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Diffstat (limited to 'js/src/jit/ScalarTypeUtils.h')
-rw-r--r-- | js/src/jit/ScalarTypeUtils.h | 41 |
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 */ |