The SubC Compiler

SubC is a fast and simple public domain compiler for a clean subset of the C programming language. It can compile itself and passes gcc -Wall -pedantic. Its internals are described in detail in the book

Practical Compiler Construction

Note that SubC is a teaching vehicle rather than a production compiler. Check the README files to find out what it can and cannot do. If you are planning to do something more serious with SubC, you may want to get the development version rather than the book version.

Current book version (2nd edition): subc-2022.zip (~94KB), README, Fixes

Development version: subc-20220127.tgz (~129KB), README, Changes, Status

Experimental version: subc-20220127-typedef.tgz (~129KB), provides typedef, but widely untested, DOS support broken

Previous versions: subc-20161212.tgz (~120KB), subc-20140425b.tgz (~110KB)

DOS executables: subc-dos.zip (~140KB, experimental)

Old book version (1st edition): subc-2012.zip (~75KB), README

View the compiler sources online (2nd edition book version)

Check out Quan Tran's Go version of SubC
(most of the critical bugs reported by him have been fixed by now)

The Windows runtime support code has been written by Jean-Marc Lienher. The Darwin back-end and startup module have been contributed by Romain LWPB. The Linux/x86-64 and NetBSD/386 runtime support as well as proper signal handling for NetBSD were provided by Minux. Thank you!

Targets

The book version runs on FreeBSD/386 exclusively.

The development version supports the following platforms:

• The Darwin port is known not to build and needs some work due to bit rot.
• The DOS version is rather experimental.

Major Changes since the Book Version

New Platforms

See above.

Internal

• Improved code generator
• Added optimizer
• Changed calling conventions to standard C (right-to-left), removed __argc hack

Language Level

• Added #error, #line, and #pragma commands
• Added support for struct and union
• Prototypes may have the static storage class
• extern identifiers may be declared locally
• enum may be local
• The auto and register keywords are recognized (as no-ops)
• &array is valid syntax