This moves over to the vanilla upstream GoogleTest pulled in the more
expected manner with Bazel. It also adds Abseil and Google Benchmark
libraries in the same fashion (there are cross dependencies here).
As part of this, also introduce a dependency check test that can enforce
basic layering of dependencies. For example, this lets us ensure that
non-test Carbon code only depends on LLVM and Clang despite having other
libraries available. There remains some cleanup to improve the way these
dependency tests work, but this at least ensures we don't regress.
I've also provided workarounds to allow both Carbon code and LLVM code
to freely be used with GoogleTest (and other `std::ostream` based
output code). This is done by extending the code in
`//common/ostream.h`. One downside is that it requires opening the
`llvm` namespace and adding an ADL_found overload there. I think on
balance this is still a win and doesn't make me too nervous.
The new version of GoogleTest requires printing more often from matchers
and so I've also added several printing routines to types that
previously didn't require them. Otherwise, most of the updates are just
using the more conventional upstream style of including the headers and
adding `ostream.h` where it is needed.
I did consider moving code over to use `std::ostream` instead of LLVM's
`raw_ostream`, but the advantages of not doing virtual dispatch still
seem significant, and it also seems good to retain access to LLVM's
formatting utilities built around `raw_ostream` given that we can't pull
arbitrary dependencies into Carbon code outside of test code.
All of this was slightly motivated by requests for newer features in
GoogleTest, but much more-so by my desire to have access to Google
Benchmark and Abseil when writing benchmarks. For example, using
Abseil's random number generator seems extremely helpful when generating
inputs for benchmarks. The growing dependencies between these packages
further motivated me to just pull them all in and ensure they worked
well.
Rationale: Based on the status of #478 and #505, Carbon won't have this feature for a while, and it will be simpler not to support it on spec in the meantime.
This does a mass rename of:
- `SourceLoc()` -> `source_loc()` for property naming
- `loc` -> `source_loc_` for underscore+consistency
- Generally changing function args to `source_loc` for consistency
- `Tag()` -> `kind()` for property naming and `Kind` parity
- `tag` -> `kind_` for underscore
Also renames `Pos` and `Results` on `Action`. These are a bit of an exception in that most base classes only have `Tag` and maybe `SourceLoc`, whereas `Action` has a little more. I felt okay having `source_loc()` and `kind()` on the base class where children do `Exp()` and the like, but it felt weird to me to mix it on the same class.
The reason for doing this cross-class in one PR is so that I can do it efficiently with a global replace in the codebase, rather than e.g. changing `Expression` but having to read through compiler errors to determine where it's calling `Expression`'s `Tag` versus a different `Tag`. The end result should be equivalent.
The advantage is a C++ pointer is special, and this approach eliminates the Ptr class type that was causing problems in conversions. Attribute suggestion was courtesy of chandlerc. We're sticking with the Ptr name because it's shorter than Nonnull, and we're likely to keep this in lots of places.
With this, only main.cpp instantiates an arena. Maybe we'll want to split that up more later (e.g., so that the runtime interpreter uses its own arena), but given the intent to have type-checking update the AST, I thought this was a reasonable approach for now in order to avoid ownership complexities.
Fixes#769
Sorry about the big change, this is hard to split. ParenContents is used by both, templated, and expects the same pointer type. While I could duplicate ParenContents with some ExpressionParenContents or PatternParenContents, that seems a little kludgy versus a single large change handling both. The worst of it is that Expression is already pretty sweeping, Pattern is really just incrementally adding.
That said, I believe this includes a couple fixes I found with incorrect use of dyn_cast in typecheck.cpp (checked nullptr at the wrong step in 2 code locations). There's also a missing `*` in member.cpp this caught. I adjust passing of expressions for Return due to nullness (I felt adding another constructor was the best solution).
I add a `.Release()` to BisonWrap due to things like `$3.first` needing some way to work through BIsonWrap. I felt this was better than `operator->`, but feel free to comment if you prefer the other path (`.Release()` conveniently lets me do pair unwrapping, so it felt a better solution).
I do add a TODO to think about better Ptr-to-Ptr cast<> support too, though, as that doesn't work cleanly with LLVM's infra. But so far it seems to only come up in one spot, so I'm not prioritizing it.
`Pattern` is intended to pilot some changes I would like to apply to all our sum types:
- The alternatives are expressed as derived classes rather than members of a `std::variant`.
- The alternatives are classes in the [style guide sense](https://google.github.io/styleguide/cppguide.html#Structs_vs._Classes), meaning they can have invariants, but can't have public data members.
- Creating an object is expressed using a constructor rather than a factory function.
- Accessing an alternative is expressed as a cast (using LLVM's RTTI system) rather than `std::get` or a `Get` method.
Co-authored-by: Jon Meow <46229924+jonmeow@users.noreply.github.com>
Chandler Carruth
Jon Meow
Geoff Romer