diff --git a/llvm/test/tools/llvm-objcopy/ELF/mirror-permissions-unix.test b/llvm/test/tools/llvm-objcopy/ELF/mirror-permissions-unix.test
--- a/llvm/test/tools/llvm-objcopy/ELF/mirror-permissions-unix.test
+++ b/llvm/test/tools/llvm-objcopy/ELF/mirror-permissions-unix.test
@@ -26,16 +26,22 @@
 # RUN: llvm-objcopy %t %t1
 # RUN: ls -l %t1 | cut -f 1 -d ' ' > %t1.perms
 # RUN: cmp %t1.perms %t.0777
+# RUN: llvm-objcopy %t
+# RUN: ls -l %t1 | cut -f 1 -d ' ' | cmp %t.0777 -
 
 # RUN: chmod 0666 %t
 # RUN: llvm-objcopy %t %t1
 # RUN: ls -l %t1 | cut -f 1 -d ' ' > %t1.perms
 # RUN: cmp %t1.perms %t.0666
+# RUN: llvm-objcopy %t
+# RUN: ls -l %t1 | cut -f 1 -d ' ' | cmp %t.0666 -
 
 # RUN: chmod 0640 %t
 # RUN: llvm-objcopy %t %t1
 # RUN: ls -l %t1 | cut -f 1 -d ' ' > %t1.perms
 # RUN: cmp %t1.perms %t.0640
+# RUN: llvm-objcopy %t
+# RUN: ls -l %t1 | cut -f 1 -d ' ' | cmp %t.0640 -
 
 ## Don't set the permission of a character special file, otherwise there will
 ## be an EPERM error (or worse: root may change the permission).
diff --git a/llvm/tools/llvm-objcopy/llvm-objcopy.cpp b/llvm/tools/llvm-objcopy/llvm-objcopy.cpp
--- a/llvm/tools/llvm-objcopy/llvm-objcopy.cpp
+++ b/llvm/tools/llvm-objcopy/llvm-objcopy.cpp
@@ -228,9 +228,21 @@
                           Config.DeterministicArchives, Ar.isThin());
 }
 
+static Error createOrOverwrite(StringRef Filename, ArrayRef<char> Buf) {
+  int FD;
+  std::error_code EC;
+  if (auto EC = sys::fs::openFileForWrite(
+          Filename, FD, sys::fs::CD_CreateAlways, sys::fs::OF_None,
+          sys::fs::all_read | sys::fs::all_write))
+    return errorCodeToError(EC);
+  raw_fd_ostream(FD, /*shouldClose=*/true, /*unbuffered=*/true)
+      << StringRef(Buf.data(), Buf.size());
+  return Error::success();
+}
+
 static Error restoreStatOnFile(StringRef Filename,
                                const sys::fs::file_status &Stat,
-                               bool PreserveDates) {
+                               bool PreserveDates, bool PreserveModes) {
   int FD;
 
   // Writing to stdout should not be treated as an error here, just
@@ -247,20 +259,22 @@
             FD, Stat.getLastAccessedTime(), Stat.getLastModificationTime()))
       return createFileError(Filename, EC);
 
-  sys::fs::file_status OStat;
-  if (std::error_code EC = sys::fs::status(FD, OStat))
-    return createFileError(Filename, EC);
-  if (OStat.type() == sys::fs::file_type::regular_file)
+  if (PreserveModes) {
+    sys::fs::file_status OStat;
+    if (std::error_code EC = sys::fs::status(FD, OStat))
+      return createFileError(Filename, EC);
+    if (OStat.type() == sys::fs::file_type::regular_file)
 #ifdef _WIN32
-    if (auto EC = sys::fs::setPermissions(
-            Filename, static_cast<sys::fs::perms>(Stat.permissions() &
-                                                  ~sys::fs::getUmask())))
+      if (auto EC = sys::fs::setPermissions(
+              Filename, static_cast<sys::fs::perms>(Stat.permissions() &
+                                                    ~sys::fs::getUmask())))
 #else
-    if (auto EC = sys::fs::setPermissions(
-            FD, static_cast<sys::fs::perms>(Stat.permissions() &
-                                            ~sys::fs::getUmask())))
+      if (auto EC = sys::fs::setPermissions(
+              FD, static_cast<sys::fs::perms>(Stat.permissions() &
+                                              ~(sys::fs::getUmask() | 06000))))
 #endif
-      return createFileError(Filename, EC);
+        return createFileError(Filename, EC);
+  }
 
   if (auto EC = sys::Process::SafelyCloseFileDescriptor(FD))
     return createFileError(Filename, EC);
@@ -293,6 +307,7 @@
     ProcessRaw = nullptr;
   }
 
+  bool PreserveModes = true;
   if (ProcessRaw) {
     auto BufOrErr = MemoryBuffer::getFileOrSTDIN(Config.InputFilename);
     if (!BufOrErr)
@@ -309,6 +324,23 @@
     if (Archive *Ar = dyn_cast<Archive>(BinaryOrErr.get().getBinary())) {
       if (Error E = executeObjcopyOnArchive(Config, *Ar))
         return E;
+    } else if (Config.InputFilename == Config.OutputFilename &&
+               Config.InputFilename != "-" && !Config.BuildIdLinkInput &&
+               !Config.BuildIdLinkOutput) {
+      // If input filename = output filename, create an in-memory buffer and
+      // overwrite the input instead of atomic rename to avoid owner/group/mode
+      // changes. --build-id-link-{input,output} need the on-disk file, so
+      // overwrite cannot be used.
+      MemBuffer MB(Config.OutputFilename);
+      if (Error E = executeObjcopyOnBinary(Config,
+                                           *BinaryOrErr.get().getBinary(), MB))
+        return E;
+      std::unique_ptr<WritableMemoryBuffer> WMB = MB.releaseMemoryBuffer();
+      // Release the existing handle before overwriting.
+      (void)BinaryOrErr->takeBinary();
+      if (Error E = createOrOverwrite(Config.InputFilename, WMB->getBuffer()))
+        return E;
+      PreserveModes = false;
     } else {
       FileBuffer FB(Config.OutputFilename);
       if (Error E = executeObjcopyOnBinary(Config,
@@ -317,14 +349,14 @@
     }
   }
 
-  if (Error E =
-          restoreStatOnFile(Config.OutputFilename, Stat, Config.PreserveDates))
+  if (Error E = restoreStatOnFile(Config.OutputFilename, Stat,
+                                  Config.PreserveDates, PreserveModes))
     return E;
 
   if (!Config.SplitDWO.empty()) {
     Stat.permissions(static_cast<sys::fs::perms>(0666));
-    if (Error E =
-            restoreStatOnFile(Config.SplitDWO, Stat, Config.PreserveDates))
+    if (Error E = restoreStatOnFile(Config.SplitDWO, Stat, Config.PreserveDates,
+                                    true))
       return E;
   }