There are situations when clang knows that the C1 and C2 constructors
or the D1 and D2 destructors are identical. We already optimize some
of these cases, but cannot optimize it when the GlobalValue is
weak_odr.
The problem with weak_odr is that an old TU seeing the same code will
have a C1 and a C2 comdat with the corresponding symbols. We cannot
suddenly start putting the C2 symbol in the C1 comdat as we cannot
guarantee that the linker will not pick a .o with only C1 in it.
The solution implemented by GCC is to expand the ABI to have a comdat
whose name uses a C5/D5 suffix and always has both symbols. That is
what this patch implements.
llvm-svn: 217874
Now that llvm cannot represent alias cycles, we have to diagnose erros just
before trying to close the cycle. This degrades the errors a bit. The real
solution is what it was before: if we want to provide good errors for these
cases, we have to be able to find a clang level decl given a mangled name
and produce the error from Sema.
llvm-svn: 209008
For namespaces, this is consistent with mangling and GCC's debug info
behavior. For structs, GCC uses <anonymous struct> but we prefer
consistency between all anonymous entities but don't want to confuse
them with template arguments, etc, so we'll just go with parens in all
cases.
llvm-svn: 205398
With this patch we output the in the order
C2
C1
D2
D1
D0
Which means that a destructor or constructor that call another is output after
the callee. This is a bit easier to read IHMO and a tiny bit more efficient
as we don't put a decl in DeferredDeclsToEmit.
llvm-svn: 196784
This patch disables aliasing (and rauw) of derived dtors to base dtors at -O0.
This optimization can have a negative impact on the debug quality.
This was a latent bug for some time with local classes, but got noticed when it
was generalized and broke gdb's destrprint.exp.
llvm-svn: 194618
The original decls are created when used. The replacements are created at the
end of the TU in reverse order.
This makes the original order far better for testing. This is particularly
important since the replacement logic could be used even when
-mconstructor-aliases is not used, but that would make many tests hard to read.
This is a fixed version of r194357 which handles replacing a destructor with
another which is an alias to a third one.
llvm-svn: 194452
The original decls are created when used. The replacements are created at the
end of the TU in reverse order.
This makes the original order far better for testing. This is particularly
important since the replacement logic could be used even when
-mconstructor-aliases is not used, but that would make many tests hard to read.
llvm-svn: 194357
Unlike an alias a rauw is always safe, so we don't need to avoid this
optimization when the replacement is not know to be available in every TU.
llvm-svn: 194288
This is a small optimization on linux, but should help more on windows
where msvc only outputs one destructor if there would be two identical ones.
llvm-svn: 194095
This is a small optimization on linux, but should help more on windows
where msvc only outputs one destructor if there would be two identical ones.
llvm-svn: 194046
With this patch we produce alias for cases like
template<typename T>
struct foobar {
foobar() {
}
};
template struct foobar<void>;
We just have to be careful to produce the same aliases in every TU because
of comdats.
llvm-svn: 194000
With this patch we produce alias for cases like
template<typename T>
struct foobar {
foobar() {
}
};
template struct foobar<void>;
It is safe to use aliases to weak symbols, as long and the alias itself is also
weak.
llvm-svn: 192300
I broke this in r155838 by not actually instantiating non-dependent default arg
expressions. The motivation for that change was to avoid producing duplicate
conversion warnings for such default args (we produce them once when we parse
the template - there's no need to produce them at each instantiation) but
without actually instantiating the default arg, things break in weird ways.
Technically, I think we could still get the right diagnostic experience without
the bugs if we instantiated the non-dependent args (for non-dependent params
only) immediately, rather than lazily. But I'm not sure if such a refactoring/
change would be desirable so here's the conservative fix for now.
llvm-svn: 155893
This model uses the 'landingpad' instruction, which is pinned to the top of the
landing pad. (A landing pad is defined as the destination of the unwind branch
of an invoke instruction.) All of the information needed to generate the correct
exception handling metadata during code generation is encoded into the
landingpad instruction.
The new 'resume' instruction takes the place of the llvm.eh.resume intrinsic
call. It's lowered in much the same way as the intrinsic is.
llvm-svn: 140049
hierarchy of delegation, and that EH selector values are meaningful
function-wide (good thing, too, or inlining wouldn't work).
2,3d
1a
hierarchy of delegation and that EH selector values have the same
meaning everywhere in the function instead of being meaningful only
in the context of a specific selector.
This removes the need for routing edges through EH cleanups,
since a cleanup simply always branches to its enclosing scope.
llvm-svn: 137293
aren't actually going to make a normal cleanup for. Sometimes
we optimistically create branches to such blocks for fixups,
and then we resolve the fixup to somewhere within the cleanup's
scope, and then the cleanup is actually not reachable for some
reason. The process of resolving the fixup leaves us with
switches whose default edge leads to the cleanup; we can
replace that with unreachable, then (in many cases) turn
the switch into an unconditional branch.
Fixes PR10467.
llvm-svn: 137011
- an off-by-one error in emission of irregular array limits for
InitListExprs
- use an EH partial-destruction cleanup within the normal
array-destruction cleanup
- get the branch destinations right for the empty check
Also some refactoring which unfortunately obscures these changes.
llvm-svn: 134890
- Emit default-initialization of arrays that were partially initialized
with initializer lists with a loop, rather than emitting the default
initializer N times;
- support destroying VLAs of non-trivial type, although this is not
yet exposed to users; and
- support the partial destruction of arrays initialized with
initializer lists when an initializer throws an exception.
llvm-svn: 134784
to be careful to emit landing pads that are always prepared to handle a
cleanup path. This is correct mostly because of the fix to the LLVM
inliner, r132200.
llvm-svn: 132209
self-host. Hopefully these results hold up on different platforms.
I tried to keep the GNU ObjC runtime happy, but it's hard for me to test.
Reimplement how clang generates IR for exceptions. Instead of creating new
invoke destinations which sequentially chain to the previous destination,
push a more semantic representation of *why* we need the cleanup/catch/filter
behavior, then collect that information into a single landing pad upon request.
Also reorganizes how normal cleanups (i.e. cleanups triggered by non-exceptional
control flow) are generated, since it's actually fairly closely tied in with
the former. Remove the need to track which cleanup scope a block is associated
with.
Document a lot of previously poorly-understood (by me, at least) behavior.
The new framework implements the Horrible Hack (tm), which requires every
landing pad to have a catch-all so that inlining will work. Clang no longer
requires the Horrible Hack just to make exceptions flow correctly within
a function, however. The HH is an unfortunate requirement of LLVM's EH IR.
llvm-svn: 107631
aren't dropping all exception specifications on destructors, the
exception specifications on implicitly-declared destructors were
detected as being wrong (which they were).
Introduce logic to provide a proper exception-specification for
implicitly-declared destructors. This also fixes PR6972.
Note that the other implicitly-declared special member functions also
need to get exception-specifications. I'll deal with that in a
subsequent commit.
llvm-svn: 107385
