1 files changed, 244 insertions, 0 deletions
diff --git a/js/src/builtin/Array.h b/js/src/builtin/Array.h
new file mode 100644
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+/* -*- 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/. */
+
+/* JS Array interface. */
+
+#ifndef builtin_Array_h
+#define builtin_Array_h
+
+#include "mozilla/Attributes.h"
+#include "mozilla/TextUtils.h"
+
+#include "jspubtd.h"
+
+#include "vm/JSObject.h"
+#include "vm/NativeObject.h"  // js::ShouldUpdateTypes
+
+namespace js {
+
+class ArrayObject;
+
+/* 2^32-2, inclusive */
+const uint32_t MAX_ARRAY_INDEX = 4294967294u;
+
+MOZ_ALWAYS_INLINE bool IdIsIndex(jsid id, uint32_t* indexp) {
+  if (JSID_IS_INT(id)) {
+    int32_t i = JSID_TO_INT(id);
+    MOZ_ASSERT(i >= 0);
+    *indexp = (uint32_t)i;
+    return true;
+  }
+
+  if (MOZ_UNLIKELY(!JSID_IS_STRING(id))) {
+    return false;
+  }
+
+  JSAtom* atom = JSID_TO_ATOM(id);
+  if (atom->length() == 0 ||
+      !mozilla::IsAsciiDigit(atom->latin1OrTwoByteChar(0))) {
+    return false;
+  }
+
+  return js::StringIsArrayIndex(atom, indexp);
+}
+
+// The methods below only create dense boxed arrays.
+
+// Create a dense array with no capacity allocated, length set to 0, in the
+// normal (i.e. non-tenured) heap.
+extern ArrayObject* JS_FASTCALL
+NewDenseEmptyArray(JSContext* cx, HandleObject proto = nullptr);
+
+// Create a dense array with no capacity allocated, length set to 0, in the
+// tenured heap.
+extern ArrayObject* JS_FASTCALL
+NewTenuredDenseEmptyArray(JSContext* cx, HandleObject proto = nullptr);
+
+// Create a dense array with a set length, but without allocating space for the
+// contents. This is useful, e.g., when accepting length from the user.
+extern ArrayObject* JS_FASTCALL NewDenseUnallocatedArray(
+    JSContext* cx, uint32_t length, HandleObject proto = nullptr,
+    NewObjectKind newKind = GenericObject);
+
+// Create a dense array with length and capacity == 'length', initialized length
+// set to 0.
+extern ArrayObject* JS_FASTCALL NewDenseFullyAllocatedArray(
+    JSContext* cx, uint32_t length, HandleObject proto = nullptr,
+    NewObjectKind newKind = GenericObject);
+
+// Create a dense array with length == 'length', initialized length set to 0,
+// and capacity == 'length' clamped to EagerAllocationMaxLength.
+extern ArrayObject* NewDensePartlyAllocatedArray(
+    JSContext* cx, uint32_t length, HandleObject proto = nullptr,
+    NewObjectKind newKind = GenericObject);
+
+// Create a dense array from the given array values, which must be rooted.
+extern ArrayObject* NewDenseCopiedArray(JSContext* cx, uint32_t length,
+                                        const Value* values,
+                                        HandleObject proto = nullptr,
+                                        NewObjectKind newKind = GenericObject);
+
+// Create a dense array based on templateObject with the given length.
+extern ArrayObject* NewDenseFullyAllocatedArrayWithTemplate(
+    JSContext* cx, uint32_t length, ArrayObject* templateObject);
+
+extern ArrayObject* NewArrayWithGroup(JSContext* cx, uint32_t length,
+                                      HandleObjectGroup group);
+
+extern bool ToLength(JSContext* cx, HandleValue v, uint64_t* out);
+
+extern bool GetLengthProperty(JSContext* cx, HandleObject obj,
+                              uint32_t* lengthp);
+
+extern bool SetLengthProperty(JSContext* cx, HandleObject obj, uint32_t length);
+
+/*
+ * Copy 'length' elements from aobj to vp.
+ *
+ * This function assumes 'length' is effectively the result of calling
+ * GetLengthProperty on aobj. vp must point to rooted memory.
+ */
+extern bool GetElements(JSContext* cx, HandleObject aobj, uint32_t length,
+                        js::Value* vp);
+
+/* Natives exposed for optimization by the interpreter and JITs. */
+
+extern bool intrinsic_ArrayNativeSort(JSContext* cx, unsigned argc,
+                                      js::Value* vp);
+
+extern bool array_push(JSContext* cx, unsigned argc, js::Value* vp);
+
+extern bool array_pop(JSContext* cx, unsigned argc, js::Value* vp);
+
+extern bool array_join(JSContext* cx, unsigned argc, js::Value* vp);
+
+extern void ArrayShiftMoveElements(ArrayObject* arr);
+
+extern bool array_shift(JSContext* cx, unsigned argc, js::Value* vp);
+
+extern bool array_slice(JSContext* cx, unsigned argc, js::Value* vp);
+
+extern JSObject* ArraySliceDense(JSContext* cx, HandleObject obj, int32_t begin,
+                                 int32_t end, HandleObject result);
+
+/*
+ * Append the given (non-hole) value to the end of an array.  The array must be
+ * a newborn array -- that is, one which has not been exposed to script for
+ * arbitrary manipulation.  (This method optimizes on the assumption that
+ * extending the array to accommodate the element will never make the array
+ * sparse, which requires that the array be completely filled.)
+ */
+extern bool NewbornArrayPush(JSContext* cx, HandleObject obj, const Value& v);
+
+extern ArrayObject* ArrayConstructorOneArg(JSContext* cx,
+                                           HandleArrayObject templateObject,
+                                           int32_t lengthInt);
+
+#ifdef DEBUG
+extern bool ArrayInfo(JSContext* cx, unsigned argc, Value* vp);
+#endif
+
+/* Array constructor native. Exposed only so the JIT can know its address. */
+extern bool ArrayConstructor(JSContext* cx, unsigned argc, Value* vp);
+
+// Like Array constructor, but doesn't perform GetPrototypeFromConstructor.
+extern bool array_construct(JSContext* cx, unsigned argc, Value* vp);
+
+extern JSString* ArrayToSource(JSContext* cx, HandleObject obj);
+
+extern bool IsCrossRealmArrayConstructor(JSContext* cx, JSObject* obj,
+                                         bool* result);
+
+extern bool ObjectMayHaveExtraIndexedProperties(JSObject* obj);
+
+// JS::IsArray has multiple overloads, use js::IsArrayFromJit to disambiguate.
+extern bool IsArrayFromJit(JSContext* cx, HandleObject obj, bool* isArray);
+
+class MOZ_NON_TEMPORARY_CLASS ArraySpeciesLookup final {
+  /*
+   * An ArraySpeciesLookup holds the following:
+   *
+   *  Array.prototype (arrayProto_)
+   *      To ensure that the incoming array has the standard proto.
+   *
+   *  Array.prototype's shape (arrayProtoShape_)
+   *      To ensure that Array.prototype has not been modified.
+   *
+   *  Array (arrayConstructor_)
+   *  Array's shape (arrayConstructorShape_)
+   *       To ensure that Array has not been modified.
+   *
+   *  Array.prototype's slot number for constructor (arrayProtoConstructorSlot_)
+   *      To quickly retrieve and ensure that the Array constructor
+   *      stored in the slot has not changed.
+   *
+   *  Array's shape for the @@species getter. (arraySpeciesShape_)
+   *  Array's canonical value for @@species (canonicalSpeciesFunc_)
+   *      To quickly retrieve and ensure that the @@species getter for Array
+   *      has not changed.
+   *
+   * MOZ_INIT_OUTSIDE_CTOR fields below are set in |initialize()|.  The
+   * constructor only initializes a |state_| field, that defines whether the
+   * other fields are accessible.
+   */
+
+  // Pointer to canonical Array.prototype and Array.
+  MOZ_INIT_OUTSIDE_CTOR NativeObject* arrayProto_;
+  MOZ_INIT_OUTSIDE_CTOR NativeObject* arrayConstructor_;
+
+  // Shape of matching Array, and slot containing the @@species
+  // property, and the canonical value.
+  MOZ_INIT_OUTSIDE_CTOR Shape* arrayConstructorShape_;
+#ifdef DEBUG
+  MOZ_INIT_OUTSIDE_CTOR Shape* arraySpeciesShape_;
+  MOZ_INIT_OUTSIDE_CTOR JSFunction* canonicalSpeciesFunc_;
+#endif
+
+  // Shape of matching Array.prototype object, and slot containing the
+  // constructor for it.
+  MOZ_INIT_OUTSIDE_CTOR Shape* arrayProtoShape_;
+  MOZ_INIT_OUTSIDE_CTOR uint32_t arrayProtoConstructorSlot_;
+
+  enum class State : uint8_t {
+    // Flags marking the lazy initialization of the above fields.
+    Uninitialized,
+    Initialized,
+
+    // The disabled flag is set when we don't want to try optimizing
+    // anymore because core objects were changed.
+    Disabled
+  };
+
+  State state_ = State::Uninitialized;
+
+  // Initialize the internal fields.
+  void initialize(JSContext* cx);
+
+  // Reset the cache.
+  void reset();
+
+  // Check if the global array-related objects have not been messed with
+  // in a way that would disable this cache.
+  bool isArrayStateStillSane();
+
+ public:
+  /** Construct an |ArraySpeciesLookup| in the uninitialized state. */
+  ArraySpeciesLookup() { reset(); }
+
+  // Try to optimize the @@species lookup for an array.
+  bool tryOptimizeArray(JSContext* cx, ArrayObject* array);
+
+  // Purge the cache and all info associated with it.
+  void purge() {
+    if (state_ == State::Initialized) {
+      reset();
+    }
+  }
+};
+
+} /* namespace js */
+
+#endif /* builtin_Array_h */