llvm-dis: Stop crashing when dropping debug info

Since r199356, we've printed a warning when dropping debug info.
r225562 started crashing on that, since it registered a diagnostic
handler that only expected errors.  This fixes the handler to expect
other severities.  As a side effect, it now prints "error: " at the
start of error messages, similar to `llvm-as`.

There was a testcase for r199356, but it only really checked the
assembler.  Move `test/Bitcode/drop-debug-info.ll` to `test/Assembler`,
and introduce `test/Bitcode/drop-debug-info.3.5.ll` (and companion
`.bc`) to test the bitcode reader.

Note: tools/gold/gold-plugin.cpp has an equivalent bug, but I'm not sure
what the best fix is there.  I'll file a PR.

llvm-svn: 230416

1 files changed, 10 insertions, 3 deletions

diff --git a/llvm/tools/llvm-dis/llvm-dis.cpp b/llvm/tools/llvm-dis/llvm-dis.cpp
index 1349ecc85a4..1c3a9ced0ff 100644
--- a/llvm/tools/llvm-dis/llvm-dis.cpp
+++ b/llvm/tools/llvm-dis/llvm-dis.cpp
@@ -115,14 +115,21 @@ public:
 } // end anon namespace
 
 static void diagnosticHandler(const DiagnosticInfo &DI, void *Context) {
-  assert(DI.getSeverity() == DS_Error && "Only expecting errors");
-
   raw_ostream &OS = errs();
   OS << (char *)Context << ": ";
+  switch (DI.getSeverity()) {
+  case DS_Error: OS << "error: "; break;
+  case DS_Warning: OS << "warning: "; break;
+  case DS_Remark: OS << "remark: "; break;
+  case DS_Note: OS << "note: "; break;
+  }
+
   DiagnosticPrinterRawOStream DP(OS);
   DI.print(DP);
   OS << '\n';
-  exit(1);
+
+  if (DI.getSeverity() == DS_Error)
+    exit(1);
 }
 
 int main(int argc, char **argv) {