Link sanitizer runtimes instead of injecting crate dependencies

Author: tmiasko

src/bootstrap/check.rs

@@ -48,7 +48,7 @@ impl Step for Std {
         let compiler = builder.compiler(0, builder.config.build);
 
         let mut cargo = builder.cargo(compiler, Mode::Std, target, cargo_subcommand(builder.kind));
-        std_cargo(builder, &compiler, target, &mut cargo);
+        std_cargo(builder, target, &mut cargo);
 
         builder.info(&format!("Checking std artifacts ({} -> {})", &compiler.host, target));
         run_cargo(builder,

src/bootstrap/compile.rs

@@ -94,7 +94,7 @@ impl Step for Std {
         target_deps.extend(copy_third_party_objects(builder, &compiler, target).into_iter());
 
         let mut cargo = builder.cargo(compiler, Mode::Std, target, "build");
-        std_cargo(builder, &compiler, target, &mut cargo);
+        std_cargo(builder, target, &mut cargo);
 
         builder.info(&format!("Building stage{} std artifacts ({} -> {})", compiler.stage,
                 &compiler.host, target));
@@ -163,7 +163,6 @@ fn copy_third_party_objects(builder: &Builder<'_>, compiler: &Compiler, target:
 /// Configure cargo to compile the standard library, adding appropriate env vars
 /// and such.
 pub fn std_cargo(builder: &Builder<'_>,
-                 compiler: &Compiler,
                  target: Interned<String>,
                  cargo: &mut Cargo) {
     if let Some(target) = env::var_os("MACOSX_STD_DEPLOYMENT_TARGET") {
@@ -208,21 +207,6 @@ pub fn std_cargo(builder: &Builder<'_>,
         let mut features = builder.std_features();
         features.push_str(&compiler_builtins_c_feature);
 
-        if compiler.stage != 0 && builder.config.sanitizers {
-            // This variable is used by the sanitizer runtime crates, e.g.
-            // rustc_lsan, to build the sanitizer runtime from C code
-            // When this variable is missing, those crates won't compile the C code,
-            // so we don't set this variable during stage0 where llvm-config is
-            // missing
-            // We also only build the runtimes when --enable-sanitizers (or its
-            // config.toml equivalent) is used
-            let llvm_config = builder.ensure(native::Llvm {
-                target: builder.config.build,
-            });
-            cargo.env("LLVM_CONFIG", llvm_config);
-            cargo.env("RUSTC_BUILD_SANITIZERS", "1");
-        }
-
         cargo.arg("--features").arg(features)
             .arg("--manifest-path")
             .arg(builder.src.join("src/libtest/Cargo.toml"));
@@ -281,30 +265,105 @@ impl Step for StdLink {
         let hostdir = builder.sysroot_libdir(target_compiler, compiler.host);
         add_to_sysroot(builder, &libdir, &hostdir, &libstd_stamp(builder, compiler, target));
 
-        if builder.config.sanitizers && compiler.stage != 0 && target == "x86_64-apple-darwin" {
-            // The sanitizers are only built in stage1 or above, so the dylibs will
-            // be missing in stage0 and causes panic. See the `std()` function above
-            // for reason why the sanitizers are not built in stage0.
-            copy_apple_sanitizer_dylibs(builder, &builder.native_dir(target), "osx", &libdir);
+        if builder.config.sanitizers && compiler.stage != 0 {
+            // The sanitizers are only copied in stage1 or above,
+            // to avoid creating dependency on LLVM.
+            copy_sanitizers(builder, &target_compiler, target);
         }
     }
 }
 
-fn copy_apple_sanitizer_dylibs(
-    builder: &Builder<'_>,
-    native_dir: &Path,
-    platform: &str,
-    into: &Path,
-) {
-    for &sanitizer in &["asan", "tsan"] {
-        let filename = format!("lib__rustc__clang_rt.{}_{}_dynamic.dylib", sanitizer, platform);
-        let mut src_path = native_dir.join(sanitizer);
-        src_path.push("build");
-        src_path.push("lib");
-        src_path.push("darwin");
-        src_path.push(&filename);
-        builder.copy(&src_path, &into.join(filename));
+/// Copies sanitizer runtime libraries into target libdir.
+fn copy_sanitizers(builder: &Builder<'_>, target_compiler: &Compiler, target: Interned<String>) {
+    let sanitizers = supported_sanitizers(target);
+    if sanitizers.is_empty() {
+        return;
+    }
+
+    let llvm_config: PathBuf = builder.ensure(native::Llvm {
+        target: target_compiler.host,
+    });
+    if builder.config.dry_run {
+        return;
+    }
+
+    // The compiler-rt installs sanitizer runtimes into clang resource directory.
+    let clang_resourcedir = clang_resourcedir(&llvm_config);
+    let libdir = builder.sysroot_libdir(*target_compiler, target);
+
+    for (path, name) in &sanitizers {
+        let src = clang_resourcedir.join(path);
+        let dst = libdir.join(name);
+        if !src.exists() {
+            println!("Ignoring missing runtime: {}", src.display());
+            continue;
+        }
+        builder.copy(&src, &dst);
+
+        if target == "x86_64-apple-darwin" {
+            // Update the library install name reflect the fact it has been renamed.
+            let status = Command::new("install_name_tool")
+                .arg("-id")
+                .arg(format!("@rpath/{}", name))
+                .arg(&dst)
+                .status()
+                .expect("failed to execute `install_name_tool`");
+            assert!(status.success());
+        }
+    }
+}
+
+/// Returns path to clang's resource directory.
+fn clang_resourcedir(llvm_config: &Path) -> PathBuf {
+    let llvm_version = output(Command::new(&llvm_config).arg("--version"));
+    let llvm_version = llvm_version.trim();
+    let llvm_libdir = output(Command::new(&llvm_config).arg("--libdir"));
+    let llvm_libdir = PathBuf::from(llvm_libdir.trim());
+
+    // Determine CLANG_VERSION by stripping LLVM_VERSION_SUFFIX from LLVM_VERSION.
+    let mut non_digits = 0;
+    let mut third_non_digit = llvm_version.len();
+    for (i, c) in llvm_version.char_indices() {
+        if !c.is_digit(10) {
+            non_digits += 1;
+            if non_digits == 3 {
+                third_non_digit = i;
+                break;
+            }
+        }
+    }
+    let clang_version = &llvm_version[..third_non_digit];
+    llvm_libdir.join("clang").join(&clang_version)
+}
+
+/// Returns a list of paths to sanitizer libraries supported on given target,
+/// and corresponding names we plan to give them when placed in target libdir.
+///
+/// Returned paths are relative to clang's resource directory.
+fn supported_sanitizers(target: Interned<String>) -> Vec<(PathBuf, String)> {
+    let sanitizers = &["asan", "lsan", "msan", "tsan"];
+    let mut result = Vec::new();
+    match &*target {
+        "x86_64-apple-darwin" => {
+            let srcdir = Path::new("lib/darwin");
+            for s in sanitizers {
+                let src = format!("libclang_rt.{}_osx_dynamic.dylib", s);
+                let dst = format!("librustc_rt.{}.dylib", s);
+                result.push((srcdir.join(src), dst));
+             }
+
+        }
+        "x86_64-unknown-linux-gnu" => {
+            let srcdir = Path::new("lib/linux");
+            for s in sanitizers {
+                let src = format!("libclang_rt.{}-x86_64.a", s);
+                let dst = format!("librustc_rt.{}.a", s);
+                result.push((srcdir.join(src), dst));
+            }
+        }
+        _ => {}
     }
+    result
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]

src/bootstrap/doc.rs

@@ -458,7 +458,7 @@ impl Step for Std {
 
         let run_cargo_rustdoc_for = |package: &str| {
             let mut cargo = builder.cargo(compiler, Mode::Std, target, "rustdoc");
-            compile::std_cargo(builder, &compiler, target, &mut cargo);
+            compile::std_cargo(builder, target, &mut cargo);
 
             // Keep a whitelist so we do not build internal stdlib crates, these will be
             // build by the rustc step later if enabled.

src/bootstrap/native.rs

@@ -186,6 +186,13 @@ impl Step for Llvm {
             enabled_llvm_projects.push("compiler-rt");
         }
 
+        if builder.config.sanitizers {
+            enabled_llvm_projects.push("compiler-rt");
+            cfg.define("COMPILER_RT_BUILD_SANITIZERS", "ON");
+            // Avoids building instrumented version of libcxx.
+            cfg.define("COMPILER_RT_USE_LIBCXX", "OFF");
+        }
+
         if builder.config.lldb_enabled {
             enabled_llvm_projects.push("clang");
             enabled_llvm_projects.push("lldb");

src/bootstrap/test.rs

@@ -1764,7 +1764,7 @@ impl Step for Crate {
         let mut cargo = builder.cargo(compiler, mode, target, test_kind.subcommand());
         match mode {
             Mode::Std => {
-                compile::std_cargo(builder, &compiler, target, &mut cargo);
+                compile::std_cargo(builder, target, &mut cargo);
             }
             Mode::Rustc => {
                 builder.ensure(compile::Rustc { compiler, target });

src/librustc/session/mod.rs

@@ -1297,6 +1297,17 @@ fn validate_commandline_args_with_session_available(sess: &Session) {
                   with `-Cpanic=unwind` on Windows when targeting MSVC. \
                   See https://github.com/rust-lang/rust/issues/61002 for details.");
     }
+
+    // Sanitizers can only be used on some tested platforms.
+    if let Some(ref sanitizer) = sess.opts.debugging_opts.sanitizer {
+        const SUPPORTED_TARGETS: &[&str] = &["x86_64-unknown-linux-gnu", "x86_64-apple-darwin"];
+        if !SUPPORTED_TARGETS.contains(&&*sess.opts.target_triple.triple()) {
+            sess.err(&format!("{:?}Sanitizer only works with the `{}` target",
+                sanitizer,
+                SUPPORTED_TARGETS.join("` or `")
+            ));
+        }
+    }
 }
 
 /// Hash value constructed out of all the `-C metadata` arguments passed to the

src/librustc_codegen_ssa/back/link.rs

@@ -522,6 +522,7 @@ fn link_natively<'a, B: ArchiveBuilder<'a>>(sess: &'a Session,
 
     {
         let mut linker = codegen_results.linker_info.to_linker(cmd, &sess, flavor, target_cpu);
+        link_sanitizer_runtime(sess, crate_type, &mut *linker);
         link_args::<B>(&mut *linker, flavor, sess, crate_type, tmpdir,
                   out_filename, codegen_results);
         cmd = linker.finalize();
@@ -725,6 +726,49 @@ fn link_natively<'a, B: ArchiveBuilder<'a>>(sess: &'a Session,
     }
 }
 
+fn link_sanitizer_runtime(sess: &Session,
+                          crate_type: config::CrateType,
+                          linker: &mut dyn Linker) {
+    let sanitizer = match &sess.opts.debugging_opts.sanitizer {
+        Some(s) => s,
+        None => return,
+    };
+
+    if crate_type != config::CrateType::Executable {
+        return;
+    }
+
+    let name = match sanitizer {
+        Sanitizer::Address => "asan",
+        Sanitizer::Leak => "lsan",
+        Sanitizer::Memory => "msan",
+        Sanitizer::Thread => "tsan",
+    };
+
+    let default_sysroot = filesearch::get_or_default_sysroot();
+    let default_tlib = filesearch::make_target_lib_path(
+        &default_sysroot, sess.opts.target_triple.triple());
+
+    match sess.opts.target_triple.triple() {
+        "x86_64-apple-darwin" => {
+            // On Apple platforms, the sanitizer is always built as a dylib, and
+            // LLVM will link to `@rpath/*.dylib`, so we need to specify an
+            // rpath to the library as well (the rpath should be absolute, see
+            // PR #41352 for details).
+            let filename = format!("librustc_rt.{}.dylib", name);
+            let rpath = default_tlib.to_str().expect("non-utf8 component in path");
+            linker.args(&["-Wl,-rpath".into(), "-Xlinker".into(), rpath.into()]);
+            linker.link_dylib(Symbol::intern(&filename));
+        }
+        "x86_64-unknown-linux-gnu" => {
+            let filename = format!("librustc_rt.{}.a", name);
+            let path = default_tlib.join(&filename);
+            linker.link_whole_rlib(&path);
+        }
+        _ => {}
+    }
+}
+
 /// Returns a boolean indicating whether the specified crate should be ignored
 /// during LTO.
 ///
@@ -1391,11 +1435,6 @@ fn add_upstream_rust_crates<'a, B: ArchiveBuilder<'a>>(
             _ if codegen_results.crate_info.profiler_runtime == Some(cnum) => {
                 add_static_crate::<B>(cmd, sess, codegen_results, tmpdir, crate_type, cnum);
             }
-            _ if codegen_results.crate_info.sanitizer_runtime == Some(cnum) &&
-                  crate_type == config::CrateType::Executable => {
-                // Link the sanitizer runtimes only if we are actually producing an executable
-                link_sanitizer_runtime::<B>(cmd, sess, codegen_results, tmpdir, cnum);
-            }
             // compiler-builtins are always placed last to ensure that they're
             // linked correctly.
             _ if codegen_results.crate_info.compiler_builtins == Some(cnum) => {
@@ -1435,45 +1474,6 @@ fn add_upstream_rust_crates<'a, B: ArchiveBuilder<'a>>(
         }
     }
 
-    // We must link the sanitizer runtime using -Wl,--whole-archive but since
-    // it's packed in a .rlib, it contains stuff that are not objects that will
-    // make the linker error. So we must remove those bits from the .rlib before
-    // linking it.
-    fn link_sanitizer_runtime<'a, B: ArchiveBuilder<'a>>(cmd: &mut dyn Linker,
-                              sess: &'a Session,
-                              codegen_results: &CodegenResults,
-                              tmpdir: &Path,
-                              cnum: CrateNum) {
-        let src = &codegen_results.crate_info.used_crate_source[&cnum];
-        let cratepath = &src.rlib.as_ref().unwrap().0;
-
-        if sess.target.target.options.is_like_osx {
-            // On Apple platforms, the sanitizer is always built as a dylib, and
-            // LLVM will link to `@rpath/*.dylib`, so we need to specify an
-            // rpath to the library as well (the rpath should be absolute, see
-            // PR #41352 for details).
-            //
-            // FIXME: Remove this logic into librustc_*san once Cargo supports it
-            let rpath = cratepath.parent().unwrap();
-            let rpath = rpath.to_str().expect("non-utf8 component in path");
-            cmd.args(&["-Wl,-rpath".into(), "-Xlinker".into(), rpath.into()]);
-        }
-
-        let dst = tmpdir.join(cratepath.file_name().unwrap());
-        let mut archive = <B as ArchiveBuilder>::new(sess, &dst, Some(cratepath));
-        archive.update_symbols();
-
-        for f in archive.src_files() {
-            if f.ends_with(RLIB_BYTECODE_EXTENSION) || f == METADATA_FILENAME {
-                archive.remove_file(&f);
-            }
-        }
-
-        archive.build();
-
-        cmd.link_whole_rlib(&dst);
-    }
-
     // Adds the static "rlib" versions of all crates to the command line.
     // There's a bit of magic which happens here specifically related to LTO and
     // dynamic libraries. Specifically: