This relands r250831 after some fixes to shrink the ParentMap overall
with one addtional tweak: nodes with pointer identity (e.g. Decl* and
friends) can be store more efficiently so I put them in a separate map.
All other nodes (so far only TypeLoc and NNSLoc) go in a different map
keyed on DynTypedNode. This further uglifies the code but significantly
reduces memory overhead.
Overall this change still make ParentMap significantly larger but it's
nowhere as bad as before. I see about 25 MB over baseline (pre-r251008)
on X86ISelLowering.cpp. If this becomes an issue we could consider
splitting the maps further as DynTypedNode is still larger (32 bytes)
than a single TypeLoc (16 bytes) but I didn't want to introduce even
more complexity now.
Differential Revision: http://reviews.llvm.org/D14011
llvm-svn: 251101
Putting DynTypedNode in the ParentMap bloats its memory foot print.
Before the void* key had 8 bytes, now we're at 40 bytes per key which
can mean multiple gigabytes increase for large ASTs and this count
doesn't even include all the added TypeLoc nodes. Revert until I come
up with a better data structure.
This reverts commit r250831.
llvm-svn: 250889
Firstly this changes the type of parent map to be keyed on DynTypedNode to
simplify the following changes. This comes with a DenseMapInfo for
DynTypedNode, which is a bit incomplete still and will probably only work
for parentmap right now.
Then the RecursiveASTVisitor in ASTContext is updated and finally
ASTMatchers hasParent and hasAncestor learn about the new functionality.
Now ParentMap is only missing TemplateArgumentLocs and CXXCtorInitializers.
Differential Revision: http://reviews.llvm.org/D13897
llvm-svn: 250831
Summary: It breaks the build for the ASTMatchers
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D13893
llvm-svn: 250827
AllCallbacks is currently only used to call onStartOfTranslationUnit and
onEndOfTranslationUnit on them. In this (and any other scenario I can
come up with), it is important (or at least better) not to have
duplicates in this container. E.g. currently onEndOfTranslationUnit is
called repeatedly on the same callback for every matcher that is
registered with it.
llvm-svn: 249598
While this may seem like a lot of unrelated changes, they all relate back to fixing HasDeclarationMatcher.
This now allows us to write a matcher like:
varDecl(hasType(namedDecl(hasName("Foo"))))
that matches code using typedefs, objc interfaces, template type parameters, injected class names, or unresolved using typenames.
llvm-svn: 247404
Individual matchers might not be convertible to each other's kind, but
they might still all be convertible to the target kind.
All the callers already know the target kind, so just pass it down.
llvm-svn: 242534
It's better not to rely on the diagnostics engine to pretty print the
argument to decltype. Instead, exercise the functionality in
DeclPrinterTest.
llvm-svn: 239197
If the type isn't trivially moveable emplace can skip a potentially
expensive move. It also saves a couple of characters.
Call sites were found with the ASTMatcher + some semi-automated cleanup.
memberCallExpr(
argumentCountIs(1), callee(methodDecl(hasName("push_back"))),
on(hasType(recordDecl(has(namedDecl(hasName("emplace_back")))))),
hasArgument(0, bindTemporaryExpr(
hasType(recordDecl(hasNonTrivialDestructor())),
has(constructExpr()))),
unless(isInTemplateInstantiation()))
No functional change intended.
llvm-svn: 238601
In a static build the dependency is picked up implictly, but not in a shared
library build. This is needed for the new ObjC matchers that reference Selector.
llvm-svn: 232055
Add some matchers for Objective-C selectors and messages to
ASTMatchers.h. Minor mods to ASTMatchersTest.h to allow test files with
".m" extension in addition to ".cpp". New tests added to
ASTMatchersTest.c.
Patch by Dean Sutherland.
llvm-svn: 232051
Summary:
Speed up the variadic matchers by removing one indirect call.
Making the function pointer a template arguments allows the compiler to
inline the call instead of doing an runtime call by pointer.
Also, optimize the allOf() case to avoid redundant kind checks.
This speeds up our clang-tidy benchmark by ~2%
Reviewers: klimek
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D6424
llvm-svn: 223029
Change to original: ifndef out tests in Windows due to /-separated
paths.
Summary:
Often one is only interested in matches within the main-file or matches
that are not within a system-header, for which this patch adds
isInMainFile and isInSystemFile. They take no arguments and narrow down
the matches.
The isInFileMatchingName is mainly thought for interactive
clang-query-sessions, to make a matcher more specific without restarting
the session with the files you are interested in for that moment. It
takes a string that will be used as regular-expression to match the
filename of where the matched node is expanded.
Patch by Hendrik von Prince.
llvm-svn: 222765
Summary:
Filter the toplevel matchers by kind.
Decl and Stmt matchers are tied to a specific node kind and trying to
match incompatible nodes is a waste.
Precalculate a filtered list of matchers that have a chance of matching
the node and ignore the rest.
Speeds up our clang-tidy benchmark by ~10%
Reviewers: klimek
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D6361
llvm-svn: 222688
Summary:
Often one is only interested in matches within the main-file or matches
that are not within a system-header, for which this patch adds
isInMainFile and isInSystemFile. They take no arguments and narrow down
the matches.
The isInFileMatchingName is mainly thought for interactive
clang-query-sessions, to make a matcher more specific without restarting
the session with the files you are interested in for that moment. It
takes a string that will be used as regular-expression to match the
filename of where the matched node is expanded.
Patch by Hendrik von Prince.
llvm-svn: 222646
Summary:
Replace variadic operator function pointer with an enum value.
Hiding the implementation of the variadic matcher will allow to specialize them for the operation performed.
In particular, it will allow for a more efficient allOf() matcher.
Reviewers: klimek
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D6293
llvm-svn: 222432
Summary:
The generic variadic matcher is faster (one less virtual function call
per match) and doesn't require template instantiations which reduces
compile time and binary size.
Registry.cpp.o generates ~14% less symbols and compiles ~7.5% faster.
The change also speeds up our clang-tidy benchmark by ~2%.
Reviewers: klimek
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D6278
llvm-svn: 222131
Summary:
Speed up clang-tidy when profiling in on.
It makes profiling runs twice as fast by reusing the time samples between the
different actions.
It also joins together the sampling of different matchers of the same check.
Reviewers: alexfh
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D5972
llvm-svn: 220682
Summary:
Add support for profiling the matchers used.
This will be connected with clang-tidy to generate a report to determine
and debug slow checks.
Reviewers: alexfh
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D5911
llvm-svn: 220418
Summary:
Fix code to follow the "Don’t use else after a return" rule.
This is a followup from rL219792.
Reviewers: alexfh
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D5826
llvm-svn: 219939
Summary:
Speed up hasName() matcher by skipping the expensive generation of the
fully qualified name unless we need it.
In the common case of matching an unqualified name, we don't need to
generate the full name. We might not even need to copy any string at
all.
This change speeds up our clang-tidy benchmark by ~10%
Reviewers: klimek
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D5776
llvm-svn: 219792
Fix order of evaluation bug in DynTypedMatcher::constructVariadic().
If it evaluates right-to-left, the vector gets moved before we read the
kind from it.
llvm-svn: 219624
Summary:
Change r219118 fixed the bug for anyOf and eachOf, but it is still
present for unless.
The variadic wrapper doesn't have enough information to know how to
restrict the type. Different operators handle restrict failures in
different ways.
Reviewers: klimek
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D5731
llvm-svn: 219622
Summary:
There was an assumption that there were no matchers that were overloaded
on matchers and other types of arguments.
This assumption was broken recently with the addition of new matcher
overloads.
Fixes http://llvm.org/PR21226
Reviewers: pcc
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D5711
llvm-svn: 219450
Summary:
Remove unnecessary wrapping for the 0 and 1 matcher cases of
makeAllOfComposite(). We don't need a variadic wrapper for those cases.
Refactor TrueMatcher to take advandage of the new conversions between
DynTypedMatcher and Matcher<T>. Also, make it a singleton.
This change improves our clang-tidy related benchmarks by ~12%.
Reviewers: klimek
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D5675
llvm-svn: 219431
Summary:
DynTypedMatcher::constructVariadic() where the restrict kind of the
different matchers are not related causes the matcher to have a "None"
restrict kind. This causes false negatives for anyOf and eachOf.
Change the logic to get a common ancestor if there is one.
Also added regression tests that fail without the fix.
Reviewers: klimek
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D5580
llvm-svn: 219118
Summary:
This change introduces DynMatcherInterface and changes the internal
representation of DynTypedMatcher and Matcher<T> to use a generic
interface instead.
It removes unnecessary indirections and virtual function calls when
converting matchers by implicit and dynamic casts.
DynTypedMatcher now remembers the stricter type in the chain of casts
and checks it before calling into DynMatcherInterface.
This change improves our clang-tidy related benchmark by ~14%.
Also, it opens the door for more optimizations of this kind that are
coming in future changes.
As a side effect of removing these template instantiations, it also
speeds up compilation of Dynamic/Registry.cpp by ~17% and reduces the
number of
symbols generated by ~30%.
Reviewers: klimek
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D5542
llvm-svn: 218769
MSC17, aka VS2012, cannot compile it.
clang/include/clang/ASTMatchers/ASTMatchersInternal.h(387) : error C4519: default template arguments are only allowed on a class template
clang/include/clang/ASTMatchers/ASTMatchersInternal.h(443) : see reference to class template instantiation 'clang::ast_matchers::internal::Matcher<T>' being compiled
llvm-svn: 218648
Summary:
This change introduces DynMatcherInterface and changes the internal
representation of DynTypedMatcher and Matcher<T> to use a generic
interface instead.
It removes unnecessary indirections and virtual function calls when
converting matchers by implicit and dynamic casts.
DynTypedMatcher now remembers the stricter type in the chain of casts
and checks it before calling into DynMatcherInterface.
This change improves our clang-tidy related benchmark by ~14%.
Also, it opens the door for more optimizations of this kind that are
coming in future changes.
As a side effect of removing these template instantiations, it also
speeds up compilation of Dynamic/Registry.cpp by ~17% and reduces the number of
symbols generated by ~30%.
Reviewers: klimek
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D5485
llvm-svn: 218616
Summary:
Separate the matchers by type and statically dispatch to the right list.
For any node type that we support, it reduces the number of matchers we
run it through.
For node types we do not support, it makes match() a noop.
This change improves our clang-tidy related benchmark by ~30%.
Reviewers: klimek
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D5197
llvm-svn: 217274
Summary:
Refactor VariantMatcher::MatcherOps to reduce the amount of generated code.
- Make some code type agnostic and move it to the cpp file.
- Return a DynTypedMatcher instead of storing the object in MatcherOps.
This change reduces the number of symbols generated in Registry.cpp by
~19%, the object byte size by ~17% and the compilation time (in non-release mode) by ~20%.
Reviewers: klimek
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D5124
llvm-svn: 217152
This is hoisted from clang-tidy where it's used everywhere. The implementation
is not particularly efficient right now, but there is no easy fix for that.
Differential Revision: http://reviews.llvm.org/D5085
llvm-svn: 217029
But don't move if all we do is clearing the thing. The move method is too large
to be inlined and performs a ton of unnecessary checking when the RHS is empty.
No functionality change.
llvm-svn: 216723
Summary:
This includes:
- Passing a Sema to completeExpression to allow for named values in the
expression.
- Passing a map of names to values to the parser.
- Update the Sema interface to include completion for matchers.
- Change the parser to use the Sema for completion, instead of going
directly to Registry.
Reviewers: pcc
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D3509
llvm-svn: 215472
After post-commit review and community discussion, this seems like a
reasonable direction to continue, making ownership semantics explicit in
the source using the type system.
llvm-svn: 215323
If nodes without memoization data (e.g. TypeLocs) are bound to specific
names, that effectively prevents memoization as those elements cannot be
compared effectively. If it is tried anyway, this can lead to an assert
as demonstrated in the new test.
In the long term, the better solution will be to enable DynTypedNodes
without memoization data. For now, simply skip memoization instead.
llvm-svn: 213751
This reverts commit r213307.
Reverting to have some on-list discussion/confirmation about the ongoing
direction of smart pointer usage in the LLVM project.
llvm-svn: 213325
(after fixing a bug in MultiplexConsumer I noticed the ownership of the
nested consumers was implemented with raw pointers - so this fixes
that... and follows the source back to its origin pushing unique_ptr
ownership up through there too)
llvm-svn: 213307
Summary:
Add hasLocalStorage/hasGlobalStorage matchers for VarDecl nodes.
Update the doc. Also add them to the dynamic registry.
Reviewers: klimek
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D4034
llvm-svn: 210278
Summary: Add support for named values in the parser.
Reviewers: pcc
CC: cfe-commits, klimek
Differential Revision: http://llvm-reviews.chandlerc.com/D3276
llvm-svn: 206176
Summary:
Add support for named values in the parser.
This allows injection of arbitrary constants using a custom Sema object.
Completions are not supported right now.
Will be used by clang_query to support the 'let' command.
Usage example:
clang_query> let unique_ptr recordDecl(hasName("unique_ptr"))
clang_query> match varDecl(hasType(unique_ptr))
Reviewers: klimek, pcc
CC: cfe-commits, klimek
Differential Revision: http://llvm-reviews.chandlerc.com/D3229
llvm-svn: 205419
Summary:
Add loc() to the dynamic registry.
Other fixes:
- Fix the polymorphic variant value to accept an exact match, even if
there are other possible conversions.
- Fix specifiesTypeLoc() to not crash on an empty
NestedNameSpecifierLoc.
Reviewers: klimek
CC: cfe-commits, klimek
Differential Revision: http://llvm-reviews.chandlerc.com/D2928
llvm-svn: 203467
This does;
- clang_tablegen() adds each tblgen'd target to global property CLANG_TABLEGEN_TARGETS as list.
- List of targets is added to LLVM_COMMON_DEPENDS.
- all clang libraries and targets depend on generated headers.
You might wonder this would be regression, but in fact, this is little loss.
- Almost all of clang libraries depend on tblgen'd files and clang-tblgen.
- clang-tblgen may cause short stall-out but doesn't cause unconditional rebuild.
- Each library's dependencies to tblgen'd files might vary along headers' structure.
It made hard to track and update *really optimal* dependencies.
Each dependency to intrinsics_gen and ClangSACheckers is left as DEPENDS.
llvm-svn: 201842
hasAnyTemplateArgument, and (out of necessity) an isExpr matcher.
Also updates the TemplateArgument doxygen to reflect reality for
non-canonical template arguments.
Differential Revision: http://llvm-reviews.chandlerc.com/D2810
llvm-svn: 201804
This function returns a list of completions for a given expression and
completion position.
Differential Revision: http://llvm-reviews.chandlerc.com/D2261
llvm-svn: 200497
This returns a list of valid (and useful) completions for a context (a list
of outer matchers), ordered by decreasing relevance then alphabetically. It
will be used by the matcher parser to implement completion.
Differential Revision: http://llvm-reviews.chandlerc.com/D2210
llvm-svn: 199950
encodes the canonical rules for LLVM's style. I noticed this had drifted
quite a bit when cleaning up LLVM, so wanted to clean up Clang as well.
llvm-svn: 198686
The new names will be more appropriate when the objects are taught to return
type information for the code completer.
Differential Revision: http://llvm-reviews.chandlerc.com/D2208
llvm-svn: 195539
Summary: Add support for the 'unless' matcher in the dynamic layer.
Reviewers: klimek
CC: cfe-commits, revane, klimek
Differential Revision: http://llvm-reviews.chandlerc.com/D2247
llvm-svn: 195466
Summary:
Add partial support for the hasDeclaration() matcher in the dynamic layer.
This matcher has some special logic to allow any type that has a getDecl() method. We do not support this right now.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1889
llvm-svn: 195013
Summary: This resubmits r193100, plus a fix for a breakage with MSVC.
Reviewers: klimek, rnk
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D2005
llvm-svn: 193613
Summary:
Refactor DynTypedMatcher into a value type class, just like Matcher<T>.
This simplifies its usage and removes the virtual hierarchy from Matcher<T>.
It also enables planned changes to replace MatcherInteface<T>.
Too many instantiaions of this class hierarchy has been causing Registry.cpp.o to bloat in size and number of symbols.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1661
llvm-svn: 193100
Summary:
Reduce the number of symbols by changing how templates are instantiated per function bound in the registry.
This change reduces the number of sections in Registry.cpp.o by a little over 10%.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1557
llvm-svn: 189676
Summary:
Add support for eachOf/allOf/anyOf variadic matchers in the dynamic layer.
These function require some late binding behavior for the type conversions, thus changes in VariadicValue's MatcherList.
Second try. This time with a fix for C++11 builds.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1536
llvm-svn: 189500
Summary:
Add support for eachOf/allOf/anyOf variadic matchers in the dynamic layer.
These function require some late binding behavior for the type conversions, thus changes in VariadicValue's MatcherList.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1531
llvm-svn: 189362
Summary:
Rewrite eachOf/allOf/anyOf to use a variadic operator, instead of hand-written calls to Polymorphic matchers.
This simplifies their definition and future changes to add them to the dynamic registry.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1427
llvm-svn: 189357
Summary:
Refactor VariantMatcher to use an interface underneath.
It supports "Single" and "Polymorphic". Will support more in the future.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1446
llvm-svn: 189032
Summary:
Refactor ArgumentAdaptativeMatcher matchers to remove the template from their declaration.
This facilitates dynamic registration. Change the registry code to use the regular overload resolution mechanism for adaptative matchers.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1402
llvm-svn: 188560
Summary:
Refactor "MatcherList" into "VariantMatcher" and abstract the notion of a list of matchers for the polymorphic case.
This work is to support future changes needed for eachOf/allOf/anyOf matchers. We will add a new type on VariantMatcher.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1365
llvm-svn: 188272
- pull out function to drill to the CXXRecordDecl from the type,
to allow recursive resolution
- make the analysis more robust by rather skipping values we don't
understand
llvm-svn: 187676
In TUs with large classes, a matcher like
methodDecl(ofClass(recordDecl(has(varDecl()))))
(finding all member functions of classes with static variables)
becomes unbearably slow otherwise.
llvm-svn: 187115
Summary:
Add support for Adaptative matchers on the dynamic registry.
Each adaptative matcher is created with a function template. We instantiate the function N times, one for each possible From type and apply the techniques used on argument overloaded and polymorphic matchers to add them to the registry.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1201
llvm-svn: 187044
Summary:
Add support for overloaded matchers.
This composes with other features, like supporting polymorphic matchers.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1188
llvm-svn: 186836
Summary:
Add printToStream*(llvm::raw_ostream&) methods to Diagnostics, and reimplement everything based on streams instead of concatenating strings.
Also, fix some functions to start with lowercase to match the style guide.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1187
llvm-svn: 186715
Summary:
Change how error messages are constructed and stored in Diagnostics.
Separate the notion of 'context' when recursing down in the parser and actual errors.
This will simplify adding some new features, like argument overloading and error recovery.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1168
llvm-svn: 186602
Summary:
Continue adding more matchers to the dynamic registry.
This time, we add TemplateArgument matchers.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1166
llvm-svn: 186514
Summary: Now that CXXCtorInitializer is already supported in ASTNodeKind, add CXXCtorInitializer matchers to the dynamic matcher registry.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1158
llvm-svn: 186508
As every match call can recursively call back into the memoized match
via a nested traversal matcher (for example:
stmt(hasAncestor(stmt(hasDescendant(stmt(hasDescendant(stmt()))))))),
and every memoization step might clear the cache, we must not store
iterators into the result cache when calling match on a submatcher.
llvm-svn: 186411
Summary:
Fixup the type traversal macros/matchers to specify the supported types.
Make the marshallers a little more generic to support any variadic function.
Update the doc script.
Reviewers: klimek
CC: cfe-commits, revane
Differential Revision: http://llvm-reviews.chandlerc.com/D1023
llvm-svn: 186340
Pulled out the cache clearing in the case of descendant matching, too,
for consistency, also it is not technically needed there.
FIXME: Make cache size configurable and add unit test.
llvm-svn: 185820
- Added conversion routines and checks in Matcher<T> that take a DynTypedMatcher.
- Added type information on the error messages for the marshallers.
- Allows future work on Polymorphic/overloaded matchers. We should be
able to disambiguate at runtime and choose the appropriate overload.
llvm-svn: 184429
This is in preparation for the backwards references to bound
nodes, which will expose a lot more about how matches occur. Main
changes:
- instead of building the tree of bound nodes, we build a "set" of bound
nodes and explode all possible match combinations while running
through the matchers; this will allow us to also implement matchers
that filter down the current set of matches, like "equalsBoundNode"
- take the set of bound nodes at the start of the match into
consideration when doing memoization; as part of that, reevaluated
that memoization gives us benefits that are large enough (it still
does - the effect on common match patterns is up to an order of
magnitude)
- reset the bound nodes when a node does not match, thus never leaking
information from partial sub-matcher matches for failing matchers
Effects:
- we can now correctly "explode" combinatorial matches, for example:
allOf(forEachDescendant(...bind("a")),
forEachDescendant(...bind("b"))) will now trigger matches for all
combinations of matching "a" and "b"s.
- we now never expose bound nodes from partial matches in matchers that
did not match in the end - this fixes a long-standing issue
FIXMEs:
- rename BoundNodesTreeBuilder to BoundNodesBuilder or
BoundNodesSetBuilder, as we don't build a tree any more; this is out
of scope for this change, though
- we're seeing some performance regressions (around 10%), but I expect
some performance tuning will get that back, and it's easily worth
the increase in expressiveness for now
llvm-svn: 184313
Aaron Ballman