cosmopolitan/tool/build/lib/demangle.c

95 lines
3.7 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 │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/hefty/spawn.h"
#include "libc/macros.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "tool/build/lib/demangle.h"
struct CxxFilt {
int pid;
int fds[3];
} g_cxxfilt;
void CloseCxxFilt(void) {
close(g_cxxfilt.fds[0]);
close(g_cxxfilt.fds[1]);
g_cxxfilt.pid = -1;
}
void SpawnCxxFilt(void) {
int pid;
char path[PATH_MAX];
if (commandv("c++filt", path)) {
g_cxxfilt.fds[0] = -1;
g_cxxfilt.fds[1] = -1;
g_cxxfilt.fds[2] = 2;
if ((pid = spawnve(0, g_cxxfilt.fds, path, (char *const[]){"c++filt", NULL},
environ)) != -1) {
atexit(CloseCxxFilt);
}
} else {
pid = -1;
}
g_cxxfilt.pid = pid;
}
char *DemangleCxxFilt(char *p, const char *symbol) {
int n;
char buf[512];
bool iscomplicated;
if (!g_cxxfilt.pid) SpawnCxxFilt();
if (g_cxxfilt.pid == -1) return NULL;
if ((n = strlen(symbol)) >= ARRAYLEN(buf)) return NULL;
memcpy(buf, symbol, n);
buf[n] = '\n';
write(g_cxxfilt.fds[0], buf, n + 1);
n = read(g_cxxfilt.fds[1], buf, ARRAYLEN(buf));
if (n > 1 && buf[n - 1] == '\n') {
if (buf[n - 2] == '\r') --n;
--n;
iscomplicated = memchr(buf, ' ', n) || memchr(buf, '(', n);
if (iscomplicated) *p++ = '"';
p = mempcpy(p, buf, n);
if (iscomplicated) *p++ = '"';
*p = '\0';
return p;
} else {
CloseCxxFilt();
return NULL;
}
}
/**
* Decrypts C++ symbol.
*
* Decoding these takes roughly the same lines of code as an entire
* x86_64 disassembler. That's just for the GNU encoding scheme. So
* what we'll do, is just offload this work to the c++filt program.
*/
char *Demangle(char *p, const char *symbol) {
char *r;
if (startswith(symbol, "_Z")) {
if ((r = DemangleCxxFilt(p, symbol))) return r;
}
return stpcpy(p, symbol);
}