on 32bit long long support was sometimes broken. This fixes
code-gen for long long values in switches, disables a x86-64 specific
testcase and avoid an undefined shift amount. It comments out
a bitfield test involving long long bitfields > 32 bit; with GCC layout
they can straddle multiple words and code generation isn't prepared
for this.
when an alignment is explicitely given on the member itself,
or on its types attributes then respect it always. Was only
allowed to increase before, but GCC is allowing it.
The linux kernel has some structures that are page aligned,
i.e. 4096. Instead of enlarging the bit fields to specify this,
use the fact that alignment is always power of two, and store only
the log2 minus 1 of it. The 5 bits are enough to specify an alignment
of 1 << 30.
Another corner case:
struct foo6_1
{
char x;
short p:8;
short :0;
short :0;
short p2:8;
char y;
};
In MS layout the second anon :0 bit-field does _not_ adjust size or
alignment of the struct again. The first one does, though.
Bit-fields are layed out differently in visual C, this implements
a compatible mode. Checked against Visual C/C++ 2016.
Unfortunately the GCC implementation of MS layout (behind
-mms-bitfields) actually is different, and hence not compatible
with MS in all cases :-/
Such struct decl:
struct S { char a; int i;} __attribute__((packed));
should be accepted and cause S to be five bytes long (i.e.
the packed attribute should matter). So we can't layout
the members during parsing already. Split off the offset
and alignment calculation for this.
See testcases. We now support 64bit case constants. At the same time
also 64bit enum constants on L64 platforms (otherwise the Sym struct
isn't large enough for now). The testcase also checks for various
cases where sign/zero extension was confused.
See testcase. We must always paste tokens (at least if not
currently substing a normal argument, which is a speed optimization
only now) but at the same time must not regard a ## token
coming from argument expansion as the token-paste operator, nor
if we constructed a ## token due to pasting itself (that was already
checked by pp/01.c).
libtcc1 is the compiler support library and therefore needs
to function in a freestanding environment. In particular
it can't just use fprintf or stderr, which it was on x86-64
(but only when compiled by GCC). The tight integration between
libtcc1 and tcc itself makes it impossible to ever reach that
case so the abort() there is enough. abort() is strictly speaking
also not available in a freestanding environment, but it often is
nevertheless.
In certain very specific situations (involving switches
with asms inside dead statement expressions) we could generate
invalid code (clobbering the buffer so much that we generated
invalid instructions). Don't emit the decision table if the
switch itself is dead.
The callee saved registers (among them r12-r15) really need
saving/restoring if mentioned in asm clobbers, even if TCC
itself doesn't use them. E.g. the linux kernel relies on that
in its switch_to() implementation.
When intializing members where the initializer needs relocations
and the member is initialized multiple times we can't allow
that to lead to multiple relocations to the same place. The last
one must win.
Similar to GCC a local asm register variable enforces the use of a
specified register in asm operands (and doesn't otherwise
matter). Works only if the variable is directly mentioned as
operand. For that we now generally store a backpointer from
an SValue to a Sym when the SValue was the result of unary()
parsing a symbol identifier.
If the destination is an indirect pointer access (which ends up
as VT_LLOCAL) the intermediate pointer must be loaded as VT_PTR,
not as whatever the pointed to type is.
Some routines were using the wrong type (int) in passing addends,
truncating it. This matters when bit 31 isn't set and the high
32 bits are set: the truncation would make it unsigned where in
reality it's signed (happen e.g. on the x86-64 with it's load
address at top-2GB).
This target has _32 and _32S relocs (the latter being for signed
32 bit entities). All instruction displacements have to use
the 32S variants. Normal references like
.long s
normally would use the _32 variant. For normal executables this
doesn't matter. For shared libraries neither (which use PC-relative
relocs). But it matters for things like the kernel that are linked
to high addresses (signed ones). There the GNU linker would error
out on overflow for the _32 variant.
To keep life simple we simply switch from _32 to _32S altogether.
Strictly speaking it's still wrong, but in practice using _32 is
more often wrong than using _32S ;)
If a condition is always zero/non-zero we can omit the
then or else code. This is complicated a bit by having to
deal with labels that might make such code reachable without
us yet knowing during parsing.
Not fully thought out. You can't jump inside stmt exprs,
but you can jump out of them. So there's a difference
between undefined but declared labels at the end of stmt
exprs and those defined inside. Additionally it should
also be checked if a label defined inside a stmt expr
was tentatively created as declared from outside.
I'm not prepared doing that right now, so simply revert.
This reverts commit 9160e4cab9147d77840cc44a285031fdb4640cf9.
One can't jump into statement expressions from outside
them, like the following:
int i = ({ label: foo(); 42; });
goto label;
We reject this by making the labels simply not available
outside (GCC has a nicer error message about jumping into
a statement expression).
In statement expression we really mustn't emit backward jumps
under nocode_wanted (they will form infinte loops as no expressions
are evaluated). Do-while and explicit loop with gotos weren't
handled.
This happens when e.g. string constants (or other static data)
are passed as operands to inline asm as immediates. The produced
symbol ref wouldn't be found. So tighten the connection between
C and asm-local symbol table even more.
Our preprocessor throws away # line-comments in asm mode.
It did so also inside preprocessor directives, thereby
removing stringification. Parse defines in non-asm mode (but
retain '.' as identifier character inside macro definitions).
The return value of statement expressions might refer to local
symbols, so those can't be popped. The old error message always
was just a band-aid, and since disabling it for pointer types it
wasn't effective anyway. It also never considered that also the
vtop->sym member might have referred to such symbols (see the
testcase with the local static, that used to segfault).
For fixing this (can be seen better with valgrind and SYM_DEBUG)
simply leave local symbols of stmt exprs on the stack.
The include directive needs to be parsed as pp-tokens, not
as token (i.e. no conversion to TOK_STR or TOK_NUM). Also fix
parsing computed includes using quoted strings.
That, as well as "sym = expr", if expr contains symbols.
Slightly tricky because a definition from .set is overridable,
whereas proper definitions aren't.
This doesn't yet allow using this for override tricks from C
and global asm blocks because the symbol tables from C and asm
are separate.
But like GCC do warn about changes in signedness. The latter
leads to some changes in gen_assign_cast to not also warn about
unsigned* = int*
(where GCC warns, but only with extra warnings).
This requires correctly handling the REX prefix.
As bonus we now also support the four 8bit registers
spl,bpl,sil,dil, which are decoded as ah,ch,dh,bh in non-long-mode
(and require a REX prefix as well).
For
union U { struct {int a,b}; int c; };
union U u = {{ 1, 2, }};
The unnamed first member of union U needs to actually exist in the
structure so initializer parsing isn't confused about the double braces.
That means also the a and b members must be part of _that_, not of
union U directly. Which in turn means we need to do a bit more work
for field lookup.
See the testcase extension for more things that need to work.
Remove dead code and variables. Properly check for unions when
skipping fields in initializers. Make tests2/*.expect depend
on the .c files so they are automatically rebuilt when the latter
change.
E.g. "struct { struct S s; int a;} = { others, 42 };"
if 'others' is also a 'struct S'. Also when the value is a
compound literal. See added testcases.
Start reimplementing the whole initializer handling to be
conforming to ISO C. This patch just reimplements current
functionality to prepare for further changes, all tests pass.
This snippet is valid:
void foo(void);
... foo + 42 ...
the function designator is converted to pointer to function
implicitely. gen_op didn't do that and bailed out.
This must compile:
typedef int arrtype1[];
arrtype1 sinit19 = {1};
arrtype1 sinit20 = {2,3};
and generate two arrays of one resp. two elements. Before the fix
the determined size of the first array was encoded in the type
directly, so sinit20 couldn't be parsed anymore (because arrtype1
was thought to be only one element long).
lar can accept multiple sizes as well (wlx), like lsl. When using
autosize it's important to look at the destination operand first;
when it's a register that one determines the size, not the input
operand.
Given this code:
struct __attribute__((...)) Name {...};
TCC was eating "Name", hence generating an anonymous struct.
It also didn't apply any packed attributes to the parsed
members. Both fixed. The testcase also contains a case
that isn't yet handled by TCC (under a BROKEN #define).
A 'P' template modifier should avoid adding a '$' to literal
arguments. Also accept the numbered r8+ registers in an inline
asm clobber list (ignoring them for now).
In particular subtracting a defined symbol from current section
makes the value PC relative, and .org accepts symbolic expressions
as well, if the symbol is from the current section.
These are preprocessor cmdline arguments, but even in GCC they
aren't specified but rather left as being subject to changes.
Nobody should use them, but let's to a half-assed attempt
at accepting them.
The linux fixdep parse is very stupid and only recognizes
a target token when ':' is part of it. A space is permitted
in Makefile syntax, but it's easier to change our emitter
than all fixdep parsers out there.
This option includes a file as if '#include "file"' is the first
line of compiled files. It's processed after all -D/-U options
and is processed per input file.
gen_inline_functions uses the macro facilities of the preprocessor,
which would interact when macros would still be defined in a
different pre-processor implementation I'm working on.
So always free defines before generating inline functions, they
are all macro expanded already.
Michael Matz