As discussed in [0], this diff adds the `skipprofile` attribute to
prevent the function from being profiled while allowing profiled
functions to be inlined into it. The `noprofile` attribute remains
unchanged.
The `noprofile` attribute is used for functions where it is
dangerous to add instrumentation to while the `skipprofile` attribute is
used to reduce code size or performance overhead.
[0] https://discourse.llvm.org/t/why-does-the-noprofile-attribute-restrict-inlining/64108
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D130807
Turning on opaque pointers has uncovered an issue with WPD where we currently pattern match away `assume(type.test)` in WPD so that a later LTT doesn't resolve the type test to undef and introduce an `assume(false)`. The pattern matching can fail in cases where we transform two `assume(type.test)`s into `assume(phi(type.test.1, type.test.2))`.
Currently we create `assume(type.test)` for all virtual calls that might be devirtualized. This is to support `-Wl,--lto-whole-program-visibility`.
To prevent this, all virtual calls that may not be in the same LTO module instead use a new `llvm.public.type.test` intrinsic in place of the `llvm.type.test`. Then when we know if `-Wl,--lto-whole-program-visibility` is passed or not, we can either replace all `llvm.public.type.test` with `llvm.type.test`, or replace all `llvm.public.type.test` with `true`. This prevents WPD from trying to pattern match away `assume(type.test)` for public virtual calls when failing the pattern matching will result in miscompiles.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D128955
Following some recent discussions, this changes the representation
of callbrs in IR. The current blockaddress arguments are replaced
with `!` label constraints that refer directly to callbr indirect
destinations:
; Before:
%res = callbr i8* asm "", "=r,r,i"(i8* %x, i8* blockaddress(@test8, %foo))
to label %asm.fallthrough [label %foo]
; After:
%res = callbr i8* asm "", "=r,r,!i"(i8* %x)
to label %asm.fallthrough [label %foo]
The benefit of this is that we can easily update the successors of
a callbr, without having to worry about also updating blockaddress
references. This should allow us to remove some limitations:
* Allow unrolling/peeling/rotation of callbr, or any other
clone-based optimizations
(https://github.com/llvm/llvm-project/issues/41834)
* Allow duplicate successors
(https://github.com/llvm/llvm-project/issues/45248)
This is just the IR representation change though, I will follow up
with patches to remove limtations in various transformation passes
that are no longer needed.
Differential Revision: https://reviews.llvm.org/D129288
For MTE globals, we should have clang emit the attribute for all GV's
that it creates, and then use that in the upcoming AArch64 global
tagging IR pass. We need a positive attribute for this sanitizer (rather
than implicit sanitization of all globals) because it needs to interact
with other parts of LLVM, including:
1. Suppressing certain global optimisations (like merging),
2. Emitting extra directives by the ASM writer, and
3. Putting extra information in the symbol table entries.
While this does technically make the LLVM IR / bitcode format
non-backwards-compatible, nobody should have used this attribute yet,
because it's a no-op.
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D128950
(Reapply after revert in e9ce1a588030d8d4004f5d7e443afe46245e9a92 due to
Fuchsia test failures. Removed changes in lib/ExecutionEngine/ other
than error categories, to be checked in more detail and reapplied
separately.)
Bulk remove many of the more trivial uses of ManagedStatic in the llvm
directory, either by defining a new getter function or, in many cases,
moving the static variable directly into the only function that uses it.
Differential Revision: https://reviews.llvm.org/D129120
Bulk remove many of the more trivial uses of ManagedStatic in the llvm
directory, either by defining a new getter function or, in many cases,
moving the static variable directly into the only function that uses it.
Differential Revision: https://reviews.llvm.org/D129120
This patch adds the support for `fmax` and `fmin` operations in `atomicrmw`
instruction. For now (at least in this patch), the instruction will be expanded
to CAS loop. There are already a couple of targets supporting the feature. I'll
create another patch(es) to enable them accordingly.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D127041
D128820 stopped creating div/rem constant expressions by default;
this patch removes support for them entirely.
The getUDiv(), getExactUDiv(), getSDiv(), getExactSDiv(), getURem()
and getSRem() on ConstantExpr are removed, and ConstantExpr::get()
now only accepts binary operators for which
ConstantExpr::isSupportedBinOp() returns true. Uses of these methods
may be replaced either by corresponding IRBuilder methods, or
ConstantFoldBinaryOpOperands (if a constant result is required).
On the C API side, LLVMConstUDiv, LLVMConstExactUDiv, LLVMConstSDiv,
LLVMConstExactSDiv, LLVMConstURem and LLVMConstSRem are removed and
corresponding LLVMBuild methods should be used.
Importantly, this also means that constant expressions can no longer
trap! This patch still keeps the canTrap() method to minimize diff --
I plan to drop it in a separate NFC patch.
Differential Revision: https://reviews.llvm.org/D129148
Restore the autoupgrade from bitcast to ptrtoint+inttoptr, which
was lost as part of D127729.
This fixes the backwards compatibility issue noted in:
https://reviews.llvm.org/D127729#inline-1236519
This implements an autoupgrade from constant expressions to
instructions, which is needed for
https://discourse.llvm.org/t/rfc-remove-most-constant-expressions/63179.
The basic approach is that constant expressions (CST_CODE_CE_*
records) now initially only create a BitcodeConstant value that
holds opcode, flags and operands IDs. Then, when the value actually
gets used, it can be converted either into a constant expression
(if that expression type is still supported) or into a sequence of
instructions. As currently all expressions are still supported,
-expand-constant-exprs is added for testing purposes, to force
expansion.
PHI nodes require special handling, because the constant expression
needs to be evaluated on the incoming edge. We do this by putting
it into a temporary block and then wiring it up appropriately
afterwards (for non-critical edges, we could also move the
instructions into the predecessor).
This also removes the need for the forward referenced constants
machinery, as the BitcodeConstants only hold value IDs. At the
point where the value is actually materialized, no forward
references are needed anymore.
Differential Revision: https://reviews.llvm.org/D127729
Plan is the migrate the global variable metadata for sanitizers, that's
currently carried around generally in the 'llvm.asan.globals' section,
onto the global variable itself.
This patch adds the attribute and plumbs it through the LLVM IR and
bitcode formats, but is a no-op other than that so far.
Reviewed By: vitalybuka, kstoimenov
Differential Revision: https://reviews.llvm.org/D126100
I chose to encode the allockind information in a string constant because
otherwise we would get a bit of an explosion of keywords to deal with
the possible permutations of allocation function types.
I'm not sure that CodeGen.h is the correct place for this enum, but it
seemed to kind of match the UWTableKind enum so I put it in the same
place. Constructive suggestions on a better location most certainly
encouraged.
Differential Revision: https://reviews.llvm.org/D123088
In certain use-cases, these can be emitted by old compilers, but the
operand is now always required. These are only used for optimizations,
so it's safe to drop them if they happen to have the now-invalid format.
The semantically-required call is already a separate instruction.
Differential Revision: https://reviews.llvm.org/D123811
This continues the push away from hard-coded knowledge about functions
towards attributes. We'll use this to annotate free(), realloc() and
cousins and obviate the hard-coded list of free functions.
Differential Revision: https://reviews.llvm.org/D123083
IRLinker builds a work list of functions to materialize, then moves them
from a source module to a destination module one at a time.
This is a problem for blockaddress Constants, since they need not refer
to the function they are used in; IPSCCP is quite good at sinking these
constants deep into other functions when passed as arguments.
This would lead to curious errors during LTO:
ld.lld: error: Never resolved function from blockaddress ...
based on the ordering of function definitions in IR.
The problem was that IRLinker would basically do:
for function f in worklist:
materialize f
splice f from source module to destination module
in one pass, with Functions being lazily added to the running worklist.
This confuses BitcodeReader, which cannot disambiguate whether a
blockaddress is referring to a function which has not yet been parsed
("materialized") or is simply empty because its body was spliced out.
This causes BitcodeReader to insert Functions into its BasicBlockFwdRefs
list incorrectly, as it will never re-materialize an already
materialized (but spliced out) function.
Because of the possibility that blockaddress Constants may appear in
Functions other than the ones they reference, this patch adds a new
bitcode function code FUNC_CODE_BLOCKADDR_USERS that is a simple list of
Functions that contain BlockAddress Constants that refer back to this
Function, rather then the Function they are scoped in. We then
materialize those functions when materializing `f` from the example loop
above. This might over-materialize Functions should the user of
BitcodeReader ultimately decide not to link those Functions, but we can
at least now we can avoid this ordering related issue with blockaddresses.
Fixes: https://github.com/llvm/llvm-project/issues/52787
Fixes: https://github.com/ClangBuiltLinux/linux/issues/1215
Reviewed By: dexonsmith
Differential Revision: https://reviews.llvm.org/D120781
This allows both explicitly enabling and explicitly disabling
opaque pointers, in anticipation of the default switching at some
point.
This also slightly changes the rules by allowing calls if either
the opaque pointer mode has not yet been set (explicitly or
implicitly) or if the value remains unchanged.
This allows us to more easily test opaque pointers e.g. in the case of
ThinLTO where we only have to pass -opaque-pointers to the frontend.
Reviewed By: #opaque-pointers, nikic
Differential Revision: https://reviews.llvm.org/D122048
Includes verifier changes checking the elementtype, clang codegen
changes to emit the elementtype, and ISel changes using the elementtype.
Basically the same as D120527.
Reviewed By: #opaque-pointers, nikic
Differential Revision: https://reviews.llvm.org/D121847
Includes verifier changes checking the elementtype, clang codegen
changes to emit the elementtype, and ISel changes using the elementtype.
Reviewed By: #opaque-pointers, nikic
Differential Revision: https://reviews.llvm.org/D120527
We should not be using APIs here that try to fetch the attribute
from both the call attributes and the function attributes. Otherwise
we'll try to upgrade a non-existent sret attribute on the call using
the attribute on the function.
Since D101045, allocas are no longer required to be part of the
default alloca address space. There may be allocas in multiple
different address spaces. However, the bitcode reader would
simply assume the default alloca address space, resulting in
either an error or incorrect IR.
Add an optional record for allocas which encodes the address
space.
As these errors are detected after the instruction has already been
created (but before it has been inserted into the function), we
also need to delete it.
This will let us start moving away from hard-coded attributes in
MemoryBuiltins.cpp and put the knowledge about various attribute
functions in the compilers that emit those calls where it probably
belongs.
Differential Revision: https://reviews.llvm.org/D117921
This completes the propagation of type IDs through bitcode reading,
and switches remaining uses of getPointerElementType() to use
contained type IDs.
The main new thing here is that sometimes we need to create a type
ID for a type that was not explicitly encoded in bitcode (or we
don't know its ID at the current point). For such types we create a
"virtual" type ID, which is cached based on the type and the
contained type IDs. Luckily, we generally only need zero or one
contained type IDs, and in the one case where we need two, we can
get away with not including it in the cache key.
With this change, we pass the entirety of llvm-test-suite at O3
with opaque pointers.
Differential Revision: https://reviews.llvm.org/D120471
Currently adding attribute no_sanitize("bounds") isn't disabling
-fsanitize=local-bounds (also enabled in -fsanitize=bounds). The Clang
frontend handles fsanitize=array-bounds which can already be disabled by
no_sanitize("bounds"). However, instrumentation added by the
BoundsChecking pass in the middle-end cannot be disabled by the
attribute.
The fix is very similar to D102772 that added the ability to selectively
disable sanitizer pass on certain functions.
In this patch, if no_sanitize("bounds") is provided, an additional
function attribute (NoSanitizeBounds) is attached to IR to let the
BoundsChecking pass know we want to disable local-bounds checking. In
order to support this feature, the IR is extended (similar to D102772)
to make Clang able to preserve the information and let BoundsChecking
pass know bounds checking is disabled for certain function.
Reviewed By: melver
Differential Revision: https://reviews.llvm.org/D119816
This is the next step towards supporting bitcode auto upgrade with
opaque pointers. The ValueList now stores the Value* together with
its associated type ID, which allows inspecting the original pointer
element type of arbitrary values.
This is a largely mechanical change threading the type ID through
various places. I've left TODOTypeID placeholders in a number of
places where determining the type ID is either non-trivial or
requires allocating a new type ID not present in the original
bitcode. For this reason, the new type IDs are also not used for
anything yet (apart from propagation). They will get used once the
TODOs are resolved.
Differential Revision: https://reviews.llvm.org/D119821
This is step two of supporting autoupgrade of old bitcode to opaque
pointers. Rather than tracking the element type ID of pointers in
particular, track all type IDs that a type contains. This allows us
to recover the element type in more complex situations, e.g. when
we need to determine the pointer element type of a vector element
or function type parameter.
Differential Revision: https://reviews.llvm.org/D119339
