Move linker code into separate file

1 files changed, 427 insertions, 0 deletions

diff --git a/src/linker.cpp b/src/linker.cpp
new file mode 100644
index 000000000..dc6e072d1
--- /dev/null
+++ b/src/linker.cpp
@@ -0,0 +1,427 @@
+struct LinkerData {
+	BlockingMutex foreign_mutex;
+	PtrSet<Entity *> foreign_libraries_set;
+	Array<Entity *>  foreign_libraries;
+
+	Array<String> output_object_paths;
+	Array<String> output_temp_paths;
+	String   output_base;
+	String   output_name;
+};
+
+gb_internal i32 system_exec_command_line_app(char const *name, char const *fmt, ...);
+
+gb_internal i32 linker_stage(LinkerData *gen) {
+	i32 result = 0;
+	Timings *timings = &global_timings;
+
+	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.o\" -o \"%.*s\" %.*s %.*s",
+			LIT(build_context.ODIN_ROOT),
+			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.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) {
+#if defined(GB_SYSTEM_UNIX)
+		result = system_exec_command_line_app("linker", "x86_64-essence-gcc \"%.*s.o\" -o \"%.*s\" %.*s %.*s",
+			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]),
+			LIT(target_arch_names[build_context.metrics.arch])
+		);
+#endif
+	} else if (build_context.cross_compiling && build_context.different_os) {
+		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]),
+			LIT(target_arch_names[build_context.metrics.arch])
+		);
+		build_context.keep_object_files = true;
+	} else {
+	#if defined(GB_SYSTEM_WINDOWS)
+		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 (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);
+
+			gbString lib_str = gb_string_make(heap_allocator(), "");
+			defer (gb_string_free(lib_str));
+
+			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, 64);
+			defer (string_set_destroy(&libs));
+
+			StringSet asm_files = {};
+			string_set_init(&asm_files, 64);
+			defer (string_set_destroy(&asm_files));
+
+			for (Entity *e : gen->foreign_libraries) {
+				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;
+					}
+
+					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 (Entity *e : gen->foreign_libraries) {
+				GB_ASSERT(e->kind == Entity_LibraryName);
+				if (e->LibraryName.extra_linker_flags.len != 0) {
+					lib_str = gb_string_append_fmt(lib_str, " %.*s", LIT(e->LibraryName.extra_linker_flags));
+				}
+			}
+
+			if (build_context.build_mode == BuildMode_DynamicLibrary) {
+				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 != "") {
+				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));
+			}
+
+			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");
+			}
+
+			gbString object_files = gb_string_make(heap_allocator(), "");
+			defer (gb_string_free(object_files));
+			for (String const &object_path : gen->output_object_paths) {
+				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));
+
+			String windows_sdk_bin_path = path_to_string(heap_allocator(), build_context.build_paths[BuildPath_Win_SDK_Bin_Path]);
+			defer (gb_free(heap_allocator(), windows_sdk_bin_path.text));
+
+			char const *subsystem_str = build_context.use_subsystem_windows ? "WINDOWS" : "CONSOLE";
+			if (!build_context.use_lld) { // msvc
+				String res_path = {};
+				defer (gb_free(heap_allocator(), res_path.text));
+				if (build_context.has_resource) {
+					String temp_res_path = path_to_string(heap_allocator(), build_context.build_paths[BuildPath_RES]);
+					res_path = concatenate3_strings(heap_allocator(), str_lit("\""), temp_res_path, str_lit("\""));
+					gb_free(heap_allocator(), temp_res_path.text);
+
+					String rc_path  = path_to_string(heap_allocator(), build_context.build_paths[BuildPath_RC]);
+					defer (gb_free(heap_allocator(), rc_path.text));
+
+					result = system_exec_command_line_app("msvc-link",
+						"\"%.*src.exe\" /nologo /fo \"%.*s\" \"%.*s\"",
+						LIT(windows_sdk_bin_path),
+						LIT(res_path),
+						LIT(rc_path)
+					);
+
+					if (result) {
+						return result;
+					}
+				}
+
+				switch (build_context.build_mode) {
+				case BuildMode_Executable:
+					link_settings = gb_string_append_fmt(link_settings, " /NOIMPLIB /NOEXP");
+					break;
+				}
+
+				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
+				);
+				if (result) {
+					return result;
+				}
+			} 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(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, 64);
+			defer (string_set_destroy(&libs));
+
+			for (Entity *e : gen->foreign_libraries) {
+				GB_ASSERT(e->kind == Entity_LibraryName);
+				for (String lib : e->LibraryName.paths) {
+					lib = string_trim_whitespace(lib);
+					if (lib.len == 0) {
+						continue;
+					}
+					if (string_set_update(&libs, lib)) {
+						continue;
+					}
+
+					// 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));
+						}
+					}
+				}
+			}
+
+			for (Entity *e : gen->foreign_libraries) {
+				GB_ASSERT(e->kind == Entity_LibraryName);
+				if (e->LibraryName.extra_linker_flags.len != 0) {
+					lib_str = gb_string_append_fmt(lib_str, " %.*s", LIT(e->LibraryName.extra_linker_flags));
+				}
+			}
+
+			gbString object_files = gb_string_make(heap_allocator(), "");
+			defer (gb_string_free(object_files));
+			for (String object_path : gen->output_object_paths) {
+				object_files = gb_string_append_fmt(object_files, "\"%.*s\" ", LIT(object_path));
+			}
+
+			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.
+				if (build_context.metrics.os == TargetOs_darwin) {
+					link_settings = gb_string_appendc(link_settings, "-Wl,-init,'__odin_entry_point' ");
+					// NOTE(weshardee): __odin_exit_point should also be added, but -fini
+					// does not exist on MacOS
+				} else {
+					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 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.
+				if (build_context.minimum_os_version_string.len) {
+					link_settings = gb_string_append_fmt(link_settings, " -mmacosx-version-min=%.*s ", LIT(build_context.minimum_os_version_string));
+				} else 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=10.12.0 ");
+				}
+				// This points the linker to where the entry point is
+				link_settings = gb_string_appendc(link_settings, " -e _main ");
+			}
+
+			gbString link_command_line = gb_string_make(heap_allocator(), "clang -Wno-unused-command-line-argument ");
+			defer (gb_string_free(link_command_line));
+
+			link_command_line = gb_string_appendc(link_command_line, object_files);
+			link_command_line = gb_string_append_fmt(link_command_line, " -o \"%.*s\" ", 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 (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;
+}