[elf2yaml] Fix dumping a debug section whose name is not recognized.

If the debug section's name isn't recognized, it should be
dumped as a raw content section.

Reviewed By: jhenderson, grimar

Differential Revision: https://reviews.llvm.org/D87346

llvm/test/tools/obj2yaml/ELF/DWARF/unrecognized-debug-section.yaml

@@ -0,0 +1,19 @@
+## Test dumping a debug section when its name is not recognized by obj2yaml.
+
+# RUN: yaml2obj %s | obj2yaml | FileCheck %s
+
+#      CHECK: Sections:
+# CHECK-NEXT:   - Name:    .debug_foo
+# CHECK-NEXT:     Type:    SHT_PROGBITS
+# CHECK-NEXT:     Content: '01020304'
+# CHECK-NEXT: ...
+
+--- !ELF
+FileHeader:
+  Class: ELFCLASS64
+  Data:  ELFDATA2LSB
+  Type:  ET_EXEC
+Sections:
+  - Name:    .debug_foo
+    Type:    SHT_PROGBITS
+    Content: '01020304'

llvm/tools/obj2yaml/elf2yaml.cpp

@@ -416,6 +416,8 @@ Optional<DWARFYAML::Data> ELFDumper<ELFT>::dumpDWARFSections(
         Err = dumpDebugARanges(*DWARFCtx.get(), DWARF);
       else if (RawSec->Name == ".debug_str")
         Err = dumpDebugStrings(*DWARFCtx.get(), DWARF);
+      else
+        continue;
 
       // If the DWARF section cannot be successfully parsed, emit raw content
       // instead of an entry in the DWARF section of the YAML.