Visualization of Compiler Graphs



The VCG tool reads a textual and readable specification of a graph and visualizes the graph. If not all positions of nodes are fixed, the tool layouts the graph using several heuristics as reducing the number of crossings, minimizing the size of edges, centering of nodes. The specification language of the VCG tool is nearly compatible to GRL, the language of the edge tool, but contains many extensions. The VCG tool allows folding of dynamically or statically specified regions of the graph. It uses colors and runs on X11 and MS Windows 3.1. (An older version runs on Sunview).

The VCG tool has been developed and tested on a Sparc ELC with SunOs 4.1.3, X11 Release 5 and Release 6, and different ANSI C and K&R C compilers. It has been migrated to MS Windows 3.1. with the Visual C++ compiler and the library wxWindows. It has further been tested on Solaris (SunOs 5.3, gcc only), on a Silicon Graphics (IRIX 5.2), on a IBM R6000 (AIX 2 with AIX Windows), on a HP-UX (X11R5, c89), on a DecStation (ULTRIX, X11R5, gcc only), on Linux (X11R5, gcc), and on OSF (X11R5, gcc). Recently, a user migrated the tool to VAX/VMS.

Windows Availablitity

Based on the VCG code, the company AbsInt has developed a visualization tool AISee. See http://www.absint.com/aisee/ for more information. I'm not involved in the AISee development anymore. As far as I know, it is free for research usage. Since I didn't have the time for porting myself lately, this is the best choice for Windows 2000/95/NT.



These examples are in color. Select the items ...


The software is distributed under the terms of the GNU General Public License. The software is available by anonymous ftp at ftp.cs.uni-sb.de ( in the directory /pub/graphics/vcg. This site is in Germany. Select the following points to get ... (packages tar'd + gzip'd, documents PostScript + gzip'd, on MSDOS pkzip'd) ...
See also my publications about graph layout.
Some mirror sites:

Mailing List

There is a mailing list vcg-users@cs.uni-sb.de that distributes new information on the VCG tool. If you want to be added to this list, or if you need more information, please contact
Last change: 28.9.1995 Georg Sander / sander@cs.uni-sb.de