From: Trevor Saunders <tbsaunde+...@tbsaunde.org>
There's two groups of changes here, first taking a sbitmap &, so that we
can assign null to the pointer after freeing the sbitmap to prevent use
after free through that pointer. Second we define overloads of
sbitmap_free and bitmap_free taking auto_sbitmap and auto_bitmap
respectively, so that you can't double free the bitmap owned by a
auto_{s,}bitmap.
gcc/ChangeLog:
2017-05-09 Trevor Saunders <tbsaunde+...@tbsaunde.org>
* bitmap.h (BITMAP_FREE): Convert from macro to inline function
and add overloaded decl for auto_bitmap.
* sbitmap.h (inline void sbitmap_free): Add overload for
auto_sbitmap, and change sbitmap to point to null.
---
gcc/bitmap.h | 21 +++++++++++++++++++--
gcc/sbitmap.h | 7 ++++++-
2 files changed, 25 insertions(+), 3 deletions(-)
diff --git a/gcc/bitmap.h b/gcc/bitmap.h
index f158b447357..7508239cff9 100644
--- a/gcc/bitmap.h
+++ b/gcc/bitmap.h
@@ -129,6 +129,8 @@ along with GCC; see the file COPYING3. If not see
#include "obstack.h"
+ class auto_bitmap;
+
/* Bitmap memory usage. */
struct bitmap_usage: public mem_usage
{
@@ -372,8 +374,23 @@ extern hashval_t bitmap_hash (const_bitmap);
#define BITMAP_GGC_ALLOC() bitmap_gc_alloc ()
/* Do any cleanup needed on a bitmap when it is no longer used. */
-#define BITMAP_FREE(BITMAP) \
- ((void) (bitmap_obstack_free ((bitmap) BITMAP), (BITMAP) = (bitmap)
NULL))
+inline void
+BITMAP_FREE (bitmap &b)
+{
+ bitmap_obstack_free ((bitmap) b);
+ b = NULL;
+}
+
+inline void
+BITMAP_FREE (void *&b)
+{
+ bitmap_obstack_free ((bitmap) b);
+ b = NULL;
+}
+
+/* Intentionally unimplemented to ensure it is never called with an
+ auto_bitmap argument. */
+void BITMAP_FREE (auto_bitmap);
/* Iterator for bitmaps. */
diff --git a/gcc/sbitmap.h b/gcc/sbitmap.h
index ce4d27d927c..cba0452cdb9 100644
--- a/gcc/sbitmap.h
+++ b/gcc/sbitmap.h
@@ -82,6 +82,8 @@ along with GCC; see the file COPYING3. If not see
#define SBITMAP_ELT_BITS (HOST_BITS_PER_WIDEST_FAST_INT * 1u)
#define SBITMAP_ELT_TYPE unsigned HOST_WIDEST_FAST_INT
+class auto_sbitmap;
+
struct simple_bitmap_def
{
unsigned int n_bits; /* Number of bits. */
@@ -208,11 +210,14 @@ bmp_iter_next (sbitmap_iterator *i, unsigned *bit_no
ATTRIBUTE_UNUSED)
bmp_iter_next (&(ITER), &(BITNUM)))
#endif
-inline void sbitmap_free (sbitmap map)
+inline void sbitmap_free (sbitmap &map)
{
free (map);
+ map = NULL;
}
+void sbitmap_free (auto_sbitmap);
+
inline void sbitmap_vector_free (sbitmap * vec)
{
free (vec);
--
2.11.0
