Extend Attributes to 64 bits

Problem: LLVM needs more function attributes than currently available (32 bits).
One such proposed attribute is "address_safety", which shows that a function is being checked for address safety (by AddressSanitizer, SAFECode, etc).

Solution:
- extend the Attributes from 32 bits to 64-bits
- wrap the object into a class so that unsigned is never erroneously used instead
- change "unsigned" to "Attributes" throughout the code, including one place in clang.
- the class has no "operator uint64 ()", but it has "uint64_t Raw() " to support packing/unpacking.
- the class has "safe operator bool()" to support the common idiom:  if (Attributes attr = getAttrs()) useAttrs(attr);
- The CTOR from uint64_t is marked explicit, so I had to add a few explicit CTOR calls
- Add the new attribute "address_safety". Doing it in the same commit to check that attributes beyond first 32 bits actually work.
- Some of the functions from the Attribute namespace are worth moving inside the class, but I'd prefer to have it as a separate commit.

Tested:
"make check" on Linux (32-bit and 64-bit) and Mac (10.6)
built/run spec CPU 2006 on Linux with clang -O2.


This change will break clang build in lib/CodeGen/CGCall.cpp.
The following patch will fix it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148553 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/Analysis.cpp

@@ -259,7 +259,7 @@ bool llvm::isInTailCallPosition(ImmutableCallSite CS, Attributes CalleeRetAttr,
   // Conservatively require the attributes of the call to match those of
   // the return. Ignore noalias because it doesn't affect the call sequence.
   const Function *F = ExitBB->getParent();
-  unsigned CallerRetAttr = F->getAttributes().getRetAttributes();
+  Attributes CallerRetAttr = F->getAttributes().getRetAttributes();
   if ((CalleeRetAttr ^ CallerRetAttr) & ~Attribute::NoAlias)
     return false;
 
@@ -299,7 +299,7 @@ bool llvm::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node,
 
   // Conservatively require the attributes of the call to match those of
   // the return. Ignore noalias because it doesn't affect the call sequence.
-  unsigned CallerRetAttr = F->getAttributes().getRetAttributes();
+  Attributes CallerRetAttr = F->getAttributes().getRetAttributes();
   if (CallerRetAttr & ~Attribute::NoAlias)
     return false;