This commit is the final step in ensuring all the pipes commit what they
should. It also asserts this actually happens, enabling us to easily
catch future problems.
Before this commit, when outlining parts of `root` for analysis
purposes, we used to replace calls with a set of instructions clobbering
the set of register *not* preserved by such call, or, in case the
prototype was not available, by the default prototype.
This commit forces the usage of the default prototype.
This trades off precision with accuracy but we get the lift pipe not to
depend on any model::Function prototype.
Various parts of revng replace `llvm::GlobalVariable`s representing CSVs
with Allocal/Load/Store. In particular, these are PromoteCSV,
RootAnalyzer and PromoteGlobalToLocalVars.
Before this commit, those places were sloppy when replacing CSVs with
Alloca/Load/Store, and did that iterating on a container sorted by
pointers. This caused Alloca/Load/Store to be emitted in different order
accross runs, which in turn caused more non-determinism down the
pipeline.
This commit fixes the non-deterministic behavior, sorting CSVs based on
their names, which should always be present and deterministic.
Improve the way in which we connect the non reachable `JumpTargets` when
rebuilding the dispatcher for non `SemanticsPreserving` `CFGForm`s.
When connecting group of jump targets that are not currently reachable
from the entry dispatcher, we elect the jump target with the lowest
program counter value, as the one to be connected to the dispatcher.
We also mark the jump targets now transitively reachables from the
elected one, as reachable, so to avoid adding other unnecessary edges
from the dispatcher.
Replace the stub implementation of invalidation with the proper
implementation. A ReadPathCache is added to each global so that it can
keep tracks of what target are associated to which read paths.
`ValueMaterializer` is a rewrite of what was called `AdvancedValueInfo`
which follows the same principles.
The main benefits over the old version is:
* We materialize the data-flow graph and the CFG of the relevant part of
root. This makes debugging significantly easier.
* We drop the old MonotoneFramework infrastructure in favor of
getMaximalFixedPoint.
* We significantly reduce the amount of queries we make to
AdvancedValueInfo.
Alessandro Di Federico