js/src/vm/UbiNodeShortestPaths.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: set ts=8 sts=2 et sw=2 tw=80:
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "js/UbiNodeShortestPaths.h"
   8
   9 #include "mozilla/Maybe.h"
  10
  11 #include <stdio.h>
  12 #include <utility>
  13
  14 #include "util/Text.h"
  15
  16 namespace JS {
  17 namespace ubi {
  18
  19 JS_PUBLIC_API BackEdge::Ptr BackEdge::clone() const {
  20   auto clone = js::MakeUnique<BackEdge>();
  21   if (!clone) {
  22     return nullptr;
  23   }
  24
  25   clone->predecessor_ = predecessor();
  26   if (name()) {
  27     clone->name_ = js::DuplicateString(name().get());
  28     if (!clone->name_) {
  29       return nullptr;
  30     }
  31   }
  32   return clone;
  33 }
  34
  35 #ifdef DEBUG
  36
  37 static int32_t js_fputs(const char16_t* s, FILE* f) {
  38   while (*s != 0) {
  39     if (fputwc(wchar_t(*s), f) == static_cast<wint_t>(WEOF)) {
  40       return WEOF;
  41     }
  42     s++;
  43   }
  44   return 1;
  45 }
  46
  47 static void dumpNode(const JS::ubi::Node& node) {
  48   fprintf(stderr, "    %p ", (void*)node.identifier());
  49   js_fputs(node.typeName(), stderr);
  50   if (node.coarseType() == JS::ubi::CoarseType::Object) {
  51     if (const char* clsName = node.jsObjectClassName()) {
  52       fprintf(stderr, " [object %s]", clsName);
  53     }
  54   }
  55   fputc('\n', stderr);
  56 }
  57
  58 JS_PUBLIC_API void dumpPaths(JSContext* cx, Node node,
  59                              uint32_t maxNumPaths /* = 10 */) {
  60   JS::ubi::RootList rootList(cx, true);
  61   auto [ok, nogc] = rootList.init();
  62   MOZ_ASSERT(ok);
  63
  64   NodeSet targets;
  65   ok = targets.putNew(node);
  66   MOZ_ASSERT(ok);
  67
  68   auto paths = ShortestPaths::Create(cx, nogc, maxNumPaths, &rootList,
  69                                      std::move(targets));
  70   MOZ_ASSERT(paths.isSome());
  71
  72   int i = 0;
  73   ok = paths->forEachPath(node, [&](Path& path) {
  74     fprintf(stderr, "Path %d:\n", i++);
  75     for (auto backEdge : path) {
  76       dumpNode(backEdge->predecessor());
  77       fprintf(stderr, "            |\n");
  78       fprintf(stderr, "            |\n");
  79       fprintf(stderr, "        '");
  80
  81       const char16_t* name = backEdge->name().get();
  82       if (!name) {
  83         name = u"<no edge name>";
  84       }
  85       js_fputs(name, stderr);
  86       fprintf(stderr, "'\n");
  87
  88       fprintf(stderr, "            |\n");
  89       fprintf(stderr, "            V\n");
  90     }
  91
  92     dumpNode(node);
  93     fputc('\n', stderr);
  94     return true;
  95   });
  96   MOZ_ASSERT(ok);
  97
  98   if (i == 0) {
  99     fprintf(stderr, "No retaining paths found.\n");
 100   }
 101 }
 102 #endif
 103
 104 }  // namespace ubi
 105 }  // namespace JS