1 files changed, 66 insertions, 0 deletions
diff --git a/devtools/client/shared/source-map-loader/wasm-dwarf/convertToJSON.js b/devtools/client/shared/source-map-loader/wasm-dwarf/convertToJSON.js
new file mode 100644
index 0000000000..9faae5c901
--- /dev/null
+++ b/devtools/client/shared/source-map-loader/wasm-dwarf/convertToJSON.js
@@ -0,0 +1,66 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+/* eslint camelcase: 0*/
+
+"use strict";
+
+const {
+  getDwarfToWasmData,
+} = require("resource://devtools/client/shared/source-map-loader/wasm-dwarf/wasmAsset.js");
+
+let cachedWasmModule;
+let utf8Decoder;
+
+function convertDwarf(wasm, instance) {
+  const { memory, alloc_mem, free_mem, convert_dwarf } = instance.exports;
+  const wasmPtr = alloc_mem(wasm.byteLength);
+  new Uint8Array(memory.buffer, wasmPtr, wasm.byteLength).set(
+    new Uint8Array(wasm)
+  );
+  const resultPtr = alloc_mem(12);
+  const enableXScopes = true;
+  const success = convert_dwarf(
+    wasmPtr,
+    wasm.byteLength,
+    resultPtr,
+    resultPtr + 4,
+    enableXScopes
+  );
+  free_mem(wasmPtr);
+  const resultView = new DataView(memory.buffer, resultPtr, 12);
+  const outputPtr = resultView.getUint32(0, true),
+    outputLen = resultView.getUint32(4, true);
+  free_mem(resultPtr);
+  if (!success) {
+    throw new Error("Unable to convert from DWARF sections");
+  }
+  if (!utf8Decoder) {
+    utf8Decoder = new TextDecoder("utf-8");
+  }
+  const output = utf8Decoder.decode(
+    new Uint8Array(memory.buffer, outputPtr, outputLen)
+  );
+  free_mem(outputPtr);
+  return output;
+}
+
+async function convertToJSON(buffer) {
+  // Note: We don't 'await' here because it could mean that multiple
+  // calls to 'convertToJSON' could cause multiple fetches to be started.
+  cachedWasmModule = cachedWasmModule || loadConverterModule();
+
+  return convertDwarf(buffer, await cachedWasmModule);
+}
+
+async function loadConverterModule() {
+  const wasm = await getDwarfToWasmData();
+  const imports = {};
+  const { instance } = await WebAssembly.instantiate(wasm, imports);
+  return instance;
+}
+
+module.exports = {
+  convertToJSON,
+};