Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/js/src/jit/ScalarTypeUtils.h b/js/src/jit/ScalarTypeUtils.h
new file mode 100644
index 0000000000..19e904d9b8
--- /dev/null
+++ b/js/src/jit/ScalarTypeUtils.h
@@ -0,0 +1,41 @@
+/* -*- 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/. */
+
+#ifndef jit_ScalarTypeUtils_h
+#define jit_ScalarTypeUtils_h
+
+#include "mozilla/CheckedInt.h"
+
+#include <stdint.h>
+
+#include "js/ScalarType.h"
+
+namespace js {
+namespace jit {
+
+// Compute |index * Scalar::byteSize(type) + offsetAdjustment|. If this doesn't
+// overflow and is non-negative, return true and store the result in *offset.
+// If the computation overflows or the result is negative, false is returned and
+// *offset is left unchanged.
+[[nodiscard]] inline bool ArrayOffsetFitsInInt32(int32_t index,
+                                                 Scalar::Type type,
+                                                 int32_t offsetAdjustment,
+                                                 int32_t* offset) {
+  mozilla::CheckedInt<int32_t> val = index;
+  val *= Scalar::byteSize(type);
+  val += offsetAdjustment;
+  if (!val.isValid() || val.value() < 0) {
+    return false;
+  }
+
+  *offset = val.value();
+  return true;
+}
+
+}  // namespace jit
+}  // namespace js
+
+#endif /* jit_ScalarTypeUtils_h */