Fix the assembler to print a better relocatable expression error

diagnostic that includes location information.

Currently if one has this assembly:

	.quad (0x1234 + (4 * SOME_VALUE))

where SOME_VALUE is undefined ones gets the less than
useful error message with no location information:

% clang -c x.s
clang -cc1as: fatal error: error in backend: expected relocatable expression

With this fix one now gets a more useful error message
with location information:

% clang -c x.s 
x.s:5:8: error: expected relocatable expression
 .quad (0x1234 + (4 * SOME_VALUE))
       ^

To do this I plumbed the SMLoc through the MCObjectStreamer
EmitValue() and EmitValueImpl() interfaces so it could be used
when creating the MCFixup.

rdar://12391022


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206906 91177308-0d34-0410-b5e6-96231b3b80d8

lib/MC/MCParser/AsmParser.cpp

@@ -2364,7 +2364,7 @@ bool AsmParser::parseDirectiveValue(unsigned Size) {
           return Error(ExprLoc, "literal value out of range for directive");
         getStreamer().EmitIntValue(IntValue, Size);
       } else
-        getStreamer().EmitValue(Value, Size);
+        getStreamer().EmitValue(Value, Size, ExprLoc);
 
       if (getLexer().is(AsmToken::EndOfStatement))
         break;