Summary:
A *.cpp file header in LLDB (and in LLDB) should like this:
```
//===-- TestUtilities.cpp -------------------------------------------------===//
```
However in LLDB most of our source files have arbitrary changes to this format and
these changes are spreading through LLDB as folks usually just use the existing
source files as templates for their new files (most notably the unnecessary
editor language indicator `-*- C++ -*-` is spreading and in every review
someone is pointing out that this is wrong, resulting in people pointing out that this
is done in the same way in other files).
This patch removes most of these inconsistencies including the editor language indicators,
all the different missing/additional '-' characters, files that center the file name, missing
trailing `===//` (mostly caused by clang-format breaking the line).
Reviewers: aprantl, espindola, jfb, shafik, JDevlieghere
Reviewed By: JDevlieghere
Subscribers: dexonsmith, wuzish, emaste, sdardis, nemanjai, kbarton, MaskRay, atanasyan, arphaman, jfb, abidh, jsji, JDevlieghere, usaxena95, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D73258
Summary:
This commit renames ClangASTContext to TypeSystemClang to better reflect what this class is actually supposed to do
(implement the TypeSystem interface for Clang). It also gets rid of the very confusing situation that we have both a
`clang::ASTContext` and a `ClangASTContext` in clang (which sometimes causes Clang people to think I'm fiddling
with Clang's ASTContext when I'm actually just doing LLDB work).
I also have plans to potentially have multiple clang::ASTContext instances associated with one ClangASTContext so
the ASTContext naming will then become even more confusing to people.
Reviewers: #lldb, aprantl, shafik, clayborg, labath, JDevlieghere, davide, espindola, jdoerfert, xiaobai
Reviewed By: clayborg, labath, xiaobai
Subscribers: wuzish, emaste, nemanjai, mgorny, kbarton, MaskRay, arphaman, jfb, usaxena95, jingham, xiaobai, abidh, JDevlieghere, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D72684
Summary:
Our DWARFUnit was automatically forwarding the requests to the split
unit when looking for a DIE by offset. llvm::DWARFUnit does not do that,
and is not likely to start doing it any time soon.
This patch deletes the this logic and updates the callers to request the
correct unit instead. While doing that, I've found a bit of duplicated
code for lookup up a function and block by address, so I've extracted
that into a helper function.
Reviewers: JDevlieghere, aprantl, clayborg, jdoerfert
Subscribers: lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D73112
We were creating a bunch of LineSequence objects but never deleting
them.
This fixes the leak and changes the code to use std::unique_ptr, to make
it harder to make the same mistake again.
Summary:
This code is handling debug info paths starting with /proc/self/cwd,
which is one of the mechanisms people use to obtain "relocatable" debug
info (the idea being that one starts the debugger with an appropriate
cwd and things "just work").
Instead of resolving the symlinks inside DWARFUnit, we can do the same
thing more elegantly by hooking into the existing Module path remapping
code. Since llvm::DWARFUnit does not support any similar functionality,
doing things this way is also a step towards unifying llvm and lldb
dwarf parsers.
Reviewers: JDevlieghere, aprantl, clayborg, jdoerfert
Subscribers: lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71770
Summary:
Motivation: When setting breakpoints in certain projects line sequences are frequently being inserted out of order.
Rather than inserting sequences one at a time into a sorted line table, store all the line sequences as we're building them up and sort and flatten afterwards.
Reviewers: jdoerfert, labath
Reviewed By: labath
Subscribers: teemperor, labath, mgrang, JDevlieghere, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D72909
[this re-applies c0176916a4
with the correct commit message and phabricator link]
This addresses point 1 of PR44213.
https://bugs.llvm.org/show_bug.cgi?id=44213
The DW_AT_LLVM_sysroot attribute is used for Clang module debug info,
to allow LLDB to import a Clang module from source. Currently it is
part of each DW_TAG_module, however, it is the same for all modules in
a compile unit. It is more efficient and less ambiguous to store it
once in the DW_TAG_compile_unit.
This should have no effect on DWARF consumers other than LLDB.
Differential Revision: https://reviews.llvm.org/D71732
This is a purely cosmetic change that is NFC in terms of the binary
output. I bugs me that I called the attribute DW_AT_LLVM_isysroot
since the "i" is an artifact of GCC command line option syntax
(-isysroot is in the category of -i options) and doesn't carry any
useful information otherwise.
This attribute only appears in Clang module debug info.
Differential Revision: https://reviews.llvm.org/D71722
This reverts D53469, which changed llvm's DWARF emission to emit
DW_AT_call_return_pc as a function-local offset. Such an encoding is not
compatible with post-link block re-ordering tools and isn't standards-
compliant.
In addition to reverting back to the original DW_AT_call_return_pc
encoding, teach lldb how to fix up DW_AT_call_return_pc when the address
comes from an object file pointed-to by a debug map. While doing this I
noticed that lldb's support for tail calls that cross a DSO/object file
boundary wasn't covered, so I added tests for that. This latter case
exercises the newly added return PC fixup.
The dsymutil changes in this patch were originally included in D49887:
the associated test should be sufficient to test DW_AT_call_return_pc
encoding purely on the llvm side.
Differential Revision: https://reviews.llvm.org/D72489
These are the last sections not managed by the DWARFContext object. I
also introduce separate SectionType enums for dwo section variants, as
this is necessary for proper handling of single-file split dwarf.
This patch removes the code (deep inside DWARFDebugInfoEntry) which
automagically returned the attributes of the dwo unit DIE when asking
for the attributes of the skeleton unit. This is fairly hacky, and not
consistent with how llvm DWARF parser operates.
Instead, I change the code the explicitly request (via
GetNonSkeletonUnit) the right unit to search (there were just two places
that needed this). If it turns out we need this more often, we can
create a utility function (external to DWARFUnit) for doing this.
Summary:
Our code was expecting that a single (symbol) file contains only one
kind of location lists. This is not correct (on non-apple platforms, at
least) as a file can compile units with different dwarf versions.
This patch moves the deteremination of location list flavour down to the
compile unit level, fixing this problem. I have also tried to rougly
align the code with the llvm DWARFUnit. Fully matching the API is not
possible because of how lldb's DWARFExpression lives separately from the
rest of the DWARF code, but this is at least a step in the right
direction.
Reviewers: JDevlieghere, aprantl, clayborg
Subscribers: dblaikie, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71751
This function is not very useful, as it's forcing a materialization of
the returned DIEs, and calling it is not substantially simpler than just
iterating over the DIEs manually. Delete it, and rewrite the single
caller.
Summary:
This code is handling debug info paths starting with /proc/self/cwd,
which is one of the mechanisms people use to obtain "relocatable" debug
info (the idea being that one starts the debugger with an appropriate
cwd and things "just work").
Instead of resolving the symlinks inside DWARFUnit, we can do the same
thing more elegantly by hooking into the existing Module path remapping
code. Since llvm::DWARFUnit does not support any similar functionality,
doing things this way is also a step towards unifying llvm and lldb
dwarf parsers.
Reviewers: JDevlieghere, aprantl, clayborg, jdoerfert
Subscribers: lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71770
This is a purely cosmetic change that is NFC in terms of the binary
output. I bugs me that I called the attribute DW_AT_LLVM_isysroot
since the "i" is an artifact of GCC command line option syntax
(-isysroot is in the category of -i options) and doesn't carry any
useful information otherwise.
This attribute only appears in Clang module debug info.
Differential Revision: https://reviews.llvm.org/D71722
Summary:
Fixes PR41237 - SIGSEGV on call expression evaluation when debugging clang
When linking multiple compilation units that define the same functions,
the functions is merged but their debug info is not. This ignores debug
info entries for functions in a non-executable sections; those are
functions that were definitely dropped by the linker.
Reviewers: spyffe, clayborg, jasonmolenda
Reviewed By: clayborg
Subscribers: labath, aprantl, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71487
Summary:
This adds support for DWARF5 location lists which are specified
indirectly, via an index into the debug_loclists offset table. This
includes parsing the DW_AT_loclists_base attribute which determines the
location of this offset table, and support for new form DW_FORM_loclistx
which is used in conjuction with DW_AT_location to refer to the location
lists in this way.
The code uses the llvm class to parse the offset information, and I've
also tried to structure it similarly to how the relevant llvm
functionality works.
Reviewers: JDevlieghere, aprantl, clayborg
Subscribers: lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71268
Summary:
Lldb support base address selection entries in location lists was broken
for a long time. This wasn't noticed until llvm started producing these
kinds of entries more frequently with r374600.
In r374769, I made a quick patch which added sufficient support for them
to get the test suite to pass. However, I did not fully understand how
this code operates, and so the fix was not complete. Specifically, what
was lacking was the ability to handle modules which were not loaded at
their preferred load address (for instance, due to ASLR).
Now that I better understand how this code works, I've come to the
conclusion that the current setup does not provide enough information
to correctly process these entries. In the current setup the location
lists were parameterized by two addresses:
- the distance of the function start from the start of the compile unit.
The purpose of this was to make the location ranges relative to the
start of the function.
- the actual address where the function was loaded at. With this the
function-start-relative ranges can be translated to actual memory
locations.
The reason for the two values, instead of just one (the load bias) is (I
think) MachO, where the debug info in the object files will appear to be
relative to the address zero, but the actual code it refers to
can be moved and reordered by the linker. This means that the location
lists need to be "linked" to reflect the locations in the actual linked
file.
These two bits of information were enough to correctly process location
lists which do not contain base address selection entries (and so all
entries are relative to the CU base). However, they don't work with
them because, in theory two base address can be completely unrelated (as
can happen for instace with hot/cold function splitting, where the
linker can reorder the two pars arbitrarily).
To fix that, I split the first parameter into two:
- the compile unit base address
- the function start address, as is known in the object file
The new algorithm becomes:
- the location lists are processed as they were meant to be processed.
The CU base address is used as the initial base address value. Base
address selection entries can set a new base.
- the difference between the "file" and "load" function start addresses
is used to compute the load bias. This value is added to the final
ranges to get the actual memory location.
This algorithm is correct for non-MachO debug info, as there the
location lists correctly describe the code in the final executable, and
the dynamic linker can just move the entire module, not pieces of it. It
will also be correct for MachO if the static linker preserves relative
positions of the various parts of the location lists -- I don't know
whether it actually does that, but judging by the lack of base address
selection support in dsymutil and lldb, this isn't something that has
come up in the past.
I add a test case which simulates the ASLR scenario and demonstrates
that base address selection entries now work correctly here.
Reviewers: JDevlieghere, aprantl, clayborg
Subscribers: dblaikie, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D70532
Summary:
Our rnglist support was working only for the trivial cases (one CU),
because we only ever parsed one contribution out of the debug_rnglists
section. This means we were never able to resolve range lists for the
second and subsequent units (DW_FORM_sec_offset references came out
blang, and DW_FORM_rnglistx references always used the ranges lists from
the first unit).
Since both llvm and lldb rnglist parsers are sufficiently
self-contained, and operate similarly, we can fix this problem by
switching to the llvm parser instead. Besides the changes which are due
to variations in the interface, the main thing is that now the range
list object is a member of the DWARFUnit, instead of the entire symbol
file. This ensures that each unit can get it's own private set of range
list indices, and is consistent with how llvm's DWARFUnit does it
(overall, I've tried to structure the code the same way as the llvm
version).
I've also added a test case for the two unit scenario.
Reviewers: JDevlieghere, aprantl, clayborg
Subscribers: dblaikie, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71021
Summary:
Lldb's "format-independent" debug info made use of the fact that DWARF
(<=4) did not use the file index zero, and reused the support file index
zero for storing the compile unit name.
While this provided some convenience for DWARF<=4, it meant that the PDB
plugin needed to artificially remap file indices in order to free up
index 0. Furthermore, DWARF v5 make file index 0 legal, which meant that
similar remapping would be needed in the dwarf plugin too.
What this patch does instead is remove the requirement of having the
compile unit name in the index 0. It is not that useful since the name
can always be fetched from the CompileUnit object. Remapping code in the
pdb plugin(s) has been removed or simplified.
DWARF plugin has started inserting an empty FileSpec at index 0 to
ensure the indices keep matching up (in case of DWARF<=4). For DWARF5,
we insert the file 0 from the line table.
I add a test to ensure we can correctly lookup line table entries
referencing file 0, and in particular the case where the file 0 is also
duplicated in another file entry, as this is how clang produces line
tables in some circumstances (see pr44170). Though this is probably a
bug in clang, this is not forbidden by DWARF, and lldb already has
support for that in some (but not all) cases -- this adds a test for the
code path which was not fixed in this patch.
Reviewers: clayborg, JDevlieghere, jdoerfert
Subscribers: aprantl, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D70954
Summary:
The FileSpec class is often used as a sort of a pattern -- one specifies
a bare file name to search, and we check if in matches the full file
name of an existing module (for example).
These comparisons used FileSpec::Equal, which had some support for it
(via the full=false argument), but it was not a good fit for this job.
For one, it did a symmetric comparison, which makes sense for a function
called "equal", but not for typical searches (when searching for
"/foo/bar.so", we don't want to find a module whose name is just
"bar.so"). This resulted in patterns like:
if (FileSpec::Equal(pattern, file, pattern.GetDirectory()))
which would request a "full" match only if the pattern really contained
a directory. This worked, but the intended behavior was very unobvious.
On top of that, a lot of the code wanted to handle the case of an
"empty" pattern, and treat it as matching everything. This resulted in
conditions like:
if (pattern && !FileSpec::Equal(pattern, file, pattern.GetDirectory())
which are nearly impossible to decipher.
This patch introduces a FileSpec::Match function, which does exactly
what most of FileSpec::Equal callers want, an asymmetric match between a
"pattern" FileSpec and a an actual FileSpec. Empty paterns match
everything, filename-only patterns match only the filename component.
I've tried to update all callers of FileSpec::Equal to use a simpler
interface. Those that hardcoded full=true have been changed to use
operator==. Those passing full=pattern.GetDirectory() have been changed
to use FileSpec::Match.
There was also a handful of places which hardcoded full=false. I've
changed these to use FileSpec::Match too. This is a slight change in
semantics, but it does not look like that was ever intended, and it was
more likely a result of a misunderstanding of the "proper" way to use
FileSpec::Equal.
[In an ideal world a "FileSpec" and a "FileSpec pattern" would be two
different types, but given how widespread FileSpec is, it is unlikely
we'll get there in one go. This at least provides a good starting point
by centralizing all matching behavior.]
Reviewers: teemperor, JDevlieghere, jdoerfert
Subscribers: emaste, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D70851
Summary:
CompileUnit is a complicated class. Having it be implicitly convertible
to a FileSpec makes reasoning about it even harder.
This patch replaces the inheritance by a simple member and an accessor
function. This avoid the need for casting in places where one needed to
force a CompileUnit to be treated as a FileSpec, and does not add much
verbosity elsewhere.
It also fixes a bug where we were wrongly comparing CompileUnit& and a
CompileUnit*, which compiled due to a combination of this inheritance
and the FileSpec*->FileSpec implicit constructor.
Reviewers: teemperor, JDevlieghere, jdoerfert
Subscribers: lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D70827
Split CallEdge into DirectCallEdge and IndirectCallEdge. Teach
DWARFExpression how to evaluate entry values in cases where the current
activation was created by an indirect call.
rdar://57094085
Differential Revision: https://reviews.llvm.org/D70100
This feature is mostly there to aid debugging of Clang module issues,
since the only useful actual the end-user can to is to recompile their
program.
Differential Revision: https://reviews.llvm.org/D70272
I wanted to further simplify ParseTypeFromClangModule by replacing the
hand-rolled loop with ForEachExternalModule, and then realized that
ForEachExternalModule also had the problem of visiting the same leaf
node an exponential number of times in the worst-case. This adds a set
of searched_symbol_files set to the function as well as the ability to
early-exit from it.
Differential Revision: https://reviews.llvm.org/D70215
The test was failing due to a bug in SymbolFileDWARF::FindFunctions --
the function was searching the main dwarf unit for DW_TAG_subprograms,
but the main unit is empty in case of split dwarf. The fix is simple --
search the non-skeleton unit instead.
This bug went unnoticed because this function is expensive, and so one
generally avoids calling it.
This avoids confusing them with fission-related functionality.
I also moved two accessor functions from DWARFDIE into static
functions in DWARFASTParserClang were their only use is located.
Performance issues lead to the libc++ std::function formatter to be disabled. We addressed some of those performance issues by adding caching see D67111
This PR fixes the first lookup performance by not using FindSymbolsMatchingRegExAndType(...) and instead finding the compilation unit the std::function wrapped callable should be in and then searching for the callable directly in the CU.
Differential Revision: https://reviews.llvm.org/D69913
This is basically the same bug as in r260434.
SymbolFileDWARF::FindTypes has exponential worst-case when digging
through dependency DAG of .pcm files because each object file and .pcm
file may depend on an already-visited .pcm file, which may again have
dependencies. Fixed here by carrying a set of already visited
SymbolFiles around.
rdar://problem/56993424
Differential Revision: https://reviews.llvm.org/D70106
When we switched to the LLVM .debug_line parser, the .dSYM-style path
remapping logic stopped working for relative paths because of how
RemapSourceFile silently fails for relative paths. This patch both
makes the code more readable and fixes this particular bug.
One interesting thing I learned is that Module::RemapSourceFile() is a
macOS-only code path that operates on on the lldb::Module level and is
completely separate from target.source-map, which operates on a
per-Target level.
Differential Revision: https://reviews.llvm.org/D70037
rdar://problem/56924558
This patch removes the size_t return value and the append parameter
from the remainder of the Find.* functions in LLDB's internal API. As
in the previous patches, this is motivated by the fact that these
parameters aren't really used, and in the case of the append parameter
were frequently implemented incorrectly.
Differential Revision: https://reviews.llvm.org/D69119
llvm-svn: 375160
Summary:
Currently when invoking lldb-test symbols -dump-ast it parses all the debug symbols and calls print(...) on the TranslationUnitDecl.
While useful the TranslationUnitDecl::print(...) method gives us a higher level view then the dump from ASTDumper which is what we get when we invoke dump() on a specific AST node.
The main motivation for this change is allow us to verify that the AST nodes we create when we parse DWARF. For example in order to verify we are correctly using DIFlagExportSymbols added by D66667
Differential Revision: https://reviews.llvm.org/D67994
llvm-svn: 374570
Split out the logic to parse structure-like types into a separate
function, in an attempt to reduce the complexity of ParseTypeFromDWARF.
Inspired by discussion in https://reviews.llvm.org/D68130.
Differential Revision: https://reviews.llvm.org/D68422
llvm-svn: 373927
In r368345 I accidentally introduced a regression that would
over-report the number of matches found by FindTypes if the
DeclContext Filter was hit.
This patch simply removes the size_t return parameter altogether —
it's not that useful.
rdar://problem/55500457
Differential Revision: https://reviews.llvm.org/D68169
llvm-svn: 373344
I noticed that SymbolFileDWARFDebugMap::FindTypes was implementing it
incorrectly (passing append=false in a for-loop to recursive calls to
FindTypes would yield only the very last set of results), but instead
of fixing it, removing it seemed like an even better option.
rdar://problem/54412692
Differential Revision: https://reviews.llvm.org/D68171
llvm-svn: 373224
This implements
DWARFASTParserClang::EnsureAllDIEsInDeclContextHaveBeenParsed so as to
provide a faster way to ensure all DIEs linked to a certain declaration
context have been parsed.
Currently, we rely on SymbolFileDWARF::ParseDeclsForContext calling
DWARFASTParserClang::GetDIEForDeclContext, and only then
DWARFASTParserClang::GetDeclForUIDFromDWARF. This change shortcuts that
logic and removes redundant calls to DWARFASTParserClang::
GetClangDeclForDIE by deleting DIEs from the m_decl_ctx_to_die map once
they have been parsed.
Differential Revision: https://reviews.llvm.org/D67760
Patch by Guilherme Andrade <guiandrade@google.com>.
llvm-svn: 372744
Summary:
At the moment, when trying to import the `std` module in LLDB, we look at the imported modules used in the compiled program
and try to infer the Clang configuration we need from the DWARF module-import. That was the initial idea but turned out to
cause a few problems or inconveniences:
* It requires that users compile their programs with C++ modules. Given how experimental C++ modules are makes this feature inaccessible
for many users. Also it means that people can't just get the benefits of this feature for free when we activate it by default
(and we can't just close all the associated bug reports).
* Relying on DWARF's imported module tags (that are only emitted by default on macOS) means this can only be used when using DWARF (and with -glldb on Linux).
* We essentially hardcoded the C standard library paths on some platforms (Linux) or just couldn't support this feature on other platforms (macOS).
This patch drops the whole idea of looking at the imported module DWARF tags and instead just uses the support files of the compilation unit.
If we look at the support files and see file paths that indicate where the C standard library and libc++ are, we can just create the module
configuration this information. This fixes all the problems above which means we can enable all the tests now on Linux, macOS and with other debug information
than what we currently had. The only debug information specific code is now the iteration over external type module when -gmodules is used (as `std` and also the
`Darwin` module are their own external type module with their own files).
The meat of this patch is the CppModuleConfiguration which looks at the file paths from the compilation unit and then figures out the include paths
based on those paths. It's quite conservative in that it only enables modules if we find a single C library and single libc++ library. It's still missing some
test mode where we try to compile an expression before we actually activate the config for the user (which probably also needs some caching mechanism),
but for now it works and makes the feature usable.
Reviewers: aprantl, shafik, jdoerfert
Reviewed By: aprantl
Subscribers: mgorny, abidh, JDevlieghere, lldb-commits
Tags: #c_modules_in_lldb, #lldb
Differential Revision: https://reviews.llvm.org/D67760
llvm-svn: 372716
Add support for evaluating DW_OP_entry_value. This involves parsing
DW_TAG_call_site_parameter and wiring the information through to the expression
evaluator.
rdar://54496008
Differential Revision: https://reviews.llvm.org/D67376
llvm-svn: 371668
Summary:
The only reason for this function's existance is so that we could pass
the correct size into the DWARFExpression constructor. However, there is
no harm in passing the entire data extractor into the DWARFExpression,
since the same code is performing the size determination as well as the
subsequent parse. So, if we get malformed input or there's a bug in the
parser, we'd compute the wrong size anyway.
Additionally, reducing the number of entry points into the location list
parsing machinery makes it easier to switch the llvm debug_loc(lists)
parsers.
While inside, I added a couple of tests for invalid location list
handling.
Reviewers: JDevlieghere, clayborg
Subscribers: aprantl, javed.absar, kristof.beyls, lldb-commits
Differential Revision: https://reviews.llvm.org/D66789
llvm-svn: 370373
Summary:
The DWARFExpression methods have a lot of arguments. This removes two of
them by removing the ability to slice the expression via two offset+size
parameters. This is a functionality that it is not always needed, and
when it is, we already have a different handy way of slicing a data
extractor which we can use instead.
Reviewers: JDevlieghere, clayborg
Subscribers: aprantl, lldb-commits
Differential Revision: https://reviews.llvm.org/D66745
llvm-svn: 370027
This patch is also motivated by the Swift branch and is effectively NFC for the single-TypeSystem llvm.org branch.
In multi-language projects it is extremely common to have, e.g., a
Clang type and a similarly-named rendition of that same type in
another language. When searching for a type It is much cheaper to pass
a set of supported languages to the SymbolFile than having it
materialize every result and then rejecting the materialized types
that have the wrong language.
Differential Revision: https://reviews.llvm.org/D66546
<rdar://problem/54471165>
This reapplies r369690 with a previously missing constructor for LanguageSet.
llvm-svn: 369710
This patch is also motivated by the Swift branch and is effectively NFC for the single-TypeSystem llvm.org branch.
In multi-language projects it is extremely common to have, e.g., a
Clang type and a similarly-named rendition of that same type in
another language. When searching for a type It is much cheaper to pass
a set of supported languages to the SymbolFile than having it
materialize every result and then rejecting the materialized types
that have the wrong language.
Differential Revision: https://reviews.llvm.org/D66546
<rdar://problem/54471165>
llvm-svn: 369690
