[Cython] [cython-users] "Stack" checker for undefined behaviour in C code

[Lisandro Dalcin]

On 1 November 2013 15:55, Lisandro Dalcin <dalcinl at gmail.com> wrote:
> On 31 October 2013 20:25, Stefan Behnel <stefan_ml at behnel.de> wrote:
>> Hi,
>>
>> I just came across this paper:
>>
>> http://pdos.csail.mit.edu/~xi/papers/stack-sosp13.pdf
>>
>> They describe an analysis tool that checks C code for bugs that exploit
>> undefined behaviour and that are thus up to the mercy of compiler
>> assumptions and "optimisations" to do the right thing or not. They made it
>> available on github:
>>
>> https://github.com/xiw/stack/
>>
>> If anyone wants to take the time to set it up for checking some Cython
>> generated code, I'd be interested to see if it finds something.
>>
>
> I tested with mpi4py and got 0 warnings. I'll run it on Cython's testsuite.
>
>

I got two warnings out of 'python setup.py build'


Analyzing ./build/temp.linux-x86_64-2.7/home/dalcinl/Devel/cython-dev/Cython/Plex/Scanners.17387.ll
Analyzing ./build/temp.linux-x86_64-2.7/home/dalcinl/Devel/cython-dev/Cython/Plex/Actions.17412.ll
Analyzing ./build/temp.linux-x86_64-2.7/home/dalcinl/Devel/cython-dev/Cython/Runtime/refnanny.17706.ll
Analyzing ./build/temp.linux-x86_64-2.7/home/dalcinl/Devel/cython-dev/Cython/Compiler/Code.17659.ll
Analyzing ./build/temp.linux-x86_64-2.7/home/dalcinl/Devel/cython-dev/Cython/Compiler/FlowControl.17614.ll
Analyzing ./build/temp.linux-x86_64-2.7/home/dalcinl/Devel/cython-dev/Cython/Compiler/Lexicon.17437.ll
Analyzing ./build/temp.linux-x86_64-2.7/home/dalcinl/Devel/cython-dev/Cython/Compiler/Visitor.17577.ll
Analyzing ./build/temp.linux-x86_64-2.7/home/dalcinl/Devel/cython-dev/Cython/Compiler/Scanning.17462.ll
Analyzing ./build/temp.linux-x86_64-2.7/home/dalcinl/Devel/cython-dev/Cython/Compiler/Parsing.17489.ll
Generated 2 warnings, see pstack.txt for details.
[dalcinl at kw2060 build.bak]$ cat pstack.txt
---
bug: anti-dce
model: |
  %523 = icmp ne i64 %522, 0, !dbg !1139
  -->  false
  ************************************************************
  :
  %518 = load %struct._object** @PyExc_UnboundLocalError, align 8, !dbg !1140
  %519 = call %struct._object* (%struct._object*, i8*, ...)*
@PyErr_Format(%struct._object* %518, i8* getelementptr inbounds ([49 x
i8]* @.str100, i32 0, i32 0), i8* getelementptr inbounds ([6 x i8]*
@.str52, i32 0, i32 0)), !dbg !1140
  br label %605, !dbg !1143
stack:
  - /home/dalcinl/Devel/cython-dev/Cython/Plex/Scanners.c:6651:0
  - /home/dalcinl/Devel/cython-dev/Cython/Plex/Scanners.c:1752:0
ncore: 1
core:
  - /home/dalcinl/Devel/cython-dev/Cython/Plex/Scanners.c:6511:0
    - null pointer dereference
---
bug: anti-simplify
model: |
  %7699 = icmp ne %struct._object* %78, null, !dbg !4455
  -->  true
stack:
  - /home/dalcinl/Devel/cython-dev/Cython/Compiler/FlowControl.c:16304:0
ncore: 1
core:
  - /home/dalcinl/Devel/cython-dev/Cython/Compiler/FlowControl.c:30198:0
    - null pointer dereference



-- 
Lisandro Dalcin
---------------
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