mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-07-03 17:58:30 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Rewrite Cosmopolitan Ar

Browse source 
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.
This commit is contained in:
Justine Tunney 2023-07-02 10:19:16 -07:00
parent 197aa0d465
commit 0c630d95b5
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
27 changed files with 916 additions and 341 deletions
Download patch file Download diff file Expand all files Collapse all files

58
libc/elf/getelfsymbols.c Normal file
View file

@ -0,0 +1,58 @@
/*-*- 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/elf.h"
#include "libc/elf/scalar.h"
#include "libc/elf/struct/ehdr.h"
#include "libc/elf/struct/sym.h"
/**
* Returns pointer to array of elf symbols.
*
* This is a shortcut composing GetElfSymbolTable() and
* GetElfSectionAddress(), that can be used as follows:
*
* Elf64_Xword i, n;
* Elf64_Sym *st = GetElfSymbols(map, size, SHT_SYMTAB, &n);
* for (i = 0; st && i < n; ++i) {
* // st[i] holds a symbol
* }
*
* The above code will iterate over the relocatable and/or
* statically-linked symbols defined by an ELF image.
*
* @param elf points to the start of the executable image data
* @param mapsize is the number of bytes past `elf` we can access
* @param section_type is usually `SHT_SYMTAB` or `SHT_DYNSYM`
* @param out_count optionally receives number of symbols
* @return pointer to array of elf symbol array, otherwise null
*/
Elf64_Sym *GetElfSymbols(const Elf64_Ehdr *elf, //
size_t mapsize, //
int section_type, //
Elf64_Xword *out_count) {
Elf64_Sym *syms;
Elf64_Xword count;
if ((syms = GetElfSectionAddress(
elf, mapsize,
GetElfSymbolTable(elf, mapsize, section_type, &count))) &&
out_count) {
*out_count = count;
}
return syms;
}