Summary:
We supported globals as sources before, but we did so by allowing ClangTrace etc. to match against any access path in the footprint of the trace.
This is very powerful/flexible, but it's ultimately not a good idea because it leads to traces that are hard to read.
This is because a footprint source doesn't have any information about its provenance: we might know that the value came from a global, but we don't know where the read occurred.
The mechanism for handling procedure calls as sources already knows how to solve this problem.
This diff implements globals as sources as a special case of procedure call sources instead.
This will give us much nicer traces with full provenance of the read from the global.
Reviewed By: mbouaziz
Differential Revision: D5772299
fbshipit-source-id: 491ae81
Summary:
In looking at summaries that Quandary took a long time to compute, one thing I notice frequently is redundancy in the footprint sources (e.g., I might see `Footprint(x), Footprint(x.f), Footprint(x*)`).
`sudo perf top` indicates that joining big sets of sources is a major performance bottleneck, and a large number of footprint sources is surely a big part of this (since we expect the number of non-footprint sources to be small).
This diff addresses the redundancy issue by using a more complex representation for a set of sources. The "known" sources are still in a set, but the footprint sources are now represented as a set of access paths (via an access trie).
The access path trie is a minimal representation of a set of access paths, so it would represent the example above as a simple `x*`.
This should make join/widen/<= faster and improve performance
Reviewed By: jberdine
Differential Revision: D5663980
fbshipit-source-id: 9fb66f8
Summary: Gflags is a popular library used to create command line arguments. Flags shouldn't flow directly to `exec` etc.
Reviewed By: jvillard, mbouaziz
Differential Revision: D5058393
fbshipit-source-id: ab062f8
Summary: A lot of C++ library functions look like this, so it's important to have.
Reviewed By: mbouaziz
Differential Revision: D5026082
fbshipit-source-id: 6f421b6
Summary:
Needed to support upcoming diff(s) that change the nature of sources/sinks in a trace. Today they are the *original* source/sink, but in the future they will be the *transitive* source/sink (last procedure to return a source/call a sink).
This new convention will make the `returnAllSources`/`callAllSinks` form of these tests not so useful, since `returnAllSources`/`callAllSinks` will now show up as a single source/sink in the trace (at least without expanding the trace). By making these tests intraprocedural, we can make sure that we're still testing everything that we want to.
Reviewed By: cristianoc
Differential Revision: D4103754
fbshipit-source-id: 1733ecf
Sam Blackshear