A test program (must be compiled by the above version of the tcc):
/* Tickle a bug in TinyC on 64-bit systems:
* the LSB of the top word or ARGP gets set
* for no obvious reason.
*
* Source: a legacy language interpreter which
* has a little stack / stack pointer for arguments.
*
* Output is: 0x8049620 0x10804961c
* Should be: 0x8049620 0x804961c
*/
#include <stdio.h>
#define NARGS 20000
int ARG[NARGS];
int *ARGSPACE = ARG;
int *ARGP = ARG - 1;
main() { printf("%p %p\n", ARGSPACE, ARGP); }
The common code to move a returned structure packed into
registers into memory on the caller side didn't take the
register size into account when allocating local storage,
so sometimes that lead to stack overwrites (e.g. in 73_arm64.c),
on x86_64. This fixes it by generally making gfunc_sret also return
the register size.
__clear_cache is defined in lib-arm64.c with a single call to
__arm64_clear_cache, which is the real built-in function and is
turned into inline assembler by gen_clear_cache in arm64-gen.c
arm-gen.c: In function `gfunc_call':
arm-gen.c:1202: warning: unused variable `variadic'
arm-gen.c: In function `gfunc_prolog':
arm-gen.c:1258: warning: unused variable `avregs'
arm-gen.c:1340: warning: label `from_stack' defined but not used
arm-gen.c:222: warning: 'default_elfinterp' defined but not used
With this option on a defines are included into the output
(inside comments). This will allow to debug a problems like:
In file included from math.c:8:
In file included from /usr/include/math.h:43:
/usr/include/bits/nan.h:52: warning: NAN redefined
tcc -E -P
do not output a #line directive, a gcc compatible option
tcc -E -P1
don't follow a gcc preprocessor style and do output a standard
#line directive. In such case we don't lose a location info when
we going to compile a resulting file wtith a compiler not
understanding a gnu style line info.
libtcc.c: Add greloca, a generalisation of greloc that takes an addend.
tcc.h: Add greloca and put_elf_reloca.
tccelf.c: Add put_elf_reloca, a generalisation of put_elf_reloc.
tccgen.c: On x86_64, use greloca instead of greloc in init_putv.
This adds parsing of (GCC compatible) visibility attribute
in order to mark selected global symbols as hidden. The generated
.o files contain hidden symbols already, the TCC linker doesn't
yet do the right thing.
Same as with x86_64, disable the runtime_plt_and_got hack
for -run on arm as well. For that we need to handle several
relocations as (potentially) generating PLT slots as well.
Tested with mpfr-3.1.2 and gawk (both using --disable-shared),
there are two resp. five pre-existing problems, so no regressions.
This also works toward enabling real shared libs for arm,
but it's not there yet.
This makes us use the normal PLT/GOT codepaths also for -run,
which formerly used an on-the-side blob for the jump tables.
For x86_64 only for now, arm coming up.
This was going wrong (case TOK_LAND in unary: computed labels)
- vset(&s->type, VT_CONST | VT_SYM, 0);
- vtop->sym = s;
This does the right thing and is shorter:
+ vpushsym(&s->type, s);
Test case was:
int main(int argc, char **argv)
{
int x;
static void *label_return = &&lbl_return;
printf("label_return = %p\n", label_return);
goto *label_return; //<<<<< here segfault on linux X86_64 without the memset on vset
printf("unreachable\n");
lbl_return:
return 0;
}
Also::
- Rename "void* CValue.ptr" to more usable "addr_t ptr_offset"
and start to use it in obvious cases.
- use __attribute__ ((noreturn)) only with gnu compiler
- Revert CValue memsets ("After several days searching ...")
commit 4bc83ac393
Doesn't mean that the vsetX/vpush thingy isn't brittle and
there still might be bugs as to differences in how the CValue
union was set and is then interpreted later on.
However the big memset hammer was just too slow (-3% overall).
This correctly resolves local references to global functions from
shared libs to their PLT slot (instead of directly to the target
symbol), so that interposition works.
This is still not 100% conforming (executables don't export symbols
that are also defined in linked shared libs, as they must), but
normal shared lib situations work.
Introduce a new attribute to check the existence of a PLT entry for a
given symbol has the presence of an entry for that symbol in the dynsym
section is not proof that a PLT entry exists.
This fixes commit dc8ea93b13.
When checking for exact compatibility between types (such as in
__builtin_types_compatible_p) consider the case of default signedness to
be incompatible with both of the explicit signedness for char. That is,
char is incompatible with signed char *and* unsigned char, no matter
what the default signedness for char is.
Refactoring (no logical changes):
- use memcpy in tccgen.c:ieee_finite(double d)
- use union to store attribute flags in Sym
Makefile: "CFLAGS+=-fno-strict-aliasing" basically not necessary
anymore but I left it for now because gcc sometimes behaves
unexpectedly without.
Also:
- configure: back to mode 100755
- tcc.h: remove unused variables tdata/tbss_section
- x86_64-gen.c: adjust gfunc_sret for prototype
- tccgen: error out for cast to void, as in
void foo(void) { return 1; }
This avoids an assertion failure in x86_64-gen.c, also.
also fix tests2/03_struct.c accordingly
- Error: "memory full" - be more specific
- Makefiles: remove circular dependencies, lookup tcctest.c from VPATH
- tcc.h: cleanup lib, include, crt and libgcc search paths"
avoid duplication or trailing slashes with no CONFIG_MULTIARCHDIR
(as from 9382d6f1a0)
- tcc.h: remove ";{B}" from PE search path
in ce5e12c2f9 James Lyon wrote:
"... I'm not sure this is the right way to fix this problem."
And the answer is: No, please. (copying libtcc1.a for tests instead)
- win32/build_tcc.bat: do not move away a versioned file
The procedure calling standard for ARM architecture mandate the use of
the base standard for variadic function. Therefore, hgen float aggregate
must be returned via stack when greater than 4 bytes and via core
registers else in case of variadic function.
This patch improve gfunc_sret() to take into account whether the
function is variadic or not and make use of gfunc_sret() return value to
determine whether to pass a structure via stack in gfunc_prolog(). It
also take advantage of knowing if a function is variadic or not move
float result value from VFP register to core register in gfunc_epilog().
Commit 9382d6f1 ("Fix lib, include, crt and libgcc search paths",
07-09-2013) inadvertently included an initial empty entry to the
CONFIG_TCC_SYSINCLUDEPATHS variable (for non win32 targets). In
addition to an empty line in the 'tcc -vv' display, this leads
to the preprocessor attempting to read an include file from the
root of the filesystem (i.e. '/header.h').
Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Use one more bit in AttributeDef to differenciate between declared
function (only its prototype is known) and defined function (its body is
also known). This allows to generate an error in cases like:
int f(){return 0;}
int f(){return 1;}
- Use runtime function for conversion
- Also initialize fp with tcc -run on windows
This fixes a bug where
double x = 1.0;
double y = 1.0000000000000001;
double z = x < y ? 0 : sqrt (x*x - y*y);
caused a bad sqrt because rounding precision for the x < y comparison
was different to the one used within the sqrt function.
This also fixes a bug where
printf("%d, %d", (int)pow(10, 2), (int)pow(10, 2));
would print
100, 99
Unrelated:
win32: document relative include & lib lookup
win32: normalize_slashes: do not mirror silly gcc behavior
This reverts part of commit 8a81f9e103
winapi: add missing WINAPI decl. for some functions
VLA storage is now freed when it goes out of scope. This makes it
possible to use a VLA inside a loop without consuming an unlimited
amount of memory.
Combining VLAs with alloca() should work as in GCC - when a VLA is
freed, memory allocated by alloca() after the VLA was created is also
freed. There are some exceptions to this rule when using goto: if a VLA
is in scope at the goto, jumping to a label will reset the stack pointer
to where it was immediately after the last VLA was created prior to the
label, or to what it was before the first VLA was created if the label
is outside the scope of any VLA. This means that in some cases combining
alloca() and VLAs will free alloca() memory where GCC would not.
All tests pass. I think I've caught all the cases assuming only XMM0 is
used. I expect that Win64 is horribly broken by this point though,
because I haven't altered it to cope with XMM1.
There are probably still issues on x86-64 I've missed.
I've added a few new tests to abitest, which fail (2x long long and 2x double
in a struct should be passed in registers).
abitest now passes; however test1-3 fail in init_test. All other tests
pass. I need to re-test Win32 and Linux-x86.
I've added a dummy implementation of gfunc_sret to c67-gen.c so it
should now compile, and I think it should behave as before I created
gfunc_sret.
I expect that Linux-x86 is probably fine. All other architectures
except ARM are definitely broken since I haven't yet implemented
gfunc_sret for these, although replicating the current behaviour
should be straightforward.
Only one test so far, which fails on Windows (with MinGW as the native
compiler - I've tested the MinGW output against MSVC and it appears the
two are compatible).
I've also had to modify tcc.h so that tcc_set_lib_path can point to the
directory containing libtcc1.a on Windows to make the libtcc dependent
tests work. I'm not sure this is the right way to fix this problem.
- except for CONFIG_SYSROOT and CONFIG_TCCDIR
Strictly neccessary it is only for CONFIG_MULTIARCHDIR
because otherwise if it's in config.h it is impossible to
leave it undefined.
But it is also nicer not to use these definitions for
cross-compilers.
- Also:
lib/Makefile : include ../Makefile for CFLAGS
lib/libtcc1.c : fix an issue compiling tcc with tcc on x64
- add quotes: eval opt=\"$opt\"
- use $source_path/conftest.c for OOT build
- add fn_makelink() for OOT build
- do not check lddir etc. on Windows/MSYS
- formatting
config-print.c
- rename to conftest.c (for consistency)
- change option e to b
- change output from that from "yes" to "no"
- remove inttypes.h dependency
- simpify version output
Makefile:
- improve GCC warning flag checks
tcc.h:
- add back default CONFIG_LDDIR
- add default CONFIG_TCCDIR also (just for fun)
tccpp.c:
- fix Christian's last warning
tccpp.c: In function ‘macro_subst’:
tccpp.c:2803:12: warning: ‘*((void *)&cval+4)’ is used uninitialized
in this function [-Wuninitialized]
That the change fixes the warning doesn't make sense but anyway.
libtcc.c:
- tcc_error/warning: print correct source filename/line for
token :paste: (also inline :asm:)
lddir and multiarch logic still needs fixing.
This replaces -> use instead:
-----------------------------------
- tcc_set_linker -> tcc_set_options(s, "-Wl,...");
- tcc_set_warning -> tcc_set_options(s, "-W...");
- tcc_enable_debug -> tcc_set_options(s, "-g");
parse_args is moved to libtcc.c (now tcc_parse_args).
Also some cleanups:
- reorder TCCState members
- add some comments here and there
- do not use argv's directly, make string copies
- use const char* in tcc_set_linker
- tccpe: use fd instead of fp
tested with -D MEM_DEBUG: 0 bytes left
tests/Makefile:
- print-search-dirs when 'hello' fails
- split off hello-run
win32/include/_mingw.h:
- fix for compatibility with mingw headers
(While our headers in win32 are from mingw-64 and don't have
the problem)
tiny_libmaker:
- don't use "dangerous" mktemp
Should fix some warnings wrt. access out of array bounds.
tccelf.c: fix "static function unused" warning
x86_64-gen.c: fix "ctype.ref uninitialzed" warning and cleanup
tcc-win32.txt: remove obsolete limitation notes.
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)
This reverts commit 63193d1794.
Had some problems (_STATIC_ASSERT) and was too ugly anyway.
For retry, I'd suggest to implement a general function
static inline void memswap (void *p1, void* p2, size_t n);
and then use that. If you do so, please keep the original code
as comment.
This replaces commit 3d409b0889
- revert old fix in libtcc.c
- #include_next: look up the file in the include stack to see
if it is already included.
Also:
- streamline include code
- remove 'type' from struct CachedInclude (obsolete because we check
full filename anyway)
- remove inc_type & inc_filename from struct Bufferedfile (obsolete)
- fix bug with TOK_FLAG_ENDIF not being reset
- unrelated: get rid of an 'variable potentially uninitialized' warning
Hello up there. On the list Grischka made a point that we can't recommend using
-b as long as tcc -b tcc.c doesn't produce anything useful. Now it does, so
please don't treat -b mode as second class citizen anymore.
Thanks,
Kirill
* bcheck2:
tests: Add tests for compile/run tcc.c with `tcc -b` then compile tcc.c again, then run tcctest.c
lib/bcheck: Fix code typo in __bound_delete_region()
lib/bcheck: Don't assume heap goes right after bss
Make tcc work after self-compiling with bounds-check enabled
For vstack Fabrice used the trick to initialize vtop to &vstack[-1], so
that on first push, vtop becomes &vstack[0] and a value is also stored
there - everything works.
Except that when tcc is compiled with bounds-checking enabled, vstack - 1
returns INVALID_POINTER and oops...
Let's workaround it with artificial 1 vstack slot which will not be
used, but only serve as an indicator that pointing to &vstack[-1] is ok.
Now, tcc, after being self-compiled with -b works:
$ ./tcc -B. -o tccb -DONE_SOURCE -DCONFIG_MULTIARCHDIR=\"i386-linux-gnu\" tcc.c -ldl
$ cd tests
$ ../tcc -B.. -run tcctest.c >1
$ ../tccb -B.. -run tcctest.c >2
$ diff -u 1 2
and note, tcc's compilation speed is not affected:
$ ./tcc -B. -bench -DONE_SOURCE -DCONFIG_MULTIARCHDIR=\"i386-linux-gnu\" -c tcc.c
before: 8270 idents, 47221 lines, 1527730 bytes, 0.152 s, 309800 lines/s, 10.0 MB/s
after: 8271 idents, 47221 lines, 1527733 bytes, 0.152 s, 310107 lines/s, 10.0 MB/s
But note, that `tcc -b -run tcc` is still broken - for example it crashes
on
$ cat x.c
double get100 () { return 100.0; }
$ ./tcc -B. -b -DTCC_TARGET_I386 -DCONFIG_MULTIARCHDIR=\"i386-linux-gnu\" -run \
-DONE_SOURCE ./tcc.c -B. -c x.c
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)
that's because lib/bcheck.c runtime needs more fixes -- see next
patches.
Revert commit 891dfcdf3f since it assumes
*all* architectures supported by tcc have GOT offsets aligned on 2. A
rework of this commit is being done since without it all PLT entries
grow by 4 bytes.
Generate PLT thumb stub for an ARM PLT entry only when at least one
Thumb instruction branches to that entry.
Warning: To save space, this commit reuses the bit 0 of entries of
got_offsets array. The GOT offset is thus saved in a 31 bit value.
Make sure to divide by 2 (right shift by 1) an offset before storing it
there and conversely to multiply the value by 2 (left shift by 1) before
using it.
Introduce ARM version for the target architecture in order to determine
if blx instruction can be used or not. Availability of blx instruction
allows for more scenarii supported in R_ARM_CALL relocation. It should
also be useful when introducing support for the R_ARM_THM_CALL
relocation.
* Add multiarch directories for arm and i386
* Fix detection of biarch: /lib64/ld-linux-x86-64.so.2 is mandated by
ABI and is thus always present, even if there is no biarch
* Define CONFIG_LDDIR directly with the right value in case of multiarch
instead of defining it to /lib and then redifining it.
This patch fix 2 bugs in CONFIG_LDDIR usage:
* CONFIG_LDDIR used for 2 purposes
there is confusion between the directory to find libraries, crt* files
and headers and the directory in which the program interpreter is.
These two directories are not related. The latter is specified by the
ABI and should not be configurable while the former depends on the
system (single arch, biarch, multiarch). This end a longstanding issue
with amd64 program interpreter later propagated to other architecture
interpreters.
* If multiarch is in effect, then the library directory should be /lib.
/lib64 denotes biarch architecture, everything which is here would be
in /lib/x86_64-linux-gnu instead.
This matters when sizeof is directly used in arithmetic,
ala "uintptr_t t; t &= -sizeof(long)" (for alignment). When sizeof
isn't size_t (as it's specified to be) this masking will truncate
the high bits of the uintptr_t object (if uintptr_t is larger than
uint).
- tests/Makefile:
fix commit de54586d5b
This hunk it unrelated to the other changes (which are about MacOSX).
It is not useful and partially wrong. Optional tests are meant to
stay optional, btest would work only for i386
- tcc.h:
fix commit c52d79605a by unknown
The message says it's for MINTW but the patch has obviously
no effect for MINGW (which defines __GNUC__). However the patch
seems useful for MSC which however needs _strto(u)i64 with underscore.
- Makefile:
fix commit 5280293d6b
Do not build tcc.o with -DONE_SOURCE because we finally build tcc
from tcc.o and libtcc.a/so
- remove redunant else branch
- zero-terminate linker_arg
- declare cstr_xxx as PUB_FUNC
(which are functions used in tcc.c but not in the libtcc API.
Useful for a tcc(.exe) that uses the libtcc.(so/dll))
- while at it, export PUB_FUNCs from dll
See also commit 9527c4949f
On x86_64 we need to extend the reg_classes array because load()
is called for (at least) R11 too, which was not part of reg_classes
previously.
Modify tcc to accept convert full 64bits of specified text section
when converting on Win64. Write high bytes to the elf section address
as well. This allows creation of elf binaries located in offsets using
full 64 bit addresses.
Signed-off-by: Andrew Mulbrook <andrew262@gmail.com>
This changeset attempts to fix a few problems when giving using
the high 32bits of a 64bit section offset. There are likely more
issues (or perhaps regressions) lurking in the muck here. In general,
this moves a few data type declarations to use uplong. Also, add
support for 64bit mingw32 building under cygwin. Because native
types are used for 64 bit offsets, this won't fix challenges with
cross compiling from 32bit -> 64bit.
Tested under cygwin, against binary compiled with
-Wl,-Ttext=0xffffff8000000000
Signed-off-by: Andrew Mulbrook <andrew262@gmail.com>
- use {B} to substitute tcc_lih_path (instead of \b)
- expand CONFIG_TCC_CRTPREFIX in CONFIG_TCC_LIBPATHS
which fixes duplicate CONFIG_SYSROOT.
- put default CONFIG_SYSROOT ("") into tcc.h
- remove hack from commit db6fcce78f
because $(tccdir)/include is already in sysincludes
- configure: error out for unrecognized options.
- win32/build-tcc.bat: put libtcc into base dir where it will
find lib/include automatically, and build libtcc_test example.
This cleans up the mess from commit
8f98573658
and preceeding.
- make tcc -m64 work on windows
- execvp on windows returns 0 always, replace by spawnvp
- remove bizarre support for i386-win32-tcc -m64
This fixes a bug introduced in commit
8d107d9ffd
that produced wrong code because of interference between
0x10 bits VT_CONST and x86_64-gen.c:TREG_MEM
Also fully zero-pad long doubles on x86-64 to avoid random
bytes in output files which disturb file comparison.
--sysincludepaths=.. specify system include paths, colon separated"
Sets CONFIG_TCC_SYSINCLUDEPATHS
--libpaths=... specify system library paths, colon separated"
Sets CONFIG_TCC_LIBPATHS
--crtprefix=... specify location of crt?.o"
Sets CONFIG_TCC_CRTPREFIX
--elfinterp=... specify elf interpreter"
Sets CONFIG_TCC_ELFINTERP
Also the CONFIG_TCC_XXX were renamed to make them look
more consistent.
Also move the elf_interp definitions to tcc.h.
Add a --multiarch-triplet switch to configure. The switch will allow
files to be search for each default path in path/<triplet> and then
path.
Default paths handled that way:
- CONFIG_TCC_SYSINCLUDE_PATHS
- CONFIG_TCC_LIBPATH
- path to crt*.o
- path to libgcc_s.so.1
Path missing: elf interpreter path (will be handled in another commit)
This allows passing colon separated paths to
tcc_add_library_path
tcc_add_sysinclude_path
tcc_add_include_path
Also there are new configure variables
CONFIG_TCC_LIBPATH
CONFIG_TCC_SYSINCLUDE_PATHS
which define the lib/sysinclude paths all in one and can
be overridden from configure/make
For TCC_TARGET_PE semicolons (;) are used as separators
Also, \b in the path string is replaced by s->tcc_lib_path
(CONFIG_TCCDIR rsp. -B option)
This was already possible using
make NOTALLINONE=1
and is now the default.
To build as previously from one big source, use
make ONE_SOURCE=1
Cross compilers are still build from one source because using
separate objects requires separate build directories one per
platform which currently is not (yet) supported by the makefile.
We could probably use gnu-makeish target variables like
$(I386_CROSS): OUTDIR=build/i386
$(X64_CROSS): OUTDIR=build/x86-64
and so on ...
Also NEED_FLOAT_TYPES for arm-gen is removed. It was about
variables that are referenced from outside (libtcc, tccgen).
We could declare them in tcc.h (as with reg_classes) or have
them twice in arm-gen.c. I chose option 2.
Add the possibility to search headers in several subdirectories of
/usr/local/include and /usr/include. A possible use case would be for
tcc to search for headers in /usr/local/include/x86_64-linux-gnu,
/usr/local/include, /usr/include/x86_64-linux-gnu and /usr/include in
turn.
By default, tcc search libraries in /lib and /usr/local/lib while crt*.o
files are searched in /usr/lib and ld.so is searched in /lib.
Unfortunetely the path are hardcoded in source code. This patch allow
tcc to look in an other directory and also to look in extra directories.
It's then possible to make tcc search libraries in /lib/x86_64-linux-gnu
and /usr/local/lib/x86_64-linux-gnu while crt*.o files are searched in
/usr/lib/x86_64-linux-gnu and ld.so is searched in
/lib/x86_64-linux-gnu.
- Fix function assembly label mechanism introduced in commit
9b09fc376e to only accept alternative
name for function declaration.
- merge the code with the one introduced in commit
264a103610.
- Don't memorize token for asm label but directly the asm label.
Implement C99 Variable Length Arrays in tinycc:
- Support VLA with multiple level (nested vla)
- Update documentation with regards to VT_VLA
- Add a testsuite in tcctest.c
Add support for asm labels for functions, that is the ability to rename
a function at assembly level with __asm__ ("newname") appended in
function declaration.
files[0], and reloc_outpu will be needed for (upcoming in the next
patch) "compute default outfile name" refactored into libtcc function.
Also, since for symmetry and from libification point of view, it makes
some sense to also put all information about what was given as input to
compilation into TCCState, let's not only put files[0], but all
files and all libraries given explicitely by user.
One point: I've used bitfield for reloc_output & trimmed down
output_type to 8 bits so that TCCState stays the same in size, and also
access to output_type is (hopefully) is not slower.
By the way -- as of today, sizeof(TCCState) on i686-pc-linux-gnu is 2884
bytes...
* Replace the save/load_buffer_state by a dynarray approach:
- Filename and libname are added to a dynarray when first encountered
- Load repeatedly the files in the dynarray until no new undefined
symbol are encountered
* Replace snprintf by sprintf in libname_to_filename
* Use tcc_fileextension in filename_to_libname
* Introduce a tcc_strcpy_part fonction to copy only a subset of a
string
* Move new_undef_syms declaration from tcc.h to tccelf.c
gcc -o libtcc1.o -c lib/libtcc1.c -O2 -Wall
libtcc.c: At top level:
libtcc.c:1063: error: static declaration of 'tcc_add_file_internal' follows non-static declaration
tccelf.c:2915: note: previous implicit declaration of 'tcc_add_file_internal' was here
Signed-off-by: Sergei Trofimovich <st@anti-virus.by>
* search file from INPUT and GROUP commands in the library path in
addition to the current directory
* handle libraries specified by -lfoo options
* Search lib in GROUP command repeatedly
Without -Bsymbolic, a symbol/function in a *.so can be overridden
by a symbol/function in the main module.
That is the default search order, but not supported by tcc.
With -Bsymbolic, the linker tries to resolve a symbol/function in
the current module first.
The loader in tcc implements this search order.
We do not distinguish -Bsymbolic and -Bsymbolic-function
--
By by ... Detlef
This enables native unwind semantics with longjmp on
win64 by putting an entry into the .pdata section for
each compiled fuction.
Also, the function now use a fixed stack and store arguments
into X(%rsp) rather than using push.
