Add a GlobalAlias::isValidLinkage to reduce code duplication.

Thanks to Reid Kleckner for the suggestion.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192298 91177308-0d34-0410-b5e6-96231b3b80d8
Fix a bug in Dead Argument Elimination.

  If a function seen at compile time is not necessarily the one linked to
the binary being built, it is illegal to change the actual arguments
passing to it. 

  e.g. 
   --------------------------
   void foo(int lol) {
     // foo() has linkage satisifying isWeakForLinker()
     // "lol" is not used at all.
   }

   void bar(int lo2) {
      // xform to foo(undef) is illegal, as compiler dose not know which
      // instance of foo() will be linked to the the binary being built.
      foo(lol2); 
   }
  -----------------------------

  Such functions can be captured by isWeakForLinker(). NOTE that
mayBeOverridden() is insufficient for this purpose as it dosen't include
linkage types like AvailableExternallyLinkage and LinkOnceODRLinkage.
Take link_odr* as an example, it indicates a set of *EQUIVALENT* globals
that can be merged at link-time. However, the semantic of 
*EQUIVALENT*-functions includes parameters. Changing parameters breaks
the assumption.

  Thank John McCall for help, especially for the explanation of subtle
difference between linkage types.

  rdar://11546243


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192302 91177308-0d34-0410-b5e6-96231b3b80d8
Flip the ownership of MCStreamer and MCTargetStreamer.

MCStreamer now owns the target streamer. This prevents leaking the target
streamer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192303 91177308-0d34-0410-b5e6-96231b3b80d8
Add missing releases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192304 91177308-0d34-0410-b5e6-96231b3b80d8
Debug Info: In DIBuilder, the context field of a forward decl is updated
to use DIScopeRef.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192309 91177308-0d34-0410-b5e6-96231b3b80d8
llvm-c: Make target initializer functions external functions in lib.

Making them proper functions defined in the (shared)lib instead of
static inlines defined in the header files makes it possible to
actually distribute a binary compiled against the shared library
without having to worry about getting undefined symbol errors when
calling e.g LLVMInitializeAllTargetInfos because the shared library on
the other system was compiled with different targets.

Differential Revision: http://llvm-reviews.chandlerc.com/D1714



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192316 91177308-0d34-0410-b5e6-96231b3b80d8
Debug Info: In DIBuilder, the context and type fields of template_type and
template_value are updated to use DIRef.

A paired commit at clang is required due to changes to DIBuilder.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192320 91177308-0d34-0410-b5e6-96231b3b80d8
Revert "llvm-c: Make target initializer functions external functions in lib."

This reverts commit r192316. The original change introduced circular
dependencies between libTarget and backends. That would broke a build unless
link everything into one big binary.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192329 91177308-0d34-0410-b5e6-96231b3b80d8
[mips] Do not generate INS/EXT nodes if target does not have support for
ins/ext.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192330 91177308-0d34-0410-b5e6-96231b3b80d8