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https://github.com/carbon-language/carbon-lang.git
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Jon Ross-Perkins
10647b70a4
Just opening files in vscode and seeing what clangd flags. Some edits to ostream.h to stop it from getting flagged (the usage pattern means it's not always obviously used).
80 lines
2.4 KiB
C++
80 lines
2.4 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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#ifndef CARBON_COMMON_CHECK_INTERNAL_H_
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#define CARBON_COMMON_CHECK_INTERNAL_H_
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#include <cstdlib>
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#include "llvm/Support/raw_ostream.h"
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namespace Carbon::Internal {
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// Wraps a stream and exiting for fatal errors. Should only be used by check.h
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// macros.
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class ExitingStream {
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public:
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// A tag type that renders as ": " in an ExitingStream, but only if it is
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// followed by additional output. Otherwise, it renders as "". Primarily used
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// when building macros around these streams.
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struct AddSeparator {};
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// Internal type used in macros to dispatch to the `operator|` overload.
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struct Helper {};
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ExitingStream()
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// Prefix the buffer with the current bug report message.
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: buffer_(buffer_str_) {}
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// Never called.
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[[noreturn]] ~ExitingStream();
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// If the bool cast occurs, it's because the condition is false. This supports
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// && short-circuiting the creation of ExitingStream.
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explicit operator bool() const { return true; }
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// Forward output to llvm::errs.
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template <typename T>
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auto operator<<(const T& message) -> ExitingStream& {
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if (separator_) {
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buffer_ << ": ";
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separator_ = false;
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}
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buffer_ << message;
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return *this;
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}
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auto operator<<(AddSeparator /*add_separator*/) -> ExitingStream& {
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separator_ = true;
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return *this;
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}
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// Low-precedence binary operator overload used in check.h macros to flush the
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// output and exit the program. We do this in a binary operator rather than
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// the destructor to ensure good debug info and backtraces for errors.
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[[noreturn]] friend auto operator|(Helper /*helper*/, ExitingStream& stream)
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-> void {
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stream.Done();
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}
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private:
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[[noreturn]] auto Done() -> void;
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// Whether a separator should be printed if << is used again.
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bool separator_ = false;
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std::string buffer_str_;
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llvm::raw_string_ostream buffer_;
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};
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} // namespace Carbon::Internal
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// Raw exiting stream. This should be used when building forms of exiting
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// macros. It evaluates to a temporary `ExitingStream` object that can be
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// manipulated, streamed into, and then will exit the program.
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#define CARBON_CHECK_INTERNAL_STREAM() \
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Carbon::Internal::ExitingStream::Helper() | Carbon::Internal::ExitingStream()
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#endif // CARBON_COMMON_CHECK_INTERNAL_H_
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