Files
sdk/runtime/vm/bitfield.h
T
Samir Jindel 663a8630e6 Revert "[vm/ffi] Dispatch native callbacks through trampolines if we can't ensure callbacks will always be executable."
This reverts commit bab592fd28.

Reason for revert: Breaks SIMARM_X64 build and crashes in hot-reload.

Original change's description:
> [vm/ffi] Dispatch native callbacks through trampolines if we can't ensure callbacks will always be executable.
> 
> Issue https://github.com/dart-lang/sdk/issues/37629
> 
> Change-Id: Ib61c32bde5a8b38d90b4da77e27e3874b8bfb7e2
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/111432
> Commit-Queue: Samir Jindel <sjindel@google.com>
> Reviewed-by: Martin Kustermann <kustermann@google.com>

TBR=kustermann@google.com,alexmarkov@google.com,sjindel@google.com

Change-Id: Id7dc3068a97debc7a8f757df31ef33fb68bdcb44
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/113827
Reviewed-by: Samir Jindel <sjindel@google.com>
Commit-Queue: Samir Jindel <sjindel@google.com>
2019-08-20 16:27:32 +00:00

67 lines
2.1 KiB
C++

// Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#ifndef RUNTIME_VM_BITFIELD_H_
#define RUNTIME_VM_BITFIELD_H_
#include "platform/assert.h"
#include "platform/globals.h"
namespace dart {
static const uword kUwordOne = 1U;
// BitField is a template for encoding and decoding a value of type T
// inside a storage of type S.
template <typename S, typename T, int position, int size>
class BitField {
public:
static_assert((sizeof(S) * kBitsPerByte) >= (position + size),
"BitField does not fit into the type.");
static const intptr_t kNextBit = position + size;
// Tells whether the provided value fits into the bit field.
static bool is_valid(T value) {
return (static_cast<S>(value) & ~((kUwordOne << size) - 1)) == 0;
}
// Returns a S mask of the bit field.
static S mask() { return (kUwordOne << size) - 1; }
// Returns a S mask of the bit field which can be applied directly to
// to the raw unshifted bits.
static S mask_in_place() { return ((kUwordOne << size) - 1) << position; }
// Returns the shift count needed to right-shift the bit field to
// the least-significant bits.
static int shift() { return position; }
// Returns the size of the bit field.
static int bitsize() { return size; }
// Returns an S with the bit field value encoded.
static S encode(T value) {
ASSERT(is_valid(value));
return static_cast<S>(value) << position;
}
// Extracts the bit field from the value.
static T decode(S value) {
return static_cast<T>((value >> position) & ((kUwordOne << size) - 1));
}
// Returns an S with the bit field value encoded based on the
// original value. Only the bits corresponding to this bit field
// will be changed.
static S update(T value, S original) {
ASSERT(is_valid(value));
return (static_cast<S>(value) << position) | (~mask_in_place() & original);
}
};
} // namespace dart
#endif // RUNTIME_VM_BITFIELD_H_