MC: Don't crash after issuing a diagnostic.

Crashing is bad, m'kay? Fixing a 4 year old bug of my own creation.
Adding the testcase now which I should have added then which would have
long since caught this.

The problem is that printMessage() will display the diagnostic but not
set HadError to true, resulting in the assembler continuing on its way
and trying to create relocations for things that may not allow them or
otherwise get itself into trouble. Using the Error() helper function
here rather than calling printMessage() directly resolves this.

rdar://23133240

llvm-svn: 250557

2 files changed, 10 insertions, 3 deletions

diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index 9c542244fc7..c003c797dd9 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -690,9 +690,8 @@ bool AsmParser::Run(bool NoInitialTextSection, bool NoFinalize) {
         // FIXME: We would really like to refer back to where the symbol was
         // first referenced for a source location. We need to add something
         // to track that. Currently, we just point to the end of the file.
-        printMessage(getLexer().getLoc(), SourceMgr::DK_Error,
-                     "assembler local symbol '" + Sym->getName() +
-                         "' not defined");
+        return Error(getLexer().getLoc(), "assembler local symbol '" +
+                                              Sym->getName() + "' not defined");
     }
   }
 
diff --git a/llvm/test/MC/AsmParser/undefined-local-symbol.s b/llvm/test/MC/AsmParser/undefined-local-symbol.s
new file mode 100644
index 00000000000..280fc555980
--- /dev/null
+++ b/llvm/test/MC/AsmParser/undefined-local-symbol.s
@@ -0,0 +1,8 @@
+# RUN: not llvm-mc -triple i386-apple-darwin -filetype=obj -o /dev/null %s 2>&1 | FileCheck %s
+
+# NOTE: apple-darwin portion of the triple is to enforce the convention choice
+#       of what an assembler local symbol looks like (i.e., 'L' prefix.)
+
+# CHECK: error: assembler local symbol 'Lbar' not defined
+foo:
+  jmp Lbar