Commit Graph

150 Commits

Author SHA1 Message Date
herman ten brugge
3b617fdc53 Add sigsetjmp/siglongjmp bound checking support
tcctok.h:
- Add sigsetjmp/__sigsetjmp/siglongjmp

tccgen.c:
- redirect sigsetjmp/siglongjmp to bcheck.c code

i386-gen.c/x86_64-gen.c
- gcall_or_jmp: Set func_bound_add_epilog also when sigsetjmp is called
- gen_bounds_epilog: Only call __bound_local_new when needed (unrelated)

bcheck.c:
- Add __bound_siglongjmp
- __bound_setjmp/__bound_long_jump: Check no_checking
- Optimize __bound_local_delete (unrelated)

Modify testcase:
- 114_bound_signal
2020-05-25 12:26:55 +02:00
herman ten brugge
045632defb Fix gcc10 warnings
i386-gen.c:
- load/gen_opf: set v1.sym to NULL

lib/Makefile:
- Add -gstabs -fno-omit-frame-pointer -Wno-unused-function -Wno-unused-variable

lib/bt-log.c:
- tcc_backtrace: Prevent __builtin_frame_address warning

tccgen.c:
- struct_layout: Set t.t to VT_BYTE
- default_debug: Use octal instead of -1 to make size_t work

tccpp.c:
- tal_realloc_impl: Only memcpy when p set

x86_64-gen.c:
- gen_bounds_epilog: Do not save/restore rcx (not caller/callee saved)
                     This also made stack not aligned to 16 bytes.
2020-05-23 20:27:43 +02:00
herman ten brugge
b5b92c7d6d Add setjmp/longjmp bound checking support
tcctok.h:
- Add __bound_setjmp/setjmp/_setjmp/longjmp

tccgen.c:
- redirect setjmp/longjmp to bcheck.c code

i386-gen.c/x86_64-gen.c
- Change func_bound_alloca_used into func_bound_add_epilog
- Set func_bound_add_epilog also when setjmp is called

bcheck.c:
- Add __bound_setjmp/__bound_longjmp
- __bound_local_delete: remove setjmp if used in function
- __bound_exit: clear setjmp list and print statistic
- make malloc_redir more readable (unrelated)

New testcases:
- 115_bound_setjmp
- 116_bound_setjmp2
2020-05-23 20:02:41 +02:00
grischka
9c28349757 tccgen.c: cleanup debug support
from 3e731e3a78

tccgen.c:
- make 'struct default_debug' const
- pass TCCState* as parameter to tcc_debug_xxx functions
- always check tcc_state->do_debug before calling functions
- factor out tcc_debug_extern_sym()
- remove formats "%lld"/"%llu" (not reliable on windows)

xxx-gen files:
- set func_vt/var from caller
2020-05-11 11:41:56 +02:00
grischka
5bc1720776 tccgen.c: move 'alloca_used' complication to *-gen files
related to commit 8370bc03a1
2020-05-11 11:41:56 +02:00
herman ten brugge
8370bc03a1 Allow signal handlers when bound checking
Disable generating bound_local_new/bound_local_delete when not needed.
Add new testcase 114_bound_signal.
2020-05-05 08:31:57 +02:00
Michael Matz
245f6a0d13 stdarg: always have the __builtin_va_* available
This makes available the __builtin_va_list type and __builtin variants
of va_start, va_arg, va_copy and va_end.  We do this via a header file
that's prepended to all compilations always (except if merely
preprocessing): tcc_predefs.h.  That header could also be used
for predefining other builtins in the future.

We don't need the define hacks for musl anymore with this.

Also fix x86_64 gfunc_prologue to reserve enoug space for the
full va_list structure, not just 16 bytes.
2020-04-15 22:06:52 +02:00
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
Michael Matz
65f2fe390c Cleanup new bound checking code
remove quadratic loops by not using side tables; address-taken
can simply be a flag per local sym, and the lbounds section can
be filled after symbols go out of scope at which point we know
if the address was taken, so that there's no need to compress it
again after the funcion is done.
2020-01-16 01:19:59 +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
Michael Matz
c8ca64d28b Adjust return value promotion for some archs
this is a bit complicated: for i386 and x86-64 we really need to
extend return values ourself, as the common code now does.  For arm64
this at least preserves old behaviour.  For riscv64 we don't have to
extend ourself but can expect things to be extended up to int (this
matters for var-args tests, when the sign-extension to int64 needs to
happen explicitely).  As the extensions are useless, don't do them.

And for arm32 we actually can't express GCC behaviour: the callee side
expects the return value to be correctly extended to int32, but
remembers the original type.  In case the ultimate target type for the
call result is only int, no further extension is done.  But in case
the target type is e.g. int64 an extension happens, but not from int32
but from the original type.  We don't know the ultimate target type,
so we have to choose a type to put into vtop:
* original type (plus VT_MUSTCAST) - this looses when the ultimate
  target is int (GCC: no cast, TCC: a cast)
* int (without MUSTCAST) - this looses when the ultimate target is
  int64 (GCC: cast from original type, TCC: cast from int)
This difference can only be seen with undefined sources, like the
testcases, so it doesn't seem worthwhile to try an make it work, just
disable the test on arm and choose the second variant as that generates
less code.
2019-12-17 01:46:06 +01:00
grischka
a64353ce71 tccgen.c: generic char/short promotion for function return values 2019-12-16 21:58:32 +01:00
grischka
89372dc482 update gen_cast 2019-12-16 21:37:44 +01:00
grischka
35475b5423 remove VT_LVAL_BYTE etc.
For some reason there was no point for that anymore.
2019-12-16 20:59:23 +01:00
grischka
5914f4d57d tccgen.c: cleanup reg classes
wrap some copy&paste code into functions
2019-12-16 20:44:48 +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
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
426d32af23 Fix alloca on x86_64 windows 2019-12-11 14:06:15 +01:00
herman ten brugge
a0bc149b0c Fix bounds checking after concurrently commit 2019-12-11 12:07:48 +01:00
grischka
72729d8e36 allow libtcc states to be used concurrently
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.
2019-12-11 02:36:19 +01:00
herman ten brugge
4461f38a9e Fix bounds checking for linux/windows 2019-12-10 08:07:25 +01:00
herman ten brugge
fadfc118e5 Fix sse calling bug 2019-10-29 07:19:42 +01:00
grischka
ce1ef5b8fc some smaller fixes
- libtcc.c/tccpp.c: fix -U option for multiple input files
- libtcc: remove decl of tcc_add_crt() for PE
- tcc.h: define __i386__ and __x86_64__ for msvc
- tcc.h: undef __attribute__ for __TINYC__ on gnu/linux platforms
- tccelf.c: disable prepare_dynamic_rel unless x86/x64
- tccpe.c: construct rather than predefine PE section flags
- tccpp.c: (alt.) fix access of dead stack variable after error/longjmp
- x86_64-gen.c: fix func_alloca chain for nocode_wanted
- tccpp.c/tccgen.c: improve file:line info for inline functions
- winapi/winnt.h: correct position for DECLSPEC_ALIGN attribute
- win32/lib/crt: simplify top exception handler (needed for signal)
- arm64-gen.c: remove dprintf left from VT_CMP commit
- tccgen.c: limit binary scan with gcase to > 8 (= smaller code)
- tccgen.c: call save_regs(4) in gen_opl for cmp-ops (see test in tcctest.c)
2019-07-14 22:46:19 +02:00
grischka
8227db3a23 jump optimizations
This unifies VT_CMP with VT_JMP(i) by using mostly VT_CMP
with both a positive and a negative jump target list.

Such we can delay putting the non-inverted or inverted jump
until we can see which one is nore suitable (in most cases).

example:
    if (a && b || c && d)
        e = 0;

before this patch:
   a:	8b 45 fc             	mov    0xfffffffc(%ebp),%eax
   d:	83 f8 00             	cmp    $0x0,%eax
  10:	0f 84 11 00 00 00    	je     27 <main+0x27>
  16:	8b 45 f8             	mov    0xfffffff8(%ebp),%eax
  19:	83 f8 00             	cmp    $0x0,%eax
  1c:	0f 84 05 00 00 00    	je     27 <main+0x27>
  22:	e9 22 00 00 00       	jmp    49 <main+0x49>
  27:	8b 45 f4             	mov    0xfffffff4(%ebp),%eax
  2a:	83 f8 00             	cmp    $0x0,%eax
  2d:	0f 84 11 00 00 00    	je     44 <main+0x44>
  33:	8b 45 f0             	mov    0xfffffff0(%ebp),%eax
  36:	83 f8 00             	cmp    $0x0,%eax
  39:	0f 84 05 00 00 00    	je     44 <main+0x44>
  3f:	e9 05 00 00 00       	jmp    49 <main+0x49>
  44:	e9 08 00 00 00       	jmp    51 <main+0x51>
  49:	b8 00 00 00 00       	mov    $0x0,%eax
  4e:	89 45 ec             	mov    %eax,0xffffffec(%ebp)
  51:   ...

with this patch:
   a:	8b 45 fc             	mov    0xfffffffc(%ebp),%eax
   d:	83 f8 00             	cmp    $0x0,%eax
  10:	0f 84 0c 00 00 00    	je     22 <main+0x22>
  16:	8b 45 f8             	mov    0xfffffff8(%ebp),%eax
  19:	83 f8 00             	cmp    $0x0,%eax
  1c:	0f 85 18 00 00 00    	jne    3a <main+0x3a>
  22:	8b 45 f4             	mov    0xfffffff4(%ebp),%eax
  25:	83 f8 00             	cmp    $0x0,%eax
  28:	0f 84 14 00 00 00    	je     42 <main+0x42>
  2e:	8b 45 f0             	mov    0xfffffff0(%ebp),%eax
  31:	83 f8 00             	cmp    $0x0,%eax
  34:	0f 84 08 00 00 00    	je     42 <main+0x42>
  3a:	b8 00 00 00 00       	mov    $0x0,%eax
  3f:	89 45 ec             	mov    %eax,0xffffffec(%ebp)
  42:   ...
2019-06-24 11:40:01 +02:00
grischka
1b57560502 nocode, noreturn
A more automatic approach to code suppression (aka. nocode_wanted)

The simple rules are:
- Clear 'nocode_wanted' at (im/explicit) label IF it was used
- Set 'nocode_wanted' after unconditional jumps

Also in order to test this then I did add the "function might
return no value" warning, and then to make that work again I
did add the __attribute__((noreturn)).

Also moved the look ahead label check into the type parser
to gain a little speed.
2019-06-24 11:40:01 +02:00
Pascal Cuoq
944fe7036c x86-64 codegen: avoid allocating VLA of size 0 2019-06-19 20:43:10 +02:00
Michael Matz
c07e81b087 Tidy some code
the real difference is in decl0 where we can use external_sym
just fine also for function definitions, we don't have to use
external_global_sym.  Setting VT_EXTERN in external_sym isn't
necessary either (the type will have it set if necessary).
The rest is tidying: removing unused arguments and moving
some code around.
2019-04-18 03:42:23 +02:00
Michael Matz
749d19d70b Fix sub-int returns on x86-64 and i386
the ABIs (and other compilers) extend sub-int return values in the
caller.  TCC extends them in the callee.  For compatibility with
those other compilers we have extend them in the caller as well.
That introduces a useless double extension in pure TCC-compiled code,
but fixing that generally requires that the code generator of TCC would
understand sub-int types.  For the time being bite the bullet.
2019-02-10 18:27:41 +01:00
Michael Matz
45b8b0e57d Revert 337dc84b (other -static fix)
this should work now with 05f6aa1a.
2019-01-13 06:01:59 +01:00
Michael Matz
adbe794a46 Properly access sym_attrs
in corner cases the direct access to the sym_attrs[] array in the
backends is out of bounds and replacec garbage symindices into
the relocs.
2019-01-13 02:55:44 +01:00
Kurt Nalty
337dc84b57 Fixed -static linking on x86_64 Linux 2019-01-11 02:32:48 +08:00
Pursuer
3f05d88d5b optimize the generated code when save_reg is required (2)
In gfunc_call, regisger will be saved before gcall_or_jmp. The register
stored the function will be saved too, though in some generator the SValue
of this function will be immediately poped after gcall_or_jmp, and no need to be saved. So I modify some generator to avoid save redundant SValue before gcall_or_jmp.
2019-01-11 02:32:12 +08:00
Michael Matz
d79caa9ff6 x86-64: Fix calls via absolute function pointers
linkers don't treat relocations using symindex 0 (undefined)
very well, it can't be misused as indicator for an absolute number.
Just don't bother with special casing this, rather emit an indirect
call/jump right away. ARM64 needs the same (and didn't handle
calls via constant absolute func pointers before).

The testcase as is doesn't fail without the patch, it actually
needs separate compilation (to -fPIC .o file, then to shared lib)
to fail.
2018-07-02 01:57:29 +02:00
Michael Matz
65c7f19deb Fix stored type of arguments on x86-64
the lvalue Syms for arguments didn't correctly reflect
their own types in all cases (a side-effect of the type being
stored in type->t and the ->r members (as VT_LVAL_xxx), so the below
used an int load (not a byte load) in the conditional.

extern void bar (void);
void foo (signed char c)
{
  signed char x = c;
  if (c)
    bar();
}
2018-06-24 20:12:51 +02:00
grischka
8f6fcb709a misc fixes
misc fixes including:
- tcc.c: fix "tcc -vv" for libtcc1.a on win32/PE
- tccelf.c: fix a crash when GOT has no relocs (witn -nostdlib)
- tccelf.c: fix stab linkage for zero n_strx
- tccgen.c: fix stdcall decoration for array parameters
    int __stdcall func(char buf[10]) is _func@4 (was _func@12)
- tccgen.c: fix static variables with nocode/nodata_wanted
    see tests2/96_nodata_wanted.c
- tccrun.c: align sections using sh_addralign (for reliable function_alignment)
- tests2/Makefile sort 100 after 99
- win32/include/sys/stat.h fix _stat and _wstat
- x86_64-gen.c: win64/gfunc_call: fix a bug with xmmN register args
    previously overwrote valid other xmmN registers eventually
2018-06-01 12:52:01 +02:00
Michael Matz
671dcace82 Implement function alignment via attributes
which requires being able to emit an arbitrary number of NOP
instructions, which is also implemented here.  For x86 we
could emit other sequences but these are the easiest.
2018-04-06 23:02:42 +02:00
grischka
d348a9a51d final update for 0.9.27
tccgen.c:
- fix ldouble asm hack
- fix a VLA problem on Win64 (also x86_64-gen.c)
- patch_type(): make sure that no symbol ever changes
  from global to static

tcc.c:
- tcc -vv: print libtcc1.a path also on win32

tccpe.c, tcctools.c:
- use unix LF mode to for .def output files (that is for
  creating reproducible output trees)

Makefile:
- suppress some warnings when makeinfo is missing
- call 'which install' only on win32

tests/Makefile:
- change PATH only on WINNT systems (i.e. not if cross-compiling
  on linux for win32)
- asm-c-connect.test: slim output and do diff

tccrun.c tccpe.c *-link.c:
- integrate former 'pe_relocate_rva()' into normal relocation
  This also fixes linkage of the unwind data on WIN64 for -run
  (reported by Janus Lynggaard Thorborg)

tccasm.c, tests/tcctest.c:
- fix dot (sym_index of -1 crashed in put_elf_reloc)
- massage .set a bit (see test)

other:
- #define SECTION_ABS removed
- ST_DATA Section *strtab_section: removed
- put_extern_sym2(): take int section number

Conflicts:
	tccelf.c
	tccpe.c

Conflicts:
	tccelf.c
2017-12-12 17:57:20 +01:00
Michael Matz
348dd9f4a6 Fix absolute memory references
This properly fixes what 870271ea tried to fix.  Absolute memory
references can't use %rip relative addressing, and additionally,
if the address doesn't fit 32bit (signed) it must be loaded via
movabs.  No good testcase added, it would require catching signals
and still be unreliable.
2017-11-15 13:39:28 +01:00
Michael Matz
74463eb954 Revert "gen_addrpc32: absolute ptr needs *ABS* relocation"
This reverts commit 870271ea07.

The commit is broken, you can't unconditionally emit a PC-relative
relocation without a symbol.  And if there's a symbol the addend
need to be in the relocation, not the section.
2017-11-14 16:43:22 +01:00
Larry Doolittle
1b6806e5bb Spelling fixes
Comments only, no change to functionality
2017-09-24 18:03:26 -07:00
Zdenek Pavlas
870271ea07 gen_addrpc32: absolute ptr needs *ABS* relocation
Dereferencing of absolute pointers is broken on x86_64, eg:

*(int*)NULL does not segfault but returns -4 instead
*(char*)(-10L << 20) does not return 0x55 (vsyscall page, push rbp)
2017-09-11 06:36:16 -07:00
grischka
f87afa72e0 refactor enums
Eliminate VT_ENUM as a basic type.  Instead use the integral
types VT_InT/VT_LLONG with an additional flag to indicate
that it is an enum.
2017-07-09 12:38:25 +02:00
grischka
9ba76ac834 refactor sym & attributes
tcc.h:
* cleanup struct 'Sym'
* include some 'Attributes' into 'Sym'
* in turn get rid of VT_IM/EXPORT, VT_WEAK
* re-number VT_XXX flags
* replace some 'long' function args by 'int'

tccgen.c:
* refactor parse_btype()
2017-07-09 12:34:11 +02:00
grischka
9f79b62ec4 unsorted adjustments
- configure
  * use aarch64 instead of arm64

- Makefile
  * rename the custom include file to "config-extra.mak"
  * Also avoid "rm -r /*" if $(tccdir) is empty

- pp/Makefile
  * fix .expect generation with gcc

- tcc.h
  * cleanup #defines for _MSC_VER

- tccgen.c:
  * fix const-propagation for &,|
  * fix anonymous named struct (ms-extension) and enable
    -fms-extension by default

- i386-gen.c
  * clear VT_DEFSIGN

- x86_64-gen.c/win64:
  * fix passing structs in registers
  * fix alloca (need to keep "func_scratch" below each alloca area on stack)
    (This allows to compile a working gnu-make on win64)

- tccpp.c
  * alternative approach to 37999a4fbf
    This is to avoid some slowdown with ## token pasting.
  * get_tok_str() : return <eof> for TOK_EOF
  * -funsigned-char: apply to "string" literals as well

- tccpe/tools.c: -impdef: support both 32 and 64 bit dlls anyway
2017-07-09 12:07:40 +02:00
Michael Matz
7cd1ae7710 x86-64: Fix psABI stdarg prologue
If there were more than 6 integer arguments before the ellipsis, or
there were used more than 8 slots used until the ellipsis (e.g. by
a large intermediate struct) we generated wrong code.  See testcase.
2017-05-27 22:42:18 +02:00
Michael Matz
53c5fc2246 x86-64: Rewrite linux parameter passing
This fixes two ABI testcases involving large arguments when there
are still registers available for later args.
2017-05-27 21:23:13 +02:00
grischka
28435ec58c configure: --config-musl/-uClibc switch & misc cleanups
- configure:
  - add --config-uClibc,-musl switch and suggest to use
    it if uClibc/musl is detected
  - make warning options magic clang compatible
  - simplify (use $confvars instead of individual options)
- Revert "Remove some unused-parameter lint"
  7443db0d5f
  rather use -Wno-unused-parameter (or just not -Wextra)
- #ifdef functions that are unused on some targets
- tccgen.c: use PTR_SIZE==8 instead of (X86_64 || ARM64)
- tccpe.c: fix some warnings
- integrate dummy arm-asm better
2017-05-13 08:59:06 +02:00
Larry Doolittle
19d8b8a173 Spelling fixes in C comments only 2017-05-07 21:38:09 -07:00
Michael Matz
a8b83ce43a Remove VT_REF
The canonical way to describe a local variable that actually holds
the address of an lvalue is VT_LLOCAL.  Remove the last user of VT_REF,
and handling of it, thereby freeing a flag for SValue.r.
2017-05-02 03:07:36 +02:00