llvm-dwp: Add assert text

Post-commit feedback from Eric Christopher on r265452.

llvm-svn: 266225

1 files changed, 3 insertions, 1 deletions

diff --git a/llvm/tools/llvm-dwp/llvm-dwp.cpp b/llvm/tools/llvm-dwp/llvm-dwp.cpp
index de19eb9e24b..40bea8eabc6 100644
--- a/llvm/tools/llvm-dwp/llvm-dwp.cpp
+++ b/llvm/tools/llvm-dwp/llvm-dwp.cpp
@@ -131,7 +131,9 @@ static const char *getIndexedString(uint32_t Form, DataExtractor InfoData,
                                     StringRef Str) {
   if (Form == dwarf::DW_FORM_string)
     return InfoData.getCStr(&InfoOffset);
-  assert(Form == dwarf::DW_FORM_GNU_str_index);
+  assert(Form == dwarf::DW_FORM_GNU_str_index && "Only string and str_index "
+                                                 "forms are supported for DWP "
+                                                 "string attributes");
   auto StrIndex = InfoData.getULEB128(&InfoOffset);
   DataExtractor StrOffsetsData(StrOffsets, true, 0);
   uint32_t StrOffsetsOffset = 4 * StrIndex;