There's a small fix to the mapping from 'global def -> use'.
Finally, this commit also accepts a test failure related to new missing
types for phi nodes. The fix for that is in the next commit.
This works by adding data-flow edges to skip over array expressions when
reading from arrays. On the post-update side, there was already code to
skip over array expressions when storing to arrays. That happens in
`valueToUpdate` in `AddressFlow.qll`, which needed just a small tweak to
support assignments with non-field expressions at the top-level LHS,
like `*a = ...` or `a[0] = ...`.
The new code in `AddressFlow.qll` is copy-pasted from `EscapesTree.qll`,
and there is already a note in these files saying that they share a lot
of code and must be maintained in sync.
The conflicts came from how `this` is now a parameter but not a
`Parameter` on `master`.
Conflicts:
cpp/ql/src/semmle/code/cpp/ir/dataflow/internal/DataFlowUtil.qll
cpp/ql/test/library-tests/dataflow/DefaultTaintTracking/defaulttainttracking.cpp
cpp/ql/test/library-tests/dataflow/DefaultTaintTracking/tainted.expected
cpp/ql/test/library-tests/dataflow/DefaultTaintTracking/test_diff.expected
cpp/ql/test/library-tests/dataflow/dataflow-tests/dataflow-ir-consistency.expected
cpp/ql/test/library-tests/dataflow/fields/ir-flow.expected
cpp/ql/test/library-tests/syntax-zoo/dataflow-ir-consistency.expected
g++ doesn't support this code:
sorry, unimplemented: non-trivial designated initializers not supported
twoIntFields sSwapped = { .m2 = source(), .m1 = 0 };
so we need to build it in clang mode.
This commit removes fields from the responsibilities of `FlowVar.qll`.
The treatment of fields in that file was slow and imprecise.
It then adds another copy of the shared global data flow library, used
only to find local field flow, and it exposes that local field flow
through `localFlow` and `localFlowStep`.
This has a performance cost. It adds two cached stages to any query that
uses `localFlow`: the stage from `DataFlowImplCommon`, which is shared
with all queries that use global data flow, and a new stage just for
`localFlowStep`.
