[augeas/f14/master] Release 0.7.3-2

[Matthew Booth]

commit e48764dc685a33693ab159dd089d74c0a2ea58cc
Author: Matthew Booth <mbooth at redhat.com>
Date:   Thu Nov 18 12:02:07 2010 +0000

    Release 0.7.3-2
    
    Pull in patch to fix i686 crasher when build on gcc 4.5

 augeas-0.7.3-01-c17cd53d.patch |   57 ++++++++++++++++++++++++++++++++++++++++
 augeas.spec                    |   12 +++++++-
 2 files changed, 68 insertions(+), 1 deletions(-)
---
diff --git a/augeas-0.7.3-01-c17cd53d.patch b/augeas-0.7.3-01-c17cd53d.patch
new file mode 100644
index 0000000..615cb98
--- /dev/null
+++ b/augeas-0.7.3-01-c17cd53d.patch
@@ -0,0 +1,57 @@
+commit c17cd53d8d4a643e4f7277da37d21dc3bade5ed6
+Author: Matthew Booth <mbooth at redhat.com>
+Date:   Fri Nov 12 11:24:30 2010 +0000
+
+    Fix crasher in ast.c:dict_pos on i686 with gcc 4.5 and -O2
+    
+    This patch works around what appears to be an optimization bug in gcc 4.5. The
+    symptom of the bug is that dict_pos, called from dict_lookup, receives an
+    invalid value when accessing dict->used. The following ticket describes the bug,
+    and includes a simple test case:
+    
+    https://fedorahosted.org/augeas/ticket/149
+    
+    Adding a printf to dict_lookup immediately before the dict_pos call reveals that
+    dict->used has a value of 30 in the crashing case on my F14 system. A printf
+    added to the first line of dict_pos shows dict->used has an apparent value of
+    16777246. This causes an invalid array lookup shortly afterwards, which causes
+    the crash. 16777246, interestingly, is 2^24 + 30, where 24 is the size of the
+    dict->used bitfield. This should obviously not be possible, suggesting either a
+    compiler bug or undefined behaviour due in incorrect use of the language. Having
+    re-read the relevant section of K&R, I can't see anything about this use of
+    bitfields which might be a problem, except that: 'Fields may be declared only as
+    ints; for portability, specify signed or unsigned explicitly.' uint32_t resolves
+    to 'unsigned int' on i686, and in any case, replacing it with 'unsigned int'
+    does not solve the problem. As it stands, I believe this is a bug in the
+    optimizer.
+    
+    The above ticket contains an alternate patch which copies dict in dict_pos,
+    which also prevents the crash. However, adding anything to dict_pos which
+    prevents the compiler from optimising dict away achieves the same result. For
+    example:
+    
+    printf("%p", dict);
+    
+    This patch instead removes the bitfields in struct dict. While this is a
+    workaround, these bitfields save at most 1 word of memory per struct, but at the
+    cost of mis-aligned access. The patch does not increase the size of
+    dict_max_size to UINT32_MAX, as the lower maximum serves as a better guard
+    against runaway memory allocation.
+
+diff --git a/src/ast.c b/src/ast.c
+index 4a3402d..6efcc3e 100644
+--- a/src/ast.c
++++ b/src/ast.c
+@@ -54,9 +54,9 @@ struct dict_node {
+    string */
+ struct dict {
+     struct dict_node **nodes;
+-    uint32_t          size : 24;
+-    uint32_t          used : 24;
+-    uint32_t          marked : 1;
++    uint32_t          size;
++    uint32_t          used;
++    bool              marked;
+ };
+ 
+ static const int dict_initial_size = 2;
diff --git a/augeas.spec b/augeas.spec
index 75c6df7..3793b48 100644
--- a/augeas.spec
+++ b/augeas.spec
@@ -1,12 +1,18 @@
 Name:           augeas
 Version:        0.7.3
-Release:        1%{?dist}
+Release:        2%{?dist}
 Summary:        A library for changing configuration files
 
 Group:          System Environment/Libraries
 License:        LGPLv2+
 URL:            http://augeas.net/
 Source0:        http://augeas.net/download/%{name}-%{version}.tar.gz
+# Format of the patch name is augeas-VERSION-NUMBER-HASH where VERSION
+# gives the first version where this patch was applied, NUMBER orders patches
+# against the same version, and HASH is the git commit hash from upstream
+# Fix crasher in ast.c:dict_pos on i686 with gcc 4.5 and -O2
+Patch0:         augeas-0.7.3-01-c17cd53d.patch
+
 BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 
 BuildRequires:  readline-devel libselinux-devel
@@ -43,6 +49,7 @@ The libraries for %{name}.
 
 %prep
 %setup -q
+%patch0 -p1
 
 %build
 %configure --disable-static
@@ -85,6 +92,9 @@ rm -rf $RPM_BUILD_ROOT
 %{_libdir}/pkgconfig/augeas.pc
 
 %changelog
+* Thu Nov 18 2010 Matthew Booth <mbooth at redhat.com> - 0.7.3-2
+- Fix crasher on i686 when compiled with gcc 4.5 (RHBZ#651992)
+
 * Fri Aug  6 2010 David Lutterkort <lutter at redhat.com> - 0.7.3-1
 - Remove upstream patches