C compiler for Unix and Unix-like operating systems
The Portable C Compiler (also known as pcc or sometimes pccm - portable C compiler machine) is an early compiler for the C programming language written by Stephen C. Johnson of Bell Labs in the mid-1970s,[1] based in part on ideas proposed by Alan Snyder in 1973,[2][3]
and "distributed as the C compiler by Bell Labs... with the blessing of Dennis Ritchie."[4]
Being one of the first compilers that could easily be adapted to output code for different computer architectures, the compiler had a long life span. It debuted in Seventh Edition Unix and shipped with BSD Unix until the release of 4.4BSD in 1994, when it was replaced by the GNU C Compiler. It was very influential in its day, so much so that at the beginning of the 1980s, the majority of C compilers were based on it.[5] Anders Magnusson and Peter A Jonsson restarted development of pcc in 2007, rewriting it extensively to support the C99 standard.[6]
Features
Key features of pcc are its portability and improved diagnostic capabilities. The compiler was designed so that only a few of its source files are machine-dependent. It is relatively robust to syntax errors and performs more thorough validity checks than its contemporaries.[according to whom?]
The first C compiler, written by Dennis Ritchie, used a recursive descent parser, incorporated specific knowledge about the PDP-11, and relied on an optional machine-specific optimizer to improve the assembly language code it generated. In contrast, Johnson's pccm was based on a yacc-generated parser and used a more general target machine model. Both compilers produced target-specific assembly language code which they then assembled to produce linkable object modules.
Later versions of PCC, known within Bell Labs as "QCC" and "RCC," supported other target architecture models.[citation needed]
The language that PCC implements is an extended version of K&R C that Bjarne Stroustrup has called "Classic C", incorporating the void return type (for functions that don't return any value), enumerations and structure assignment.[4]
Current version
A new version of pcc, based on the original by Steve Johnson, is now maintained by Anders Magnusson.[6] The compiler is provided under the BSD licence and its development is funded by a non-profit organization called BSD Fund. According to Magnusson:
The big benefit of it (apart from that it's BSD licensed, for license geeks) is that it is fast, 5-10 times faster than gcc, while still producing reasonable code. <...> [I]t is also quite simple to port...
This new version was added to the NetBSD pkgsrc and OpenBSD source trees in September 2007,[8] and later into the main NetBSD source tree.[9] There had been some speculation that it might eventually be used to supplant the GNU C Compiler on BSD-based operating systems,[10] though FreeBSD[11][12] and NetBSD[13] are both looking to Clang as a potential replacement, and Theo de Raadt of OpenBSD asserts that pcc is not ready yet to be a gcc replacement, and the disposal of gcc is not top priority.[14] On December 29, 2009, pcc became capable of building a functional x86 OpenBSD kernel image.[15]
pcc version 1.0 was released on 1 April 2011.[16]
As of this release, the compiler supports x86 and x64 processor architectures and runs on NetBSD, OpenBSD, FreeBSD, various Linux distributions, and Microsoft Windows.[17]
Further development, including support for more architectures, and FORTRAN 77 and C++ front ends, is continuing as of 2022.
PCC was removed from the OpenBSD source tree in 2012.[18] Development on it had stalled and no maintainer had stepped up to develop it into something that could make a practical alternative to GNU Compiler Collection.[19][20]
The latest version of pcc, namely 1.1.0, was released on 10 December 2014.[21]
