compiler: Support building FreeBSD crt1.o/Scrt1.o and stub shared libraries.

Only works for FreeBSD 14+. Note that we still default to targeting FreeBSD 13.

Contributes to #2876.

CMakeLists.txt

@@ -586,6 +586,7 @@ set(ZIG_STAGE2_SOURCES
     src/codegen/spirv/spec.zig
     src/crash_report.zig
     src/dev.zig
+    src/libs/freebsd.zig
     src/libs/glibc.zig
     src/introspect.zig
     src/libs/libcxx.zig

src/Compilation.zig

@@ -23,6 +23,7 @@ const build_options = @import("build_options");
 const LibCInstallation = std.zig.LibCInstallation;
 const glibc = @import("libs/glibc.zig");
 const musl = @import("libs/musl.zig");
+const freebsd = @import("libs/freebsd.zig");
 const mingw = @import("libs/mingw.zig");
 const libunwind = @import("libs/libunwind.zig");
 const libcxx = @import("libs/libcxx.zig");
@@ -248,6 +249,7 @@ compiler_rt_obj: ?CrtFile = null,
 fuzzer_lib: ?CrtFile = null,
 
 glibc_so_files: ?glibc.BuiltSharedObjects = null,
+freebsd_so_files: ?freebsd.BuiltSharedObjects = null,
 wasi_emulated_libs: []const wasi_libc.CrtFile,
 
 /// For example `Scrt1.o` and `libc_nonshared.a`. These are populated after building libc from source,
@@ -294,12 +296,14 @@ const QueuedJobs = struct {
     update_builtin_zig: bool,
     musl_crt_file: [@typeInfo(musl.CrtFile).@"enum".fields.len]bool = @splat(false),
     glibc_crt_file: [@typeInfo(glibc.CrtFile).@"enum".fields.len]bool = @splat(false),
+    freebsd_crt_file: [@typeInfo(freebsd.CrtFile).@"enum".fields.len]bool = @splat(false),
     /// one of WASI libc static objects
     wasi_libc_crt_file: [@typeInfo(wasi_libc.CrtFile).@"enum".fields.len]bool = @splat(false),
     /// one of the mingw-w64 static objects
     mingw_crt_file: [@typeInfo(mingw.CrtFile).@"enum".fields.len]bool = @splat(false),
     /// all of the glibc shared objects
     glibc_shared_objects: bool = false,
+    freebsd_shared_objects: bool = false,
     /// libunwind.a, usually needed when linking libc
     libunwind: bool = false,
     libcxx: bool = false,
@@ -789,6 +793,8 @@ pub const MiscTask = enum {
     glibc_crt_file,
     glibc_shared_objects,
     musl_crt_file,
+    freebsd_crt_file,
+    freebsd_shared_objects,
     mingw_crt_file,
     windows_import_lib,
     libunwind,
@@ -823,6 +829,9 @@ pub const MiscTask = enum {
     @"glibc libc_nonshared.a",
     @"glibc shared object",
 
+    @"freebsd libc Scrt1.o",
+    @"freebsd libc shared object",
+
     @"mingw-w64 crt2.o",
     @"mingw-w64 dllcrt2.o",
     @"mingw-w64 libmingw32.lib",
@@ -1874,6 +1883,16 @@ pub fn create(gpa: Allocator, arena: Allocator, options: CreateOptions) !*Compil
 
                     comp.queued_jobs.glibc_crt_file[@intFromEnum(glibc.CrtFile.libc_nonshared_a)] = true;
                     comp.remaining_prelink_tasks += 1;
+                } else if (target.isFreeBSDLibC()) {
+                    if (!std.zig.target.canBuildLibC(target)) return error.LibCUnavailable;
+
+                    if (freebsd.needsCrt0(comp.config.output_mode)) |f| {
+                        comp.queued_jobs.freebsd_crt_file[@intFromEnum(f)] = true;
+                        comp.remaining_prelink_tasks += 1;
+                    }
+
+                    comp.queued_jobs.freebsd_shared_objects = true;
+                    comp.remaining_prelink_tasks += freebsd.sharedObjectsCount();
                 } else if (target.isWasiLibC()) {
                     if (!std.zig.target.canBuildLibC(target)) return error.LibCUnavailable;
 
@@ -2028,6 +2047,10 @@ pub fn destroy(comp: *Compilation) void {
         glibc_file.deinit(gpa);
     }
 
+    if (comp.freebsd_so_files) |*freebsd_file| {
+        freebsd_file.deinit(gpa);
+    }
+
     for (comp.c_object_table.keys()) |key| {
         key.destroy(gpa);
     }
@@ -3839,6 +3862,10 @@ fn performAllTheWorkInner(
         comp.link_task_wait_group.spawnManager(buildGlibcSharedObjects, .{ comp, main_progress_node });
     }
 
+    if (comp.queued_jobs.freebsd_shared_objects) {
+        comp.link_task_wait_group.spawnManager(buildFreeBSDSharedObjects, .{ comp, main_progress_node });
+    }
+
     if (comp.queued_jobs.libunwind) {
         comp.link_task_wait_group.spawnManager(buildLibUnwind, .{ comp, main_progress_node });
     }
@@ -3873,6 +3900,13 @@ fn performAllTheWorkInner(
         }
     }
 
+    for (0..@typeInfo(freebsd.CrtFile).@"enum".fields.len) |i| {
+        if (comp.queued_jobs.freebsd_crt_file[i]) {
+            const tag: freebsd.CrtFile = @enumFromInt(i);
+            comp.link_task_wait_group.spawnManager(buildFreeBSDCrtFile, .{ comp, tag, main_progress_node });
+        }
+    }
+
     for (0..@typeInfo(wasi_libc.CrtFile).@"enum".fields.len) |i| {
         if (comp.queued_jobs.wasi_libc_crt_file[i]) {
             const tag: wasi_libc.CrtFile = @enumFromInt(i);
@@ -4876,6 +4910,29 @@ fn buildGlibcSharedObjects(comp: *Compilation, prog_node: std.Progress.Node) voi
     }
 }
 
+fn buildFreeBSDCrtFile(comp: *Compilation, crt_file: freebsd.CrtFile, prog_node: std.Progress.Node) void {
+    if (freebsd.buildCrtFile(comp, crt_file, prog_node)) |_| {
+        comp.queued_jobs.freebsd_crt_file[@intFromEnum(crt_file)] = false;
+    } else |err| switch (err) {
+        error.SubCompilationFailed => return, // error reported already
+        else => comp.lockAndSetMiscFailure(.freebsd_crt_file, "unable to build FreeBSD {s}: {s}", .{
+            @tagName(crt_file), @errorName(err),
+        }),
+    }
+}
+
+fn buildFreeBSDSharedObjects(comp: *Compilation, prog_node: std.Progress.Node) void {
+    if (freebsd.buildSharedObjects(comp, prog_node)) |_| {
+        // The job should no longer be queued up since it succeeded.
+        comp.queued_jobs.freebsd_shared_objects = false;
+    } else |err| switch (err) {
+        error.SubCompilationFailed => return, // error reported already
+        else => comp.lockAndSetMiscFailure(.freebsd_shared_objects, "unable to build FreeBSD libc shared objects: {s}", .{
+            @errorName(err),
+        }),
+    }
+}
+
 fn buildMingwCrtFile(comp: *Compilation, crt_file: mingw.CrtFile, prog_node: std.Progress.Node) void {
     if (mingw.buildCrtFile(comp, crt_file, prog_node)) |_| {
         comp.queued_jobs.mingw_crt_file[@intFromEnum(crt_file)] = false;

src/link/Elf.zig

@@ -2058,11 +2058,18 @@ fn linkWithLLD(self: *Elf, arena: Allocator, tid: Zcu.PerThread.Id, prog_node: s
                         try argv.append(lib_path);
                     }
                     try argv.append(try comp.crtFileAsString(arena, "libc_nonshared.a"));
-                } else if (target.abi.isMusl()) {
+                } else if (target.isMuslLibC()) {
                     try argv.append(try comp.crtFileAsString(arena, switch (link_mode) {
                         .static => "libc.a",
                         .dynamic => "libc.so",
                     }));
+                } else if (target.isFreeBSDLibC()) {
+                    for (freebsd.libs) |lib| {
+                        const lib_path = try std.fmt.allocPrint(arena, "{}{c}lib{s}.so.{d}", .{
+                            comp.freebsd_so_files.?.dir_path, fs.path.sep, lib.name, lib.sover,
+                        });
+                        try argv.append(lib_path);
+                    }
                 } else {
                     diags.flags.missing_libc = true;
                 }
@@ -5280,8 +5287,9 @@ const dev = @import("../dev.zig");
 const eh_frame = @import("Elf/eh_frame.zig");
 const gc = @import("Elf/gc.zig");
 const glibc = @import("../libs/glibc.zig");
-const link = @import("../link.zig");
 const musl = @import("../libs/musl.zig");
+const freebsd = @import("../libs/freebsd.zig");
+const link = @import("../link.zig");
 const relocatable = @import("Elf/relocatable.zig");
 const relocation = @import("Elf/relocation.zig");
 const target_util = @import("../target.zig");