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stage2: add --sysroot link option

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This feature is necessary for cross-compiling code that dynamically
links system libraries, at least with the current feature set of lld.
This commit is contained in:
Isaac Freund
2021-06-21 22:45:43 +02:00
parent 3e4f3a1924
commit 16228e87d6
5 changed files with 46 additions and 24 deletions
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42
src/Compilation.zig
View File

@@ -612,6 +612,7 @@ pub const InitOptions = struct {
output_mode: std.builtin.OutputMode,
thread_pool: *ThreadPool,
dynamic_linker: ?[]const u8 = null,
sysroot: ?[]const u8 = null,
/// `null` means to not emit a binary file.
emit_bin: ?EmitLoc,
/// `null` means to not emit a C header file.
@@ -868,25 +869,32 @@ pub fn create(gpa: *Allocator, options: InitOptions) !*Compilation {
break :blk false;
};
const DarwinOptions = struct {
syslibroot: ?[]const u8 = null,
system_linker_hack: bool = false,
const darwin_can_use_system_linker_and_sdk =
// comptime conditions
((build_options.have_llvm and comptime std.Target.current.isDarwin()) and
// runtime conditions
(use_lld and std.builtin.os.tag == .macos and options.target.isDarwin()));
const darwin_system_linker_hack = blk: {
if (darwin_can_use_system_linker_and_sdk) {
break :blk std.os.getenv("ZIG_SYSTEM_LINKER_HACK") != null;
} else {
break :blk false;
}
};
const darwin_options: DarwinOptions = if (build_options.have_llvm and comptime std.Target.current.isDarwin()) outer: {
const opts: DarwinOptions = if (use_lld and std.builtin.os.tag == .macos and options.target.isDarwin()) inner: {
const sysroot = blk: {
if (options.sysroot) |sysroot| {
break :blk sysroot;
} else if (darwin_can_use_system_linker_and_sdk) {
// TODO Revisit this targeting versions lower than macOS 11 when LLVM 12 is out.
// See https://github.com/ziglang/zig/issues/6996
const at_least_big_sur = options.target.os.getVersionRange().semver.min.major >= 11;
const syslibroot = if (at_least_big_sur) try std.zig.system.getSDKPath(arena) else null;
const system_linker_hack = std.os.getenv("ZIG_SYSTEM_LINKER_HACK") != null;
break :inner .{
.syslibroot = syslibroot,
.system_linker_hack = system_linker_hack,
};
} else .{};
break :outer opts;
} else .{};
break :blk if (at_least_big_sur) try std.zig.system.getSDKPath(arena) else null;
} else {
break :blk null;
}
};
const lto = blk: {
if (options.want_lto) |explicit| {
@@ -897,7 +905,7 @@ pub fn create(gpa: *Allocator, options: InitOptions) !*Compilation {
break :blk false;
} else if (options.c_source_files.len == 0) {
break :blk false;
} else if (darwin_options.system_linker_hack) {
} else if (darwin_system_linker_hack) {
break :blk false;
} else switch (options.output_mode) {
.Lib, .Obj => break :blk false,
@@ -1273,13 +1281,14 @@ pub fn create(gpa: *Allocator, options: InitOptions) !*Compilation {
.module = module,
.target = options.target,
.dynamic_linker = options.dynamic_linker,
.sysroot = sysroot,
.output_mode = options.output_mode,
.link_mode = link_mode,
.object_format = ofmt,
.optimize_mode = options.optimize_mode,
.use_lld = use_lld,
.use_llvm = use_llvm,
.system_linker_hack = darwin_options.system_linker_hack,
.system_linker_hack = darwin_system_linker_hack,
.link_libc = link_libc,
.link_libcpp = link_libcpp,
.link_libunwind = link_libunwind,
@@ -1287,7 +1296,6 @@ pub fn create(gpa: *Allocator, options: InitOptions) !*Compilation {
.frameworks = options.frameworks,
.framework_dirs = options.framework_dirs,
.system_libs = system_libs,
.syslibroot = darwin_options.syslibroot,
.lib_dirs = options.lib_dirs,
.rpath_list = options.rpath_list,
.strip = strip,

4
src/link.zig
View File

@@ -37,6 +37,8 @@ pub const Options = struct {
/// Not every Compilation compiles .zig code! For example you could do `zig build-exe foo.o`.
module: ?*Module,
dynamic_linker: ?[]const u8,
/// The root path for the dynamic linker and system libraries (as well as frameworks on Darwin)
sysroot: ?[]const u8,
/// Used for calculating how much space to reserve for symbols in case the binary file
/// does not already have a symbol table.
symbol_count_hint: u64 = 32,
@@ -103,8 +105,6 @@ pub const Options = struct {
llvm_cpu_features: ?[*:0]const u8,
/// Extra args passed directly to LLD. Ignored when not linking with LLD.
extra_lld_args: []const []const u8,
/// Darwin-only. Set the root path to the system libraries and frameworks.
syslibroot: ?[]const u8,
objects: []const []const u8,
framework_dirs: []const []const u8,

5
src/link/Elf.zig
View File

@@ -1354,6 +1354,7 @@ fn linkWithLLD(self: *Elf, comp: *Compilation) !void {
man.hash.add(allow_shlib_undefined);
man.hash.add(self.base.options.bind_global_refs_locally);
man.hash.add(self.base.options.tsan);
man.hash.addOptionalBytes(self.base.options.sysroot);
// We don't actually care whether it's a cache hit or miss; we just need the digest and the lock.
_ = try man.hit();
@@ -1423,6 +1424,10 @@ fn linkWithLLD(self: *Elf, comp: *Compilation) !void {
try argv.append("-error-limit=0");
if (self.base.options.sysroot) |sysroot| {
try argv.append(try std.fmt.allocPrint(arena, "--sysroot={s}", .{sysroot}));
}
if (self.base.options.lto) {
switch (self.base.options.optimize_mode) {
.Debug => {},

8
src/link/MachO.zig
View File

@@ -590,7 +590,7 @@ fn linkWithLLD(self: *MachO, comp: *Compilation) !void {
man.hash.add(allow_shlib_undefined);
man.hash.add(self.base.options.bind_global_refs_locally);
man.hash.add(self.base.options.system_linker_hack);
man.hash.addOptionalBytes(self.base.options.syslibroot);
man.hash.addOptionalBytes(self.base.options.sysroot);
// We don't actually care whether it's a cache hit or miss; we just need the digest and the lock.
_ = try man.hit();
@@ -720,7 +720,7 @@ fn linkWithLLD(self: *MachO, comp: *Compilation) !void {
for (self.base.options.lib_dirs) |path| {
if (fs.path.isAbsolute(path)) {
var candidates = std.ArrayList([]const u8).init(arena);
if (self.base.options.syslibroot) |syslibroot| {
if (self.base.options.sysroot) |syslibroot| {
const full_path = try fs.path.join(arena, &[_][]const u8{ syslibroot, path });
try candidates.append(full_path);
}
@@ -813,7 +813,7 @@ fn linkWithLLD(self: *MachO, comp: *Compilation) !void {
try argv.append("zig");
try argv.append("ld");
if (self.base.options.syslibroot) |syslibroot| {
if (self.base.options.sysroot) |syslibroot| {
try argv.append("-syslibroot");
try argv.append(syslibroot);
}
@@ -959,7 +959,7 @@ fn linkWithLLD(self: *MachO, comp: *Compilation) !void {
}
}
if (self.base.options.syslibroot) |dir| {
if (self.base.options.sysroot) |dir| {
try argv.append("-syslibroot");
try argv.append(dir);
}

11
src/main.zig
View File

@@ -377,6 +377,7 @@ const usage_build_generic =
\\ -T[script], --script [script] Use a custom linker script
\\ --version-script [path] Provide a version .map file
\\ --dynamic-linker [path] Set the dynamic interpreter path (usually ld.so)
\\ --sysroot [path] Set the system root directory (usually /)
\\ --version [ver] Dynamic library semver
\\ -fsoname[=name] (Linux) Override the default SONAME value
\\ -fno-soname (Linux) Disable emitting a SONAME
@@ -602,6 +603,7 @@ fn buildOutputType(
var link_eh_frame_hdr = false;
var link_emit_relocs = false;
var each_lib_rpath: ?bool = null;
var sysroot: ?[]const u8 = null;
var libc_paths_file: ?[]const u8 = try optionalStringEnvVar(arena, "ZIG_LIBC");
var machine_code_model: std.builtin.CodeModel = .default;
var runtime_args_start: ?usize = null;
@@ -859,6 +861,10 @@ fn buildOutputType(
if (i + 1 >= args.len) fatal("expected parameter after {s}", .{arg});
i += 1;
target_dynamic_linker = args[i];
} else if (mem.eql(u8, arg, "--sysroot")) {
if (i + 1 >= args.len) fatal("expected parameter after {s}", .{arg});
i += 1;
sysroot = args[i];
} else if (mem.eql(u8, arg, "--libc")) {
if (i + 1 >= args.len) fatal("expected parameter after {s}", .{arg});
i += 1;
@@ -1621,7 +1627,9 @@ fn buildOutputType(
want_native_include_dirs = true;
}
if (cross_target.isNativeOs() and (system_libs.items.len != 0 or want_native_include_dirs)) {
if (sysroot == null and cross_target.isNativeOs() and
(system_libs.items.len != 0 or want_native_include_dirs))
{
const paths = std.zig.system.NativePaths.detect(arena, target_info) catch |err| {
fatal("unable to detect native system paths: {s}", .{@errorName(err)});
};
@@ -1898,6 +1906,7 @@ fn buildOutputType(
.is_native_os = cross_target.isNativeOs(),
.is_native_abi = cross_target.isNativeAbi(),
.dynamic_linker = target_info.dynamic_linker.get(),
.sysroot = sysroot,
.output_mode = output_mode,
.root_pkg = root_pkg,
.emit_bin = emit_bin_loc,