1 files changed, 105 insertions, 0 deletions
diff --git a/js/src/vm/UbiNodeShortestPaths.cpp b/js/src/vm/UbiNodeShortestPaths.cpp
new file mode 100644
index 0000000000..f11cf19035
--- /dev/null
+++ b/js/src/vm/UbiNodeShortestPaths.cpp
@@ -0,0 +1,105 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * 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/. */
+
+#include "js/UbiNodeShortestPaths.h"
+
+#include "mozilla/Maybe.h"
+
+#include <stdio.h>
+#include <utility>
+
+#include "util/Text.h"
+
+namespace JS {
+namespace ubi {
+
+JS_PUBLIC_API BackEdge::Ptr BackEdge::clone() const {
+  auto clone = js::MakeUnique<BackEdge>();
+  if (!clone) {
+    return nullptr;
+  }
+
+  clone->predecessor_ = predecessor();
+  if (name()) {
+    clone->name_ = js::DuplicateString(name().get());
+    if (!clone->name_) {
+      return nullptr;
+    }
+  }
+  return clone;
+}
+
+#ifdef DEBUG
+
+static int32_t js_fputs(const char16_t* s, FILE* f) {
+  while (*s != 0) {
+    if (fputwc(wchar_t(*s), f) == static_cast<wint_t>(WEOF)) {
+      return WEOF;
+    }
+    s++;
+  }
+  return 1;
+}
+
+static void dumpNode(const JS::ubi::Node& node) {
+  fprintf(stderr, "    %p ", (void*)node.identifier());
+  js_fputs(node.typeName(), stderr);
+  if (node.coarseType() == JS::ubi::CoarseType::Object) {
+    if (const char* clsName = node.jsObjectClassName()) {
+      fprintf(stderr, " [object %s]", clsName);
+    }
+  }
+  fputc('\n', stderr);
+}
+
+JS_PUBLIC_API void dumpPaths(JSContext* cx, Node node,
+                             uint32_t maxNumPaths /* = 10 */) {
+  JS::ubi::RootList rootList(cx, true);
+  auto [ok, nogc] = rootList.init();
+  MOZ_ASSERT(ok);
+
+  NodeSet targets;
+  ok = targets.putNew(node);
+  MOZ_ASSERT(ok);
+
+  auto paths = ShortestPaths::Create(cx, nogc, maxNumPaths, &rootList,
+                                     std::move(targets));
+  MOZ_ASSERT(paths.isSome());
+
+  int i = 0;
+  ok = paths->forEachPath(node, [&](Path& path) {
+    fprintf(stderr, "Path %d:\n", i++);
+    for (auto backEdge : path) {
+      dumpNode(backEdge->predecessor());
+      fprintf(stderr, "            |\n");
+      fprintf(stderr, "            |\n");
+      fprintf(stderr, "        '");
+
+      const char16_t* name = backEdge->name().get();
+      if (!name) {
+        name = u"<no edge name>";
+      }
+      js_fputs(name, stderr);
+      fprintf(stderr, "'\n");
+
+      fprintf(stderr, "            |\n");
+      fprintf(stderr, "            V\n");
+    }
+
+    dumpNode(node);
+    fputc('\n', stderr);
+    return true;
+  });
+  MOZ_ASSERT(ok);
+
+  if (i == 0) {
+    fprintf(stderr, "No retaining paths found.\n");
+  }
+}
+#endif
+
+}  // namespace ubi
+}  // namespace JS