I noticed another instance of the issue where references to aliases were
being replaced with aliasees, this time in InstCombine. In the instance that
I saw it turned out to be only a QoI issue (a symbol ended up being missing
from the symbol table due to the last reference to the alias being removed,
preventing HWASAN from symbolizing a global reference), but it could easily
have manifested as incorrect behaviour.
Since this is the third such issue encountered (previously: D65118, D65314)
it seems to be time to address this common error/QoI issue once and for all
and make the strip* family of functions not look through aliases.
Includes a test for the specific issue that I saw, but no doubt there are
other similar bugs fixed here.
As with D65118 this has been tested to make sure that the optimization isn't
load bearing. I built Clang, Chromium for Linux, Android and Windows as well
as the test-suite and there were no size regressions.
Differential Revision: https://reviews.llvm.org/D66606
llvm-svn: 369697
Summary: In D65402, I want to get DerefState from AADereferenceable but it was not allowed. This patch moves DerefState definition into Attributor.h and makes AADerefenceable inherit StateWrapper.
Reviewers: jdoerfert, sstefan1
Reviewed By: jdoerfert
Subscribers: hiraditya, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66585
llvm-svn: 369653
For an internal function, if all its call sites are dead, the body of the function is considered dead.
Reviewers: jdoerfert, uenoku
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D66155
llvm-svn: 369470
Summary:
StringMap is used for storing call target to frequency map for AutoFDO. However the iterating order of StringMap is non-deterministic, which leads to non-determinism in AutoFDO profile output. Now new API getSortedCallTargets and SortCallTargets are added for deterministic ordering and output.
Roundtrip test for text profile and binary profile is added.
Reviewers: wmi, davidxl, danielcdh
Subscribers: hiraditya, mgrang, llvm-commits, twoh
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66191
llvm-svn: 369440
Summary:
When the line format is wrong, we may end up accessing out of bound
memory. eg: the test with invalide line will cause assert.
Assertion `idx < size()' failed
The fix is to report fatal when we found mismatched line format.
Reviewers: qcolombet, volkan
Reviewed By: qcolombet
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66444
llvm-svn: 369389
Before, we create the set of abstract attributes initially and then
dealt with the fact hat a lookup could fail, e.g., return a nullptr.
This patch will ensure we always return a valid object from a lookup,
allowing us not only to remove the nullptr checks but also to grow the
set of abstract attributes "in-flight" on-demand.
One can now start from those that have the best chance of improving
performance without the need to specify all they might depend on.
While this introduces some boilerplate, the usage of attributes is much
easier and cleaner now.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66276
llvm-svn: 369331
Summary:
This is analogous to D66128 but for AADereferenceable. We have the logic
concentrated in the floating value updateImpl and we use the combiner
helper classes for arguments and return values.
The regressions will go away with "on-demand" attribute creation.
Improvements are already visible in the existing tests.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66272
llvm-svn: 369329
Summary:
What D66126 did for AAAlign, this patch does for AANonNull. Agian, the
logic becomes more concise and localized. Again, returned poiners are
not annotated properly but that will not be an issue if this lands with
the "on-demand" generation of attributes. First improvements due to the
genericValueTraversal are already visible.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66128
llvm-svn: 369328
The clamp operator should not take the known of the given state as the
known is potentially based on assumed information. This also adds TODOs
to guide improvements.
llvm-svn: 369327
This reverts commit cedd0d9a6e.
Re-apply the original commit but make sure the variables are initialized
(even if they are not used) so UBSan is not complaining.
llvm-svn: 369294
By partially resolving returned calls we did not record that they were
not fully resolved which caused odd behavior down the line. We could
also end up with some, but not all, returned values of the callee in the
returned values map of the caller, another odd behavior we want to
avoid.
llvm-svn: 369160
As a preparation to "on-demand" abstract attribute generation we need
implementations for all attributes (as they can be queried and then
created on-demand where we now fail to find one).
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66129
llvm-svn: 369155
Summary:
This is the first commit aiming to structure the attribute deduction.
The base idea is that we have default propagation patterns as listed
below on top of which we can add specific, e.g., context sensitive,
logic.
Deduction patterns used in this patch:
- argument states are determined from call site argument states,
see AAAlignArgument and AAArgumentFromCallSiteArguments.
- call site argument states are determined as if they were floating
values, see AAAlignCallSiteArgument and AAAlignFloating.
- floating value states are determined by traversing the def-use chain
and combining the states determined for the leaves, see
AAAlignFloating and genericValueTraversal.
- call site return states are determined from function return states,
see AAAlignCallSiteReturned and AACallSiteReturnedFromReturned.
- function return states are determined from returned value states,
see AAAlignReturned and AAReturnedFromReturnedValues.
Through this strategy all logic for alignment is concentrated in the
AAAlignFloating::updateImpl method.
Note: This commit works on its own but is part of a larger change that
involves "on-demand" creation of abstract attributes that will
participate in the fixpoint iteration. Without this part, we sometimes
do not have an AAAlign abstract attribute to query, loosing information
we determined before. All tests have appropriate FIXMEs and the
information will be recovered once we added all parts.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66126
llvm-svn: 369144
Until we have call site specific liveness and/or value information there
is no need to do call site specific deduction. Though, we need the
symbols in follow up patches that make Attributor::getAAFor return a
reference.
llvm-svn: 369143
Summary:
This patch should not change the behavior except that the added
initialize methods might indicate an optimistic fixpoint earlier. The
code movement is done to keep the attribute definitions in a single
block where it makes sense. No functional changes intended there.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66258
llvm-svn: 369142
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.
llvm-svn: 369013
Summary:
Instead of constantly keeping track of the nonnull status with the
dereferenceable information we can simply query the nonnull attribute
whenever we need the information (debug + manifest).
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66113
llvm-svn: 368924
Summary:
As one of the first attributes, and one of the complex ones,
AAReturnedValues was not using liveness but we filtered the result after
the fact. This change adds liveness usage during the creation. The
algorithm is also improved and shorter.
The new algorithm will collect returned values over time using the
generic facilities that work with liveness already, e.g.,
genericValueTraversal which does not look at dead PHI node predecessors.
A test to show how this leads to better results is included.
Note: Unresolved calls and resolved calls are now tracked explicitly.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66120
llvm-svn: 368922
Summary:
If the associated context instruction is assumed dead we do not need to
update or manifest the state.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66116
llvm-svn: 368921
Summary:
The next attempt to clean up the Attributor interface before we grow it
further.
Before, we used a combination of two values (associated + anchor) and an
argument number (or -1) to determine a location. This was very fragile.
The new system uses exclusively IR positions and we restrict the
generation of IR positions to special constructor methods that verify
internal constraints we have. This will catch misuse early.
The auto-conversion, e.g., in getAAFor, is now performed through the
SubsumingPositionIterator. This iterator takes an IR position and allows
to visit all IR positions that "subsume" the given one, e.g., function
attributes "subsume" argument attributes of that function. For a
detailed breakdown see the class comment of SubsumingPositionIterator.
This patch also introduces the IRPosition::getAttrs() to extract IR
attributes at a certain position. The method knows how to look up in
different positions that are equivalent, e.g., the argument position for
call site arguments. We also introduce three new positions kinds such
that we have all IR positions where attributes can be placed and one for
"floating" values.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65977
llvm-svn: 368919
Summary:
This commit fixed a race condition from multi-threaded thinLTO backends that causes non-deterministic memory corruption for a data structure used only by AutoFDO with compact binary profile.
GUIDToFuncNameMap, a static data member of type DenseMap in FunctionSamples is used as a per-module mapping from function name MD5 to name string when input AutoFDO profile is in compact binary format. However with ThinLTO, we can have parallel backends modifying and accessing the class static map concurrently. The fix is to make GUIDToFuncNameMap a member of SampleProfileLoader instead of a file static data.
Reviewers: wmi, davidxl, danielcdh
Subscribers: mehdi_amini, inglorion, hiraditya, dexonsmith, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65848
llvm-svn: 368596
The default behavior of Clang's indirect function call checker will replace
the address of each CFI-checked function in the output file's symbol table
with the address of a jump table entry which will pass CFI checks. We refer
to this as making the jump table `canonical`. This property allows code that
was not compiled with ``-fsanitize=cfi-icall`` to take a CFI-valid address
of a function, but it comes with a couple of caveats that are especially
relevant for users of cross-DSO CFI:
- There is a performance and code size overhead associated with each
exported function, because each such function must have an associated
jump table entry, which must be emitted even in the common case where the
function is never address-taken anywhere in the program, and must be used
even for direct calls between DSOs, in addition to the PLT overhead.
- There is no good way to take a CFI-valid address of a function written in
assembly or a language not supported by Clang. The reason is that the code
generator would need to insert a jump table in order to form a CFI-valid
address for assembly functions, but there is no way in general for the
code generator to determine the language of the function. This may be
possible with LTO in the intra-DSO case, but in the cross-DSO case the only
information available is the function declaration. One possible solution
is to add a C wrapper for each assembly function, but these wrappers can
present a significant maintenance burden for heavy users of assembly in
addition to adding runtime overhead.
For these reasons, we provide the option of making the jump table non-canonical
with the flag ``-fno-sanitize-cfi-canonical-jump-tables``. When the jump
table is made non-canonical, symbol table entries point directly to the
function body. Any instances of a function's address being taken in C will
be replaced with a jump table address.
This scheme does have its own caveats, however. It does end up breaking
function address equality more aggressively than the default behavior,
especially in cross-DSO mode which normally preserves function address
equality entirely.
Furthermore, it is occasionally necessary for code not compiled with
``-fsanitize=cfi-icall`` to take a function address that is valid
for CFI. For example, this is necessary when a function's address
is taken by assembly code and then called by CFI-checking C code. The
``__attribute__((cfi_jump_table_canonical))`` attribute may be used to make
the jump table entry of a specific function canonical so that the external
code will end up taking a address for the function that will pass CFI checks.
Fixes PR41972.
Differential Revision: https://reviews.llvm.org/D65629
llvm-svn: 368495
Summary:
The ever growing switch required Attribute::AttrKind values but they
might not be available for all abstract attributes we deduce. With the
new method we track statistics at the abstract attribute level. The
provided macros simplify the usage and make the messages uniform.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65732
llvm-svn: 368227
Summary:
The wrapper reduces boilerplate code and also provide a nice way to
determine the state type used by an abstract attributes statically via
AAType::StateType.
This was already discussed as part of the review of D65711.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65786
llvm-svn: 368224
If we know everything is live there is no need to query for liveness.
Indicating a pessimistic fixpoint will cause the state to be "invalid"
which will cause the Attributor to not return the AAIsDead on request,
which will prevent us from querying isAssumedDead().
llvm-svn: 368223
Summary:
So far, whenever one wants to look at returned values, one had to deal
with the AAReturnedValues and potentially with the AAIsDead attribute.
In the same spirit as other checkForAllXXX methods, we add this
functionality now to the Attributor. By adopting the use sites we got
better results when return instructions were dead.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65733
llvm-svn: 368222
Commit r368064 was necessary after r367953 (D65712) broke the module
build. That happened, apparently, because the template class IRAttribute
defined in the header had a virtual method defined in the corresponding
source file (IRAttribute::manifest). To unbreak the situation this patch
introduces a helper function IRAttributeManifest::manifestAttrs which
is used to implement IRAttribute::manifest in the header. The deifnition
of the helper function is still in the source file.
Patch by jdoerfert (Johannes Doerfert)
Differential Revision: https://reviews.llvm.org/D65821
llvm-svn: 368076
Summary:
Similar to `Attributor::checkForAllCallSites`, we now provide such
functionality for instructions of a certain opcode through
`Attributor::checkForAllInstructions` and the convenient wrapper
`Attributor::checkForAllCallLikeInstructions`. This cleans up code,
avoids duplication, and simplifies the usage of liveness information.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65731
llvm-svn: 367961
Summary:
Certain properties, e.g., an AttrKind, are not shared among all abstract
attributes. This patch extracts the functionality into a helper struct.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65712
llvm-svn: 367953
To remove boilerplate, mostly passing through values to the
AbstractAttriubute base class, we extract the state into an IRPosition
helper. There is no function change intended but the IRPosition struct
will provide more functionality down the line.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65711
llvm-svn: 367952
Summary:
The new scheme is similar to the pass manager and dyn_cast scheme where
we identify classes by the address of a static member. This is better
than the old scheme in which we had to "invent" new Attributor enums if
there was no corresponding one.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65710
llvm-svn: 367951
Summary:
Instead of storing the reference to the InformationCache we now pass it
whenever it might be needed.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65709
llvm-svn: 367950
A function is "no-return" if we never reach a return instruction, either
because there are none or the ones that exist are dead.
Test have been adjusted:
- either noreturn was added, or
- noreturn was avoided by modifying the code.
The new noreturn_{sync,async} test make sure we do handle invoke
instructions with a noreturn (and potentially nowunwind) callee
correctly, even in the presence of potential asynchronous exceptions.
llvm-svn: 367948
When we remove instructions cached references could still be live. This
patch avoids removing invoke instructions that are replaced by calls and
instead keeps them around but in a dead block.
llvm-svn: 367933
Similar to other places where we transform invokes to calls we need to
be careful if the handler (=personality) can catch asynchronous
exceptions as they are not modeled as part of nounwind.
This is tested with D59978.
llvm-svn: 367931
Summary:
This contains various fixes:
- Explicitly determine and return the next noreturn instruction.
- If an invoke calls a noreturn function which is not nounwind we
keep the unwind destination live. This also means we require an
invoke. Though we can still add the unreachable to the normal
destination block.
- Check if the return instructions are dead after we look for calls
to avoid triggering an optimistic fixpoint in the presence of
assumed liveness information.
- Make the interface work with "const" pointers.
- Some simplifications
While additional tests are included, full coverage is achieved only with
D59978.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65701
llvm-svn: 367791
When a fixpoint is indicated the change status is known due to the
fixpoint kind. This simplifies a common code pattern by making the
connection explicit.
llvm-svn: 367790
Summary:
If the DerefBytesState (and thereby the DerefState) is invalid, we
reached a fixpoint for the whole DerefState as we will not
manifest/provide information then.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65586
llvm-svn: 367789
Modifying other AbstractAttributes to use Liveness AA and skip dead instructions.
Reviewers: jdoerfert, uenoku
Subscribers: hiraditya, llvm-commits
Differential revision: https://reviews.llvm.org/D65243
llvm-svn: 367725
This patch adds support to the WholeProgramDevirt pass to perform
index-based WPD, which is invoked from ThinLTO during the thin link.
The ThinLTO backend (WPD import phase) behaves the same regardless of
whether the WPD decisions were made with the index-based or (the
existing) IR-based analysis.
Depends on D54815.
Reviewers: pcc
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, arphaman, dang, llvm-commits
Differential Revision: https://reviews.llvm.org/D55153
llvm-svn: 367679
User of AAReturnedValues need to know if HasOverdefinedReturnedCalls
changed from false to true as it will impact the result of the return
value traversal (calls are not ignored anymore).
This will be tested with the tests in D59978.
llvm-svn: 367581
Summary:
While there is always a `Value::replaceAllUsesWith()`,
sometimes the replacement needs to be conditional.
I have only cleaned a few cases where `replaceUsesWithIf()`
could be used, to both add test coverage,
and show that it is actually useful.
Reviewers: jdoerfert, spatel, RKSimon, craig.topper
Reviewed By: jdoerfert
Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, aheejin, george.burgess.iv, asbirlea, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65528
llvm-svn: 367548
Globals that are associated with globals with type metadata need to appear
in the merged module because they will reference the global's section directly.
Differential Revision: https://reviews.llvm.org/D65312
llvm-svn: 367242
Summary:
Deduce dereferenceable attribute in Attributor.
These will be added in a later patch.
* dereferenceable(_or_null)_globally (D61652)
* Deduction based on load instruction (similar to D64258)
Reviewers: jdoerfert, sstefan1
Reviewed By: jdoerfert
Subscribers: hiraditya, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64876
llvm-svn: 366788
Summary: Adds a binding to the internalize pass that allows the caller to pass a function pointer that acts as the visibility-preservation predicate. Previously, one could only pass an unsigned value (not LLVMBool?) that directed the pass to consider "main" or not.
Reviewers: whitequark, deadalnix, harlanhaskins
Reviewed By: whitequark, harlanhaskins
Subscribers: kren1, hiraditya, llvm-commits, harlanhaskins
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62456
llvm-svn: 366777
[Attributor] Liveness analysis.
Liveness analysis abstract attribute used to indicate which BasicBlocks are dead and can therefore be ignored.
Right now we are only looking at noreturn calls.
Reviewers: jdoerfert, uenoku
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D64162
llvm-svn: 366769
[Attributor] Liveness analysis.
Liveness analysis abstract attribute used to indicate which BasicBlocks are dead and can therefore be ignored.
Right now we are only looking at noreturn calls.
Reviewers: jdoerfert, uenoku
Subscribers: hiraditya, llvm-commits
Differential revision: https://reviews.llvm.org/D64162
llvm-svn: 366753
Liveness analysis abstract attribute used to indicate which BasicBlocks are dead and can therefore be ignored.
Right now we are only looking at noreturn calls.
Reviewers: jdoerfert, uenoku
Subscribers: hiraditya, llvm-commits
Differential revision: https://reviews.llvm.org/D64162
llvm-svn: 366736
Porting function return value attribute noalias to attributor.
This will be followed with a patch for callsite and function argumets.
Reviewers: jdoerfert
Subscribers: lebedev.ri, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D63067
llvm-svn: 366728
The bytes inserted before an overaligned global need to be padded according
to the alignment set on the original global in order for the initializer
to meet the global's alignment requirements. The previous implementation
that padded to the pointer width happened to be correct for vtables on most
platforms but may do the wrong thing if the vtable has a larger alignment.
This issue is visible with a prototype implementation of HWASAN for globals,
which will overalign all globals including vtables to 16 bytes.
There is also no padding requirement for the bytes inserted after the global
because they are never read from nor are they significant for alignment
purposes, so stop inserting padding there.
Differential Revision: https://reviews.llvm.org/D65031
llvm-svn: 366725
We were previously ignoring alignment entirely when combining globals
together in this pass. There are two main things that we need to do here:
add additional padding before each global to meet the alignment requirements,
and set the combined global's alignment to the maximum of all of the original
globals' alignments.
Since we now need to calculate layout as we go anyway, use the calculated
layout to produce GlobalLayout instead of using StructLayout.
Differential Revision: https://reviews.llvm.org/D65033
llvm-svn: 366722
Summary:
Deduce the "willreturn" attribute for functions.
For now, intrinsics are not willreturn. More annotation will be done in another patch.
Reviewers: jdoerfert
Subscribers: jvesely, nhaehnle, nicholas, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63046
llvm-svn: 366335
Add "memtag" sanitizer that detects and mitigates stack memory issues
using armv8.5 Memory Tagging Extension.
It is similar in principle to HWASan, which is a software implementation
of the same idea, but there are enough differencies to warrant a new
sanitizer type IMHO. It is also expected to have very different
performance properties.
The new sanitizer does not have a runtime library (it may grow one
later, along with a "debugging" mode). Similar to SafeStack and
StackProtector, the instrumentation pass (in a follow up change) will be
inserted in all cases, but will only affect functions marked with the
new sanitize_memtag attribute.
Reviewers: pcc, hctim, vitalybuka, ostannard
Subscribers: srhines, mehdi_amini, javed.absar, kristof.beyls, hiraditya, cryptoad, steven_wu, dexonsmith, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D64169
llvm-svn: 366123
There are scenarios where mutually recursive functions may cause the SCC
to contain both read only and write only functions. This removes an
assertion when adding read attributes which caused a crash with a the
provided test case, and instead just doesn't add the attributes.
Patch by Luke Lau <luke.lau@intel.com>
Differential Revision: https://reviews.llvm.org/D60761
llvm-svn: 366090
Attributor::getAAFor will now only return AbstractAttributes with a
valid AbstractState. This simplifies call sites as they only need to
check if the returned pointer is non-null. It also reduces the potential
for accidental misuse.
llvm-svn: 365983
Some function in the Attributor framework are unnecessarily
marked virtual. This patch removes virtual keyword
Reviewers: jdoerfert
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D64637
llvm-svn: 365925
Introduce and deduce "nosync" function attribute to indicate that a function
does not synchronize with another thread in a way that other thread might free memory.
Reviewers: jdoerfert, jfb, nhaehnle, arsenm
Subscribers: wdng, hfinkel, nhaenhle, mehdi_amini, steven_wu,
dexonsmith, arsenm, uenoku, hiraditya, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D62766
llvm-svn: 365830
This makes the functions in Loads.h require a type to be specified
independently of the pointer Value so that when pointers have no structure
other than address-space, it can still do its job.
Most callers had an obvious memory operation handy to provide this type, but a
SROA and ArgumentPromotion were doing more complicated analysis. They get
updated to merge the properties of the various instructions they were
considering.
llvm-svn: 365468
Deduce the "returned" argument attribute by collecting all potentially
returned values.
Not only the unique return value, if any, can be used by subsequent
attributes but also the set of all potentially returned values as well
as the mapping from returned values to return instructions that they
originate from (see AAReturnedValues::checkForallReturnedValues).
Change in statistics (-stats) for LLVM-TS + Spec2006, totaling ~19% more "returned" arguments.
ADDED: attributor NumAttributesManifested n/a -> 637
ADDED: attributor NumAttributesValidFixpoint n/a -> 25545
ADDED: attributor NumFnArgumentReturned n/a -> 637
ADDED: attributor NumFnKnownReturns n/a -> 25545
ADDED: attributor NumFnUniqueReturned n/a -> 14118
CHANGED: deadargelim NumRetValsEliminated 470 -> 449 ( -4.468%)
REMOVED: functionattrs NumReturned 535 -> n/a
CHANGED: indvars NumElimIdentity 138 -> 164 ( +18.841%)
Reviewers: homerdin, hfinkel, fedor.sergeev, sanjoy, spatel, nlopes, nicholas, reames, efriedma, chandlerc
Subscribers: hiraditya, bollu, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D59919
llvm-svn: 365407
This patch adds a function attribute, nofree, to indicate that a function does
not, directly or indirectly, call a memory-deallocation function (e.g., free,
C++'s operator delete).
Reviewers: jdoerfert
Differential Revision: https://reviews.llvm.org/D49165
llvm-svn: 365336
Peter Collingbourne