8b2c2a596d
Summary: Add support for C++17 over-aligned allocation: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0035r4.html Supporting all 10 operators means we avoid thunking thru libstdc++-v3/libsupc++ and just call jemalloc directly. It's also worth noting that there is now an aligned *and sized* operator delete: ``` void operator delete(void* ptr, std::size_t size, std::align_val_t al) noexcept; ``` If JeMalloc did not provide this, the default implementation would ignore the size parameter entirely: https://github.com/gcc-mirror/gcc/blob/master/libstdc%2B%2B-v3/libsupc%2B%2B/del_opsa.cc#L30-L33 (I must also update ax_cxx_compile_stdcxx.m4 to a newer version with C++17 support.) Test Plan: Wrote a simple test that allocates and then deletes an over-aligned type: ``` struct alignas(32) Foo {}; Foo *f; int main() { f = new Foo; delete f; } ``` Before this change, both new and delete go thru PLT, and we end up calling regular old free: ``` (gdb) disassemble Dump of assembler code for function main(): ... 0x00000000004029b7 <+55>: call 0x4022d0 <_ZnwmSt11align_val_t@plt> ... 0x00000000004029d5 <+85>: call 0x4022e0 <_ZdlPvmSt11align_val_t@plt> ... (gdb) s free (ptr=0x7ffff6408020) at /home/engshare/third-party2/jemalloc/master/src/jemalloc.git-trunk/src/jemalloc.c:2842 2842 if (!free_fastpath(ptr, 0, false)) { ``` After this change, we directly call new/delete and ultimately call sdallocx: ``` (gdb) disassemble Dump of assembler code for function main(): ... 0x0000000000402b77 <+55>: call 0x496ca0 <operator new(unsigned long, std::align_val_t)> ... 0x0000000000402b95 <+85>: call 0x496e60 <operator delete(void*, unsigned long, std::align_val_t)> ... (gdb) s 116 je_sdallocx_noflags(ptr, size); ```
96 lines
2.2 KiB
C
96 lines
2.2 KiB
C
#ifndef JEMALLOC_INTERNAL_DECLS_H
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#define JEMALLOC_INTERNAL_DECLS_H
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#include <math.h>
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#ifdef _WIN32
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# include <windows.h>
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# include "msvc_compat/windows_extra.h"
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# include "msvc_compat/strings.h"
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# ifdef _WIN64
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# if LG_VADDR <= 32
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# error Generate the headers using x64 vcargs
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# endif
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# else
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# if LG_VADDR > 32
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# undef LG_VADDR
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# define LG_VADDR 32
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# endif
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# endif
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#else
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# include <sys/param.h>
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# include <sys/mman.h>
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# if !defined(__pnacl__) && !defined(__native_client__)
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# include <sys/syscall.h>
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# if !defined(SYS_write) && defined(__NR_write)
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# define SYS_write __NR_write
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# endif
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# if defined(SYS_open) && defined(__aarch64__)
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/* Android headers may define SYS_open to __NR_open even though
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* __NR_open may not exist on AArch64 (superseded by __NR_openat). */
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# undef SYS_open
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# endif
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# include <sys/uio.h>
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# endif
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# include <pthread.h>
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# ifdef __FreeBSD__
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# include <pthread_np.h>
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# endif
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# include <signal.h>
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# ifdef JEMALLOC_OS_UNFAIR_LOCK
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# include <os/lock.h>
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# endif
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# ifdef JEMALLOC_GLIBC_MALLOC_HOOK
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# include <sched.h>
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# endif
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# include <errno.h>
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# include <sys/time.h>
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# include <time.h>
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# ifdef JEMALLOC_HAVE_MACH_ABSOLUTE_TIME
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# include <mach/mach_time.h>
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# endif
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#endif
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#include <sys/types.h>
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#include <limits.h>
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#ifndef SIZE_T_MAX
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# define SIZE_T_MAX SIZE_MAX
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#endif
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#ifndef SSIZE_MAX
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# define SSIZE_MAX ((ssize_t)(SIZE_T_MAX >> 1))
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#endif
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#include <stdarg.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <stddef.h>
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#ifndef offsetof
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# define offsetof(type, member) ((size_t)&(((type *)NULL)->member))
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#endif
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#include <string.h>
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#include <strings.h>
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#include <ctype.h>
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#ifdef _MSC_VER
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# include <io.h>
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typedef intptr_t ssize_t;
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# define PATH_MAX 1024
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# define STDERR_FILENO 2
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# define __func__ __FUNCTION__
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# ifdef JEMALLOC_HAS_RESTRICT
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# define restrict __restrict
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# endif
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/* Disable warnings about deprecated system functions. */
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# pragma warning(disable: 4996)
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#if _MSC_VER < 1800
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static int
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isblank(int c) {
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return (c == '\t' || c == ' ');
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}
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#endif
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#else
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# include <unistd.h>
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#endif
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#include <fcntl.h>
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#endif /* JEMALLOC_INTERNAL_H */
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