[llvm-dwarfdump][test] Add tests for dumping the .debug_line_str section.

[Higuoxing]

Summary

This patch adds tests for dumping the .debug_line_str section. The
dumper of the debug_line_str section is able to write nonprintable
strings as escaped chars while the dumper of the debug_str and
debug_str.dwo sections cannot. I will fix them and add tests for them
in a follow-up patch.

[jhenderson]

It sounds to me like the .debug_line_str should be using the same dumper as the .debug_str and .debug_str.dwo dumpers. There's no difference in the section format as far as I'm aware.

llvm/test/tools/llvm-dwarfdump/debug-line-str.yaml

5

I'd put this comment above the RUN line. Same below.

24

27

It might be clearer if this comment was divided into individual characters. It took me several attempts to figure it out. (Maybe do '\t', '\0', '\001', '\\', '0', '0', '1')

[Higuoxing]

Address comments.

Thanks for reviewing!

[jhenderson]

LGTM.

llvm/test/tools/llvm-dwarfdump/debug-line-str.yaml

+## a) Test that llvm-dwarfdump is able to dump the debug_line_str section.
+
+##                        "abc\0cba\0\0"
+# RUN: yaml2obj -DCONTENT="616263006362610000" %s -o %t1.o
+# RUN: llvm-dwarfdump --debug-line-str %t1.o | FileCheck %s --check-prefix=LINE-STR
+
+#       LINE-STR: .debug_line_str contents:
+#  LINE-STR-NEXT: 0x00000000: "abc"
+#  LINE-STR-NEXT: 0x00000004: "cba"
+#  LINE-STR-NEXT: 0x00000008: ""
+# LINE-STR-EMPTY:
+
+--- !ELF
+FileHeader:
+  Class: ELFCLASS64
+  Data: ELFDATA2LSB
+  Type: ET_EXEC
+Sections:
+  - Name:    .debug_line_str
+    Type:    SHT_PROGBITS
+    Content: [[CONTENT]]
+
+## b) Test how we dump unprintable chars.
+
+##                        ['\t', '\0', '\001', '\0', '\\', '0', '0', '1', '\0']
+# RUN: yaml2obj -DCONTENT="090001005C30303100" %s -o %t2.o
+# RUN: llvm-dwarfdump --debug-line-str %t2.o | FileCheck %s --check-prefix=ESCAPED
+
+#      ESCAPED: .debug_line_str contents:
+# ESCAPED-NEXT: 0x00000000: "\t"
+# ESCAPED-NEXT: 0x00000002: "\001"
+# ESCAPED-NEXT: 0x00000004: "\\001"