diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index 20e75f0fdfd20..f223441663d5d 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -58,7 +58,7 @@ use super::command::Command;
 use super::linker::{self, Linker};
 use super::metadata::{MetadataPosition, create_wrapper_file};
 use super::rpath::{self, RPathConfig};
-use super::{apple, versioned_llvm_target};
+use super::{apple, rmeta_link, versioned_llvm_target};
 use crate::base::needs_allocator_shim_for_linking;
 use crate::{
     CodegenLintLevels, CompiledModule, CompiledModules, CrateInfo, NativeLib, errors,
@@ -329,8 +329,11 @@ fn link_rlib<'a>(
         RlibFlavor::StaticlibBase => None,
     };
 
+    let mut rust_object_files: Vec<String> = Vec::new();
+
     for m in &compiled_modules.modules {
         if let Some(obj) = m.object.as_ref() {
+            rust_object_files.push(obj.file_name().unwrap().to_str().unwrap().to_string());
             ab.add_file(obj);
         }
 
@@ -442,6 +445,16 @@ fn link_rlib<'a>(
         ab.add_file(&lib)
     }
 
+    // Add the rlib digest as the very last member. This records which archive
+    // members are Rust object files, replacing filename-based heuristics.
+    if matches!(flavor, RlibFlavor::Normal) {
+        let digest = rmeta_link::RmetaLink { rust_object_files };
+        let digest_data = digest.encode();
+        let (wrapper, _) = create_wrapper_file(sess, rmeta_link::SECTION.to_string(), &digest_data);
+        let digest_file = emit_wrapper_file(sess, &wrapper, tmpdir.as_ref(), rmeta_link::FILENAME);
+        ab.add_file(&digest_file);
+    }
+
     ab
 }
 
@@ -486,16 +499,18 @@ fn link_staticlib(
         let relevant_libs: FxIndexSet<_> = relevant.filter_map(|lib| lib.filename).collect();
 
         let bundled_libs: FxIndexSet<_> = native_libs.filter_map(|lib| lib.filename).collect();
+        let archive_map = unsafe { Mmap::map(File::open(path).unwrap()).unwrap() };
+        let digest = rmeta_link::read(&archive_map, path).unwrap();
         ab.add_archive(
             path,
             Box::new(move |fname: &str| {
-                // Ignore metadata files, no matter the name.
-                if fname == METADATA_FILENAME {
+                // Ignore metadata and rlib digest files.
+                if fname == METADATA_FILENAME || fname == rmeta_link::FILENAME {
                     return true;
                 }
 
-                // Don't include Rust objects if LTO is enabled
-                if lto && looks_like_rust_object_file(fname) {
+                // Don't include Rust objects if LTO is enabled.
+                if lto && digest.rust_object_files.iter().any(|f| f == fname) {
                     return true;
                 }
 
@@ -3153,7 +3168,7 @@ fn add_static_crate(
         if let Err(error) = archive.add_archive(
             cratepath,
             Box::new(move |f| {
-                if f == METADATA_FILENAME {
+                if f == METADATA_FILENAME || f == rmeta_link::FILENAME {
                     return true;
                 }
 
diff --git a/compiler/rustc_codegen_ssa/src/back/mod.rs b/compiler/rustc_codegen_ssa/src/back/mod.rs
index 8d1adb9993038..7b34d80852769 100644
--- a/compiler/rustc_codegen_ssa/src/back/mod.rs
+++ b/compiler/rustc_codegen_ssa/src/back/mod.rs
@@ -9,6 +9,7 @@ pub mod link;
 pub(crate) mod linker;
 pub mod lto;
 pub mod metadata;
+pub(crate) mod rmeta_link;
 pub(crate) mod rpath;
 pub mod symbol_export;
 pub mod write;
diff --git a/compiler/rustc_codegen_ssa/src/back/rmeta_link.rs b/compiler/rustc_codegen_ssa/src/back/rmeta_link.rs
new file mode 100644
index 0000000000000..d10c860676355
--- /dev/null
+++ b/compiler/rustc_codegen_ssa/src/back/rmeta_link.rs
@@ -0,0 +1,50 @@
+//! Late-metadata archive member that lists which rlib entries are Rust object files,
+//! replacing the `looks_like_rust_object_file` filename heuristic.
+//! See <https://github.com/rust-lang/rust/issues/138243>.
+
+use std::path::Path;
+
+use object::read::archive::ArchiveFile;
+use rustc_serialize::opaque::mem_encoder::MemEncoder;
+use rustc_serialize::opaque::{MAGIC_END_BYTES, MemDecoder};
+use rustc_serialize::{Decodable, Encodable};
+
+use super::metadata::search_for_section;
+
+pub(crate) const FILENAME: &str = "lib.rmeta-link";
+pub(crate) const SECTION: &str = ".rmeta-link";
+
+pub(crate) struct RmetaLink {
+    pub rust_object_files: Vec<String>,
+}
+
+impl RmetaLink {
+    pub(crate) fn encode(&self) -> Vec<u8> {
+        let mut encoder = MemEncoder::new();
+        self.rust_object_files.encode(&mut encoder);
+        let mut data = encoder.finish();
+        data.extend_from_slice(MAGIC_END_BYTES);
+        data
+    }
+
+    pub(crate) fn decode(data: &[u8]) -> Option<RmetaLink> {
+        let mut decoder = MemDecoder::new(data, 0).ok()?;
+        let rust_object_files = Vec::<String>::decode(&mut decoder);
+        Some(RmetaLink { rust_object_files })
+    }
+}
+
+/// Reads the digest from already-mapped archive data.
+pub(crate) fn read(archive_data: &[u8], rlib_path: &Path) -> Option<RmetaLink> {
+    let archive = ArchiveFile::parse(archive_data).ok()?;
+
+    for entry in archive.members() {
+        let entry = entry.ok()?;
+        if entry.name() == FILENAME.as_bytes() {
+            let data = entry.data(archive_data).ok()?;
+            let section_data = search_for_section(rlib_path, data, SECTION).ok()?;
+            return RmetaLink::decode(section_data);
+        }
+    }
+    None
+}