[libc-commits] [libc] POC: add snmalloc as an alternative allocator to libc (PR #122284)
via libc-commits
libc-commits at lists.llvm.org
Wed Jan 15 22:22:36 PST 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-libc
Author: Schrodinger ZHU Yifan (SchrodingerZhu)
<details>
<summary>Changes</summary>
Does not work yet. I need to work out a lot more details. This is for collecting ideas.
`snmalloc` is already supported in LLVM for windows CRT replacement, we can also use it as an implementation of our allocator:
https://github.com/llvm/llvm-project/blob/aa0191e3feccf8253f16594922ee924b38e7760d/llvm/lib/Support/CMakeLists.txt#L101
Adding snmalloc will push forward our support on windows/macos easily. It also provides linux target with a modern allocator alternative.
I have made snmalloc buildable with clean C headers in https://github.com/microsoft/snmalloc/pull/722, hence, it can now be used in a way largely similar to scudo standalone allocator.
`malloc.cpp.o` is already buildable with some ad-hoc fixes, so I think there is no technical obstacle.
---
Full diff: https://github.com/llvm/llvm-project/pull/122284.diff
10 Files Affected:
- (modified) libc/src/stdlib/CMakeLists.txt (+40-1)
- (added) libc/src/stdlib/snmalloc/CMakeLists.txt (+119)
- (added) libc/src/stdlib/snmalloc/aligned_alloc.cpp (+17)
- (added) libc/src/stdlib/snmalloc/calloc.cpp (+17)
- (added) libc/src/stdlib/snmalloc/free.cpp (+17)
- (added) libc/src/stdlib/snmalloc/malloc.cpp (+17)
- (added) libc/src/stdlib/snmalloc/mallopt.cpp (+13)
- (added) libc/src/stdlib/snmalloc/override.h (+32)
- (added) libc/src/stdlib/snmalloc/realloc.cpp (+17)
- (modified) libc/test/src/stdlib/CMakeLists.txt (+3-1)
``````````diff
diff --git a/libc/src/stdlib/CMakeLists.txt b/libc/src/stdlib/CMakeLists.txt
index 40ba9ead9a7ae6..7d0dfd1aa9da4b 100644
--- a/libc/src/stdlib/CMakeLists.txt
+++ b/libc/src/stdlib/CMakeLists.txt
@@ -324,7 +324,46 @@ add_entrypoint_object(
)
if(NOT LIBC_TARGET_OS_IS_BAREMETAL AND NOT LIBC_TARGET_OS_IS_GPU)
- if(LLVM_LIBC_INCLUDE_SCUDO)
+ if (NOT "${LLVM_LIBC_INCLUDE_SNMALLOC}" STREQUAL "")
+ message(STATUS "Including snmalloc as the allocator, source directory: ${LLVM_LIBC_INCLUDE_SNMALLOC}")
+ add_subdirectory(snmalloc)
+ add_entrypoint_object(
+ malloc
+ ALIAS
+ DEPENDS
+ .snmalloc.malloc
+ )
+ add_entrypoint_object(
+ calloc
+ ALIAS
+ DEPENDS
+ .snmalloc.calloc
+ )
+ add_entrypoint_object(
+ realloc
+ ALIAS
+ DEPENDS
+ .snmalloc.realloc
+ )
+ add_entrypoint_object(
+ aligned_alloc
+ ALIAS
+ DEPENDS
+ .snmalloc.aligned_alloc
+ )
+ add_entrypoint_object(
+ free
+ ALIAS
+ DEPENDS
+ .snmalloc.free
+ )
+ add_entrypoint_object(
+ mallopt
+ ALIAS
+ DEPENDS
+ .snmalloc.mallopt
+ )
+ elseif(LLVM_LIBC_INCLUDE_SCUDO)
set(SCUDO_DEPS "")
include(${LIBC_SOURCE_DIR}/../compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake)
diff --git a/libc/src/stdlib/snmalloc/CMakeLists.txt b/libc/src/stdlib/snmalloc/CMakeLists.txt
new file mode 100644
index 00000000000000..e360b36f5fb3ad
--- /dev/null
+++ b/libc/src/stdlib/snmalloc/CMakeLists.txt
@@ -0,0 +1,119 @@
+set(SNMALLOC_USE_SELF_VENDORED_STL ON CACHE BOOL "use freestanding snmalloc setup" FORCE)
+set(SNMALLOC_BUILD_TESTING OFF CACHE BOOL "disable snmalloc tests" FORCE)
+set(SNMALLOC_HEADER_ONLY_LIBRARY ON CACHE BOOL "use snmalloc as header only library" FORCE)
+
+# Disable installation
+macro (install)
+endmacro ()
+
+add_subdirectory(${LLVM_LIBC_INCLUDE_SNMALLOC} ${CMAKE_CURRENT_BINARY_DIR}/snmalloc EXCLUDE_FROM_ALL)
+
+target_compile_options(
+ snmalloc
+ INTERFACE
+ -ffreestanding
+ -nostdinc
+ -Wno-newline-eof
+ -Wno-extra-semi
+ -Wno-unused-command-line-argument
+ -Wno-ctad-maybe-unsupported
+ # TODO: define this
+ -DSTDERR_FILENO=2
+ -DSNMALLOC_USE_PTHREAD_DESTRUCTORS
+ # include_directories does not propagate, use options instead
+ -include ${CMAKE_CURRENT_SOURCE_DIR}/override.h
+ -isystem ${COMPILER_RESOURCE_DIR}/include
+ -isystem ${LIBC_INCLUDE_DIR}
+)
+
+add_dependencies(snmalloc libc-headers)
+
+set(SNMALLOC_DEPS
+ # includes
+ libc.include.errno
+ libc.include.fcntl
+ libc.include.limits
+ libc.include.pthread
+ libc.include.stdio
+ libc.include.stdint
+ libc.include.stdlib
+ libc.include.string
+ libc.include.strings
+ libc.include.sys_mman
+ libc.include.sys_prctl
+ libc.include.sys_random
+ libc.include.sys_syscall
+ libc.include.sys_uio
+ libc.include.unistd
+ # symbols
+ libc.src.errno.errno
+ libc.src.fcntl.open
+ libc.src.pthread.pthread_key_create
+ libc.src.pthread.pthread_setspecific
+ libc.src.stdlib.abort
+ libc.src.stdlib.atexit
+ libc.src.string.memset
+ libc.src.string.strlen
+ libc.src.sys.mman.madvise
+ libc.src.sys.mman.mmap
+ libc.src.sys.uio.writev
+ libc.src.time.clock_gettime
+ libc.src.unistd.__llvm_libc_syscall
+ libc.src.unistd.close
+ libc.src.unistd.fsync
+ libc.src.unistd.getentropy
+ libc.src.unistd.read
+)
+
+add_entrypoint_object(
+ malloc
+ SRCS
+ malloc.cpp
+ DEPENDS
+ snmalloc
+)
+
+add_entrypoint_object(
+ calloc
+ SRCS
+ calloc.cpp
+ DEPENDS
+ snmalloc
+ ${SNMALLOC_DEPS}
+)
+
+add_entrypoint_object(
+ realloc
+ SRCS
+ realloc.cpp
+ DEPENDS
+ snmalloc
+ ${SNMALLOC_DEPS}
+)
+
+add_entrypoint_object(
+ aligned_alloc
+ SRCS
+ aligned_alloc.cpp
+ DEPENDS
+ snmalloc
+ ${SNMALLOC_DEPS}
+)
+
+add_entrypoint_object(
+ free
+ SRCS
+ free.cpp
+ DEPENDS
+ snmalloc
+ ${SNMALLOC_DEPS}
+)
+
+add_entrypoint_object(
+ mallopt
+ SRCS
+ mallopt.cpp
+ DEPENDS
+ snmalloc
+ ${SNMALLOC_DEPS}
+)
diff --git a/libc/src/stdlib/snmalloc/aligned_alloc.cpp b/libc/src/stdlib/snmalloc/aligned_alloc.cpp
new file mode 100644
index 00000000000000..ee1d74ca9c778c
--- /dev/null
+++ b/libc/src/stdlib/snmalloc/aligned_alloc.cpp
@@ -0,0 +1,17 @@
+//===-- Implementation of aligned_alloc -----------------------------------===//
+//
+// 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/stdlib/aligned_alloc.h"
+#include "snmalloc/snmalloc.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE_DECL {
+LLVM_LIBC_FUNCTION(void *, aligned_alloc, (size_t alignment, size_t size)) {
+ return snmalloc::libc::aligned_alloc(alignment, size);
+}
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/snmalloc/calloc.cpp b/libc/src/stdlib/snmalloc/calloc.cpp
new file mode 100644
index 00000000000000..39af67607bf709
--- /dev/null
+++ b/libc/src/stdlib/snmalloc/calloc.cpp
@@ -0,0 +1,17 @@
+//===-- Implementation of calloc ------------------------------------------===//
+//
+// 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/stdlib/calloc.h"
+#include "snmalloc/snmalloc.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE_DECL {
+LLVM_LIBC_FUNCTION(void *, calloc, (size_t num, size_t size)) {
+ return snmalloc::libc::calloc(num, size);
+}
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/snmalloc/free.cpp b/libc/src/stdlib/snmalloc/free.cpp
new file mode 100644
index 00000000000000..eb403710fffada
--- /dev/null
+++ b/libc/src/stdlib/snmalloc/free.cpp
@@ -0,0 +1,17 @@
+//===-- Implementation of free --------------------------------------------===//
+//
+// 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/stdlib/free.h"
+#include "snmalloc/snmalloc.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE_DECL {
+LLVM_LIBC_FUNCTION(void, free, (void *ptr)) {
+ return snmalloc::libc::free(ptr);
+}
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/snmalloc/malloc.cpp b/libc/src/stdlib/snmalloc/malloc.cpp
new file mode 100644
index 00000000000000..ab58e63743016a
--- /dev/null
+++ b/libc/src/stdlib/snmalloc/malloc.cpp
@@ -0,0 +1,17 @@
+//===-- Implementation of malloc ------------------------------------------===//
+//
+// 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/stdlib/malloc.h"
+#include "snmalloc/snmalloc.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE_DECL {
+LLVM_LIBC_FUNCTION(void *, malloc, (size_t size)) {
+ return snmalloc::libc::malloc(size);
+}
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/snmalloc/mallopt.cpp b/libc/src/stdlib/snmalloc/mallopt.cpp
new file mode 100644
index 00000000000000..c52d68e3d52230
--- /dev/null
+++ b/libc/src/stdlib/snmalloc/mallopt.cpp
@@ -0,0 +1,13 @@
+//===-- Implementation of mallopt stub ------------------------------------===//
+//
+// 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/__support/common.h"
+
+namespace LIBC_NAMESPACE_DECL {
+LLVM_LIBC_FUNCTION(int, mallopt, (int, int)) { return 0; }
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/snmalloc/override.h b/libc/src/stdlib/snmalloc/override.h
new file mode 100644
index 00000000000000..a36a6316790fbd
--- /dev/null
+++ b/libc/src/stdlib/snmalloc/override.h
@@ -0,0 +1,32 @@
+//===-- Macro Override for SnMalloc ---------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// skip special headers
+#define LLVM_LIBC_COMMON_H
+#define LLVM_LIBC_ERRNO_H
+
+// define common macros
+#define __BEGIN_C_DECLS namespace LIBC_NAMESPACE {
+#define __END_C_DECLS \
+ } \
+ using namespace LIBC_NAMESPACE;
+
+#define _Noreturn [[noreturn]]
+#define _Alignas alignas
+#define _Static_assert static_assert
+#define _Alignof alignof
+#define _Thread_local thread_local
+
+// Use empty definition to avoid spec mismatching
+// We are building internally anyway, hence noexcept does not matter here
+#define __NOEXCEPT
+
+// Enforce internal errno implementation
+#include "hdr/errno_macros.h"
+#include "src/errno/libc_errno.h"
+#define errno libc_errno
diff --git a/libc/src/stdlib/snmalloc/realloc.cpp b/libc/src/stdlib/snmalloc/realloc.cpp
new file mode 100644
index 00000000000000..36972e0a2232ec
--- /dev/null
+++ b/libc/src/stdlib/snmalloc/realloc.cpp
@@ -0,0 +1,17 @@
+//===-- Implementation of realloc -----------------------------------------===//
+//
+// 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/stdlib/realloc.h"
+#include "snmalloc/snmalloc.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE_DECL {
+LLVM_LIBC_FUNCTION(void *, realloc, (void *ptr, size_t size)) {
+ return snmalloc::libc::realloc(ptr, size);
+}
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/src/stdlib/CMakeLists.txt b/libc/test/src/stdlib/CMakeLists.txt
index 8cc0428632ba39..2346a8bae08f87 100644
--- a/libc/test/src/stdlib/CMakeLists.txt
+++ b/libc/test/src/stdlib/CMakeLists.txt
@@ -420,7 +420,9 @@ if(LLVM_LIBC_FULL_BUILD)
)
# Only baremetal and GPU has an in-tree 'malloc' implementation.
- if(LIBC_TARGET_OS_IS_BAREMETAL OR LIBC_TARGET_OS_IS_GPU)
+ if(LIBC_TARGET_OS_IS_BAREMETAL
+ OR LIBC_TARGET_OS_IS_GPU
+ OR NOT "${LLVM_LIBC_INCLUDE_SNMALLOC}" STREQUAL "")
add_libc_test(
malloc_test
HERMETIC_TEST_ONLY
``````````
</details>
https://github.com/llvm/llvm-project/pull/122284
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