[DWARF] Warn on unsupport DWARF versions and content (#5120)

Unfortunately there isn't a single place where an error may occur. I tested on
several files with different flags and added sufficient warnings so that we warn
on them all.

1 files changed, 10 insertions, 3 deletions

diff --git a/src/wasm/wasm-debug.cpp b/src/wasm/wasm-debug.cpp
index 8de691272..3e0749f36 100644
--- a/src/wasm/wasm-debug.cpp
+++ b/src/wasm/wasm-debug.cpp
@@ -64,6 +64,10 @@ struct BinaryenDWARFInfo {
     uint8_t addrSize = AddressSize;
     bool isLittleEndian = true;
     context = llvm::DWARFContext::create(sections, addrSize, isLittleEndian);
+    if (context->getMaxVersion() > 4) {
+      std::cerr << "warning: unsupported DWARF version ("
+                << context->getMaxVersion() << ")\n";
+    }
   }
 };
 
@@ -162,8 +166,8 @@ struct LineState {
           }
           default: {
             // An unknown opcode, ignore.
-            std::cerr << "warning: unknown subopcopde " << opcode.SubOpcode
-                      << '\n';
+            std::cerr << "warning: unknown subopcode " << opcode.SubOpcode
+                      << " (this may be an unsupported version of DWARF)\n";
           }
         }
         break;
@@ -180,7 +184,10 @@ struct LineState {
         return true;
       }
       case llvm::dwarf::DW_LNS_advance_pc: {
-        assert(table.MinInstLength == 1);
+        if (table.MinInstLength != 1) {
+          std::cerr << "warning: bad MinInstLength "
+                       "(this may be an unsupported DWARF version)";
+        }
         addr += opcode.Data;
         break;
       }