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Switch CARBON_CHECK to a format string API (#4285)

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This switches `DCHECK` and `FATAL` as well.

The goal is to reduce the code size impact of these assertions so that
we can keep more of them enabled. Currently, the largest cost I see from
`CHECK` is not the actual check or the cold code itself, but actually
the failure to inline trivial functions due to the presence of the cold
code. This means that our goal isn't to reduce apparent code size in the
final binary but the LLVM IR cost assessed for these routines in the
inliner, which closely correlates with code size but is a bit different.

As discussed in #4283, experimentation shows that a single function call
with a minimal number of arguments is the lowest cost model for these.
This is easily achieved with a format-string API that internally uses
`llvm::formatv`. This PR is essentially the `CHECK` version of #4283.

However, the check macros are substantially harder to make work with
both format strings and streaming because they also take a condition.
Also, unexpectedly, I was very successful at devising a regular
expression based automated rewrite from the streaming to the format
string form with only low 10s of manual fixes. This includes compacting
strings broken up across lines, etc. Given how well that went, I've
prepared this PR which just directly switches to the format string API
and migrate everything to use it.

One nice side-effect is that the format string approach ends up greatly
simplifying the implementation here as well.

This is ... *shockingly* effective. Parsing speeds up by more than 3%
with just this change. And checking speeds up by **8%** with this change
alone:
```
BM_CompileAPIFileDenseDecls<Phase::Parse>/256      86.3µs ± 1%  82.9µs ± 1%  -3.94%  (p=0.000 n=17+19)
BM_CompileAPIFileDenseDecls<Phase::Parse>/1024      431µs ± 1%   415µs ± 1%  -3.76%  (p=0.000 n=18+19)
BM_CompileAPIFileDenseDecls<Phase::Parse>/4096     1.77ms ± 1%  1.71ms ± 1%  -3.18%  (p=0.000 n=18+19)
BM_CompileAPIFileDenseDecls<Phase::Parse>/16384    7.44ms ± 1%  7.17ms ± 2%  -3.56%  (p=0.000 n=18+20)
BM_CompileAPIFileDenseDecls<Phase::Parse>/65536    30.7ms ± 1%  29.7ms ± 1%  -3.15%  (p=0.000 n=18+20)
BM_CompileAPIFileDenseDecls<Phase::Parse>/262144    131ms ± 1%   127ms ± 1%  -2.81%  (p=0.000 n=18+18)
BM_CompileAPIFileDenseDecls<Phase::Check>/256       878µs ± 2%   800µs ± 1%  -8.91%  (p=0.000 n=19+20)
BM_CompileAPIFileDenseDecls<Phase::Check>/1024     1.88ms ± 2%  1.72ms ± 1%  -8.56%  (p=0.000 n=19+20)
BM_CompileAPIFileDenseDecls<Phase::Check>/4096     5.78ms ± 2%  5.28ms ± 1%  -8.70%  (p=0.000 n=20+18)
BM_CompileAPIFileDenseDecls<Phase::Check>/16384    21.9ms ± 1%  20.1ms ± 1%  -8.02%  (p=0.000 n=18+20)
BM_CompileAPIFileDenseDecls<Phase::Check>/65536    90.4ms ± 2%  83.1ms ± 1%  -8.04%  (p=0.000 n=19+20)
BM_CompileAPIFileDenseDecls<Phase::Check>/262144    381ms ± 2%   352ms ± 1%  -7.79%  (p=0.000 n=19+19)
```

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
This commit is contained in:
Chandler Carruth
2024-09-12 16:42:08 +00:00
committed by GitHub
co-authored by Richard Smith josh11b
parent 35dfa5f03c
commit 4845f40dff
140 changed files with 1234 additions and 1161 deletions
Download Patch File Download Diff File Expand all files Collapse all files
testing/base/source_gen.cpp
+21 -21
View File
@@ -152,10 +152,11 @@ auto SourceGen::ClassGenState::GetValidTypeName() -> llvm::StringRef {
return type_names_.pop_back_val();
}
CARBON_CHECK(last_type_name_index_ != initial_last_type_name_index)
<< "Failed to find a valid type name with " << type_names_.size()
<< " candidates, an initial index of " << initial_last_type_name_index
<< ", and with " << class_names_.size() << " classes left to emit!";
CARBON_CHECK(last_type_name_index_ != initial_last_type_name_index,
"Failed to find a valid type name with {0} candidates, an "
"initial index of {1}, and with {2} classes left to emit!",
type_names_.size(), initial_last_type_name_index,
class_names_.size());
}
}
@@ -319,8 +320,8 @@ auto SourceGen::GenAPIFileDenseDecls(int target_lines,
// needs a blank line.
constexpr int NumFileCommentLines = 4;
double avg_class_lines = EstimateAvgClassDefLines(params.class_params);
CARBON_CHECK(target_lines > NumFileCommentLines + avg_class_lines)
<< "Not enough target lines to generate a single class!";
CARBON_CHECK(target_lines > NumFileCommentLines + avg_class_lines,
"Not enough target lines to generate a single class!");
int num_classes = static_cast<double>(target_lines - NumFileCommentLines) /
(avg_class_lines + 1);
int expected_lines =
@@ -372,9 +373,9 @@ auto SourceGen::GetShuffledIdentifiers(int number, int min_length,
auto SourceGen::GetShuffledUniqueIdentifiers(int number, int min_length,
int max_length, bool uniform)
-> llvm::SmallVector<llvm::StringRef> {
CARBON_CHECK(min_length >= 4)
<< "Cannot trivially guarantee enough distinct, unique identifiers for "
"lengths <= 3";
CARBON_CHECK(min_length >= 4,
"Cannot trivially guarantee enough distinct, unique identifiers "
"for lengths <= 3");
llvm::SmallVector<llvm::StringRef> idents =
GetUniqueIdentifiers(number, min_length, max_length, uniform);
std::shuffle(idents.begin(), idents.end(), rng_);
@@ -398,9 +399,9 @@ auto SourceGen::GetIdentifiers(int number, int min_length, int max_length,
auto SourceGen::GetUniqueIdentifiers(int number, int min_length, int max_length,
bool uniform)
-> llvm::SmallVector<llvm::StringRef> {
CARBON_CHECK(min_length >= 4)
<< "Cannot trivially guarantee enough distinct, unique identifiers for "
"lengths <= 3";
CARBON_CHECK(min_length >= 4,
"Cannot trivially guarantee enough distinct, unique identifiers "
"for lengths <= 3");
llvm::SmallVector<llvm::StringRef> idents =
GetIdentifiersImpl(number, min_length, max_length, uniform,
[this](int length, int length_count,
@@ -634,10 +635,10 @@ auto SourceGen::GetIdentifiersImpl(int number, int min_length, int max_length,
llvm::function_ref<AppendFn> append)
-> llvm::SmallVector<llvm::StringRef> {
CARBON_CHECK(min_length <= max_length);
CARBON_CHECK(uniform || max_length <= 64)
<< "Cannot produce a meaningful non-uniform distribution of lengths "
"longer than 64 as those are exceedingly rare in our observed data "
"sets.";
CARBON_CHECK(
uniform || max_length <= 64,
"Cannot produce a meaningful non-uniform distribution of lengths longer "
"than 64 as those are exceedingly rare in our observed data sets.");
llvm::SmallVector<llvm::StringRef> idents;
idents.reserve(number);
@@ -667,11 +668,10 @@ auto SourceGen::GetIdentifiersImpl(int number, int min_length, int max_length,
}
append(length, length_count, idents);
}
CARBON_CHECK(number_rem == 0)
<< "Unexpected number remaining: " << number_rem;
CARBON_CHECK(static_cast<int>(idents.size()) == number)
<< "Ended up with " << idents.size()
<< " identifiers instead of the requested " << number;
CARBON_CHECK(number_rem == 0, "Unexpected number remaining: {0}", number_rem);
CARBON_CHECK(static_cast<int>(idents.size()) == number,
"Ended up with {0} identifiers instead of the requested {1}",
idents.size(), number);
return idents;
}