DWARFVerifier: Basic verification of .debug_names

Summary:
This patch adds basic .debug_names verification capabilities to the
DWARF verifier. Right now, it checks that the headers and abbreviation
tables of the individual name indexes can be parsed correctly, it
verifies the buckets table and the cross-checks the CU lists for
consistency. I intend to add further checks in follow-up patches.

Reviewers: JDevlieghere, aprantl, probinson, dblaikie

Subscribers: vleschuk, echristo, clayborg, llvm-commits

Differential Revision: https://reviews.llvm.org/D44211

llvm-svn: 327011
diff --git a/llvm/test/tools/llvm-dwarfdump/X86/debug-names-verify-abbrev-duplicate.s b/llvm/test/tools/llvm-dwarfdump/X86/debug-names-verify-abbrev-duplicate.s
new file mode 100644
index 0000000..5c5075c
--- /dev/null
+++ b/llvm/test/tools/llvm-dwarfdump/X86/debug-names-verify-abbrev-duplicate.s
@@ -0,0 +1,64 @@
+# RUN: llvm-mc -triple x86_64-pc-linux %s -filetype=obj | \
+# RUN:   not llvm-dwarfdump -verify - | FileCheck %s
+
+# CHECK: Duplicate abbreviation code.
+
+	.section	.debug_str,"MS",@progbits,1
+.Lstring_producer:
+	.asciz	"Hand-written dwarf"
+
+	.section	.debug_abbrev,"",@progbits
+.Lsection_abbrev:
+	.byte	1                       # Abbreviation Code
+	.byte	17                      # DW_TAG_compile_unit
+	.byte	1                       # DW_CHILDREN_yes
+	.byte	37                      # DW_AT_producer
+	.byte	14                      # DW_FORM_strp
+	.byte	19                      # DW_AT_language
+	.byte	5                       # DW_FORM_data2
+	.byte	0                       # EOM(1)
+	.byte	0                       # EOM(2)
+	.byte	0                       # EOM(3)
+
+	.section	.debug_info,"",@progbits
+.Lcu_begin0:
+	.long	.Lcu_end0-.Lcu_start0   # Length of Unit
+.Lcu_start0:
+	.short	4                       # DWARF version number
+	.long	.Lsection_abbrev        # Offset Into Abbrev. Section
+	.byte	8                       # Address Size (in bytes)
+	.byte	1                       # Abbrev [1] DW_TAG_compile_unit
+	.long	.Lstring_producer       # DW_AT_producer
+	.short	12                      # DW_AT_language
+	.byte	0                       # End Of Children Mark
+.Lcu_end0:
+
+	.section	.debug_names,"",@progbits
+	.long	.Lnames_end0-.Lnames_start0 # Header: contribution length
+.Lnames_start0:
+	.short	5                       # Header: version
+	.short	0                       # Header: padding
+	.long	1                       # Header: compilation unit count
+	.long	0                       # Header: local type unit count
+	.long	0                       # Header: foreign type unit count
+	.long	0                       # Header: bucket count
+	.long	0                       # Header: name count
+	.long	.Lnames_abbrev_end0-.Lnames_abbrev_start0 # Header: abbreviation table size
+	.long	0                       # Header: augmentation length
+	.long	.Lcu_begin0             # Compilation unit 0
+.Lnames_abbrev_start0:
+	.byte	46                      # Abbrev code
+	.byte	46                      # DW_TAG_subprogram
+	.byte	3                       # DW_IDX_die_offset
+	.byte	6                       # DW_FORM_data4
+	.byte	0                       # End of abbrev
+	.byte	0                       # End of abbrev
+	.byte	46                      # Abbrev code
+	.byte	46                      # DW_TAG_subprogram
+	.byte	3                       # DW_IDX_die_offset
+	.byte	6                       # DW_FORM_data4
+	.byte	0                       # End of abbrev
+	.byte	0                       # End of abbrev
+	.byte	0                       # End of abbrev list
+.Lnames_abbrev_end0:
+.Lnames_end0: