diff --git a/llvm/test/tools/llvm-objcopy/Wasm/add-section.test b/llvm/test/tools/llvm-objcopy/Wasm/add-section.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-objcopy/Wasm/add-section.test
@@ -0,0 +1,77 @@
+## This actually tests dumping, removal, and addition.
+# RUN: yaml2obj %s -o %t
+# RUN: llvm-objcopy --dump-section=producers=%t.sec %t
+# RUN: llvm-objcopy -R producers %t %t2
+# RUN: llvm-objcopy --add-section=producers=%t.sec %t2 %t3
+# RUN: obj2yaml %t2 | FileCheck --check-prefix=REMOVED %s
+# RUN: obj2yaml %t3 | FileCheck %s
+
+--- !WASM
+FileHeader:
+  Version:         0x00000001
+Sections:
+  - Type:            TYPE
+    Signatures:
+      - Index:           0
+        ParamTypes:
+          - I32
+        ReturnTypes:
+          - F32
+      - Index:           1
+        ParamTypes:
+          - I32
+          - I64
+        ReturnTypes:     []
+  - Type:            FUNCTION
+    FunctionTypes:
+      - 0
+      - 1
+  - Type:            CODE
+    Relocations:
+      - Type:            R_WASM_TABLE_INDEX_SLEB
+        Index:           0
+        Offset:          0x00000006
+      - Type:            R_WASM_FUNCTION_INDEX_LEB
+        Index:           1
+        Offset:          0x00000025
+    Functions:
+      - Index:              0
+        Locals:
+         - Type:            I32
+           Count:           3
+        Body:            418080808000210020002101200111808080800000210220020F0B
+      - Index:              1
+        Locals:
+         - Type:            I32
+           Count:           1
+        Body:            108180808000210020000F0B
+  - Type:            CUSTOM
+    Name:            linking
+    Version:         2
+    SymbolTable:
+      - Index:           0
+        Kind:            FUNCTION
+        Name:            func1
+        Flags:           [  ]
+        Function:        0
+      - Index:           1
+        Kind:            FUNCTION
+        Name:            func2
+        Flags:           [  ]
+        Function:        1
+  - Type:            CUSTOM
+    Name:            producers
+    Tools:
+      - Name:            clang
+        Version:         9.0.0
+
+...
+
+## Check that the producers section has been removed.
+# REMOVED-NOT: producers
+
+## Check that the producers section has been added back unchanged.
+# CHECK:    Name:            producers
+# CHECK-NEXT:    Tools:
+# CHECK-NEXT:      - Name:            clang
+# CHECK-NEXT:        Version:         9.0.0
diff --git a/llvm/tools/llvm-objcopy/wasm/WasmObjcopy.cpp b/llvm/tools/llvm-objcopy/wasm/WasmObjcopy.cpp
--- a/llvm/tools/llvm-objcopy/wasm/WasmObjcopy.cpp
+++ b/llvm/tools/llvm-objcopy/wasm/WasmObjcopy.cpp
@@ -20,8 +20,66 @@
 using namespace object;
 using namespace wasm;
 
+// Adds named custom section with given contents to the object.
+static void addSection(Object &Obj, StringRef Name,
+                       ArrayRef<uint8_t> Contents) {
+  Section Sec;
+  Sec.SectionType = llvm::wasm::WASM_SEC_CUSTOM;
+  Sec.Name = Name;
+  Sec.setOwnedContents(Contents);
+  Obj.addSections(Sec);
+}
+
+static Error dumpSectionToFile(StringRef SecName, StringRef Filename,
+                               Object &Obj) {
+  for (auto &Sec : Obj.getSections()) {
+    if (Sec.Name == SecName) {
+      ArrayRef<uint8_t> Contents = Sec.getContents();
+      Expected<std::unique_ptr<FileOutputBuffer>> BufferOrErr =
+          FileOutputBuffer::create(Filename, Contents.size());
+      if (!BufferOrErr)
+        return BufferOrErr.takeError();
+      std::unique_ptr<FileOutputBuffer> Buf = std::move(*BufferOrErr);
+      std::copy(Contents.begin(), Contents.end(), Buf->getBufferStart());
+      if (Error E = Buf->commit())
+        return E;
+      return Error::success();
+    }
+  }
+  return createStringError(errc::invalid_argument, "section '%s' not found",
+                           SecName.str().c_str());
+}
 
 static Error handleArgs(const CopyConfig &Config, Object &Obj) {
+  // Only support AddSection, DumpSection, RemoveSection.
+  // Don't support OnlySection yet because we only operate on custom sections.
+  Obj.removeSections([&Config](const Section &Sec) {
+    if (Config.ToRemove.matches(Sec.Name))
+      return true;
+    return false;
+  });
+
+  for (const auto &Flag : Config.AddSection) {
+    StringRef SecName, FileName;
+    std::tie(SecName, FileName) = Flag.split("=");
+    auto BufOrErr = MemoryBuffer::getFile(FileName);
+    if (!BufOrErr)
+      return createFileError(FileName, errorCodeToError(BufOrErr.getError()));
+    auto Buf = std::move(*BufOrErr);
+    addSection(
+        Obj, SecName,
+        makeArrayRef(reinterpret_cast<const uint8_t *>(Buf->getBufferStart()),
+                     Buf->getBufferSize()));
+  }
+
+  for (const auto &Flag : Config.DumpSection) {
+    StringRef SecName;
+    StringRef FileName;
+    std::tie(SecName, FileName) = Flag.split("=");
+    if (Error E = dumpSectionToFile(SecName, FileName, Obj))
+      return E;
+  }
+
   if (!Config.AddGnuDebugLink.empty() || !Config.BuildIdLinkDir.empty() ||
       Config.BuildIdLinkInput || Config.BuildIdLinkOutput ||
       Config.ExtractPartition || !Config.SplitDWO.empty() ||
@@ -34,11 +92,10 @@
       !Config.UnneededSymbolsToRemove.empty() ||
       !Config.SymbolsToWeaken.empty() || !Config.SymbolsToKeepGlobal.empty() ||
       !Config.SectionsToRename.empty() || !Config.SetSectionAlignment.empty() ||
-      !Config.SetSectionFlags.empty() || !Config.SymbolsToRename.empty() ||
-      !Config.ToRemove.empty() || !Config.DumpSection.empty() || !Config.AddSection.empty()) {
+      !Config.SetSectionFlags.empty() || !Config.SymbolsToRename.empty()) {
     return createStringError(
         llvm::errc::invalid_argument,
-        "No flags are supported yet other than basic copying");
+        "Only add-section, dump-section, and remove-section are supported");
   }
   return Error::success();
 }