242 Commits

Author SHA1 Message Date
Matthias Braun
5e55477ae5 MachineRegionInfo: Fix pass initialization
- Adapt MachineBasicBlock::getName() to have the same behavior as the IR
  BasicBlock (Value::getName()).
- Add it to lib/CodeGen/CodeGen.cpp::initializeCodeGen so that it is linked in
  the CodeGen library.
- MachineRegionInfoPass's name conflicts with RegionInfoPass's name ("region").
- MachineRegionInfo should depend on MachineDominatorTree,
  MachinePostDominatorTree and MachineDominanceFrontier instead of their
  respective IR versions.
- Since there were no tests for this, add a X86 MIR test.

Patch by Francis Visoiu Mistrih<fvisoiumistrih@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@295518 91177308-0d34-0410-b5e6-96231b3b80d8
2017-02-18 00:41:16 +00:00
Taewook Oh
9fdcd96d07 Make MachineBasicBlock::updateTerminator to update DebugLoc as well
Summary:
Currently MachineBasicBlock::updateTerminator simply drops DebugLoc for newly created branch instructions, which may cause incorrect stepping and/or imprecise sample profile data. Below is an example:

```
  1 extern int bar(int x);
  2
  3 int foo(int *begin, int *end) {
  4   int *i;
  5   int ret = 0;
  6   for (
  7       i = begin ;
  8       i != end ;
  9       i++)
 10   {
 11       ret += bar(*i);
 12   }
 13   return ret;
 14 }
```

Below is a bitcode of 'foo' at the end of LLVM-IR level optimizations with -O3:

```
define i32 @foo(i32* readonly %begin, i32* readnone %end) !dbg !4 {
entry:
  %cmp6 = icmp eq i32* %begin, %end, !dbg !9
  br i1 %cmp6, label %for.end, label %for.body.preheader, !dbg !12

for.body.preheader:                               ; preds = %entry
  br label %for.body, !dbg !13

for.body:                                         ; preds = %for.body.preheader, %for.body
  %ret.08 = phi i32 [ %add, %for.body ], [ 0, %for.body.preheader ]
  %i.07 = phi i32* [ %incdec.ptr, %for.body ], [ %begin, %for.body.preheader ]
  %0 = load i32, i32* %i.07, align 4, !dbg !13, !tbaa !15
  %call = tail call i32 @bar(i32 %0), !dbg !19
  %add = add nsw i32 %call, %ret.08, !dbg !20
  %incdec.ptr = getelementptr inbounds i32, i32* %i.07, i64 1, !dbg !21
  %cmp = icmp eq i32* %incdec.ptr, %end, !dbg !9
  br i1 %cmp, label %for.end.loopexit, label %for.body, !dbg !12, !llvm.loop !22

for.end.loopexit:                                 ; preds = %for.body
  br label %for.end, !dbg !24

for.end:                                          ; preds = %for.end.loopexit, %entry
  %ret.0.lcssa = phi i32 [ 0, %entry ], [ %add, %for.end.loopexit ]
  ret i32 %ret.0.lcssa, !dbg !24
}
```

where

```
!12 = !DILocation(line: 6, column: 3, scope: !11)
```

. As you can see, the terminator of 'entry' block, which is a loop control branch, has a DebugLoc of line 6, column 3. Howerver, after the execution of 'MachineBlock::updateTerminator' function, which is triggered by MachineSinking pass, the DebugLoc info is dropped as below (see there's no debug-location for JNE_1):

```
  bb.0.entry:
    successors: %bb.4(0x30000000), %bb.1.for.body.preheader(0x50000000)
    liveins: %rdi, %rsi

    %6 = COPY %rsi
    %5 = COPY %rdi
    %8 = SUB64rr %5, %6, implicit-def %eflags, debug-location !9
    JNE_1 %bb.1.for.body.preheader, implicit %eflags
```

This patch addresses this issue and make newly created branch instructions to keep debug-location info.

Reviewers: aprantl, MatzeB, craig.topper, qcolombet

Reviewed By: qcolombet

Subscribers: qcolombet, llvm-commits

Differential Revision: https://reviews.llvm.org/D29596

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@294976 91177308-0d34-0410-b5e6-96231b3b80d8
2017-02-13 18:15:31 +00:00
Quentin Colombet
d87ddcb9f0 [MachineBasicBlock] Add a non-assert live-in accessor for debug mode.
With r291169, it is now not possible to access the live-in information
when the liveness is not properly tracked. Although this is want we want
in general, for debugging purpose we may want to still be able to
traverse this information even if it may not be accurate.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291317 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-07 00:46:30 +00:00
Matthias Braun
4700463eb1 CodeGen: Assert that liveness is up to date when reading block live-ins.
Add an assert that checks whether liveins are up to date before they are
used.

- Do not print liveins into .mir files anymore in situations where they
  are out of date anyway.
- The assert in the RegisterScavenger is superseded by the new one in
  livein_begin().
- Skip parts of the liveness updating logic in IfConversion.cpp when
  liveness isn't tracked anymore (just enough to avoid hitting the new
  assert()).

Differential Revision: https://reviews.llvm.org/D27562

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291169 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-05 20:01:19 +00:00
Matthias Braun
fe82f4a18b BranchRelaxation: Recompute live-ins when splitting a block
Factors out and reuses live-in computation code from BranchFolding.

Differential Revision: https://reviews.llvm.org/D27558

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290013 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-16 23:55:37 +00:00
Florian Hahn
f295c8c72c [codegen] Add generic functions to skip debug values.
Summary:
This commits moves skipDebugInstructionsForward and
skipDebugInstructionsBackward from lib/CodeGen/IfConversion.cpp
to include/llvm/CodeGen/MachineBasicBlock.h and updates
some codgen files to use them.

This refactoring was suggested in https://reviews.llvm.org/D27688
and I thought it's best to do the refactoring in a separate
review, but I could also put both changes in a single review
if that's preferred.

Also, the names for the functions aren't the snappiest and
I would be happy to rename them if anybody has suggestions. 

Reviewers: eli.friedman, iteratee, aprantl, MatzeB

Subscribers: MatzeB, llvm-commits

Differential Revision: https://reviews.llvm.org/D27782

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289933 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-16 11:10:26 +00:00
Krzysztof Parzyszek
d6ca3f019d Extract LaneBitmask into a separate type
Specifically avoid implicit conversions from/to integral types to
avoid potential errors when changing the underlying type. For example,
a typical initialization of a "full" mask was "LaneMask = ~0u", which
would result in a value of 0x00000000FFFFFFFF if the type was extended
to uint64_t.

Differential Revision: https://reviews.llvm.org/D27454


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289820 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-15 14:36:06 +00:00
Keith Walker
7435b28542 Place the lowered phi instruction(s) before the DEBUG_VALUE entry
When a phi node is finally lowered to a machine instruction it is
important that the lowered "load" instruction is placed before the
associated DEBUG_VALUE entry describing the value loaded.

Renamed the existing SkipPHIsAndLabels to SkipPHIsLabelsAndDebug to
more fully describe that it also skips debug entries. Then used the
"new" function SkipPHIsAndLabels when the debug information should not
be skipped when placing the lowered "load" instructions so that it is
placed before the debug entries.

Differential Revision: https://reviews.llvm.org/D23760 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281727 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-16 14:07:29 +00:00
Duncan P. N. Exon Smith
a66f054162 ADT: Never allocate nodes in iplist<> and ilist<>
Remove createNode() and any API that depending on it, and add
HasCreateNode to the list of checks for HasObsoleteCustomizations.  Now
an ilist *never* allocates (this was already true for iplist).

This factors out all the differences between iplist and ilist.  I'll aim
to rename both to "owning_ilist" eventually, to call out the interesting
(not exactly intrusive) ownership semantics.  In the meantime, I've left
both names around to reduce code churn.

One of the deleted APIs is the ilist copy constructor.  I've lifted up
and tested iplist::cloneFrom (ala simple_ilist::cloneFrom) as a
replacement.

Users of ilist<> and iplist<> that want the list to allocate nodes have
a few options:
- use std::list;
- use AllocatorList or BumpPtrList (or build a similarly trivial list);
- use cloneFrom (which is explicit at the call site); or
- allocate at the call site.

See r280573, r281177, r281181, and r281182 for examples of what to do if
you're updating out-of-tree code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281184 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-11 23:43:43 +00:00
Duncan P. N. Exon Smith
d546df8daf CodeGen: Give MachineBasicBlock::reverse_iterator a handle to the current MI
Now that MachineBasicBlock::reverse_instr_iterator knows when it's at
the end (since r281168 and r281170), implement
MachineBasicBlock::reverse_iterator directly on top of an
ilist::reverse_iterator by adding an IsReverse template parameter to
MachineInstrBundleIterator.  This replaces another hard-to-reason-about
use of std::reverse_iterator on list iterators, matching the changes for
ilist::reverse_iterator from r280032 (see the "out of scope" section at
the end of that commit message).  MachineBasicBlock::reverse_iterator
now has a handle to the current node and has obvious invalidation
semantics.

r280032 has a more detailed explanation of how list-style reverse
iterators (invalidated when the pointed-at node is deleted) are
different from vector-style reverse iterators like std::reverse_iterator
(invalidated on every operation).  A great motivating example is this
commit's changes to lib/CodeGen/DeadMachineInstructionElim.cpp.

Note: If your out-of-tree backend deletes instructions while iterating
on a MachineBasicBlock::reverse_iterator or converts between
MachineBasicBlock::iterator and MachineBasicBlock::reverse_iterator,
you'll need to update your code in similar ways to r280032.  The
following table might help:

                  [Old]              ==>             [New]
        delete &*RI, RE = end()                   delete &*RI++
        RI->erase(), RE = end()                   RI++->erase()
      reverse_iterator(I)                 std::prev(I).getReverse()
      reverse_iterator(I)                          ++I.getReverse()
    --reverse_iterator(I)                            I.getReverse()
      reverse_iterator(std::next(I))                 I.getReverse()
                RI.base()                std::prev(RI).getReverse()
                RI.base()                         ++RI.getReverse()
              --RI.base()                           RI.getReverse()
     std::next(RI).base()                           RI.getReverse()

(For more details, have a look at r280032.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281172 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-11 18:51:28 +00:00
Duncan P. N. Exon Smith
6037e199c8 CodeGen: Turn on sentinel tracking for MachineInstr iterators
This is a prep commit before fixing MachineBasicBlock::reverse_iterator
invalidation semantics, ala r281167 for ilist::reverse_iterator.  This
changes MachineBasicBlock::Instructions to track which node is the
sentinel regardless of LLVM_ENABLE_ABI_BREAKING_CHECKS.

There's almost no functionality change (aside from ABI).  However, in
the rare configuration:

    #if !defined(NDEBUG) && !defined(LLVM_ENABLE_ABI_BREAKING_CHECKS)

the isKnownSentinel() assertions in ilist_iterator<>::operator* suddenly
have teeth for MachineInstr.  If these assertions start firing for your
out-of-tree backend, have a look at the suggestions in the commit
message for r279314, and at some of the commits leading up to it that
avoid dereferencing the end() iterator.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281168 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-11 16:38:18 +00:00
Tim Shen
b62ba77b89 s/static inline/static/ for headers I have changed in r279475. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280257 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-31 16:48:13 +00:00
Duncan P. N. Exon Smith
a55b262ca2 CodeGen: Fixup for r280128, since GCC isn't as permissive as Clang
Fixes the bots, e.g.:
http://lab.llvm.org:8011/builders/lldb-x86_64-ubuntu-14.04-buildserver/builds/10055

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280135 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-30 19:11:11 +00:00
Duncan P. N. Exon Smith
9c80b35060 ADT: Split ilist_node_traits into alloc and callback, NFC
Many lists want to override only allocation semantics, or callbacks for
iplist.  Split these up to prevent code duplication.
- Specialize ilist_alloc_traits to change the implementations of
  deleteNode() and createNode().
- One common desire is to do nothing deleteNode() and disable
  createNode().  Specialize ilist_alloc_traits to inherit from
  ilist_noalloc_traits for that behaviour.
- Specialize ilist_callback_traits to use the addNodeToList(),
  removeNodeFromList(), and transferNodesFromList() callbacks.

As a drive-by, add some coverage to the callback-related unit tests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280128 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-30 18:40:47 +00:00
Duncan P. N. Exon Smith
1d79fff9e6 ADT: Give ilist<T>::reverse_iterator a handle to the current node
Reverse iterators to doubly-linked lists can be simpler (and cheaper)
than std::reverse_iterator.  Make it so.

In particular, change ilist<T>::reverse_iterator so that it is *never*
invalidated unless the node it references is deleted.  This matches the
guarantees of ilist<T>::iterator.

(Note: MachineBasicBlock::iterator is *not* an ilist iterator, but a
MachineInstrBundleIterator<MachineInstr>.  This commit does not change
MachineBasicBlock::reverse_iterator, but it does update
MachineBasicBlock::reverse_instr_iterator.  See note at end of commit
message for details on bundle iterators.)

Given the list (with the Sentinel showing twice for simplicity):

     [Sentinel] <-> A <-> B <-> [Sentinel]

the following is now true:
 1. begin() represents A.
 2. begin() holds the pointer for A.
 3. end() represents [Sentinel].
 4. end() holds the poitner for [Sentinel].
 5. rbegin() represents B.
 6. rbegin() holds the pointer for B.
 7. rend() represents [Sentinel].
 8. rend() holds the pointer for [Sentinel].

The changes are #6 and #8.  Here are some properties from the old
scheme (which used std::reverse_iterator):
- rbegin() held the pointer for [Sentinel] and rend() held the pointer
  for A;
- operator*() cost two dereferences instead of one;
- converting from a valid iterator to its valid reverse_iterator
  involved a confusing increment; and
- "RI++->erase()" left RI invalid.  The unintuitive replacement was
  "RI->erase(), RE = end()".

With vector-like data structures these properties are hard to avoid
(since past-the-beginning is not a valid pointer), and don't impose a
real cost (since there's still only one dereference, and all iterators
are invalidated on erase).  But with lists, this was a poor design.

Specifically, the following code (which obviously works with normal
iterators) now works with ilist::reverse_iterator as well:

    for (auto RI = L.rbegin(), RE = L.rend(); RI != RE;)
      fooThatMightRemoveArgFromList(*RI++);

Converting between iterator and reverse_iterator for the same node uses
the getReverse() function.

    reverse_iterator iterator::getReverse();
    iterator reverse_iterator::getReverse();

Why doesn't iterator <=> reverse_iterator conversion use constructors?

In order to catch and update old code, reverse_iterator does not even
have an explicit conversion from iterator.  It wouldn't be safe because
there would be no reasonable way to catch all the bugs from the changed
semantic (see the changes at call sites that are part of this patch).

Old code used this API:

    std::reverse_iterator::reverse_iterator(iterator);
    iterator std::reverse_iterator::base();

Here's how to update from old code to new (that incorporates the
semantic change), assuming I is an ilist<>::iterator and RI is an
ilist<>::reverse_iterator:

            [Old]         ==>          [New]
    reverse_iterator(I)       (--I).getReverse()
    reverse_iterator(I)         ++I.getReverse()
  --reverse_iterator(I)           I.getReverse()
    reverse_iterator(++I)         I.getReverse()
          RI.base()          (--RI).getReverse()
          RI.base()            ++RI.getReverse()
        --RI.base()              RI.getReverse()
      (++RI).base()              RI.getReverse()
  delete &*RI, RE = end()         delete &*RI++
  RI->erase(), RE = end()         RI++->erase()

=======================================
Note: bundle iterators are out of scope
=======================================

MachineBasicBlock::iterator, also known as
MachineInstrBundleIterator<MachineInstr>, is a wrapper to represent
MachineInstr bundles.  The idea is that each operator++ takes you to the
beginning of the next bundle.  Implementing a sane reverse iterator for
this is harder than ilist.  Here are the options:
- Use std::reverse_iterator<MBB::i>.  Store a handle to the beginning of
  the next bundle.  A call to operator*() runs a loop (usually
  operator--() will be called 1 time, for unbundled instructions).
  Increment/decrement just works.  This is the status quo.
- Store a handle to the final node in the bundle.  A call to operator*()
  still runs a loop, but it iterates one time fewer (usually
  operator--() will be called 0 times, for unbundled instructions).
  Increment/decrement just works.
- Make the ilist_sentinel<MachineInstr> *always* store that it's the
  sentinel (instead of just in asserts mode).  Then the bundle iterator
  can sniff the sentinel bit in operator++().

I initially tried implementing the end() option as part of this commit,
but updating iterator/reverse_iterator conversion call sites was
error-prone.  I have a WIP series of patches that implements the final
option.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280032 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-30 00:13:12 +00:00
Tim Shen
22fca38c9c [GraphTraits] Replace all NodeType usage with NodeRef
This should finish the GraphTraits migration.

Differential Revision: http://reviews.llvm.org/D23730


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279475 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-22 21:09:30 +00:00
Duncan P. N. Exon Smith
d47df8775d ADT: Remove ilist_*sentinel_traits, NFC
Remove all the dead code around ilist_*sentinel_traits.  This is a
follow-up to gutting them as part of r279314 (originally r278974),
staged to prevent broken builds in sub-projects.

Uses were removed from clang in r279457 and lld in r279458.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279473 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-22 20:51:00 +00:00
Duncan P. N. Exon Smith
3e97be26b9 ADT: Share code for embedded sentinel traits, NFC
Share code for the (mostly problematic) embedded sentinel traits.
- Move the LLVM_NO_SANITIZE("object-size") attribute to
  ilist_half_embedded_sentinel_traits and ilist_embedded_sentinel_traits
  (previously it spread throughout the code duplication).
- Add an ilist_full_embedded_sentinel_traits which has no UB (but has
  the downside of storing the complete node).
- Replace all the custom sentinel traits in LLVM with a declaration of
  ilist_sentinel_traits that inherits from one of the embedded sentinel
  traits classes.

There are still custom sentinel traits in other LLVM subprojects.  I'll
remove those in a follow-up.

Nothing at all should be changing here, this is just rearranging code.
Note that the final goal here is to remove the sentinel traits
altogether, settling on the memory layout of
ilist_half_embedded_sentinel_traits without the UB.  This intermediate
step moves the logic into ilist.h.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@278513 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-12 15:00:55 +00:00
Tim Shen
a9ed4cc01c [ADT] NFC: Generalize GraphTraits requirement of "NodeType *" in interfaces to "NodeRef", and migrate SCCIterator.h to use NodeRef
Summary: By generalize the interface, users are able to inject more flexible Node token into the algorithm, for example, a pair of vector<Node>* and index integer. Currently I only migrated SCCIterator to use NodeRef, but more is coming. It's a NFC.

Reviewers: dblaikie, chandlerc

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D22937

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277399 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-01 22:32:20 +00:00
Matthias Braun
d170aeaa5b MachineFunction: Add a const modifier to print() parameter
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268657 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-05 18:14:43 +00:00
David Majnemer
e7edf2d8d2 [WinEH] Update SplitAnalysis::computeLastSplitPoint to cope with multiple EH successors
We didn't have logic to correctly handle CFGs where there was more than
one EH-pad successor (these are novel with WinEH).
There were situations where a register was live in one exceptional
successor but not another but the code as written would only consider
the first exceptional successor it found.

This resulted in split points which were insufficiently early if an
invoke was present.

This fixes PR27501.

N.B.  This removes getLandingPadSuccessor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267412 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-25 14:31:32 +00:00
Quentin Colombet
f2cd15729a [MachineBasicBlock] Make the pass argument truly mandatory when
splitting edges.

MachineBasicBlock::SplitCriticalEdges will crash if a nullptr would have
been passed for the Pass argument. Do not allow that by turning this
argument into a reference.
The alternative would have been to make the Pass a truly optional
argument, but although this is easy to do, I was afraid users using it
like this would not be aware the livness information, dominator tree and
such would silently be broken.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267052 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-21 21:01:13 +00:00
Quentin Colombet
e4d168d65f [MachineBasicBlock] Refactor SplitCriticalEdge to expose a query API.
Introduce canSplitCriticalEdge, so that clients can now query whether or
not a critical edge can be split without actually needing to split it.
This may be useful when gathering information for cost models for
instance.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267046 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-21 20:46:27 +00:00
Duncan P. N. Exon Smith
42e18357c5 CodeGen: Take MachineInstr& in SlotIndexes and LiveIntervals, NFC
Take MachineInstr by reference instead of by pointer in SlotIndexes and
the SlotIndex wrappers in LiveIntervals.  The MachineInstrs here are
never null, so this cleans up the API a bit.  It also incidentally
removes a few implicit conversions from MachineInstrBundleIterator to
MachineInstr* (see PR26753).

At a couple of call sites it was convenient to convert to a range-based
for loop over MachineBasicBlock::instr_begin/instr_end, so I added
MachineBasicBlock::instrs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262115 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-27 06:40:41 +00:00
Duncan P. N. Exon Smith
110284e56c CodeGen: Bring back MachineBasicBlock::iterator::getInstrIterator()...
This is a little embarrassing.

When I reverted r261504 (getIterator() => getInstrIterator()) in
r261567, I did a `git grep` to see if there were new calls to
`getInstrIterator()` that I needed to migrate.  There were 10-20 hits,
and I blindly did a `sed ...` before calling `ninja check`.

However, these were `MachineInstrBundleIterator::getInstrIterator()`,
which predated r261567.  Perhaps coincidentally, these had an identical
name and return type.

This commit undoes my careless sed and restores
`MachineBasicBlock::iterator::getInstrIterator()`.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261577 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-22 21:30:15 +00:00
Duncan P. N. Exon Smith
20a62528ef Revert "CodeGen: MachineInstr::getIterator() => getInstrIterator(), NFC"
This reverts commit r261504, since it's not obvious the new name is
better:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160222/334298.html

I'll recommit if we get consensus that it's the right direction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261567 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-22 20:49:58 +00:00
Duncan P. N. Exon Smith
b64deed8bb CodeGen: Split bundle_iterator into a separate file, NFC
Split MachineBasicBlock::bundle_iterator into a separate file, and
rename the class to MachineBundleIterator.

This is a precursor to adding a `MachineInstr::getBundleIterator()`
accessor, which will eventually let us delete the final call to
getNodePtrUnchecked(), and then remove the UB from ilist_iterator.

As a drive-by, I removed an unnecessary second template parameter.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261502 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-21 22:05:50 +00:00
Cong Hou
5ae2b850eb Normalize MBB's successors' probabilities in several locations.
This patch adds some missing calls to MBB::normalizeSuccProbs() in several
locations where it should be called. Those places are found by checking if the
sum of successors' probabilities is approximate one in MachineBlockPlacement
pass with some instrumented code (not in this patch).


Differential revision: http://reviews.llvm.org/D15259




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255455 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-13 09:26:17 +00:00
Matthias Braun
f43272c76e CodeGen: Redo analyzePhysRegs() and computeRegisterLiveness()
computeRegisterLiveness() was broken in that it reported dead for a
register even if a subregister was alive. I assume this was because the
results of analayzePhysRegs() are hard to understand with respect to
subregisters.

This commit: Changes the results of analyzePhysRegs (=struct
PhysRegInfo) to be clearly understandable, also renames the fields to
avoid silent breakage of third-party code (and improve the grammar).

Fix all (two) users of computeRegisterLiveness() in llvm: By reenabling
it and removing workarounds for the bug.

This fixes http://llvm.org/PR24535 and http://llvm.org/PR25033

Differential Revision: http://reviews.llvm.org/D15320

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255362 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-11 19:42:09 +00:00
Craig Topper
e6bc7d1f0d Use make_range to reduce mentions of iterator type. NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254872 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-06 05:08:07 +00:00
Cong Hou
5155021519 Replace all weight-based interfaces in MBB with probability-based interfaces, and update all uses of old interfaces.
(This is the second attempt to submit this patch. The first caused two assertion
 failures and was reverted. See https://llvm.org/bugs/show_bug.cgi?id=25687)

The patch in http://reviews.llvm.org/D13745 is broken into four parts:

1. New interfaces without functional changes (http://reviews.llvm.org/D13908).
2. Use new interfaces in SelectionDAG, while in other passes treat probabilities
as weights (http://reviews.llvm.org/D14361).
3. Use new interfaces in all other passes.
4. Remove old interfaces.

This patch is 3+4 above. In this patch, MBB won't provide weight-based
interfaces any more, which are totally replaced by probability-based ones.
The interface addSuccessor() is redesigned so that the default probability is
unknown. We allow unknown probabilities but don't allow using it together
with known probabilities in successor list. That is to say, we either have a
list of successors with all known probabilities, or all unknown
probabilities. In the latter case, we assume each successor has 1/N
probability where N is the number of successors. An assertion checks if the
user is attempting to add a successor with the disallowed mixed use as stated
above. This can help us catch many misuses.

All uses of weight-based interfaces are now updated to use probability-based
ones.


Differential revision: http://reviews.llvm.org/D14973




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254377 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-01 05:29:22 +00:00
Hans Wennborg
8e83fe2e97 Revert r254348: "Replace all weight-based interfaces in MBB with probability-based interfaces, and update all uses of old interfaces."
and the follow-up r254356: "Fix a bug in MachineBlockPlacement that may cause assertion failure during BranchProbability construction."

Asserts were firing in Chromium builds. See PR25687.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254366 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-01 03:49:42 +00:00
Cong Hou
92989cbe84 Replace all weight-based interfaces in MBB with probability-based interfaces, and update all uses of old interfaces.
The patch in http://reviews.llvm.org/D13745 is broken into four parts:

1. New interfaces without functional changes (http://reviews.llvm.org/D13908).
2. Use new interfaces in SelectionDAG, while in other passes treat probabilities
as weights (http://reviews.llvm.org/D14361).
3. Use new interfaces in all other passes.
4. Remove old interfaces.

This patch is 3+4 above. In this patch, MBB won't provide weight-based
interfaces any more, which are totally replaced by probability-based ones.
The interface addSuccessor() is redesigned so that the default probability is
unknown. We allow unknown probabilities but don't allow using it together
with known probabilities in successor list. That is to say, we either have a
list of successors with all known probabilities, or all unknown
probabilities. In the latter case, we assume each successor has 1/N
probability where N is the number of successors. An assertion checks if the
user is attempting to add a successor with the disallowed mixed use as stated
above. This can help us catch many misuses.

All uses of weight-based interfaces are now updated to use probability-based
ones.


Differential revision: http://reviews.llvm.org/D14973




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254348 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-01 00:02:51 +00:00
Cong Hou
1763c9fe3a Modify the interface BranchProbability::normalizeProbabilities to let it accept a pair of iterators. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253417 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-18 01:03:19 +00:00
Duncan P. N. Exon Smith
6426aea54e ADT: Avoid relying on UB in ilist_node::getNextNode()
Re-implement `ilist_node::getNextNode()` and `getPrevNode()` without
relying on the sentinel having a "next" pointer.  Instead, get access to
the owning list and compare against the `begin()` and `end()` iterators.

This only works when the node *can* get access to the owning list.  The
new support is in `ilist_node_with_parent<>`, and any class `Ty`
inheriting from `ilist_node<NodeTy>` that wants `getNextNode()` and/or
`getPrevNode()` should inherit from
`ilist_node_with_parent<NodeTy, ParentTy>` instead.  The requirements:

  - `NodeTy` must have a `getParent()` function that returns the parent.
  - `ParentTy` must have a `getSublistAccess()` static that, given a(n
    ignored) `NodeTy*` (to determine which list), returns a member field
    pointer to the appropriate `ilist<>`.

This isn't the cleanest way to get access to the owning list, but it
leverages the API already used in the IR hierarchy (see, e.g.,
`Instruction::getSublistAccess()`).

If anyone feels like ripping out the calls to `getNextNode()` and
`getPrevNode()` and replacing with direct iterator logic, they can also
remove the access function, etc., but as an incremental step, I'm
maintaining the API where it's currently used in tree.

If these requirements are *not* met, call sites with access to the ilist
can call `iplist<NodeTy>::getNextNode(NodeTy*)` directly, as in
ilistTest.cpp.

Why rewrite this?

The old code was broken, calling `getNext()` on a sentinel that possibly
didn't have a "next" pointer at all!  The new code avoids that
particular flavour of UB (see the commit message for r252538 for more
details about the "lucky" memory layout that made this function so
interesting).

There's still some UB here: the end iterator gets downcast to `NodeTy*`,
even when it's a sentinel (which is typically
`ilist_half_node<NodeTy*>`).  I'll tackle that in follow-up commits.
See this llvm-dev thread for more details:
http://lists.llvm.org/pipermail/llvm-dev/2015-October/091115.html

What's the danger?

There might be some code that relies on `getNextNode()` or
`getPrevNode()` *never* returning `nullptr` -- i.e., that relies on them
being broken when the sentinel is an `ilist_half_node<NodeTy>`.  I tried
to root out those cases with the audits I did leading up to r252380, but
it's possible I missed one or two.  I hope not.

(If (1) you have out-of-tree code, (2) you've reverted r252380
temporarily, and (3) you get some weird crashes with this commit, then I
recommend un-reverting r252380 and auditing the compile errors looking
for "strange" implicit conversions.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252694 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-11 02:26:42 +00:00
Reid Kleckner
f0a04c06ab [WinEH] Mark funclet entries and exits as clobbering all registers
Summary:
In this implementation, LiveIntervalAnalysis invents a few register
masks on basic block boundaries that preserve no registers. The nice
thing about this is that it prevents the prologue inserter from thinking
it needs to spill all XMM CSRs, because it doesn't see any explicit
physreg defs in the MI.

Reviewers: MatzeB, qcolombet, JosephTremoulet, majnemer

Subscribers: MatzeB, llvm-commits

Differential Revision: http://reviews.llvm.org/D14407

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252318 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-06 17:06:38 +00:00
Cong Hou
178bfbdf60 Add new interfaces to MBB for manipulating successors with probabilities instead of weights. NFC.
This is part-1 of the patch that replaces all edge weights in MBB by
probabilities, which only adds new interfaces. No functional changes.

Differential revision: http://reviews.llvm.org/D13908




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252083 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-04 21:37:58 +00:00
Cong Hou
d4f04a7e27 Create a new interface addSuccessorWithoutWeight(MBB*) in MBB to add successors when optimization is disabled.
When optimization is disabled, edge weights that are stored in MBB won't be used so that we don't have to store them. Currently, this is done by adding successors with default weight 0, and if all successors have default weights, the weight list will be empty. But that the weight list is empty doesn't mean disabled optimization (as is stated several times in MachineBasicBlock.cpp): it may also mean all successors just have default weights.

We should discourage using default weights when adding successors, because it is very easy for users to forget update the correct edge weights instead of using default ones (one exception is that the MBB only has one successor). In order to detect such usages, it is better to differentiate using default weights from the case when optimizations is disabled.

In this patch, a new interface addSuccessorWithoutWeight(MBB*) is created for when optimization is disabled. In this case, MBB will try to maintain an empty weight list, but it cannot guarantee this as for many uses of addSuccessor() whether optimization is disabled or not is not checked. But it can guarantee that if optimization is enabled, then the weight list always has the same size of the successor list.

Differential revision: http://reviews.llvm.org/D13963




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251429 91177308-0d34-0410-b5e6-96231b3b80d8
2015-10-27 17:59:36 +00:00
Duncan P. N. Exon Smith
9cb8e12ce1 CodeGen: Start removing implicit conversions to/from list iterators, NFC
Start removing implicit conversions to/from list iterators in CodeGen,
ala r249782 for IR.  A lot more to go after this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@249851 91177308-0d34-0410-b5e6-96231b3b80d8
2015-10-09 16:54:49 +00:00
Duncan P. N. Exon Smith
ac3b52bb0d CodeGen: s/protected:/private:/ in MachineBasicBlock, NFC
Nothing inherits from `MachineBasicBlock`, so this should have no real
functionality change.  Just makes the code easier to understand.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@249473 91177308-0d34-0410-b5e6-96231b3b80d8
2015-10-06 21:48:31 +00:00
David Majnemer
0ba86faae2 [WinEH] Teach AsmPrinter about funclets
Summary:
Funclets have been turned into functions by the time they hit the object
file.  Make sure that they have decent names for the symbol table and
CFI directives explaining how to reason about their prologues.

Differential Revision: http://reviews.llvm.org/D13261

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248824 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-29 20:12:33 +00:00
Cong Hou
abae8489f1 Rename some function arguments in MachineBasicBlock.cpp/h by turning the first letter into upper case. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248821 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-29 19:46:09 +00:00
Matthias Braun
dfc5b65a74 TargetRegisterInfo: Add typedef unsigned LaneBitmask and use it where apropriate; NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248623 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-25 21:51:14 +00:00
Matthias Braun
63daa1436f MachineBasicBlock: Factor out common code into isReturnBlock()
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248617 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-25 21:25:19 +00:00
Reid Kleckner
7ad3e0e009 [WinEH] Add and use hasEHPadSuccessor instead of getLandingPadSuccessor
getLandingPadSuccessor assumes that each invoke can have at most one EH
pad successor, but WinEH invokes can have more than one. Two out of
three callers of getLandingPadSuccessor don't use the returned
landingpad, so we can make them use this simple predicate instead.

Eventually we'll have to circle back and fix SplitKit.cpp so that
register allocation works. Baby steps.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247904 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-17 17:19:40 +00:00
Matthias Braun
af5ff60200 Save LaneMask with livein registers
With subregister liveness enabled we can detect the case where only
parts of a register are live in, this is expressed as a 32bit lanemask.
The current code only keeps registers in the live-in list and therefore
enumerated all subregisters affected by the lanemask. This turned out to
be too conservative as the subregister may also cover additional parts
of the lanemask which are not live. Expressing a given lanemask by
enumerating a minimum set of subregisters is computationally expensive
so the best solution is to simply change the live-in list to store the
lanemasks as well. This will reduce memory usage for targets using
subregister liveness and slightly increase it for other targets

Differential Revision: http://reviews.llvm.org/D12442

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247171 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-09 18:08:03 +00:00
Reid Kleckner
c0e64ada5c [WinEH] Add some support for code generating catchpad
We can now run 32-bit programs with empty catch bodies.  The next step
is to change PEI so that we get funclet prologues and epilogues.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246235 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-27 23:27:47 +00:00
Matthias Braun
fbf4c2b2e1 MachineBasicBlock: Use MCPhysReg instead of unsigned in livein API
This is friendlier to the readers as it makes it clear that the API is
not meant for vregs but just for physregs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245977 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-25 22:05:55 +00:00
Matthias Braun
56dd2d0886 MachineBasicBlock: Add liveins() method returning an iterator_range
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245895 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-24 22:59:52 +00:00
Alex Lorenz
5d09c2f25d MIR Serialization: Change MIR syntax - use custom syntax for MBBs.
This commit modifies the way the machine basic blocks are serialized - now the
machine basic blocks are serialized using a custom syntax instead of relying on
YAML primitives. Instead of using YAML mappings to represent the individual
machine basic blocks in a machine function's body, the new syntax uses a single
YAML block scalar which contains all of the machine basic blocks and
instructions for that function.

This is an example of a function's body that uses the old syntax:

    body:
      - id: 0
        name: entry
        instructions:
          - '%eax = MOV32r0 implicit-def %eflags'
          - 'RETQ %eax'
    ...

The same body is now written like this:

    body: |
      bb.0.entry:
        %eax = MOV32r0 implicit-def %eflags
        RETQ %eax
    ...

This syntax change is motivated by the fact that the bundled machine
instructions didn't map that well to the old syntax which was using a single
YAML sequence to store all of the machine instructions in a block. The bundled
machine instructions internally use flags like BundledPred and BundledSucc to
determine the bundles, and serializing them as MI flags using the old syntax
would have had a negative impact on the readability and the ease of editing
for MIR files. The new syntax allows me to serialize the bundled machine
instructions using a block construct without relying on the internal flags,
for example:

   BUNDLE implicit-def dead %itstate, implicit-def %s1 ... {
      t2IT 1, 24, implicit-def %itstate
      %s1 = VMOVS killed %s0, 1, killed %cpsr, implicit killed %itstate
   }

This commit also converts the MIR testcases to the new syntax. I developed
a script that can convert from the old syntax to the new one. I will post the
script on the llvm-commits mailing list in the thread for this commit.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244982 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-13 23:10:16 +00:00