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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>
49 lines
1 KiB
C
49 lines
1 KiB
C
/** @file
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Copyright (c) 2022, Arm Limited. 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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/** The size of the SMC arguments is different between AArch64 and AArch32.
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The native size is used for the arguments.
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It will be casted to either HVC or SMC args.
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*/
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typedef struct {
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UINTN Arg0;
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UINTN Arg1;
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UINTN Arg2;
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UINTN Arg3;
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UINTN Arg4;
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UINTN Arg5;
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UINTN Arg6;
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UINTN Arg7;
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UINTN Arg8;
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UINTN Arg9;
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UINTN Arg10;
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UINTN Arg11;
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UINTN Arg12;
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UINTN Arg13;
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UINTN Arg14;
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UINTN Arg15;
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UINTN Arg16;
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UINTN Arg17;
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} ARM_MONITOR_ARGS;
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/** Monitor call.
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An HyperVisor Call (HVC) or System Monitor Call (SMC) will be issued
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depending on the default conduit. PcdMonitorConduitHvc determines the type
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of the call: if true, do an HVC.
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@param [in,out] Args Arguments for the HVC/SMC.
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**/
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VOID
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EFIAPI
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ArmMonitorCall (
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IN OUT ARM_MONITOR_ARGS *Args
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);
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