This commit is contained in:
bellard 2001-11-11 22:51:50 +00:00
parent eb0e3e70dc
commit 4dceee3677
2 changed files with 42 additions and 8 deletions

47
README
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@ -5,22 +5,20 @@ Features:
--------
- SMALL! You can compile and execute C code everywhere, for example on
rescue disks.
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 torwards full ANSI C compliance. TCC can of course compile
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 !
- For adventurers, tcc is conceived to be able to generate code for
other targets.
line of your C source, and execute it directly from the command
line.
Documentation:
-------------
@ -37,7 +35,7 @@ Type 'make install' to compile and install tcc in /usr/local and
We assume here that you know ANSI C. Look at the example ex1.c to know
what the programs look like.
The main limitations of tcc are that you cannot use floats.
The main limitation of tcc is that you cannot use floats.
The include file <tcclib.h> can be used if you want a small basic libc
include support (especially useful for floppy disks). Of course, you
@ -117,6 +115,39 @@ 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:
-------
@ -126,4 +157,4 @@ file).
I accept only patches where you give your copyright explictely to me
to simplify licensing issues.
Fabrice Bellard - Nov 11, 2001.
Fabrice Bellard - Nov 11, 2001.

3
TODO
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@ -2,9 +2,12 @@ TODO list:
Critical:
- initializers
- add hash tables for symbols (useful for long programs)
- 0 is pointer - fix type compare
- add message if external function or variable not found.
- add float/double support (should be as small as possible while being
usable for RISC code generator too).
Not critical: