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

[Lisandro Dalcin]

On 1 November 2013 23:47, Lisandro Dalcin <dalcinl at gmail.com> wrote:
> On 1 November 2013 21:53, Stefan Behnel <stefan_ml at behnel.de> wrote:
>>
>> Erm - interesting. I looked through the code lines above and couldn't find
>> anything that looked suspicious. I hope I used the same source version as
>> you did (latest master?). Maybe I was just blinded by macros, but what I
>> saw looked rather reasonable...
>>
>
> Oh! Sorry, I've used branch 0.19.x, I'll check master and report back
> my findings.
>

OK, this is the commit in master I've used for test:

$ git show
commit 2cf64fd4e3e1f5d570d856c2e98fdc51930f1a50
Author: Robert Bradshaw <robertwb at gmail.com>
Date:   Fri Nov 1 09:05:24 2013 -0700

    Fix executable bits.

I got three warnings, see below. I understand the ones in _tempita.c
and FlowControl.c, but not sure about the others.



---
bug: anti-dce
model: |
  %523 = icmp ne i64 %522, 0, !dbg !1146
  -->  false
  ************************************************************
  :
  %518 = load %struct._object** @PyExc_UnboundLocalError, align 8, !dbg !1147
  %519 = call %struct._object* (%struct._object*, i8*, ...)*
@PyErr_Format(%struct._object* %518, i8* getelementptr inbounds ([49 x
i8]* @.str101, i32 0, i32 0), i8* getelementptr inbounds ([6 x i8]*
@.str52, i32 0, i32 0)), !dbg !1147
  br label %605, !dbg !1150
stack:
  - /home/dalcinl/Devel/cython-dev/Cython/Plex/Scanners.c:6632:0
  - /home/dalcinl/Devel/cython-dev/Cython/Plex/Scanners.c:1734:0
ncore: 1
core:
  - /home/dalcinl/Devel/cython-dev/Cython/Plex/Scanners.c:6492:0
    - null pointer dereference
---
bug: anti-simplify
model: |
  %2387 = icmp ne %struct._object* %__pyx_t_4.1, null, !dbg !3029
  -->  true
stack:
  - /home/dalcinl/Devel/cython-dev/Cython/Tempita/_tempita.c:24184:0
ncore: 1
core:
  - /home/dalcinl/Devel/cython-dev/Cython/Tempita/_tempita.c:591:0
    - null pointer dereference
---
bug: anti-simplify
model: |
  %7850 = icmp ne %struct._object* %78, null, !dbg !4512
  -->  true
stack:
  - /home/dalcinl/Devel/cython-dev/Cython/Compiler/FlowControl.c:16478:0
ncore: 1
core:
  - /home/dalcinl/Devel/cython-dev/Cython/Compiler/FlowControl.c:30460:0
    - null pointer dereference



-- 
Lisandro Dalcin
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