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[libc][NFC] Allow memset (and bzero) to be inlined 

This allows shipping individual functions without also having to provide
memset or bzero at the expense of bigger functions.

Similar to D113097.

Differential Revision: https://reviews.llvm.org/D113108
This commit is contained in:
Guillaume Chatelet 2021-11-04 12:14:31 +00:00
parent 4f3511e28f
commit c02aa15438
5 changed files with 67 additions and 66 deletions

5
libc/src/string/CMakeLists.txt
View File

@ -389,7 +389,7 @@ endif()
function(add_memset memset_name)
add_implementation(memset ${memset_name}
SRCS ${MEMSET_SRC}
SRCS ${LIBC_SOURCE_DIR}/src/string/memset.cpp
HDRS ${LIBC_SOURCE_DIR}/src/string/memset.h
DEPENDS
.memory_utils.memory_utils
@ -401,7 +401,6 @@ function(add_memset memset_name)
endfunction()
if(${LIBC_TARGET_ARCHITECTURE_IS_X86})
set(MEMSET_SRC ${LIBC_SOURCE_DIR}/src/string/memset.cpp)
add_memset(memset_x86_64_opt_sse2 COMPILE_OPTIONS -march=k8 REQUIRE SSE2)
add_memset(memset_x86_64_opt_sse4 COMPILE_OPTIONS -march=nehalem REQUIRE SSE4_2)
add_memset(memset_x86_64_opt_avx2 COMPILE_OPTIONS -march=haswell REQUIRE AVX2)
@ -409,12 +408,10 @@ if(${LIBC_TARGET_ARCHITECTURE_IS_X86})
add_memset(memset_opt_host COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE})
add_memset(memset)
elseif(${LIBC_TARGET_ARCHITECTURE_IS_AARCH64})
set(MEMSET_SRC ${LIBC_SOURCE_DIR}/src/string/aarch64/memset.cpp)
add_memset(memset_opt_host COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE}
COMPILE_OPTIONS "SHELL:-mllvm --tail-merge-threshold=0")
add_memset(memset COMPILE_OPTIONS "SHELL:-mllvm --tail-merge-threshold=0")
else()
set(MEMSET_SRC ${LIBC_SOURCE_DIR}/src/string/memset.cpp)
add_memset(memset_opt_host COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE})
add_memset(memset)
endif()

49
libc/src/string/aarch64/memset.cpp
View File

@ -1,49 +0,0 @@
//===-- Implementation of memset ------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "src/string/memset.h"
#include "src/__support/common.h"
#include "src/string/memory_utils/memset_utils.h"
namespace __llvm_libc {
using namespace __llvm_libc::aarch64_memset;
inline static void AArch64Memset(char *dst, int value, size_t count) {
if (count == 0)
return;
if (count <= 3) {
SplatSet<_1>(dst, value);
if (count > 1)
SplatSet<Tail<_2>>(dst, value, count);
return;
}
if (count <= 8)
return SplatSet<HeadTail<_4>>(dst, value, count);
if (count <= 16)
return SplatSet<HeadTail<_8>>(dst, value, count);
if (count <= 32)
return SplatSet<HeadTail<_16>>(dst, value, count);
if (count <= 96) {
SplatSet<_32>(dst, value);
if (count <= 64)
return SplatSet<Tail<_32>>(dst, value, count);
SplatSet<Skip<32>::Then<_32>>(dst, value);
SplatSet<Tail<_32>>(dst, value, count);
return;
}
if (count < 448 || value != 0 || !AArch64ZVA(dst, count))
return SplatSet<Align<_16, Arg::_1>::Then<Loop<_64>>>(dst, value, count);
}
LLVM_LIBC_FUNCTION(void *, memset, (void *dst, int value, size_t count)) {
AArch64Memset((char *)dst, value, count);
return dst;
}
} // namespace __llvm_libc

4
libc/src/string/bzero.cpp
View File

@ -8,12 +8,12 @@
#include "src/string/bzero.h"
#include "src/__support/common.h"
#include "src/string/memory_utils/memset_utils.h"
#include "src/string/memory_utils/memset_implementations.h"
namespace __llvm_libc {
LLVM_LIBC_FUNCTION(void, bzero, (void *ptr, size_t count)) {
GeneralPurposeMemset(reinterpret_cast<char *>(ptr), 0, count);
inline_memset(reinterpret_cast<char *>(ptr), 0, count);
}
} // namespace __llvm_libc

69
libc/src/string/memory_utils/memset_utils.h → libc/src/string/memory_utils/memset_implementations.h
View File

@ -1,4 +1,4 @@
//===-- Memset utils --------------------------------------------*- C++ -*-===//
//===-- Implementation of memset and bzero --------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
@ -6,8 +6,8 @@
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC_STRING_MEMORY_UTILS_MEMSET_UTILS_H
#define LLVM_LIBC_SRC_STRING_MEMORY_UTILS_MEMSET_UTILS_H
#ifndef LLVM_LIBC_SRC_STRING_MEMORY_UTILS_MEMSET_IMPLEMENTATIONS_H
#define LLVM_LIBC_SRC_STRING_MEMORY_UTILS_MEMSET_IMPLEMENTATIONS_H
#include "src/__support/architectures.h"
#include "src/string/memory_utils/elements.h"
@ -48,13 +48,65 @@ namespace __llvm_libc {
// advance. SetAlignedBlocks<64> may waste up to 63 Bytes, SetAlignedBlocks<32>
// may waste up to 31 Bytes. Benchmarks showed that SetAlignedBlocks<64> was not
// superior for sizes that mattered.
inline static void GeneralPurposeMemset(char *dst, unsigned char value,
size_t count) {
inline static void inline_memset(char *dst, unsigned char value, size_t count) {
#if defined(LLVM_LIBC_ARCH_X86)
using namespace ::__llvm_libc::x86;
/////////////////////////////////////////////////////////////////////////////
// LLVM_LIBC_ARCH_X86
/////////////////////////////////////////////////////////////////////////////
using namespace __llvm_libc::x86;
if (count == 0)
return;
if (count == 1)
return SplatSet<_1>(dst, value);
if (count == 2)
return SplatSet<_2>(dst, value);
if (count == 3)
return SplatSet<_3>(dst, value);
if (count <= 8)
return SplatSet<HeadTail<_4>>(dst, value, count);
if (count <= 16)
return SplatSet<HeadTail<_8>>(dst, value, count);
if (count <= 32)
return SplatSet<HeadTail<_16>>(dst, value, count);
if (count <= 64)
return SplatSet<HeadTail<_32>>(dst, value, count);
if (count <= 128)
return SplatSet<HeadTail<_64>>(dst, value, count);
return SplatSet<Align<_32, Arg::Dst>::Then<Loop<_32>>>(dst, value, count);
#elif defined(LLVM_LIBC_ARCH_AARCH64)
/////////////////////////////////////////////////////////////////////////////
// LLVM_LIBC_ARCH_AARCH64
/////////////////////////////////////////////////////////////////////////////
using namespace __llvm_libc::aarch64_memset;
if (count == 0)
return;
if (count <= 3) {
SplatSet<_1>(dst, value);
if (count > 1)
SplatSet<Tail<_2>>(dst, value, count);
return;
}
if (count <= 8)
return SplatSet<HeadTail<_4>>(dst, value, count);
if (count <= 16)
return SplatSet<HeadTail<_8>>(dst, value, count);
if (count <= 32)
return SplatSet<HeadTail<_16>>(dst, value, count);
if (count <= 96) {
SplatSet<_32>(dst, value);
if (count <= 64)
return SplatSet<Tail<_32>>(dst, value, count);
SplatSet<Skip<32>::Then<_32>>(dst, value);
SplatSet<Tail<_32>>(dst, value, count);
return;
}
if (count < 448 || value != 0 || !AArch64ZVA(dst, count))
return SplatSet<Align<_16, Arg::_1>::Then<Loop<_64>>>(dst, value, count);
#else
/////////////////////////////////////////////////////////////////////////////
// Default
/////////////////////////////////////////////////////////////////////////////
using namespace ::__llvm_libc::scalar;
#endif
if (count == 0)
return;
@ -75,8 +127,9 @@ inline static void GeneralPurposeMemset(char *dst, unsigned char value,
if (count <= 128)
return SplatSet<HeadTail<_64>>(dst, value, count);
return SplatSet<Align<_32, Arg::Dst>::Then<Loop<_32>>>(dst, value, count);
#endif
}
} // namespace __llvm_libc
#endif // LLVM_LIBC_SRC_STRING_MEMORY_UTILS_MEMSET_UTILS_H
#endif // LLVM_LIBC_SRC_STRING_MEMORY_UTILS_MEMSET_IMPLEMENTATIONS_H

6
libc/src/string/memset.cpp
View File

@ -8,13 +8,13 @@
#include "src/string/memset.h"
#include "src/__support/common.h"
#include "src/string/memory_utils/memset_utils.h"
#include "src/string/memory_utils/memset_implementations.h"
namespace __llvm_libc {
LLVM_LIBC_FUNCTION(void *, memset, (void *dst, int value, size_t count)) {
GeneralPurposeMemset(reinterpret_cast<char *>(dst),
static_cast<unsigned char>(value), count);
inline_memset(reinterpret_cast<char *>(dst),
static_cast<unsigned char>(value), count);
return dst;
}