[WIP] add -Z split_bundled_libs

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -318,37 +318,56 @@ fn link_rlib<'a, B: ArchiveBuilder<'a>>(
     // metadata of the rlib we're generating somehow.
     for lib in codegen_results.crate_info.used_libraries.iter() {
         match lib.kind {
-            NativeLibKind::Static { bundle: None | Some(true), whole_archive: Some(true) }
-                if flavor == RlibFlavor::Normal =>
-            {
-                // Don't allow mixing +bundle with +whole_archive since an rlib may contain
-                // multiple native libs, some of which are +whole-archive and some of which are
-                // -whole-archive and it isn't clear how we can currently handle such a
-                // situation correctly.
-                // See https://github.com/rust-lang/rust/issues/88085#issuecomment-901050897
-                sess.err(
-                    "the linking modifiers `+bundle` and `+whole-archive` are not compatible \
-                        with each other when generating rlibs",
+            NativeLibKind::Static { bundle: None | Some(true), whole_archive } => {
+                if flavor == RlibFlavor::Normal
+                    && whole_archive == Some(true)
+                    && !sess.opts.unstable_opts.split_bundled_libs
+                {
+                    // Don't allow mixing +bundle with +whole_archive since an rlib may contain
+                    // multiple native libs, some of which are +whole-archive and some of which are
+                    // -whole-archive and it isn't clear how we can currently handle such a
+                    // situation correctly.
+                    // See https://github.com/rust-lang/rust/issues/88085#issuecomment-901050897
+                    sess.err(
+                        "the linking modifiers `+bundle` and `+whole-archive` are not compatible \
+                                with each other when generating rlibs",
+                    );
+                }
+
+                let Some(name) = lib.name else {
+                    continue;
+                };
+
+                let location = find_library(
+                    name.as_str(),
+                    lib.verbatim.unwrap_or(false),
+                    &lib_search_paths,
+                    sess,
                 );
+
+                if flavor == RlibFlavor::Normal && sess.opts.unstable_opts.split_bundled_libs {
+                    let suffix = &sess.target.staticlib_suffix;
+                    let bundle_lib =
+                        PathBuf::from(format!("{}.bundle.{name}{suffix}", out_filename.display()));
+                    fs::copy(location, bundle_lib).unwrap_or_else(|e| {
+                        sess.fatal(format!("Unable to create bundle lib: {}", e));
+                    });
+                } else {
+                    ab.add_archive(&location, |_| false).unwrap_or_else(|e| {
+                        sess.fatal(&format!(
+                            "failed to add native library {}: {}",
+                            location.to_string_lossy(),
+                            e
+                        ));
+                    });
+                }
             }
-            NativeLibKind::Static { bundle: None | Some(true), .. } => {}
             NativeLibKind::Static { bundle: Some(false), .. }
             | NativeLibKind::Dylib { .. }
             | NativeLibKind::Framework { .. }
             | NativeLibKind::RawDylib
             | NativeLibKind::Unspecified => continue,
         }
-        if let Some(name) = lib.name {
-            let location =
-                find_library(name.as_str(), lib.verbatim.unwrap_or(false), &lib_search_paths, sess);
-            ab.add_archive(&location, |_| false).unwrap_or_else(|e| {
-                sess.fatal(&format!(
-                    "failed to add native library {}: {}",
-                    location.to_string_lossy(),
-                    e
-                ));
-            });
-        }
     }
 
     for (raw_dylib_name, raw_dylib_imports) in
@@ -2380,20 +2399,41 @@ fn add_upstream_rust_crates<'a, B: ArchiveBuilder<'a>>(
                             (lib.name, lib.kind, lib.verbatim)
                         };
 
-                        if let NativeLibKind::Static { bundle: Some(false), whole_archive } =
-                            lib.kind
-                        {
-                            let verbatim = lib.verbatim.unwrap_or(false);
-                            if whole_archive == Some(true) {
-                                cmd.link_whole_staticlib(
-                                    name,
-                                    verbatim,
-                                    search_path.get_or_init(|| archive_search_paths(sess)),
-                                );
-                            } else {
-                                cmd.link_staticlib(name, verbatim);
+                        match lib.kind {
+                            NativeLibKind::Static { bundle: None | Some(true), whole_archive }
+                                if sess.opts.unstable_opts.split_bundled_libs =>
+                            {
+                                let suffix = &sess.target.staticlib_suffix;
+                                let cratepath = &src.rlib.as_ref().unwrap().0;
+                                let bundle_lib = PathBuf::from(format!(
+                                    "{}.bundle.{name}{suffix}",
+                                    cratepath.display()
+                                ));
+                                if whole_archive == Some(true) {
+                                    cmd.link_whole_rlib(&fix_windows_verbatim_for_gcc(&bundle_lib));
+                                } else {
+                                    cmd.link_rlib(&fix_windows_verbatim_for_gcc(&bundle_lib));
+                                }
                             }
-                        }
+
+                            NativeLibKind::Static { bundle: Some(false), whole_archive } => {
+                                let verbatim = lib.verbatim.unwrap_or(false);
+                                if whole_archive == Some(true) {
+                                    cmd.link_whole_staticlib(
+                                        name,
+                                        verbatim,
+                                        search_path.get_or_init(|| archive_search_paths(sess)),
+                                    );
+                                } else {
+                                    cmd.link_staticlib(name, verbatim);
+                                }
+                            }
+                            NativeLibKind::Static { bundle: None | Some(true), .. }
+                            | NativeLibKind::Dylib { .. }
+                            | NativeLibKind::Framework { .. }
+                            | NativeLibKind::RawDylib
+                            | NativeLibKind::Unspecified => {}
+                        };
                     }
                 }
             }

compiler/rustc_interface/src/tests.rs

@@ -787,6 +787,7 @@ fn test_unstable_options_tracking_hash() {
     tracked!(share_generics, Some(true));
     tracked!(show_span, Some(String::from("abc")));
     tracked!(simulate_remapped_rust_src_base, Some(PathBuf::from("/rustc/abc")));
+    tracked!(split_bundled_libs, true);
     tracked!(src_hash_algorithm, Some(SourceFileHashAlgorithm::Sha1));
     tracked!(stack_protector, StackProtector::All);
     tracked!(symbol_mangling_version, Some(SymbolManglingVersion::V0));

compiler/rustc_session/src/options.rs

@@ -1519,15 +1519,8 @@ options! {
     /// o/w tests have closure@path
     span_free_formats: bool = (false, parse_bool, [UNTRACKED],
         "exclude spans when debug-printing compiler state (default: no)"),
-    src_hash_algorithm: Option<SourceFileHashAlgorithm> = (None, parse_src_file_hash, [TRACKED],
-        "hash algorithm of source files in debug info (`md5`, `sha1`, or `sha256`)"),
-    #[cfg_attr(not(bootstrap), rustc_lint_opt_deny_field_access("use `Session::stack_protector` instead of this field"))]
-    stack_protector: StackProtector = (StackProtector::None, parse_stack_protector, [TRACKED],
-        "control stack smash protection strategy (`rustc --print stack-protector-strategies` for details)"),
-    strict_init_checks: bool = (false, parse_bool, [TRACKED],
-        "control if mem::uninitialized and mem::zeroed panic on more UB"),
-    strip: Strip = (Strip::None, parse_strip, [UNTRACKED],
-        "tell the linker which information to strip (`none` (default), `debuginfo` or `symbols`)"),
+    split_bundled_libs: bool = (false, parse_bool, [TRACKED],
+        "if libfoo.rlib is the rlib, then libfoo.rlib.bundle.* are the corresponding bundled static libraries"),
     split_dwarf_kind: SplitDwarfKind = (SplitDwarfKind::Split, parse_split_dwarf_kind, [TRACKED],
         "split dwarf variant (only if -Csplit-debuginfo is enabled and on relevant platform)
         (default: `split`)
@@ -1539,6 +1532,15 @@ options! {
     split_dwarf_inlining: bool = (true, parse_bool, [TRACKED],
         "provide minimal debug info in the object/executable to facilitate online \
          symbolication/stack traces in the absence of .dwo/.dwp files when using Split DWARF"),
+    src_hash_algorithm: Option<SourceFileHashAlgorithm> = (None, parse_src_file_hash, [TRACKED],
+        "hash algorithm of source files in debug info (`md5`, `sha1`, or `sha256`)"),
+    #[cfg_attr(not(bootstrap), rustc_lint_opt_deny_field_access("use `Session::stack_protector` instead of this field"))]
+    stack_protector: StackProtector = (StackProtector::None, parse_stack_protector, [TRACKED],
+        "control stack smash protection strategy (`rustc --print stack-protector-strategies` for details)"),
+    strict_init_checks: bool = (false, parse_bool, [TRACKED],
+        "control if mem::uninitialized and mem::zeroed panic on more UB"),
+    strip: Strip = (Strip::None, parse_strip, [UNTRACKED],
+        "tell the linker which information to strip (`none` (default), `debuginfo` or `symbols`)"),
     symbol_mangling_version: Option<SymbolManglingVersion> = (None,
         parse_symbol_mangling_version, [TRACKED],
         "which mangling version to use for symbol names ('legacy' (default) or 'v0')"),

src/test/run-make/native-link-modifier-bundle/Makefile

@@ -6,6 +6,9 @@
 # We're using the llvm-nm instead of the system nm to ensure it is compatible
 # with the LLVM bitcode generated by rustc.
 NM = "$(LLVM_BIN_DIR)"/llvm-nm
+SPLIT = "-Zsplit-bundled-libs"
+BUNDLED_LIB = "libbundled.rlib.bundle.native-staticlib.a"
+
 
 all: $(call NATIVE_STATICLIB,native-staticlib)
 	# Build a staticlib and a rlib, the `native_func` symbol will be bundled into them
@@ -31,3 +34,15 @@ all: $(call NATIVE_STATICLIB,native-staticlib)
 	# The cdylib will contain the `native_func` symbol in the end
 	$(RUSTC) cdylib-non-bundled.rs --crate-type=cdylib --print link-args | $(CGREP) -e '-l[" ]*native-staticlib'
 	$(NM) $(call DYLIB,cdylib_non_bundled) | $(CGREP) -e "[Tt] _*native_func"
+
+	# Build a staticlib and a rlib, the `native_func` symbol will be bundled only into staticlib
+	$(RUSTC) bundled.rs --crate-type=staticlib --crate-type=rlib $(SPLIT) --crate-name=bundled_split
+	$(NM) $(TMPDIR)/libbundled_split.a | $(CGREP) -e "T _*native_func"
+	$(NM) $(TMPDIR)/libbundled_split.a | $(CGREP) -e "U _*native_func"
+	$(NM) $(TMPDIR)/libbundled_split.rlib | $(CGREP) -ve "T _*native_func"
+	$(NM) $(TMPDIR)/libbundled_split.rlib | $(CGREP) -e "U _*native_func"
+
+	# Build a cdylib, `native-staticlib` will appear on the linker line because it was not bundled previously
+	# The cdylib will contain the `native_func` symbol in the end
+	$(RUSTC) cdylib-non-bundled.rs --crate-type=cdylib --print link-args $(SPLIT) --crate-name=cdylib_non_bundled_split | $(CGREP) -e '-l[" ]*native-staticlib'
+	$(NM) $(call DYLIB,cdylib_non_bundled_split) | $(CGREP) -e "[Tt] _*native_func"

src/test/rustdoc-ui/z-help.stdout

@@ -144,10 +144,7 @@
     -Z                               show-span=val -- show spans for compiler debugging (expr|pat|ty)
     -Z                              span-debug=val -- forward proc_macro::Span's `Debug` impl to `Span`
     -Z                       span-free-formats=val -- exclude spans when debug-printing compiler state (default: no)
-    -Z                      src-hash-algorithm=val -- hash algorithm of source files in debug info (`md5`, `sha1`, or `sha256`)
-    -Z                         stack-protector=val -- control stack smash protection strategy (`rustc --print stack-protector-strategies` for details)
-    -Z                      strict-init-checks=val -- control if mem::uninitialized and mem::zeroed panic on more UB
-    -Z                                   strip=val -- tell the linker which information to strip (`none` (default), `debuginfo` or `symbols`)
+    -Z                      split-bundled-libs=val -- if libfoo.rlib is the rlib, then libfoo.rlib.bundle.* are the corresponding bundled static libraries
     -Z                        split-dwarf-kind=val -- split dwarf variant (only if -Csplit-debuginfo is enabled and on relevant platform)
         (default: `split`)
 
@@ -156,6 +153,10 @@
         `single`: sections which do not require relocation are written into object file but ignored
                   by the linker
     -Z                    split-dwarf-inlining=val -- provide minimal debug info in the object/executable to facilitate online symbolication/stack traces in the absence of .dwo/.dwp files when using Split DWARF
+    -Z                      src-hash-algorithm=val -- hash algorithm of source files in debug info (`md5`, `sha1`, or `sha256`)
+    -Z                         stack-protector=val -- control stack smash protection strategy (`rustc --print stack-protector-strategies` for details)
+    -Z                      strict-init-checks=val -- control if mem::uninitialized and mem::zeroed panic on more UB
+    -Z                                   strip=val -- tell the linker which information to strip (`none` (default), `debuginfo` or `symbols`)
     -Z                 symbol-mangling-version=val -- which mangling version to use for symbol names ('legacy' (default) or 'v0')
     -Z                                   teach=val -- show extended diagnostic help (default: no)
     -Z                               temps-dir=val -- the directory the intermediate files are written to