`ValueMaterializer` is a rewrite of what was called `AdvancedValueInfo`
which follows the same principles.
The main benefits over the old version is:
* We materialize the data-flow graph and the CFG of the relevant part of
root. This makes debugging significantly easier.
* We drop the old MonotoneFramework infrastructure in favor of
getMaximalFixedPoint.
* We significantly reduce the amount of queries we make to
AdvancedValueInfo.
We used to ignore CFEPs that matched the starting address of a basic
block of a previously detect function.
We now also exclude such CFEPs even if the candidate is *part* of an
existing block.
This commit introduces `BasicBlockID` as the unique identifier for a
`efa::BasicBlock` into the CFG. A `BasicBlockID` is defined by a
`MetaAddress` plus an incremental integer. This enables us to have
multiple instances of the same block in a single function, which is
particularly useful when inlining multiple times the same function.
Apart from this, the commit also does the following:
* It drops representing `MetaAddress`es a `structs` in the IR. This created
several issues related to ABI. We now represent them as strings.
* It defines more functions in `support.h`, instead of defining prototypes
by hand in `CodeGenerator.cpp` and the like. Specifically, `unknownPC`
and `raise_exception_helper`. We also introduce a C "constructor" for
`PlainMetaAddress`.
* It significantly reduces the API of `GeneratedCodeBasicInfo`, which
was supposed to be put on a diet since a long time. Specifically,
many jump target related methods have been moved to free functions in
`IRHelpers.h`. Also `GCBI::getSuccessors` has been pushed into its
only user, `PruneRetSuccessors`, to prevent further usage of a
deprecated API. In the future, it would be nice to drop it entirely.
* It introduces `efa::BasicBlock::InlinedFrom`.
* Introduce an enum to represent named argument indices for `newpc`.
This enables us to more effectively manipulate its argument list.
* It improves the verification and error reporting for
`efa::FunctionMetadata`.
* Update tests.
This commit is preliminary to another piece of work to improve the
generality of inlining beyond the simple "fake function" scenario, for
which the feature was originally conceived.
FunctionMetadata was being deserialized every time they were
inspected. This commit introduces a cache structure to prevent this
excessive deserializations.
The control-flow graph and all its hierarchy components
have been moved from `model` to `efa`. The CFG is now
serialized onto the LLVM IR module as a metadata.
The collection of the function entry-points has now been separated
from EarlyFunctionAnalysis into two distinct passes: the first one,
which collects functions which are in call-sites of a direct call,
and the second one which collects code pointers in `.rodata` (e.g.,
function pointers, vtables; jump-tables are possibly skipped).
Alessandro Di Federico