Commit Graph

41 Commits

Author SHA1 Message Date
grischka
d79e1dee8c backtrace: test with DLLs
- 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 == '-')
        ...
2020-01-19 11:46:07 +01:00
gr
ef42295fe8 tccrun.c: standalone backtraces with -bt[N] or -b
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
2020-01-17 22:58:39 +01:00
herman ten brugge
3877618785 Update bound checking code.
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.
2020-01-15 08:53:19 +01:00
herman ten brugge
269042503e Fix sellinux pointer code in tccrun.
Free all memory on exit in __bound_exit.
2019-12-23 20:23:18 +01:00
grischka
56db092ab7 bcheck cleanup
- 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.
2019-12-14 13:26:18 +01:00
herman ten brugge
87639aae7c Add linenumber filename support for bounds checking. 2019-12-13 13:45:09 +01:00
herman ten brugge
56e70bfa31 Fix bounds checking new functions.
There was a problem with strncpy and strncmp.
Made bound_ptr_add and bound_ptr_indir a little bit faster.
Fix statistic counter types. Change long into long long.
2019-12-13 10:02:20 +01:00
herman ten brugge
39c0ff311d Add new bounds checking functions.
The following functions are now also bounds checked:
memcmp, strncpy, strcmp, strncmp, strcat, strchr, strdup.

Add statistics code for bounds checking functions.
The statistics can be printed by settings environment variable
"TCC_BOUNDS_PRINT_STATISTIC".

Enabled more tests in test/Makefile.
2019-12-12 20:49:35 +01:00
herman ten brugge
4a2e33d160 Update bounds checking.
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.
2019-12-12 12:56:06 +01:00
herman ten brugge
4d297d354c Add bound checking print heap 2019-12-10 19:47:33 +01:00
herman ten brugge
4461f38a9e Fix bounds checking for linux/windows 2019-12-10 08:07:25 +01:00
Larry Doolittle
1b6806e5bb Spelling fixes
Comments only, no change to functionality
2017-09-24 18:03:26 -07:00
grischka
4b3c6e74ab tccgen: nodata_wanted fix, default ONE_SOURCE, etc...
tccgen.c:
  doubles need to be aligned, on ARM.  The section_reserve()
  in init_putv does not do that.
-D ONE_SOURCE: is now the default and not longer needed. Also,
  tcc.h now sets the default native target.  These both make
  compiling tcc simple as "gcc tcc.c -o tcc -ldl" again.
arm-asm.c:
  enable pseudo asm also for inline asm
tests/tests2/Makefile:
  disable bitfield tests except on windows and x86_64
  and don't generate-always
tcc.c:
  fix a loop with -dt on errors
configure:
  print compiler version (as recognized)
tccpp.c:
  actually define symbols for tcc -dt
  clear static variables (needed for -dt or libtcc usage)
96_nodata_wanted.c:
  use __label__ instead of asm
lib/files:
  use native symbols (__i386__ etc.) instead of TCC_TARGET_...
2017-07-23 21:24:11 +02:00
Marc Vertes
0ac29b53dc Add support of musl-libc
The port is functional. Bound checking is not supported yet.
2017-04-20 22:01:50 +02:00
grischka
bb93064d78 makefile: unify cross with native builds
supports building cross compilers on the fly without need
for configure --enable-cross

   $ make cross          # all compilers
   $ make cross-TARGET   # only TARGET-compiler & its libtcc1.a

with TARGET one from
   i386 x86_64 i386-win32 x86_64-win32 arm arm64 arm-wince c67

Type 'make help' for more information
2017-02-25 12:51:04 +01:00
Christian Jullien
ed99f3608d Remove warning when __builtin_frame_address is used with gcc >= 6. 2016-11-30 06:18:48 +01:00
grischka
9c5bb16447 Revert part of "fix installation amd bcheck for Windows"
tccelf.c : force linking bcheck by adding elf symbol __bound_init
bcheck.c : use (size_t)1 for x86_64

Fixes 7e7e6148fd
2016-10-01 20:47:36 +02:00
gus knight
89ad24e7d6 Revert all of my changes to directories & codingstyle. 2015-07-29 16:57:12 -04:00
gus knight
41031221c8 Trim trailing spaces everywhere. 2015-07-27 12:43:40 -04:00
seyko
559675b90a a bounds checking code for the ARCH=x86_64 2015-04-10 15:17:22 +03:00
seyko
7e7e6148fd fix installation amd bcheck for Windows
* define targetos=Windows when --enable-tcc32-mingw, --enable-cygwin, ...
    * use TARGETOS insteed HOST_OS when selecting PROGS
    * use "$(tccdir)" insteed $(tccdir) on install (spaces in path)
    * install tcc.exe too
    * produce bcheck.o when cross-compiling too (lib/Makefile)
    * force bcheck.o linking by compiling inside tcc_set_output_type()
      a dummy program with local array. Otherwise bcheck.o may be not linked.
    * replace %xz format specifier with %p in bcheck (don't supported on
      Windows)
    * call a __bound_init when __bound_ptr_add, __bound_ptr_indir,
      __bound_new_region, __bound_delete_region called.
      This is because a __bound_init inside ".init" section is not called
      on Windows for unknown reason.
    * print on stderr a message when an illegal pointer is returned:
        there is no segmentation violation on Windows for a program
        compiled with "tcc -b"
    * remove "C:" subdir on clean if $HOST_OS = "Linux"
    * default CFLAGS="-Wall -g -O0" insteed CFLAGS="-Wall -g -O2"
      to speed up compilation and more precise debugging.
2015-04-10 07:37:31 +03:00
seyko
96debc72f8 a small revers for bcheck.o changes (d80593bc4d)
replacing (addr > e->size) with (addr >= e->size)
    was correct only in one place, a second replacing
    is reversed by this commit.
2015-03-30 06:15:47 +03:00
seyko
db08122d31 Fix for Microsoft compilers
Miccrosoft Visual Sudio (Express) 2008 and 2010 do not accept variable
    definitions C99 style, reported by Fabio <oldfaber@gmail.com>
2015-03-29 11:52:16 +03:00
seyko
d80593bc4d fix for the bcheck.o (bug #14958)
- care about __attribute__ redefinition in the system headers
    - an invalid pointer must be returned when (addr >= e->size),
      and not (addr > e->size)

    A test program:
    #include <stdio.h>
    #include <stdlib.h>
    int main ()
    {
	int v[10];
	fprintf(stderr, "&v[0]  = %p\n", &v[0]);
	fprintf(stderr, "&v[10] = %p\n", &v[10]);
	exit(1);
	return 0;
    }
    // tcc -b test.c

    The output before a patch:
    &v[0]  = 0xbf929d8c
    &v[10] = 0xbf929db4

    The output after a patch:
    &v[0]  = 0xbff6e33c
    &v[10] = 0xfffffffe
2015-03-29 11:28:02 +03:00
seyko
acef4ff244 make a bound checking more compatible with Windows 64
On Linux 32:   sizeof(long)=32 == sizeof(void *)=32
    on Linux 64:   sizeof(long)=64 == sizeof(void *)=64
    on Windows 64: sizeof(long)=32 != sizeof(void *)=64
2015-03-26 07:47:45 +03:00
seyko
4c8ffb353d remove a gcc warning for bcheck on x86_64 arch: conversion to pointer from integer of different size 2015-03-03 16:18:24 +03:00
minux
9714d2e75f build: add initial NetBSD support.
Not able to generate ELF files on NetBSD yet (lacks the note and crt1.o
is actually named crt0.o on NetBSD), but -run works with these extra
defines:
-D__lint__ -D"__symbolrename(x)=asm(#x)" -D__NetBSD__

The -D__lint__ is an ugly hack, TCC should be able to emulate GCC just
fine, but it seems TCC doesn't support __builtin_va_list yet?
	typedef __builtin_va_list __va_list;
/usr/include/sys/ansi.h:72: error: ';' expected (got "__va_list")
2014-04-12 01:42:46 -04:00
Vincent Lefevre
3e9a7e9d69 Corrected spelling mistakes in comments and strings 2014-04-07 13:31:00 +02:00
Thomas Preud'homme
b125743323 Create bcheck region for argv and arge argument
For program manipulating argv or arge as pointer with construct such as:

(while *argv++) {
  do_something_with_argv;
}

it is necessary to have argv and arge inside a region. This patch create
regions argv and arge) if main is declared with those parameters.
2014-03-29 14:46:26 +08:00
Urs Janssen
0bdbd49eac add version number to manpage
avoid c++/c99 style comments in preprocessor directives
avoid leadings whitespaces in preprocessor directives
mention implemented variable length arrays in documentation
fixed ambiguous option in texi2html call (Austin English)
2013-02-17 00:48:51 +01:00
grischka
7a477d70ca lib/Makefile: use CC, add bcheck to libtcc1.a
Also:
- fix "make tcc_p" (profiling version)
- remove old gcc flags:
  -mpreferred-stack-boundary=2 -march=i386 -falign-functions=0
- remove test "hello" for Darwin (cannot compile to file)
2013-02-06 19:01:07 +01:00
Roy
d815896d4c bcheck: there is no unistd.h in win32. 2012-12-10 09:51:49 +08:00
Kirill Smelkov
dbeb4faf21 lib/bcheck: Fix code typo in __bound_delete_region()
We were calling get_page() with t2 index which is not correct, since
get_page() operate on t1 indices. The bug is here from day-1, from
60f781c4 (first version of bounds checker) and show as a crash in
__bound_delete_region() at program exit:

    $ ./tcc   -B. -DTCC_TARGET_I386 -DCONFIG_MULTIARCHDIR=\"i386-linux-gnu\" -b -run -DONE_SOURCE \
      ./tcc.c -B. -DTCC_TARGET_I386 -DCONFIG_MULTIARCHDIR=\"i386-linux-gnu\"    -run -DONE_SOURCE \
      ./tcc.c -B. -run tests/tcctest.c

    (lot's of correct output from tcctest)
    Runtime error: dereferencing invalid pointer
    at 0xa7c21cc4 __bound_delete_region()
    by (nil) ???
    Segmentation fault

The fix is simple - last page should be get through t1_end, like it is
done in __bound_new_region().

After this patch, tcc is being able to compile itself with -b, then
compile itself again and run tcctest with correct output. Tests follow.
2012-12-09 19:33:47 +04:00
Kirill Smelkov
efd9d92b7c lib/bcheck: Don't assume heap goes right after bss
At startup __bound_init() wants to mark malloc zone as invalid memory,
so that any access to memory on heap, not allocated through malloc be
invalid. Other pages are initialized as empty regions, access to which
is not treated as invalid by bounds-checking.

The problem is code incorrectly assumed that heap goes right after bss,
and that is not correct for two cases:

    1) if we are running from `tcc -b -run`, program text data and bss
       will be already in malloced memory, possibly in mmaped region
       insead of heap, and marking memory as invalid from _end
       will not cover heap and probably wrongly mark correct regions.

    2) if address space randomization is turned on, again heap does not
       start from _end, and we'll mark as invalid something else instead
       of malloc area.

For example with the following diagnostic patch ...

    diff --git a/tcc.c b/tcc.c
    index 5dd5725..31c46e8 100644
    --- a/tcc.c
    +++ b/tcc.c
    @@ -479,6 +479,8 @@ static int parse_args(TCCState *s, int argc, char **argv)
         return optind;
     }

    +extern int _etext, _edata, _end;
    +
     int main(int argc, char **argv)
     {
         int i;
    @@ -487,6 +489,18 @@ int main(int argc, char **argv)
         int64_t start_time = 0;
         const char *default_file = NULL;

    +    void *brk;
    +
    +    brk = sbrk(0);
    +
    +    fprintf(stderr, "\n>>> TCC\n\n");
    +    fprintf(stderr, "etext:\t%10p\n",  &_etext);
    +    fprintf(stderr, "edata:\t%10p\n",  &_edata);
    +    fprintf(stderr, "end:\t%10p\n",    &_end);
    +    fprintf(stderr, "brk:\t%10p\n",    brk);
    +    fprintf(stderr, "stack:\t%10p\n",  &brk);
    +
    +    fprintf(stderr, "&errno: %p\n", &errno);
         s = tcc_new();

         output_type = TCC_OUTPUT_EXE;

    diff --git a/tccrun.c b/tccrun.c
    index 531f46a..25ed30a 100644
    --- a/tccrun.c
    +++ b/tccrun.c
    @@ -91,6 +91,8 @@ LIBTCCAPI int tcc_run(TCCState *s1, int argc, char **argv)
         int (*prog_main)(int, char **);
         int ret;

    +    fprintf(stderr, "\n\ntcc_run() ...\n\n");
    +
         if (tcc_relocate(s1, TCC_RELOCATE_AUTO) < 0)
             return -1;

    diff --git a/lib/bcheck.c b/lib/bcheck.c
    index ea5b233..8b26a5f 100644
    --- a/lib/bcheck.c
    +++ b/lib/bcheck.c
    @@ -296,6 +326,8 @@ static void mark_invalid(unsigned long addr, unsigned long size)
         start = addr;
         end = addr + size;

    +    fprintf(stderr, "mark_invalid  %10p - %10p\n", (void *)addr, (void *)end);
    +
         t2_start = (start + BOUND_T3_SIZE - 1) >> BOUND_T3_BITS;
         if (end != 0)
             t2_end = end >> BOUND_T3_BITS;

... Look how memory is laid out for `tcc -b -run ...`:

    $ ./tcc -B. -b -DTCC_TARGET_I386 -DCONFIG_MULTIARCHDIR=\"i386-linux-gnu\"  -run   \
        -DONE_SOURCE ./tcc.c -B. -c x.c

    >>> TCC

    etext:   0x8065477
    edata:   0x8070220
    end:     0x807a95c
    brk:     0x807b000
    stack:  0xaffff0f0
    &errno: 0xa7e25688

    tcc_run() ...

    mark_invalid  0xfff80000 -      (nil)
    mark_invalid  0xa7c31d98 - 0xafc31d98

    >>> TCC

    etext:  0xa7c22767
    edata:  0xa7c2759c
    end:    0xa7c31d98
    brk:     0x8211000
    stack:  0xafffeff0
    &errno: 0xa7e25688
    Runtime error: dereferencing invalid pointer
    ./tccpp.c:1953: at 0xa7beebdf parse_number() (included from ./libtcc.c, ./tcc.c)
    ./tccpp.c:3003: by 0xa7bf0708 next() (included from ./libtcc.c, ./tcc.c)
    ./tccgen.c:4465: by 0xa7bfe348 block() (included from ./libtcc.c, ./tcc.c)
    ./tccgen.c:4440: by 0xa7bfe212 block() (included from ./libtcc.c, ./tcc.c)
    ./tccgen.c:5529: by 0xa7c01929 gen_function() (included from ./libtcc.c, ./tcc.c)
    ./tccgen.c:5767: by 0xa7c02602 decl0() (included from ./libtcc.c, ./tcc.c)

The second mark_invalid goes right after in-memory-compiled program's
_end, and oops, that's not where malloc zone is (starts from brk), and oops
again, mark_invalid covers e.g. errno. Then compiled tcc is crasshing by
bcheck on errno access:

    1776 static void parse_number(const char *p)
    1777 {
    1778     int b, t, shift, frac_bits, s, exp_val, ch;
         ...
    1951             *q = '\0';
    1952             t = toup(ch);
    1953             errno = 0;

The solution here is to use sbrk(0) as approximation for the program
break start instead of &_end:

    - if we are a separately compiled program, __bound_init() runs early,
      and sbrk(0) should be equal or very near to start_brk (in case other
      constructors malloc something), or

    - if we are running from under `tcc -b -run`, sbrk(0) will return
      start of heap portion which is under this program control, and not
      mark as invalid earlier allocated memory.

With this patch `tcc -b -run tcc.c ...` succeeds compiling above
small-test program (diagnostic patch is still applied too):

    $ ./tcc -B. -b -DTCC_TARGET_I386 -DCONFIG_MULTIARCHDIR=\"i386-linux-gnu\"  -run   \
        -DONE_SOURCE ./tcc.c -B. -c x.c

    >>> TCC

    etext:   0x8065477
    edata:   0x8070220
    end:     0x807a95c
    brk:     0x807b000
    stack:  0xaffff0f0
    &errno: 0xa7e25688

    tcc_run() ...

    mark_invalid  0xfff80000 -      (nil)
    mark_invalid   0x8211000 - 0x10211000

    >>> TCC

    etext:  0xa7c22777
    edata:  0xa7c275ac
    end:    0xa7c31da8
    brk:     0x8211000
    stack:  0xafffeff0
    &errno: 0xa7e25688

    (completes ok)

but running `tcc -b -run tcc.c -run tests/tcctest.c` sigsegv's - that's
the plot for the next patch.
2012-12-09 19:05:36 +04:00
Kirill Smelkov
cffb7af9f9 lib/bcheck: Prevent __bound_local_new / __bound_local_delete from being miscompiled
On i386 and gcc-4.7 I found that __bound_local_new was miscompiled -
look:

    #ifdef __i386__
    /* return the frame pointer of the caller */
    #define GET_CALLER_FP(fp)\
    {\
        unsigned long *fp1;\
        __asm__ __volatile__ ("movl %%ebp,%0" :"=g" (fp1));\
        fp = fp1[0];\
    }
    #endif

    /* called when entering a function to add all the local regions */
    void FASTCALL __bound_local_new(void *p1)
    {
        unsigned long addr, size, fp, *p = p1;
        GET_CALLER_FP(fp);
        for(;;) {
            addr = p[0];
            if (addr == 0)
                break;
            addr += fp;
            size = p[1];
            p += 2;
            __bound_new_region((void *)addr, size);
        }
    }

    __bound_local_new:
    .LFB40:
            .cfi_startproc
            pushl   %esi
            .cfi_def_cfa_offset 8
            .cfi_offset 6, -8
            pushl   %ebx
            .cfi_def_cfa_offset 12
            .cfi_offset 3, -12
            subl    $8, %esp            // NOTE prologue does not touch %ebp
            .cfi_def_cfa_offset 20
    #APP
    # 235 "lib/bcheck.c" 1
            movl %ebp,%edx              // %ebp -> fp1
    # 0 "" 2
    #NO_APP
            movl    (%edx), %esi        // fp1[0] -> fp
            movl    (%eax), %edx
            movl    %eax, %ebx
            testl   %edx, %edx
            je      .L167
            .p2align 2,,3
    .L173:
            movl    4(%ebx), %eax
            addl    $8, %ebx
            movl    %eax, 4(%esp)
            addl    %esi, %edx
            movl    %edx, (%esp)
            call    __bound_new_region
            movl    (%ebx), %edx
            testl   %edx, %edx
            jne     .L173
    .L167:
            addl    $8, %esp
            .cfi_def_cfa_offset 12
            popl    %ebx
            .cfi_restore 3
            .cfi_def_cfa_offset 8
            popl    %esi
            .cfi_restore 6
            .cfi_def_cfa_offset 4
            ret

here GET_CALLER_FP() assumed that its using function setups it's stack
frame, i.e. first save, then set %ebp to stack frame start, and then it
has to do perform two lookups: 1) to get current stack frame through
%ebp, and 2) get caller stack frame through (%ebp).

And here is the problem: gcc decided not to setup %ebp for
__bound_local_new and in such case GET_CALLER_FP actually becomes
GET_CALLER_CALLER_FP and oops, wrong regions are registered in bcheck
tables...

The solution is to stop using hand written assembly and rely on gcc's
__builtin_frame_address(1) to get callers frame stack(*). I think for the
builtin gcc should generate correct code, independent of whether it
decides or not to omit frame pointer in using function - it knows it.

(*) judging by gcc history, __builtin_frame_address was there almost
    from the beginning - at least it is present in 1992 as seen from the
    following commit:

    http://gcc.gnu.org/git/?p=gcc.git;a=commit;h=be07f7bdbac76d87d3006c89855491504d5d6202

    so we can rely on it being supported by all versions of gcc.

In my environment the assembly of __bound_local_new changes as follows:

    diff --git a/bcheck0.s b/bcheck1.s
    index 4c02a5f..ef68918 100644
    --- a/bcheck0.s
    +++ b/bcheck1.s
    @@ -1409,20 +1409,17 @@ __bound_init:
     __bound_local_new:
     .LFB40:
            .cfi_startproc
    -       pushl   %esi
    +       pushl   %ebp                // NOTE prologue saves %ebp ...
            .cfi_def_cfa_offset 8
    -       .cfi_offset 6, -8
    +       .cfi_offset 5, -8
    +       movl    %esp, %ebp          // ... and reset it to local stack frame
    +       .cfi_def_cfa_register 5
    +       pushl   %esi
            pushl   %ebx
    -       .cfi_def_cfa_offset 12
    -       .cfi_offset 3, -12
            subl    $8, %esp
    -       .cfi_def_cfa_offset 20
    -#APP
    -# 235 "lib/bcheck.c" 1
    -       movl %ebp,%edx
    -# 0 "" 2
    -#NO_APP
    -       movl    (%edx), %esi
    +       .cfi_offset 6, -12
    +       .cfi_offset 3, -16
    +       movl    0(%ebp), %esi       // stkframe -> stkframe.parent -> fp
            movl    (%eax), %edx
            movl    %eax, %ebx
            testl   %edx, %edx
    @@ -1440,13 +1437,13 @@ __bound_local_new:
            jne     .L173
     .L167:
            addl    $8, %esp
    -       .cfi_def_cfa_offset 12
            popl    %ebx
            .cfi_restore 3
    -       .cfi_def_cfa_offset 8
            popl    %esi
            .cfi_restore 6
    -       .cfi_def_cfa_offset 4
    +       popl    %ebp
    +       .cfi_restore 5
    +       .cfi_def_cfa 4, 4
            ret
            .cfi_endproc

i.e. now it compiles correctly.

Though I do not have x86_64 to test, my guess is that
__builtin_frame_address(1) should work there too. If not - please revert
only x86_64 part of the patch. Thanks.

Cc: Michael Matz <matz@suse.de>
2012-11-13 22:17:58 +04:00
Kirill Smelkov
646b51833f lib/bcheck: Prevent libc_malloc/libc_free etc from being miscompiled
On i386 and gcc-4.7 I found that libc_malloc was miscompiled - look:

static void *libc_malloc(size_t size)
{
    void *ptr;
    restore_malloc_hooks();     // __malloc_hook = saved_malloc_hook
    ptr = malloc(size);
    install_malloc_hooks();     // saved_malloc_hook = __malloc_hook, __malloc_hook = __bound_malloc
    return ptr;
}

	.type	libc_malloc, @function
libc_malloc:
.LFB56:
	.cfi_startproc
	pushl	%edx
	.cfi_def_cfa_offset 8
	movl	%eax, (%esp)
	call	malloc
	movl	$__bound_malloc, __malloc_hook
	movl	$__bound_free, __free_hook
	movl	$__bound_realloc, __realloc_hook
	movl	$__bound_memalign, __memalign_hook
	popl	%ecx
	.cfi_def_cfa_offset 4
	ret

Here gcc inlined both restore_malloc_hooks() and install_malloc_hooks()
and decided that

    saved_malloc_hook -> __malloc_hook -> saved_malloc_hook

stores are not needed and could be ommitted. Only it did not know
__molloc_hook affects malloc()...

So add compiler barrier to both install and restore hooks functions and
be done with it - the code is now ok:

    diff --git a/bcheck0.s b/bcheck1.s
    index 5f50293..4c02a5f 100644
    --- a/bcheck0.s
    +++ b/bcheck1.s
    @@ -42,8 +42,24 @@ libc_malloc:
            .cfi_startproc
            pushl   %edx
            .cfi_def_cfa_offset 8
    +       movl    saved_malloc_hook, %edx
    +       movl    %edx, __malloc_hook
    +       movl    saved_free_hook, %edx
    +       movl    %edx, __free_hook
    +       movl    saved_realloc_hook, %edx
    +       movl    %edx, __realloc_hook
    +       movl    saved_memalign_hook, %edx
    +       movl    %edx, __memalign_hook
            movl    %eax, (%esp)
            call    malloc
    +       movl    __malloc_hook, %edx
    +       movl    %edx, saved_malloc_hook
    +       movl    __free_hook, %edx
    +       movl    %edx, saved_free_hook
    +       movl    __realloc_hook, %edx
    +       movl    %edx, saved_realloc_hook
    +       movl    __memalign_hook, %edx
    +       movl    %edx, saved_memalign_hook
            movl    $__bound_malloc, __malloc_hook
            movl    $__bound_free, __free_hook
            movl    $__bound_realloc, __realloc_hook

For barrier I use

    __asm__ __volatile__ ("": : : "memory")

which is used as compiler barrier by Linux kernel, and mentioned in gcc
docs and in wikipedia [1].

Without this patch any program compiled with tcc -b crashes in startup
because of infinite recursion in libc_malloc.

[1] http://en.wikipedia.org/wiki/Memory_ordering#Compiler_memory_barrier
2012-11-13 22:17:51 +04:00
Michael Matz
b068e29df7 x86_64: Implement GET_CALLER_FP
TCC always uses %rbp frames, so we can use that one.
2012-04-18 20:57:13 +02:00
Thomas Preud'homme
776364f395 Add support for __FreeBSD_kernel__ kernel
Add support for kfreebsd-i386 and kfreebsd-amd64 Debian arch with
thanks to Pierre Chifflier <chifflier@cpe.fr>.
2010-09-10 21:09:07 +02:00
grischka
7fa712e00c win32: enable bounds checker & exception handler
exception handler borrowed from k1w1. Thanks.
2009-12-19 22:22:43 +01:00
grischka
0085c648f6 bcheck: restore malloc hooks when done 2009-07-18 21:54:47 +02:00
grischka
ea5e81bd6a new subdirs: include, lib, tests 2009-04-18 15:08:03 +02:00