This commit drops libptc in favor of its new form libtcg.
It brings several improvements, among which:
* The QEMU version we work on has been upgraded.
* CPUStateAccessAnalysis has been reimplemented in a way that makes it
easier to debug and solves some limitations (e.g., tracking leaking
pointers).
* Identification of pieces of the CPU state that are read by each helper
and fixing access to the CPU state is now performed at build-time.
* We no longer mmap the code we need to translate, dropping all the
issues related to code that needed to be mapped where something is
already present.
* We now have two distinct flavors of helper modules: the full one and
the "slim" one. The latter contains the definition only of functions
we intend to inline. It is used in most of the pipeline, a good thing
since we spend less time optimizing code we don't really care about.
The full module is only used on the re-compilation branch of the
pipeline.
* We no longer split the `cpu_loop` function.
* We change MetaAddress to rely on architectures from `model::` as
opposed to the LLVM ones.
* We no longer attach debug info to LLVM IR containing the original
assembly.
* We now verify that the lifted code only contains code we expect.
Replace the stub implementation of invalidation with the proper
implementation. A ReadPathCache is added to each global so that it can
keep tracks of what target are associated to which read paths.
This commit improves the formalization of how we handle names.
The main changes are:
* Now `_` is a reserved prefix and all the generated names start with
`_`.
* The model verification routine now checks that `CustomName`s in the
global scope do not collide with any local namespace (e.g., fields of
a `StructType`).
* We changed the prefix `prefix_` to `unreserved_` to better convey the
fact that the prefix has been introduce to use an non-reserved name.
This commit switches `model::Type::ID` from being a GUID to be a
progressive number, in order to make things easier for humans.
On top of this, this commit introduces the following changes:
* TypeCopier: import all the necessary PrimitiveTypes and improve
handling of CustomName.
* Move Kind as the last field of the key of each TupleTree type used in
an `UpcastablePointer`.
* Update the ground truth of tests to ignore the `CustomName` in favor
of focusing on `OriginalName`.
* Increase adoption of `model::Binary::makeType`, equivalent to
`Binary.recordNewType(makeType<model::*Type>())`.
I found that it leads to better looking code when the check of whether
the range in question even has enough elements to skip is inside
the helper.
As such a separate type of skip entry point was introduced: one that
allows to iterate over the container pairwise
Now, instead of asserting, the loop just does nothing in cases like
```cpp
for (const auto &Element : zip_pairs(make_empty_range())
do_stuff();
```
`DocumentError`s are the inteded way of propagating errors from the
pipeline to the frontend when a location is required to inform the user
of the error whereabouts.
Alessandro Di Federico