Module Name: src
Committed By: christos
Date: Wed Jul 18 22:22:26 UTC 2012
Modified Files:
src/lib/libc/ssp: __builtin_object_size.3
Log Message:
Explain what's going on with fortify being disabled when the optimizer is off:
http://gcc.gnu.org/ml/gcc-patches/2012-06/msg00174.html
To generate a diff of this commit:
cvs rdiff -u -r1.8 -r1.9 src/lib/libc/ssp/__builtin_object_size.3
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libc/ssp/__builtin_object_size.3
diff -u src/lib/libc/ssp/__builtin_object_size.3:1.8 src/lib/libc/ssp/__builtin_object_size.3:1.9
--- src/lib/libc/ssp/__builtin_object_size.3:1.8 Sun Dec 19 04:33:52 2010
+++ src/lib/libc/ssp/__builtin_object_size.3 Wed Jul 18 18:22:26 2012
@@ -1,4 +1,4 @@
-.\" $NetBSD: __builtin_object_size.3,v 1.8 2010/12/19 09:33:52 jruoho Exp $
+.\" $NetBSD: __builtin_object_size.3,v 1.9 2012/07/18 22:22:26 christos Exp $
.\"
.\" Copyright (c) 2007 The NetBSD Foundation, Inc.
.\" All rights reserved.
@@ -28,7 +28,7 @@
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
.\"
-.Dd December 19, 2010
+.Dd July 18, 2012
.Dt __BUILTIN_OBJECT_SIZE 3
.Os
.Sh NAME
@@ -88,3 +88,14 @@ appeared in
.Tn GCC 4.1 .
.Sh CAVEATS
This is a non-standard, compiler-specific extension.
+.Pp
+Note that currently the object size calculation pass is only done at -O1
+or above, meaning that this function always returns -1 when the optimizer
+is off.
+.Pp
+There are some discussions about always doing the object size pass, but
+the issue is that without the optimization pass data sizes are not going
+to be correct.
+.Pp
+For that reason currently code fortification (size-checked replacement
+functions) is disabled when optimization is off.
