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.
This follows the pattern of our main compile benchmarks, but instead of
running the compile through a library API, it does so by running a
separate process. This lets us see the performance that we would expect
from `make` or another build system invoking the compiler, as opposed to
a minimal view from the library API.
Assisted-by: Claude Code
In `SourceGenTest.IdentifierByteSumStableAcrossSeeds`, the `first`
variable was storing `llvm::StringRef`s pointing to memory allocated by
a temporary `SourceGen` instance. This memory was freed at the end of
the loop iteration, leaving `first` with dangling references that were
accessed in subsequent iterations.
Fix this by storing `std::string` copies of the identifiers in `first`
to own the memory, and use `llvm::equal` to compare them.
Assisted-by: Antigravity with Gemini
`GetIdentifiersImpl` unconditionally sliced the 64-entry
`IdentifierLengthCounts` table even for uniform distributions, which the
API documents as having no `max_length` limit. Requesting a uniform
distribution with `max_length > 64` therefore tripped an out-of-bounds
slice assertion. Only compute the table slice on the non-uniform path,
where `max_length <= 64` is already enforced.
Add `IdentifierByteSumStableAcrossSeeds`, which exercises this path (a
uniform request up to length 200) and checks the core invariant that the
total identifier byte count is independent of the random seed across a
spread of parameters.
Assisted-by: Claude Code
---------
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
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>
Implements proposal #7016: `self` moves from the deduced implicit list
(`fn F[self: Self]()`) to the front of the explicit list. Its type may
be written explicitly (`fn F(self: Self)`) or omitted, in which case it
defaults to `Self` (`fn F(self)`, `fn F(ref self)`); `self` in the
implicit list is rejected.
Throughout checking, `self` is modeled as the first explicit parameter.
Because a method is just a function whose first parameter is `self`, it
can also be called as an ordinary function with the receiver passed
explicitly (`Type.M(obj, ...)`), not only as `obj.M(...)`. A new
`SemIR::CallArgParamPatterns` helper chooses the parameters matched
against the explicit arguments, excluding a leading `self` only when it
is supplied as a method-call receiver; arity checking, conversion, and
generic deduction use it. The resulting SemIR and lowering are
unchanged: `self` is still `call_param0`, and witnesses, thunks, and
vtables are unaffected.
An omitted `self` type is parsed as a `SelfBindingPattern` node with no
type expression; checking synthesizes the `Self` type so it behaves
exactly like `self: Self`. However, the exact spelling used must match
between a forward declaration and a definition, following #3763's rules
around declaration matching.
Generated functions, thunks, and C++ interop import/export build `self`
as the first explicit parameter, and the `self`-type override (e.g.
Derived->Base for a virtual override) applies to the explicit `self`.
Placement is validated by new diagnostics: `SelfInImplicitParamList`,
`SelfNotFirstParam`, and `SelfOutsideParamList`. The benchmark source
generator and the documentation adopt the `(self)` shorthand; the
prelude, the examples, and the test data are migrated in the following
commits.
Assisted-by: Claude Code with Claude Opus 4.7
---------
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
We had source generation support for some time, but needed to get all
the runtimes set up correctly so that standard library headers are
available. Now that this is in place, we can benchmark both languages.
Also fixes a bug in the C++ source generation causing compile failures.
Assisted-by: Antigravity with Gemini
The benchmarks themselves aren't really specific to `driver`.
Keeping the source generation near to the primary use case of
benchmarking also seems like a more discoverable location.
I feel a little bad doing this reorganization right after I gave a talk
with links to a bunch of this code, but seems good to reorganize a bit
before doing some work to extend things now that we have full standard
library support for C++ benchmarking and other improvements.
Assisted-by: Antigravity with Gemini
Lucile Rose Nihlen
Chandler Carruth
