598e882ee8
Summary: Currently we dispatch the writing mode off of a runtime enum passed in by the constructor. This causes very unfortunate codegen for the GPU targets where we get worst-case codegen because of the unused function pointer for `sprintf`. Instead, this patch moves all of this to a template so it can be masked out. This results in no dynamic stack and uses 60 VGPRs instead of 117. It also compiles about 5x as fast.
39 lines
1.4 KiB
C++
39 lines
1.4 KiB
C++
//===-- Implementation of vsnprintf -----------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "src/stdio/vsnprintf.h"
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#include "src/__support/arg_list.h"
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#include "src/__support/macros/config.h"
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#include "src/stdio/printf_core/printf_main.h"
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#include "src/stdio/printf_core/writer.h"
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#include <stdarg.h>
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#include <stddef.h>
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namespace LIBC_NAMESPACE_DECL {
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LLVM_LIBC_FUNCTION(int, vsnprintf,
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(char *__restrict buffer, size_t buffsz,
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const char *__restrict format, va_list vlist)) {
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internal::ArgList args(vlist); // This holder class allows for easier copying
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// and pointer semantics, as well as handling
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// destruction automatically.
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printf_core::WriteBuffer<printf_core::Mode<
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printf_core::WriteMode::FILL_BUFF_AND_DROP_OVERFLOW>::value>
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wb(buffer, (buffsz > 0 ? buffsz - 1 : 0));
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printf_core::Writer writer(wb);
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int ret_val = printf_core::printf_main(&writer, format, args);
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if (buffsz > 0) // if the buffsz is 0 the buffer may be a null pointer.
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wb.buff[wb.buff_cur] = '\0';
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return ret_val;
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}
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} // namespace LIBC_NAMESPACE_DECL
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