TODAY: PL Seminar - Run-time Type Checking

[Suan Yong <suan@xxxxxxxxxxx>]

There will be a PL seminar today (Thursday, 20 July) at 4:00 pm in room
CS 2310. The abstract for the talk follows.

This is a practice for a talk we'll be giving for IBM, so attendance and
feedback would be appreciated. Cookies will be provided.

Sorry for the late notice.

Alexey/Suan

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Debugging via Run-Time Type Checking

Alexey Loginov, Suan Yong, Susan Horwitz, Thomas Reps

This paper describes the design and implementation of a tool for C
programs that provides run-time checks based on type information.  The
tool instruments a program to monitor the type stored in each memory
location.  Whenever a value is written into a location, the location's
run-time type tag is updated to match the type of the value.  Also,
the location's static type is compared with the value's type; if there
is a mismatch, a warning message is issued.  Whenever the value in a
location is used, its run-time type tag is checked, and if the type is
inappropriate in the context in which the value is being used, an
error message is issued.

The tool has been used to pinpoint the cause of bugs in several Solaris
utilities and Olden benchmarks, usually providing information that is
succinct and precise. It has the potential to find all of the run-time
storage violations found by Purify (e.g., a use of an uninitialized
variable or an out-of-bounds array access), as well as errors that Purify
cannot detect (e.g., a write into one member of a union followed by a read
from a different member).  Furthermore, in addition to reporting an error
at the time of an access violation, our tool's warning messages can
provide additional help in tracking down the original cause of the error.