Attached is a proposed documentation patch for __attribute__ ((malloc)),
taken from:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56955#c9
Richard Biener suggested that I forward it to this list.
Index: gcc/ChangeLog
===================================================================
--- gcc/ChangeLog (revision 210629)
+++ gcc/ChangeLog (working copy)
@@ -1,3 +1,10 @@
+2014-05-20 Paul Eggert <egg...@cs.ucla.edu>
+
+ PR other/56955
+ * doc/extend.texi (Function Attributes): Fix __attribute__ ((malloc))
+ documentation; the old documentation didn't clearly state the
+ constraints on the contents of the pointed-to storage.
+
2014-05-19 David Wohlferd <d...@limegreensocks.com>
* doc/extend.texi: Create Label Attributes section,
Index: gcc/doc/extend.texi
===================================================================
--- gcc/doc/extend.texi (revision 210629)
+++ gcc/doc/extend.texi (working copy)
@@ -3207,15 +3207,20 @@
@item malloc
@cindex @code{malloc} attribute
-The @code{malloc} attribute is used to tell the compiler that a function
-may be treated as if any non-@code{NULL} pointer it returns cannot
-alias any other pointer valid when the function returns and that the memory
-has undefined content.
-This often improves optimization.
-Standard functions with this property include @code{malloc} and
-@code{calloc}. @code{realloc}-like functions do not have this
-property as the memory pointed to does not have undefined content.
+This tells the compiler that a function is @code{malloc}-like, i.e.,
+that if the function returns a non-null pointer @var{P}, then @var{P}
+cannot alias any other pointer valid when the function returns, and
+moreover the contents of any storage addressed by @var{P} cannot
+contain a pointer that aliases any other pointer valid when the
+function returns.
+Using this attribute often improves optimization. Functions like
+@code{malloc} and @code{calloc} have this property because they return
+a pointer to uninitialized or zeroed-out storage. However, functions
+like @code{realloc} do not have this property, as they can return a
+pointer to storage containing pointers that alias already-valid
+pointers.
+
@item mips16/nomips16
@cindex @code{mips16} attribute
@cindex @code{nomips16} attribute
