expose glibc version in builtin

Author: andrewrk

src/codegen.cpp

@@ -7918,6 +7918,14 @@ Buf *codegen_generate_builtin_source(CodeGen *g) {
         //assert(EndianBig == 0);
         //assert(EndianLittle == 1);
     }
+    {
+        buf_appendf(contents,
+            "pub const Version = struct {\n"
+            "    major: u32,\n"
+            "    minor: u32,\n"
+            "    patch: u32,\n"
+            "};\n\n");
+    }
     {
         buf_appendf(contents,
         "pub const SubSystem = enum {\n"
@@ -7949,6 +7957,15 @@ Buf *codegen_generate_builtin_source(CodeGen *g) {
     buf_appendf(contents, "pub const os = Os.%s;\n", cur_os);
     buf_appendf(contents, "pub const arch = %s;\n", cur_arch);
     buf_appendf(contents, "pub const abi = Abi.%s;\n", cur_abi);
+    if (g->libc_link_lib != nullptr && g->zig_target->glibc_version != nullptr) {
+        buf_appendf(contents,
+            "pub const glibc_version: ?Version = Version{.major = %d, .minor = %d, .patch = %d};\n",
+                g->zig_target->glibc_version->major,
+                g->zig_target->glibc_version->minor,
+                g->zig_target->glibc_version->patch);
+    } else {
+        buf_appendf(contents, "pub const glibc_version: ?Version = null;\n");
+    }
     buf_appendf(contents, "pub const object_format = ObjectFormat.%s;\n", cur_obj_fmt);
     buf_appendf(contents, "pub const mode = %s;\n", build_mode_to_str(g->build_mode));
     buf_appendf(contents, "pub const link_libc = %s;\n", bool_to_str(g->libc_link_lib != nullptr));
@@ -8005,6 +8022,11 @@ static Error define_builtin_compile_vars(CodeGen *g) {
     cache_int(&cache_hash, g->zig_target->vendor);
     cache_int(&cache_hash, g->zig_target->os);
     cache_int(&cache_hash, g->zig_target->abi);
+    if (g->zig_target->glibc_version != nullptr) {
+        cache_int(&cache_hash, g->zig_target->glibc_version->major);
+        cache_int(&cache_hash, g->zig_target->glibc_version->minor);
+        cache_int(&cache_hash, g->zig_target->glibc_version->patch);
+    }
     cache_bool(&cache_hash, g->have_err_ret_tracing);
     cache_bool(&cache_hash, g->libc_link_lib != nullptr);
     cache_bool(&cache_hash, g->valgrind_support);
@@ -9465,6 +9487,11 @@ static Error check_cache(CodeGen *g, Buf *manifest_dir, Buf *digest) {
     cache_int(ch, g->zig_target->vendor);
     cache_int(ch, g->zig_target->os);
     cache_int(ch, g->zig_target->abi);
+    if (g->zig_target->glibc_version != nullptr) {
+        cache_int(ch, g->zig_target->glibc_version->major);
+        cache_int(ch, g->zig_target->glibc_version->minor);
+        cache_int(ch, g->zig_target->glibc_version->patch);
+    }
     cache_int(ch, detect_subsystem(g));
     cache_bool(ch, g->strip_debug_symbols);
     cache_bool(ch, g->is_test_build);

src/main.cpp

@@ -1015,6 +1015,10 @@ int main(int argc, char **argv) {
         CodeGen *g = codegen_create(main_pkg_path, nullptr, &target,
                 out_type, build_mode, override_lib_dir, override_std_dir, nullptr, nullptr);
         codegen_set_strip(g, strip);
+        for (size_t i = 0; i < link_libs.length; i += 1) {
+            LinkLib *link_lib = codegen_add_link_lib(g, buf_create_from_str(link_libs.at(i)));
+            link_lib->provided_explicitly = true;
+        }
         g->subsystem = subsystem;
         g->valgrind_support = valgrind_support;
         g->want_pic = want_pic;

std/build.zig

@@ -1011,7 +1011,8 @@ pub const LibExeObjStep = struct {
     builder: *Builder,
     name: []const u8,
     target: Target,
-    linker_script: ?[]const u8,
+    linker_script: ?[]const u8 = null,
+    version_script: ?[]const u8 = null,
     out_filename: []const u8,
     is_dynamic: bool,
     version: Version,
@@ -1118,7 +1119,6 @@ pub const LibExeObjStep = struct {
             .root_src = root_src,
             .name = name,
             .target = Target.Native,
-            .linker_script = null,
             .frameworks = BufSet.init(builder.allocator),
             .step = Step.init(name, builder.allocator, make),
             .version = ver,
@@ -1596,7 +1596,12 @@ pub const LibExeObjStep = struct {
 
         if (self.linker_script) |linker_script| {
             zig_args.append("--linker-script") catch unreachable;
-            zig_args.append(linker_script) catch unreachable;
+            zig_args.append(builder.pathFromRoot(linker_script)) catch unreachable;
+        }
+
+        if (self.version_script) |version_script| {
+            try zig_args.append("--version-script");
+            try zig_args.append(builder.pathFromRoot(version_script));
         }
 
         if (self.exec_cmd_args) |exec_cmd_args| {