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

[grimar]

Summary

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.

Depends on D66976, D66998.

[jhenderson]

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

38

st_name -> sh_name

39

"We that we can still print..."

42

Do we get any warning message here? If we do, I think we should check it. If we don't, I feel like we should.

[grimar]

• Addressed review comments.

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

42

No, we don't have a warning, because the error is silently consumed:
https://github.com/llvm-mirror/llvm/blob/master/tools/llvm-nm/llvm-nm.cpp#L1102

There are 16 places around in total where errors are ignored in the same way.

I did a quick test to check what GNU nm do. It prints nothing, returns 1 and reports an error:

umb@ubuntu:~/tests/66$ nm format-sysv-section.test.tmp2.o --format=sysv
bfd plugin: format-sysv-section.test.tmp2.o: ELF section name out of range
nm: format-sysv-section.test.tmp2.o: invalid string offset 65535 >= 35 for section `.shstrtab'
nm: format-sysv-section.test.tmp2.o: invalid string offset 65535 >= 35 for section `.shstrtab'
nm: format-sysv-section.test.tmp2.o: bad value
umb@ubuntu:~/tests/66$ echo $?
1

Given that difference I do not think we should add warnings/errors in this patch, since it only adds a test case for
a mistype fixed and used to check we don't fail with LLVM_ENABLE_ABI_BREAKING_CHECKS.
We should probably decide what the behavior we want to have on errors in llvm-nm first?

[jhenderson]

LGTM.

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

42

Sorry, yes, I wasn't saying that a new error should be part of this change.

[grimar]

Reverted in rL370662

[grimar]

Recommitted as rL370669.

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

-# 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
   Type:    ET_REL
   Machine: EM_X86_64
 Sections:
   - Name:  .text
     Type:  SHT_PROGBITS

 
 # CHECK:      os               {{.*}}|
 # CHECK-NEXT: proc             {{.*}}|
 # CHECK-NEXT: reserved         {{.*}}|
 # CHECK-NEXT: symbol           {{.*}}|     |.text
 # 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