We now switch to the `llvm::df_iterator` based `nodesBetween`
implementation.
This new implementation makes use of the idiomatic way of extending the
DFS implementation provided by LLVM, instead of rolling our custom
implementation for the `nodesBetween` algorithm.
We improve the `getBackedges` and `nodesBetween` helper functions that
can be used for backedge discovery and computation of all the nodes
reachable on all the paths defined between two nodes in a graph.
We build upon the `llvm::df_iterator` function, by customizing the visit
stack to perform the desired visits.
`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.
This commit adopts `llvm::DenseSet`, `llvm::DenseMap` and
`std::unordered_set` where needed.
It also tweaks some `llvm::SmallVector` sizes.
It brings an additional ~3% improvement during lifting.
Implement a couple of restructure algorithms in a template manner, so
that they can be used with any data structure implementing
`GraphTraits`.
Test the algorithms using the `GenericGraph` data structure.
Add support for tracing onto the PipelineC. This is done by:
1. Creating wrapper functions for each PipelineC function with the
script in `scripts/PipelineC_add_tracing.py`. These will call a
special function called `wrap` which will ultimately call a method
with a `_` prepended to the name
2. Conversion of all PipelineC methods in `PipelineC.cpp` to `static`
and their rename with a `_` in front, in order for them to work with
the wrapper function in (1)
3. Generation of 2 additional include files, one for types and one for
functions, to be used by users of tracing files in order to have
introspection.
These steps allow the creation of a trace file with the use of the
`REVNG_C_API_TRACE_PATH` environment variable. The traces can then be
used in conjunction with the `revng trace run` and `revng trace
inspect` commands.
Many Pipeline objects (Globals, Ranks, Kinds, Targets in a TargetList)
were ordered by load order, this makes the playback of traces difficult.
Moreover the order of loading of pipeline files also influences the
ordering of other elements (Step, Analys{is,esLists}). These are also
ordered to prevent incosistent ordering.
This commit drops the `CallToLifted` tag in favor of a
`getCallToIsolatedFunction` function which checks if the call has the
`IsolatedFunction` tag. The function also assumes that indirect calls
are calls to lifted functions.
`getUniqueString` returns a dedup'd char array `GlobalVariable` given a
string. We used to rely on named metadata to dedup them. However, this
lead to issues with `LLVMContainer` cloning and linking.
The new implementation uses the name of the variable as the
de-decuplication key, circumventing the problem entirely and improving
performance.
Kacper Kołodziej