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.

- FAST! tcc generates machine code for i386, x86_64, arm, aarch64 or
  riscv64.  Compiles and links about 10 times faster than 'gcc -O0'.

- UNLIMITED! Any C dynamic library can be used directly. TCC is
  heading toward full ISOC99 compliance. TCC can of course compile
  itself.

- SAFE! tcc includes an optional memory and bound checker. Bound
  checked code can be mixed freely with standard code.

- Compile and execute C source directly. No linking or assembly
  necessary. Full C preprocessor included.

- C script supported : just add '#!/usr/local/bin/tcc -run' at the first
  line of your C source, and execute it directly from the command
  line.

Documentation:
-------------

1) Installation on Linux, BSD variants or macOS hosts:

   ./configure
   make
   make test
   make install

   Notes: On BSD hosts, gmake should be used instead of make.
   For Windows read tcc-win32.txt.

makeinfo must be installed to compile the doc.  By default, tcc is
installed in /usr/local/bin.  ./configure --help  shows configuration
options.


2) Introduction

We assume here that you know ANSI C. Look at the example ex1.c to know
what the programs look like.

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
can also use standard headers, although they are slower to compile.

You can begin your C script with '#!/usr/local/bin/tcc -run' 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) Examples

ex1.c: simplest example (hello world). Can also be launched directly
as a script: './ex1.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 ! As for ex1.c, can also be launched
directly as a script: './ex4.c'.

ex5.c: 'hello world' with standard glibc headers.

tcc.c: TCC can of course compile itself. Used to check the code
generator.

tcctest.c: auto test for TCC which tests many subtle possible bugs. Used
when doing 'make test'.

4) Full Documentation

Please read tcc-doc.html to have all the features of TCC.  Additional
information for the Windows port is in tcc-win32.txt.

License:
-------

TCC is distributed under the GNU Lesser General Public License (see
COPYING file).

Fabrice Bellard.

WebAssembly (wasm32 / WASI)
---------------------------

A cross compiler targeting wasm32 with the wasi-libc sysroot:

    make cross-wasm32 CONFIG_WASI_SYSROOT=/path/to/wasi-sysroot
    ./wasm32-tcc -B. -o hello.wasm hello.c
    wasmtime hello.wasm

The sysroot is the one shipped by wasi-sdk or the wasi-libc package
(include/wasm32-wasip1, lib/wasm32-wasip1); the default location is
/opt/homebrew/opt/wasi-libc/share/wasi-sysroot. tcc links wasi-libc's
libc.a itself (it reads wasm object files) and follows the wasm C ABI,
so tcc compiled code interoperates with clang compiled objects.
Undefined functions named "module.name" (via asm labels, e.g.
int f(int) __asm__("wasi_snapshot_preview1.fd_close")) are imported
from that module. setjmp/longjmp use the wasm exception handling
proposal (as LLVM does: longjmp throws, functions calling setjmp catch),
so the runtime must support it; wasmtime and current browsers do.
Not supported: inline assembly, bounds checking, threads, tcc -run.
'make test-wasm' runs tests/tests2 and tests/wasm under wasmtime. See
the overview in wasm32-gen.c for the design.

tcc can compile itself to wasm ('make tcc.wasm'). The result is a
wasm32 cross compiler that runs under any WASI runtime, with the
sysroot mounted at /wasi-sysroot and libtcc1/include at /tcc:

    wasmtime run --dir . --dir /path/to/wasi-sysroot::/wasi-sysroot \
        --dir .::/tcc tcc.wasm -o hello.wasm hello.c

The wasm workflow in .github builds and tests tcc.wasm and uploads it
as an artifact.
