Commit Graph

83 Commits

Author SHA1 Message Date
Michael Gottesman
95a1b3484d [objc-arc] Remove the alias analysis part of r185764.
Upon further reflection, the alias analysis part of r185764 is not a safe
change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185770 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-07 04:18:03 +00:00
Michael Gottesman
0a80c12402 [objc-arc] Teach the ARC optimizer that objc_sync_enter/objc_sync_exit do not modify the ref count of an objc object and additionally are inert for modref purposes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185769 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-07 01:52:55 +00:00
Michael Gottesman
9eb856bc29 [objc-arc] Ensure that the cfg path count does not overflow when we multiply TopDownPathCount/BottomUpPathCount.
rdar://12480535

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183489 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-07 06:16:49 +00:00
Michael Gottesman
7932798384 [objc-arc] KnownSafe does not imply that it is safe to perform code motion across CFG edges since even if it is safe to remove RR pairs, we may still be able to move a retain/release into a loop.
rdar://13949644

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182670 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-24 20:44:05 +00:00
Michael Gottesman
35e88e57ea [objc-arc] Make sure that multiple owners is propogated correctly through the pass via the usage of a global data structure.
rdar://13750319

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182669 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-24 20:44:02 +00:00
Michael Gottesman
acfb3584c5 [objc-arc-opts] In the presense of an alloca unconditionally remove RR pairs if and only if we are both KnownSafeBU/KnownSafeTD rather than just either or.
In the presense of a block being initialized, the frontend will emit the
objc_retain on the original pointer and the release on the pointer loaded from
the alloca. The optimizer will through the provenance analysis realize that the
two are related (albiet different), but since we only require KnownSafe in one
direction, will match the inner retain on the original pointer with the guard
release on the original pointer. This is fixed by ensuring that in the presense
of allocas we only unconditionally remove pointers if both our retain and our
release are KnownSafe (i.e. we are KnownSafe in both directions) since we must
deal with the possibility that the frontend will emit what (to the optimizer)
appears to be unbalanced retain/releases.

An example of the miscompile is:

  %A = alloca
  retain(%x)
  retain(%x) <--- Inner Retain
  store %x, %A
  %y = load %A
  ... DO STUFF ...
  release(%y)
  call void @use(%x)
  release(%x) <--- Guarding Release

getting optimized to:

  %A = alloca
  retain(%x)
  store %x, %A
  %y = load %A
  ... DO STUFF ...
  release(%y)
  call void @use(%x)

rdar://13750319

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181743 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-13 23:49:42 +00:00
Michael Gottesman
f11a6856cc [objc-arc] Apply the RV optimization to retains next to calls in ObjCARCContract instead of ObjCARCOpts.
Turning retains into retainRV calls disrupts the data flow analysis in
ObjCARCOpts. Thus we move it as late as we can by moving it into
ObjCARCContract.

We leave in the conversion from retainRV -> retain in ObjCARCOpt since
it enables the dataflow analysis.

rdar://10813093

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180698 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-29 06:53:53 +00:00
Michael Gottesman
2c2e85536d [objc-arc] Test cleanups.
Mainly adding paranoid checks for the closing brace of a function to
help with FileCheck error readability. Also some other minor changes.

No actual CHECK changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180668 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-27 05:25:54 +00:00
Michael Gottesman
899b2f9d0b [objc-arc] Cleaned up tail-call-invariant-enforcement.ll.
Specifically:

1. Added checks that unwind is being properly added to various instructions.
2. Fixed the declaration/calling of objc_release to have a return type of void.
3. Moved all checks to precede the functions and added checks to ensure that the
checks would only match inside the specific function that we are attempting to
check.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179973 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-21 02:59:44 +00:00
Michael Gottesman
bf9cac7ebb [objc-arc] Check that objc-arc-expand properly handles all strictly forwarding calls and does not touch calls which are not strictly forwarding (i.e. objc_retainBlock).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179972 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-21 01:57:46 +00:00
Michael Gottesman
755aabc04e [objc-arc] Renamed the test file clang-arc-used-intrinsic-removed-if-isolated.ll -> intrinsic-use-isolated.ll to match the other test file intrinsic-use.ll.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179971 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-21 01:42:24 +00:00
Michael Gottesman
0556900b26 [objc-arc] Do not mismatch up retains inside a for loop with releases outside said for loop in the presense of differing provenance caused by escaping blocks.
This occurs due to an alloca representing a separate ownership from the
original pointer. Thus consider the following pseudo-IR:

  objc_retain(%a)
  for (...) {
    objc_retain(%a)
    %block <- %a
    F(%block)
    objc_release(%block)
  }
  objc_release(%a)

From the perspective of the optimizer, the %block is a separate
provenance from the original %a. Thus the optimizer pairs up the inner
retain for %a and the outer release from %a, resulting in segfaults.

This is fixed by noting that the signature of a mismatch of
retain/releases inside the for loop is a Use/CanRelease top down with an
None bottom up (since bottom up the Retain-CanRelease-Use-Release
sequence is completed by the inner objc_retain, but top down due to the
differing provenance from the objc_release said sequence is not
completed). In said case in CheckForCFGHazards, we now clear the state
of %a implying that no pairing will occur.

Additionally a test case is included.

rdar://12969722

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179747 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-18 05:39:45 +00:00
Michael Gottesman
fd4ce16b7a Streamline arc-annotation test (removing some cases which do not add any extra coverage) and set it up to use FileCheck variables to make the test more robust.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179745 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-18 04:34:06 +00:00
Michael Gottesman
e8b3c2e48a An objc_retain can serve as a use for a different pointer.
This is the counterpart to commit r160637, except it performs the action
in the bottomup portion of the data flow analysis.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178922 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-05 22:54:32 +00:00
Michael Gottesman
e7ce2b3f75 Properly model precise lifetime when given an incomplete dataflow sequence.
The normal dataflow sequence in the ARC optimizer consists of the following
states:

    Retain -> CanRelease -> Use -> Release

The optimizer before this patch stored the uses that determine the lifetime of
the retainable object pointer when it bottom up hits a retain or when top down
it hits a release. This is correct for an imprecise lifetime scenario since what
we are trying to do is remove retains/releases while making sure that no
``CanRelease'' (which is usually a call) deallocates the given pointer before we
get to the ``Use'' (since that would cause a segfault).

If we are considering the precise lifetime scenario though, this is not
correct. In such a situation, we *DO* care about the previous sequence, but
additionally, we wish to track the uses resulting from the following incomplete
sequences:

  Retain -> CanRelease -> Release   (TopDown)
  Retain <- Use <- Release          (BottomUp)

*NOTE* This patch looks large but the most of it consists of updating
test cases. Additionally this fix exposed an additional bug. I removed
the test case that expressed said bug and will recommit it with the fix
in a little bit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178921 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-05 22:54:28 +00:00
Michael Gottesman
a67a20c95f Remove an optimization where we were changing an objc_autorelease into an objc_autoreleaseReturnValue.
The semantics of ARC implies that a pointer passed into an objc_autorelease
must live until some point (potentially down the stack) where an
autorelease pool is popped. On the other hand, an
objc_autoreleaseReturnValue just signifies that the object must live
until the end of the given function at least.

Thus objc_autorelease is stronger than objc_autoreleaseReturnValue in
terms of the semantics of ARC* implying that performing the given
strength reduction without any knowledge of how this relates to
the autorelease pool pop that is further up the stack violates the
semantics of ARC.

*Even though objc_autoreleaseReturnValue if you know that no RV
optimization will occur is more computationally expensive.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178612 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-03 02:57:24 +00:00
Michael Gottesman
2030d5f3e9 Updated test0 of retain-not-declared.ll to reflect the fact that objc-arc-expand runs before objc-arc/objc-arc-contract.
Specifically, objc-arc-expand will make sure that the
objc_retainAutoreleasedReturnValue, objc_autoreleaseReturnValue, and ret
will all have %call as an argument.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178382 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-29 22:44:59 +00:00
Michael Gottesman
3e9f3a0389 Add clang.arc.used to ModuleHasARC so ARC always runs if said call is present in a module.
clang.arc.used is an interesting call for ARC since ObjCARCContract
needs to run to remove said intrinsic to avoid a linker error (since the
call does not exist).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178369 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-29 21:15:23 +00:00
Michael Gottesman
3832eff354 Non optimizable objc_retainBlock calls are not forwarding.
Since we handle optimizable objc_retainBlocks through strength reduction
in OptimizableIndividualCalls, we know that all code after that point
will only see non-optimizable objc_retainBlock calls. IsForwarding is
only called by functions after that point, so it is ok to just classify
objc_retainBlock as non-forwarding.

<rdar://problem/13249661>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178285 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-28 20:11:30 +00:00
Michael Gottesman
0d92a3c600 [ObjCARC] Strength reduce objc_retainBlock -> objc_retain if the objc_retainBlock is optimizable.
If an objc_retainBlock has the copy_on_escape metadata attached to it
AND if the block pointer argument only escapes down the stack, we are
allowed to strength reduce the objc_retainBlock to to an objc_retain and
thus optimize it.

Current there is logic in the ARC data flow analysis to handle
this case which is complicated and involved making distinctions in
between objc_retainBlock and objc_retain in certain places and
considering them the same in others.

This patch simplifies said code by:

1. Performing the strength reduction in the initial ARC peephole
analysis (ObjCARCOpts::OptimizeIndividualCalls).

2. Changes the ARC dataflow analysis (which runs after the peephole
analysis) to consider all objc_retainBlock calls to not be optimizable
(since if the call was optimizable, we would have strength reduced it
already).

This patch leaves in the infrastructure in the ARC dataflow analysis to
handle this case, which due to 2 will just be dead code. I am doing this
on purpose to separate the removal of the old code from the testing of
the new code.

<rdar://problem/13249661>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178284 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-28 20:11:19 +00:00
Michael Gottesman
d841d6f71e Added back in the test for arc-annotations.
The test was removed since I had not turned off the test during release
builds. This fails since ARC annotations support  is conditionally
compiled out during release builds. I added the proper requires header
to assuage this issue.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178101 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-27 00:09:58 +00:00
Bill Wendling
bd3148b285 Remove testcase. It's failing on some platforms but not others.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177956 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-26 01:10:03 +00:00
Bill Wendling
15827a8355 Hmm...not failing...odd
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177955 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-26 01:08:02 +00:00
Bill Wendling
7c6f5a5c84 Temporarily XFAIL this test until Michael can look at it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177953 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-26 00:46:31 +00:00
Michael Gottesman
26dbfb6a78 [ObjCARC Annotations] Added support for displaying the state of pointers at the bottom/top of BBs of the ARC dataflow analysis for both bottomup and topdown analyses.
This will allow for verification and analysis of the merge function of
the data flow analyses in the ARC optimizer.

The actual implementation of this feature is by introducing calls to
the functions llvm.arc.annotation.{bottomup,topdown}.{bbstart,bbend}
which are only declared. Each such call takes in a pointer to a global
with the same name as the pointer whose provenance is being tracked and
a pointer whose name is one of our Sequence states and points to a
string that contains the same name.

To ensure that the optimizer does not consider these annotations in any
way, I made it so that the annotations are considered to be of IC_None
type.

A test case is included for this commit and the previous
ObjCARCAnnotation commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177952 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-26 00:42:09 +00:00
John McCall
3800f5748f Add an optimizer-side test case for ARC bug <rdar://13195034>, fixed
in the frontend with @clang.arc.use.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177928 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-25 22:09:52 +00:00
John McCall
1f9c4407c0 Kill every call to @clang.arc.use in the ARC contract phase.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177769 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-22 21:38:36 +00:00
Michael Gottesman
64d667bc07 Reduced dont-infinite-loop-during-block-escape-analysis.ll with bugpoint and moved it to retain-block-escape-analysis.ll.
*NOTE* I verified that the original bug behind
dont-infinite-loop-during-block-escape-analysis.ll occurs when using opt on
retain-block-escape-analysis.ll.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177240 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-17 21:31:12 +00:00
Michael Gottesman
a98729b10e The promised test case for r175939.
This test makes sure that the ObjCARC escape analysis looks at the uses of
instructions which copy the block pointer value by checking all four cases where
that can occur.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177232 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-17 08:42:58 +00:00
Bill Wendling
351b7a10e2 Use references to attribute groups on the call/invoke instructions.
Listing all of the attributes for the callee of a call/invoke instruction is way
too much and makes the IR unreadable. Use references to attributes instead.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175877 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-22 09:09:42 +00:00
Bill Wendling
7ab6c76ad1 Modify the LLVM assembly output so that it uses references to represent function attributes.
This makes the LLVM assembly look better. E.g.:

     define void @foo() #0 { ret void }
     attributes #0 = { nounwind noinline ssp }


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175605 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-20 07:21:42 +00:00
Dmitri Gribenko
91df03b8f2 Tests: rewrite 'opt ... %s' to 'opt ... < %s' so that opt does not emit a ModuleID
This is done to avoid odd test failures, like the one fixed in r171243.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173163 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-22 14:39:21 +00:00
Michael Gottesman
fc8d1dd024 This test is only supposed to test that the objc-arc alias analysis
allows for gvn to perform certain optimizations. Thus the runline should
only contain -objc-arc-aa, not the full -objc-arc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173126 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-22 04:41:11 +00:00
Michael Gottesman
ac47c1bc39 Added test for r172599 which fixes bugzilla://14584,rdar://11744105.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172656 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-16 21:07:18 +00:00
Michael Gottesman
ab67871375 Added bugzilla PR number to test case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172369 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-13 22:17:22 +00:00
Michael Gottesman
6056b85bb5 Fixed an infinite loop in the block escape in analysis in ObjCARC caused by 2x blocks each assigned a value via a phi-node causing each to depend on the other.
A test case is provided as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172368 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-13 22:12:06 +00:00
Michael Gottesman
0e385450fc Fixed bug in ObjCARC where we were changing a call from objc_autoreleaseRV => objc_autorelease but were not updating the InstructionClass to IC_Autorelease.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172288 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-12 01:25:19 +00:00
Michael Gottesman
e8c161a924 Fixed a bug where we were tail calling objc_autorelease causing an object to not be placed into an autorelease pool.
The reason that this occurs is that tail calling objc_autorelease eventually
tail calls -[NSObject autorelease] which supports fast autorelease. This can
cause us to violate the semantic gaurantees of __autoreleasing variables that
assignment to an __autoreleasing variables always yields an object that is
placed into the innermost autorelease pool.

The fix included in this patch works by:

1. In the peephole optimization function OptimizeIndividualFunctions, always
remove tail call from objc_autorelease.
2. Whenever we convert to/from an objc_autorelease, set/unset the tail call
keyword as appropriate.

*NOTE* I also handled the case where objc_autorelease is converted in
OptimizeReturns to an autoreleaseRV which still violates the ARC semantics. I
will be removing that in a later patch and I wanted to make sure that the tree
is in a consistent state vis-a-vis ARC always.

Additionally some test cases are provided and all tests that have tail call marked
objc_autorelease keywords have been modified so that tail call has been removed.

*NOTE* One test fails due to a separate bug that I am going to commit soon. Thus
I marked the check line TMP: instead of CHECK: so make check does not fail.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172287 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-12 01:25:15 +00:00
Dmitri Gribenko
a6542923b8 Tests: rewrite 'opt ... %s' to 'opt ... < %s' so that opt does not emit a ModuleID
This is done to avoid odd test failures, like the one fixed in r171243.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171250 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-30 02:33:22 +00:00
Dan Gohman
0d1bc5f916 Detect overflow in the path count computation. rdar://12277446.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163739 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-12 20:45:17 +00:00
Dan Gohman
230768bd13 Make provenance checking conservative in cases when
pointers-to-strong-pointers may be in play. These can lead to retains and
releases happening in unstructured ways, foiling the optimizer. This fixes
rdar://12150909.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163180 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-04 23:16:20 +00:00
Benjamin Kramer
4e81d40545 Fix broken check lines.
I really need to find a way to automate this, but I can't come up with a regex
that has no false positives while handling tricky cases like custom check
prefixes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162097 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-17 12:28:26 +00:00
Dan Gohman
c72d3be389 An objc_retain can serve as a may-use for a different pointer.
rdar://11931823.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160637 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-23 19:27:31 +00:00
Dan Gohman
58fb3401fa Fix the objc_autoreleasedReturnValue optimization code to locate
the call correctly even in the case where it is an invoke. This
fixes rdar://11714057.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159157 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-25 19:47:37 +00:00
Dan Gohman
ce5d8b0d03 Fix replacing all the users of objc weak runtime routines
when deleting them. rdar://11434915.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157080 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-18 22:17:29 +00:00
Dan Gohman
95b8cf1f11 Fix the objc_storeStrong recognizer to stop before walking off the
end of a basic block if there's no store.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156520 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-09 23:08:33 +00:00
Filipe Cabecinhas
7305295538 Fixed a typo
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156471 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-09 14:43:50 +00:00
Dan Gohman
4670dace66 Fix objc_storeStrong pattern matching to catch a potential use of the
old value after the store but before it is released.
This fixes rdar:/11116986.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156442 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-08 23:34:08 +00:00
Dan Gohman
8b74e5afda Avoid a bug in the path count computation, preventing an infinite
loop repeatedlt making the same change. This is for rdar://11256239.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155160 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-19 21:50:46 +00:00
Dan Gohman
4423477548 Consider ObjC runtime calls objc_storeWeak and others which make a copy of
their argument as "escape" points for objc_retainBlock optimization.
This fixes rdar://11229925.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154682 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-13 18:28:58 +00:00