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35 lines
1.2 KiB
C++
35 lines
1.2 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#include "toolchain/lexer/lex_helpers.h"
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#include "llvm/Support/FormatVariadic.h"
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namespace Carbon {
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auto CanLexInteger(DiagnosticEmitter<const char*>& emitter,
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llvm::StringRef text) -> bool {
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// llvm::getAsInteger is used for parsing, but it's quadratic and visibly slow
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// on large integer values. This limit exists to avoid hitting those limits.
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// Per https://github.com/carbon-language/carbon-lang/issues/980, it may be
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// feasible to optimize integer parsing in order to address performance if
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// this limit becomes an issue.
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//
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// 2^128 would be 39 decimal digits or 128 binary. In either case, this limit
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// is far above the threshold for normal integers.
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constexpr size_t DigitLimit = 1000;
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if (text.size() > DigitLimit) {
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CARBON_DIAGNOSTIC(
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TooManyDigits, Error,
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"Found a sequence of {0} digits, which is greater than the "
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"limit of {1}.",
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size_t, size_t);
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emitter.Emit(text.begin(), TooManyDigits, text.size(), DigitLimit);
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return false;
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}
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return true;
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}
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} // namespace Carbon
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