More merge-related tweaks

* add --enable-experimental-malloc/--disable-experimental-malloc
  (default: enabled)

* syntax errors related to new lock macros

* add some missing #if USE_TCACHE pairs

* Undo test tweak to environment variable scanner

3 files changed, 14 insertions, 13 deletions

diff --git a/malloc/Makefile b/malloc/Makefile
index f34c2a75ba..2b0c3da501 100644
--- a/malloc/Makefile
+++ b/malloc/Makefile
@@ -76,10 +76,6 @@ $(objpfx)trace_run: $(objpfx)trace_run.o
 $(objpfx)trace_dump: $(objpfx)trace_dump.o
 	$(LINK.o) -o $@ $(objpfx)trace_dump.o
 
-ifeq (${CXX},)
-CXX = g++
-endif
-
 $(objpfx)trace2wl: $(objpfx)trace2wl.o
 	$(LINK.o) -o $@ $(objpfx)trace2wl.o
 
@@ -88,6 +84,10 @@ $(objpfx)tst-malloc-thread-exit: $(shared-thread-library)
 $(objpfx)tst-malloc-thread-fail: $(shared-thread-library)
 $(objpfx)tst-malloc-fork-deadlock: $(shared-thread-library)
 
+ifeq ($(experimental-malloc),yes)
+CPPFLAGS-malloc.c += -DUSE_TCACHE
+endif
+
 # Export the __malloc_initialize_hook variable to libc.so.
 LDFLAGS-tst-mallocstate = -rdynamic
 
diff --git a/malloc/arena.c b/malloc/arena.c
index ada1a7245e..0a86da6513 100644
--- a/malloc/arena.c
+++ b/malloc/arena.c
@@ -229,10 +229,11 @@ next_env_entry (char ***position)
 
           /* Save current position for next visit.  */
           *position = ++current;
+
           break;
         }
 
-      *position = ++current;
+      ++current;
     }
 
   return result;
@@ -277,9 +278,7 @@ ptmalloc_init (void)
       char **runp = _environ;
       char *envline;
 
-      while (*runp)
-	{
-	  if (__builtin_expect ((envline = next_env_entry (&runp)) != NULL,
+      while (__builtin_expect ((envline = next_env_entry (&runp)) != NULL,
                                0))
         {
           size_t len = strcspn (envline, "=");
@@ -320,12 +319,15 @@ ptmalloc_init (void)
                   if (memcmp (envline, "ARENA_TEST", 10) == 0)
                     __libc_mallopt (M_ARENA_TEST, atoi (&envline[11]));
                 }
+#if USE_TCACHE
               if (!__builtin_expect (__libc_enable_secure, 0))
                 {
                   if (memcmp (envline, "TCACHE_MAX", 10) == 0)
                     __libc_mallopt (M_TCACHE_MAX, atoi (&envline[11]));
                 }
+#endif
               break;
+#if USE_TCACHE
             case 12:
               if (!__builtin_expect (__libc_enable_secure, 0))
                 {
@@ -333,6 +335,7 @@ ptmalloc_init (void)
                     __libc_mallopt (M_TCACHE_COUNT, atoi (&envline[13]));
                 }
 	      break;
+#endif
             case 15:
               if (!__builtin_expect (__libc_enable_secure, 0))
                 {
@@ -346,7 +349,6 @@ ptmalloc_init (void)
               break;
             }
         }
-	}
     }
   if (s && s[0])
     {
diff --git a/malloc/malloc.c b/malloc/malloc.c
index bd8a1d4bb8..0eabcd8430 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -1068,7 +1068,7 @@ typedef struct __malloc_trace_map_entry_s {
 #define TRACE_COUNT_TO_MAPPING_IDX(count) ((count) % TRACE_N_PER_MAPPING)
 
 /* Global mutex for the trace buffer tree itself.  */
-libc_lock_define_initialized (static, __malloc_trace_mutex);
+__libc_lock_define_initialized (static, __malloc_trace_mutex);
 
 /* Global counter, "full" when equal to TRACE_MAX_COUNT.  Points to
    the next available slot, so POST-INCREMENT it.  */
@@ -3358,7 +3358,7 @@ tcache_thread_freeres (void)
 {
   if (tcache.initted == 1)
     {
-      libc_lock_lock (tcache_mutex);
+      __libc_lock_lock (tcache_mutex);
       tcache.initted = 2;
       if (tcache.next)
 	tcache.next->prev = tcache.prev;
@@ -3366,7 +3366,7 @@ tcache_thread_freeres (void)
 	tcache.prev->next = tcache.next;
       else
 	tcache_list = tcache.next;
-      libc_lock_unlock (tcache_mutex);
+      __libc_lock_unlock (tcache_mutex);
     }
 }
 text_set_element (__libc_thread_subfreeres, tcache_thread_freeres);
@@ -4206,7 +4206,6 @@ _int_malloc (mstate av, size_t bytes)
 
   if ((unsigned long) (nb) <= (unsigned long) (get_max_fast ()))
     {
-
       idx = fastbin_index (nb);
       mfastbinptr *fb = &fastbin (av, idx);
       mchunkptr pp = *fb;