diff mbox

malloc/obstack: Merge obstack code back from gnulib

Message ID 5335C826.4080201@cs.ucla.edu
State Superseded
Headers show

Commit Message

Paul Eggert March 28, 2014, 7:06 p.m. UTC
On 03/28/2014 03:53 AM, Will Newton wrote:
> The only change made was to replace _Noreturn with __attribute__ ((__noreturn__)).

It's better to keep the sources identical when possible.  Gnulib uses 
_Noreturn with the C11 meaning, and libc should move in that direction 
too.  Attached is a revised patch to get the ball rolling on that.

Comments

Joseph Myers March 28, 2014, 9:11 p.m. UTC | #1
On Fri, 28 Mar 2014, Paul Eggert wrote:

> On 03/28/2014 03:53 AM, Will Newton wrote:
> > The only change made was to replace _Noreturn with __attribute__
> > ((__noreturn__)).
> 
> It's better to keep the sources identical when possible.  Gnulib uses
> _Noreturn with the C11 meaning, and libc should move in that direction too.
> Attached is a revised patch to get the ball rolling on that.

I don't think we should #define _Noreturn in the case of GCC >= 4.7, when 
it's supported by GCC inside and outside C11 mode.

If we move to using _Noreturn (directly or indirectly via some other 
macro) in installed headers - logically right for supporting generic C11 
compilers, although I don't think many people are likely to be using the 
headers with compilers that don't define __GNUC__ - then there are the 
issues described in 
<https://sourceware.org/ml/libc-alpha/2012-01/msg00084.html> with where it 
can be placed in header declarations without either breaking use of the 
headers with GCC 2.7 or causing such use to lose the information that 
functions don't return.
diff mbox

Patch

>From 261fcf4aa71b3298326077cc1474aabf3081346b Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Fri, 28 Mar 2014 12:00:51 -0700
Subject: [PATCH 2/2] * malloc/obstack.c, malloc/obstack.h: Merge from gnulib.

---
 ChangeLog        |  1 +
 malloc/obstack.c | 71 ++++++++++++++++++++++----------------------------------
 malloc/obstack.h | 62 ++++++++++++++++++++++++++++---------------------
 3 files changed, 65 insertions(+), 69 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 01e607b..0a3e16c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,6 @@ 
 2014-03-28  Paul Eggert  <eggert@cs.ucla.edu>
 
+	* malloc/obstack.c, malloc/obstack.h: Merge from gnulib.
 	* misc/sys/cdefs.h (_Noreturn): New macro, for pre-C11 compilers.
 
 2014-03-27  Paul Pluzhnikov  <ppluzhnikov@google.com>
diff --git a/malloc/obstack.c b/malloc/obstack.c
index 4064f61..598f6aa 100644
--- a/malloc/obstack.c
+++ b/malloc/obstack.c
@@ -17,14 +17,11 @@ 
    <http://www.gnu.org/licenses/>.  */
 
 
-#ifdef HAVE_CONFIG_H
-# include <config.h>
-#endif
-
 #ifdef _LIBC
 # include <obstack.h>
 # include <shlib-compat.h>
 #else
+# include <config.h>
 # include "obstack.h"
 #endif
 
@@ -39,7 +36,7 @@ 
    C Library, but also included in many other GNU distributions.  Compiling
    and linking in this code is a waste when using the GNU C library
    (especially if it is a shared library).  Rather than having every GNU
-   program understand `configure --with-gnu-libc' and omit the object
+   program understand 'configure --with-gnu-libc' and omit the object
    files, it is simpler to just do this in the source for each such file.  */
 
 #include <stdio.h>              /* Random thing to get __GNU_LIBRARY__.  */
@@ -55,12 +52,7 @@ 
 #ifndef ELIDE_CODE
 
 
-# if HAVE_INTTYPES_H
-#  include <inttypes.h>
-# endif
-# if HAVE_STDINT_H || defined _LIBC
-#  include <stdint.h>
-# endif
+# include <stdint.h>
 
 /* Determine default alignment.  */
 union fooround
@@ -85,23 +77,23 @@  enum
 
 /* When we copy a long block of data, this is the unit to do it with.
    On some machines, copying successive ints does not work;
-   in such a case, redefine COPYING_UNIT to `long' (if that works)
-   or `char' as a last resort.  */
+   in such a case, redefine COPYING_UNIT to 'long' (if that works)
+   or 'char' as a last resort.  */
 # ifndef COPYING_UNIT
 #  define COPYING_UNIT int
 # endif
 
 
-/* The functions allocating more room by calling `obstack_chunk_alloc'
-   jump to the handler pointed to by `obstack_alloc_failed_handler'.
+/* The functions allocating more room by calling 'obstack_chunk_alloc'
+   jump to the handler pointed to by 'obstack_alloc_failed_handler'.
    This can be set to a user defined function which should either
    abort gracefully or use longjump - but shouldn't return.  This
    variable by default points to the internal function
-   `print_and_abort'.  */
-static void print_and_abort (void);
+   'print_and_abort'.  */
+static _Noreturn void print_and_abort (void);
 void (*obstack_alloc_failed_handler) (void) = print_and_abort;
 
-/* Exit value used when `print_and_abort' is used.  */
+/* Exit value used when 'print_and_abort' is used.  */
 # include <stdlib.h>
 # ifdef _LIBC
 int obstack_exit_failure = EXIT_FAILURE;
@@ -151,15 +143,15 @@  compat_symbol (libc, _obstack_compat, _obstack, GLIBC_2_0);
 int
 _obstack_begin (struct obstack *h,
                 int size, int alignment,
-                void *(*chunkfun)(long),
-                void (*freefun)(void *))
+                void *(*chunkfun) (long),
+                void (*freefun) (void *))
 {
   struct _obstack_chunk *chunk; /* points to new chunk */
 
   if (alignment == 0)
     alignment = DEFAULT_ALIGNMENT;
   if (size == 0)
-  /* Default size is what GNU malloc can fit in a 4096-byte block.  */
+    /* Default size is what GNU malloc can fit in a 4096-byte block.  */
     {
       /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
          Use the values for range checking, because if range checking is off,
@@ -175,15 +167,15 @@  _obstack_begin (struct obstack *h,
       size = 4096 - extra;
     }
 
-  h->chunkfun = (struct _obstack_chunk * (*)(void *, long))chunkfun;
-  h->freefun = (void (*)(void *, struct _obstack_chunk *))freefun;
+  h->chunkfun = (struct _obstack_chunk * (*) (void *, long)) chunkfun;
+  h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
   h->chunk_size = size;
   h->alignment_mask = alignment - 1;
   h->use_extra_arg = 0;
 
   chunk = h->chunk = CALL_CHUNKFUN (h, h->chunk_size);
   if (!chunk)
-    (*obstack_alloc_failed_handler)();
+    (*obstack_alloc_failed_handler) ();
   h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents,
                                                alignment - 1);
   h->chunk_limit = chunk->limit
@@ -197,8 +189,8 @@  _obstack_begin (struct obstack *h,
 
 int
 _obstack_begin_1 (struct obstack *h, int size, int alignment,
-                  void *(*chunkfun)(void *, long),
-                  void (*freefun)(void *, void *),
+                  void *(*chunkfun) (void *, long),
+                  void (*freefun) (void *, void *),
                   void *arg)
 {
   struct _obstack_chunk *chunk; /* points to new chunk */
@@ -206,7 +198,7 @@  _obstack_begin_1 (struct obstack *h, int size, int alignment,
   if (alignment == 0)
     alignment = DEFAULT_ALIGNMENT;
   if (size == 0)
-  /* Default size is what GNU malloc can fit in a 4096-byte block.  */
+    /* Default size is what GNU malloc can fit in a 4096-byte block.  */
     {
       /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
          Use the values for range checking, because if range checking is off,
@@ -222,8 +214,8 @@  _obstack_begin_1 (struct obstack *h, int size, int alignment,
       size = 4096 - extra;
     }
 
-  h->chunkfun = (struct _obstack_chunk * (*)(void *, long))chunkfun;
-  h->freefun = (void (*)(void *, struct _obstack_chunk *))freefun;
+  h->chunkfun = (struct _obstack_chunk * (*)(void *,long)) chunkfun;
+  h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
   h->chunk_size = size;
   h->alignment_mask = alignment - 1;
   h->extra_arg = arg;
@@ -231,7 +223,7 @@  _obstack_begin_1 (struct obstack *h, int size, int alignment,
 
   chunk = h->chunk = CALL_CHUNKFUN (h, h->chunk_size);
   if (!chunk)
-    (*obstack_alloc_failed_handler)();
+    (*obstack_alloc_failed_handler) ();
   h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents,
                                                alignment - 1);
   h->chunk_limit = chunk->limit
@@ -324,7 +316,7 @@  libc_hidden_def (_obstack_newchunk)
 
 /* Suppress -Wmissing-prototypes warning.  We don't want to declare this in
    obstack.h because it is just for debugging.  */
-int _obstack_allocated_p (struct obstack *h, void *obj);
+int _obstack_allocated_p (struct obstack *h, void *obj) __attribute_pure__;
 
 int
 _obstack_allocated_p (struct obstack *h, void *obj)
@@ -350,7 +342,7 @@  _obstack_allocated_p (struct obstack *h, void *obj)
 # undef obstack_free
 
 void
-obstack_free (struct obstack *h, void *obj)
+__obstack_free (struct obstack *h, void *obj)
 {
   struct _obstack_chunk *lp;    /* below addr of any objects in this chunk */
   struct _obstack_chunk *plp;   /* point to previous chunk if any */
@@ -412,15 +404,7 @@  _obstack_memory_used (struct obstack *h)
 #  include <libio/iolibio.h>
 # endif
 
-# ifndef __attribute__
-/* This feature is available in gcc versions 2.5 and later.  */
-#  if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 5)
-#   define __attribute__(Spec) /* empty */
-#  endif
-# endif
-
-static void
-__attribute__ ((noreturn))
+static _Noreturn void
 print_and_abort (void)
 {
   /* Don't change any of these strings.  Yes, it would be possible to add
@@ -429,10 +413,11 @@  print_and_abort (void)
      like this and the translation should be reused instead of creating
      a very similar string which requires a separate translation.  */
 # ifdef _LIBC
-  (void) __fxprintf (NULL, "%s\n", _ ("memory exhausted"));
+  (void) __fxprintf (NULL, "%s\n", _("memory exhausted"));
 # else
-  fprintf (stderr, "%s\n", _ ("memory exhausted"));
+  fprintf (stderr, "%s\n", _("memory exhausted"));
 # endif
   exit (obstack_exit_failure);
 }
+
 #endif  /* !ELIDE_CODE */
diff --git a/malloc/obstack.h b/malloc/obstack.h
index 85472f9..f92492f 100644
--- a/malloc/obstack.h
+++ b/malloc/obstack.h
@@ -32,11 +32,11 @@ 
    stack is of mature, fixed size and fixed address objects.
 
    These routines grab large chunks of memory, using a function you
-   supply, called `obstack_chunk_alloc'.  On occasion, they free chunks,
-   by calling `obstack_chunk_free'.  You must define them and declare
+   supply, called 'obstack_chunk_alloc'.  On occasion, they free chunks,
+   by calling 'obstack_chunk_free'.  You must define them and declare
    them before using any obstack macros.
 
-   Each independent stack is represented by a `struct obstack'.
+   Each independent stack is represented by a 'struct obstack'.
    Each of the obstack macros expects a pointer to such a structure
    as the first argument.
 
@@ -93,7 +93,7 @@ 
         Exactly one object is growing in an obstack at any one time.
         You can run one obstack per control block.
         You may have as many control blocks as you dare.
-        Because of the way we do it, you can `unwind' an obstack
+        Because of the way we do it, you can "unwind" an obstack
           back to a previous state. (You may remove objects much
           as you would with a stack.)
  */
@@ -104,10 +104,6 @@ 
 #ifndef _OBSTACK_H
 #define _OBSTACK_H 1
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /* We need the type of a pointer subtraction.  If __PTRDIFF_TYPE__ is
    defined, as with GNU C, use that; that way we don't pollute the
    namespace with <stddef.h>'s symbols.  Otherwise, include <stddef.h>
@@ -124,9 +120,9 @@  extern "C" {
    aligning P to the next multiple of A + 1.  B and P must be of type
    char *.  A + 1 must be a power of 2.  */
 
-#define __BPTR_ALIGN(B, P, A) ((B) + (((P) -(B) + (A)) & ~(A)))
+#define __BPTR_ALIGN(B, P, A) ((B) + (((P) - (B) + (A)) & ~(A)))
 
-/* Similiar to _BPTR_ALIGN (B, P, A), except optimize the common case
+/* Similar to _BPTR_ALIGN (B, P, A), except optimize the common case
    where pointers can be converted to integers, aligned as integers,
    and converted back again.  If PTR_INT_TYPE is narrower than a
    pointer (e.g., the AS/400), play it safe and compute the alignment
@@ -139,6 +135,14 @@  extern "C" {
 
 #include <string.h>
 
+#ifndef __attribute_pure__
+# define __attribute_pure__ _GL_ATTRIBUTE_PURE
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct _obstack_chunk           /* Lives at front of each chunk. */
 {
   char *limit;                  /* 1 past end of this chunk */
@@ -159,7 +163,7 @@  struct obstack          /* control current object in current chunk */
     void *tempptr;
   } temp;                       /* Temporary for some macros.  */
   int alignment_mask;           /* Mask of alignment for each object. */
-  /* These prototypes vary based on `use_extra_arg', and we use
+  /* These prototypes vary based on 'use_extra_arg', and we use
      casts to the prototypeless function type in all assignments,
      but having prototypes here quiets -Wstrict-prototypes.  */
   struct _obstack_chunk *(*chunkfun) (void *, long);
@@ -183,18 +187,23 @@  extern int _obstack_begin (struct obstack *, int, int,
 extern int _obstack_begin_1 (struct obstack *, int, int,
                              void *(*)(void *, long),
                              void (*)(void *, void *), void *);
-extern int _obstack_memory_used (struct obstack *);
+extern int _obstack_memory_used (struct obstack *) __attribute_pure__;
 
-void obstack_free (struct obstack *__obstack, void *__glibc_block);
+/* The default name of the function for freeing a chunk is 'obstack_free',
+   but gnulib users can override this by defining '__obstack_free'.  */
+#ifndef __obstack_free
+# define __obstack_free obstack_free
+#endif
+extern void __obstack_free (struct obstack *, void *);
 
 
-/* Error handler called when `obstack_chunk_alloc' failed to allocate
+/* Error handler called when 'obstack_chunk_alloc' failed to allocate
    more memory.  This can be set to a user defined function which
    should either abort gracefully or use longjump - but shouldn't
    return.  The default action is to print a message and abort.  */
 extern void (*obstack_alloc_failed_handler) (void);
 
-/* Exit value used when `print_and_abort' is used.  */
+/* Exit value used when 'print_and_abort' is used.  */
 extern int obstack_exit_failure;
 
 /* Pointer to beginning of object being allocated or to be allocated next.
@@ -249,17 +258,14 @@  extern int obstack_exit_failure;
 #define obstack_memory_used(h) _obstack_memory_used (h)
 
 #if defined __GNUC__
-/* NextStep 2.0 cc is really gcc 1.93 but it defines __GNUC__ = 2 and
-   does not implement __extension__.  But that compiler doesn't define
-   __GNUC_MINOR__.  */
-# if __GNUC__ < 2 || (__NeXT__ && !__GNUC_MINOR__)
+# if ! (2 < __GNUC__ + (8 <= __GNUC_MINOR__))
 #  define __extension__
 # endif
 
 /* For GNU C, if not -traditional,
    we can define these macros to compute all args only once
    without using a global variable.
-   Also, we can avoid using the `temp' slot, to make faster code.  */
+   Also, we can avoid using the 'temp' slot, to make faster code.  */
 
 # define obstack_object_size(OBSTACK)					      \
   __extension__								      \
@@ -337,14 +343,16 @@  extern int obstack_exit_failure;
 # define obstack_ptr_grow_fast(OBSTACK, aptr)				      \
   __extension__								      \
     ({ struct obstack *__o1 = (OBSTACK);				      \
-       *(const void **) __o1->next_free = (aptr);			      \
+       void *__p1 = __o1->next_free;					      \
+       *(const void **) __p1 = (aptr);					      \
        __o1->next_free += sizeof (const void *);			      \
        (void) 0; })
 
 # define obstack_int_grow_fast(OBSTACK, aint)				      \
   __extension__								      \
     ({ struct obstack *__o1 = (OBSTACK);				      \
-       *(int *) __o1->next_free = (aint);				      \
+       void *__p1 = __o1->next_free;					      \
+       *(int *) __p1 = (aint);						      \
        __o1->next_free += sizeof (int);					      \
        (void) 0; })
 
@@ -398,7 +406,7 @@  extern int obstack_exit_failure;
        void *__obj = (OBJ);						      \
        if (__obj > (void *) __o->chunk && __obj < (void *) __o->chunk_limit)  \
          __o->next_free = __o->object_base = (char *) __obj;		      \
-       else (obstack_free) (__o, __obj); })
+       else (__obstack_free) (__o, __obj); })
 
 #else /* not __GNUC__ */
 
@@ -494,12 +502,14 @@  extern int obstack_exit_failure;
   ((h)->temp.tempint = (char *) (obj) - (char *) (h)->chunk,		      \
    ((((h)->temp.tempint > 0						      \
       && (h)->temp.tempint < (h)->chunk_limit - (char *) (h)->chunk))	      \
-   ? (((h)->next_free = (h)->object_base				      \
-                          = (h)->temp.tempint + (char *) (h)->chunk), 0)      \
-   : ((obstack_free) ((h), (h)->temp.tempint + (char *) (h)->chunk), 0)))
+    ? (void) ((h)->next_free = (h)->object_base				      \
+                          = (h)->temp.tempint + (char *) (h)->chunk)	      \
+    : (__obstack_free) (h, (h)->temp.tempint + (char *) (h)->chunk)))
+
 #endif /* not __GNUC__ */
 
 #ifdef __cplusplus
 }       /* C++ */
 #endif
+
 #endif /* obstack.h */
-- 
1.9.0