Commit Graph

40 Commits

Author SHA1 Message Date
Johannes Doerfert 5eba7846a5 [Attributor] Use checkForAllUses instead of custom use tracking
AAMemoryBehaviorFloating used a custom use tracking mechanism even
though checkForAllUses exists and is already more powerful. Further,
AAMemoryBehaviorFloating uses AANoCapture to guarantee that there are no
aliases and following the uses is sufficient. This is an OK assumption
if checkForAllUses is used but custom tracking is easily out of sync
with AANoCapture and problems follow.
2021-07-20 01:39:33 -05:00
Johannes Doerfert 5fbb51d8d5 [Attributor] Extend the AAValueSimplify compare simplification logic
We first simplify the operands of a compare and then reason on the
simplified versions, e.g., with AANonNull.

This does improve the simplification capabilities but also fixes a
potential problem that has not yet been observed by simplifying the
operands first.
2021-07-20 00:35:14 -05:00
Johannes Doerfert c2281f1565 [Attributor] Introduce AAPointerInfo
This patch introduces AAPointerInfo which tracks the uses of a pointer
and places them in "bins" based on their offset from the base and access
size.

As with other AAs, any pointer can be tracked but it is up to the user
to make sense of the results. The user in this patch is AAValueSimplify
and AAPotentialValues which both utilize AAPointerInfo to determine the
value of a load. For now, this is restricted to loads of allocas and
internal globals. Through the use of AAPointerInfo and the "bins" we can
track struct members separately. The users also know that storing only
zeros (at unknown indices) will result in loading only 0 (from unknown
indices). Other than that, the users are flow and context insensitive
(for now).

To deal with the "bins" more easily, AAPointerInfo provides a
forallInterfearingAccesses that applies a callback on all accesses
that might interfere with a given load or store.

Differential Revision: https://reviews.llvm.org/D104432
2021-07-19 22:48:35 -05:00
Johannes Doerfert c1c1fe9385 [Attributor] Reorganize AAHeapToStack
In order to simplify future extensions, e.g., the merge of
AAHeapToShared in to AAHeapToStack, we reorganize AAHeapToStack and the
state we keep for each malloc-like call. The result is also less
confusing as we only track malloc-like calls, not all calls. Further, we
only perform the updates necessary for a malloc-like to argue it can go
to the stack, e.g., we won't check all uses if we moved on to the
"must-be-freed" argument.

This patch also uses Attributor helps to simplify the allocated size,
alignment, and the potentially freed objects.

Overall, this is mostly a reorganization and only the use of the
optimistic helpers should change (=improve) the capabilities a bit.

Differential Revision: https://reviews.llvm.org/D104993
2021-07-10 16:32:24 -05:00
Johannes Doerfert dbb3a65f5b [Attributor][FIX] Do not replace a value with a non-dominating instruction
We have to be careful when we replace values to not use a non-dominating
instruction. It makes sense that simplification offers those as
"simplified values" but we can't manifest them in the IR without PHI
nodes. In the future we should consider potentially adding those PHI
nodes.
2021-07-10 16:09:30 -05:00
Johannes Doerfert 5ef18e2421 [Attributor] Use AAValueSimplify to simplify returned values
We should use AAValueSimplify for all value simplification, however
there was some leftover logic that predates AAValueSimplify in
AAReturnedValues. This remove the AAReturnedValues part and provides a
replacement by making AAValueSimplifyReturned strong enough to handle
all previously covered cases. Further, this improve
AAValueSimplifyCallSiteReturned to handle returned arguments.

AAReturnedValues is now much easier and the collected returned
values/instructions are now from the associated function only, making it
much more sane. We also do not have the brittle logic anymore that looks
for unresolved calls. Instead, we use AAValueSimplify to handle
recursion.

Useful code has been split into helper functions, e.g., an Attributor
interface to get a simplified value.

Differential Revision: https://reviews.llvm.org/D103860
2021-07-10 15:52:36 -05:00
Nico Weber d3e7491333 Revert Attributor patch series
Broke check-clang, see https://reviews.llvm.org/D102307#2869065
Ran `git revert -n ebbe149a6f08535ede848a531a601ae6591cfbc5..269416d41908bb670f67af689155d5ab8eea689a`
2021-07-10 16:15:55 -04:00
Johannes Doerfert ae08df87df [Attributor][FIX] Do not replace a value with a non-dominating instruction
We have to be careful when we replace values to not use a non-dominating
instruction. It makes sense that simplification offers those as
"simplified values" but we can't manifest them in the IR without PHI
nodes. In the future we should consider potentially adding those PHI
nodes.
2021-07-10 12:32:50 -05:00
Johannes Doerfert 1eb31d6de3 [Attributor] Reorganize AAHeapToStack
In order to simplify future extensions, e.g., the merge of
AAHeapToShared in to AAHeapToStack, we reorganize AAHeapToStack and the
state we keep for each malloc-like call. The result is also less
confusing as we only track malloc-like calls, not all calls. Further, we
only perform the updates necessary for a malloc-like to argue it can go
to the stack, e.g., we won't check all uses if we moved on to the
"must-be-freed" argument.

This patch also uses Attributor helps to simplify the allocated size,
alignment, and the potentially freed objects.

Overall, this is mostly a reorganization and only the use of the
optimistic helpers should change (=improve) the capabilities a bit.

Differential Revision: https://reviews.llvm.org/D104993
2021-07-10 12:32:50 -05:00
Johannes Doerfert 374e573cfc [Attributor] Use AAValueSimplify to simplify returned values
We should use AAValueSimplify for all value simplification, however
there was some leftover logic that predates AAValueSimplify in
AAReturnedValues. This remove the AAReturnedValues part and provides a
replacement by making AAValueSimplifyReturned strong enough to handle
all previously covered cases. Further, this improve
AAValueSimplifyCallSiteReturned to handle returned arguments.

AAReturnedValues is now much easier and the collected returned
values/instructions are now from the associated function only, making it
much more sane. We also do not have the brittle logic anymore that looks
for unresolved calls. Instead, we use AAValueSimplify to handle
recursion.

Useful code has been split into helper functions, e.g., an Attributor
interface to get a simplified value.

Differential Revision: https://reviews.llvm.org/D103860
2021-07-10 12:32:50 -05:00
Johannes Doerfert 9bd2ee0788 [Attriibutor][NFC] Precommit heap-2-stack test case 2021-07-06 22:41:23 -05:00
Joseph Huber 4c9471581f [Attributor] Set floating point loads and stores as nofree in AANoFreeFloating
Summary:
The current implementation of AANoFreeFloating will incorrectly list floating
point loads and stores as may-free. This prevents other attributor instances
like HeapToStack from pushing some allocations to the stack.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D103975
2021-06-09 16:16:37 -04:00
Nicolai Hähnle a888e492f6 [IR] Memory intrinsics are not unconditionally `nosync`
Remove the `nosync` attribute from the memory intrinsic definitions
(i.e. memset, memcpy, memmove).

Like native memory accesses, memory intrinsics can be volatile. This is
indicated by an immarg in the intrinsic call. All else equal, a volatile
memory intrinsic is `sync`, so we cannot annotate the intrinsic functions
themselves as `nosync`. The attributor and function-attr passes know to
take the volatile bit into account.

Since `nosync` is a default attribute, this means we have to stop using
the DefaultAttrIntrinsic tablegen class for memory intrinsics, and
specify all default attributes other than `nosync` explicitly.

Most of the test changes are trivial churn, but one test case
(in nosync.ll) was in fact incorrect before this change.

Differential Revision: https://reviews.llvm.org/D102295
2021-05-21 03:40:59 +02:00
Johannes Doerfert 9c2074dccb [Attributor][NFC] Update tests after D94741
The update_test_checks script can now check for global symbols and is able
to handle them properly when they differ across prefixes, e.g.,
attribute #0 might be different in different runs.

This patch simply updates all the Attributor tests with the new script.

Reviewed By: sstefan1

Differential Revision: https://reviews.llvm.org/D97906
2021-03-11 23:31:39 -06:00
aqjune 5f3c99085d [ValueTracking] Dereferenced pointers are noundef
This is a follow-up of D95238's LangRef update.
This patch updates `programUndefinedIfUndefOrPoison(V)` to return true if
`V` is used by any memory-accessing instruction.
Interestingly, this affected many tests in Attributors, mainly about adding noundefs.
The tests are updated using llvm/utils/update_test_checks.py. I checked that the diffs
are about updating noundefs.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D96642
2021-02-14 22:50:48 +09:00
sstefan1 fbfb1c7909 [IR] Make nosync, nofree and willreturn default for intrinsics.
D70365 allows us to make attributes default. This is a follow up to
actually make nosync, nofree and willreturn default. The approach we
chose, for now, is to opt-in to default attributes to avoid introducing
problems to target specific intrinsics. Intrinsics with default
attributes can be created using `DefaultAttrsIntrinsic` class.
2020-10-20 11:57:19 +02:00
Johannes Doerfert d445b6dfec [Attributor] Cleanup `::initialize` of various AAs
This commit cleans up the ::initialize method of various AAs in the
following ways:
  - If an associated function is required, give up on declarations.
    This was discovered as a real problem when lots of llvm.dbg.XXX
    call sites were assumed `noreturn` until proven otherwise. That
    does not make any sense and caused huge regressions and missed
    deductions.
  - Require more associated declarations for function interface AAs.
  - Use the IRAttribute::initialize to determine if function interface
    AAs can be used in IPO, don't replicate the checks (especially
    isFunctionIPOAmendable) all over the place. Arguably the function
    declaration check should be moved to some central place to.
2020-09-09 01:38:25 -05:00
Shinji Okumura 7a15dfd056 [Attributor] Fix AANoUndef identification
Even though `noundef` IR attribute might be attached to non-void type values, AANoUndef is mistakenly identified for pointer type values only.
This patch fixes that.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D86737
2020-08-30 05:39:25 +09:00
sstefan1 6ce5b74b82 [Attributor][NFC] rerun update_test_checks without --scrub-attributes 2020-08-29 19:34:10 +02:00
Shinji Okumura e21a22a7a8 [Attributor] fix AANoUndef initialization
Currently, `AANoUndefImpl::initialize` mistakenly always indicates optimistic fixpoint for function returned position.
 This is because an associated value is `Function` in the case, and `isGuaranteedNotToBeUndefOrPoison` returns true for Function.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D86361
2020-08-22 05:06:14 +09:00
Shinji Okumura 5e361e2aa4 [Attributor] Deduce noundef attribute
This patch introduces a new abstract attribute `AANoUndef` which corresponds to `noundef` IR attribute and deduce them.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D85184
2020-08-18 18:05:54 +09:00
Johannes Doerfert 8abd69aa9e [Attributor] Bail early if AAMemoryLocation cannot derive anything
Before this change we looked through all memory operations in a function
even if the first was an unknown call that could do anything. This did
cost a lot of time but there is little use to do so. We also avoid
creating AAs for things that we would have looked at in case no other AA
will; that is the reason for the test changes.

Running only the attributor-cgscc pass on a IR version of
`llvm-test-suite/MultiSource/Applications/SPASS/clause.c` reduced the
time we spend in `AAMemoryLocation::update` from 4% total to
0.9% (disclaimer: no accurate measurements).
2020-08-17 23:36:36 -05:00
Arthur Eubanks 4a10029d7e [NewPM][Attributor] Pin tests with -attributor to legacy PM
All these tests already explicitly test against both legacy PM and NPM.

$ sed -i 's/ -attributor / -attributor -enable-new-pm=0 /g' $(rg --path-separator // -l -- -passes=)
$ sed -i 's/ -attributor-cgscc / -attributor-cgscc -enable-new-pm=0 /g' $(rg --path-separator // -l -- -passes=)

Now all tests in Transforms/Attributor/ pass under NPM.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D84813
2020-07-29 09:02:30 -07:00
sstefan1 e3d646c699 [Attributor][NFC] applying update_test_checks with --check-attributes
Summary:
All tests are updated, except wrapper.ll since it is not working nicely
with newly created functions.

Reviewers: jdoerfert, uenoku, baziotis, homerdin

Subscribers: arphaman, jfb, kuter, bbn, okura, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D84130
2020-07-20 08:17:34 +02:00
Johannes Doerfert 43d8d59d6d [Attributor][NFC] Update tests after recent changes
Attributor tests are mostly updated using the auto upgrade scripts but
sometimes we forget. If we do it manually or continue using old check
lines that still match we see unrelated changes down the line. This is
just a cleanup.
2020-07-10 10:39:32 -05:00
Eli Friedman 11aa3707e3 StoreInst should store Align, not MaybeAlign
This is D77454, except for stores.  All the infrastructure work was done
for loads, so the remaining changes necessary are relatively small.

Differential Revision: https://reviews.llvm.org/D79968
2020-05-15 12:26:58 -07:00
Johannes Doerfert 31c03b9223 [Attributor] Use existing helpers to determine IR facts
We now use getPointerDereferenceableBytes to determine `nonnull` and
`dereferenceable` facts from the IR. We also use getPointerAlignment in
AAAlign for the same reason. The latter can interfere with callbacks so
we do restrict it to non-function-pointers for now.
2020-05-10 19:06:10 -05:00
Johannes Doerfert edf0391491 [Attributor][FIX] Record dependences for assumed dead abstract attributes
In a recent patch we introduced a problem with abstract attributes that
were assumed dead at some point. Since `Attributor::updateAA` was
introduced in 95e0d28b71, we did not
remember the dependence on the liveness AA when an abstract attribute
was assumed dead and therefore not updated.

Explicit reproducer added in liveness.ll.

---

Single run of the Attributor module and then CGSCC pass (oldPM)
for SPASS/clause.c (~10k LLVM-IR loc):

Before:
```
calls to allocation functions: 509242 (345483/s)
temporary memory allocations: 98666 (66937/s)
peak heap memory consumption: 18.60MB
peak RSS (including heaptrack overhead): 103.29MB
total memory leaked: 269.10KB
```

After:
```
calls to allocation functions: 529332 (355494/s)
temporary memory allocations: 102107 (68574/s)
peak heap memory consumption: 19.40MB
peak RSS (including heaptrack overhead): 102.79MB
total memory leaked: 269.10KB
```

Difference:
```
calls to allocation functions: 20090 (1339333/s)
temporary memory allocations: 3441 (229400/s)
peak heap memory consumption: 801.45KB
peak RSS (including heaptrack overhead): 0B
total memory leaked: 0B
```
2020-05-07 17:00:50 -05:00
Johannes Doerfert 2f97b8b891 [Attributor][NFC] Proactively ask for `nocapure` on call site arguments
This minimizes test noise later on and is in line with other attributes
we derive proactively.
2020-05-03 21:38:06 -05:00
Johannes Doerfert e2b53a4c05 [Attributor][NFC] Remove obsolete option from tests
Since D76871 it is sufficient to run `opt -atributor` or
`-attributor-cgscc`.
2020-04-21 15:22:10 -05:00
Johannes Doerfert 3ca54f4595 [Attributor] Unify testing (=updates,prefixes,run configurations,...)
When the Attributor was created the test update scripts were not well
suited to deal with the challenges of IR attribute checking. This
partially improved.

Since then we also added three additional configurations that need
testing; in total we now have the following four:
{ TUNIT, CGSCC } x { old pass manager (OPM), new pass manager (NPM) }

Finally, the number of developers and tests grew rapidly (partially due
to the addition of ArgumentPromotion and IPConstantProp tests), which
resulted in tests only being run in some configurations, different
prefixes being used, and different "styles" of checks being used.

Due to the above reasons I believed we needed to take another look at
the test update scripts. While we started to use them, via UTC_ARGS:
--enable/disable, the other problems remained. To improve the testing
situation for *all* configurations, to simplify future updates to the
test, and to help identify subtle effects of future changes, we now use
the test update scripts for (almost) all Attributor tests.

An exhaustive prefix list minimizes the number of check lines and makes
it easy to identify and compare configurations.

Tests have been adjusted in the process but we tried to keep their
intend unchanged.

Reviewed By: sstefan1

Differential Revision: https://reviews.llvm.org/D76588
2020-04-15 19:59:51 -05:00
Florian Hahn 0c22cb0fd7 Temporarily revert "[Attributor] Unify testing (=updates,...)"
This patch reverts the 2 patches below, as on most systems the disabled
tests actually pass and that causes most bots to be red, including
  http://green.lab.llvm.org/green/job/clang-stage1-RA/8541/
  http://green.lab.llvm.org/green/job/clang-stage1-cmake-RA-expensive/15646/
  http://lab.llvm.org:8011/builders/clang-ppc64le-linux-lnt/builds/23690
  http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap/builds/16751

* [Attributor] Disable three tests until the SCC update bug was fixed
  commit 2ae1a76c27.

* [Attributor] Unify testing (=updates,prefixes,run configurations,...)
  2bcf5793e1.
2020-04-09 11:11:50 +01:00
Johannes Doerfert 2bcf5793e1 [Attributor] Unify testing (=updates,prefixes,run configurations,...)
When the Attributor was created the test update scripts were not well
suited to deal with the challenges of IR attribute checking. This
partially improved.

Since then we also added three additional configurations that need
testing; in total we now have the following four:
{ TUNIT, CGSCC } x { old pass manager (OPM), new pass manager (NPM) }

Finally, the number of developers and tests grew rapidly (partially due
to the addition of ArgumentPromotion and IPConstantProp tests), which
resulted in tests only being run in some configurations, different
prefixes being used, and different "styles" of checks being used.

Due to the above reasons I believed we needed to take another look at
the test update scripts. While we started to use them, via UTC_ARGS:
--enable/disable, the other problems remained. To improve the testing
situation for *all* configurations, to simplify future updates to the
test, and to help identify subtle effects of future changes, we now use
the test update scripts for (almost) all Attributor tests.

An exhaustive prefix list minimizes the number of check lines and makes
it easy to identify and compare configurations.

Tests have been adjusted in the process but we tried to keep their
intend unchanged.

Reviewed By: sstefan1

Differential Revision: https://reviews.llvm.org/D76588
2020-04-08 22:52:46 -05:00
Shinji Okumura c80cf48801 [Attributor] AAReachability : use isPotentiallyReachable in isKnownReachable
`isKnownReachable` had only interface (always returns true).
 Changed it to call `isPotentiallyReachable`.
This change enables deductions of other Abstract Attributes depending on
AAReachability to use reachability information obtained from CFG, and it
can make them stronger.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D76210
2020-04-04 19:16:17 -05:00
Johannes Doerfert 9e19693994 [Attributor] Derive better alignment for accessed pointers
Use DL & ABI information for better alignment deduction, e.g., if a type
is accessed and the ABI specifies an alignment requirement for such an
access we can use it. This is based on a patch by @lebedev.ri and
inspired by getBaseAlign in Loads.cpp.

Depends on D76673.

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D76674
2020-04-01 21:49:57 -05:00
Uday Bondhugula c4499e3333 [Attributor] Make attributor aware of aligned_alloc for heap to stack conversion
Make the attributor pass aware of aligned_alloc for converting heap
allocations to stack ones.

Depends on D76971.

Differential Revision: https://reviews.llvm.org/D76974
2020-04-01 23:26:50 +05:30
Hideto Ueno e253cdda35 [MustExecute] Add backward exploration for must-be-executed-context
Summary:
As mentioned in D71974, it is useful for must-be-executed-context to explore CFG backwardly.
This patch is ported from parts of D64975. We use a dominator tree to find the previous context if
a dominator tree is available.

Reviewers: jdoerfert, hfinkel, baziotis, sstefan1

Reviewed By: jdoerfert

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74817
2020-02-20 14:49:30 +09:00
Stefan Stipanovic fff8ec9813 [Attributor] H2S fix.
Summary: Fixing issues that were noticed in D71521

Reviewers: jdoerfert, lebedev.ri, uenoku

Subscribers:

Differential Revision: https://reviews.llvm.org/D71564
2019-12-17 20:41:09 +01:00
Stefan Stipanovic d020e67575 [Attributor][NFC] Add test for sle comparison in h2s. 2019-12-17 20:36:10 +01:00
Hideto Ueno 96552036e3 [Attributor] Copy or port test cases related to Attributor to` Attributor` test folder
Summary:
This patch moves the test cases related to Attributor to `Transforms/Attributor` folder.
We have used `Transforms/FunctionAttrs` as the primary folder for Attributor test but we need to change testing way now.

For the test cases which I think functionattrs doesn't infer anything something like (willreturn, nosync, value-simplify, h2s ..etc), I moved them with the command `git mv`.

For the test cases in which functoinattrs and attributor are tested, I copied the test to the folder and remove the check only used by functoinattrs.

Reviewers: jdoerfert, sstefan1

Reviewed By: jdoerfert

Subscribers: jfb, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70843
2019-12-02 15:36:29 +00:00