`DebugAnnotationWriter` creates debug information for each instruction
in the generated LLVM IR module. Before this commit, it used to clobber
any debug information in any function, which lead to wrong debug
information on helper functions.
This commit ensures that debug information of helper functions are
untouched, so that they can be used while debugging.
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 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 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