Summary:
Because wasm control flow needs to be structured, using WinEH
instructions to support wasm EH brings several benefits. This patch
makes wasm EH uses Windows EH instructions, with some changes:
1. Because wasm uses a single catch block to catch all C++ exceptions,
this merges all catch clauses into a single catchpad, within which we
test the EH selector as in Itanium EH.
2. Generates a call to `__clang_call_terminate` in case a cleanup
throws. Wasm does not have a runtime to handle this.
3. In case there is no catch-all clause, inserts a call to
`__cxa_rethrow` at the end of a catchpad in order to unwind to an
enclosing EH scope.
Reviewers: majnemer, dschuff
Subscribers: jfb, sbc100, jgravelle-google, sunfish, cfe-commits
Differential Revision: https://reviews.llvm.org/D44931
llvm-svn: 333703
Ensure latest MPT decl has a MSInheritanceAttr when instantiating
templates, to avoid null MSInheritanceAttr deref in
CXXRecordDecl::getMSInheritanceModel().
See PR#37399 for repo / details.
Patch by Andrew Rogers!
Differential Revision: https://reviews.llvm.org/D46664
llvm-svn: 333680
MethodVFTableLocations in MigrosoftVTableContext contains canonicalized
decl. But, it's sometimes asked to lookup for non-canonicalized decl,
and that causes assertion failure, and compilation failure.
Fixes PR37481.
Patch by Taiju Tsuiki!
Differential Revision: https://reviews.llvm.org/D46929
llvm-svn: 332639
This is similar to the LLVM change https://reviews.llvm.org/D46290.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\@brief'); do perl -pi -e 's/\@brief //g' $i & done
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46320
llvm-svn: 331834
Found via codespell -q 3 -I ../clang-whitelist.txt
Where whitelist consists of:
archtype
cas
classs
checkk
compres
definit
frome
iff
inteval
ith
lod
methode
nd
optin
ot
pres
statics
te
thru
Patch by luzpaz! (This is a subset of D44188 that applies cleanly with a few
files that have dubious fixes reverted.)
Differential revision: https://reviews.llvm.org/D44188
llvm-svn: 329399
Summary:
The following class hierarchy requires that we be able to emit a
this-adjusting thunk for B::foo in C's vftable:
struct Incomplete;
struct A {
virtual A* foo(Incomplete p) = 0;
};
struct B : virtual A {
void foo(Incomplete p) override;
};
struct C : B { int c; };
This TU is valid, but lacks a definition of 'Incomplete', which makes it
hard to build a thunk for the final overrider, B::foo.
Before this change, Clang gives up attempting to emit the thunk, because
it assumes that if the parameter types are incomplete, it must be
emitting the thunk for optimization purposes. This is untrue for the MS
ABI, where the implementation of B::foo has no idea what thunks C's
vftable may require. Clang needs to emit the thunk without necessarily
having access to the complete prototype of foo.
This change makes Clang emit a musttail variadic call when it needs such
a thunk. I call these "unprototyped" thunks, because they only prototype
the "this" parameter, which must always come first in the MS C++ ABI.
These thunks work, but they create ugly LLVM IR. If the call to the
thunk is devirtualized, it will be a call to a bitcast of a function
pointer. Today, LLVM cannot inline through such a call, but I want to
address that soon, because we also use this pattern for virtual member
pointer thunks.
This change also implements an old FIXME in the code about reusing the
thunk's computed CGFunctionInfo as much as possible. Now we don't end up
computing the thunk's mangled name and arranging it's prototype up to
around three times.
Fixes PR25641
Reviewers: rjmccall, rsmith, hans
Subscribers: Prazek, cfe-commits
Differential Revision: https://reviews.llvm.org/D45112
llvm-svn: 329009
This re-lands r328845 with fixes for crbug.com/827810.
The initial motiviation was to hoist MethodVFTableLocation to global
scope so it could be forward declared.
In this patch, I noticed that MicrosoftVTableContext uses some risky
patterns. It has methods that return references to data stored in
DenseMaps. I've made some of them return by value for trivial structs
and I've moved some things into separate allocations.
llvm-svn: 329007
This allows forward declaring it so that we can add it to
MicrosoftMangleContext::mangleVirtualMemPtrThunk without including
VTableBuilder.h. That saves a hashtable lookup when emitting virtual
member pointer functions.
It also shortens a really long type name. This struct has "VFtable" in
the name, so it seems pretty unlikely that someone will assume it is
generally useful for non-MS C++ ABI stuff.
llvm-svn: 328845
ObjC and ObjC++ pass non-trivial structs in a way that is incompatible
with each other. For example:
typedef struct {
id f0;
__weak id f1;
} S;
// this code is compiled in c++.
extern "C" {
void foo(S s);
}
void caller() {
// the caller passes the parameter indirectly and destructs it.
foo(S());
}
// this function is compiled in c.
// 'a' is passed directly and is destructed in the callee.
void foo(S a) {
}
This patch fixes the incompatibility by passing and returning structs
with __strong or weak fields using the C ABI in C++ mode. __strong and
__weak fields in a struct do not cause the struct to be destructed in
the caller and __strong fields do not cause the struct to be passed
indirectly.
Also, this patch fixes the microsoft ABI bug mentioned here:
https://reviews.llvm.org/D41039?id=128767#inline-364710
rdar://problem/38887866
Differential Revision: https://reviews.llvm.org/D44908
llvm-svn: 328731
Summary:
Previously we tried too hard to uphold the fiction that destructor
variants work like they do on Itanium throughout the ABI-neutral parts
of clang. This lead to MS C++ ABI incompatiblities and other bugs. Now,
-mconstructor-aliases will no longer control this ABI detail, and clang
-cc1's LLVM IR output will be this much closer to the clang driver's.
Based on a patch by Zahira Ammarguellat:
https://reviews.llvm.org/D39063
I've tried to move the logic that Zahira added into MicrosoftCXXABI.cpp.
There is only one ABI-specific detail sticking out, and that is in
CodeGenModule::getAddrOfCXXStructor, where we collapse complete dtors to
base dtors in the MS ABI.
This fixes PR32990.
Reviewers: erichkeane, zahiraam, majnemer, rjmccall
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D44505
llvm-svn: 327732
No effective behavior change, just for cleanliness.
Analysis and typing by me, actual patch mostly by Reid.
Fixes PR36159.
https://reviews.llvm.org/D44223
llvm-svn: 326960
The indirect function argument is in alloca address space in LLVM IR. However,
during Clang codegen for C++, the address space of indirect function argument
should match its address space in the source code, i.e., default addr space, even
for indirect argument. This is because destructor of the indirect argument may
be called in the caller function, and address of the indirect argument may be
taken, in either case the indirect function argument is expected to be in default
addr space, not the alloca address space.
Therefore, the indirect function argument should be mapped to the temp var
casted to default address space. The caller will cast it to alloca addr space
when passing it to the callee. In the callee, the argument is also casted to the
default address space and used.
CallArg is refactored to facilitate this fix.
Differential Revision: https://reviews.llvm.org/D34367
llvm-svn: 326946
So I wrote a clang-tidy check to lint out redundant `isa`, `cast`, and
`dyn_cast`s for fun. This is a portion of what it found for clang; I
plan to do similar cleanups in LLVM and other subprojects when I find
time.
Because of the volume of changes, I explicitly avoided making any change
that wasn't highly local and obviously correct to me (e.g. we still have
a number of foo(cast<Bar>(baz)) that I didn't touch, since overloading
is a thing and the cast<Bar> did actually change the type -- just up the
class hierarchy).
I also tried to leave the types we were cast<>ing to somewhere nearby,
in cases where it wasn't locally obvious what we were dealing with
before.
llvm-svn: 326416
This is the next step in setting dso_local for COFF.
The patches changes setGVProperties to first set dllimport/dllexport
and changes a few cases that were setting dllimport/dllexport
manually. With this a few more GVs are marked dso_local.
llvm-svn: 326397
This change reduces the live range of the loaded function pointer,
resulting in a slight code size decrease (~10KB in clang), and also
improves the security of CFI for virtual calls by making it less
likely that the function pointer will be spilled, and ensuring that
it is not spilled across a function call boundary.
Fixes PR35353.
Differential Revision: https://reviews.llvm.org/D42725
llvm-svn: 324286
The 'trivial_abi' attribute can be applied to a C++ class, struct, or
union. It makes special functions of the annotated class (the destructor
and copy/move constructors) to be trivial for the purpose of calls and,
as a result, enables the annotated class or containing classes to be
passed or returned using the C ABI for the underlying type.
When a type that is considered trivial for the purpose of calls despite
having a non-trivial destructor (which happens only when the class type
or one of its subobjects is a 'trivial_abi' class) is passed to a
function, the callee is responsible for destroying the object.
For more background, see the discussions that took place on the mailing
list:
http://lists.llvm.org/pipermail/cfe-dev/2017-November/055955.htmlhttp://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20180101/thread.html#214043
rdar://problem/35204524
Differential Revision: https://reviews.llvm.org/D41039
llvm-svn: 324269
Under the Microsoft ABI, it is possible for an object not to have
a virtual table pointer of its own if all of its virtual functions
were introduced by virtual bases. In that case, we need to load the
vtable pointer from one of the virtual bases and perform the type
check using its type.
Differential Revision: https://reviews.llvm.org/D41036
llvm-svn: 320638
Summary:
The MS ABI convention is that the 'this' pointer on entry is the address
of the vfptr that was used to make the virtual method call. In other
words, the pointer on entry always points to the base subobject that
introduced the virtual method. Consider this hierarchy:
struct A { virtual void f() = 0; };
struct B { virtual void g() = 0; };
struct C : A, B {
void f() override;
void g() override;
};
On entry to C::g, [ER]CX will contain the address of C's B subobject,
and C::g will have to subtract sizeof(A) to recover a pointer to C.
Before this change, we applied this adjustment in the prologue and
stored the new value into the "this" local variable alloca used for
debug info. However, MSVC does not do this, presumably because it is
often profitable to fold the adjustment into later field accesses. This
creates a problem, because the debugger expects the variable to be
unadjusted. Unfortunately, CodeView doesn't have anything like DWARF
expressions for computing variables that aren't in the program anymore,
so we have to declare 'this' to be the unadjusted value if we want the
debugger to see the right value.
This has the side benefit that, in optimized builds, the 'this' pointer
will usually be available on function entry because it doesn't require
any adjustment.
Reviewers: hans
Subscribers: aprantl, cfe-commits
Differential Revision: https://reviews.llvm.org/D40109
llvm-svn: 318440
Fix PR32990 by effectively reverting r283063 and solving it a different
way.
We want to limit the hack to not replace equivalent available_externally
dtors specifically to libc++, which uses always_inline. It seems certain
versions of libc++ do not provide all the symbols that an explicit
template instantiation is expected to provide.
If we get to the code that forms a real alias, only *then* check if this
is available_externally, and do that by asking a better question, which
is "is this a declaration for the linker?", because *that's* what means
we can't form an alias to it.
As a follow-on simplification, remove the InEveryTU parameter. Its last
use guarded this code for forming aliases, but we should never form
aliases to declarations, regardless of what we know about every TU.
llvm-svn: 315656
constructors when deciding whether classes should be passed indirectly.
This fixes ABI differences between Clang and GCC:
* Previously, Clang ignored the move constructor when making this
determination. It now takes the move constructor into account, per
https://github.com/itanium-cxx-abi/cxx-abi/pull/17 (this change may
seem recent, but the ABI change was agreed on the Itanium C++ ABI
list a long time ago).
* Previously, Clang's behavior when the copy constructor was deleted
was unstable -- depending on whether the lazy declaration of the
copy constructor had been triggered, you might get different behavior.
We now eagerly declare the copy constructor whenever its deletedness
is unclear, and ignore deleted copy/move constructors when looking for
a trivial such constructor.
This also fixes an ABI difference between Clang and MSVC:
* If the copy constructor would be implicitly deleted (but has not been
lazily declared yet), for instance because the class has an rvalue
reference member, we would pass it directly. We now pass such a class
indirectly, matching MSVC.
Based on a patch by Vassil Vassilev, which was based on a patch by Bernd
Schmidt, which was based on a patch by Reid Kleckner!
This is a re-commit of r310401, which was reverted in r310464 due to ARM
failures (which should now be fixed).
llvm-svn: 310983
constructors when deciding whether classes should be passed indirectly.
This fixes ABI differences between Clang and GCC:
* Previously, Clang ignored the move constructor when making this
determination. It now takes the move constructor into account, per
https://github.com/itanium-cxx-abi/cxx-abi/pull/17 (this change may
seem recent, but the ABI change was agreed on the Itanium C++ ABI
list a long time ago).
* Previously, Clang's behavior when the copy constructor was deleted
was unstable -- depending on whether the lazy declaration of the
copy constructor had been triggered, you might get different behavior.
We now eagerly declare the copy constructor whenever its deletedness
is unclear, and ignore deleted copy/move constructors when looking for
a trivial such constructor.
This also fixes an ABI difference between Clang and MSVC:
* If the copy constructor would be implicitly deleted (but has not been
lazily declared yet), for instance because the class has an rvalue
reference member, we would pass it directly. We now pass such a class
indirectly, matching MSVC.
llvm-svn: 310401
The initializer for a static local variable cannot be hot, because it runs at
most once per program. That's not quite the same thing as having a low branch
probability, but under the assumption that the function is invoked many times,
modeling this as a branch probability seems reasonable.
For TLS variables, the situation is less clear, since the initialization side
of the branch can run multiple times in a program execution, but we still
expect initialization to be rare relative to non-initialization uses. It would
seem worthwhile to add a PGO counter along this path to make this estimation
more accurate in future.
For globals with guarded initialization, we don't yet apply any branch weights.
Due to our use of COMDATs, the guard will be reached exactly once per DSO, but
we have no idea how many DSOs will define the variable.
llvm-svn: 309195
In addition to the formal linkage rules, the Modules TS includes cases where
internal-linkage symbols within a module interface unit can be referenced from
outside the module via exported inline functions / templates. We give such
declarations "module-internal linkage", which is formally internal linkage, but
results in an externally-visible symbol.
llvm-svn: 307434
Summary:
If the first parameter of the function is the ImplicitParamDecl, codegen
automatically marks it as an implicit argument with `this` or `self`
pointer. Added internal kind of the ImplicitParamDecl to separate
'this', 'self', 'vtt' and other implicit parameters from other kind of
parameters.
Reviewers: rjmccall, aaron.ballman
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D33735
llvm-svn: 305075
Summary:
We can emit vtable definition having inline function
if they are all emitted.
Reviewers: rjmccall, rsmith
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D33437
llvm-svn: 304394
This patch makes use of the prefix/suffix ABI argument distinction that
was introduced in r295870, so that we now emit ExtParameterInfo at the
correct offset for member calls that have added ABI arguments. I don't
see a good way to test the generated param info, since we don't actually
seem to use it in CGFunctionInfo outside of Swift. Any
suggestions/thoughts for how to better test this are welcome. :)
This patch also fixes a small bug with inheriting constructors: if we
decide not to pass args into an base class ctor, we would still
generate ExtParameterInfo as though we did. The added test-case is for
that behavior.
llvm-svn: 296024
Meta: The ultimate goal is to teach ExtParameterInfo about
pass_object_size attributes. This is necessary for that, since our
ExtParameterInfo is a bit buggy in C++. I plan to actually make use of
this Prefix/Suffix info in the near future, but I like small
single-purpose changes. Especially when those changes are hard to
actually test...
At the moment, some of our C++-specific CodeGen pretends that ABIs can
only add arguments to the beginning of a function call. This isn't quite
correct: args can be appended to the end, as well. It hasn't mattered
much until now, since we seem to only use this "number of arguments
added" data when calculating the ExtParameterInfo to use when making a
CGFunctionInfo. Said ExtParameterInfo is currently only used for
ParameterABIs (Swift) and ns_consumed (ObjC).
So, this patch allows ABIs to indicate whether args they added were at
the beginning or end of an argument list. We can use this information to
emit ExtParameterInfos more correctly, though like said, that bit is
coming soon.
No tests since this is theoretically a nop.
llvm-svn: 295870
In ThinLTO mode, type metadata will require the module to be written as a
multi-module bitcode file, which is currently incompatible with the Darwin
linker. It is also useful to be able to enable or disable multi-module bitcode
for testing purposes. This introduces a cc1-level flag, -f{,no-}lto-unit,
which is used by the driver to enable multi-module bitcode on all but
Darwin+ThinLTO, and can also be used to enable/disable the feature manually.
Differential Revision: https://reviews.llvm.org/D28877
llvm-svn: 292448
The MS ABI RTTI has a reserved field which is used as a cache for the
demangled name. It must be zero-initialized, which is used as a hint by
the runtime to say that the cache has not been populated. Since this
field is populated at runtime, the RTTI structures must be placed in the
.data section rather than .rdata. NFC
llvm-svn: 290799
Properly attribute DLL storage to runtime functions. When generating the
runtime function, scan for an existing declaration which may provide an explicit
declaration (local storage) or a DLL import or export storage from the user.
Honour that if available. Otherwise, if building with a local visibility of the
public or standard namespaces (-flto-visibility-public-std), give the symbols
local storage (it indicates a /MT[d] link, so static runtime). Otherwise,
assume that the link is dynamic, and give the runtime function dllimport
storage.
This allows for implementations to get the correct storage as long as they are
properly declared, the user to override the import storage, and in case no
explicit storage is given, use of the import storage.
llvm-svn: 289776
In a future change, this representation will allow us to use the new inrange
annotation on getelementptr to allow the optimizer to split vtable groups.
Differential Revision: https://reviews.llvm.org/D22296
llvm-svn: 289584
The problem only happen on window ( A MS-ABI issuer )
The nature of the problem is virtual base dtor called more than it is needed after exception throw in inheriting base class(with virtual bases) ctor.
The root problem is when throw happen, not all virtual base classes have been contructed, so not all virtual base dtors are need to call for ehcleanup.
clang has code to handle vbase initialization: basically add check for "complete object flag" before call to v-base ctor.
But that part is missing for cleanup code.
To fix this add similar code as v-base init to cleanup code, same algorithm.
1> Add new routine:
EmitDtorCompleteObjectHandler
With corresponding to EmitCtorCompleteObjectHandler
2> In the EmitDestructorCal
Call EmitDtorCompleteObjectHandler when generate ehcleanup inside ctor.
Just add check for "complete object flag" before call to v-base dtor.
Without my change:
ehcleanup: ; preds = %ctor.skip_vbases
%13 = cleanuppad within none [], !dbg !66
%14 = bitcast %struct.class_0* %this1 to i8*, !dbg !66
%15 = getelementptr inbounds i8, i8* %14, i64 8, !dbg !66
%16 = bitcast i8* %15 to %struct.class_2*, !dbg !66
call void @"\01??1class_2@@UEAA@XZ"(%struct.class_2* %16) #6 [ "funclet"(token
%13) ], !dbg !66
cleanupret from %13 unwind to caller, !dbg !66
with my change:
ehcleanup: ; preds = %ctor.skip_vbases
%13 = cleanuppad within none [], !dbg !66
%14 = bitcast %struct.class_0* %this1 to i8*, !dbg !66
%15 = getelementptr inbounds i8, i8* %14, i64 8, !dbg !66
%16 = bitcast i8* %15 to %struct.class_2*, !dbg !66
%is_complete_object4 = icmp ne i32 %is_most_derived2, 0, !dbg !66
br i1 %is_complete_object4, label %Dtor.dtor_vbase, label %Dtor.skip_vbase, !d
bg !66
Dtor.dtor_vbase: ; preds = %ehcleanup
call void @"\01??1class_2@@UEAA@XZ"(%struct.class_2* %16) #6 [ "funclet"(token
%13) ], !dbg !66
br label %Dtor.skip_vbase, !dbg !66
Dtor.skip_vbase: ; preds = %Dtor.dtor_vbase, %ehcleanup
cleanupret from %13 unwind to caller, !dbg !66
Please let me know you need more info.
Patch by Jennifer Yu.
Differential Revision: https://reviews.llvm.org/D27358
llvm-svn: 288869
Summary:
We don't need a side table in ASTContext to hold CXXDefaultArgExprs. The
important part of building the CXXDefaultArgExprs was to ODR use the
default argument expressions, not to make AST nodes. Refactor the code
to only check the default argument, and remove the side table in
ASTContext which wasn't being serialized.
Fixes PR31121
Reviewers: thakis, rsmith, majnemer
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D27007
llvm-svn: 287774
This is needed because whether the constructor is deleted can control whether
we pass structs by value directly.
To fix this properly we probably want a more direct way for CodeGen to ask
whether the constructor was deleted.
Fixes PR31049.
Differential Revision: https://reviews.llvm.org/D26822
llvm-svn: 287600
getClassAtVTableLocation hunts through virtual bases without using the
MDC layout which is indicative of a bug.
Instead, reuse the getVFPtrOffsets machinery to calculate which
subobject within the MDC is responsible for the vfptr.
Differential Revision: https://reviews.llvm.org/D25895
llvm-svn: 285315
abstract information about the callee. NFC.
The goal here is to make it easier to recognize indirect calls and
trigger additional logic in certain cases. That logic will come in
a later patch; in the meantime, I felt that this was a significant
improvement to the code.
llvm-svn: 285258
getClassAtVTableLocation() was calling
ASTRecordLayout::getBaseClassOffset() on a virtual base, causing an
assert.
Differential Revision: https://reviews.llvm.org/D25779
llvm-svn: 284624
Heejin Ahn