8 files changed, 420 insertions, 0 deletions
diff --git a/llvm/tools/llvm-objcopy/wasm/Object.cpp b/llvm/tools/llvm-objcopy/wasm/Object.cpp
new file mode 100644
index 0000000000000..0c416483663f2
--- /dev/null
+++ b/llvm/tools/llvm-objcopy/wasm/Object.cpp
@@ -0,0 +1,36 @@
+//===- Object.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 "Object.h"
+
+#include "llvm/Support/LEB128.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace llvm {
+namespace objcopy {
+namespace wasm {
+
+using namespace object;
+using namespace llvm::wasm;
+
+void Object::addSectionWithOwnedContents(
+    Section NewSection, std::unique_ptr<MemoryBuffer> &&Content) {
+  Sections.push_back(NewSection);
+  OwnedContents.emplace_back(std::move(Content));
+}
+
+void Object::removeSections(function_ref<bool(const Section &)> ToRemove) {
+  // TODO: remove reloc sections for the removed section, handle symbols, etc.
+  Sections.erase(
+      std::remove_if(std::begin(Sections), std::end(Sections), ToRemove),
+      std::end(Sections));
+}
+
+} // end namespace wasm
+} // end namespace objcopy
+} // end namespace llvm
diff --git a/llvm/tools/llvm-objcopy/wasm/Object.h b/llvm/tools/llvm-objcopy/wasm/Object.h
new file mode 100644
index 0000000000000..9db91c41e2e26
--- /dev/null
+++ b/llvm/tools/llvm-objcopy/wasm/Object.h
@@ -0,0 +1,47 @@
+//===- Object.h -------------------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_LLVM_OBJCOPY_WASM_OBJECT_H
+#define LLVM_TOOLS_LLVM_OBJCOPY_WASM_OBJECT_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Object/Wasm.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include <vector>
+
+namespace llvm {
+namespace objcopy {
+namespace wasm {
+
+struct Section {
+  // For now, each section is only an opaque binary blob with no distinction
+  // between custom and known sections.
+  uint8_t SectionType;
+  StringRef Name;
+  ArrayRef<uint8_t> Contents;
+};
+
+struct Object {
+  llvm::wasm::WasmObjectHeader Header;
+  // For now don't discriminate between kinds of sections.
+  std::vector<Section> Sections;
+
+  void addSectionWithOwnedContents(Section NewSection,
+                                   std::unique_ptr<MemoryBuffer> &&Content);
+  void removeSections(function_ref<bool(const Section &)> ToRemove);
+
+private:
+  std::vector<std::unique_ptr<MemoryBuffer>> OwnedContents;
+};
+
+} // end namespace wasm
+} // end namespace objcopy
+} // end namespace llvm
+
+#endif // LLVM_TOOLS_LLVM_OBJCOPY_WASM_OBJECT_H
diff --git a/llvm/tools/llvm-objcopy/wasm/Reader.cpp b/llvm/tools/llvm-objcopy/wasm/Reader.cpp
new file mode 100644
index 0000000000000..13fa84ad80201
--- /dev/null
+++ b/llvm/tools/llvm-objcopy/wasm/Reader.cpp
@@ -0,0 +1,33 @@
+//===- Reader.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 "Reader.h"
+
+namespace llvm {
+namespace objcopy {
+namespace wasm {
+
+using namespace object;
+using namespace llvm::wasm;
+
+Expected<std::unique_ptr<Object>> Reader::create() const {
+  auto Obj = std::make_unique<Object>();
+  Obj->Header = WasmObj.getHeader();
+  std::vector<Section> Sections;
+  Obj->Sections.reserve(WasmObj.getNumSections());
+  for (const SectionRef &Sec : WasmObj.sections()) {
+    const WasmSection &WS = WasmObj.getWasmSection(Sec);
+    Obj->Sections.push_back(
+        {static_cast<uint8_t>(WS.Type), WS.Name, WS.Content});
+  }
+  return std::move(Obj);
+}
+
+} // end namespace wasm
+} // end namespace objcopy
+} // end namespace llvm
diff --git a/llvm/tools/llvm-objcopy/wasm/Reader.h b/llvm/tools/llvm-objcopy/wasm/Reader.h
new file mode 100644
index 0000000000000..2dcf7dde029a0
--- /dev/null
+++ b/llvm/tools/llvm-objcopy/wasm/Reader.h
@@ -0,0 +1,31 @@
+//===- Reader.h -------------------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_LLVM_OBJCOPY_WASM_READER_H
+#define LLVM_TOOLS_LLVM_OBJCOPY_WASM_READER_H
+
+#include "Object.h"
+
+namespace llvm {
+namespace objcopy {
+namespace wasm {
+
+class Reader {
+public:
+  explicit Reader(const object::WasmObjectFile &O) : WasmObj(O) {}
+  Expected<std::unique_ptr<Object>> create() const;
+
+private:
+  const object::WasmObjectFile &WasmObj;
+};
+
+} // end namespace wasm
+} // end namespace objcopy
+} // end namespace llvm
+
+#endif // LLVM_TOOLS_LLVM_OBJCOPY_WASM_READER_H
diff --git a/llvm/tools/llvm-objcopy/wasm/WasmObjcopy.cpp b/llvm/tools/llvm-objcopy/wasm/WasmObjcopy.cpp
new file mode 100644
index 0000000000000..20781cef2d33a
--- /dev/null
+++ b/llvm/tools/llvm-objcopy/wasm/WasmObjcopy.cpp
@@ -0,0 +1,114 @@
+//===- WasmObjcopy.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 "WasmObjcopy.h"
+#include "Buffer.h"
+#include "CopyConfig.h"
+#include "Object.h"
+#include "Reader.h"
+#include "Writer.h"
+#include "llvm-objcopy.h"
+#include "llvm/Support/Errc.h"
+
+namespace llvm {
+namespace objcopy {
+namespace wasm {
+
+using namespace object;
+
+static Error dumpSectionToFile(StringRef SecName, StringRef Filename,
+                               Object &Obj) {
+  for (const Section &Sec : Obj.Sections) {
+    if (Sec.Name == SecName) {
+      ArrayRef<uint8_t> Contents = Sec.Contents;
+      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 for now.
+  for (StringRef Flag : Config.DumpSection) {
+    StringRef SecName;
+    StringRef FileName;
+    std::tie(SecName, FileName) = Flag.split("=");
+    if (Error E = dumpSectionToFile(SecName, FileName, Obj))
+      return createFileError(FileName, std::move(E));
+  }
+
+  Obj.removeSections([&Config](const Section &Sec) {
+    if (Config.ToRemove.matches(Sec.Name))
+      return true;
+    return false;
+  });
+
+  for (StringRef Flag : Config.AddSection) {
+    StringRef SecName, FileName;
+    std::tie(SecName, FileName) = Flag.split("=");
+    ErrorOr<std::unique_ptr<MemoryBuffer>> BufOrErr =
+        MemoryBuffer::getFile(FileName);
+    if (!BufOrErr)
+      return createFileError(FileName, errorCodeToError(BufOrErr.getError()));
+    Section Sec;
+    Sec.SectionType = llvm::wasm::WASM_SEC_CUSTOM;
+    Sec.Name = SecName;
+    std::unique_ptr<MemoryBuffer> Buf = std::move(*BufOrErr);
+    Sec.Contents = makeArrayRef<uint8_t>(
+        reinterpret_cast<const uint8_t *>(Buf->getBufferStart()),
+        Buf->getBufferSize());
+    Obj.addSectionWithOwnedContents(Sec, std::move(Buf));
+  }
+
+  if (!Config.AddGnuDebugLink.empty() || !Config.BuildIdLinkDir.empty() ||
+      Config.BuildIdLinkInput || Config.BuildIdLinkOutput ||
+      Config.ExtractPartition || !Config.SplitDWO.empty() ||
+      !Config.SymbolsPrefix.empty() || !Config.AllocSectionsPrefix.empty() ||
+      Config.DiscardMode != DiscardType::None || Config.NewSymbolVisibility ||
+      !Config.SymbolsToAdd.empty() || !Config.RPathToAdd.empty() ||
+      !Config.OnlySection.empty() || !Config.SymbolsToGlobalize.empty() ||
+      !Config.SymbolsToKeep.empty() || !Config.SymbolsToLocalize.empty() ||
+      !Config.SymbolsToRemove.empty() ||
+      !Config.UnneededSymbolsToRemove.empty() ||
+      !Config.SymbolsToWeaken.empty() || !Config.SymbolsToKeepGlobal.empty() ||
+      !Config.SectionsToRename.empty() || !Config.SetSectionAlignment.empty() ||
+      !Config.SetSectionFlags.empty() || !Config.SymbolsToRename.empty()) {
+    return createStringError(
+        llvm::errc::invalid_argument,
+        "only add-section, dump-section, and remove-section are supported");
+  }
+  return Error::success();
+}
+
+Error executeObjcopyOnBinary(const CopyConfig &Config,
+                             object::WasmObjectFile &In, Buffer &Out) {
+  Reader TheReader(In);
+  Expected<std::unique_ptr<Object>> ObjOrErr = TheReader.create();
+  if (!ObjOrErr)
+    return createFileError(Config.InputFilename, ObjOrErr.takeError());
+  Object *Obj = ObjOrErr->get();
+  assert(Obj && "Unable to deserialize Wasm object");
+  if (Error E = handleArgs(Config, *Obj))
+    return E;
+  Writer TheWriter(*Obj, Out);
+  if (Error E = TheWriter.write())
+    return createFileError(Config.OutputFilename, std::move(E));
+  return Error::success();
+}
+
+} // end namespace wasm
+} // end namespace objcopy
+} // end namespace llvm
diff --git a/llvm/tools/llvm-objcopy/wasm/WasmObjcopy.h b/llvm/tools/llvm-objcopy/wasm/WasmObjcopy.h
new file mode 100644
index 0000000000000..3557d5c0a50df
--- /dev/null
+++ b/llvm/tools/llvm-objcopy/wasm/WasmObjcopy.h
@@ -0,0 +1,31 @@
+//===- WasmObjcopy.h -------------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_LLVM_OBJCOPY_WASM_WASMOBJCOPY_H
+#define LLVM_TOOLS_LLVM_OBJCOPY_WASM_WASMOBJCOPY_H
+
+namespace llvm {
+class Error;
+
+namespace object {
+class WasmObjectFile;
+} // end namespace object
+
+namespace objcopy {
+struct CopyConfig;
+class Buffer;
+
+namespace wasm {
+Error executeObjcopyOnBinary(const CopyConfig &Config,
+                             object::WasmObjectFile &In, Buffer &Out);
+
+} // end namespace wasm
+} // end namespace objcopy
+} // end namespace llvm
+
+#endif // LLVM_TOOLS_LLVM_OBJCOPY_WASM_WASMOBJCOPY_H
diff --git a/llvm/tools/llvm-objcopy/wasm/Writer.cpp b/llvm/tools/llvm-objcopy/wasm/Writer.cpp
new file mode 100644
index 0000000000000..50d26507b4983
--- /dev/null
+++ b/llvm/tools/llvm-objcopy/wasm/Writer.cpp
@@ -0,0 +1,78 @@
+//===- Writer.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 "Writer.h"
+#include "llvm/BinaryFormat/Wasm.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/LEB128.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace llvm {
+namespace objcopy {
+namespace wasm {
+
+using namespace object;
+using namespace llvm::wasm;
+
+Writer::SectionHeader Writer::createSectionHeader(const Section &S,
+                                                  size_t &SectionSize) {
+  SectionHeader Header;
+  raw_svector_ostream OS(Header);
+  OS << S.SectionType;
+  bool HasName = S.SectionType == WASM_SEC_CUSTOM;
+  SectionSize = S.Contents.size();
+  if (HasName)
+    SectionSize += getULEB128Size(S.Name.size()) + S.Name.size();
+  // Pad the LEB value out to 5 bytes to make it a predictable size, and
+  // match the behavior of clang.
+  encodeULEB128(SectionSize, OS, 5);
+  if (HasName) {
+    encodeULEB128(S.Name.size(), OS);
+    OS << S.Name;
+  }
+  // Total section size is the content size plus 1 for the section type and
+  // 5 for the LEB-encoded size.
+  SectionSize = SectionSize + 1 + 5;
+  return Header;
+}
+
+size_t Writer::finalize() {
+  size_t ObjectSize = sizeof(WasmMagic) + sizeof(WasmVersion);
+  SectionHeaders.reserve(Obj.Sections.size());
+  // Finalize the headers of each section so we know the total size.
+  for (const Section &S : Obj.Sections) {
+    size_t SectionSize;
+    SectionHeaders.push_back(createSectionHeader(S, SectionSize));
+    ObjectSize += SectionSize;
+  }
+  return ObjectSize;
+}
+
+Error Writer::write() {
+  size_t FileSize = finalize();
+  if (Error E = Buf.allocate(FileSize))
+    return E;
+
+  // Write the header.
+  uint8_t *Ptr = Buf.getBufferStart();
+  Ptr = std::copy(Obj.Header.Magic.begin(), Obj.Header.Magic.end(), Ptr);
+  support::endian::write32le(Ptr, Obj.Header.Version);
+  Ptr += sizeof(Obj.Header.Version);
+
+  // Write each section.
+  for (size_t I = 0, S = SectionHeaders.size(); I < S; ++I) {
+    Ptr = std::copy(SectionHeaders[I].begin(), SectionHeaders[I].end(), Ptr);
+    ArrayRef<uint8_t> Contents = Obj.Sections[I].Contents;
+    Ptr = std::copy(Contents.begin(), Contents.end(), Ptr);
+  }
+  return Buf.commit();
+}
+
+} // end namespace wasm
+} // end namespace objcopy
+} // end namespace llvm
diff --git a/llvm/tools/llvm-objcopy/wasm/Writer.h b/llvm/tools/llvm-objcopy/wasm/Writer.h
new file mode 100644
index 0000000000000..da48ee730c3ba
--- /dev/null
+++ b/llvm/tools/llvm-objcopy/wasm/Writer.h
@@ -0,0 +1,50 @@
+//===- Writer.h -------------------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_LLVM_OBJCOPY_WASM_WRITER_H
+#define LLVM_TOOLS_LLVM_OBJCOPY_WASM_WRITER_H
+
+#include "Buffer.h"
+#include "Object.h"
+#include <cstdint>
+#include <vector>
+
+namespace llvm {
+namespace objcopy {
+namespace wasm {
+
+class Writer {
+public:
+  Writer(Object &Obj, Buffer &Buf) : Obj(Obj), Buf(Buf) {}
+  Error write();
+
+private:
+  using SectionHeader = SmallVector<char, 8>;
+  Object &Obj;
+  Buffer &Buf;
+  std::vector<SectionHeader> SectionHeaders;
+
+  /// Generate a wasm section section header for S.
+  /// The header consists of
+  /// * A one-byte section ID (aka the section type).
+  /// * The size of the section contents, encoded as ULEB128.
+  /// * If the section is a custom section (type 0) it also has a name, which is
+  ///   encoded as a length-prefixed string. The encoded section size *includes*
+  ///   this string.
+  /// See https://webassembly.github.io/spec/core/binary/modules.html#sections
+  /// Return the header and store the total size in SectionSize.
+  static SectionHeader createSectionHeader(const Section &S,
+                                           size_t &SectionSize);
+  size_t finalize();
+};
+
+} // end namespace wasm
+} // end namespace objcopy
+} // end namespace llvm
+
+#endif // LLVM_TOOLS_LLVM_OBJCOPY_WASM_WRITER_H