See added testcase 19.c from a bug report. The problem is reading outside
the arguments buffers, even though we aren't allowed to. The single
can_read_stream variable is not enough, sometimes we need to be able
to pop into outer contexts but not into arbitrarily outside contexts.
The trick is to terminate argument tokens with a EOF (and not just with
0 that makes us pop contexts), and deal with that in the few places
we have to,
This enables some cleanups of the can_read_stream variable use.
Simple implementation, I'm not even sure to respect C standart here,
but it should work with most use case.
This add an case in unary(), and generate TokString depending of _Generic
controlling exression, use begin_macro to "push"
the generated TokString, then call unary() again before exiting the switch
so the just add token are reevaluate again.
This reverts commit d4fe9aba3f.
I was confused by the fact that string literals aren't writable.
Nevertheless the type isn't const. As extension in GCC it's const
with -Wwrite-string, which is exactly what we had before.
GCC also wonders in a comment if it's really a good idea to change
expression types based on warning flags (IMHO it's not), but let's
be compatible. So restore the state from before.
Don't make the standard mandated types of string literals
depends on warning options. Instead make them always const,
but limit the emission of the warning by that option.
any dyn symbols. The if( !s1->static_link ) prevents tcc from
crashing when buiding a program linked to dietlibc.
The section header should not contain the number of local symbols when
the sh_size is null. This makes the header compliant and IDA will not
issue any warnings when an executable is disassembled.
Only warn if the struct has a non-zero size. You can't create objects
of zero-sized structs, but they can be used inside sizeof (e.g.
"sizeof (struct {int :0;})". The warning would always trigger for these,
but as no objects can be created no accesses can ever happen.
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.
- 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
For integer promotion with for example arithmetics or
expr_cond (x ? y : z), integral types need to be promoted
to signed if they fit.
According to latest standards, this also applies to bit-field
types taking into account their specific width.
In tcc, VT_BITFIELD set means width < original type width
Field-widths between 33 and 63 are promoted to signed long long
accordingly.
struct { unsigned long long ullb:35; } s = { 1 };
#define X (s.ullb - 2)
int main (void)
{
long long Y = X;
printf("%d %016llx %016llx\n", X < 0, -X, -Y);
return 0;
}
Results:
GCC 4.7 : 0 0000000000000001 FFFFFFF800000001
MSVC : 1 0000000000000001 0000000000000001
TCC : 1 0000000000000001 0000000000000001
Also, gcc would promote long long bitfields of size < 32
to int as well. Example:
struct { unsigned long long x:20; } t = { 123 };
/* with gcc: */ printf("%d %d\n", t.x, 456);
/* with tcc: */ printf("%lld %d\n", t.x, 456);
bit_pos + bit_size > type_size * 8
must NEVER happen because the code generator can read/write
only the basic integral types.
Warn if tcc has to break GCC compatibility for that reason
and if -Wgcc-compat is given.
Example:
struct __attribute__((packed)) _s
{
unsigned int x : 12;
unsigned char y : 7;
unsigned int z : 28;
};
Expected (GCC) layout (sizeof struct = 6)
.xxxxxxxx.xxxxyyyy.yyyzzzzz.zzzzzzzz.zzzzzzzz.zzzzzzz0.
But we cannot read/write 'char y'from 2 bytes in memory.
So we have to adjust:
.xxxxxxxx.xxxx0000.yyyyyyyz.zzzzzzzz.zzzzzzzz.zzzzzzzz.zzz00000
Now 'int z' cannot be accessed from 5 bytes. So we arrive
at this (sizeof struct = 7):
.xxxxxxxx.xxxx0000.yyyyyyy0.zzzzzzzz.zzzzzzzz.zzzzzzzz.zzzz0000
Otherwise the bitfield load/store generator needs to be
changed to allow byte-wise accesses.
Also we may touch memory past the struct in some cases
currently. The patch adds a warning for that too.
0: 55 push %ebp
1: 89 e5 mov %esp,%ebp
3: 81 ec 04 00 00 00 sub $0x4,%esp
9: 90 nop
struct __attribute__((packed)) { unsigned x : 5; } b = {0} ;
a: 8b 45 ff mov -0x1(%ebp),%eax
d: 83 e0 e0 and $0xffffffe0,%eax
10: 89 45 ff mov %eax,-0x1(%ebp)
This touches -0x1 ... +0x3(%ebp), hence 3 bytes beyond
stack space. Since the data is not changed, nothing
else happens here.
"s"[i<2] and "s" + (i<2) are literally identical, but the latter triggers
a warning from clang because it looks so much like a noob is trying to
concatenate an integer and a string. The former is arguably more clear.
Do not enable musl or uclibc native support if a GNU linker is
already present. This avoids interference for example on a
Debian platform with musl-dev installed. More work is required
to select musl libc in that case, with additional configure flags.
Mark TCCState parameter as unused in tcc_undefine_symbol(), tcc_add_symbol(),
tcc_print_stats(), asm_get_local_label_name(), use_section1(), tccpp_delete(),
tcc_tool_ar(), tcc_tool_impdef(), and tcc_tool_cross().
Also mark it unused in tcc_add_bcheck() unless CONFIG_TCC_BCHECK.
Remove it entirely in ld_next().
"missing intitializer for field op_type" with gcc -Wextra. It's
zero-initialized anyway, and not that much a hassle to explicitely
initialize either, so let's be nice and make it not warn.
* tccgen: re-allow long double constants for x87 cross
sizeof (long double) may be 12 or 16 depending on host platform
(i386/x86_64 on unix/windows).
Except that it's 8 if the host is on windows and not gcc
was used to compile tcc.
* win64: fix builtin_va_start after VT_REF removal
See also a8b83ce43a
* tcctest.c: remove outdated limitation for ll-bitfield test
It always worked, there is no reason why it should not work
in future.
* libtcc1.c: exclude long double conversion on ARM
* Makefile: remove CFLAGS from link recipes
* lib/Makefile: use target DEFINES as passed from main Makefile
* lib/armflush.c lib/va_list.c: factor out from libtcc1.c
* arm-gen.c: disable "depreciated" warnings for now
'extern int i = 42;' at file scope (but not in function scope!) is
allowed and is a proper definition, even though questionable style;
some compilers warn about this.
local symbols can be resolved statically, they don't have to be
done dynamically, so this is a slight speedup at load time for
produced executables and shared libs. The musl libc also rejects
any STB_LOCAL symbols for dynamic symbol resolution, so there it
also fixes use of shared libs created by tcc.
some newer systems have debug sections compressed by default, which
includes those in the crt[1in].o startup files. These can't simply
be concatenated like all others (which leads to invalid section contents
ultimately making gdb fail) but need special handling.
Instead of that special handling (decompressing, which in turn requires
linking against zlib) let's just ignore such sections, even though that
means to also ignore all other debug sections from that particular input
file. Our own generated files of course don't have the problem.
See the added testcase. When one used designators like .a.x to initialize
sub-members of members, and didn't then initialize all of them the
required zero-initialization of the other sub-members wasn't done.
The fix also enables tiny code cleanups.
See testcase. If an enum has only positive values, fits N bits,
and is placed in a N-bit bit-field that bit-fields must be treated
as unsigned, not signed.
This invalid function definition:
int f()[] {}
was tried to be handled but there was no testcase if it actually worked.
This fixes it and adds a TCC only testcase.
ONE_SOURCE=yes cross-compilers currently only depend on tcc.c, which
itself has no further deps. So e.g. changing tccgen.c or tcctok.h
don't automatically rebuild cross compilers. Let's go over
the intermediate $(X)tcc.o file which automatically depends on
LIBTCC_INC, which are all relevant source files.
introduce common_section (SHN_COMMON), factorize some handling
in decl_initializer_alloc, add section_add and use it to factorize
some code that allocates stuff in sections (at the same time also fixing
harmless bugs re section alignment), use init_putv to emit float consts
into .data from gv() (fixing an XXX).
factor code a bit for transforming tokens into SValues. This revealed
a bug in TOK_GET (see testcase), which happened to be harmless before.
So fix that as well.
