If the ObjectSizeOffsetEvaluator fails to fold the object size call, then it may
litter some unused instructions in the function. When done repeatably in
InstCombine, this results in an infinite loop. Fix this by tracking the set of
instructions that were inserted, then removing them on failure.
rdar://49172227
Differential revision: https://reviews.llvm.org/D60298
llvm-svn: 358146
This is meant to be used with clang's __builtin_dynamic_object_size.
When 'true' is passed to this parameter, the intrinsic has the
potential to be folded into instructions that will be evaluated
at run time. When 'false', the objectsize intrinsic behaviour is
unchanged.
rdar://32212419
Differential revision: https://reviews.llvm.org/D56761
llvm-svn: 352664
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Summary:
Correct to use set like behaviour of AllocType. Should check for
subset, not precise value.
Reviewers: theraven
Reviewed By: theraven
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D50959
llvm-svn: 340807
In non-zero address spaces, we were reporting that an object at `null`
always occupies zero bytes. This is incorrect in many cases, so just
return `unknown` in those cases for now.
Differential Revision: https://reviews.llvm.org/D48860
llvm-svn: 336611
Summary: Previous patch does not care if a value is changed between calloc and strlen. This needs to be removed from InstCombine and maybe moved to DSE later after some rework.
Reviewers: efriedma
Reviewed By: efriedma
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47218
llvm-svn: 333022
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.
In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.
Differential Revision: https://reviews.llvm.org/D43624
llvm-svn: 332240
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46290
llvm-svn: 331272
Summary:
Clang's __builtin_operator_new/delete was recently taught about the aligned allocation overloads (r328134). This patch makes LLVM aware of them as well.
This allows the compiler to perform certain optimizations including eliding new/delete calls.
Reviewers: rsmith, majnemer, dblaikie, vsk, bkramer
Reviewed By: bkramer
Subscribers: ckennelly, llvm-commits
Differential Revision: https://reviews.llvm.org/D44769
llvm-svn: 329218
Summary:
Clang's __builtin_operator_new/delete was recently taught about the aligned allocation overloads (r328134). This patch makes LLVM aware of them as well.
This allows the compiler to perform certain optimizations including eliding new/delete calls.
Reviewers: rsmith, majnemer, dblaikie, vsk, bkramer
Reviewed By: bkramer
Subscribers: ckennelly, llvm-commits
Differential Revision: https://reviews.llvm.org/D44769
llvm-svn: 329215
Remove #include of Transforms/Scalar.h from Transform/Utils to fix layering.
Transforms depends on Transforms/Utils, not the other way around. So
remove the header and the "createStripGCRelocatesPass" function
declaration (& definition) that is unused and motivated this dependency.
Move Transforms/Utils/Local.h into Analysis because it's used by
Analysis/MemoryBuiltins.cpp.
llvm-svn: 328165
This is usually not a problem because this code's main purpose is
eliminating unused new/delete pairs. We got deletes of nullptr or
nobuiltin deletes of builtin new wrong though.
llvm-svn: 325630
Summary:
Solves PR33689.
If the pointer size is less than the size of the type used for the array
size in an alloca (the <ty> type below) then we could trigger the assert in
the PR. In that example we have pointer size i16 and <ty> is i32.
<result> = alloca [inalloca] <type> [, <ty> <NumElements>] [, align <alignment>]
Handle the situation by allowing truncation as well as zero extension in
ObjectSizeOffsetVisitor::visitAllocaInst().
Also, we now detect overflow in visitAllocaInst(), similar to how it was
already done in visitCallSite().
Reviewers: craig.topper, rnk, george.burgess.iv
Reviewed By: george.burgess.iv
Subscribers: davide, llvm-commits
Differential Revision: https://reviews.llvm.org/D35003
llvm-svn: 307754
BasicAA wants to know if a function is either a malloc or calloc like function. Currently we have to check both separately. This means both calls check if its an intrinsic, query TLI, check the nobuiltin attribute, scan the AllocationFnData, etc.
This patch adds a isMallocOrCallocLikeFn so we can go through all of the checks once per call.
This also changes the one other location I saw that called both together.
Differential Revision: https://reviews.llvm.org/D32188
llvm-svn: 300608
This avoids the confusing 'CS.paramHasAttr(ArgNo + 1, Foo)' pattern.
Previously we were testing return value attributes with index 0, so I
introduced hasReturnAttr() for that use case.
llvm-svn: 300367
This adds a parameter to @llvm.objectsize that makes it return
conservative values if it's given null.
This fixes PR23277.
Differential Revision: https://reviews.llvm.org/D28494
llvm-svn: 298430
Summary:
This class is a list of AttributeSetNodes corresponding the function
prototype of a call or function declaration. This class used to be
called ParamAttrListPtr, then AttrListPtr, then AttributeSet. It is
typically accessed by parameter and return value index, so
"AttributeList" seems like a more intuitive name.
Rename AttributeSetImpl to AttributeListImpl to follow suit.
It's useful to rename this class so that we can rename AttributeSetNode
to AttributeSet later. AttributeSet is the set of attributes that apply
to a single function, argument, or return value.
Reviewers: sanjoy, javed.absar, chandlerc, pete
Reviewed By: pete
Subscribers: pete, jholewinski, arsenm, dschuff, mehdi_amini, jfb, nhaehnle, sbc100, void, llvm-commits
Differential Revision: https://reviews.llvm.org/D31102
llvm-svn: 298393
Summary:
The LibFunc::Func enum holds enumerators named for libc functions.
Unfortunately, there are real situations, including libc implementations, where
function names are actually macros (musl uses "#define fopen64 fopen", for
example; any other transitively visible macro would have similar effects).
Strictly speaking, a conforming C++ Standard Library should provide any such
macros as functions instead (via <cstdio>). However, there are some "library"
functions which are not part of the standard, and thus not subject to this
rule (fopen64, for example). So, in order to be both portable and consistent,
the enum should not use the bare function names.
The old enum naming used a namespace LibFunc and an enum Func, with bare
enumerators. This patch changes LibFunc to be an enum with enumerators prefixed
with "LibFFunc_". (Unfortunately, a scoped enum is not sufficient to override
macros.)
There are additional changes required in clang.
Reviewers: rsmith
Subscribers: mehdi_amini, mzolotukhin, nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D28476
llvm-svn: 292848
We currently ignore the `allocsize` attribute on functions calls with
the `nobuiltin` attribute when trying to lower `@llvm.objectsize`. We
shouldn't care about `nobuiltin` here: `allocsize` is explicitly added
by the user, not inferred based on a function's symbol.
llvm-svn: 290588
This also makes us no longer check for `allocsize` on intrinsic calls.
This shouldn't matter, since intrinsics should provide the information
we get from `allocsize` on their own.
llvm-svn: 290585
This patch fixes some ASAN unittest failures on FreeBSD. See the
cfe-commits email thread for r290169 for more on those.
According to the LangRef, the allocsize attribute only tells us about
the number of bytes that exist at the memory location pointed to by the
return value of a function. It does not necessarily mean that the
function will only ever allocate. So, we need to be very careful about
treating functions with allocsize as general allocation functions. This
patch makes us fully conservative in this regard, though I suspect that
we have room to be a bit more aggressive if we want.
This has a FIXME that can be fixed by a relatively straightforward
refactor; I just wanted to keep this patch minimal. If this sticks, I'll
come back and fix it in a few days.
llvm-svn: 290397
We're currently doing nearly the same thing for @llvm.objectsize in
three different places: two of them are missing checks for overflow,
and one of them could subtly break if InstCombine gets much smarter
about removing alloc sites. Seems like a good idea to not do that.
llvm-svn: 290214
This patch changes LLVM_CONSTEXPR variable declarations to const
variable declarations, since LLVM_CONSTEXPR expands to nothing if the
current compiler doesn't support constexpr. In all of the changed
cases, it looks like the code intended the variable to be const instead
of sometimes-constexpr sometimes-not.
llvm-svn: 279696
This patch fixes calculating of builtin_object_size if it depends on a
condition. Before this patch compiler did not know how to calculate the
object size when it finds a condition that cannot be eliminated.
This patch enables calculating of builtin_object_size even in case when
condition cannot be eliminated by choosing minimum or maximum value as a
result from condition. Choosing minimum or maximum value from condition
is based on the second argument of __builtin_object_size function.
Patch by Strahinja Petrovic.
Differential Revision: http://reviews.llvm.org/D18438
llvm-svn: 266193
`allocsize` is a function attribute that allows users to request that
LLVM treat arbitrary functions as allocation functions.
This patch makes LLVM accept the `allocsize` attribute, and makes
`@llvm.objectsize` recognize said attribute.
The review for this was split into two patches for ease of reviewing:
D18974 and D14933. As promised on the revisions, I'm landing both
patches as a single commit.
Differential Revision: http://reviews.llvm.org/D14933
llvm-svn: 266032
Summary:
Fixes PR26774.
If you're aware of the issue, feel free to skip the "Motivation"
section and jump directly to "This patch".
Motivation:
I define "refinement" as discarding behaviors from a program that the
optimizer has license to discard. So transforming:
```
void f(unsigned x) {
unsigned t = 5 / x;
(void)t;
}
```
to
```
void f(unsigned x) { }
```
is refinement, since the behavior went from "if x == 0 then undefined
else nothing" to "nothing" (the optimizer has license to discard
undefined behavior).
Refinement is a fundamental aspect of many mid-level optimizations done
by LLVM. For instance, transforming `x == (x + 1)` to `false` also
involves refinement since the expression's value went from "if x is
`undef` then { `true` or `false` } else { `false` }" to "`false`" (by
definition, the optimizer has license to fold `undef` to any non-`undef`
value).
Unfortunately, refinement implies that the optimizer cannot assume
that the implementation of a function it can see has all of the
behavior an unoptimized or a differently optimized version of the same
function can have. This is a problem for functions with comdat
linkage, where a function can be replaced by an unoptimized or a
differently optimized version of the same source level function.
For instance, FunctionAttrs cannot assume a comdat function is
actually `readnone` even if it does not have any loads or stores in
it; since there may have been loads and stores in the "original
function" that were refined out in the currently visible variant, and
at the link step the linker may in fact choose an implementation with
a load or a store. As an example, consider a function that does two
atomic loads from the same memory location, and writes to memory only
if the two values are not equal. The optimizer is allowed to refine
this function by first CSE'ing the two loads, and the folding the
comparision to always report that the two values are equal. Such a
refined variant will look like it is `readonly`. However, the
unoptimized version of the function can still write to memory (since
the two loads //can// result in different values), and selecting the
unoptimized version at link time will retroactively invalidate
transforms we may have done under the assumption that the function
does not write to memory.
Note: this is not just a problem with atomics or with linking
differently optimized object files. See PR26774 for more realistic
examples that involved neither.
This patch:
This change introduces a new set of linkage types, predicated as
`GlobalValue::mayBeDerefined` that returns true if the linkage type
allows a function to be replaced by a differently optimized variant at
link time. It then changes a set of IPO passes to bail out if they see
such a function.
Reviewers: chandlerc, hfinkel, dexonsmith, joker.eph, rnk
Subscribers: mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D18634
llvm-svn: 265762
Summary:
`hasNoAliasAttr` is buggy: it checks to see if the called function has
a `noalias` attribute, which is incorrect since functions are not even
allowed to have the `noalias` attribute. The comment on its only
caller, `llvm::isNoAliasFn`, makes it pretty clear that the intention
to do the `noalias` check on the return value, and not the callee.
Unfortunately I couldn't find a way to test this upstream -- fixing
this does not change the observable behavior of any of the passes that
use this. This is not very surprising, since `noalias` does not tell
anything about the contents of the allocated memory (so, e.g., you
still cannot fold loads). I'll be happy to be proven wrong though.
Reviewers: chandlerc, reames
Subscribers: mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D17037
llvm-svn: 260298
This patch removes the isOperatorNewLike predicate since it was only being used to establish a non-null return value and we have attributes specifically for that purpose with generic handling. To keep approximate the same behaviour for existing frontends, I added the various operator new like (i.e. instances of operator new) to InferFunctionAttrs. It's not really clear to me why this isn't handled in Clang, but I didn't want to break existing code and any subtle assumptions it might have.
Once this patch is in, I'm going to start separating the isAllocLike family of predicates. These appear to be being used for a mixture of things which should be more clearly separated and documented. Today, they're being used to indicate (at least) aliasing facts, CSE-ability, and default values from an allocation site.
Differential Revision: http://reviews.llvm.org/D15820
llvm-svn: 256787
The compiler can take advantage of the allocation/deallocation
function's properties. We knew how to do this for Itanium but had no
support for MSVC-style functions.
llvm-svn: 254656
Remove implicit ilist iterator conversions from LLVMAnalysis.
I came across something really scary in `llvm::isKnownNotFullPoison()`
which relied on `Instruction::getNextNode()` being completely broken
(not surprising, but scary nevertheless). This function is documented
(and coded to) return `nullptr` when it gets to the sentinel, but with
an `ilist_half_node` as a sentinel, the sentinel check looks into some
other memory and we don't recognize we've hit the end.
Rooting out these scary cases is the reason I'm removing the implicit
conversions before doing anything else with `ilist`; I'm not at all
surprised that clients rely on badness.
I found another scary case -- this time, not relying on badness, just
bad (but I guess getting lucky so far) -- in
`ObjectSizeOffsetEvaluator::compute_()`. Here, we save out the
insertion point, do some things, and then restore it. Previously, we
let the iterator auto-convert to `Instruction*`, and then set it back
using the `Instruction*` version:
Instruction *PrevInsertPoint = Builder.GetInsertPoint();
/* Logic that may change insert point */
if (PrevInsertPoint)
Builder.SetInsertPoint(PrevInsertPoint);
The check for `PrevInsertPoint` doesn't protect correctly against bad
accesses. If the insertion point has been set to the end of a basic
block (i.e., `SetInsertPoint(SomeBB)`), then `GetInsertPoint()` returns
an iterator pointing at the list sentinel. The version of
`SetInsertPoint()` that's getting called will then call
`PrevInsertPoint->getParent()`, which explodes horribly. The only
reason this hasn't blown up is that it's fairly unlikely the builder is
adding to the end of the block; usually, we're adding instructions
somewhere before the terminator.
llvm-svn: 249925
Summary:
Now that the DataLayout is a mandatory part of the module, let's start
cleaning the codebase. This patch is a first attempt at doing that.
This patch is not exactly NFC as for instance some places were passing
a nullptr instead of the DataLayout, possibly just because there was a
default value on the DataLayout argument to many functions in the API.
Even though it is not purely NFC, there is no change in the
validation.
I turned as many pointer to DataLayout to references, this helped
figuring out all the places where a nullptr could come up.
I had initially a local version of this patch broken into over 30
independant, commits but some later commit were cleaning the API and
touching part of the code modified in the previous commits, so it
seemed cleaner without the intermediate state.
Test Plan:
Reviewers: echristo
Subscribers: llvm-commits
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 231740
While the term "Target" is in the name, it doesn't really have to do
with the LLVM Target library -- this isn't an abstraction which LLVM
targets generally need to implement or extend. It has much more to do
with modeling the various runtime libraries on different OSes and with
different runtime environments. The "target" in this sense is the more
general sense of a target of cross compilation.
This is in preparation for porting this analysis to the new pass
manager.
No functionality changed, and updates inbound for Clang and Polly.
llvm-svn: 226078
it's defined in the current module. Clang generates this situation for the
C++14 sized deallocation functions, because it generates a weak definition in
case one isn't provided by the C++ runtime library.
llvm-svn: 226069
This is to be consistent with StringSet and ultimately with the standard
library's associative container insert function.
This lead to updating SmallSet::insert to return pair<iterator, bool>,
and then to update SmallPtrSet::insert to return pair<iterator, bool>,
and then to update all the existing users of those functions...
llvm-svn: 222334
C++14 adds new builtin signatures for 'operator delete'. This change allows
new/delete pairs to be removed in C++14 onwards, as they were in C++11 and
before.
llvm-svn: 219014
Erik Pilkington