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.
Example:
int a = 1;
void f(void)
{
int a = 2;
{
extern int a; // = 1 !!
....
To get this (more) correctly there is a new function to copy
syms between local to global stacks.
Also, this patch changes the meaning of VT_EXTERN back
to the simpler and IMO more useful notion of
DECLARED but not (yet) DEFINED.
and that for both variables and functions. That is, VT_EXTERN
in tcc doesn't have to do with the keyword 'extern' necessarily.
Also this patch does allow
int x[];
as alias for
extern int x[];
(as do gcc and msvc)
my last inline changes caused parameter names to be overwritten
always (as VT_EXTERN now doesn't mark the current def anymore),
leading to a compile error when including windows.h. Rework this.
Also silence a warning that currently happens for mingw, which is
written with gnu-inline behaviour in mind. Our work-arounds
of using "static inline" actually create invalid C (which we warn
about). Until we implement this properly, just silence the warning.
there's no need for two new flags in type.t . We just can't use
VT_EXTERN as marker if functions are defined or not (like we can
for objects), and then can simply implement the rules of C99/C11
by not overwriting VT_STATIC/VT_EXTERN at all but rather only
look at them. A function already on the inline list can be
forced by removing the VT_INLINE flag, and then linkage
follows from some combination of VT_STATIC, VT_EXTERN and VT_INLINE.
- add tests for standard conformant inline functions
- implement it
The old tinycc failed to provide a conforming implementation
of non-static inlines. It would expose external symbols where it
shouldn't and hide them where it should expose them.
This commit provides a hopefully comprehensive test suite
for how things should be done. The .expect file can be obtained
by compiling the example c file (embedded in the test)
with a conforming compiler such as gcc, clang or icc and then
printing the exported symbols (e.g., with nm+awk+sort).
(The implementation currently reserves two new VT_ flags.
If anyone can provide an implementation without reserving
two extra flags, please replace mine.)
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.
anonymous struct members were somewhat broken as the testcase
demonstrates. The reason is the jumping through hoops to fiddle
with the offsets I once introduced to avoid having to track
a cumulative offset. That's now not necessary anymore and actively
harmful, doing the obvious thing is now better.
see testcase, when the inner array dimension of multi-dimensional
VLAs isn't given TCC was generating invalid vstack accesses.
Those are actually invalid, so just diagnose them.
this test is run only on i386 so its failing went unnoticed for
a while, since 1fd3709379. IS_ASM_SYMs should not be tested
for conflicting types, the C typing overrides.
_Noreturn, just like __attribute__((noreturn)), is ignored.
I also added stdnoreturn.h, in all its glorious uselessness.
_Alignas only works for integer expressions right now. In order
to comply, we need:
- _Alignas(type) -> _Alignas(_Alignof(type)).
- stdalign.h as soon as it is done.
Note: DR 444 is supported; it works on struct members.
Signed-off-by: Devin Hussey <husseydevin@gmail.com>
see testcases. A local 'extern int i' declaration needs to
refer to the global declaration, not to a local one it might
be shadowing. Doesn't seem to happen in the wild very often as
this was broken forever.
in presence of invalid source code we can't rely on the
next token to determine if we have or haven't already parsed
an initializer element, we really have to track it in some separate
state; it's a flag, so merge it with the other two we have (size_only
and first). Also add some syntax checks for situations which
formerly lead to vstack leaks, see the added testcases.
sometimes abstract decls in parameter lists left the returned name
uninitialized potentially leading to segfaults, like in
int f(int ()) {
return 0;
}
Deal with this.
like on 'enum myenum { L = -1 } L;'. It's a bit tedious as
there are two paths (for global vs local symbols), and because
the scope and enum_val share same storage.
encode most things in Syms, do only as much work as necessary
(e.g. pending cleanups), don't track scopes in a large
structure (instead encode the scopes with cleanups directly
in the cleanups tree). Removes ca. 120 lines of code.
old implementation use only a global static array for storing
ScopeTracker which have the advantage to be fast, but you can't
use cleanup in a function that have move than SCOPE_TCK_STORE_SIZE
scopes.
I don't want to use only dynarray_* as it would slow down tcc for
every functions, so I keep both stores.
The major difficulty was to handle cleanup when a goto happen
to do so, I've had a "ScopeTracker" struct.
I can't use local_scope because that would not work with code like below
as local_scope would be at the same level:
{
char * __attribute__ ((cleanup(clean_function))) str = "hej";
goto next;
}
{
next:
}
Support multiple __label__ declarations at the beginning of a block
as long as they're contiguous.
gcc and clang accept:
{ __label__ a,b; __label__ c; /*...*/ }
.
Tcc would fail it. This patch makes it accept it.
The patch:
- if (tok == TOK_LABEL) {
+ while (tok == TOK_LABEL) {
Before this patch, save_reg can't reuse the temporary local variable
created before to save register. It may consume a lot of stack memory. this patch make save_reg reuse the temporary local variable.
when parsing the type in this cast:
(int (__attribute__(X) *)(int))foo
we ignored the attribute, which matters if it's e.g. a 'stdcall'
attribute on the function pointer. Only this particular placement
was misparsed. Putting the attribute after the '*' or outside the inner
parens worked. This idiom seems to be used on SQLite, perhaps this
fixes a compilation problem on win32 with that.
like qualifier merging the array sizes are merged as well
for the operands of ?:, and they must not statically influence
the types of decls.
Also fix some style problems, spaces aren't stinky :)
char **argv;
_Generic(argv, char**: (void)0);
_Generic(0?(char const*)0:argv[0], char const*: (void)0);
_Generic(argv, char**: (void)0);
would fail because the type of argv would get modified by the
ternary. Now allocate a separate type on the value stack to
prevent this error.
tcc would reject e.g.,
void f(){ struct {_Bool x:_Generic(({0;}),default:1);} my_x; }
with `expected constant`. This patch makes it accept it.
(The patch also makes tcc's _Generic a little more "generic" than that
of gcc and clang in that that tcc now also accepts
`struct {_Bool x:_Generic(({0;}),default:1);} my_x;` in file scope
while gcc and clang don't, but I think there's no harm in that
and gcc and clang might as well accept it in filescope too, given
that they have no problem with
e.g., `/*filescope:*/int x=1, y=2, z=_Generic(x+y, int:3);`)
grischka