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 c0176916a4824812d25a5a22c4ff7c95857b0cd6
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
Summary:
When compiling with -munwind-tables, the SEH filter funclet needs the uwtable
function attribute, which gets automatically added if we use
SetInternalFunctionAttributes. The filter funclet is internal so this seems
appropriate.
Reviewers: rnk
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D72786
This is a purely cosmetic change that is NFC in terms of the binary
output. I bugs me that I called the attribute DW_AT_LLVM_isysroot
since the "i" is an artifact of GCC command line option syntax
(-isysroot is in the category of -i options) and doesn't carry any
useful information otherwise.
This attribute only appears in Clang module debug info.
Differential Revision: https://reviews.llvm.org/D71722
This reverts commit 3d210ed3d1880c615776b07d1916edb400c245a6.
See https://reviews.llvm.org/D71082 for the patch and discussion that make it
possible to reapply this patch.
Summary:
The old pass manager separated speed optimization and size optimization
levels into two unsigned values. Coallescing both in an enum in the new
pass manager may lead to unintentional casts and comparisons.
In particular, taking a look at how the loop unroll passes were constructed
previously, the Os/Oz are now (==new pass manager) treated just like O3,
likely unintentionally.
This change disallows raw comparisons between optimization levels, to
avoid such unintended effects. As an effect, the O{s|z} behavior changes
for loop unrolling and loop unroll and jam, matching O2 rather than O3.
The change also parameterizes the threshold values used for loop
unrolling, primarily to aid testing.
Reviewers: tejohnson, davidxl
Reviewed By: tejohnson
Subscribers: zzheng, ychen, mehdi_amini, hiraditya, steven_wu, dexonsmith, dang, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D72547
Summary:
This change implements the expansion in two parts:
- Add a utility function emitAMDGPUPrintfCall() in LLVM.
- Invoke the above function from Clang CodeGen, when processing a HIP
program for the AMDGPU target.
The printf expansion has undefined behaviour if the format string is
not a compile-time constant. As a sufficient condition, the HIP
ToolChain now emits -Werror=format-nonliteral.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D71365
This reverts commit 921f871ac438175ca8fcfcafdfcfac4d7ddf3905 because it
causes libc++ code to trigger __warn_memset_zero_len.
See https://reviews.llvm.org/D71082.
Today the optimization is limited to:
- `[ClassName alloc]`
- `[self alloc]` when within a class method
However it means that when code is written this way:
```
@interface MyObject
- (id)copyWithZone:(NSZone *)zone
{
return [[self.class alloc] _initWith...];
}
@end
```
... then the optimization doesn't kick in and `+[NSObject alloc]` ends
up in IMP caches where it could have been avoided. It turns out that
`+alloc` -> `+[NSObject alloc]` is the most cached SEL/IMP pair in the
entire platform which is rather silly).
There's two theoretical risks allowing this optimization:
1. if the receiver is nil (which it can't be today), but it turns out
that `objc_alloc()`/`objc_alloc_init()` cope with a nil receiver,
2. if the `Clas` type for the receiver is a lie. However, for such a
code to work today (and not fail witn an unrecognized selector
anyway) you'd have to have implemented the `-alloc` **instance
method**.
Fortunately, `objc_alloc()` doesn't assume that the receiver is a
Class, it basically starts with a test that is similar to
`if (receiver->isa->bits & hasDefaultAWZ) { /* fastpath */ }`.
This bit is only set on metaclasses by the runtime, so if an instance
is passed to this function by accident, its isa will fail this test,
and `objc_alloc()` will gracefully fallback to `objc_msgSend()`.
The one thing `objc_alloc()` doesn't support is tagged pointer
instances. None of the tagged pointer classes implement an instance
method called `'alloc'` (actually there's a single class in the
entire Apple codebase that has such a method).
Differential Revision: https://reviews.llvm.org/D71682
Radar-Id: rdar://problem/58058316
Reviewed-By: Akira Hatanaka
Signed-off-by: Pierre Habouzit <phabouzit@apple.com>
Summary:
Before this change, X86_32ABIInfo::classifyArgument would be called
twice on vector arguments to vectorcall functions. This function has
side effects to track GPR register usage, and this would lead to
incorrect GPR usage in some cases. The specific case I noticed is from
running out of XMM registers with mixed FP and vector arguments and no
aggregates of any kind. Consider this prototype:
void __vectorcall vectorcall_indirect_vec(
double xmm0, double xmm1, double xmm2, double xmm3, double xmm4,
__m128 xmm5,
__m128 ecx,
int edx,
__m128 mem);
classifyArgument has no effects when called on a plain FP type, but when
called on a vector type, it modifies FreeRegs to model GPR consumption.
However, this should not happen during the vector call first pass.
I refactored the code to unify vectorcall HVA logic with regcall HVA
logic. The conventions pass HVAs in registers differently (expanded vs.
not expanded), but if they do not fit in registers, they both pass them
indirectly by address.
Reviewers: erichkeane, craig.topper
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D72110
For IR input files, we currently use LLVM diagnostic handler even the
compilation is from clang. As a result, we are not able to use -Rpass
to get the transformation reports. Some warnings are not handled
properly either: We found many mysterious warnings in our ThinLTO backend
compilations in SamplePGO and CSPGO. An example of the warning:
"warning: net/proto2/public/metadata_lite.h:51:21: 0.02% (1 / 4999)"
This turns out to be a warning by Wmisexpect, which is supposed to be
filtered out by default. But since the filter is in clang's
diagnostic hander, we emit these incomplete warnings from LLVM's
diagnostic handler.
This patch uses clang diagnostic handler for IR input files. We create
a fake backendconsumer just to install the diagnostic handler.
With this change, we will have proper handling of all the warnings and we can
use -Rpass* options in IR input files compilation.
Also note that with is patch, LLVM's diagnostic options, like
"-mllvm -pass-remarks=*", are no longer be able to get optimization remarks.
Differential Revision: https://reviews.llvm.org/D72523
There are no special virtual function handlers (like __cxa_pure_virtual)
defined for NVPTX target, so just emit such functions as null pointers
to prevent issues with linking and unresolved references.
Summary:
This patch adds an option to limit debug info by only emitting complete class
type information when its constructor is emitted. This applies to classes
that have nontrivial user defined constructors.
I implemented the option by adding another level to `DebugInfoKind`, and
a flag `-flimit-debug-info-constructor`.
Total object file size on Windows, compiling with RelWithDebInfo:
before: 4,257,448 kb
after: 2,104,963 kb
And on Linux
before: 9,225,140 kb
after: 4,387,464 kb
According to the Windows clang.pdb files, here is a list of types that are no
longer complete with this option enabled: https://reviews.llvm.org/P8182
Reviewers: rnk, dblaikie
Subscribers: aprantl, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D72427
Summary:
Previously, since these aggregates are > 2*XLen, Clang would think they
were being returned indirectly and thus would decrease the number of
available GPRs available by 1. For long argument lists this could lead
to a struct argument incorrectly being passed indirectly.
Reviewers: asb, lenary
Reviewed By: asb, lenary
Subscribers: luismarques, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, Jim, lenary, s.egerton, pzheng, sameer.abuasal, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D69590
The option will limit debug info by only emitting complete class
type information when its constructor is emitted.
This patch changes comparisons with LimitedDebugInfo to use the new
level instead.
Differential Revision: https://reviews.llvm.org/D72427
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
GCC supports the conditional operator on VectorTypes that acts as a
'select' in C++ mode. This patch implements the support. Types are
converted as closely to GCC's behavior as possible, though in a few
places consistency with our existing vector type support was preferred.
Note that this implementation is different from the OpenCL version in a
number of ways, so it unfortunately required a different implementation.
First, the SEMA rules and promotion rules are significantly different.
Secondly, GCC implements COND[i] != 0 ? LHS[i] : RHS[i] (where i is in
the range 0- VectorSize, for each element). In OpenCL, the condition is
COND[i] < 0 ? LHS[i]: RHS[i].
In the process of implementing this, it was also required to make the
expression COND ? LHS : RHS type dependent if COND is type dependent,
since the type is now dependent on the condition. For example:
T ? 1 : 2;
Is not typically type dependent, since the result can be deduced from
the operands. HOWEVER, if T is a VectorType now, it could change this
to a 'select' (basically a swizzle with a non-constant mask) with the 1
and 2 being promoted to vectors themselves.
While this is a change, it is NOT a standards incompatible change. Based
on my (and D. Gregor's, at the time of writing the code) reading of the
standard, the expression is supposed to be type dependent if ANY
sub-expression is type dependent.
Differential Revision: https://reviews.llvm.org/D71463
which is the default TLS model for non-PIC objects. This allows large/
many thread local variables or a compact/fast code in an executable.
Specification is same as that of GCC. For example, the code model
option precedes the TLS size option.
TLS access models other than local-exec are not changed. It means
supoort of the large code model is only in the local exec TLS model.
Patch By KAWASHIMA Takahiro (kawashima-fj <t-kawashima@fujitsu.com>)
Reviewers: dmgreen, mstorsjo, t.p.northover, peter.smith, ostannard
Reviewd By: peter.smith
Committed by: peter.smith
Differential Revision: https://reviews.llvm.org/D71688
Summary:
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
This fixes a regression introduced in
2b4fa5348ee157b6b1a1af44d0137ca8c7a71573 that caused us to emit
shutdown-time destruction for variables with ARC ownership, using
C++-specific functions that don't exist in C implementations.
In the backend, this feature is implemented with the function attribute
"patchable-function-entry". Both the attribute and XRay use
TargetOpcode::PATCHABLE_FUNCTION_ENTER, so the two features are
incompatible.
Reviewed By: ostannard, MaskRay
Differential Revision: https://reviews.llvm.org/D72222
This feature is generic. Make it applicable for AArch64 and X86 because
the backend has only implemented NOP insertion for AArch64 and X86.
Reviewed By: nickdesaulniers, aaron.ballman
Differential Revision: https://reviews.llvm.org/D72221
