- This has pros and cons, but for now the pros seem to significantly
   outway the con.

The con is that we will always need to cast in the runtime
implementation to a struct type, if we wish to access an interface
directly.

The pros are:
 - Avoid the cost of generating types which are used. Most
   manipulation of Objective-C objects is done through messages, and
   only the implementation of a class will directly access
   memory. Previously, we would convert the type even if it only
   appear as a function parameter, for example.

 - We don't need to worry about incomplete types, and
   UpdateCompletedType for interfaces is gone.

 - It becomes easier to narrow the interface to the shadow struct for
   Objective-C interfaces (so it can be eliminated).

Currently the runtimes still use the CodeGenTypes machinery to
generate the LLVM structure they need via ConvertTagDecl, but this can
eventually be replaced.

llvm-svn: 69797

underlying llvm::StructType for an interface.

llvm-svn: 69796

 - If we don't find a file looking relative to the current working
   directory, fall back to header search. This is closer to what would
   happen if the lookup was starting from right directory in the first
   place (except it will find files in the directory of the main
   source file, which I *think* should not be found).

 - PR3992.

llvm-svn: 69794

llvm-svn: 69793

Real fix for PR3549, by using caching for predecessor counts in addition to the predecessors themselves.  This halves the time
to optimize the testcase, beyond what my previous patch did.

llvm-svn: 69792

llvm-svn: 69791

llvm-svn: 69790

llvm-svn: 69789

Use PredIteratorCache in LCSSA, which gives a 37% overall speedup on the testcase from PR3549.  More improvements to come.

llvm-svn: 69788

 - For now, this means we are always doing the address computations by
   hand instead of constructing a proper GEP. Right now, however, this
   is less important than having fewer entry points to dealing with
   Objective-C interface layout.

llvm-svn: 69787

llvm-svn: 69786

Patch by Peter Johnson.

llvm-svn: 69785

llvm-svn: 69784

llvm-svn: 69783

llvm-svn: 69782

llvm-svn: 69781

way to serialize selectors yet.

llvm-svn: 69780

fix a couple of bugs in reader support for ObjCInterfaceDecl,
and add support for reading ObjCInterfaceType.

llvm-svn: 69779

llvm-svn: 69778

start of the declspec.  The fixit still goes there, and we underline
the declspec.  This helps when the start of the declspec came from a
macro that expanded from a system header.  For example, we now produce:

t.c:2:8: warning: type specifier missing, defaults to 'int' [-Wimplicit-int]
static x;
~~~~~~ ^

llvm-svn: 69777

llvm-svn: 69776

llvm-svn: 69775

Reorganize built-in initialization to separate the creation of target builtins from marking IdentifierInfos as builtins. No functionality change

llvm-svn: 69774

llvm-svn: 69773

llvm-svn: 69772

 - Superclasses are now always laid out their shadow structure at the
   first field.

 - Prior to this, the entire class heirarchy was flattened into a
   single structure which meant that alignment, padding, and bitfields
   weren't packed correctly (the ASTRecordLayout was correct however,
   which meant our debug info didn't coincide with ivar offsets, for
   example).

 - This is still very suboptimal, but I believe the ivar layout itself
   is now at least close to correct.

 - <rdar://problem/6773388> error: objc[29823]: layout bitmap sliding
   backwards

llvm-svn: 69771

by marking the predefines buffer as a system header.  The problem 
with stdint is that it was getting problems like this:

/Volumes/Projects/cvs/llvm/Debug/lib/clang/1.0/include/stdint.h:43:9: warning: 'long long' is an extension when C99 mode is not enabled
typedef __INT64_TYPE__ int64_t;
        ^
<built-in>:73:29: note: instantiated from:
#define __INT64_TYPE__ long long
                            ^

We correctly silence warnings in system headers, but only if the 
spelling location of the token came from the system header.  This is
designed so that if you use a system macro in your code that you don't
get punished for its definition.  This is all cool except that the 
predefines buffer wasn't considered a system header.

llvm-svn: 69770

llvm-svn: 69767

7 left for 64-bit ABI.

llvm-svn: 69766

llvm-svn: 69765

llvm-svn: 69764

produces just 14 dead "declares" in llvm ir instead of 19.

llvm-svn: 69763

rdar://6809612

llvm-svn: 69762

llvm-svn: 69761

for scoping to match C99 even when in C89 mode.  This patch fixes this 
(eliminating a "redefinition of thisKey" error), and also prevents non-sensical
diagnostics in -pedantic mode like this:

t.m:7:8: warning: variable declaration in for loop is a C99-specific feature
  for (id thisKey in keys) ;
       ^

llvm-svn: 69760

llvm-svn: 69758

llvm-svn: 69757

extern.  Previously we would warn about it and ignore the attribute.
This is incorrect, it should be handled as a c89 "extern inline" 
function.  Many thanks to Matthieu Castet for pointing this out and
beating me over the head until I got it.

PR3988: extern inline function are not externally visible
llvm-svn: 69756

This optimization improves performance on the Carbon-prefixed "Hello,
World!" example by 57%. For reference, we're now about 2.25x faster
than GCC PCH. We're also pulling in far less of the PCH file:

*** PCH Statistics:
  411/20693 types read (1.986179%)
  2553/59230 declarations read (4.310316%)
  1093/44646 identifiers read (2.448148%)
  1/32954 statements read (0.003035%)
  21/6187 macros read (0.339421%)

llvm-svn: 69755

llvm-svn: 69754