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132 Commits

Author SHA1 Message Date
Peter Collingbourne
e3f12b0e68 IR: New representation for CFI and virtual call optimization pass metadata.
The bitset metadata currently used in LLVM has a few problems:

1. It has the wrong name. The name "bitset" refers to an implementation
   detail of one use of the metadata (i.e. its original use case, CFI).
   This makes it harder to understand, as the name makes no sense in the
   context of virtual call optimization.

2. It is represented using a global named metadata node, rather than
   being directly associated with a global. This makes it harder to
   manipulate the metadata when rebuilding global variables, summarise it
   as part of ThinLTO and drop unused metadata when associated globals are
   dropped. For this reason, CFI does not currently work correctly when
   both CFI and vcall opt are enabled, as vcall opt needs to rebuild vtable
   globals, and fails to associate metadata with the rebuilt globals. As I
   understand it, the same problem could also affect ASan, which rebuilds
   globals with a red zone.

This patch solves both of those problems in the following way:

1. Rename the metadata to "type metadata". This new name reflects how
   the metadata is currently being used (i.e. to represent type information
   for CFI and vtable opt). The new name is reflected in the name for the
   associated intrinsic (llvm.type.test) and pass (LowerTypeTests).

2. Attach metadata directly to the globals that it pertains to, rather
   than using the "llvm.bitsets" global metadata node as we are doing now.
   This is done using the newly introduced capability to attach
   metadata to global variables (r271348 and r271358).

See also: http://lists.llvm.org/pipermail/llvm-dev/2016-June/100462.html

Differential Revision: http://reviews.llvm.org/D21053

llvm-svn: 273729
2016-06-24 21:21:32 +00:00
Daniel Berlin
cde81efccb Add MemoryAccess creation and PHI creation APIs to MemorySSA
Reviewers: george.burgess.iv, gberry, hfinkel

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D21463

llvm-svn: 273295
2016-06-21 18:39:20 +00:00
George Burgess IV
7651319b9a [MemorySSA] Clean up unit tests a tiny bit. NFC.
We recently made MemorySSA own the walker it creates. As a part of this,
the MSSA test fixture was changed to have a `Walker*` instead of a
`unique_ptr<Walker>`. So, we no longer need to do `&*Walker` in order to
get a `Walker*`.

llvm-svn: 273189
2016-06-20 19:13:07 +00:00
Geoff Berry
a619b50bd5 [MemorySSA] Port to new pass manager
Add support for the new pass manager to MemorySSA pass.

Change MemorySSA to be computed eagerly upon construction.

Change MemorySSAWalker to be owned by the MemorySSA object that creates
it.

Reviewers: dberlin, george.burgess.iv

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D19664

llvm-svn: 271432
2016-06-01 21:30:40 +00:00
Peter Collingbourne
e728c537a2 Cloning: Clean up the interface to the CloneFunction function.
Remove the ModuleLevelChanges argument, and the ability to create new
subprograms for cloned functions. The latter was added without review in
r203662, but it has no in-tree clients (all non-test callers pass false
for ModuleLevelChanges [1], so it isn't reachable outside of tests). It
also isn't clear that adding a duplicate subprogram to the compile unit is
always the right thing to do when cloning a function within a module. If
this functionality comes back it should be accompanied with a more concrete
use case.

Furthermore, all in-tree clients add the returned function to the module.
Since that's pretty much the only sensible thing you can do with the function,
just do that in CloneFunction.

[1] http://llvm-cs.pcc.me.uk/lib/Transforms/Utils/CloneFunction.cpp/rCloneFunction

Differential Revision: http://reviews.llvm.org/D18628

llvm-svn: 269110
2016-05-10 20:23:24 +00:00
George Burgess IV
fd2f0313de [MemorySSA] Fix bugs in walker; refactor unittests a bit.
This patch fixes two somewhat related bugs in MemorySSA's caching
walker. These bugs were found because D19695 brought up the problem
that we'd have defs cached to themselves, which is incorrect.

The bugs this fixes are:

- We would sometimes skip the nearest clobber of a MemoryAccess, because
  we would query our cache for a given potential clobber before
  checking if the potential clobber is the clobber we're looking for.
  The cache entry for the potential clobber would point to the nearest
  clobber *of the potential clobber*, so if that was a cache hit, we'd
  ignore the potential clobber entirely.

- There are times (sometimes in DFS, sometimes in the getClobbering...
  functions) where we would insert cache entries that say a def
  clobbers itself.

There's a bit of common code between the fixes for the bugs, so they
aren't split out into multiple commits.

This patch also adds a few unit tests, and refactors existing tests a
bit to reduce the duplication of setup code.

llvm-svn: 268087
2016-04-29 18:42:55 +00:00
Mehdi Amini
9ff867f98c [NFC] Header cleanup
Removed some unused headers, replaced some headers with forward class declarations.

Found using simple scripts like this one:
clear && ack --cpp -l '#include "llvm/ADT/IndexedMap.h"' | xargs grep -L 'IndexedMap[<]' | xargs grep -n --color=auto 'IndexedMap'

Patch by Eugene Kosov <claprix@yandex.ru>

Differential Revision: http://reviews.llvm.org/D19219

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266595
2016-04-18 09:17:29 +00:00
Duncan P. N. Exon Smith
a4defb35fe ValueMapper: Stop memoizing ConstantAsMetadata
Stop memoizing ConstantAsMetadata in ValueMapper::mapMetadata.  Now we
have to recompute it, but these metadata aren't particularly common, and
it restricts the lifetime of the Metadata map unnecessarily.

(The motivation is that I have a patch which uses a single Metadata map
for the lifetime of IRMover.  Mehdi profiled r266446 with the patch
applied and we saw a pretty big speedup in lib/Linker.)

llvm-svn: 266513
2016-04-16 03:39:44 +00:00
Duncan P. N. Exon Smith
a6bf7ac10c Reapply "ValueMapper: Eliminate cross-file co-recursion, NFC"
This reverts commit r266507, reapplying r266503 (and r266505
"ValueMapper: Use API from r266503 in unit tests, NFC") completely
unchanged.

I reverted because of a bot failure here:
  http://lab.llvm.org:8011/builders/lld-x86_64-freebsd/builds/16810/

However, looking more closely, the failure was from a host-compiler
crash (clang 3.7.1) when building:
  lib/CodeGen/AsmPrinter/CMakeFiles/LLVMAsmPrinter.dir/DwarfAccelTable.cpp.o

I didn't modify that file, or anything it includes, with that commit.

The next build (which hadn't picked up my revert) got past it:
  http://lab.llvm.org:8011/builders/lld-x86_64-freebsd/builds/16811/

I think this was just unfortunate timing.  I suppose the bot must be
flakey.

llvm-svn: 266510
2016-04-16 02:29:55 +00:00
Duncan P. N. Exon Smith
51eff3c93d Revert "ValueMapper: Eliminate cross-file co-recursion, NFC"
This reverts commit r266503, in case it's the root cause of this bot
failure:

  http://lab.llvm.org:8011/builders/lld-x86_64-freebsd/builds/16810

I'm also reverting r266505 -- "ValueMapper: Use API from r266503 in unit
tests, NFC" -- since it's in the way.

llvm-svn: 266507
2016-04-16 02:05:33 +00:00
Duncan P. N. Exon Smith
05297fa732 ValueMapper: Use API from r266503 in unit tests, NFC
I'm not in a hurry to migrate all the users, but the unit tests at least
should use the new API.

llvm-svn: 266505
2016-04-16 01:40:24 +00:00
Adrian Prantl
fb3abba237 [PR27284] Reverse the ownership between DICompileUnit and DISubprogram.
Currently each Function points to a DISubprogram and DISubprogram has a
scope field. For member functions the scope is a DICompositeType. DIScopes
point to the DICompileUnit to facilitate type uniquing.

Distinct DISubprograms (with isDefinition: true) are not part of the type
hierarchy and cannot be uniqued. This change removes the subprograms
list from DICompileUnit and instead adds a pointer to the owning compile
unit to distinct DISubprograms. This would make it easy for ThinLTO to
strip unneeded DISubprograms and their transitively referenced debug info.

Motivation
----------

Materializing DISubprograms is currently the most expensive operation when
doing a ThinLTO build of clang.

We want the DISubprogram to be stored in a separate Bitcode block (or the
same block as the function body) so we can avoid having to expensively
deserialize all DISubprograms together with the global metadata. If a
function has been inlined into another subprogram we need to store a
reference the block containing the inlined subprogram.

Attached to https://llvm.org/bugs/show_bug.cgi?id=27284 is a python script
that updates LLVM IR testcases to the new format.

http://reviews.llvm.org/D19034
<rdar://problem/25256815>

llvm-svn: 266446
2016-04-15 15:57:41 +00:00
Mehdi Amini
ea195a382e Remove every uses of getGlobalContext() in LLVM (but the C API)
At the same time, fixes InstructionsTest::CastInst unittest: yes
you can leave the IR in an invalid state and exit when you don't
destroy the context (like the global one), no longer now.

This is the first part of http://reviews.llvm.org/D19094

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266379
2016-04-14 21:59:01 +00:00
Duncan P. N. Exon Smith
9437b219c2 ValueMapper: Resolve cycles on the new nodes
Fix a major bug from r265456.  Although it's now much rarer, ValueMapper
sometimes has to duplicate cycles.  The
might-transitively-reference-a-temporary counts don't decrement on their
own when there are cycles, and you need to call MDNode::resolveCycles to
fix it.

r265456 was checking the input nodes to see if they were unresolved.
This is useless; they should never be unresolved.  Instead we should
check the output nodes and resolve cycles on them.

llvm-svn: 266258
2016-04-13 22:54:01 +00:00
Duncan P. N. Exon Smith
695a2ff629 ValueMapper: Don't memoize metadata when RF_NoModuleLevelChanges
Prevent the Metadata side-table in ValueMap from growing unnecessarily
when RF_NoModuleLevelChanges.  As a drive-by, make ValueMap::hasMD,
which apparently had no users until I used it here for testing, actually
compile.

llvm-svn: 265828
2016-04-08 18:49:36 +00:00
Duncan P. N. Exon Smith
238a64e1c5 ValueMapper: Stop memoizing MDStrings
Stop adding MDString to the Metadata section of the ValueMap in
MapMetadata.  It blows up the size of the map for no benefit, since we
can always return quickly anyway.

There is a potential follow-up that I don't think I'll push on right
away, but maybe someone else is interested:  stop checking for a
pre-mapped MDString, and move the `isa<MDString>()` checks in
Mapper::mapSimpleMetadata and MDNodeMapper::getMappedOp in front of the
`VM.getMappedMD()` calls.  While this would preclude explicitly
remapping MDStrings it would probably be a little faster.

llvm-svn: 265827
2016-04-08 18:47:02 +00:00
Duncan P. N. Exon Smith
89c4487fee Reapply "ValueMapper: Treat LocalAsMetadata more like function-local Values"
This reverts commit r265765, reapplying r265759 after changing a call from
LocalAsMetadata::get to ValueAsMetadata::get (and adding a unit test).  When a
local value is mapped to a constant (like "i32 %a" => "i32 7"), the new debug
intrinsic operand may no longer be pointing at a local.

    http://lab.llvm.org:8080/green/job/clang-stage1-configure-RA_build/19020/

The previous coommit message follows:

--

This is a partial re-commit -- maybe more of a re-implementation -- of
r265631 (reverted in r265637).

This makes RF_IgnoreMissingLocals behave (almost) consistently between
the Value and the Metadata hierarchy.  In particular:

  - MapValue returns nullptr or "metadata !{}" for missing locals in
    MetadataAsValue/LocalAsMetadata bridging paris, depending on
    the RF_IgnoreMissingLocals flag.

  - MapValue doesn't memoize LocalAsMetadata-related results.

  - MapMetadata no longer deals with LocalAsMetadata or
    RF_IgnoreMissingLocals at all.  (This wasn't in r265631 at all, but
    I realized during testing it would make the patch simpler with no
    loss of generality.)

r265631 went too far, making both functions universally ignore
RF_IgnoreMissingLocals.  This broke building (e.g.) compiler-rt.
Reassociate (and possibly other passes) don't currently maintain
dominates-use invariants for metadata operands, resulting in IR like
this:

    define void @foo(i32 %arg) {
      call void @llvm.some.intrinsic(metadata i32 %x)
      %x = add i32 1, i32 %arg
    }

If the inliner chooses to inline @foo into another function, then
RemapInstruction will call `MapValue(metadata i32 %x)` and assert that
the return is not nullptr.

I've filed PR27273 to add a Verifier check and fix the underlying
problem in the optimization passes.

As a workaround, return `!{}` instead of nullptr for unmapped
LocalAsMetadata when RF_IgnoreMissingLocals is unset.  Otherwise, match
the behaviour of r265631.

Original commit message:

    ValueMapper: Make LocalAsMetadata match function-local Values

    Start treating LocalAsMetadata similarly to function-local members of
    the Value hierarchy in MapValue and MapMetadata.

      - Don't memoize them.
      - Return nullptr if they are missing.

    This also cleans up ConstantAsMetadata to stop listening to the
    RF_IgnoreMissingLocals flag.

llvm-svn: 265768
2016-04-08 03:13:22 +00:00
Duncan P. N. Exon Smith
957a52adbf Revert "ValueMapper: Treat LocalAsMetadata more like function-local Values"
This reverts commit r265759, since even this limited version breaks some
bots:
  http://lab.llvm.org:8011/builders/clang-ppc64be-linux/builds/3311
  http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-autoconf/builds/17696

This also reverts r265761 "ValueMapper: Unduplicate
RF_NoModuleLevelChanges check, NFC", since I had trouble separating it
from r265759.

llvm-svn: 265765
2016-04-08 00:56:21 +00:00
Duncan P. N. Exon Smith
1f42c70b4f ValueMapper: Treat LocalAsMetadata more like function-local Values
This is a partial re-commit -- maybe more of a re-implementation -- of
r265631 (reverted in r265637).

This makes RF_IgnoreMissingLocals behave (almost) consistently between
the Value and the Metadata hierarchy.  In particular:

  - MapValue returns nullptr or "metadata !{}" for missing locals in
    MetadataAsValue/LocalAsMetadata bridging paris, depending on
    the RF_IgnoreMissingLocals flag.

  - MapValue doesn't memoize LocalAsMetadata-related results.

  - MapMetadata no longer deals with LocalAsMetadata or
    RF_IgnoreMissingLocals at all.  (This wasn't in r265631 at all, but
    I realized during testing it would make the patch simpler with no
    loss of generality.)

r265631 went too far, making both functions universally ignore
RF_IgnoreMissingLocals.  This broke building (e.g.) compiler-rt.
Reassociate (and possibly other passes) don't currently maintain
dominates-use invariants for metadata operands, resulting in IR like
this:

    define void @foo(i32 %arg) {
      call void @llvm.some.intrinsic(metadata i32 %x)
      %x = add i32 1, i32 %arg
    }

If the inliner chooses to inline @foo into another function, then
RemapInstruction will call `MapValue(metadata i32 %x)` and assert that
the return is not nullptr.

I've filed PR27273 to add a Verifier check and fix the underlying
problem in the optimization passes.

As a workaround, return `!{}` instead of nullptr for unmapped
LocalAsMetadata when RF_IgnoreMissingLocals is unset.  Otherwise, match
the behaviour of r265631.

Original commit message:

    ValueMapper: Make LocalAsMetadata match function-local Values

    Start treating LocalAsMetadata similarly to function-local members of
    the Value hierarchy in MapValue and MapMetadata.

      - Don't memoize them.
      - Return nullptr if they are missing.

    This also cleans up ConstantAsMetadata to stop listening to the
    RF_IgnoreMissingLocals flag.

llvm-svn: 265759
2016-04-08 00:33:44 +00:00
Duncan P. N. Exon Smith
e5b711647a Revert "ValueMapper: Make LocalAsMetadata match function-local Values"
This reverts commit r265631, since it caused bot failures:
http://lab.llvm.org:8011/builders/clang-ppc64be-linux/builds/3256
http://lab.llvm.org:8011/builders/clang-cmake-aarch64-42vma/builds/7272

Looks like something is depending on the old behaviour.  I'll try to
track it down and recommit.

llvm-svn: 265637
2016-04-07 02:10:50 +00:00
Duncan P. N. Exon Smith
3863b4df3a ValueMapper: Allow RF_IgnoreMissingLocals and RF_NullMapMissingGlobalValues
Remove the assertion that disallowed the combination, since
RF_IgnoreMissingLocals should have no effect on globals.  As it happens,
RF_NullMapMissingGlobalValues asserted in MapValue(Constant*,...), so I
also changed a cast to a cast_or_null to get my test passing.

llvm-svn: 265633
2016-04-07 01:22:45 +00:00
Duncan P. N. Exon Smith
4b4ae21d40 ValueMapper: Make LocalAsMetadata match function-local Values
Start treating LocalAsMetadata similarly to function-local members of
the Value hierarchy in MapValue and MapMetadata.

  - Don't memoize them.
  - Return nullptr if they are missing.

This also cleans up ConstantAsMetadata to stop listening to the
RF_IgnoreMissingLocals flag.

llvm-svn: 265631
2016-04-07 01:08:39 +00:00
Duncan P. N. Exon Smith
7d92710523 ValueMapper: Rewrite Mapper::mapMetadata without recursion
This commit completely rewrites Mapper::mapMetadata (the implementation
of llvm::MapMetadata) using an iterative algorithm.  The guts of the new
algorithm are in MDNodeMapper::map, the entry function in a new class.

Previously, Mapper::mapMetadata performed a recursive exploration of the
graph with eager "just in case there's a reason" malloc traffic.

The new algorithm has these benefits:

  - New nodes and temporaries are not created eagerly.
  - Uniquing cycles are not duplicated (see new unit test).
  - No recursion.

Given a node to map, it does this:

 1. Use a worklist to perform a post-order traversal of the transitively
    referenced unmapped nodes.

 2. Track which nodes will change operands, and which will have new
    addresses in the mapped scheme.  Propagate the changes through the
    POT until fixed point, to pick up uniquing cycles that need to
    change.

 3. Map all the distinct nodes without touching their operands.  If
    RF_MoveDistinctMetadata, they get mapped to themselves; otherwise,
    they get mapped to clones.

 4. Map the uniqued nodes (bottom-up), lazily creating temporaries for
    forward references as needed.

 5. Remap the operands of the distinct nodes.

Mehdi helped me out by profiling this with -flto=thin.  On his workload
(importing/etc. for opt.cpp), MapMetadata sped up by 15%, contributed
about 50% less to persistent memory, and made about 100x fewer calls to
malloc.  The speedup is less than I'd hoped.  The profile mainly blames
DenseMap lookups; perhaps there's a way to reduce them (e.g., by
disallowing remapping of MDString).

It would be nice to break the strange remaining recursion on the Value
side: MapValue => materializeInitFor => RemapInstruction => MapValue.  I
think we could do this by having materializeInitFor return a worklist of
things to be remapped.

llvm-svn: 265456
2016-04-05 20:23:21 +00:00
Duncan P. N. Exon Smith
5e94641b4a ValueMapper: Add support for seeding metadata with nullptr
Support seeding a ValueMap with nullptr for Metadata entries, a
situation I didn't consider in the Metadata/Value split.

I added a ValueMapper::getMappedMD accessor that returns an
Optional<Metadata*> with the mapped (possibly null) metadata.  IRMover
needs to use this to avoid modifying the map when it's checking for
unneeded subprograms.  I updated a call from bugpoint since I find the
new code clearer.

llvm-svn: 265228
2016-04-02 17:04:38 +00:00
Duncan P. N. Exon Smith
700ae13d2f Document end of anonymous namespaces, NFC
Prevent clang-format from deleting the preceding newline.

llvm-svn: 265227
2016-04-02 16:45:51 +00:00
Peter Collingbourne
5990eb01ac LowerBitSets: Move declarations to separate namespace.
Should fix modules build.

llvm-svn: 265176
2016-04-01 18:46:50 +00:00
Peter Collingbourne
c940ae83b9 Cloning: Reduce complexity of debug info cloning and fix correctness issue.
Commit r260791 contained an error in that it would introduce a cross-module
reference in the old module. It also introduced O(N^2) complexity in the
module cloner by requiring the entire module to be visited for each function.
Fix both of these problems by avoiding use of the CloneDebugInfoMetadata
function (which is only designed to do intra-module cloning) and cloning
function-attached metadata in the same way that we clone all other metadata.

Differential Revision: http://reviews.llvm.org/D18583

llvm-svn: 264935
2016-03-30 22:05:13 +00:00
Daniel Berlin
e9b459fbed Really fix ASAN leak/etc issues with MemorySSA unittests
llvm-svn: 262519
2016-03-02 21:16:28 +00:00
Daniel Berlin
c49f8e9e7a Revert "Fix ASAN detected errors in code and test" (it was not meant to be committed yet)
This reverts commit 890bbccd600ba1eb050353d06a29650ad0f2eb95.

llvm-svn: 262512
2016-03-02 20:36:22 +00:00
Daniel Berlin
1e51dad27e Fix ASAN detected errors in code and test
llvm-svn: 262511
2016-03-02 20:27:29 +00:00
Chandler Carruth
e597ed0112 [AA] Hoist the logic to reformulate various AA queries in terms of other
parts of the AA interface out of the base class of every single AA
result object.

Because this logic reformulates the query in terms of some other aspect
of the API, it would easily cause O(n^2) query patterns in alias
analysis. These could in turn be magnified further based on the number
of call arguments, and then further based on the number of AA queries
made for a particular call. This ended up causing problems for Rust that
were actually noticable enough to get a bug (PR26564) and probably other
places as well.

When originally re-working the AA infrastructure, the desire was to
regularize the pattern of refinement without losing any generality.
While I think it was successful, that is clearly proving to be too
costly. And the cost is needless: we gain no actual improvement for this
generality of making a direct query to tbaa actually be able to
re-use some other alias analysis's refinement logic for one of the other
APIs, or some such. In short, this is entirely wasted work.

To the extent possible, delegation to other API surfaces should be done
at the aggregation layer so that we can avoid re-walking the
aggregation. In fact, this significantly simplifies the logic as we no
longer need to smuggle the aggregation layer into each alias analysis
(or the TargetLibraryInfo into each alias analysis just so we can form
argument memory locations!).

However, we also have some delegation logic inside of BasicAA and some
of it even makes sense. When the delegation logic is baking in specific
knowledge of aliasing properties of the LLVM IR, as opposed to simply
reformulating the query to utilize a different alias analysis interface
entry point, it makes a lot of sense to restrict that logic to
a different layer such as BasicAA. So one aspect of the delegation that
was in every AA base class is that when we don't have operand bundles,
we re-use function AA results as a fallback for callsite alias results.
This relies on the IR properties of calls and functions w.r.t. aliasing,
and so seems a better fit to BasicAA. I've lifted the logic up to that
point where it seems to be a natural fit. This still does a bit of
redundant work (we query function attributes twice, once via the
callsite and once via the function AA query) but it is *exactly* twice
here, no more.

The end result is that all of the delegation logic is hoisted out of the
base class and into either the aggregation layer when it is a pure
retargeting to a different API surface, or into BasicAA when it relies
on the IR's aliasing properties. This should fix the quadratic query
pattern reported in PR26564, although I don't have a stand-alone test
case to reproduce it.

It also seems general goodness. Now the numerous AAs that don't need
target library info don't carry it around and depend on it. I think
I can even rip out the general access to the aggregation layer and only
expose that in BasicAA as it is the only place where we re-query in that
manner.

However, this is a non-trivial change to the AA infrastructure so I want
to get some additional eyes on this before it lands. Sadly, it can't
wait long because we should really cherry pick this into 3.8 if we're
going to go this route.

Differential Revision: http://reviews.llvm.org/D17329

llvm-svn: 262490
2016-03-02 15:56:53 +00:00
Daniel Berlin
3242d3bab3 Fix SHARED_LIBS build
llvm-svn: 262439
2016-03-02 00:58:48 +00:00
Daniel Berlin
07e4e63d22 Add the beginnings of an update API for preserving MemorySSA
Summary:
This adds the beginning of an update API to preserve MemorySSA.  In particular,
this patch adds a way to remove memory SSA accesses when instructions are
deleted.

It also adds relevant unit testing infrastructure for MemorySSA's API.

(There is an actual user of this API, i will make that diff dependent on this one.  In practice, a ton of opt passes remove memory instructions, so it's hopefully an obviously useful API :P)

Reviewers: hfinkel, reames, george.burgess.iv

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D17157

llvm-svn: 262362
2016-03-01 18:46:54 +00:00
Keno Fischer
2e799f5e5e [Cloning] Clone every Function's Debug Info
Summary:
Export the CloneDebugInfoMetadata utility, which clones all debug info
associated with a function into the first module. Also use this function
in CloneModule on each function we clone (the CloneFunction entrypoint
already does this).

Without this, cloning a module will lead to DI quality regressions,
especially since r252219 reversed the Function <-> DISubprogram edge
(before we could get lucky and have this edge preserved if the
DISubprogram itself was, e.g. due to location metadata).

This was verified to fix missing debug information in julia and
a unittest to verify the new behavior is included.

Patch by Yichao Yu! Thanks!

Reviewers: loladiro, pcc
Differential Revision: http://reviews.llvm.org/D17165

llvm-svn: 260791
2016-02-13 02:04:29 +00:00
Peter Collingbourne
54e8749794 WholeProgramDevirt: introduce.
This pass implements whole program optimization of virtual calls in cases
where we know (via bitset information) that the list of callees is fixed. This
includes the following:

- Single implementation devirtualization: if a virtual call has a single
  possible callee, replace all calls with a direct call to that callee.

- Virtual constant propagation: if the virtual function's return type is an
  integer <=64 bits and all possible callees are readnone, for each class and
  each list of constant arguments: evaluate the function, store the return
  value alongside the virtual table, and rewrite each virtual call as a load
  from the virtual table.

- Uniform return value optimization: if the conditions for virtual constant
  propagation hold and each function returns the same constant value, replace
  each virtual call with that constant.

- Unique return value optimization for i1 return values: if the conditions
  for virtual constant propagation hold and a single vtable's function
  returns 0, or a single vtable's function returns 1, replace each virtual
  call with a comparison of the vptr against that vtable's address.

Differential Revision: http://reviews.llvm.org/D16795

llvm-svn: 260312
2016-02-09 22:50:34 +00:00
Chris Bieneman
1b8d4f74aa Remove autoconf support
Summary:
This patch is provided in preparation for removing autoconf on 1/26. The proposal to remove autoconf on 1/26 was discussed on the llvm-dev thread here: http://lists.llvm.org/pipermail/llvm-dev/2016-January/093875.html

"I felt a great disturbance in the [build system], as if millions of [makefiles] suddenly cried out in terror and were suddenly silenced. I fear something [amazing] has happened."
- Obi Wan Kenobi

Reviewers: chandlerc, grosbach, bob.wilson, tstellarAMD, echristo, whitequark

Subscribers: chfast, simoncook, emaste, jholewinski, tberghammer, jfb, danalbert, srhines, arsenm, dschuff, jyknight, dsanders, joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D16471

llvm-svn: 258861
2016-01-26 21:29:08 +00:00
Rafael Espindola
f20bc23b7c Return a std::unique_ptr from CloneModule. NFC.
llvm-svn: 255078
2015-12-08 23:57:17 +00:00
Peter Collingbourne
5b721561aa DI: Reverse direction of subprogram -> function edge.
Previously, subprograms contained a metadata reference to the function they
described. Because most clients need to get or set a subprogram for a given
function rather than the other way around, this created unneeded inefficiency.

For example, many passes needed to call the function llvm::makeSubprogramMap()
to build a mapping from functions to subprograms, and the IR linker needed to
fix up function references in a way that caused quadratic complexity in the IR
linking phase of LTO.

This change reverses the direction of the edge by storing the subprogram as
function-level metadata and removing DISubprogram's function field.

Since this is an IR change, a bitcode upgrade has been provided.

Fixes PR23367. An upgrade script for textual IR for out-of-tree clients is
attached to the PR.

Differential Revision: http://reviews.llvm.org/D14265

llvm-svn: 252219
2015-11-05 22:03:56 +00:00
Duncan P. N. Exon Smith
43390ff2fc unittests: Remove implicit ilist iterator conversions, NFC
llvm-svn: 250843
2015-10-20 18:30:20 +00:00
Eric Christopher
fc91b95e28 Remove DIFile from createSubroutineType.
Patch by Amaury Sechet with a small modification by me.

llvm-svn: 250374
2015-10-15 06:56:10 +00:00
Benjamin Kramer
fded9fa4a4 [RemoveDuplicatePHINodes] Start over after removing a PHI.
This makes RemoveDuplicatePHINodes more effective and fixes an assertion
failure. Triggering the assertions requires a DenseSet reallocation
so this change only contains a constructive test.

I'll explain the issue with a small example. In the following function
there's a duplicate PHI, %4 and %5 are identical. When this is found
the DenseSet in RemoveDuplicatePHINodes contains %2, %3 and %4.

define void @F() {
  br label %1

; <label>:1                                       ; preds = %1, %0
  %2 = phi i32 [ 42, %0 ], [ %4, %1 ]
  %3 = phi i32 [ 42, %0 ], [ %5, %1 ]
  %4 = phi i32 [ 42, %0 ], [ 23, %1 ]
  %5 = phi i32 [ 42, %0 ], [ 23, %1 ]
  br label %1
}

after RemoveDuplicatePHINodes runs the function looks like this. %3 has
changed and is now identical to %2, but RemoveDuplicatePHINodes never
saw this.

define void @F() {
  br label %1

; <label>:1                                       ; preds = %1, %0
  %2 = phi i32 [ 42, %0 ], [ %4, %1 ]
  %3 = phi i32 [ 42, %0 ], [ %4, %1 ]
  %4 = phi i32 [ 42, %0 ], [ 23, %1 ]
  br label %1
}

If the DenseSet does a reallocation now it will reinsert all
keys and stumble over %3 now having a different hash value than it had
when inserted into the map for the first time. This change clears the
set whenever a PHI is deleted and starts the progress from the
beginning, allowing %3 to be deleted and avoiding inconsistent DenseSet
state. This potentially has a negative performance impact because
it rescans all PHIs, but I don't think that this ever makes a difference
in practice.

llvm-svn: 246694
2015-09-02 19:52:23 +00:00
Duncan P. N. Exon Smith
a6c2e1e60b Linker: Move distinct MDNodes instead of cloning
Instead of cloning distinct `MDNode`s when linking in a module, just
move them over.  The module linker destroys the source module, so the
old node would otherwise just be leaked on the context.  Create the new
node in place.  This also reduces the number of cloned uniqued nodes
(since it's less likely their operands have changed).

This mapping strategy is only correct when we're discarding the source,
so the linker turns it on via a ValueMapper flag, `RF_MoveDistinctMDs`.

There's nothing observable in terms of `llvm-link` output here: the
linked module should be semantically identical.

I'll be adding more 'distinct' nodes to the debug info metadata graph in
order to break uniquing cycles, so the benefits of this will partly come
in future commits.  However, we should get some gains immediately, since
we have a fair number of 'distinct' `DILocation`s being linked in.

llvm-svn: 243883
2015-08-03 17:09:38 +00:00
Duncan P. N. Exon Smith
80ade4fb4d DI: Rewrite the DIBuilder local variable API
Replace the general `createLocalVariable()` with two more specific
functions: `createParameterVariable()` and `createAutoVariable()`, and
rewrite the documentation.

Besides cleaning up the API, this avoids exposing the fake DWARF tags
`DW_TAG_arg_variable` and `DW_TAG_auto_variable` to frontends, and is
preparation for removing them completely.

llvm-svn: 243764
2015-07-31 17:55:53 +00:00
David Majnemer
cd7100d557 [Cloning] Teach CloneModule about personality functions
CloneModule didn't take into account that it needed to remap the value
using values in the module.

This fixes PR23992.

llvm-svn: 241122
2015-06-30 22:14:01 +00:00
Duncan P. N. Exon Smith
09b5c9c24d IR: Give 'DI' prefix to debug info metadata
Finish off PR23080 by renaming the debug info IR constructs from `MD*`
to `DI*`.  The last of the `DIDescriptor` classes were deleted in
r235356, and the last of the related typedefs removed in r235413, so
this has all baked for about a week.

Note: If you have out-of-tree code (like a frontend), I recommend that
you get everything compiling and tests passing with the *previous*
commit before updating to this one.  It'll be easier to keep track of
what code is using the `DIDescriptor` hierarchy and what you've already
updated, and I think you're extremely unlikely to insert bugs.  YMMV of
course.

Back to *this* commit: I did this using the rename-md-di-nodes.sh
upgrade script I've attached to PR23080 (both code and testcases) and
filtered through clang-format-diff.py.  I edited the tests for
test/Assembler/invalid-generic-debug-node-*.ll by hand since the columns
were off-by-three.  It should work on your out-of-tree testcases (and
code, if you've followed the advice in the previous paragraph).

Some of the tests are in badly named files now (e.g.,
test/Assembler/invalid-mdcompositetype-missing-tag.ll should be
'dicompositetype'); I'll come back and move the files in a follow-up
commit.

llvm-svn: 236120
2015-04-29 16:38:44 +00:00
Duncan P. N. Exon Smith
8bc0dcc184 DebugInfo: Remove DIArray and DITypeArray typedefs
Remove the `DIArray` and `DITypeArray` typedefs, preferring the
underlying types (`DebugNodeArray` and `MDTypeRefArray`, respectively).

llvm-svn: 235413
2015-04-21 20:07:38 +00:00
Duncan P. N. Exon Smith
8911bb4284 DebugInfo: Drop rest of DIDescriptor subclasses
Delete the remaining subclasses of (the already deleted) `DIDescriptor`.
Part of PR23080.

llvm-svn: 235404
2015-04-21 18:44:06 +00:00
Duncan P. N. Exon Smith
dc9077df15 DebugInfo: Delete subclasses of DIScope
Delete subclasses of (the already defunct) `DIScope`, updating users to
use the raw pointers from the `Metadata` hierarchy directly.

llvm-svn: 235356
2015-04-20 22:10:08 +00:00
Duncan P. N. Exon Smith
13554f3cb5 DebugInfo: Remove DIType
This is the last major parent class, so I'll probably start deleting
classes in batches now.  Looks like many of the references to the DI*
hierarchy were updated organically along the way.

llvm-svn: 235331
2015-04-20 18:52:06 +00:00
Duncan P. N. Exon Smith
6e0f299baf DebugInfo: Remove DIDescriptor from the DIBuilder API
As a step toward killing `DIDescriptor` and its subclasses, remove it
from the `DIBuilder` API.  Replace the subclasses with appropriate
pointers from the new debug info hierarchy.  There are a couple of
possible surprises in type choices for out-of-tree frontends:

  - Subroutine types: `MDSubroutineType`, not `MDCompositeTypeBase`.
  - Composite types: `MDCompositeType`, not `MDCompositeTypeBase`.
  - Scopes: `MDScope`, not `MDNode`.
  - Generic debug info nodes: `DebugNode`, not `MDNode`.

This is part of PR23080.

llvm-svn: 235111
2015-04-16 16:36:23 +00:00