Refactor some code

- Write tests for cthreads
- Fix bugs in pe2.com tool
- Fix ASAN issue with GetDosEnviron()
- Consolidate the cthread header files
- Some code size optimizations for MODE=
- Attempted to squash a tls linker warning
- Attempted to get futexes working on FreeBSD

libc/log/backtrace2.c

@@ -0,0 +1,196 @@
+/*-*- 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/alg/alg.h"
+#include "libc/alg/bisectcarleft.internal.h"
+#include "libc/bits/safemacros.internal.h"
+#include "libc/bits/weaken.h"
+#include "libc/calls/calls.h"
+#include "libc/calls/sigbits.h"
+#include "libc/calls/strace.internal.h"
+#include "libc/calls/syscall_support-sysv.internal.h"
+#include "libc/dce.h"
+#include "libc/errno.h"
+#include "libc/fmt/conv.h"
+#include "libc/fmt/fmt.h"
+#include "libc/fmt/itoa.h"
+#include "libc/intrin/kprintf.h"
+#include "libc/log/backtrace.internal.h"
+#include "libc/log/color.internal.h"
+#include "libc/log/log.h"
+#include "libc/nexgen32e/gc.internal.h"
+#include "libc/runtime/gc.internal.h"
+#include "libc/runtime/runtime.h"
+#include "libc/runtime/stack.h"
+#include "libc/runtime/symbols.internal.h"
+#include "libc/stdio/append.internal.h"
+#include "libc/stdio/stdio.h"
+#include "libc/str/str.h"
+#include "libc/sysv/consts/fileno.h"
+#include "libc/sysv/consts/o.h"
+#include "libc/sysv/consts/sig.h"
+#include "libc/x/x.h"
+
+#define kBacktraceMaxFrames 128
+#define kBacktraceBufSize   ((kBacktraceMaxFrames - 1) * (18 + 1))
+
+static void ShowHint(const char *s) {
+  kprintf("%snote: %s%s\n", SUBTLE, s, RESET);
+}
+
+static int PrintBacktraceUsingAddr2line(int fd, const struct StackFrame *bp) {
+  ssize_t got;
+  intptr_t addr;
+  size_t i, j, gi;
+  int ws, pid, pipefds[2];
+  struct Garbages *garbage;
+  const struct StackFrame *frame;
+  char *debugbin, *p1, *p2, *p3, *addr2line;
+  char buf[kBacktraceBufSize], *argv[kBacktraceMaxFrames];
+
+  if (!(debugbin = FindDebugBinary())) {
+    return -1;
+  }
+
+  if (!(addr2line = GetAddr2linePath())) {
+    if (IsLinux()) {
+      ShowHint("can't find addr2line on path or in ADDR2LINE");
+    }
+    return -1;
+  }
+
+  // DWARF is a weak standard. Platforms that use LLVM or old GNU
+  // usually can't be counted upon to print backtraces correctly.
+  if (!IsLinux() && !IsWindows()) {
+    ShowHint("won't print addr2line backtrace because probably llvm");
+    return -1;
+  }
+
+  if (IsWindows()) {
+    // TODO: We need a way to *not* pass //?/C:/... paths to mingw
+    return -1;
+  }
+
+  if (IsLinux() && !__is_linux_2_6_23()) {
+    // we need the `addr2line -a` option
+    return -1;
+  }
+
+  i = 0;
+  j = 0;
+  argv[i++] = "addr2line";
+  argv[i++] = "-a"; /* filter out w/ shell script wrapper for old versions */
+  argv[i++] = "-pCife";
+  argv[i++] = debugbin;
+  garbage = weaken(__garbage);
+  gi = garbage ? garbage->i : 0;
+  for (frame = bp; frame && i < kBacktraceMaxFrames - 1; frame = frame->next) {
+    if (!IsValidStackFramePointer(frame)) {
+      return -1;
+    }
+    addr = frame->addr;
+    if (addr == weakaddr("__gc")) {
+      do {
+        --gi;
+      } while ((addr = garbage->p[gi].ret) == weakaddr("__gc"));
+    }
+    argv[i++] = buf + j;
+    buf[j++] = '0';
+    buf[j++] = 'x';
+    j += uint64toarray_radix16(addr - 1, buf + j) + 1;
+  }
+  argv[i++] = NULL;
+  pipe(pipefds);
+  if (!(pid = vfork())) {
+    dup2(pipefds[1], 1);
+    if (pipefds[0] != 1) close(pipefds[0]);
+    if (pipefds[1] != 1) close(pipefds[1]);
+    execve(addr2line, argv, environ);
+    _exit(127);
+  }
+  close(pipefds[1]);
+  for (;;) {
+    got = read(pipefds[0], buf, kBacktraceBufSize);
+    if (!got) break;
+    if (got == -1 && errno == EINTR) {
+      errno = 0;
+      continue;
+    }
+    if (got == -1) {
+      kprintf("error reading backtrace %m\n");
+      break;
+    }
+    p1 = buf;
+    p3 = p1 + got;
+    /*
+     * remove racist output from gnu tooling, that can't be disabled
+     * otherwise, since it breaks other tools like emacs that aren't
+     * equipped to ignore it, and what's most problematic is that
+     * addr2line somehow manages to put the racism onto the one line
+     * in the backtrace we actually care about.
+     */
+    for (got = p3 - buf, p1 = buf; got;) {
+      if ((p2 = memmem(p1, got, " (discriminator ",
+                       strlen(" (discriminator ") - 1)) &&
+          (p3 = memchr(p2, '\n', got - (p2 - p1)))) {
+        if (p3 > p2 && p3[-1] == '\r') --p3;
+        write(2, p1, p2 - p1);
+        got -= p3 - p1;
+        p1 += p3 - p1;
+      } else {
+        write(2, p1, got);
+        break;
+      }
+    }
+  }
+  close(pipefds[0]);
+  while (waitpid(pid, &ws, 0) == -1) {
+    if (errno == EINTR) continue;
+    return -1;
+  }
+  if (WIFEXITED(ws) && !WEXITSTATUS(ws)) {
+    return 0;
+  } else {
+    return -1;
+  }
+}
+
+static int PrintBacktrace(int fd, const struct StackFrame *bp) {
+  if (!IsTiny() && !__isworker) {
+    if (PrintBacktraceUsingAddr2line(fd, bp) != -1) {
+      return 0;
+    }
+  }
+  return PrintBacktraceUsingSymbols(fd, bp, GetSymbolTable());
+}
+
+void ShowBacktrace(int fd, const struct StackFrame *bp) {
+#ifdef __FNO_OMIT_FRAME_POINTER__
+  /* asan runtime depends on this function */
+  --__ftrace;
+  --__strace;
+  if (!bp) bp = __builtin_frame_address(0);
+  PrintBacktrace(fd, bp);
+  ++__strace;
+  ++__ftrace;
+#else
+  (fprintf)(stderr, "ShowBacktrace() needs these flags to show C backtrace:\n"
+                    "\t-D__FNO_OMIT_FRAME_POINTER__\n"
+                    "\t-fno-omit-frame-pointer\n");
+#endif
+}