We can't read a deduced return type until we are sure that the types referred
to by it are not in the middle of being loaded. So defer all reading of such
deduced return types until the end of the recursive deserialization step.
Also, when we load a function type that has a deduced return type, update all
other redeclarations of the function to have that deduced return type.
llvm-svn: 338798
Summary:
Clang emits error when implicit modules was relocated from the
first build directory. However this was biting our usecase where we copy
the contents of build directory to another directory in order to
distribute.
Differential Revision: https://reviews.llvm.org/D49852
llvm-svn: 338503
Consider:
1) Generate PCH with -fmodules and -fmodule-map-file
2) Use PCH with -fmodules and the same -fmodule-map-file
If we don't load -fmodule-map-file content before including PCHs,
the modules that are dependencies in PCHs cannot get loaded,
since there's no matching module map file when reading back the AST.
rdar://problem/40852867
Differential Revision: https://reviews.llvm.org/D48685
llvm-svn: 337447
Summary:
Reproducer and errors:
https://bugs.llvm.org/show_bug.cgi?id=37878
lookupModule was falling back to loadSubdirectoryModuleMaps when it couldn't
find ModuleName in (proper) search paths. This was causing iteration over all
files in the search path subdirectories for example "/usr/include/foobar" in
bugzilla case.
Users don't expect Clang to load modulemaps in subdirectories implicitly, and
also the disk access is not cheap.
if (AllowExtraModuleMapSearch) true with ObjC with @import ModuleName.
Reviewers: rsmith, aprantl, bruno
Subscribers: cfe-commits, teemperor, v.g.vassilev
Differential Revision: https://reviews.llvm.org/D48367
llvm-svn: 337430
This patch improves traceability of duplicated header files which end
up in multiple pcms.
Differential Revision: https://reviews.llvm.org/D47118
llvm-svn: 337353
Summary:
Reproducer and errors:
https://bugs.llvm.org/show_bug.cgi?id=37878
lookupModule was falling back to loadSubdirectoryModuleMaps when it couldn't
find ModuleName in (proper) search paths. This was causing iteration over all
files in the search path subdirectories for example "/usr/include/foobar" in
bugzilla case.
Users don't expect Clang to load modulemaps in subdirectories implicitly, and
also the disk access is not cheap.
if (AllowExtraModuleMapSearch) true with ObjC with @import ModuleName.
Reviewers: rsmith, aprantl, bruno
Subscribers: cfe-commits, teemperor, v.g.vassilev
Differential Revision: https://reviews.llvm.org/D48367
llvm-svn: 336660
Functions that are a sub-Decl of a record were hashed differently than other
functions. This change keeps the AddFunctionDecl function and the hash of
records now calls this function. In addition, AddFunctionDecl has an option
to perform a hash as if the body was absent, which is required for some
checks after loading modules. Additional logic prevents multiple error
message from being printed.
llvm-svn: 336632
merged function definitions; also merge functions with deduced return
types.
This seems like two independent fixes, but unfortunately they are hard
to separate because it's challenging to reliably test either one of them
without also testing the other.
A complication arises with deduced return type support: we need the type
of the function in order to know how to merge it, but we can't load the
actual type of the function because it might reference an entity
declared within the function (and we need to have already merged the
function to correctly merge that entity, which we would need to do to
determine if the function types match). So we instead compare the
declared function type when merging functions, and defer loading the
actual type of a function with a deduced type until we've finished
loading and merging the function.
This reverts r336175, reinstating r336021, with one change (for PR38015):
we look at the TypeSourceInfo of the first-so-far declaration of each
function when considering whether to merge two functions. This works
around a problem where the calling convention in the TypeSourceInfo for
subsequent redeclarations may not match if it was implicitly adjusted.
llvm-svn: 336240
This caused test failures in 32-bit builds (PR38015).
> merged function definitions; also merge functions with deduced return
> types.
>
> This seems like two independent fixes, but unfortunately they are hard
> to separate because it's challenging to reliably test either one of them
> without also testing the other.
>
> A complication arises with deduced return type support: we need the type
> of the function in order to know how to merge it, but we can't load the
> actual type of the function because it might reference an entity
> declared within the function (and we need to have already merged the
> function to correctly merge that entity, which we would need to do to
> determine if the function types match). So we instead compare the
> declared function type when merging functions, and defer loading the
> actual type of a function with a deduced type until we've finished
> loading and merging the function.
llvm-svn: 336175
Not doing so causes the AST writter to assert since the decl in question
never gets emitted. This is fine when modules is not used, but otherwise
we need to serialize something other than garbage.
rdar://problem/39844933
Differential Revision: https://reviews.llvm.org/D47297
llvm-svn: 336031
merged function definitions; also merge functions with deduced return
types.
This seems like two independent fixes, but unfortunately they are hard
to separate because it's challenging to reliably test either one of them
without also testing the other.
A complication arises with deduced return type support: we need the type
of the function in order to know how to merge it, but we can't load the
actual type of the function because it might reference an entity
declared within the function (and we need to have already merged the
function to correctly merge that entity, which we would need to do to
determine if the function types match). So we instead compare the
declared function type when merging functions, and defer loading the
actual type of a function with a deduced type until we've finished
loading and merging the function.
llvm-svn: 336021
ODRHash aims to provide Cross-TU stable hashing. Making clang::Type pointer
part of the hash connects (remotely) the ODRHash with the TU-specific
::Profile hasher.
r332281 exposed the issue by changing the way the ASTContext different
elaborated types if there is an owning tag. In that case, ODRHash stores two
different types in its TypeMap which yields false ODR violation in modules.
The current state of implementation shouldn't need the TypeMap concept
anymore. Rip it out.
Differential Revision: https://reviews.llvm.org/D48524
llvm-svn: 335853
checks across module boundaries. This was causing us to load constructor
definitions for all consumers of a module with a pending check.
(In one case we saw ~7% of total frontend time spent loading
constructors for this check.)
llvm-svn: 335807
declaration of the function that ends up in the primary definition of
the class.
... at least for class templates. This is necessary for us to be able to
track when an inline friend function has a definition that needs to be
(lazily) instantiated.
llvm-svn: 335805
Using @import in framework headers inhibit the use of such headers
when not using modules, this is specially bad for headers that end
up in the SDK (or any other system framework). Add a warning to give
users some indication that this is discouraged.
rdar://problem/39192894
llvm-svn: 335780
Framework vendors usually layout their framework headers in the
following way:
Foo.framework/Headers -> "public" headers
Foo.framework/PrivateHeader -> "private" headers
Since both headers in both directories can be found with #import
<Foo/some-header.h>, it's easy to make mistakes and include headers in
Foo.framework/PrivateHeader from headers in Foo.framework/Headers, which
usually configures a layering violation on Darwin ecosystems. One of the
problem this causes is dep cycles when modules are used, since it's very
common for "private" modules to include from the "public" ones; adding
an edge the other way around will trigger cycles.
Add a warning to catch those cases such that:
./A.framework/Headers/A.h:1:10: warning: public framework header includes private framework header 'A/APriv.h'
#include <A/APriv.h>
^
rdar://problem/38712182
llvm-svn: 335542
Introduce -Wquoted-include-in-framework-header, which should fire a warning
whenever a quote include appears in a framework header and suggest a fix-it.
For instance, for header A.h added in the tests, this is how the warning looks
like:
./A.framework/Headers/A.h:2:10: warning: double-quoted include "A0.h" in framework header, expected angle-bracketed instead [-Wquoted-include-in-framework-header]
#include "A0.h"
^~~~~~
<A/A0.h>
./A.framework/Headers/A.h:3:10: warning: double-quoted include "B.h" in framework header, expected angle-bracketed instead [-Wquoted-include-in-framework-header]
#include "B.h"
^~~~~
<B.h>
This helps users to prevent frameworks from using local headers when in fact
they should be targetting system level ones.
The warning is off by default.
Differential Revision: https://reviews.llvm.org/D47157
rdar://problem/37077034
llvm-svn: 335375
Header maps are binary files used by Xcode, which are used to map
header names or paths to other locations. Clang has support for
those since its inception, but there's not a lot of header map
testing around.
Since it's a binary format, testing becomes pretty much brittle
and its hard to even know what's inside if you don't have the
appropriate tools.
Add a python based tool that allows creating and dumping header
maps based on a json description of those. While here, rewrite
tests to use the tool and remove the binary files from the tree.
This tool was initially written by Daniel Dunbar.
Thanks to Stella Stamenova for helping make this work on Windows.
Differential Revision: https://reviews.llvm.org/D46485
rdar://problem/39994722
llvm-svn: 335295
Introduce -Wquoted-include-in-framework-header, which should fire a warning
whenever a quote include appears in a framework header and suggest a fix-it.
For instance, for header A.h added in the tests, this is how the warning looks
like:
./A.framework/Headers/A.h:2:10: warning: double-quoted include "A0.h" in framework header, expected angle-bracketed instead [-Wquoted-include-in-framework-header]
#include "A0.h"
^~~~~~
<A/A0.h>
./A.framework/Headers/A.h:3:10: warning: double-quoted include "B.h" in framework header, expected angle-bracketed instead [-Wquoted-include-in-framework-header]
#include "B.h"
^~~~~
<B.h>
This helps users to prevent frameworks from using local headers when in fact
they should be targetting system level ones.
The warning is off by default.
Differential Revision: https://reviews.llvm.org/D47157
rdar://problem/37077034
llvm-svn: 335184
Header maps are binary files used by Xcode, which are used to map
header names or paths to other locations. Clang has support for
those since its inception, but there's not a lot of header map
testing around.
Since it's a binary format, testing becomes pretty much brittle
and its hard to even know what's inside if you don't have the
appropriate tools.
Add a python based tool that allows creating and dumping header
maps based on a json description of those. While here, rewrite
tests to use the tool and remove the binary files from the tree.
This tool was initially written by Daniel Dunbar.
Differential Revision: https://reviews.llvm.org/D46485
rdar://problem/39994722
llvm-svn: 335177
When in the context of suggestion the fix-it from .Private to _Private
for private modules, trim off the 'explicit' and add 'framework' when
appropriate.
rdar://problem/41030554
llvm-svn: 334859
Previous, if no Decl's were checked, visibility was set to false. Switch it
so that in cases of no Decl's, return true. These are the Decl's after being
filtered. Also remove an unreachable return statement since it is directly
after another return statement.
llvm-svn: 334160
Avoid storing information for definitions since those can be out-of-line and
vary between modules even when the declarations are the same.
llvm-svn: 334151
When a module declaration for a framework lacks the 'framework'
qualifier, the listed headers aren't found (because there's no
trigger for the special framework style path lookup) and the module
is silently not built. This leads to frameworks not being modularized
by accident, which is pretty bad.
Add a warning and suggest the user to add the 'framework' qualifier
when we can prove that it's the case.
rdar://problem/39193062
llvm-svn: 333718
Unless the user uses -Wno-module-file-config-mismatch (or -Wno-error=...),
allow the AST reader to produce errors describing the nature of the config
mismatch.
llvm-svn: 333220
FunctionProtoType.
We previously re-evaluated the expression each time we wanted to know whether
the type is noexcept or not. We now evaluate the expression exactly once.
This is not quite "no functional change": it fixes a crasher bug during AST
deserialization where we would try to evaluate the noexcept specification in a
situation where we have not deserialized sufficient portions of the AST to
permit such evaluation.
llvm-svn: 331428
A @import targeting a top level module from a private module map file
(@import Foo_Private), would fail if there's any submodule declaration
around (module Foo.SomeSub) in the same private module map.
This happens because compileModuleImpl, when building Foo_Private, will
start with the private module map and will not parse the public one,
which leads to unsuccessful parsing of Foo.SomeSub, since top level Foo
was never parsed.
Declaring other submodules in the private module map is not common and
should usually be avoided, but it shouldn't fail to build. Canonicalize
compileModuleImpl to always look at the public module first, so that all
necessary information is available when parsing the private one.
rdar://problem/39822328
llvm-svn: 331322
Support for ObjC/C ODR-like semantics with structural equivalence
checking was added back in r306918. There enums are handled and also
checked for structural equivalence. However, at use time of
EnumConstantDecl, support was missing for preventing ambiguous
name lookup.
Add the missing bits for properly merging EnumConstantDecl.
rdar://problem/38374569
llvm-svn: 331232
During deserialization clang is currently missing the merging of
protocols into the canonical interface for the class extension.
This merging only currently happens during parsing and should also
be considered during deserialization.
rdar://problem/38724303
llvm-svn: 331063
Without these comments, by "luck" the contents of SomeKit's SKWidget.h
are precisely the same as SomeKitCore's SomeKitCore.h. This can create
havoc if anything canonicalizes on the inode and your filesystem assigns
a common inode to files with identical file content. Alternatively, if
your build system uses symlinks into a content-addressed-storage (as
Google's does), you end up with these files being symlinks to the same
file.
The end result is that Clang deduplicates them internally, and then
believes that the SomeKit framework includes the SomeKitCore.h header,
and does not include the SKWidget.h in SomeKit. This in turn results in
warnings in this test and eventually errors as Clang becomes confused
because the umbrella header for SomeKitCore has already been included
into another framework's module (SomeKit). Yay.
If anyone has a better idea about how to avoid this, I'm all ears.
Nothing other than causing the file content to change worked for me.
llvm-svn: 330184
framework module SomeKitCore {
...
export_as SomeKit
}
Given the module above, while generting autolink information during
codegen, clang should to emit '-framework SomeKitCore' only if SomeKit
was not imported in the relevant TU, otherwise it should use '-framework
SomeKit' instead.
rdar://problem/38269782
llvm-svn: 330152
Summary:
This patch extend getTargetDefines and implement handleTargetFeatures
and hasFeature. and define corresponding marco for those features.
Reviewers: asb, apazos, eli.friedman
Differential Revision: https://reviews.llvm.org/D44727
Patch by Kito Cheng.
llvm-svn: 329278
commit 519b97132a4c960e8dedbfe4290d86970d92e995
Author: Richard Trieu <rtrieu@google.com>
Date: Sat Mar 24 00:52:44 2018 +0000
[ODRHash] Support pointer and reference types.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@328404 91177308-0d34-0410-b5e6-96231b3b80d8
As it's breaking some tests. I've communicated with Richard offline about testcases.
llvm-svn: 329001
During reading C++ definition data for lambda we can access
CXXRecordDecl representing lambda before we finished reading the
definition data. This can happen by reading a captured variable which is
VarDecl, then reading its decl context which is CXXMethodDecl `operator()`,
then trying to merge redeclarable methods and accessing
enclosing CXXRecordDecl. The call stack looks roughly like
VisitCXXRecordDecl
ReadCXXRecordDefinition
VisitVarDecl
VisitCXXMethodDecl
mergeRedeclarable
getPrimaryContextForMerging
If we add fake definition data at this point, later we'll hit the assertion
Assertion failed: (!DD.IsLambda && !MergeDD.IsLambda && "faked up lambda definition?"), function MergeDefinitionData, file clang/lib/Serialization/ASTReaderDecl.cpp, line 1675.
The fix is to assign definition data before reading it. Fixes PR32556.
rdar://problem/37461072
Reviewers: rsmith, bruno
Reviewed By: rsmith
Subscribers: cfe-commits, jkorous-apple, aprantl
Differential Revision: https://reviews.llvm.org/D43494
llvm-svn: 328153
When skipping building the module for a private framework module,
LangOpts.CurrentModule isn't enough for implict modules builds; for
instance, in case a private module is built while building a public one,
LangOpts.CurrentModule doesn't reflect the -fmodule-name being passed
down, but instead the module name which triggered the build.
Store the actual -fmodule-name in LangOpts.ModuleName and actually
check a name was provided during compiler invocation in order to
skip building the private module.
rdar://problem/38434694
llvm-svn: 328053
This patch uses the infrastructure added in r326307 for enabling
non-trivial fields to be declared in C structs to allow __weak fields in
C structs in ARC.
This recommits r327206, which was reverted because it caused
module-enabled builders to fail. I discovered that the
CXXRecordDecl::CanPassInRegisters flag wasn't being set correctly in
some cases after I moved it to RecordDecl.
Thanks to Eric Liu for helping me investigate the bug.
rdar://problem/33599681
https://reviews.llvm.org/D44095
llvm-svn: 327870
All use declarations need to be directly placed in the top-level module
anyway, knowing the submodule doesn't really help. The header that has
the offending #include can easily be seen in the diagnostics source
location.
Review: https://reviews.llvm.org/D43673
llvm-svn: 326023
The tests that failed on a windows host have been fixed.
Original message:
Start setting dso_local for COFF.
With this there are still some GVs where we don't set dso_local
because setGVProperties is never called. I intend to fix that in
followup commits. This is just the bare minimum to teach
shouldAssumeDSOLocal what it should do for COFF.
llvm-svn: 325940
Assume Foo.framework with two module maps and two modules Foo and
Foo_Private.
Framework authors need to skip building both Foo and Foo_Private when
using -fmodule-name=Foo, since both are part of the framework and used
interchangeably during compilation.
rdar://problem/37500098
llvm-svn: 325305
diagnostic settings using _Pragma within a macro.
The AST writer had previously been assuming that all diagnostic state
transitions would occur within a FileID corresponding to a file. When a
diagnostic state change occured within a macro, it was unable to form a
location for that state change and would instead corrupt the diagnostic state
of the "root" node (and thus that of the main compilation).
Also introduce a "#pragma clang __debug diag_mapping" debugging utility
that I added to track this issue down.
llvm-svn: 324695
This patch:
* fixes an incorrect sign-extension of unsigned values, when emitting
debug info metadata for enumerators
* the enumerators metadata is created with a flag, which determines
interpretation of the value bits (signed or unsigned)
* the enumerations metadata contains the underlying integer type and a
flag, indicating whether this is a C++ "fixed enum"
Differential Revision: https://reviews.llvm.org/D42736
llvm-svn: 324490
Using a BlockDecl in a default member initializer causes it to be attached to
CXXMethodDecl without its access specifier being set. This prevents a crash
where getAccess is called on this BlockDecl, since that method expects any
Decl in CXXRecord scope to have an access specifier.
llvm-svn: 322984
Summary:
Upstream LLVM is changing the the prototypes of the @llvm.memcpy/memmove/memset
intrinsics. This change updates the Clang tests for this change.
The @llvm.memcpy/memmove/memset intrinsics currently have an explicit argument
which is required to be a constant integer. It represents the alignment of the
dest (and source), and so must be the minimum of the actual alignment of the
two.
This change removes the alignment argument in favour of placing the alignment
attribute on the source and destination pointers of the memory intrinsic call.
For example, code which used to read:
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 100, i32 4, i1 false)
will now read
call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 4 %dest, i8* align 4 %src, i32 100, i1 false)
At this time the source and destination alignments must be the same (Step 1).
Step 2 of the change, to be landed shortly, will relax that contraint and allow
the source and destination to have different alignments.
llvm-svn: 322964
In certain combinations of templated classes and friend functions, the body
of friend functions does not get propagated along with function signature.
Exclude friend functions for hashing to avoid this case.
llvm-svn: 322350
Any hashing for methods should be able to compile this test case without
emitting an error. Since the class and method come from the same header from
each module, there should be no messages about ODR violations.
llvm-svn: 321924
Attempting to recompute it are doomed to fail because the IDNS of a declaration
is not necessarily preserved across serialization and deserialization (in turn
because whether a friend declaration is visible depends on whether some prior
non-friend declaration exists).
llvm-svn: 321921
redecl chain for an imported declaration, make sure to check the IDNS of prior
imported decls.
Otherwise we can end up finding an invisible friend declaration and incorrectly
believing that it should be visible.
llvm-svn: 321916
When modules come from module map files explicitly specified by
-fmodule-map-file= arguments, allow those to override/shadow modules
with the same name that are found implicitly by header search. If such a
module is looked up by name (e.g. @import), we will always find the one
from -fmodule-map-file. If we try to use a shadowed module by including
one of its headers report an error.
This enables developers to force use of a specific copy of their module
to be used if there are multiple copies that would otherwise be visible,
for example if they develop modules that are installed in the default
search paths.
Patch originally by Ben Langmuir,
http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20151116/143425.html
Based on cfe-dev discussion:
http://lists.llvm.org/pipermail/cfe-dev/2015-November/046164.html
Differential Revision: https://reviews.llvm.org/D31269
rdar://problem/23612102
llvm-svn: 321855
When modules come from module map files explicitly specified by
-fmodule-map-file= arguments, allow those to override/shadow modules
with the same name that are found implicitly by header search. If such a
module is looked up by name (e.g. @import), we will always find the one
from -fmodule-map-file. If we try to use a shadowed module by including
one of its headers report an error.
This enables developers to force use of a specific copy of their module
to be used if there are multiple copies that would otherwise be visible,
for example if they develop modules that are installed in the default
search paths.
Patch originally by Ben Langmuir,
http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20151116/143425.html
Based on cfe-dev discussion:
http://lists.llvm.org/pipermail/cfe-dev/2015-November/046164.html
Differential Revision: https://reviews.llvm.org/D31269
rdar://problem/23612102
llvm-svn: 321781
Summary:
cp -a is neither part of POSIX nor the LSB. The nearest equivalent under
POSIX is cp -RPp; however, cp -R is sufficient for the intended purpose.
test/Modules/crash-vfs-headermaps.m is not updated since it requires
system-darwin anyway.
Reviewers: bruno
Reviewed By: bruno
Subscribers: bruno, rcraik, cfe-commits
Differential Revision: https://reviews.llvm.org/D41545
llvm-svn: 321778
When a type is only used as a template parameter and that type is the
only type imported from another #include'd module, no skeleton CU for
that module is generated, so a consumer doesn't know where to find the
type definition. By emitting an import declaration, we can force a
skeleton CU to be generated for each imported module.
rdar://problem/36266156
llvm-svn: 321754
Extend the hashing to functions, which allows detection of function definition
mismatches across modules. This is a re-commit of r320230.
llvm-svn: 321395
In case `@import Foo.Private` fails because the submodule doesn't exist,
look for `Foo_Private` (if available) and build/load that module
instead. In that process emit a warning and tell the user about the
assumption.
The intention here is to assist all existing private modules owners
(in ObjC and Swift) to migrate to the new `Foo_Private` syntax.
rdar://problem/36023940
llvm-svn: 321342
We used to advertise private modules to be declared as submodules
(Foo.Private). This has proven to not scale well since private headers
might carry several dependencies, introducing unwanted content into the
main module and often causing dep cycles.
Change the canonical way to name it to Foo_Private, forcing private
modules as top level ones, and provide warnings under -Wprivate-module
to suggest fixes for other private naming. Update documentation to
reflect that.
rdar://problem/31173501
llvm-svn: 321337
An unscoped enumeration used as template argument, should not have any
qualified information about its enclosing scope, as its visibility is
global.
In the case of scoped enumerations, they must include information
about their enclosing scope.
Patch by Carlos Alberto Enciso!
Differential Revision: https://reviews.llvm.org/D39239
llvm-svn: 321312
When mixing PCH and Implicit Modules, missing a header search path
can lead to the implicit built PCM to complaint about not finding its
matching module map.
Instead of adding more magic to implicit modules engine, add a note to
help the user add the appropriate path.
rdar://problem/33388847
llvm-svn: 318503
Add a mix of postive and negative tests to check that wrong Decls won't be
flagged in the diagnostic. Split the check everything test and moved the
pieces closer to where the related tests are.
llvm-svn: 317394
Since they'll likely (not always - if the address is taken, etc) be
inlined away, even at -O0, separately provided weak definitions are
likely to be unused so skip all of that.
llvm-svn: 317279
Consistent with various workarounds in the backwards compatible modules
that allow static functions in headers to exist, be deduplicated to some
degree, and not generally fail right out of the gate... do the same with
modular codegen as there are enough cases (including in libstdc++ and in
LLVM itself - though I cleaned up the easy ones) that it's worth
supporting as a migration/backcompat step.
Simply create a separate, internal linkage function in each object that
needs it. If an available_externally/modularized function references a
static function, but the modularized function is eventually dropped and
not inlined, the static function will be dropped as unreferenced.
llvm-svn: 317274
for instantiating its definition.
We model the 'inline'ness as being instantiated with the static data member in
order to track whether the declaration has become a definition yet.
llvm-svn: 317147
They might have different visibility, and thus discarding all but one of them
can result in rejecting valid code. Also fix name lookup to cope with multiple
using-directives being found that denote the same namespace, where some are not
visible -- don't cache an "already visited" state for a using-directive that we
didn't visit because it was hidden.
llvm-svn: 316965
This is breaking a build of https://github.com/abseil/abseil-cpp and so
likely not really NFC. Also reverted subsequent r314956/7.
I'll forward reproduction instructions to Richard.
llvm-svn: 315439