mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-10-01 14:45:53 +01:00
4845f40dff
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>
55 lines
2.1 KiB
C++
55 lines
2.1 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
|
|
// Exceptions. See /LICENSE for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
|
|
#ifndef CARBON_COMMON_CHECK_H_
|
|
#define CARBON_COMMON_CHECK_H_
|
|
|
|
#include "common/check_internal.h"
|
|
|
|
namespace Carbon {
|
|
|
|
// Checks the given condition, and if it's false, prints a stack, streams the
|
|
// error message, then exits. This should be used for unexpected errors, such as
|
|
// a bug in the application.
|
|
//
|
|
// For example:
|
|
// CARBON_CHECK(is_valid, "Data is not valid!");
|
|
//
|
|
// The condition must be parenthesized if it contains top-level commas, for
|
|
// example in a template argument list:
|
|
// CARBON_CHECK((inst.IsOneOf<Call, TupleLiteral>()),
|
|
// "Unexpected inst {0}", inst);
|
|
#define CARBON_CHECK(condition, ...) \
|
|
(condition) ? (void)0 \
|
|
: CARBON_INTERNAL_CHECK(condition __VA_OPT__(, ) __VA_ARGS__)
|
|
|
|
// DCHECK calls CHECK in debug mode, and does nothing otherwise.
|
|
#ifndef NDEBUG
|
|
#define CARBON_DCHECK(condition, ...) \
|
|
CARBON_CHECK(condition __VA_OPT__(, ) __VA_ARGS__)
|
|
#else
|
|
// When in a debug build we want to preserve as much as we can of how the
|
|
// parameters are used, other than making them be trivially in dead code and
|
|
// eliminated by the optimizer. As a consequence we preserve the condition but
|
|
// prefix it with a short-circuit operator, and we still emit the (dead) call to
|
|
// the check implementation. But we use a special implementation that reduces
|
|
// the compile time cost.
|
|
#define CARBON_DCHECK(condition, ...) \
|
|
(true || (condition)) \
|
|
? (void)0 \
|
|
: CARBON_INTERNAL_DEAD_DCHECK(condition __VA_OPT__(, ) __VA_ARGS__)
|
|
#endif
|
|
|
|
// This is similar to CHECK, but is unconditional. Writing
|
|
// `CARBON_FATAL("message")` is clearer than `CARBON_CHECK(false, "message")
|
|
// because it avoids confusion about control flow.
|
|
//
|
|
// For example:
|
|
// CARBON_FATAL("Unreachable!");
|
|
#define CARBON_FATAL(...) CARBON_INTERNAL_FATAL(__VA_ARGS__)
|
|
|
|
} // namespace Carbon
|
|
|
|
#endif // CARBON_COMMON_CHECK_H_
|