This fixes a subtle bug in GenericGraph. Basically, if the label of an
Edge was the Empty data structure, whose `operator==` always returns
`true`, the comparison between edges was broken.
Many old unit tests were too rigid, using the model and the LLVM IR.
This commit drops them, and replaces them with decompilation tests based
on revng-qa, relying on `revng model compare` to test model properties,
and on `FileCheck` to test that we emit specific constructs in C.
The new tests cover various features of the decompiler.
* DLA capability to recover complex data structure like linked-lists and
arrays.
* DLA capability to update segment and section types, so that we emit
nice looking accesses to segments in C.
* Capability to emit nice looking integer literals in C
* Capability to emit inline string literals in C and update the model
types of the segments containg such string literals.
This pass is dedicated to applying a bunch of peephole optimizations
that are useful for decompilation and haven't been implemented in LLVM
for whatever reason.
At the moment it only runs an optimization that tries to reduce the uses
of incoming values of PHINodes, under very specific condidtions, which
enables emitting less LocalVariables.
We used to support having a single `void` argument. It was for some
C-compatibility ambitions, but just omitting the argument is perfectly
fine.
Also, the DWARF importer has been fixed to handle typedef'd void as
arguments.
More in general, arguments are now required to always have a size.
Simplification includes dropping dependencies onto
`FunctionMetadataCachePass` and `LoadModelWrapperPass`, as well
as removing "StructName" logic outright.
This commit drops ValueManipulationAnalysis, which in its original
design based on MinCut and Karger, was never enabled in the
decompilation pipeline.
Until now, VMA was only used in a severely weakened form in
initModelTypes. That for was so weakened that it barely did anything.
We already have a new design for VMA so that it can work before
DataLayoutAnalysis, and on Clift.
At this point, the old VMA is basically useless anyway, and the very few
occasions where it can do something will simply be solved by the
upcoming work on making some of the remaining casts implicit.
At this point it does not make sense to keep VMA alive anymore.
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.
One of the two passes to purge unused types from the model had a
ill-defined semantics.
This commit simplifies them in two passes: one that purges all the types
unreachable from outside `Binary::Types` and one that does the same but
also preserves types with a `CustomName` or an `OriginalName`.
This commit drops `needsTopScopeDeclaration`.
Now all the LocalVariables are declared at the top of the function.
In DecompileFunction.cpp, the emission of LocalVariables if handled at
the scope of GHAST `ASTNode`s instead of being LLVM BasicBlock-based.
This enables in the future to design and implement an analysis that for
each LocalVariable decides the C scope (represented by an `ASTNode`)
where it's declaration should be emitted to always be visible in all its
uses.
Alessandro Di Federico