Fixes potential writes past the allocated space with mostly
illegal flex array initializers. (60_errors_and_warnings.c
:test_var_array)
In exchange suspicious precautions such as section_reserve
or checks with sec->data_allocated were removed. (There is
an hard check 'init_assert()' for now but it's meant to be
just temporary)
Also, instead of filling holes, always memset(0) structures
& arrays on stack. Sometimes more efficient, sometimes isn't.
At least we can omit putting null initializers.
About array range inititializers: Reparsing tokens has a
small problem with sideeffects, for example
int c = 0, dd[] = { [0 ... 1] = ++c, [2 ... 3] = ++c };
Also, instead of 'squeeze_multi_relocs()', delete pre-existing
relocations in advance. This works even if secondary initializers
don't even have relocations, as with
[0 ... 7] = &stuff,
[4] = NULL
Also, in tcc.h: new macro "tcc_internal_error()"
Always fine to try out things but not everything must be shown
to the public. ;)
Also, AFAIK pointers must compare equal only if derived directly
from each other (for example by cast to void* and back).
This reverts commit 8f9bf3f223.
The init range with symbols did only init the first value.
The relocation for all other symbols was missing.
Also see testcase.
tccgen.c:
- New function get_init_string
- Use macro processing in decl_designator for each init string
- Use get_init_string in decl_initializer_alloc
tccelf.c:
- Fix insertion sort in squeeze_multi_relocs
tests/tests2/90_struct-init.c:
- Add test case test_init_ranges
tccelf.c:
- Check if symbol is in data section and UNDEF. Then generate new
relocation and let dynamic linker solve it.
tests/tests2/42_function_pointer.c:
- Add new test code
from 43ae350390
and a3578379fb
Sorry, but this feature appears to be rather a personal
experiment than generically interesting for other people.
Also those "other people" always have some interest in
TCC staying simple.
One can still avoid the startup code from libtcc1.a simply
by providing __start explicitly.
While at it: Tidy tccpe.c:pe_add_runtime(), somewhat.
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
Most support was already present.
arm-link.c:
- set RELOCATE_DLLPLT to 1
- create_plt_entry:
- remove DLLs unimplemented!
- leave code gen to relocate_plt. only set got_offset
- relocate_plt:
- create code for got entry
- relocate:
- Add TCC_OUTPUT_DLL for R_ARM_ABS32
tccelf.c:
- prepare_dynamic_rel:
- Add R_ARM_ABS32
- alloc_sec_names:
- Always add SHT_ARM_ATTRIBUTES section
- New function create_arm_attribute_section
- elf_output_file:
- call create_arm_attribute_section
tested on win32/64 to pass the tests when enabled
- libtcc.c :
let tcc define __leading_underscore if enabled
tcc_add_symbol() : add _ automatically
- tccelf.c : remove tcc_get_symbol_err(), find_c_sym()
currently symbol length is limited to 256 in several
places, so we can use a fixed local buffer for now as well.
- win32/lib/crtinit.c : new file for init/fini
- lib/*.S, tests7* : use __leading_underscore
- bt-log.c: this file wont work relibaly if compiled with gcc
tccelf.c/tccpp.c/tccrun.c
Change: "..."+int into &"..."[int] to avoid clang warning.
tests/tcctest.c:
- Change __APPLE__ into __clang__
- Add undefined_function for clang
- disable most asm code for clang
- Fix res6/res8 for __builtin_constant_p
* non-process-shared POSIX semaphores aren't supported on
Darwin, we use the dispatch framework
* dlsym segfaults with RTLD_NEXT from JIT code, so we must not
even try this for -run. So we need to know in __bound_init
if called from -run code, or from normal code, which means passing
this down also from __bt_init and hence from the stub added in
tcc_add_btstub
* Darwin uses different structures for <ctype.h> facilities, this
merely adds a warning about this
* __libc_freeres doesn't exist
* for non -run modus the context (.prog_base member) is constructed
incorrectly (uses symbol zero for trying to get at the load bias,
which doesn't really work that way), on Mach-O this errors out
(and could also error out on ELF). For now deactivate this, which
makes backtraces not be symbolic on MacOS for not -run.
uncovered by the backtrace/boundcheck tests:
* handle STT_SECTION symbols
* call tcc_add_runtime (to get the bcheck.o/bt-exe.o files added)
* add .stab strtab into segments (we should probably add all stab
syms to the output LC_SYMTAB eventually, but right now TCC uses
32 bit stabs, while mach-o uses 32/64bit stabs
for handling leading underscores when looking up symbols.
Necessary on MacOS, as there C symbols have a '_' prepended.
get_sym_addr (replacing get_elf_sym_addr) gets an argument to
specify if bare/raw/ELF symbols should be looked up or if decorated
C symbols should be looked up. That reflects into tcc_get_symbol.
tcc_add_symbol is _not_ yet changed, but probably should be.
all C/C++/ObjC symbols in symbols tables have a leading underscore
in Mach-O. Within TCC there's some confusion with tcc_add_symbol
(not adding it) and tcc_get_elf_symbol (not expecting it), and
resolve_syms (using dlsym, which doesn't expect it) and -run support.
But this sort of works.
this does generate a working executable for a very simple
example input, e.g. this:
% cat simple.c
int main(void)
{
return 0;
}
% ./tcc -B. -c simple.c
% ./tcc -nostdlib -B. simple.o -lc
% ./a.out && echo okay
okay
(the -lc is actually not necessary right now, see below). This
has many limitations:
* no symbol table, hence no calls to external functions from
e.g. libc, aka libSystemB
* no proper entry point (should be main, but is hardcoded to first
real .text address)
* libSystemB is hardcoded, no other libs are supported (but again
no external calls anyway)
* generated Mach-O executable is in old format: neither LC_DYLD_INFO
no export tries for symbols are created (no symbol table at all!)
* the __LINKEDIT segment is faked and empty, as dyld doesn't like
it empty even if no symbols point into it
* same with __DATA, dyld wants a non-empty writable segment which
we enforce with useless data
* no relocations, hence no function call stubs (lazy or not) are
generated
* hardcodes some other constants as well
from e640ed1aeb
Also:
- cleanup -std, -O, -pthread
- tcc.h:win32: use win32-type include paths even for cross
compilers (needed for loading tcc_predefs.h in cases)
- Makefile: simplify OSX .dylib clause
Checked on:
- i386/x86_64 (linux/windows)
- arm/arm64 (rapberry pi)
- riscv64 (simulator)
Not tested for arm softfloat because raspberry pi does not support it.
Modifications:
Makefile:
add arm-asm.c to arm64_FILES
add riscv64-asm.c (new file) to riscv64_FILES
lib/Makefile:
add fetch_and_add_arm.o(new file) to ARM_O
add fetch_and_add_arm64.o(new file) to ARM64_O
add fetch_and_add_riscv64.o(new file) to RISCV64_O
add $(BCHECK_O) to OBJ-arm/OBJ-arm64/OBJ-riscv64
tcc.h:
Enable CONFIG_TCC_BCHECK for arm32/arm64/riscv64
Add arm-asm.c, riscv64-asm.c
tcctok.h:
for arm use memmove4 instead of memcpy4
for arm use memmove8 instead of memcpy8
tccgen.c:
put_extern_sym2: for arm check memcpy/memmove/memset/memmove4/memmove8
only use alloca for i386/x86_64
for arm use memmove4 instead of memcpy4
for arm use memmove8 instead of memcpy8
fix builtin_frame_address/builtin_return_address for arm/riscv64
tccrun.c:
Add riscv64 support
fix rt_getcontext/rt_get_caller_pc for arm
tccelf.c:
tcc_load_dll: Print filename for bad architecture
libtcc.c:
add arm-asm.c/riscv64-asm.c
tcc-doc.texi:
Add arm, arm64, riscv64 support for bound checking
lib/bcheck.c:
add __bound___aeabi_memcpy/__bound___aeabi_memmove
__bound___aeabi_memmove4/__bound___aeabi_memmove8
__bound___aeabi_memset for arm
call fetch_and_add_arm/fetch_and_add_arm64/fetch_and_add_riscv64
__bound_init: Fix type for start/end/ad
__bound_malloc/__bound_memalign/__bound_realloc/__bound_calloc: Use size + 1
arm-gen.c:
add bound checking code like i386/x86_64
assign_regs: only malloc if nb_args != 0
gen_opi/gen_opf: Fix reload problems
arm-link.c:
relocate_plt: Fix address calculating
arm64-gen.c:
add bound checking code like i386/x86_64
load/store: remove VT_BOUNDED from sv->r
arm64_hfa_aux/arm64_hfa_aux: Fix array code
gfunc_prolog: only malloc if n != 0
arm64-link.c:
code_reloc/gotplt_entry_type/relocate: add R_AARCH64_LDST64_ABS_LO12_NC
relocate: Use addXXle instead of writeXXle
riscv64-gen.c:
add bound checking code like i386/x86_64
add NB_ASM_REGS/CONFIG_TCC_ASM
riscv64-link.c:
relocate: Use addXXle instead of writeXXle
i386-gen.c/x86_64-gen.c
gen_bounds_epilog: Fix code (unrelated)
tests/Makefile:
add $(BTESTS) for arm/arm64/riscv64
tests/tests2/Makefile:
Use 85 only on i386/x86_64 because of asm code
Use 113 only on i386/x86_64 because of DLL code
Add 112/114/115/116 for arm/arm64/riscv64
Fix FILTER (failed on riscv64)
tests/boundtest.c:
Only use alloca for i386/x86_64
ELF files that refer to shared libs containing sym-versions, but
don't refer to any dynamic symbols with symbol versions (should happen
only with very simple shared libs) would generate an empty .gnu.version_r
section. Some dynamic linker contain bugs in that they don't check
the section size or DT_VERNEEDNUM (which are both zero for such files
we generate) before accessing the first entry, and then bail out with
a message like
./a.exe: error while loading shared libraries: ./a1.so: unsupported
version 25960 of Verneed record
(where the "version number" actually comes from neighboring bytes
from different sections).
So, there's not much choice, we simply must not generate such section.
- tests2/113_btdll.c: test handling multiple stabs infos
Also:
- libtcc.c: remove _ISOC99_SOURCE pre-defines. It is causing
strange warnings such as 'strdup not declared'
- i386/x86_64-gen.c cleanup bounds_pro/epilog. This discards
the extra code for main's argv. If needed, __argv might be
processed instead.
- tccgen.c:block(): reduce stackspace usage. For example with
code like "if (..) ... else if (..) ... else if (..)... "
considerable numbers of nested block() calls may occur.
Before that most stack space used when compiling itself was
for libtcc.c:tcc_set_linker().
Now it's rather this construct at tccpp.c:2765: in next_nomacro1():
if (!((isidnum_table[c - CH_EOF] & (IS_ID|IS_NUM))
|| c == '.'
|| ((c == '+' || c == '-')
...
This makes it possible to get backtraces with executables
(including DLLs/SOs) like we had it already with -g -run.
Option -b includes -bt, and -bt includes -g.
- new file lib/bt-exe.c: used to link rt_printline and the
exception handler from tccrun.c into executables/DLLs.
- new file lib/bt-log.c: provides a function that may be
called from user code to print out a backtrace with a
message (currently for i386/x86_64 only):
int (*tcc_backtrace)(const char *fmt, ...);
As an extra hack, if 'fmt' is prefixed like "^file.c^..."
then the backtrace will skip calls from within 'file.c'.
- new file lib/bt-dll.c: used on win32 to link the backtrace
and bcheck functions with the main module at runtime
- bcheck.c: now uses the tcc_backtrace function from above
- tccgen.c: minor cleanups
- tccelf.c: stab sections get SHF_ALLOC for easy access.
Also in relocate_section(): 64bit relocations for stabs
in DLLs cannot work. To find DLL addresses, the DLL base
is added manually in tccrun.c via rc.prog_base instead.
- tccpe.c: there are some changes to allow merging sections,
used to merge .finit_array into .data in the first place.
- tccpp.c: tcc -run now #defines __TCC_RUN__
also: refactor a line in tal_realloc that was incompatible
with bcheck
- tcctest.c: fixed a problem with r12 which tcc cannot preserve
as well as gcc does.
- tests2/112_backtrace.c: test the feature and the bcheck test18
that previously was in boundtest.c
Add __attribute__((constructor)) to __bounds_init.
- remove tcc_add_bcheck from i386-link.c and x86_64-link.c
- add simplified tcc_add_bcheck to tccelf.c
- Update tccrun.c to call constructor/destructor.
Set dynsym sh_info to number of local symbols in tccelf.c
Reduce stack size when bounds checking is enabled.
Added variable TCC_LIBBCHECK for windows support.
Add signal stack to detect stack overflow.
Add all & parameters in lbound_section and remove them if not used.
Close fd in tcc_relocate in tccrun.c
Fix section type constructor/destructor in tccelf.c
Add check code in tests/boundtest.c for mem/str functions.
Remove -ba from documentation.
Add bounds check signal info in documentation.
bcheck.c:
- Fix initial_pool alignment.
. Fix printf statements.
. Add prototypes for all external interface functions.
- Add TCC_BOUNDS_WARN_POINTER_ADD environment variable.
. Add ctype and errno data.
- Fix alloca when multithreading is used.
- Add lock for __bound_checking and __bound_never_fatal.
- Catch pthread_create and use locks when called.
- Detect in loaded in shared lib and use locks when found
- Use spin locks instead of semaphore locks.
- Make spin locked code as small as possible.
- Fix mem/str functions checking.
- Fix overlap checking mem/str functions.
Put total_lines etc. into TCCState. Also, initialize
the predefined compiler types for the preprocessor too.
tccpe.c: fix BaseOfCode if .init section present (with tcc -b)
* a major revision of the rt_printline() feature in
tccrun.c to report file:linenumber more correctly.
* minor changes to the stab info produced by the
compiler in tccgen.c
However stab addresses are limited to 32 bits. I added
a work around:
if (sizeof pc == 8)
pc |= wanted_pc & 0xffffffff00000000ULL;
However GDB has problems with that too.
- revert Makefiles to state before last bcheck additions
Instead, just load bcheck.o explicitly if that is
what is wanted.
- move tcc_add_bcheck() to the <target>-link.c files and
remove revently added arguments. This function is to
support tccelf.c with linking, not for tccgen.c to
support compilation.
- remove -ba option: It said:
"-ba Enable better address checking with bounds checker"
Okay, if it is better then to have it is not an option.
- remove va_copy. It is C99 and we try to stay C89 in tinycc
when possible. For example, MS compilers do not have va_copy.
- win64: revert any 'fixes' to alloca
It was correct as it was before, except for bound_checking
where it was not implemented. This should now work too.
- remove parasitic filename:linenum features
Such feature is already present with rt_printline in
tccrun.c. If it doesn't work it can be fixed.
- revert changes to gen_bounded_ptr_add()
gen_bounded_ptr_add() was working as it should before
(mostly). For the sake of simplicity I switched it to
CDECL. Anyway, FASTCALL means SLOWCALL with tinycc.
In exchange you get one addition which is required for
bounds_cnecking function arguments. The important thing
is to check them *BEFORE* they are loaded into registers.
New function gbound_args() does that.
In any case, code instrumentation with the bounds-check
functions as such now seems to work flawlessly again,
which means when they are inserted as NOPs, any code that
tcc can compile, seems to behave just the same as without
them.
What these functions then do when fully enabled, is a
differnt story. I did not touch this.
The bounds checking code has now enabled gen_bounded_ptr_add tests.
This makes the code slower but finds more errors.
I had to correct some things in tcc to make it work.
- Fixed off by one in lib/bcheck.c
- Corrected tccelf.c sym_versions.
- Disabled USE_TAL when using bounds checking.
- Fixed cstr_printf va_start.
- Fixed tests/tests2/46_grep.c off by one error.
- Updated gen_bounded_ptr_add in x86_64-gen.c
- Fixed x86_64-link.c pointer diff.
For gen_vla_alloc now always use alloca call when bounds checking.
Added line/filename in %rax before bound calls to find location of error.
This allows creation of TCCStates and operation with API
calls independently from each other, even from threads.
Frontend (option parsing/libtcc.c) and backend (linker/tccelf.c)
now depend only on the TCCState (s1) argument.
Compilation per se (tccpp.c, tccgen.c) is still using
globals for convenience. There is only one entry point
to this section which is tcc_compile() which is protected
by a semaphore.
There are some hacks involved to avoid too many changes,
as well as some changes in order to avoid too many hacks ;)
The test libtcc_test_mt.c shows the feature. Except this
new file the patch adds 87 lines overall.
so it isn't quadratic in number of symbols. It's still quadratic
in number of lib/version combinations (at library load time the
sym versions are internalized), but that's much less a problem as
in practice only glibc uses sym versioning.
