diff --git a/compiler/rustc_codegen_llvm/src/back/archive.rs b/compiler/rustc_codegen_llvm/src/back/archive.rs
index e73e122ee68d..9be104fde6c4 100644
--- a/compiler/rustc_codegen_llvm/src/back/archive.rs
+++ b/compiler/rustc_codegen_llvm/src/back/archive.rs
@@ -13,7 +13,8 @@ use object::read::macho::FatArch;
 
 use crate::common;
 use crate::errors::{
-    ArchiveBuildFailure, ErrorCallingDllTool, ErrorCreatingImportLibrary, ErrorWritingDEFFile,
+    ArchiveBuildFailure, DlltoolFailImportLibrary, ErrorCallingDllTool, ErrorCreatingImportLibrary,
+    ErrorWritingDEFFile,
 };
 use crate::llvm::archive_ro::{ArchiveRO, Child};
 use crate::llvm::{self, ArchiveKind, LLVMMachineType, LLVMRustCOFFShortExport};
@@ -244,11 +245,12 @@ impl ArchiveBuilderBuilder for LlvmArchiveBuilderBuilder {
                 Err(e) => {
                     sess.emit_fatal(ErrorCallingDllTool { error: e });
                 }
-                Ok(output) if !output.status.success() => sess.fatal(&format!(
-                    "Dlltool could not create import library: {}\n{}",
-                    String::from_utf8_lossy(&output.stdout),
-                    String::from_utf8_lossy(&output.stderr)
-                )),
+                Ok(output) if !output.status.success() => {
+                    sess.emit_fatal(DlltoolFailImportLibrary {
+                        stdout: String::from_utf8_lossy(&output.stdout),
+                        stderr: String::from_utf8_lossy(&output.stderr),
+                    })
+                }
                 _ => {}
             }
         } else {
diff --git a/compiler/rustc_codegen_llvm/src/errors.rs b/compiler/rustc_codegen_llvm/src/errors.rs
index 4856cead1521..68c2e6928304 100644
--- a/compiler/rustc_codegen_llvm/src/errors.rs
+++ b/compiler/rustc_codegen_llvm/src/errors.rs
@@ -1,3 +1,5 @@
+use std::borrow::Cow;
+
 use rustc_errors::fluent;
 use rustc_errors::DiagnosticBuilder;
 use rustc_macros::SessionDiagnostic;
@@ -102,3 +104,10 @@ pub(crate) struct ErrorWritingDEFFile {
 pub(crate) struct ErrorCallingDllTool {
     pub error: std::io::Error,
 }
+
+#[derive(SessionDiagnostic)]
+#[diag(codegen_llvm::dlltool_fail_import_library)]
+pub(crate) struct DlltoolFailImportLibrary<'a> {
+    pub stdout: Cow<'a, str>,
+    pub stderr: Cow<'a, str>,
+}
diff --git a/compiler/rustc_error_messages/locales/en-US/codegen_llvm.ftl b/compiler/rustc_error_messages/locales/en-US/codegen_llvm.ftl
index 3c8a893b4a5a..f9266b54d137 100644
--- a/compiler/rustc_error_messages/locales/en-US/codegen_llvm.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/codegen_llvm.ftl
@@ -45,3 +45,6 @@ codegen_llvm_error_writing_def_file =
 
 codegen_llvm_error_calling_dlltool =
     Error calling dlltool: {$error}
+
+codegen_llvm_dlltool_fail_import_library =
+    Dlltool could not create import library: {$stdout}\n{$stderr}
diff --git a/compiler/rustc_errors/src/diagnostic_impls.rs b/compiler/rustc_errors/src/diagnostic_impls.rs
index 22f6fc700fad..c6035705e39f 100644
--- a/compiler/rustc_errors/src/diagnostic_impls.rs
+++ b/compiler/rustc_errors/src/diagnostic_impls.rs
@@ -107,6 +107,12 @@ impl IntoDiagnosticArg for String {
     }
 }
 
+impl<'a> IntoDiagnosticArg for Cow<'a, str> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.into_owned()))
+    }
+}
+
 impl<'a> IntoDiagnosticArg for &'a Path {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
         DiagnosticArgValue::Str(Cow::Owned(self.display().to_string()))