Classes can be defined in multiple translation units. This means that
the static constexpr data members should have identical initializers in
all translation units. Implement this by giving the reference temporary
linkonce_odr linkage.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@229900 91177308-0d34-0410-b5e6-96231b3b80d8
The current implementation causes link-time ODR violations when the delete symbols are exported into the dynamic table.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@229241 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This is especially important for targets that use multiple address spaces,
and commonly place global variables in address spaces other than zero.
Fixes PR22383
Test Plan: New test case added: llvm-used.cu
Reviewers: jingyue
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D7345
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@227861 91177308-0d34-0410-b5e6-96231b3b80d8
Currently we emit DeferredDeclsToEmit in reverse order. This patch changes that.
The advantages of the change are that
* The output order is a bit closer to the source order. The change to
test/CodeGenCXX/pod-member-memcpys.cpp is a good example.
* If we decide to deffer more, it will not cause as large changes in the
estcases as it would without this patch.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@226751 91177308-0d34-0410-b5e6-96231b3b80d8
This produces comdats for vtables, typeinfo, typeinfo names, and vtts.
When combined with llvm not producing implicit comdats, not doing this would
cause code bloat on ELF and link errors on COFF.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@226227 91177308-0d34-0410-b5e6-96231b3b80d8
When combined with llvm not producing implicit comdats, not doing this would
cause code bloat on ELF and link errors on COFF.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@226211 91177308-0d34-0410-b5e6-96231b3b80d8
Sorry for the noise, I managed to miss a bunch of recent regressions of
include orderings here. This should actually sort all the includes for
Clang. Again, no functionality changed, this is just a mechanical
cleanup that I try to run periodically to keep the #include lines as
regular as possible across the project.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@225979 91177308-0d34-0410-b5e6-96231b3b80d8
The llvm IR until recently had no support for comdats. This was a problem when
targeting C++ on ELF/COFF as just using weak linkage would cause quite a bit of
dead bits to remain on the executable (unless -ffunction-sections,
-fdata-sections and --gc-sections were used).
To fix the problem, llvm's codegen will just assume that any weak or linkonce
that is not in an explicit comdat should be output in one with the same name as
the global.
This unfortunately breaks cases like pr19848 where a weak symbol is not
xpected to be part of any comdat.
Now that we have explicit comdats in the IR, we can finally get both cases
right.
This first patch just makes clang give explicit comdats to GlobalValues where
t is allowed to.
A followup patch to llvm will then stop implicitly producing comdats.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@225705 91177308-0d34-0410-b5e6-96231b3b80d8
Their linkage can change if they are later explicitly instantiated. We would
previously emit such functions eagerly (as opposed to lazily on first use) if
they have a 'dllexport' or 'used' attribute, and fail an assert when hitting the
explicit instantiation.
This is achieved by replacing the old CodeGenModule::MayDeferGeneration() method
with two new ones: MustBeEmitted() and MayBeEmittedEagerly().
Differential Revision: http://reviews.llvm.org/D6674
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@225570 91177308-0d34-0410-b5e6-96231b3b80d8
having OptimizeNone remove them again, just don't add them in the
first place if the function already has OptimizeNone.
Note that MinSize can still appear due to attributes on different
declarations; a future patch will address that.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@224047 91177308-0d34-0410-b5e6-96231b3b80d8
The logic for lowering profiling counters has been moved to an LLVM
pass. Emit the intrinsics rather than duplicating the whole pass in
clang.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@223683 91177308-0d34-0410-b5e6-96231b3b80d8
ARM ABI specifies that all the libcalls use soft FP ABI
(even hard FP binaries). These days clang emits _mulsc3 / _muldc3
calls with default (C) calling convention which would be translated
into AAPCS_VFP LLVM calling and thus the result of complex
multiplication will be bogus.
Introduce a way for a target to specify explicitly calling
convention for libcalls. Right now this is temporary correctness
fix. Ultimately, we'll end with intrinsic for complex
multiplication and all calling convention decisions for libcalls
will be put into backend.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@223123 91177308-0d34-0410-b5e6-96231b3b80d8
Richard rejected my Sema change to interpret an integer literal zero in
a varargs context as a null pointer, so -Wsentinel sees an integer
literal zero and fires off a warning. Only CodeGen currently knows that
it promotes integer literal zeroes in this context to pointer size on
Windows. I didn't want to teach -Wsentinel about that compatibility
hack. Therefore, I'm migrating to C++11 nullptr.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@223079 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This distinguishes between -fpic and -fPIC now, with the additions in LLVM for
PIC level support.
Test Plan: No regressions
Reviewers: echristo, rafael
Reviewed By: rafael
Subscribers: rnk, emaste, llvm-commits
Differential Revision: http://reviews.llvm.org/D5400
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@222227 91177308-0d34-0410-b5e6-96231b3b80d8
For all threadprivate variables which have constructor/destructor emit call to void __kmpc_threadprivate_register(ident_t * <Current Location>, void *<Original Global Addr>, kmpc_ctor <Constructor>, kmpc_cctor NULL, kmpc_dtor <Destructor>);
In expressions all references to such variables are replaced by calls to void *__kmpc_threadprivate_cached(ident_t *<Current Location>, kmp_int32 <Current Thread Id>, void *<Original Global Addr>, size_t <Size of Data>, void ***<Pointer to autogenerated cache – array of private copies of threadprivate variable>);
Test test/OpenMP/threadprivate_codegen.cpp checks that codegen is correct. Also it checks that codegen is correct after serialization/deserialization and one of passes verifies debug info.
Differential Revision: http://reviews.llvm.org/D4002
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@221663 91177308-0d34-0410-b5e6-96231b3b80d8
Use the bitmask to store the set of enabled sanitizers instead of a
bitfield. On the negative side, it makes syntax for querying the
set of enabled sanitizers a bit more clunky. On the positive side, we
will be able to use SanitizerKind to eventually implement the
new semantics for -fsanitize-recover= flag, that would allow us
to make some sanitizers recoverable, and some non-recoverable.
No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@221558 91177308-0d34-0410-b5e6-96231b3b80d8
It turns out that MinGW never dllimports of exports inline functions.
This means that code compiled with Clang would fail to link with
MinGW-compiled libraries since we might try to import functions that
are not imported.
To fix this, make Clang never dllimport inline functions when targeting
MinGW.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@221154 91177308-0d34-0410-b5e6-96231b3b80d8
This commit changes the way we blacklist global variables in ASan.
Now the global is excluded from instrumentation (either regular
bounds checking, or initialization-order checking) if:
1) Global is explicitly blacklisted by its mangled name.
This part is left unchanged.
2) SourceLocation of a global is in blacklisted source file.
This changes the old behavior, where instead of looking at the
SourceLocation of a variable we simply considered llvm::Module
identifier. This was wrong, as identifier may not correspond to
the file name, and we incorrectly disabled instrumentation
for globals coming from #include'd files.
3) Global is blacklisted by type.
Now we build the type of a global variable using Clang machinery
(QualType::getAsString()), instead of llvm::StructType::getName().
After this commit, the active users of ASan blacklist files
may have to revisit them (this is a backwards-incompatible change).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@220097 91177308-0d34-0410-b5e6-96231b3b80d8
This commit changes the way we blacklist functions in ASan, TSan,
MSan and UBSan. We used to treat function as "blacklisted"
and turned off instrumentation in it in two cases:
1) Function is explicitly blacklisted by its mangled name.
This part is not changed.
2) Function is located in llvm::Module, whose identifier is
contained in the list of blacklisted sources. This is completely
wrong, as llvm::Module may not correspond to the actual source
file function is defined in. Also, function can be defined in
a header, in which case user had to blacklist the .cpp file
this header was #include'd into, not the header itself.
Such functions could cause other problems - for instance, if the
header was included in multiple source files, compiled
separately and linked into a single executable, we could end up
with both instrumented and non-instrumented version of the same
function participating in the same link.
After this change we will make blacklisting decision based on
the SourceLocation of a function definition. If a function is
not explicitly defined in the source file, (for example, the
function is compiler-generated and responsible for
initialization/destruction of a global variable), then it will
be blacklisted if the corresponding global variable is defined
in blacklisted source file, and will be instrumented otherwise.
After this commit, the active users of blacklist files may have
to revisit them. This is a backwards-incompatible change, but
I don't think it's possible or makes sense to support the
old incorrect behavior.
I plan to make similar change for blacklisting GlobalVariables
(which is ASan-specific).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@219997 91177308-0d34-0410-b5e6-96231b3b80d8
They cannot be written to, so marking them const makes sense and may improve
optimisation.
As a side-effect, SectionInfos has to be moved from Sema to ASTContext.
It also fixes this problem, that occurs when compiling ATL:
warning LNK4254: section 'ATL' (C0000040) merged into '.rdata' (40000040) with different attributes
The ATL headers are putting variables in a special section that's marked
read-only. However, Clang currently can't model that read-onlyness in the IR.
But, by making the variables const, the section does become read-only, and
the linker warning is avoided.
Differential Revision: http://reviews.llvm.org/D5812
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@219960 91177308-0d34-0410-b5e6-96231b3b80d8
CodeGen wouldn't mark the aliasee as thread_local if the aliasee was a
tentative definition.
Even if the definition was already emitted, it would never mark the
alias as thread_local.
This fixes PR21288.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@219859 91177308-0d34-0410-b5e6-96231b3b80d8
This patch makes sure that the dllexport attribute is transferred to the alias when such alias is created. It only affects the Itanium ABI because for the MSVC ABI a workaround is in place to not generate aliases of dllexport ctors/dtors.
A new CodeGenModule function is provided, CodeGenModule::setAliasAttributes, to factor the code for transferring attributes to aliases.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@218159 91177308-0d34-0410-b5e6-96231b3b80d8
There are situations when clang knows that the C1 and C2 constructors
or the D1 and D2 destructors are identical. We already optimize some
of these cases, but cannot optimize it when the GlobalValue is
weak_odr.
The problem with weak_odr is that an old TU seeing the same code will
have a C1 and a C2 comdat with the corresponding symbols. We cannot
suddenly start putting the C2 symbol in the C1 comdat as we cannot
guarantee that the linker will not pick a .o with only C1 in it.
The solution implemented by GCC is to expand the ABI to have a comdat
whose name uses a C5/D5 suffix and always has both symbols. That is
what this patch implements.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@217874 91177308-0d34-0410-b5e6-96231b3b80d8
For the following code:
__declspec(dllimport) int f(int x);
int user(int x) {
return f(x);
}
int f(int x) { return 1; }
Clang will drop the dllimport attribute in the AST, but CodeGen would have
already put it on the LLVM::Function, and that would never get updated.
(The same thing happens for global variables.)
This makes Clang check dropped DLL attribute case each time the LLVM object
is referenced.
This isn't perfect, because we will still get it wrong if the function is
never referenced by codegen after the attribute is dropped, but this handles
the common cases and makes us not fail in the verifier.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@216699 91177308-0d34-0410-b5e6-96231b3b80d8
int __declspec(align(16)) foo; is a tentative definition but the storage
for that variable should not have CommonLinkage.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214828 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds the '-fcoverage-mapping' option which
allows clang to generate the coverage mapping information
that can be used to provide code coverage analysis using
the execution counts obtained from the instrumentation
based profiling (-fprofile-instr-generate).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214752 91177308-0d34-0410-b5e6-96231b3b80d8
It is responsible for generating metadata consumed by sanitizer instrumentation
passes in the backend. Move several methods from CodeGenModule to SanitizerMetadata.
For now the class is stateless, but soon it won't be the case.
Instead of creating globals providing source-level information to ASan, we will create
metadata nodes/strings which will be turned into actual global variables in the
backend (if needed).
No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214564 91177308-0d34-0410-b5e6-96231b3b80d8
Original message:
Fix iterator invalidation issues that are breaking my modules buildbot's
bootstrap.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214555 91177308-0d34-0410-b5e6-96231b3b80d8
they're somehow missing a body. Looks like this was left behind when the loop
was generalized, and it's not been problematic before because without modules,
a used, implicit special member function declaration must be a definition.
This was resulting in us trying to emit a constructor declaration rather than
a definition, and producing a constructor missing its member initializers.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214473 91177308-0d34-0410-b5e6-96231b3b80d8
lengths! In passing, simplify string literal deduplication by relying on LLVM
to deduplicate the underlying constant values.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214222 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This change adds description of globals created by UBSan
instrumentation (UBSan handlers, type descriptors, filenames) to
llvm.asan.globals metadata, effectively "blacklisting" them. This can
dramatically decrease the data section in binaries built with UBSan+ASan,
as UBSan tends to create a lot of handlers, and ASan instrumentation
increases the global size to at least 64 bytes.
Test Plan: clang regression test suite
Reviewers: rsmith
Reviewed By: rsmith
Subscribers: cfe-commits, byoungyoung, kcc
Differential Revision: http://reviews.llvm.org/D4575
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@213392 91177308-0d34-0410-b5e6-96231b3b80d8
This makes us emit dllexported in-class initialized static data members (which
are treated as definitions in MSVC), even when they're not referenced.
It also makes their special linkage reflected in the GVA linkage instead of
getting massaged in CodeGen.
Differential Revision: http://reviews.llvm.org/D4563
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@213304 91177308-0d34-0410-b5e6-96231b3b80d8
Currently ASan instrumentation pass creates a string with global name
for each instrumented global (to include global names in the error report). Global
name is already mangled at this point, and we may not be able to demangle it
at runtime (e.g. there is no __cxa_demangle on Android).
Instead, create a string with fully qualified global name in Clang, and pass it
to ASan instrumentation pass in llvm.asan.globals metadata. If there is no metadata
for some global, ASan will use the original algorithm.
This fixes https://code.google.com/p/address-sanitizer/issues/detail?id=264.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@212872 91177308-0d34-0410-b5e6-96231b3b80d8
Turn llvm::SpecialCaseList into a simple class that parses text files in
a specified format and knows nothing about LLVM IR. Move this class into
LLVMSupport library. Implement two users of this class:
* DFSanABIList in DFSan instrumentation pass.
* SanitizerBlacklist in Clang CodeGen library.
The latter will be modified to use actual source-level information from frontend
(source file names) instead of unstable LLVM IR things (LLVM Module identifier).
Remove dependency edge from ClangCodeGen/ClangDriver to LLVMTransformUtils.
No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@212643 91177308-0d34-0410-b5e6-96231b3b80d8
Get rid of cached CodeGenModule::SanOpts, which was used to turn off
sanitizer codegen options if current LLVM Module is blacklisted, and use
plain LangOpts.Sanitize instead.
1) Some codegen decisions (turning TBAA or writable strings on/off)
shouldn't depend on the contents of blacklist.
2) llvm.asan.globals should *always* be created, even if the module
is blacklisted - soon Clang's CodeGen where we read sanitizer
blacklist files, so we should properly report which globals are
blacklisted to the backend.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@212499 91177308-0d34-0410-b5e6-96231b3b80d8
Let's not expose ABI specific minutia inside of CodeGenModule and Type.
Instead, let's abstract it through CXXABI.
This gets rid of:
CodeGenModule::getCompleteObjectLocator,
CodeGenModule::EmitFundamentalTypeDescriptor{s,},
CodeGenModule::getMSTypeDescriptor,
CodeGenModule::getMSCompleteObjectLocator,
CGCXXABI::shouldRTTIBeUnique,
CGCXXABI::classifyRTTIUniqueness.
CGRTTI was *almost* entirely centered around providing Itanium-style
RTTI information. Instead of providing interfaces that only it
consumes, move it to the ItaniumCXXABI implementation file. This allows
it to have access to Itanium-specific implementation details without
providing useless expansion points for the Microsoft ABI side.
Differential Revision: http://reviews.llvm.org/D4261
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@212435 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Because a global created by GetOrCreateLLVMGlobal() is not finalised until later viz:
extern char a[];
char f(){ return a[5];}
char a[10];
Change MangledDeclNames to use a MapVector rather than a DenseMap so that the
Metadata is output in order of original declaration, so to make deterministic
and improve human readablity.
Differential Revision: http://reviews.llvm.org/D4176
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@212263 91177308-0d34-0410-b5e6-96231b3b80d8
See https://code.google.com/p/address-sanitizer/issues/detail?id=299 for the
original feature request.
Introduce llvm.asan.globals metadata, which Clang (or any other frontend)
may use to report extra information about global variables to ASan
instrumentation pass in the backend. This metadata replaces
llvm.asan.dynamically_initialized_globals that was used to detect init-order
bugs. llvm.asan.globals contains the following data for each global:
1) source location (file/line/column info);
2) whether it is dynamically initialized;
3) whether it is blacklisted (shouldn't be instrumented).
Source location data is then emitted in the binary and can be picked up
by ASan runtime in case it needs to print error report involving some global.
For example:
0x... is located 4 bytes to the right of global variable 'C::array' defined in '/path/to/file:17:8' (0x...) of size 40
These source locations are printed even if the binary doesn't have any
debug info.
This is an ABI-breaking change. ASan initialization is renamed to
__asan_init_v4(). Pre-built libraries compiled with older Clang will not work
with the fresh runtime.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@212188 91177308-0d34-0410-b5e6-96231b3b80d8
Improve the warning when building with -fprofile-instr-use and a file
appears not to have been profiled at all. This keys on whether a
function is defined in the main file or not to avoid false negatives
when one includes a header with functions that have been profiled.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211760 91177308-0d34-0410-b5e6-96231b3b80d8
Add module flags metadata to record the settings for enum and wchar width,
to allow correct ARM build attribute generation
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211354 91177308-0d34-0410-b5e6-96231b3b80d8
The backing store of thread local variables is internal for OS X and all
accesses must go through the thread wrapper.
However, individual TUs may have inlined through the thread wrapper.
To fix this, give the thread wrapper functions WeakAnyLinkage. This
prevents them from getting inlined into call-sites.
This fixes PR19989.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@210632 91177308-0d34-0410-b5e6-96231b3b80d8
Add driver and frontend support for the GCC -Wframe-larger-than=bytes warning.
This is the first GCC-compatible backend diagnostic built around LLVM's
reporting feature.
This commit adds infrastructure to perform reverse lookup from mangled names
emitted after LLVM IR generation. We use that to resolve precise locations and
originating AST functions, lambdas or block declarations to produce seamless
codegen-guided diagnostics.
An associated change, StringMap now maintains unique mangled name strings
instead of allocating copies. This is a net memory saving in C++ and a small
hit for C where we no longer reuse IdentifierInfo storage, pending further
optimisation.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@210293 91177308-0d34-0410-b5e6-96231b3b80d8
Share mode code between these functions and re-structure them in a way
which shows how similar they actually are. The latter function works well
with literals of multi-byte chars and does a GlobalVariable name mangling
(if global strings are non-writable).
No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@210212 91177308-0d34-0410-b5e6-96231b3b80d8
The only remaining user didn't actually use the non-dynamic storage facility
this class provides.
The std::string is transitional and likely to be StringRefized shortly.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@210058 91177308-0d34-0410-b5e6-96231b3b80d8
Clang knows about the sanitizer blacklist and it makes no sense to
add global to the list of llvm.asan.dynamically_initialized_globals if it
will be blacklisted in the instrumentation pass anyway. Instead, we should
do as much blacklisting as possible (if not all) in the frontend.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@209789 91177308-0d34-0410-b5e6-96231b3b80d8
MSVC doesn't export these functions, so trying to import them doesnt' work.
Also, don't let any dll attributes on the CXXDestructorDecl influence the
thunk's linkage -- they should always be linkonce_odr.
This takes care of the FIXME's for this in Nico's tests.
Differential Revision: http://reviews.llvm.org/D3930
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@209706 91177308-0d34-0410-b5e6-96231b3b80d8
Initializers of global data that can appear multiple TUs (static data
members of class templates or __declspec(selectany) data) are now in a
comdat group keyed on the global variable being initialized. On
non-Windows platforms, this is a code size and startup time
optimization. On Windows, this is necessary for ABI compatibility with
MSVC.
Fixes PR16959.
Reviewers: rsmith
Differential Revision: http://reviews.llvm.org/D3811
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@209555 91177308-0d34-0410-b5e6-96231b3b80d8
This was fairly broken. For example,
@__dso_handle would or would not get an unnamed_addr depending on how many
global destructors were used in a translation unit.
The consensus was that not every runtime variable is unnamed_addr and that
__dso_handle handle should not be, so just don't add unnamed_addr in
CreateRuntimeVariable.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@209484 91177308-0d34-0410-b5e6-96231b3b80d8
behavior on mismatch. The AutoUpgrader will drop incompatible debug info
any way and also emit a warning diagnostic for it.
rdar://problem/16926122
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@209182 91177308-0d34-0410-b5e6-96231b3b80d8
Now that llvm cannot represent alias cycles, we have to diagnose erros just
before trying to close the cycle. This degrades the errors a bit. The real
solution is what it was before: if we want to provide good errors for these
cases, we have to be able to find a clang level decl given a mangled name
and produce the error from Sema.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@209008 91177308-0d34-0410-b5e6-96231b3b80d8
Alexey Bataev