Add support for a common set of sanitizers supported by both
gcc and clang:
- thread
- address
- undefined
Signed-off-by: Damian Jarek <damian.jarek93@gmail.com>
local-visibility is intended to be used by libraries or targets that require
a particular visibility mode. It is not propagated to dependencies. It is
equivalent to the previous visibility feature.
The new visibility feature is a composite propagated feature, so it can be
specified by users and higher level targets as a requirement. This feature is
translated to local-visibility.
The new visibility feature can be used to specify default symbol visibility
on compilers and platforms that support it. The default visibility is
global, which matches most compilers' defaults. In gcc documentation it is
called the "default" visibility. Other modes are: protected and hidden.
* New feature <relevant> which is automatically deduced in most cases.
* Features which are not relevant do not affect target paths and
do not prevent merging of virtual targets.
* generators.jam: generator.run always returns usage-requirements
to allow usage-requirements in non-top-level generators. This
is necessary because we're using usage-requirements to track
relevance from flags.
* New rule toolset.uses-features to specify features that the rule
checks manually, instead of using toolset.flags. In the future,
we should consider restricting the properties actually passed,
to detect errors.
* Adjust tests to handle the new paths (verified by inspection).
* Add temporary option --ignore-relevance to consider all features relevant
to aid migration.
* New rule property.evaluate-conditional-relevance which helps tracking
relevance in <conditional>.
* Widely scattered changes to use the new interfaces.
This moves the built-in feature definitions into a subdirectory where each feature
(or cohesive set of features) are defined in their own file. Eventually
documentation can be added in the definitions files themselves and inported into the
full documentation. Not all features got move by this. There are some features
spread out through the toolset files. Those will also get moved as needed,
and as possible.
