pC++/Sage++ Overview

Overview of pC++/Sage++

(version 1.7 / Sep 9 1994)

pC++

pC++ is a portable parallel C++ for high performance computers. pC++ is a language extention to C++ that permits data-parallel style opertations using "collections of objects" from some base "element" class. Member functions from this element class can be applied to the entire collection in parallel. This allows programmers to compose distributed data structures with parallel execution semantics. These distributed structures can be aligned and distributed over the memory hierarchy of the parallel machine much like HPF. pC++ also include a mechanism for encapsulating SPMD style computation in a thread-based computing model.

pC++ code is extremely portable. Just like Cfront translates C++ code into standard ANSI C that can be passed to the native C compiler, the pC++ preprocessor (written using Sage++) translates pC++ into C++, which is then compiled on the target architecture. Currently, pC++ has run-time systems for the following parallel machines:

Thinking Machines CM5
Silicon Graphics Challenge
Kendall Square KSR1
Intel Paragon
Meiko CS2
IBM SP1
BBN TC2000
Sequent Symmetry
homogeneous networks of workstations (PVM)

Furthermore, code can be developed and tested on the following "uniprocessor" workstations:

HP hpux
DEC Decstation (MIPS based)
DEC Alpha
Sun4
Cray C90
SGI Irix
IBM RS6000
NeXT

pC++ comes with a prototype version of the TAU tools (Tuning and Analysis Utilities), a visual programming and performance analysis environment for pC++. It is based on Sage++. The following four tools are available:

fancy (File ANd Class displaY) lets you browse through the files and classes used in the source text of the application, and lets you display the source text of functions, methods, or classes.
cagey (CAll Graph Extended displaY) lets you browse through the static call graph of the application.
classy (CLASS hierarchY browser) displays the class hierarchy defined in the current user application.
racy (Routine and data ACcess profile displaY) is a parallel profile data viewer. After compiling an application for profiling and running it, racy lets you browse through the function and collection profile data generated.

There is also tau, the TAU tools main control tool. It allows you to start the other tools, provides on-line, hyper-text help and some global functionality like loading another .dep file (the internal program tree form for pC++ programs).

There is also an experimental prototype of breeze, the barrier breakpoint debugger for pC++. Use with care. Application Notes:

1. Yes, you can call Fortran from pC++... even Thinking Machines "node" subset of CMF.

2. pC++ 1.x does not support the type of task parallelism you would need to do a distributed OS. It is intended for data-parallel problems only. In the future, there will be more support for task parallelism by providing ways in which pC++ will work with other object oriented systems. Watch this space for version 2.0.

Sage++

Sage++ is an object-oriented compiler preprocessor toolkit. Using Sage++ to transform source code is a three step process:

PARSING: Source code, either FORTRAN, pC++, or C, is parsed and saved as a machine-independent parse tree (".dep" file).
RESTRUCTURING: The ".dep" file is read by a Sage++-built restructuring tool. Sage++ uses member functions to manipulate the parse tree. For example, a restructuring program written with Sage++ could identify function-call sites, add variables, optimize loops, add tracing functions, or globally replace variables. After the parse tree has been modified, the new ".dep" file is saved.
UNPARSING: The new ".dep" file is "unparsed", recreating the source code and reflecting the changes that were made to the parsed form. After unparsing, the source code can be compiled with the native compiler.

Currently, the pC++/Sage++ system includes about 212K lines of code. For more information about pC++/Sage++, including the user's guides, view the On-line Documentation or the Program Files from the Main Menu.

sage@extreme.indiana.edu

Last updated: Tue Jan 26 18:06:10 1999