The HandlerMap describes, to the runtime, what sort of catches surround
the try. In principle, this structure has to be emitted by the backend
because only it knows the layout of the stack (the runtime needs to know
where on the stack the destination of a copy lives, etc.) but there is
some C++ specific information that the backend can't reason about.
Stick this information in special LLVM globals with the relevant
"const", "volatile", "reference" info mangled into the name.
llvm-svn: 232538
Previously, we would error out on this code because the default argument
wasn't parsed until the end of Outer:
struct __declspec(dllexport) Outer {
struct __declspec(dllexport) Inner {
Inner(void *p = 0);
};
};
Now we do the checking on the closing brace of Outer instead of Inner.
llvm-svn: 232519
Add a frontend test for PR22929, which was fixed by LLVM r232449.
Besides the crash test, check that the `!dbg` attachment is sane since
its presence was the trigger.
llvm-svn: 232450
Qualifiers are located next to the TypeDescriptor in order to properly
ensure that a pointer type can only be caught by a more qualified catch
handler. This means that a catch handler of type 'const int *' requires
an RTTI object for 'int *'. We got this correct for 'throw' but not for
'catch'.
N.B. We don't currently have the means to store the qualifiers because
LLVM's EH strategy is tailored to the Itanium scheme. The Itanium ABI
stores qualifiers inside the type descriptor in such a way that the
manner of qualification is stored in addition to the pointee type's
descriptor. Perhaps the best way of modeling this for the MS ABI is
using an aggregate type to bundle the qualifiers with the descriptor?
This is tricky because we want to make it clear to the optimization
passes which catch handlers invalidate other handlers.
My current thoughts on a design for this is along the lines of:
{ { TypeDescriptor* TD, i32 QualifierFlags }, i32 MiscFlags }
The idea is that the inner most aggregate is all that is needed to
communicate that one catch handler might supercede another. The
'MiscFlags' field would be used to hold the bitpattern for the notion
that the 'catch' handler does not need to invoke a copy-constructor
because we are catching by reference.
llvm-svn: 232318
It is possible to construct an initializer for a bitfield which is not
constant. Instead of emitting code to initialize the field before the
execution of main, clang would crash.
llvm-svn: 232285
Virtual member pointers are implemented using a thunk. We assumed that
the calling convention for this thunk was always __thiscall for 32-bit
targets and __cdecl for 64-bit targets. However, this is not the case.
Mangle in whichever calling convention is appropriate for this member
function thunk.
llvm-svn: 232254
This scheme checks that pointer and lvalue casts are made to an object of
the correct dynamic type; that is, the dynamic type of the object must be
a derived class of the pointee type of the cast. The checks are currently
only introduced where the class being casted to is a polymorphic class.
Differential Revision: http://reviews.llvm.org/D8312
llvm-svn: 232241
The MS ABI utilizes a compiler generated function called the "vector
constructor iterator" to construct arrays of objects with
non-trivial constructors/destructors. For this to work, the constructor
must follow a specific calling convention. A thunk must be created if
the default constructor has default arguments, is variadic or is
otherwise incompatible. This thunk is called the default constructor
closure.
N.B. Default constructor closures are only generated if the default
constructor is exported because clang itself does not utilize vector
constructor iterators. Failing to export the default constructor
closure will result in link/load failure if a translation unit compiled
with MSVC is on the import side.
Differential Revision: http://reviews.llvm.org/D8331
llvm-svn: 232229
std::make_exception_ptr calls std::__GetExceptionInfo in order to figure
out how to properly copy the exception object.
Differential Revision: http://reviews.llvm.org/D8280
llvm-svn: 232188
A nullptr exception object can be caught by any pointer type catch
handler. However, it is not possible to express this in the exception
info for the MS ABI. As a middle ground, allow such exception objects
to be caught with pointer-to-void catch handlers.
llvm-svn: 232069
This adds support for copy-constructor closures. These are generated
when the C++ runtime has to call a copy-constructor with a particular
calling convention or with default arguments substituted in to the call.
Because the runtime has no mechanism to call the function with a
different calling convention or know-how to evaluate the default
arguments at run-time, we create a thunk which will do all the
appropriate work and package it in a way the runtime can use.
Differential Revision: http://reviews.llvm.org/D8225
llvm-svn: 231952
Using declarations which are aliases to struct types have their name
used as the struct type's name for linkage purposes. Otherwise, make
sure to give an anonymous struct defined inside a using declaration a
mangling number to disambiguate it from other anonymous structs in the
same context.
This fixes PR22809.
llvm-svn: 231909
Because the catchable type has a reference to its name, mangle the
location to ensure that two catchable types with different locations are
distinct.
llvm-svn: 231819
This is a recommit of r231150, reverted in r231409. Turns out
that -fsanitize=shift-base check implementation only works if the
shift exponent is valid, otherwise it contains undefined behavior
itself.
Make sure we check that exponent is valid before we proceed to
check the base. Make sure that we actually report invalid values
of base or exponent if -fsanitize=shift-base or
-fsanitize=shift-exponent is specified, respectively.
llvm-svn: 231711
I disabled putting the new global into the same COMDAT as the function for now.
There's a fundamental problem when we inline references to the global but still
have the global in a COMDAT linked to the inlined function. Since this is only
an optimization there may be other versions of the COMDAT around that are
missing the new global and hell breaks loose at link time.
I hope the chromium build doesn't break this time :)
llvm-svn: 231564
This broke the Chromium build. Links were failing with messages like:
obj/dbus/libdbus_test_support.a(obj/dbus/dbus_test_support.mock_object_proxy.o):../../dbus/mock_object_proxy.cc:function dbus::MockObjectProxy::Detach(): warning: relocation refers to discarded section
/usr/local/google/work/chromium/src/third_party/binutils/Linux_x64/Release/bin/ld.gold: error: treating warnings as errors
llvm-svn: 231541
Instead of creating a copy on the stack just stash them in a private
constant global. This saves both the copying overhead and the stack
space, and gives the optimizer more room to constant fold.
This tries to make array temporaries more similar to regular arrays,
they can't use the same logic because a temporary has no VarDecl to be
bound to so we roll our own version here.
The original use case for this optimization was code like
for (int i : {1, 2, 3, 4, 5, 6, 7, 8, 10})
foo(i);
where without this patch (assuming that the loop is not unrolled) we
would alloca an array on the stack, copy the 10 values over and
iterate on that. With this patch we put the array in .text use it
directly. Apart from that case this helps on virtually any passing of
a constant std::initializer_list as a function argument.
Differential Revision: http://reviews.llvm.org/D8034
llvm-svn: 231508
Find all unambiguous public classes of the exception object's class type
and reference all of their copy constructors. Yes, this is not
conforming but it is necessary in order to implement their ABI. This is
because the copy constructor is actually referenced by the metadata
describing which catch handlers are eligible to handle the exception
object.
N.B. This doesn't yet handle the copy constructor closure case yet,
that work is ongoing.
Differential Revision: http://reviews.llvm.org/D8101
llvm-svn: 231499
arithmetic type to a vector so that the arithmatic type
matches the vector element type. Without which it crashes
in Code Gen. rdar://20000762
llvm-svn: 231419
It's not that easy. If we're only checking -fsanitize=shift-base we
still need to verify that exponent has sane value, otherwise
UBSan-inserted checks for base will contain undefined behavior
themselves.
llvm-svn: 231409
Throwing a C++ exception, under the MS ABI, is implemented using three
components:
- ThrowInfo structure which contains information like CV qualifiers,
what destructor to call and a pointer to the CatchableTypeArray.
- In a significant departure from the Itanium ABI, copying by-value
occurs in the runtime and not at the catch site. This means we need
to enumerate all possible types that this exception could be caught as
and encode the necessary information to convert from the exception
object's type to the catch handler's type. This includes complicated
derived to base conversions and the execution of copy-constructors.
N.B. This implementation doesn't support the execution of a
copy-constructor from within the runtime for now. Adding support for
that functionality is quite difficult due to things like default
argument expressions which may evaluate arbitrary code hiding in the
copy-constructor's parameters.
Differential Revision: http://reviews.llvm.org/D8066
llvm-svn: 231328
-fsanitize=shift is now a group that includes both these checks, so
exisiting users should not be affected.
This change introduces two new UBSan kinds that sanitize only left-hand
side and right-hand side of shift operation. In practice, invalid
exponent value (negative or too large) tends to cause more portability
problems, including inconsistencies between different compilers, crashes
and inadequeate results on non-x86 architectures etc. That is,
-fsanitize=shift-exponent failures should generally be addressed first.
As a bonus, this change simplifies CodeGen implementation for emitting left
shift (separate checks for base and exponent are now merged by the
existing generic logic in EmitCheck()), and LLVM IR for these checks
(the number of basic blocks is reduced).
llvm-svn: 231150
isSingleElementStruct was a bit too tight in its definition of struct
so we got a mismatch between classify() and the actual code generation.
To make matters worse the code in GetByteVectorType still defaulted to
<2 x double> if it encountered a type it didn't know, making this a
silent miscompilation (PR22753).
Completely remove the "preferred type" stuff from GetByteVectorType and
make it fail an assertion if someone tries to use it with a type not
suitable for a vector register.
llvm-svn: 230971
dynamic classes in the translation unit and check whether each one's key
function is defined when we got to the end of the TU (and when we got to the
end of each module). This is really terrible for modules performance, since it
causes unnecessary deserialization of every dynamic class in every compilation.
We now use a much simpler (and, in a modules build, vastly more efficient)
system: when we see an out-of-line definition of a virtual function, we check
whether that function was in fact its class's key function. (If so, we need to
emit the vtable.)
llvm-svn: 230830
When generating debug info for a static inline member which is initialized for
the DLLExport storage class, hoist the definition into a non-composite type
context. Otherwise, we would trigger an assertion when generating the DIE for
the associated global value as the debug context has a type association. This
addresses PR22669.
Thanks to David Blakie for help in coming up with a solution to this!
llvm-svn: 230816
Do not declare sized deallocation functions dependently on whether it is found in global scope. Instead, enforce the branching in emitted code by (1) declaring the functions extern_weak and (2) emitting sized delete expressions as a branching between both forms delete.
llvm-svn: 230580
It broke test/PCH/headersearch.cpp because it was using -Wpadding, which
only works for Itanium layout. Before this commit, we would use Itanium
record layout when using PCH, which is crazy. Now that the test uses an
explicit Itanium triple, we can reland.
llvm-svn: 230525
Covered by existing tests in test/CodeGen/override-layout.c and
test/CodeGenCXX/override-layout.cpp. Seriously, they found real bugs in
my code. :)
llvm-svn: 230446
This patch introduces the -fsanitize=cfi-vptr flag, which enables a control
flow integrity scheme that checks that virtual calls take place using a vptr of
the correct dynamic type. More details in the new docs/ControlFlowIntegrity.rst
file.
It also introduces the -fsanitize=cfi flag, which is currently a synonym for
-fsanitize=cfi-vptr, but will eventually cover all CFI checks implemented
in Clang.
Differential Revision: http://reviews.llvm.org/D7424
llvm-svn: 230055
MinGW neither imports nor exports such methods. The import bit was
committed earlier, in r221154, and this takes care of the export part.
This also partially fixes PR22591.
llvm-svn: 229922
Classes can be defined in multiple translation units. This means that
the static constexpr data members should have identical initializers in
all translation units. Implement this by giving the reference temporary
linkonce_odr linkage.
llvm-svn: 229900
extern "C" declarations should be considered like global declarations
for mangling purposes.
Differential Revision: http://reviews.llvm.org/D7718
llvm-svn: 229724
We attempted to be compatible with GCC's buggy mangling for templates
with a declaration for a template argument.
However, we weren't completely successful in copying their bug in cases
like:
char foo;
template <char &C> decltype(C) f() { return foo; };
template char &f<foo>();
Instead, just follow the ABI specification. This fixes PR22621.
llvm-svn: 229644
Our mangling of <destructor-name> wasn't quite right: we'd introduce
mangling substitutions where one shouldn't be possible. We also didn't
correctly handle the case where the destroyed type was not dependent but
still a TemplateSpecializationType.
N.B. There isn't a mangling for a template-template parameter showing up
as the destroyed type. We do the 'obvious' thing and mangle the index
of the parameter.
llvm-svn: 229615
We had two bugs:
- We were missing the "on" prefix for unresolved operators.
- We didn't handle the mangling of destructors at all.
This fixes PR22584.
llvm-svn: 229255
Matches the existing code for scalar default arguments. Complex default
arguments probably need the same handling too (test/fix to that coming
next).
llvm-svn: 228588
After r228258, Clang started emitting C++ EH IR that LLVM wasn't ready
to deal with, even when exceptions were disabled with /EHs-. This time,
make /EHs- turn off -fexceptions while still emitting exceptional
constructs in functions using __try. Since Sema rejects C++ exception
handling constructs before CodeGen, landingpads should only appear in
such functions as the result of a __try.
llvm-svn: 228329
initializer of the form {x}, where x is of type C or a type derived from C,
perform *non-list* initialization of the entity from x, but create a
CXXConstructExpr that knows that we used list-initialization syntax.
Plus some fixes to ensure we mangle correctly in this and related cases.
llvm-svn: 228276
It caused a chromium base unittest that tests throwing and catching SEH
exceptions to fail (http://crbug.com/455488) and I suspect it might also
be the cause of the chromium clang win 64-bit shared release builder timing
out during compiles. So revert to see if that's true.
llvm-svn: 228262
Now if you break on a dtor and go 'up' in your debugger (or you get an
asan failure in a dtor) during an exception unwind, you'll have more
context. Instead of all dtors appearing to be called from the '}' of the
function, they'll be attributed to the end of the scope of the variable,
the same as the non-exceptional dtor call.
This doesn't /quite/ remove all uses of CurEHLocation (which might be
nice to remove, for a few reasons) - it's still used to choose the
location for some other work in the landing pad. It'd be nice to
attribute that code to the same location as the exception calls within
the block and to remove CurEHLocation.
llvm-svn: 228181
We would synthesize memcpy intrinsics when emitting calls to trivial C++
constructors but we wouldn't take into account the alignment of the
destination.
llvm-svn: 228061
There are four major kinds of declarations that cause code generation:
- FunctionDecl (includes CXXMethodDecl etc)
- ObjCMethodDecl
- BlockDecl
- CapturedDecl
This patch tracks __try usage on FunctionDecls and diagnoses __try usage
in other decls. If someone wants to use __try from ObjC, they can use it
from a free function, since the ObjC code will need an ObjC-style EH
personality.
Eventually we will want to look through CapturedDecls and track SEH
usage on the parent FunctionDecl, if present.
llvm-svn: 228058
To handle default arguments in C++ in the debug info, we disable code
updating the debug location during the emission of default arguments.
This code was buggy in the case of default arguments which, themselves,
have default arguments - the inner default argument would re-enable
debug info when it was finished, but before the outer default argument
was finished.
This was already a bug, but got worse (because a crasher instead of just
a quality bug) with the recent improvements to debug info line quality
because... The ApplyDebugLocation scoped device would find the debug
info disabled and not save any debug location. But then in
~ApplyDebugLocation it would find the debug info had been enabled and
would then apply the no-location. Then the outer function call would be
emitted without any location. That's bad.
Arguably we could /also/ fix the ApplyDebugLocation to assert on this
situation (where debug info was disabled in the ctor and enabled in the
dtor, or the other way around) but this is at least the necessary fix
regardless.
(also, I imagine this disabling behavior might need to be in-place for
CGExprComplex and CGExprAgg too, maybe... ?)
And I seem to recall seeing some weird default arg stepping behavior
recently which might be related to this too... I'll have to look into
it.
llvm-svn: 228053
This is half a fix for a GDB test suite failure that expects to start at
'a' in the following code:
void func(int a)
if (a
&&
b)
...
But instead, without this change, the comparison was assigned to '&&'
(well, worse actually - because there was a chained 'a && b && c' and it
was assigned to the second '&&' because of a recursive application of
this bug) and then the load folded into the comparison so breaking on
the function started at '&&' instead of 'a'.
The other part of this needs to be fixed in LLVM where it's ignoring the
location of the icmp and instead using the location of the branch
instruction.
The fix to the conditional operator is actually a no-op currently,
because the conditional operator's location coincides with 'a' (the
start of the conditional expression) but should probably be '?' instead.
See the FIXME in the test case that mentions the ARCMigration tool
failures when I tried to make that change.
llvm-svn: 227356
clang currently calls MarkVTableUsed() for classes that get their virtual
methods called or that participate in a dynamic_cast. This is unnecessary,
since CodeGen only emits vtables when it generates constructor, destructor, and
vtt code. (*)
Note that Sema::MarkVTableUsed() doesn't cause the emission of a vtable.
Its main user-visible effect is that it instantiates virtual member functions
of template classes, to make sure that if codegen decides to write a vtable
all the entries in the vtable are defined.
While this shouldn't change the behavior of codegen (other than being faster),
it does make clang more permissive: virtual methods of templates (in particular
destructors) end up being instantiated less often. In particular, classes that
have members that are smart pointers to incomplete types will now get their
implicit virtual destructor instantiated less frequently. For example, this
used to not compile but does now compile:
template <typename T> struct OwnPtr {
~OwnPtr() { static_assert((sizeof(T) > 0), "TypeMustBeComplete"); }
};
class ScriptLoader;
struct Base { virtual ~Base(); };
struct Sub : public Base {
virtual void someFun() const {}
OwnPtr<ScriptLoader> m_loader;
};
void f(Sub *s) { s->someFun(); }
The more permissive behavior matches both gcc (where this is not often
observable, since in practice most things with virtual methods have a key
function, and Sema::DefineUsedVTables() skips vtables for classes with key
functions) and cl (which is my motivation for this change) – this fixes
PR20337. See this issue and the review thread for some discussions about
optimizations.
This is similar to r213109 in spirit. r225761 was a prerequisite for this
change.
Various tests relied on "a->f()" marking a's vtable as used (in the sema
sense), switch these to just construct a on the stack. This forces
instantiation of the implicit constructor, which will mark the vtable as used.
(*) The exception is -fapple-kext mode: In this mode, qualified calls to
virtual functions (`a->Base::f()`) still go through the vtable, and since the
vtable pointer off this doesn't point to Base's vtable, this needs to reference
Base's vtable directly. To keep this working, keep referencing the vtable for
virtual calls in apple kext mode.
llvm-svn: 227073
They are referenced from the vtable. (This worked fine, but I couldn't find
an existing test for this. Maybe I didn't look hard enough.)
llvm-svn: 227072
I broke this locally while working on PR20337 and no test caught that. Now
there's coverage for this, and a comment explaining why this is needed.
llvm-svn: 227068
lit.cfg has never supported running .C files, so these tests were never
executed by check-clang. Rename them to .cpp so that they run as part of
the test suite, and minorly tweak two of them that look like they were broken
when checked in to actually pass.
llvm-svn: 227029
This causes things like assignment to refer to the '=' rather than the
LHS when attributing the store instruction, for example.
There were essentially 3 options for this:
* The beginning of an expression (this was the behavior prior to this
commit). This meant that stepping through subexpressions would bounce
around from subexpressions back to the start of the outer expression,
etc. (eg: x + y + z would go x, y, x, z, x (the repeated 'x's would be
where the actual addition occurred)).
* The end of an expression. This seems to be what GCC does /mostly/, and
certainly this for function calls. This has the advantage that
progress is always 'forwards' (never jumping backwards - except for
independent subexpressions if they're evaluated in interesting orders,
etc). "x + y + z" would go "x y z" with the additions occurring at y
and z after the respective loads.
The problem with this is that the user would still have to think
fairly hard about precedence to realize which subexpression is being
evaluated or which operator overload is being called in, say, an asan
backtrace.
* The preferred location or 'exprloc'. In this case you get sort of what
you'd expect, though it's a bit confusing in its own way due to going
'backwards'. In this case the locations would be: "x y + z +" in
lovely postfix arithmetic order. But this does mean that if the op+
were an operator overload, say, and in a backtrace, the backtrace will
point to the exact '+' that's being called, not to the end of one of
its operands.
(actually the operator overload case doesn't work yet for other reasons,
but that's being fixed - but this at least gets scalar/complex
assignments and other plain operators right)
llvm-svn: 227027
In ItaniumCXXABI::EmitCXXDestructors we first emit the base destructor
and then try to emit the complete one as an alias.
If in the base ends up calling the complete destructor, the GD for the
complete will be in the list of deferred decl by the time we replace
it with an alias and delete the original GV.
llvm-svn: 226896
Currently we emit DeferredDeclsToEmit in reverse order. This patch changes that.
The advantages of the change are that
* The output order is a bit closer to the source order. The change to
test/CodeGenCXX/pod-member-memcpys.cpp is a good example.
* If we decide to deffer more, it will not cause as large changes in the
estcases as it would without this patch.
llvm-svn: 226751
This test will start failing shortly once this bug is fixed in LLVM. At
that point this behavior is no longer required in Clang and will be
removed. In the interim, remove this test just to avoid the race between
the LLVM and Clang commits.
After the LLVM commit, I'll cleanup the workaround behavior in Clang.
llvm-svn: 226735
This attribute implies indicates that the function musttail calls
another function and returns whatever it returns. The return type of the
thunk is meaningless, as the thunk can dynamically call different
functions with different return types. So long as the callers bitcast
the thunk with the correct type, behavior is well defined.
This attribute was necessary to fix PR20944, where the indirect call
combiner noticed that the thunk returned void and replaced the results
of the indirect call instruction with undef.
Over-the-shoulder reviewed by David Majnemer.
llvm-svn: 226707
This was causing some trouble for otherwise dead code removed in r225085
(reverted in r225361). The location being set for function arguments was
leaking out to the call which wasn't setting its own location (so a
quality bug turned into a crasher with r225085). Fix this so r225085 can
be recommitted.
llvm-svn: 226382
Emitting inlinable calls without debug locations (in functions with
debug info, to functions with debug info) is problematic for debug info
when inlining occurs. Test specifically that we don't do that in this
case - thus the test isn't simply "don't crash", it's "include debug
location for this call" (granted it's the wrong location - fix for that
is coming)
llvm-svn: 226337
This produces comdats for vtables, typeinfo, typeinfo names, and vtts.
When combined with llvm not producing implicit comdats, not doing this would
cause code bloat on ELF and link errors on COFF.
llvm-svn: 226227
Clang would previously become confused and crash here.
It does not make a lot of sense to export these, so warning seems appropriate.
MSVC will export some member functions for this kind of specializations, whereas
MinGW ignores the dllexport-edness. The latter behaviour seems better.
Differential Revision: http://reviews.llvm.org/D6984
llvm-svn: 226208
NAKAMURA Takumi