diff --git a/include/llvm/ObjectYAML/ArchiveYAML.h b/include/llvm/ObjectYAML/ArchiveYAML.h
new file mode 100644
index 00000000000..8d05feedcc6
--- /dev/null
+++ b/include/llvm/ObjectYAML/ArchiveYAML.h
@@ -0,0 +1,77 @@
+//===- ArchiveYAML.h - Archive YAMLIO implementation ------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file declares classes for handling the YAML representation of archives.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_OBJECTYAML_ARCHIVEYAML_H
+#define LLVM_OBJECTYAML_ARCHIVEYAML_H
+
+#include "llvm/Support/YAMLTraits.h"
+#include "llvm/ObjectYAML/YAML.h"
+#include "llvm/ADT/MapVector.h"
+
+namespace llvm {
+namespace ArchYAML {
+
+struct Archive {
+  struct Child {
+    struct Field {
+      Field() = default;
+      Field(StringRef Default, unsigned Length)
+          : DefaultValue(Default), MaxLength(Length) {}
+      StringRef Value;
+      StringRef DefaultValue;
+      unsigned MaxLength;
+    };
+
+    Child() {
+      Fields["Name"] = {"", 16};
+      Fields["LastModified"] = {"0", 12};
+      Fields["UID"] = {"0", 6};
+      Fields["GID"] = {"0", 6};
+      Fields["AccessMode"] = {"0", 8};
+      Fields["Size"] = {"0", 10};
+      Fields["Terminator"] = {"`\n", 2};
+    }
+
+    MapVector<StringRef, Field> Fields;
+
+    Optional<yaml::BinaryRef> Content;
+    Optional<llvm::yaml::Hex8> PaddingByte;
+  };
+
+  StringRef Magic;
+  Optional<std::vector<Child>> Members;
+  Optional<yaml::BinaryRef> Content;
+};
+
+} // end namespace ArchYAML
+} // end namespace llvm
+
+LLVM_YAML_IS_SEQUENCE_VECTOR(llvm::ArchYAML::Archive::Child)
+
+namespace llvm {
+namespace yaml {
+
+template <> struct MappingTraits<ArchYAML::Archive> {
+  static void mapping(IO &IO, ArchYAML::Archive &A);
+  static std::string validate(IO &, ArchYAML::Archive &A);
+};
+
+template <> struct MappingTraits<ArchYAML::Archive::Child> {
+  static void mapping(IO &IO, ArchYAML::Archive::Child &C);
+  static std::string validate(IO &, ArchYAML::Archive::Child &C);
+};
+
+} // end namespace yaml
+} // end namespace llvm
+
+#endif // LLVM_OBJECTYAML_ARCHIVEYAML_H
diff --git a/include/llvm/ObjectYAML/ObjectYAML.h b/include/llvm/ObjectYAML/ObjectYAML.h
index 0015fd3dc50..dd26ce3e970 100644
--- a/include/llvm/ObjectYAML/ObjectYAML.h
+++ b/include/llvm/ObjectYAML/ObjectYAML.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_OBJECTYAML_OBJECTYAML_H
 #define LLVM_OBJECTYAML_OBJECTYAML_H
 
+#include "llvm/ObjectYAML/ArchiveYAML.h"
 #include "llvm/ObjectYAML/COFFYAML.h"
 #include "llvm/ObjectYAML/ELFYAML.h"
 #include "llvm/ObjectYAML/MachOYAML.h"
@@ -23,6 +24,7 @@ namespace yaml {
 class IO;
 
 struct YamlObjectFile {
+  std::unique_ptr<ArchYAML::Archive> Arch;
   std::unique_ptr<ELFYAML::Object> Elf;
   std::unique_ptr<COFFYAML::Object> Coff;
   std::unique_ptr<MachOYAML::Object> MachO;
diff --git a/include/llvm/ObjectYAML/yaml2obj.h b/include/llvm/ObjectYAML/yaml2obj.h
index 34def363a55..1f693475c94 100644
--- a/include/llvm/ObjectYAML/yaml2obj.h
+++ b/include/llvm/ObjectYAML/yaml2obj.h
@@ -40,12 +40,17 @@ namespace WasmYAML {
 struct Object;
 }
 
+namespace ArchYAML {
+struct Archive;
+}
+
 namespace yaml {
 class Input;
 struct YamlObjectFile;
 
 using ErrorHandler = llvm::function_ref<void(const Twine &Msg)>;
 
+bool yaml2archive(ArchYAML::Archive &Doc, raw_ostream &Out, ErrorHandler EH);
 bool yaml2coff(COFFYAML::Object &Doc, raw_ostream &Out, ErrorHandler EH);
 bool yaml2elf(ELFYAML::Object &Doc, raw_ostream &Out, ErrorHandler EH,
               uint64_t MaxSize);
diff --git a/lib/ObjectYAML/ArchiveEmitter.cpp b/lib/ObjectYAML/ArchiveEmitter.cpp
new file mode 100644
index 00000000000..a0cf8fe360d
--- /dev/null
+++ b/lib/ObjectYAML/ArchiveEmitter.cpp
@@ -0,0 +1,51 @@
+//===- ArchiveEmitter.cpp ---------------------------- --------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ObjectYAML/ArchiveYAML.h"
+#include "llvm/ObjectYAML/yaml2obj.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+using namespace ArchYAML;
+
+namespace llvm {
+namespace yaml {
+
+bool yaml2archive(ArchYAML::Archive &Doc, raw_ostream &Out, ErrorHandler EH) {
+  Out.write(Doc.Magic.data(), Doc.Magic.size());
+
+  if (Doc.Content) {
+    Doc.Content->writeAsBinary(Out);
+    return true;
+  }
+
+  if (!Doc.Members)
+    return true;
+
+  auto WriteField = [&](StringRef Field, uint8_t Size) {
+    Out.write(Field.data(), Field.size());
+    for (size_t I = Field.size(); I != Size; ++I)
+      Out.write(' ');
+  };
+
+  for (const Archive::Child &C : *Doc.Members) {
+    for (auto &P : C.Fields)
+      WriteField(P.second.Value, P.second.MaxLength);
+
+    if (C.Content)
+      C.Content->writeAsBinary(Out);
+    if (C.PaddingByte)
+      Out.write(*C.PaddingByte);
+  }
+
+  return true;
+}
+
+} // namespace yaml
+} // namespace llvm
diff --git a/lib/ObjectYAML/ArchiveYAML.cpp b/lib/ObjectYAML/ArchiveYAML.cpp
new file mode 100644
index 00000000000..d2ea1eaf521
--- /dev/null
+++ b/lib/ObjectYAML/ArchiveYAML.cpp
@@ -0,0 +1,58 @@
+//===- ArchiveYAML.cpp - ELF YAMLIO implementation -------------------- ----===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines classes for handling the YAML representation of archives.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ObjectYAML/ArchiveYAML.h"
+
+namespace llvm {
+
+namespace yaml {
+
+void MappingTraits<ArchYAML::Archive>::mapping(IO &IO, ArchYAML::Archive &A) {
+  assert(!IO.getContext() && "The IO context is initialized already");
+  IO.setContext(&A);
+  IO.mapTag("!Arch", true);
+  IO.mapOptional("Magic", A.Magic, "!<arch>\n");
+  IO.mapOptional("Members", A.Members);
+  IO.mapOptional("Content", A.Content);
+  IO.setContext(nullptr);
+}
+
+std::string MappingTraits<ArchYAML::Archive>::validate(IO &,
+                                                       ArchYAML::Archive &A) {
+  if (A.Members && A.Content)
+    return "\"Content\" and \"Members\" cannot be used together";
+  return "";
+}
+
+void MappingTraits<ArchYAML::Archive::Child>::mapping(
+    IO &IO, ArchYAML::Archive::Child &E) {
+  assert(IO.getContext() && "The IO context is not initialized");
+  for (auto &P : E.Fields)
+    IO.mapOptional(P.first.data(), P.second.Value, P.second.DefaultValue);
+  IO.mapOptional("Content", E.Content);
+  IO.mapOptional("PaddingByte", E.PaddingByte);
+}
+
+std::string
+MappingTraits<ArchYAML::Archive::Child>::validate(IO &,
+                                                  ArchYAML::Archive::Child &C) {
+  for (auto &P : C.Fields)
+    if (P.second.Value.size() > P.second.MaxLength)
+      return ("the maximum length of \"" + P.first + "\" field is " +
+              Twine(P.second.MaxLength))
+          .str();
+  return "";
+}
+
+} // end namespace yaml
+
+} // end namespace llvm
diff --git a/lib/ObjectYAML/CMakeLists.txt b/lib/ObjectYAML/CMakeLists.txt
index 92ea1ec9866..a024fa96535 100644
--- a/lib/ObjectYAML/CMakeLists.txt
+++ b/lib/ObjectYAML/CMakeLists.txt
@@ -1,4 +1,6 @@
 add_llvm_component_library(LLVMObjectYAML
+  ArchiveEmitter.cpp
+  ArchiveYAML.cpp
   CodeViewYAMLDebugSections.cpp
   CodeViewYAMLSymbols.cpp
   CodeViewYAMLTypeHashing.cpp
diff --git a/lib/ObjectYAML/ObjectYAML.cpp b/lib/ObjectYAML/ObjectYAML.cpp
index 7f636f4eaba..4564b537c9a 100644
--- a/lib/ObjectYAML/ObjectYAML.cpp
+++ b/lib/ObjectYAML/ObjectYAML.cpp
@@ -33,7 +33,14 @@ void MappingTraits<YamlObjectFile>::mapping(IO &IO,
                                                          *ObjectFile.FatMachO);
   } else {
     Input &In = (Input &)IO;
-    if (IO.mapTag("!ELF")) {
+    if (IO.mapTag("!Arch")) {
+      ObjectFile.Arch.reset(new ArchYAML::Archive());
+      MappingTraits<ArchYAML::Archive>::mapping(IO, *ObjectFile.Arch);
+      std::string Err =
+          MappingTraits<ArchYAML::Archive>::validate(IO, *ObjectFile.Arch);
+      if (!Err.empty())
+        IO.setError(Err);
+    } else if (IO.mapTag("!ELF")) {
       ObjectFile.Elf.reset(new ELFYAML::Object());
       MappingTraits<ELFYAML::Object>::mapping(IO, *ObjectFile.Elf);
     } else if (IO.mapTag("!COFF")) {
diff --git a/lib/ObjectYAML/yaml2obj.cpp b/lib/ObjectYAML/yaml2obj.cpp
index a04345f1294..ef2ab83dcd2 100644
--- a/lib/ObjectYAML/yaml2obj.cpp
+++ b/lib/ObjectYAML/yaml2obj.cpp
@@ -32,6 +32,8 @@ bool convertYAML(yaml::Input &YIn, raw_ostream &Out, ErrorHandler ErrHandler,
       return false;
     }
 
+    if (Doc.Arch)
+      return yaml2archive(*Doc.Arch, Out, ErrHandler);
     if (Doc.Elf)
       return yaml2elf(*Doc.Elf, Out, ErrHandler, MaxSize);
     if (Doc.Coff)
diff --git a/test/tools/obj2yaml/Archives/regular.yaml b/test/tools/obj2yaml/Archives/regular.yaml
new file mode 100644
index 00000000000..8b2969fdb10
--- /dev/null
+++ b/test/tools/obj2yaml/Archives/regular.yaml
@@ -0,0 +1,158 @@
+## Check how obj2yaml dumps regular archives.
+
+## Check how we dump an empty archive.
+
+# RUN: rm -f %t.empty.a
+# RUN: llvm-ar rc %t.empty.a
+# RUN: obj2yaml %t.empty.a | FileCheck %s --check-prefix=EMPTY
+
+# EMPTY:      --- !Arch
+# EMPTY-NEXT: Members: []
+# EMPTY-NEXT: ...
+
+## Check how we dump archives with multiple members.
+## Check we don't dump excessive spaces when dumping fields.
+## Check we don't dump fields with values that are equal to default values.
+## Check how we dump empty field values.
+
+# RUN: yaml2obj %s --docnum=1 -o %t.multiple.a
+# RUN: obj2yaml %t.multiple.a | FileCheck %s --check-prefix=MULTIPLE
+
+# MULTIPLE:      --- !Arch
+# MULTIPLE-NEXT: Members:
+# MULTIPLE-NEXT:   - Name:         'bbb/'
+# MULTIPLE-NEXT:     LastModified: '1'
+# MULTIPLE-NEXT:     UID:          '2'
+# MULTIPLE-NEXT:     GID:          '3'
+# MULTIPLE-NEXT:     AccessMode:   '644'
+# MULTIPLE-NEXT:     Size:         '6'
+# MULTIPLE-NEXT:     Content:      20616161200A
+# MULTIPLE-NEXT:   - Name:         'dddd/'
+# MULTIPLE-NEXT:     LastModified: '4'
+# MULTIPLE-NEXT:     UID:          '5'
+# MULTIPLE-NEXT:     GID:          '6'
+# MULTIPLE-NEXT:     AccessMode:   '987'
+# MULTIPLE-NEXT:     Size:         '7'
+# MULTIPLE-NEXT:     Content:      2063636363200A
+# MULTIPLE-NEXT:     PaddingByte:  0x0A
+# MULTIPLE-NEXT:   - LastModified: ''
+# MULTIPLE-NEXT:     UID:          ''
+# MULTIPLE-NEXT:     GID:          ''
+# MULTIPLE-NEXT:     AccessMode:   ''
+# MULTIPLE-NEXT:     Terminator:   ''
+# MULTIPLE-NEXT:     Content:      ''
+# MULTIPLE-NEXT:   - {}
+# MULTIPLE-NEXT: ...
+
+--- !Arch
+Members:
+  - Name:         'bbb/'
+    LastModified: '1'
+    UID:          '2'
+    GID:          '3'
+    AccessMode:   '644'
+    Size:         '6'
+    Terminator:   "`\n"
+    Content:      20616161200A ## " aaa \n"
+  - Name:         'dddd/'
+    LastModified: '4'
+    UID:          '5'
+    GID:          '6'
+    AccessMode:   '987'
+    Size:         '7'
+    Terminator:   "`\n"
+    Content:      2063636363200A ## " cccc \n"
+    PaddingByte:  0x0A
+## All fields are empty (where possible).
+  - Name:         ''
+    LastModified: ''
+    UID:          ''
+    GID:          ''
+    AccessMode:   ''
+    Size:         '0'
+    Terminator:   ''
+    Content:      ''
+## All fields are explicitly set to the default values.
+  - Name:         ''
+    LastModified: '0'
+    UID:          '0'
+    GID:          '0'
+    AccessMode:   '0'
+    Size:         '0'
+    Terminator:   "`\n"
+    Content:      ""
+...
+
+## Check we report an error for non-regular archives.
+
+# RUN: yaml2obj %s --docnum=2 -o %t.not.regular.a
+# RUN: not obj2yaml %t.not.regular.a 2>&1 | \
+# RUN:   FileCheck %s -DFILE=%t.not.regular.a --check-prefix=NOT-REGULAR-ERR
+
+# NOT-REGULAR-ERR: Error reading file: [[FILE]]: only regular archives are supported
+
+--- !Arch
+Magic: "!<thin>\n"
+Members:
+  - {}
+
+## Check we report an error when unable to read the header of an archive member.
+
+# RUN: yaml2obj %s --docnum=3 -o %t.truncated.a
+# RUN: not obj2yaml %t.truncated.a 2>&1 | \
+# RUN:   FileCheck %s -DFILE=%t.truncated.a --check-prefix=TRUNCATED-ERR
+
+# TRUNCATED-ERR: Error reading file: [[FILE]]: unable to read the header of a child at offset 0x8
+
+--- !Arch
+Content: "00"
+
+## Check we report an error when unable to read the data of an archive member.
+
+# RUN: yaml2obj %s --docnum=4 -o %t.entdata.a
+# RUN: not obj2yaml %t.entdata.a 2>&1 | \
+# RUN:   FileCheck %s -DFILE=%t.entdata.a --check-prefix=ENTDATA-ERR
+
+# ENTDATA-ERR: Error reading file: [[FILE]]: unable to read the data of a child at offset 0x8 of size 1: the remaining archive size is 0
+
+--- !Arch
+Members:
+  - Size: [[SIZE='1']]
+
+## Check we report an error when unable to read the size of an archive member.
+
+# RUN: yaml2obj %s --docnum=4 -DSIZE='x' -o %t.entsize.a
+# RUN: not obj2yaml %t.entsize.a 2>&1 | \
+# RUN:   FileCheck %s -DFILE=%t.entsize.a --check-prefix=ENTSIZE-ERR
+
+# ENTSIZE-ERR: Error reading file: [[FILE]]: unable to read the size of a child at offset 0x8 as integer: "x"
+
+## Check we don't try to dump the padding byte when the size of the content is odd and
+## the content ends at the end of a file.
+
+# RUN: yaml2obj %s --docnum=5 -DCONTENT="61" -o %t.no.padding.byte.a
+# RUN: obj2yaml %t.no.padding.byte.a | FileCheck %s --check-prefix=NO-PADDING-BYTE
+
+#      NO-PADDING-BYTE: --- !Arch
+# NO-PADDING-BYTE-NEXT: Members:
+# NO-PADDING-BYTE-NEXT:   - Size:    '1'
+# NO-PADDING-BYTE-NEXT:     Content: '61'
+# NO-PADDING-BYTE-NEXT: ...
+
+--- !Arch
+Members:
+  - Size:    '1'
+    Content: [[CONTENT]]
+
+## Check we dump the padding byte when the size of the content is odd and the content ends
+## before the end of a file.
+
+# RUN: yaml2obj %s --docnum=5 -DCONTENT="610A" -o %t.padding.byte.a
+# RUN: obj2yaml %t.padding.byte.a | FileCheck %s --check-prefix=PADDING-BYTE
+
+#      PADDING-BYTE: --- !Arch
+# PADDING-BYTE-NEXT: Members:
+# PADDING-BYTE-NEXT:   - Size:        '1'
+# PADDING-BYTE-NEXT:     Content:     '61'
+# PADDING-BYTE-NEXT:     PaddingByte: 0x0A
+# PADDING-BYTE-NEXT: ...
diff --git a/test/tools/yaml2obj/Archives/regular.yaml b/test/tools/yaml2obj/Archives/regular.yaml
new file mode 100644
index 00000000000..29b0cb5eea8
--- /dev/null
+++ b/test/tools/yaml2obj/Archives/regular.yaml
@@ -0,0 +1,132 @@
+## Check how yaml2obj creates archives.
+
+## Check we create an empty archive when neither "Members" nor "Content" are specified.
+
+# RUN: yaml2obj --docnum=1 %s -o %t.empty.a
+# RUN: llvm-ar t %t.empty.a | FileCheck %s --allow-empty --implicit-check-not={{.}}
+# RUN: wc -c < %t.empty.a | FileCheck %s --check-prefix=EMPTY-SIZE
+# RUN: od -t x1 -v %t.empty.a | FileCheck %s --ignore-case --check-prefix=EMPTY-DATA
+
+# EMPTY-SIZE: 8{{$}}
+# EMPTY-DATA: 21 3c 61 72 63 68 3e 0a
+
+--- !Arch
+Magic:   "[[MAGIC=!<arch>\n]]"
+Content: [[CONTENT=<none>]]
+Members: [[MEMBERS=<none>]]
+
+## Check we report an error when both "Content" and "Members" keys are used together.
+
+# RUN: not yaml2obj --docnum=1 -DMEMBERS="[]" -DCONTENT="00" %s 2>&1 | FileCheck %s --check-prefix=BOTH
+
+## BOTH: error: "Content" and "Members" cannot be used together
+
+# RUN: yaml2obj --docnum=1 -DCONTENT="12" %s -o %t.content.a
+# RUN: od -t x1 -v %t.content.a | FileCheck %s --ignore-case --check-prefix=CONTENT
+
+# CONTENT: 21 3c 61 72 63 68 3e 0a 12{{$}}
+
+## Check we can specify magic bytes of size greater than the normal size (size of "!<arch>\n").
+
+# RUN: yaml2obj --docnum=1 -DMAGIC="123456789" %s -o %t.magic2.a
+# RUN: wc -c < %t.magic2.a | FileCheck %s --check-prefix=MAGIC-SIZE-GR
+# RUN: od -t x1 -v %t.magic2.a | FileCheck %s --ignore-case --check-prefix=MAGIC-DATA-GR
+
+# MAGIC-SIZE-GR: 9{{$}}
+# MAGIC-DATA-GR: 31 32 33 34 35 36 37 38 39
+
+## Check we can specify magic bytes of size less than the normal size (size of "!<arch>\n").
+
+# RUN: yaml2obj --docnum=1 -DMAGIC="1234567" %s -o %t.magic3.a
+# RUN: wc -c < %t.magic3.a | FileCheck %s --check-prefix=MAGIC-SIZE-LESS
+# RUN: od -t x1 -v %t.magic3.a | FileCheck %s --ignore-case --check-prefix=MAGIC-DATA-LESS
+
+# MAGIC-SIZE-LESS: 7{{$}}
+# MAGIC-DATA-LESS: 31 32 33 34 35 36 37
+
+## Check we can produce a valid archive with multiple members.
+## Check we are able to omit the "Magic" key and this defaults to "!<arch>\n".
+
+# RUN: yaml2obj --docnum=2 %s -o %t.two.a
+# RUN: llvm-ar -t %t.two.a | FileCheck %s --check-prefix=TWO
+# RUN: FileCheck --input-file=%t.two.a %s \
+# RUN:   --match-full-lines --strict-whitespace --check-prefix=TWO-DATA
+
+# TWO:      {{^}}bbbbbbbbbbbbbbb{{$}}
+# TWO-NEXT: {{^}}a{{$}}
+# TWO-NOT:  {{.}}
+
+#      TWO-DATA:!<arch>
+# TWO-DATA-NEXT:bbbbbbbbbbbbbbb/1234567890abqwertyasdfgh876543217         `
+# TWO-DATA-NEXT: cccc {{$}}
+# TWO-DATA-NEXT:za/              1           2     3     456     6         `
+# TWO-DATA-NEXT: aaa {{$}}
+#  TWO-DATA-NOT:{{.}}
+
+--- !Arch
+Members:
+## An arbitrary entry where each of fields has maximum allowed length.
+  - Name:         'bbbbbbbbbbbbbbb/'
+    LastModified: '1234567890ab'
+    UID:          'qwerty'
+    GID:          'asdfgh'
+    AccessMode:   '87654321'
+    Size:         '7'
+    Terminator:   "`\n"
+    Content:      "2063636363200A"
+    PaddingByte:  0x7a ## 'z'
+## An arbitrary entry to demonstrate that we use the 0x20 byte (space character)
+## to fill gaps between field values.
+  - Name:         'a/'
+    LastModified: '1'
+    UID:          '2'
+    GID:          '3'
+    AccessMode:   '456'
+    Size:         '6'
+    Terminator:   "`\n"
+    Content:      "20616161200A"
+
+## Check how we validate maximum sizes of fields.
+
+# RUN: not yaml2obj --docnum=3 -DNAME="123456789ABCDEF01" %s 2>&1 | \
+# RUN:   FileCheck %s --check-prefix=ERROR -DFIELD="Name" -DVAL=16
+# RUN: not yaml2obj --docnum=3 -DLAST="123456789ABCD" %s 2>&1 | \
+# RUN:   FileCheck %s --check-prefix=ERROR -DFIELD="LastModified" -DVAL=12
+# RUN: not yaml2obj --docnum=3 -DUID="1234567" %s 2>&1 | \
+# RUN:   FileCheck %s --check-prefix=ERROR -DFIELD="UID" -DVAL=6
+# RUN: not yaml2obj --docnum=3 -DGID="1234567" %s 2>&1 | \
+# RUN:   FileCheck %s --check-prefix=ERROR -DFIELD="GID" -DVAL=6
+# RUN: not yaml2obj --docnum=3 -DACCESSMODE="123456789" %s 2>&1 | \
+# RUN:   FileCheck %s --check-prefix=ERROR -DFIELD="AccessMode" -DVAL=8
+# RUN: not yaml2obj --docnum=3 -DSIZE="123456789AB" %s 2>&1 | \
+# RUN:   FileCheck %s --check-prefix=ERROR -DFIELD="Size" -DVAL=10
+# RUN: not yaml2obj --docnum=3 -DTERMINATOR="123" %s 2>&1 | \
+# RUN:   FileCheck %s --check-prefix=ERROR -DFIELD="Terminator" -DVAL=2
+
+# ERROR: error: the maximum length of "[[FIELD]]" field is [[VAL]]
+
+--- !Arch
+Members:
+  - Name:         '[[NAME=""]]'
+    LastModified: '[[LAST=""]]'
+    UID:          '[[UID=""]]'
+    GID:          '[[GID=""]]'
+    AccessMode:   '[[ACCESSMODE=""]]'
+    Size:         '[[SIZE=""]]'
+    Terminator:   '[[TERMINATOR=""]]'
+
+## Check that all keys are optional for members.
+
+# RUN: yaml2obj --docnum=4 %s -o %t.all.defaults.a
+# RUN: FileCheck --input-file=%t.all.defaults.a %s \
+# RUN:   --match-full-lines --strict-whitespace --check-prefix=DEFAULTS
+
+#      DEFAULTS:!<arch>
+# DEFAULTS-NEXT:                0           0     0     0       0         `
+# DEFAULTS-NEXT:                0           0     0     0       0         `
+#  DEFAULTS-NOT:{{.}}
+
+--- !Arch
+Members:
+  - {}
+  - {}
diff --git a/tools/obj2yaml/CMakeLists.txt b/tools/obj2yaml/CMakeLists.txt
index 33cb36d9de4..9bd86a77dbe 100644
--- a/tools/obj2yaml/CMakeLists.txt
+++ b/tools/obj2yaml/CMakeLists.txt
@@ -8,6 +8,7 @@ set(LLVM_LINK_COMPONENTS
   )
 
 add_llvm_utility(obj2yaml
+  archive2yaml.cpp
   obj2yaml.cpp
   coff2yaml.cpp
   dwarf2yaml.cpp
diff --git a/tools/obj2yaml/archive2yaml.cpp b/tools/obj2yaml/archive2yaml.cpp
new file mode 100644
index 00000000000..c7b0ee48029
--- /dev/null
+++ b/tools/obj2yaml/archive2yaml.cpp
@@ -0,0 +1,114 @@
+//===------ utils/archive2yaml.cpp - obj2yaml conversion tool ---*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "obj2yaml.h"
+#include "llvm/BinaryFormat/Magic.h"
+#include "llvm/ObjectYAML/ArchiveYAML.h"
+
+using namespace llvm;
+
+namespace {
+
+class ArchiveDumper {
+public:
+  Expected<ArchYAML::Archive *> dump(MemoryBufferRef Source) {
+    StringRef Buffer = Source.getBuffer();
+    assert(file_magic::archive == identify_magic(Buffer));
+
+    std::unique_ptr<ArchYAML::Archive> Obj =
+        std::make_unique<ArchYAML::Archive>();
+
+    StringRef Magic = "!<arch>\n";
+    if (!Buffer.startswith(Magic))
+      return createStringError(std::errc::not_supported,
+                               "only regular archives are supported");
+    Obj->Magic = Magic;
+    Buffer = Buffer.drop_front(Magic.size());
+
+    Obj->Members.emplace();
+    while (!Buffer.empty()) {
+      uint64_t Offset = Buffer.data() - Source.getBuffer().data();
+      if (Buffer.size() < sizeof(ArchiveHeader))
+        return createStringError(
+            std::errc::illegal_byte_sequence,
+            "unable to read the header of a child at offset 0x%" PRIx64,
+            Offset);
+
+      const ArchiveHeader &Hdr =
+          *reinterpret_cast<const ArchiveHeader *>(Buffer.data());
+      Buffer = Buffer.drop_front(sizeof(ArchiveHeader));
+
+      auto ToString = [](ArrayRef<char> V) {
+        // We don't want to dump excessive spaces.
+        return StringRef(V.data(), V.size()).rtrim(' ');
+      };
+
+      ArchYAML::Archive::Child C;
+      C.Fields["Name"].Value = ToString(Hdr.Name);
+      C.Fields["LastModified"].Value = ToString(Hdr.LastModified);
+      C.Fields["UID"].Value = ToString(Hdr.UID);
+      C.Fields["GID"].Value = ToString(Hdr.GID);
+      C.Fields["AccessMode"].Value = ToString(Hdr.AccessMode);
+      StringRef SizeStr = ToString(Hdr.Size);
+      C.Fields["Size"].Value = SizeStr;
+      C.Fields["Terminator"].Value = ToString(Hdr.Terminator);
+
+      uint64_t Size;
+      if (SizeStr.getAsInteger(10, Size))
+        return createStringError(
+            std::errc::illegal_byte_sequence,
+            "unable to read the size of a child at offset 0x%" PRIx64
+            " as integer: \"%s\"",
+            Offset, SizeStr.str().c_str());
+      if (Buffer.size() < Size)
+        return createStringError(
+            std::errc::illegal_byte_sequence,
+            "unable to read the data of a child at offset 0x%" PRIx64
+            " of size %" PRId64 ": the remaining archive size is %zu",
+            Offset, Size, Buffer.size());
+      if (!Buffer.empty())
+        C.Content = arrayRefFromStringRef(Buffer.take_front(Size));
+
+      const bool HasPaddingByte = (Size & 1) && Buffer.size() > Size;
+      if (HasPaddingByte)
+        C.PaddingByte = Buffer[Size];
+
+      Obj->Members->push_back(C);
+      // If the size is odd, consume a padding byte.
+      Buffer = Buffer.drop_front(HasPaddingByte ? Size + 1 : Size);
+    }
+
+    return Obj.release();
+  }
+
+private:
+  struct ArchiveHeader {
+    char Name[16];
+    char LastModified[12];
+    char UID[6];
+    char GID[6];
+    char AccessMode[8];
+    char Size[10];
+    char Terminator[2];
+  };
+};
+
+} // namespace
+
+Error archive2yaml(raw_ostream &Out, MemoryBufferRef Source) {
+  ArchiveDumper Dumper;
+  Expected<ArchYAML::Archive *> YAMLOrErr = Dumper.dump(Source);
+  if (!YAMLOrErr)
+    return YAMLOrErr.takeError();
+
+  std::unique_ptr<ArchYAML::Archive> YAML(YAMLOrErr.get());
+  yaml::Output Yout(Out);
+  Yout << *YAML;
+
+  return Error::success();
+}
diff --git a/tools/obj2yaml/obj2yaml.cpp b/tools/obj2yaml/obj2yaml.cpp
index 16fc428755e..da70450503f 100644
--- a/tools/obj2yaml/obj2yaml.cpp
+++ b/tools/obj2yaml/obj2yaml.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "obj2yaml.h"
+#include "llvm/BinaryFormat/Magic.h"
 #include "llvm/Object/Archive.h"
 #include "llvm/Object/COFF.h"
 #include "llvm/Object/Minidump.h"
@@ -34,16 +35,26 @@ static Error dumpObject(const ObjectFile &Obj) {
 }
 
 static Error dumpInput(StringRef File) {
-  Expected<OwningBinary<Binary>> BinaryOrErr = createBinary(File);
-  if (!BinaryOrErr)
-    return BinaryOrErr.takeError();
+  ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
+      MemoryBuffer::getFileOrSTDIN(File, /*FileSize=*/-1,
+                                   /*RequiresNullTerminator=*/false);
+  if (std::error_code EC = FileOrErr.getError())
+    return errorCodeToError(EC);
+  std::unique_ptr<MemoryBuffer> &Buffer = FileOrErr.get();
+  MemoryBufferRef MemBuf = Buffer->getMemBufferRef();
+  if (file_magic::archive == identify_magic(MemBuf.getBuffer()))
+    return archive2yaml(outs(), MemBuf);
 
-  Binary &Binary = *BinaryOrErr.get().getBinary();
+  Expected<std::unique_ptr<Binary>> BinOrErr =
+      createBinary(MemBuf, /*Context=*/nullptr);
+  if (!BinOrErr)
+    return BinOrErr.takeError();
+
+  Binary &Binary = *BinOrErr->get();
   // Universal MachO is not a subclass of ObjectFile, so it needs to be handled
   // here with the other binary types.
   if (Binary.isMachO() || Binary.isMachOUniversalBinary())
     return macho2yaml(outs(), Binary);
-  // TODO: If this is an archive, then burst it and dump each entry
   if (ObjectFile *Obj = dyn_cast<ObjectFile>(&Binary))
     return dumpObject(*Obj);
   if (MinidumpFile *Minidump = dyn_cast<MinidumpFile>(&Binary))
diff --git a/tools/obj2yaml/obj2yaml.h b/tools/obj2yaml/obj2yaml.h
index c41010f111b..e3120502710 100644
--- a/tools/obj2yaml/obj2yaml.h
+++ b/tools/obj2yaml/obj2yaml.h
@@ -17,6 +17,7 @@
 #include "llvm/Object/Wasm.h"
 #include "llvm/Object/XCOFFObjectFile.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/MemoryBufferRef.h"
 #include <system_error>
 
 std::error_code coff2yaml(llvm::raw_ostream &Out,
@@ -31,6 +32,7 @@ std::error_code xcoff2yaml(llvm::raw_ostream &Out,
                            const llvm::object::XCOFFObjectFile &Obj);
 std::error_code wasm2yaml(llvm::raw_ostream &Out,
                           const llvm::object::WasmObjectFile &Obj);
+llvm::Error archive2yaml(llvm::raw_ostream &Out, llvm::MemoryBufferRef Source);
 
 // Forward decls for dwarf2yaml
 namespace llvm {