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>
* Remove redundant /DLL option from MSFT
* Use VERSION_STRING from [Defines] section to set
the PE/COFF optional header image version fields.
The use of the MSFT linker /VERSION option is
removed and replaced with the GenFw --image-version
option to use same method for all tool chains and
provide better error checking.
* Add CLANGPDB tool chain family support that matches
MSFT settings.
* Add GCC family tool chain support that overrides
OBJCOPY_STRIPFLAGS to nothing to prevent symbols
from being stripped from PRM Modules so the
PRM Export Descriptor Structure can be found by
GENFW when the --prm option is used.
* Remove all -Wl, options that are not compatible
across all support tool chains. This also removes
the need to list the PRM Export Descriptor Structure
and PRM Handler APIs in the INF file and instead
depend in GENFW with --prm option to find these
symbols and generate the PE/COFF DLL export section.
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Correct the GCC GenFw and ld flag to build PRM run time modules.
These changes are made for X64 GCC compiler, current present for AARCH64 only.
Adds addition _X64_OBJCOPY_STRIPFLAG for X64 to retain required symbol
during objcopy.
Signed-off-by: Abdul Lateef Attar <AbdulLateef.Attar@amd.com>
- Add the --prm flag to the GENFW_FLAGS
- Add the --no-gc-section to the linker flags so that apparently
unreferenced symbols are not prematurely removed from the .dll which
is used to generate the Prm module .efi.
- Force the linker to maintain the PrmModuleExportDescriptor symbol.
- Force the linker to maintain the PRM handler funtion's symbol.
Signed-off-by: Jose Marinho <jose.marinho@arm.com>
Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Michael Kubacki <michael.kubacki@microsoft.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
There's currently two approaches being considered for how to allocate the
context buffer passed to PRM handlers:
1. The context buffer is allocated and populated in firmware. As such, the
FW converts all pointers internal to the buffer to virtual memory
addresses at the virtual address change event. A single context buffer
pointer is given to the OS via the PRM ACPI table and the OS converts
this single physical address to a virtual address when it passes the
context buffer as a pointer to PRM handlers.
2. The context buffer is allocated and populated in the OS. The OS gets
all the information needed to populate the context buffer from other
pre-existing resources (mainly physical addresses in the PRM ACPI
table). The OS converts all the physical addresses to virtual addresses,
allocates the context buffer instances, and fills in the information.
The OS passes the context buffer virtual address to PRM handlers.
The prior behavior was (1). The current POR behavior has moved to (2).
Until (2) is used more widely, it can be kept around with fairly minimal
overhead via a build flag in a few places.
So the default behavior is now (2) (the expected permanent behavior) with
(1) easily enabled by defining "ALLOCATE_CONTEXT_BUFFER_IN_FW" in the
compiler defined macros. A DSC define was added in PrmPkg.dsc to set this
compiler macro in the package build.
At some point in the future, all code (and some peripheral code)
surrounded with this build flag can be removed if (2) is fully
decided upon.
Cc: Andrew Fish <afish@apple.com>
Cc: Kang Gao <kang.gao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Michael Kubacki <michael.kubacki@microsoft.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Benjamin You <benjamin.you@intel.com>
Cc: Liu Yun <yun.y.liu@intel.com>
Cc: Ankit Sinha <ankit.sinha@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Acked-by: Michael D Kinney <michael.d.kinney@intel.com>
Acked-by: Liming Gao <gaoliming@byosoft.com.cn>
Acked-by: Leif Lindholm <quic_llindhol@quicinc.com>
Reviewed-by: Ankit Sinha <ankit.sinha@intel.com>
