zig/src/link/Coff/lld.zig
2023-01-05 13:41:53 -05:00

604 lines
26 KiB
Zig

const std = @import("std");
const build_options = @import("build_options");
const allocPrint = std.fmt.allocPrint;
const assert = std.debug.assert;
const fs = std.fs;
const log = std.log.scoped(.link);
const mem = std.mem;
const mingw = @import("../../mingw.zig");
const link = @import("../../link.zig");
const lldMain = @import("../../main.zig").lldMain;
const trace = @import("../../tracy.zig").trace;
const Allocator = mem.Allocator;
const Cache = @import("../../Cache.zig");
const Coff = @import("../Coff.zig");
const Compilation = @import("../../Compilation.zig");
pub fn linkWithLLD(self: *Coff, comp: *Compilation, prog_node: *std.Progress.Node) !void {
const tracy = trace(@src());
defer tracy.end();
var arena_allocator = std.heap.ArenaAllocator.init(self.base.allocator);
defer arena_allocator.deinit();
const arena = arena_allocator.allocator();
const directory = self.base.options.emit.?.directory; // Just an alias to make it shorter to type.
const full_out_path = try directory.join(arena, &[_][]const u8{self.base.options.emit.?.sub_path});
// If there is no Zig code to compile, then we should skip flushing the output file because it
// will not be part of the linker line anyway.
const module_obj_path: ?[]const u8 = if (self.base.options.module != null) blk: {
try self.flushModule(comp, prog_node);
if (fs.path.dirname(full_out_path)) |dirname| {
break :blk try fs.path.join(arena, &.{ dirname, self.base.intermediary_basename.? });
} else {
break :blk self.base.intermediary_basename.?;
}
} else null;
var sub_prog_node = prog_node.start("LLD Link", 0);
sub_prog_node.activate();
sub_prog_node.context.refresh();
defer sub_prog_node.end();
const is_lib = self.base.options.output_mode == .Lib;
const is_dyn_lib = self.base.options.link_mode == .Dynamic and is_lib;
const is_exe_or_dyn_lib = is_dyn_lib or self.base.options.output_mode == .Exe;
const link_in_crt = self.base.options.link_libc and is_exe_or_dyn_lib;
const target = self.base.options.target;
// See link/Elf.zig for comments on how this mechanism works.
const id_symlink_basename = "lld.id";
var man: Cache.Manifest = undefined;
defer if (!self.base.options.disable_lld_caching) man.deinit();
var digest: [Cache.hex_digest_len]u8 = undefined;
if (!self.base.options.disable_lld_caching) {
man = comp.cache_parent.obtain();
self.base.releaseLock();
comptime assert(Compilation.link_hash_implementation_version == 7);
for (self.base.options.objects) |obj| {
_ = try man.addFile(obj.path, null);
man.hash.add(obj.must_link);
}
for (comp.c_object_table.keys()) |key| {
_ = try man.addFile(key.status.success.object_path, null);
}
try man.addOptionalFile(module_obj_path);
man.hash.addOptionalBytes(self.base.options.entry);
man.hash.addOptional(self.base.options.stack_size_override);
man.hash.addOptional(self.base.options.image_base_override);
man.hash.addListOfBytes(self.base.options.lib_dirs);
man.hash.add(self.base.options.skip_linker_dependencies);
if (self.base.options.link_libc) {
man.hash.add(self.base.options.libc_installation != null);
if (self.base.options.libc_installation) |libc_installation| {
man.hash.addBytes(libc_installation.crt_dir.?);
if (target.abi == .msvc) {
man.hash.addBytes(libc_installation.msvc_lib_dir.?);
man.hash.addBytes(libc_installation.kernel32_lib_dir.?);
}
}
}
link.hashAddSystemLibs(&man.hash, self.base.options.system_libs);
man.hash.addListOfBytes(self.base.options.force_undefined_symbols.keys());
man.hash.addOptional(self.base.options.subsystem);
man.hash.add(self.base.options.is_test);
man.hash.add(self.base.options.tsaware);
man.hash.add(self.base.options.nxcompat);
man.hash.add(self.base.options.dynamicbase);
// strip does not need to go into the linker hash because it is part of the hash namespace
man.hash.addOptional(self.base.options.major_subsystem_version);
man.hash.addOptional(self.base.options.minor_subsystem_version);
man.hash.addOptional(self.base.options.version);
try man.addOptionalFile(self.base.options.module_definition_file);
// We don't actually care whether it's a cache hit or miss; we just need the digest and the lock.
_ = try man.hit();
digest = man.final();
var prev_digest_buf: [digest.len]u8 = undefined;
const prev_digest: []u8 = Cache.readSmallFile(
directory.handle,
id_symlink_basename,
&prev_digest_buf,
) catch |err| blk: {
log.debug("COFF LLD new_digest={s} error: {s}", .{ std.fmt.fmtSliceHexLower(&digest), @errorName(err) });
// Handle this as a cache miss.
break :blk prev_digest_buf[0..0];
};
if (mem.eql(u8, prev_digest, &digest)) {
log.debug("COFF LLD digest={s} match - skipping invocation", .{std.fmt.fmtSliceHexLower(&digest)});
// Hot diggity dog! The output binary is already there.
self.base.lock = man.toOwnedLock();
return;
}
log.debug("COFF LLD prev_digest={s} new_digest={s}", .{ std.fmt.fmtSliceHexLower(prev_digest), std.fmt.fmtSliceHexLower(&digest) });
// We are about to change the output file to be different, so we invalidate the build hash now.
directory.handle.deleteFile(id_symlink_basename) catch |err| switch (err) {
error.FileNotFound => {},
else => |e| return e,
};
}
if (self.base.options.output_mode == .Obj) {
// LLD's COFF driver does not support the equivalent of `-r` so we do a simple file copy
// here. TODO: think carefully about how we can avoid this redundant operation when doing
// build-obj. See also the corresponding TODO in linkAsArchive.
const the_object_path = blk: {
if (self.base.options.objects.len != 0)
break :blk self.base.options.objects[0].path;
if (comp.c_object_table.count() != 0)
break :blk comp.c_object_table.keys()[0].status.success.object_path;
if (module_obj_path) |p|
break :blk p;
// TODO I think this is unreachable. Audit this situation when solving the above TODO
// regarding eliding redundant object -> object transformations.
return error.NoObjectsToLink;
};
// This can happen when using --enable-cache and using the stage1 backend. In this case
// we can skip the file copy.
if (!mem.eql(u8, the_object_path, full_out_path)) {
try fs.cwd().copyFile(the_object_path, fs.cwd(), full_out_path, .{});
}
} else {
// Create an LLD command line and invoke it.
var argv = std.ArrayList([]const u8).init(self.base.allocator);
defer argv.deinit();
// We will invoke ourselves as a child process to gain access to LLD.
// This is necessary because LLD does not behave properly as a library -
// it calls exit() and does not reset all global data between invocations.
const linker_command = "lld-link";
try argv.appendSlice(&[_][]const u8{ comp.self_exe_path.?, linker_command });
try argv.append("-ERRORLIMIT:0");
try argv.append("-NOLOGO");
if (!self.base.options.strip) {
try argv.append("-DEBUG");
const out_ext = std.fs.path.extension(full_out_path);
const out_pdb = self.base.options.pdb_out_path orelse try allocPrint(arena, "{s}.pdb", .{
full_out_path[0 .. full_out_path.len - out_ext.len],
});
try argv.append(try allocPrint(arena, "-PDB:{s}", .{out_pdb}));
try argv.append(try allocPrint(arena, "-PDBALTPATH:{s}", .{out_pdb}));
}
if (self.base.options.version) |version| {
try argv.append(try allocPrint(arena, "-VERSION:{}.{}", .{ version.major, version.minor }));
}
if (self.base.options.lto) {
switch (self.base.options.optimize_mode) {
.Debug => {},
.ReleaseSmall => try argv.append("-OPT:lldlto=2"),
.ReleaseFast, .ReleaseSafe => try argv.append("-OPT:lldlto=3"),
}
}
if (self.base.options.output_mode == .Exe) {
const stack_size = self.base.options.stack_size_override orelse 16777216;
try argv.append(try allocPrint(arena, "-STACK:{d}", .{stack_size}));
}
if (self.base.options.image_base_override) |image_base| {
try argv.append(try std.fmt.allocPrint(arena, "-BASE:{d}", .{image_base}));
}
if (target.cpu.arch == .x86) {
try argv.append("-MACHINE:X86");
} else if (target.cpu.arch == .x86_64) {
try argv.append("-MACHINE:X64");
} else if (target.cpu.arch.isARM()) {
if (target.cpu.arch.ptrBitWidth() == 32) {
try argv.append("-MACHINE:ARM");
} else {
try argv.append("-MACHINE:ARM64");
}
}
for (self.base.options.force_undefined_symbols.keys()) |symbol| {
try argv.append(try allocPrint(arena, "-INCLUDE:{s}", .{symbol}));
}
if (is_dyn_lib) {
try argv.append("-DLL");
}
if (self.base.options.entry) |entry| {
try argv.append(try allocPrint(arena, "-ENTRY:{s}", .{entry}));
}
if (self.base.options.tsaware) {
try argv.append("-tsaware");
}
if (self.base.options.nxcompat) {
try argv.append("-nxcompat");
}
if (self.base.options.dynamicbase) {
try argv.append("-dynamicbase");
}
try argv.append(try allocPrint(arena, "-OUT:{s}", .{full_out_path}));
if (self.base.options.implib_emit) |emit| {
const implib_out_path = try emit.directory.join(arena, &[_][]const u8{emit.sub_path});
try argv.append(try allocPrint(arena, "-IMPLIB:{s}", .{implib_out_path}));
}
if (self.base.options.link_libc) {
if (self.base.options.libc_installation) |libc_installation| {
try argv.append(try allocPrint(arena, "-LIBPATH:{s}", .{libc_installation.crt_dir.?}));
if (target.abi == .msvc) {
try argv.append(try allocPrint(arena, "-LIBPATH:{s}", .{libc_installation.msvc_lib_dir.?}));
try argv.append(try allocPrint(arena, "-LIBPATH:{s}", .{libc_installation.kernel32_lib_dir.?}));
}
}
}
for (self.base.options.lib_dirs) |lib_dir| {
try argv.append(try allocPrint(arena, "-LIBPATH:{s}", .{lib_dir}));
}
try argv.ensureUnusedCapacity(self.base.options.objects.len);
for (self.base.options.objects) |obj| {
if (obj.must_link) {
argv.appendAssumeCapacity(try allocPrint(arena, "-WHOLEARCHIVE:{s}", .{obj.path}));
} else {
argv.appendAssumeCapacity(obj.path);
}
}
for (comp.c_object_table.keys()) |key| {
try argv.append(key.status.success.object_path);
}
if (module_obj_path) |p| {
try argv.append(p);
}
if (self.base.options.module_definition_file) |def| {
try argv.append(try allocPrint(arena, "-DEF:{s}", .{def}));
}
const resolved_subsystem: ?std.Target.SubSystem = blk: {
if (self.base.options.subsystem) |explicit| break :blk explicit;
switch (target.os.tag) {
.windows => {
if (self.base.options.module) |module| {
if (module.stage1_flags.have_dllmain_crt_startup or is_dyn_lib)
break :blk null;
if (module.stage1_flags.have_c_main or self.base.options.is_test or
module.stage1_flags.have_winmain_crt_startup or
module.stage1_flags.have_wwinmain_crt_startup)
{
break :blk .Console;
}
if (module.stage1_flags.have_winmain or module.stage1_flags.have_wwinmain)
break :blk .Windows;
}
},
.uefi => break :blk .EfiApplication,
else => {},
}
break :blk null;
};
const Mode = enum { uefi, win32 };
const mode: Mode = mode: {
if (resolved_subsystem) |subsystem| {
const subsystem_suffix = ss: {
if (self.base.options.major_subsystem_version) |major| {
if (self.base.options.minor_subsystem_version) |minor| {
break :ss try allocPrint(arena, ",{d}.{d}", .{ major, minor });
} else {
break :ss try allocPrint(arena, ",{d}", .{major});
}
}
break :ss "";
};
switch (subsystem) {
.Console => {
try argv.append(try allocPrint(arena, "-SUBSYSTEM:console{s}", .{
subsystem_suffix,
}));
break :mode .win32;
},
.EfiApplication => {
try argv.append(try allocPrint(arena, "-SUBSYSTEM:efi_application{s}", .{
subsystem_suffix,
}));
break :mode .uefi;
},
.EfiBootServiceDriver => {
try argv.append(try allocPrint(arena, "-SUBSYSTEM:efi_boot_service_driver{s}", .{
subsystem_suffix,
}));
break :mode .uefi;
},
.EfiRom => {
try argv.append(try allocPrint(arena, "-SUBSYSTEM:efi_rom{s}", .{
subsystem_suffix,
}));
break :mode .uefi;
},
.EfiRuntimeDriver => {
try argv.append(try allocPrint(arena, "-SUBSYSTEM:efi_runtime_driver{s}", .{
subsystem_suffix,
}));
break :mode .uefi;
},
.Native => {
try argv.append(try allocPrint(arena, "-SUBSYSTEM:native{s}", .{
subsystem_suffix,
}));
break :mode .win32;
},
.Posix => {
try argv.append(try allocPrint(arena, "-SUBSYSTEM:posix{s}", .{
subsystem_suffix,
}));
break :mode .win32;
},
.Windows => {
try argv.append(try allocPrint(arena, "-SUBSYSTEM:windows{s}", .{
subsystem_suffix,
}));
break :mode .win32;
},
}
} else if (target.os.tag == .uefi) {
break :mode .uefi;
} else {
break :mode .win32;
}
};
switch (mode) {
.uefi => try argv.appendSlice(&[_][]const u8{
"-BASE:0",
"-ENTRY:EfiMain",
"-OPT:REF",
"-SAFESEH:NO",
"-MERGE:.rdata=.data",
"-NODEFAULTLIB",
"-SECTION:.xdata,D",
}),
.win32 => {
if (link_in_crt) {
if (target.abi.isGnu()) {
try argv.append("-lldmingw");
if (target.cpu.arch == .x86) {
try argv.append("-ALTERNATENAME:__image_base__=___ImageBase");
} else {
try argv.append("-ALTERNATENAME:__image_base__=__ImageBase");
}
if (is_dyn_lib) {
try argv.append(try comp.get_libc_crt_file(arena, "dllcrt2.obj"));
if (target.cpu.arch == .x86) {
try argv.append("-ALTERNATENAME:__DllMainCRTStartup@12=_DllMainCRTStartup@12");
} else {
try argv.append("-ALTERNATENAME:_DllMainCRTStartup=DllMainCRTStartup");
}
} else {
try argv.append(try comp.get_libc_crt_file(arena, "crt2.obj"));
}
try argv.append(try comp.get_libc_crt_file(arena, "mingw32.lib"));
try argv.append(try comp.get_libc_crt_file(arena, "mingwex.lib"));
try argv.append(try comp.get_libc_crt_file(arena, "msvcrt-os.lib"));
for (mingw.always_link_libs) |name| {
if (!self.base.options.system_libs.contains(name)) {
const lib_basename = try allocPrint(arena, "{s}.lib", .{name});
try argv.append(try comp.get_libc_crt_file(arena, lib_basename));
}
}
} else {
const lib_str = switch (self.base.options.link_mode) {
.Dynamic => "",
.Static => "lib",
};
const d_str = switch (self.base.options.optimize_mode) {
.Debug => "d",
else => "",
};
switch (self.base.options.link_mode) {
.Static => try argv.append(try allocPrint(arena, "libcmt{s}.lib", .{d_str})),
.Dynamic => try argv.append(try allocPrint(arena, "msvcrt{s}.lib", .{d_str})),
}
try argv.append(try allocPrint(arena, "{s}vcruntime{s}.lib", .{ lib_str, d_str }));
try argv.append(try allocPrint(arena, "{s}ucrt{s}.lib", .{ lib_str, d_str }));
//Visual C++ 2015 Conformance Changes
//https://msdn.microsoft.com/en-us/library/bb531344.aspx
try argv.append("legacy_stdio_definitions.lib");
// msvcrt depends on kernel32 and ntdll
try argv.append("kernel32.lib");
try argv.append("ntdll.lib");
}
} else {
try argv.append("-NODEFAULTLIB");
if (!is_lib and self.base.options.entry == null) {
if (self.base.options.module) |module| {
if (module.stage1_flags.have_winmain_crt_startup) {
try argv.append("-ENTRY:WinMainCRTStartup");
} else {
try argv.append("-ENTRY:wWinMainCRTStartup");
}
} else {
try argv.append("-ENTRY:wWinMainCRTStartup");
}
}
}
},
}
// libc++ dep
if (self.base.options.link_libcpp) {
try argv.append(comp.libcxxabi_static_lib.?.full_object_path);
try argv.append(comp.libcxx_static_lib.?.full_object_path);
}
// libunwind dep
if (self.base.options.link_libunwind) {
try argv.append(comp.libunwind_static_lib.?.full_object_path);
}
if (is_exe_or_dyn_lib and !self.base.options.skip_linker_dependencies) {
if (!self.base.options.link_libc) {
if (comp.libc_static_lib) |lib| {
try argv.append(lib.full_object_path);
}
}
// MinGW doesn't provide libssp symbols
if (target.abi.isGnu()) {
if (comp.libssp_static_lib) |lib| {
try argv.append(lib.full_object_path);
}
}
// MSVC compiler_rt is missing some stuff, so we build it unconditionally but
// and rely on weak linkage to allow MSVC compiler_rt functions to override ours.
if (comp.compiler_rt_lib) |lib| {
try argv.append(lib.full_object_path);
}
}
try argv.ensureUnusedCapacity(self.base.options.system_libs.count());
for (self.base.options.system_libs.keys()) |key| {
const lib_basename = try allocPrint(arena, "{s}.lib", .{key});
if (comp.crt_files.get(lib_basename)) |crt_file| {
argv.appendAssumeCapacity(crt_file.full_object_path);
continue;
}
if (try findLib(arena, lib_basename, self.base.options.lib_dirs)) |full_path| {
argv.appendAssumeCapacity(full_path);
continue;
}
if (target.abi.isGnu()) {
const fallback_name = try allocPrint(arena, "lib{s}.dll.a", .{key});
if (try findLib(arena, fallback_name, self.base.options.lib_dirs)) |full_path| {
argv.appendAssumeCapacity(full_path);
continue;
}
}
if (target.abi == .msvc) {
argv.appendAssumeCapacity(lib_basename);
continue;
}
log.err("DLL import library for -l{s} not found", .{key});
return error.DllImportLibraryNotFound;
}
if (self.base.options.verbose_link) {
// Skip over our own name so that the LLD linker name is the first argv item.
Compilation.dump_argv(argv.items[1..]);
}
if (std.process.can_spawn) {
// If possible, we run LLD as a child process because it does not always
// behave properly as a library, unfortunately.
// https://github.com/ziglang/zig/issues/3825
var child = std.ChildProcess.init(argv.items, arena);
if (comp.clang_passthrough_mode) {
child.stdin_behavior = .Inherit;
child.stdout_behavior = .Inherit;
child.stderr_behavior = .Inherit;
const term = child.spawnAndWait() catch |err| {
log.err("unable to spawn {s}: {s}", .{ argv.items[0], @errorName(err) });
return error.UnableToSpawnSelf;
};
switch (term) {
.Exited => |code| {
if (code != 0) {
std.process.exit(code);
}
},
else => std.process.abort(),
}
} else {
child.stdin_behavior = .Ignore;
child.stdout_behavior = .Ignore;
child.stderr_behavior = .Pipe;
try child.spawn();
const stderr = try child.stderr.?.reader().readAllAlloc(arena, 10 * 1024 * 1024);
const term = child.wait() catch |err| {
log.err("unable to spawn {s}: {s}", .{ argv.items[0], @errorName(err) });
return error.UnableToSpawnSelf;
};
switch (term) {
.Exited => |code| {
if (code != 0) {
comp.lockAndParseLldStderr(linker_command, stderr);
return error.LLDReportedFailure;
}
},
else => {
log.err("{s} terminated with stderr:\n{s}", .{ argv.items[0], stderr });
return error.LLDCrashed;
},
}
if (stderr.len != 0) {
log.warn("unexpected LLD stderr:\n{s}", .{stderr});
}
}
} else {
const exit_code = try lldMain(arena, argv.items, false);
if (exit_code != 0) {
if (comp.clang_passthrough_mode) {
std.process.exit(exit_code);
} else {
return error.LLDReportedFailure;
}
}
}
}
if (!self.base.options.disable_lld_caching) {
// Update the file with the digest. If it fails we can continue; it only
// means that the next invocation will have an unnecessary cache miss.
Cache.writeSmallFile(directory.handle, id_symlink_basename, &digest) catch |err| {
log.warn("failed to save linking hash digest file: {s}", .{@errorName(err)});
};
// Again failure here only means an unnecessary cache miss.
man.writeManifest() catch |err| {
log.warn("failed to write cache manifest when linking: {s}", .{@errorName(err)});
};
// We hang on to this lock so that the output file path can be used without
// other processes clobbering it.
self.base.lock = man.toOwnedLock();
}
}
fn findLib(arena: Allocator, name: []const u8, lib_dirs: []const []const u8) !?[]const u8 {
for (lib_dirs) |lib_dir| {
const full_path = try fs.path.join(arena, &.{ lib_dir, name });
fs.cwd().access(full_path, .{}) catch |err| switch (err) {
error.FileNotFound => continue,
else => |e| return e,
};
return full_path;
}
return null;
}