Commit Graph

376 Commits

Author SHA1 Message Date
Nick Lewycky 7d0f110cb3 It's not safe to blindly remove invoke instructions. This happens when we
encounter an invoke of an allocation function. This should fix the dragonegg
bootstrap. Testcase to follow, later.

llvm-svn: 160757
2012-07-25 21:19:40 +00:00
Nick Lewycky 38be931223 Don't delete one more instruction than we're allowed to. This should fix the
Darwin bootstrap. Testcase exists but isn't fully reduced, I expect to commit
the testcase this evening.

llvm-svn: 160693
2012-07-24 21:33:00 +00:00
Nick Lewycky faa9c3b035 Teach globalopt to not nuke all stores to globals. Keep them around of they
might be deliberate "one time" leaks, so that leak checkers can find them.
This is a reapply of r160602 with the fix that this time I'm committing the
code I thought I was committing last time; the I->eraseFromParent() goes
*after* the break out of the loop.

llvm-svn: 160664
2012-07-24 07:21:08 +00:00
Nick Lewycky 9669c198ba Revert r160602.
llvm-svn: 160603
2012-07-21 09:03:15 +00:00
Nick Lewycky 72b83e5eaa Teach globalopt to play nice with leak checkers. This is a reapplication of
r160529 that was subsequently reverted. The fix was to not call
GV->eraseFromParent() right before the caller does the same. The existing
testcases already caught this bug if run under valgrind.

llvm-svn: 160602
2012-07-21 08:29:45 +00:00
Nick Lewycky 7707e23429 Revert r160529 due to crashes.
llvm-svn: 160532
2012-07-19 23:59:21 +00:00
Nick Lewycky 0fa6a28141 Don't wipe out global variables that are probably storing pointers to heap
memory. This makes clang play nice with leak checkers.

llvm-svn: 160529
2012-07-19 22:35:28 +00:00
Duncan Sands e8ce94fcd7 GlobalOpt forgot to handle bitcast when analyzing globals. Found by inspection.
llvm-svn: 159546
2012-07-02 18:55:39 +00:00
Matt Beaumont-Gay a58862310c Revert r159136 due to PR13124.
Original commit message:

If a constant or a function has linkonce_odr linkage and unnamed_addr, mark it
hidden. Being linkonce_odr guarantees that it is available in every dso that
needs it. Being a constant/function with unnamed_addr guarantees that the
copies don't have to be merged.

llvm-svn: 159272
2012-06-27 17:10:33 +00:00
Rafael Espindola 540c3d23df If a constant or a function has linkonce_odr linkage and unnamed_addr, mark it
hidden. Being linkonce_odr guarantees that it is available in every dso that
needs it. Being a constant/function with unnamed_addr guarantees that the
copies don't have to be merged.

llvm-svn: 159136
2012-06-25 14:30:31 +00:00
Nick Lewycky b74ae9c5b2 Tab to spaces. No functionality change.
llvm-svn: 159104
2012-06-24 04:07:14 +00:00
Hans Wennborg cbe34b4cc9 Extend the IL for selecting TLS models (PR9788)
This allows the user/front-end to specify a model that is better
than what LLVM would choose by default. For example, a variable
might be declared as

  @x = thread_local(initialexec) global i32 42

if it will not be used in a shared library that is dlopen'ed.

If the specified model isn't supported by the target, or if LLVM can
make a better choice, a different model may be used.

llvm-svn: 159077
2012-06-23 11:37:03 +00:00
Nuno Lopes 0b60ebbf79 fix whitespace in my last commit.
sorry for the churn :S  enough for today; going to sleep.

llvm-svn: 158953
2012-06-22 00:29:58 +00:00
Nuno Lopes 9792d68381 remove extractMallocCallFromBitCast, since it was tailor maded for its sole user. Update GlobalOpt accordingly.
llvm-svn: 158952
2012-06-22 00:25:01 +00:00
Rafael Espindola 1821c6c3b0 Some optimizations done by globalopt are safe only for internal linkage, not
linkonce linkage. For example, it is not valid to add unnamed_addr.

This also fixes a crash in g++.dg/opt/static5.C.

llvm-svn: 158528
2012-06-15 18:00:24 +00:00
Rafael Espindola def1b09be2 Implement the isSafeToDiscardIfUnused predicate and use it in globalopt and
globaldce. Globaldce was already removing linkonce globals, but globalopt was
not.

llvm-svn: 158476
2012-06-14 22:48:13 +00:00
Jay Foad ca0c499609 Teach Function::hasAddressTaken that BlockAddress doesn't really take
the address of a function.

llvm-svn: 156703
2012-05-12 08:30:16 +00:00
Benjamin Kramer aa9e4a5e59 GlobalOpt: If we have an inbounds GEP from a ConstantAggregateZero global that we just determined to be constant, replace all loads from it with a zero value.
llvm-svn: 153576
2012-03-28 14:50:09 +00:00
Dan Gohman eab06fa3c9 Teach globalopt how to evaluate an invoke with a non-void return type.
llvm-svn: 152634
2012-03-13 18:01:37 +00:00
Stepan Dyatkovskiy 5b648afb4d Taken into account Duncan's comments for r149481 dated by 2nd Feb 2012:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20120130/136146.html

Implemented CaseIterator and it solves almost all described issues: we don't need to mix operand/case/successor indexing anymore. Base iterator class is implemented as a template since it may be initialized either from "const SwitchInst*" or from "SwitchInst*".

ConstCaseIt is just a read-only iterator.
CaseIt is read-write iterator; it allows to change case successor and case value.

Usage of iterator allows totally remove resolveXXXX methods. All indexing convertions done automatically inside the iterator's getters.

Main way of iterator usage looks like this:
SwitchInst *SI = ... // intialize it somehow

for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd(); i != e; ++i) {
  BasicBlock *BB = i.getCaseSuccessor();
  ConstantInt *V = i.getCaseValue();
  // Do something.
}

If you want to convert case number to TerminatorInst successor index, just use getSuccessorIndex iterator's method.
If you want initialize iterator from TerminatorInst successor index, use CaseIt::fromSuccessorIndex(...) method.

There are also related changes in llvm-clients: klee and clang.

llvm-svn: 152297
2012-03-08 07:06:20 +00:00
Benjamin Kramer 93887631d9 Plog a memleak in GlobalOpt.
Found by valgrind.

llvm-svn: 151525
2012-02-27 12:48:24 +00:00
Duncan Sands 4730cb9c7c GCC fails to understand that NextBB is always initialized if EvaluateBlock
returns 'true' and emits a warning.  Help it out.

llvm-svn: 151242
2012-02-23 08:23:06 +00:00
Nick Lewycky 9d0da18597 Use the target-aware constant folder on expressions to improve the chance
they'll be simple enough to simulate, and to reduce the chance we'll encounter
equal but different simple pointer constants.

This removes the symptoms from PR11352 but is not a full fix. A proper fix would
either require a guarantee that two constant objects we simulate are folded
when equal, or a different way of handling equal pointers (ie., trying a
constantexpr icmp on them to see whether we know they're equal or non-equal or
unsure).

llvm-svn: 151093
2012-02-21 22:08:06 +00:00
Nick Lewycky 519561f418 Check for the correct size in the invariant marker.
llvm-svn: 151003
2012-02-20 23:32:26 +00:00
Nick Lewycky 60829a587a Rename class Evaluate to Evaluator and put it in an anonymous namespace.
llvm-svn: 150947
2012-02-20 03:25:59 +00:00
Nick Lewycky 73be5e31a6 Move EvaluateFunction and EvaluateBlock into a class, and make the class store
the information that they pass around between them. No functionality change!

llvm-svn: 150939
2012-02-19 23:26:27 +00:00
Nick Lewycky 68f9f9d9c8 Add support for invariant.start inside the static constructor evaluator. This is
useful to represent a variable that is const in the source but can't be constant
in the IR because of a non-trivial constructor. If globalopt evaluates the
constructor, and there was an invariant.start with no matching invariant.end
possible, it will mark the global constant afterwards.

llvm-svn: 150794
2012-02-17 06:59:21 +00:00
Nick Lewycky c1572e4c90 Handle InvokeInst in EvaluateBlock. Don't try to support exceptions, it's just
that no optz'ns have run yet to convert invokes to calls.

llvm-svn: 150326
2012-02-12 05:09:35 +00:00
Nick Lewycky f285256f72 false is totally null!
llvm-svn: 150324
2012-02-12 02:17:18 +00:00
Nick Lewycky 4b273cb7ea Remove redundant getAnalysis<> calls in GlobalOpt. Add a few Itanium ABI calls
to TargetLibraryInfo and use one of them in GlobalOpt.

llvm-svn: 150323
2012-02-12 02:15:20 +00:00
Nick Lewycky cf6aae686d Pass TargetData and TargetLibraryInfo through to the constant folder. Fixes a
few fixme's when TLI was added.

llvm-svn: 150322
2012-02-12 01:13:18 +00:00
Nick Lewycky 1480f1d3f9 Fix function name in comment to match actual name. Fix comments that are using
doxy-style on local variables to not do so. Fix one 80-col violation.

llvm-svn: 150320
2012-02-12 00:52:26 +00:00
Nick Lewycky 4231c41c64 Don't traverse the PHI nodes twice. No functionality change!
llvm-svn: 150319
2012-02-12 00:47:24 +00:00
Benjamin Kramer 1a4695a091 Tweak comment readability and grammar.
llvm-svn: 150183
2012-02-09 16:28:15 +00:00
Benjamin Kramer 487a3962c7 GlobalOpt: Be more aggressive about elminating side-effect free static dtors.
GlobalOpt runs early in the pipeline (before inlining) and complex class
hierarchies often introduce bitcasts or GEPs which weren't optimized away.
Teach it to ignore side-effect free instructions instead of depending on
other passes to remove them.

llvm-svn: 150174
2012-02-09 14:26:06 +00:00
Nick Lewycky 239fdf0f61 Split part of EvaluateFunction into a new EvaluateBlock method. No functionality
change.

llvm-svn: 149861
2012-02-06 08:24:44 +00:00
Nick Lewycky 52da72b12a Teach GlobalOpt to handle atomic accesses to globals.
* Most of the transforms come through intact by having each transformed load or
store copy the ordering and synchronization scope of the original.
 * The transform that turns a global only accessed in main() into an alloca
(since main is non-recursive) with a store of the initial value uses an
unordered store, since it's guaranteed to be the first thing to happen in main.
(Threads may have started before main (!) but they can't have the address of a
function local before the point in the entry block we insert our code.)
 * The heap-SRoA transforms are disabled in the face of atomic operations. This
can probably be improved; it seems odd to have atomic accesses to an alloca
that doesn't have its address taken.

AnalyzeGlobal keeps track of the strongest ordering found in any use of the
global. This is more information than we need right now, but it's cheap to
compute and likely to be useful.

llvm-svn: 149847
2012-02-05 19:56:38 +00:00
Nick Lewycky bbd1156b95 Clean up some whitespace and comments. No functionality change.
llvm-svn: 149845
2012-02-05 19:48:37 +00:00
Stepan Dyatkovskiy 513aaa5691 SwitchInst refactoring.
The purpose of refactoring is to hide operand roles from SwitchInst user (programmer). If you want to play with operands directly, probably you will need lower level methods than SwitchInst ones (TerminatorInst or may be User). After this patch we can reorganize SwitchInst operands and successors as we want.

What was done:

1. Changed semantics of index inside the getCaseValue method:
getCaseValue(0) means "get first case", not a condition. Use getCondition() if you want to resolve the condition. I propose don't mix SwitchInst case indexing with low level indexing (TI successors indexing, User's operands indexing), since it may be dangerous.
2. By the same reason findCaseValue(ConstantInt*) returns actual number of case value. 0 means first case, not default. If there is no case with given value, ErrorIndex will returned.
3. Added getCaseSuccessor method. I propose to avoid usage of TerminatorInst::getSuccessor if you want to resolve case successor BB. Use getCaseSuccessor instead, since internal SwitchInst organization of operands/successors is hidden and may be changed in any moment.
4. Added resolveSuccessorIndex and resolveCaseIndex. The main purpose of these methods is to see how case successors are really mapped in TerminatorInst.
4.1 "resolveSuccessorIndex" was created if you need to level down from SwitchInst to TerminatorInst. It returns TerminatorInst's successor index for given case successor.
4.2 "resolveCaseIndex" converts low level successors index to case index that curresponds to the given successor.

Note: There are also related compatability fix patches for dragonegg, klee, llvm-gcc-4.0, llvm-gcc-4.2, safecode, clang.
llvm-svn: 149481
2012-02-01 07:49:51 +00:00
Chris Lattner 0256be96f2 continue making the world safe for ConstantDataVector. At this point,
we should (theoretically optimize and codegen ConstantDataVector as well
as ConstantVector.

llvm-svn: 149116
2012-01-27 03:08:05 +00:00
Chris Lattner fa77500d96 Continue improving support for ConstantDataAggregate, and use the
new methods recently added to (sometimes greatly!) simplify code.

llvm-svn: 149024
2012-01-26 02:32:04 +00:00
Chris Lattner 6705883ad8 use Constant::getAggregateElement to simplify a bunch of code.
llvm-svn: 148934
2012-01-25 06:48:06 +00:00
David Blaikie 46a9f016c5 More dead code removal (using -Wunreachable-code)
llvm-svn: 148578
2012-01-20 21:51:11 +00:00
Eli Friedman 55fa49f32d PR11705, part 2: globalopt shouldn't put inttoptr/ptrtoint operations into global initializers if there's an implied extension or truncation.
llvm-svn: 147625
2012-01-05 23:03:32 +00:00
Chad Rosier 43a33066b4 Fix a few more places where TargetData/TargetLibraryInfo is not being passed.
Add FIXMEs to places that are non-trivial to fix.

llvm-svn: 145661
2011-12-02 01:26:24 +00:00
Chad Rosier e6de63dfc5 Last bit of TargetLibraryInfo propagation. Also fixed a case for TargetData
where it appeared beneficial to pass.
More of rdar://10500969

llvm-svn: 145630
2011-12-01 21:29:16 +00:00
Eli Friedman 1923a330e6 Refactor code from inlining and globalopt that checks whether a function definition is unused, and enhance it so it can tell that functions which are only used by a blockaddress are in fact dead. This probably doesn't happen much on most code, but the Linux kernel's _THIS_IP_ can trigger this issue with blockaddress. (GlobalDCE can also handle the given tescase, but we only run that at -O3.) Found while looking at PR11180.
llvm-svn: 142572
2011-10-20 05:23:42 +00:00
Benjamin Kramer 547b6c5ecd Stop emitting instructions with the name "tmp" they eat up memory and have to be uniqued, without any benefit.
If someone prefers %tmp42 to %42, run instnamer.

llvm-svn: 140634
2011-09-27 20:39:19 +00:00
Eli Friedman b8f30de527 Minor comment fixes.
llvm-svn: 137693
2011-08-16 00:20:11 +00:00
Eli Friedman 211e348eaa Update inter-procedural optimizations for atomic load/store.
llvm-svn: 137667
2011-08-15 22:16:46 +00:00