Summary:
MetadataAsValue uses a canonical format that strips the MDNode if it
contains only a single constant value. This triggers an assertion when
trying to cast the value to a MDNode.
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D7165
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227319 91177308-0d34-0410-b5e6-96231b3b80d8
querying of the pass registry.
The pass manager relies on the static registry of PassInfo objects to
perform all manner of its functionality. I don't understand why it does
much of this. My very vague understanding is that this registry is
touched both during static initialization *and* while each pass is being
constructed. As a consequence it is hard to make accessing it not
require a acquiring some lock. This lock ends up in the hot path of
setting up, tearing down, and invaliditing analyses in the legacy pass
manager.
On most systems you can observe this as a non-trivial % of the time
spent in 'ninja check-llvm'. However, I haven't really seen it be more
than 1% in extreme cases of compiling more real-world software,
including LTO.
Unfortunately, some of the GPU JITs are seeing this taking essentially
all of their time because they have very small IR running through
a small pass pipeline very many times (at least, this is the vague
understanding I have of it).
This patch tries to minimize the cost of looking up PassInfo objects by
leveraging the fact that the objects themselves are immutable and they
are allocated separately on the heap and so don't have their address
change. It also requires a change I made the last time I tried to debug
this problem which removed the ability to de-register a pass from the
registry. This patch creates a single access path to these objects
inside the PMTopLevelManager which memoizes the result of querying the
registry. This is somewhat gross as I don't really know if
PMTopLevelManager is the *right* place to put it, and I dislike using
a mutable member to memoize things, but it seems to work.
For long-lived pass managers this should completely eliminate
the cost of acquiring locks to look into the pass registry once the
memoized cache is warm. For 'ninja check' I measured about 1.5%
reduction in CPU time and in total time on a machine with 32 hardware
threads. For normal compilation, I don't know how much this will help,
sadly. We will still pay the cost while we populate the memoized cache.
I don't think it will hurt though, and for LTO or compiles with many
small functions it should still be a win. However, for tight loops
around a pass manager with many passes and small modules, this will help
tremendously. On the AArch64 backend I saw nearly 50% reductions in time
to complete 2000 cycles of spinning up and tearing down the pipeline.
Measurements from Owen of an actual long-lived pass manager show more
along the lines of 10% improvements.
Differential Revision: http://reviews.llvm.org/D7213
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227299 91177308-0d34-0410-b5e6-96231b3b80d8
This change reverts the interesting parts of 226311 (and 227046). This change introduced two problems, and I've been convinced that an alternate approach is preferrable anyways.
The bugs were:
- Registery appears to require all users be within the same linkage unit. After this change, asking for "statepoint-example" in Transform/ would sometimes get you nullptr, whereas asking the same question in CodeGen would return the right GCStrategy. The correct long term fix is to get rid of the utter hack which is Registry, but I don't have time for that right now. 227046 appears to have been an attempt to fix this, but I don't believe it does so completely.
- GCMetadataPrinter::finishAssembly was being called more than once per GCStrategy. Each Strategy was being added to the GCModuleInfo multiple times.
Once I get time again, I'm going to split GCModuleInfo into the gc.root specific part and a GCStrategy owning Analysis pass. I'm probably also going to kill off the Registry. Once that's done, I'll move the new GCStrategyAnalysis and all built in GCStrategies into Analysis. (As original suggested by Chandler.) This will accomplish my original goal of being able to access GCStrategy from Transform/ without adding all of the builtin GCs to IR/.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227109 91177308-0d34-0410-b5e6-96231b3b80d8
These things are potentially used for non-DWARF data (see the discussion
in PR22235), so take the `Dwarf` out of the name. Since the new name
gives fewer clues, update the doxygen to properly describe what they
are.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226874 91177308-0d34-0410-b5e6-96231b3b80d8
During `MDNode::deleteTemporary()`, call `replaceAllUsesWith(nullptr)`
to update all tracking references to `nullptr`.
This fixes PR22280, where inverted destruction order between tracking
references and the temporaries themselves caused a use-after-free in
`LLParser`.
An alternative fix would be to add an assertion that there are no users,
and continue to fix inverted destruction order in clients (like
`LLParser`), but instead I decided to make getting-teardown-right easy.
(If someone disagrees let me know.)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226866 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Some parsers need references back to the option they are members of. This is used for handling the argument string as well as by the various pass name parsers for making pass names into flags.
Making parsers that need to refer back to the option have a reference to the option eliminates some of the members of various parsers, and enables further code cleanup.
Reviewers: dexonsmith
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D7131
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226864 91177308-0d34-0410-b5e6-96231b3b80d8
Specifically, gc.result benefits from this greatly. Instead of:
gc.result.int.*
gc.result.float.*
gc.result.ptr.*
...
We now have a gc.result.* that can specialize to literally any type.
Differential Revision: http://reviews.llvm.org/D7020
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226857 91177308-0d34-0410-b5e6-96231b3b80d8
With the appropriate Verifier changes, exactracting the result out of a
statepoint wrapping a vararg function crashes. However, a void vararg
function works fine: commit this first step.
Differential Revision: http://reviews.llvm.org/D7071
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226599 91177308-0d34-0410-b5e6-96231b3b80d8
ConstantArrays constructed during linking can cause quadratic memory
explosion. An example is the ConstantArrays constructed when linking in
GlobalVariables with appending linkage.
Releasing all unused constants can cause a 20% LTO compile-time
slowdown for a large application. So this commit releases unused ConstantArrays
only.
rdar://19040716. It reduces memory footprint from 20+G to 6+G.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226592 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r226542, effectively reapplying r226540. This time,
initialize `IsEmpty` in the copy and move constructors as well.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226545 91177308-0d34-0410-b5e6-96231b3b80d8
Now that the clone methods used by `MapMetadata()` don't do any
remapping (and return a temporary), they make more sense as member
functions on `MDNode` (and subclasses).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226541 91177308-0d34-0410-b5e6-96231b3b80d8
Change `HeaderBuilder` API to work well even when it's not starting with
a tag. There's already one case like this, and the tag is moving
elsewhere as part of PR22235.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226540 91177308-0d34-0410-b5e6-96231b3b80d8
Rather than relying on updating switch statements correctly, detect
whether `setHash()` exists in the subclass. If so, call
`recalculateHash()` and `setHash(0)` appropriately.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226531 91177308-0d34-0410-b5e6-96231b3b80d8
As part of PR22235, introduce `DwarfNode` and `GenericDwarfNode`. The
former is a metadata node with a DWARF tag. The latter matches our
current (generic) schema of a header with string (and stringified
integer) data and an arbitrary number of operands.
This doesn't move it into place yet; that change will require a large
number of testcase updates.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226529 91177308-0d34-0410-b5e6-96231b3b80d8
Swap usage of `SubclassData32` and `MDNodeSubclassData`, and rename
`MDNodeSubclassData` to `NumUnresolved`. Small drive-by cleanup to
`countUnresolvedOperands()` since otherwise the name clash with local
vars named `NumUnresolved` would be confusing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226523 91177308-0d34-0410-b5e6-96231b3b80d8
As pointed out in r226501, the distinction between `MDNode` and
`UniquableMDNode` is confusing. When we need subclasses of `MDNode`
that don't use all its functionality it might make sense to break it
apart again, but until then this makes the code clearer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226520 91177308-0d34-0410-b5e6-96231b3b80d8
Add `MDNode::replaceWithUniqued()` and `MDNode::replaceWithDistinct()`,
which mutate temporary nodes to become uniqued or distinct. On uniquing
collisions, the unique version is returned and the node is deleted.
This takes advantage of temporary nodes being folded back in, and should
let me clean up some awkward logic in `MapMetadata()`.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226510 91177308-0d34-0410-b5e6-96231b3b80d8
Change `MDTuple::getTemporary()` and `MDLocation::getTemporary()` to
return (effectively) `std::unique_ptr<T, MDNode::deleteTemporary>`, and
clean up call sites. (For now, `DIBuilder` call sites just call
`release()` immediately.)
There's an accompanying change in each of clang and polly to use the new
API.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226504 91177308-0d34-0410-b5e6-96231b3b80d8
Remove `MDNodeFwdDecl` (as promised in r226481). Aside from API
changes, there's no real functionality change here.
`MDNode::getTemporary()` now forwards to `MDTuple::getTemporary()`,
which returns a tuple with `isTemporary()` equal to true.
The main point is that we can now add temporaries of other `MDNode`
subclasses, needed for PR22235 (I introduced `MDNodeFwdDecl` in the
first place because I didn't recognize this need, and thought they were
only needed to handle forward references).
A few things left out of (or highlighted by) this commit:
- I've had to remove the (few) uses of `std::unique_ptr<>` to deal
with temporaries, since the destructor is no longer public.
`getTemporary()` should probably return the equivalent of
`std::unique_ptr<T, MDNode::deleteTemporary>`.
- `MDLocation::getTemporary()` doesn't exist yet (worse, it actually
does exist, but does the wrong thing: `MDNode::getTemporary()` is
inherited and returns an `MDTuple`).
- `MDNode` now only has one subclass, `UniquableMDNode`, and the
distinction between them is actually somewhat confusing.
I'll fix those up next.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226501 91177308-0d34-0410-b5e6-96231b3b80d8
Merge `getDistinct()`'s implementation with those of `get()` and
`getIfExists()` for both `MDTuple` and `MDLocation`. This will make it
easier to scale to supporting temporaries.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226497 91177308-0d34-0410-b5e6-96231b3b80d8
