- Speedup the `varBlockReaches()` predicate, by restricting to basic blocks
in which a given SSA definition may still be live, in constrast to just
being able to reach *any* access (read or write) to the underlying source
variable.
- Account for some missing cases in the `lastRead()` predicate.
The predicate `maxSplits()` was previously applied dynamically to ensure that
any control flow node would keep track of at most `maxSplits()` number of splits.
However, there was no guarantee that two different copies of the same AST element
wouldn't contain different splits, so in general the number of copies for a given
AST element `e` could be on the order `$\binom{n}{k}c^k$`, where `n` is the total
number of splits that apply to `e`, `k = maxSplits()`, and `c` is a constant.
With this change, the relevant splits for `e` are instead computed statically,
meaning that the order is instead `$c^k$`.
When completions are inherited by elements inside `finally` blocks, we previously
threw away the underlying completion. For example, in
```
try
{
if (b)
throw new Exception();
}
finally
{
if (b)
...
}
```
the completions for `b` inside the `finally` block are `true` and `throw(Exception)`,
where the latter is inherited from the `try` block, with an underlying `false`
completion. Throwing away the `false` completion meant that we were unable to prune
the `false` edge (Boolean CFG splitting).
- Make `InstructionViolation` abstract to avoid computing `getInstructionsUpTo()`
for all instructions in the database.
- Enable `consistency.ql`, which reports all consistency violations, and remove
all other specialized tests.
- Add `Caching.qll` for controlling caching across multiple files.
- Move `isUncertainRefCall()` out of cached module in `Assignable.qll` to avoid
collapsing with CFG stage.
- Remove dependency on `AlwaysNullExpr` in `NullValue::getAnExpr()` to avoid
collapsing with CFG stage.
- Avoid caching pre-SSA library as it should only be used during the CFG construction
stage.
