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
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index b6da85e..7fb57ea 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -179,10 +179,11 @@
       // Store the alignment in the bitcode as a 16-bit raw value instead of a
       // 5-bit log2 encoded value. Shift the bits above the alignment up by
       // 11 bits.
-      uint64_t FauxAttr = PAWI.Attrs & 0xffff;
+      uint64_t FauxAttr = PAWI.Attrs.Raw() & 0xffff;
       if (PAWI.Attrs & Attribute::Alignment)
-        FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
-      FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
+        FauxAttr |= (1ull<<16)<<
+            (((PAWI.Attrs & Attribute::Alignment).Raw()-1) >> 16);
+      FauxAttr |= (PAWI.Attrs.Raw() & (0x3FFull << 21)) << 11;
 
       Record.push_back(FauxAttr);
     }