1 files changed, 160 insertions, 0 deletions
diff --git a/llvm/lib/ObjCopy/wasm/WasmObjcopy.cpp b/llvm/lib/ObjCopy/wasm/WasmObjcopy.cpp
new file mode 100644
index 000000000000..6877cd68bee4
--- /dev/null
+++ b/llvm/lib/ObjCopy/wasm/WasmObjcopy.cpp
@@ -0,0 +1,160 @@
+//===- 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 "llvm/ObjCopy/wasm/WasmObjcopy.h"
+#include "WasmObject.h"
+#include "WasmReader.h"
+#include "WasmWriter.h"
+#include "llvm/ObjCopy/CommonConfig.h"
+#include "llvm/Support/Errc.h"
+#include "llvm/Support/FileOutputBuffer.h"
+
+namespace llvm {
+namespace objcopy {
+namespace wasm {
+
+using namespace object;
+using SectionPred = std::function<bool(const Section &Sec)>;
+
+static bool isDebugSection(const Section &Sec) {
+  return Sec.Name.startswith(".debug");
+}
+
+static bool isLinkerSection(const Section &Sec) {
+  return Sec.Name.startswith("reloc.") || Sec.Name == "linking";
+}
+
+static bool isNameSection(const Section &Sec) { return Sec.Name == "name"; }
+
+// Sections which are known to be "comments" or informational and do not affect
+// program semantics.
+static bool isCommentSection(const Section &Sec) {
+  return Sec.Name == "producers";
+}
+
+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 void removeSections(const CommonConfig &Config, Object &Obj) {
+  SectionPred RemovePred = [](const Section &) { return false; };
+
+  // Explicitly-requested sections.
+  if (!Config.ToRemove.empty()) {
+    RemovePred = [&Config](const Section &Sec) {
+      return Config.ToRemove.matches(Sec.Name);
+    };
+  }
+
+  if (Config.StripDebug) {
+    RemovePred = [RemovePred](const Section &Sec) {
+      return RemovePred(Sec) || isDebugSection(Sec);
+    };
+  }
+
+  if (Config.StripAll) {
+    RemovePred = [RemovePred](const Section &Sec) {
+      return RemovePred(Sec) || isDebugSection(Sec) || isLinkerSection(Sec) ||
+             isNameSection(Sec) || isCommentSection(Sec);
+    };
+  }
+
+  if (Config.OnlyKeepDebug) {
+    RemovePred = [&Config](const Section &Sec) {
+      // Keep debug sections, unless explicitly requested to remove.
+      // Remove everything else, including known sections.
+      return Config.ToRemove.matches(Sec.Name) || !isDebugSection(Sec);
+    };
+  }
+
+  if (!Config.OnlySection.empty()) {
+    RemovePred = [&Config](const Section &Sec) {
+      // Explicitly keep these sections regardless of previous removes.
+      // Remove everything else, inluding known sections.
+      return !Config.OnlySection.matches(Sec.Name);
+    };
+  }
+
+  if (!Config.KeepSection.empty()) {
+    RemovePred = [&Config, RemovePred](const Section &Sec) {
+      // Explicitly keep these sections regardless of previous removes.
+      if (Config.KeepSection.matches(Sec.Name))
+        return false;
+      // Otherwise defer to RemovePred.
+      return RemovePred(Sec);
+    };
+  }
+
+  Obj.removeSections(RemovePred);
+}
+
+static Error handleArgs(const CommonConfig &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));
+  }
+
+  removeSections(Config, Obj);
+
+  for (const NewSectionInfo &NewSection : Config.AddSection) {
+    Section Sec;
+    Sec.SectionType = llvm::wasm::WASM_SEC_CUSTOM;
+    Sec.Name = NewSection.SectionName;
+
+    std::unique_ptr<MemoryBuffer> BufferCopy = MemoryBuffer::getMemBufferCopy(
+        NewSection.SectionData->getBufferStart(),
+        NewSection.SectionData->getBufferIdentifier());
+    Sec.Contents = makeArrayRef<uint8_t>(
+        reinterpret_cast<const uint8_t *>(BufferCopy->getBufferStart()),
+        BufferCopy->getBufferSize());
+
+    Obj.addSectionWithOwnedContents(Sec, std::move(BufferCopy));
+  }
+
+  return Error::success();
+}
+
+Error executeObjcopyOnBinary(const CommonConfig &Config, const WasmConfig &,
+                             object::WasmObjectFile &In, raw_ostream &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