386"),        &target_freebsd_i386   },
@@ -605,28 +635,6 @@ bool allow_check_foreign_filepath(void) {
 // is_abs_path
 // has_subdir
 
-enum TargetFileValidity : u8 {
-	TargetFileValidity_Invalid,
-
-	TargetFileValidity_Writable_File,
-	TargetFileValidity_No_Write_Permission,
-	TargetFileValidity_Directory,
-
-	TargetTargetFileValidity_COUNT,
-};
-
-TargetFileValidity set_output_filename(void) {
-	// Assembles the output filename from build_context information.
-	// Returns `true`  if it doesn't exist or is a file.
-	// Returns `false` if a directory or write-protected file.
-
-
-
-
-	return TargetFileValidity_Writable_File;
-}
-
-
 String const WIN32_SEPARATOR_STRING = {cast(u8 *)"\\", 1};
 String const NIX_SEPARATOR_STRING   = {cast(u8 *)"/",  1};
 
@@ -973,7 +981,6 @@ char *token_pos_to_string(TokenPos const &pos) {
 	return s;
 }
 
-
 void init_build_context(TargetMetrics *cross_target) {
 	BuildContext *bc = &build_context;
 
@@ -1120,6 +1127,15 @@ void init_build_context(TargetMetrics *cross_target) {
 			bc->link_flags = str_lit("-arch x86 ");
 			break;
 		}
+	} else if (bc->metrics.arch == TargetArch_arm32) {
+		switch (bc->metrics.os) {
+		case TargetOs_linux:
+			bc->link_flags = str_lit("-arch arm ");
+			break;
+		default:
+			gb_printf_err("Compiler Error: Unsupported architecture\n");
+			gb_exit(1);
+		}
 	} else if (bc->metrics.arch == TargetArch_arm64) {
 		switch (bc->metrics.os) {
 		case TargetOs_darwin:
@@ -1152,8 +1168,195 @@ void init_build_context(TargetMetrics *cross_target) {
 
 	bc->optimization_level = gb_clamp(bc->optimization_level, 0, 3);
 
-
-
 	#undef LINK_FLAG_X64
 	#undef LINK_FLAG_386
 }
+
+#if defined(GB_SYSTEM_WINDOWS)
+// NOTE(IC): In order to find Visual C++ paths without relying on environment variables.
+// NOTE(Jeroen): No longer needed in `main.cpp -> linker_stage`. We now resolve those paths in `init_build_paths`.
+#include "microsoft_craziness.h"
+#endif
+
+// NOTE(Jeroen): Set/create the output and other paths and report an error as appropriate.
+// We've previously called `parse_build_flags`, so `out_filepath` should be set.
+bool init_build_paths(String init_filename) {
+	gbAllocator   ha = heap_allocator();
+	BuildContext *bc = &build_context;
+
+	// NOTE(Jeroen): We're pre-allocating BuildPathCOUNT slots so that certain paths are always at the same enumerated index.
+	array_init(&bc->build_paths, permanent_allocator(), BuildPathCOUNT);
+
+	// [BuildPathMainPackage] Turn given init path into a `Path`, which includes normalizing it into a full path.
+	bc->build_paths[BuildPath_Main_Package] = path_from_string(ha, init_filename);
+
+	bool produces_output_file = false;
+	if (bc->command_kind == Command_doc && bc->cmd_doc_flags & CmdDocFlag_DocFormat) {
+		produces_output_file = true;
+	} else if (bc->command_kind & Command__does_build) {
+		produces_output_file = true;
+	}
+
+	if (!produces_output_file) {
+		// Command doesn't produce output files. We're done.
+		return true;
+	}
+
+	#if defined(GB_SYSTEM_WINDOWS)
+		if (bc->resource_filepath.len > 0) {
+			bc->build_paths[BuildPath_RC]      = path_from_string(ha, bc->resource_filepath);
+			bc->build_paths[BuildPath_RES]     = path_from_string(ha, bc->resource_filepath);
+			bc->build_paths[BuildPath_RC].ext  = copy_string(ha, STR_LIT("rc"));
+			bc->build_paths[BuildPath_RES].ext = copy_string(ha, STR_LIT("res"));
+		}
+
+		if (bc->pdb_filepath.len > 0) {
+			bc->build_paths[BuildPath_PDB]          = path_from_string(ha, bc->pdb_filepath);
+		}
+
+		if ((bc->command_kind & Command__does_build) && (!bc->ignore_microsoft_magic)) {
+			// NOTE(ic): It would be nice to extend this so that we could specify the Visual Studio version that we want instead of defaulting to the latest.
+			Find_Result_Utf8 find_result = find_visual_studio_and_windows_sdk_utf8();
+
+			if (find_result.windows_sdk_version == 0) {
+				gb_printf_err("Windows SDK not found.\n");
+				return false;
+			}
+
+			if (find_result.windows_sdk_um_library_path.len > 0) {
+				GB_ASSERT(find_result.windows_sdk_ucrt_library_path.len > 0);
+
+				if (find_result.windows_sdk_root.len > 0) {
+					bc->build_paths[BuildPath_Win_SDK_Root]     = path_from_string(ha, find_result.windows_sdk_root);
+				}
+
+				if (find_result.windows_sdk_um_library_path.len > 0) {
+					bc->build_paths[BuildPath_Win_SDK_UM_Lib]   = path_from_string(ha, find_result.windows_sdk_um_library_path);
+				}
+
+				if (find_result.windows_sdk_ucrt_library_path.len > 0) {
+					bc->build_paths[BuildPath_Win_SDK_UCRT_Lib] = path_from_string(ha, find_result.windows_sdk_ucrt_library_path);
+				}
+
+				if (find_result.vs_exe_path.len > 0) {
+					bc->build_paths[BuildPath_VS_EXE]           = path_from_string(ha, find_result.vs_exe_path);
+				}
+
+				if (find_result.vs_library_path.len > 0) {
+					bc->build_paths[BuildPath_VS_LIB]           = path_from_string(ha, find_result.vs_library_path);
+				}
+			}
+
+			gb_free(ha, find_result.windows_sdk_root.text);
+			gb_free(ha, find_result.windows_sdk_um_library_path.text);
+			gb_free(ha, find_result.windows_sdk_ucrt_library_path.text);
+			gb_free(ha, find_result.vs_exe_path.text);
+			gb_free(ha, find_result.vs_library_path.text);
+
+		}
+	#endif
+
+	// All the build targets and OSes.
+	String output_extension;
+
+	if (bc->command_kind == Command_doc && bc->cmd_doc_flags & CmdDocFlag_DocFormat) {
+		output_extension = STR_LIT("odin-doc");
+	} else if (is_arch_wasm()) {
+		output_extension = STR_LIT("wasm");
+	} else if (build_context.build_mode == BuildMode_Executable) {
+		// By default use a .bin executable extension.
+		output_extension = STR_LIT("bin");
+
+		if (build_context.metrics.os == TargetOs_windows) {
+			output_extension = STR_LIT("exe");
+		} else if (build_context.cross_compiling && selected_target_metrics->metrics == &target_essence_amd64) {
+			output_extension = make_string(nullptr, 0);
+		}
+	} else if (build_context.build_mode == BuildMode_DynamicLibrary) {
+		// By default use a .so shared library extension.
+		output_extension = STR_LIT("so");
+
+		if (build_context.metrics.os == TargetOs_windows) {
+			output_extension = STR_LIT("dll");
+		} else if (build_context.metrics.os == TargetOs_darwin) {
+			output_extension = STR_LIT("dylib");
+		}
+	} else if (build_context.build_mode == BuildMode_Object) {
+		// By default use a .o object extension.
+		output_extension = STR_LIT("o");
+
+		if (build_context.metrics.os == TargetOs_windows) {
+			output_extension = STR_LIT("obj");
+		}
+	} else if (build_context.build_mode == BuildMode_Assembly) {
+		// By default use a .S asm extension.
+		output_extension = STR_LIT("S");
+	} else if (build_context.build_mode == BuildMode_LLVM_IR) {
+		output_extension = STR_LIT("ll");
+	} else {
+		GB_PANIC("Unhandled build mode/target combination.\n");
+	}
+
+	if (bc->out_filepath.len > 0) {
+		bc->build_paths[BuildPath_Output] = path_from_string(ha, bc->out_filepath);
+		if (build_context.metrics.os == TargetOs_windows) {
+			String output_file = path_to_string(ha, bc->build_paths[BuildPath_Output]);
+			defer (gb_free(ha, output_file.text));
+			if (path_is_directory(bc->build_paths[BuildPath_Output])) {
+				gb_printf_err("Output path %.*s is a directory.\n", LIT(output_file));
+				return false;
+			} else if (bc->build_paths[BuildPath_Output].ext.len == 0) {
+				gb_printf_err("Output path %.*s must have an appropriate extension.\n", LIT(output_file));
+				return false;				
+			}
+		}
+	} else {
+		Path output_path;
+
+		if (str_eq(init_filename, str_lit("."))) {
+			// We must name the output file after the current directory.
+			debugf("Output name will be created from current base name %.*s.\n", LIT(bc->build_paths[BuildPath_Main_Package].basename));
+			String last_element  = last_path_element(bc->build_paths[BuildPath_Main_Package].basename);
+
+			if (last_element.len == 0) {
+				gb_printf_err("The output name is created from the last path element. `%.*s` has none. Use `-out:output_name.ext` to set it.\n", LIT(bc->build_paths[BuildPath_Main_Package].basename));
+				return false;
+			}
+			output_path.basename = copy_string(ha, bc->build_paths[BuildPath_Main_Package].basename);
+			output_path.name     = copy_string(ha, last_element);
+
+		} else {
+			// Init filename was not 'current path'.
+			// Contruct the output name from the path elements as usual.
+			String output_name = remove_directory_from_path(init_filename);
+			output_name        = remove_extension_from_path(output_name);
+			output_name        = copy_string(ha, string_trim_whitespace(output_name));
+			output_path        = path_from_string(ha, output_name);
+
+			// Replace extension.
+			if (output_path.ext.len > 0) {
+				gb_free(ha, output_path.ext.text);
+			}
+		}
+		output_path.ext  = copy_string(ha, output_extension);
+
+		bc->build_paths[BuildPath_Output] = output_path;
+	}
+
+	// Do we have an extension? We might not if the output filename was supplied.
+	if (bc->build_paths[BuildPath_Output].ext.len == 0) {
+		if (build_context.metrics.os == TargetOs_windows || build_context.build_mode != BuildMode_Executable) {
+			bc->build_paths[BuildPath_Output].ext = copy_string(ha, output_extension);
+		}
+	}
+
+	// Check if output path is a directory.
+	if (path_is_directory(bc->build_paths[BuildPath_Output])) {
+		String output_file = path_to_string(ha, bc->build_paths[BuildPath_Output]);
+		defer (gb_free(ha, output_file.text));
+		gb_printf_err("Output path %.*s is a directory.\n", LIT(output_file));
+		return false;
+	}
+
+	return true;
+}
\ No newline at end of file
diff --git a/src/check_builtin.cpp b/src/check_builtin.cpp
index e055539c5..9a5d1c554 100644
--- a/src/check_builtin.cpp
+++ b/src/check_builtin.cpp
@@ -29,6 +29,7 @@ BuiltinTypeIsProc *builtin_type_is_procs[BuiltinProc__type_simple_boolean_end -
 
 	is_type_named,
 	is_type_pointer,
+	is_type_multi_pointer,
 	is_type_array,
 	is_type_enumerated_array,
 	is_type_slice,
@@ -3866,6 +3867,7 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 	case BuiltinProc_type_is_valid_matrix_elements:
 	case BuiltinProc_type_is_named:
 	case BuiltinProc_type_is_pointer:
+	case BuiltinProc_type_is_multi_pointer:
 	case BuiltinProc_type_is_array:
 	case BuiltinProc_type_is_enumerated_array:
 	case BuiltinProc_type_is_slice:
@@ -3926,6 +3928,37 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 			break;
 		}
 		break;
+	case BuiltinProc_type_field_type:
+		{
+			Operand op = {};
+			Type *bt = check_type(c, ce->args[0]);
+			Type *type = base_type(bt);
+			if (type == nullptr || type == t_invalid) {
+				error(ce->args[0], "Expected a type for '%.*s'", LIT(builtin_name));
+				return false;
+			}
+			Operand x = {};
+			check_expr(c, &x, ce->args[1]);
+
+			if (!is_type_string(x.type) || x.mode != Addressing_Constant || x.value.kind != ExactValue_String) {
+				error(ce->args[1], "Expected a const string for field argument");
+				return false;
+			}
+
+			String field_name = x.value.value_string;
+
+			Selection sel = lookup_field(type, field_name, false);
+			if (sel.index.count == 0) {
+				gbString t = type_to_string(type);
+				error(ce->args[1], "'%.*s' is not a field of type %s", LIT(field_name), t);
+				gb_string_free(t);
+				return false;
+			}
+			operand->mode = Addressing_Type;
+			operand->type = sel.entity->type;
+			break;
+		}
+		break;
 
 	case BuiltinProc_type_is_specialization_of:
 		{
diff --git a/src/check_decl.cpp b/src/check_decl.cpp
index 5acd56097..82ac6c677 100644
--- a/src/check_decl.cpp
+++ b/src/check_decl.cpp
@@ -1018,18 +1018,16 @@ void check_proc_decl(CheckerContext *ctx, Entity *e, DeclInfo *d) {
 		}
 		Entity *foreign_library = init_entity_foreign_library(ctx, e);
 		
-		if (is_arch_wasm()) {
+		if (is_arch_wasm() && foreign_library != nullptr) {
 			String module_name = str_lit("env");
-			if (foreign_library != nullptr) {
-				GB_ASSERT (foreign_library->kind == Entity_LibraryName);
-				if (foreign_library->LibraryName.paths.count != 1) {
-					error(foreign_library->token, "'foreign import' for '%.*s' architecture may only have one path, got %td", 
-					      LIT(target_arch_names[build_context.metrics.arch]), foreign_library->LibraryName.paths.count);
-				}
-				
-				if (foreign_library->LibraryName.paths.count >= 1) {
-					module_name = foreign_library->LibraryName.paths[0];
-				}
+			GB_ASSERT (foreign_library->kind == Entity_LibraryName);
+			if (foreign_library->LibraryName.paths.count != 1) {
+				error(foreign_library->token, "'foreign import' for '%.*s' architecture may only have one path, got %td",
+				      LIT(target_arch_names[build_context.metrics.arch]), foreign_library->LibraryName.paths.count);
+			}
+
+			if (foreign_library->LibraryName.paths.count >= 1) {
+				module_name = foreign_library->LibraryName.paths[0];
 			}
 			name = concatenate3_strings(permanent_allocator(), module_name, WASM_MODULE_NAME_SEPARATOR, name);
 		}
diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index dcf17af39..f578f8c73 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -7241,7 +7241,11 @@ ExprKind check_ternary_if_expr(CheckerContext *c, Operand *o, Ast *node, Type *t
 	node->viral_state_flags |= te->x->viral_state_flags;
 
 	if (te->y != nullptr) {
-		check_expr_or_type(c, &y, te->y, type_hint);
+		Type *th = type_hint;
+		if (type_hint == nullptr && is_type_typed(x.type)) {
+			th = x.type;
+		}
+		check_expr_or_type(c, &y, te->y, th);
 		node->viral_state_flags |= te->y->viral_state_flags;
 	} else {
 		error(node, "A ternary expression must have an else clause");
@@ -8161,7 +8165,10 @@ ExprKind check_compound_literal(CheckerContext *c, Operand *o, Ast *node, Type *
 	case Type_Basic: {
 		if (!is_type_any(t)) {
 			if (cl->elems.count != 0) {
-				error(node, "Illegal compound literal");
+				gbString s = type_to_string(t);
+				error(node, "Illegal compound literal, %s cannot be used as a compound literal with fields", s);
+				gb_string_free(s);
+				is_constant = false;
 			}
 			break;
 		}
diff --git a/src/checker.cpp b/src/checker.cpp
index 1bb786ea1..8afc6eb14 100644
--- a/src/checker.cpp
+++ b/src/checker.cpp
@@ -544,6 +544,28 @@ GB_COMPARE_PROC(vetted_entity_variable_pos_cmp) {
 	return token_pos_cmp(x->token.pos, y->token.pos);
 }
 
+bool check_vet_shadowing_assignment(Checker *c, Entity *shadowed, Ast *expr) {
+	Ast *init = unparen_expr(expr);
+	if (init == nullptr) {
+		return false;
+	}
+	if (init->kind == Ast_Ident) {
+		// TODO(bill): Which logic is better? Same name or same entity
+		// bool ignore = init->Ident.token.string == name;
+		bool ignore = init->Ident.entity == shadowed;
+		if (ignore) {
+			return true;
+		}
+	} else if (init->kind == Ast_TernaryIfExpr) {
+		bool x = check_vet_shadowing_assignment(c, shadowed, init->TernaryIfExpr.x);
+		bool y = check_vet_shadowing_assignment(c, shadowed, init->TernaryIfExpr.y);
+		if (x || y) {
+			return true;
+		}
+	}
+
+	return false;
+}
 
 
 bool check_vet_shadowing(Checker *c, Entity *e, VettedEntity *ve) {
@@ -594,17 +616,14 @@ bool check_vet_shadowing(Checker *c, Entity *e, VettedEntity *ve) {
 	}
 
 	// NOTE(bill): Ignore intentional redeclaration
-	// x := x;
+	// x := x
 	// Suggested in issue #637 (2020-05-11)
+	// Also allow the following
+	// x := x if cond else y
+	// x := z if cond else x
 	if ((e->flags & EntityFlag_Using) == 0 && e->kind == Entity_Variable) {
-		Ast *init = unparen_expr(e->Variable.init_expr);
-		if (init != nullptr && init->kind == Ast_Ident) {
-			// TODO(bill): Which logic is better? Same name or same entity
-			// bool ignore = init->Ident.token.string == name;
-			bool ignore = init->Ident.entity == shadowed;
-			if (ignore) {
-				return false;
-			}
+		if (check_vet_shadowing_assignment(c, shadowed, e->Variable.init_expr)) {
+			return false;
 		}
 	}
 
@@ -944,6 +963,7 @@ void init_universal(void) {
 			{"Unknown", TargetArch_Invalid},
 			{"amd64",   TargetArch_amd64},
 			{"i386",    TargetArch_i386},
+			{"arm32",   TargetArch_arm32},
 			{"arm64",   TargetArch_arm64},
 			{"wasm32",  TargetArch_wasm32},
 			{"wasm64",  TargetArch_wasm64},
@@ -4336,25 +4356,21 @@ void check_add_import_decl(CheckerContext *ctx, Ast *decl) {
 	}
 
 	String import_name = path_to_entity_name(id->import_name.string, id->fullpath, false);
+	if (is_blank_ident(import_name)) {
+		force_use = true;
+	}
 
 	// NOTE(bill, 2019-05-19): If the directory path is not a valid entity name, force the user to assign a custom one
 	// if (import_name.len == 0 || import_name == "_") {
 	// 	import_name = scope->pkg->name;
 	// }
 
-	if (import_name.len == 0 || is_blank_ident(import_name)) {
-		if (id->is_using) {
-			// TODO(bill): Should this be a warning?
-		} else {
-			if (id->import_name.string == "") {
-				String invalid_name = id->fullpath;
-				invalid_name = get_invalid_import_name(invalid_name);
+	if (import_name.len == 0) {
+		String invalid_name = id->fullpath;
+		invalid_name = get_invalid_import_name(invalid_name);
 
-				error(id->token, "Import name %.*s, is not a valid identifier. Perhaps you want to reference the package by a different name like this: import <new_name> \"%.*s\" ", LIT(invalid_name), LIT(invalid_name));
-			} else {
-				error(token, "Import name, %.*s, cannot be use as an import name as it is not a valid identifier", LIT(id->import_name.string));
-			}
-		}
+		error(id->token, "Import name %.*s, is not a valid identifier. Perhaps you want to reference the package by a different name like this: import <new_name> \"%.*s\" ", LIT(invalid_name), LIT(invalid_name));
+		error(token, "Import name, %.*s, cannot be use as an import name as it is not a valid identifier", LIT(id->import_name.string));
 	} else {
 		GB_ASSERT(id->import_name.pos.line != 0);
 		id->import_name.string = import_name;
@@ -4363,38 +4379,11 @@ void check_add_import_decl(CheckerContext *ctx, Ast *decl) {
 		                                     scope);
 
 		add_entity(ctx, parent_scope, nullptr, e);
-		if (force_use || id->is_using) {
+		if (force_use) {
 			add_entity_use(ctx, nullptr, e);
 		}
 	}
 
-	if (id->is_using) {
-		if (parent_scope->flags & ScopeFlag_Global) {
-			error(id->import_name, "built-in package imports cannot use using");
-			return;
-		}
-
-		// NOTE(bill): Add imported entities to this file's scope
-		for_array(elem_index, scope->elements.entries) {
-			String name = scope->elements.entries[elem_index].key.string;
-			Entity *e = scope->elements.entries[elem_index].value;
-			if (e->scope == parent_scope) continue;
-
-			if (is_entity_exported(e, true)) {
-				Entity *found = scope_lookup_current(parent_scope, name);
-				if (found != nullptr) {
-					// NOTE(bill):
-					// Date: 2019-03-17
-					// The order has to be the other way around as `using` adds the entity into the that
-					// file scope otherwise the error would be the wrong way around
-					redeclaration_error(name, found, e);
-				} else {
-					add_entity_with_name(ctx, parent_scope, e->identifier, e, name);
-				}
-			}
-		}
-	}
-
 	scope->flags |= ScopeFlag_HasBeenImported;
 }
 
@@ -4413,6 +4402,14 @@ DECL_ATTRIBUTE_PROC(foreign_import_decl_attribute) {
 		}
 		ac->require_declaration = true;
 		return true;
+	} else if (name == "priority_index") {
+		ExactValue ev = check_decl_attribute_value(c, value);
+		if (ev.kind != ExactValue_Integer) {
+			error(elem, "Expected an integer value for '%.*s'", LIT(name));
+		} else {
+			ac->foreign_import_priority_index = exact_value_to_i64(ev);
+		}
+		return true;
 	}
 	return false;
 }
@@ -4469,6 +4466,9 @@ void check_add_foreign_import_decl(CheckerContext *ctx, Ast *decl) {
 		mpmc_enqueue(&ctx->info->required_foreign_imports_through_force_queue, e);
 		add_entity_use(ctx, nullptr, e);
 	}
+	if (ac.foreign_import_priority_index != 0) {
+		e->LibraryName.priority_index = ac.foreign_import_priority_index;
+	}
 
 	if (has_asm_extension(fullpath)) {
 		if (build_context.metrics.arch != TargetArch_amd64 ||
diff --git a/src/checker.hpp b/src/checker.hpp
index 552e6aca7..1c9ffd8c7 100644
--- a/src/checker.hpp
+++ b/src/checker.hpp
@@ -118,6 +118,7 @@ struct AttributeContext {
 	bool    init                : 1;
 	bool    set_cold            : 1;
 	u32 optimization_mode; // ProcedureOptimizationMode
+	i64 foreign_import_priority_index;
 
 	String  objc_class;
 	String  objc_name;
diff --git a/src/checker_builtin_procs.hpp b/src/checker_builtin_procs.hpp
index fe14ae372..d301cae0c 100644
--- a/src/checker_builtin_procs.hpp
+++ b/src/checker_builtin_procs.hpp
@@ -158,6 +158,7 @@ BuiltinProc__type_simple_boolean_begin,
 
 	BuiltinProc_type_is_named,
 	BuiltinProc_type_is_pointer,
+	BuiltinProc_type_is_multi_pointer,
 	BuiltinProc_type_is_array,
 	BuiltinProc_type_is_enumerated_array,
 	BuiltinProc_type_is_slice,
@@ -179,6 +180,7 @@ BuiltinProc__type_simple_boolean_begin,
 BuiltinProc__type_simple_boolean_end,
 
 	BuiltinProc_type_has_field,
+	BuiltinProc_type_field_type,
 
 	BuiltinProc_type_is_specialization_of,
 
@@ -375,6 +377,7 @@ gb_global BuiltinProc builtin_procs[BuiltinProc_COUNT] = {
 
 	{STR_LIT("type_is_named"),             1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("type_is_pointer"),           1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_multi_pointer"),      1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("type_is_array"),             1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("type_is_enumerated_array"),  1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("type_is_slice"),             1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
@@ -395,6 +398,7 @@ gb_global BuiltinProc builtin_procs[BuiltinProc_COUNT] = {
 	{STR_LIT(""), 0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
 
 	{STR_LIT("type_has_field"),            2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_field_type"),           2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 
 	{STR_LIT("type_is_specialization_of"), 2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 
diff --git a/src/common.cpp b/src/common.cpp
index aaacda04b..94248fb62 100644
--- a/src/common.cpp
+++ b/src/common.cpp
@@ -675,262 +675,7 @@ wchar_t **command_line_to_wargv(wchar_t *cmd_line, int *_argc) {
 
 #endif
 
-
-#if defined(GB_SYSTEM_WINDOWS)
-	bool path_is_directory(String path) {
-		gbAllocator a = heap_allocator();
-		String16 wstr = string_to_string16(a, path);
-		defer (gb_free(a, wstr.text));
-
-		i32 attribs = GetFileAttributesW(wstr.text);
-		if (attribs < 0) return false;
-
-		return (attribs & FILE_ATTRIBUTE_DIRECTORY) != 0;
-	}
-
-#else
-	bool path_is_directory(String path) {
-		gbAllocator a = heap_allocator();
-		char *copy = cast(char *)copy_string(a, path).text;
-		defer (gb_free(a, copy));
-
-		struct stat s;
-		if (stat(copy, &s) == 0) {
-			return (s.st_mode & S_IFDIR) != 0;
-		}
-		return false;
-	}
-#endif
-
-
-String path_to_full_path(gbAllocator a, String path) {
-	gbAllocator ha = heap_allocator();
-	char *path_c = gb_alloc_str_len(ha, cast(char *)path.text, path.len);
-	defer (gb_free(ha, path_c));
-
-	char *fullpath = gb_path_get_full_name(a, path_c);
-	String res = string_trim_whitespace(make_string_c(fullpath));
-#if defined(GB_SYSTEM_WINDOWS)
-	for (isize i = 0; i < res.len; i++) {
-		if (res.text[i] == '\\') {
-			res.text[i] = '/';
-		}
-	}
-#endif
-	return res;
-}
-
-
-
-struct FileInfo {
-	String name;
-	String fullpath;
-	i64    size;
-	bool   is_dir;
-};
-
-enum ReadDirectoryError {
-	ReadDirectory_None,
-
-	ReadDirectory_InvalidPath,
-	ReadDirectory_NotExists,
-	ReadDirectory_Permission,
-	ReadDirectory_NotDir,
-	ReadDirectory_Empty,
-	ReadDirectory_Unknown,
-
-	ReadDirectory_COUNT,
-};
-
-i64 get_file_size(String path) {
-	char *c_str = alloc_cstring(heap_allocator(), path);
-	defer (gb_free(heap_allocator(), c_str));
-
-	gbFile f = {};
-	gbFileError err = gb_file_open(&f, c_str);
-	defer (gb_file_close(&f));
-	if (err != gbFileError_None) {
-		return -1;
-	}
-	return gb_file_size(&f);
-}
-
-
-#if defined(GB_SYSTEM_WINDOWS)
-ReadDirectoryError read_directory(String path, Array<FileInfo> *fi) {
-	GB_ASSERT(fi != nullptr);
-
-	gbAllocator a = heap_allocator();
-
-	while (path.len > 0) {
-		Rune end = path[path.len-1];
-		if (end == '/') {
-			path.len -= 1;
-		} else if (end == '\\') {
-			path.len -= 1;
-		} else {
-			break;
-		}
-	}
-
-	if (path.len == 0) {
-		return ReadDirectory_InvalidPath;
-	}
-	{
-		char *c_str = alloc_cstring(a, path);
-		defer (gb_free(a, c_str));
-
-		gbFile f = {};
-		gbFileError file_err = gb_file_open(&f, c_str);
-		defer (gb_file_close(&f));
-
-		switch (file_err) {
-		case gbFileError_Invalid:    return ReadDirectory_InvalidPath;
-		case gbFileError_NotExists:  return ReadDirectory_NotExists;
-		// case gbFileError_Permission: return ReadDirectory_Permission;
-		}
-	}
-
-	if (!path_is_directory(path)) {
-		return ReadDirectory_NotDir;
-	}
-
-
-	char *new_path = gb_alloc_array(a, char, path.len+3);
-	defer (gb_free(a, new_path));
-
-	gb_memmove(new_path, path.text, path.len);
-	gb_memmove(new_path+path.len, "/*", 2);
-	new_path[path.len+2] = 0;
-
-	String np = make_string(cast(u8 *)new_path, path.len+2);
-	String16 wstr = string_to_string16(a, np);
-	defer (gb_free(a, wstr.text));
-
-	WIN32_FIND_DATAW file_data = {};
-	HANDLE find_file = FindFirstFileW(wstr.text, &file_data);
-	if (find_file == INVALID_HANDLE_VALUE) {
-		return ReadDirectory_Unknown;
-	}
-	defer (FindClose(find_file));
-
-	array_init(fi, a, 0, 100);
-
-	do {
-		wchar_t *filename_w = file_data.cFileName;
-		i64 size = cast(i64)file_data.nFileSizeLow;
-		size |= (cast(i64)file_data.nFileSizeHigh) << 32;
-		String name = string16_to_string(a, make_string16_c(filename_w));
-		if (name == "." || name == "..") {
-			gb_free(a, name.text);
-			continue;
-		}
-
-		String filepath = {};
-		filepath.len = path.len+1+name.len;
-		filepath.text = gb_alloc_array(a, u8, filepath.len+1);
-		defer (gb_free(a, filepath.text));
-		gb_memmove(filepath.text, path.text, path.len);
-		gb_memmove(filepath.text+path.len, "/", 1);
-		gb_memmove(filepath.text+path.len+1, name.text, name.len);
-
-		FileInfo info = {};
-		info.name = name;
-		info.fullpath = path_to_full_path(a, filepath);
-		info.size = size;
-		info.is_dir = (file_data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
-		array_add(fi, info);
-	} while (FindNextFileW(find_file, &file_data));
-
-	if (fi->count == 0) {
-		return ReadDirectory_Empty;
-	}
-
-	return ReadDirectory_None;
-}
-#elif defined(GB_SYSTEM_LINUX) || defined(GB_SYSTEM_OSX) || defined(GB_SYSTEM_FREEBSD) || defined(GB_SYSTEM_OPENBSD)
-
-#include <dirent.h>
-
-ReadDirectoryError read_directory(String path, Array<FileInfo> *fi) {
-	GB_ASSERT(fi != nullptr);
-
-	gbAllocator a = heap_allocator();
-
-	char *c_path = alloc_cstring(a, path);
-	defer (gb_free(a, c_path));
-
-	DIR *dir = opendir(c_path);
-	if (!dir) {
-		switch (errno) {
-		case ENOENT:
-			return ReadDirectory_NotExists;
-		case EACCES:
-			return ReadDirectory_Permission;
-		case ENOTDIR:
-			return ReadDirectory_NotDir;
-		default:
-			// ENOMEM: out of memory
-			// EMFILE: per-process limit on open fds reached
-			// ENFILE: system-wide limit on total open files reached
-			return ReadDirectory_Unknown;
-		}
-		GB_PANIC("unreachable");
-	}
-
-	array_init(fi, a, 0, 100);
-
-	for (;;) {
-		struct dirent *entry = readdir(dir);
-		if (entry == nullptr) {
-			break;
-		}
-
-		String name = make_string_c(entry->d_name);
-		if (name == "." || name == "..") {
-			continue;
-		}
-
-		String filepath = {};
-		filepath.len = path.len+1+name.len;
-		filepath.text = gb_alloc_array(a, u8, filepath.len+1);
-		defer (gb_free(a, filepath.text));
-		gb_memmove(filepath.text, path.text, path.len);
-		gb_memmove(filepath.text+path.len, "/", 1);
-		gb_memmove(filepath.text+path.len+1, name.text, name.len);
-		filepath.text[filepath.len] = 0;
-
-
-		struct stat dir_stat = {};
-
-		if (stat((char *)filepath.text, &dir_stat)) {
-			continue;
-		}
-
-		if (S_ISDIR(dir_stat.st_mode)) {
-			continue;
-		}
-
-		i64 size = dir_stat.st_size;
-
-		FileInfo info = {};
-		info.name = name;
-		info.fullpath = path_to_full_path(a, filepath);
-		info.size = size;
-		array_add(fi, info);
-	}
-
-	if (fi->count == 0) {
-		return ReadDirectory_Empty;
-	}
-
-	return ReadDirectory_None;
-}
-#else
-#error Implement read_directory
-#endif
-
-
+#include "path.cpp"
 
 struct LoadedFile {
 	void *handle;
diff --git a/src/entity.cpp b/src/entity.cpp
index 1f87f7af6..904a630fb 100644
--- a/src/entity.cpp
+++ b/src/entity.cpp
@@ -252,6 +252,7 @@ struct Entity {
 		struct {
 			Slice<String> paths;
 			String name;
+			i64 priority_index;
 		} LibraryName;
 		i32 Nil;
 		struct {
diff --git a/src/exact_value.cpp b/src/exact_value.cpp
index f6df48951..175cb61f6 100644
--- a/src/exact_value.cpp
+++ b/src/exact_value.cpp
@@ -177,7 +177,11 @@ ExactValue exact_value_typeid(Type *type) {
 
 ExactValue exact_value_integer_from_string(String const &string) {
 	ExactValue result = {ExactValue_Integer};
-	big_int_from_string(&result.value_integer, string);
+	bool success;
+	big_int_from_string(&result.value_integer, string, &success);
+	if (!success) {
+		result = {ExactValue_Invalid};
+	}
 	return result;
 }
 
@@ -591,6 +595,7 @@ failure:
 i32 exact_value_order(ExactValue const &v) {
 	switch (v.kind) {
 	case ExactValue_Invalid:
+	case ExactValue_Compound:
 		return 0;
 	case ExactValue_Bool:
 	case ExactValue_String:
@@ -607,8 +612,6 @@ i32 exact_value_order(ExactValue const &v) {
 		return 6;
 	case ExactValue_Procedure:
 		return 7;
-	// case ExactValue_Compound:
-		// return 8;
 
 	default:
 		GB_PANIC("How'd you get here? Invalid Value.kind %d", v.kind);
diff --git a/src/gb/gb.h b/src/gb/gb.h
index b72a893f7..3b2d6434c 100644
--- a/src/gb/gb.h
+++ b/src/gb/gb.h
@@ -6273,20 +6273,44 @@ char *gb_path_get_full_name(gbAllocator a, char const *path) {
 #else
 	char *p, *result, *fullpath = NULL;
 	isize len;
-	p = realpath(path, NULL);
-	fullpath = p;
-	if (p == NULL) {
-		// NOTE(bill): File does not exist
-		fullpath = cast(char *)path;
-	}
+	fullpath = realpath(path, NULL);
+
+	if (fullpath == NULL) {
+		// NOTE(Jeroen): Path doesn't exist.
+		if (gb_strlen(path) > 0 && path[0] == '/') {
+			// But it is an absolute path, so return as-is.
+
+			fullpath = (char *)path;
+			len      = gb_strlen(fullpath) + 1;
+			result   = gb_alloc_array(a, char, len + 1);
+
+			gb_memmove(result, fullpath, len);
+			result[len] = 0;
+
+		} else {
+			// Appears to be a relative path, so construct an absolute one relative to <cwd>.
+			char cwd[4096];
+			getcwd(&cwd[0], 4096);
+
+			isize path_len = gb_strlen(path);
+			isize cwd_len  = gb_strlen(cwd);
+			len            = cwd_len + 1 + path_len + 1;
+			result         = gb_alloc_array(a, char, len);
 
-	len = gb_strlen(fullpath);
+			gb_memmove(result, (void *)cwd, cwd_len);
+			result[cwd_len] = '/';
 
-	result = gb_alloc_array(a, char, len + 1);
-	gb_memmove(result, fullpath, len);
-	result[len] = 0;
-	free(p);
+			gb_memmove(result + cwd_len + 1, (void *)path, gb_strlen(path));
+			result[len] = 0;
 
+		}
+	} else {
+		len      = gb_strlen(fullpath) + 1;
+		result   = gb_alloc_array(a, char, len + 1);
+		gb_memmove(result, fullpath, len);
+		result[len] = 0;
+		free(fullpath);
+	}
 	return result;
 #endif
 }
diff --git a/src/llvm_abi.cpp b/src/llvm_abi.cpp
index 07d2dd6e3..c6ff12f95 100644
--- a/src/llvm_abi.cpp
+++ b/src/llvm_abi.cpp
@@ -516,6 +516,10 @@ namespace lbAbiAmd64SysV {
 
 	bool is_register(LLVMTypeRef type) {
 		LLVMTypeKind kind = LLVMGetTypeKind(type);
+		i64 sz = lb_sizeof(type);
+		if (sz == 0) {
+			return false;
+		}
 		switch (kind) {
 		case LLVMIntegerTypeKind:
 		case LLVMHalfTypeKind:
@@ -1164,6 +1168,88 @@ namespace lbAbiWasm32 {
 	}
 }
 
+namespace lbAbiArm32 {
+	Array<lbArgType> compute_arg_types(LLVMContextRef c, LLVMTypeRef *arg_types, unsigned arg_count, ProcCallingConvention calling_convention);
+	lbArgType compute_return_type(LLVMContextRef c, LLVMTypeRef return_type, bool return_is_defined);
+
+	LB_ABI_INFO(abi_info) {
+		lbFunctionType *ft = gb_alloc_item(permanent_allocator(), lbFunctionType);
+		ft->ctx = c;
+		ft->args = compute_arg_types(c, arg_types, arg_count, calling_convention);
+		ft->ret = compute_return_type(c, return_type, return_is_defined);
+		ft->calling_convention = calling_convention;
+		return ft;
+	}
+
+	bool is_register(LLVMTypeRef type, bool is_return) {
+		LLVMTypeKind kind = LLVMGetTypeKind(type);
+		switch (kind) {
+		case LLVMHalfTypeKind:
+		case LLVMFloatTypeKind:
+		case LLVMDoubleTypeKind:
+			return true;
+		case LLVMIntegerTypeKind:
+			return lb_sizeof(type) <= 8;
+		case LLVMFunctionTypeKind:
+			return true;
+		case LLVMPointerTypeKind:
+			return true;
+		case LLVMVectorTypeKind:
+			return true;
+		}
+		return false;
+	}
+
+	lbArgType non_struct(LLVMContextRef c, LLVMTypeRef type, bool is_return) {
+		LLVMAttributeRef attr = nullptr;
+		LLVMTypeRef i1 = LLVMInt1TypeInContext(c);
+		if (type == i1) {
+			attr = lb_create_enum_attribute(c, "zeroext");
+		}
+		return lb_arg_type_direct(type, nullptr, nullptr, attr);
+	}
+
+	Array<lbArgType> compute_arg_types(LLVMContextRef c, LLVMTypeRef *arg_types, unsigned arg_count, ProcCallingConvention calling_convention) {
+		auto args = array_make<lbArgType>(heap_allocator(), arg_count);
+
+		for (unsigned i = 0; i < arg_count; i++) {
+			LLVMTypeRef t = arg_types[i];
+			if (is_register(t, false)) {
+				args[i] = non_struct(c, t, false);
+			} else {
+				i64 sz = lb_sizeof(t);
+				i64 a = lb_alignof(t);
+				if (is_calling_convention_odin(calling_convention) && sz > 8) {
+					// Minor change to improve performance using the Odin calling conventions
+					args[i] = lb_arg_type_indirect(t, nullptr);
+				} else if (a <= 4) {
+					unsigned n = cast(unsigned)((sz + 3) / 4);
+					args[i] = lb_arg_type_direct(LLVMArrayType(LLVMIntTypeInContext(c, 32), n));
+				} else {
+					unsigned n = cast(unsigned)((sz + 7) / 8);
+					args[i] = lb_arg_type_direct(LLVMArrayType(LLVMIntTypeInContext(c, 64), n));
+				}
+			}
+		}
+		return args;
+	}
+
+	lbArgType compute_return_type(LLVMContextRef c, LLVMTypeRef return_type, bool return_is_defined) {
+		if (!return_is_defined) {
+			return lb_arg_type_direct(LLVMVoidTypeInContext(c));
+		} else if (!is_register(return_type, true)) {
+			switch (lb_sizeof(return_type)) {
+			case 1:         return lb_arg_type_direct(LLVMIntTypeInContext(c, 8),  return_type, nullptr, nullptr);
+			case 2:         return lb_arg_type_direct(LLVMIntTypeInContext(c, 16), return_type, nullptr, nullptr);
+			case 3: case 4: return lb_arg_type_direct(LLVMIntTypeInContext(c, 32), return_type, nullptr, nullptr);
+			}
+			LLVMAttributeRef attr = lb_create_enum_attribute_with_type(c, "sret", return_type);
+			return lb_arg_type_indirect(return_type, attr);
+		}
+		return non_struct(c, return_type, true);
+	}
+};
+
 
 LB_ABI_INFO(lb_get_abi_info) {
 	switch (calling_convention) {
@@ -1203,6 +1289,8 @@ LB_ABI_INFO(lb_get_abi_info) {
 		}
 	case TargetArch_i386:
 		return lbAbi386::abi_info(c, arg_types, arg_count, return_type, return_is_defined, calling_convention);
+	case TargetArch_arm32:
+		return lbAbiArm32::abi_info(c, arg_types, arg_count, return_type, return_is_defined, calling_convention);
 	case TargetArch_arm64:
 		return lbAbiArm64::abi_info(c, arg_types, arg_count, return_type, return_is_defined, calling_convention);
 	case TargetArch_wasm32:
diff --git a/src/llvm_backend.cpp b/src/llvm_backend.cpp
index f5cb84785..7cf588853 100644
--- a/src/llvm_backend.cpp
+++ b/src/llvm_backend.cpp
@@ -29,29 +29,53 @@ void lb_add_foreign_library_path(lbModule *m, Entity *e) {
 	GB_ASSERT(e->kind == Entity_LibraryName);
 	GB_ASSERT(e->flags & EntityFlag_Used);
 
-	for_array(i, e->LibraryName.paths) {
-		String library_path = e->LibraryName.paths[i];
-		if (library_path.len == 0) {
-			continue;
-		}
+	mutex_lock(&m->gen->foreign_mutex);
+	if (!ptr_set_update(&m->gen->foreign_libraries_set, e)) {
+		array_add(&m->gen->foreign_libraries, e);
+	}
+	mutex_unlock(&m->gen->foreign_mutex);
+}
 
-		bool ok = true;
-		for_array(path_index, m->foreign_library_paths) {
-			String path = m->foreign_library_paths[path_index];
-	#if defined(GB_SYSTEM_WINDOWS)
-			if (str_eq_ignore_case(path, library_path)) {
-	#else
-			if (str_eq(path, library_path)) {
-	#endif
-				ok = false;
-				break;
-			}
+GB_COMPARE_PROC(foreign_library_cmp) {
+	int cmp = 0;
+	Entity *x = *(Entity **)a;
+	Entity *y = *(Entity **)b;
+	if (x == y) {
+		return 0;
+	}
+	GB_ASSERT(x->kind == Entity_LibraryName);
+	GB_ASSERT(y->kind == Entity_LibraryName);
+
+	cmp = i64_cmp(x->LibraryName.priority_index, y->LibraryName.priority_index);
+	if (cmp) {
+		return cmp;
+	}
+
+	if (x->pkg != y->pkg) {
+		isize order_x = x->pkg ? x->pkg->order : 0;
+		isize order_y = y->pkg ? y->pkg->order : 0;
+		cmp = isize_cmp(order_x, order_y);
+		if (cmp) {
+			return cmp;
 		}
+	}
+	if (x->file != y->file) {
+		String fullpath_x = x->file ? x->file->fullpath : (String{});
+		String fullpath_y = y->file ? y->file->fullpath : (String{});
+		String file_x = filename_from_path(fullpath_x);
+		String file_y = filename_from_path(fullpath_y);
 
-		if (ok) {
-			array_add(&m->foreign_library_paths, library_path);
+		cmp = string_compare(file_x, file_y);
+		if (cmp) {
+			return cmp;
 		}
 	}
+
+	cmp = u64_cmp(x->order_in_src, y->order_in_src);
+	if (cmp) {
+		return cmp;
+	}
+	return i32_cmp(x->token.pos.offset, y->token.pos.offset);
 }
 
 void lb_set_entity_from_other_modules_linkage_correctly(lbModule *other_module, Entity *e, String const &name) {
@@ -967,7 +991,12 @@ lbProcedure *lb_create_main_procedure(lbModule *m, lbProcedure *startup_runtime)
 }
 
 String lb_filepath_ll_for_module(lbModule *m) {
-	String path = m->gen->output_base;
+	String path = concatenate3_strings(permanent_allocator(),
+		build_context.build_paths[BuildPath_Output].basename,
+		STR_LIT("/"),
+		build_context.build_paths[BuildPath_Output].name
+	);
+
 	if (m->pkg) {
 		path = concatenate3_strings(permanent_allocator(), path, STR_LIT("-"), m->pkg->name);
 	} else if (USE_SEPARATE_MODULES) {
@@ -978,7 +1007,12 @@ String lb_filepath_ll_for_module(lbModule *m) {
 	return path;
 }
 String lb_filepath_obj_for_module(lbModule *m) {
-	String path = m->gen->output_base;
+	String path = concatenate3_strings(permanent_allocator(),
+		build_context.build_paths[BuildPath_Output].basename,
+		STR_LIT("/"),
+		build_context.build_paths[BuildPath_Output].name
+	);
+
 	if (m->pkg) {
 		path = concatenate3_strings(permanent_allocator(), path, STR_LIT("-"), m->pkg->name);
 	}
@@ -1912,4 +1946,6 @@ void lb_generate_code(lbGenerator *gen) {
 			}
 		}
 	}
+
+	gb_sort_array(gen->foreign_libraries.data, gen->foreign_libraries.count, foreign_library_cmp);
 }
diff --git a/src/llvm_backend.hpp b/src/llvm_backend.hpp
index f2bcfaff6..a460b1a23 100644
--- a/src/llvm_backend.hpp
+++ b/src/llvm_backend.hpp
@@ -135,7 +135,6 @@ struct lbModule {
 	u32 nested_type_name_guid;
 
 	Array<lbProcedure *> procedures_to_generate;
-	Array<String> foreign_library_paths;
 
 	lbProcedure *curr_procedure;
 
@@ -162,6 +161,10 @@ struct lbGenerator {
 
 	PtrMap<Ast *, lbProcedure *> anonymous_proc_lits; 
 
+	BlockingMutex foreign_mutex;
+	PtrSet<Entity *> foreign_libraries_set;
+	Array<Entity *>  foreign_libraries;
+
 	std::atomic<u32> global_array_index;
 	std::atomic<u32> global_generated_index;
 };
diff --git a/src/llvm_backend_general.cpp b/src/llvm_backend_general.cpp
index 330059622..0866e3687 100644
--- a/src/llvm_backend_general.cpp
+++ b/src/llvm_backend_general.cpp
@@ -67,9 +67,7 @@ void lb_init_module(lbModule *m, Checker *c) {
 	map_init(&m->equal_procs, a);
 	map_init(&m->hasher_procs, a);
 	array_init(&m->procedures_to_generate, a, 0, 1024);
-	array_init(&m->foreign_library_paths,  a, 0, 1024);
 	array_init(&m->missing_procedures_to_check, a, 0, 16);
-
 	map_init(&m->debug_values, a);
 	array_init(&m->debug_incomplete_types, a, 0, 1024);
 
@@ -87,7 +85,6 @@ bool lb_init_generator(lbGenerator *gen, Checker *c) {
 		return false;
 	}
 
-
 	String init_fullpath = c->parser->init_fullpath;
 
 	if (build_context.out_filepath.len == 0) {
@@ -127,6 +124,11 @@ bool lb_init_generator(lbGenerator *gen, Checker *c) {
 	map_init(&gen->modules_through_ctx, permanent_allocator(), gen->info->packages.entries.count*2);
 	map_init(&gen->anonymous_proc_lits, heap_allocator(), 1024);
 
+
+	mutex_init(&gen->foreign_mutex);
+	array_init(&gen->foreign_libraries,       heap_allocator(), 0, 1024);
+	ptr_set_init(&gen->foreign_libraries_set, heap_allocator(), 1024);
+
 	if (USE_SEPARATE_MODULES) {
 		for_array(i, gen->info->packages.entries) {
 			AstPackage *pkg = gen->info->packages.entries[i].value;
diff --git a/src/llvm_backend_proc.cpp b/src/llvm_backend_proc.cpp
index 96ff19d10..a0e9a5da5 100644
--- a/src/llvm_backend_proc.cpp
+++ b/src/llvm_backend_proc.cpp
@@ -189,7 +189,7 @@ lbProcedure *lb_create_procedure(lbModule *m, Entity *entity, bool ignore_body)
 				GB_ASSERT(entity->kind == Entity_Procedure);
 				String link_name = entity->Procedure.link_name;
 				if (entity->flags & EntityFlag_CustomLinkName && 
-				    link_name != "") {
+					link_name != "") {
 					if (string_starts_with(link_name, str_lit("__"))) {
 						LLVMSetLinkage(p->value, LLVMExternalLinkage);
 					} else {
@@ -200,12 +200,12 @@ lbProcedure *lb_create_procedure(lbModule *m, Entity *entity, bool ignore_body)
 		}
 	}
 	lb_set_linkage_from_entity_flags(p->module, p->value, entity->flags);
-	
-	
+
+
 	if (p->is_foreign) {
 		lb_set_wasm_import_attributes(p->value, entity, p->name);
 	}
-	
+
 
 	// NOTE(bill): offset==0 is the return value
 	isize offset = 1;
@@ -280,7 +280,7 @@ lbProcedure *lb_create_procedure(lbModule *m, Entity *entity, bool ignore_body)
 		if (p->body != nullptr) {
 			// String debug_name = entity->token.string.text;
 			String debug_name = p->name;
-			
+
 			p->debug_info = LLVMDIBuilderCreateFunction(m->debug_builder, scope,
 				cast(char const *)debug_name.text, debug_name.len,
 				cast(char const *)p->name.text, p->name.len,
@@ -823,12 +823,6 @@ lbValue lb_emit_call(lbProcedure *p, lbValue value, Array<lbValue> const &args,
 	GB_ASSERT(pt->kind == Type_Proc);
 	Type *results = pt->Proc.results;
 
-	if (p->entity != nullptr) {
-		if (p->entity->flags & EntityFlag_Disabled) {
-			return {};
-		}
-	}
-
 	lbAddr context_ptr = {};
 	if (pt->Proc.calling_convention == ProcCC_Odin) {
 		context_ptr = lb_find_or_generate_context_ptr(p);
@@ -1315,22 +1309,22 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 
 	case BuiltinProc_clamp:
 		return lb_emit_clamp(p, type_of_expr(expr),
-		                     lb_build_expr(p, ce->args[0]),
-		                     lb_build_expr(p, ce->args[1]),
-		                     lb_build_expr(p, ce->args[2]));
+							 lb_build_expr(p, ce->args[0]),
+							 lb_build_expr(p, ce->args[1]),
+							 lb_build_expr(p, ce->args[2]));
 
 
 	case BuiltinProc_soa_zip:
 		return lb_soa_zip(p, ce, tv);
 	case BuiltinProc_soa_unzip:
 		return lb_soa_unzip(p, ce, tv);
-		
+
 	case BuiltinProc_transpose:
 		{
 			lbValue m = lb_build_expr(p, ce->args[0]);
 			return lb_emit_matrix_tranpose(p, m, tv.type);
 		}
-		
+
 	case BuiltinProc_outer_product:
 		{
 			lbValue a = lb_build_expr(p, ce->args[0]);
@@ -1347,13 +1341,13 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 			GB_ASSERT(is_type_matrix(tv.type));
 			return lb_emit_arith_matrix(p, Token_Mul, a, b, tv.type, true);
 		}
-		
+
 	case BuiltinProc_matrix_flatten:
 		{
 			lbValue m = lb_build_expr(p, ce->args[0]);
 			return lb_emit_matrix_flatten(p, m, tv.type);
 		}
-		
+
 	// "Intrinsics"
 
 	case BuiltinProc_alloca:
@@ -1370,7 +1364,7 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 
 	case BuiltinProc_cpu_relax:
 		if (build_context.metrics.arch == TargetArch_i386 ||
-		    build_context.metrics.arch == TargetArch_amd64) {
+			build_context.metrics.arch == TargetArch_amd64) {
 			LLVMTypeRef func_type = LLVMFunctionType(LLVMVoidTypeInContext(p->module->ctx), nullptr, 0, false);
 			LLVMValueRef the_asm = llvm_get_inline_asm(func_type, str_lit("pause"), {}, true);
 			GB_ASSERT(the_asm != nullptr);
@@ -1538,7 +1532,7 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 			lbValue dst = lb_build_expr(p, ce->args[0]);
 			lbValue src = lb_build_expr(p, ce->args[1]);
 			lbValue len = lb_build_expr(p, ce->args[2]);
-			
+
 			lb_mem_copy_overlapping(p, dst, src, len, false);
 			return {};
 		}
@@ -1547,7 +1541,7 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 			lbValue dst = lb_build_expr(p, ce->args[0]);
 			lbValue src = lb_build_expr(p, ce->args[1]);
 			lbValue len = lb_build_expr(p, ce->args[2]);
-			
+
 			lb_mem_copy_non_overlapping(p, dst, src, len, false);
 			return {};
 		}
@@ -1651,7 +1645,7 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 		res.type = type_deref(dst.type);
 		return res;
 	}
-	
+
 	case BuiltinProc_unaligned_store:
 		{
 			lbValue dst = lb_build_expr(p, ce->args[0]);
@@ -1661,7 +1655,7 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 			lb_mem_copy_non_overlapping(p, dst, src, lb_const_int(p->module, t_int, type_size_of(t)), false);
 			return {};
 		}
-	
+
 	case BuiltinProc_unaligned_load:
 		{
 			lbValue src = lb_build_expr(p, ce->args[0]);
@@ -1843,7 +1837,7 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 			res.type = t;
 			return lb_emit_conv(p, res, t);
 		}
-		
+
 	case BuiltinProc_prefetch_read_instruction:
 	case BuiltinProc_prefetch_read_data:
 	case BuiltinProc_prefetch_write_instruction:
@@ -1871,27 +1865,27 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 				cache = 1;
 				break;
 			}
-			
+
 			char const *name = "llvm.prefetch";
-			
+
 			LLVMTypeRef types[1] = {lb_type(p->module, t_rawptr)};
 			unsigned id = LLVMLookupIntrinsicID(name, gb_strlen(name));
 			GB_ASSERT_MSG(id != 0, "Unable to find %s.%s", name, LLVMPrintTypeToString(types[0]));
 			LLVMValueRef ip = LLVMGetIntrinsicDeclaration(p->module->mod, id, types, gb_count_of(types));
-			
+
 			LLVMTypeRef llvm_i32 = lb_type(p->module, t_i32);
 			LLVMValueRef args[4] = {};
 			args[0] = ptr.value;
 			args[1] = LLVMConstInt(llvm_i32, rw, false);
 			args[2] = LLVMConstInt(llvm_i32, locality, false);
 			args[3] = LLVMConstInt(llvm_i32, cache, false);
-			
+
 			lbValue res = {};
 			res.value = LLVMBuildCall(p->builder, ip, args, gb_count_of(args), "");
 			res.type = nullptr;
 			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);
@@ -1909,22 +1903,22 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 				arg = lb_emit_conv(p, arg, t_uintptr);
 				args[i] = arg.value;
 			}
-			
+
 			LLVMTypeRef llvm_uintptr = lb_type(p->module, t_uintptr);
 			LLVMTypeRef *llvm_arg_types = gb_alloc_array(permanent_allocator(), LLVMTypeRef, arg_count);
 			for (unsigned i = 0; i < arg_count; i++) {
 				llvm_arg_types[i] = llvm_uintptr;
 			}
-			
+
 			LLVMTypeRef func_type = LLVMFunctionType(llvm_uintptr, llvm_arg_types, arg_count, false);
-			
+
 			LLVMValueRef inline_asm = nullptr;
-			
+
 			switch (build_context.metrics.arch) {
 			case TargetArch_amd64:
 				{
 					GB_ASSERT(arg_count <= 7);
-					
+
 					char asm_string[] = "syscall";
 					gbString constraints = gb_string_make(heap_allocator(), "={rax}");
 					for (unsigned i = 0; i < arg_count; i++) {
@@ -1963,11 +1957,11 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 			case TargetArch_i386:
 				{
 					GB_ASSERT(arg_count <= 7);
-					
+
 					char asm_string_default[] = "int $0x80";
 					char *asm_string = asm_string_default;
 					gbString constraints = gb_string_make(heap_allocator(), "={eax}");
-					
+
 					for (unsigned i = 0; i < gb_min(arg_count, 6); i++) {
 						constraints = gb_string_appendc(constraints, ",{");
 						static char const *regs[] = {
@@ -1984,56 +1978,81 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 					if (arg_count == 7) {
 						char asm_string7[] = "push %[arg6]\npush %%ebp\nmov 4(%%esp), %%ebp\nint $0x80\npop %%ebp\nadd $4, %%esp";
 						asm_string = asm_string7;
-						
+
 						constraints = gb_string_appendc(constraints, ",rm");
 					}
-					
+
 					inline_asm = llvm_get_inline_asm(func_type, make_string_c(asm_string), make_string_c(constraints));
 				}
 				break;
 			case TargetArch_arm64:
 				{
-                    GB_ASSERT(arg_count <= 7);
-                    
-                    if(build_context.metrics.os == TargetOs_darwin) {
-                        char asm_string[] = "svc #0x80";
-                        gbString constraints = gb_string_make(heap_allocator(), "={x0}");
-                        for (unsigned i = 0; i < arg_count; i++) {
-                            constraints = gb_string_appendc(constraints, ",{");
-                            static char const *regs[] = {
-                                "x16",
-                                "x0",
-                                "x1",
-                                "x2",
-                                "x3",
-                                "x4",
-                                "x5",
-                            };
-                            constraints = gb_string_appendc(constraints, regs[i]);
-                            constraints = gb_string_appendc(constraints, "}");
-                        }
-
-                        inline_asm = llvm_get_inline_asm(func_type, make_string_c(asm_string), make_string_c(constraints));
-                    } else {
-                        char asm_string[] = "svc #0";
-                        gbString constraints = gb_string_make(heap_allocator(), "={x0}");
-                        for (unsigned i = 0; i < arg_count; i++) {
-                            constraints = gb_string_appendc(constraints, ",{");
-                            static char const *regs[] = {
-                                "x8",
-                                "x0",
-                                "x1",
-                                "x2",
-                                "x3",
-                                "x4",
-                                "x5",
-                            };
-                            constraints = gb_string_appendc(constraints, regs[i]);
-                            constraints = gb_string_appendc(constraints, "}");
-                        }
-
-                        inline_asm = llvm_get_inline_asm(func_type, make_string_c(asm_string), make_string_c(constraints));
-                    }
+					GB_ASSERT(arg_count <= 7);
+
+					if(build_context.metrics.os == TargetOs_darwin) {
+						char asm_string[] = "svc #0x80";
+						gbString constraints = gb_string_make(heap_allocator(), "={x0}");
+						for (unsigned i = 0; i < arg_count; i++) {
+							constraints = gb_string_appendc(constraints, ",{");
+							static char const *regs[] = {
+								"x16",
+								"x0",
+								"x1",
+								"x2",
+								"x3",
+								"x4",
+								"x5",
+							};
+							constraints = gb_string_appendc(constraints, regs[i]);
+							constraints = gb_string_appendc(constraints, "}");
+						}
+
+						inline_asm = llvm_get_inline_asm(func_type, make_string_c(asm_string), make_string_c(constraints));
+					} else {
+						char asm_string[] = "svc #0";
+						gbString constraints = gb_string_make(heap_allocator(), "={x0}");
+						for (unsigned i = 0; i < arg_count; i++) {
+							constraints = gb_string_appendc(constraints, ",{");
+							static char const *regs[] = {
+								"x8",
+								"x0",
+								"x1",
+								"x2",
+								"x3",
+								"x4",
+								"x5",
+							};
+							constraints = gb_string_appendc(constraints, regs[i]);
+							constraints = gb_string_appendc(constraints, "}");
+						}
+
+						inline_asm = llvm_get_inline_asm(func_type, make_string_c(asm_string), make_string_c(constraints));
+					}
+				}
+				break;
+			case TargetArch_arm32:
+				{
+					// TODO(bill): Check this is correct
+					GB_ASSERT(arg_count <= 7);
+
+					char asm_string[] = "svc #0";
+					gbString constraints = gb_string_make(heap_allocator(), "={r0}");
+					for (unsigned i = 0; i < arg_count; i++) {
+						constraints = gb_string_appendc(constraints, ",{");
+						static char const *regs[] = {
+							"r8",
+							"r0",
+							"r1",
+							"r2",
+							"r3",
+							"r4",
+							"r5",
+						};
+						constraints = gb_string_appendc(constraints, regs[i]);
+						constraints = gb_string_appendc(constraints, "}");
+					}
+
+					inline_asm = llvm_get_inline_asm(func_type, make_string_c(asm_string), make_string_c(constraints));
 				}
 				break;
 			default:
@@ -2255,6 +2274,15 @@ lbValue lb_build_call_expr_internal(lbProcedure *p, Ast *expr) {
 	// NOTE(bill): Regular call
 	lbValue value = {};
 	Ast *proc_expr = unparen_expr(ce->proc);
+
+	Entity *proc_entity = entity_of_node(proc_expr);
+	if (proc_entity != nullptr) {
+		if (proc_entity->flags & EntityFlag_Disabled) {
+			GB_ASSERT(tv.type == nullptr);
+			return {};
+		}
+	}
+
 	if (proc_expr->tav.mode == Addressing_Constant) {
 		ExactValue v = proc_expr->tav.value;
 		switch (v.kind) {
@@ -2281,13 +2309,6 @@ lbValue lb_build_call_expr_internal(lbProcedure *p, Ast *expr) {
 		}
 	}
 
-	Entity *proc_entity = entity_of_node(proc_expr);
-	if (proc_entity != nullptr) {
-		if (proc_entity->flags & EntityFlag_Disabled) {
-			return {};
-		}
-	}
-
 	if (value.value == nullptr) {
 		value = lb_build_expr(p, proc_expr);
 	}
diff --git a/src/main.cpp b/src/main.cpp
index fc8792ceb..561fa0fca 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -46,7 +46,6 @@ gb_global Timings global_timings = {0};
 #include "checker.cpp"
 #include "docs.cpp"
 
-
 #include "llvm_backend.cpp"
 
 #if defined(GB_SYSTEM_OSX)
@@ -57,16 +56,8 @@ gb_global Timings global_timings = {0};
 #endif
 
 #include "query_data.cpp"
-
-
-#if defined(GB_SYSTEM_WINDOWS)
-// NOTE(IC): In order to find Visual C++ paths without relying on environment variables.
-#include "microsoft_craziness.h"
-#endif
-
 #include "bug_report.cpp"
 
-
 // NOTE(bill): 'name' is used in debugging and profiling modes
 i32 system_exec_command_line_app(char const *name, char const *fmt, ...) {
 	isize const cmd_cap = 64<<20; // 64 MiB should be more than enough
@@ -130,34 +121,35 @@ i32 system_exec_command_line_app(char const *name, char const *fmt, ...) {
 }
 
 
-
-
 i32 linker_stage(lbGenerator *gen) {
 	i32 result = 0;
 	Timings *timings = &global_timings;
 
-	String output_base = gen->output_base;
+	String output_filename = path_to_string(heap_allocator(), build_context.build_paths[BuildPath_Output]);
+	debugf("Linking %.*s\n", LIT(output_filename));
+
+	// TOOD(Jeroen): Make a `build_paths[BuildPath_Object] to avoid `%.*s.o`.
 
 	if (is_arch_wasm()) {
 		timings_start_section(timings, str_lit("wasm-ld"));
 
 	#if defined(GB_SYSTEM_WINDOWS)
 		result = system_exec_command_line_app("wasm-ld",
-			"\"%.*s\\bin\\wasm-ld\" \"%.*s.wasm.o\" -o \"%.*s.wasm\" %.*s %.*s",
+			"\"%.*s\\bin\\wasm-ld\" \"%.*s.o\" -o \"%.*s\" %.*s %.*s",
 			LIT(build_context.ODIN_ROOT),
-			LIT(output_base), LIT(output_base), LIT(build_context.link_flags), LIT(build_context.extra_linker_flags));
+			LIT(output_filename), LIT(output_filename), LIT(build_context.link_flags), LIT(build_context.extra_linker_flags));
 	#else
 		result = system_exec_command_line_app("wasm-ld",
-			"wasm-ld \"%.*s.wasm.o\" -o \"%.*s.wasm\" %.*s %.*s",
-			LIT(output_base), LIT(output_base), LIT(build_context.link_flags), LIT(build_context.extra_linker_flags));
+			"wasm-ld \"%.*s.o\" -o \"%.*s\" %.*s %.*s",
+			LIT(output_filename), LIT(output_filename), LIT(build_context.link_flags), LIT(build_context.extra_linker_flags));
 	#endif
 		return result;
 	}
 
 	if (build_context.cross_compiling && selected_target_metrics->metrics == &target_essence_amd64) {
-#ifdef GB_SYSTEM_UNIX
+#if defined(GB_SYSTEM_UNIX) 
 		result = system_exec_command_line_app("linker", "x86_64-essence-gcc \"%.*s.o\" -o \"%.*s\" %.*s %.*s",
-			LIT(output_base), LIT(output_base), LIT(build_context.link_flags), LIT(build_context.extra_linker_flags));
+			LIT(output_filename), LIT(output_filename), LIT(build_context.link_flags), LIT(build_context.extra_linker_flags));
 #else
 		gb_printf_err("Linking for cross compilation for this platform is not yet supported (%.*s %.*s)\n",
 			LIT(target_os_names[build_context.metrics.os]),
@@ -172,369 +164,360 @@ i32 linker_stage(lbGenerator *gen) {
 		build_context.keep_object_files = true;
 	} else {
 	#if defined(GB_SYSTEM_WINDOWS)
-		String section_name = str_lit("msvc-link");
-		if (build_context.use_lld) {
-			section_name = str_lit("lld-link");
-		}
-		timings_start_section(timings, section_name);
-
-		gbString lib_str = gb_string_make(heap_allocator(), "");
-		defer (gb_string_free(lib_str));
-
-		char const *output_ext = "exe";
-		gbString link_settings = gb_string_make_reserve(heap_allocator(), 256);
-		defer (gb_string_free(link_settings));
-
-
-		// NOTE(ic): It would be nice to extend this so that we could specify the Visual Studio version that we want instead of defaulting to the latest.
-		Find_Result_Utf8 find_result = find_visual_studio_and_windows_sdk_utf8();
+		bool is_windows = true;
+	#else
+		bool is_windows = false;
+	#endif
+	#if defined(GB_SYSTEM_OSX)
+		bool is_osx = true;
+	#else
+		bool is_osx = false;
+	#endif
 
-		if (find_result.windows_sdk_version == 0) {
-			gb_printf_err("Windows SDK not found.\n");
-			exit(1);
-		}
 
-		if (build_context.ignore_microsoft_magic) {
-			find_result = {};
-		}
+		if (is_windows) {
+			String section_name = str_lit("msvc-link");
+			if (build_context.use_lld) {
+				section_name = str_lit("lld-link");
+			}
+			timings_start_section(timings, section_name);
 
-		// Add library search paths.
-		if (find_result.vs_library_path.len > 0) {
-			GB_ASSERT(find_result.windows_sdk_um_library_path.len > 0);
-			GB_ASSERT(find_result.windows_sdk_ucrt_library_path.len > 0);
+			gbString lib_str = gb_string_make(heap_allocator(), "");
+			defer (gb_string_free(lib_str));
 
-			String path = {};
-			auto add_path = [&](String path) {
-				if (path[path.len-1] == '\\') {
-					path.len -= 1;
-				}
-				link_settings = gb_string_append_fmt(link_settings, " /LIBPATH:\"%.*s\"", LIT(path));
-			};
-			add_path(find_result.windows_sdk_um_library_path);
-			add_path(find_result.windows_sdk_ucrt_library_path);
-			add_path(find_result.vs_library_path);
-		}
+			gbString link_settings = gb_string_make_reserve(heap_allocator(), 256);
+			defer (gb_string_free(link_settings));
 
+			// Add library search paths.
+			if (build_context.build_paths[BuildPath_VS_LIB].basename.len > 0) {
+				String path = {};
+				auto add_path = [&](String path) {
+					if (path[path.len-1] == '\\') {
+						path.len -= 1;
+					}
+					link_settings = gb_string_append_fmt(link_settings, " /LIBPATH:\"%.*s\"", LIT(path));
+				};
+				add_path(build_context.build_paths[BuildPath_Win_SDK_UM_Lib].basename);
+				add_path(build_context.build_paths[BuildPath_Win_SDK_UCRT_Lib].basename);
+				add_path(build_context.build_paths[BuildPath_VS_LIB].basename);
+			}
 
-		StringSet libs = {};
-		string_set_init(&libs, heap_allocator(), 64);
-		defer (string_set_destroy(&libs));
 
-		StringSet asm_files = {};
-		string_set_init(&asm_files, heap_allocator(), 64);
-		defer (string_set_destroy(&asm_files));
+			StringSet libs = {};
+			string_set_init(&libs, heap_allocator(), 64);
+			defer (string_set_destroy(&libs));
+
+			StringSet asm_files = {};
+			string_set_init(&asm_files, heap_allocator(), 64);
+			defer (string_set_destroy(&asm_files));
+
+			for_array(j, gen->foreign_libraries) {
+				Entity *e = gen->foreign_libraries[j];
+				GB_ASSERT(e->kind == Entity_LibraryName);
+				for_array(i, e->LibraryName.paths) {
+					String lib = string_trim_whitespace(e->LibraryName.paths[i]);
+					// IMPORTANT NOTE(bill): calling `string_to_lower` here is not an issue because
+					// we will never uses these strings afterwards
+					string_to_lower(&lib);
+					if (lib.len == 0) {
+						continue;
+					}
 
-		for_array(j, gen->modules.entries) {
-			lbModule *m = gen->modules.entries[j].value;
-			for_array(i, m->foreign_library_paths) {
-				String lib = m->foreign_library_paths[i];
-				if (has_asm_extension(lib)) {
-					string_set_add(&asm_files, lib);
-				} else {
-					string_set_add(&libs, lib);
+					if (has_asm_extension(lib)) {
+						if (!string_set_update(&asm_files, lib)) {
+							String asm_file = asm_files.entries[i].value;
+							String obj_file = concatenate_strings(permanent_allocator(), asm_file, str_lit(".obj"));
+
+							result = system_exec_command_line_app("nasm",
+								"\"%.*s\\bin\\nasm\\windows\\nasm.exe\" \"%.*s\" "
+								"-f win64 "
+								"-o \"%.*s\" "
+								"%.*s "
+								"",
+								LIT(build_context.ODIN_ROOT), LIT(asm_file),
+								LIT(obj_file),
+								LIT(build_context.extra_assembler_flags)
+							);
+
+							if (result) {
+								return result;
+							}
+							array_add(&gen->output_object_paths, obj_file);
+						}
+					} else {
+						if (!string_set_update(&libs, lib)) {
+							lib_str = gb_string_append_fmt(lib_str, " \"%.*s\"", LIT(lib));
+						}
+					}
 				}
 			}
-		}
 
-		for_array(i, gen->default_module.foreign_library_paths) {
-			String lib = gen->default_module.foreign_library_paths[i];
-			if (has_asm_extension(lib)) {
-				string_set_add(&asm_files, lib);
+			if (build_context.build_mode == BuildMode_DynamicLibrary) {
+				link_settings = gb_string_append_fmt(link_settings, " /DLL");
 			} else {
-				string_set_add(&libs, lib);
+				link_settings = gb_string_append_fmt(link_settings, " /ENTRY:mainCRTStartup");
 			}
-		}
 
-		for_array(i, libs.entries) {
-			String lib = libs.entries[i].value;
-			lib_str = gb_string_append_fmt(lib_str, " \"%.*s\"", LIT(lib));
-		}
-
-
-		if (build_context.build_mode == BuildMode_DynamicLibrary) {
-			output_ext = "dll";
-			link_settings = gb_string_append_fmt(link_settings, " /DLL");
-		} else {
-			link_settings = gb_string_append_fmt(link_settings, " /ENTRY:mainCRTStartup");
-		}
-
-		if (build_context.pdb_filepath != "") {
-			link_settings = gb_string_append_fmt(link_settings, " /PDB:%.*s", LIT(build_context.pdb_filepath));
-		}
-
-		if (build_context.no_crt) {
-			link_settings = gb_string_append_fmt(link_settings, " /nodefaultlib");
-		} else {
-			link_settings = gb_string_append_fmt(link_settings, " /defaultlib:libcmt");
-		}
-
-		if (build_context.ODIN_DEBUG) {
-			link_settings = gb_string_append_fmt(link_settings, " /DEBUG");
-		}
+			if (build_context.pdb_filepath != "") {
+				String pdb_path = path_to_string(heap_allocator(), build_context.build_paths[BuildPath_PDB]);
+				link_settings = gb_string_append_fmt(link_settings, " /PDB:%.*s", LIT(pdb_path));
+			}
 
-		for_array(i, asm_files.entries) {
-			String asm_file = asm_files.entries[i].value;
-			String obj_file = concatenate_strings(permanent_allocator(), asm_file, str_lit(".obj"));
+			if (build_context.no_crt) {
+				link_settings = gb_string_append_fmt(link_settings, " /nodefaultlib");
+			} else {
+				link_settings = gb_string_append_fmt(link_settings, " /defaultlib:libcmt");
+			}
 
-			result = system_exec_command_line_app("nasm",
-				"\"%.*s\\bin\\nasm\\windows\\nasm.exe\" \"%.*s\" "
-				"-f win64 "
-				"-o \"%.*s\" "
-				"%.*s "
-				"",
-				LIT(build_context.ODIN_ROOT), LIT(asm_file),
-				LIT(obj_file),
-				LIT(build_context.extra_assembler_flags)
-			);
+			if (build_context.ODIN_DEBUG) {
+				link_settings = gb_string_append_fmt(link_settings, " /DEBUG");
+			}
 
-			if (result) {
-				return result;
+			gbString object_files = gb_string_make(heap_allocator(), "");
+			defer (gb_string_free(object_files));
+			for_array(i, gen->output_object_paths) {
+				String object_path = gen->output_object_paths[i];
+				object_files = gb_string_append_fmt(object_files, "\"%.*s\" ", LIT(object_path));
 			}
-			array_add(&gen->output_object_paths, obj_file);
-		}
 
-		gbString object_files = gb_string_make(heap_allocator(), "");
-		defer (gb_string_free(object_files));
-		for_array(i, gen->output_object_paths) {
-			String object_path = gen->output_object_paths[i];
-			object_files = gb_string_append_fmt(object_files, "\"%.*s\" ", LIT(object_path));
-		}
+			String vs_exe_path = path_to_string(heap_allocator(), build_context.build_paths[BuildPath_VS_EXE]);
+			defer (gb_free(heap_allocator(), vs_exe_path.text));
+
+			char const *subsystem_str = build_context.use_subsystem_windows ? "WINDOWS" : "CONSOLE";
+			if (!build_context.use_lld) { // msvc
+				if (build_context.has_resource) {
+					String rc_path  = path_to_string(heap_allocator(), build_context.build_paths[BuildPath_RC]);
+					String res_path = path_to_string(heap_allocator(), build_context.build_paths[BuildPath_RES]);
+					defer (gb_free(heap_allocator(), rc_path.text));
+					defer (gb_free(heap_allocator(), res_path.text));
+
+					result = system_exec_command_line_app("msvc-link",
+						"\"rc.exe\" /nologo /fo \"%.*s\" \"%.*s\"",
+						LIT(res_path),
+						LIT(rc_path)
+					);
+
+					if (result) {
+						return result;
+					}
 
-		char const *subsystem_str = build_context.use_subsystem_windows ? "WINDOWS" : "CONSOLE";
-		if (!build_context.use_lld) { // msvc
-			if (build_context.has_resource) {
-				result = system_exec_command_line_app("msvc-link",
-					"\"rc.exe\" /nologo /fo \"%.*s.res\" \"%.*s.rc\"",
-					LIT(output_base),
-					LIT(build_context.resource_filepath)
-				);
+					result = system_exec_command_line_app("msvc-link",
+						"\"%.*slink.exe\" %s \"%.*s\" -OUT:\"%.*s\" %s "
+						"/nologo /incremental:no /opt:ref /subsystem:%s "
+						" %.*s "
+						" %.*s "
+						" %s "
+						"",
+						LIT(vs_exe_path), object_files, LIT(res_path), LIT(output_filename),
+						link_settings,
+						subsystem_str,
+						LIT(build_context.link_flags),
+						LIT(build_context.extra_linker_flags),
+						lib_str
+					  );
+				} else {
+					result = system_exec_command_line_app("msvc-link",
+						"\"%.*slink.exe\" %s -OUT:\"%.*s\" %s "
+						"/nologo /incremental:no /opt:ref /subsystem:%s "
+						" %.*s "
+						" %.*s "
+						" %s "
+						"",
+						LIT(vs_exe_path), object_files, LIT(output_filename),
+						link_settings,
+						subsystem_str,
+						LIT(build_context.link_flags),
+						LIT(build_context.extra_linker_flags),
+						lib_str
+					);
+				}
 
 				if (result) {
 					return result;
 				}
 
-				result = system_exec_command_line_app("msvc-link",
-					"\"%.*slink.exe\" %s \"%.*s.res\" -OUT:\"%.*s.%s\" %s "
+			} else { // lld
+				result = system_exec_command_line_app("msvc-lld-link",
+					"\"%.*s\\bin\\lld-link\" %s -OUT:\"%.*s\" %s "
 					"/nologo /incremental:no /opt:ref /subsystem:%s "
 					" %.*s "
 					" %.*s "
 					" %s "
 					"",
-					LIT(find_result.vs_exe_path), object_files, LIT(output_base), LIT(output_base), output_ext,
-					link_settings,
-					subsystem_str,
-					LIT(build_context.link_flags),
-					LIT(build_context.extra_linker_flags),
-					lib_str
-				  );
-			} else {
-				result = system_exec_command_line_app("msvc-link",
-					"\"%.*slink.exe\" %s -OUT:\"%.*s.%s\" %s "
-					"/nologo /incremental:no /opt:ref /subsystem:%s "
-					" %.*s "
-					" %.*s "
-					" %s "
-					"",
-					LIT(find_result.vs_exe_path), object_files, LIT(output_base), output_ext,
+					LIT(build_context.ODIN_ROOT), object_files, LIT(output_filename),
 					link_settings,
 					subsystem_str,
 					LIT(build_context.link_flags),
 					LIT(build_context.extra_linker_flags),
 					lib_str
 				);
+
+				if (result) {
+					return result;
+				}
 			}
+		} else {
+			timings_start_section(timings, str_lit("ld-link"));
+
+			// NOTE(vassvik): get cwd, for used for local shared libs linking, since those have to be relative to the exe
+			char cwd[256];
+			#if !defined(GB_SYSTEM_WINDOWS)
+			getcwd(&cwd[0], 256);
+			#endif
+			//printf("%s\n", cwd);
+
+			// NOTE(vassvik): needs to add the root to the library search paths, so that the full filenames of the library
+			//                files can be passed with -l:
+			gbString lib_str = gb_string_make(heap_allocator(), "-L/");
+			defer (gb_string_free(lib_str));
+
+			StringSet libs = {};
+			string_set_init(&libs, heap_allocator(), 64);
+			defer (string_set_destroy(&libs));
+
+			for_array(j, gen->foreign_libraries) {
+				Entity *e = gen->foreign_libraries[j];
+				GB_ASSERT(e->kind == Entity_LibraryName);
+				for_array(i, e->LibraryName.paths) {
+					String lib = string_trim_whitespace(e->LibraryName.paths[i]);
+					if (lib.len == 0) {
+						continue;
+					}
+					if (string_set_update(&libs, lib)) {
+						continue;
+					}
 
-			if (result) {
-				return result;
+					// 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 (build_context.metrics.os == TargetOs_darwin) {
+						if (string_ends_with(lib, str_lit(".framework"))) {
+							// framework thingie
+							String lib_name = lib;
+							lib_name = remove_extension_from_path(lib_name);
+							lib_str = gb_string_append_fmt(lib_str, " -framework %.*s ", LIT(lib_name));
+						} else if (string_ends_with(lib, str_lit(".a")) || string_ends_with(lib, str_lit(".o")) || string_ends_with(lib, str_lit(".dylib"))) {
+							// For:
+							// object
+							// dynamic lib
+							// static libs, absolute full path relative to the file in which the lib was imported from
+							lib_str = gb_string_append_fmt(lib_str, " %.*s ", LIT(lib));
+						} else {
+							// 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 {
+						// 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")) || 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
+							// NOTE(vassvik): it is the user's responsibility to make sure the shared library files are visible
+							//                at runtime to the executable
+							lib_str = gb_string_append_fmt(lib_str, " -l:\"%s/%.*s\" ", cwd, LIT(lib));
+						} else {
+							// 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 { // lld
-			result = system_exec_command_line_app("msvc-lld-link",
-				"\"%.*s\\bin\\lld-link\" %s -OUT:\"%.*s.%s\" %s "
-				"/nologo /incremental:no /opt:ref /subsystem:%s "
-				" %.*s "
-				" %.*s "
-				" %s "
-				"",
-				LIT(build_context.ODIN_ROOT), object_files, LIT(output_base),output_ext,
-				link_settings,
-				subsystem_str,
-				LIT(build_context.link_flags),
-				LIT(build_context.extra_linker_flags),
-				lib_str
-			);
 
-			if (result) {
-				return result;
+			gbString object_files = gb_string_make(heap_allocator(), "");
+			defer (gb_string_free(object_files));
+			for_array(i, gen->output_object_paths) {
+				String object_path = gen->output_object_paths[i];
+				object_files = gb_string_append_fmt(object_files, "\"%.*s\" ", LIT(object_path));
 			}
-		}
-	#else
-		timings_start_section(timings, str_lit("ld-link"));
-
-		// NOTE(vassvik): get cwd, for used for local shared libs linking, since those have to be relative to the exe
-		char cwd[256];
-		getcwd(&cwd[0], 256);
-		//printf("%s\n", cwd);
 
-		// NOTE(vassvik): needs to add the root to the library search paths, so that the full filenames of the library
-		//                files can be passed with -l:
-		gbString lib_str = gb_string_make(heap_allocator(), "-L/");
-		defer (gb_string_free(lib_str));
+			gbString link_settings = gb_string_make_reserve(heap_allocator(), 32);
 
-		for_array(i, gen->default_module.foreign_library_paths) {
-			String lib = gen->default_module.foreign_library_paths[i];
+			if (build_context.no_crt) {
+				link_settings = gb_string_append_fmt(link_settings, "-nostdlib ");
+			}
 
-			// 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 (build_context.metrics.os == TargetOs_darwin) {
-				if (string_ends_with(lib, str_lit(".framework"))) {
-					// framework thingie
-					String lib_name = lib;
-					lib_name = remove_extension_from_path(lib_name);
-					lib_str = gb_string_append_fmt(lib_str, " -framework %.*s ", LIT(lib_name));
-				} else if (string_ends_with(lib, str_lit(".a")) || string_ends_with(lib, str_lit(".o")) || string_ends_with(lib, str_lit(".dylib"))) {
-					// For:
-					// object
-					// dynamic lib
-					// static libs, absolute full path relative to the file in which the lib was imported from
-					lib_str = gb_string_append_fmt(lib_str, " %.*s ", LIT(lib));
-				} else {
-					// 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 {
-				// 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")) || 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
-					// NOTE(vassvik): it is the user's responsibility to make sure the shared library files are visible
-					//                at runtimeto the executable
-					lib_str = gb_string_append_fmt(lib_str, " -l:\"%s/%.*s\" ", cwd, LIT(lib));
-				} else {
-					// dynamic or static system lib, just link regularly searching system library paths
-					lib_str = gb_string_append_fmt(lib_str, " -l%.*s ", LIT(lib));
-				}
+			// NOTE(dweiler): We use clang as a frontend for the linker as there are
+			// other runtime and compiler support libraries that need to be linked in
+			// very specific orders such as libgcc_s, ld-linux-so, unwind, etc.
+			// These are not always typically inside /lib, /lib64, or /usr versions
+			// of that, e.g libgcc.a is in /usr/lib/gcc/{version}, and can vary on
+			// the distribution of Linux even. The gcc or clang specs is the only
+			// reliable way to query this information to call ld directly.
+			if (build_context.build_mode == BuildMode_DynamicLibrary) {
+				// NOTE(dweiler): Let the frontend know we're building a shared library
+				// so it doesn't generate symbols which cannot be relocated.
+				link_settings = gb_string_appendc(link_settings, "-shared ");
+
+				// NOTE(dweiler): _odin_entry_point must be called at initialization
+				// time of the shared object, similarly, _odin_exit_point must be called
+				// at deinitialization. We can pass both -init and -fini to the linker by
+				// using a comma separated list of arguments to -Wl.
+				//
+				// This previously used ld but ld cannot actually build a shared library
+				// correctly this way since all the other dependencies provided implicitly
+				// by the compiler frontend are still needed and most of the command
+				// line arguments prepared previously are incompatible with ld.
+				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 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 ");
 			}
-		}
 
-		gbString object_files = gb_string_make(heap_allocator(), "");
-		defer (gb_string_free(object_files));
-		for_array(i, gen->output_object_paths) {
-			String object_path = gen->output_object_paths[i];
-			object_files = gb_string_append_fmt(object_files, "\"%.*s\" ", LIT(object_path));
-		}
-
-		// Unlike the Win32 linker code, the output_ext includes the dot, because
-		// typically executable files on *NIX systems don't have extensions.
-		String output_ext = {};
-		gbString link_settings = gb_string_make_reserve(heap_allocator(), 32);
-
-		if (build_context.no_crt) {
-			link_settings = gb_string_append_fmt(link_settings, "-nostdlib ");
-		}
-
-		// NOTE(dweiler): We use clang as a frontend for the linker as there are
-		// other runtime and compiler support libraries that need to be linked in
-		// very specific orders such as libgcc_s, ld-linux-so, unwind, etc.
-		// These are not always typically inside /lib, /lib64, or /usr versions
-		// of that, e.g libgcc.a is in /usr/lib/gcc/{version}, and can vary on
-		// the distribution of Linux even. The gcc or clang specs is the only
-		// reliable way to query this information to call ld directly.
-		if (build_context.build_mode == BuildMode_DynamicLibrary) {
-			// NOTE(dweiler): Let the frontend know we're building a shared library
-			// so it doesn't generate symbols which cannot be relocated.
-			link_settings = gb_string_appendc(link_settings, "-shared ");
-
-			// NOTE(dweiler): _odin_entry_point must be called at initialization
-			// time of the shared object, similarly, _odin_exit_point must be called
-			// at deinitialization. We can pass both -init and -fini to the linker by
-			// using a comma separated list of arguments to -Wl.
-			//
-			// This previously used ld but ld cannot actually build a shared library
-			// correctly this way since all the other dependencies provided implicitly
-			// by the compiler frontend are still needed and most of the command
-			// line arguments prepared previously are incompatible with ld.
-			//
-			// Shared libraries are .dylib on MacOS and .so on Linux.
+			gbString platform_lib_str = gb_string_make(heap_allocator(), "");
+			defer (gb_string_free(platform_lib_str));
 			if (build_context.metrics.os == TargetOs_darwin) {
-				output_ext = STR_LIT(".dylib");
+				platform_lib_str = gb_string_appendc(platform_lib_str, "-lSystem -lm -Wl,-syslibroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -L/usr/local/lib");
 			} else {
-				output_ext = STR_LIT(".so");
+				platform_lib_str = gb_string_appendc(platform_lib_str, "-lc -lm");
 			}
-			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 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) {
-			//NOTE(thebirk): We have a custom -out arguments, so we should use the extension from that
-			isize pos = string_extension_position(build_context.out_filepath);
-			if (pos > 0) {
-				output_ext = substring(build_context.out_filepath, pos, build_context.out_filepath.len);
-			}
-		}
-
-		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 ");
+			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 ");
 			}
-			// 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));
+			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);
+			link_command_line = gb_string_appendc(link_command_line, object_files);
+			link_command_line = gb_string_append_fmt(link_command_line, " -o \"%.*s\" ", LIT(output_filename));
+			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;
-		}
-
-	#if defined(GB_SYSTEM_OSX)
-		if (build_context.ODIN_DEBUG) {
-			// NOTE: macOS links DWARF symbols dynamically. Dsymutil will map the stubs in the exe
-			// to the symbols in the object file
-			result = system_exec_command_line_app("dsymutil",
-				"dsymutil %.*s%.*s", LIT(output_base), LIT(output_ext)
-			);
+			result = system_exec_command_line_app("ld-link", link_command_line);
 
 			if (result) {
 				return result;
 			}
-		}
-	#endif
 
-	#endif
+			if (is_osx && build_context.ODIN_DEBUG) {
+				// NOTE: macOS links DWARF symbols dynamically. Dsymutil will map the stubs in the exe
+				// to the symbols in the object file
+				result = system_exec_command_line_app("dsymutil", "dsymutil %.*s", LIT(output_filename));
+
+				if (result) {
+					return result;
+				}
+			}
+		}
 	}
 
 	return result;
@@ -666,6 +649,7 @@ enum BuildFlagKind {
 	BuildFlag_IgnoreWarnings,
 	BuildFlag_WarningsAsErrors,
 	BuildFlag_VerboseErrors,
+	BuildFlag_ErrorPosStyle,
 
 	// internal use only
 	BuildFlag_InternalIgnoreLazy,
@@ -829,6 +813,7 @@ bool parse_build_flags(Array<String> args) {
 	add_flag(&build_flags, BuildFlag_IgnoreWarnings,          str_lit("ignore-warnings"),           BuildFlagParam_None,    Command_all);
 	add_flag(&build_flags, BuildFlag_WarningsAsErrors,        str_lit("warnings-as-errors"),        BuildFlagParam_None,    Command_all);
 	add_flag(&build_flags, BuildFlag_VerboseErrors,           str_lit("verbose-errors"),            BuildFlagParam_None,    Command_all);
+	add_flag(&build_flags, BuildFlag_ErrorPosStyle,           str_lit("error-pos-style"),           BuildFlagParam_String,  Command_all);
 
 	add_flag(&build_flags, BuildFlag_InternalIgnoreLazy,      str_lit("internal-ignore-lazy"),      BuildFlagParam_None,    Command_all);
 
@@ -859,11 +844,19 @@ bool parse_build_flags(Array<String> args) {
 
 		String name = substring(flag, 1, flag.len);
 		isize end = 0;
+		bool have_equals = false;
 		for (; end < name.len; end++) {
 			if (name[end] == ':') break;
-			if (name[end] == '=') break; // IMPORTANT TODO(bill): DEPRECATE THIS!!!!
+			if (name[end] == '=') {
+				have_equals = true;
+				break;
+			}
 		}
 		name = substring(name, 0, end);
+		if (have_equals && name != "opt") {
+			gb_printf_err("`flag=value` has been deprecated and will be removed next release. Use `%.*s:` instead.\n", LIT(name));
+		}
+
 		String param = {};
 		if (end < flag.len-1) param = substring(flag, 2+end, flag.len);
 
@@ -937,35 +930,35 @@ bool parse_build_flags(Array<String> args) {
 						switch (bf.param_kind) {
 						case BuildFlagParam_None:
 							if (value.kind != ExactValue_Invalid) {
-								gb_printf_err("%.*s expected no value, got %.*s", LIT(name), LIT(param));
+								gb_printf_err("%.*s expected no value, got %.*s\n", LIT(name), LIT(param));
 								bad_flags = true;
 								ok = false;
 							}
 							break;
 						case BuildFlagParam_Boolean:
 							if (value.kind != ExactValue_Bool) {
-								gb_printf_err("%.*s expected a boolean, got %.*s", LIT(name), LIT(param));
+								gb_printf_err("%.*s expected a boolean, got %.*s\n", LIT(name), LIT(param));
 								bad_flags = true;
 								ok = false;
 							}
 							break;
 						case BuildFlagParam_Integer:
 							if (value.kind != ExactValue_Integer) {
-								gb_printf_err("%.*s expected an integer, got %.*s", LIT(name), LIT(param));
+								gb_printf_err("%.*s expected an integer, got %.*s\n", LIT(name), LIT(param));
 								bad_flags = true;
 								ok = false;
 							}
 							break;
 						case BuildFlagParam_Float:
 							if (value.kind != ExactValue_Float) {
-								gb_printf_err("%.*s expected a floating pointer number, got %.*s", LIT(name), LIT(param));
+								gb_printf_err("%.*s expected a floating pointer number, got %.*s\n", LIT(name), LIT(param));
 								bad_flags = true;
 								ok = false;
 							}
 							break;
 						case BuildFlagParam_String:
 							if (value.kind != ExactValue_String) {
-								gb_printf_err("%.*s expected a string, got %.*s", LIT(name), LIT(param));
+								gb_printf_err("%.*s expected a string, got %.*s\n", LIT(name), LIT(param));
 								bad_flags = true;
 								ok = false;
 							}
@@ -995,7 +988,20 @@ bool parse_build_flags(Array<String> args) {
 								bad_flags = true;
 								break;
 							}
+
 							build_context.optimization_level = cast(i32)big_int_to_i64(&value.value_integer);
+							if (build_context.optimization_level < 0 || build_context.optimization_level > 3) {
+								gb_printf_err("Invalid optimization level for -o:<integer>, got %d\n", build_context.optimization_level);
+								gb_printf_err("Valid optimization levels:\n");
+								gb_printf_err("\t0\n");
+								gb_printf_err("\t1\n");
+								gb_printf_err("\t2\n");
+								gb_printf_err("\t3\n");
+								bad_flags = true;
+							}
+
+							// Deprecation warning.
+							gb_printf_err("`-opt` has been deprecated and will be removed next release. Use `-o:minimal`, etc.\n");
 							break;
 						}
 						case BuildFlag_OptimizationMode: {
@@ -1508,6 +1514,20 @@ bool parse_build_flags(Array<String> args) {
 						case BuildFlag_VerboseErrors:
 							build_context.show_error_line = true;
 							break;
+
+						case BuildFlag_ErrorPosStyle:
+							GB_ASSERT(value.kind == ExactValue_String);
+
+							if (str_eq_ignore_case(value.value_string, str_lit("odin")) || str_eq_ignore_case(value.value_string, str_lit("default"))) {
+								build_context.ODIN_ERROR_POS_STYLE = ErrorPosStyle_Default;
+							} else if (str_eq_ignore_case(value.value_string, str_lit("unix"))) {
+								build_context.ODIN_ERROR_POS_STYLE = ErrorPosStyle_Unix;
+							} else {
+								gb_printf_err("-error-pos-style options are 'unix', 'odin' and 'default' (odin)\n");
+								bad_flags = true;
+							}
+							break;
+
 						case BuildFlag_InternalIgnoreLazy:
 							build_context.ignore_lazy = true;
 							break;
@@ -1526,6 +1546,10 @@ bool parse_build_flags(Array<String> args) {
 									gb_printf_err("Invalid -resource path %.*s, missing .rc\n", LIT(path));
 									bad_flags = true;
 									break;
+								} else if (!gb_file_exists((const char *)path.text)) {
+									gb_printf_err("Invalid -resource path %.*s, file does not exist.\n", LIT(path));
+									bad_flags = true;
+									break;
 								}
 								build_context.resource_filepath = substring(path, 0, string_extension_position(path));
 								build_context.has_resource = true;
@@ -1540,6 +1564,11 @@ bool parse_build_flags(Array<String> args) {
 							String path = value.value_string;
 							path = string_trim_whitespace(path);
 							if (is_build_flag_path_valid(path)) {
+								if (path_is_directory(path)) {
+									gb_printf_err("Invalid -pdb-name path. %.*s, is a directory.\n", LIT(path));
+									bad_flags = true;
+									break;									
+								}
 								// #if defined(GB_SYSTEM_WINDOWS)
 								// 	String ext = path_extension(path);
 								// 	if (ext != ".pdb") {
@@ -2666,6 +2695,8 @@ int main(int arg_count, char const **arg_ptr) {
 		return 1;
 	}
 
+	init_filename = copy_string(permanent_allocator(), init_filename);
+
 	if (init_filename == "-help" ||
 	    init_filename == "--help") {
 		build_context.show_help = true;
@@ -2688,6 +2719,12 @@ int main(int arg_count, char const **arg_ptr) {
 				gb_printf_err("Did you mean `%.*s %.*s %.*s -file`?\n", LIT(args[0]), LIT(command), LIT(init_filename));
 				gb_printf_err("The `-file` flag tells it to treat a file as a self-contained package.\n");
 				return 1;
+			} else {
+				String const ext = str_lit(".odin");
+				if (!string_ends_with(init_filename, ext)) {
+					gb_printf_err("Expected either a directory or a .odin file, got '%.*s'\n", LIT(init_filename));
+					return 1;
+				}
 			}
 		}
 	}
@@ -2709,13 +2746,24 @@ int main(int arg_count, char const **arg_ptr) {
 			get_fullpath_relative(heap_allocator(), odin_root_dir(), str_lit("shared")));
 	}
 
-
 	init_build_context(selected_target_metrics ? selected_target_metrics->metrics : nullptr);
 	// if (build_context.word_size == 4 && build_context.metrics.os != TargetOs_js) {
 	// 	print_usage_line(0, "%.*s 32-bit is not yet supported for this platform", LIT(args[0]));
 	// 	return 1;
 	// }
 
+	// Set and check build paths...
+	if (!init_build_paths(init_filename)) {
+		return 1;
+	}
+
+	if (build_context.show_debug_messages) {
+		for_array(i, build_context.build_paths) {
+			String build_path = path_to_string(heap_allocator(), build_context.build_paths[i]);
+			debugf("build_paths[%ld]: %.*s\n", i, LIT(build_path));
+		}		
+	}
+
 	init_global_thread_pool();
 	defer (thread_pool_destroy(&global_thread_pool));
 
@@ -2732,6 +2780,8 @@ int main(int arg_count, char const **arg_ptr) {
 	}
 	defer (destroy_parser(parser));
 
+	// TODO(jeroen): Remove the `init_filename` param.
+	// Let's put that on `build_context.build_paths[0]` instead.
 	if (parse_packages(parser, init_filename) != ParseFile_None) {
 		return 1;
 	}
@@ -2810,16 +2860,10 @@ int main(int arg_count, char const **arg_ptr) {
 	}
 
 	if (run_output) {
-	#if defined(GB_SYSTEM_WINDOWS)
-		return system_exec_command_line_app("odin run", "%.*s.exe %.*s", LIT(gen->output_base), LIT(run_args_string));
-	#else
-		//NOTE(thebirk): This whole thing is a little leaky
-		String output_ext = {};
-		String complete_path = concatenate_strings(permanent_allocator(), gen->output_base, output_ext);
-		complete_path = path_to_full_path(permanent_allocator(), complete_path);
-		return system_exec_command_line_app("odin run", "\"%.*s\" %.*s", LIT(complete_path), LIT(run_args_string));
-	#endif
-	}
+		String exe_name = path_to_string(heap_allocator(), build_context.build_paths[BuildPath_Output]);
+		defer (gb_free(heap_allocator(), exe_name.text));
 
+		return system_exec_command_line_app("odin run", "\"%.*s\" %.*s", LIT(exe_name), LIT(run_args_string));
+	}
 	return 0;
 }
diff --git a/src/parser.cpp b/src/parser.cpp
index 767119aa8..1f4093e5f 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -1160,11 +1160,10 @@ Ast *ast_package_decl(AstFile *f, Token token, Token name, CommentGroup *docs, C
 	return result;
 }
 
-Ast *ast_import_decl(AstFile *f, Token token, bool is_using, Token relpath, Token import_name,
+Ast *ast_import_decl(AstFile *f, Token token, Token relpath, Token import_name,
                      CommentGroup *docs, CommentGroup *comment) {
 	Ast *result = alloc_ast_node(f, Ast_ImportDecl);
 	result->ImportDecl.token       = token;
-	result->ImportDecl.is_using    = is_using;
 	result->ImportDecl.relpath     = relpath;
 	result->ImportDecl.import_name = import_name;
 	result->ImportDecl.docs        = docs;
@@ -4382,7 +4381,6 @@ Ast *parse_import_decl(AstFile *f, ImportDeclKind kind) {
 	CommentGroup *docs = f->lead_comment;
 	Token token = expect_token(f, Token_import);
 	Token import_name = {};
-	bool is_using = kind != ImportDecl_Standard;
 
 	switch (f->curr_token.kind) {
 	case Token_Ident:
@@ -4393,22 +4391,18 @@ Ast *parse_import_decl(AstFile *f, ImportDeclKind kind) {
 		break;
 	}
 
-	if (!is_using && is_blank_ident(import_name)) {
-		syntax_error(import_name, "Illegal import name: '_'");
-	}
-
 	Token file_path = expect_token_after(f, Token_String, "import");
 
 	Ast *s = nullptr;
 	if (f->curr_proc != nullptr) {
-		syntax_error(import_name, "You cannot use 'import' within a procedure. This must be done at the file scope");
+		syntax_error(import_name, "Cannot use 'import' within a procedure. This must be done at the file scope");
 		s = ast_bad_decl(f, import_name, file_path);
 	} else {
-		s = ast_import_decl(f, token, is_using, file_path, import_name, docs, f->line_comment);
+		s = ast_import_decl(f, token, file_path, import_name, docs, f->line_comment);
 		array_add(&f->imports, s);
 	}
 
-	if (is_using) {
+	if (kind != ImportDecl_Standard) {
 		syntax_error(import_name, "'using import' is not allowed, please use the import name explicitly");
 	}
 
@@ -5751,7 +5745,7 @@ ParseFileError parse_packages(Parser *p, String init_filename) {
 			}
 		}
 	}
-	
+
 
 	{ // Add these packages serially and then process them parallel
 		mutex_lock(&p->wait_mutex);
diff --git a/src/parser.hpp b/src/parser.hpp
index c7b4fd0d8..698ed7623 100644
--- a/src/parser.hpp
+++ b/src/parser.hpp
@@ -585,7 +585,6 @@ AST_KIND(_DeclBegin,      "", bool) \
 		Token    import_name;   \
 		CommentGroup *docs;     \
 		CommentGroup *comment;  \
-		bool     is_using;      \
 	}) \
 	AST_KIND(ForeignImportDecl, "foreign import declaration", struct { \
 		Token    token;           \
diff --git a/src/path.cpp b/src/path.cpp
new file mode 100644
index 000000000..6f83c39ea
--- /dev/null
+++ b/src/path.cpp
@@ -0,0 +1,394 @@
+/*

+	Path handling utilities.

+*/

+String remove_extension_from_path(String const &s) {

+	for (isize i = s.len-1; i >= 0; i--) {

+		if (s[i] == '.') {

+			return substring(s, 0, i);

+		}

+	}

+	return s;

+}

+

+String remove_directory_from_path(String const &s) {

+	isize len = 0;

+	for (isize i = s.len-1; i >= 0; i--) {

+		if (s[i] == '/' ||

+		    s[i] == '\\') {

+			break;

+		}

+		len += 1;

+	}

+	return substring(s, s.len-len, s.len);

+}

+

+bool path_is_directory(String path);

+

+String directory_from_path(String const &s) {

+	if (path_is_directory(s)) {

+		return s;

+	}

+

+	isize i = s.len-1;

+	for (; i >= 0; i--) {

+		if (s[i] == '/' ||

+		    s[i] == '\\') {

+			break;

+		}

+	}

+	if (i >= 0) {

+		return substring(s, 0, i);	

+	}

+	return substring(s, 0, 0);

+}

+

+#if defined(GB_SYSTEM_WINDOWS)

+	bool path_is_directory(String path) {

+		gbAllocator a = heap_allocator();

+		String16 wstr = string_to_string16(a, path);

+		defer (gb_free(a, wstr.text));

+

+		i32 attribs = GetFileAttributesW(wstr.text);

+		if (attribs < 0) return false;

+

+		return (attribs & FILE_ATTRIBUTE_DIRECTORY) != 0;

+	}

+

+#else

+	bool path_is_directory(String path) {

+		gbAllocator a = heap_allocator();

+		char *copy = cast(char *)copy_string(a, path).text;

+		defer (gb_free(a, copy));

+

+		struct stat s;

+		if (stat(copy, &s) == 0) {

+			return (s.st_mode & S_IFDIR) != 0;

+		}

+		return false;

+	}

+#endif

+

+

+String path_to_full_path(gbAllocator a, String path) {

+	gbAllocator ha = heap_allocator();

+	char *path_c = gb_alloc_str_len(ha, cast(char *)path.text, path.len);

+	defer (gb_free(ha, path_c));

+

+	char *fullpath = gb_path_get_full_name(a, path_c);

+	String res = string_trim_whitespace(make_string_c(fullpath));

+#if defined(GB_SYSTEM_WINDOWS)

+	for (isize i = 0; i < res.len; i++) {

+		if (res.text[i] == '\\') {

+			res.text[i] = '/';

+		}

+	}

+#endif

+	return copy_string(a, res);

+}

+

+struct Path {

+	String basename;

+	String name;

+	String ext;

+};

+

+// NOTE(Jeroen): Naively turns a Path into a string.

+String path_to_string(gbAllocator a, Path path) {

+	if (path.basename.len + path.name.len + path.ext.len == 0) {

+		return make_string(nullptr, 0);

+	}

+

+	isize len = path.basename.len + 1 + path.name.len + 1;

+	if (path.ext.len > 0) {

+		 len += path.ext.len + 1;

+	}

+

+	u8 *str = gb_alloc_array(a, u8, len);

+

+	isize i = 0;

+	gb_memmove(str+i, path.basename.text, path.basename.len); i += path.basename.len;

+	gb_memmove(str+i, "/", 1);                                i += 1;

+	gb_memmove(str+i, path.name.text,     path.name.len);     i += path.name.len;

+	if (path.ext.len > 0) {

+		gb_memmove(str+i, ".", 1);                            i += 1;

+		gb_memmove(str+i, path.ext.text,  path.ext.len);      i += path.ext.len;

+	}

+	str[i] = 0;

+

+	String res = make_string(str, i);

+	res        = string_trim_whitespace(res);

+	return res;

+}

+

+// NOTE(Jeroen): Naively turns a Path into a string, then normalizes it using `path_to_full_path`.

+String path_to_full_path(gbAllocator a, Path path) {

+	String temp = path_to_string(heap_allocator(), path);

+	defer (gb_free(heap_allocator(), temp.text));

+

+	return path_to_full_path(a, temp);

+}

+

+// NOTE(Jeroen): Takes a path like "odin" or "W:\Odin", turns it into a full path,

+// and then breaks it into its components to make a Path.

+Path path_from_string(gbAllocator a, String const &path) {

+	Path res = {};

+

+	if (path.len == 0) return res;

+

+	String fullpath = path_to_full_path(a, path);

+	defer (gb_free(heap_allocator(), fullpath.text));

+

+	res.basename = directory_from_path(fullpath);	

+	res.basename = copy_string(a, res.basename);

+

+	if (path_is_directory(fullpath)) {

+		// It's a directory. We don't need to tinker with the name and extension.

+		// It could have a superfluous trailing `/`. Remove it if so.

+		if (res.basename.len > 0 && res.basename.text[res.basename.len - 1] == '/') {

+			res.basename.len--;

+		}

+		return res;

+	}

+

+	isize name_start = (res.basename.len > 0) ? res.basename.len + 1 : res.basename.len;

+	res.name         = substring(fullpath, name_start, fullpath.len);

+	res.name         = remove_extension_from_path(res.name);

+	res.name         = copy_string(a, res.name);

+

+	res.ext          = path_extension(fullpath, false); // false says not to include the dot.

+	res.ext          = copy_string(a, res.ext);

+	return res;

+}

+

+// NOTE(Jeroen): Takes a path String and returns the last path element.

+String last_path_element(String const &path) {

+	isize count = 0;

+	u8 * start = (u8 *)(&path.text[path.len - 1]);

+	for (isize length = path.len; length > 0 && path.text[length - 1] != '/'; length--) {

+		count++;

+		start--;

+	}

+	if (count > 0) {

+		start++; // Advance past the `/` and return the substring.

+		String res = make_string(start, count);

+		return res;

+	}

+	// Must be a root path like `/` or `C:/`, return empty String.

+	return STR_LIT("");

+}

+

+bool path_is_directory(Path path) {

+	String path_string = path_to_full_path(heap_allocator(), path);

+	defer (gb_free(heap_allocator(), path_string.text));

+

+	return path_is_directory(path_string);

+}

+

+struct FileInfo {

+	String name;

+	String fullpath;

+	i64    size;

+	bool   is_dir;

+};

+

+enum ReadDirectoryError {

+	ReadDirectory_None,

+

+	ReadDirectory_InvalidPath,

+	ReadDirectory_NotExists,

+	ReadDirectory_Permission,

+	ReadDirectory_NotDir,

+	ReadDirectory_Empty,

+	ReadDirectory_Unknown,

+

+	ReadDirectory_COUNT,

+};

+

+i64 get_file_size(String path) {

+	char *c_str = alloc_cstring(heap_allocator(), path);

+	defer (gb_free(heap_allocator(), c_str));

+

+	gbFile f = {};

+	gbFileError err = gb_file_open(&f, c_str);

+	defer (gb_file_close(&f));

+	if (err != gbFileError_None) {

+		return -1;

+	}

+	return gb_file_size(&f);

+}

+

+

+#if defined(GB_SYSTEM_WINDOWS)

+ReadDirectoryError read_directory(String path, Array<FileInfo> *fi) {

+	GB_ASSERT(fi != nullptr);

+

+	gbAllocator a = heap_allocator();

+

+	while (path.len > 0) {

+		Rune end = path[path.len-1];

+		if (end == '/') {

+			path.len -= 1;

+		} else if (end == '\\') {

+			path.len -= 1;

+		} else {

+			break;

+		}

+	}

+

+	if (path.len == 0) {

+		return ReadDirectory_InvalidPath;

+	}

+	{

+		char *c_str = alloc_cstring(a, path);

+		defer (gb_free(a, c_str));

+

+		gbFile f = {};

+		gbFileError file_err = gb_file_open(&f, c_str);

+		defer (gb_file_close(&f));

+

+		switch (file_err) {

+		case gbFileError_Invalid:    return ReadDirectory_InvalidPath;

+		case gbFileError_NotExists:  return ReadDirectory_NotExists;

+		// case gbFileError_Permission: return ReadDirectory_Permission;

+		}

+	}

+

+	if (!path_is_directory(path)) {

+		return ReadDirectory_NotDir;

+	}

+

+

+	char *new_path = gb_alloc_array(a, char, path.len+3);

+	defer (gb_free(a, new_path));

+

+	gb_memmove(new_path, path.text, path.len);

+	gb_memmove(new_path+path.len, "/*", 2);

+	new_path[path.len+2] = 0;

+

+	String np = make_string(cast(u8 *)new_path, path.len+2);

+	String16 wstr = string_to_string16(a, np);

+	defer (gb_free(a, wstr.text));

+

+	WIN32_FIND_DATAW file_data = {};

+	HANDLE find_file = FindFirstFileW(wstr.text, &file_data);

+	if (find_file == INVALID_HANDLE_VALUE) {

+		return ReadDirectory_Unknown;

+	}

+	defer (FindClose(find_file));

+

+	array_init(fi, a, 0, 100);

+

+	do {

+		wchar_t *filename_w = file_data.cFileName;

+		i64 size = cast(i64)file_data.nFileSizeLow;

+		size |= (cast(i64)file_data.nFileSizeHigh) << 32;

+		String name = string16_to_string(a, make_string16_c(filename_w));

+		if (name == "." || name == "..") {

+			gb_free(a, name.text);

+			continue;

+		}

+

+		String filepath = {};

+		filepath.len = path.len+1+name.len;

+		filepath.text = gb_alloc_array(a, u8, filepath.len+1);

+		defer (gb_free(a, filepath.text));

+		gb_memmove(filepath.text, path.text, path.len);

+		gb_memmove(filepath.text+path.len, "/", 1);

+		gb_memmove(filepath.text+path.len+1, name.text, name.len);

+

+		FileInfo info = {};

+		info.name = name;

+		info.fullpath = path_to_full_path(a, filepath);

+		info.size = size;

+		info.is_dir = (file_data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;

+		array_add(fi, info);

+	} while (FindNextFileW(find_file, &file_data));

+

+	if (fi->count == 0) {

+		return ReadDirectory_Empty;

+	}

+

+	return ReadDirectory_None;

+}

+#elif defined(GB_SYSTEM_LINUX) || defined(GB_SYSTEM_OSX) || defined(GB_SYSTEM_FREEBSD) || defined(GB_SYSTEM_OPENBSD)

+

+#include <dirent.h>

+

+ReadDirectoryError read_directory(String path, Array<FileInfo> *fi) {

+	GB_ASSERT(fi != nullptr);

+

+	gbAllocator a = heap_allocator();

+

+	char *c_path = alloc_cstring(a, path);

+	defer (gb_free(a, c_path));

+

+	DIR *dir = opendir(c_path);

+	if (!dir) {

+		switch (errno) {

+		case ENOENT:

+			return ReadDirectory_NotExists;

+		case EACCES:

+			return ReadDirectory_Permission;

+		case ENOTDIR:

+			return ReadDirectory_NotDir;

+		default:

+			// ENOMEM: out of memory

+			// EMFILE: per-process limit on open fds reached

+			// ENFILE: system-wide limit on total open files reached

+			return ReadDirectory_Unknown;

+		}

+		GB_PANIC("unreachable");

+	}

+

+	array_init(fi, a, 0, 100);

+

+	for (;;) {

+		struct dirent *entry = readdir(dir);

+		if (entry == nullptr) {

+			break;

+		}

+

+		String name = make_string_c(entry->d_name);

+		if (name == "." || name == "..") {

+			continue;

+		}

+

+		String filepath = {};

+		filepath.len = path.len+1+name.len;

+		filepath.text = gb_alloc_array(a, u8, filepath.len+1);

+		defer (gb_free(a, filepath.text));

+		gb_memmove(filepath.text, path.text, path.len);

+		gb_memmove(filepath.text+path.len, "/", 1);

+		gb_memmove(filepath.text+path.len+1, name.text, name.len);

+		filepath.text[filepath.len] = 0;

+

+

+		struct stat dir_stat = {};

+

+		if (stat((char *)filepath.text, &dir_stat)) {

+			continue;

+		}

+

+		if (S_ISDIR(dir_stat.st_mode)) {

+			continue;

+		}

+

+		i64 size = dir_stat.st_size;

+

+		FileInfo info = {};

+		info.name = name;

+		info.fullpath = path_to_full_path(a, filepath);

+		info.size = size;

+		array_add(fi, info);

+	}

+

+	if (fi->count == 0) {

+		return ReadDirectory_Empty;

+	}

+

+	return ReadDirectory_None;

+}

+#else

+#error Implement read_directory

+#endif

+

diff --git a/src/ptr_set.cpp b/src/ptr_set.cpp
index b45997916..ffe48d69a 100644
--- a/src/ptr_set.cpp
+++ b/src/ptr_set.cpp
@@ -13,7 +13,7 @@ struct PtrSet {
 template <typename T> void ptr_set_init   (PtrSet<T> *s, gbAllocator a, isize capacity = 16);
 template <typename T> void ptr_set_destroy(PtrSet<T> *s);
 template <typename T> T    ptr_set_add    (PtrSet<T> *s, T ptr);
-template <typename T> bool ptr_set_update (PtrSet<T> *s, T ptr); // returns true if it previously existsed
+template <typename T> bool ptr_set_update (PtrSet<T> *s, T ptr); // returns true if it previously existed
 template <typename T> bool ptr_set_exists (PtrSet<T> *s, T ptr);
 template <typename T> void ptr_set_remove (PtrSet<T> *s, T ptr);
 template <typename T> void ptr_set_clear  (PtrSet<T> *s);
diff --git a/src/string.cpp b/src/string.cpp
index d3dbc6904..616761265 100644
--- a/src/string.cpp
+++ b/src/string.cpp
@@ -245,15 +245,14 @@ gb_inline isize string_extension_position(String const &str) {
 	return dot_pos;
 }
 
-String path_extension(String const &str) {
+String path_extension(String const &str, bool include_dot = true) {
 	isize pos = string_extension_position(str);
 	if (pos < 0) {
 		return make_string(nullptr, 0);
 	}
-	return substring(str, pos, str.len);
+	return substring(str, include_dot ? pos : pos + 1, str.len);
 }
 
-
 String string_trim_whitespace(String str) {
 	while (str.len > 0 && rune_is_whitespace(str[str.len-1])) {
 		str.len--;
@@ -299,38 +298,6 @@ String filename_from_path(String s) {
 	return make_string(nullptr, 0);
 }
 
-String remove_extension_from_path(String const &s) {
-	for (isize i = s.len-1; i >= 0; i--) {
-		if (s[i] == '.') {
-			return substring(s, 0, i);
-		}
-	}
-	return s;
-}
-
-String remove_directory_from_path(String const &s) {
-	isize len = 0;
-	for (isize i = s.len-1; i >= 0; i--) {
-		if (s[i] == '/' ||
-		    s[i] == '\\') {
-			break;
-		}
-		len += 1;
-	}
-	return substring(s, s.len-len, s.len);
-}
-
-String directory_from_path(String const &s) {
-	isize i = s.len-1;
-	for (; i >= 0; i--) {
-		if (s[i] == '/' ||
-		    s[i] == '\\') {
-			break;
-		}
-	}
-	return substring(s, 0, i);
-}
-
 String concatenate_strings(gbAllocator a, String const &x, String const &y) {
 	isize len = x.len+y.len;
 	u8 *data = gb_alloc_array(a, u8, len+1);
diff --git a/src/string_set.cpp b/src/string_set.cpp
index e27145289..746ad9529 100644
--- a/src/string_set.cpp
+++ b/src/string_set.cpp
@@ -13,6 +13,7 @@ struct StringSet {
 void string_set_init   (StringSet *s, gbAllocator a, isize capacity = 16);
 void string_set_destroy(StringSet *s);
 void string_set_add    (StringSet *s, String const &str);
+bool string_set_update (StringSet *s, String const &str); // returns true if it previously existed
 bool string_set_exists (StringSet *s, String const &str);
 void string_set_remove (StringSet *s, String const &str);
 void string_set_clear  (StringSet *s);
@@ -149,6 +150,34 @@ void string_set_add(StringSet *s, String const &str) {
 	}
 }
 
+bool string_set_update(StringSet *s, String const &str) {
+	bool exists = false;
+	MapIndex index;
+	MapFindResult fr;
+	StringHashKey key = string_hash_string(str);
+	if (s->hashes.count == 0) {
+		string_set_grow(s);
+	}
+	fr = string_set__find(s, key);
+	if (fr.entry_index != MAP_SENTINEL) {
+		index = fr.entry_index;
+		exists = true;
+	} else {
+		index = string_set__add_entry(s, key);
+		if (fr.entry_prev != MAP_SENTINEL) {
+			s->entries[fr.entry_prev].next = index;
+		} else {
+			s->hashes[fr.hash_index] = index;
+		}
+	}
+	s->entries[index].value = str;
+
+	if (string_set__full(s)) {
+		string_set_grow(s);
+	}
+	return exists;
+}
+
 
 void string_set__erase(StringSet *s, MapFindResult fr) {
 	MapFindResult last;