`include-what-you-use` diagnostics, in practice, are specific to
the environment's compiler and standard library. Update includes
to satisfy IWYU for our CI job under Debian 12.
To handle safely the values used by CMake variables and properties,
introduce the class cmProp as a replacement from the simple pointer
to std::string instance.
#pragma once is a widely supported compiler pragma, even though it is
not part of the C++ standard. Many of the issues keeping #pragma once
from being standardized (distributed filesystems, build farms, hard
links, etc.) do not apply to CMake - it is easy to build CMake on a
single machine. CMake also does not install any header files which can
be consumed by other projects (though cmCPluginAPI.h has been
deliberately omitted from this conversion in case anyone is still using
it.) Finally, #pragma once has been required to build CMake since at
least August 2017 (7f29bbe6 enabled server mode unconditionally, which
had been using #pragma once since September 2016 (b13d3e0d)). The fact
that we now require C++11 filters out old compilers, and it is unlikely
that there is a compiler which supports C++11 but does not support
#pragma once.
This option has been broken since commit b9f9915516 (cmMakefile: Remove
VarUsageStack., 2015-05-17, v3.3.0-rc1~52^2). That commit removed the
check that an initialized variable has actually been used and caused the
option to warn on every variable ever set. This was not caught by the
test suite because the test for the feature only checked that warnings
appear when needed and not that they do not appear when not needed.
The option was never very practical to use. Remove it to avoid the
runtime cost of usage tracking and checks for every variable (which we
were doing even when the option was not used).
Provide a standardized way to handle the C++ "standard" headers
customized to be used with current CMake C++ standard constraints.
Offer under directory `cm` headers which can be used as direct
replacements of the standard ones. For example:
#include <cm/string_view>
can be used safely for CMake development in place of the `<string_view>`
standard header.
Fixes: #19491
In cmDefinitions:
- sort methods in source code by static or not static
- use `std::unordered_set<cm::string_view>` instead of `std::set<std::string>`
for duplications tests.
- Removes `cmDefinitions::Set` method overload that takes a `const char*`
value argument.
- Updates calls to `cmDefinitions::Set` to use the `cm::string_view` based
version instead.
- The `cmDefinitions::Def` struct is simplified by removing an unused
constructor and the `std_string` type definition. The std::string value
becomes a member variable instead of being derived from.
- The `cmDefinitions::Unset` method is added that unsets a definition.
It has the same functionality as calling `cmDefinitions::Set` with a
`nullptr` value argument,
- The `cmDefinitions::Set` method gets an overloaded version that takes a
`cm::string_view` as value argument.
- The originl `cmDefinitions::Set` method with `const char*` argument is
refactored to either call the `cm::string_view` based `cmDefinitions::Set`
overload or `cmDefinitions::Unset`, depending on whether the value
`const char*` is a nullptr (`Unset`) or not (`Set`).
Suppress some cases in `Source/cmGeneratorExpressionNode.cxx` and
`Source/cmUVHandlePtr.h` where a few older compilers require a
user-defined default constructor (with `{}`).
Per-source copyright/license notice headers that spell out copyright holder
names and years are hard to maintain and often out-of-date or plain wrong.
Precise contributor information is already maintained automatically by the
version control tool. Ultimately it is the receiver of a file who is
responsible for determining its licensing status, and per-source notices are
merely a convenience. Therefore it is simpler and more accurate for
each source to have a generic notice of the license name and references to
more detailed information on copyright holders and full license terms.
Our `Copyright.txt` file now contains a list of Contributors whose names
appeared source-level copyright notices. It also references version control
history for more precise information. Therefore we no longer need to spell
out the list of Contributors in each source file notice.
Replace CMake per-source copyright/license notice headers with a short
description of the license and links to `Copyright.txt` and online information
available from "https://cmake.org/licensing". The online URL also handles
cases of modules being copied out of our source into other projects, so we
can drop our notices about replacing links with full license text.
Run the `Utilities/Scripts/filter-notices.bash` script to perform the majority
of the replacements mechanically. Manually fix up shebang lines and trailing
newlines in a few files. Manually update the notices in a few files that the
script does not handle.
Turn the feature check for cxx11_unordered_map into a function such that
we can use it for other features as well. Drop the 11 suffix, as we may
want to check features from other standards.
Run the `Utilities/Scripts/clang-format.bash` script to update
all our C++ code to a new style defined by `.clang-format`.
Use `clang-format` version 3.8.
* If you reached this commit for a line in `git blame`, re-run the blame
operation starting at the parent of this commit to see older history
for the content.
* See the parent commit for instructions to rebase a change across this
style transition commit.
Store the definitions in a cmLinkedTree in the cmMakefile. This can
be moved to cmState and then the tree will provide snapshotting
possibilities. It will also make the Closure copy created at
the start of each cmMakefile unnecesarry.
In cmMakefile::PushScope, a copy of the closure of keys initialized
in the parent scope is made. In PopScope, essentially the same copy
is inserted back into the parent. That means a lot of duplication
of strings and a lot of string comparisons. None of it is needed,
because the cmDefinitions keys already provide a canonical
representation of what is initialized.
The removal of the separate container also makes the variable handling
code more easy to reason about in general.
Before this patch, configuring llvm uses 200 KiB for the VarInitStack.
Overall peak memory consumption goes from 35.5 MiB to 35.1 MiB.
Presumably the intention here is to attempt to optimize memory by not
storing what is not needed. However, all keys need to be tracked
anyway to implement initialization tracking, and this special case
gets in the way of simplifying the implementation of that.
This doesn't change any observable effects because values set
to 0 are considered not to exist by the cmDefinitions API.
d7923b82 Use std::unordered_map instead of hash_map where available.
820777af Tests: Don't rely on ordering of targets in maps.
921d74d8 AutoGen: Don't iterate over a container while populating it.
For some reason, using recursion here is faster to configure ParaView
than using a loop. Probably some compiler optimization is inhibited
by using a loop.
Co-Author: Brad King <brad.king@kitware.com>
Construct the final list directly in a named return value. Use
a single set to track bindings already found.
Co-Author: Brad King <brad.king@kitware.com>
