This change makes the checklocks analyzer considerable more powerful, adding:
* The ability to traverse complex structures, e.g. to have multiple nested
fields as part of the annotation.
* The ability to resolve simple anonymous functions and closures, and perform
lock analysis across these invocations. This does not apply to closures that
are passed elsewhere, since it is not possible to know the context in which
they might be invoked.
* The ability to annotate return values in addition to receivers and other
parameters, with the same complex structures noted above.
* Ignoring locking semantics for "fresh" objects, i.e. objects that are
allocated in the local frame (typically a new-style function).
* Sanity checking of locking state across block transitions and returns, to
ensure that no unexpected locks are held.
Note that initially, most of these findings are excluded by a comprehensive
nogo.yaml. The findings that are included are fundamental lock violations.
The changes here should be relatively low risk, minor refactorings to either
include necessary annotations to simplify the code structure (in general
removing closures in favor of methods) so that the analyzer can be easily
track the lock state.
This change additional includes two changes to nogo itself:
* Sanity checking of all types to ensure that the binary and ast-derived
types have a consistent objectpath, to prevent the bug above from occurring
silently (and causing much confusion). This also requires a trick in
order to ensure that serialized facts are consumable downstream. This can
be removed with https://go-review.googlesource.com/c/tools/+/331789 merged.
* A minor refactoring to isolation the objdump settings in its own package.
This was originally used to implement the sanity check above, but this
information is now being passed another way. The minor refactor is preserved
however, since it cleans up the code slightly and is minimal risk.
PiperOrigin-RevId: 382613300
This is a suite of changes intended to dramatically speed up nogo speed.
First, there are minor changes that help efficiency significantly.
* Gob-based encoding is used internally, and JSON only used for the final
set of findings. This is done to preserve the existing format (which is
consumed by external tooling), and to facilitate manual debugging.
* Unnecessary regex compilation is elided in the configuration, and care is
taken for merges to prevent redundant entries. I'm not sure quite sure how,
but it turns out that this was consumed a significant amount of time,
presumably compiling the same regexes over and over again.
Second, this change enables bazel workers for nogo analyzers.
Workers enable persistent processes instead of creating and tearing down a
sandbox every invocation. A library is introduced to abstraction these details,
and allow the tools to still be written using standard flags, etc.
The key here is that these binaries and the core of nogo become aware of
caches with worker.Cache. This allows us to save significant time loading the
same set of files and findings over and over again. These caches are keyed by
the digests that are provided by bazel, and are capped in overall size.
Note that the worker package attempts to capture output during each run, but
tools are no longer permitted to write to stdout. This necessitated dropping
some spurious output from checklocks.
PiperOrigin-RevId: 370505732
This splits the nogo rules into a separate configuration yaml file, and
allows for multiple files to be provided.
Because attrs cannot be passed down to aspects, this required that all
findings are propagated up the aspect Provider. This doesn't mean that
any extra work must be done, just that this information must be carried
through the graph, and some additional starlark complexity is required.
PiperOrigin-RevId: 339076357
See tools/nogo/README.md.
The checkescape tool is able to perform recursive escape analysis, using the
actual generated binary to confirm the results produced by the compiler itself.
As an initial use case, this replaces the manual escape analysis tests used for
go_marshal, and validates that the CopyIn and CopyOut paths will not require
any allocation or stack splits.
Updates #2243
PiperOrigin-RevId: 307532986
Adin Scannell