With -fpatchable-function-entry (or the patchable_function_entry
function attribute), we emit records of patchable entry locations to the
__patchable_function_entries section. Add an additional parameter to the
command line option that allows one to specify a different default
section name for the records, and an identical parameter to the function
attribute that allows one to override the section used.
The main use case for this change is the Linux kernel using prefix NOPs
for ftrace, and thus depending on__patchable_function_entries to locate
traceable functions. Functions that are not traceable currently disable
entry NOPs using the function attribute, but this creates a
compatibility issue with -fsanitize=kcfi, which expects all indirectly
callable functions to have a type hash prefix at the same offset from
the function entry.
Adding a section parameter would allow the kernel to distinguish between
traceable and non-traceable functions by adding entry records to
separate sections while maintaining a stable function prefix layout for
all functions. LKML discussion:
https://lore.kernel.org/lkml/Y1QEzk%2FA41PKLEPe@hirez.programming.kicks-ass.net/
This adds DWARF generation for fixed-point types. This feature is needed
by Ada.
Note that a pre-existing GNU extension is used in one case. This has
been emitted by GCC for years, and is needed because standard DWARF is
otherwise incapable of representing these types.
DenseSet, SmallPtrSet, SmallSet, SetVector, and StringSet recently
gained C++23-style insert_range. This patch uses insert_range with
iterator ranges. For each case, I've verified that foos is defined as
make_range(foo_begin(), foo_end()) or in a similar manner.
I initially thought starting with a more narrow definition and later
expanding would make more sense. But as pointed out in review for PR
#129220, this restriction is generating additional unnecessary work.
This patch alters the intrinsic to accept patterns of any type. Future
patches will update LoopIdiomRecognize and PreISelIntrinsicLowering to
take advantage of this. The verifier will complain if an unsized type is
used. I've additionally taken the opportunity to remove a comment from
the LangRef about some bit widths potentially not being supported by the
target. I don't think this is any more true than it is for arbitrary
width loads/stores which don't carry a similar warning that I can see.
A verifier check ensures that only sized types are used for the pattern.
The module currently stores the target triple as a string. This means
that any code that wants to actually use the triple first has to
instantiate a Triple, which is somewhat expensive. The change in #121652
caused a moderate compile-time regression due to this. While it would be
easy enough to work around, I think that architecturally, it makes more
sense to store the parsed Triple in the module, so that it can always be
directly queried.
For this change, I've opted not to add any magic conversions between
std::string and Triple for backwards-compatibilty purses, and instead
write out needed Triple()s or str()s explicitly. This is because I think
a decent number of them should be changed to work on Triple as well, to
avoid unnecessary conversions back and forth.
The only interesting part in this patch is that the default triple is
Triple("") instead of Triple() to preserve existing behavior. The former
defaults to using the ELF object format instead of unknown object
format. We should fix that as well.
`llvm.wasm.throw` intrinsic can throw but it was not invokable. Not sure
what the rationale was when it was first written that way, but I think
at least in Emscripten's C++ exception support with the Wasm port of
libunwind, `__builtin_wasm_throw`, which is lowered down to
`llvm.wasm.rethrow`, is used only within `_Unwind_RaiseException`, which
is an one-liner and thus does not need an `invoke`:
720e97f76d/system/lib/libunwind/src/Unwind-wasm.c (L69)
(`_Unwind_RaiseException` is called by `__cxa_throw`, which is generated
by the `throw` C++ keyword)
But this does not address other direct uses of the builtin in C++, whose
use I'm not sure about but is not prohibited. Also other language
frontends may need to use the builtin in different functions, which has
`try`-`catch`es or destructors.
This makes `llvm.wasm.throw` invokable in the backend. To do that, this
adds a custom lowering routine to `SelectionDAGBuilder::visitInvoke`,
like we did for `llvm.wasm.rethrow`.
This does not generate `invoke`s for `__builtin_wasm_throw` yet, which
will be done by a follow-up PR.
Addresses #124710.
An Ada program can have types that are subranges of other types. This
patch adds a new DIType node, DISubrangeType, to represent this concept.
I considered extending the existing DISubrange to do this, but as
DISubrange does not derive from DIType, that approach seemed more
disruptive.
A DISubrangeType can be used both as an ordinary type, but also as the
type of an array index. This is also important for Ada.
Ada subrange types can also be stored using a bias. Representing this in
the DWARF required the use of an extension. GCC has been emitting this
extension for years, so I've reused it here.
Check that the input register is an inreg argument to the parent
function. (See the comment in `IntrinsicsAMDGPU.td`.)
This LLVM defect was identified via the AMD Fuzzing project.
---------
Co-authored-by: Matt Arsenault <arsenm2@gmail.com>
Make sure that this intrinsic is being followed by unreachable.
This LLVM defect was identified via the AMD Fuzzing project.
Thanks to @rovka for helping me solve this issue!
As part of the "RemoveDIs" work to eliminate debug intrinsics, we're
replacing methods that use Instruction*'s as positions with iterators. The
call-sites updated in this patch are those where the dyn_cast_or_null cast
utility doesn't compose well with iterator insertion. It can distinguish
between nullptr and a "present" (non-null) Instruction pointer, but not
between a legal and illegal instruction iterator. This can lead to
end-iterator dereferences and thus crashes.
We can improve this in the future (as parent-pointers can now be accessed
from ilist nodes), but for the moment, add explicit tests for end()
iterators at the five call sites affected by this.
As part of the "RemoveDIs" project, BasicBlock::iterator now carries a
debug-info bit that's needed when getFirstNonPHI and similar feed into
instruction insertion positions. Call-sites where that's necessary were
updated a year ago; but to ensure some type safety however, we'd like to
have all calls to getFirstNonPHI use the iterator-returning version.
This patch changes a bunch of call-sites calling getFirstNonPHI to use
getFirstNonPHIIt, which returns an iterator. All these call sites are
where it's obviously safe to fetch the iterator then dereference it. A
follow-up patch will contain less-obviously-safe changes.
We'll eventually deprecate and remove the instruction-pointer
getFirstNonPHI, but not before adding concise documentation of what
considerations are needed (very few).
---------
Co-authored-by: Stephen Tozer <Melamoto@gmail.com>
This remove some erroneous debug info from tests that should address the
test failures that showed up when the this was previously committed.
This reverts commit 6716ce8b641f0e42e2343e1694ee578b027be0c4.
Came up recently with some nodebug case on codeview, that caused a null
entry in elements and crashed LLVM.
Original clang fix to avoid generating IR like this: 504dd577675e8c85cdc8525990a7c8b517a38a89
This makes sure no optimizations are applied that assume the
bigger alignment or size, which could be incorrect if we link
together with non-instrumented code.
Verify the format is valid and the type is one of the expected
i32 vectors. Verify the used vector types at least cover the
requirements of the corresponding format operand.
Add a property to allow marking target extension types that cannot be
used in an alloca instruction or byval argument, similar to CanBeGlobal
for global variables.
---------
Co-authored-by: Nikita Popov <github@npopov.com>
Improve the information printed when -memprof-report-hinted-sizes is
enabled. Now print the full context hash computed from the original
profile, similar to what we do when reporting matching statistics. This
will make it easier to correlate with the profile.
Note that the full context hash must be computed at profile match time
and saved in the metadata and summary, because we may trim the context
during matching when it isn't needed for distinguishing hotness.
Similarly, due to the context trimming, we may have more than one full
context id and total size pair per MIB in the metadata and summary,
which now get a list of these pairs.
Remove the old aggregate size from the metadata and summary support.
One other change from the prior support is that we no longer write the
size information into the combined index for the LTO backends, which
don't use this information, which reduces unnecessary bloat in
distributed index files.
Relands 7ff3a9acd84654c9ec2939f45ba27f162ae7fbc3 after regenerating the
test case.
Supersedes the draft PR #94992, taking a different approach following
feedback:
* Lower in PreISelIntrinsicLowering
* Don't require that the number of bytes to set is a compile-time
constant
* Define llvm.memset_pattern rather than llvm.memset_pattern.inline
As discussed in the [RFC
thread](https://discourse.llvm.org/t/rfc-introducing-an-llvm-memset-pattern-inline-intrinsic/79496),
the intent is that the intrinsic will be lowered to loops, a sequence of
stores, or libcalls depending on the expected cost and availability of
libcalls on the target. Right now, there's just a single lowering path
that aims to handle all cases. My intent would be to follow up with
additional PRs that add additional optimisations when possible (e.g.
when libcalls are available, when arguments are known to be constant
etc).
This reverts commit 7ff3a9acd84654c9ec2939f45ba27f162ae7fbc3.
Recent scheduling changes means tests need to be re-generated. Reverting
to green while I do that.
Supersedes the draft PR #94992, taking a different approach following
feedback:
* Lower in PreISelIntrinsicLowering
* Don't require that the number of bytes to set is a compile-time
constant
* Define llvm.memset_pattern rather than llvm.memset_pattern.inline
As discussed in the [RFC
thread](https://discourse.llvm.org/t/rfc-introducing-an-llvm-memset-pattern-inline-intrinsic/79496),
the intent is that the intrinsic will be lowered to loops, a sequence of
stores, or libcalls depending on the expected cost and availability of
libcalls on the target. Right now, there's just a single lowering path
that aims to handle all cases. My intent would be to follow up with
additional PRs that add additional optimisations when possible (e.g.
when libcalls are available, when arguments are known to be constant
etc).
This patch introduces an experimental intrinsic for matching the
elements of one vector against the elements of another.
For AArch64 targets that support SVE2, the intrinsic lowers to a MATCH
instruction for supported fixed and scalar vector types.
# What
This PR renames the newly-introduced llvm attribute
`sanitize_realtime_unsafe` to `sanitize_realtime_blocking`. Likewise,
sibling variables such as `SanitizeRealtimeUnsafe` are renamed to
`SanitizeRealtimeBlocking` respectively. There are no other functional
changes.
# Why?
- There are a number of problems that can cause a function to be
real-time "unsafe",
- we wish to communicate what problems rtsan detects and *why* they're
unsafe, and
- a generic "unsafe" attribute is, in our opinion, too broad a net -
which may lead to future implementations that need extra contextual
information passed through them in order to communicate meaningful
reasons to users.
- We want to avoid this situation and make the runtime library boundary
API/ABI as simple as possible, and
- we believe that restricting the scope of attributes to names like
`sanitize_realtime_blocking` is an effective means of doing so.
We also feel that the symmetry between `[[clang::blocking]]` and
`sanitize_realtime_blocking` is easier to follow as a developer.
# Concerns
- I'm aware that the LLVM attribute `sanitize_realtime_unsafe` has been
part of the tree for a few weeks now (introduced here:
https://github.com/llvm/llvm-project/pull/106754). Given that it hasn't
been released in version 20 yet, am I correct in considering this to not
be a breaking change?
Type::isScalableTy and StructType::containsScalableVectorType failed to
detect some cases of structs containing scalable vectors because
containsScalableVectorType did not call back into isScalableTy to check
the element types. Fix this, which requires sharing the same Visited set
in both functions. Also change the external API so that callers are
never required to pass in a Visited set, and normalize the naming to
isScalableTy.
In a variety of places we change the bitwidth of a parameter but don't
update the attributes.
The issue in this case is from the `range` attribute when inlining
`__memset_chk`. `optimizeMemSetChk` will replace an `i32` with an
`i8`, and if the `i32` had a `range` attr assosiated it will cause an
error.
Fixes#112633
This is intended to solve a problem with lowering atomics in
OpenMP and C++ common to AMDGPU and NVPTX.
In OpenCL and CUDA, it is undefined behavior for an atomic instruction
to modify an object in thread private memory. In OpenMP, it is defined.
Correspondingly, the hardware does not handle this correctly. For
AMDGPU,
32-bit atomics work and 64-bit atomics are silently dropped. We
therefore
need to codegen this by inserting a runtime address space check,
performing
the private case without atomics, and fallback to issuing the real
atomic
otherwise. This metadata allows us to avoid this extra check and branch.
Handle this by introducing metadata intended to be applied to atomicrmw,
indicating they cannot access the forbidden address space.
This reverts commit 178fc4779ece31392a2cd01472b0279e50b3a199.
This attribute was not needed now that we are using the lsan style
ScopedDisabler for disabling this sanitizer
See #106736#106125
For more discussion
This patch is part of a set of patches that add an `-fextend-lifetimes`
flag to clang, which extends the lifetimes of local variables and
parameters for improved debuggability. In addition to that flag, the
patch series adds a pragma to selectively disable `-fextend-lifetimes`,
and an `-fextend-this-ptr` flag which functions as `-fextend-lifetimes`
for this pointers only. All changes and tests in these patches were
written by Wolfgang Pieb (@wolfy1961), while Stephen Tozer (@SLTozer)
has handled review and merging. The extend lifetimes flag is intended to
eventually be set on by `-Og`, as discussed in the RFC
here:
https://discourse.llvm.org/t/rfc-redefine-og-o1-and-add-a-new-level-of-og/72850
This patch implements a new intrinsic instruction in LLVM,
`llvm.fake.use` in IR and `FAKE_USE` in MIR, that takes a single operand
and has no effect other than "using" its operand, to ensure that its
operand remains live until after the fake use. This patch does not emit
fake uses anywhere; the next patch in this sequence causes them to be
emitted from the clang frontend, such that for each variable (or this) a
fake.use operand is inserted at the end of that variable's scope, using
that variable's value. This patch covers everything post-frontend, which
is largely just the basic plumbing for a new intrinsic/instruction,
along with a few steps to preserve the fake uses through optimizations
(such as moving them ahead of a tail call or translating them through
SROA).
Co-authored-by: Stephen Tozer <stephen.tozer@sony.com>
This patch is moving out stepvector intrinsic from the experimental
namespace.
This intrinsic exists in LLVM for several years now, and is widely used.
Verify that the arguments of a naked function are not used. They can
only be referenced via registers/stack in inline asm, not as IR values.
Doing so will result in assertion failures in the backend.
There's probably more that we should verify, though I'm not completely
sure what the constraints are (would it be correct to require that naked
functions are exactly an inline asm call + unreachable, or is more
allowed?)
Fixes https://github.com/llvm/llvm-project/issues/104718.
With opaque pointers we can just get the pointer type for the
resolver function by using PointerType::get, making the
GlobalIFunc::getResolverFunctionType function obsolete.
This commit adds LLVM Intrinsics and NVPTX codegen support for
`fence.proxy.tensormap` with lit tests under fence-proxy-tensormap.ll.
Also, added Intrinsics documentation in NVPTXUsage.rst
---------
Co-authored-by: gonzalobg <65027571+gonzalobg@users.noreply.github.com>
The 2^14 limit was completely arbitrary; the generic limit is still
arbitrary, but at least it's the same arbitrary limit as everything
else.
While I'm here, also add a verifier check for the ByValOrByRefSize.
This is the first step in being able to track the total profiled sizes
of allocations successfully marked as cold.
Under a new option -memprof-report-hinted-sizes:
- For unambiguous (non-context-sensitive) allocations, print the
profiled size and the allocation coldness, along with a hash of the
allocation's location (to allow for deduplication across modules or
inline instances).
- For context sensitive allocations, add the size as a 3rd operand on
the MIB metadata. A follow on patch will propagate this through to the
thin link where the sizes will be reported for each context after
cloning.
So far branch protection, sign return address, guarded control stack
attributes are
only emitted as module flags to indicate the functions need to be
generated with
those features.
The problem is in case of an LTO build the module flags are merged with
the `min`
rule which means if one of the module is not build with sign return
address then the features
will be turned off for all functions. Due to the functions take the
branch-protection and
sign-return-address features from the module flags. The
sign-return-address is
function level option therefore it is expected functions from files that
is
compiled with -mbranch-protection=pac-ret to be protected.
The inliner might inline functions with different set of flags as it
doesn't consider
the module flags.
This patch adds the attributes to all functions and drops the checking
of the module flags
for the code generation.
Module flag is still used for generating the ELF markers.
Also drops the "true"/"false" values from the
branch-protection-enforcement,
branch-protection-pauth-lr, guarded-control-stack attributes as presence
of the
attribute means it is on absence means off and no other option.
Releand with test fixes.
So far branch protection, sign return address, guarded control stack
attributes are
only emitted as module flags to indicate the functions need to be
generated with
those features.
The problem is in case of an LTO build the module flags are merged with
the `min`
rule which means if one of the module is not build with sign return
address then the features
will be turned off for all functions. Due to the functions take the
branch-protection and
sign-return-address features from the module flags. The
sign-return-address is
function level option therefore it is expected functions from files that
is
compiled with -mbranch-protection=pac-ret to be protected.
The inliner might inline functions with different set of flags as it
doesn't consider
the module flags.
This patch adds the attributes to all functions and drops the checking
of the module flags
for the code generation.
Module flag is still used for generating the ELF markers.
Also drops the "true"/"false" values from the
branch-protection-enforcement,
branch-protection-pauth-lr, guarded-control-stack attributes as presence
of the
attribute means it is on absence means off and no other option.
Due to the current order of metadata in DISubprgram, `Type` is processed
before `Unit` by the Verifier. This can cause a race and
use of garbage data. Consider the following code:
```
int test(int a[][5])
{
return a[0][2];
}
```
when compiled with clang, the control reaches
`Verifier::visitDISubrange` first with `CurrentSourceLang` still equal
to dwarf::DW_LANG_lo_user (32768). The `Verifier::visitDICompileUnit`
which sets the value of `CurrentSourceLang` is reached later. So
`Verifier::visitDISubrange` ends up using a wrong value of
`CurrentSourceLang`.
This behavior does not effect C like language much but is a problem for
Fortran. There is special processing in `Verifier::visitDISubrange` when
`CurrentSourceLang` is Fortran. With this problem, that special handling
is missed and verifier fails for any code that has Fortran's assumed
size array in a global subroutine.
Various solutions were tried to solve this problem before it was decided that
best course of action is to remove these checks from Verifier.
