Switch CARBON_CHECK to a format string API (#4285)

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>

toolchain/parse/context.cpp

@@ -59,11 +59,11 @@ Context::Context(Tree& tree, Lex::TokenizedBuffer& tokens,
       vlog_stream_(vlog_stream),
       position_(tokens_->tokens().begin()),
       end_(tokens_->tokens().end()) {
-  CARBON_CHECK(position_ != end_) << "Empty TokenizedBuffer";
+  CARBON_CHECK(position_ != end_, "Empty TokenizedBuffer");
   --end_;
-  CARBON_CHECK(tokens_->GetKind(*end_) == Lex::TokenKind::FileEnd)
-      << "TokenizedBuffer should end with FileEnd, ended with "
-      << tokens_->GetKind(*end_);
+  CARBON_CHECK(tokens_->GetKind(*end_) == Lex::TokenKind::FileEnd,
+               "TokenizedBuffer should end with FileEnd, ended with {0}",
+               tokens_->GetKind(*end_));
 }
 
 auto Context::AddLeafNode(NodeKind kind, Lex::TokenIndex token, bool has_error)
@@ -79,8 +79,8 @@ auto Context::AddNode(NodeKind kind, Lex::TokenIndex token, bool has_error)
 auto Context::ReplacePlaceholderNode(int32_t position, NodeKind kind,
                                      Lex::TokenIndex token, bool has_error)
     -> void {
-  CARBON_CHECK(position >= 0 && position < tree_->size())
-      << "position: " << position << " size: " << tree_->size();
+  CARBON_CHECK(position >= 0 && position < tree_->size(),
+               "position: {0} size: {1}", position, tree_->size());
   auto* node_impl = &tree_->node_impls_[position];
   CARBON_CHECK(node_impl->kind == NodeKind::Placeholder);
   node_impl->kind = kind;
@@ -138,8 +138,8 @@ auto Context::ConsumeAndAddLeafNodeIf(Lex::TokenKind token_kind,
 }
 
 auto Context::ConsumeChecked(Lex::TokenKind kind) -> Lex::TokenIndex {
-  CARBON_CHECK(PositionIs(kind))
-      << "Required " << kind << ", found " << PositionKind();
+  CARBON_CHECK(PositionIs(kind), "Required {0}, found {1}", kind,
+               PositionKind());
   return Consume();
 }
 
@@ -230,10 +230,10 @@ auto Context::SkipPastLikelyEnd(Lex::TokenIndex skip_root) -> Lex::TokenIndex {
 }
 
 auto Context::SkipTo(Lex::TokenIndex t) -> void {
-  CARBON_CHECK(t >= *position_) << "Tried to skip backwards from " << position_
-                                << " to " << Lex::TokenIterator(t);
+  CARBON_CHECK(t >= *position_, "Tried to skip backwards from {0} to {1}",
+               position_, Lex::TokenIterator(t));
   position_ = Lex::TokenIterator(t);
-  CARBON_CHECK(position_ != end_) << "Skipped past EOF.";
+  CARBON_CHECK(position_ != end_, "Skipped past EOF.");
 }
 
 // Determines whether the given token is considered to be the start of an
@@ -265,7 +265,7 @@ static auto IsPossibleStartOfOperand(Lex::TokenKind kind) -> bool {
 }
 
 auto Context::IsLexicallyValidInfixOperator() -> bool {
-  CARBON_CHECK(position_ != end_) << "Expected an operator token.";
+  CARBON_CHECK(position_ != end_, "Expected an operator token.");
 
   bool leading_space = tokens().HasLeadingWhitespace(*position_);
   bool trailing_space = tokens().HasTrailingWhitespace(*position_);
@@ -371,9 +371,8 @@ auto Context::ConsumeListToken(NodeKind comma_kind, Lex::TokenKind close_kind,
     // Recover from the invalid token.
     auto end_of_element = FindNextOf({Lex::TokenKind::Comma, close_kind});
     // The lexer guarantees that parentheses are balanced.
-    CARBON_CHECK(end_of_element)
-        << "missing matching `" << close_kind.opening_symbol() << "` for `"
-        << close_kind << "`";
+    CARBON_CHECK(end_of_element, "missing matching `{0}` for `{1}`",
+                 close_kind.opening_symbol(), close_kind);
 
     SkipTo(*end_of_element);
   }