mirror of
https://github.com/tianocore/edk2
synced 2026-08-27 00:23:19 -04:00
7a934d0bef
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>
42 lines
1.4 KiB
C
42 lines
1.4 KiB
C
/** @file
|
|
Define the GUID of the EDKII PI SMM memory attribute table, which
|
|
is published by PI SMM Core.
|
|
|
|
Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
|
|
SPDX-License-Identifier: BSD-2-Clause-Patent
|
|
|
|
**/
|
|
|
|
#pragma once
|
|
|
|
#define EDKII_PI_SMM_MEMORY_ATTRIBUTES_TABLE_GUID {\
|
|
0x6b9fd3f7, 0x16df, 0x45e8, {0xbd, 0x39, 0xb9, 0x4a, 0x66, 0x54, 0x1a, 0x5d} \
|
|
}
|
|
|
|
//
|
|
// The PI SMM memory attribute table contains the SMM memory map for SMM image.
|
|
//
|
|
// This table is installed to SMST as SMM configuration table.
|
|
//
|
|
// This table is published at gEfiSmmEndOfDxeProtocolGuid notification, because
|
|
// there should be no more SMM driver loaded after that. The EfiRuntimeServicesCode
|
|
// region should not be changed any more.
|
|
//
|
|
// This table is published, if and only if all SMM PE/COFF have aligned section
|
|
// as specified in UEFI specification Section 2.3. For example, IA32/X64 alignment is 4KiB.
|
|
//
|
|
// If this table is published, the EfiRuntimeServicesCode contains code only
|
|
// and it is EFI_MEMORY_RO; the EfiRuntimeServicesData contains data only
|
|
// and it is EFI_MEMORY_XP.
|
|
//
|
|
typedef struct {
|
|
UINT32 Version;
|
|
UINT32 NumberOfEntries;
|
|
UINT32 DescriptorSize;
|
|
UINT32 Reserved;
|
|
// EFI_MEMORY_DESCRIPTOR Entry[1];
|
|
} EDKII_PI_SMM_MEMORY_ATTRIBUTES_TABLE;
|
|
|
|
#define EDKII_PI_SMM_MEMORY_ATTRIBUTES_TABLE_VERSION 0x00000001
|
|
|
|
extern EFI_GUID gEdkiiPiSmmMemoryAttributesTableGuid;
|