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7835e5802a
Replace traditional `#ifndef`/`#define`/`#endif` include guards with
`#pragma` once.
`#pragma once` is a widely supported preprocessor directive that
prevents header files from being included multiple times. It is
supported by all toolchains used to build edk2: GCC, Clang/LLVM, and
MSVC.
Compared to macro-based include guards, `#pragma once`:
- Eliminates the risk of macro name collisions or copy/paste errors
where two headers inadvertently use the same guard macro.
- Eliminate inconsistency in the way include guard macros are named
(e.g., some files use `__FILE_H__`, others use `FILE_H_`, etc.).
- Reduces boilerplate (three lines replaced by one).
- Avoids polluting the macro namespace with guard symbols.
- Can improve build times as the preprocessor can skip re-opening the
file entirely, rather than re-reading it to find the matching
`#endif` ("multiple-include optimization").
- Note that some compilers may already optimize traditional include
guards, by recognzining the idiomatic pattern.
This change is made acknowledging that overall portability of the
code will technically be reduced, as `#pragma once` is not part of the
C/C++ standards.
However, this is considered acceptable given:
1. edk2 already defines a subset of supported compilers in
BaseTools/Conf/tools_def.template, all of which have supported
`#pragma once` for over two decades.
2. There have been concerns raised to the project about inconsistent
include guard naming and potential macro collisions.
Approximate compiler support dates:
- MSVC: Supported since Visual C++ 4.2 (1996)
- GCC: Supported since 3.4 (2004)
(http://gnu.ist.utl.pt/software/gcc/gcc-3.4/changes.html)
- Clang (LLVM based): Since initial release in 2007
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
138 lines
4.2 KiB
C
138 lines
4.2 KiB
C
/** @file
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Declaration of internal functions in BaseSynchronizationLib.
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Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#pragma once
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#include <Base.h>
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#include <Library/SynchronizationLib.h>
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#include <Library/BaseLib.h>
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#include <Library/DebugLib.h>
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#include <Library/TimerLib.h>
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#include <Library/PcdLib.h>
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/**
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Performs an atomic increment of an 32-bit unsigned integer.
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Performs an atomic increment of the 32-bit unsigned integer specified by
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Value and returns the incremented value. The increment operation must be
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performed using MP safe mechanisms.
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@param Value A pointer to the 32-bit value to increment.
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@return The incremented value.
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**/
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UINT32
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EFIAPI
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InternalSyncIncrement (
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IN volatile UINT32 *Value
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);
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/**
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Performs an atomic decrement of an 32-bit unsigned integer.
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Performs an atomic decrement of the 32-bit unsigned integer specified by
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Value and returns the decrement value. The decrement operation must be
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performed using MP safe mechanisms.
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@param Value A pointer to the 32-bit value to decrement.
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@return The decrement value.
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**/
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UINT32
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EFIAPI
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InternalSyncDecrement (
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IN volatile UINT32 *Value
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);
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/**
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Performs an atomic compare exchange operation on a 16-bit unsigned integer.
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Performs an atomic compare exchange operation on the 16-bit unsigned integer
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specified by Value. If Value is equal to CompareValue, then Value is set to
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ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,
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then Value is returned. The compare exchange operation must be performed using
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MP safe mechanisms.
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@param Value A pointer to the 16-bit value for the compare exchange
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operation.
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@param CompareValue A 16-bit value used in compare operation.
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@param ExchangeValue A 16-bit value used in exchange operation.
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@return The original *Value before exchange.
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**/
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UINT16
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EFIAPI
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InternalSyncCompareExchange16 (
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IN volatile UINT16 *Value,
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IN UINT16 CompareValue,
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IN UINT16 ExchangeValue
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);
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/**
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Performs an atomic compare exchange operation on a 32-bit unsigned integer.
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Performs an atomic compare exchange operation on the 32-bit unsigned integer
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specified by Value. If Value is equal to CompareValue, then Value is set to
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ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,
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then Value is returned. The compare exchange operation must be performed using
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MP safe mechanisms.
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@param Value A pointer to the 32-bit value for the compare exchange
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operation.
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@param CompareValue A 32-bit value used in compare operation.
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@param ExchangeValue A 32-bit value used in exchange operation.
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@return The original *Value before exchange.
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**/
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UINT32
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EFIAPI
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InternalSyncCompareExchange32 (
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IN volatile UINT32 *Value,
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IN UINT32 CompareValue,
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IN UINT32 ExchangeValue
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);
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/**
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Performs an atomic compare exchange operation on a 64-bit unsigned integer.
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Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
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by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and
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CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.
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The compare exchange operation must be performed using MP safe mechanisms.
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@param Value A pointer to the 64-bit value for the compare exchange
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operation.
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@param CompareValue A 64-bit value used in compare operation.
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@param ExchangeValue A 64-bit value used in exchange operation.
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@return The original *Value before exchange.
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**/
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UINT64
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EFIAPI
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InternalSyncCompareExchange64 (
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IN volatile UINT64 *Value,
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IN UINT64 CompareValue,
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IN UINT64 ExchangeValue
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);
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/**
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Internal function to retrieve the architecture specific spin lock alignment
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requirements for optimal spin lock performance.
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@return The architecture specific spin lock alignment.
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**/
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UINTN
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InternalGetSpinLockProperties (
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VOID
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);
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