Commit Graph
2053 Commits
Author SHA1 Message Date
Richard Smith 69353ed271 Basic support for incomplete types. (#3302)
Incomplete types may be nested within other types; for example, a tuple
type might have an incomplete type as an element. Handle such cases by
walking through nested incomplete types when completing a type. This is
done non-recursively in case a very complex type is formed.

Types are generally no longer completed at the point where they're
formed. Instead, we attempt to complete a type when it is used in a
context that requires a complete type, and diagnose if the type cannot
be completed at that point. This will be necessary for classes, which
can become complete after their first use, and helps tease out bugs
where a type completeness check is missing.
2023-10-17 19:30:51 +00:00
Chandler CarruthandRichard Smith 3015135a52 Skip blocks of comments with identical prefixes. (#3299)
Specifically, after lexing a comment line, look at the next line and see
if it starts with an identical sequence of indent, comment '/'s and
character after the '/'s. If so, skip it as part of a block of comments.
This skips repeatedly diagnosing the same erroneous comment introducer
after the first one in a block, but that seems like a feature rather
than a bug.

The big motivation is to make sure the lexer is minimally impacted by
the length of comment blocks and skips them as efficiently as possible.
While they aren't exactly common, large block comments do come up and
it'd be unfortunate for those to actually slow down the toolchain.

It also happens that this is particularly easy to do because we're just
looking to see if we see the same prefix byte sequence. With SIMD we can
typically handle the most common indents with just a few instructions.

Because of the diagnostic differences, I've included a scalar fallback
that replicates the functionality but has no limit on indent size or CPU
features. I've also added testing to cover this behavior.

The only non-noise benchmark changes are as expected the comment ones,
with a nice improvement across the board:

```
BM_CommentLines/1/0/0                          15.8ms ± 2%  15.6ms ± 2%   -0.87%  (p=0.004 n=19+19)
BM_CommentLines/4/0/0                          20.2ms ± 1%  18.8ms ± 1%   -6.75%  (p=0.000 n=18+18)
BM_CommentLines/128/0/0                         221ms ± 1%   167ms ± 1%  -24.44%  (p=0.000 n=20+19)
BM_CommentLines/1/30/0                         16.6ms ± 3%  16.5ms ± 3%     ~     (p=0.175 n=19+20)
BM_CommentLines/4/30/0                         26.1ms ± 1%  24.8ms ± 2%   -5.05%  (p=0.000 n=18+19)
BM_CommentLines/128/30/0                        233ms ± 1%   185ms ± 1%  -20.38%  (p=0.000 n=19+20)
BM_CommentLines/1/70/0                         19.2ms ± 1%  19.0ms ± 2%   -0.66%  (p=0.016 n=19+20)
BM_CommentLines/4/70/0                         27.9ms ± 1%  26.6ms ± 1%   -4.63%  (p=0.000 n=19+19)
BM_CommentLines/128/70/0                        251ms ± 1%   213ms ± 1%  -15.18%  (p=0.000 n=20+18)
BM_CommentLines/1/0/2                          15.9ms ± 1%  15.8ms ± 2%     ~     (p=0.061 n=19+19)
BM_CommentLines/4/0/2                          20.5ms ± 2%  19.0ms ± 2%   -7.53%  (p=0.000 n=20+20)
BM_CommentLines/128/0/2                         213ms ± 1%   153ms ± 1%  -28.18%  (p=0.000 n=19+20)
BM_CommentLines/1/30/2                         16.8ms ± 2%  16.7ms ± 3%     ~     (p=0.134 n=20+20)
BM_CommentLines/4/30/2                         26.6ms ± 1%  25.2ms ± 3%   -5.50%  (p=0.000 n=20+20)
BM_CommentLines/128/30/2                        238ms ± 1%   187ms ± 2%  -21.49%  (p=0.000 n=17+19)
BM_CommentLines/1/70/2                         19.3ms ± 1%  19.4ms ± 3%     ~     (p=0.407 n=17+20)
BM_CommentLines/4/70/2                         28.2ms ± 1%  26.9ms ± 2%   -4.70%  (p=0.000 n=19+19)
BM_CommentLines/128/70/2                        257ms ± 2%   214ms ± 1%  -16.52%  (p=0.000 n=20+18)
BM_CommentLines/1/0/8                          16.3ms ± 2%  16.1ms ± 2%   -1.22%  (p=0.001 n=20+20)
BM_CommentLines/4/0/8                          22.7ms ± 2%  20.4ms ± 2%  -10.20%  (p=0.000 n=20+20)
BM_CommentLines/128/0/8                         244ms ± 1%   153ms ± 1%  -37.26%  (p=0.000 n=20+18)
BM_CommentLines/1/30/8                         17.3ms ± 2%  17.2ms ± 3%     ~     (p=0.192 n=20+20)
BM_CommentLines/4/30/8                         28.0ms ± 2%  25.6ms ± 3%   -8.46%  (p=0.000 n=19+18)
BM_CommentLines/128/30/8                        272ms ± 1%   196ms ± 2%  -27.90%  (p=0.000 n=18+20)
BM_CommentLines/1/70/8                         19.9ms ± 2%  19.9ms ± 2%     ~     (p=0.531 n=20+19)
BM_CommentLines/4/70/8                         29.3ms ± 1%  27.3ms ± 1%   -6.87%  (p=0.000 n=19+19)
BM_CommentLines/128/70/8                        292ms ± 1%   228ms ± 1%  -21.97%  (p=0.000 n=20+19)
```

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2023-10-17 16:07:03 +00:00
Chandler Carruth 7371354dc7 Consolidate indent handling to following newlines. (#3298)
The biggest advantage of this is reducing the repeated code in every
non-whitespace code path of the lexer to set indent appropriately. Now
we handle it cleanly at the start and after vertical whitespace.

While this makes the generated code for all the other paths through the
lexer quite a bit nicer, it doesn't actually move performance in
interesting ways outside of making large blocks of blank lines slightly
slower. While there are lots of fluctuations in the benchmark data, they
mostly seem to be either noise or artifacts of loop alignment and not
really due to an important change here.

Raw benchmark data:

```
BM_ValidKeywords                               3.10ms ± 1%   3.13ms ± 1%   +1.02%  (p=0.000 n=20+19)
BM_ValidIdentifiers<1, 64, false>              10.8ms ± 3%   10.7ms ± 3%     ~     (p=0.383 n=20+20)
BM_ValidIdentifiers<1, 1, true>                3.71ms ± 1%   3.67ms ± 2%   -1.05%  (p=0.000 n=19+19)
BM_ValidIdentifiers<3, 5, true>                13.1ms ± 2%   13.0ms ± 2%     ~     (p=0.120 n=20+19)
BM_ValidIdentifiers<3, 16, true>               13.1ms ± 2%   13.2ms ± 2%     ~     (p=0.091 n=20+20)
BM_ValidIdentifiers<12, 64, true>              15.1ms ± 1%   15.1ms ± 1%     ~     (p=0.138 n=19+19)
BM_HorizontalWhitespace/1                      13.2ms ± 3%   13.2ms ± 0%     ~     (p=0.458 n=20+15)
BM_HorizontalWhitespace/4                      13.4ms ± 3%   13.3ms ± 1%   -1.12%  (p=0.000 n=20+19)
BM_HorizontalWhitespace/16                     14.1ms ± 2%   14.0ms ± 2%   -0.89%  (p=0.010 n=20+20)
BM_HorizontalWhitespace/64                     17.9ms ± 2%   17.8ms ± 1%   -0.73%  (p=0.002 n=20+16)
BM_HorizontalWhitespace/128                    24.2ms ± 2%   24.1ms ± 1%     ~     (p=0.346 n=19+17)
BM_RandomSource                                7.88ms ± 2%   7.83ms ± 3%     ~     (p=0.052 n=20+20)
BM_GroupingSymbols/1/0/0                       6.25ms ± 2%   6.38ms ± 1%   +1.99%  (p=0.000 n=20+19)
BM_GroupingSymbols/2/0/0                       5.24ms ± 2%   5.27ms ± 2%     ~     (p=0.065 n=20+19)
BM_GroupingSymbols/3/0/0                       4.09ms ± 1%   4.07ms ± 1%     ~     (p=0.063 n=20+20)
BM_GroupingSymbols/4/0/0                       3.80ms ± 1%   3.79ms ± 2%     ~     (p=0.820 n=20+20)
BM_GroupingSymbols/8/0/0                       3.05ms ± 1%   3.09ms ± 1%   +1.41%  (p=0.000 n=20+20)
BM_GroupingSymbols/16/0/0                      2.95ms ± 1%   3.01ms ± 1%   +1.79%  (p=0.000 n=20+20)
BM_GroupingSymbols/32/0/0                      3.67ms ± 1%   3.77ms ± 1%   +2.75%  (p=0.000 n=20+20)
BM_GroupingSymbols/0/1/0                       5.66ms ± 1%   5.61ms ± 1%   -0.88%  (p=0.000 n=20+18)
BM_GroupingSymbols/0/2/0                       4.43ms ± 2%   4.40ms ± 1%   -0.74%  (p=0.005 n=20+17)
BM_GroupingSymbols/0/3/0                       3.15ms ± 2%   3.12ms ± 2%   -0.96%  (p=0.002 n=20+19)
BM_GroupingSymbols/0/4/0                       2.79ms ± 2%   2.77ms ± 2%   -0.88%  (p=0.005 n=20+20)
BM_GroupingSymbols/0/8/0                       1.81ms ± 2%   1.79ms ± 2%     ~     (p=0.056 n=20+20)
BM_GroupingSymbols/0/16/0                      1.26ms ± 2%   1.26ms ± 2%     ~     (p=0.547 n=20+20)
BM_GroupingSymbols/0/32/0                      1.05ms ± 1%   0.96ms ± 1%   -8.52%  (p=0.000 n=19+19)
BM_GroupingSymbols/0/0/1                       5.68ms ± 2%   5.65ms ± 2%     ~     (p=0.126 n=20+18)
BM_GroupingSymbols/0/0/2                       4.44ms ± 2%   4.40ms ± 2%   -0.99%  (p=0.001 n=20+18)
BM_GroupingSymbols/0/0/3                       3.15ms ± 1%   3.13ms ± 1%   -0.74%  (p=0.005 n=20+18)
BM_GroupingSymbols/0/0/4                       2.80ms ± 1%   2.77ms ± 2%   -1.01%  (p=0.000 n=20+19)
BM_GroupingSymbols/0/0/8                       1.81ms ± 2%   1.79ms ± 2%   -0.97%  (p=0.006 n=20+20)
BM_GroupingSymbols/0/0/16                      1.26ms ± 1%   1.26ms ± 2%     ~     (p=0.678 n=20+20)
BM_GroupingSymbols/0/0/32                      1.05ms ± 1%   0.96ms ± 1%   -8.59%  (p=0.000 n=20+19)
BM_GroupingSymbols/32/1/0                      3.57ms ± 1%   3.69ms ± 1%   +3.39%  (p=0.000 n=19+20)
BM_GroupingSymbols/32/2/0                      3.49ms ± 1%   3.60ms ± 1%   +3.16%  (p=0.000 n=20+20)
BM_GroupingSymbols/32/3/0                      3.41ms ± 1%   3.52ms ± 1%   +3.49%  (p=0.000 n=19+20)
BM_GroupingSymbols/32/4/0                      3.35ms ± 1%   3.45ms ± 1%   +3.13%  (p=0.000 n=20+20)
BM_GroupingSymbols/32/8/0                      3.12ms ± 1%   3.22ms ± 1%   +3.09%  (p=0.000 n=19+20)
BM_GroupingSymbols/32/16/0                     2.75ms ± 1%   2.82ms ± 1%   +2.71%  (p=0.000 n=19+20)
BM_GroupingSymbols/32/32/0                     2.24ms ± 2%   2.24ms ± 1%     ~     (p=0.311 n=20+17)
BM_GroupingSymbols/32/32/1                     2.20ms ± 1%   2.23ms ± 1%   +1.23%  (p=0.000 n=20+20)
BM_GroupingSymbols/32/32/2                     2.19ms ± 1%   2.21ms ± 1%   +1.08%  (p=0.000 n=20+20)
BM_GroupingSymbols/32/32/3                     2.16ms ± 0%   2.19ms ± 1%   +1.09%  (p=0.000 n=18+20)
BM_GroupingSymbols/32/32/4                     2.14ms ± 1%   2.19ms ± 1%   +2.25%  (p=0.000 n=20+20)
BM_GroupingSymbols/32/32/8                     2.07ms ± 1%   2.11ms ± 1%   +2.04%  (p=0.000 n=17+20)
BM_GroupingSymbols/32/32/16                    1.94ms ± 1%   1.98ms ± 1%   +1.95%  (p=0.000 n=20+20)
BM_GroupingSymbols/32/32/32                    1.74ms ± 1%   1.77ms ± 1%   +1.88%  (p=0.000 n=18+20)
BM_BlankLines/1                                14.2ms ± 1%   14.4ms ± 1%   +1.47%  (p=0.000 n=18+16)
BM_BlankLines/4                                17.3ms ± 1%   17.5ms ± 2%   +1.32%  (p=0.000 n=17+20)
BM_BlankLines/16                               31.3ms ± 1%   33.0ms ± 2%   +5.35%  (p=0.000 n=19+20)
BM_BlankLines/64                               89.6ms ± 1%  101.3ms ± 1%  +12.98%  (p=0.000 n=20+20)
BM_BlankLines/128                               167ms ± 3%    185ms ± 1%  +11.11%  (p=0.000 n=19+20)
BM_CommentLines/1/0/0                          15.7ms ± 1%   15.8ms ± 1%     ~     (p=0.109 n=19+16)
BM_CommentLines/4/0/0                          19.8ms ± 1%   20.2ms ± 1%   +2.12%  (p=0.000 n=20+19)
BM_CommentLines/128/0/0                         208ms ± 1%    221ms ± 1%   +6.29%  (p=0.000 n=20+19)
BM_CommentLines/1/30/0                         16.6ms ± 1%   16.6ms ± 1%     ~     (p=0.354 n=19+19)
BM_CommentLines/4/30/0                         25.8ms ± 2%   26.1ms ± 1%   +1.39%  (p=0.000 n=20+19)
BM_CommentLines/128/30/0                        222ms ± 2%    232ms ± 1%   +4.46%  (p=0.000 n=20+18)
BM_CommentLines/1/70/0                         19.2ms ± 2%   19.1ms ± 1%     ~     (p=0.478 n=20+19)
BM_CommentLines/4/70/0                         27.6ms ± 2%   27.9ms ± 1%   +0.95%  (p=0.001 n=20+18)
BM_CommentLines/128/70/0                        245ms ± 2%    250ms ± 1%   +1.96%  (p=0.000 n=20+18)
BM_CommentLines/1/0/2                          16.0ms ± 1%   15.9ms ± 2%   -0.68%  (p=0.015 n=15+18)
BM_CommentLines/4/0/2                          20.6ms ± 1%   20.5ms ± 1%   -0.53%  (p=0.024 n=18+19)
BM_CommentLines/128/0/2                         216ms ± 2%    213ms ± 1%   -1.70%  (p=0.000 n=17+19)
BM_CommentLines/1/30/2                         16.9ms ± 2%   16.8ms ± 3%     ~     (p=0.072 n=20+20)
BM_CommentLines/4/30/2                         26.8ms ± 2%   26.5ms ± 1%   -0.91%  (p=0.000 n=20+19)
BM_CommentLines/128/30/2                        244ms ± 2%    238ms ± 1%   -2.30%  (p=0.000 n=19+17)
BM_CommentLines/1/70/2                         19.4ms ± 2%   19.4ms ± 2%     ~     (p=0.059 n=18+20)
BM_CommentLines/4/70/2                         28.4ms ± 2%   28.2ms ± 1%   -0.81%  (p=0.003 n=20+19)
BM_CommentLines/128/70/2                        261ms ± 2%    255ms ± 1%   -2.33%  (p=0.000 n=20+18)
BM_CommentLines/1/0/8                          16.2ms ± 2%   16.2ms ± 2%     ~     (p=0.904 n=20+20)
BM_CommentLines/4/0/8                          25.0ms ± 1%   22.6ms ± 1%   -9.40%  (p=0.000 n=20+19)
BM_CommentLines/128/0/8                         246ms ± 2%    244ms ± 1%   -1.14%  (p=0.000 n=20+19)
BM_CommentLines/1/30/8                         17.3ms ± 2%   17.3ms ± 1%     ~     (p=1.000 n=19+18)
BM_CommentLines/4/30/8                         30.3ms ± 2%   27.9ms ± 1%   -7.83%  (p=0.000 n=20+20)
BM_CommentLines/128/30/8                        277ms ± 3%    271ms ± 1%   -2.26%  (p=0.000 n=20+17)
BM_CommentLines/1/70/8                         19.9ms ± 2%   19.9ms ± 2%     ~     (p=0.687 n=19+20)
BM_CommentLines/4/70/8                         31.7ms ± 2%   29.3ms ± 1%   -7.55%  (p=0.000 n=20+18)
BM_CommentLines/128/70/8                        296ms ± 2%    291ms ± 1%   -1.50%  (p=0.000 n=20+18)
```
2023-10-16 16:54:05 +00:00
Richard SmithandChandler Carruth e4caf7d604 Compute and cache the value representation of a type when it becomes complete. (#3271)
Using the computed value representation, fix lowering of struct and
tuple values to use the value representation rather than the object
representation. Fixes an issue found in the review of #3257.

This currently causes us to compute value representations of all types
as they are created, which generates substantially more SemIR to
represent types. We can get some of that back by deferring computation
of the value representation until the type is required to be complete,
but some of the additional cost here will persist with this approach.

I also considered making the computation of the value representation
type be something that lives entirely within the lowering phase, but I
think that's not the right approach in the longer term, because the
value representation will be semantically visible and relevant once we
start allowing it to be customized.

We should consider moving the nodes that exist to compute canonical
non-local types, including value representations, out into a separate
global block. That will clean up the SemIR representation substantially,
and make the SemIR produced for a function not depend on which types we
happen to have encountered beforehand. But that's not being done in this
PR.

---------

Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2023-10-13 22:27:02 +00:00
Richard Smith 1ae5fe0cd5 Provide the callee expression to the Call node. (#3291)
Track the callee expression in full, instead of only tracking the
callee's FunctionId. This results in the `name_reference` denoting the
function actually being used.

Lowering now propagates a `llvm::Function*` as the value associated with
expressions of type `<function>`.

We were not creating `NameReference` node for names produced by member
access into a namespace, such as the second name in
`Namespace.Function`, which caused lowering of calls to such names to
fail. This is now fixed, but the resulting `NameReference` node only
refers to the name and the lookup result, not to the `Namespace.`
qualifier. We'll need to decide how to fit a third operand into that
node (perhaps we can stop storing the `name_id`, since it can be derived
from the lookup result) but for now the qualifier is not tracked.
2023-10-13 22:06:23 +00:00
Richard Smith c61b6a0e1d Rename //toolchain/sem_ir:file_test -> :yaml_test. (#3293)
While this test is testing //toolchain/sem_ir:file, the interesting
thing about it is that it's testing the YAML output from File printing.
Calling this test `:file_test` is also deeply confusing because that's
also the name we give to all of our tests that are testing the files in
`testdata/`, which is not what this test does.
2023-10-13 21:47:16 +00:00
josh11bandRichard Smith a112f2e802 Validate parse nodes correspond to expected tokens (#3295)
Can specify which tokens are allowed generally, and any additional
tokens that only occur when the parse node has an error.

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2023-10-13 21:44:51 +00:00
Chandler Carruth 95a1cc8cba Tweak lexer to improve generated code. (#3296)
This is a collection of tweaks and they are ones I'm less confident in
FWIW. I set out to make the generated code cleaner and reduce loading
pointers through pointers in a bunch of cases. It also works to reduce
the working-set-size, and reduce the set of mutated values on each
iteration. But I didn't benchmark at each step and it's not clear that
incremental benchmarks will even be meaningful, so its hard to say which
tweaks were load bearing and which weren't.

For example, with this, the core lexer dispatch loop doesn't mutate
anything in memory -- the position is passed in register and incremented
in register throughout. The pointer to the source text, the size, and
the pointer to the lexer are also passed in registers.

By making the tokenized buffer a direct member of the lexer, all of its
members can be accessed at a constant offset from the lexer pointer
itself. The cost of this is a move at the end of lexing, but especially
as the buffer size gets large this seems like a trivial cost compared to
the previous double-indirection.

This uses a (significantly) cheaper representation for the line index --
the `Line` type is optimized for dense *storage*, and is not a great
type for using in a tight loop like the lexer. Once using a good index
and once the line table is readily available from the above, we can
simply index the line table rather than store (and update) a separate
pointer.

Last but not least, this removes the column as suggested in a previous
review. Now it is computed from the position and the line information.

My macro benchmark looks like it improves in the 2% - 5% range, but its
getting into the noise sadly (or maybe this is good?).

On a quiet AMD server with 20 runs before/after I get reasonably
compelling across-the-board improvements on all the microbenchmarks,
including 5% on `RandomSource` which is key:

```
BM_ValidKeywords                               3.44ms ± 1%  3.11ms ± 1%   -9.52%  (p=0.000 n=19+20)
BM_ValidIdentifiers<1, 64, false>              11.2ms ± 1%  10.8ms ± 2%   -3.23%  (p=0.000 n=19+20)
BM_ValidIdentifiers<1, 1, true>                3.96ms ± 1%  3.72ms ± 1%   -6.10%  (p=0.000 n=18+20)
BM_ValidIdentifiers<3, 5, true>                13.5ms ± 1%  13.2ms ± 3%   -2.45%  (p=0.000 n=19+20)
BM_ValidIdentifiers<3, 16, true>               13.5ms ± 2%  13.1ms ± 2%   -2.81%  (p=0.000 n=19+20)
BM_ValidIdentifiers<12, 64, true>              15.6ms ± 1%  15.2ms ± 3%   -2.41%  (p=0.000 n=19+20)
BM_HorizontalWhitespace/1                      13.6ms ± 2%  13.3ms ± 3%   -2.34%  (p=0.000 n=19+20)
BM_HorizontalWhitespace/4                      13.9ms ± 2%  13.6ms ± 3%   -2.06%  (p=0.000 n=19+20)
BM_HorizontalWhitespace/16                     14.5ms ± 2%  14.3ms ± 2%   -1.17%  (p=0.002 n=19+20)
BM_HorizontalWhitespace/64                     18.5ms ± 3%  18.1ms ± 2%   -2.17%  (p=0.000 n=19+19)
BM_HorizontalWhitespace/128                    24.7ms ± 1%  24.4ms ± 2%   -1.29%  (p=0.000 n=18+20)
BM_RandomSource                                8.38ms ± 2%  7.92ms ± 2%   -5.50%  (p=0.000 n=19+20)
BM_GroupingSymbols/1/0/0                       6.63ms ± 2%  6.30ms ± 2%   -4.97%  (p=0.000 n=19+20)
BM_GroupingSymbols/2/0/0                       5.65ms ± 2%  5.27ms ± 2%   -6.75%  (p=0.000 n=19+20)
BM_GroupingSymbols/3/0/0                       4.51ms ± 1%  4.12ms ± 1%   -8.62%  (p=0.000 n=19+18)
BM_GroupingSymbols/4/0/0                       4.23ms ± 1%  3.82ms ± 1%   -9.65%  (p=0.000 n=19+18)
BM_GroupingSymbols/8/0/0                       3.50ms ± 1%  3.08ms ± 1%  -12.21%  (p=0.000 n=19+19)
BM_GroupingSymbols/16/0/0                      3.38ms ± 1%  2.97ms ± 1%  -11.98%  (p=0.000 n=19+19)
BM_GroupingSymbols/32/0/0                      4.10ms ± 1%  3.69ms ± 1%  -10.02%  (p=0.000 n=17+19)
BM_GroupingSymbols/0/1/0                       5.85ms ± 2%  5.70ms ± 1%   -2.54%  (p=0.000 n=19+20)
BM_GroupingSymbols/0/2/0                       4.60ms ± 2%  4.46ms ± 1%   -3.12%  (p=0.000 n=19+19)
BM_GroupingSymbols/0/3/0                       3.32ms ± 2%  3.18ms ± 1%   -4.21%  (p=0.000 n=18+20)
BM_GroupingSymbols/0/4/0                       2.94ms ± 2%  2.82ms ± 1%   -4.22%  (p=0.000 n=19+20)
BM_GroupingSymbols/0/8/0                       1.95ms ± 1%  1.83ms ± 1%   -6.47%  (p=0.000 n=17+19)
BM_GroupingSymbols/0/16/0                      1.40ms ± 1%  1.27ms ± 1%   -9.12%  (p=0.000 n=19+20)
BM_GroupingSymbols/0/32/0                      1.19ms ± 1%  1.05ms ± 1%  -11.50%  (p=0.000 n=19+20)
BM_GroupingSymbols/0/0/1                       5.88ms ± 2%  5.71ms ± 1%   -2.87%  (p=0.000 n=19+20)
BM_GroupingSymbols/0/0/2                       4.62ms ± 1%  4.45ms ± 2%   -3.58%  (p=0.000 n=18+20)
BM_GroupingSymbols/0/0/3                       3.32ms ± 1%  3.17ms ± 1%   -4.72%  (p=0.000 n=16+17)
BM_GroupingSymbols/0/0/4                       2.95ms ± 1%  2.81ms ± 2%   -4.50%  (p=0.000 n=16+19)
BM_GroupingSymbols/0/0/8                       1.96ms ± 1%  1.82ms ± 2%   -6.80%  (p=0.000 n=19+20)
BM_GroupingSymbols/0/0/16                      1.40ms ± 1%  1.27ms ± 1%   -8.96%  (p=0.000 n=19+20)
BM_GroupingSymbols/0/0/32                      1.19ms ± 1%  1.05ms ± 1%  -11.64%  (p=0.000 n=19+20)
BM_GroupingSymbols/32/1/0                      4.04ms ± 1%  3.60ms ± 1%  -10.81%  (p=0.000 n=17+20)
BM_GroupingSymbols/32/2/0                      3.93ms ± 1%  3.51ms ± 1%  -10.55%  (p=0.000 n=18+20)
BM_GroupingSymbols/32/3/0                      3.84ms ± 1%  3.44ms ± 1%  -10.38%  (p=0.000 n=18+19)
BM_GroupingSymbols/32/4/0                      3.76ms ± 2%  3.38ms ± 1%  -10.21%  (p=0.000 n=19+20)
BM_GroupingSymbols/32/8/0                      3.51ms ± 1%  3.14ms ± 1%  -10.61%  (p=0.000 n=19+19)
BM_GroupingSymbols/32/16/0                     3.11ms ± 1%  2.77ms ± 1%  -10.95%  (p=0.000 n=19+20)
BM_GroupingSymbols/32/32/0                     2.54ms ± 2%  2.25ms ± 1%  -11.77%  (p=0.000 n=19+16)
BM_GroupingSymbols/32/32/1                     2.50ms ± 1%  2.22ms ± 2%  -11.19%  (p=0.000 n=19+20)
BM_GroupingSymbols/32/32/2                     2.48ms ± 1%  2.21ms ± 1%  -11.15%  (p=0.000 n=19+20)
BM_GroupingSymbols/32/32/3                     2.46ms ± 1%  2.18ms ± 1%  -11.11%  (p=0.000 n=18+20)
BM_GroupingSymbols/32/32/4                     2.43ms ± 1%  2.16ms ± 1%  -11.04%  (p=0.000 n=19+20)
BM_GroupingSymbols/32/32/8                     2.35ms ± 1%  2.09ms ± 1%  -11.11%  (p=0.000 n=19+20)
BM_GroupingSymbols/32/32/16                    2.20ms ± 1%  1.96ms ± 1%  -11.30%  (p=0.000 n=19+18)
BM_GroupingSymbols/32/32/32                    1.98ms ± 1%  1.75ms ± 1%  -11.54%  (p=0.000 n=19+19)
BM_BlankLines/1                                14.6ms ± 1%  14.2ms ± 3%   -2.53%  (p=0.000 n=19+19)
BM_BlankLines/4                                18.3ms ± 1%  17.4ms ± 2%   -4.68%  (p=0.000 n=19+20)
BM_BlankLines/16                               34.9ms ± 2%  31.6ms ± 3%   -9.42%  (p=0.000 n=19+20)
BM_BlankLines/64                                102ms ± 2%    91ms ± 3%  -10.75%  (p=0.000 n=19+20)
BM_BlankLines/128                               190ms ± 2%   169ms ± 3%  -10.82%  (p=0.000 n=19+20)
BM_CommentLines/1/0/0                          16.2ms ± 1%  15.8ms ± 2%   -2.29%  (p=0.000 n=19+19)
BM_CommentLines/4/0/0                          21.0ms ± 1%  19.9ms ± 2%   -5.17%  (p=0.000 n=19+19)
BM_CommentLines/128/0/0                         237ms ± 1%   211ms ± 2%  -10.93%  (p=0.000 n=19+20)
BM_CommentLines/1/30/0                         17.0ms ± 1%  16.8ms ± 3%   -1.36%  (p=0.001 n=17+20)
BM_CommentLines/4/30/0                         27.2ms ± 2%  26.0ms ± 2%   -4.24%  (p=0.000 n=19+20)
BM_CommentLines/128/30/0                        255ms ± 2%   223ms ± 2%  -12.58%  (p=0.000 n=19+20)
BM_CommentLines/1/70/0                         19.7ms ± 1%  19.2ms ± 1%   -2.35%  (p=0.000 n=18+18)
BM_CommentLines/4/70/0                         29.0ms ± 2%  27.6ms ± 1%   -4.81%  (p=0.000 n=18+17)
BM_CommentLines/128/70/0                        273ms ± 7%   249ms ± 3%   -9.05%  (p=0.000 n=20+20)
BM_CommentLines/1/0/2                          16.4ms ± 2%  16.0ms ± 1%   -2.49%  (p=0.000 n=19+15)
BM_CommentLines/4/0/2                          22.0ms ± 2%  20.7ms ± 1%   -5.84%  (p=0.000 n=19+17)
BM_CommentLines/128/0/2                         256ms ± 2%   218ms ± 1%  -14.88%  (p=0.000 n=19+17)
BM_CommentLines/1/30/2                         17.4ms ± 1%  17.0ms ± 2%   -2.26%  (p=0.000 n=19+19)
BM_CommentLines/4/30/2                         28.5ms ± 1%  26.9ms ± 2%   -5.67%  (p=0.000 n=19+18)
BM_CommentLines/128/30/2                        288ms ± 5%   246ms ± 3%  -14.70%  (p=0.000 n=19+20)
BM_CommentLines/1/70/2                         19.9ms ± 1%  19.4ms ± 1%   -2.56%  (p=0.000 n=19+18)
BM_CommentLines/4/70/2                         30.0ms ± 2%  28.5ms ± 2%   -5.20%  (p=0.000 n=19+19)
BM_CommentLines/128/70/2                        300ms ± 3%   265ms ± 3%  -11.69%  (p=0.000 n=18+20)
BM_CommentLines/1/0/8                          16.7ms ± 2%  16.3ms ± 2%   -2.22%  (p=0.000 n=19+19)
BM_CommentLines/4/0/8                          26.4ms ± 1%  25.2ms ± 1%   -4.42%  (p=0.000 n=19+18)
BM_CommentLines/128/0/8                         285ms ± 2%   248ms ± 1%  -13.16%  (p=0.000 n=19+18)
BM_CommentLines/1/30/8                         17.9ms ± 2%  17.4ms ± 1%   -2.99%  (p=0.000 n=19+17)
BM_CommentLines/4/30/8                         32.0ms ± 1%  30.5ms ± 2%   -4.73%  (p=0.000 n=19+20)
BM_CommentLines/128/30/8                        320ms ± 2%   280ms ± 3%  -12.52%  (p=0.000 n=18+20)
BM_CommentLines/1/70/8                         20.7ms ± 2%  20.0ms ± 2%   -3.22%  (p=0.000 n=19+19)
BM_CommentLines/4/70/8                         33.5ms ± 2%  31.8ms ± 1%   -5.23%  (p=0.000 n=19+19)
BM_CommentLines/128/70/8                        338ms ± 3%   298ms ± 2%  -11.64%  (p=0.000 n=19+20)
```
2023-10-13 21:30:24 +00:00
Richard Smith 4e64b1948d Bare-bones support for forward-declared classes. (#3294)
This is mostly scaffolding, but is just about enough for pointers to
classes to work properly as types.
2023-10-13 21:29:50 +00:00
Chandler Carruth 0e2b6c7f1a Optimize runs of horizontal whitespace. (#3288)
So, this is a somewhat fun, simple improvement. =] Just use a loop and
count runs of whitespace. I didn't even work all that hard to make the
loop fast, but it seems great. Makes long runs of indentation more than
2x faster at basically no code complexity.

I thought about doing this for vertical whitespace as well but it's not
easy to do, and didn't seem worth adding complexity. Huge runs of blank
lines aren't nearly as common as lots of indentation. I do have a plan
for an analogous optimization for comment blocks, but want to simplify
some other code first.

We could also make this (hilariously) faster with some judicious use of
SIMD or clever use of a string function, but it doesn't seem worth it
given how fast the simple loop is already.

I didn't work to get a high N count and so there's plenty of noise here,
but the benchmark data speaks for itself:

```
BM_ValidKeywords                               2.71ms ± 1%  2.75ms ± 1%   +1.32%  (p=0.016 n=5+5)
BM_ValidIdentifiers<1, 64, false>              9.71ms ± 2%  9.74ms ± 1%     ~     (p=1.000 n=5+5)
BM_ValidIdentifiers<1, 1, true>                3.17ms ± 1%  3.22ms ± 2%     ~     (p=0.151 n=5+5)
BM_ValidIdentifiers<3, 5, true>                11.5ms ± 2%  11.6ms ± 3%     ~     (p=0.548 n=5+5)
BM_ValidIdentifiers<3, 16, true>               11.3ms ± 3%  11.6ms ± 3%     ~     (p=0.095 n=5+5)
BM_ValidIdentifiers<12, 64, true>              12.8ms ± 1%  12.8ms ± 1%     ~     (p=1.000 n=5+5)
BM_HorizontalWhitespace/1                      11.6ms ± 1%  11.7ms ± 2%     ~     (p=0.310 n=5+5)
BM_HorizontalWhitespace/4                      12.9ms ± 1%  11.8ms ± 0%   -8.50%  (p=0.008 n=5+5)
BM_HorizontalWhitespace/16                     17.3ms ± 4%  12.5ms ± 1%  -27.69%  (p=0.008 n=5+5)
BM_HorizontalWhitespace/64                     28.9ms ± 3%  16.0ms ± 2%  -44.88%  (p=0.008 n=5+5)
BM_HorizontalWhitespace/128                    47.6ms ± 3%  21.0ms ± 0%  -55.88%  (p=0.016 n=5+4)
BM_RandomSource                                7.92ms ± 1%  7.70ms ± 3%   -2.74%  (p=0.016 n=5+5)
BM_GroupingSymbols/1/0/0                       5.92ms ± 2%  5.86ms ± 1%     ~     (p=0.310 n=5+5)
BM_GroupingSymbols/2/0/0                       5.30ms ± 1%  5.01ms ± 1%   -5.52%  (p=0.008 n=5+5)
BM_GroupingSymbols/3/0/0                       4.48ms ± 0%  3.95ms ± 1%  -11.69%  (p=0.008 n=5+5)
BM_GroupingSymbols/4/0/0                       4.61ms ± 1%  3.73ms ± 1%  -19.12%  (p=0.008 n=5+5)
BM_GroupingSymbols/8/0/0                       5.34ms ± 6%  3.05ms ± 1%  -42.82%  (p=0.008 n=5+5)
BM_GroupingSymbols/16/0/0                      6.44ms ± 1%  3.20ms ± 2%  -50.24%  (p=0.008 n=5+5)
BM_GroupingSymbols/32/0/0                      10.3ms ± 5%   4.2ms ± 1%  -59.81%  (p=0.008 n=5+5)
BM_GroupingSymbols/0/1/0                       5.17ms ± 2%  5.17ms ± 1%     ~     (p=0.690 n=5+5)
BM_GroupingSymbols/0/2/0                       4.04ms ± 1%  4.04ms ± 2%     ~     (p=1.000 n=5+5)
BM_GroupingSymbols/0/3/0                       2.89ms ± 1%  2.89ms ± 1%     ~     (p=1.000 n=5+5)
BM_GroupingSymbols/0/4/0                       2.54ms ± 1%  2.55ms ± 1%     ~     (p=0.421 n=5+5)
BM_GroupingSymbols/0/8/0                       1.65ms ± 2%  1.67ms ± 1%     ~     (p=0.310 n=5+5)
BM_GroupingSymbols/0/16/0                      1.18ms ± 1%  1.19ms ± 2%     ~     (p=0.222 n=5+5)
BM_GroupingSymbols/0/32/0                       948µs ± 1%   957µs ± 2%     ~     (p=0.310 n=5+5)
BM_GroupingSymbols/0/0/1                       5.17ms ± 1%  5.16ms ± 2%     ~     (p=0.841 n=5+5)
BM_GroupingSymbols/0/0/2                       4.03ms ± 2%  4.04ms ± 2%     ~     (p=0.548 n=5+5)
BM_GroupingSymbols/0/0/3                       2.89ms ± 1%  2.88ms ± 1%     ~     (p=0.841 n=5+5)
BM_GroupingSymbols/0/0/4                       2.54ms ± 1%  2.54ms ± 2%     ~     (p=0.548 n=5+5)
BM_GroupingSymbols/0/0/8                       1.66ms ± 3%  1.67ms ± 2%     ~     (p=0.690 n=5+5)
BM_GroupingSymbols/0/0/16                      1.19ms ± 1%  1.18ms ± 2%     ~     (p=0.548 n=5+5)
BM_GroupingSymbols/0/0/32                       949µs ± 2%   955µs ± 1%     ~     (p=0.310 n=5+5)
BM_GroupingSymbols/32/1/0                      10.0ms ± 1%   4.0ms ± 1%  -59.76%  (p=0.008 n=5+5)
BM_GroupingSymbols/32/2/0                      9.73ms ± 2%  3.92ms ± 2%  -59.73%  (p=0.008 n=5+5)
BM_GroupingSymbols/32/3/0                      9.40ms ± 2%  3.84ms ± 3%  -59.10%  (p=0.008 n=5+5)
BM_GroupingSymbols/32/4/0                      9.20ms ± 2%  3.74ms ± 1%  -59.35%  (p=0.008 n=5+5)
BM_GroupingSymbols/32/8/0                      8.38ms ± 2%  3.50ms ± 1%  -58.22%  (p=0.008 n=5+5)
BM_GroupingSymbols/32/16/0                     7.18ms ± 2%  3.06ms ± 3%  -57.41%  (p=0.008 n=5+5)
BM_GroupingSymbols/32/32/0                     5.53ms ± 1%  2.44ms ± 2%  -55.99%  (p=0.008 n=5+5)
BM_GroupingSymbols/32/32/1                     5.47ms ± 2%  2.40ms ± 2%  -56.08%  (p=0.008 n=5+5)
BM_GroupingSymbols/32/32/2                     5.41ms ± 3%  2.40ms ± 2%  -55.66%  (p=0.008 n=5+5)
BM_GroupingSymbols/32/32/3                     5.28ms ± 2%  2.37ms ± 2%  -55.18%  (p=0.008 n=5+5)
BM_GroupingSymbols/32/32/4                     5.25ms ± 2%  2.34ms ± 2%  -55.52%  (p=0.008 n=5+5)
BM_GroupingSymbols/32/32/8                     5.03ms ± 3%  2.25ms ± 1%  -55.29%  (p=0.008 n=5+5)
BM_GroupingSymbols/32/32/16                    4.62ms ± 1%  2.15ms ± 3%  -53.41%  (p=0.008 n=5+5)
BM_GroupingSymbols/32/32/32                    3.99ms ± 1%  1.86ms ± 1%  -53.24%  (p=0.008 n=5+5)
BM_BlankLines/1                                12.8ms ± 1%  12.6ms ± 2%     ~     (p=0.310 n=5+5)
BM_BlankLines/4                                16.0ms ± 3%  15.8ms ± 1%     ~     (p=0.310 n=5+5)
BM_BlankLines/16                               33.1ms ± 2%  32.1ms ± 1%   -3.29%  (p=0.008 n=5+5)
BM_BlankLines/64                               84.6ms ± 3%  84.2ms ± 3%     ~     (p=0.690 n=5+5)
BM_BlankLines/128                               159ms ± 4%   155ms ± 3%     ~     (p=0.310 n=5+5)
BM_CommentLines/1/0/0                          14.5ms ± 2%  14.5ms ± 2%     ~     (p=0.690 n=5+5)
BM_CommentLines/4/0/0                          19.0ms ± 1%  19.0ms ± 1%     ~     (p=0.548 n=5+5)
BM_CommentLines/128/0/0                         188ms ± 2%   186ms ± 1%     ~     (p=0.151 n=5+5)
BM_CommentLines/1/30/0                         14.8ms ± 3%  14.7ms ± 2%     ~     (p=0.421 n=5+5)
BM_CommentLines/4/30/0                         21.8ms ± 1%  21.3ms ± 4%     ~     (p=0.095 n=5+5)
BM_CommentLines/128/30/0                        201ms ± 1%   200ms ± 2%     ~     (p=0.421 n=5+5)
BM_CommentLines/1/70/0                         15.5ms ± 3%  15.2ms ± 4%     ~     (p=0.095 n=5+5)
BM_CommentLines/4/70/0                         23.2ms ± 1%  22.5ms ± 2%   -2.76%  (p=0.008 n=5+5)
BM_CommentLines/128/70/0                        213ms ± 1%   209ms ± 1%   -1.54%  (p=0.016 n=5+5)
BM_CommentLines/1/0/2                          15.3ms ± 1%  14.5ms ± 1%   -4.99%  (p=0.008 n=5+5)
BM_CommentLines/4/0/2                          21.4ms ± 1%  20.2ms ± 2%   -5.48%  (p=0.008 n=5+5)
BM_CommentLines/128/0/2                         242ms ± 2%   218ms ± 5%  -10.13%  (p=0.008 n=5+5)
BM_CommentLines/1/30/2                         15.7ms ± 4%  15.1ms ± 2%   -3.37%  (p=0.008 n=5+5)
BM_CommentLines/4/30/2                         24.3ms ± 1%  22.5ms ± 3%   -7.42%  (p=0.008 n=5+5)
BM_CommentLines/128/30/2                        268ms ± 2%   240ms ± 3%  -10.22%  (p=0.008 n=5+5)
BM_CommentLines/1/70/2                         16.1ms ± 2%  15.3ms ± 3%   -5.24%  (p=0.008 n=5+5)
BM_CommentLines/4/70/2                         25.7ms ± 3%  24.0ms ± 3%   -6.69%  (p=0.008 n=5+5)
BM_CommentLines/128/70/2                        272ms ± 1%   247ms ± 1%   -9.21%  (p=0.008 n=5+5)
BM_CommentLines/1/0/8                          17.2ms ± 5%  14.8ms ± 2%  -14.32%  (p=0.008 n=5+5)
BM_CommentLines/4/0/8                          30.4ms ± 2%  20.8ms ± 2%  -31.47%  (p=0.008 n=5+5)
BM_CommentLines/128/0/8                         463ms ± 1%   260ms ± 1%  -43.89%  (p=0.008 n=5+5)
BM_CommentLines/1/30/8                         17.2ms ± 2%  15.2ms ± 2%  -12.01%  (p=0.008 n=5+5)
BM_CommentLines/4/30/8                         32.4ms ± 1%  23.2ms ± 3%  -28.61%  (p=0.008 n=5+5)
BM_CommentLines/128/30/8                        498ms ± 3%   287ms ± 2%  -42.32%  (p=0.008 n=5+5)
BM_CommentLines/1/70/8                         17.6ms ± 2%  15.5ms ± 3%  -11.61%  (p=0.008 n=5+5)
BM_CommentLines/4/70/8                         34.0ms ± 4%  24.7ms ± 3%  -27.31%  (p=0.008 n=5+5)
BM_CommentLines/128/70/8                        497ms ± 2%   297ms ± 4%  -40.29%  (p=0.008 n=5+5)
```

Stacked on top of #3287 -- only the last commit should be reviewed here.
2023-10-13 05:11:04 +00:00
Richard Smith 870ccf3eac Suppress follow-on errors for various forms of expression. (#3292)
Don't produce an error diagnostic if any of the information leading to
identifying that error is itself known to be affected by an
already-diagnosed error.
2023-10-13 05:01:03 +00:00
Chandler Carruth a79ea4b28d Do more precise table dispatch for symbols. (#3287)
When originally switching to the table dispatch approach we discussed
that it'd be nice to disentangle the monolithic symbol lexing routine
with this as we'll typically have fairly precise dispatch. This is
especially true for grouping symbols, which in Carbon are all
constructively one-character (at this point).

I think this provides a substantial improvement to the clarity of the
code by disentangling the different paths. It also allowed a bunch of
simplifications / clarifications to exactly what the behavior with
closing invalid groups actually involves currently.

This was initially motivated by code organization improvements, and any
performance wins were speculative. However, when benchmarking it
surfaced a problem that hadn't been clear -- we're generating too many
distinct functions here, and the table-based dispatch slows down in the
face of that.

So this PR also includes a fix for that, removing the template-generated
fan-out of dispatch functions for distinct symbols. Instead, we have
a dedicated table to translate one character into the token kinds. This
seems to work quite well, avoiding the huge branch-y structure and just
do fairly cheap table translation & dispatch for all one-character
symbols. Building the table requires the token kinds to be default
constructable, so this also enables that and arranges for the zero-value
kind to be the error kind.

Combined, this is a modest speedup for *non* grouping symbols (3-4%,
a bit noisy). And in some cases it is a huge speedup for grouping
symbols (>10%).

Raw benchmark data with 20 runs before/after -- despite the # of runs,
the grouping symbols benchmarks were frustratingly noisy in non-uniform
ways that couldn't fully be accounted for here. Still, this seems like
an overall improvement.

```
BM_RandomSource               7.98ms ± 2%  7.73ms ± 3%   -3.12%  (p=0.000 n=18+19)
BM_GroupingSymbols/1/0/0      5.90ms ± 2%  5.82ms ± 4%   -1.38%  (p=0.001 n=20+20)
BM_GroupingSymbols/2/0/0      5.21ms ± 2%  5.15ms ± 2%   -1.14%  (p=0.002 n=20+18)
BM_GroupingSymbols/3/0/0      4.42ms ± 2%  4.34ms ± 2%   -1.87%  (p=0.000 n=19+18)
BM_GroupingSymbols/4/0/0      4.29ms ± 2%  4.38ms ± 5%     ~     (p=0.297 n=17+20)
BM_GroupingSymbols/8/0/0      5.09ms ±10%  5.10ms ± 7%     ~     (p=0.919 n=18+20)
BM_GroupingSymbols/16/0/0     6.35ms ± 8%  6.29ms ± 6%     ~     (p=0.201 n=20+20)
BM_GroupingSymbols/32/0/0     9.88ms ± 2%  9.83ms ± 1%     ~     (p=0.167 n=18+20)
BM_GroupingSymbols/0/1/0      5.12ms ± 2%  5.01ms ± 2%   -2.14%  (p=0.000 n=20+19)
BM_GroupingSymbols/0/2/0      4.01ms ± 2%  3.93ms ± 4%   -2.03%  (p=0.000 n=20+19)
BM_GroupingSymbols/0/3/0      2.92ms ± 3%  2.81ms ± 2%   -3.87%  (p=0.000 n=20+19)
BM_GroupingSymbols/0/4/0      2.61ms ± 3%  2.47ms ± 2%   -5.30%  (p=0.000 n=20+18)
BM_GroupingSymbols/0/8/0      1.77ms ± 3%  1.61ms ± 2%   -8.91%  (p=0.000 n=18+19)
BM_GroupingSymbols/0/16/0     1.41ms ± 3%  1.16ms ± 4%  -17.66%  (p=0.000 n=20+20)
BM_GroupingSymbols/0/32/0     1.10ms ± 2%  0.92ms ± 3%  -16.36%  (p=0.000 n=20+17)
BM_GroupingSymbols/0/0/1      5.09ms ± 2%  5.03ms ± 3%   -1.11%  (p=0.001 n=20+18)
BM_GroupingSymbols/0/0/2      4.01ms ± 2%  3.91ms ± 2%   -2.67%  (p=0.000 n=20+18)
BM_GroupingSymbols/0/0/3      2.93ms ± 3%  2.81ms ± 2%   -4.23%  (p=0.000 n=20+19)
BM_GroupingSymbols/0/0/4      2.59ms ± 2%  2.48ms ± 3%   -4.48%  (p=0.000 n=20+19)
BM_GroupingSymbols/0/0/8      1.75ms ± 1%  1.62ms ± 3%   -7.65%  (p=0.000 n=17+19)
BM_GroupingSymbols/0/0/16     1.40ms ± 2%  1.15ms ± 3%  -17.67%  (p=0.000 n=19+20)
BM_GroupingSymbols/0/0/32     1.10ms ± 2%  0.92ms ± 3%  -15.91%  (p=0.000 n=20+19)
BM_GroupingSymbols/32/1/0     9.62ms ± 2%  9.65ms ± 2%     ~     (p=0.654 n=18+20)
BM_GroupingSymbols/32/2/0     9.41ms ± 2%  9.37ms ± 2%     ~     (p=0.095 n=20+19)
BM_GroupingSymbols/32/3/0     9.13ms ± 2%  9.13ms ± 3%     ~     (p=0.687 n=19+20)
BM_GroupingSymbols/32/4/0     8.93ms ± 1%  8.87ms ± 2%   -0.69%  (p=0.010 n=20+18)
BM_GroupingSymbols/32/8/0     8.15ms ± 2%  8.14ms ± 3%     ~     (p=0.729 n=19+19)
BM_GroupingSymbols/32/16/0    7.04ms ± 3%  6.92ms ± 1%   -1.71%  (p=0.000 n=20+18)
BM_GroupingSymbols/32/32/0    5.48ms ± 2%  5.38ms ± 3%   -1.81%  (p=0.000 n=20+20)
BM_GroupingSymbols/32/32/1    5.39ms ± 2%  5.29ms ± 2%   -1.87%  (p=0.000 n=19+19)
BM_GroupingSymbols/32/32/2    5.34ms ± 2%  5.21ms ± 1%   -2.45%  (p=0.000 n=20+18)
BM_GroupingSymbols/32/32/3    5.27ms ± 3%  5.16ms ± 2%   -2.18%  (p=0.000 n=20+19)
BM_GroupingSymbols/32/32/4    5.21ms ± 2%  5.10ms ± 3%   -2.11%  (p=0.000 n=19+20)
BM_GroupingSymbols/32/32/8    4.98ms ± 2%  4.83ms ± 2%   -2.85%  (p=0.000 n=19+19)
BM_GroupingSymbols/32/32/16   4.55ms ± 2%  4.45ms ± 2%   -2.25%  (p=0.000 n=18+20)
BM_GroupingSymbols/32/32/32   3.95ms ± 2%  3.84ms ± 2%   -2.98%  (p=0.000 n=19+20)
```
2023-10-13 03:58:25 +00:00
Richard Smith 17e053798c Fix incorrect argc calculation. (#3290)
Fix off-by-one error: the terminating `nullptr` in `argv` is not
included in `argc`. This is currently causing crashing tests to crash
again in their crash handler, meaning we don't get a backtrace or
CHECK-failure message.
2023-10-12 21:20:37 +00:00
Chandler Carruth 9ce9572522 Add a benchmark to stress test grouping symbols. (#3286)
This isn't really representative of anything, but it should help make it
obvious when the handling of grouping symbols improves or regresses.
Notably, the random source microbenchmark has *no* grouping symbols (in
order to let it be random but always lexically valid), and so it's
especially useful to have something that checks grouping symbols given
their prevalence in realistic source code.
2023-10-12 21:16:04 +00:00
josh11bandRichard Smith 8d0831f431 Made function and namespace nodes typed to remove a crash (#3285)
Bug found by fuzzing. Problem was untyped SemIR nodes had an invalid
type id, which was retrieved by `HandlePrefixOperator` and then passed
to `context.GetUnqualifiedType`, ultimately performing an invalid access
in `semantics_ir_->GetNode`.

We prefer to make a placeholder type for functions and namespaces to
remove the need for checking for the untyped case everywhere. Eventually
functions will have their own types, but this approach will be needed
for namespaces (and perhaps other non-first-class entities like unbound
methods and interface members) long term.

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2023-10-12 21:14:16 +00:00
6ba8712fbd Predetermine all the line splits in the lexer. (#3278)
## Summary ##

Restructures the lexer to first scan the entire source text for newlines
and create all the line structures needed. Doing this up-front makes it
easy to produce an optimized version with minimal complexity. Currently,
it leverages the system `memchr`, but even when expanded to handle more
complex cases like CR+LF line endings, being isolated in this way will
result in a significantly simpler implementation. This change improves
the lexing of comment lines significantly by skipping their contents
immediately. The overhead of the pre-scan is unmeasurable in all
realistic benchmarks, and 10-30% in benchmarks consisting almost
entirely of blank lines or comments. The improvement of comment lexing
with average length comment lines mixed with code starts at 20% and goes
up. Regressing blank line handling for non-empty comments seems like the
right tradeoff (by far).

## Background and details ##

One weak point in the lexer implementation were large runs of comments.
While those aren't terribly common, they shouldn't present a hazard to
the lexer performance.

A bit more common is a pattern of comments like the following:

```carbon
  // Some method comment here.
  fn SomeMethodName(...) -> ...;

  // Some other method comment here.
  fn SomeOtherMethodName(...) -> ...;
```

Here, the lexer spends an inordinate amount of time getting from the
`\n` after the first semicolon to the `fn` token. It has to skip a blank
line, scan a line, find the `//` comment start, then scan to find the
next `\n`, and then scan horizontal whitespace, etc.

It is tempting to build a scanner *exactly* for this. In fact, I built
one, and I can publish it in a PR if folks are interested in what it
looks like. For x86-64, the PSHUFB trick used for scanning identifiers
technically works. But it is *complicated*. Amazingly so. 150 lines of
very subtle code with subtle performance pitfalls at ever turn. I felt
very uncomfortable submitting it, but we can always go back to it.
Nothing I've come up with quite matches it for sheer speed.

However, most of the complexity and time is spent walking from a `//` to
the end of the line. And *that* is something we can do very simply. In
fact, there is a tuned function for that in libc: `memchr`. Using this
we can build a very fast and much simpler scanner to split lines
up-front. This PR uses that and a carefully crafted fast loop to first
build up all the line info we need. Getting this to be as fast as
possible required some other subtle changes, for example always creating
a line structure that goes from the last `\n` and the end of the file.
We then back up the EOF token to avoid surfacing this to users. The nice
thing is the EOF token isn't part of any hot loop, and so this removes
branches everywhere else at modest complexity.

Once we have that, the rest of the lexer just needs to keep track of its
current line in order to record column offsets. I've taken some care to
try and optimize the lexer's usage of the line structures but there are
more opportunities here I suspect.

Combined, this gets much but not all of the performance of a huge SIMD
scanner for newline-through-to-next-token. For extreme cases (100s of
blank lines or empty comment lines between tokens) the holistic scanner
is of course still much faster, but those don't seem nearly worth the
cost.

I was initially worried about the overhead of taking two passes over the
source text, but in practice I've not been able to measure any
appreciable cost to this with realistic source files. In some cases
benchmarks with no newlines get *faster* because we use a much more
efficient approach to fetch the source text into cache as
a happenstance. And that in turn makes the byte-wise dispatched loop run
faster as it stalls less.

I'm particularly happy with this approach because it seems very clear
how to extend this to support CR+LF, bare CR, and even complex mixtures
without any significant speed cost. That wasn't at all true for the
other approaches explored.

I may try some further PRs to smooth out the last bits of slowness here,
but already this is working excellent for me in practice. My 10mloc test
case is down to 2.3s to lex.

## Raw benchmark data

Using a tool that runs benchmarks before and after and analyzes the
results, the following summarizes the CPU-time impact, each of these for
lexing 100k tokens:

```
BM_ValidKeywords                               2.57ms ± 1%  2.58ms ± 0%     ~     (p=0.190 n=5+4)
BM_ValidIdentifiers<1, 64, false>              9.24ms ± 4%  9.31ms ± 4%     ~     (p=0.421 n=5+5)
BM_ValidIdentifiers<1, 1, true>                3.05ms ± 4%  3.11ms ± 4%     ~     (p=0.222 n=5+5)
BM_ValidIdentifiers<3, 5, true>                10.9ms ± 0%  11.1ms ± 1%   +1.76%  (p=0.016 n=4+5)
BM_ValidIdentifiers<3, 16, true>               11.1ms ± 7%  11.0ms ± 1%     ~     (p=0.310 n=5+5)
BM_ValidIdentifiers<12, 64, true>              12.2ms ± 1%  12.3ms ± 2%     ~     (p=0.111 n=4+5)
BM_HorizontalWhitespace/1                      11.2ms ± 6%  11.1ms ± 2%     ~     (p=0.841 n=5+5)
BM_HorizontalWhitespace/4                      12.0ms ± 3%  12.0ms ± 2%     ~     (p=0.548 n=5+5)
BM_HorizontalWhitespace/16                     16.2ms ± 6%  15.9ms ± 8%     ~     (p=0.690 n=5+5)
BM_HorizontalWhitespace/64                     27.7ms ± 3%  28.4ms ± 3%     ~     (p=0.151 n=5+5)
BM_HorizontalWhitespace/128                    44.3ms ± 1%  45.6ms ± 6%   +3.15%  (p=0.032 n=5+5)
BM_RandomSource                                7.75ms ± 2%  7.72ms ± 1%     ~     (p=1.000 n=5+5)
BM_BlankLines/1                                11.7ms ± 1%  12.1ms ± 1%   +3.46%  (p=0.008 n=5+5)
BM_BlankLines/4                                14.0ms ± 2%  15.2ms ± 3%   +8.12%  (p=0.008 n=5+5)
BM_BlankLines/16                               23.5ms ± 2%  31.1ms ± 4%  +32.26%  (p=0.008 n=5+5)
BM_BlankLines/64                               75.3ms ± 1%  81.2ms ± 3%   +7.83%  (p=0.008 n=5+5)
BM_BlankLines/128                               133ms ± 3%   150ms ± 2%  +12.74%  (p=0.008 n=5+5)
BM_CommentLines/1/0/0                          13.1ms ± 0%  13.7ms ± 1%   +5.11%  (p=0.008 n=5+5)
BM_CommentLines/4/0/0                          16.6ms ± 1%  18.2ms ± 4%   +9.56%  (p=0.008 n=5+5)
BM_CommentLines/128/0/0                         169ms ± 4%   182ms ± 1%   +7.24%  (p=0.008 n=5+5)
BM_CommentLines/1/30/0                         18.7ms ± 5%  14.1ms ± 0%  -24.84%  (p=0.008 n=5+5)
BM_CommentLines/4/30/0                         36.5ms ± 6%  20.6ms ± 3%  -43.59%  (p=0.008 n=5+5)
BM_CommentLines/128/30/0                        525ms ± 4%   198ms ± 1%  -62.38%  (p=0.008 n=5+5)
BM_CommentLines/1/70/0                         23.4ms ± 6%  14.7ms ± 2%  -37.15%  (p=0.008 n=5+5)
BM_CommentLines/4/70/0                         53.3ms ± 7%  22.4ms ± 4%  -57.99%  (p=0.008 n=5+5)
BM_CommentLines/128/70/0                        1.05s ± 4%   0.21s ± 2%  -80.31%  (p=0.008 n=5+5)
BM_CommentLines/1/0/2                          14.1ms ± 6%  14.3ms ± 1%     ~     (p=0.151 n=5+5)
BM_CommentLines/4/0/2                          19.4ms ± 5%  20.1ms ± 1%     ~     (p=0.151 n=5+5)
BM_CommentLines/128/0/2                         238ms ± 8%   229ms ± 0%     ~     (p=0.151 n=5+5)
BM_CommentLines/1/30/2                         19.2ms ± 7%  14.6ms ± 1%  -23.87%  (p=0.008 n=5+5)
BM_CommentLines/4/30/2                         40.3ms ±13%  22.3ms ± 4%  -44.63%  (p=0.008 n=5+5)
BM_CommentLines/128/30/2                        568ms ± 7%   254ms ± 3%  -55.28%  (p=0.008 n=5+5)
BM_CommentLines/1/70/2                         23.3ms ± 1%  15.0ms ± 3%  -35.61%  (p=0.016 n=4+5)
BM_CommentLines/4/70/2                         57.2ms ± 9%  24.1ms ± 2%  -57.81%  (p=0.008 n=5+5)
BM_CommentLines/128/70/2                        1.07s ± 0%   0.26s ± 2%  -75.51%  (p=0.016 n=4+5)
BM_CommentLines/1/0/8                          15.9ms ± 7%  16.0ms ± 1%     ~     (p=0.151 n=5+5)
BM_CommentLines/4/0/8                          24.2ms ± 6%  27.9ms ± 2%  +15.36%  (p=0.008 n=5+5)
BM_CommentLines/128/0/8                         386ms ± 4%   445ms ± 1%  +15.28%  (p=0.008 n=5+5)
BM_CommentLines/1/30/8                         20.6ms ± 5%  16.3ms ± 1%  -20.95%  (p=0.008 n=5+5)
BM_CommentLines/4/30/8                         45.3ms ± 6%  30.3ms ± 3%  -32.98%  (p=0.008 n=5+5)
BM_CommentLines/128/30/8                        699ms ± 3%   477ms ± 3%  -31.83%  (p=0.008 n=5+5)
BM_CommentLines/1/70/8                         25.7ms ± 5%  16.8ms ± 2%  -34.67%  (p=0.008 n=5+5)
BM_CommentLines/4/70/8                         62.0ms ± 4%  31.6ms ± 2%  -49.10%  (p=0.008 n=5+5)
BM_CommentLines/128/70/8                        1.20s ± 2%   0.48s ± 4%  -59.60%  (p=0.008 n=5+5)
```

The horizontal whitespace benchmark (and all of the non-line-oriented
ones) are noisier than they appear here but do show some improvements
(surprisingly). My guess is that it has a lot to do with system load, as
the advantage is that we're using a vectorized loop to scan the text
first and then doing the byte-dispatched loop. So when the cache is
a bit slower to populate, the vectorized version starts to be faster.

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: josh11b <josh11b@users.noreply.github.com>
2023-10-12 07:13:44 +00:00
5041a14f59 Add whitespace- and comment-specific benchmarking. (#3276)
These benchmarks zero-in and stress test horizontal and vertical
whitespace as well as comment lexing performance. They set up
essentially a worst-case scenario of ramping up whitespace between very
sparse tokens to show how the lexer copes with this.

The horizontal whitespace benchmark is perhaps less important as
frequent runs of 50-characters of horizontal whitespace are relatively
rare already, and likely to be exceedingly rare without trailing
comments. But its good to include for completeness and it shows
reasonably strong performance with the current table-dispatch approach.

The blank line and comment line benchmarks are much more important. Lots
of code is relatively line-sparse, especially API files that are perhaps
the most useful to parse quickly. And many of these are a mixture of
sparse with blank lines and sparse with large comment blocks. The
benchmarks show that there are some serious limits here, even falling
below 100k tokens per second throughput on some of the stress tests
here.

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: josh11b <josh11b@users.noreply.github.com>
2023-10-12 06:54:52 +00:00
Chandler CarruthandRichard Smith 2d735bbc51 Enhance the main lexer benchmark. (#3275)
This generalizes the main lexer benchmark's source generation to be
a bit more comprehensive, specifically including whitespace and
comments. Without these, we're missing a key part of the lexer's
performance.

This also tidies up a bit of the code and adds a more specific
distribution of the different factors in lexing based on analysis of
LLVM's source code. The enhancements to the source statistics script
that helped collect the data here will be in a separate PR.

With this, the output on my AMD cloud instance is:
```
-------------------------------------------------------------------------------------------------------------------------
Benchmark                                            Time             CPU   Iterations bytes_per_second tokens_per_second
-------------------------------------------------------------------------------------------------------------------------
BM_ValidKeywords                               2809011 ns      2808912 ns          243       212.616M/s         35.601M/s
BM_ValidIdentifiers<1, 64, false>             11461783 ns     11461652 ns           61       128.499M/s        8.72475M/s
BM_ValidIdentifiers<1, 1, true>                3397293 ns      3397240 ns          208       84.2158M/s        29.4357M/s
BM_ValidIdentifiers<3, 5, true>               14165143 ns     14164962 ns           51       40.3956M/s        7.05967M/s
BM_ValidIdentifiers<3, 16, true>              15283128 ns     15282583 ns           47       71.7623M/s         6.5434M/s
BM_ValidIdentifiers<12, 64, true>             17417323 ns     17417109 ns           41       219.007M/s        5.74148M/s
------------------------------------------------------------------------------------------------------------------------------------------
Benchmark                                            Time             CPU   Iterations bytes_per_second lines_per_second tokens_per_second
------------------------------------------------------------------------------------------------------------------------------------------
BM_RandomSource                                8132211 ns      8132227 ns           84       137.223M/s        3.9036M/s        12.2968M/s
BM_SpeedOfLightStrCpy                            29610 ns        29608 ns        24631       36.8065G/s       1072.17M/s        3.37745G/s
BM_SpeedOfLightDispatch<1>                     2144418 ns      2144421 ns          327       520.387M/s       14.8035M/s        46.6326M/s
BM_SpeedOfLightDispatch<2>                     1945954 ns      1945827 ns          351       573.498M/s       16.3144M/s         51.392M/s
BM_SpeedOfLightDispatch<4>                     2519565 ns      2519467 ns          292       442.923M/s       12.5999M/s        39.6909M/s
BM_SpeedOfLightDispatch<8>                     3011965 ns      3011968 ns          238       370.498M/s       10.5396M/s        33.2009M/s
BM_SpeedOfLightDispatch<16>                    4379575 ns      4379579 ns          160       254.803M/s       7.24841M/s        22.8332M/s
BM_SpeedOfLightDispatch<32>                    6678423 ns      6678353 ns          102       167.096M/s       4.75342M/s        14.9738M/s
BM_SpeedOfLightDispatch<MaxDispatchTargets>    9373075 ns      9372688 ns           75       119.062M/s       3.38697M/s        10.6693M/s
```

I've compared the profile of the `BM_RandomSource` benchmark with this
change and it largely corresponds to what I expect based on profiling
hand-crafted Carbon inputs. And as you can see, we're closing in on
lexing at least hitting the 10-million-lines-per-second mark. =]

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2023-10-12 06:35:24 +00:00
Richard Smithandjosh11b 9c3e25decf Add SemIR::Node::Is<TypedNode>(). (#3284)
This allows node kind checks to be written a little more concisely.

---------

Co-authored-by: josh11b <josh11b@users.noreply.github.com>
2023-10-12 00:38:41 +00:00
Richard Smith 8779fcd77c Switch from SemIR::NodeKind::Foo to SemIR::Foo::Kind wherever possible. (#3283)
This is shorter, more closely connected to code using the typed node
types, and avoids using the ambiguous word `Node` in places referring to
typed `SemIR` nodes.
2023-10-12 00:16:08 +00:00
Richard Smith 6e9d83e746 Support for while statements. (#3258)
Basic support for type-checking and lowering of `while` statements, as
well as `break` and `continue`.
2023-10-11 19:20:46 +00:00
Richard Smith c7a9e29a89 Add typed nodes to SemIR. (#3280)
Replace `SemIR::Node::GetAsFoo` and `SemIR::Node::Foo::Make` with
`SemIR::Foo` class that represents a particular kind of node, with named
fields.

Rename `SemIR::IntegerLiteral` and `SemIR::RealLiteral` to
`IntegerValue` / `RealValue` to better reflect their purpose and avoid a
name collision with the corresponding `SemIR` node kinds.

Remove `NodeKind::Invalid` and the `SemIR::Node` default constructor
entirely, as they were not used for anything.
2023-10-11 05:39:59 +00:00
Chandler Carruth 0e8e94d8bf Expand source stats to roughly cover more tokens. (#3277)
This is pretty rough both in code-quality and what it tries to cover.
The coverage approximation is probably fine as it mostly just gives some
vague idea of the distributions we should aim at when evaluating
performance. We still want performance with unusual distributions to be
good.

Happy to improve the code quality if folks want, and especially with
suggestions on what would help. For this kind of quick scripting, it
seemed "fine" to me.
2023-10-11 00:50:00 +00:00
Chandler Carruth 6f5934a505 Unblock more lexer inlining. (#3274)
The big change is to make the lexer helpers have internal linkage,
making all of them easy to inline into single call sites.

Looking at the profile showed several other cases of unfortunate
out-of-line functions. Two were due to the code size produced for checks
-- those are switched to `DCHECK`s to remove that code from optimized
builds. The loss of coverage seems minor.

A last one was closing open groups. This was a surprising routine to be
hot, but it the paths to discover "nothing to do here" were intertwined
into the code. This PR extracts this common trace into a separate
function that delegates to the looping recovery path. This lets the hot
path inline easily.

At this point, for a large lexing benchmark I'm using, 50% of the time
is in the identifier hash table at this point. The remaining
improvements are to actually make some of the hot routines like symbol
lexing and comment lexing faster.
2023-10-10 21:30:07 +00:00
Chandler Carruth d1e3749aa8 Workaround issues with sanitizers on macOS. (#3279)
The latest versions of Clang, at least on an ARM mac, enforce that we
not use static sanitizer runtimes. The flag is also a bit frustrating:
it has to be split out of other flags in order to remove it, you can't
just disable it or ignore a warning about it being unused.

This gets things to be build and run again. However, the runtimes (I'm
guessing ones that ship with the OS?) its using dynamically don't
actually work -- at least one check was hitting pretty obvious false
positives. So I've added a set of sanitizer flag workarounds we can
expand as needed to continue to work around the limitations of
sanitizers on this platform.

Together, this restores fastbuild on my ARM macOS with the latest Clang
installed.
2023-10-10 00:41:34 +00:00
Chandler Carruth 03c3b86758 Switch lexer to fully table-driven design. (#3273)
This uses the musttail dispatched table approach to drive the entire
lexing. The result is that there is no main lexer loop at all in a
traditional sense, now everything is driven through tail recursive
dispatch on the next byte of the source text.

This should be easy to extend still -- the design pattern is to add
lexer methods for handling specific cases, and then add a dispatch
function to dispatch to them from the table. For example, we can add a
method that handles decoding UTF-8 outside of the ASCII subset and set
the table entries used by non-ASCII initial bytes to dispatch to it.

The performance is already surprisingly good, benchmarks show a modest
improvement across the board. That's despite there still being some
*serious* performance issues that I'll fix in a separate patch. There
are also opportunities to leverage this structure more heavily as needed
by putting more specialized dispatch targets in for specific bytes.

A follow-up PR will re-organize the functions here, as almost all of the
methods on the `Lexer` should become private, but I wanted to keep that
a separate change since it will probably render the diff even more hard
to read than it already is.
2023-10-07 03:35:24 +00:00
Hana Dusíková 48d40aa0f0 Remove unnecessory constexpr for lambdas in tests. (#3272)
After reading Chandler's code I asked him why he has these. Lambdas will
implicitly constexpr anyway.
2023-10-06 07:25:54 +00:00
Richard Smith 74d52738ff Support for let declarations. (#3257)
A `let` declaration is represented by a `bind_name` node in SemIR:

```carbon-semir
  %b: i32 = bind_name "b", %a
```

Because `Check` encounters the pattern before it sees the value, we
first create the `bind_name` node with an unset value and don't add it
to the block. Then, once we've seen and converted the initializer, we
update the `bind_name` to have the value and add it to the current
block, after the initializer code.
2023-10-06 00:06:21 +00:00
Chandler Carruth c7e6238fa8 Introduce two speed-of-light benchmarks. (#3270)
The goal of these kinds of benchmarks is to help calibrate other
benchmarks and expectations. They benchmark the underlying hardware
capabilities that we can't avoid, and help illustrate bounds for what is
possible. The term "speed-of-light benchmark" references the aspect of
measuring how fast thing could possible run.

The first is a simple memory bandwidth measurement in the best case
scenario -- using `strcpy` over the buffer. This still does a minimal
number of writes to memory and examines each byte of input to see if it
is null, but can cheat in every way possible to run at the maximum speed
of hardware. To a certain extent, we never expect to get close to this
speed, but it's a good illustration of how much headroom the hardware
has available.

The second is potentially more interesting. This illustrates how fast a
byte-by-byte dispatch loop can potentially be. It uses the technique
that I'm hoping to use in the lexer itself of guaranteed tail recursion
to achieve this with a very small code footprint. The performance of
this technique, even when running in this extremely minimal setting to
establish bounds, is hugely dependent on the number of distinct dispatch
targets, and so the benchmark includes a healthy range to show the range
of performance that we might expect when running in a byte-by-byte mode.
Note that we should expect the lexer to be *faster* than this
"speed-of-light" whenever it is able to lex in larger granules than
byte-wise. But for complex, dense token sequences that force looking at
every byte, this shows the "worst case" "speed-of-light" in a sense.

On my recent AMD cloud VM instance, I get the following results running
the main lexer benchmark with these changes included:

```
-------------------------------------------------------------------------------------------------------------------------
Benchmark                                            Time             CPU   Iterations bytes_per_second tokens_per_second
-------------------------------------------------------------------------------------------------------------------------
BM_ValidKeywords                               3169403 ns      3169283 ns          221        188.44M/s        31.5529M/s
BM_ValidIdentifiers<1, 64, false>             12486725 ns     12486445 ns           51       117.953M/s        8.00868M/s
BM_ValidIdentifiers<1, 1, true>                3950455 ns      3950298 ns          178       72.4252M/s        25.3145M/s
BM_ValidIdentifiers<3, 5, true>               15562294 ns     15561178 ns           45       36.7712M/s        6.42625M/s
BM_ValidIdentifiers<3, 16, true>              16118656 ns     16118374 ns           44       68.0412M/s         6.2041M/s
BM_ValidIdentifiers<12, 64, true>             19116271 ns     19116258 ns           35       199.541M/s        5.23115M/s
BM_ValidMix/10/40                              7074336 ns      7073795 ns           93       140.744M/s        14.1367M/s
BM_ValidMix/25/30                              6790722 ns      6790006 ns          102       131.793M/s        14.7275M/s
BM_ValidMix/50/20                              5960514 ns      5960443 ns          118       112.594M/s        16.7773M/s
BM_ValidMix/75/10                              4325546 ns      4325556 ns          159       102.559M/s        23.1184M/s
BM_SpeedOfLightStrCpy                            24339 ns        24339 ns        29650       35.9049G/s        4.10858G/s
BM_SpeedOfLightDispatch<1>                     1756051 ns      1755800 ns          398       509.668M/s        56.9541M/s
BM_SpeedOfLightDispatch<2>                     1611973 ns      1611725 ns          436       555.228M/s        62.0453M/s
BM_SpeedOfLightDispatch<4>                     2064280 ns      2063990 ns          326       433.565M/s        48.4498M/s
BM_SpeedOfLightDispatch<8>                     2484055 ns      2483946 ns          280       360.263M/s        40.2585M/s
BM_SpeedOfLightDispatch<16>                    4550963 ns      4550894 ns          155       196.637M/s        21.9737M/s
BM_SpeedOfLightDispatch<32>                    6507077 ns      6507090 ns          107       137.523M/s        15.3679M/s
BM_SpeedOfLightDispatch<MaxDispatchTargets>    9071198 ns      9071217 ns           77       98.6499M/s        11.0239M/s
```

Even though we're not lexing anything in the speed-of-light benchmark,
the tokens-per-second measure is still meaningful because we *generated*
the token stream and know how many tokens we put into it. The dispatch
technique easily exceeds hits 10-million tokens/second, but we need to
do substantially better than that to lex at 10-million lines/second.
Fortunately, when the lexer is consuming more than one-byte tokens,
we're already faster than this. And the bytes-per-second numbers from
all but the worst case dispatch scenario are promising.
2023-10-06 00:04:29 +00:00
Richard Smith d306a41453 Allow our test runners to be more easily run outside bazel. (#3269)
Don't assume that the bazel-supplied environment variable TEST_TARGET is
present. We don't actually need it for anything other than providing
feedback to the developer if the test fails.

This makes it a bit easier to reproduce test failures under gdb,
particularly for multi-file tests.
2023-10-05 18:50:41 +00:00
Richard Smith bfa5463e5b Add signature enforcement for Main.Run and give it the symbol name main. (#3266)
For #2550.
2023-10-05 18:24:17 +00:00
Chandler Carruth b8802035ed Switch benchmarks to match unit test namespacing. (#3268)
Specifically, rather than nesting them in `Carbon::Testing`, nest them
in `Carbon::Foo` for whatever component they're benchmarking. All our
current benchmarks are lexer benchmarks so its `Carbon::Lex`.

This makes even more sense for benchmarks than unittests I think.
2023-10-05 17:44:31 +00:00
Chandler Carruth 7dfd7ca3b4 Fix minor UB in the treesitter scanner. (#3267)
In C, the signature `f()` is distinct from `f(void)` -- dating from K&R
style prototype-less functions. We need to use the `f(void)` form for
the scanner creation function so that it can be called by function
pointer `void *(*)(void)` without UB.

This was causing a local test that includes treesitter to fail with our
fastbuild that enables most sanitizers. With this, we may be able to
enable treesitter on our CI as well, but it at least fixes my local test
runs.
2023-10-05 17:36:59 +00:00
Chandler Carruth 4596cd230d Avoid building the non-test file group in :all. (#3191)
This file group exists to allow a `genquery` rule and a Python test to
verify our non-test dependency graph. We don't actually need to build
the binaries in the file group as part of that. The `genquery` rule
seems to do the right thing -- building it directly doesn't cause the
binaries in the group to be built. But without a manual tag, the group
itself is part of `:all` and thus part of `//...` and part of the rules
that will be built even with PR #3106. A consequence is that any change
to the toolchain causes several other binaries to be built as well
because this file group is in the impacted set. Making it manual should
avoid all of this, and without breaking the actual use from `genquery`.

For example, before this change, in a fully cached build after a `bazel
clean`:
```
> bazel test //bazel/check_deps:all
INFO: Invocation ID: 2d83ebee-4c00-425d-be33-23f42b079614
INFO: Analyzed 3 targets (103 packages loaded, 7137 targets configured).
INFO: Found 2 targets and 1 test target...
INFO: Elapsed time: 4.081s, Critical Path: 2.61s
INFO: 3111 processes: 2796 disk cache hit, 315 internal.
INFO: Build completed successfully, 3111 total actions
```

After this change:
```
> bazel test //bazel/check_deps:al
INFO: Invocation ID: c94089e8-a420-4d3c-9902-134e6b55b297
INFO: Analyzed 2 targets (92 packages loaded, 568 targets configured).
INFO: Found 1 target and 1 test target...
INFO: Elapsed time: 0.700s, Critical Path: 0.01s
INFO: 7 processes: 2 disk cache hit, 5 internal.
INFO: Build completed successfully, 7 total actions
```

While here, re-generate the file group, and fix several issues it
uncovers: mark test utilities as `testonly` and update our LLVM package
allowlist to include `clangd`'s package.
2023-10-05 01:30:41 +00:00
Richard Smith 5ccee62918 Add name_reference SemIR node for references to names. (#3260)
Also add `name_reference_untyped` for references to non-first-class
names without types, which currently covers namespaces and functions.

This improves the fidelity of the SemIR representation, and fixes some
issues where we would use the wrong location for nodes and diagnostics
downstream of a name reference.

We're still missing a representation for dotted name expressions, such
as `Namespace.Function`, and we don't use the `untyped` node as an
operand of any other node yet.
2023-10-05 01:15:53 +00:00
Chandler CarruthandRichard Smith d552545c6d Move dispatch routines to be static member functions. (#3265)
These routines have a regular signature and are used to build a table of
function pointers for fast dispatch. However, the previous approach
relied on lambdas to build these functions which resulted in very hard
to read functions in the profile and backtrace.

In preparation for expanding dispatch to handle (many) more cases in the
lexer and also enabling more aggressive inlining into the dispatch
routines, I wanted to tidy up how they appear.

This PR alone shouldn't have any interesting functional effect, it's
just re-organizing the code.

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2023-10-05 00:03:56 +00:00
Richard Smith e15b24e77d Use the name of a function as the name of its file-scope value. (#3262)
As requested in #3260.
2023-10-04 23:50:22 +00:00
Chandler Carruth a46ca6bf7a Add a start-of-file token and parse node. (#3263)
This removes a (very) hot branch in the lexer where we need to special
case when a token is the first token and can't look at its previous
token. It also seems like a generally nice change to the structure of
both the token buffer and parse tree as there are now bracketing
elements for both ends and we should be able to avoid similar branching
in the future.

Mostly mechanical updates to the lexer and parser code to handle this,
but also needed to special case the location information in the
autoupdate code. And then the usual large body of auto-updated tests.

No benchmark data for this change alone as in isolation and in the
current lexer structure it doesn't make a big difference. But this
branch was particularly difficult to handle when trying to update the
whitespace skipping code to be faster, and so I think it is worth
systematically avoiding the special case here.
2023-10-04 23:36:35 +00:00
josh11b 412e4fb461 Update comments in toolchain to point to new names of files (#3264) 2023-10-04 23:05:03 +00:00
Richard Smith 1ac7002bf6 Don't try to infer where to put loads in lowering. (#3146)
Trust semantics to have put them in the right places.

Many parts of lowering still need to be updated to use the value
representation chosen at the semantics layer, but this is an incremental
step towards that.
2023-10-04 19:57:12 +00:00
josh11b 6833652ffa Misc fixes to toolchain (#3261)
Was reading through the code and saw some small improvements.
2023-10-04 00:10:59 +00:00
Richard Smith e469545eec Make autoupdate leave blaze-bin alone and produce less spam. (#3259)
Minor changes to the blaze command line executed by our autoupdate
scripts:

- Don't change the convenience symlinks. Running autoupdate shouldn't
cause `./bazel-bin/...` to switch to running a different binary.
- Don't produce so much spam. Bazel will still log its build progress if
necessary, and still report compile and runtime errors, but won't
produce half a dozen lines of INFO at the start of the command.
2023-10-03 18:56:25 +00:00
josh11bandRichard Smith 88e87b86b9 Updates to generics design details, part 2 (#3253)
Continued from part 1: #3231. Second step updating
`docs/design/generics/details.md`. There remains some work to
incorporate proposal #2200.

- The biggest changes are incorporating much of the text of proposals:
  - #2173
  - #2687
- It incorporates changes from proposals:
  - #989
  - #1178
  - #2138
  - #2200
  - #2360
  - #2964
  - #3162
- It also updates the text to reflect the latest thinking from leads
issues:
  - #996
  - #2153 -- most notably deleting the section on `TypeId`.
- Update to rule for prioritization blocks with mixed type structures
from [discussion on
2023-07-18](https://docs.google.com/document/d/1gnJBTfY81fZYvI_QXjwKk1uQHYBNHGqRLI2BS_cYYNQ/edit?resourcekey=0-ql1Q1WvTcDvhycf8LbA9DQ#heading=h.7jxges9ojgy3)
- Adds reference links to proposals, issues, and discussions relevant to
the text.
- Also tries to use more precise language when talking about
implementations, to avoid confusing `impl` declaration and definitions
with the `impls` operator used in `where` clauses, an issue brought up
in
  - #2495 
  - #2483

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2023-10-03 00:03:07 +00:00
Richard Smith fea6cf88fc Unify initialization and conversion logic (#3255)
Combine the initialization, implicit conversion, and value category
conversion functions into a single function.

This substantially reduces the duplication between these steps, and
ensures that we support the same set of conversions in all these
contexts. This also fixes some issues where we would not use the proper
value representation for tuples and structs after performing implicit
conversions.
2023-10-02 21:53:52 +00:00
Geoff Romer 7899154a21 Add "ERROR" to all error diagnostics (#3251)
This makes the difference between errors and lower-level diagnostics
visible to users, and aligns the toolchain's behavior with the
expectations in `driver_fuzzer.cpp`.
2023-09-26 16:52:49 +00:00
Richard Smith 491fa1bdd5 Place the computation of the destination of an initialization into the return slot. (#3252)
Fix a bug where we would perform the computation of the return location
in SemIR after we have already used it in some cases, leading to
assertion failures during lowering. Instead, accumulate a sequence of
instructions to compute the return location in a temporary block, and
overwrite the return slot with those instructions when we perform
initialization.

StubReference is replaced by a more general SpliceBlock node, that takes
a code block and a result value, executes the instructions in the block,
and produces the result. This is used in the uncommon case where more
than one instruction is required to compute the return slot, which can
happen if we need to first emit a temporary and then index into it, or
if we need to perform multiple levels of indexing before we reach an
entity to initialize.
2023-09-26 01:31:24 +00:00
josh11bandChandler Carruth 58c106010c Updates to design docs to reflect accepted proposals (#3254)
Includes proposals:
- #990
- #2188
- #2138
- #2200
- #2360
- #2760
- #2964
- #3162

Also tries to use more precise language when talking about:
- implementations, to avoid confusing `impl` declaration and definitions
with the `impls` operator used in `where` clauses, an issue brought up
in #2495 and #2483;
- "binding patterns", like `x: i32`, and "bindings" like `x`.

---------

Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2023-09-23 15:53:07 +00:00
Richard Smith caecdc7fdc Refactor finalization of initializers. (#3250)
Factor out the common code to find the return slot for an initializing
expression, and use it to simplify the two different ways we finalize
initializers, as either initializing a temporary or initializing some
specific object.

This slightly changes the SemIR we create for function calls: instead of
rewriting the Call node to have a different destination and replacing
its temporary with a `no_op`, we now replace its temporary with a
`stub_reference` to the new destination. This results in the same amount
of SemIR being produced, but allows calls and other kinds of
initializers to be handled uniformly.
2023-09-21 19:45:23 +00:00
Richard Smith 31d55da403 Stop creating fake integer literals as indexes for tuple initialization. (#3248)
This makes struct and tuple initialization basically identical; unify
them.
2023-09-21 00:41:19 +00:00
Richard Smith f389844893 Remove nearly all uses of StubReferences. (#3249)
The speculative insertion of StubReferences after elements in an
argument list turned out to not be necessary, because we decided we want
to insert per-argument initialization steps after all arguments are
evaluated, rather than interleaving them. The StubReferences we insert
are causing some minor code complexity, so remove them.

We still create StubReferences when performing patch-ups of
already-emitted code, but we no longer ever need to look through them
when determining whether an initializer was a literal or when evaluating
a type expression.
2023-09-21 00:00:36 +00:00