1 files changed, 566 insertions, 0 deletions
diff --git a/js/src/devtools/rootAnalysis/t/hazards/source.cpp b/js/src/devtools/rootAnalysis/t/hazards/source.cpp
new file mode 100644
index 0000000000..fe991653af
--- /dev/null
+++ b/js/src/devtools/rootAnalysis/t/hazards/source.cpp
@@ -0,0 +1,566 @@
+/* -*- 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 <utility>
+
+#define ANNOTATE(property) __attribute__((annotate(property)))
+
+// MarkVariableAsGCSafe is a magic function name used as an
+// explicit annotation.
+
+namespace JS {
+namespace detail {
+template <typename T>
+static void MarkVariableAsGCSafe(T&) {
+  asm("");
+}
+}  // namespace detail
+}  // namespace JS
+
+#define JS_HAZ_VARIABLE_IS_GC_SAFE(var) JS::detail::MarkVariableAsGCSafe(var)
+
+struct Cell {
+  int f;
+} ANNOTATE("GC Thing");
+
+template <typename T, typename U>
+struct UntypedContainer {
+  char data[sizeof(T) + sizeof(U)];
+} ANNOTATE("moz_inherit_type_annotations_from_template_args");
+
+struct RootedCell {
+  RootedCell(Cell*) {}
+} ANNOTATE("Rooted Pointer");
+
+class AutoSuppressGC_Base {
+ public:
+  AutoSuppressGC_Base() {}
+  ~AutoSuppressGC_Base() {}
+} ANNOTATE("Suppress GC");
+
+class AutoSuppressGC_Child : public AutoSuppressGC_Base {
+ public:
+  AutoSuppressGC_Child() : AutoSuppressGC_Base() {}
+};
+
+class AutoSuppressGC {
+  AutoSuppressGC_Child helpImBeingSuppressed;
+
+ public:
+  AutoSuppressGC() {}
+};
+
+class AutoCheckCannotGC {
+ public:
+  AutoCheckCannotGC() {}
+  ~AutoCheckCannotGC() { asm(""); }
+} ANNOTATE("Invalidated by GC");
+
+extern void GC() ANNOTATE("GC Call");
+extern void invisible();
+
+void GC() {
+  // If the implementation is too trivial, the function body won't be emitted at
+  // all.
+  asm("");
+  invisible();
+}
+
+extern void usecell(Cell*);
+
+extern bool flipcoin();
+
+void suppressedFunction() {
+  GC();  // Calls GC, but is always called within AutoSuppressGC
+}
+
+void halfSuppressedFunction() {
+  GC();  // Calls GC, but is sometimes called within AutoSuppressGC
+}
+
+void unsuppressedFunction() {
+  GC();  // Calls GC, never within AutoSuppressGC
+}
+
+class IDL_Interface {
+ public:
+  ANNOTATE("Can run script") virtual void canScriptThis() {}
+  virtual void cannotScriptThis() {}
+  ANNOTATE("Can run script") virtual void overridden_canScriptThis() = 0;
+  virtual void overridden_cannotScriptThis() = 0;
+};
+
+class IDL_Subclass : public IDL_Interface {
+  ANNOTATE("Can run script") void overridden_canScriptThis() override {}
+  void overridden_cannotScriptThis() override {}
+};
+
+volatile static int x = 3;
+volatile static int* xp = &x;
+struct GCInDestructor {
+  ~GCInDestructor() {
+    invisible();
+    asm("");
+    *xp = 4;
+    GC();
+  }
+};
+
+template <typename T>
+void usecontainer(T* value) {
+  if (value) asm("");
+}
+
+Cell* cell() {
+  static Cell c;
+  return &c;
+}
+
+Cell* f() {
+  GCInDestructor kaboom;
+
+  Cell* cell1 = cell();
+  Cell* cell2 = cell();
+  Cell* cell3 = cell();
+  Cell* cell4 = cell();
+  {
+    AutoSuppressGC nogc;
+    suppressedFunction();
+    halfSuppressedFunction();
+  }
+  usecell(cell1);
+  halfSuppressedFunction();
+  usecell(cell2);
+  unsuppressedFunction();
+  {
+    // Old bug: it would look from the first AutoSuppressGC constructor it
+    // found to the last destructor. This statement *should* have no effect.
+    AutoSuppressGC nogc;
+  }
+  usecell(cell3);
+  Cell* cell5 = cell();
+  usecell(cell5);
+
+  {
+    // Templatized container that inherits attributes from Cell*, should
+    // report a hazard.
+    UntypedContainer<int, Cell*> container1;
+    usecontainer(&container1);
+    GC();
+    usecontainer(&container1);
+  }
+
+  {
+    // As above, but with a non-GC type.
+    UntypedContainer<int, double> container2;
+    usecontainer(&container2);
+    GC();
+    usecontainer(&container2);
+  }
+
+  // Hazard in return value due to ~GCInDestructor
+  Cell* cell6 = cell();
+  return cell6;
+}
+
+Cell* copy_and_gc(Cell* src) {
+  GC();
+  return reinterpret_cast<Cell*>(88);
+}
+
+void use(Cell* cell) {
+  static int x = 0;
+  if (cell) x++;
+}
+
+struct CellContainer {
+  Cell* cell;
+  CellContainer() { asm(""); }
+};
+
+void loopy() {
+  Cell cell;
+
+  // No hazard: haz1 is not live during call to copy_and_gc.
+  Cell* haz1;
+  for (int i = 0; i < 10; i++) {
+    haz1 = copy_and_gc(haz1);
+  }
+
+  // No hazard: haz2 is live up to just before the GC, and starting at the
+  // next statement after it, but not across the GC.
+  Cell* haz2 = &cell;
+  for (int j = 0; j < 10; j++) {
+    use(haz2);
+    GC();
+    haz2 = &cell;
+  }
+
+  // Hazard: haz3 is live from the final statement in one iteration, across
+  // the GC in the next, to the use in the 2nd statement.
+  Cell* haz3;
+  for (int k = 0; k < 10; k++) {
+    GC();
+    use(haz3);
+    haz3 = &cell;
+  }
+
+  // Hazard: haz4 is live across a GC hidden in a loop.
+  Cell* haz4 = &cell;
+  for (int i2 = 0; i2 < 10; i2++) {
+    GC();
+  }
+  use(haz4);
+
+  // Hazard: haz5 is live from within a loop across a GC.
+  Cell* haz5;
+  for (int i3 = 0; i3 < 10; i3++) {
+    haz5 = &cell;
+  }
+  GC();
+  use(haz5);
+
+  // No hazard: similar to the haz3 case, but verifying that we do not get
+  // into an infinite loop.
+  Cell* haz6;
+  for (int i4 = 0; i4 < 10; i4++) {
+    GC();
+    haz6 = &cell;
+  }
+
+  // No hazard: haz7 is constructed within the body, so it can't make a
+  // hazard across iterations. Note that this requires CellContainer to have
+  // a constructor, because otherwise the analysis doesn't see where
+  // variables are declared. (With the constructor, it knows that
+  // construction of haz7 obliterates any previous value it might have had.
+  // Not that that's possible given its scope, but the analysis doesn't get
+  // that information.)
+  for (int i5 = 0; i5 < 10; i5++) {
+    GC();
+    CellContainer haz7;
+    use(haz7.cell);
+    haz7.cell = &cell;
+  }
+
+  // Hazard: make sure we *can* see hazards across iterations involving
+  // CellContainer;
+  CellContainer haz8;
+  for (int i6 = 0; i6 < 10; i6++) {
+    GC();
+    use(haz8.cell);
+    haz8.cell = &cell;
+  }
+}
+
+namespace mozilla {
+template <typename T>
+class UniquePtr {
+  T* val;
+
+ public:
+  UniquePtr() : val(nullptr) { asm(""); }
+  UniquePtr(T* p) : val(p) {}
+  UniquePtr(UniquePtr<T>&& u) : val(u.val) { u.val = nullptr; }
+  ~UniquePtr() { use(val); }
+  T* get() { return val; }
+  void reset() { val = nullptr; }
+} ANNOTATE("moz_inherit_type_annotations_from_template_args");
+}  // namespace mozilla
+
+extern void consume(mozilla::UniquePtr<Cell> uptr);
+
+void safevals() {
+  Cell cell;
+
+  // Simple hazard.
+  Cell* unsafe1 = &cell;
+  GC();
+  use(unsafe1);
+
+  // Safe because it's known to be nullptr.
+  Cell* safe2 = &cell;
+  safe2 = nullptr;
+  GC();
+  use(safe2);
+
+  // Unsafe because it may not be nullptr.
+  Cell* unsafe3 = &cell;
+  if (reinterpret_cast<long>(&cell) & 0x100) {
+    unsafe3 = nullptr;
+  }
+  GC();
+  use(unsafe3);
+
+  // Unsafe because it's not nullptr anymore.
+  Cell* unsafe3b = &cell;
+  unsafe3b = nullptr;
+  unsafe3b = &cell;
+  GC();
+  use(unsafe3b);
+
+  // Hazard involving UniquePtr.
+  {
+    mozilla::UniquePtr<Cell> unsafe4(&cell);
+    GC();
+    // Destructor uses unsafe4.
+  }
+
+  // reset() to safe value before the GC.
+  {
+    mozilla::UniquePtr<Cell> safe5(&cell);
+    safe5.reset();
+    GC();
+  }
+
+  // reset() to safe value after the GC.
+  {
+    mozilla::UniquePtr<Cell> safe6(&cell);
+    GC();
+    safe6.reset();
+  }
+
+  // reset() to safe value after the GC -- but we've already used it, so it's
+  // too late.
+  {
+    mozilla::UniquePtr<Cell> unsafe7(&cell);
+    GC();
+    use(unsafe7.get());
+    unsafe7.reset();
+  }
+
+  // initialized to safe value.
+  {
+    mozilla::UniquePtr<Cell> safe8;
+    GC();
+  }
+
+  // passed to a function that takes ownership before GC.
+  {
+    mozilla::UniquePtr<Cell> safe9(&cell);
+    consume(std::move(safe9));
+    GC();
+  }
+
+  // passed to a function that takes ownership after GC.
+  {
+    mozilla::UniquePtr<Cell> unsafe10(&cell);
+    GC();
+    consume(std::move(unsafe10));
+  }
+
+  // annotated to be safe before the GC. (This doesn't make
+  // a lot of sense here; the annotation is for when some
+  // type is known to only contain safe values, eg it is
+  // initialized as empty, or it is a union and we know
+  // that the GC pointer variants are not in use.)
+  {
+    mozilla::UniquePtr<Cell> safe11(&cell);
+    JS_HAZ_VARIABLE_IS_GC_SAFE(safe11);
+    GC();
+  }
+
+  // annotate as safe value after the GC -- since nothing else
+  // has touched the variable, that means it was already safe
+  // during the GC.
+  {
+    mozilla::UniquePtr<Cell> safe12(&cell);
+    GC();
+    JS_HAZ_VARIABLE_IS_GC_SAFE(safe12);
+  }
+
+  // annotate as safe after the GC -- but we've already used it, so it's
+  // too late.
+  {
+    mozilla::UniquePtr<Cell> unsafe13(&cell);
+    GC();
+    use(unsafe13.get());
+    JS_HAZ_VARIABLE_IS_GC_SAFE(unsafe13);
+  }
+
+  // Check JS_HAZ_CAN_RUN_SCRIPT annotation handling.
+  IDL_Subclass sub;
+  IDL_Subclass* subp = &sub;
+  IDL_Interface* base = &sub;
+  {
+    Cell* unsafe14 = &cell;
+    base->canScriptThis();
+    use(unsafe14);
+  }
+  {
+    Cell* unsafe15 = &cell;
+    subp->canScriptThis();
+    use(unsafe15);
+  }
+  {
+    // Almost the same as the last one, except call using the actual object, not
+    // a pointer. The type is known, so there is no danger of the actual type
+    // being a subclass that has overridden the method with an implementation
+    // that calls script.
+    Cell* safe16 = &cell;
+    sub.canScriptThis();
+    use(safe16);
+  }
+  {
+    Cell* safe17 = &cell;
+    base->cannotScriptThis();
+    use(safe17);
+  }
+  {
+    Cell* safe18 = &cell;
+    subp->cannotScriptThis();
+    use(safe18);
+  }
+  {
+    // A use after a GC, but not before. (This does not initialize safe19 by
+    // setting it to a value, because assignment would start its live range, and
+    // this test is to see if a variable with no known live range start requires
+    // a use before the GC or not. It should.)
+    Cell* safe19;
+    GC();
+    extern void initCellPtr(Cell**);
+    initCellPtr(&safe19);
+  }
+}
+
+// Make sure `this` is live at the beginning of a function.
+class Subcell : public Cell {
+  int method() {
+    GC();
+    return f;  // this->f
+  }
+};
+
+template <typename T>
+struct RefPtr {
+  ~RefPtr() { GC(); }
+  bool forget() { return true; }
+  bool use() { return true; }
+  void assign_with_AddRef(T* aRawPtr) { asm(""); }
+};
+
+extern bool flipcoin();
+
+Cell* refptr_test1() {
+  static Cell cell;
+  RefPtr<float> v1;
+  Cell* ref_unsafe1 = &cell;
+  return ref_unsafe1;
+}
+
+Cell* refptr_test2() {
+  static Cell cell;
+  RefPtr<float> v2;
+  Cell* ref_safe2 = &cell;
+  v2.forget();
+  return ref_safe2;
+}
+
+Cell* refptr_test3() {
+  static Cell cell;
+  RefPtr<float> v3;
+  Cell* ref_unsafe3 = &cell;
+  if (x) {
+    v3.forget();
+  }
+  return ref_unsafe3;
+}
+
+Cell* refptr_test4() {
+  static Cell cell;
+  RefPtr<int> r;
+  return &cell;  // hazard in return value
+}
+
+Cell* refptr_test5() {
+  static Cell cell;
+  RefPtr<int> r;
+  return nullptr;  // returning immobile value, so no hazard
+}
+
+float somefloat = 1.2;
+
+Cell* refptr_test6() {
+  static Cell cell;
+  RefPtr<float> v6;
+  Cell* ref_unsafe6 = &cell;
+  // v6 can be used without an intervening forget() before the end of the
+  // function, even though forget() will be called at least once.
+  v6.forget();
+  if (x) {
+    v6.forget();
+    v6.assign_with_AddRef(&somefloat);
+  }
+  return ref_unsafe6;
+}
+
+Cell* refptr_test7() {
+  static Cell cell;
+  RefPtr<float> v7;
+  Cell* ref_unsafe7 = &cell;
+  // Similar to above, but with a loop.
+  while (flipcoin()) {
+    v7.forget();
+    v7.assign_with_AddRef(&somefloat);
+  }
+  return ref_unsafe7;
+}
+
+Cell* refptr_test8() {
+  static Cell cell;
+  RefPtr<float> v8;
+  Cell* ref_unsafe8 = &cell;
+  // If the loop is traversed, forget() will be called. But that doesn't
+  // matter, because even on the last iteration v8.use() will have been called
+  // (and potentially dropped the refcount or whatever.)
+  while (v8.use()) {
+    v8.forget();
+  }
+  return ref_unsafe8;
+}
+
+Cell* refptr_test9() {
+  static Cell cell;
+  RefPtr<float> v9;
+  Cell* ref_safe9 = &cell;
+  // Even when not going through the loop, forget() will be called and so the
+  // dtor will not Release.
+  while (v9.forget()) {
+    v9.assign_with_AddRef(&somefloat);
+  }
+  return ref_safe9;
+}
+
+Cell* refptr_test10() {
+  static Cell cell;
+  RefPtr<float> v10;
+  Cell* ref_unsafe10 = &cell;
+  // The destructor has a backwards path that skips the loop body.
+  v10.assign_with_AddRef(&somefloat);
+  while (flipcoin()) {
+    v10.forget();
+  }
+  return ref_unsafe10;
+}
+
+std::pair<bool, AutoCheckCannotGC> pair_returning_function() {
+  return std::make_pair(true, AutoCheckCannotGC());
+}
+
+void aggr_init_unsafe() {
+  // nogc will be live after the call, so across the GC.
+  auto [ok, nogc] = pair_returning_function();
+  GC();
+}
+
+void aggr_init_safe() {
+  // The analysis should be able to tell that nogc is only live after the call,
+  // not before. (This is to check for a problem where the return value was
+  // getting stored into a different temporary than the local nogc variable,
+  // and so its initialization was never seen and so it was assumed to be live
+  // throughout the function.)
+  GC();
+  auto [ok, nogc] = pair_returning_function();
+}