- Subdivide toolchain/driver:driver into granular subcommand targets
(compile_subcommand, format_subcommand, lld_subcommand, etc.) to enable
independent compilation and linking.
- Decouple Target and TargetMachine options from driver headers.
- Prune unused direct dependencies across toolchain BUILD files.
Assisted-by: Antigravity with Gemini
Move `--output-last-file-only` and output filename synthesis logic out
of the general-purpose compile driver and into the `carbon compile`
subcommand, which is the only thing that should be using them. Track on
CompilationUnit whether it is being lowered, or whether it exists only
to be imported into other units.
`carbon compile` now never lowers inputs that it discovered for itself,
only inputs that were specified on the command line. In particular, it
doesn't lower (and throw away the result of lowering) the prelude any
more. This makes the toolchain tests about 10% faster in my crude
measurements.
Also, we now do not create a clang `CodeGenerator` for input files that
we are not lowering, similarly saving compilation time for units that
exist only to be imported, not lowered.
One minor change: we use the same mechanism to determine whether an
input is being lowered and to determine what the output filename is.
This means that `--phase=lower` and `--phase=optimize`, which lower but
don't produce an output file, still need an output filename to be
specified now in some cases. Given those are just debugging tools, I
think that's fine.
Assisted-by: Gemini via Antigravity
Instead of creating a CodeGenerator per CppDomain, and then crashing in
lowering when we try to consume the same llvm Module multiple times,
create a CodeGenerator for each CppFile within the domain.
For now, we mulitplex all of Clang's ASTConsumer output to all code
generators, which means that any strong external definitions within a
Carbon file (for example, in an inline `Cpp` fragment) will be emitted
to all output files in the same `CppDomain`, resulting in link errors
due to symbol redefinitions. This will be addressed later. But this
should be sufficient for Carbon compilations in which such symbols are
not defined.
We also don't yet attempt to classify which compilations will need C++
code generation, and instead create a clang `CodeGenerator` for every
Carbon file that has C++ imports. For `carbom compile`, only one Carbon
file will need code generation, and yet we still build multiple
`CodeGenerator` objects in general. Fixing this requires more plumbing
from the driver, and this will also be handled in a follow-up.
Assisted-by: Gemini via Antigravity
It's hard to track 2-space indent levels across large vertical gaps, and
it can be hard to suppress the instinct to read the dump as if it were
preorder. This change introduces a new dump mode that addresses both
problems by using box-drawing characters to explicitly represent the
parent-child edges of the tree. This new mode is the default, but the
old behavior remains available with
`--parse-dump-format=yaml-postorder`.
Instead of building one Clang `ASTContext` per compilation, the
`--share-cpp-ast` flag causes us to build a single `ASTContext` and
share it across all contexts. One new abstraction is added: `CppDomain`
represents the Carbon-side view of a Clang AST that might be shared
across multiple `SemIR::File`s. This object owns the Clang instance and
the AST.
For now, we have no isolation between the C++ state exposed to different
Carbon compilations, and we have no multiplexing of generated LLVM IR
from C++ into different Carbon compilations, so the mode is not usable
yet. The plan is to keep it behind a flag until it's ready.
Assisted-by: Gemini via Antigravity
Refactors the link driver to automatically compile and cache the carbon
prelude for use in linking.
Implements a `carbon_library` rule for compiling the Core library
dependencies in the examples.
Each file dump now starts with a `; ---` comment and ends with a blank
line. This makes it easier to visually scan the dump for a file of
interest. The comment format is somewhat arbitrary; I chose `---` to
align with the `--- filename.carbon` separator in SemIR dumps, but
without the filename, because that appears on each of the next two lines
already.
Adds `toolchain/benchmarking/prelude_benchmark.cpp`, which measures the
time to compile the Core prelude and reports the most interesting SemIR
memory statistics as benchmark counters.
The prelude is compiled by checking a file that imports it: the implicit
prelude import causes the check phase to lex, parse, and check the full
set of prelude files, so this is a direct measure of prelude compilation
cost. Four input variations exercise increasing amounts of the prelude:
an empty file, a minimal single-type use, an operator-heavy file that
hits many impls, and a compact file that pulls in a wide swath of the
prelude.
Memory usage is queried directly: `Driver::set_mem_usage` takes a
`MemUsage` that a compile merges each file's usage into; the benchmark
passes one, compiles, and sums the entries by label. A compilation unit
collects into its own `MemUsage` whenever usage is dumped or a sink is
provided (decided in `SetMultiUnitCache`); after a file is done it dumps
that `MemUsage` per-file as before and, if a sink was provided, merges
into it via a new `MemUsage::Add(const MemUsage&)` overload. `MemUsage`
also exposes its entries via a public `Entry` type and an `entries()`
accessor.
Also extends `scripts/bench_runner.py` to (1) treat Mem-prefixed
counters as cost metrics (smaller is better) and (2) tolerate metrics
that aren't reported by every benchmark in a binary.
Assisted-by: Claude Code
---------
Co-authored-by: Christopher Di Bella <cjdb.ns@gmail.com>
Support multi-file compilation, and in particular imports of files from
the prelude, in `carbon language_server`.
In order to properly interface with `CompileDriver`, also switch over to
building a proper VFS from the documents we're given.
Assisted-by: Gemini via Antigravity
This is the first draft of the implementation of
[p6333](https://docs.carbon-lang.dev/proposals/p6333.html).
The `build` subcommand shared logic with the `compile` and `link`
subcommands,
so I've moved some of the functionality in `compile` and `link` to
shared
`CompileDriver` and `LinkDriver` classes, respectively. This also
required exposing the
`CompileOptions` and `LinkOptions` subcommand structs for re-use.
There's still some work to do on the proposal, most notably the package
include automatic path resolution and import, and the refactors to
`carbon compile`.
Chandler Carruth
Richard Smith
Geoff Romer
Lucile Rose Nihlen
Lucile Rose Nihlen