diff --git a/lld/ELF/Config.h b/lld/ELF/Config.h
--- a/lld/ELF/Config.h
+++ b/lld/ELF/Config.h
@@ -196,6 +196,7 @@
   bool warnMissingEntry;
   bool warnSymbolOrdering;
   bool writeAddends;
+  bool mmapOutputFile;
   bool zCombreloc;
   bool zCopyreloc;
   bool zExecstack;
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -947,6 +947,8 @@
       args.hasFlag(OPT_warn_ifunc_textrel, OPT_no_warn_ifunc_textrel, false);
   config->warnSymbolOrdering =
       args.hasFlag(OPT_warn_symbol_ordering, OPT_no_warn_symbol_ordering, true);
+  config->mmapOutputFile =
+      args.hasFlag(OPT_mmap_output_file, OPT_no_mmap_output_file, true);
   config->zCombreloc = getZFlag(args, "combreloc", "nocombreloc", true);
   config->zCopyreloc = getZFlag(args, "copyreloc", "nocopyreloc", true);
   config->zExecstack = getZFlag(args, "execstack", "noexecstack", false);
diff --git a/lld/ELF/Options.td b/lld/ELF/Options.td
--- a/lld/ELF/Options.td
+++ b/lld/ELF/Options.td
@@ -406,6 +406,10 @@
     "Warn about problems with the symbol ordering file (default)",
     "Do not warn about problems with the symbol ordering file">;
 
+defm mmap_output_file: B<"mmap-output-file",
+    "Map the output file for writing (default)",
+    "Do not map the output file for writing">;
+
 def warn_unresolved_symbols: F<"warn-unresolved-symbols">,
   HelpText<"Report unresolved symbols as warnings">;
 
@@ -566,7 +570,6 @@
 def: F<"no-copy-dt-needed-entries">;
 def: F<"no-ctors-in-init-array">;
 def: F<"no-keep-memory">;
-def: F<"no-mmap-output-file">;
 def: F<"no-pipeline-knowledge">;
 def: F<"no-warn-mismatch">;
 def: Flag<["-"], "p">;
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -2594,6 +2594,8 @@
   unsigned flags = 0;
   if (!config->relocatable)
     flags = FileOutputBuffer::F_executable;
+  if (!config->mmapOutputFile)
+    flags |= FileOutputBuffer::F_in_memory;
   Expected<std::unique_ptr<FileOutputBuffer>> bufferOrErr =
       FileOutputBuffer::create(config->outputFile, fileSize, flags);
 
diff --git a/lld/test/ELF/mmap-output-file.s b/lld/test/ELF/mmap-output-file.s
new file mode 100644
--- /dev/null
+++ b/lld/test/ELF/mmap-output-file.s
@@ -0,0 +1,14 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
+# RUN: ld.lld %t.o -mmap-output-file -o %t1
+# RUN: llvm-objdump -d %t1 | FileCheck %s
+
+# CHECK: nop
+
+# RUN: ld.lld %t.o -no-mmap-output-file -o %t2
+# RUN: diff %t1 %t2
+
+.globl _start
+_start:
+  nop
diff --git a/lld/test/ELF/silent-ignore.test b/lld/test/ELF/silent-ignore.test
--- a/lld/test/ELF/silent-ignore.test
+++ b/lld/test/ELF/silent-ignore.test
@@ -6,7 +6,6 @@
 RUN:   -no-copy-dt-needed-entries \
 RUN:   -no-ctors-in-init-array \
 RUN:   -no-keep-memory \
-RUN:   -no-mmap-output-file \
 RUN:   -no-pipeline-knowledge \
 RUN:   -no-warn-mismatch \
 RUN:   -p \