Move all per-function state and logic into a new SegregateFunctionStack
worker, so the pass class itself only holds module-wide state and the
runOnFunction body is just upgrade() + segregate(). The discovery loop
now uses the MFP ExtraState surface to capture the analysis value
before each interesting program point, replacing the splitBasicBlock
trick that introduced fake nodes only to read the lattice value at
them.
Other changes that ride along:
- StackOffsetCache memoizes getStackOffset per function.
- findAllWriters does a single sorted sweep instead of a quadratic
scan over Ranges.
- The pipeline gains a stack-accesses-segregated artifact entry.
- Test fixtures (filecheck.ll, override.yml, segregate-stack-accesses
configuration) are updated to match the new IR shape.
Three closely-coupled changes that have to land together to keep
every caller compiling:
- Introduce a per-instance ExtraState recording surface (with a
NoExtraState default) and thread it through applyTransferFunction.
- Replace getMaximalFixedPoint's positional arg list with a single
MFPConfiguration struct, so callers spell out only the fields they
need.
- Replace the EntryLabels pointer with an Entry/All/vector* variant
so callers can ask for the graph entry, every node, or a custom
list without juggling extra arguments.
Update every existing caller for the new signatures and switch
Liveness::GraphType to a plain Function* (with the inverse
GraphTraits selected at call sites).
Reorganise LocalVariableBuilder so that the legacy and non-legacy
code paths are separated into two specialisations, and so that the
non-legacy specialisation does not need a model::Binary to operate.
This is a prerequisite for using LocalVariableBuilder from passes
that do not know about the model, e.g. unit tests for the new-PM
SwitchToStatements and the upcoming non-legacy decompilation
pipeline.
Extend SegregateStackAccessesPass to attach the "revng.pointers"
metadata on every llvm::Function it rewrites, and on every CallInst
it produces.
The metadata represents, in a model-agnostic way, which arguments
and return values of a call or function (both formal and actual)
are pointer-typed in the model. Later passes consume this so that
they can stay model-agnostic.
`revng_undefined_local_sp` was previously initially marked as using
inaccessible memory and, later on, marked as reading only memory.
Doing the latter right away is fine.
This commit also does not assume that function is always available.
* Make the following private headers public:
* Lift/CPUStateAccessAnalysisPass.h
* Lift/CSVOffsets.h
* Lift/PTCDump.h
* Lift/VariableManager.h
* Move from revngSupport to revngLift:
* IRAnnotators.{h,cpp}
* SelfReferencingDbgAnnotationWriter.{h,cpp}
* Move from revngSupport to revngModel:
* FunctionTags.{h,cpp}
* ProgramCounterHandler.{h,cpp}
* Move from revngSupport to revngRecompile:
* OriginalAssemblyAnnotationWriter.{h,cpp}
This reworks NameBuilder to ease the transition to the system where
the model will be guaranteed to never contain any name collisions, both
between user-specified names and the automatic ones.
This commit further centralizes the creation of allocas + ptrtoint. The
creation of these pair of instructions is problematic when the size of a
pointer in the input and target architecture differ.
In fact, in such cases, LLVM turns trunc into masking the integer to
suppresse the high bits. This results in problematic code.
This commit introduces an assumption that ensures LLVM does not do that.
Introduce LegacySegregateStackAccessesPipe
This commit restructures the SegregateStackAccesses pass and
SegregateStackAccessesPipe so that they can have 2 modes of operations:
1. Legacy, with the same behavior as the old version, injecting local
variables as custom llvm::Functions representing opcodes, such as
LocalVariable, AddressOf, StackFrameAllocator, and CallStackArguments
allocator.
2. Non-legacy, that is meant to operate with the new LocalVariableHelper
to inject local variables as regular alloca instructions, with
additional metadata to discriminate among them.
This commit renames the old SegregateStackAccessesPipe to
LegacySegregateStackAccessesPipe.
It then re-uses the old SegregateStackAccessesPipe name for a new pipe,
meant to work in non-legacy mode.
The pipeline definition YAML file is updated to keep using the legacy
version for now.
For now the implementation is still the same.
This is preliminary to unifying the creation and handling of local
variable declarations, to simplify switching over to local variables
represented by plain allocas.
Alessandro Di Federico