8d44851d65
The comment suggests this was meant to detect unions, but in fact it
compared f->c, the union/struct size, against f->next->c, the first
element's offset.
This affected only zero-length structs/unions with a first (zero-length)
element, as in this code:
struct u2 {
};
struct u {
struct u2 u2;
} u;
struct u f(struct u x)
{
return x;
}
However, such structures turned out to be broken anyway, as code like this
was generated for the above f:
0000000000000000 <f>:
0: 55 push %rbp
1: 48 89 e5 mov %rsp,%rbp
4: 48 81 ec 10 00 00 00 sub $0x10,%rsp
b: 66 0f d6 45 f8 movq %xmm0,-0x8(%rbp)
10: 66 0f 6e 45 f8 movd -0x8(%rbp),%xmm0
15: e9 00 00 00 00 jmpq 1a <f+0x1a>
1a: c9 leaveq
1b: c3 retq
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 optimized x86 code. No byte code overhead. Compile, assemble and link about 7 times faster than 'gcc -O0'. - UNLIMITED! Any C dynamic library can be used directly. TCC is heading torward 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 a i386/x86_64/arm Linux/OSX/FreeBSD host (for Windows read tcc-win32.txt) Note: For OSX and FreeBSD, gmake should be used instead of make. ./configure make make test make install Alternatively, out-of-tree builds are supported: you may use different directories to hold build objects, kept separate from your source tree: mkdir _build cd _build ../configure make make test make install Texi2html 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 is available for the Windows port in tcc-win32.txt. License: ------- TCC is distributed under the GNU Lesser General Public License (see COPYING file). Fabrice Bellard.