Updating to LLVM 7 mainly involved the following steps:
* Upgrade APIs for folding ConstantExpr.
* Upgrade APIs for GraphTraits.
* Upgrade APIs for DominatorTreeBase.
* Upgrade APIs for BinaryFormat to parse ELFs.
* Fix the LLVM Linker to properly link the QEMU helpers.
* Disable the new optnone attribute even with optimization -O0. This is
necessary to allow SROA to do its job properly.
* Upgrade APIs to delete Instructions.
* Properly cleaning up orphaned metadata still referring to Instructions
that have been destroyed. Recent versions of LLVM are more strict in
this respect, and will assert when compiled in debug.
* Avoid using LLVM `getGlobalContext` which has been removed from newer
versions of LLVM.
* Upgrade tests to use the new APIs.
* Upgrade APIs for instruction iterators and reverse iterators.
This commit reimplements the (conditional) reaching definitions passes
as an instance of a monotone framework.
The `ConditionNumberingPass` has also been reworked in the way it
exposes its results, but it's otherwise unchanged.
A proper unit testing framework is also available to ensure everything
works as supposed to.
Through `JumpTargetManager::setCFGForm` the `root` function CFG can be
changed so that the `dispatcher` is minimized, i.e., it jumps only to
those basic blocks that would be otherwise unreachable. This allows us
to perform more accurate and simpler analyses.
To bring the function in this state we used to check if there was at
least a non-dispatcher predecessor, however this did not work with loops
reachable only from the dispatcher, since they had a predecessor, but
that didn't mean it was reachable from the entry.
This commit fixes the problem by navigating the CFG in reverse-post
order, registering all the reachable blocks and then restoring the edge
from the dispatcher to those that are not reachable.
Additionally:
* Basic blocks with no predecessors are now purged before
`JumpTargetManager::harvest`.
* The `CFGForm` enum is now a namespace.
`InlineAsm` instructions resemble function calls. You also have to
provide the prototype of the called function. Before this commit, we
were employing `void(void)`, which was wrong since we were passing in a
CSV.
In this commit we add a pointer argument to this prototype, which
prevents an assertion in LLVM from being triggered.
Update an assertion trying to enforce the fact that `alloca`s copied
from `root` where in the original entry block, while they should be in
the `dummy` entry block.
Additionally, an improvement has been introduced which ensures only one
`alloca` is copied per-function, while, before, we were creating a new
`alloca` for each use in that function.
This commit dismisses the `argparse` library (the only non-runtime C
component of rev.ng) in favor of LLVM's CommandLine library, which
offers several benefits. Among others, now command line arguments can be
easily specified as a global variable, decentralizing their management
and avoiding the long list of arguments in the constructor of singleton
objects such as `CodeGenerator`.
This commit introduces `revng_log`, a macro analagous to `revng_assert`,
which basically allows to have the benefit of the `Logger` class without
having to compute the expression to log if the logger is disabled.
This commit also completely dismisses the `DBG` macro, converting all
the old code to `Logger` + `revng_log`.
This commit moves around most files. The new directory structure is as
follows:
* `lib/$LIBRARY/`: contains a library, i.e., a set of `.cpp` files used
by multiple libraries/tools.
* `include/revng/$LIBRARY/`: contains the public headers associated to
the library in `lib/$LIBRARY/`.
* `tools/$TOOL/`: directory where all the `.cpp` files (and private
headers) for a tool reside. Currently we have two tools: `revamb` and
`revamb-dump`.
On top of this, all file names are now in camel case.
Alessandro Di Federico