This commit changes MakeSegmentRefPass so that it's now a ModulePass and
it uses the binary to detect integer constants that represent the
address of strings.
When it detects address of constant strings, instead of injecting calls
to SegmentRef, we now inject calls to cstringLiteral, so that we can
later emit them as inline string literals in C.
In segmentRef we use integer type meaning address in memory, so we
generate segmentRef function with non-pointer type. For cstringLiteral
function we need real pointer type of operand.
Save MetaAddress, size, offset and original type for every
cstringLiteral call in metadata as we do for segmentRef calls.
For cstringLiteral "revng.cstring_literal" metadata name is used.
StringLiteralPool needs tuple of address, size, offset and type to
keep distinct string decorator functions for each string. This tuple is
represented by StringLiteralPoolKey struct.
Pipe for MakeSegmentRefPass needs to be defined explicitly, because
additional wrapper passes are required in MakeSegmentRef:
1. LoadModelWrapperPass
2. LoadBinaryWrapperPass
MakeSegmentRefPass requires access to RawBinaryView to detect cstring
literals in binary.
Fix printed command in MakeSegmentRefPipe
This printed command might not work. @ale commented it will be replaced
with `revng pipe run-pipe` once we will have it.
Update IRHelpers to new revng API
Switch String and Namespace arguments in getUniqueString
Using a named metadata is simply wrong, because we need to have many of
these metadata alive at the same time with different values.
Using a named metadata has the unpleasant side effect of making all the
`SegmentRef` functions to refer to the same segment.
This commit does various things oriented at reducing the number of local
variables emitted in C:
- MarkAssignments now know that @Copy and @Assign involving
@LocalVariable only have side effects that affect the local variable
itself; this enables to reduce the number of times we're forced to
emit a local variable due to interfering side effects
- Drop the @AssignmentMarker FunctionTag; AddAssignmentMarkerPass now
doesn't emit @AssignmentMarker anymore; instead it emits groups of
@LocalVariable, @Copy, and @Assign, which benefit from the previous
point
- Drop 2 MarkAssignments::Reasons: HasManyUses and HasUsesOutsideOfBB;
both these have now been aggregated into the AlwaysAssign reason for
simplicity, representing all reasons non involving side effects
- Update BeautifyGHAST and how it reasons about side effects when
beautifying; before this commit it used @AssignmentMarker, now it
looks at @Assign
- Simplify ExitSSA; before this commit it was trying hard to be smart on
where it emitted the store instructions representing the incoming
values of the PHI that was being destroyed; this seemed smart when we
originally did it but it generated C code that was not really better
to read, so this useless complexity is finally gone
This commit adds a new pass, PrettyIntFormatting, that injects calls to
decorator functions print_hex, print_char, and print_bool around
llvm::ConstantInt in various situations.
It also updates the rest of passes of the decompilation pipelin to
understand these new decorator functions and to properly emit decorated
integer literals in the decompiled C code.
Before this commit, the code was assuming that we only passed stack
arguments to fuctions with RawFunction type. This is not true anymore.
This commit adds support to getStrongModelInfo for when we are passing
stack arguments to CABIFunctionType.
This commit removes the bugged addPointerQualifier helper function,
that was wrongly pushing the pointer qualifier at the end.
Instead, we now use the correct model::Binary::getPointerTo method.
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.
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.
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.
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.
Kacper Kołodziej