1 files changed, 118 insertions, 0 deletions
diff --git a/src/tools/wasm-link-metadata.cpp b/src/tools/wasm-link-metadata.cpp
new file mode 100644
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+++ b/src/tools/wasm-link-metadata.cpp
@@ -0,0 +1,118 @@
+/*
+ * Copyright 2017 WebAssembly Community Group participants
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//
+// wasm-link-metadata console tool
+// Reads wasm .o file and emits .json metadata
+//
+
+#include <exception>
+
+#include "abi/wasm-object.h"
+#include "ir/trapping.h"
+#include "support/colors.h"
+#include "support/command-line.h"
+#include "support/file.h"
+#include "wasm-binary.h"
+#include "wasm-emscripten.h"
+#include "wasm-io.h"
+#include "wasm-linker.h"
+#include "wasm-printing.h"
+#include "wasm-validator.h"
+
+using namespace cashew;
+using namespace wasm;
+
+void parseLinkingSection(std::vector<char> const& data, uint32_t &dataSize) {
+  unsigned idx = 0;
+  auto get = [&idx, &data](){ return data[idx++]; };
+  auto readNext = [get](){
+    U32LEB leb;
+    leb.read(get);
+    return leb.value;
+  };
+
+  while (idx < data.size()) {
+    ABI::LinkType type = static_cast<ABI::LinkType>(readNext());
+    uint32_t size = readNext();
+    uint32_t startIdx = idx;
+
+    switch(type) {
+    case ABI::WASM_DATA_SIZE: {
+      dataSize = readNext();
+      break;
+    }
+    default: {
+      break;
+    }
+    }
+    // Always go to the end of the subsection based on size, not contents.
+    idx = startIdx + size;
+  }
+}
+
+int main(int argc, const char *argv[]) {
+  std::string infile;
+  std::string outfile;
+  Options options("wasm-link-metadata",
+                  "Reads wasm .o file and emits .json metadata");
+  options
+      .add("--output", "-o", "Output file",
+           Options::Arguments::One,
+           [&outfile](Options *o, const std::string &argument) {
+             outfile = argument;
+             Colors::disable();
+           })
+      .add_positional("INFILE", Options::Arguments::One,
+                      [&infile](Options *o, const std::string &argument) {
+                        infile = argument;
+                      });
+  options.parse(argc, argv);
+
+  if (infile == "") {
+    Fatal() << "Need to specify an infile\n";
+  }
+
+  Module wasm;
+  try {
+    ModuleReader reader;
+    reader.readBinary(infile, wasm);
+  } catch (ParseException& p) {
+    p.dump(std::cerr);
+    Fatal() << "error in parsing wasm binary";
+  }
+
+  if (options.debug) {
+    WasmPrinter::printModule(&wasm, std::cerr);
+  }
+
+  uint32_t dataSize = 0;
+  for (auto &section : wasm.userSections) {
+    if (section.name == "linking") {
+      parseLinkingSection(section.data, dataSize);
+    }
+  }
+
+  std::vector<Name> initializerFunctions;
+  initializerFunctions.push_back("__wasm_call_ctors");
+
+  EmscriptenGlueGenerator generator(wasm);
+  std::string metadata = generator.generateEmscriptenMetadata(dataSize, initializerFunctions);
+  Output output(outfile, Flags::Text, Flags::Release);
+  output << metadata;
+
+  return 0;
+}