Commit Graph

125 Commits

Author SHA1 Message Date
Michael Gottesman d5b701faf1 [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.

llvm-svn: 179973
2013-04-21 02:59:44 +00:00
Michael Gottesman 77aa946321 [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).
llvm-svn: 179972
2013-04-21 01:57:46 +00:00
Michael Gottesman 524052fec1 [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.
llvm-svn: 179971
2013-04-21 01:42:24 +00:00
Michael Gottesman 323964ca9e [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

llvm-svn: 179747
2013-04-18 05:39:45 +00:00
Michael Gottesman a15ab25238 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.
llvm-svn: 179745
2013-04-18 04:34:06 +00:00
Michael Gottesman 31ba23aa56 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.

llvm-svn: 178922
2013-04-05 22:54:32 +00:00
Michael Gottesman 1d8d25777d 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.

llvm-svn: 178921
2013-04-05 22:54:28 +00:00
Michael Gottesman b8c8836594 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.

llvm-svn: 178612
2013-04-03 02:57:24 +00:00
Michael Gottesman 9412830090 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.

llvm-svn: 178382
2013-03-29 22:44:59 +00:00
Michael Gottesman 3b8f877860 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).

llvm-svn: 178369
2013-03-29 21:15:23 +00:00
Michael Gottesman 49f9885a2a 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>.

llvm-svn: 178285
2013-03-28 20:11:30 +00:00
Michael Gottesman 158fdf699e [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>.

llvm-svn: 178284
2013-03-28 20:11:19 +00:00
Michael Gottesman 46ebe53ead 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.

llvm-svn: 178101
2013-03-27 00:09:58 +00:00
Bill Wendling 1ee6d8cef4 Remove testcase. It's failing on some platforms but not others.
llvm-svn: 177956
2013-03-26 01:10:03 +00:00
Bill Wendling d78cfa81be Hmm...not failing...odd
llvm-svn: 177955
2013-03-26 01:08:02 +00:00
Bill Wendling a5a44d4fd6 Temporarily XFAIL this test until Michael can look at it.
llvm-svn: 177953
2013-03-26 00:46:31 +00:00
Michael Gottesman cd4de0f9bb [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.

llvm-svn: 177952
2013-03-26 00:42:09 +00:00
John McCall a237239097 Add an optimizer-side test case for ARC bug <rdar://13195034>, fixed
in the frontend with @clang.arc.use.

llvm-svn: 177928
2013-03-25 22:09:52 +00:00
John McCall 20182ac0c7 Kill every call to @clang.arc.use in the ARC contract phase.
llvm-svn: 177769
2013-03-22 21:38:36 +00:00
Michael Gottesman a8b60a4fda 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.

llvm-svn: 177240
2013-03-17 21:31:12 +00:00
Michael Gottesman 9782183126 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.

llvm-svn: 177232
2013-03-17 08:42:58 +00:00
Bill Wendling a032374ea0 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.

llvm-svn: 175877
2013-02-22 09:09:42 +00:00
Bill Wendling 90bc19cd91 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 }

llvm-svn: 175605
2013-02-20 07:21:42 +00:00
Dmitri Gribenko 44ee2e7a23 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.

llvm-svn: 173163
2013-01-22 14:39:21 +00:00
Michael Gottesman 469a465fa8 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.

llvm-svn: 173126
2013-01-22 04:41:11 +00:00
Michael Gottesman 00dfc68c2d Added test for r172599 which fixes bugzilla://14584,rdar://11744105.
llvm-svn: 172656
2013-01-16 21:07:18 +00:00
Michael Gottesman c99ee6b336 Added bugzilla PR number to test case.
llvm-svn: 172369
2013-01-13 22:17:22 +00:00
Michael Gottesman f15c0bb495 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.

llvm-svn: 172368
2013-01-13 22:12:06 +00:00
Michael Gottesman 556ff61122 Fixed bug in ObjCARC where we were changing a call from objc_autoreleaseRV => objc_autorelease but were not updating the InstructionClass to IC_Autorelease.
llvm-svn: 172288
2013-01-12 01:25:19 +00:00
Michael Gottesman c9656faf1e 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.

llvm-svn: 172287
2013-01-12 01:25:15 +00:00
Dmitri Gribenko 56bf2e1830 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.

llvm-svn: 171250
2012-12-30 02:33:22 +00:00
Dan Gohman 7c84dad80a Detect overflow in the path count computation. rdar://12277446.
llvm-svn: 163739
2012-09-12 20:45:17 +00:00
Dan Gohman df476e5e93 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.

llvm-svn: 163180
2012-09-04 23:16:20 +00:00
Benjamin Kramer 2f47a3fb07 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.

llvm-svn: 162097
2012-08-17 12:28:26 +00:00
Dan Gohman f64ff8ed3a An objc_retain can serve as a may-use for a different pointer.
rdar://11931823.

llvm-svn: 160637
2012-07-23 19:27:31 +00:00
Dan Gohman 5f725cd196 Fix the objc_autoreleasedReturnValue optimization code to locate
the call correctly even in the case where it is an invoke. This
fixes rdar://11714057.

llvm-svn: 159157
2012-06-25 19:47:37 +00:00
Dan Gohman 14862c3141 Fix replacing all the users of objc weak runtime routines
when deleting them. rdar://11434915.

llvm-svn: 157080
2012-05-18 22:17:29 +00:00
Dan Gohman f8b19d09ba Fix the objc_storeStrong recognizer to stop before walking off the
end of a basic block if there's no store.

llvm-svn: 156520
2012-05-09 23:08:33 +00:00
Filipe Cabecinhas 5c43305383 Fixed a typo
llvm-svn: 156471
2012-05-09 14:43:50 +00:00
Dan Gohman 61708d37d6 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.

llvm-svn: 156442
2012-05-08 23:34:08 +00:00
Dan Gohman 26aa827461 Avoid a bug in the path count computation, preventing an infinite
loop repeatedlt making the same change. This is for rdar://11256239.

llvm-svn: 155160
2012-04-19 21:50:46 +00:00
Dan Gohman e1e352af2b 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.

llvm-svn: 154682
2012-04-13 18:28:58 +00:00
Dan Gohman de8d2c446b Use the new Use-aware dominates method to apply the objc runtime
library return value optimization for phi uses. Even when the
phi itself is not dominated, the specific use may be dominated.

llvm-svn: 154647
2012-04-13 01:08:28 +00:00
Dan Gohman 8478d76d64 Don't move objc_autorelease calls past autorelease pool boundaries when
optimizing autorelease calls on phi nodes with null operands.
This fixes rdar://11207070.

llvm-svn: 154642
2012-04-13 00:59:57 +00:00
Dan Gohman cc64bbca81 Fix accidentally inverted logic from r152803, and make the
testcase slightly less trivial. This fixes rdar://11171718.

llvm-svn: 154118
2012-04-05 20:27:21 +00:00
Dan Gohman e3ed2b0699 Don't convert objc_retainAutoreleasedReturnValue to objc_retain if it
is retaining the return value of an invoke that it immediately follows.

llvm-svn: 153344
2012-03-23 18:09:00 +00:00
Dan Gohman 5c70fadc17 It's not possible to insert code immediately after an invoke in the
same basic block, and it's not safe to insert code in the successor
blocks if the edges are critical edges. Splitting those edges is
possible, but undesirable, especially on the unwind side. Instead,
make the bottom-up code motion to consider invokes to be part of
their successor blocks, rather than part of their parent blocks, so
that it doesn't push code past them and onto the edges. This fixes
PR12307.

llvm-svn: 153343
2012-03-23 17:47:54 +00:00
Rafael Espindola f58927855b Short term fix for pr12270 before we change dominates to handle unreachable
code.
While here, reduce indentation.

llvm-svn: 152803
2012-03-15 15:52:59 +00:00
Dan Gohman 532fb8131b When an invoke is marked with metadata indicating its unwind edge
should be ignored by ARC optimization, don't insert new ARC runtime
calls in the unwind destination.

llvm-svn: 152748
2012-03-14 23:05:06 +00:00
Dan Gohman 500b598c5c When identifying exit nodes for the reverse-CFG reverse-post-order
traversal, consider nodes for which the only successors are backedges
which the traversal is ignoring to be exit nodes. This fixes a problem
where the bottom-up traversal was failing to visit split blocks along
split loop backedges. This fixes rdar://10989035.

llvm-svn: 152421
2012-03-09 18:50:52 +00:00
Dan Gohman 0155f30a9c Calls and invokes with the new clang.arc.no_objc_arc_exceptions
metadata may still unwind, but only in ways that the ARC
optimizer doesn't need to consider. This permits more
aggressive optimization.

llvm-svn: 150829
2012-02-17 18:59:53 +00:00
Eli Bendersky 924f9a671d Replace all instances of dg.exp file with lit.local.cfg, since all tests are run with LIT now and now Dejagnu. dg.exp is no longer needed.
Patch reviewed by Daniel Dunbar. It will be followed by additional cleanup patches.

llvm-svn: 150664
2012-02-16 06:28:33 +00:00
Dan Gohman eb6e01533a Just like in regular escape analysis, loads and stores through
(but not of) a block pointer do not cause the block pointer to
escape. This fixes rdar://10803830.

llvm-svn: 150424
2012-02-13 22:57:02 +00:00
Dan Gohman 8ee108bf98 Set the "tail" flag on pattern-matched objc_storeStrong calls.
rdar://10531041.

llvm-svn: 148490
2012-01-19 19:14:36 +00:00
Dan Gohman 82041c2e60 Use llvm.global_ctors to locate global constructors instead
of recognizing them by name.

llvm-svn: 148416
2012-01-18 21:19:38 +00:00
Dan Gohman e7a243fea5 Add a new ObjC ARC optimization pass to eliminate unneeded
autorelease push+pop pairs.

llvm-svn: 148330
2012-01-17 20:52:24 +00:00
Dan Gohman 728db4997a Implement proper ObjC ARC objc_retainBlock "escape" analysis, so that
the optimizer doesn't eliminate objc_retainBlock calls which are needed
for their side effect of copying blocks onto the heap.
This implements rdar://10361249.

llvm-svn: 148076
2012-01-13 00:39:07 +00:00
Dan Gohman bd944b4153 It turns out that clang does use pointer-to-function types to
point to ARC-managed pointers sometimes. This fixes rdar://10551239.

llvm-svn: 146577
2011-12-14 19:10:53 +00:00
Chris Lattner 6a144a2227 Upgrade syntax of tests using volatile instructions to use 'load volatile' instead of 'volatile load', which is archaic.
llvm-svn: 145171
2011-11-27 06:54:59 +00:00
Dan Gohman a7107f992e Teach the ARC optimizer about the !clang.arc.copy_on_escape metadata
tag on objc_retainBlock calls, which indicates that they may be
optimized away. rdar://10211286.

llvm-svn: 142298
2011-10-17 22:53:25 +00:00
Dan Gohman 1736c14b85 Suppress partial retain+release elimination when there's a
possibility that it will span multiple CFG diamonds/triangles which
could have different controlling predicates.  rdar://10282956

llvm-svn: 142222
2011-10-17 18:48:25 +00:00
Dan Gohman 4ac148dcbc When eliminating unnecessary retain+autorelease on return values,
handle the case where the retain is in a different basic block.
rdar://10210274.

llvm-svn: 140815
2011-09-29 22:27:34 +00:00
Dan Gohman 2053a5dd64 Don't eliminate objc_retainBlock calls on stack objects if the
objc_retainBlock call is potentially responsible for copying
the block to the heap to extend its lifetime. rdar://10209613.

llvm-svn: 140814
2011-09-29 22:25:23 +00:00
Dan Gohman d4b5e3a4d9 objc_retainBlock is not NoModRef because it can update forwarding pointers
in memory relevant to the optimizer. rdar://10050579.

llvm-svn: 139708
2011-09-14 18:13:00 +00:00
Bill Wendling e6174a2c85 Update more tests to the new EH scheme.
llvm-svn: 138894
2011-08-31 21:04:11 +00:00
Dan Gohman 56e1cef705 Constant pointers to objects don't need reference counting.
llvm-svn: 138242
2011-08-22 17:29:11 +00:00
Dan Gohman bce94fded8 Make a few tests slightly more strict.
llvm-svn: 138241
2011-08-22 17:27:02 +00:00
Dan Gohman b38940135b Track a retain+release nesting level independently of the
known-incremented level, because the two concepts can be used
to prove the saftey of a retain+release removal in different
ways.

llvm-svn: 138016
2011-08-19 00:26:36 +00:00
Eli Friedman 02e737b08e Move "atomic" and "volatile" designations on instructions after the opcode
of the instruction.

Note that this change affects the existing non-atomic load and store
instructions; the parser now accepts both forms, and the change is noted
in the release notes.

llvm-svn: 137527
2011-08-12 22:50:01 +00:00
Dan Gohman 10a18d55ce Don't convert objc_autoreleaseReturnValue to objc_autorelease if the result
is returned through a bitcast.

llvm-svn: 137402
2011-08-12 00:36:31 +00:00
Dan Gohman 121302772d Don't let arbitrary calls disrupt nested retain+release pairs if
the retains and releases all use the same SSA pointer value.

Also, don't let CFG hazards disrupt nested retain+release pair
optimizations.

llvm-svn: 137399
2011-08-12 00:26:31 +00:00
Dan Gohman b24a1d29cb Tidy up these testcases to look more like real code does.
llvm-svn: 137085
2011-08-09 00:33:11 +00:00
Dan Gohman 6320f52ff4 Move the last uses of RetainFunc etc. over to using getRetainCallee() etc.
so that a declaration for objc_retain is created when needed if it doesn't
already exist. rdar://9825114.

llvm-svn: 135821
2011-07-22 22:29:21 +00:00
Dan Gohman 00fa9634d5 Fix ARCOpt to insert releases on both successors of an invoke rather
than trying to insert them immediately after the invoke.

llvm-svn: 133188
2011-06-16 20:57:14 +00:00
John McCall d935e9c359 The ARC language-specific optimizer. Credit to Dan Gohman.
llvm-svn: 133108
2011-06-15 23:37:01 +00:00