A simple pass that scans constant expressions and literals and
replaces them with opaque calls so that they can be easily dealt
with by the Backend, in an attempt of emitting better-looking
decompiled code.
Add an engine for running VMA in different modes. User can:
- Decide how to initialize the colors (e.g. from the Model or from
the LLVM IR)
- Decide what to do with the final TFG obtained by VMA
- Decide whether or not the Mincut algorithm should run
Candidate colors, accepted colors and content are now accessible
only with setters and getters. In this way, we can check that
the Candidates are always a subset of the Accepted colors.
1. Add a common helper to traverse ModelGEPs (`traverseModelGEP`)
2. Add a centralized way to deduce the model type of values that
have strong model information attached to them (e.g. isolated
functions and ModelGEPs)
3. Add a similar helper for deducing formal types of operands in known
cases
ModelGEP calls in LLVM IR now return an integer that has the same
size of the field being addressed by the ModelGEP.
AddressOf calls, instead, can accept any integer size as argument but
always return a pointer-sized integer.
If we find values to be used outside their scope, we need to always
mark them for assignment, so that they have a dedicated variable that
is declared in the right scope. To do this we:
1. Export the logic that decides if a value needs a top-scope variable
in a public header, to be used by both `VariableScopeAnalysis` and
`MarkAssignments`.
2. Add the `HasUsesOutsideBB` reason for assignment markers
Add `ReadsMemory` and `WritesMemory` Tags and restructure the
logic that decides whether two instructions are interfering
as follows:
1. Consider `Store`s and anything with a `WritesMemory` tag as
having side effects
2. Consider all the `TaintSet` of an instruction when deciding
if two instructions interfere
3. Consider both `ReadsMemory` and `WritesMemory` Tags when
deciding interference
Add `ReadOnly` and `InaccessibleMemOnly` attributes to the following
functions:
- `revng_stack_frame`
- `revng_call_stack_arguments`
- `ModelGEP`
- `AddressOf`
This prevents `CSE` from grouping together any of these calls, while
still enabling `DCE` to remove calls that are not used.
`DecompileFunction` now handles the opaque `parentheses` and
`ModelCast` markers as part of beautifying the decompiled code
with proper parenthesized expressions. Should OPRP not be enabled,
we fallback to the case in which parentheses are always emitted.
A simple pass that maps LLVM IR instructions to C operators,
taking into account their precedence and associativity to
emit nice-looking parenthesized expressions.
A pass that strips the casts off from some instructions, including
`ModelGEP`s, general function calls, return and store ones, and
embeds the cast into new dedicated `ModelCast` function calls.
This commit adds placeholder pointer nodes to the DLA graph during
initialization, to point to nodes that represent model types whose size
should not altered during the Middleend.
Alessandro Di Federico