Optimize the encoding of "covered" metadata by:
1. Reducing feature mask from 4 bytes to 1 byte (needs increase once we
reach more than 8 features).
2. Only emitting UAR stack args size if it is non-zero, saving 4 bytes
in the common case.
One caveat is that the emitted metadata for function PC (offset), size,
and UAR size (if enabled) are no longer aligned to 4 bytes.
SanitizerBinaryMetadata version base is increased to 2, since the change
is backwards incompatible.
Reviewed By: dvyukov
Differential Revision: https://reviews.llvm.org/D143482
For atomics metadata, we can make data race analysis more efficient by
entirely ignoring functions that include memory accesses but which only
access non-escaping (non-shared) and/or non-mutable memory. Such
functions will not be considered to be covered by "atomics" metadata,
resulting in the following benefits:
1. reduces "covered" metadata; and
2. allows data race analysis to skip such functions.
Reviewed By: dvyukov
Differential Revision: https://reviews.llvm.org/D143159
Only mark functions that have address-taken locals
as requiring UAR checking.
On a large internal app this reduces number of marked functions
from 78441 to 66618. Mostly small, trivial getter/setter-type
functions are unmarked, but also some amount of larger
number-crunching-type functions are unmarked as well.
Reviewed By: melver
Differential Revision: https://reviews.llvm.org/D139811
Currently per-function metadata consists of:
(start-pc, size, features)
This adds a new UAR feature and if it's set an additional element:
(start-pc, size, features, stack-args-size)
Reviewed By: melver
Differential Revision: https://reviews.llvm.org/D136078
