[issue20929] Undefined behavior flagged by Clang 3.4

[Jeffrey Walton]

New submission from Jeffrey Walton:

Downloaded Python-3.4.0rc3. Compiled with Clang 3.4, added -fsanitzie=undefined to CFLAGS. Ran 'make' and 'make check'.

Lots of issues, many are duplicates (see below). One or more of these issues might be the reason for `-fwrapv`.

This fellow from objimpl.h seems to be the source of many of the issues:

    #define _Py_AS_GC(o) ((PyGC_Head *)(o)-1)

*****

Modules/gcmodule.c:1718:5: runtime error: left shift of negative value -2
Objects/tupleobject.c:120:5: runtime error: left shift of negative value -3
Objects/typeobject.c:905:9: runtime error: left shift of negative value -3
Objects/dictobject.c:818:5: runtime error: left shift of negative value -3
Objects/methodobject.c:45:5: runtime error: left shift of negative value -3
Objects/listobject.c:178:5: runtime error: left shift of negative value -3
Modules/gcmodule.c:1703:9: runtime error: left shift of negative value -2
Modules/gcmodule.c:1693:5: runtime error: left shift of negative value -3
Objects/descrobject.c:9:5: runtime error: left shift of negative value -2
Modules/gcmodule.c:484:13: runtime error: left shift of negative value -3
Objects/tupleobject.c:195:5: runtime error: left shift of negative value -2
Modules/gcmodule.c:503:13: runtime error: left shift of negative value -4
Objects/exceptions.c:2205:5: runtime error: left shift of negative value -2
Objects/longobject.c:40:42: runtime error: index -3 out of bounds for type 'PyLongObject [262]'
Objects/frameobject.c:736:5: runtime error: left shift of negative value -3
Objects/funcobject.c:64:5: runtime error: left shift of negative value -3
Objects/methodobject.c:149:5: runtime error: left shift of negative value -2
Objects/funcobject.c:552:5: runtime error: left shift of negative value -2
Objects/descrobject.c:1364:5: runtime error: left shift of negative value -2
Objects/cellobject.c:16:5: runtime error: left shift of negative value -3
Objects/listobject.c:2744:5: runtime error: left shift of negative value -3
Objects/listobject.c:2751:5: runtime error: left shift of negative value -2
Objects/dictobject.c:3232:5: runtime error: left shift of negative value -3
Objects/dictobject.c:2826:5: runtime error: left shift of negative value -3
Objects/exceptions.c:89:5: runtime error: left shift of negative value -2
Objects/classobject.c:68:5: runtime error: left shift of negative value -3
Objects/classobject.c:193:5: runtime error: left shift of negative value -2
Objects/tupleobject.c:1079:5: runtime error: left shift of negative value -3
Objects/genobject.c:526:5: runtime error: left shift of negative value -3
Objects/tupleobject.c:948:5: runtime error: left shift of negative value -2
Objects/genobject.c:48:5: runtime error: left shift of negative value -2
Objects/genobject.c:53:5: runtime error: left shift of negative value -3
Objects/genobject.c:58:5: runtime error: left shift of negative value -2
Objects/cellobject.c:49:5: runtime error: left shift of negative value -2
Objects/typeobject.c:1170:9: runtime error: left shift of negative value -3
Objects/exceptions.c:662:5: runtime error: left shift of negative value -2
Objects/exceptions.c:1010:5: runtime error: left shift of negative value -2
Objects/exceptions.c:513:5: runtime error: left shift of negative value -2
./Modules/_io/fileio.c:479:5: runtime error: left shift of negative value -2
Objects/setobject.c:944:5: runtime error: left shift of negative value -3
Objects/unicodeobject.c:15267:5: runtime error: left shift of negative value -3
Objects/unicodeobject.c:15128:5: runtime error: left shift of negative value -2
Objects/typeobject.c:6720:5: runtime error: left shift of negative value -2
Objects/bytesobject.c:3006:5: runtime error: left shift of negative value -3
Objects/bytesobject.c:2869:5: runtime error: left shift of negative value -2
Objects/bytearrayobject.c:3094:5: runtime error: left shift of negative value -3
Objects/bytearrayobject.c:2959:5: runtime error: left shift of negative value -2
Objects/descrobject.c:1001:9: runtime error: left shift of negative value -3
Objects/descrobject.c:873:5: runtime error: left shift of negative value -2
Modules/gcmodule.c:861:13: runtime error: left shift of negative value -3
Objects/typeobject.c:2865:5: runtime error: left shift of negative value -2
Objects/dictobject.c:2643:9: runtime error: left shift of negative value -2
Objects/descrobject.c:943:5: runtime error: left shift of negative value -3
Objects/iterobject.c:26:5: runtime error: left shift of negative value -3
Objects/iterobject.c:33:5: runtime error: left shift of negative value -2
Objects/memoryobject.c:74:5: runtime error: left shift of negative value -3
Objects/memoryobject.c:639:5: runtime error: left shift of negative value -3
Objects/memoryobject.c:1060:5: runtime error: left shift of negative value -2
Objects/memoryobject.c:108:5: runtime error: left shift of negative value -2
./Modules/_io/bufferedio.c:402:5: runtime error: left shift of negative value -2
./Modules/_io/textio.c:1156:5: runtime error: left shift of negative value -2
Objects/descrobject.c:1262:9: runtime error: left shift of negative value -3
Objects/listobject.c:2046:22: runtime error: index 623 out of bounds for type 'PyObject *[256]'
Objects/dictobject.c:756:5: runtime error: left shift of negative value -2
Objects/funcobject.c:907:5: runtime error: left shift of negative value -2
Objects/funcobject.c:726:5: runtime error: left shift of negative value -2
Modules/gcmodule.c:1718:5: runtime error: left shift of negative value -2
Objects/tupleobject.c:120:5: runtime error: left shift of negative value -3
Objects/typeobject.c:905:9: runtime error: left shift of negative value -3
Objects/dictobject.c:818:5: runtime error: left shift of negative value -3
Objects/methodobject.c:45:5: runtime error: left shift of negative value -3
Objects/listobject.c:178:5: runtime error: left shift of negative value -3
Modules/gcmodule.c:1703:9: runtime error: left shift of negative value -2
Modules/gcmodule.c:1693:5: runtime error: left shift of negative value -3
Objects/descrobject.c:9:5: runtime error: left shift of negative value -2
Modules/gcmodule.c:484:13: runtime error: left shift of negative value -3
Objects/tupleobject.c:195:5: runtime error: left shift of negative value -2
Modules/gcmodule.c:503:13: runtime error: left shift of negative value -4
Objects/exceptions.c:2205:5: runtime error: left shift of negative value -2
Objects/longobject.c:40:42: runtime error: index -3 out of bounds for type 'PyLongObject [262]'
Objects/frameobject.c:736:5: runtime error: left shift of negative value -3
Objects/funcobject.c:64:5: runtime error: left shift of negative value -3
Objects/methodobject.c:149:5: runtime error: left shift of negative value -2
Objects/funcobject.c:552:5: runtime error: left shift of negative value -2
Objects/descrobject.c:1364:5: runtime error: left shift of negative value -2
Objects/cellobject.c:16:5: runtime error: left shift of negative value -3
Objects/listobject.c:2744:5: runtime error: left shift of negative value -3
Objects/listobject.c:2751:5: runtime error: left shift of negative value -2
Objects/dictobject.c:3232:5: runtime error: left shift of negative value -3
Objects/dictobject.c:2826:5: runtime error: left shift of negative value -3
Objects/exceptions.c:89:5: runtime error: left shift of negative value -2
Objects/classobject.c:68:5: runtime error: left shift of negative value -3
Objects/classobject.c:193:5: runtime error: left shift of negative value -2
Objects/tupleobject.c:1079:5: runtime error: left shift of negative value -3
Objects/genobject.c:526:5: runtime error: left shift of negative value -3
Objects/tupleobject.c:948:5: runtime error: left shift of negative value -2
Objects/genobject.c:48:5: runtime error: left shift of negative value -2
Objects/genobject.c:53:5: runtime error: left shift of negative value -3
Objects/genobject.c:58:5: runtime error: left shift of negative value -2
Objects/cellobject.c:49:5: runtime error: left shift of negative value -2
Objects/typeobject.c:1170:9: runtime error: left shift of negative value -3
Objects/exceptions.c:662:5: runtime error: left shift of negative value -2
Objects/exceptions.c:1010:5: runtime error: left shift of negative value -2
Objects/exceptions.c:513:5: runtime error: left shift of negative value -2
./Modules/_io/fileio.c:479:5: runtime error: left shift of negative value -2
Objects/unicodeobject.c:15267:5: runtime error: left shift of negative value -3
Objects/unicodeobject.c:15128:5: runtime error: left shift of negative value -2
Objects/typeobject.c:6720:5: runtime error: left shift of negative value -2
Objects/setobject.c:944:5: runtime error: left shift of negative value -3
Objects/bytesobject.c:3006:5: runtime error: left shift of negative value -3
Objects/bytesobject.c:2869:5: runtime error: left shift of negative value -2
Objects/bytearrayobject.c:3094:5: runtime error: left shift of negative value -3
Objects/bytearrayobject.c:2959:5: runtime error: left shift of negative value -2
Objects/descrobject.c:1001:9: runtime error: left shift of negative value -3
Objects/descrobject.c:873:5: runtime error: left shift of negative value -2
Modules/gcmodule.c:861:13: runtime error: left shift of negative value -3
Objects/typeobject.c:2865:5: runtime error: left shift of negative value -2
Objects/iterobject.c:26:5: runtime error: left shift of negative value -3
Objects/iterobject.c:33:5: runtime error: left shift of negative value -2
Objects/dictobject.c:2643:9: runtime error: left shift of negative value -2
Objects/descrobject.c:1262:9: runtime error: left shift of negative value -3
Objects/memoryobject.c:74:5: runtime error: left shift of negative value -3
Objects/memoryobject.c:639:5: runtime error: left shift of negative value -3
running build
Objects/memoryobject.c:1060:5: runtime error: left shift of negative value -2
Objects/memoryobject.c:108:5: runtime error: left shift of negative value -2
running build_ext
./Modules/_io/bufferedio.c:402:5: runtime error: left shift of negative value -2
./Modules/_io/textio.c:1156:5: runtime error: left shift of negative value -2
INFO: Can't locate Tcl/Tk libs and/or headers
Objects/tupleobject.c:878:9: runtime error: left shift of negative value -2
Objects/tupleobject.c:896:5: runtime error: left shift of negative value -3

----------
components: Build
files: python-3-4-make.txt
messages: 213604
nosy: Jeffrey.Walton
priority: normal
severity: normal
status: open
title: Undefined behavior flagged by Clang 3.4
type: behavior
versions: Python 3.4
Added file: http://bugs.python.org/file34425/python-3-4-make.txt

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue20929>
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