It is meant to be used to record modules @imported by the current
compile unit, so a debugger an import the same modules to replicate this
environment before dropping into the expression evaluator.
DIModule is a sibling to DINamespace and behaves quite similarly.
In addition to the name of the module it also records the module
configuration details that are necessary to uniquely identify the module.
This includes the configuration macros (e.g., -DNDEBUG), the include path
where the module.map file is to be found, and the isysroot.
The idea is that the backend will turn this into a DW_TAG_module.
http://reviews.llvm.org/D9614
rdar://problem/20965932
llvm-svn: 241017
Allow callers of `Value::print()` and `Metadata::print()` to pass in a
`ModuleSlotTracker`. This allows them to pay only once for calculating
module-level slots (such as Metadata).
This is related to PR23865, where there was a huge cost for
`MachineFunction::print()`. Although I don't have a *particular* user
in mind for this new code, I have hit big slowdowns before when running
`opt -debug`, and I think this will be useful. Going forward, if
someone hits a big slowdown with `print()` statements, they can create a
`ModuleSlotTracker` and send it through. Similarly, adding support to
`Value::dump()` and `Metadata::dump()` should be trivial.
I added unit tests to be sure the `print()` functions actually behave
the same way with and without the slot tracker.
llvm-svn: 240867
so DWARF skeleton CUs can be expression in IR. A skeleton CU is a
(typically empty) DW_TAG_compile_unit that has a DW_AT_(GNU)_dwo_name and
a DW_AT_(GNU)_dwo_id attribute. It is used to refer to external debug info.
This is a prerequisite for clang module debugging as discussed in
http://lists.cs.uiuc.edu/pipermail/cfe-dev/2014-November/040076.html.
In order to refer to external types stored in split DWARF (dwo) objects,
such as clang modules, we need to emit skeleton CUs, which identify the
dwarf object (i.e., the clang module) by filename (the SplitDebugFilename)
and a hash value, the dwo_id.
This patch only contains the IR changes. The idea is that a CUs with a
non-zero dwo_id field will be emitted together with a DW_AT_GNU_dwo_name
and DW_AT_GNU_dwo_id attribute.
http://reviews.llvm.org/D9488
rdar://problem/20091852
llvm-svn: 237949
Summary:
This adds three Function methods to handle function entry counts:
setEntryCount() and getEntryCount().
Entry counts are stored under the MD_prof metadata node with the name
"function_entry_count". They are unsigned 64 bit values set by profilers
(instrumentation and sample profiler changes coming up).
Added documentation for new profile metadata and tests.
Reviewers: dexonsmith, bogner
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9628
llvm-svn: 237260
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
Support up to 2^16 arguments to a function. If we do hit the limit,
assert out rather than restarting at 0 as we've done historically.
This fixes PR23332. A clang test will follow.
llvm-svn: 235955
Add a verifier check that only functions with bodies have metadata
attachments. This should help catch bugs in frontends and
transformation passes. Part of PR23340.
llvm-svn: 235784
Add IR support for `Metadata` attachments. Assembly and bitcode support
will follow shortly, but for now we just have unit tests. This is part
of PR23340.
llvm-svn: 235783
PR23080 is almost finished. With this commit, there's no consequential
API in `DIDescriptor` and its subclasses. What's left?
- Default-constructed to `nullptr`.
- Handy `const_cast<>` (constructed from `const`, but accessors are
non-`const`).
I think the safe way to catch those is to delete the classes and fix
compile errors. That'll be my next step, after I delete the `DITypeRef`
(etc.) wrapper around `MDTypeRef`.
llvm-svn: 235069
Remove 'inlinedAt:' from MDLocalVariable. Besides saving some memory
(variables with it seem to be single largest `Metadata` contributer to
memory usage right now in -g -flto builds), this stops optimization and
backend passes from having to change local variables.
The 'inlinedAt:' field was used by the backend in two ways:
1. To tell the backend whether and into what a variable was inlined.
2. To create a unique id for each inlined variable.
Instead, rely on the 'inlinedAt:' field of the intrinsic's `!dbg`
attachment, and change the DWARF backend to use a typedef called
`InlinedVariable` which is `std::pair<MDLocalVariable*, MDLocation*>`.
This `DebugLoc` is already passed reliably through the backend (as
verified by r234021).
This commit removes the check from r234021, but I added a new check
(that will survive) in r235048, and changed the `DIBuilder` API in
r235041 to require a `!dbg` attachment whose 'scope:` is in the same
`MDSubprogram` as the variable's.
If this breaks your out-of-tree testcases, perhaps the script I used
(mdlocalvariable-drop-inlinedat.sh) will help; I'll attach it to PR22778
in a moment.
llvm-svn: 235050
Change `MDSubprogram::getFunction()` and
`MDGlobalVariable::getConstant()` to return a `Constant`. Previously,
both returned `ConstantAsMetadata`.
llvm-svn: 234699
Use `MDTypeRef` (etc.) in the new debug info hierarchy rather than raw
`Metadata *` pointers.
I rolled in a change to `DIBuilder` that looks unrelated: take `DIType`
instead of `DITypeRef` as type arguments when creating variables.
However, this was the simplest way to use `MDTypeRef` within the
functions, and didn't require any cleanups from callers in clang (since
they were all passing in `DIType`s anyway, relying on their implicit
conversions to `DITypeRef`).
llvm-svn: 234197
replaceWithUniquedUnresolved
replaceWithUniquedUnresolvedChangedOperand
=>
replaceWithUniquedResolvingOperand
replaceWithUniquedChangingOperand
I find the new names less confusing; they're also more accurate. Sorry
for the churn.
llvm-svn: 233759
Uniqued nodes have more complete registration with
`ReplaceableMetadataImpl` so that they can update themselves when
operands change. Fix a bug where `MDNode::replaceWithUniqued()` wasn't
enabling these callbacks.
The two most obvious ways missing callbacks causes problems is that
auto-resolution fails and re-uniquing (on changed operands) just doesn't
happen. I've added tests for both -- in both cases, I confirmed that
the final check was failing before the fix.
rdar://problem/20365935
llvm-svn: 233751
Add operand checks for `MDLexicalBlock` and `MDLexicalBlockFile`. Like
`MDLocalVariable` and `MDLocation`, these nodes always require a scope.
There was no test bitrot to fix here (just updated the serialization
tests in test/Assembler/mdlexicalblock.ll).
llvm-svn: 233561
Check operands of `MDSubprogram`s in the verifier, and update the
accessors and factory functions to use more specific types.
There were a lot of broken testcases, which I fixed in r233466. If you
have out-of-tree tests for debug info, you probably need similar changes
to the ones I made there.
llvm-svn: 233559
Add verify checks for `MDType` subclasses and for `MDCompileUnit`.
These new checks don't yet incorporate everything from `Verify()`, but
at least they sanity check the operands. Also downcast accessors as
possible.
A lot of these accessors can't be downcast as far as we'd like because
of arrays of typed objects (stored in a generic `MDTuple`) and
`MDString`-based type references. Eventually I'll port over `DIRef<>`
and `DITypedArray<>` from `DebugInfo.h` to clean those up as well.
Updated bitrotted testcases separately in r233415 and r233443 to reduce
churn on the off-chance this needs to be reverted.
llvm-svn: 233446
Check fields from `MDLocalVariable` and `MDGlobalVariable` and change
the accessors to downcast to the right types. `getType()` still returns
`Metadata*` since it could be an `MDString`-based reference.
Since local variables require non-null scopes, I also updated `LLParser`
to require a `scope:` field.
A number of testcases had grown bitrot and started failing with this
patch; I committed them separately in r233349. If I just broke your
out-of-tree testcases, you're probably hitting similar problems (so have
a look there).
llvm-svn: 233389
Check accessors of `MDLocation`, and change them to `cast<>` down to the
right types. Also add type-safe factory functions.
All the callers that handle broken code need to use the new versions of
the accessors (`getRawScope()` instead of `getScope()`) that still
return `Metadata*`. This is also necessary for things like
`MDNodeKeyImpl<MDLocation>` (in LLVMContextImpl.h) that need to unique
the nodes when their operands might still be forward references of the
wrong type.
In the `Value` hierarchy, consumers that handle broken code use
`getOperand()` directly. However, debug info nodes have a ton of
operands, and their order (even their existence) isn't stable yet. It's
safer and more maintainable to add an explicit "raw" accessor on the
class itself.
llvm-svn: 233322
Replumb the `AsmWriter` so that `Metadata::print()` is generally useful.
(Similarly change `Metadata::printAsOperand()`.)
- `SlotTracker` now has a mode where all metadata will be correctly
numbered when initializing a `Module`. Normally, `Metadata` only
referenced from within `Function`s gets numbered when the `Function`
is incorporated.
- `Metadata::print()` and `Metadata::printAsOperand()` (and
`Metadata::dump()`) now take an optional `Module` argument. When
provided, `SlotTracker` is initialized with the new mode, and the
numbering will be complete and consistent for all calls to `print()`.
- `Value::print()` uses the new `SlotTracker` mode when printing
intrinsics with `MDNode` operands, `MetadataAsValue` operands, or the
bodies of functions. Thus, metadata numbering will be consistent
between calls to `Metadata::print()` and `Value::print()`.
- `Metadata::print()` (and `Metadata::dump()`) now print the full
definition of `MDNode`s:
!5 = !{!6, !"abc", !7}
This matches behaviour for `Value::print()`, which includes the name
of instructions.
- Updated call sites in `Verifier` to call `print()` instead of
`printAsOperand()`.
All this, so that `Verifier` can print out useful failure messages that
involve `Metadata` for PR22777.
Note that `Metadata::printAsOperand()` previously took an optional
`bool` and `Module` operand. The former was cargo-culted from
`Value::printAsOperand()` and wasn't doing anything useful. The latter
didn't give consistent results (without the new `SlotTracker` mode).
llvm-svn: 232275
Add the final bits of API that `DIBuilder` needs before the new nodes
can be moved into place.
- Add `MDType::clone()` and `MDType::setFlags()` to support
`DIBuilder::createTypeWithFlags()`.
- Add `MDBasicType::get()` overload that just requires a tag and a
name, as a convenience for `DIBuilder::createUnspecifiedType()`.
- Add `MDLocalVariable::withInline()` and
`MDLocalVariable::withoutInline()` to support
`llvm::createInlinedVariable()` and
`llvm::cleanseInlinedVariable()`.
(Somehow these got lost inside the "move into place" patch I'm about to
commit -- better to commit separately!)
llvm-svn: 231079
Fix `MDScope::getFile()` so that it correctly returns a valid `MDFile`
even when it's an instance of `MDFile`. This logic is necessary because
of r230057. I'm working on moving the new hierarchy into place
out-of-tree (on track to commit Monday morning, BTW), and this was
exposed by a few failing tests.
llvm-svn: 230871
Remove a newline from `AssemblyWriter::printMDNodeBody()`, and add one
to `AssemblyWriter::writeMDNode()`. NFCI for assembly output.
However, this drops an inconsistent newline from `Metadata::print()`
when `this` is an `MDNode`. Now the newline added by `Metadata::dump()`
won't look so verbose.
llvm-svn: 230565
When trying to match the current schema with the new debug info
hierarchy, I downgraded `SizeInBits`, `AlignInBits` and `OffsetInBits`
to 32-bits (oops!). Caught this while testing my upgrade script to move
the hierarchy into place. Bump it back up to 64-bits and update tests.
llvm-svn: 229933
Add missing `nullptr` from `MDSubroutineType`'s operands for
`MDCompositeTypeBase::getIdentifier()` (and add tests for all the other
unused fields). This highlights just how crazy it is that
`MDSubroutineType` inherits from `MDCompositeTypeBase`.
llvm-svn: 229926
Follow-up to r229740, which removed `DITemplate*::getContext()` after my
upgrade script revealed that scopes are always `nullptr` for template
parameters. This is the other shoe: drop `scope:` from
`MDTemplateParameter` and its two subclasses. (Note: a bitcode upgrade
would be pointless, since the hierarchy hasn't been moved into place.)
llvm-svn: 229791
It turns out that `count: -1` is a special value indicating an empty
array, such as `Values` in:
struct T {
unsigned Count;
int Values[];
};
Handle it.
llvm-svn: 229769
Add `replaceElements()`, `replaceVTableHolder()`, and
`replaceTemplateParams()` to `MDCompositeTypeBase`. Included an
assertion in `replaceElements()` to match the one in
`DICompositeType::replaceArrays()`.
llvm-svn: 229744
Add missing specialized node overloads for `MDNode::clone()` (they were
on most of the node types already, but missing from the others).
`MDNode::clone()` returns `TempMDNode` (`std::unique_ptr<MDNode,...>`),
while `TempMDSubrange::clone()` (for example) returns the more
convenient `TempMDSubrange` (`std::unique_ptr<TempMDSubrange,...>`).
llvm-svn: 229579
Port `DIExpression::Operand` over to `MDExpression::ExprOperand`. The
logic is needed directly in `MDExpression` to support printing in
assembly.
llvm-svn: 229002
Add new API for converting temporaries that may self-reference.
Self-referencing nodes are not allowed to be uniqued, so sending them
into `replaceWithUniqued()` is dangerous (and this commit adds
assertions that prevent it).
`replaceWithPermanent()` has similar semantics to `get()` followed by
calls to `replaceOperandWith()`. In particular, if there's a
self-reference, it returns a distinct node; otherwise, it returns a
uniqued one. Like `replaceWithUniqued()` and `replaceWithDistinct()`
(well, it calls out to them) it mutates the temporary node in place if
possible, only calling `replaceAllUsesWith()` on a uniquing collision.
llvm-svn: 228726
I noticed this fields were never used in r228607, but I neglected to
propagate that into `MDTemplateParameter` until now. This really should
have been done before commit in r228640; sorry for the churn.
llvm-svn: 228652
Add specialized debug info metadata nodes that match the `DIDescriptor`
wrappers (used by `DIBuilder`) closely. Assembly and bitcode support to
follow soon (it'll mostly just be obvious), but this sketches in today's
schema. This is the first big commit (well, the only *big* one aside
from the testcase changes that'll come when I move this into place) for
PR22464.
I've marked a bunch of obvious changes as `TODO`s in the source; I plan
to make those changes promptly after this hierarchy is moved underneath
`DIDescriptor`, but for now I'm aiming mostly to match the status quo.
llvm-svn: 228640
Remove unnecessary restriction of 24-bits for line numbers in
`MDLocation`.
The rest of the debug info schema (with the exception of local
variables) uses 32-bits for line numbers. As I introduce the
specialized nodes, it makes sense to canonicalize on one size or the
other.
llvm-svn: 228455
Move debug-info-centred `Metadata` subclasses into their own
header/source file. A couple of private template functions are needed
from both `Metadata.cpp` and `DebugInfoMetadata.cpp`, so I've moved them
to `lib/IR/MetadataImpl.h`.
llvm-svn: 227835
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.
llvm-svn: 226874
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.)
llvm-svn: 226866
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.
llvm-svn: 226529
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()`.
llvm-svn: 226510
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.
llvm-svn: 226504
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.
llvm-svn: 226501
Add an `LLVMContext &` to `ReplaceableMetadataImpl`, create a class that
either holds a reference to an `LLVMContext` or owns a
`ReplaceableMetadataImpl`, and use the new class in `MDNode`.
- This saves a pointer in `UniquableMDNode` at the cost of a pointer
in `ValueAsMetadata` (which didn't used to store the `LLVMContext`).
There are far more of the former.
- Unifies RAUW support between `MDNodeFwdDecl` (which is going away,
see r226481) and `UniquableMDNode`.
llvm-svn: 226484
Change `MDNode::isDistinct()` to only apply to 'distinct' nodes (not
temporaries), and introduce `MDNode::isUniqued()` and
`MDNode::isTemporary()` for the other two possibilities.
llvm-svn: 226482
Happened pretty commonly during `LLVMContext` teardown when `clang -g`
hit an error. This fixes the use-after-free. Next I'll clean up
teardown so that it's not RAUW'ing when metadata-tracked values are
deleted (only really causes a problem if the graph is mid-construction
when teardown starts, but it's still unnecessary work).
llvm-svn: 226029
utils/sort_includes.py.
I clearly haven't done this in a while, so more changed than usual. This
even uncovered a missing include from the InstrProf library that I've
added. No functionality changed here, just mechanical cleanup of the
include order.
llvm-svn: 225974
Add a new subclass of `UniquableMDNode`, `MDLocation`. This will be the
IR version of `DebugLoc` and `DILocation`. The goal is to rename this
to `DILocation` once the IR classes supersede the `DI`-prefixed
wrappers.
This isn't used anywhere yet. Part of PR21433.
llvm-svn: 225824
This adds back the testcase from r225738, and adds to it. Looks like we
need both sides for now (the assertion was incorrect both ways, and
although it seemed reasonable (when written correctly) it wasn't
particularly important).
llvm-svn: 225745
This reverts commit r225738. Maybe the assertion is just plain wrong,
but this version fails on WAY more bots. I'll make sure both ways work
in a follow-up but I want to get bots green in the meantime.
llvm-svn: 225742
Allow distinct `MDNode`s to be explicitly created. There's no way (yet)
of representing their distinctness in assembly/bitcode, however, so this
still isn't first-class.
Part of PR22111.
llvm-svn: 225406
Add API to indicate whether an `MDNode` is distinct. A distinct node is
not stored in the MDNode uniquing tables, and will never be returned by
`MDNode::get()`.
Although distinct nodes are only currently created by uniquing
collisions (when operands change), PR22111 will allow these nodes to be
explicitly created.
llvm-svn: 225401
Now that `LLVMContextImpl` can call `MDNode::dropAllReferences()` to
prevent teardown madness, stop dropping uniquing just because an operand
drops to null.
Part of PR21532.
llvm-svn: 225223
It's horrible to inspect `MDNode`s in a debugger. All of their operands
that are `MDNode`s get dumped as `<badref>`, since we can't assign
metadata slots in the context of a `Metadata::dump()`. (Why not? Why
not assign numbers lazily? Because then each time you called `dump()`,
a given `MDNode` could have a different lazily assigned number.)
Fortunately, the C memory model gives us perfectly good identifiers for
`MDNode`. Add pointer addresses to the dumps, transforming this:
(lldb) e N->dump()
!{i32 662302, i32 26, <badref>, null}
(lldb) e ((MDNode*)N->getOperand(2))->dump()
!{i32 4, !"foo"}
into:
(lldb) e N->dump()
!{i32 662302, i32 26, <0x100706ee0>, null}
(lldb) e ((MDNode*)0x100706ee0)->dump()
!{i32 4, !"foo"}
and this:
(lldb) e N->dump()
0x101200248 = !{<badref>, <badref>, <badref>, <badref>, <badref>}
(lldb) e N->getOperand(0)
(const llvm::MDOperand) $0 = {
MD = 0x00000001012004e0
}
(lldb) e N->getOperand(1)
(const llvm::MDOperand) $1 = {
MD = 0x00000001012004e0
}
(lldb) e N->getOperand(2)
(const llvm::MDOperand) $2 = {
MD = 0x0000000101200058
}
(lldb) e N->getOperand(3)
(const llvm::MDOperand) $3 = {
MD = 0x00000001012004e0
}
(lldb) e N->getOperand(4)
(const llvm::MDOperand) $4 = {
MD = 0x0000000101200058
}
(lldb) e ((MDNode*)0x00000001012004e0)->dump()
!{}
(lldb) e ((MDNode*)0x0000000101200058)->dump()
!{null}
into:
(lldb) e N->dump()
!{<0x1012004e0>, <0x1012004e0>, <0x101200058>, <0x1012004e0>, <0x101200058>}
(lldb) e ((MDNode*)0x1012004e0)->dump()
!{}
(lldb) e ((MDNode*)0x101200058)->dump()
!{null}
llvm-svn: 224325
The RAUW support in `Metadata` supports going to `nullptr` specifically
to handle values being deleted, causing `ValueAsMetadata` to be deleted.
Fix the case where the reference is from a `TrackingMDRef` (as opposed
to an `MDOperand` or a `MetadataAsValue`).
This is surprisingly rare -- metadata tracked by `TrackingMDRef` going
to null -- but it came up in an openSUSE bootstrap during inlining. The
tracking ref was held by the `ValueMap` because it was referencing a
local, the basic block containing the local became dead after it had
been merged in, and when the local was deleted, the tracking ref
asserted in an `isa`.
llvm-svn: 224146
Split `Metadata` away from the `Value` class hierarchy, as part of
PR21532. Assembly and bitcode changes are in the wings, but this is the
bulk of the change for the IR C++ API.
I have a follow-up patch prepared for `clang`. If this breaks other
sub-projects, I apologize in advance :(. Help me compile it on Darwin
I'll try to fix it. FWIW, the errors should be easy to fix, so it may
be simpler to just fix it yourself.
This breaks the build for all metadata-related code that's out-of-tree.
Rest assured the transition is mechanical and the compiler should catch
almost all of the problems.
Here's a quick guide for updating your code:
- `Metadata` is the root of a class hierarchy with three main classes:
`MDNode`, `MDString`, and `ValueAsMetadata`. It is distinct from
the `Value` class hierarchy. It is typeless -- i.e., instances do
*not* have a `Type`.
- `MDNode`'s operands are all `Metadata *` (instead of `Value *`).
- `TrackingVH<MDNode>` and `WeakVH` referring to metadata can be
replaced with `TrackingMDNodeRef` and `TrackingMDRef`, respectively.
If you're referring solely to resolved `MDNode`s -- post graph
construction -- just use `MDNode*`.
- `MDNode` (and the rest of `Metadata`) have only limited support for
`replaceAllUsesWith()`.
As long as an `MDNode` is pointing at a forward declaration -- the
result of `MDNode::getTemporary()` -- it maintains a side map of its
uses and can RAUW itself. Once the forward declarations are fully
resolved RAUW support is dropped on the ground. This means that
uniquing collisions on changing operands cause nodes to become
"distinct". (This already happened fairly commonly, whenever an
operand went to null.)
If you're constructing complex (non self-reference) `MDNode` cycles,
you need to call `MDNode::resolveCycles()` on each node (or on a
top-level node that somehow references all of the nodes). Also,
don't do that. Metadata cycles (and the RAUW machinery needed to
construct them) are expensive.
- An `MDNode` can only refer to a `Constant` through a bridge called
`ConstantAsMetadata` (one of the subclasses of `ValueAsMetadata`).
As a side effect, accessing an operand of an `MDNode` that is known
to be, e.g., `ConstantInt`, takes three steps: first, cast from
`Metadata` to `ConstantAsMetadata`; second, extract the `Constant`;
third, cast down to `ConstantInt`.
The eventual goal is to introduce `MDInt`/`MDFloat`/etc. and have
metadata schema owners transition away from using `Constant`s when
the type isn't important (and they don't care about referring to
`GlobalValue`s).
In the meantime, I've added transitional API to the `mdconst`
namespace that matches semantics with the old code, in order to
avoid adding the error-prone three-step equivalent to every call
site. If your old code was:
MDNode *N = foo();
bar(isa <ConstantInt>(N->getOperand(0)));
baz(cast <ConstantInt>(N->getOperand(1)));
bak(cast_or_null <ConstantInt>(N->getOperand(2)));
bat(dyn_cast <ConstantInt>(N->getOperand(3)));
bay(dyn_cast_or_null<ConstantInt>(N->getOperand(4)));
you can trivially match its semantics with:
MDNode *N = foo();
bar(mdconst::hasa <ConstantInt>(N->getOperand(0)));
baz(mdconst::extract <ConstantInt>(N->getOperand(1)));
bak(mdconst::extract_or_null <ConstantInt>(N->getOperand(2)));
bat(mdconst::dyn_extract <ConstantInt>(N->getOperand(3)));
bay(mdconst::dyn_extract_or_null<ConstantInt>(N->getOperand(4)));
and when you transition your metadata schema to `MDInt`:
MDNode *N = foo();
bar(isa <MDInt>(N->getOperand(0)));
baz(cast <MDInt>(N->getOperand(1)));
bak(cast_or_null <MDInt>(N->getOperand(2)));
bat(dyn_cast <MDInt>(N->getOperand(3)));
bay(dyn_cast_or_null<MDInt>(N->getOperand(4)));
- A `CallInst` -- specifically, intrinsic instructions -- can refer to
metadata through a bridge called `MetadataAsValue`. This is a
subclass of `Value` where `getType()->isMetadataTy()`.
`MetadataAsValue` is the *only* class that can legally refer to a
`LocalAsMetadata`, which is a bridged form of non-`Constant` values
like `Argument` and `Instruction`. It can also refer to any other
`Metadata` subclass.
(I'll break all your testcases in a follow-up commit, when I propagate
this change to assembly.)
llvm-svn: 223802
It doesn't make sense to unique self-referencing nodes. Drop uniquing
for them.
Note that `MDNode::intersect()` occasionally returns self-referencing
nodes. Previously these would be returned by `MDNode::get()`. I'm not
convinced this was intended behaviour -- to me it seems it should return
a node whose only operand is the self-reference -- but I don't know much
about alias scopes so I'm preserving it for now.
This is part of PR21532.
llvm-svn: 223618
Apparently `MDNode` uniquing used to be optional. I suppose the
configure flag must have disappeared at some point. Change the test so
it actually tests uniquing, and remove the check for
`ENABLE_MDNODE_UNIQUING`.
llvm-svn: 223617
Move the test for this class into the IR unittests as well.
This uncovers that ValueMap too is in the IR library. Ironically, the
unittest for ValueMap is useless in the Support library (honestly, so
was the ValueHandle test) and so it already lives in the IR unittests.
Mmmm, tasty layering.
llvm-svn: 202821
Adrian Prantl