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>

common/command_line.cpp

@@ -22,7 +22,7 @@ auto operator<<(llvm::raw_ostream& output, ParseResult result)
     case ParseResult::Success:
       return output << "Success";
   }
-  CARBON_FATAL() << "Corrupt parse result!";
+  CARBON_FATAL("Corrupt parse result!");
 }
 
 auto operator<<(llvm::raw_ostream& output, ArgKind kind) -> llvm::raw_ostream& {
@@ -40,7 +40,7 @@ auto operator<<(llvm::raw_ostream& output, ArgKind kind) -> llvm::raw_ostream& {
     case ArgKind::Invalid:
       return output << "Invalid";
   }
-  CARBON_FATAL() << "Corrupt argument kind!";
+  CARBON_FATAL("Corrupt argument kind!");
 }
 
 auto operator<<(llvm::raw_ostream& output, CommandKind kind)
@@ -55,7 +55,7 @@ auto operator<<(llvm::raw_ostream& output, CommandKind kind)
     case CommandKind::MetaAction:
       return output << "MetaAction";
   }
-  CARBON_FATAL() << "Corrupt command kind!";
+  CARBON_FATAL("Corrupt command kind!");
 }
 Arg::Arg(const ArgInfo& info) : info(info) {}
 
@@ -315,8 +315,9 @@ void MetaPrinter::PrintHelpForSubcommandName(
 }
 
 void MetaPrinter::PrintVersion(const Command& command) const {
-  CARBON_CHECK(!command.info.version.empty())
-      << "Printing should not be enabled without a version string configured.";
+  CARBON_CHECK(
+      !command.info.version.empty(),
+      "Printing should not be enabled without a version string configured.");
   PrintRawVersion(command, /*indent=*/"");
   if (!command.info.build_info.empty()) {
     out_ << "\n";
@@ -463,13 +464,14 @@ void MetaPrinter::PrintOptionUsage(const Arg& option) const {
 }
 
 void MetaPrinter::PrintOptionShortName(const Arg& arg) const {
-  CARBON_CHECK(!arg.info.short_name.empty()) << "No short name to use.";
+  CARBON_CHECK(!arg.info.short_name.empty(), "No short name to use.");
   out_ << "-" << arg.info.short_name;
 }
 
 void MetaPrinter::PrintArgShortValues(const Arg& arg) const {
-  CARBON_CHECK(arg.kind == Arg::Kind::OneOf)
-      << "Only one-of arguments have interesting value snippets to print.";
+  CARBON_CHECK(
+      arg.kind == Arg::Kind::OneOf,
+      "Only one-of arguments have interesting value snippets to print.");
   llvm::ListSeparator sep;
   for (llvm::StringRef value_string : arg.value_strings) {
     out_ << sep << value_string;
@@ -517,7 +519,7 @@ void MetaPrinter::PrintArgHelp(const Arg& arg, llvm::StringRef indent) const {
       // No value help.
       break;
     case Arg::Kind::Invalid:
-      CARBON_FATAL() << "Argument configured without any action or kind!";
+      CARBON_FATAL("Argument configured without any action or kind!");
   }
 }
 
@@ -793,11 +795,11 @@ void Parser::PopulateMaps(const Command& command) {
     if (option->info.short_name.empty()) {
       continue;
     }
-    CARBON_CHECK(option->info.short_name.size() == 1)
-        << "Short option names must have exactly one character.";
+    CARBON_CHECK(option->info.short_name.size() == 1,
+                 "Short option names must have exactly one character.");
     unsigned char short_char = option->info.short_name[0];
-    CARBON_CHECK(short_char < short_option_table_.size())
-        << "Short option name outside of the expected range.";
+    CARBON_CHECK(short_char < short_option_table_.size(),
+                 "Short option name outside of the expected range.");
     short_option_table_[short_char] = &map_entry.second;
   }
   subcommand_map_.clear();
@@ -807,7 +809,7 @@ void Parser::PopulateMaps(const Command& command) {
 }
 
 void Parser::SetOptionDefault(const Arg& option) {
-  CARBON_CHECK(option.has_default) << "No default value available!";
+  CARBON_CHECK(option.has_default, "No default value available!");
   switch (option.kind) {
     case Arg::Kind::Flag:
       *option.flag_storage = option.default_flag;
@@ -822,9 +824,9 @@ void Parser::SetOptionDefault(const Arg& option) {
       option.default_action(option);
       break;
     case Arg::Kind::MetaActionOnly:
-      CARBON_FATAL() << "Can't set a default value for a meta action!";
+      CARBON_FATAL("Can't set a default value for a meta action!");
     case Arg::Kind::Invalid:
-      CARBON_FATAL() << "Option configured without any action or kind!";
+      CARBON_FATAL("Option configured without any action or kind!");
   }
 }
 
@@ -846,7 +848,7 @@ auto Parser::ParseNegatedFlag(const Arg& flag,
 
 auto Parser::ParseFlag(const Arg& flag, std::optional<llvm::StringRef> value)
     -> bool {
-  CARBON_CHECK(flag.kind == Arg::Kind::Flag) << "Incorrect kind: " << flag.kind;
+  CARBON_CHECK(flag.kind == Arg::Kind::Flag, "Incorrect kind: {0}", flag.kind);
   if (!value || *value == "true") {
     *flag.flag_storage = true;
   } else if (*value == "false") {
@@ -862,8 +864,7 @@ auto Parser::ParseFlag(const Arg& flag, std::optional<llvm::StringRef> value)
 
 auto Parser::ParseIntegerArgValue(const Arg& arg, llvm::StringRef value)
     -> bool {
-  CARBON_CHECK(arg.kind == Arg::Kind::Integer)
-      << "Incorrect kind: " << arg.kind;
+  CARBON_CHECK(arg.kind == Arg::Kind::Integer, "Incorrect kind: {0}", arg.kind);
   int integer_value;
   // Note that this method returns *true* on error!
   if (value.getAsInteger(/*Radix=*/0, integer_value)) {
@@ -881,7 +882,7 @@ auto Parser::ParseIntegerArgValue(const Arg& arg, llvm::StringRef value)
 
 auto Parser::ParseStringArgValue(const Arg& arg, llvm::StringRef value)
     -> bool {
-  CARBON_CHECK(arg.kind == Arg::Kind::String) << "Incorrect kind: " << arg.kind;
+  CARBON_CHECK(arg.kind == Arg::Kind::String, "Incorrect kind: {0}", arg.kind);
   if (!arg.is_append) {
     *arg.string_storage = value;
   } else {
@@ -891,7 +892,7 @@ auto Parser::ParseStringArgValue(const Arg& arg, llvm::StringRef value)
 }
 
 auto Parser::ParseOneOfArgValue(const Arg& arg, llvm::StringRef value) -> bool {
-  CARBON_CHECK(arg.kind == Arg::Kind::OneOf) << "Incorrect kind: " << arg.kind;
+  CARBON_CHECK(arg.kind == Arg::Kind::OneOf, "Incorrect kind: {0}", arg.kind);
   if (!arg.value_action(arg, value)) {
     errors_ << "ERROR: Option '--" << arg.info.name << "=";
     llvm::printEscapedString(value, errors_);
@@ -967,7 +968,7 @@ auto Parser::ParseArg(const Arg& arg, bool short_spelling,
       return false;
     case Arg::Kind::Flag:
     case Arg::Kind::Invalid:
-      CARBON_FATAL() << "Invalid kind!";
+      CARBON_FATAL("Invalid kind!");
   }
 }
 
@@ -984,8 +985,8 @@ auto Parser::SplitValue(llvm::StringRef& unparsed_arg)
 }
 
 auto Parser::ParseLongOption(llvm::StringRef unparsed_arg) -> bool {
-  CARBON_CHECK(unparsed_arg.starts_with("--") && unparsed_arg.size() > 2)
-      << "Must only be called on a potential long option.";
+  CARBON_CHECK(unparsed_arg.starts_with("--") && unparsed_arg.size() > 2,
+               "Must only be called on a potential long option.");
 
   // Walk past the double dash.
   unparsed_arg = unparsed_arg.drop_front(2);
@@ -1009,8 +1010,8 @@ auto Parser::ParseLongOption(llvm::StringRef unparsed_arg) -> bool {
 }
 
 auto Parser::ParseShortOptionSeq(llvm::StringRef unparsed_arg) -> bool {
-  CARBON_CHECK(unparsed_arg.starts_with("-") && unparsed_arg.size() > 1)
-      << "Must only be called on a potential short option sequence.";
+  CARBON_CHECK(unparsed_arg.starts_with("-") && unparsed_arg.size() > 1,
+               "Must only be called on a potential short option sequence.");
 
   unparsed_arg = unparsed_arg.drop_front();
   std::optional<llvm::StringRef> value = SplitValue(unparsed_arg);
@@ -1143,10 +1144,10 @@ auto Parser::FinalizeParse() -> ParseResult {
   // If we were appending to a positional argument, mark that as complete.
   llvm::ArrayRef positional_args = command_->positional_args;
   if (appending_to_positional_arg_) {
-    CARBON_CHECK(static_cast<size_t>(positional_arg_index_) <
-                 positional_args.size())
-        << "Appending to a positional argument with an invalid index: "
-        << positional_arg_index_;
+    CARBON_CHECK(
+        static_cast<size_t>(positional_arg_index_) < positional_args.size(),
+        "Appending to a positional argument with an invalid index: {0}",
+        positional_arg_index_);
     ++positional_arg_index_;
   }
 
@@ -1162,15 +1163,15 @@ auto Parser::FinalizeParse() -> ParseResult {
       return ParseResult::Error;
     }
     for (const auto& arg_ptr : unparsed_positional_args) {
-      CARBON_CHECK(!arg_ptr->is_required)
-          << "Cannot have required positional parameters after an optional "
-             "one.";
+      CARBON_CHECK(
+          !arg_ptr->is_required,
+          "Cannot have required positional parameters after an optional one.");
     }
   }
 
   switch (command_->kind) {
     case Command::Kind::Invalid:
-      CARBON_FATAL() << "Should never have a parser with an invalid command!";
+      CARBON_FATAL("Should never have a parser with an invalid command!");
     case Command::Kind::RequiresSubcommand:
       errors_ << "ERROR: No subcommand specified. Available subcommands: ";
       error_meta_printer_.PrintSubcommands(*command_);
@@ -1189,11 +1190,13 @@ auto Parser::FinalizeParse() -> ParseResult {
 
 auto Parser::ParsePositionalSuffix(
     llvm::ArrayRef<llvm::StringRef> unparsed_args) -> bool {
-  CARBON_CHECK(!command_->positional_args.empty())
-      << "Cannot do positional suffix parsing without positional arguments!";
-  CARBON_CHECK(!unparsed_args.empty() && unparsed_args.front() == "--")
-      << "Must be called with a suffix of arguments starting with a `--` that "
-         "switches to positional suffix parsing.";
+  CARBON_CHECK(
+      !command_->positional_args.empty(),
+      "Cannot do positional suffix parsing without positional arguments!");
+  CARBON_CHECK(
+      !unparsed_args.empty() && unparsed_args.front() == "--",
+      "Must be called with a suffix of arguments starting with a `--` that "
+      "switches to positional suffix parsing.");
   // Once we're in the positional suffix, we can track empty positional
   // arguments.
   bool empty_positional = false;
@@ -1291,9 +1294,9 @@ auto Parser::Parse(llvm::ArrayRef<llvm::StringRef> unparsed_args)
       continue;
     }
 
-    CARBON_CHECK(command_->positional_args.empty() ||
-                 command_->subcommands.empty())
-        << "Cannot have both positional arguments and subcommands!";
+    CARBON_CHECK(
+        command_->positional_args.empty() || command_->subcommands.empty(),
+        "Cannot have both positional arguments and subcommands!");
     if (command_->positional_args.empty() && command_->subcommands.empty()) {
       errors_ << "ERROR: Found unexpected positional argument or subcommand: '"
               << unparsed_arg << "'\n";
@@ -1439,12 +1442,13 @@ void CommandBuilder::AddOneOfPositionalArg(
 
 void CommandBuilder::AddSubcommand(
     const CommandInfo& info, llvm::function_ref<void(CommandBuilder&)> build) {
-  CARBON_CHECK(IsValidName(info.name))
-      << "Invalid subcommand name: " << info.name;
-  CARBON_CHECK(subcommand_names_.insert(info.name).second)
-      << "Added a duplicate subcommand: " << info.name;
-  CARBON_CHECK(command_.positional_args.empty())
-      << "Cannot add subcommands to a command with a positional argument.";
+  CARBON_CHECK(IsValidName(info.name), "Invalid subcommand name: {0}",
+               info.name);
+  CARBON_CHECK(subcommand_names_.insert(info.name).second,
+               "Added a duplicate subcommand: {0}", info.name);
+  CARBON_CHECK(
+      command_.positional_args.empty(),
+      "Cannot add subcommands to a command with a positional argument.");
 
   command_.subcommands.emplace_back(new Command(info, &command_));
   CommandBuilder builder(*command_.subcommands.back(), meta_printer_);
@@ -1457,25 +1461,28 @@ void CommandBuilder::HelpHidden(bool is_help_hidden) {
 }
 
 void CommandBuilder::RequiresSubcommand() {
-  CARBON_CHECK(!command_.subcommands.empty())
-      << "Cannot require subcommands unless there are subcommands.";
-  CARBON_CHECK(command_.positional_args.empty())
-      << "Cannot require subcommands and have a positional argument.";
-  CARBON_CHECK(command_.kind == Kind::Invalid)
-      << "Already established the kind of this command as: " << command_.kind;
+  CARBON_CHECK(!command_.subcommands.empty(),
+               "Cannot require subcommands unless there are subcommands.");
+  CARBON_CHECK(command_.positional_args.empty(),
+               "Cannot require subcommands and have a positional argument.");
+  CARBON_CHECK(command_.kind == Kind::Invalid,
+               "Already established the kind of this command as: {0}",
+               command_.kind);
   command_.kind = Kind::RequiresSubcommand;
 }
 
 void CommandBuilder::Do(ActionT action) {
-  CARBON_CHECK(command_.kind == Kind::Invalid)
-      << "Already established the kind of this command as: " << command_.kind;
+  CARBON_CHECK(command_.kind == Kind::Invalid,
+               "Already established the kind of this command as: {0}",
+               command_.kind);
   command_.kind = Kind::Action;
   command_.action = std::move(action);
 }
 
 void CommandBuilder::Meta(ActionT action) {
-  CARBON_CHECK(command_.kind == Kind::Invalid)
-      << "Already established the kind of this command as: " << command_.kind;
+  CARBON_CHECK(command_.kind == Kind::Invalid,
+               "Already established the kind of this command as: {0}",
+               command_.kind);
   command_.kind = Kind::MetaAction;
   command_.action = std::move(action);
 }
@@ -1484,10 +1491,9 @@ CommandBuilder::CommandBuilder(Command& command, MetaPrinter& meta_printer)
     : command_(command), meta_printer_(meta_printer) {}
 
 auto CommandBuilder::AddArgImpl(const ArgInfo& info, Arg::Kind kind) -> Arg& {
-  CARBON_CHECK(IsValidName(info.name))
-      << "Invalid argument name: " << info.name;
-  CARBON_CHECK(arg_names_.insert(info.name).second)
-      << "Added a duplicate argument name: " << info.name;
+  CARBON_CHECK(IsValidName(info.name), "Invalid argument name: {0}", info.name);
+  CARBON_CHECK(arg_names_.insert(info.name).second,
+               "Added a duplicate argument name: {0}", info.name);
 
   command_.options.emplace_back(new Arg(info));
   Arg& arg = *command_.options.back();
@@ -1497,23 +1503,23 @@ auto CommandBuilder::AddArgImpl(const ArgInfo& info, Arg::Kind kind) -> Arg& {
 
 void CommandBuilder::AddPositionalArgImpl(
     const ArgInfo& info, Arg::Kind kind, llvm::function_ref<void(Arg&)> build) {
-  CARBON_CHECK(IsValidName(info.name))
-      << "Invalid argument name: " << info.name;
-  CARBON_CHECK(command_.subcommands.empty())
-      << "Cannot add a positional argument to a command with subcommands.";
+  CARBON_CHECK(IsValidName(info.name), "Invalid argument name: {0}", info.name);
+  CARBON_CHECK(
+      command_.subcommands.empty(),
+      "Cannot add a positional argument to a command with subcommands.");
 
   command_.positional_args.emplace_back(new Arg(info));
   Arg& arg = *command_.positional_args.back();
   arg.kind = kind;
   build(arg);
 
-  CARBON_CHECK(!arg.is_help_hidden)
-      << "Cannot have a help-hidden positional argument.";
+  CARBON_CHECK(!arg.is_help_hidden,
+               "Cannot have a help-hidden positional argument.");
 
   if (arg.is_required && command_.positional_args.size() > 1) {
-    CARBON_CHECK((*std::prev(command_.positional_args.end(), 2))->is_required)
-        << "A required positional argument cannot be added after an optional "
-           "one.";
+    CARBON_CHECK((*std::prev(command_.positional_args.end(), 2))->is_required,
+                 "A required positional argument cannot be added after an "
+                 "optional one.");
   }
 }