methods for which the key function is guaranteed to be in another
translation unit. Unfortunately, this guarantee isn't the case when
dealing with shared libraries that fail to export these virtual method
definitions. 

I'm reopening PR6747 so we can consider this again at a later point in
time.

llvm-svn: 103741

"used" (e.g., we will refer to the vtable in the generated code) and
when they are defined (i.e., because we've seen the key function
definition). Previously, we were effectively tracking "potential
definitions" rather than uses, so we were a bit too eager about emitting
vtables for classes without key functions. 

The new scheme:
  - For every use of a vtable, Sema calls MarkVTableUsed() to indicate
  the use. For example, this occurs when calling a virtual member
  function of the class, defining a constructor of that class type,
  dynamic_cast'ing from that type to a derived class, casting
  to/through a virtual base class, etc.
  - For every definition of a vtable, Sema calls MarkVTableUsed() to
  indicate the definition. This happens at the end of the translation
  unit for classes whose key function has been defined (so we can
  delay computation of the key function; see PR6564), and will also
  occur with explicit template instantiation definitions.
 - For every vtable defined/used, we mark all of the virtual member
 functions of that vtable as defined/used, unless we know that the key
 function is in another translation unit. This instantiates virtual
 member functions when needed.
  - At the end of the translation unit, Sema tells CodeGen (via the
  ASTConsumer) which vtables must be defined (CodeGen will define
  them) and which may be used (for which CodeGen will define the
  vtables lazily). 

From a language perspective, both the old and the new schemes are
permissible: we're allowed to instantiate virtual member functions
whenever we want per the standard. However, all other C++ compilers
were more lazy than we were, and our eagerness was both a performance
issue (we instantiated too much) and a portability problem (we broke
Boost test cases, which now pass).

Notes:
  (1) There's a ton of churn in the tests, because the order in which
  vtables get emitted to IR has changed. I've tried to isolate some of
  the larger tests from these issues.
  (2) Some diagnostics related to
  implicitly-instantiated/implicitly-defined virtual member functions
  have moved to the point of first use/definition. It's better this
  way.
  (3) I could use a review of the places where we MarkVTableUsed, to
  see if I missed any place where the language effectively requires a
  vtable.

Fixes PR7114 and PR6564.

llvm-svn: 103718

available_externally linkage, since they may not have been given a
strong definition in another translation unit. Without this patch, the
following test case fails to link with a GCC-compiled libstdc++:

  #include <sstream>
  int main() { std::basic_stringbuf<char> bs; }

Fixes the last problem with the Boost.IO library.

llvm-svn: 103208

reference type, make sure that the initializer we build is the
of the appropriate type for the *reference*, not for the thing that it
refers to. Fixes PR7050.

llvm-svn: 103115

ivar class objects (NeXt runtime).
(radar 7900343).

llvm-svn: 102533

incomplete type.  Fixes PR6911.

llvm-svn: 102473

llvm-svn: 102219

NeXt's -fno-constant-cfstrings - wip.

llvm-svn: 102189

llvm-svn: 102112

llvm-svn: 101787

llvm-svn: 101786

If a method is virtual and the class key function is in another file, emit the method as available_externally.
Fixes PR6747

llvm-svn: 101757

llvm-svn: 101666

llvm-svn: 101153

llvm-svn: 101151

llvm-svn: 100926

llvm-svn: 100919

llvm-svn: 100918

mangling an unknown expression kind.  Also conveniently tells the user what
kind of expression they should add to the mangler!

llvm-svn: 100907

__cxxabiv1::__fundamental_type_info in every translation
unit. Previously, we would perform name lookup for
__cxxabiv1::__fundamental_type_info at the end of IRGen for a each
translation unit, to determine whether it was present. If so, we we
produce type information for all of the fundamental types. However,
this name lookup causes PCH deserialization of a significant part of the
translation unit, which has a woeful impact on performance.

With this change, we now look at each record type after we've
generated its vtable to see if it is
__cxxabiv1::__fundamental_type_info. If so, we generate type info for
all of the fundamental types. This works because
__cxxabiv1::__fundamental_type_info should always have a key function
(typically the virtual destructor), that will be defined once in the
support library. The fundamental type information will end up there.

Fixes <rdar://problem/7840011>.

llvm-svn: 100772

Reapply patch for adding support for address spaces and added a isVolatile field to memcpy, memmove, and memset.

llvm-svn: 100305

llvm-svn: 100200

Reapply patch for adding support for address spaces and added a isVolatile field to memcpy, memmove, and memset. 

llvm-svn: 100193

llvm-svn: 100093

addition to the inherent win, this eliminates the pointless
cost of going through the name -> mdkind stringmap that we
were paying.

llvm-svn: 99983

llvm-svn: 99949

llvm-svn: 99930

the typeinfo for the fundamental types.

Fixes PR6685.

llvm-svn: 99701

llvm-svn: 99317

declaration.

llvm-svn: 99311

Always emit associated thunks when emitting the function itself. Remove getVtableAddressPoint, it's not used.

llvm-svn: 99252

llvm-svn: 99251

llvm-svn: 99250

 - So much typing, so little gain...

Also, rename the __cxx_global_initialization function just to match llvm-gcc.

llvm-svn: 99039

shadowing it in the GlobalDeclMap.  Eliminates the string-uniquing
requirement for mangled names, which should help C++ codegen times a little.
Forces us to do string lookups instead of pointer lookups, which might hurt
codegen times a little across the board.  We'll see how it plays out.

Removing the string-uniquing requirement implicitly fixes any bugs like
PR6635 which arose from the fact that we had multiple uniquing tables for
different kinds of identifiers.

llvm-svn: 99012

iterations of this patch gave explicit template instantiation
link-once ODR linkage, which permitted the back end to eliminate
unused symbols. Weak ODR linkage still requires the symbols to be
generated.

llvm-svn: 98441

llvm-svn: 98425

llvm-svn: 98424

llvm-svn: 98332

them). Fixes PR6578.

llvm-svn: 98328