Reduce code size of mandatory runtime

This change reduces o/tiny/examples/life from 44kb to 24kb in size since
it avoids linking mmap() when unnecessary. This is important, to helping
cosmo not completely lose touch with its roots.

libc/intrin/__getauxval.c

@@ -30,10 +30,8 @@
  */
 struct AuxiliaryValue __getauxval(unsigned long at) {
   unsigned long *ap;
-  for (ap = __auxv; ap[0]; ap += 2) {
-    if (at == ap[0]) {
+  for (ap = __auxv; ap && ap[0]; ap += 2)
+    if (at == ap[0])
       return (struct AuxiliaryValue){ap[1], true};
-    }
-  }
   return (struct AuxiliaryValue){0, false};
 }

libc/intrin/g_fds.c

@@ -143,7 +143,8 @@ textstartup void __init_fds(int argc, char **argv, char **envp) {
           break;
         if (!TokAtoi(&fdspec, &protocol))
           break;
-        __ensurefds_unlocked(fd);
+        if (_weaken(__ensurefds_unlocked))
+          _weaken(__ensurefds_unlocked)(fd);
         struct Fd *f = fds->p + fd;
         if (f->handle && f->handle != -1 && f->handle != handle) {
           CloseHandle(f->handle);

libc/intrin/gettid.c

@@ -40,9 +40,8 @@ int gettid(void) {
   int tid;
   if (VERY_LIKELY(__tls_enabled && !__vforked)) {
     tid = atomic_load_explicit(&__get_tls()->tib_tid, memory_order_acquire);
-    if (VERY_LIKELY(tid > 0)) {
+    if (VERY_LIKELY(tid > 0))
       return tid;
-    }
   }
   if (IsXnuSilicon()) {
     return enosys();  // can only happen if we can't access thread local storage

libc/intrin/maps.c

@@ -31,35 +31,51 @@ __static_yoink("_init_maps");
 
 struct Maps __maps;
 
+void __maps_add(struct Map *map) {
+  dll_init(&map->elem);
+  dll_make_first(&__maps.used, &map->elem);
+  map->next = __maps.maps;
+  __maps.maps = map;
+  ++__maps.count;
+}
+
+static void __maps_adder(struct Map *map, int pagesz) {
+  __maps.pages += ((map->size + pagesz - 1) & -pagesz) / pagesz;
+  __maps_add(map);
+}
+
+void __maps_stack(void *stackaddr, int pagesz, size_t stacksize, int stackprot,
+                  intptr_t stackhand) {
+  __maps.stack.addr = stackaddr;
+  __maps.stack.size = stacksize;
+  __maps.stack.prot = stackprot;
+  __maps.stack.h = stackhand;
+  __maps_adder(&__maps.stack, pagesz);
+}
+
 void __maps_init(void) {
+  int pagesz = getauxval(AT_PAGESZ);
 
   // record _start() stack mapping
   if (!IsWindows()) {
     struct AddrSize stack;
     stack = __get_main_stack();
-    dll_init(&__maps.stack.elem);
-    __maps.stack.addr = stack.addr;
-    __maps.stack.size = stack.size;
-    __maps.stack.prot = (uintptr_t)ape_stack_prot;
-    __maps_insert(&__maps.stack);
+    __maps_stack(stack.addr, pagesz, stack.size, (uintptr_t)ape_stack_prot, 0);
   }
 
   // record .text and .data mappings
   static struct Map text, data;
-  dll_init(&text.elem);
   text.addr = (char *)__executable_start;
   text.size = _etext - __executable_start;
   text.prot = PROT_READ | PROT_EXEC;
-  int pagesz = getauxval(AT_PAGESZ);
   uintptr_t ds = ((uintptr_t)_etext + pagesz - 1) & -pagesz;
   if (ds < (uintptr_t)_end) {
-    dll_init(&data.elem);
     data.addr = (char *)ds;
     data.size = (uintptr_t)_end - ds;
     data.prot = PROT_READ | PROT_WRITE;
-    __maps_insert(&data);
+    __maps_adder(&data, pagesz);
   }
-  __maps_insert(&text);
+  __maps_adder(&text, pagesz);
 }
 
 privileged void __maps_lock(void) {

libc/intrin/maps.h

@@ -43,11 +43,13 @@ void __maps_init(void);
 void __maps_lock(void);
 void __maps_check(void);
 void __maps_unlock(void);
+void __maps_add(struct Map *);
 struct Map *__maps_alloc(void);
 void __maps_free(struct Map *);
 void __maps_insert(struct Map *);
 int __munmap(char *, size_t, bool);
 void *__mmap(char *, size_t, int, int, int, int64_t);
+void __maps_stack(void *, int, size_t, int, intptr_t);
 struct AddrSize __get_main_stack(void);
 
 COSMOPOLITAN_C_END_

libc/intrin/mmap.c

@@ -144,10 +144,7 @@ void __maps_insert(struct Map *map) {
     dll_make_first(&__maps.used, &last->elem);
     __maps_free(map);
   } else {
-    dll_make_first(&__maps.used, &map->elem);
-    map->next = __maps.maps;
-    __maps.maps = map;
-    ++__maps.count;
+    __maps_add(map);
   }
   __maps_check();
 }

libc/intrin/pthreadlock.c

@@ -18,16 +18,12 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/thread/posixthread.internal.h"
 
-pthread_spinlock_t _pthread_lock_obj;
-
-void _pthread_init(void) {
-  (void)pthread_spin_init(&_pthread_lock_obj, 0);
-}
+pthread_mutex_t _pthread_lock_obj = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
 
 void _pthread_lock(void) {
-  pthread_spin_lock(&_pthread_lock_obj);
+  pthread_mutex_lock(&_pthread_lock_obj);
 }
 
 void _pthread_unlock(void) {
-  pthread_spin_unlock(&_pthread_lock_obj);
+  pthread_mutex_unlock(&_pthread_lock_obj);
 }