A visualization technique that makes it possible to display and analyze line count profile data is described. The technique is to make a reduced picture of code with the line execution counts identified with color. Hot spots are shown in red, warm spots in orange, and so on. It is possible to identify nonexecuted code and nonexecutable code such as declarations and static tables.>

Abstract Run‐time checking of array subscripts and pointer bounds was added to the Portable C Compiler (PCC). Memory overwrite bugs are then caught as they happen instead of when the overwritten memory is used later in the program execution. The run‐time checking compiler is used both to find the true cause of a core dump and to eliminate run‐time errors as the cause of unexpected program behavior. On average, it takes about 40 percent longer to compile, the generated code is about three times larger, and it runs about ten times slower. This performance may seem slow, but it typically reduces days of debugging to less than an hour. The implementation described herein can be adapted to any C compiler as it describes how to generate run‐time checking code in a machine/compiler independent way by changing the intermediate expression trees. In four years of use it has found latent bugs and the cause of intermittent core dumps in programs used for many years by thousands of people.

The Seesoft software visualization system allows one to analyze up to 50000 lines of code simultaneously by mapping each line of code into a thin row. The color of each row indicates a statistic of interest, e.g., red rows are those most recently changed, and blue are those least recently changed. Seesoft displays data derived from a variety of sources, such as version control systems that track the age, programmer, and purpose of the code (e.g., control ISDN lamps, fix bug in call forwarding); static analyses, (e.g., locations where functions are called); and dynamic analyses (e.g., profiling). By means of direct manipulation and high interaction graphics, the user can manipulate this reduced representation of the code in order to find interesting patterns. Further insight is obtained by using additional windows to display the actual code. Potential applications for Seesoft include discovery, project management, code tuning, and analysis of development methodologies.>

Abstract Debugging tools are usually highly machine and compiler dependent programs that are either impossible to move or require a tremendous effort to move to another machine. This paper describes Ctrace, a portable debugging tool for the C language that provides the same, easy‐to‐use debugging environment on all machines. A similar debugger can be written for any language. Ctrace is a preprocessor that inserts source language debugging code into the program before compilation that, at execution time, prints the text of each source language statement along with the values of variables it uses and modifies. Redundant trace output from program loops is detected and eliminated. Tracing can be limited to selected statements or functions. Ctrace has shown its usefulness and popularity by its installation on over 200, computers at Bell Laboratories. It has proven its portability by being used to test software on four different operating systems and nine different processors.