With the toolchain splitting namespaces, ostream.h's `operator<<`
templates aren't reliably found with name lookup, likely due to the loss
of associated namespaces (zygoloid commented on this at
https://github.com/carbon-language/carbon-lang/pull/3161#discussion_r1307941999).
This is especially a barrier to moving the lex files into `Carbon::Lex`;
versus other parts of the toolchain, they contain more printable types
which are used cross-namespace, including `Carbon::Testing`. As a
consequence, I'm looking at migrating ostream.h to a more reliable
approach that doesn't rely as much on everything being in the `Carbon`
namespace.
#2569 added PrintAsID to //common/ostream.h, but given it's
explorer-specific behavior, I don't think it's the right home for it.
Noticed this while pondering better ostream interfaces.
Just opening files in vscode and seeing what clangd flags.
Some edits to ostream.h to stop it from getting flagged (the usage pattern means it's not always obviously used).
First step towards permitting declarations within namespaces. Supports only functions within namespaces for now, with no way to call those functions except from within other such functions. Unqualified lookups within a function in a namespace look in that namespace first.
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
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.
- Switch code to llvm::raw_ostream as part of standardizing output forms.
- Preferring llvm::raw_ostream over std::ostream because other tooling code should be expected to rely on llvm more closely, and an overall preference towards library consistency.
- There are a couple spots in syntax/ that still use std streams, but I'd prefer to take a separate PR to see how best to address those.
- std::boolalpha doesn't work with llvm, so I've implemented equivalent in a couple places (not enough that it felt like worth making a helper function).
- Implement Print(ostream) as consistently as we can, as an instance member.
- This facilitates the use of the common/ostream.h template to provide operators.
- Preferring this approach so that Print is easily accessible via gdb, per suggestion on #executable-semantics.
- Switch code currently calling `type->Print(ostream)` to instead do `ostream << *type`.
- Remove the unused `PrintTypeEnv`, nothing used it and the declaration didn't match the definition.
Jon Ross-Perkins
Richard SmithandJon Ross-Perkins
Geoff RomerandJon Meow
Jon Meow