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 stable or experimental version rather than the book version.

SubC Compiler sources, book version (zip, ~75KB), README

SubC Compiler sources, current version (tgz, ~85KB), README

View the compiler sources online (book version)

Current Targets

Book Version	Current Version
FreeBSD-386	FreeBSD-386
	FreeBSD-x86-64
	Linux-386
	Linux-x86-64
	NetBSD-x86-64
	Windows/386 via MinGW

SubC now has an synthesizing back-end, which generates more efficient code than the book version of the compiler. It is included in the current branch and enabled by default.

The Windows runtime support code has been written by Jean-Marc Lienher (cod5.org). Many thanks for the great effort!

History of Changes

Added complete Windows-386/MinGW runtime support. Thanks, Jean-Marc Lienher!
Ported the synthesizing code generator to the x86-64 processor.
Added a synthesizing code generator for the 386 processor.
Added a Linux/x86-64 startup (crt0) module. Thanks, minux!
Fix: middle argument of ?: is an expression, not a logic op. (a?b,c:d is a valid expression).
Removed all GNU libc dependencies from the Linux startup module.
Added a Linux/386 startup (crt0) module.
Added a FreeBSD/x86-64 startup (crt0) module.
Added a NetBSD/x86-64 startup (crt0) module.
Added an x86-64 back-end.
Added the (non-standard) kprintf() function, which is like fprintf(), but uses a file descriptor.
Added the #error, #line, and #pragma commands.
FILEs are now structs and can no longer be mistaken for ints by the type checker.
jmp_buf is now a struct; setjmp() and longjmp() must be called with &jmp_buf (this is a bug).
Added ~~experimental~~ support for structs and unions.
Prototypes may have the static storage class.
Extern identifiers may now be declared locally.
Enums may now be local.
The auto and register keywords are now recognized (as no-ops).
&array is now valid syntax (you no longer have to write &array[0]).

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