Tiny C Compiler - C Scripting Everywhere - The Smallest ANSI C compiler ----------------------------------------------------------------------- Features: -------- - SMALL! You can compile and execute C code everywhere, for example on rescue disks (25KB for x86 executable). - FAST! tcc generates optimized x86 code. No byte code overhead. - UNLIMITED! Any C dynamic library can be used directly. TCC is heading torward full ANSI C compliance. TCC can of course compile itself. - Compile and execute C source directly. No linking or assembly necessary. Full C preprocessor included. - C script supported : just add '#!/usr/local/bin/tcc' at the first line of your C source, and execute it directly from the command line. Documentation: ------------- 1) Installation ***TCC currently only work on Linux x86***. Type 'make install' to compile and install tcc in /usr/local and /usr/local/lib/tcc. 2) Introduction We assume here that you know ANSI C. Look at the example ex1.c to know what the programs look like. The main limitation of tcc is that you cannot use floats. The include file can be used if you want a small basic libc include support (especially useful for floppy disks). Of course, you can also use standard headers, although they are slower to compile. You can begin your C script with '#!/usr/local/bin/tcc' on the first line and set its execute bits (chmod a+x your_script). Then, you can launch the C code as a shell or perl script :-) The command line arguments are put in 'argc' and 'argv' of the main functions, as in ANSI C. 3) Invokation '-Idir' : specify an additionnal include path. The default ones are: /usr/include, /usr/lib/tcc, /usr/local/lib/tcc. '-Dsym' : define preprocessor symbol 'sym' to 1. '-lxxx' : dynamically link your program with library libxxx.so. Standard library paths are checked, including those specificed with LD_LIBRARY_PATH. Only one source code can be compiled. If you have multiple source files, add one which includes all your sources. 4) Examples ex1.c: simplest example (hello world). Can also be launched directly as a script: ./ex2.c. ex2.c: more complicated example: find a number with the four operations given a list of numbers (benchmark). ex3.c: compute fibonacci numbers (benchmark). ex4.c: more complicated: X11 program. Very complicated test in fact because standard headers are being used ! Currently slow because parsing does not use hash tables. ex5.c: 'hello world' with standard glibc headers. tcc.c: TCC can compile itself. Used to check the code generator. prog.c: auto test for TCC which tests many subtle possible bugs. Used when doing 'make test'. Exact differences with ANSI C: ----------------------------- 1) Preprocessor - the preprocessor tokens are the same as C. It means that in some rare cases, preprocessed numbers are not handled exactly as in ANSI C. This approach has the advantage of being simpler and FAST! - __LINE__, __FILE__, __DATE__, __TIME__ are currently not handled. - #line not handled 2) C language - Parsing: variables cannot be initialized ('int a = 1' or 'int tab[2] = {1, 2}' not supported). - Cannot pass struct/union as value. Cannot assign struct/union (use memcpy instead). - Types: floating point numbers are not supported. - (BUG) 'char' and 'short' casts do not truncate correctly. - 'sizeof' may not work if too complex expression is given. Supported C extensions: ---------------------- - 'inline' keyword is ignored. Technical Description: --------------------- This is not my first C compiler (see my 'fbcc' compiler) but it contains the first C preprocessor I wrote. The project started as a joke to make the smallest C compiler. Then I expanded it torward ANSI compliance. This C compiler is particular because each feature was added while trying to be as simple and compact as possible. For example, no intermediate structure is used to store code or expressions. The TCC code generator directly generates linked binary code. It is rather unusual these days (see gcc for example which generates text assembly), but it allows to be very fast and surprisingly not so complicated. The TCC code generator is register based. It means that it could even generate good code for RISC processors. On x86, three temporary registers are used. When more registers are needed, one register is flushed in a new local variable. Constant propagation is done for all operations. Multiplications and divisions are optimized to shifts when appropriate. Logical operators are optimized by maintaining a special cache for the processor flags. &&, || and ! are optimized by maintaining a special 'jmp target' value. No other jmp optimization is currently performed because it would require to store the code in a more abstract fashion. The types and values descriptions are stored in a single 'int' variable (see VT_xxx constants). It was choosen in the first stages of development when tcc was much simpler. Now, it may not be the best solution. License: ------- TCC is distributed under the GNU Generic Public License (see COPYING file). I accept only patches where you give your copyright explictely to me to simplify licensing issues. Fabrice Bellard - Nov 11, 2001.