Instead of framing the interface around whether the variable is an ICE
(which is only interesting in C++98), primarily track whether the
initializer is a constant initializer (which is interesting in all C++
language modes).
No functionality change intended.
for which it matters.
This is a step towards separating checking for a constant initializer
(in which std::is_constant_evaluated returns true) and any other
evaluation of a variable initializer (in which it returns false).
This reverts commits 683b308c07bf827255fe1403056413f790e03729 and
8487bfd4e9ae186f9f588ef989d27a96cc2438c9.
We will go for a more restricted approach that does not give freedom to
everyone to change ABIs on whichever platform.
See the discussion on https://reviews.llvm.org/D85802.
This implements the flag proposed in RFC http://lists.llvm.org/pipermail/cfe-dev/2020-August/066437.html.
The goal is to add a way to override the default target C++ ABI through
a compiler flag. This makes it easier to test and transition between different
C++ ABIs through compile flags rather than build flags.
In this patch:
- Store `-fc++-abi=` in a LangOpt. This isn't stored in a
CodeGenOpt because there are instances outside of codegen where Clang
needs to know what the ABI is (particularly through
ASTContext::createCXXABI), and we should be able to override the
target default if the flag is provided at that point.
- Expose the existing ABIs in TargetCXXABI as values that can be passed
through this flag.
- Create a .def file for these ABIs to make it easier to check flag
values.
- Add an error for diagnosing bad ABI flag values.
Differential Revision: https://reviews.llvm.org/D85802
On some targets, preferred alignment is larger than ABI alignment in some cases. For example,
on AIX we have special power alignment rules which would cause that. Previously, to support
those cases, we added a “PreferredAlignment” field in the `RecordLayout` to store the AIX
special alignment values in “PreferredAlignment” as the community suggested.
However, that patch alone is not enough. There are places in the Clang where `PreferredAlignment`
should have been used instead of ABI-specified alignment. This patch is aimed at fixing those
spots.
Differential Revision: https://reviews.llvm.org/D86790
On the frontend side, this patch recovers AIX static init implementation to
use the linkage type and function names Clang chooses for sinit related function.
On the backend side, this patch sets correct linkage and function names on aliases
created for sinit/sterm functions.
Differential Revision: https://reviews.llvm.org/D84534
Set the debug location for static init related functions(__dtor
and __finalize) so we can generate valid debug info on AIX by invoking
-g with clang or -debug-info-kind=limited with clang_cc1.
This also works for any other future targets who may use sinit and
sterm functions for static initialization, where a direct call to
dtor will be generated within finalize function body.
This patch also aims at validating that the debug info generated
is correct for AIX sinit related functions.
Differential Revision: https://reviews.llvm.org/D83702
Adds `CodeGen::getCXXDestructorImplicitParam`, to retrieve a C++ destructor's implicit parameter (after the "this" pointer) based on the ABI in the given CodeGenModule.
This will allow other frontends (Swift, for example) to easily emit calls to object destructors with correct ABI semantics and calling convetions.
This is needed for Swift C++ interop. Here's the corresponding Swift change: https://github.com/apple/swift/pull/32291
Differential Revision: https://reviews.llvm.org/D82392
On AIX, we use __atexit to register dtor functions rather than __cxa_atexit.
So a driver change is needed to default AIX to using -fno-use-cxa-atexit.
Windows platform does not uses __cxa_atexit either. Following its precedent,
we remove the assertion for when -fuse-cxa-atexit is specified by the user,
do not produce a message and silently default to -fno-use-cxa-atexit behavior.
Differential Revision: https://reviews.llvm.org/D82136
1. Provides no piroirity supoort && disables three priority related
attributes: init_priority, ctor attr, dtor attr;
2. '-qunique' in XL compiler equivalent behavior of emitting sinit
and sterm functions name using getUniqueModuleId() util function
in LLVM (currently no support for InternalLinkage and WeakODRLinkage
symbols);
3. Add testcases to emit IR sample with __sinit80000000, __dtor, and
__sterm80000000;
4. Temporarily side-steps the need to implement the functionality of
llvm.global_ctors and llvm.global_dtors arrays. The uses of that
functionality in this patch (with respect to the name of the functions
involved) are not representative of how the functionality will be used
once implemented.
Differential Revision: https://reviews.llvm.org/D74166
This patch contains all of the clang changes from D72959.
- Generalize the relative vtables ABI such that it can be used by other targets.
- Add an enum VTableComponentLayout which controls whether components in the
vtable should be pointers to other structs or relative offsets to those structs.
Other ABIs can change this enum to restructure how components in the vtable
are laid out/accessed.
- Add methods to ConstantInitBuilder for inserting relative offsets to a
specified position in the aggregate being constructed.
- Fix failing tests under new PM and ASan and MSan issues.
See D72959 for background info.
Differential Revision: https://reviews.llvm.org/D77592
This reverts commit 2e009dbcb3e373a59e6e84dce6d51ae8a29f60a5.
Reverting since there were some test failures on buildbots that used the
new pass manager. ASan and MSan are also finding some bugs in this that
I'll need to address.
This patch contains all of the clang changes from D72959.
- Generalize the relative vtables ABI such that it can be used by other targets.
- Add an enum VTableComponentLayout which controls whether components in the
vtable should be pointers to other structs or relative offsets to those structs.
Other ABIs can change this enum to restructure how components in the vtable
are laid out/accessed.
- Add methods to ConstantInitBuilder for inserting relative offsets to a
specified position in the aggregate being constructed.
See D72959 for background info.
Differential Revision: https://reviews.llvm.org/D77592
Summary:
This patch upstreams support for a new storage only bfloat16 C type.
This type is used to implement primitive support for bfloat16 data, in
line with the Bfloat16 extension of the Armv8.6-a architecture, as
detailed here:
https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/arm-architecture-developments-armv8-6-a
The bfloat type, and its properties are specified in the Arm Architecture
Reference Manual:
https://developer.arm.com/docs/ddi0487/latest/arm-architecture-reference-manual-armv8-for-armv8-a-architecture-profile
In detail this patch:
- introduces an opaque, storage-only C-type __bf16, which introduces a new bfloat IR type.
This is part of a patch series, starting with command-line and Bfloat16
assembly support. The subsequent patches will upstream intrinsics
support for BFloat16, followed by Matrix Multiplication and the
remaining Virtualization features of the armv8.6-a architecture.
The following people contributed to this patch:
- Luke Cheeseman
- Momchil Velikov
- Alexandros Lamprineas
- Luke Geeson
- Simon Tatham
- Ties Stuij
Reviewers: SjoerdMeijer, rjmccall, rsmith, liutianle, RKSimon, craig.topper, jfb, LukeGeeson, fpetrogalli
Reviewed By: SjoerdMeijer
Subscribers: labrinea, majnemer, asmith, dexonsmith, kristof.beyls, arphaman, danielkiss, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D76077
Summary:
This is needed in Swift for C++ interop -- see here for the corresponding Swift change:
https://github.com/apple/swift/pull/30630
As part of this change, I've had to make some changes to the interface of CGCXXABI to return the additional parameters separately rather than adding them directly to a `CallArgList`.
Reviewers: rjmccall
Reviewed By: rjmccall
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D79942
This patch adds a matrix type to Clang as described in the draft
specification in clang/docs/MatrixSupport.rst. It introduces a new option
-fenable-matrix, which can be used to enable the matrix support.
The patch adds new MatrixType and DependentSizedMatrixType types along
with the plumbing required. Loads of and stores to pointers to matrix
values are lowered to memory operations on 1-D IR arrays. After loading,
the loaded values are cast to a vector. This ensures matrix values use
the alignment of the element type, instead of LLVM's large vector
alignment.
The operators and builtins described in the draft spec will will be added in
follow-up patches.
Reviewers: martong, rsmith, Bigcheese, anemet, dexonsmith, rjmccall, aaron.ballman
Reviewed By: rjmccall
Differential Revision: https://reviews.llvm.org/D72281
This reverts commit 61ba1481e200b5b35baa81ffcff81acb678e8508.
I'm reverting this because it breaks the lldb build with
incomplete switch coverage warnings. I would fix it forward,
but am not familiar enough with lldb to determine the correct
fix.
lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp:3958:11: error: enumeration values 'DependentExtInt' and 'ExtInt' not handled in switch [-Werror,-Wswitch]
switch (qual_type->getTypeClass()) {
^
lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp:4633:11: error: enumeration values 'DependentExtInt' and 'ExtInt' not handled in switch [-Werror,-Wswitch]
switch (qual_type->getTypeClass()) {
^
lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp:4889:11: error: enumeration values 'DependentExtInt' and 'ExtInt' not handled in switch [-Werror,-Wswitch]
switch (qual_type->getTypeClass()) {
Introduction/Motivation:
LLVM-IR supports integers of non-power-of-2 bitwidth, in the iN syntax.
Integers of non-power-of-two aren't particularly interesting or useful
on most hardware, so much so that no language in Clang has been
motivated to expose it before.
However, in the case of FPGA hardware normal integer types where the
full bitwidth isn't used, is extremely wasteful and has severe
performance/space concerns. Because of this, Intel has introduced this
functionality in the High Level Synthesis compiler[0]
under the name "Arbitrary Precision Integer" (ap_int for short). This
has been extremely useful and effective for our users, permitting them
to optimize their storage and operation space on an architecture where
both can be extremely expensive.
We are proposing upstreaming a more palatable version of this to the
community, in the form of this proposal and accompanying patch. We are
proposing the syntax _ExtInt(N). We intend to propose this to the WG14
committee[1], and the underscore-capital seems like the active direction
for a WG14 paper's acceptance. An alternative that Richard Smith
suggested on the initial review was __int(N), however we believe that
is much less acceptable by WG14. We considered _Int, however _Int is
used as an identifier in libstdc++ and there is no good way to fall
back to an identifier (since _Int(5) is indistinguishable from an
unnamed initializer of a template type named _Int).
[0]https://www.intel.com/content/www/us/en/software/programmable/quartus-prime/hls-compiler.html)
[1]http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2472.pdf
Differential Revision: https://reviews.llvm.org/D73967
This PR enables "XL" C++ ABI in frontend AST to IR codegen. And it is driven by
static init work. The current kind in Clang by default is Generic Itanium, which
has different behavior on static init with IBM xlclang compiler on AIX.
Differential Revision: https://reviews.llvm.org/D74015
This restores 59733525d37cf9ad88b5021b33ecdbaf2e18911c (D71913), along
with bot fix 19c76989bb505c3117730c47df85fd3800ea2767.
The bot failure should be fixed by D73418, committed as
af954e441a5170a75687699d91d85e0692929d43.
I also added a fix for non-x86 bot failures by requiring x86 in new test
lld/test/ELF/lto/devirt_vcall_vis_public.ll.
Summary:
Third part in series to support Safe Whole Program Devirtualization
Enablement, see RFC here:
http://lists.llvm.org/pipermail/llvm-dev/2019-December/137543.html
This patch adds type test metadata under -fwhole-program-vtables,
even for classes without hidden visibility. It then changes WPD to skip
devirtualization for a virtual function call when any of the compatible
vtables has public vcall visibility.
Additionally, internal LLVM options as well as lld and gold-plugin
options are added which enable upgrading all public vcall visibility
to linkage unit (hidden) visibility during LTO. This enables the more
aggressive WPD to kick in based on LTO time knowledge of the visibility
guarantees.
Support was added to all flavors of LTO WPD (regular, hybrid and
index-only), and to both the new and old LTO APIs.
Unfortunately it was not simple to split the first and second parts of
this part of the change (the unconditional emission of type tests and
the upgrading of the vcall visiblity) as I needed a way to upgrade the
public visibility on legacy WPD llvm assembly tests that don't include
linkage unit vcall visibility specifiers, to avoid a lot of test churn.
I also added a mechanism to LowerTypeTests that allows dropping type
test assume sequences we now aggressively insert when we invoke
distributed ThinLTO backends with null indexes, which is used in testing
mode, and which doesn't invoke the normal ThinLTO backend pipeline.
Depends on D71907 and D71911.
Reviewers: pcc, evgeny777, steven_wu, espindola
Subscribers: emaste, Prazek, inglorion, arichardson, hiraditya, MaskRay, dexonsmith, dang, davidxl, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D71913
Just marking a symbol as weak_odr/linkonce_odr isn't enough for
actually tolerating multiple copies of it at linking on windows,
it has to be made a proper comdat; make it comdat for all platforms
for consistency.
This should hopefully fix
https://bugzilla.mozilla.org/show_bug.cgi?id=1566288.
Differential Revision: https://reviews.llvm.org/D71572
Since 6bf108d77a3c, we try to not mark extern_weak symbols as
dso_local, to allow using COFF stubs for references to those symbols
(as the symbol may be missing, resolving to an absolute address zero,
outside of the current DSO).
Differential Revision: https://reviews.llvm.org/D71716
Currently, it is a modified version of the Itanium ABI, with the only
change being that constructors and destructors return 'this'.
Differential Revision: https://reviews.llvm.org/D70575
Remove dead virtual functions from vtables with
replaceNonMetadataUsesWith, so that CGProfile metadata gets cleaned up
correctly.
Original commit message:
Currently, it is hard for the compiler to remove unused C++ virtual
functions, because they are all referenced from vtables, which are referenced
by constructors. This means that if the constructor is called from any live
code, then we keep every virtual function in the final link, even if there
are no call sites which can use it.
This patch allows unused virtual functions to be removed during LTO (and
regular compilation in limited circumstances) by using type metadata to match
virtual function call sites to the vtable slots they might load from. This
information can then be used in the global dead code elimination pass instead
of the references from vtables to virtual functions, to more accurately
determine which functions are reachable.
To make this transformation safe, I have changed clang's code-generation to
always load virtual function pointers using the llvm.type.checked.load
intrinsic, instead of regular load instructions. I originally tried writing
this using clang's existing code-generation, which uses the llvm.type.test
and llvm.assume intrinsics after doing a normal load. However, it is possible
for optimisations to obscure the relationship between the GEP, load and
llvm.type.test, causing GlobalDCE to fail to find virtual function call
sites.
The existing linkage and visibility types don't accurately describe the scope
in which a virtual call could be made which uses a given vtable. This is
wider than the visibility of the type itself, because a virtual function call
could be made using a more-visible base class. I've added a new
!vcall_visibility metadata type to represent this, described in
TypeMetadata.rst. The internalization pass and libLTO have been updated to
change this metadata when linking is performed.
This doesn't currently work with ThinLTO, because it needs to see every call
to llvm.type.checked.load in the linkage unit. It might be possible to
extend this optimisation to be able to use the ThinLTO summary, as was done
for devirtualization, but until then that combination is rejected in the
clang driver.
To test this, I've written a fuzzer which generates random C++ programs with
complex class inheritance graphs, and virtual functions called through object
and function pointers of different types. The programs are spread across
multiple translation units and DSOs to test the different visibility
restrictions.
I've also tried doing bootstrap builds of LLVM to test this. This isn't
ideal, because only classes in anonymous namespaces can be optimised with
-fvisibility=default, and some parts of LLVM (plugins and bugpoint) do not
work correctly with -fvisibility=hidden. However, there are only 12 test
failures when building with -fvisibility=hidden (and an unmodified compiler),
and this change does not cause any new failures for either value of
-fvisibility.
On the 7 C++ sub-benchmarks of SPEC2006, this gives a geomean code-size
reduction of ~6%, over a baseline compiled with "-O2 -flto
-fvisibility=hidden -fwhole-program-vtables". The best cases are reductions
of ~14% in 450.soplex and 483.xalancbmk, and there are no code size
increases.
I've also run this on a set of 8 mbed-os examples compiled for Armv7M, which
show a geomean size reduction of ~3%, again with no size increases.
I had hoped that this would have no effect on performance, which would allow
it to awlays be enabled (when using -fwhole-program-vtables). However, the
changes in clang to use the llvm.type.checked.load intrinsic are causing ~1%
performance regression in the C++ parts of SPEC2006. It should be possible to
recover some of this perf loss by teaching optimisations about the
llvm.type.checked.load intrinsic, which would make it worth turning this on
by default (though it's still dependent on -fwhole-program-vtables).
Differential revision: https://reviews.llvm.org/D63932
llvm-svn: 375094
Currently, it is hard for the compiler to remove unused C++ virtual
functions, because they are all referenced from vtables, which are referenced
by constructors. This means that if the constructor is called from any live
code, then we keep every virtual function in the final link, even if there
are no call sites which can use it.
This patch allows unused virtual functions to be removed during LTO (and
regular compilation in limited circumstances) by using type metadata to match
virtual function call sites to the vtable slots they might load from. This
information can then be used in the global dead code elimination pass instead
of the references from vtables to virtual functions, to more accurately
determine which functions are reachable.
To make this transformation safe, I have changed clang's code-generation to
always load virtual function pointers using the llvm.type.checked.load
intrinsic, instead of regular load instructions. I originally tried writing
this using clang's existing code-generation, which uses the llvm.type.test
and llvm.assume intrinsics after doing a normal load. However, it is possible
for optimisations to obscure the relationship between the GEP, load and
llvm.type.test, causing GlobalDCE to fail to find virtual function call
sites.
The existing linkage and visibility types don't accurately describe the scope
in which a virtual call could be made which uses a given vtable. This is
wider than the visibility of the type itself, because a virtual function call
could be made using a more-visible base class. I've added a new
!vcall_visibility metadata type to represent this, described in
TypeMetadata.rst. The internalization pass and libLTO have been updated to
change this metadata when linking is performed.
This doesn't currently work with ThinLTO, because it needs to see every call
to llvm.type.checked.load in the linkage unit. It might be possible to
extend this optimisation to be able to use the ThinLTO summary, as was done
for devirtualization, but until then that combination is rejected in the
clang driver.
To test this, I've written a fuzzer which generates random C++ programs with
complex class inheritance graphs, and virtual functions called through object
and function pointers of different types. The programs are spread across
multiple translation units and DSOs to test the different visibility
restrictions.
I've also tried doing bootstrap builds of LLVM to test this. This isn't
ideal, because only classes in anonymous namespaces can be optimised with
-fvisibility=default, and some parts of LLVM (plugins and bugpoint) do not
work correctly with -fvisibility=hidden. However, there are only 12 test
failures when building with -fvisibility=hidden (and an unmodified compiler),
and this change does not cause any new failures for either value of
-fvisibility.
On the 7 C++ sub-benchmarks of SPEC2006, this gives a geomean code-size
reduction of ~6%, over a baseline compiled with "-O2 -flto
-fvisibility=hidden -fwhole-program-vtables". The best cases are reductions
of ~14% in 450.soplex and 483.xalancbmk, and there are no code size
increases.
I've also run this on a set of 8 mbed-os examples compiled for Armv7M, which
show a geomean size reduction of ~3%, again with no size increases.
I had hoped that this would have no effect on performance, which would allow
it to awlays be enabled (when using -fwhole-program-vtables). However, the
changes in clang to use the llvm.type.checked.load intrinsic are causing ~1%
performance regression in the C++ parts of SPEC2006. It should be possible to
recover some of this perf loss by teaching optimisations about the
llvm.type.checked.load intrinsic, which would make it worth turning this on
by default (though it's still dependent on -fwhole-program-vtables).
Differential revision: https://reviews.llvm.org/D63932
llvm-svn: 374539
The static analyzer is warning about potential null dereferences, but we should be able to use castAs<RecordType> directly and if not assert will fire for us.
llvm-svn: 373525
variable with non-trivial destruction.
We still need to invoke the thread wrapper to trigger registration of
the destructor call on thread shutdown.
llvm-svn: 373289
has a constexpr destructor.
For constexpr variables, reject if the variable does not have constant
destruction. In all cases, do not emit runtime calls to the destructor
for variables with constant destruction.
llvm-svn: 373159
Summary:
* Don't bother using a thread wrapper when the variable is known to
have constant initialization.
* Emit the thread wrapper as discardable-if-unused in TUs that don't
contain a definition of the thread_local variable.
* Don't emit the thread wrapper at all if the thread_local variable
is unused and discardable; it will be emitted by all TUs that need
it.
Reviewers: rjmccall, jdoerfert
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67429
llvm-svn: 371767
This patch adds the SVE built-in types defined by the Procedure Call
Standard for the Arm Architecture:
https://developer.arm.com/docs/100986/0000
It handles the types in all relevant places that deal with built-in types.
At the moment, some of these places bail out with an error, including:
(1) trying to generate LLVM IR for the types
(2) trying to generate debug info for the types
(3) trying to mangle the types using the Microsoft C++ ABI
(4) trying to @encode the types in Objective C
(1) and (2) are fixed by follow-on patches but (unlike this patch)
they deal mostly with target-specific LLVM details, so seemed like
a logically separate change. There is currently no spec for (3) and
(4), so reporting an error seems like the correct behaviour for now.
The intention is that the types will become sizeless types:
http://lists.llvm.org/pipermail/cfe-dev/2019-June/062523.html
The main purpose of the sizeless type extension is to diagnose
impossible or dangerous uses of the types, such as any that would
require sizeof to have a meaningful defined value.
Until then, the patch sets the alignments of the types to the values
specified in the link above. It also sets the sizes of the types to
zero, which is chosen to be consistently wrong and shouldn't affect
correctly-written code (i.e. code that would compile even with the
sizeless type extension).
The patch adds the common subset of functionality needed to test the
sizeless type extension on the one hand and to provide SVE intrinsic
functions on the other. After this patch, the two pieces of work are
essentially independent.
The patch is based on one by Graham Hunter:
https://reviews.llvm.org/D59245
Differential Revision: https://reviews.llvm.org/D62960
llvm-svn: 368413
Also, remove the final arg from ItaniumCXXABI in the PNaCl case since
its not needed.
Differential Revision: https://reviews.llvm.org/D64955
llvm-svn: 366518
Reason: this commit causes crashes in the clang compiler when building
LLVM Support with libc++, see https://bugs.llvm.org/show_bug.cgi?id=42665
for details.
llvm-svn: 366429
Summary:
This patch does mainly three things:
1. It fixes a false positive error detection in Sema that is similar to
D62156. The error happens when explicitly calling an overloaded
destructor for different address spaces.
2. It selects the correct destructor when multiple overloads for
address spaces are available.
3. It inserts the expected address space cast when invoking a
destructor, if needed, and therefore fixes a crash due to the unmet
assertion in llvm::CastInst::Create.
The following is a reproducer of the three issues:
struct MyType {
~MyType() {}
~MyType() __constant {}
};
__constant MyType myGlobal{};
kernel void foo() {
myGlobal.~MyType(); // 1 and 2.
// 1. error: cannot initialize object parameter of type
// '__generic MyType' with an expression of type '__constant MyType'
// 2. error: no matching member function for call to '~MyType'
}
kernel void bar() {
// 3. The implicit call to the destructor crashes due to:
// Assertion `castIsValid(op, S, Ty) && "Invalid cast!"' failed.
// in llvm::CastInst::Create.
MyType myLocal;
}
The added test depends on D62413 and covers a few more things than the
above reproducer.
Subscribers: yaxunl, Anastasia, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D64569
llvm-svn: 366422
Pass NULL to pointer arg of __cxa_atexit if addr space
is not matching with its param. This doesn't align yet
with how dtors are generated that should be changed too.
Differential Revision: https://reviews.llvm.org/D62413
llvm-svn: 366059
-fno-use-cxx-atexit is used
This matches the GCC behavior, __cxa_thread_atexit should be permissible
even though cxa_atexit is disabled.
Differential Revision: https://reviews.llvm.org/D63283/
llvm-svn: 363288
Darwin if the version of libc++abi isn't new enough to include the fix
in r319123
This patch resurrects r264998, which was committed to work around a bug
in libc++abi that was causing _cxa_allocate_exception to return a memory
that wasn't double-word aligned.
http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20160328/154332.html
In addition, this patch makes clang issue a warning if the type of the
thrown object requires an alignment that is larger than the minimum
guaranteed by the target C++ runtime.
rdar://problem/49864414
Differential Revision: https://reviews.llvm.org/D61667
llvm-svn: 360404
