Introduce support for GGJT v3 file format

llama.com can now load weights that use the new file format which was
introduced a few weeks ago. Note that, unlike llama.cpp, we will keep
support for old file formats in our tool so you don't need to convert
your weights when the upstream project makes breaking changes. Please
note that using ggjt v3 does make avx2 inference go 5% faster for me.

libc/log/log.h

@@ -43,6 +43,7 @@ const char *commandvenv(const char *, const char *);
 const char *GetAddr2linePath(void);
 const char *GetGdbPath(void);
 void ShowCrashReports(void);
+int MakeProcessNice(void);
 bool32 IsDebuggerPresent(bool);
 bool IsRunningUnderMake(void);
 const char *GetSiCodeName(int, int);

libc/log/makeprocessnice.c

@@ -0,0 +1,41 @@
+/*-*- 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 2023 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/calls/calls.h"
+#include "libc/calls/struct/sched_param.h"
+#include "libc/errno.h"
+#include "libc/log/log.h"
+#include "libc/sysv/consts/ioprio.h"
+#include "libc/sysv/consts/prio.h"
+#include "libc/sysv/consts/sched.h"
+
+/**
+ * Makes current process as low-priority as possible.
+ *
+ * @return 0 on success, or -1 w/ errno
+ * @note error reporting currently not implemented
+ */
+int MakeProcessNice(void) {
+  int e = errno;
+  setpriority(PRIO_PROCESS, 0, 10);
+  ioprio_set(IOPRIO_WHO_PROCESS, 0, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
+  struct sched_param param = {sched_get_priority_min(SCHED_IDLE)};
+  sched_setscheduler(0, SCHED_IDLE, &param);
+  errno = e;
+  return 0;
+}

libc/log/oncrash_arm64.c

@@ -230,7 +230,7 @@ relegated void __oncrash_arm64(int sig, struct siginfo *si, void *arg) {
       // simply examining the program counter.
       pc = ctx->uc_mcontext.pc;
       Append(b, " %016lx sp %lx pc", ctx->uc_mcontext.sp, pc);
-      if (pc && (symbol = __get_symbol(st, pc))) {
+      if (pc && st && (symbol = __get_symbol(st, pc))) {
         addend = pc - st->addr_base;
         addend -= st->symbols[symbol].x;
         Append(b, " ");
@@ -251,7 +251,7 @@ relegated void __oncrash_arm64(int sig, struct siginfo *si, void *arg) {
       fp = (struct StackFrame *)ctx->uc_mcontext.regs[29];
       if (IsCode((pc = ctx->uc_mcontext.regs[30]))) {
         Append(b, " %016lx sp %lx lr", ctx->uc_mcontext.sp, pc);
-        if (pc && (symbol = __get_symbol(st, pc))) {
+        if (pc && st && (symbol = __get_symbol(st, pc))) {
           addend = pc - st->addr_base;
           addend -= st->symbols[symbol].x;
           Append(b, " ");
@@ -282,7 +282,7 @@ relegated void __oncrash_arm64(int sig, struct siginfo *si, void *arg) {
           Append(b, " <truncated backtrace>\n");
           break;
         }
-        if ((pc = fp->addr)) {
+        if (st && (pc = fp->addr)) {
           if ((symbol = __get_symbol(st, pc))) {
             addend = pc - st->addr_base;
             addend -= st->symbols[symbol].x;
@@ -294,7 +294,7 @@ relegated void __oncrash_arm64(int sig, struct siginfo *si, void *arg) {
           addend = 0;
         }
         Append(b, " %016lx fp %lx lr ", fp, pc);
-        if (!AppendFileLine(b, addr2line, debugbin, pc)) {
+        if (!AppendFileLine(b, addr2line, debugbin, pc) && st) {
           Append(b, "%s", __get_symbol_name(st, symbol));
           if (addend) Append(b, "%+d", addend);
         }

libc/runtime/finddebugbinary.c

@@ -16,12 +16,69 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "ape/sections.internal.h"
 #include "libc/calls/calls.h"
+#include "libc/elf/def.h"
+#include "libc/elf/elf.h"
+#include "libc/elf/struct/ehdr.h"
+#include "libc/elf/struct/sym.h"
+#include "libc/errno.h"
 #include "libc/intrin/bits.h"
 #include "libc/macros.internal.h"
 #include "libc/runtime/runtime.h"
 #include "libc/runtime/symbols.internal.h"
 #include "libc/str/str.h"
+#include "libc/sysv/consts/map.h"
+#include "libc/sysv/consts/o.h"
+#include "libc/sysv/consts/prot.h"
+
+static bool GetElfSymbolValue(const Elf64_Ehdr *ehdr, size_t esize,
+                              const char *name, uint64_t *res) {
+  Elf64_Xword i, n;
+  const char *stab;
+  const Elf64_Sym *st;
+  if ((stab = GetElfStringTable(ehdr, esize)) &&
+      (st = GetElfSymbolTable(ehdr, esize, &n))) {
+    for (i = 0; i < n; ++i) {
+      if (!strcmp(stab + st[i].st_name, name)) {
+        *res = st[i].st_value;
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+static bool IsMyDebugBinaryImpl(const char *path) {
+  int fd;
+  void *map;
+  int64_t size;
+  uintptr_t value;
+  bool res = false;
+  if ((fd = open(path, O_RDONLY | O_CLOEXEC, 0)) != -1) {
+    // sanity test that this .com.dbg file (1) is an elf image, and (2)
+    // contains the same number of bytes of code as our .com executable
+    // which is currently running in memory.
+    if ((size = lseek(fd, 0, SEEK_END)) != -1 &&
+        (map = mmap(0, size, PROT_READ, MAP_SHARED, fd, 0)) != MAP_FAILED) {
+      if (GetElfSymbolValue(map, size, "_etext", &value)) {
+        res = !_etext || value == (uintptr_t)_etext;
+      }
+      munmap(map, size);
+    }
+    close(fd);
+  }
+  return res;
+}
+
+static bool IsMyDebugBinary(const char *path) {
+  int e;
+  bool res;
+  e = errno;
+  res = IsMyDebugBinaryImpl(path);
+  errno = e;
+  return res;
+}
 
 /**
  * Returns path of binary with the debug information, or null.
@@ -42,12 +99,12 @@ const char *FindDebugBinary(void) {
     } else if (n > 4 && READ32LE(p + n - 4) == READ32LE(".com") &&
                n + 4 < ARRAYLEN(buf)) {
       mempcpy(mempcpy(buf, p, n), ".dbg", 5);
-      if (fileexists(buf)) {
+      if (IsMyDebugBinary(buf)) {
         res = buf;
       }
     } else if (n + 8 < ARRAYLEN(buf)) {
       mempcpy(mempcpy(buf, p, n), ".com.dbg", 9);
-      if (fileexists(buf)) {
+      if (IsMyDebugBinary(buf)) {
         res = buf;
       }
     }