cosmopolitan/tool/build/lib/elfwriter_yoink.c
Justine Tunney 0c630d95b5
Rewrite Cosmopolitan Ar
The build/bootstrap/ar.com program is now tinier. This change reduces
its size from 140kb to 53kb. Nothing was traded away. Cosmopolitan Ar
performance is now 2x better than llvm-ar largely thanks to using the
copy_file_range() system call. This change homebrews a new allocation
API that addresses the shortcomings of the C standard library design.
Using these new balloc() and reballoc() functions I managed to reduce
memory consumption so much that Cosmpolitan Ar should now use roughly
100x fewer bytes of peak resident memory compared to llvm-ar. Correct
behavior with better compatibility has been assured. Binary output is
now pretty much bit-identical to llvm-ar, as of this change. This can
and should be the living proof we need to show that a better world is
possible for software.
2023-07-02 10:19:16 -07:00

34 lines
2.4 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/elf/def.h"
#include "libc/str/str.h"
#include "tool/build/lib/elfwriter.h"
void elfwriter_yoink(struct ElfWriter *elf, const char *symbol, int stb) {
unsigned char *p;
struct ElfWriterSymRef sym;
const unsigned char kNopl[8] = "\017\037\004\045\000\000\000\000";
p = elfwriter_reserve(elf, 8);
memcpy(p, kNopl, sizeof(kNopl));
sym = elfwriter_linksym(elf, symbol, ELF64_ST_INFO(stb, STT_OBJECT),
STV_HIDDEN);
elfwriter_appendrela(elf, sizeof(kNopl) - 4, sym,
elfwriter_relatype_abs32(elf), 0);
elfwriter_commit(elf, sizeof(kNopl));
}