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The BOUNDS_CHECKING_ON/BOUNDS_CHECKING_OFF is not working for signal/sigaction/fork. The reason is that the code stops bound checking for the whole application. This result in wrong handling of __bound_local_new/__bound_local_delete and malloc/calloc/realloc/free. Consider the following code: void tst(int n) { int i, arr[n]; for (i = 0; i < n; i++) arr[i] = 0; } void *some_thread(void *dummy) { while (running) { tst(10); tst(20); } } void signal_handler(int sig) { ... } When the signal handler is called the some_thread code can be interrupted when is just registered the arr[10] data. When the signal handler is leaved the arr[10] is still registered and did not see the call to deregister arr[10] and then register arr[20]. The code resumes when tst(20) is running. This results in a bound checking error when i >= 10. To solve the above problem I changed the bound checking code to use tls (thread local storage) for the no_checking variable. This also makes it now possible to redirect signal/sigaction/fork code through the bound checking library and disable checking when a signal is running and to correct the bounds_sem for the fork child process. The BOUNDS_CHECKING_ON/BOUNDS_CHECKING_OFF is not needed any more for signal/sigaction/fork. In fact I could remove them from all my applications. The use of the tls function code slows down the code by about 10%. So if the slowdown due to bound checking was 5. It is now 5.5 times slower. For x86_64/i386 I also allowed to use __thread variable in bcheck.c when compiled with gcc with: make x86_64-libtcc1-usegcc=yes make i386-libtcc1-usegcc=yes This makes code run faster due to use of gcc and __thread variable. With the __thread variable there is no 10% slowdown. For other targets this does not work because stabs is not supported. Changes: lib/bcheck.c: - Add TRY_SEM - Add HAVE_SIGNAL/HAVE_SIGACTION/HAVE_FORK/HAVE_TLS_FUNC/HAVE_TLS_VAR - HAVE_SIGNAL: redirect signal() call if set. - HAVE_SIGACTION: redirect sigaction() call if set. - HAVE_FORK: redirect fork() call if set. - HAVE_TLS_FUNC: If target has tls function calls. - HAVE_TLS_VAR: If target has __thread tls support. - Replace all no_checking refecrences to NO_CHECKING_SET/NO_CHECKING_GET macros tcc-doc.texi: - Remove examples for signal/sigaction/fork code. - Add some explanation for signal/sigaction/fork code. - Add documentaion for __bounds_checking(). tccelf.c: - Add support for SHF_TLS tests/tests2/114_bound_signal.c: - Remove BOUNDS_CHECKING_ON/BOUNDS_CHECKING_OFF - Add code to trigger failure when tls is not working. x86_64-link.c: - Add support for R_X86_64_TLSGD/R_X86_64_TLSLD/R_X86_64_DTPOFF32/R_X86_64_TPOFF32 i386-link.c: - Add support for R_386_TLS_GD/R_386_TLS_LDM/R_386_TLS_LDO_32/R_386_TLS_LE |
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examples | ||
include | ||
lib | ||
tests | ||
win32 | ||
.gitignore | ||
arm64-gen.c | ||
arm64-link.c | ||
arm-asm.c | ||
arm-gen.c | ||
arm-link.c | ||
c67-gen.c | ||
c67-link.c | ||
Changelog | ||
CodingStyle | ||
coff.h | ||
configure | ||
conftest.c | ||
COPYING | ||
elf.h | ||
i386-asm.c | ||
i386-asm.h | ||
i386-gen.c | ||
i386-link.c | ||
i386-tok.h | ||
il-gen.c | ||
il-opcodes.h | ||
libtcc.c | ||
libtcc.h | ||
Makefile | ||
README | ||
RELICENSING | ||
riscv64-asm.c | ||
riscv64-gen.c | ||
riscv64-link.c | ||
stab.def | ||
stab.h | ||
tcc-doc.texi | ||
tcc.c | ||
tcc.h | ||
tccasm.c | ||
tcccoff.c | ||
tccelf.c | ||
tccgen.c | ||
tcclib.h | ||
tccmacho.c | ||
tccpe.c | ||
tccpp.c | ||
tccrun.c | ||
tcctok.h | ||
tcctools.c | ||
texi2pod.pl | ||
TODO | ||
USES | ||
VERSION | ||
x86_64-asm.h | ||
x86_64-gen.c | ||
x86_64-link.c |
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 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 a i386/x86_64/arm Linux/OSX/FreeBSD host ./configure make make test make install Notes: For OSX and FreeBSD, 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 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.