[v5,7/8] Remove __after_morecore_hook

Message ID 20210705170814.4132997-8-siddhesh@sourceware.org
State Superseded
Headers show
Series
  • malloc hooks removal
Related show

Commit Message

Adhemerval Zanella via Libc-alpha July 5, 2021, 5:08 p.m.
Remove __after_morecore_hook from the API and finalize the symbol so
that it can no longer be used in new applications.  Old applications
using __after_morecore_hook will find that their hook is no longer
called.
---
 malloc/hooks.c  |  7 +++++++
 malloc/malloc.c | 30 +-----------------------------
 malloc/malloc.h |  5 -----
 3 files changed, 8 insertions(+), 34 deletions(-)

-- 
2.31.1

Patch

diff --git a/malloc/hooks.c b/malloc/hooks.c
index ffaf3a645a..50ea03b562 100644
--- a/malloc/hooks.c
+++ b/malloc/hooks.c
@@ -24,6 +24,10 @@  compat_symbol (libc, __malloc_initialize_hook,
 #endif
 
 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_34)
+# ifndef weak_variable
+#  define weak_variable weak_function
+# endif
+
 static void *malloc_hook_ini (size_t, const void *) __THROW;
 static void *realloc_hook_ini (void *, size_t, const void *) __THROW;
 static void *memalign_hook_ini (size_t, size_t, const void *) __THROW;
@@ -40,6 +44,9 @@  void *weak_variable (*__memalign_hook)
   (size_t, size_t, const void *) = memalign_hook_ini;
 compat_symbol (libc, __memalign_hook, __memalign_hook, GLIBC_2_0);
 
+void weak_variable (*__after_morecore_hook) (void) = NULL;
+compat_symbol (libc, __after_morecore_hook, __after_morecore_hook, GLIBC_2_0);
+
 /* This is interposed by libc_malloc_debug.so to match with a compatible libc.
    We don't use dlsym or equivalent because the dlsym symbol version got bumped
    in 2.34 and is hence unusable in libc_malloc_debug.so.  */
diff --git a/malloc/malloc.c b/malloc/malloc.c
index 1c1e1ab60b..00fcc676a0 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -1988,16 +1988,6 @@  static void     malloc_consolidate (mstate);
 
 /* -------------- Early definitions for debugging hooks ---------------- */
 
-/* Define and initialize the hook variables.  These weak definitions must
-   appear before any use of the variables in a function (arena.c uses one).  */
-#ifndef weak_variable
-/* In GNU libc we want the hook variables to be weak definitions to
-   avoid a problem with Emacs.  */
-# define weak_variable weak_function
-#endif
-
-void weak_variable (*__after_morecore_hook) (void) = NULL;
-
 /* This function is called from the arena shutdown hook, to free the
    thread cache (if it exists).  */
 static void tcache_thread_shutdown (void);
@@ -2623,14 +2613,7 @@  sysmalloc (INTERNAL_SIZE_T nb, mstate av)
           LIBC_PROBE (memory_sbrk_more, 2, brk, size);
         }
 
-      if (brk != (char *) (MORECORE_FAILURE))
-        {
-          /* Call the `morecore' hook if necessary.  */
-          void (*hook) (void) = atomic_forced_read (__after_morecore_hook);
-          if (__builtin_expect (hook != NULL, 0))
-            (*hook)();
-        }
-      else
+      if (brk == (char *) (MORECORE_FAILURE))
         {
           /*
              If have mmap, try using it as a backup when MORECORE fails or
@@ -2769,13 +2752,6 @@  sysmalloc (INTERNAL_SIZE_T nb, mstate av)
                       correction = 0;
                       snd_brk = (char *) (MORECORE (0));
                     }
-                  else
-                    {
-                      /* Call the `morecore' hook if necessary.  */
-                      void (*hook) (void) = atomic_forced_read (__after_morecore_hook);
-                      if (__builtin_expect (hook != NULL, 0))
-                        (*hook)();
-                    }
                 }
 
               /* handle non-contiguous cases */
@@ -2934,10 +2910,6 @@  systrim (size_t pad, mstate av)
        */
 
       MORECORE (-extra);
-      /* Call the `morecore' hook if necessary.  */
-      void (*hook) (void) = atomic_forced_read (__after_morecore_hook);
-      if (__builtin_expect (hook != NULL, 0))
-        (*hook)();
       new_brk = (char *) (MORECORE (0));
 
       LIBC_PROBE (memory_sbrk_less, 2, new_brk, extra);
diff --git a/malloc/malloc.h b/malloc/malloc.h
index 709fa454b5..d066a05d82 100644
--- a/malloc/malloc.h
+++ b/malloc/malloc.h
@@ -164,10 +164,5 @@  extern void malloc_stats (void) __THROW;
 /* Output information about state of allocator to stream FP.  */
 extern int malloc_info (int __options, FILE *__fp) __THROW;
 
-/* Hooks for debugging and user-defined versions. */
-extern void (*__MALLOC_HOOK_VOLATILE __after_morecore_hook) (void)
-  __MALLOC_DEPRECATED;
-
-
 __END_DECLS
 #endif /* malloc.h */