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

llvm-svn: 206906

1 files changed, 2 insertions, 1 deletions

diff --git a/llvm/lib/MC/MCNullStreamer.cpp b/llvm/lib/MC/MCNullStreamer.cpp
index 2747090bd60..53f9548f68e 100644
--- a/llvm/lib/MC/MCNullStreamer.cpp
+++ b/llvm/lib/MC/MCNullStreamer.cpp
@@ -70,7 +70,8 @@ namespace {
                         uint64_t Size, unsigned ByteAlignment) override {}
     void EmitBytes(StringRef Data) override {}
 
-    void EmitValueImpl(const MCExpr *Value, unsigned Size) override {}
+    void EmitValueImpl(const MCExpr *Value, unsigned Size,
+                       const SMLoc &Loc = SMLoc()) override {}
     void EmitULEB128Value(const MCExpr *Value) override {}
     void EmitSLEB128Value(const MCExpr *Value) override {}
     void EmitGPRel32Value(const MCExpr *Value) override {}