When T is a class type, only nvsize(T) bytes need be accessible through
the reference. We had matching bugs in the application of the
dereferenceable attribute and in -fsanitize=undefined.
First attempt at implementing -fsemantic-interposition.
Rely on GlobalValue::isInterposable that already captures most of the expected
behavior.
Rely on a ModuleFlag to state whether we should respect SemanticInterposition or
not. The default remains no.
So this should be a no-op if -fsemantic-interposition isn't used, and if it is,
isInterposable being already used in most optimisation, they should honor it
properly.
Note that it only impacts architecture compiled with -fPIC and no pie.
Differential Revision: https://reviews.llvm.org/D72829
For non direct methods, the codegen uses the type of the Implementation.
Because Objective-C rules allow some differences between the Declaration
and Implementation return types, when the Implementation is in this
translation unit, the type of the Implementation should be preferred to
emit the Function over the Declaration.
Radar-Id: rdar://problem/58797748
Signed-off-by: Pierre Habouzit <phabouzit@apple.com>
Differential Revision: https://reviews.llvm.org/D73208
regions.
If the lastprivate conditional is passed as shared in inner region, we
shall check if it was ever changed and use this updated value after exit
from the inner region as an update value.
The constrained fcmp intrinsics don't allow the TRUE/FALSE predicates.
Using them will assert. To workaround this I'm emitting the old X86 specific intrinsics that were never removed from the backend when we switched to using fcmp in IR. We have no way to mark them as being strict, but that's true of all target specific intrinsics so doesn't seem like we need to solve that here.
I've also added support for selecting between signaling and quiet.
Still need to support SAE which will require using a target specific
intrinsic. Also need to fix masking to not use an AND instruction
after the compare.
Differential Revision: https://reviews.llvm.org/D72906
Summary:
Currently, sqdmulh_lane and friends from the ACLE (implemented in arm_neon.h),
are represented in LLVM IR as a (by vector) sqdmulh and a vector of (repeated)
indices, like so:
%shuffle = shufflevector <4 x i16> %v, <4 x i16> undef, <4 x i32> <i32 3, i32 3, i32 3, i32 3>
%vqdmulh2.i = tail call <4 x i16> @llvm.aarch64.neon.sqdmulh.v4i16(<4 x i16> %a, <4 x i16> %shuffle)
When %v's values are known, the shufflevector is optimized away and we are no
longer able to select the lane variant of sqdmulh in the backend.
This defeats a (hand-coded) optimization that packs several constants into a
single vector and uses the lane intrinsics to reduce register pressure and
trade-off materialising several constants for a single vector load from the
constant pool, like so:
int16x8_t v = {2,3,4,5,6,7,8,9};
a = vqdmulh_laneq_s16(a, v, 0);
b = vqdmulh_laneq_s16(b, v, 1);
c = vqdmulh_laneq_s16(c, v, 2);
d = vqdmulh_laneq_s16(d, v, 3);
[...]
In one microbenchmark from libjpeg-turbo this accounts for a 2.5% to 4%
performance difference.
We could teach the compiler to recover the lane variants, but this would likely
require its own pass. (Alternatively, "volatile" could be used on the constants
vector, but this is a bit ugly.)
This patch instead implements the following LLVM IR intrinsics for AArch64 to
maintain the original structure through IR optmization and into instruction
selection:
- sqdmulh_lane
- sqdmulh_laneq
- sqrdmulh_lane
- sqrdmulh_laneq.
These 'lane' variants need an additional register class. The second argument
must be in the lower half of the 64-bit NEON register file, but only when
operating on i16 elements.
Note that the existing patterns for shufflevector and sqdmulh into sqdmulh_lane
(etc.) remain, so code that does not rely on NEON intrinsics to generate these
instructions is not affected.
This patch also changes clang to emit these IR intrinsics for the corresponding
NEON intrinsics (AArch64 only).
Reviewers: SjoerdMeijer, dmgreen, t.p.northover, rovka, rengolin, efriedma
Reviewed By: efriedma
Subscribers: kristof.beyls, hiraditya, jdoerfert, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D71469
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.
This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.
This doesn't actually modify StringRef yet, I'll do that in a follow-up.
When using -fno-builtin[-<name>], we don't attach the IR attributes to
function definitions with no Decl, like the ones created through
`CreateGlobalInitOrDestructFunction`.
This results in projects using -fno-builtin or -ffreestanding to start
seeing symbols like _memset_pattern16.
The fix changes the behavior to always add the attribute if LangOptions
requests it.
Differential Revision: https://reviews.llvm.org/D73495
Performing a cast where the result is ignored caused Clang to crash when
performing codegen for the conversion:
_Complex int a;
void fn1() { (_Complex double) a; }
This patch addresses the crash by not trying to emit the scalar conversions,
causing it to be a noop. Fixes PR44624.
regions with reductions, lastprivates or linears clauses.
If the lastprivate conditional variable is updated in inner parallel
region with reduction, lastprivate or linear clause, the value must be
considred as a candidate for lastprivate conditional. Also, tracking in
inner parallel regions is not required.
This restores 59733525d3 (D71913), along
with bot fix 19c76989bb.
The bot failure should be fixed by D73418, committed as
af954e441a.
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:
The MicrosoftCXXABI uses a separate mechanism for emitting vtable
type metadata, and thus didn't pick up the change from D71907
to emit the vcall_visibility metadata under -fwhole-program-vtables.
I believe this is the cause of a Windows bot failure when I committed
follow on change D71913 that required a revert. The failure occurred
in a CFI test that was expecting to not abort because it expected a
devirtualization to occur, and without the necessary vcall_visibility
metadata we would not get devirtualization.
Note in the equivalent code in CodeGenModule::EmitVTableTypeMetadata
(used by the ItaniumCXXABI), we also emit the vcall_visibility metadata
when Virtual Function Elimination is enabled. Since I am not as familiar
with the details of that optimization, I have marked that as a TODO and
am only inserting under -fwhole-program-vtables.
Reviewers: evgeny777
Subscribers: Prazek, ostannard, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D73418
The only part of ASTContext.h that requires most AST types to be
complete is the parent map. Nothing in Clang proper uses the ParentMap,
so split it out into its own class. Make ASTContext own the
ParentMapContext so there is still a one-to-one relationship.
After this change, 562 fewer files depend on ASTTypeTraits.h, and 66
fewer depend on TypeLoc.h:
$ diff -u deps-before.txt deps-after.txt | \
grep '^[-+] ' | sort | uniq -c | sort -nr | less
562 - ../clang/include/clang/AST/ASTTypeTraits.h
340 + ../clang/include/clang/AST/ParentMapContext.h
66 - ../clang/include/clang/AST/TypeLocNodes.def
66 - ../clang/include/clang/AST/TypeLoc.h
15 - ../clang/include/clang/AST/TemplateBase.h
...
I computed deps-before.txt and deps-after.txt with `ninja -t deps`.
This removes a common and key dependency on TemplateBase.h and
TypeLoc.h.
This also has the effect of breaking the ParentMap RecursiveASTVisitor
instantiation into its own file, which roughly halves the compilation
time of ASTContext.cpp (29.75s -> 17.66s). The new file takes 13.8s to
compile.
I left behind forwarding methods for getParents(), but clients will need
to include a new header to make them work:
#include "clang/AST/ParentMapContext.h"
I noticed that this parent map functionality is unfortunately duplicated
in ParentMap.h, which only works for Stmt nodes.
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D71313
Summary:
This is a follow up on https://reviews.llvm.org/D71473#inline-647262.
There's a caveat here that `Align(1)` relies on the compiler understanding of `Log2_64` implementation to produce good code. One could use `Align()` as a replacement but I believe it is less clear that the alignment is one in that case.
Reviewers: xbolva00, courbet, bollu
Subscribers: arsenm, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, jrtc27, atanasyan, jsji, Jim, kerbowa, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D73099
Summary:
This was reverted in e45fcfc3aa due to
libcxx build failure. This revision addresses that case.
Original commit message:
This patch will provide support for auto return type for the C++ member
functions.
This patch includes clang side implementation of this feature.
Patch by: Awanish Pandey <Awanish.Pandey@amd.com>
Reviewers: dblaikie, aprantl, shafik, alok, SouraVX, jini.susan.george
Reviewed by: dblaikie
Differential Revision: https://reviews.llvm.org/D70524
If we do, then the property_list_t length is wrong
and class_getProperty gets very sad.
Signed-off-by: Pierre Habouzit <phabouzit@apple.com>
Radar-Id: rdar://problem/58804805
Differential Revision: https://reviews.llvm.org/D73219
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
MSVC 2013 would refuse to pass highly aligned things (typically vectors
and aggregates) by value. Users would receive this error:
t.cpp(11) : error C2719: 'w': formal parameter with __declspec(align('32')) won't be aligned
t.cpp(11) : error C2719: 'q': formal parameter with __declspec(align('32')) won't be aligned
However, in MSVC 2015, this behavior was changed, and highly aligned
things are now passed indirectly. To avoid breaking backwards
incompatibility, objects that do not have a *required* high alignment
(i.e. double) are still passed directly, even though they are not
naturally aligned. This change implements the new behavior of passing
things indirectly.
The new behavior is:
- up to three vector parameters can be passed in [XYZ]MM0-2
- remaining arguments with required alignment greater than 4 bytes are
passed indirectly
Previously, MSVC never passed things truly indirectly, meaning clang
would always apply the byval attribute to indirect arguments. We had to
go to the trouble of adding inalloca so that non-trivially copyable C++
types could be passed in place without copying the object
representation. When inalloca was added, we asserted that all arguments
passed indirectly must use byval. With this change, that assert no
longer holds, and I had to update inalloca to handle that case. The
implicit sret pointer parameter was already handled this way, and this
change generalizes some of that logic to arguments.
There are two cases that this change leaves unfixed:
1. objects that are non-trivially copyable *and* overaligned
2. vectorcall + inalloca + vectors
For case 1, I need to touch C++ ABI code in MicrosoftCXXABI.cpp, so I
want to do it in a follow-up.
For case 2, my fix is one line, but it will require updating IR tests to
use lots of inreg, so I wanted to separate it out.
Related to D71915 and D72110
Fixes most of PR44395
Reviewed By: rjmccall, craig.topper, erichkeane
Differential Revision: https://reviews.llvm.org/D72114
Summary:
Much like with the previous patch (D73005) with `AssumeAlignedAttr`
handling, results in mildly more readable IR,
and will improve test coverage in upcoming patch.
Note that in `AllocAlignAttr`'s case, there is no requirement
for that alignment parameter to end up being an I-C-E.
Reviewers: erichkeane, jdoerfert, hfinkel, aaron.ballman, rsmith
Reviewed By: erichkeane
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D73006
Summary:
This should be mostly NFC - we still lower the same alignment
knowledge to the IR. The main reasoning here is that
this somewhat improves readability of IR like this,
and will improve test coverage in upcoming patch.
Even though the alignment is guaranteed to always be an I-C-E,
we don't always materialize it as llvm's Alignment Attribute because:
1. There may be a non-zero offset
2. We may be sanitizing for alignment
Note that if there already was an IR alignment attribute
on return value, we union them, and thus the alignment
only ever rises.
Also, there is a second relevant clang attribute `AllocAlignAttr`,
so that is why `AbstractAssumeAlignedAttrEmitter` is templated.
Reviewers: erichkeane, jdoerfert, hfinkel, aaron.ballman, rsmith
Reviewed By: erichkeane
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D73005
Summary:
First patch to support Safe Whole Program Devirtualization Enablement,
see RFC here: http://lists.llvm.org/pipermail/llvm-dev/2019-December/137543.html
Always emit !vcall_visibility metadata under -fwhole-program-vtables,
and not just for -fvirtual-function-elimination. The vcall visibility
metadata will (in a subsequent patch) be used to communicate to WPD
which vtables are safe to devirtualize, and we will optionally convert
the metadata to hidden visibility at link time. Subsequent follow on
patches will help enable this by adding vcall_visibility metadata to the
ThinLTO summaries, and always emit type test intrinsics under
-fwhole-program-vtables (and not just for vtables with hidden
visibility).
In order to do this safely with VFE, since for VFE all vtable loads must
be type checked loads which will no longer be the case, this patch adds
a new "Virtual Function Elim" module flag to communicate to GlobalDCE
whether to perform VFE using the vcall_visibility metadata.
One additional advantage of using the vcall_visibility metadata to drive
more WPD at LTO link time is that we can use the same mechanism to
enable more aggressive VFE at LTO link time as well. The link time
option proposed in the RFC will convert vcall_visibility metadata to
hidden (aka linkage unit visibility), which combined with
-fvirtual-function-elimination will allow it to be done more
aggressively at LTO link time under the same conditions.
Reviewers: pcc, ostannard, evgeny777, steven_wu
Subscribers: mehdi_amini, Prazek, hiraditya, dexonsmith, davidxl, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D71907
Summary: Just an NFC code cleanup i stumbled upon when stumbling through clang alignment attribute handling.
Reviewers: erichkeane, gchatelet, courbet, jdoerfert
Reviewed By: gchatelet
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D72993
Summary:
We shouldn't be just giving up if we find one of them
(like we currently do with `AssumeAlignedAttr`),
we should emit them all.
As the tests show, even if we materialized good knowledge
from `__attribute__((assume_aligned(32)`, it doesn't mean
`__attribute__((alloc_align([...])))` info won't be useful.
It might be, but that isn't given.
Reviewers: erichkeane, jdoerfert, aaron.ballman
Reviewed By: erichkeane
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D72979
When constrained floating point is enabled the SystemZ-specific builtins
don't use constrained intrinsics in some cases. Fix that.
Differential Revision: https://reviews.llvm.org/D72722
Summary:
This patch resumes the work of D16586.
According to the AAPCS, volatile bit-fields should
be accessed using containers of the widht of their
declarative type. In such case:
```
struct S1 {
short a : 1;
}
```
should be accessed using load and stores of the width
(sizeof(short)), where now the compiler does only load
the minimum required width (char in this case).
However, as discussed in D16586,
that could overwrite non-volatile bit-fields, which
conflicted with C and C++ object models by creating
data race conditions that are not part of the bit-field,
e.g.
```
struct S2 {
short a;
int b : 16;
}
```
Accessing `S2.b` would also access `S2.a`.
The AAPCS Release 2019Q1.1
(https://static.docs.arm.com/ihi0042/g/aapcs32.pdf)
section 8.1 Data Types, page 35, "Volatile bit-fields -
preserving number and width of container accesses" has been
updated to avoid conflict with the C++ Memory Model.
Now it reads in the note:
```
This ABI does not place any restrictions on the access widths
of bit-fields where the container overlaps with a non-bit-field member.
This is because the C/C++ memory model defines these as being separate
memory locations, which can be accessed by two threads
simultaneously. For this reason, compilers must be permitted to use a
narrower memory access width (including splitting the access
into multiple instructions) to avoid writing to a different memory location.
```
I've updated the patch D16586 to follow such behavior by verifying that we
only change volatile bit-field access when:
- it won't overlap with any other non-bit-field member
- we only access memory inside the bounds of the record
Regarding the number of memory accesses, that should be preserved, that will
be implemented by D67399.
Reviewers: rsmith, rjmccall, eli.friedman, ostannard
Subscribers: ostannard, kristof.beyls, cfe-commits, carwil, olista01
Tags: #clang
Differential Revision: https://reviews.llvm.org/D72932
Implement support for C++2a requires-expressions.
Re-commit after compilation failure on some platforms due to alignment issues with PointerIntPair.
Differential Revision: https://reviews.llvm.org/D50360
Currently there are 4 different mechanisms for controlling denormal
flushing behavior, and about as many equivalent frontend controls.
- AMDGPU uses the fp32-denormals and fp64-f16-denormals subtarget features
- NVPTX uses the nvptx-f32ftz attribute
- ARM directly uses the denormal-fp-math attribute
- Other targets indirectly use denormal-fp-math in one DAGCombine
- cl-denorms-are-zero has a corresponding denorms-are-zero attribute
AMDGPU wants a distinct control for f32 flushing from f16/f64, and as
far as I can tell the same is true for NVPTX (based on the attribute
name).
Work on consolidating these into the denormal-fp-math attribute, and a
new type specific denormal-fp-math-f32 variant. Only ARM seems to
support the two different flush modes, so this is overkill for the
other use cases. Ideally we would error on the unsupported
positive-zero mode on other targets from somewhere.
Move the logic for selecting the flush mode into the compiler driver,
instead of handling it in cc1. denormal-fp-math/denormal-fp-math-f32
are now both cc1 flags, but denormal-fp-math-f32 is not yet exposed as
a user flag.
-cl-denorms-are-zero, -fcuda-flush-denormals-to-zero and
-fno-cuda-flush-denormals-to-zero will be mapped to
-fp-denormal-math-f32=ieee or preserve-sign rather than the old
attributes.
Stop emitting the denorms-are-zero attribute for the OpenCL flag. It
has no in-tree users. The meaning would also be target dependent, such
as the AMDGPU choice to treat this as only meaning allow flushing of
f32 and not f16 or f64. The naming is also potentially confusing,
since DAZ in other contexts refers to instructions implicitly treating
input denormals as zero, not necessarily flushing output denormals to
zero.
This also does not attempt to change the behavior for the current
attribute. The LangRef now states that the default is ieee behavior,
but this is inaccurate for the current implementation. The clang
handling is slightly hacky to avoid touching the existing
denormal-fp-math uses. Fixing this will be left for a future patch.
AMDGPU is still using the subtarget feature to control the denormal
mode, but the new attribute are now emitted. A future change will
switch this and remove the subtarget features.
Extend -fxray-instrumentation-bundle to split function-entry and
function-exit into two separate options, so that it is possible to
instrument only function entry or only function exit. For use cases
that only care about one or the other this will save significant overhead
and code size.
Differential Revision: https://reviews.llvm.org/D72890
XRay allows tuning by minimum function size, but also always instruments
functions with loops in them. If the minimum function size is set to a
large value the loop instrumention ends up causing most functions to be
instrumented anyway. This adds a new flag, -fxray-ignore-loops, to disable
the loop detection logic.
Differential Revision: https://reviews.llvm.org/D72873
[this re-applies c0176916a4
with the correct commit message and phabricator link]
This addresses point 1 of PR44213.
https://bugs.llvm.org/show_bug.cgi?id=44213
The DW_AT_LLVM_sysroot attribute is used for Clang module debug info,
to allow LLDB to import a Clang module from source. Currently it is
part of each DW_TAG_module, however, it is the same for all modules in
a compile unit. It is more efficient and less ambiguous to store it
once in the DW_TAG_compile_unit.
This should have no effect on DWARF consumers other than LLDB.
Differential Revision: https://reviews.llvm.org/D71732
Richard Smith