Now extractvalue instruction are replaced by dedicated
OpaqueExtractValue custom opcode, that prevents LLVM from doing strange
things with extractvalues during optimizations (such as e.g. sinking).
This is important since extractvalue instructions and struct-typed
values in general in our LLVM IR are not real first-class citizens, but
only a byproduct of the binary lifting process, and they actually
represent bundles of registers that are returned from isolated
functions.
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.
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.
Change company name to "rev.ng Labs Srl" in all license headers
to reflect changed company name and legal status
Add missing license headers to files that didn't have one
Alessandro Di Federico