[llvm-nm] - Add a test case for case when we dump a symbol that belongs to a section with a broken sh_name.

It adds a test case for a problem fixed by D66976.

It was introduced by me in D66089.
The error reported was never consumed because of a wrong variable name used,
so it could fail when LLVM_ENABLE_ABI_BREAKING_CHECKS is used.

Differential revision: https://reviews.llvm.org/D67002

llvm-svn: 370661

llvm/test/tools/llvm-nm/format-sysv-section.test

@@ -1,7 +1,7 @@
-# RUN: yaml2obj %s > %t.o
-# RUN: llvm-nm %t.o --format=sysv | FileCheck %s
+# RUN: yaml2obj --docnum=1 %s > %t1.o
+# RUN: llvm-nm %t1.o --format=sysv | FileCheck %s
 
-!ELF
+--- !ELF
 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
@@ -33,3 +33,27 @@ Symbols:
 # CHECK-NEXT: symbol_absolute  {{.*}}|     |*ABS*
 # CHECK-NEXT: symbol_common    {{.*}}|     |*COM*
 # CHECK-NEXT: symbol_undefined {{.*}}|     |*UND*
+
+## Here we have a symbol that belongs to a section with a broken name
+## (sh_name offset goes past the end of the sections name string table).
+## We test that we can still print a reasonable output and don't crash/assert.
+
+# RUN: yaml2obj --docnum=2 %s > %t2.o
+# RUN: llvm-nm %t2.o --format=sysv | FileCheck %s --check-prefix=ERR
+
+# ERR: foo |0000000000000000| ? | NOTYPE|0000000000000000| |
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_REL
+  Machine: EM_X86_64
+Sections:
+  - Name:  .broken
+    Type:  SHT_PROGBITS
+    Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
+    ShName: 0xffff
+Symbols:
+  - Name:    foo
+    Section: .broken